Engine on idle arbitration for a hybrid electric vehicle

• US 6,664,651 B1
• Filed: 11/14/2000
• Issued: 12/16/2003
• Est. Priority Date: 11/14/2000
• Status: Expired due to Term

• Current Assignee: Siemens Dematic Corp. (Siemens AG)
• Original Assignee: Ford Motor Company
• Inventors: Ramaswamy, Deepa, Breida, Mary Theresa, Kotre, Stephen John, Woestman, Joanne Theresa
• Primary Examiner(s): Ramirez, Nestor
• Assistant Examiner(s): Mohandesi, Iraj A.
• Application Number:
  US09/712,436
• Time in Patent Office: 1,127 Days
• Field of Search: 290/29, 290/40.R, 290/40.C, 290/40.B, 290/34
• US Class Current: 290/29
• 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 2240/441 Speed
• 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 10/26 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 2050/021 Means for detecting failure or malfunction
• 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 2510/068 Engine exhaust temperature
• CPC Class Codes: B60W 2510/069 Engine braking signal
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2710/065 Idle condition
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: F02D 2250/24 by using an external load, e.g. a generator
• CPC Class Codes: F02D 2250/41 Control to generate negative pressure in the intake manifold, e.g. for fuel vapor purging or brake booster
• CPC Class Codes: F02D 41/003 : Adding fuel vapours, e.g. drawn from engine fuel reservoir
• CPC Class Codes: F02D 41/042 : for stopping the engine
• CPC Class Codes: F02D 41/083 : taking into account engine load variation, e.g. air-conditionning
• CPC Class Codes: F02D 41/16 : for idling
• CPC Class Codes: F02D 41/2454 : Learning of the air-fuel ratio control
• CPC Class Codes: F02N 11/0829 : related to special engine control, e.g. giving priority to engine warming-up or learning
• CPC Class Codes: F02N 11/084 : State of vehicle accessories, e.g. air condition or power steering
• CPC Class Codes: F02N 2200/023 : Engine temperature
• CPC Class Codes: F02N 2200/026 : Catalyst temperature
• CPC Class Codes: F02N 2200/061 : Battery state of charge [SOC]
• CPC Class Codes: F02N 2200/0801 : Vehicle speed
• CPC Class Codes: F02N 2200/0806 : Air condition state
• CPC Class Codes: F02N 2200/0807 : Brake booster state
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y10S 903/903 : having energy storing means, e.g. battery, capacitor

Abstract

This invention is a method and system for determining whether the engine should be running in a Hybrid Electric Vehicle during vehicle idle conditions. Specifically, a controller determines if the vehicle is in idle and if engine operation is necessary. To determine whether engine operation is necessary, the controller determines whether the battery needs charging, whether vacuum needs to be replaced in the climate control system or brake system reservoir, whether the vapor canister requires purging, whether the adaptive fuel tables require fast adapting, whether the engine or catalyst temperatures are unacceptable, or whether the air conditioning has been requested. Once the controller determines that the engine must be running, the controller determines in which control mode to run the engine, either speed control mode (using powertrain controllers) or torque control mode (using a generator and generator controller). Finally, the controller optimizes engine running conditions, to the extent possible depending upon the control mode, to perform any necessary functions during vehicle idle.

Claims

1. A method for controlling idle speed of an engine in a hybrid electric vehicle, the vehicle including a battery, a generator operatively coupled to the engine, an engine controller, and a vehicle system controller, the method comprising:

determining whether a set of vehicle idle entry conditions are met, the idle entry conditions being met when the vehicle speed is below a predetermined value and an accelerator pedal is below a predetermined minimum pedal position;

selectively activating the vehicle system controller to control the generator to control engine idle speed when any one of a predetermined first set of operating conditions is present;

selectively activating the engine controller to control engine idle speed when a predetermined second set of operating conditions is present; and

turning off the engine when both the predetermined first set of conditions is not present and the engine has been in a current vehicle idle mode for a predetermined amount of time.

2. The method of claim 1, wherein the vehicle system controller is selectively activated to control engine idle speed when a battery state of charge is below a predetermined minimum value.

