Hybrid vehicles

• US 7,237,634 B2
• Filed: 01/13/2006
• Issued: 07/03/2007
• Est. Priority Date: 09/14/1998
• Status: Expired due to Term

• Current Assignee: Abell Foundation Incorporated
• Original Assignee: Paice LLC
• Inventors: Louckes, Theodore, Severinsky, Alex J.
• Primary Examiner(s): Dunn; David R.
• Application Number:
  US11/229,762
• Publication Number:
  US 20060100057A1
• Time in Patent Office: 536 Days
• Field of Search: 180/65.2, 180/65.3, 180/65.4, 180/65.8, 180/165, 477/2, 477/3, 701/54
• US Class Current: 180/65.23
• CPC Class Codes: B60H 1/004 for vehicles having a combustion engine and electric drive means, e.g. hybrid electric vehicles
• CPC Class Codes: B60H 1/3222 characterised by the compressor driving arrangements, e.g. clutches, transmissions or multiple drives B60H1/3208, B60H1/3226 take precedence
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 6/22 characterised by apparatus, components or means specially adapted for HEVs
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2210/20 AC to AC converters
• CPC Class Codes: B60L 2220/12 Induction machines
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2220/16 DC brushless machines
• CPC Class Codes: B60L 2240/34 Cabin temperature
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/443 : Torque
• CPC Class Codes: B60L 2240/445 : Temperature
• CPC Class Codes: B60L 2260/28 : Four wheel or all wheel drive
• CPC Class Codes: B60L 2270/145 : Structure borne vibrations
• CPC Class Codes: B60L 50/16 : with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 : by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 53/00 : Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
• CPC Class Codes: B60L 53/20 : characterised by converters located in the vehicle
• CPC Class Codes: B60L 58/10 : for monitoring or controlling batteries
• CPC Class Codes: B60L 58/12 : responding to state of charge [SoC]
• CPC Class Codes: B60L 7/18 : Controlling the braking effect B60L7/12, B60L7/14, B60L7/16 take precedence
• CPC Class Codes: B60L 7/26 : Controlling the braking effect
• CPC Class Codes: B60T 11/18 : Connection thereof to initiating means
• CPC Class Codes: B60T 13/586 : the retarders being of the electric type
• CPC Class Codes: B60T 2270/60 : Regenerative braking
• CPC Class Codes: B60T 2270/604 : Merging friction therewith; Adjusting their repartition
• CPC Class Codes: B60T 7/06 : Disposition of pedal
• CPC Class Codes: B60T 8/17 : Using electrical or electronic regulation means to control braking detecting or indicating faulty operation B60T8/885
• CPC Class Codes: B60T 8/172 : Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence
• CPC Class Codes: B60W 10/06 : including control of combustion engines
• CPC Class Codes: B60W 10/08 : including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/18 : including control of braking systems
• CPC Class Codes: B60W 10/26 : for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/00 : Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/10 : Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 20/14 : in conjunction with braking regeneration
• CPC Class Codes: B60W 20/15 : Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 20/30 : Control strategies involving selection of transmission gear ratio control of change speed gearings, together with other vehicle sub-units B60W10/10; HEV transmission gearing B60K6/36; gearings and control thereof F16H
• CPC Class Codes: B60W 2510/0633 : Turbocharger state
• CPC Class Codes: B60W 2510/0657 : Engine torque
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2530/16 : Driving resistance
• CPC Class Codes: B60W 2540/12 : Brake pedal position
• CPC Class Codes: B60W 2710/08 : Electric propulsion units
• CPC Class Codes: B60W 2710/18 : Braking system
• CPC Class Codes: B60W 2710/244 : Charge state
• CPC Class Codes: B60W 30/18127 : Regenerative braking
• CPC Class Codes: B60Y 2200/91 : Electric vehicles
• CPC Class Codes: B60Y 2200/92 : Hybrid vehicles
• CPC Class Codes: B60Y 2300/18125 : Regenerative braking
• CPC Class Codes: B60Y 2300/91 : Battery charging
• CPC Class Codes: B60Y 2400/112 : Batteries
• CPC Class Codes: B60Y 2400/435 : Supercharger or turbochargers
• CPC Class Codes: B60Y 2400/81 : Braking systems
• CPC Class Codes: F01N 3/2013 : using electric or magnetic heating means
• CPC Class Codes: F02B 37/00 : Engines characterised by provision of pumps driven at least for part of the time by exhaust
• CPC Class Codes: F02B 37/16 : by bypassing charging air
• CPC Class Codes: F02B 37/18 : by bypassing exhaust from the inlet to the outlet of turbine or to the atmosphere
• CPC Class Codes: F02D 2250/18 : Control of the engine output torque
• CPC Class Codes: F02D 41/0007 : for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02M 35/10157 : Supercharged engines
• CPC Class Codes: F02M 35/10163 : having air intakes specially adapted to selectively deliver naturally aspirated fluid or supercharged fluid
• CPC Class Codes: F02N 11/0818 : Conditions for starting or stopping the engine or for deactivating the idle-start-stop mode
• CPC Class Codes: F02N 2200/061 : Battery state of charge [SOC]
• CPC Class Codes: H01M 10/4207 : for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 2220/20 : Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: Y02A 50/20 : Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles
• CPC Class Codes: Y10S 903/903 : having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/904 : Component specially adapted for hev
• CPC Class Codes: Y10S 903/907 : Electricity storage, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/93 : Conjoint control of different elements
• CPC Class Codes: Y10S 903/946 : Characterized by control of driveline clutch
• CPC Class Codes: Y10S 903/947 : Characterized by control of braking, e.g. blending of regeneration, friction braking

Abstract

A hybrid vehicle comprises an internal combustion engine, a traction motor, a starter motor, and a battery bank, all controlled by a microprocessor in accordance with the vehicle'"'"'s instantaneous torque demands so that the engine is run only under conditions of high efficiency, typically only when the load is at least equal to 30% of the engine'"'"'s maximum torque output. In some embodiments, a turbocharger may be provided, activated only when the load exceeds the engine'"'"'s maximum torque output for an extended period; a two-speed transmission may further be provided, to further broaden the vehicle'"'"'s load range. A hybrid brake system provides regenerative braking, with mechanical braking available in the event the battery bank is fully charged, in emergencies, or at rest; a control mechanism is provided to control the brake system to provide linear brake feel under varying circumstances.

Claims

1. A hybrid vehicle, comprising:

one or more wheels;

an internal combustion engine operable to propel the hybrid vehicle by providing torque to the one or more wheels;

a first electric motor coupled to the engine;

a second electric motor operable to propel the hybrid vehicle by providing torque to the one or more wheels;

a battery coupled to the first and second electric motors, operable to;

provide current to the first and/or the second electric motors; and

accept current from the first and second electric motors; and

a controller, operable to control the flow of electrical and mechanical power between the engine, the first and the second electric motors, and the one or more wheels;

wherein the controller is operable to operate the engine when torque required from the engine to propel the hybrid vehicle and/or to drive one or more of the first or the second motors to charge the battery is at least equal to a setpoint (SP) above which the torque produced by the engine is efficiently produced, and wherein the torque produced by the engine when operated at the SP is substantially less than the maximum torque output (MTO) of the engine.

2. The hybrid vehicle of claim 1, wherein the controller is operable to stop the engine when the torque required to propel the vehicle is less than the SP.

3. The hybrid vehicle of claim 1, wherein the controller is operable to stop the engine when the torque required to propel the vehicle and/or charge the battery is less than the SP.

4. The hybrid vehicle of claim 1, wherein to operate the engine, the controller is operable to start the engine via the first electric motor if the engine is not already running.

5. The hybrid vehicle of claim 1, wherein the controller is further operable to monitor patterns of vehicle operation over time and vary the SP accordingly.

6. The hybrid vehicle of claim 1, wherein the controller is further operable to:

monitor road load (RL) on the hybrid vehicle over time; and

control transition between propulsion of the hybrid vehicle by the first and/or the second electric motors to propulsion by the engine responsive to the RL reaching the SP, wherein the transition only occurs when;

the RL>

the SP for at least a first length of time;

or

the RL>

a second setpoint (SP2), wherein the SP2>

the SP.

7. The hybrid vehicle of claim 6, wherein if the engine is not started, the controller is operable to start the engine for the transition between propulsion of the hybrid vehicle by the first and/or the second electric motors to propulsion by the engine.

8. The hybrid vehicle of claim 6, wherein the controller is further operable to control transition from propulsion of the hybrid vehicle by the engine to propulsion by the first and/or the second electric motors such that the transition occurs only when the RL<

the SP for at least a second length of time.

9. The hybrid vehicle of claim 8, wherein the first length of time is the same as the second length of time.

10. The hybrid vehicle of claim 8, wherein the first length of time and the second length of time are predetermined.

11. The hybrid vehicle of claim 8, wherein the controller is further operable to stop the engine after the transition between propulsion of the hybrid vehicle by the engine to propulsion by the first and/or the second electric motors.

12. The hybrid vehicle of claim 1, wherein the controller is operable to vary the SP as a function of speed of the engine.

13. The hybrid vehicle of claim 1, wherein the SP is at least approximately 20% of the MTO of the engine when normally-aspirated.

14. The hybrid vehicle of claim 1 wherein the SP is at least approximately 30% of the MTO of the engine when normally-aspirated.

15. The hybrid vehicle of claim 1, wherein the SP is less than approximately 70% of the MTO of the engine when normally-aspirated.

16. The hybrid vehicle of claim 1, wherein the controller is operable to implement a plurality of operating modes responsive to road load (RL) and the SP, wherein both the RL and the SP are expressed as percentages of the MTO of the engine when normally-aspirated, and wherein the operating modes comprise:

a low-load mode I, wherein, when the RL<

the SP, the second electric motor is operable to provide torque to propel the hybrid vehicle;

a highway cruising mode IV, wherein, when the SP<

the RL<

the MTO, the engine is operable to provide torque to propel the hybrid vehicle, and wherein the controller is operable to start the engine if the engine is not running to enter the highway cruising mode IV; and

an acceleration mode V, wherein, when the RL>

the MTO, the engine, the first electric motor, and/or the second electric motor is operable to provide torque to propel the hybrid vehicle, and wherein the controller is operable to start the engine if the engine is not running to enter the acceleration mode V.

17. The hybrid vehicle of claim 16, wherein the controller is operable to decouple the engine and the first electric motor from the one or more wheels during operation in the mode I and couple the engine and the first electric motor to the one or more wheels during operation in the modes IV and V.

18. The hybrid vehicle of claim 16, wherein the plurality of operating modes further comprise a low-speed battery charging mode II, wherein, when the RL<

the SP and a state of charge of the battery is below a predetermined level;

the controller is operable to decouple the engine and the first electric motor from the one or more wheels and start the engine if the engine is not running to enter the battery charging mode II;

the second electric motor is operable to provide torque to propel the hybrid vehicle; and

the engine is operable to provide torque at least equal to the SP to the first motor for charging the battery.

