AIR CONDITIONING TORQUE COMPENSATION ENERGY MATCHING INERTIA TRANSFER

• US 20090276130A1
• Filed: 04/10/2009
• Published: 11/05/2009
• Est. Priority Date: 05/02/2008
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Johnston, Mark E., Whitney, Christopher E., Shupe, Todd R.
• Granted Patent: US 8,406,954 B2
• Time in Patent Office: Days
• US Class Current: 701/68
• CPC Class Codes: B60H 1/3205 Control means therefor
• CPC Class Codes: B60H 1/322 for improving the stop or idling operation of the engine
• CPC Class Codes: B60H 2001/3273 related to the operation of the vehicle, e.g. the compressor driving torque
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 29/04 peculiar to engines driving pumps
• CPC Class Codes: F02D 41/0205 using an auxiliary engine speed control engine speed control per se F02D31/00
• CPC Class Codes: F02D 41/021 Introducing corrections for particular conditions exterior to the engine conjoint control of vehicle sub-units for propelling the vehicle B60W30/18

Abstract

An engine control system comprises a torque control module, an air conditioning (A/C) load comparison module, and an A/C load compensation module. The torque control module controls an engine to produce a first torque request based on a first torque maintains a current speed of the engine. The A/C load comparison module compares a transient load to a difference between a torque available to the engine and the first torque request. The A/C load compensation module selectively increases the first torque request prior to a clutch engagement based on the comparison.

Claims

1. An engine control system comprising:

a torque control module that controls an engine to produce a first torque request based on a first torque that maintains a current speed of said engine;

an air conditioning (A/C) load comparison module that compares a transient load to a difference between a torque available to said engine and said first torque request; and

an A/C load compensation module that selectively increases said first torque request prior to an A/C clutch engagement based on said comparison.

2. The engine control system of claim 1 wherein said A/C load compensation module increases said first torque request at a predetermined time before said A/C clutch engagement.

3. The engine control system of claim 1 wherein said first torque request remains increased for a predetermined period after said A/C clutch engagement.

4. The engine control system of claim 1 wherein said clutch engagement includes an air conditioning compressor, wherein said transient load is based on ambient temperature and head pressure.

5. The engine control system of claim 1 wherein said A/C load compensation module selectively increases said first torque request when said transient load is greater than said difference between said torque available to said engine and said first torque request.

6. The engine control system of claim 1 wherein said A/C load comparison module calculates a torque deficiency value when said transient load is greater than said difference between said torque available to said engine and said first torque request.

7. The engine control system of claim 6 wherein said A/C load compensation module increases said first torque request based on R=2DT/x², where R is an increase rate, D is said torque deficiency value, T is a time span of torque deficiency, and x is a predetermined period of time before said A/C clutch engagement.

8. The engine control system of claim 6 wherein said A/C load compensation module estimates an amount of energy missing during said A/C clutch engagement based on said torque deficiency value.

9. The engine control system of claim 8 wherein said A/C load compensation module increases said first torque request based on said amount of energy missing.

10. The engine control system of claim 9 wherein said A/C load compensation module estimates said amount of energy missing based on the product of said torque deficiency value, a time span of torque deficiency, and engine speed.

11. A torque compensation method comprising:

controlling an engine to produce a first torque request based on a first torque that maintains a current speed of said engine;

comparing a transient load to a difference between a torque available to said engine and said first torque request; and

selectively increasing said first torque request prior to an A/C clutch engagement based on said comparison.

12. The torque compensation method of claim 11 further comprising increasing said first torque request at a predetermined time before said A/C clutch engagement.

13. The torque compensation method of claim 11 further comprising maintaining said increased first torque request for a predetermined period after said A/C clutch engagement.

14. The torque compensation method of claim 11 wherein said clutch engagement includes an air conditioning compressor, wherein said transient load is based on ambient temperature and head pressure.

15. The torque compensation method of claim 11 further comprising selectively increasing said first torque request when said transient load is greater than said difference between said torque available to said engine and said first torque request.

16. The torque compensation method of claim 11 further comprising calculating a torque deficiency value when said transient load is greater than said difference between said torque available to said engine and said first torque request.

17. The torque compensation method of claim 16 further comprising increasing said first torque request based on R=2DT/x², where R is an increase rate, D is said torque deficiency value, T is a time span of torque deficiency, and x is a predetermined period of time before said A/C clutch engagement.

18. The torque compensation method of claim 16 further comprising estimating an amount of energy missing during said A/C clutch engagement based on said torque deficiency value.

19. The torque compensation method of claim 18 further comprising increasing said first torque request based on said amount of energy missing.

20. The torque compensation method of claim 19 further comprising estimating said amount of energy missing based on the product of said torque deficiency value, a time span of torque deficiency, and engine speed.