Method for controlling a hybrid drive which drives a vehicle

• US 5,327,992 A
• Filed: 04/28/1993
• Issued: 07/12/1994
• Est. Priority Date: 05/28/1992
• Status: Expired due to Term

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: Mercedes-Benz AG (Mercedes-Benz Group AG)
• Inventors: Boll, Wolf
• Primary Examiner(s): Focarino, Margaret A.
• Assistant Examiner(s): ENGLISH, PETER C
• Application Number:
  US08/053,262
• Time in Patent Office: 440 Days
• Field of Search: 180/65.2, 180/65.3, 180/65.4, 180/65.6, 180/65.7, 180/65.8, 290/45, 290/50
• US Class Current: 180/65.25
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 2270/12 of exhaust
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• 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 10/10 including control of change-speed gearings
• 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 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2530/16 Driving resistance
• CPC Class Codes: B60Y 2300/476 Regeneration of particle filters
• CPC Class Codes: F01N 3/02 for cooling, or for removing solid constituents of, exhaust by means of electric or electrostatic separators F01N3/01 ; mixing air with exhaust in tailpipes F01N13/082, F01N13/20
• CPC Class Codes: F01N 3/023 using means for regenerating the filters, e.g. by burning trapped particles by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02D 2041/026 using an external load, e.g. by increasing generator load or by changing the gear ratio
• CPC Class Codes: F02D 41/029 the exhaust gas treating apparatus being a particulate filter
• CPC Class Codes: Y02T 10/40 Engine management systems
• 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 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y10S 903/903 : having energy storing means, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/919 : Stepped shift
• CPC Class Codes: Y10S 903/945 : Characterized by control of gearing, e.g. control of transmission ratio

Abstract

A method for controlling a hybrid drive consisting of an internal combustion engine and at least one electric motor which can be driven via an electrical energy source, in which the electric motor can be operated as a generator when required. In order to reduce the fuel consumption and the emission of noxious substances of the internal combustion engine in those operating ranges in which the torque to be output by the internal combustion engine to overcome the instantaneous tractive resistances lies below a torque corresponding to ideal operation of the internal combustion engine with respect to efficiency and/or exhaust gas behavior, the internal combustion engine is operated essentially with the torque corresponding to ideal operation. The differential torque between the torque corresponding to ideal operation and the torque to be output by the internal combustion engine to overcome the instantaneous tractive resistances is used to drive the electric motor which is switched as a generator.

Claims

1. Method for controlling a hybrid drive that drives a vehicle, the hybrid drive including an internal combustion engine and at least one electric motor which can be driven via an electrical energy source, the method comprising the steps:

switching the electric motor over to a generator mode when a present requirement to generate electric energy is present;

operating the internal combustion engine substantially at a torque corresponding to ideal operation of the internal combustion engine with respect to at least one of efficiency and exhaust gas behavior when the internal combustion engine is in operating ranges in which an amount of torque to be output by the internal combustion engine for overcoming instantaneous tractive resistances lies below a torque corresponding to the ideal operation of the internal combustion engine; and

using a differential torque between the torque corresponding to the ideal operation and the torque to be output by the internal combustion engine for overcoming the instantaneous tractive resistances to drive the electric motor operated as a generator;

wherein the internal combustion engine is a diesel engine which is coupled to a soot filter via an exhaust gas line, and further comprising the step of controlling the amount of torque taken up by the electric motor operating in the generator mode such that, as a function of operating parameters, exhaust gas temperatures are reached which causes automatic burning off of the soot filter.

2. Method according to claim 1, further comprising controlling the amount of torque taken up by the electric motor operating in generator mode to a set value corresponding to the differential torque.

3. Method according to claim 2, wherein a battery is coupled to the electric motor and is an energy source to drive the electric motor, further comprising the step of operating the internal combustion engine at a torque equal to a set value which is greater than the torque corresponding to ideal operation, whenever the battery is discharged to a severe degree.

4. Method according to claim 1, further comprising controlling the hybrid drive according to a characteristic diagram.

5. Method according to claim 4, wherein a battery is coupled to the electric motor and is an energy source to drive the electric motor, further comprising the step of operating the internal combustion engine at a torque equal to a set value which is greater than the torque corresponding to ideal operation, whenever the battery is discharged to a severe degree.

6. Method according to claim 1, wherein a battery is coupled to the electric motor and is an energy source to drive the electric motor, further comprising the step of operating the internal combustion engine at a torque equal to a set value which is greater than the torque corresponding to ideal operation, whenever the battery is discharged to a severe degree.

7. Method according to claim 1, wherein an automatic transmission is coupled to at least one of the internal combustion engine and the electric motor, and further comprising the step of controlling the transmission such that, with a discharged battery, a low gear is selected.

8. Method according to claim 1, further comprising controlling the amount of torque taken up by the electric motor operating in generator mode to a set value corresponding to the differential torque.

9. Method for controlling a hybrid drive that drives a vehicle, the hybrid drive including an internal combustion engine and at least one electric motor which can be driven via an electrical energy source, the method comprising the steps:

switching the electric motor over to a generator mode when a preset requirement to generate electric energy is present;

operating the internal combustion engine substantially at a torque corresponding to ideal operation of the internal combustion engine with respect to at least one of efficiency and exhaust gas behavior when the internal combustion engine is in operating ranges in which an amount of torque to be output by the internal combustion engine for overcoming instantaneous tractive resistances lies below a torque corresponding to the ideal operation of the internal combustion engine; and

using a differential torque between the torque corresponding to the ideal operation and the torque to be output by the internal combustion engine for overcoming the instantaneous tractive resistances to drive the electric motor operated as a generator;

wherein the internal combustion engine is a diesel engine which is coupled to a soot filter via an exhaust gas line, and further comprising the step of controlling the amount of torque taken up by the electric motor operating in the generator mode such that exhaust gas temperatures are constantly reached which causes automatic burning off of the soot filter.

10. Method according to claim 9, further comprising controlling the amount of torque taken up by the electric motor operating in generator mode to a set value corresponding to the differential torque.

11. Method according to claim 10, wherein a battery is coupled to the electric motor and is an energy source to drive the electric motor, further comprising the step of operating the internal combustion engine at a torque equal to a set value which is greater than the torque corresponding to ideal operation, whenever the battery is discharged to a severe degree.

12. Method according to claim 9, further comprising controlling the hybrid drive according to a characteristic diagram.

13. Method according to claim 12, wherein a battery is coupled to the electric motor and is an energy source to drive the electric motor, further comprising the step of operating the internal combustion engine at a torque equal to a set value which is greater than the torque corresponding to ideal operation, whenever the battery is discharged to a severe degree.

14. Method according to claim 9, wherein a battery is coupled to the electric motor and is an energy source to drive the electric motor, further comprising the step of operating the internal combustion engine at a torque equal to a set value which is greater than the torque corresponding to ideal operation, whenever the battery is discharged to a severe degree.

15. Method according to claim 9, wherein an automatic transmission is coupled to at least one of the internal combustion engine and the electric motor, and further comprising the step of controlling the transmission such that, with a discharged battery, a low gear is selected.

16. Method according to claim 9, further comprising controlling the amount of torque taken up by the electric motor operating in generator mode to a set value corresponding to the differential torque.