Automatic engine stop and restart mode for reducing emissions of a hybrid electric vehicle

• US 6,832,148 B1
• Filed: 10/14/2003
• Issued: 12/14/2004
• Est. Priority Date: 10/14/2003
• Status: Active Grant

• Current Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.), GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Hubbard, Gregory A., Bennett, Adam C., Sah, Jyjen F.
• Primary Examiner(s): Camby, Richard M.
• Application Number:
  US10/686,015
• Time in Patent Office: 427 Days
• Field of Search: 180/65.2, 180/65.3, 180/65.4, 180/65.8, 701/54, 701/36, 701/51, 701/70, 701/84, 607/06, 607/16, 607/18, 477/2, 477/3
• US Class Current: 701/54
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• 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: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60L 2250/26 by pedal actuation
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60W 10/06 including control of combustion engines
• 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 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2050/0054 Cut-off filters, retarders, delaying means, dead zones, threshold values or cut-off frequency
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2710/0616 : Position of fuel or air injector
• CPC Class Codes: B60W 2710/0644 : Engine speed
• CPC Class Codes: F02D 41/123 : the fuel injection being cut-off
• CPC Class Codes: F16H 2037/106 : with switching means to provide two variator modes or ranges
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

This novel silent operating mode for a hybrid electric vehicle (HEV) reduces noise and emissions compared to traditional HEV operating modes. It is a complementary series of software control functions that allows the vehicle to operate with reduced noise and emissions where specifically needed, while phasing-in engine power where allowed. The method utilizes an energy storage system budget associated with a modal quantity of energy allocated for the mode, and is adapted to automatically adjust the operation of the vehicle to accommodate deviations from the budgeted energy amount. The mode also adjusts the vehicle operation in conjunction with changes in the parametric conditions of the ESS.

Claims

1. A method of providing an engine stop mode of operation for a hybrid electric vehicle having an engine that is operatively and selectively coupled to an electric drive motor and transmission, comprising the steps of:

(1) defueling the engine and maintaining rotation of the engine by rotation of the electric drive motor at a vehicle speed that is less than a vehicle stop threshold value; and

(2) decoupling the engine and transmission in response to a first predetermined vehicle operating condition and stopping the rotation of the engine using the electric drive motor to apply a torque to oppose the rotation of the engine.

2. The method of claim 1, further comprising the steps of:

(3) restarting rotation of the engine in response to a second predetermined vehicle operating condition using the electric drive motor; and

(4) recoupling the engine and transmission.

3. The method of claim 2, further comprising the step of:

(5) refueling the engine at a vehicle speed that is greater than a vehicle start threshold value.

4. The method of claim 1, wherein the first predetermined vehicle operating condition is an open vehicle door.

5. The method of claim 2, wherein the second predetermined vehicle operating condition is a closed vehicle door.

6. The method of claim 1, wherein the vehicle stop threshold value is a function of a battery budget factor.

7. The method of claim 2, wherein the vehicle restart threshold value is a function of a battery budget factor.

8. A method of providing an engine stop and restart mode of operation for a hybrid electric vehicle having an engine that is operatively and selectively coupled to an electric drive motor and transmission, comprising the steps of:

(1) defueling the engine and maintaining rotation of the engine by rotation of the electric drive motor at a vehicle speed that is less than a vehicle stop threshold value;

(2) decoupling the engine and transmission in response to a first predetermined vehicle operating condition and stopping the rotation of the engine using the electric drive motor to apply a torque to oppose the rotation of the engine;

(3) restarting rotation of the engine in response to a second predetermined vehicle operating condition using the electric drive motor; and

(4) recoupling the engine and transmission.

9. The method of claim 8, further comprising the step of:

(5) refueling the engine at a vehicle speed that is greater than a vehicle start threshold value.

10. The method of claim 8, wherein the first predetermined vehicle operating condition is an open vehicle door and the second predetermined vehicle operating condition is a closed vehicle door.

11. The method of claim 8, wherein the vehicle stop threshold value and the vehicle restart threshold value are a function of a battery budget factor.

12. A method of providing an engine stop mode of operation for a hybrid electric vehicle having an engine that is operatively and selectively coupled to an electric drive motor and transmission, comprising the steps of:

(1) defueling the engine and maintaining a rotational speed of the engine by rotation of the electric drive motor at a vehicle speed that is less than a vehicle stop threshold value;

(2) initiating a motor off request in response to a first predetermined vehicle operating condition;

(3) commanding a neutral state of the engine and transmission, whereby the neutral state comprises selecting the operative decoupling of the engine from the transmission;

(4) confirming that the neutral state has been attained;

(5) stopping the rotation of the engine using the electric drive motor to apply a torque to oppose the rotation of the engine;

(6) initiating a motor on request in response to a second predetermined vehicle operating condition;

(7) restarting the rotation of the engine without fuel using the electric drive motor to apply a torque to the engine;

(8) commanding a range state of the engine and transmission, whereby the range state comprises selecting the operative coupling of the engine and transmission;

(9) commanding a vehicle speed to the electric drive motor, whereby if the vehicle speed command is greater than a vehicle restart threshold value, proceeding to step 10, and whereby if the vehicle speed is less than or equal to the vehicle restart threshold, returning to step 2;

(10) refueling the engine.

13. The method of claim 12, wherein the first predetermined vehicle operating condition is an open vehicle door.

14. The method of claim 12, wherein the second predetermined vehicle operating condition is a closed vehicle door.

15. The method of claim 12, wherein the vehicle stop threshold value is a function of a battery budget factor.

16. The method of claim 12, wherein the vehicle restart threshold value is a function of a battery budget factor.