Cylinder deactivation engine control system with torque matching

• US 6,655,353 B1
• Filed: 05/17/2002
• Issued: 12/02/2003
• Est. Priority Date: 05/17/2002
• Status: Expired due to Term

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: General Motors Corporation (General Motors Company)
• Inventors: Rayl, Allen B.
• Primary Examiner(s): KWON, JOHN
• Application Number:
  US10/150,883
• Publication Number:
  US 20030213469A1
• Time in Patent Office: 564 Days
• Field of Search: 123/198.F, 123/481, 123/352, 123/361, 123/436
• US Class Current: 123/436
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04
• CPC Class Codes: F02D 2200/1004 Estimation of the output torque
• 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 2250/21 during a transition between engine operation modes or states
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/083 taking into account engine load variation, e.g. air-conditionning

Abstract

An engine control system and method smoothes torque during transitions in a displacement on demand engine. A torque loss estimator generates a torque loss signal based on torque loss due to at least one of friction, pumping and accessories. A pedal torque estimator generates a pedal torque signal. An idle torque estimator generates an idle torque signal. A summing circuit generates a difference between the pedal torque signal and the idle torque and the torque loss signals and outputs a desired brake torque signal.

Claims

1. An engine control system for smoothing torque during transitions in a displacement on demand engine, comprising:

a torque loss estimator that generates a torque loss signal based on torque loss due to at least one of friction, pumping and accessories;

a pedal torque estimator that generates a desired pedal torque signal;

an idle torque estimator that generates a desired idle torque signal; and

a summing circuit that generates a difference between said pedal torque signal and said idle torque and said torque loss signals and that outputs a desired brake torque signal.

2. The engine control system of claim 1 further comprising:

a first switch that selects one of activated and deactivated modes for said torque loss estimator.

3. The engine control system of claim 1 further comprising:

a second switch that selects one of activated and deactivated modes for said idle torque estimator.

4. The engine control system of claim 3 wherein a position of said first and second switches is based on an operating mode of said engine.

5. The engine control system of claim 4 further comprising:

a first summing circuit that sums said desired brake torque signal and said torque loss signal for said deactivated mode; and

a first multiplier that multiplies an output of said first summing circuit and an air per cylinder (APC) correction signal to produce a first desired deactivated indicated torque signal.

6. The engine control system of claim 5 further comprising:

a second multiplier that multiplies said output of said first summing circuit and a throttle area correction signal to produce a second desired deactivated indicated torque signal.

7. The engine control system of claim 6 further comprising:

a second summing circuit that sums said desired brake torque signal and said torque loss signal for said activated mode; and

a third multiplier that multiplies an output of said second summing circuit and said APC correction signal to produce a first desired activated indicated torque signal.

8. The engine control system of claim 7 further comprising:

a fourth multiplier that multiplies said output of said second summing circuit and said throttle area correction signal to produce a second desired activated indicated torque signal.

9. The engine control system of claim 8 further comprising:

a first desired APC estimator that estimates a desired deactivated APC from said first deactivated desired indicated torque signal;

a second desired APC estimator that estimates a desired activated APC from said first desired activated indicated torque signal; and

a third switch that communicates with said first and second desired APC estimators and that selects one of said desired deactivated APC signal and said desired activated APC signal based on said operating mode of said engine.

10. The engine control system of claim 9 further comprising:

a first desired area estimator that estimates a desired deactivated area from said second deactivated desired indicated torque signal;

a second desired APC estimator that estimates a desired deactivated area from said second activated desired indicated torque signal; and

a fourth switch that communicates with said first and second desired area estimators and that selects one of said desired deactivated area signal and said desired activated area signal based on said operating mode of said engine.

11. The engine control system of claim 1 wherein said idle airflow estimator includes:

an idle air per cylinder estimator that generates idle airflow signals for activated and deactivated modes based on engine rpm and idle airflow;

a deactivated idle torque estimator that receives said deactivated idle airflow signal and that generates a deactivated idle torque signal;

an activated idle torque estimator that receives said activated idle airflow signal and that generates an activated idle torque signal; and

a fifth switch that selects one of said activated and deactivated idle airflow signals based on an operating mode of said engine.

