Hybrid Vehicle Engine Starter Systems And Methods

• US 20170334422A1
• Filed: 05/19/2016
• Published: 11/23/2017
• Est. Priority Date: 05/19/2016
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Namuduri, Chandra S., Hao, Lei, Gopalakrishnan, Suresh, Nehl, Thomas W.
• Granted Patent: US 10,293,804 B2
• Time in Patent Office: Days
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 2006/4825 Electric machine connected or connectable to gearbox input shaft
• CPC Class Codes: B60K 6/26 characterised by the motors or the generators
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60K 6/48 Parallel type
• 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 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• 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 2540/10 Accelerator pedal position
• CPC Class Codes: B60Y 2200/92 Hybrid vehicles
• CPC Class Codes: B60Y 2300/182 Selecting between different operative modes, e.g. comfort and performance modes
• CPC Class Codes: B60Y 2300/192 Power-up or power-down of the driveline, e.g. start up of a cold engine
• CPC Class Codes: B60Y 2300/43 Control of engines
• CPC Class Codes: B60Y 2300/60 Control of electric machines, e.g. problems related to electric motors or generators
• CPC Class Codes: B60Y 2300/63 Starter motor mode
• CPC Class Codes: B60Y 2400/60 Electric Machines, e.g. motors or generators
• CPC Class Codes: F02N 11/00 Starting of engines by means of electric motors
• CPC Class Codes: F02N 11/006 using a plurality of electric motors
• CPC Class Codes: F02N 11/0814 comprising means for controlling automatic idle-start-stop
• CPC Class Codes: F02N 11/0862 : characterised by the electrical power supply means, e.g. battery
• CPC Class Codes: F02N 2200/101 : Accelerator pedal position
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y10S 903/906 : Motor or generator
• CPC Class Codes: Y10S 903/93 : Conjoint control of different elements

Abstract

A vehicle propulsion system includes an engine and a first electric machine each configured to selectively provide torque to propel the vehicle. The propulsion system also includes a second electric machine coupled to the engine and configured to start the engine from an inactive state. A high-voltage battery powers both of the first electric machine and the second electric machine over a high-voltage bus. The vehicle further includes a controller programmed to issue a command to start the engine using the second electric machine in response to a threshold acceleration demand following a period of reduced acceleration demand.

Claims

1. A vehicle propulsion system comprising:

an engine and a first electric machine each configured to selectively provide torque to propel the vehicle;

a second electric machine coupled to the engine and configured to start the engine from an inactive state;

a high-voltage battery to power both of the first electric machine and the second electric machine over a high-voltage bus; and

a controller programmed to issue a command to start the engine using the second electric machine in response to a threshold acceleration demand following a period of reduced acceleration demand.

2. The vehicle propulsion system of claim 1 wherein the second electric machine is a brushless permanent magnet motor with an electronic commutator comprising solid state switches and an electric machine controller.

3. The vehicle propulsion system of claim 1 wherein the high-voltage bus is powered at about 48 volts.

4. The vehicle propulsion system of claim 1 further comprising a low-voltage battery configured to power at least one vehicle accessory over a low-voltage bus.

5. The vehicle propulsion system of claim 1 wherein the controller is further programmed to deactivate the engine in response to a coast condition corresponding to substantially zero acceleration demand while the vehicle is moving.

6. The vehicle propulsion system of claim 1 wherein the second electric machine is provided with a single solenoid actuator to selectively couple the second electric machine to the engine, and the second electric machine is connected to the high-voltage battery via solid-state switches.

7. A method of allocating sources of vehicle propulsion comprising:

providing a powertrain having an engine and a first electric machine configured to selectively provide vehicle propulsion;

deactivating the engine in response to an acceleration demand less than a predetermined shutoff threshold; and

in response to the acceleration demand increasing to greater than a predetermined restart threshold, reactivating the engine using a second electric machine coupled to the engine wherein the second electric machine is powered over a high-voltage bus.

8. The method of claim 7 wherein the engine is deactivated during a vehicle rolling coast condition.

9. The method of claim 7 further comprising supplying power to both of the first electric machine and the second electric machine from a high-voltage battery.

10. The method of claim 7 further comprising synchronizing a rotational speed of the second electric machine with a speed of the engine during an engine restart event.

11. The method of claim 10 wherein the rotational speed of the second electric machine is synchronized prior to mechanically engaging the second electric machine to the engine.

12. The method of claim 7 wherein the predetermined restart threshold is greater than the predetermined shutoff threshold.

13. A vehicle propulsion system comprising:

a high-voltage power source;

an electric machine capable of selectively propelling the vehicle using power from the high-voltage power source;

an engine capable of selectively propelling the vehicle;

a brushless permanent magnet motor powered by the high-voltage power source and configured to couple to the engine and restart the engine from a deactivated state; and

a controller programmed to

deactivate the engine in response to an acceleration demand less than a first threshold,

operate the brushless permanent magnet motor in response to an acceleration demand greater than a second threshold while the engine is in a deactivated state,

synchronize a speed of the brushless permanent magnet motor with a speed of the engine, and

engage the brushless permanent magnet motor with the engine to restart the engine.

14. The vehicle propulsion system of claim 13 further comprising a low-voltage battery configured to power at least one vehicle accessory over a low-voltage bus.

15. The vehicle propulsion system of claim 13 wherein the controller is further programmed to deactivate the engine in response to a coast condition corresponding to substantially zero acceleration demand while the vehicle is rolling.

16. The vehicle propulsion system of claim 13 wherein the controller is further programmed to deactivate the engine in response to a standstill condition corresponding to substantially zero acceleration demand.

17. The vehicle propulsion system of claim 13 wherein the second threshold is greater than the first threshold.

18. The vehicle propulsion system of claim 13 wherein the brushless permanent magnet motor is provided with a single solenoid actuator to selectively couple the brushless permanent magnet motor to the engine, and the brushless permanent magnet motor is connected to the high-voltage power source via solid-state switches.

19. The vehicle propulsion system of claim 13 wherein brushless permanent magnet motor includes an integrated circuit to perform electronic commutation of the solid-state switches in conjunction with a rotor position sensor to convert direct current from the high-voltage power source into alternating current to drive the brushless permanent magnet motor.