METHOD AND DEVICE FOR CONTROLLING A CREEP MODE OF A VEHICLE HAVING A HYBRID DRIVE SYSTEM

• US 20110039655A1
• Filed: 12/02/2008
• Published: 02/17/2011
• Est. Priority Date: 12/13/2007
• Status: Active Grant

• Current Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Mittelberger, Christian, Wallner, Stefan, Bornträger, Kai, Kaltenbach, Johannes
• Granted Patent: US 8,475,330 B2
• Time in Patent Office: Days
• 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 (1, 1′

), having a parallel hybrid drive train (2, 2′

) comprised of an internal combustion engine (3), at least one electric machine (5), a first clutch element (4) in the form of a friction clutch located between the internal combustion engine (3) and the electric machine (5), whereby the internal combustion engine (3) and the electric machine (5) may be connected, a transmission (7), an output (26), and at least one second clutch element (6) in the form of a friction clutch located between the electric machine (5) and the output (26), whereby the electric machine (5) may be functionally connected to the output (26), characterized in that the creep mode is obtained alternately through the means of operating at least one clutch element (6, 27) in slippage mode generated internal combustion engine creep mode and an, at least supported by the electric machine (5), electric motor creep mode.

2. A process in accordance with claim 1, characterized in that in a creep mode extended over a period of time of the vehicle, cyclically alternating, in a first step with an engaged first clutch element (4) the electric machine (5) is operated as a generator by the internal combustion engine (3) and at lest the second clutch element (6) is operated in slippage mode, and in a second step, without a slipping clutch element (6) between the electric machine (5) and the output (26), at least the electric machine (5) is operated as a motor for generating the creep mode.

3. A process in accordance with claim 2, characterized in that in the first step at least one additional, located between the electric machine (5) and the output (26), third clutch element (27) alternately or in combination with the second clutch element (6) is operated in slippage mode.

4. A process in accordance with claim 2, characterized in that in the second step, in addition to the motor operation of the electric machine (5), the first clutch element (4) is operated in slippage mode.

5. A process in accordance with claim 2, characterized in that with a priority for electric energy the electric machine (5) is operated as a generator and at the same time the first clutch element (4) is operated in slippage mode.

6. A process in accordance with claim 2, characterized in that the change between the internal combustion engine and electric motor creep modes occurs dependent on a state of charge in an electric energy storage unit (14).

7. A process in accordance with claim 6, characterized in that the internal combustion creep mode is activated when the state of charge of the energy storage unit (14) has reached an upper threshold value.

8. A device for controlling a creep mode of a vehicle with a hybrid electric power train (1, 1′

), having a parallel hybrid drive train (2, 2′

) comprised of an internal combustion engine (3), at least one electric machine (5), a first clutch element (4) in the form of a friction clutch located between the internal combustion engine (3) and the electric machine (5), whereby the internal combustion engine (3) and the electric machine (5) may be connected, a transmission (7), an output (26), and at least one second clutch element (6) in the form of a friction clutch located between the electric machine (5) and the output (26), whereby the electric machine (5) may be functionally connected to the output (26), characterized in that control means (21, 25) are available whereby the creep mode may be obtained alternately through the internal combustion engine, by means of activating at least one clutch element (6, 27) in slippage mode, and by means of activating the electric machine (5) which is at least supported by the electric motor.

9. A device in accordance with claim 8, characterized in that the second clutch element (6) is constructed as a friction clutch, external to the transmission, located between the electric machine (5) and the transmission (7).

10. A device in accordance with claim 8, characterized in that the second clutch element and optional additional clutch elements (27) available for the creep mode are constructed as frictionally engaged geared clutches and/or geared brakes inside of the transmission.