12. The engine control system of claim 1 wherein said pedal torque estimator generates said desired pedal torque signal based on engine rpm and non-idle throttle area.

13. The engine control system of claim 1 wherein said torque loss estimator includes:

a deactivated vacuum estimator that generates a deactivated vacuum estimate signal based on activated vacuum;

an activated vacuum estimator that generates an activated vacuum estimate signal based on deactivated vacuum;

a sixth switch that selects one of vacuum and said deactivated vacuum estimate based on an operating mode of said engine;

a seventh switch that selects one of vacuum and said activated vacuum estimate based on said operating mode of said engine;

a deactivated pumping torque estimator that generates a deactivated pumping torque signal based on an output of said sixth switch;

a first hold circuit that holds said deactivated pumping torque signal;

an activated pumping torque estimator that estimates activated pumping torque based on an output of said seventh switch;

a second hold circuit that holds said activated pumping torque signal; and

an eighth switch that selects one of said deactivated and said activated pumping torque signal.

14. A method for smoothing torque during transitions in a displacement on demand engine, comprising:

generating a torque loss signal based on torque loss due to at least one of friction, pumping and accessories;

generating a desired pedal torque signal;

generating a desired idle torque signal; and

generating a difference between said desired pedal torque signal and said desired idle torque and said torque loss signals to provide a desired brake torque signal.

15. The method of claim 14 further comprising:

selecting one of activated and deactivated modes for said torque loss estimator based on an operating mode of said engine.

16. The method of claim 14 further comprising:

selecting one of activated and deactivated modes for said idle torque estimator based on an operating mode of said engine.

17. The method of claim 16 further comprising:

summing said desired brake torque signal and said torque loss signal for said deactivated mode to provide a first sum; and

multiplying said first sum and an air per cylinder (APC) correction signal to produce a first desired deactivated indicated torque signal.

18. The method of claim 17 further comprising:

multiplying said first sum and a throttle area correction signal to produce a second desired deactivated indicated torque signal.

19. The method of claim 18 further comprising:

summing said desired brake torque signal and said torque loss signal for said activated mode to provide a second sum; and

multiplying said second sum and said APC correction signal to produce a first desired activated indicated torque signal.

20. The method of claim 19 further comprising:

multiplying said second sum and said throttle area correction signal to produce a second desired activated indicated torque signal.

21. The method of claim 20 further comprising:

estimating a desired deactivated APC from said first deactivated desired indicated torque signal;

estimating a desired activated APC from said first desired activated indicated torque signal; and

selecting one of said desired deactivated APC signal and said desired activated APC signal based on said operating mode of said engine.

22. The method of claim 21 further comprising:

estimating a desired deactivated area from said second deactivated desired indicated torque signal;

estimating a desired deactivated area from said second activated desired indicated torque signal; and

selecting one of said desired deactivated area signal and said desired activated area signal based on said operating mode of said engine.

23. The method of claim 14 wherein estimating said idle airflow includes:

generates idle airflow signals for activated and deactivated modes based on engine rpm and idle airflow;

generating a deactivated idle torque signal based on said deactivated idle airflow signal;

generating an activated idle torque signal based on said activated idle airflow signal; and

selecting one of said activated and deactivated idle airflow signals based on an operating mode of said engine.

24. The method of claim 14 further comprising generating said desired pedal torque signal based on engine rpm and non-idle throttle area.

25. The method of claim 24 wherein generating said torque loss signal includes:

generating a deactivated vacuum estimate signal based on activated vacuum;

generating an activated vacuum estimate signal based on deactivated vacuum;

using a sixth switch to selects one of vacuum and said deactivated vacuum estimate based on an operating mode of said engine;

using a seventh switch to selects one of vacuum and said activated vacuum estimate based on said operating mode of said engine;

generating a deactivated pumping torque signal based on an output of said sixth switch;

holding said deactivated pumping torque signal;

estimating activated pumping torque based on an output of said seventh switch;

holding said activated pumping torque signal; and

using an eighth switch to selects one of said deactivated and said activated pumping torque signal.