3. The method of claim 1, wherein the vehicle further includes a climate control reservoir, and the vehicle system controller is selectively activated to control engine idle speed when a vacuum in the climate control reservoir is below a predetermined minimum level.

4. The method of claim 1, wherein the vehicle further includes a brake system reservoir, and the vehicle system controller is selectively activated to control engine idle speed when a vacuum in the brake system reservoir is below a predetermined minimum level.

5. The method of claim 1, wherein the vehicle further includes a vapor canister, and the vehicle system controller is selectively activated to control engine idle speed when the vapor canister requires purging.

6. The method of claim 1, wherein the vehicle further includes an adaptive fuel table, and the vehicle system controller is selectively activated to control engine idle speed when the adaptive fuel table requires fast adaptive learning.

7. The method of claim 1, wherein the vehicle system controller is selectively activated to control engine idle speed when the engine has cooled below a predetermined level.

8. The method of claim 1, wherein the vehicle further comprises a catalyst, and the vehicle system controller is selectively activated to control the engine idle speed when the catalyst has cooled below a predetermined level.

9. The method of claim 1, wherein the vehicle system controller is selectively activated to control engine idle speed when air conditioning has been requested by a vehicle operator.

10. The method of claim 1, wherein the vehicle system controller is selectively activated to control engine idle speed when the generator has failed or a battery state of charge exceeds a predetermined maximum level.

12. The method of claim 1, wherein the predetermined first set of operating conditions comprises a low battery state of charge, a low climate control vacuum level, a low brake system reservoir vacuum level, a high fuel tank pressure, the existence of a minimum time period since a last vapor canister purging, the existence of current vapor canister purging, the existence of a learned adaptive fuel table for the current driving mode, a low engine temperature, a low catalyst temperature, and the state of activation of an air conditioning switch.

13. The method of claim 1, wherein the predetermined second set of operating conditions comprises a high battery state of charge and a failed generator.

11. A hybrid electric vehicle including a generator having a rotor assembly operatively coupled to an engine, the hybrid electric vehicle comprising:

a vehicle system controller for controlling idle speed of the engine when a battery state of charge is below a predetermined level and the generator has not failed; and

an engine controller for controlling the idle speed of the engine when the battery state of charge exceeds a predetermined maximum level or the generator fails.

14. A method for controlling idle speed of an engine in a hybrid electric vehicle, the vehicle including a battery, a generator operatively coupled to the engine, an engine controller, and a vehicle system controller, the method comprising:

determining whether a set of vehicle idle entry conditions are met, the idle entry conditions being met when the vehicle speed is below a predetermined value and an accelerator pedal is below a predetermined minimum pedal position;

selectively activating the vehicle system controller to control the generator to control engine idle speed when any one of a predetermined first set of operating conditions is present, the first set of operating conditions including a low battery state of charge, a low climate control vacuum level, a low brake system reservoir vacuum lever, a high fuel tank pressure, the existence of a minimum time period since a last vapor canister purging, the existence of current vapor canister purging, the existence of a learned adaptive fuel table for the current driving mode, a low engine temperature, a low catalyst temperature, and the state of activation of an air conditioning switch;

selectively activating the engine controller to control engine idle speed when a predetermined second set of operating conditions is present; and

turning off the engine when both the predetermined first set of conditions is not present and the engine has been in a current vehicle idle mode for a predetermined amount of time.

15. The method of claim 14, wherein the predetermined second set of operating conditions comprises a high battery state of charge and a failed generator.

16. A method for controlling idle speed of an engine in a hybrid electric vehicle, the vehicle including a battery, a generator operatively coupled to the engine, an engine controller, and a vehicle system controller, the method comprising:

determining whether a set of vehicle idle entry conditions are met, the idle entry conditions being met when the vehicle speed is below a predetermined value and an accelerator pedal is below a predetermined minimum pedal position;

selectively activating the vehicle system controller to control the generator to control engine idle speed when any one of a predetermined first set of operating conditions is present;

selectively activating the engine controller to control engine idle speed when a predetermined second set of operating conditions is present, the predetermined second set of operating conditions including a high battery state of charge and a failed generator; and

turning off the engine when both the predetermined first set of conditions is not present and the engine has been in a current vehicle idle mode for a predetermined amount of time.