Method for compensating for accessory loading

• US 7,295,915 B1
• Filed: 05/01/2006
• Issued: 11/13/2007
• Est. Priority Date: 05/01/2006
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Okubo, Shunsuke, Syed, Fazal
• Primary Examiner(s): Cronin; Stephen K.
• Assistant Examiner(s): Hoang; Johnny H.
• Application Number:
  US11/381,008
• Publication Number:
  US 20070255488A1
• Time in Patent Office: 561 Days
• Field of Search: 701/101, 701/102, 701/107, 701110-115, 180 652- 656, 123/179.3, 123/179.4
• US Class Current: 701/110
• CPC Class Codes: B60K 1/02 comprising more than one electric 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: B60W 10/06 including control of combustion engines
• 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 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/069 Engine braking signal
• CPC Class Codes: B60W 2555/20 Ambient conditions, e.g. wind or rain
• CPC Class Codes: F02D 2200/1006 Engine torque losses, e.g. friction or pumping losses or losses caused by external loads of accessories
• CPC Class Codes: F02D 41/083 taking into account engine load variation, e.g. air-conditionning
• CPC Class Codes: F02D 41/12 for deceleration F02D41/0005, F02D41/107 take precedence
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

An internal combustion engine includes an advanced vehicle system controller (VSC) that calculates a total power demand to meet a driver wheel power demand plus any accessory loads and independently schedules an engine speed and load operating point to meet the total power demand. A reduction in available engine brake power that is not associated with a driver input, and would ordinarily cause the VSC to respond by raising engine speed, is detected. The driver wheel power demand is reduced to compensate for the reduction in available engine brake power such that the VSC does not need to raise engine speed to meet the driver wheel power demand. A magnitude of the reduction may be determined according to a calibration map to allow a trade off to be made between driveability and noise, vibration, and harshness.

Claims

1. A method of controlling an internal combustion engine which includes an advanced vehicle system controller (VSC) that calculates a total power demand to meet a driver wheel power demand plus any accessory loads and independently schedules an engine speed and load operating point to meet the total power demand, the method comprising:

detecting a reduction in available engine brake power for meeting the driver wheel power demand that is not associated with a driver input and would ordinarily cause the VSC to respond by raising engine speed; and

reducing the driver wheel power demand to compensate for the reduction in available engine brake power such that the VSC does not need to raise engine speed to meet the driver wheel power demand.

2. The method of claim 1 wherein the reduction in available engine brake power is due to engagement of an accessory load.

3. The method of claim 2 wherein the accessory load comprises an air conditioning compressor.

4. The method of claim 1 wherein the engine includes a power split hybrid powertrain.

5. The method of claim 1 further comprising:

determining an existence of a wide open throttle condition; and

only reducing the driver wheel power demand when the wide open throttle condition exists and the reduction in available engine brake power is detected.

6. The method of claim 5 wherein determining the existence of the wide open throttle condition comprises:

determining whether or not additional throttle opening would increase available engine brake power.

7. The method of claim 1 further comprising:

only reducing the driver wheel power demand when a minimum vehicle speed threshold is met and the reduction in available engine brake power is detected.

8. The method of claim 1 further comprising:

only reducing the driver wheel power demand when a maximum driver demand power threshold is met and the reduction in available engine brake power is detected.

9. The method of claim 1 further comprising:

applying the driver wheel power demand reduction as a filtered driver wheel power demand reduction to prevent abrupt driver wheel power demand changes.

10. The method of claim 1 wherein a magnitude of the reduction is determined according to a calibration map.

11. An internal combustion engine which includes an advanced vehicle system controller (VSC) that calculates a total power demand to meet a driver wheel power demand plus any accessory loads and independently schedules an engine speed and load operating point to meet the total power demand, the VSC being programmed to:

detect a reduction in available engine brake power for meeting the driver wheel power demand that is not associated with a driver input and would ordinarily cause the VSC to respond by raising engine speed; and

reduce the driver wheel power demand to compensate for the reduction in available engine brake power such that the VSC does not need to raise engine speed to meet the driver wheel power demand.

12. The engine of claim 11 wherein the reduction in available engine brake power is due to engagement of an accessory load.

13. The engine of claim 12 wherein the accessory load comprises an air conditioning compressor.

14. The engine of claim 11 wherein the engine includes a power split hybrid powertrain.

15. The engine of claim 11 wherein the VSC is further programmed to:

determine an existence of a wide open throttle condition; and

only reduce the driver wheel power demand when the wide open throttle condition exists and the reduction in available engine brake power is detected.

16. The engine of claim 15 wherein determining the existence of the wide open throttle condition comprises:

determining whether or not additional throttle opening would increase available engine brake power.

17. The engine of claim 11 wherein the VSC is further programmed to:

only reduce the driver wheel power demand when a minimum vehicle speed threshold is met and the reduction in available engine brake power is detected.

18. The engine of claim 11 wherein the VSC is further programmed to:

only reduce the driver wheel power demand when a maximum driver demand power threshold is met and the reduction in available engine brake power is detected.

19. The engine of claim 11 wherein the VSC is further programmed to:

apply the driver wheel power demand reduction as a filtered driver wheel power demand reduction to prevent abrupt driver wheel power demand changes.

20. The engine of claim 11 wherein a magnitude of the reduction is determined according to a calibration map.