Abstract: A control apparatus for an internal combustion engine includes phase change means (60) for advancing or retarding phases of an opening timing and a closing timing of an intake valve (62); duration change means (60) for increasing or decreasing a duration of the intake valve (62); and EGR gas amount increase means (50) for increasing an amount of EGR gas, based on an operating state of an internal combustion engine. The control apparatus further includes intake-valve closing timing advancing means (50) for advancing the intake-valve closing timing when the amount of EGR gas is increased. The intake-valve closing timing advancing means (50) advances the intake-valve closing timing by performing a first operation that advances the phases using the phase change means (60), and performing a second operation that decreases the duration using the duration change means (60), and makes a timing at which the second operation is started later than a timing at which the first operation is started.

Abstract: An object of the present invention is to provide a technology that enables reduction of NOx stored in an NOx catalyst with improved efficiency in an exhaust gas purification system for an internal combustion engine. According to the present invention, when NOx stored in the NOx catalyst is to be reduced, if the temperature of the NOx catalyst is lower than a specific temperature, the air-fuel ratio of the ambient atmosphere around the NOx catalyst is decreased only by decreasing the air-fuel ratio of the exhaust gas discharged from the internal combustion engine, and if the temperature of the NOx catalyst is not lower than the specific temperature, the air-fuel ratio of the ambient atmosphere around the NOx catalyst is decreased either only by adding reducing agent through reducing agent addition means, or by decreasing the air-fuel ratio of the exhaust gas discharged from the internal combustion engine and adding reducing agent through the reducing agent addition means.

Abstract: A control apparatus for an internal combustion engine (10) includes intake valve control means (50). The internal combustion engine (10) includes a variable intake valve operating mechanism (66) that changes a valve opening characteristic of an intake valve (64), and rich combustion is performed in the internal combustion engine (10) to control an exhaust gas purification catalyst (24) disposed in an exhaust passage (18). The intake valve control means (50) controls the valve opening characteristic of the intake valve (64) to increase a flow rate of intake air in an early stage of an intake stroke when the rich combustion is performed, as compared to when non-rich combustion is performed.

Abstract: An internal combustion engine control apparatus that prevents an abrupt change in the air amount at the time of supercharger switching. The control apparatus enters a small turbo operating state in which a small turbocharger is mainly operative, during relatively low-rotation-speed and low-load side, and enters a large turbo operating state in which a large turbocharger is mainly operative, in a relatively high-rotation-speed and high-load. In the small turbo operating state, the control apparatus can exercise charging efficiency enhancement control by using a scavenging effect. Before switching from the small turbo operating state to the large turbo operating state, the control apparatus predicts whether the large turbocharger will build up its boost pressure quickly or slowly. When slow boost pressure is predicted, the control apparatus exercises charging efficiency enhancement control to provide a low degree of charging efficiency enhancement.

Abstract: An internal combustion engine control apparatus that prevents an abrupt change in the air amount at the time of supercharger switching. The control apparatus enters a small turbo operating state in which a small turbocharger is mainly operative, during relatively low-rotation-speed and low-load side, and enters a large turbo operating state in which a large turbocharger is mainly operative, in a relatively high-rotation-speed and high-load. In the small turbo operating state, the control apparatus can exercise charging efficiency enhancement control by using a scavenging effect. Before switching from the small turbo operating state to the large turbo operating state, the control apparatus predicts whether the large turbocharger will build up its boost pressure quickly or slowly. When slow boost pressure is predicted, the control apparatus exercises charging efficiency enhancement control to provide a low degree of charging efficiency enhancement.

Abstract: An object of the present invention is to provide a technology that enables reduction of NOx stored in an NOx catalyst with improved efficiency in an exhaust gas purification system for an internal combustion engine. According to the present invention, when NOx stored in the NOx catalyst is to be reduced, if the temperature of the NOx catalyst is lower than a specific temperature, the air-fuel ratio of the ambient atmosphere around the NOx catalyst is decreased only by decreasing the air-fuel ratio of the exhaust gas discharged from the internal combustion engine, and if the temperature of the NOx catalyst is not lower than the specific temperature, the air-fuel ratio of the ambient atmosphere around the NOx catalyst is decreased either only by adding reducing agent through reducing agent addition means, or by decreasing the air-fuel ratio of the exhaust gas discharged from the internal combustion engine and adding reducing agent through the reducing agent addition means.

Abstract: A control apparatus for an internal combustion engine includes phase change means (60) for advancing or retarding phases of an opening timing and a closing timing of an intake valve (62); duration change means (60) for increasing or decreasing a duration of the intake valve (62); and EGR gas amount increase means (50) for increasing an amount of EGR gas, based on an operating state of an internal combustion engine. The control apparatus further includes intake-valve closing timing advancing means (50) for advancing the intake-valve closing timing when the amount of EGR gas is increased. The intake-valve closing timing advancing means (50) advances the intake-valve closing timing by performing a first operation that advances the phases using the phase change means (60), and performing a second operation that decreases the duration using the duration change means (60), and makes a timing at which the second operation is started later than a timing at which the first operation is started.

Abstract: A control apparatus for an internal combustion engine (10) includes intake valve control means (50). The internal combustion engine (10) includes a variable intake valve operating mechanism (66) that changes a valve opening characteristic of an intake valve (64), and rich combustion is performed in the internal combustion engine (10) to control an exhaust gas purification catalyst (24) disposed in an exhaust passage (18). The intake valve control means (50) controls the valve opening characteristic of the intake valve (64) to increase a flow rate of intake air in an early stage of an intake stroke when the rich combustion is performed, as compared to when non-rich combustion is performed.

Abstract: The present invention relates to a control apparatus for an internal combustion engine. An object of the present invention is to suppress deterioration of emission and fuel consumption arising during acceleration due to an effect of an exhaust valve opening timing. An upper limit of a fuel injection quantity is set based on the exhaust valve opening timing. The fuel injection quantity is limited to the upper limit or less when the fuel injection quantity is increased during acceleration. The exhaust valve opening timing at which the upper limit is maximized is set to a relatively advanced timing in a low engine speed range, moving in the retard direction as the engine speed rises from the low engine speed range toward a mid engine speed range, and moving in the advance direction as the engine speed rises further from the mid engine speed range toward a high engine speed range.