METHOD AND APPARATUS TO CONTROL ENGINE TORQUE TO PEAK MAIN PRESSURE FOR A HYBRID POWERTRAIN SYSTEM

• US 20090118083A1
• Filed: 10/13/2008
• Published: 05/07/2009
• Est. Priority Date: 11/04/2007
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG, Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Original Assignee: BMW AG (Bayerische Motoren Werke AG), GM Global Technology Operations Incorporated (General Motors Company), Daimler AG (Mercedes-Benz Group AG), Chrysler LLC (Stellantis NV)
• Inventors: Heap, Anthony H., Sah, Jy-Jen F., Kaminsky, Lawrence A.
• Granted Patent: US 8,079,933 B2
• Time in Patent Office: Days
• US Class Current: 477/5
• CPC Class Codes: B60K 6/36 characterised by the transmission gearings
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 2240/425 Temperature
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60L 2240/485 Temperature
• CPC Class Codes: B60L 2240/486 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 2050/0006 Digital architecture hierarchy
• CPC Class Codes: B60W 2050/0031 Mathematical model of the vehicle
• CPC Class Codes: B60W 2510/0216 Clutch engagement rate
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/0671 Engine manifold pressure
• CPC Class Codes: B60W 2510/0676 Engine temperature
• CPC Class Codes: B60W 2510/087 : Temperature
• CPC Class Codes: B60W 2510/1015 : Input shaft speed, e.g. turbine speed
• CPC Class Codes: B60W 2510/104 : Output speed
• CPC Class Codes: B60W 2510/107 : Temperature
• CPC Class Codes: B60W 2510/1075 : fluid pressure, e.g. oil pressure
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2540/10 : Accelerator pedal position
• CPC Class Codes: B60W 2540/12 : Brake pedal position
• CPC Class Codes: B60W 2540/16 : Ratio selector position
• CPC Class Codes: B60W 2555/20 : Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60W 2710/0605 : Throttle position
• CPC Class Codes: B60W 2710/0616 : Position of fuel or air injector
• CPC Class Codes: B60W 2710/0666 : Engine torque
• CPC Class Codes: B60W 30/184 : Preventing damage resulting from overload or excessive wear of the driveline
• 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: B60W 50/0097 : Predicting future conditions
• CPC Class Codes: F16H 2037/104 : Power split variators with one end of the CVT connected or connectable to two or more differentials
• CPC Class Codes: F16H 3/728 : with means to change ratio in the mechanical gearing
• CPC Class Codes: F16H 35/10 : Arrangements or devices for absorbing overload or preventing damage by overload for screw mechanisms F16H25/2021
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility

Abstract

A method to control a powertrain including a transmission, an engine, and an electric machine includes monitoring a rotational speed of the engine, monitoring a temperature of a transmission fluid, determining a maximum hydraulic pressure within a hydraulic control system based upon the rotational speed of the engine and the temperature of the transmission fluid, determining a predicted clutch torque capacity based upon the maximum hydraulic pressure, generating a preferred input torque from the engine based upon the predicted clutch torque capacity, and utilizing the preferred input torque to control the engine.

Claims

1. Method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member, said method comprising:

monitoring a rotational speed of said engine;

monitoring a temperature of a transmission fluid;

determining a maximum hydraulic pressure within a hydraulic control system based upon said rotational speed of said engine and said temperature of said transmission fluid;

determining a predicted clutch torque capacity based upon said maximum hydraulic pressure;

generating a preferred input torque from said engine based upon said predicted clutch torque capacity; and

utilizing said preferred input torque to control said engine.

2. The method of claim 1, further comprising:

monitoring an actual input torque resulting from said control of said engine;

determining a current hydraulic pressure based upon said rotational speed of said engine and said temperature of said transmission fluid;

determining a current clutch torque capacity based upon said current hydraulic pressure; and

generating electric machine torque commands based upon said current clutch torque capacity and said actual input torque.

3. The method of claim 2, wherein determining said current hydraulic pressure is further based upon a speed of an auxiliary hydraulic pump.

4. The method of claim 2, wherein determining said maximum hydraulic pressure is further based upon a maximum speed of said auxiliary hydraulic pump.

5. The method of claim 2, wherein determining said current hydraulic pressure is further based upon operation of a hydraulic control system including flows to functions served by said hydraulic control system.

6. The method of claim 2, said generating electric machine torque commands includes commands to a second electric machine.

7. The method of claim 1, wherein determining a maximum hydraulic pressure is further based upon a maximum speed of an auxiliary hydraulic pump.

8. The method of claim 1, wherein determining said maximum hydraulic pressure is further based upon operation of said hydraulic control system including flows to functions served by said hydraulic control system.

9. Method for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member, said method comprising:

monitoring a temperature of a transmission fluid;

monitoring a maximum hydraulic flow from a main hydraulic pump and an auxiliary hydraulic pump;

monitoring operation of a hydraulic control system fluidly connected to said main hydraulic pump and said auxiliary hydraulic pump;

determining a maximum hydraulic pressure of said hydraulic control system based upon said maximum hydraulic flow, said temperature of said transmission fluid, and said operation of said hydraulic control system;

determining a predicted clutch torque capacity based upon said maximum hydraulic pressure;

determining a preferred input torque from said engine based upon said predicted clutch torque capacity; and

utilizing said preferred input torque to control said engine.

10. The method of claim 9, further comprising:

monitoring an actual input torque resulting from said control of said engine;

monitoring a current hydraulic flow from a main hydraulic pump and an auxiliary hydraulic pump;

determining a current hydraulic pressure of said hydraulic control system based upon said current hydraulic flow and said temperature of said transmission fluid;

determining a current clutch torque capacity based upon said current hydraulic pressure; and

generating electric machine torque commands based upon said current clutch torque capacity and said actual input torque.

11. The method of claim 10, further comprising generating electric machine torque commands to a second electric machine based upon said current clutch torque capacity and said actual input torque.

12. Apparatus for controlling a powertrain comprising an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine adapted to selectively transmit mechanical power to an output member, said apparatus comprising:

a plurality of hydraulically actuated clutches achieving said selective transmission of power;

a main hydraulic pump;

an auxiliary hydraulic pump;

a hydraulic control system fluidly connected to said main hydraulic pump and said auxiliary hydraulic pump and providing hydraulic flows to a plurality of functions including said clutches; and

a powertrain control system including programming to

monitor a speed of said main hydraulic pump,

monitor a maximum speed of said auxiliary hydraulic pump,

monitor a temperature of a transmission fluid,

monitor operation of said hydraulic control system,

determine a maximum hydraulic pressure of said hydraulic control system based upon said speed of said main hydraulic pump, said maximum speed of said auxiliary hydraulic pump, said temperature of said transmission fluid, and said operation of said hydraulic control system,

determine a predicted clutch torque capacity based upon said maximum hydraulic pressure,

determine a preferred input torque from said engine based upon said predicted clutch torque capacity, and

control said engine based upon said preferred input torque.

13. The apparatus of claim 12,

wherein said powertrain control system further includes programming to monitor a current speed of said auxiliary hydraulic pump,

determine a current hydraulic pressure of said hydraulic control system based upon said speed of said main hydraulic pump, said current speed of said auxiliary hydraulic pump, said temperature of said transmission fluid, and said operation of said hydraulic control system,

determine a current clutch torque capacity based upon said current hydraulic pressure, and

generate electric machine torque commands based upon said current clutch torque capacity and said preferred input torque from said engine.

14. The apparatus of claim 13,

wherein said powertrain control system further includes programming to generate electric machine torque commands to a second electric machine based upon said current clutch torque capacity and said preferred input torque from said engine.