19. The hybrid vehicle of claim 16, wherein the controller is operable to control direct transition from operation of the hybrid vehicle in the mode I to operation of the hybrid vehicle in the mode V in response to operator input, and wherein the operator input specifies a rapid increase in torque to be applied to the one or more wheels of the hybrid vehicle.

20. The hybrid vehicle of claim 16, further comprising a turbocharger controllably coupled to the internal combustion engine, operable to increase the MTO of the engine;

wherein the plurality of operation modes further comprise a sustained high-power turbocharged mode VI, wherein, when the RL>

the MTO for more than a predetermined time T, the controller is operable to engage the turbocharger to increase the effective MTO of the engine.

21. The hybrid vehicle of claim 20, wherein the controller is operable to vary the time T with respect to a state of charge of the battery.

22. The hybrid vehicle of claim 1, further comprising a turbocharger controllably coupled to the internal combustion engine, operable to increase the MTO of the engine.

23. The hybrid vehicle of claim 1, wherein the controller is operable to receive operator input of a desired cruising speed, and thereafter control instantaneous torque output of the engine and/or one or more of the first or the second electric motors in accordance with variation in RL so as to maintain a substantially constant vehicle speed.

24. The hybrid vehicle of claim 1, wherein the battery is operable to be regeneratively charged when instantaneous torque output by the internal combustion engine>

the RL, when the RL is negative, and/or when braking is initiated by the operator.

25. The hybrid vehicle of claim 1, wherein total torque available to the one or more wheels from the engine is no greater than total torque available from the first and second electric motors combined.

26. The hybrid vehicle of claim 1, wherein the engine and first electric motor are coupled to a first set of the one or more wheels of the hybrid vehicle and the second electric motor is coupled to a second set of the one or more wheels of the hybrid vehicle.

27. The hybrid vehicle of claim 1, further comprising a variable-ratio transmission disposed between the engine and the one or more wheels of the hybrid vehicle.

28. The hybrid vehicle of claim 1, wherein the controller is operable to rotate the engine via the first electric motor before starting the engine such that cylinders of the engine are heated by compression of air therein.

29. The hybrid vehicle of claim 1, wherein the controller is operable to limit a rate of change of torque produced by the engine, such that combustion of fuel within the engine occurs substantially at a stoichiometric ratio, and wherein if the engine is incapable of supplying an instantaneous torque required, the controller is operable to transfer additional torque from one or more of the first or the second electric motors.

30. The hybrid vehicle of claim 1, wherein the engine is controllably coupled to the one or more wheels of the hybrid vehicle by a clutch.

31. The hybrid vehicle of claim 30, wherein the clutch connects a first output shaft of or driven by the engine and the first electric motor with a second output shaft of or driven by the second electric motor coupled to the one or more wheels, and wherein the controller is operable to control the speeds of the engine and the first electric motor and of the second motor such that when the clutch is engaged, the speeds of the first and second output shafts are substantially equal.

32. The hybrid vehicle of claim 1, wherein the controller is operable to start and operate the engine at torque output levels less than SP under abnormal and transient conditions to satisfy drivability and/or safety considerations.

56. The hybrid vehicle of claim 1, wherein a ratio of maximum DC voltage to maximum current supplied is at least 2.5.

57. The hybrid vehicle of claim 56, wherein the maximum DC voltage is at least approximately 500 volts.

58. The hybrid vehicle of claim 56, wherein the maximum current is less than approximately 150 amperes.

59. The hybrid vehicle of claim 1, wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

60. The hybrid vehicle of claim 1, wherein a maximum current supplied from said battery is less than approximately 150 amperes.

61. The hybrid vehicle of claim 1, wherein the hybrid vehicle further comprises:

a first alternating current-direct current (AC-DC) converter having an AC side coupled to said second electric motor, operable to accept AC or DC current and convert the current to DC or AC current respectively;

a second AC-DC converter coupled to said first electric motor, at least operable to accept AC current and convert the current to DC;

wherein said battery is coupled to a DC side of said AC-DC converters, wherein said battery is operable to store DC energy received from said AC-DC converters and provide DC energy to at least said first AC-DC converter for providing power to at least said second electric motor; and

wherein a ratio of maximum DC voltage on the DC side of at least said first AC-DC converter coupled to said second electric motor to current supplied from said battery to at least said first AC-DC converter, when maximum current is so supplied, is at least 2.5.

62. The hybrid vehicle of claim 61, wherein the maximum DC voltage on the DC side of either of said AC-DC converters is at least approximately 500 volts.

63. The hybrid vehicle of claim 61, wherein the maximum DC current on the DC side of either of said AC-DC converters is less than approximately 150 amperes.

64. The hybrid vehicle of claim 61, wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

65. The hybrid vehicle of claim 61, wherein a maximum current supplied from said battery is less than approximately 150 amperes.

66. The hybrid vehicle of claim 27, wherein said variable-ratio transmission disposed between the engine and the one or more wheels of the hybrid vehicle comprises a planetary gear mechanism.

67. The hybrid vehicle of claim 1, wherein the second electric motor is sufficiently powerful to provide acceleration of said vehicle sufficient to conform to the Federal urban cycle driving fuel mileage test without use of torque from the engine to propel the vehicle.

79. The hybrid vehicle of claim 1, wherein the second electric motor is sufficiently powerful to provide acceleration of said vehicle sufficient to conform to the Federal urban cycle driving fuel mileage test without use of torque from the engine to propel the vehicle.

33. A method for controlling a hybrid vehicle, comprising:

determining instantaneous road load (RL) required to propel the hybrid vehicle responsive to an operator command;

operating at least one electric motor to propel the hybrid vehicle when the RL required to do so is less than a setpoint (SP);

operating an internal combustion engine of the hybrid vehicle to propel the hybrid vehicle when the RL required to do so is between the SP and a maximum torque output (MTO) of the engine, wherein the engine is operable to efficiently produce torque above the SP, and wherein the SP is substantially less than the MTO;

operating both the at least one electric motor and the engine to propel the hybrid vehicle when the torque RL required to do so is more than the MTO; and

monitoring patterns of vehicle operation over time and varying the SP accordingly.

34. The method of claim 33, further comprising:

turning off the engine when the torque required to propel the vehicle is less than the SP.

35. The method of claim 33, further comprising:

turning off the engine when the torque required to propel the vehicle and/or charge the battery is less than the SP.

36. The method of claim 33, further comprising:

monitoring a state of charge of a battery comprised in the hybrid vehicle, wherein the battery is operable to;

store power from the at least one electric motor and/or the engine; and

transmit power to the at least one electric motor to propel the hybrid vehicle.

37. The method of claim 33, further comprising:

operating the engine to charge the battery when the state of charge of the battery indicates the need to do so, wherein the engine is operable to provide torque at least equal to the SP to propel the hybrid vehicle and to drive the at least one electric motor to charge the battery, wherein a first portion of the torque equal to RL is used to propel the hybrid vehicle, wherein a second portion of the torque in excess of RL is used to drive the at least one electric motor to charge the battery, and wherein said operating the engine to charge the battery comprises if the engine is not already running, starting the engine.

38. The method of claim 33, wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle and said operating both the at least one electric motor and the engine to propel the hybrid vehicle, each comprises:

if the engine is not already running, starting the engine.

39. The method of claim 33, further comprising:

monitoring the RL over time;

wherein said operating the internal combustion engine to propel the hybrid vehicle is performed when;

the RL>

the SP for at least a predetermined time;

or

the RL>

a second setpoint (SP2), wherein the SP2 is a larger percentage of the MTO than the SP.

40. The method of claim 33, further comprising:

monitoring the RL over time;

wherein said operating the at least one electric motor to propel the hybrid vehicle is performed when the RL<

the SP for at least a predetermined amount of time.

41. The method of claim 33, further comprising:

receiving operator input specifying a desired cruising speed;

controlling instantaneous engine torque output and operation of the at least one electric motor in accordance with variation in the RL to maintain the speed of the hybrid vehicle according to the desired cruising speed.

42. The method of claim 33, wherein the SP is at least approximately 30% of the MTO.

43. The method of claim 33,

wherein the hybrid vehicle is operated in a plurality of operating modes corresponding to values for the RL and the SP;

wherein said operating the at least one electric motor to drive the hybrid vehicle composes a low-load operation mode I;

wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle composes a high-way cruising operation mode IV; and

wherein said operating both the at least one electric motor and the engine to propel the hybrid vehicle composes an acceleration operation mode V.

44. The method of claim 43, further comprising:

decoupling the engine from wheels of the hybrid vehicle for operation in mode I; and

coupling the engine to the wheels for operation in modes IV and V.

45. The method of claim 43, wherein the at least one electric motors comprises a first electric motor and a second electric motor, the method further comprising:

monitoring a state of charge of a battery comprised in the hybrid vehicle, wherein the battery is operable to store power from the engine and/or the at least one electric motor and transmit power to the at least one electric motor to propel the vehicle;

operating the engine to charge the battery when the state of charge of the battery is below a predetermined level and when the RL<

the SP, wherein said operating the engine to charge the battery composes a low-load battery charging mode II, and wherein said operating the engine to charge the battery comprises;

decoupling the engine from wheels of the hybrid vehicle; and

the engine providing torque at least equal to the SP to the first electric motor to charge the battery;

wherein during said operating the engine to charge the battery when the state of charge of the battery is below a predetermined level, the hybrid vehicle is propelled by torque provided by the second electric motor in response to energy supplied by the battery.

46. The method of claim 43, further comprising:

receiving operator input specifying a change in required torque to be applied to wheels of the hybrid vehicle; and

if the received operator input specifies a rapid increase in the required torque, changing operation from operating mode I directly to operating mode V.

47. The method of claim 43, wherein the hybrid vehicle further comprises a turbocharger controllably coupled to the engine, and wherein said operating both the engine and the at least one electric motor occurs when the RL>

the MTO for less than a predetermined time T, wherein the method further comprises;

operating the turbocharger to increase the MTO of the engine when desired, wherein said operating the turbocharger to increase the MTO of the engine occurs when the RL>

the MTO for more than the predetermined time T, and wherein said operating the turbocharger composes a turbocharged operation mode VI.

48. The method of claim 47, further comprising:

varying the time T responsive to the state of charge of the battery.

49. The method of claim 33, wherein the hybrid vehicle further comprises a turbocharger controllably coupled to the engine, wherein the method further comprises:

operating the turbocharger to increase the MTO of the engine when desired.

50. The method of claim 33, further comprising:

regeneratively charging a battery of the hybrid vehicle when instantaneous torque output of the engine>

the RL, when the RL is negative, and/or when braking is initiated by an operator of the hybrid vehicle.

