Electric hybrid vehicle and method of controlling it

• US 5,081,365 A
• Filed: 06/06/1990
• Issued: 01/14/1992
• Est. Priority Date: 06/06/1990
• Status: Expired due to Term

• Current Assignee: Bruce F. Field, Charles W. Bricher
• Original Assignee: Bruce F. Field, Charles W. Bricher
• Inventors: Bricher, Charles W., Field, Bruce F.
• Primary Examiner(s): Pellinen, A. D.
• Assistant Examiner(s): HOOVER, ROBERT
• Application Number:
  US07/534,116
• Time in Patent Office: 587 Days
• Field of Search: 290/45, 290/50
• US Class Current: 290/45
• CPC Class Codes: B60K 31/00 Vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed, i.e. preventing speed from exceeding an arbitrarily established velocity or maintaining speed at a particular velocity, as selected by the vehicle operator fittings acting on two or more sub-units B60W30/14; speedometers G01P; systems or devices for controlling speed in general G05D13/00 ; in traffic anti-collision system for road vehicles G08G1/16
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 1/003 to auxiliary motors, e.g. for pumps, compressors
• CPC Class Codes: B60L 1/14 to electric lighting circuits
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/425 Temperature
• CPC Class Codes: B60L 2250/10 by alarm
• CPC Class Codes: B60L 2250/16 by display
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 50/30 using propulsion power stored mechanically, e.g. in fly-wheels
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/04 including control of propulsion units
• 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 10/26 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 2510/244 Charge state
• CPC Class Codes: B60W 2710/081 : Speed
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y10S 903/946 : Characterized by control of driveline clutch

Abstract

A method of operating a vehicle having an electric hybrid power system comprising a battery powered electric motor connected to drive the wheels of the vehicle and a combustion engine which may be releasably coupled mechanically to the electric motor. When so coupled the combustion engine may drive the vehicle and the electric motor may act as a generator to maintain a desired charge level in the batteries. In operation the power train is automatically controlled by a process controller to produce maximum fuel economy for the engine and to maintain the batteries at an acceptable charge level. Means are provided to apply the combined power of the electric motor and the combustion engine to the drive wheels for short duration peaking power. Means are also provided whereby the combustion engine may drive the electric motor to function as a generator and charge the batteries when the vehicle is stationary.

Claims

1. In a vehicle having an electric hybrid power system comprising an electric motor suitably coupled mechanically to drive one or more ground engaging wheels, battery means for storing electricity in suitable form to power the electric motor, a combustion engine and a supply of fuel for it so arranged that the engine may be releasably coupled mechanically to the electric motor, whereby the engine may drive the electric motor and whereby the electric motor when driven by the engine may be selectively operated as a mechanical coupling to transmit engine power mechanically to the wheels, or as a battery powered electric motor to supply power to the wheels, or as a generator to supply electricity to the battery means, or as some combination of said coupling, motor and generator,

a motor controller to supply a controllably variable flow of electrical current to the electric motor from the battery means or to the battery means from the electric motor, during which latter condition the electric motor is operating as a generator,

a process controller having inputs from a variable accelerator control, a highway mode switch, an engine mode switch, a cruise control switch, a brake switch, a sensor reporting the charge level of the battery means, and speed sensors reporting the speeds of the electric motor and the combustion engine, and having outputs to the motor controller, to means for starting and stopping the combustion engine, to means for controlling and varying the speed of the combustion engine, and to means to selectively effect mechanical coupling of the combustion engine and the electric motor,

a cruise control which can function through the process controller to maintain the electric motor at an essentially constant speed by controlling the speed output of the combustion engine or the electric motor in spite of variations in the load on the combustion engine or the electric motor and regardless of whether the vehicle is being powered by the electric motor or the combustion engine, and regardless of whether the vehicle is moving or stationary,

a method of controlling the hybrid power system comprising:

a) operating the vehicle in a first or urban mode in which the combustion engine is mechanically uncoupled from the electric motor so all the power for driving the vehicle comes from the electric motor, and at desired rates of acceleration and steady speed by controlling current flow to the electric motor from the battery means, and during desired periods of deceleration feeding current from the electric motor to the battery means, with the electric motor operating as a generator, the current flow to or from the electric motor during said urban mode operation being controlled by said motor controller which in turn is controlled by said variable accelerator control, or

b) operating the vehicle in a second or highway mode after the vehicle is in motion and the electric motor is rotating above a pre-selected speed by sensing the charge level of the battery means and comparing it to a first pre-established charge level, and if the battery means charge level is above the said first pre-established charge level operating the vehicle in a first operating condition which is the same as the said urban mode, except that the combustion engine may optionally be operating at idle speed instead of stopped,

but if the charge level of the battery means is at or below the said first pre-established charge level, operating in a second operating condition by starting the combustion engine and/or bringing it up to the speed at which the electric motor is then being operated, then mechanically coupling the combustion engine to the electric motor, thus connecting the combustion engine power mechanically to the electric motor and to the ground engaging drive wheels of the vehicle, whereby the vehicle may be driven by a portion of the power of the combustion engine and the balance of the combustion engine power may be used by the electric motor which, acting as a generator, will recharge the battery means,

periodically monitoring the charge level of the battery means until it builds up to a second pre-established charge level which is higher than the first pre-established charge level, then reverting to the said first operating condition, and continuing to thus alternate between said first operating condition and said second operating condition, or

c) operating the automobile in a third or engine mode in which the combustion engine is mechanically coupled continuously to the electric motor and thereby mechanically connected continuously to the ground engaging drive wheels of the vehicle regardless of the charge level of the battery means, and

d) operating the cruise control when desired in conjunction with the third or engine mode to control the speed of the electric motor, in which condition the accelerator pedal may be used if desired to direct the motor controller to feed current from the battery means to the electric motor to provide power from the electric motor to supplement the power of the combustion engine, or

e) operating the combustion engine when the vehicle is stationary to power the electric motor which, acting as a generator, will charge the battery means, with the speed of the combustion engine being held constant by the cruise control, and

f) controlling all the functions in the urban, highway and engine modes and all the functions of the cruise control by the process controller so that all the functions are controlled and performed automatically.

2. The control method for the electric hybrid vehicle of claim 1 in which the first pre-established battery means charge level is approximately 70% of full battery means charge level and the second pre-established battery means charge level is approximately 95% of full battery means charge level.