Method and device for controlling a creep mode of a vehicle having a hybrid drive system

• US 8,475,330 B2
• Filed: 12/02/2008
• Issued: 07/02/2013
• Est. Priority Date: 12/13/2007
• Status: Expired due to Fees

• Current Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Kaltenbach, Johannes, Wallner, Stefan, Mittelberger, Christian, Borntrger, Kai
• Primary Examiner(s): PANG, ROGER L
• Application Number:
  US12/747,143
• Publication Number:
  US 20110039655A1
• Time in Patent Office: 1,673 Days
• Field of Search: 477/5, 477/174, 477/180, 180/65.245, 180/65.265
• US Class Current: 477/5
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 2240/507 Operating parameters
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• 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 20/40 Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers power-up or power-down of the driveline B60W30/192
• CPC Class Codes: B60W 2510/0291 Clutch temperature
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2710/025 Clutch slip, i.e. difference between input and output speeds
• CPC Class Codes: B60W 30/18063 Creeping
• CPC Class Codes: B60W 30/1843 Overheating of driveline components B60W30/186 takes precedence
• CPC Class Codes: B60W 30/1846 Preventing of breakage of drive line components, e.g. parts of the gearing
• CPC Class Codes: B60W 30/186 excessive wear or burn out of friction elements, e.g. clutches
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

The invention relates to a method and a device for controlling a creep mode of a vehicle having a hybrid drive system (1, 1′), having a parallel hybrid drivetrain (2, 2′) comprising an internal combustion engine (3), at least one electrical machine (5), a first switching element (4) designed as a frictional element and disposed between the internal combustion engine (3) and the electrical machine (5), by means of which the internal combustion engine (3) can be connected to the electrical machine (5), a gearbox (7), an output (26), and at least one second switching element (6) designed as a frictional element and disposed between the electrical machine (5) and the output (26), by means of which the electrical machine (5) can be operationally connected to the output (26). In order to allow low-cost, effective long-term creeping that is gentle on the components, and thereby ensures reliable availability of electrical energy for electrical loads of the vehicle, the creep mode is alternately implemented by an internal combustion engine creep mode generated by means of operating at least one switching element (6, 27) in slip, and an electrical motor creep mode at least supported by means of the electrical machine (5).

Claims

1. A process for controlling a creep mode of a vehicle with a hybrid electric power train, the hybrid electric power train comprising:

an internal combustion engine,

an electric machine,

a first clutch element located between the internal combustion engine and the electric machine, whereby the internal combustion engine and the electric machine are connectable with respect to each other,

a transmission,

an output,

a second clutch element and a third clutch element located between the electric machine and the output, whereby the electric machine is connectable to the output;

the process characterized in that the creep mode is obtained alternately through the means of operating at least the second clutch element and the third clutch element, alternately or in combination thereof, in slippage mode generated internal combustion engine creep mode and an, at least supported by the electric machine, electric motor creep mode.

2. The process according to claim 1, characterized in that in a creep mode extended over a period of time of the vehicle, cyclically alternating a first step and a second step, wherein

the first step comprises:

engaging the first clutch element;

operating the electric machine as a generator driven by the internal combustion engine; and

operating at least the second clutch element and the third clutch element, alternately or in combination in slippage mode; and

the second step comprises;

engaging the second clutch element or the third clutch element; and

operating the electric machine as a motor.

3. The process according to claim 2, wherein in the second step further comprises operating the first clutch element in slippage mode.

4. The process according to claim 2, wherein the first step further comprises:

operating the electric machine as a generator; and

operating the first clutch element in slippage mode.

5. The process according to claim 2, wherein the electric machine connects to an electric energy storage unit, and the change between the first step and the second step occurs dependent on a state of charge in the electric energy storage unit.

6. The process according to claim 5, wherein the first step is operated when the state of charge of the energy storage unit has reached an upper threshold value.

7. The process according to claim 1, wherein the first clutch element is a friction clutch.

8. The process according to claim 1, wherein the second clutch element is a friction clutch.

9. The process according to claim 1, wherein the third clutch element is a friction clutch.

10. The process according to claim 1, wherein the transmission comprises the third clutch element.

11. The process according to claim 7, wherein the second clutch element is located between the electric machine and the transmission.

12. The process according to claim 7, wherein the transmission is located between the electric machine and the output.

13. The process according to claim 2, wherein in second step the second clutch element is engaged when the third clutch element is operating in slippage mode.

14. The process according to claim 2, wherein the second step further comprises disengaging the first clutch element.

15. A device for controlling a creep mode of a vehicle with a hybrid electric power train, the hybrid electric power train comprising:

an internal combustion engine,

an electric machine,

a first clutch element located between the internal combustion engine and the electric machine, whereby the internal combustion engine and the electric machine are connectable with respect to each other,

a transmission,

an output,

a second clutch element and a third clutch element located between the electric machine and the output, whereby the electric machine is connectable to the output;

the device comprising a control means operable to alternate the creep mode either through the internal combustion engine, by means of activating at least the second clutch element and third clutch element, alternately or in combination thereof, in slippage mode, or through the electric machine, by means of engaging the second clutch element or the third clutch element.

16. The device according to claim 15, wherein the second clutch element is a friction clutch, external to the transmission, and located between the electric machine and the transmission.

17. The device according to claim 15, wherein the second clutch element and the third clutch elements are one of frictionally engaged geared clutches and geared brakes inside of the transmission.

18. The device according to claim 15, wherein the electric machine connects to an electric energy storage unit.

19. The device according to claim 15, wherein the electric machine is operable as a motor.

20. The device according to claim 15, wherein the electric machine is operable as a generator.