51. The method of claim 33, wherein the hybrid vehicle comprises a variable-ratio transmission disposed between the engine and the wheels of the hybrid vehicle.

52. The method of claim 33, wherein the engine is controllably coupled to one or more wheels of the hybrid vehicle by a clutch.

53. The method of claim 33, further comprising:

controlling the engine such that combustion of fuel within the engine occurs substantially at a stoichiometric ratio, wherein said controlling the engine comprises limiting a rate of change of torque output of the engine; and

if the engine is incapable of supplying instantaneous torque required to propel the hybrid vehicle, supplying additional torque from the at least one electric motor.

54. The method of claim 33, further comprising:

rotating the engine before starting the engine such that its cylinders are heated by compression of air therein.

55. The method of claim 33, further comprising:

operating the engine at torque output levels less than the SP under abnormal and transient conditions to satisfy drivability and/or safety considerations.

68. The method of claim 33,

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein a ratio of maximum DC voltage to maximum current supplied is at least 2.5.

69. The method of claim 68, wherein the maximum DC voltage is at least approximately 500 volts.

70. The method of claim 68, wherein the maximum current is less than approximately 150 amperes.

71. The method of claim 33,

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

72. The method of claim 33,

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein a maximum current supplied from said battery is less than approximately 150 amperes.

73. The method of claim 33, wherein the at least one electric motor comprises a first electric motor and a second electric motor, the method further comprising:

operating a first alternating current-direct current (AC-DC) converter having an AC side coupled to the second electric motor, wherein said operating the first AC-DC converter comprises accepting AC or DC current and converting the current to DC or AC current respectively;

operating a second AC-DC converter coupled to a first electric motor, wherein said operating the second AC-DC converter comprises accepting AC current and converting the current to DC;

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein said battery is coupled to a DC side of said AC-DC converters;

storing DC energy received from said AC-DC converters and providing DC energy to at least said first AC-DC converter for providing power to at least said second electric motor; and

wherein a ratio of maximum DC voltage on the DC side of at least said first AC-DC converter coupled to said second electric motor to current supplied from said battery to at least said first AC-DC converter, when maximum current is so supplied, is at least 2.5.

74. The method of claim 73, wherein the maximum DC voltage on the DC side of either of said AC-DC converters is at least approximately 500 volts.

75. The method of claim 73, wherein the maximum DC current on the DC side of either of said AC-DC converters is less than approximately 150 amperes.

76. The method of claim 73, wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

77. The method of claim 73, wherein a maximum current supplied from said battery is less than approximately 150 amperes.

78. The method of claim 51, wherein said variable-ratio transmission comprises a planetary gear mechanism.

80. A method for controlling a hybrid vehicle, comprising:

determining instantaneous road load (RL) required to propel the hybrid vehicle responsive to an operator command;

monitoring the RL over time;

operating at least one electric motor to propel the hybrid vehicle when the RL required to do so is less than a setpoint (SP);

operating an internal combustion engine of the hybrid vehicle to propel the hybrid vehicle when the RL required to do so is between the SP and a maximum torque output (MTO) of the engine, wherein the engine is operable to efficiently produce torque above the SP, and wherein the SP is substantially less than the MTO; and

wherein said operating the internal combustion engine to propel the hybrid vehicle is performed when;

the RL>

the SP for at least a predetermined time;

or

the RL>

a second setpoint (SP2), wherein the SP2 is a larger percentage of the MTO than the SP; and

operating both the at least one electric motor and the engine to propel the hybrid vehicle when the torque RL required to do so is more than the MTO.

81. The method of claim 80,

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein a ratio of maximum DC voltage to maximum current supplied is at least 2.5.

82. The method of claim 81, wherein the maximum DC voltage is at least approximately 500 volts.

83. The method of claim 81, wherein the maximum current is less than approximately 150 amperes.

84. The method of claim 80,

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

85. The method of claim 80,

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein a maximum current supplied from said battery is less than approximately 150 amperes.

86. The method of claim 80, wherein the at least one electric motor comprises a first electric motor and a second electric motor, the method further comprising:

operating a first alternating current-direct current (AC-DC) converter having an AC side coupled to the second electric motor, wherein said operating the first AC-DC converter comprises accepting AC or DC current and converting the current to DC or AC current respectively;

operating a second AC-DC converter coupled to a first electric motor, wherein said operating the second AC-DC converter comprises accepting AC current and converting the current to DC;

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein said battery is coupled to a DC side of said AC-DC converters;

storing DC energy received from said AC-DC converters and providing DC energy to at least said first AC-DC converter for providing power to at least said second electric motor; and

wherein a ratio of maximum DC voltage on the DC side of at least said first AC-DC converter coupled to said second electric motor to current supplied from said battery to at least said first AC-DC converter, when maximum current is so supplied, is at least 2.5.

87. The method of claim 86, wherein the maximum DC voltage on the DC side of either of said AC-DC converters is at least approximately 500 volts.

88. The method of claim 86, wherein the maximum DC current on the DC side of either of said AC-DC converters is less than approximately 150 amperes.

89. The method of claim 86, wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

90. The method of claim 86, wherein a maximum current supplied from said battery is less than approximately 150 amperes.

91. The method of claim 80, further comprising:

turning off the engine when the torque required to propel the vehicle is less than the SP.

92. The method of claim 80, further comprising:

turning off the engine when the torque required to propel the vehicle and/or charge the battery is less than the SP.

93. The method of claim 80, further comprising:

monitoring a state of charge of a battery comprised in the hybrid vehicle, wherein the battery is operable to;

store energy from the at least one electric motor and/or the engine; and

transmit energy to the at least one electric motor to propel the hybrid vehicle.

94. The method of claim 80, further comprising:

operating the engine to charge the battery when the state of charge of the battery indicates the need to do so, wherein the engine is operable to provide torque at least equal to the SP to propel the hybrid vehicle and to drive the at least one electric motor to charge the battery, wherein a first portion of the torque equal to RL is used to propel the hybrid vehicle, wherein a second portion of the torque in excess of RL is used to drive the at least one electric motor to charge the battery, and wherein said operating the engine to charge the battery comprises if the engine is not already running, starting the engine.

95. The method of claim 80, wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle and said operating both the at least one electric motor and the engine to propel the hybrid vehicle, each comprises:

if the engine is not already running, starting the engine.

96. The method of claim 80, further comprising:

monitoring the RL over time;

wherein said operating the at least one electric motor to propel the hybrid vehicle is performed when the RL<

the SP for at least a predetermined amount of time.

97. The method of claim 80, further comprising:

receiving operator input specifying a desired cruising speed;

controlling instantaneous engine torque output and operation of the at least one electric motor in accordance with variation in the RL to maintain the speed of the hybrid vehicle according to the desired cruising speed.

98. The method of claim 80, wherein the SP is at least approximately 30% of the MTO.

99. The method of claim 80,

wherein the hybrid vehicle is operated in a plurality of operating modes corresponding to values for the RL and the SP;

wherein said operating the at least one electric motor to drive the hybrid vehicle composes a low-load operation mode I;

wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle composes a high-way cruising operation mode IV; and

wherein said operating both the at least one electric motor and the engine to propel the hybrid vehicle composes an acceleration operation mode V.

100. The method of claim 99, wherein the engine can be operated in mode I without transmitting power to the wheels.

101. The method of claim 99, wherein the at least one electric motors comprises a first electric motor and a second electric motor, the method further comprising:

monitoring a state of charge of a battery comprised in the hybrid vehicle, wherein the battery is operable to store power from the engine and/or the at least one electric motor and transmit power to the at least one electric motor to propel the vehicle;

operating the engine to charge the battery when the state of charge of the battery is below a predetermined level and when the RL<

the SP, wherein said operating the engine to charge the battery composes a low-load battery charging mode II, and wherein said operating the engine to charge the battery comprises;

decoupling the engine from wheels of the hybrid vehicle; and

the engine providing torque at least equal to the SP to the first electric motor to charge the battery;

wherein during said operating the engine to charge the battery when the state of charge of the battery is below a predetermined level, the hybrid vehicle is propelled by torque provided by the second electric motor in response to energy supplied by the battery.

102. The method of claim 99, further comprising:

receiving operator input specifying a change in required torque to be applied to wheels of the hybrid vehicle; and

if the received operator input specifies a rapid increase in the required torque, changing operation from operating mode I directly to operating mode V.

103. The method of claim 99, wherein the hybrid vehicle further comprises a turbocharger controllably coupled to the engine, and wherein said operating both the engine and the at least one electric motor occurs when the RL>

the MTO for less than a predetermined time T, wherein the method further comprises;

operating the turbocharger to increase the MTO of the engine when desired, wherein said operating the turbocharger to increase the MTO of the engine occurs when the RL>

the MTO for more than the predetermined time T, and wherein said operating the turbocharger composes a turbocharged operation mode VI.

104. The method of claim 103, further comprising:

varying the time T responsive to the state of charge of the battery.

105. The method of claim 80, wherein the hybrid vehicle further comprises a turbocharger controllably coupled to the engine, wherein the method further comprises:

operating the turbocharger to increase the MTO of the engine when desired.

106. The method of claim 80, further comprising:

regeneratively charging a battery of the hybrid vehicle when instantaneous torque output of the engine>

the RL, when the RL is negative, and/or when braking is initiated by an operator of the hybrid vehicle.

107. The method of claim 80, wherein the hybrid vehicle comprises a variable-ratio transmission disposed between the engine and the wheels of the hybrid vehicle.

108. The method of claim 107, wherein said variable-ratio transmission comprises a planetary gear mechanism.

109. The method of claim 80, wherein the engine is controllably coupled to one or more wheels of the hybrid vehicle by a clutch.

110. The method of claim 80, further comprising:

controlling the engine such that combustion of fuel within the engine occurs substantially at a stoichiometric ratio, wherein said controlling the engine comprises limiting a rate of change of torque output of the engine; and

if the engine is incapable of supplying instantaneous torque required to propel the hybrid vehicle, supplying additional torque from the at least one electric motor.

111. The method of claim 80, further comprising:

rotating the engine before starting the engine such that its cylinders are heated by compression of air therein.

112. The method of claim 80, further comprising:

operating the engine at torque output levels less than the SP under abnormal and transient conditions to satisfy drivability and/or safety considerations.

113. The method of claim 80, wherein the second electric motor is sufficiently powerful to provide acceleration of said vehicle sufficient to conform to the Federal urban cycle driving fuel mileage test without use of torque from the engine to propel the vehicle.

