METHOD AND APPARATUS TO CONTROL HYDRAULIC PRESSURE FOR COMPONENT LUBRICATION IN AN ELECTRO-MECHANICAL TRANSMISSION

• US 20090111637A1
• Filed: 10/08/2008
• Published: 04/30/2009
• Est. Priority Date: 10/26/2007
• Status: Active Grant

• Current Assignee: Bayerische Motoren Werke AG, Daimler AG (Mercedes-Benz Group AG), Chrysler Group LLC (Stellantis NV)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Day, Kristin L., Sah, Jy-Jen F.
• Granted Patent: US 7,985,154 B2
• Time in Patent Office: Days
• US Class Current: 475/159
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 2001/003 with means for cooling the electrical propulsion units
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• 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 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/445 Temperature
• 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 10/115 with planetary gears
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• 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 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2050/0006 Digital architecture hierarchy
• 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 2510/081 Speed
• CPC Class Codes: B60W 2510/1075 : fluid pressure, e.g. oil pressure
• CPC Class Codes: B60W 2540/10 : Accelerator pedal position
• CPC Class Codes: B60W 2540/12 : Brake pedal 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 2710/083 : Torque
• CPC Class Codes: F16H 2037/106 : with switching means to provide two variator modes or ranges
• CPC Class Codes: F16H 2061/0037 : characterised by controlled fluid supply to lubrication circuits of the gearing see also lubrication control F16H57/0446
• CPC Class Codes: F16H 3/728 : with means to change ratio in the mechanical gearing
• CPC Class Codes: F16H 57/0475 : Engine and gearing, i.e. joint lubrication or cooling or heating thereof electric machines and gearing F16H57/0476
• CPC Class Codes: F16H 61/0031 : using auxiliary pumps, e.g. pump driven by a different power source than the engine
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility

Abstract

A method for controlling hydraulic line pressure for component lubrication in a transmission includes monitoring a speed of an engine and an electric machine, determining a minimum line pressure required to lubricate the engine based upon the speed of the engine, determining a minimum line pressure required to lubricate the electric machine based upon the speed of the electric machine, controlling a minimum line pressure of a hydraulic control system to at least satisfy a larger value of the minimum line pressures.

Claims

1. Method for controlling hydraulic line pressure for component lubrication in an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and an electric machine, and adapted to selectively transmit mechanical power to an output member, said method comprising:

monitoring a speed of said engine;

monitoring a speed of said electric machine;

determining a minimum line pressure required to lubricate said engine based upon said speed of said engine;

determining a minimum line pressure required to lubricate said electric machine based upon said speed of said electric machine; and

controlling a minimum line pressure of a hydraulic control system to at least satisfy a larger value of said minimum line pressure required to lubricate said engine and said minimum line pressure required to lubricate said electric machine.

2. The method of claim 1, further comprising:

monitoring a speed of a second electric machine;

determining a minimum line pressure required to lubricate said second electric machine based upon said speed of said second electric machine; and

controlling said minimum line pressure of a hydraulic control system to at least satisfy a largest value of said minimum line pressure required to lubricate said engine, said minimum line pressure required to lubricate said electric machine, and said minimum line pressure required to lubricate said second electric machine.

3. The method of claim 2, wherein controlling said minimum line pressure of a hydraulic control system comprises:

monitoring a minimum line pressure required to operate clutches within said transmission;

monitoring a minimum line pressure require to cool said electric machine and said second electric machine; and

selecting said minimum line pressure of a hydraulic control system based upon a largest value of said minimum line pressure required to

lubricate said engine,

lubricate said electric machine,

lubricate said second electric machine,

operate clutches within said transmission, and

cool said electric machine and said second electric machine.

4. The method of claim 1, wherein controlling said minimum line pressure of a hydraulic control system comprises:

monitoring a minimum line pressure required to operate clutches within said transmission;

monitoring a minimum line pressure required to cool said electric machine and said second electric machine; and

selecting said minimum line pressure of a hydraulic control system based upon a largest value of said minimum line pressure required to

lubricate said engine,

lubricate said electric machine,

operate clutches within said transmission, and

cool said electric machine and said second electric machine.

5. A method for maintaining a minimum hydraulic line pressure for component lubrication in a hybrid powertrain comprising an internal combustion engine and an electric machine transmitting mechanical power to an output member, the method comprising:

monitoring a speed of said engine;

monitoring a speed of said electric machine;

determining a minimum line pressure required to lubricate said engine based upon said speed of said engine;

determining a minimum line pressure required to lubricate said electric machine based upon said speed of said electric machine;

comparing said minimum line pressure required to lubricate said engine and said minimum line pressure required to lubricate said electric machine to find a greater of said minimum line pressures;

selecting a minimum line pressure for lubrication based upon said comparing; and

controlling a minimum line pressure of a hydraulic control system based upon said minimum line pressure for lubrication.

6. The method of claim 5, further comprising:

monitoring a speed of a second electric machine; and

determining a minimum line pressure required to lubricate said second electric machine based upon said speed of said second electric machine; and

wherein said comparing further comprises comparing said minimum line pressures to find a greatest of said minimum line pressures required to

lubricate said engine,

lubricate said electric machine, and

lubricate said second electric machine.

7. The method of claim 6, wherein controlling said minimum line pressure of a hydraulic control system comprises:

monitoring a minimum line pressure required to operate other functions served by said hydraulic control system; and

selecting said minimum line pressure of a hydraulic control system based upon a larger pressure of said minimum line pressure for lubrication and said minimum line pressure required to operate other functions served by said hydraulic control system.

8. The method of claim 5, wherein controlling said minimum line pressure of a hydraulic control system comprises:

monitoring a minimum line pressure required to operate other functions served by said hydraulic control system; and

selecting said minimum line pressure of a hydraulic control system based upon the larger pressure of said minimum line pressure for lubrication and said minimum line pressure required to operate other functions served by said hydraulic control system.

9. Apparatus for controlling hydraulic line pressure for component lubrication in an electro-mechanical transmission mechanically-operatively coupled to an internal combustion engine and first and second electric machines, and adapted to selectively transmit mechanical power to an output member, said apparatus comprising:

a main hydraulic pump mechanically connected to said engine;

an electrically powered auxiliary hydraulic pump; and

a hydraulic control system operatively connected to said main hydraulic pump, said auxiliary hydraulic pump, and a lubrication circuit providing a flow of hydraulic oil to said engine, said first electric machine, and said second electric machine;

wherein said hydraulic control system includes logic monitoring a speed of said engine, a speed of said first electric machine, and a speed of a second electric machine, determining a minimum line pressure required for lubrication based upon said speeds, and controlling said main hydraulic pump and said auxiliary hydraulic pump based upon said minimum line pressure required for lubrication.

10. The apparatus of claim 9, wherein hydraulic control system comprises a circuit providing a substantially fixed flow resistance at a connection to said lubrication circuit.

11. The apparatus of claim 9, wherein hydraulic control system further includes logic controlling functions served by said hydraulic control system based upon said minimum line pressure required for lubrication.