Multiplexed control system and method for an electrically variable hybrid transmission

• US 20070117671A1
• Filed: 11/21/2005
• Published: 05/24/2007
• Est. Priority Date: 11/21/2005
• Status: Active Grant

• Current Assignee: Allison Transmission Incorporated (Allison Transmission Holdings Incorporated)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Foster, Michael, Long, Charles
• Granted Patent: US 7,396,306 B2
• Time in Patent Office: Days
• US Class Current: 475/116
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• 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 6/387 Actuated clutches, i.e. clutches engaged or disengaged by electric, hydraulic or mechanical actuating means
• CPC Class Codes: B60K 6/40 characterised by the assembly or relative disposition of components
• 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: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: F16H 2037/106 with switching means to provide two variator modes or ranges
• CPC Class Codes: F16H 2059/683 Sensing pressure in control systems or in fluid controlled devices, e.g. by pressure sensors for hydrostatic transmissions F16H2059/6861
• CPC Class Codes: F16H 61/0206 Layout of electro-hydraulic control circuits, e.g. arrangement of valves for control of actuators selecting and moving final output members, e.g. shift forks F16H61/2807
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A powertrain has an electrically variable hybrid transmission having an electro-hydraulic control system, plurality of electrical power units, and a plurality of torque transmitting mechanisms selectively engageable by the electro-hydraulic control system to provide four forward speed ranges, a neutral condition, an electric low and high speed mode, and an electrically variable low and high speed mode. Additionally, the electrically variable hybrid transmission provides a parallel reverse mode and a series reverse mode. The present invention provides an improved electro-hydraulic control system having a multiplexed electronic transmission range selection (ETRS) and reverse dog clutch system for an electrically variable hybrid transmission. The multiplexed control system of the present invention allows effective control of both the ETRS system and reverse dog clutch system using only one solenoid valve.

Claims

1. A control system for an electrically variable hybrid transmission comprising:

a multiplex valve;

a solenoid valve operable to selectively provide fluid pressure to said multiplex valve;

an electronic transmission range selection valve in selective fluid communication with said multiplex valve; and

a dog clutch relay valve in selective fluid communication with said multiplex valve.

2. The control system for an electrically variable hybrid transmission of claim 1, wherein said multiplex valve is operable to selectively distribute fluid pressure from said solenoid valve to said electronic transmission range selection valve or said dog clutch relay valve.

3. The control system for an electrically variable hybrid transmission of claim 1, wherein said multiplex valve is a boost valve.

4. The control system for an electrically variable hybrid transmission of claim 1, further comprising:

a spring engaged dog clutch in selective fluid communication with said dog clutch relay valve, and operable to provide a series electrically variable transmission mode of operation when said dog clutch is disengaged.

5. The control system for an electrically variable hybrid transmission of claim 4, wherein said dog clutch is selectively disengaged by fluid pressure from said dog clutch relay valve.

6. The control system for an electrically variable hybrid transmission of claim 1, further comprising:

a park pawl mechanism, wherein said electronic transmission range selection valve is operable to engage and disengage said park pawl mechanism.

7. The control system for an electrically variable hybrid transmission of claim 6, wherein said park pawl mechanism is engaged and disengaged by a servo, said servo being operable to selectively receive pressurized fluid from said electronic transmission range selection valve.

8. The control system for an electrically variable hybrid transmission of claim 1, further comprising:

a main passage with pressurized fluid disposed therein, said pressurized fluid being operable to latch said electronic transmission range selection valve in a pressure set position in all modes of transmission operation other than park.

9. The control system for an electrically variable hybrid transmission of claim 1, wherein said multiplex valve has a spring set position and a pressure set position, said multiplex valve being operable to distribute pressurized fluid from said solenoid valve to said electronic transmission range selection valve when in said spring set position, and said multiplex valve being operable to distribute pressurized fluid from said solenoid valve to said dog clutch relay valve when in said pressure set position.

10. A method of controlling an electronic transmission range selection valve and a dog clutch relay valve comprising:

providing a solenoid valve operable to provide a control pressure to the electronic transmission range selection valve and the dog clutch relay valve;

providing a multiplex valve in selective fluid communication with the electronic transmission range selection valve and the dog clutch relay valve and operable to selectively direct said control pressure to the electronic transmission range selection valve and the dog clutch relay valve;

controlling said multiplex valve to direct said control pressure to the electronic transmission range selection valve when said multiplex valve is in a first position; and

controlling said multiplex valve to direct said control pressure to the dog clutch relay valve when said multiplex valve is in a second position.

11. The method of claim 10, wherein said mutiplex valve is a boost valve.

12. The method of claim 10, wherein said first position is a spring set position and said second position is a pressure set position.

13. A control system for an electrically variable hybrid transmission comprising:

a boost valve;

a solenoid valve operable to selectively provide fluid pressure to said boost valve;

an electronic transmission range selection valve in selective fluid communication with said boost valve;

a dog clutch relay valve in selective fluid communication with said boost valve; and

wherein said boost valve has a spring set position and a pressure set position, said boost valve being operable to distribute pressurized fluid from said solenoid valve to said electronic transmission range selection valve when in said spring set position, and said boost valve being operable to distribute pressurized fluid from said solenoid valve to said dog clutch relay valve when in said pressure set position.

14. The control system for an electrically variable hybrid transmission of claim 13, further comprising:

a spring engaged dog clutch in selective fluid communication with said dog clutch relay valve, and operable to provide a series electrically variable transmission mode of operation when said dog clutch is disengaged.

15. The control system for an electrically variable hybrid transmission of claim 14, wherein said dog clutch is selectively disengaged by fluid pressure from said dog clutch relay valve.

16. The control system for an electrically variable hybrid transmission of claim 13, further comprising:

a park pawl mechanism, wherein said electronic transmission range selection valve is operable to engage and disengage said park pawl mechanism.

17. The control system for an electrically variable hybrid transmission of claim 16, wherein said park pawl mechanism is engaged and disengaged by a servo, said servo being operable to selectively receive pressurized fluid from said electronic transmission range selection valve.