114. A method for controlling a hybrid vehicle, comprising:

determining instantaneous road load (RL) required to propel the hybrid vehicle responsive to an operator command;

monitoring the RL over time;

operating at least one electric motor to propel the hybrid vehicle when the RL required to do so is less than a setpoint (SP);

wherein said operating the at least one electric motor to propel the hybrid vehicle is performed when the RL<

the SP for at least a predetermined amount of time;

operating an internal combustion engine of the hybrid vehicle to propel the hybrid vehicle when the RL required to do so is between the SP and a maximum torque output (MTO) of the engine, wherein the engine is operable to efficiently produce torque above the SP, and wherein the SP is substantially less than the MTO; and

operating both the at least one electric motor and the engine to propel the hybrid vehicle when the torque RL required to do so is more than the MTO.

115. The method of claim 114,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a ratio of maximum DC voltage to maximum current supplied is at least 2.5.

116. The method of claim 115, wherein the maximum DC voltage is at least approximately 500 volts.

117. The method of claim 115, wherein the maximum current is less than approximately 150 amperes.

118. The method of claim 114,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

119. The method of claim 114,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a maximum current supplied from said battery is less than approximately 150 amperes.

120. The method of claim 114, wherein the at least one electric motor comprises a first electric motor and a second electric motor, the method further comprising:

operating a first alternating current-direct current (AC-DC) converter having an AC side coupled to the second electric motor, wherein said operating the first AC-DC converter comprises accepting AC or DC current and converting the current to DC or AC current respectively;

operating a second AC-DC converter coupled to a first electric motor, wherein said operating the second AC-DC converter comprises accepting AC current and converting the current to DC;

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein said battery is coupled to a DC side of said AC-DC converters;

storing DC energy received from said AC-DC converters and providing DC energy to at least said first AC-DC converter for providing power to at least said second electric motor; and

wherein a ratio of maximum DC voltage on the DC side of at least said first AC-DC converter coupled to said second electric motor to current supplied from said battery to at least said first AC-DC converter, when maximum current is so supplied, is at least 2.5.

121. The method of claim 120, wherein the maximum DC voltage on the DC side of either of said AC-DC converters is at least approximately 500 volts.

122. The method of claim 120, wherein the maximum DC current on the DC side of either of said AC-DC converters is less than approximately 150 amperes.

123. The method of claim 120, wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

124. The method of claim 120, wherein a maximum current supplied from said battery is less than approximately 150 amperes.

125. The method of claim 114, further comprising:

turning off the engine when the torque required to propel the vehicle is less than the SP.

126. The method of claim 114, further comprising:

turning off the engine when the torque required to propel the vehicle and/or charge the battery is less than the SP.

127. The method of claim 114, further comprising:

monitoring a state of charge of a battery comprised in the hybrid vehicle, wherein the battery is operable to;

store energy from the at least one electric motor and/or the engine; and

transmit energy to the at least one electric motor to propel the hybrid vehicle.

128. The method of claim 114, further comprising:

operating the engine to charge the battery when the state of charge of the battery indicates the need to do so, wherein the engine is operable to provide torque at least equal to the SP to propel the hybrid vehicle and to drive the at least one electric motor to charge the battery, wherein a first portion of the torque equal to RL is used to propel the hybrid vehicle, wherein a second portion of the torque in excess of RL is used to drive the at least one electric motor to charge the battery, and wherein said operating the engine to charge the battery comprises if the engine is not already running, starting the engine.

129. The method of claim 114, wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle and said operating both the at least one electric motor and the engine to propel the hybrid vehicle, each comprises:

if the engine is not already running, starting the engine.

130. The method of claim 114, further comprising:

receiving operator input specifying a desired cruising speed;

controlling instantaneous engine torque output and operation of the at least one electric motor in accordance with variation in the RL to maintain the speed of the hybrid vehicle according to the desired cruising speed.

131. The method of claim 114, wherein the SP is at least approximately 30% of the MTO.

132. The method of claim 114,

wherein the hybrid vehicle is operated in a plurality of operating modes corresponding to values for the RL and the SP;

wherein said operating the at least one electric motor to drive the hybrid vehicle composes a low-load operation mode I;

wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle composes a high-way cruising operation mode IV; and

wherein said operating both the at least one electric motor and the engine to propel the hybrid vehicle composes an acceleration operation mode V.

133. The method of claim 132, wherein the engine can be operated without transfer of power to wheels of the hybrid vehicle in mode I.

134. The method of claim 132, wherein the at least one electric motors comprises a first electric motor and a second electric motor, the method further comprising:

monitoring a state of charge of a battery comprised in the hybrid vehicle, wherein the battery is operable to store energy from the engine and/or the at least one electric motor and transmit energy to the at least one electric motor to propel the vehicle;

operating the engine to charge the battery when the state of charge of the battery is below a predetermined level and when the RL<

the SP, wherein said operating the engine to charge the battery composes a low-load battery charging mode II, and wherein said operating the engine to charge the battery comprises;

decoupling the engine from wheels of the hybrid vehicle; and

the engine providing torque at least equal to the SP to the first electric motor to charge the battery;

wherein during said operating the engine to charge the battery when the state of charge of the battery is below a predetermined level, the hybrid vehicle is propelled by torque provided by the second electric motor in response to energy supplied by the battery.

135. The method of claim 132, further comprising:

receiving operator input specifying a change in required torque to be applied to wheels of the hybrid vehicle; and

if the received operator input specifies a rapid increase in the required torque, changing operation from operating mode I directly to operating mode V.

136. The method of claim 132, wherein the hybrid vehicle further comprises a turbocharger controllably coupled to the engine, and wherein said operating both the engine and the at least one electric motor occurs when the RL>

the MTO for less than a predetermined time T, wherein the method further comprises;

operating the turbocharger to increase the MTO of the engine when desired, wherein said operating the turbocharger to increase the MTO of the engine occurs when the RL>

the MTO for more than the predetermined time T, and wherein said operating the turbocharger composes a turbocharged operation mode VI.

137. The method of claim 136, further comprising:

varying the time T responsive to the state of charge of the battery.

138. The method of claim 114, wherein the hybrid vehicle further comprises a turbocharger controllably coupled to the engine, wherein the method further comprises:

operating the turbocharger to increase the MTO of the engine when desired.

139. The method of claim 114, further comprising:

regeneratively charging a battery of the hybrid vehicle when instantaneous torque output of the engine>

the RL, when the RL is negative, and/or when braking is initiated by an operator of the hybrid vehicle.

140. The method of claim 114, wherein the hybrid vehicle comprises a variable-ratio transmission disposed between the engine and the wheels of the hybrid vehicle.

141. The method of claim 140, wherein said variable-ratio transmission comprises a planetary gear mechanism.

142. The method of claim 114, wherein the engine is controllably coupled to one or more wheels of the hybrid vehicle by a clutch.

143. The method of claim 114, further comprising:

controlling the engine such that combustion of fuel within the engine occurs substantially at a stoichiometric ratio, wherein said controlling the engine comprises limiting a rate of change of torque output of the engine; and

if the engine is incapable of supplying instantaneous torque required to propel the hybrid vehicle, supplying additional torque from the at least one electric motor.

144. The method of claim 114, further comprising:

rotating the engine before starting the engine such that its cylinders are heated by compression of air therein.

145. The method of claim 114, further comprising:

operating the engine at torque output levels less than the SP under abnormal and transient conditions to satisfy drivability and/or safety considerations.

146. The method of claim 114, wherein the at least one electric motor is sufficiently powerful to provide acceleration of said vehicle sufficient to conform to the Federal urban cycle driving fuel mileage test without use of torque from the engine to propel the vehicle.

147. A method for controlling a hybrid vehicle, comprising:

determining instantaneous road load (RL) required to propel the hybrid vehicle responsive to an operator command;

wherein the hybrid vehicle is operated in a plurality of operating modes corresponding to values for the RL and a setpoint (SP);

operating at least one first electric motor to propel the hybrid vehicle when the RL required to do so is less than the SP;

wherein said operating the at least one first electric motor to drive the hybrid vehicle comprises a low-load operation mode I;

operating an internal combustion engine of the hybrid vehicle to propel the hybrid vehicle when the RL required to do so is between the SP and a maximum torque output (MTO) of the engine, wherein the engine is operable to efficiently produce torque above the SP, and wherein the SP is substantially less than the MTO;

wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle comprises a highway cruising operation mode IV;

operating both the at least one first electric motor and the engine to propel the hybrid vehicle when the torque RL required to do so is more than the MTO;

wherein said operating both the at least one first electric motor and the engine to propel the hybrid vehicle comprises an acceleration operation mode V;

monitoring a state of charge of a battery comprised in the hybrid vehicle, wherein the battery is operable to store power from the engine and/or the at least one first electric motor and transmit power to the at least one first electric motor to propel the vehicle; and

operating the engine to charge the battery when the state of charge of the battery is below a predetermined level and when the RL<

the SP, wherein said operating the engine to charge the battery comprises a low-load battery charging mode II, and wherein said operating the engine to charge the battery comprises;

operating the engine without transferring power to the wheels of the hybrid vehicle; and

the engine providing torque at least equal to the SP to the at least one first electric motor to charge the battery;

wherein during said operating the engine to charge the battery when the state of charge of the battery is below a predetermined level, the hybrid vehicle is propelled by torque provided by at least one second electric motor in response to energy supplied by the battery.

148. The method of claim 147,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a ratio of maximum DC voltage to maximum current supplied is at least 2.5.

149. The method of claim 148, wherein the maximum DC voltage is at least approximately 500 volts.

150. The method of claim 148, wherein the maximum current is less than approximately 150 amperes.

151. The method of claim 147,

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

152. The method of claim 147,

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein a maximum current supplied from said battery is less than approximately 150 amperes.

153. The method of claim 147, wherein the at least one electric motor comprises a first electric motor and a second electric motor, the method further comprising:

operating a first alternating current-direct current (AC-DC) converter having an AC side coupled to the second electric motor, wherein said operating the first AC-DC converter comprises accepting AC or DC current and converting the current to DC or AC current respectively;

operating a second AC-DC converter coupled to a first electric motor, wherein said operating the second AC-DC converter comprises accepting AC current and converting the current to DC;

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein said battery is coupled to a DC side of said AC-DC converters;

storing DC energy received from said AC-DC converters and providing DC energy to at least said first AC-DC converter for providing power to at least said second electric motor; and

wherein a ratio of maximum DC voltage on the DC side of at least said first AC-DC converter coupled to said second electric motor to current supplied from said battery to at least said first AC-DC converter, when maximum current is so supplied, is at least 2.5.

154. The method of claim 153, wherein the maximum DC voltage on the DC side of either of said AC-DC converters is at least approximately 500 volts.

155. The method of claim 153, wherein the maximum DC current on the DC side of either of said AC-DC converters is less than approximately 150 amperes.

156. The method of claim 153, wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

157. The method of claim 153, wherein a maximum current supplied from said battery is less than approximately 150 amperes.

158. The method of claim 147, wherein the engine can be operated without transferring power to the wheels of the hybrid vehicle during operation in mode I.

