Abstract: A control apparatus calculates a exhaust gas air-fuel ratio of a plurality of cylinders, in which the operation angle of an intake valve is set to a predetermined operation angle, e.g., a maximum operation angle, based on a value output from an air-fuel ratio sensor so as to minimize a variation in an fuel injection quantity between the plurality of cylinders by that exhaust gas air-fuel ratio. That is, the exhaust gas air-fuel ratio of the plurality of cylinders, in which the valve opening characteristics of the intake valve and an exhaust valve are set such that the intake air amount to be introduced into the plurality of cylinders is limited by the opening amount of a throttle valve, for example, and not limited by the valve opening characteristics of the intake valve or the exhaust valve is calculated, and the variation in the fuel injection quantity among the plurality of cylinders is then reduced by that exhaust gas air-fuel ratio.

Abstract: A control apparatus calculates a exhaust gas air-fuel ratio of a plurality of cylinders, in which the operation angle of an intake valve is set to a predetermined operation angle, e.g., a maximum operation angle, based on a value output from an air-fuel ratio sensor so as to minimize a variation in an fuel injection quantity between the plurality of cylinders by that exhaust gas air-fuel ratio. That is, the exhaust gas air-fuel ratio of the plurality of cylinders, in which the valve opening characteristics of the intake valve and an exhaust valve are set such that the intake air amount to be introduced into the plurality of cylinders is limited by the opening amount of a throttle valve, for example, and not limited by the valve opening characteristics of the intake valve or the exhaust valve is calculated, and the variation in the fuel injection quantity among the plurality of cylinders is then reduced by that exhaust gas air-fuel ratio.

Abstract: A control apparatus calculates a exhaust gas air-fuel ratio of a plurality of cylinders, in which the operation angle of an intake valve is set to a predetermined operation angle, e.g., a maximum operation angle, based on a value output from an air-fuel ratio sensor so as to minimize a variation in an fuel injection quantity between the plurality of cylinders by that exhaust gas air-fuel ratio. That is, the exhaust gas air-fuel ratio of the plurality of cylinders, in which the valve opening characteristics of the intake valve and an exhaust valve are set such that the intake air amount to be introduced into the plurality of cylinders is limited by the opening amount of a throttle valve, for example, and not limited by the valve opening characteristics of the intake valve or the exhaust valve is calculated, and the variation in the fuel injection quantity among the plurality of cylinders is then reduced by that exhaust gas air-fuel ratio.

Abstract: A control device of a multicylinder internal combustion engine provided with a valve operating characteristic control means for controlling a valve operating characteristic of at least one of an intake valve and exhaust valve, which estimates an intake difference of cylinders and limits a control range of said valve operating characteristic in accordance with said estimated intake difference.

Abstract: A control apparatus calculates a exhaust gas air-fuel ratio of a plurality of cylinders, in which the operation angle of an intake valve is set to a predetermined operation angle, e.g., a maximum operation angle, based on a value output from an air-fuel ratio sensor so as to minimize a variation in an fuel injection quantity between the plurality of cylinders by that exhaust gas air-fuel ratio. That is, the exhaust gas air-fuel ratio of the plurality of cylinders, in which the valve opening characteristics of the intake valve and an exhaust valve are set such that the intake air amount to be introduced into the plurality of cylinders is limited by the opening amount of a throttle valve, for example, and not limited by the valve opening characteristics of the intake valve or the exhaust valve is calculated, and the variation in the fuel injection quantity among the plurality of cylinders is then reduced by that exhaust gas air-fuel ratio.

Abstract: An engine is provided with a variable valve mechanism capable of changing a degree of an operating angle and a phase of a valve-open period of an intake valve. A controller selectively executes at least one of a plurality of knock controls including a phase adjustment of the valve-open period of the intake valve when a knocking is detected by a knock sensor. When the operating angle of the intake valve is smaller than 180 degrees, a knock control is selected and executed such that a valve-open timing IVO of the intake valve does not exceed a predetermined timing (TDC+?) retarded from a top dead center TDC by a predetermined angle ?. Specifically, for example, when the operating angle is smaller than 180 degrees and the valve-open timing IVO of the intake valve is after the top dead center TDC, the valve-open timing IVO is advanced.

Abstract: An engine is provided with a variable valve mechanism capable of changing a degree of an operating angle and a phase of a valve-open period of an intake valve. A controller selectively executes at least one of a plurality of knock controls including a phase adjustment of the valve-open period of the intake valve when a knocking is detected by a knock sensor. When the operating angle of the intake valve is smaller than 180 degrees, a knock control is selected and executed such that a valve-open timing IVO of the intake valve does not exceed a predetermined timing (TDC+&agr;) retarded from a top dead center TDC by a predetermined angle &agr;. Specifically, for example, when the operating angle is smaller than 180 degrees and the valve-open timing UVO of the intake valve is after the top dead center TDC, the valve-open timing IVO is advanced.

Abstract: A control apparatus calculates a exhaust gas air-fuel ratio of a plurality of cylinders, in which the operation angle of an intake valve is set to a predetermined operation angle, e.g., a maximum operation angle, based on a value output from an air-fuel ratio sensor so as to minimize a variation in an fuel injection quantity between the plurality of cylinders by that exhaust gas air-fuel ratio. That is, the exhaust gas air-fuel ratio of the plurality of cylinders, in which the valve opening characteristics of the intake valve and an exhaust valve are set such that the intake air amount to be introduced into the plurality of cylinders is limited by the opening amount of a throttle valve, for example, and not limited by the valve opening characteristics of the intake valve or the exhaust valve is calculated, and the variation in the fuel injection quantity among the plurality of cylinders is then reduced by that exhaust gas air-fuel ratio.