Control apparatus for controlling intake air flow, fuel injection amount, and ignition timing at each cylinder of a multi-cylinder engine
AssigneeHitachi Automotive Systems, Ltd.
InventorsShinji Nakagawa, Kazuhiko Kanetoshi, Takanobu Ichihara, Minoru Ohsuga
Life of this patent
Estimating the term…
Abstract
An engine control apparatus having a unit for calculating the mean value of the angular acceleration with respect to each cylinder; a unit for calculating the variance of the angular acceleration with respect to each cylinder; a unit for estimating the torque and the air/fuel ratio with respect to each cylinder on the basis of the mean value and the variance; and a unit for controlling at least one of the intake air amount, the fuel injection amount and the ignition timing with respect to each cylinder on the basis of the estimated torque and air/fuel ratio.
Claims16
A control apparatus for an engine provided with a plurality of cylinders, comprising:
- a unit for calculating a mean value of an angular acceleration with respect to each cylinder;
- a unit for calculating a dispersion of the angular acceleration with respect to each cylinder;
- a unit for estimating a torque and an air/fuel ratio, with respect to each cylinder on the basis of the mean value of the angular acceleration and the dispersion of the angular acceleration;
- and
- a unit for controlling an intake air amount and/or a fuel injection amount and/or an ignition timing, with respect to each cylinder on the basis of the estimated torque and the estimated air/fuel ratio;
- wherein the unit for estimating the torque and the air/fuel ratio of each cylinder specifies the cylinder of which the mean value of the angular acceleration is minimum, and judges that the torque of the specified cylinder is smaller than the torque of any other cylinders and that the air/fuel ratio of the specified cylinder is comparable with the air/fuel ratios of all the other cylinders, when the mean value of the angular acceleration of the specified cylinder is not greater than a predetermined value A1 and when the dispersion of the angular acceleration of the specified cylinder is smaller than a predetermined value B1;
- wherein, when it is judged that the torque of the specified cylinder is smaller than the torques of any other cylinder and the air/fuel ratio of the specified cylinder is comparable with the air/fuel ratios of all the other cylinders, the unit for controlling the intake air amount and/or the fuel injection amount and/or the ignition timing corrects the intake air amount of the specified cylinder to be increased until the mean value of the angular acceleration of the specific cylinder becomes greater than the predetermined value A1, and also corrects the fuel injection amount of the specific cylinder to also be increased so as to keep the air/fuel ratio of the specific cylinder in accordance with the increased intake air amount;
- wherein the unit for estimating the torque and the air/fuel ratio of each cylinder specifies the cylinder of which the dispersion of the angular acceleration is maximum, and judges that the torque of the specified cylinder is comparable with the torques of all the other cylinders and that the air/fuel ratio of the specified cylinder is lean as compared with the air/fuel ratios of all the other cylinders, when the mean value of the angular acceleration of the specified cylinder is greater than the predetermined value A1 and smaller than a predetermined value A2 and when the dispersion of the angular acceleration of the specified cylinder is not smaller than the predetermined value B1;
- wherein, when it is judged that the torque of the specified cylinder is comparable with the torques of all the other cylinders and that the air/fuel ratio of the specified cylinder is lean, the intake air amount of the specified cylinder is corrected to be decreased until the dispersion of the angular acceleration of the specific cylinder becomes smaller than the predetermined value B1.
Dependencies are inferred from the claim text.