159. The method of claim 147, further comprising:

receiving operator input specifying a change in required torque to be applied to wheels of the hybrid vehicle; and

if the received operator input specifies a rapid increase in the required torque, changing operation from operating mode I directly to operating mode V.

160. The method of claim 147, wherein the at least one electric motor is sufficiently powerful to provide acceleration of said vehicle sufficient to conform to the Federal urban cycle driving fuel mileage test without use of torque from the engine to propel the vehicle.

161. A method for controlling a hybrid vehicle, comprising:

determining instantaneous road load (RL) required to propel the hybrid vehicle responsive to an operator command;

wherein the hybrid vehicle is operated in a plurality of operating modes corresponding to values for the RL and a setpoint (SP);

operating at least one first electric motor to propel the hybrid vehicle when the RL required to do so is less than the SP;

wherein said operating the at least one first electric motor to drive the hybrid vehicle composes a low-load operation mode I;

operating an internal combustion engine of the hybrid vehicle to propel the hybrid vehicle when the RL required to do so is between the SP and a maximum torque output (MTO) of the engine, wherein the engine is operable to efficiently produce torque above the SP, and wherein the SP is substantially less than the MTO;

wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle composes a high-way cruising operation mode IV;

operating both the at least one first electric motor and the engine to propel the hybrid vehicle when the torque RL required to do so is more than the MTO;

wherein said operating both the at least one first electric motor and the engine to propel the hybrid vehicle composes an acceleration operation mode V;

receiving operator input specifying a change in required torque to be applied to wheels of the hybrid vehicle; and

if the received operator input specifies a rapid increase in the required torque, changing operation from operating mode I directly to operating mode V.

162. The method of claim 161,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a ratio of maximum DC voltage to maximum current supplied is at least 2.5.

163. The method of claim 161, wherein the maximum DC voltage is at least approximately 500 volts.

164. The method of claim 161, wherein the maximum current is less than approximately 150 amperes.

165. The method of claim 161,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

166. The method of claim 161,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a maximum current supplied from said battery is less than approximately 150 amperes.

167. The method of claim 161, wherein the at least one electric motor comprises a first electric motor and a second electric motor, the method further comprising:

operating a first alternating current-direct current (AC-DC) converter having an AC side coupled to the second electric motor, wherein said operating the first AC-DC converter comprises accepting AC or DC current and converting the current to DC or AC current respectively;

operating a second AC-DC converter coupled to a first electric motor, wherein said operating the second AC-DC converter comprises accepting AC current and converting the current to DC;

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein said battery is coupled to a DC side of said AC-DC converters;

storing DC energy received from said AC-DC converters and providing DC energy to at least said first AC-DC converter for providing power to at least said second electric motor; and

wherein a ratio of maximum DC voltage on the DC side of at least said first AC-DC converter coupled to said second electric motor to current supplied from said battery to at least said first AC-DC converter, when maximum current is so supplied, is at least 2.5.

168. The method of claim 167, wherein the maximum DC voltage on the DC side of either of said AC-DC converters is at least approximately 500 volts.

169. The method of claim 167, wherein the maximum DC current on the DC side of either of said AC-DC converters is less than approximately 150 amperes.

170. The method of claim 167, wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

171. The method of claim 167, wherein a maximum current supplied from said battery is less than approximately 150 amperes.

172. The method of claim 161, wherein said engine can be operated without transmitting power to the wheels of the hybrid vehicle during operation in mode I.

173. The method of claim 161, wherein said at least one electric motor is sufficiently powerful to provide acceleration of said vehicle sufficient to conform to the Federal urban cycle driving fuel mileage test without use of torque from the engine to propel the vehicle.

174. A method for controlling a hybrid vehicle, comprising:

determining instantaneous road load (RL) required to propel the hybrid vehicle responsive to an operator command;

wherein the hybrid vehicle is operated in a plurality of operating modes corresponding to values for the RL and a setpoint (SP);

operating at least one first electric motor to propel the hybrid vehicle when the RL required to do so is less than the SP;

wherein said operating the at least one first electric motor to drive the hybrid vehicle composes a low-load operation mode I;

operating an internal combustion engine of the hybrid vehicle to propel the hybrid vehicle when the RL required to do so is between the SP and a maximum torque output (MTO) of the engine, wherein the engine is operable to efficiently produce torque above the SP, and wherein the SP is substantially less than the MTO;

wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle composes a high-way cruising operation mode IV;

operating both the at least one first electric motor and the engine to propel the hybrid vehicle when the torque RL required to do so is more than the MTO;

wherein said operating both the at least one first electric motor and the engine to propel the hybrid vehicle composes an acceleration operation mode V, and wherein said operating both the engine and the at least one electric motor occurs when the RL>

the MTO for less than a predetermined time T; and

operating a turbocharger controllably coupled to the engine to increase the MTO of the engine when desired, wherein said operating the turbocharger to increase the MTO of the engine occurs when the RL>

the MTO for more than the predetermined time T, and wherein said operating the turbocharger composes a turbocharged operation mode VI.

175. The method of claim 174,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a ratio of maximum DC voltage to maximum current supplied is at least 2.5.

176. The method of claim 174, wherein the maximum DC voltage is at least approximately 500 volts.

177. The method of claim 174, wherein the maximum current is less than approximately 150 amperes.

178. The method of claim 174,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

179. The method of claim 174,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a maximum current supplied from said battery is less than approximately 150 amperes.

180. The method of claim 174, wherein the at least one electric motor comprises a first electric motor and a second electric motor, the method further comprising:

operating a first alternating current-direct current (AC-DC) converter having an AC side coupled to the second electric motor, wherein said operating the first AC-DC converter comprises accepting AC or DC current and converting the current to DC or AC current respectively;

operating a second AC-DC converter coupled to a first electric motor, wherein said operating the second AC-DC converter comprises accepting AC current and converting the current to DC;

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein said battery is coupled to a DC side of said AC-DC converters;

storing DC energy received from said AC-DC converters and providing DC energy to at least said first AC-DC converter for providing power to at least said second electric motor; and

wherein a ratio of maximum DC voltage on the DC side of at least said first AC-DC converter coupled to said second electric motor to current supplied from said battery to at least said first AC-DC converter, when maximum current is so supplied, is at least 2.5.

181. The method of claim 180, wherein the maximum DC voltage on the DC side of either of said AC-DC converters is at least approximately 500 volts.

182. The method of claim 180, wherein the maximum DC current on the DC side of either of said AC-DC converters is less than approximately 150 amperes.

183. The method of claim 180, wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

184. The hybrid vehicle of claim 180, wherein a maximum current supplied from said battery is less than approximately 150 amperes.

185. The method of claim 174, wherein the engine can be operated without transfer of power to the wheels of the hybrid vehicle during operation in mode I.

186. The method of claim 174, further comprising:

varying the time T responsive to the state of charge of the battery.

187. The method of claim 174, wherein the at least one first electric motor is sufficiently powerful to provide acceleration of said vehicle sufficient to conform to the Federal urban cycle driving fuel mileage test without use of torque from the engine to propel the vehicle.

188. A method for controlling a hybrid vehicle, comprising:

determining instantaneous road load (RL) required to propel the hybrid vehicle responsive to an operator command;

operating at least one electric motor to propel the hybrid vehicle when the RL required to do so is less than a setpoint (SP);

operating an internal combustion engine of the hybrid vehicle to propel the hybrid vehicle when the RL required to do so is between the SP and a maximum torque output (MTO) of the engine, wherein the engine is operable to efficiently produce torque above the SP, and wherein the SP is substantially less than the MTO; and

operating both the at least one electric motor and the engine to propel the hybrid vehicle when the torque RL required to do so is more than the MTO; and

operating a turbocharger controllably coupled to the engine to increase the MTO of the engine when desired.

189. The method of claim 188,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a ratio of maximum DC voltage to maximum current supplied is at least 2.5.

190. The method of claim 189, wherein the maximum DC voltage is at least approximately 500 volts.

191. The method of claim 189, wherein the maximum current is less than approximately 150 amperes.

192. The method of claim 188,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

193. The method of claim 188,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a maximum current supplied from said battery is less than approximately 150 amperes.

194. The method of claim 188, wherein the at least one electric motor comprises a first electric motor and a second electric motor, the method further comprising:

operating a first alternating current-direct current (AC-DC) converter having an AC side coupled to the second electric motor, wherein said operating the first AC-DC converter comprises accepting AC or DC current and converting the current to DC or AC current respectively;

operating a second AC-DC converter coupled to a first electric motor, wherein said operating the second AC-DC converter comprises accepting AC current and converting the current to DC;

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein said battery is coupled to a DC side of said AC-DC converters;

storing DC energy received from said AC-DC converters and providing DC energy to at least said first AC-DC converter for providing power to at least said second electric motor; and

wherein a ratio of maximum DC voltage on the DC side of at least said first AC-DC converter coupled to said second electric motor to current supplied from said battery to at least said first AC-DC converter, when maximum current is so supplied, is at least 2.5.

195. The method of claim 194, wherein the maximum DC voltage on the DC side of either of said AC-DC converters is at least approximately 500 volts.

196. The method of claim 194, wherein the maximum DC current on the DC side of either of said AC-DC converters is less than approximately 150 amperes.

197. The method of claim 194, wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

198. The method of claim 194, wherein a maximum current supplied from said battery is less than approximately 150 amperes.

199. The method of claim 188, further comprising:

turning off the engine when the torque required to propel the vehicle is less than the SP.

200. The method of claim 188, further comprising:

turning off the engine when the torque required to propel the vehicle and/or charge the battery is less than the SP.

201. The method of claim 188, further comprising:

monitoring a state of charge of a battery comprised in the hybrid vehicle, wherein the battery is operable to;

store power from the at least one electric motor and/or the engine; and

transmit power to the at least one electric motor to propel the hybrid vehicle.

202. The method of claim 188, further comprising:

operating the engine to charge the battery when the state of charge of the battery indicates the need to do so, wherein the engine is operable to provide torque at least equal to the SP to propel the hybrid vehicle and to drive the at least one electric motor to charge the battery, wherein a first portion of the torque equal to RL is used to propel the hybrid vehicle, wherein a second portion of the torque in excess of RL is used to drive the at least one electric motor to charge the battery, and wherein said operating the engine to charge the battery comprises if the engine is not already running, starting the engine.

203. The method of claim 188, wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle and said operating both the at least one electric motor and the engine to propel the hybrid vehicle, each comprises:

if the engine is not already running, starting the engine.

204. The method of claim 188, further comprising:

receiving operator input specifying a desired cruising speed;

controlling instantaneous engine torque output and operation of the at least one electric motor in accordance with variation in the RL to maintain the speed of the hybrid vehicle according to the desired cruising speed.

