Internal-combustion engines – Charge forming device – Including means responsive to instantaneous change in engine...
Reexamination Certificate
2002-05-17
2003-12-02
Kwon, John T. (Department: 3747)
Internal-combustion engines
Charge forming device
Including means responsive to instantaneous change in engine...
C123S481000, C123S19800E
Reexamination Certificate
active
06655353
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to engine control systems for internal combustion engines, and more particularly to torque matching in a cylinder deactivation engine control system.
BACKGROUND OF THE INVENTION
Some internal combustion engines include engine control systems that deactivate cylinders under low load situations. For example, an eight cylinder can be operated using four cylinders to improve fuel economy by reducing pumping losses. Fuel economy improvement of approximately 5-10% can be realized.
To smoothly transition between activated and deactivated modes, the internal combustion engine must produce torque with a minimum of disturbances. Otherwise, the transition will not be transparent to the driver. In other words, excess torque will cause engine surge and insufficient torque will cause engine sag, which degrades the driving experience.
Conventional engine control systems that provide torque smoothing have been based on brake torque and as calibrated spark. Engine control systems using this approach does not account for changes in engine and environmental conditions. This approach also does not meet drivability specifications for maximum torque disturbances allowed during transitions between activated and deactivated modes.
SUMMARY OF THE INVENTION
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 desired pedal torque signal. An idle torque estimator generates a desired 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.
In other features, a first switch selects one of activated and deactivated modes for the torque loss estimator. A second switch selects one of activated and deactivated modes for the idle torque estimator. A position of the first and second switches is based on an operating mode of the engine.
In yet other features, a first summing circuit sums the desired brake torque signal and the torque loss signal for the deactivated mode. A first multiplier multiplies an output of the first summing circuit and an air per cylinder (APC) correction signal to produce a first desired deactivated indicated torque signal. A second multiplier multiplies the output of the first summing circuit and a throttle area correction signal to produce a second desired deactivated indicated torque signal. A second summing circuit sums the desired brake torque signal and the torque loss signal for the activated mode. A third multiplier multiplies an output of the second summing circuit and the APC correction signal to produce a first desired activated indicated torque signal. A fourth multiplier multiplies the output of the second summing circuit and the throttle area correction signal to produce a second desired activated indicated torque signal.
In still other features, a first desired APC estimator estimates a desired deactivated APC from the first deactivated desired indicated torque signal. A second desired APC estimator estimates a desired activated APC from the first desired activated indicated torque signal. A third switch communicates with the first and second desired APC estimators and selects one of the desired deactivated APC signal and the desired activated APC signal based on the operating mode of the engine.
In still other features, a first desired area estimator estimates a desired deactivated area from the second deactivated desired indicated torque signal. A second desired APC estimator estimates a desired deactivated area from the second activated desired indicated torque signal. A fourth switch communicates with the first and second desired area estimators and selects one of the desired deactivated area signal and the desired activated area signal based on the operating mode of the engine.
In still other features, the 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 receives the deactivated idle airflow signal and generates a deactivated idle torque signal. An activated idle torque estimator receives the activated idle airflow signal and generates an activated idle torque signal. A fifth switch selects one of the activated and deactivated idle airflow signals based on an operating mode of the engine.
REFERENCES:
patent: 5151861 (1992-09-01), Danno et al.
patent: 5374224 (1994-12-01), Huffmaster et al.
patent: 5398544 (1995-03-01), Lipinski et al.
patent: 5408966 (1995-04-01), Lipinski et al.
patent: 5408974 (1995-04-01), Lipinski et al.
patent: 5431139 (1995-07-01), Grutter et al.
patent: 5437253 (1995-08-01), Huffmaster et al.
patent: 5568795 (1996-10-01), Robichaux et al.
patent: 5769054 (1998-06-01), Schnaibel et al.
patent: 5992382 (1999-11-01), Bruedigam et al.
patent: 6035252 (2000-03-01), Dixon et al.
patent: 6081042 (2000-06-01), Tabata et al.
patent: 6226585 (2001-05-01), Cullen
patent: 6237563 (2001-05-01), Froehlich et al.
patent: 6373144 (2002-04-01), Frohlich et al.
patent: 6490511 (2002-12-01), Raftari et al.
patent: 0731265 (1996-09-01), None
Watanabe/Fukutani, SAE Technical Paper Series 820156, Cylinder Cutoff of 4-Stroke Cycle Engines at Part-Load and Idle, Feb. 22-26, 1982.
DeVries Christopher
General Motors Corporation
Kwon John T.
LandOfFree
Cylinder deactivation engine control system with torque... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cylinder deactivation engine control system with torque..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cylinder deactivation engine control system with torque... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3165967