205. The method of claim 188, wherein the SP is at least approximately 30% of the MTO.

206. The method of claim 188,

wherein the hybrid vehicle is operated in a plurality of operating modes corresponding to values for the RL and the SP;

wherein said operating the at least one electric motor to drive the hybrid vehicle composes a low-load operation mode I;

wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle composes a high-way cruising operation mode IV; and

wherein said operating both the at least one electric motor and the engine to propel the hybrid vehicle composes an acceleration operation mode V.

207. The method of claim 188, wherein the engine can be operated without transfer of power to the wheels of the hybrid vehicle during operation in mode I.

208. The method of claim 188, further comprising:

regeneratively charging a battery of the hybrid vehicle when instantaneous torque output of the engine>

the RL, when the RL is negative, and/or when braking is initiated by an operator of the hybrid vehicle.

209. The method of claim 188, wherein the hybrid vehicle comprises a variable-ratio transmission disposed between the engine and the wheels of the hybrid vehicle.

210. The method of claim 209, wherein said variable-ratio transmission comprises a planetary gear mechanism.

211. The method of claim 188, wherein the engine is controllably coupled to one or more wheels of the hybrid vehicle by a clutch.

212. The method of claim 188, further comprising:

rotating the engine before starting the engine such that its cylinders are heated by compression of air therein.

213. The method of claim 188, further comprising:

operating the engine at torque output levels less than the SP under abnormal and transient conditions to satisfy drivability and/or safety considerations.

214. The method of claim 188, wherein at least one electric motor is sufficiently powerful to provide acceleration of said vehicle sufficient to conform to the Federal urban cycle driving fuel mileage test without use of torque from the engine to propel the vehicle.

215. A method for controlling a hybrid vehicle, comprising:

determining instantaneous road load (RL) required to propel the hybrid vehicle responsive to an operator command;

operating at least one electric motor to propel the hybrid vehicle when the RL required to do so is less than a setpoint (SP);

operating an internal combustion engine of the hybrid vehicle to propel the hybrid vehicle when the RL required to do so is between the SP and a maximum torque output (MTO) of the engine, wherein the engine is operable to efficiently produce torque above the SP, and wherein the SP is substantially less than the MTO; and

operating both the at least one electric motor and the engine to propel the hybrid vehicle when the torque RL required to do so is more than the MTO; and

regeneratively charging a battery of the hybrid vehicle when instantaneous torque output of the engine>

the RL, when the RL is negative, and/or when braking is initiated by an operator of the hybrid vehicle.

216. The method of claim 215,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a ratio of maximum DC voltage to maximum current supplied is at least 2.5.

217. The method of claim 216, wherein the maximum DC voltage is at least approximately 500 volts.

218. The method of claim 216, wherein the maximum current is less than approximately 150 amperes.

219. The method of claim 215,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

220. The method of claim 215,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a maximum current supplied from said battery is less than approximately 150 amperes.

221. The method of claim 215, wherein the at least one electric motor comprises a first electric motor and a second electric motor, the method further comprising:

operating a first alternating current-direct current (AC-DC) converter having an AC side coupled to the second electric motor, wherein said operating the first AC-DC converter comprises accepting AC or DC current and converting the current to DC or AC current respectively;

operating a second AC-DC converter coupled to a first electric motor, wherein said operating the second AC-DC converter comprises accepting AC current and converting the current to DC;

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein said battery is coupled to a DC side of said AC-DC converters;

storing DC energy received from said AC-DC converters and providing DC energy to at least said first AC-DC converter for providing power to at least said second electric motor; and

wherein a ratio of maximum DC voltage on the DC side of at least said first AC-DC converter coupled to said second electric motor to current supplied from said battery to at least said first AC-DC converter, when maximum current is so supplied, is at least 2.5.

222. The method of claim 221, wherein the maximum DC voltage on the DC side of either of said AC-DC converters is at least approximately 500 volts.

223. The method of claim 221, wherein the maximum DC current on the DC side of either of said AC-DC converters is less than approximately 150 amperes.

224. The method of claim 221, wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

225. The hybrid vehicle of claim 221, wherein a maximum current supplied from said battery is less than approximately 150 amperes.

226. The method of claim 215, further comprising:

turning off the engine when the torque required to propel the vehicle is less than the SP.

227. The method of claim 215, further comprising:

turning off the engine when the torque required to propel the vehicle and/or charge the battery is less than the SP.

228. The method of claim 215, further comprising:

monitoring a state of charge of a battery comprised in the hybrid vehicle, wherein the battery is operable to;

store energy from the at least one electric motor and/or the engine; and

transmit energy to the at least one electric motor to propel the hybrid vehicle.

229. The method of claim 215, further comprising:

operating the engine to charge the battery when the state of charge of the battery indicates the need to do so, wherein the engine is operable to provide torque at least equal to the SP to propel the hybrid vehicle and to drive the at least one electric motor to charge the battery, wherein a first portion of the torque equal to RL is used to propel the hybrid vehicle, wherein a second portion of the torque in excess of RL is used to drive the at least one electric motor to charge the battery, and wherein said operating the engine to charge the battery comprises if the engine is not already running, starting the engine.

230. The method of claim 215, wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle and said operating both the at least one electric motor and the engine to propel the hybrid vehicle, each comprises:

if the engine is not already running, starting the engine.

231. The method of claim 215, further comprising:

receiving operator input specifying a desired cruising speed;

controlling instantaneous engine torque output and operation of the at least one electric motor in accordance with variation in the RL to maintain the speed of the hybrid vehicle according to the desired cruising speed.

232. The method of claim 215, wherein the SP is at least approximately 30% of the MTO.

233. The method of claim 215,

wherein the hybrid vehicle is operated in a plurality of operating modes corresponding to values for the RL and the SP;

wherein said operating the at least one electric motor to drive the hybrid vehicle composes a low-load operation mode I;

wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle composes a high-way cruising operation mode IV; and

wherein said operating both the at least one electric motor and the engine to propel the hybrid vehicle composes an acceleration operation mode V.

234. The method of claim 215, wherein the engine can be operated without transfer of power to the wheels of the hybrid vehicle during operation in mode I.

235. The method of claim 215, wherein the hybrid vehicle comprises a variable-ratio transmission disposed between the engine and the wheels of the hybrid vehicle.

236. The method of claim 235, wherein said variable-ratio transmission comprises a planetary gearbox.

237. The method of claim 215, wherein the engine is controllably coupled to one or more wheels of the hybrid vehicle by a clutch.

238. The method of claim 215, further comprising:

rotating the engine before starting the engine such that its cylinders are heated by compression of air therein.

239. The method of claim 215, further comprising:

operating the engine at torque output levels less than the SP under abnormal and transient conditions to satisfy drivability and/or safety considerations.

240. The method of claim 215, wherein the at least one electric motor is sufficiently powerful to provide acceleration of said vehicle sufficient to conform to the Federal urban cycle driving fuel mileage test without use of torque from the engine to propel the vehicle.

241. A method for controlling a hybrid vehicle, comprising:

determining instantaneous road load (RL) required to propel the hybrid vehicle responsive to an operator command;

operating at least one electric motor to propel the hybrid vehicle when the RL required to do so is less than a setpoint (SP);

operating an internal combustion engine of the hybrid vehicle to propel the hybrid vehicle when the RL required to do so is between the SP and a maximum torque output (MTO) of the engine, wherein the engine is operable to efficiently produce torque above the SP, and wherein the SP is substantially less than the MTO; and

operating both the at least one electric motor and the engine to propel the hybrid vehicle when the torque RL required to do so is more than the MTO;

controlling said engine such that combustion of fuel within the engine occurs substantially at a stoichiometric ratio, wherein said controlling the engine comprises limiting a rate of change of torque output of the engine; and

if the engine is incapable of supplying instantaneous torque required to propel the hybrid vehicle, supplying additional torque from the at least one electric motor.

242. The method of claim 241,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a ratio of maximum DC voltage to maximum current supplied is at least 2.5.

243. The method of claim 242, wherein the maximum DC voltage is at least approximately 500 volts.

244. The method of claim 242, wherein the maximum current is less than approximately 150 amperes.

245. The method of claim 241,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

246. The method of claim 241,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a maximum current supplied from said battery is less than approximately 150 amperes.

247. The method of claim 241, wherein the at least one electric motor comprises a first electric motor and a second electric motor, the method further comprising:

operating a first alternating current-direct current (AC-DC) converter having an AC side coupled to the second electric motor, wherein said operating the first AC-DC converter comprises accepting AC or DC current and converting the current to DC or AC current respectively;

operating a second AC-DC converter coupled to a first electric motor, wherein said operating the second AC-DC converter comprises accepting AC current and converting the current to DC;

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein said battery is coupled to a DC side of said AC-DC converters;

storing DC energy received from said AC-DC converters and providing DC energy to at least said first AC-DC converter for providing power to at least said second electric motor; and

wherein a ratio of maximum DC voltage on the DC side of at least said first AC-DC converter coupled to said second electric motor to current supplied from said battery to at least said first AC-DC converter, when maximum current is so supplied, is at least 2.5.

248. The method of claim 247, wherein the maximum DC voltage on the DC side of either of said AC-DC converters is at least approximately 500 volts.

249. The method of claim 247, wherein the maximum DC current on the DC side of either of said AC-DC converters is less than approximately 150 amperes.

250. The method of claim 247, wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

251. The method of claim 247, wherein a maximum current supplied from said battery is less than approximately 150 amperes.

252. The method of claim 241, further comprising:

turning off the engine when the torque required to propel the vehicle is less than the SP.

253. The method of claim 241, further comprising:

turning off the engine when the torque required to propel the vehicle and/or charge the battery is less than the SP.

254. The method of claim 241, further comprising:

monitoring a state of charge of a battery comprised in the hybrid vehicle, wherein the battery is operable to;

store energy from the at least one electric motor and/or the engine; and

transmit energy to the at least one electric motor to propel the hybrid vehicle.

255. The method of claim 241, further comprising:

operating the engine to charge the battery when the state of charge of the battery indicates the need to do so, wherein the engine is operable to provide torque at least equal to the SP to propel the hybrid vehicle and to drive the at least one electric motor to charge the battery, wherein a first portion of the torque equal to RL is used to propel the hybrid vehicle, wherein a second portion of the torque in excess of RL is used to drive the at least one electric motor to charge the battery, and wherein said operating the engine to charge the battery comprises if the engine is not already running, starting the engine.

256. The method of claim 241, wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle and said operating both the at least one electric motor and the engine to propel the hybrid vehicle, each comprises:

if the engine is not already running, starting the engine.

257. The method of claim 241, further comprising:

receiving operator input specifying a desired cruising speed;

controlling instantaneous engine torque output and operation of the at least one electric motor in accordance with variation in the RL to maintain the speed of the hybrid vehicle according to the desired cruising speed.

258. The method of claim 241, wherein the SP is at least approximately 30% of the MTO.

259. The method of claim 241,

wherein the hybrid vehicle is operated in a plurality of operating modes corresponding to values for the RL and the SP;

wherein said operating the at least one electric motor to drive the hybrid vehicle composes a low-load operation mode I;

wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle composes a high-way cruising operation mode IV; and

wherein said operating both the at least one electric motor and the engine to propel the hybrid vehicle composes an acceleration operation mode V.

260. The method of claim 241, wherein the engine can be operated without transfer of power to the wheels of the hybrid vehicle during operation in mode I.

261. The method of claim 241, wherein the hybrid vehicle comprises a variable-ratio transmission disposed between the engine and the wheels of the hybrid vehicle.

262. The method of claim 261, wherein said variable-ratio transmission comprises a planetary gear mechanism.

263. The method of claim 241, wherein the engine is controllably coupled to one or more wheels of the hybrid vehicle by a clutch.

264. The method of claim 241, further comprising:

rotating the engine before starting the engine such that its cylinders are heated by compression of air therein.

265. The method of claim 241, further comprising:

operating the engine at torque output levels less than the SP under abnormal and transient conditions to satisfy drivability and/or safety considerations.

266. The method of claim 241, wherein the at least one electric motor is sufficiently powerful to provide acceleration of said vehicle sufficient to conform to the Federal urban cycle driving fuel mileage test without use of torque from the engine to propel the vehicle.

267. A method for controlling a hybrid vehicle, comprising:

determining instantaneous road load (RL) required to propel the hybrid vehicle responsive to an operator command;

operating at least one electric motor to propel the hybrid vehicle when the RL required to do so is less than a setpoint (SP);

operating an internal combustion engine of the hybrid vehicle to propel the hybrid vehicle when the RL required to do so is between the SP and a maximum torque output (MTO) of the engine, wherein the engine is operable to efficiently produce torque above the SP, and wherein the SP is substantially less than the MTO;

operating both the at least one electric motor and the engine to propel the hybrid vehicle when the torque RL required to do so is more than the MTO; and

rotating the engine before starting the engine such that its cylinders are heated by compression of air therein.

268. The method of claim 267,

wherein said operating the at least one electric motor comprises supplying energy from a battery;

wherein a ratio of maximum DC voltage to maximum current supplied is at least 2.5.

269. The method of claim 268, wherein the maximum DC voltage is at least approximately 500 volts.

270. The method of claim 268, wherein the maximum current is less than approximately 150 amperes.

271. The method of claim 267,

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

272. The method of claim 267,

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein a maximum current supplied from said battery is less than approximately 150 amperes.

273. The method of claim 267, wherein the at least one electric motor comprises a first electric motor and a second electric motor, the method further comprising:

operating a first alternating current-direct current (AC-DC) converter having an AC side coupled to the second electric motor, wherein said operating the first AC-DC converter comprises accepting AC or DC current and converting the current to DC or AC current respectively;

operating a second AC-DC converter coupled to a first electric motor, wherein said operating the second AC-DC converter comprises accepting AC current and converting the current to DC;

wherein said operating the at least one electric motor comprises supplying power from a battery;

wherein said battery is coupled to a DC side of said AC-DC converters;

storing DC energy received from said AC-DC converters and providing DC energy to at least said first AC-DC converter for providing power to at least said second electric motor; and

wherein a ratio of maximum DC voltage on the DC side of at least said first AC-DC converter coupled to said second electric motor to current supplied from said battery to at least said first AC-DC converter, when maximum current is so supplied, is at least 2.5.

274. The method of claim 273, wherein the maximum DC voltage on the DC side of either of said AC-DC converters is at least approximately 500 volts.

275. The method of claim 273, wherein the maximum DC current on the DC side of either of said AC-DC converters is less than approximately 150 amperes.

276. The method of claim 273, wherein a maximum DC voltage supplied from said battery is at least approximately 500 volts.

277. The method of claim 273, wherein a maximum current supplied from said battery is less than approximately 150 amperes.

278. The method of claim 267, further comprising:

turning off the engine when the torque required to propel the vehicle is less than the SP.

279. The method of claim 267, further comprising:

turning off the engine when the torque required to propel the vehicle and/or charge the battery is less than the SP.

280. The method of claim 267, further comprising:

monitoring a state of charge of a battery comprised in the hybrid vehicle, wherein the battery is operable to;

store energy from the at least one electric motor and/or the engine; and

transmit energy to the at least one electric motor to propel the hybrid vehicle.

281. The method of claim 267, further comprising:

operating the engine to charge the battery when the state of charge of the battery indicates the need to do so, wherein the engine is operable to provide torque at least equal to the SP to propel the hybrid vehicle and to drive the at least one electric motor to charge the battery, wherein a first portion of the torque equal to RL is used to propel the hybrid vehicle, wherein a second portion of the torque in excess of RL is used to drive the at least one electric motor to charge the battery, and wherein said operating the engine to charge the battery comprises if the engine is not already running, starting the engine.

282. The method of claim 267, wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle and said operating both the at least one electric motor and the engine to propel the hybrid vehicle, each comprises:

if the engine is not already running, starting the engine.

283. The method of claim 267, further comprising:

receiving operator input specifying a desired cruising speed;

controlling instantaneous engine torque output and operation of the at least one electric motor in accordance with variation in the RL to maintain the speed of the hybrid vehicle according to the desired cruising speed.

284. The method of claim 267, wherein the SP is at least approximately 30% of the MTO.

285. The method of claim 267,

wherein the hybrid vehicle is operated in a plurality of operating modes corresponding to values for the RL and the SP;

wherein said operating the at least one electric motor to drive the hybrid vehicle composes a low-load operation mode I;

wherein said operating the internal combustion engine of the hybrid vehicle to propel the hybrid vehicle composes a high-way cruising operation mode IV; and

wherein said operating both the at least one electric motor and the engine to propel the hybrid vehicle composes an acceleration operation mode V.

286. The method of claim 285, wherein the engine can be operated without transfer of power to the wheels of the hybrid vehicle during operation in mode I.

287. The method of claim 267, wherein the hybrid vehicle comprises a variable-ratio transmission disposed between the engine and the wheels of the hybrid vehicle.

288. The method of claim 287, wherein said variable-ratio transmission comprises a planetary gearbox.

289. The method of claim 267, wherein the engine is controllably coupled to one or more wheels of the hybrid vehicle by a clutch.

290. The method of claim 267, further comprising:

operating the engine at torque output levels less than the SP under abnormal and transient conditions to satisfy drivability and/or safety considerations.

291. The hybrid vehicle of claim 267, wherein the at least one electric motor is sufficiently powerful to provide acceleration of said vehicle sufficient to conform to the Federal urban cycle driving fuel mileage test without use of torque from the engine to propel the vehicle.

292. A hybrid vehicle, comprising:

a controller capable of accepting inputs indicative of vehicle operating parameters and providing control signals in response to a control program;

a battery bank;

an internal combustion engine operable to provide propulsive torque to road wheels of said vehicle;

a first AC electric starting motor electrically coupled to said battery bank and mechanically coupled to said internal combustion engine, and responsive to commands from said controller for (a) accepting electrical energy from said battery bank and (b) providing electrical energy to said battery bank, such that said first electric motor can be controlled to (1) accept torque from said engine to charge said battery bank, and (2) accept energy from said battery bank to apply torque to said engine for starting said engine;

a second AC electric traction motor, electrically coupled to said battery bank and mechanically coupled to road wheels of said vehicle, and responsive to commands from said controller, for (a) accepting electrical energy from said battery bank and (b) providing electrical energy to said battery bank such that said second electric motor can be controlled to (1) accept energy from said battery bank to apply torque to said road wheels to propel said vehicle, and (2) accept torque from said road wheels to charge said battery bank;

a solid state inverter connected to the second AC motor for converting DC to AC and AC to DC;

wherein said controller is provided with signals responsive to the instantaneous road load experienced by said vehicle and to the state of charge of said battery bank, and controls operation of said engine and said first and second motors so that said vehicle is operated in a plurality of operating modes responsive to said signals; and

wherein energy originating at the battery is supplied to the solid state inverter at a DC voltage having a peak of at least 500 volts.

293. The vehicle of claim 292 wherein energy originating at the battery is supplied to the solid state inverter at a maximum current of no more than about 75 amperes.

294. A hybrid vehicle, comprising:

a controller capable of accepting inputs indicative of vehicle operating parameters and providing control signals in response to a control program;

a battery bank;

an internal combustion engine operable to provide propulsive torque to road wheels of said vehicle;

a first AC electric starting motor electrically coupled to said battery bank and mechanically coupled to said internal combustion engine, and responsive to commands from said controller for (a) accepting electrical energy from said battery bank and (b) providing electrical energy to said battery bank, such that said first electric motor can be controlled to (1) accept torque from said engine to charge said battery bank, and (2) accept energy from said battery bank to apply torque to said engine for starting said engine;

a second AC electric traction motor, electrically coupled to said battery bank and mechanically coupled to road wheels of said vehicle, and responsive to commands from said controller, for (a) accepting electrical energy from said battery bank and (b) providing electrical energy to said battery bank such that said second electric motor can be controlled to (1) accept energy from said battery bank to apply torque to said road wheels to propel said vehicle, and (2) accept torque from said road wheels to charge said battery bank;

a solid state inverter connected to the second AC motor for converting DC to AC and AC to DC;

wherein said controller is provided with signals responsive to the instantaneous road load experienced by said vehicle and to the state of charge of said battery bank, and controls operation of said engine and said first and second motors so that said vehicle is operated in a plurality of operating modes responsive to said signals; and

wherein energy originating at the battery is supplied to the solid state inverter at a maximum current of no more than about 75 amperes.

295. A hybrid vehicle, comprising:

a controller capable of accepting inputs indicative of vehicle operating parameters and providing control signals in response to a control program;

a battery bank;

an internal combustion engine operable to provide propulsive torque to road wheels of said vehicle;

a first AC electric starting motor electrically coupled to said battery bank and mechanically coupled to said internal combustion engine, and responsive to commands from said controller for (a) accepting electrical energy from said battery bank and (b) providing electrical energy to said battery bank, such that said first electric motor can be controlled to (1) accept torque from said engine to charge said battery bank, and (2) accept energy from said battery bank to apply torque to said engine for starting said engine;

a second AC electric traction motor, electrically coupled to said battery bank and mechanically coupled to road wheels of said vehicle, and responsive to commands from said controller, for (a) accepting electrical energy from said battery bank and (b) providing electrical energy to said battery bank such that said second electric motor can be controlled to (1) accept energy from said battery bank to apply torque to said road wheels to propel said vehicle, and (2) accept torque from said road wheels to charge said battery bank;

a solid state inverter connected to the second AC motor for converting DC to AC and AC to DC;

wherein said controller is provided with signals responsive to the instantaneous road load experienced by said vehicle and to the state of charge of said battery bank, and controls operation of said engine and said first and second motors so that said vehicle is operated in a plurality of operating modes responsive to said signals; and

wherein energy originating at the battery is supplied to the solid state inverter at a voltage and current such that the ratio of voltage to current is at least about 2.5 to 1.

296. A hybrid vehicle, comprising:

a controller capable of accepting inputs indicative of vehicle operating parameters and providing control signals in response to a control program;

a battery bank;

an internal combustion engine operable to provide propulsive torque to road wheels of said vehicle;

a first AC electric starting motor electrically coupled to said battery bank and mechanically coupled to said internal combustion engine, and responsive to commands from said controller for (a) accepting electrical energy from said battery bank and (b) providing electrical energy to said battery bank, such that said first electric motor can be controlled to (1) accept torque from said engine to charge said battery bank, and (2) accept energy from said battery bank to apply torque to said engine for starting said engine;

a second AC electric traction motor, electrically coupled to said battery bank and mechanically coupled to road wheels of said vehicle, and responsive to commands from said controller, for (a) accepting electrical energy from said battery bank and (b) providing electrical energy to said battery bank such that said second electric motor can be controlled to (1) accept energy from said battery bank to apply torque to said road wheels to propel said vehicle, and (2) accept torque from said road wheels to charge said battery bank;

a solid state inverter connected to the second AC motor for converting DC to AC and AC to DC;

wherein said controller is provided with signals responsive to the instantaneous road load experienced by said vehicle and to the state of charge of said battery bank, and controls operation of said engine and said first and second motors so that said vehicle is operated in a plurality of operating modes responsive to said signals; and

wherein energy originating at the battery is supplied to the solid state inverter at a voltage having a peak of at least about 800 volts.

297. The vehicle of claim 296 wherein energy originating at the battery is supplied to the solid state inverter at a peak current of no more than 150 amperes.

298. A hybrid vehicle, comprising:

a controller capable of accepting inputs indicative of vehicle operating parameters and providing control signals in response to a control program;

a battery bank;

an internal combustion engine operable to provide propulsive torque to road wheels of said vehicle;

a first AC electric starting motor electrically coupled to said battery bank and mechanically coupled to said internal combustion engine, and responsive to commands from said controller for (a) accepting electrical energy from said battery bank and (b) providing electrical energy to said battery bank, such that said first electric motor can be controlled to (1) accept torque from said engine to charge said battery bank, and (2) accept energy from said battery bank to apply torque to said engine for starting said engine;

a second AC electric traction motor, electrically coupled to said battery bank and mechanically coupled to road wheels of said vehicle, and responsive to commands from said controller, for (a) accepting electrical energy from said battery bank and (b) providing electrical energy to said battery bank such that said second electric motor can be controlled to (1) accept energy from said battery bank to apply torque to said road wheels to propel said vehicle, and (2) accept torque from said road wheels to charge said battery bank;

a solid state inverter connected to the second AC motor for converting DC to AC and AC to DC;

wherein said controller is provided with signals responsive to the instantaneous road load experienced by said vehicle and to the state of charge of said battery bank, and controls operation of said engine and said first and second motors so that said vehicle is operated in a plurality of operating modes responsive to said signals; and

wherein energy originating at the battery is supplied to the solid state inverter at a maximum current of no more than 150 amperes.

299. A hybrid vehicle, comprising:

a controller capable of accepting inputs indicative of vehicle operating parameters and providing control signals in response to a control program;

a battery bank;

an internal combustion engine operable to provide propulsive torque to road wheels of said vehicle;

a first AC electric starting motor electrically coupled to said battery bank and mechanically coupled to said internal combustion engine, and responsive to commands from said controller for (a) accepting electrical energy from said battery bank and (b) providing electrical energy to said battery bank, such that said first electric motor can be controlled to (1) accept torque from said engine to charge said battery bank, and (2) accept energy from said battery bank to apply torque to said engine for starting said engine;

a second AC electric traction motor, electrically coupled to said battery bank and mechanically coupled to road wheels of said vehicle, and responsive to commands from said controller, for (a) accepting electrical energy from said battery bank and (b) providing electrical energy to said battery bank such that said second electric motor can be controlled to (1) accept energy from said battery bank to apply torque to said road wheels to propel said vehicle, and (2) accept torque from said road wheels to charge said battery bank;

a solid state inverter connected to the second AC motor for converting DC to AC and AC to DC;

wherein said controller is provided with signals responsive to the instantaneous road load experienced by said vehicle and to the state of charge of said battery bank, and controls operation of said engine such that said engine is operated only above a setpoint (SP), said setpoint SP varying as a function of said vehicle operating parameters.

300. The vehicle of claim 299, wherein said setpoint SP is varied as a function of vehicle speed.

301. The hybrid vehicle of claim 299, wherein the second electric motor is sufficiently powerful to provide acceleration of said vehicle sufficient to conform to the Federal urban cycle driving fuel mileage test without use of power from the engine to propel the vehicle.

302. A hybrid vehicle, comprising:

one or more wheels;

an internal combustion engine operable to propel the hybrid vehicle by providing torque to the one or more wheels;

a first electric motor coupled to the engine;

a second electric motor operable to propel the hybrid vehicle by providing torque to the one or more wheels;

a battery coupled to the first and second electric motors, operable to;

provide current to the first and/or the second electric motors; and

accept current from the first and second electric motors; and

a controller, operable to control the flow of electrical and mechanical power between the engine, the first and the second electric motors, and the one or more wheels;

a first alternating current-direct current (AC-DC) converter coupled to said first electric motor, at least operable to accept AC current and convert the current to DC;

a second AC-DC converter having an AC side coupled to said second electric motor, operable to accept AC or DC current and convert the current to DC or AC current respectively;

wherein said battery is coupled to a DC side of said AC-DC converters, wherein said battery is operable to store DC energy received from said AC-DC converters and provide DC energy to at least said second AC-DC converter for providing power to at least said second electric motor;

wherein a ratio of maximum DC voltage to maximum current supplied from said battery, measured on the DC side of at least said second AC-DC converter, is at least 2.5; and

wherein the controller is operable to operate the engine when the power required from the engine to satisfy the road load experienced by the vehicle and/or to drive one or more of the first and second motors to charge the battery is at least equal to a minimum value at which power is efficiently produced by said engine but that is substantially less than the maximum power output of the engine.

303. A hybrid vehicle, comprising:

one or more wheels;

an internal combustion engine operable to propel the hybrid vehicle by providing torque to the one or more wheels;

a first electric motor coupled to the engine;

a second electric motor operable to propel the hybrid vehicle by providing torque to the one or more wheels;

a battery coupled to the first and second electric motors, operable to;

provide current to the first and/or the second electric motors; and

accept current from the first and second electric motors; and

a controller, operable to control the flow of electrical and mechanical power between the engine, the first and the second electric motors, and the one or more wheels;

a first alternating current-direct current (AC-DC) converter coupled to said first electric motor, at least operable to accept AC current and convert the current to DC;

a second AC-DC converter having an AC side coupled to said second electric motor, operable to accept AC or DC current and convert the current to DC or AC current respectively;

wherein said battery is coupled to a DC side of said AC-DC converters, wherein said battery is operable to store DC energy received from said AC-DC converters and provide DC energy to at least said second AC-DC converter for providing power to at least said second electric motor;

wherein the peak DC voltage, measured on the DC side of at least said second AC-DC converter, is at least about 500 volts; and

wherein the controller is operable to operate the engine when the power required from the engine to satisfy the road load experienced by the vehicle and/or to drive one or more of the first and second motors to charge the battery is at least equal to a minimum value at which power is efficiently produced by said engine but that is substantially less than the maximum power output of the engine.

304. A hybrid vehicle, comprising:

one or more wheels;

an internal combustion engine operable to propel the hybrid vehicle by providing torque to the one or more wheels;

a first electric motor coupled to the engine;

a second electric motor operable to propel the hybrid vehicle by providing torque to the one or more wheels;

a battery coupled to the first and second electric motors, operable to;

provide current to the first and/or the second electric motors; and

accept current from the first and second electric motors; and

a controller, operable to control the flow of electrical and mechanical power between the engine, the first and the second electric motors, and the one or more wheels;

a first alternating current-direct current (AC-DC) converter coupled to said first electric motor, at least operable to accept AC current and convert the current to DC;

a second AC-DC converter having an AC side coupled to said second electric motor, operable to accept AC or DC current and convert the current to DC or AC current respectively;

wherein said battery is coupled to a DC side of said AC-DC converters, wherein said battery is operable to store DC energy received from said AC-DC converters and provide DC energy to at least said second AC-DC converter for providing power to at least said second electric motor;

wherein the peak DC current, measured on the DC side of at least said second AC-DC converter, is no more than about 150 amperes; and

wherein the controller is operable to operate the engine when the power required from the engine to satisfy the road load experienced by the vehicle and/or to drive one or more of the first and second motors to charge the battery is at least equal to a minimum value at which power is efficiently produced by said engine but that is substantially less than the maximum power output of the engine.

305. A hybrid vehicle, comprising:

one or more wheels;

an internal combustion engine operable to propel the hybrid vehicle by providing torque to the one or more wheels;

a first electric motor coupled to the engine;

a second electric motor operable to propel the hybrid vehicle by providing torque to the one or more wheels;

a battery coupled to the first and second electric motors, operable to;

provide current to the first and/or the second electric motors; and

accept current from the first and second electric motors; and

a controller, operable to control the flow of electrical and mechanical power between the engine, the first and the second electric motors, and the one or more wheels;

wherein energy originating at the battery is supplied to the second motor at a peak voltage of at least about 500 volts; and

wherein the controller is operable to operate the engine when the power required from the engine to satisfy the road load experienced by the vehicle and/or to drive one or more of the first and second motors to charge the battery is at least equal to a minimum value at which power is efficiently produced by said engine but that is substantially less than the maximum power output of the engine.

306. A hybrid vehicle, comprising:

one or more wheels;

an internal combustion engine operable to propel the hybrid vehicle by providing torque to the one or more wheels;

a first electric motor coupled to the engine;

a second electric motor operable to propel the hybrid vehicle by providing torque to the one or more wheels;

a battery coupled to the first and second electric motors, operable to;

provide current to the first and/or the second electric motors; and

accept current from the first and second electric motors; and

a controller, operable to control the flow of electrical and mechanical power between the engine, the first and the second electric motors, and the one or more wheels;

wherein power originating at the battery is supplied to the second motor at a peak current no greater than about 150 amperes; and

wherein the controller is operable to operate the engine when the power required from the engine to satisfy the road load experienced by the vehicle and/or to drive one or more of the first and second motors to charge the battery is at least equal to a minimum value at which power is efficiently produced by said engine but that is substantially less than the maximum power output of the engine.