Abstract: A first parameter correlated with a degree of fluctuation of output from an air-fuel ratio sensor is calculated, and whether or not the calculated first parameter has a value between a predetermined primary determination upper-limit value ?1H and a primary determination lower-limit value is determined. Such forced active control as reduces an air-fuel ratio shift in one of the cylinders which is subjected to a most significant air-fuel ratio shift is performed when the calculated first parameter is determined to have a value between the predetermined primary determination upper-limit value and the primary determination lower-limit value. A first parameter is calculated while the forced active control is in execution. The calculated first parameter is compared with a predetermined secondary determination value to determine whether or not variation abnormality is present.

Abstract: A first parameter correlated with a degree of fluctuation of output from an air-fuel ratio sensor is calculated, and whether or not the calculated first parameter has a value between a predetermined primary determination upper-limit value ?1H and a primary determination lower-limit value is determined. Such forced active control as reduces an air-fuel ratio shift in one of the cylinders which is subjected to a most significant air-fuel ratio shift is performed when the calculated first parameter is determined to have a value between the predetermined primary determination upper-limit value and the primary determination lower-limit value. A first parameter is calculated while the forced active control is in execution. The calculated first parameter is compared with a predetermined secondary determination value to determine whether or not variation abnormality is present.

Abstract: A combustion control apparatus for an internal combustion engine that switches combustion modes at the proper timing. At the time of switching from a stratified-charge combustion mode to a homogeneous-charge combustion mode, the angle of an EGR valve is changed to the angle needed for the homogeneous-charge combustion mode first. When a predetermined delay time elapses after a request for switching the combustion mode has been made, substantial mode switching is carried out. The delay time is set based on engine speed and engine load.

Abstract: A direct-fuel-injection-type internal combustion engine is equipped with an injector for injecting fuel directly into a combustion chamber of a cylinder. A controller controls the degree of opening of a throttle valve for adjusting the amount of air drawn into the combustion chamber and sets the throttle valve to a closed valve state by setting the degree of opening of the throttle valve to a degree of opening that is on the closed valve side of a post-engine start target degree of opening, when the engine is to be started. After it is determined that a start of the engine has been accomplished, the controller opens the throttle valve by gradually increasing the degree of opening of the throttle valve from the degree of opening of the closed valve state to the post-engine start target degree of opening.

Abstract: A fuel vapor treating mechanism includes a canister for adsorbing fuel vapor produced in a fuel feed system. The treating mechanism purges the fuel vapor adsorbed by the canister, along with air, to an intake system of the engine. An ECU computes a value representing the flow rate of the purged gas as a value that represents the capability of the treating apparatus. The ECU sets a decision value in accordance with the amount of the fuel vapor produced in the fuel feed system. The decision value represents a required capability of the treating mechanism. When the value representing the capability is less than the decision value, the ECU prohibits stratified charge combustion and causes the engine to perform homogeneous charge combustion. Therefore, as many opportunities as possible are provided to perform stratified charge combustion, which improves fuel efficiency.

Abstract: The technique of the present invention reduces or even omits potential shocks and vibrations arising due to the coupling action of a coupling mechanism at the time of starting an internal combustion engine, and ensures a quick restart of the internal combustion engine. In a vehicle with an idling stop control apparatus of the present invention mounted thereon, a control unit inputs an inverted phase current Eon, which is determined according to the energy absorbing state of a transmission belt, into an auxiliary machinery driving electric motor, so as to brake rotations of the auxiliary machinery driving electric motor. After the input of the inverted phase current Eon into the auxiliary machinery driving electric motor, the control unit couples an electromagnetic clutch to link a crankshaft of the internal combustion engine with the auxiliary machinery driving electric motor. The value of the inverted phase current Eon is varied according to the energy absorbing state of the transmission belt.

Abstract: A combustion control apparatus for an internal combustion engine that switches combustion modes at the proper timing. At the time of switching from a stratified-charge combustion mode to a homogeneous-charge combustion mode, the angle of an EGR valve is changed to the angle needed for the homogeneous-charge combustion mode first. When a predetermined delay time elapses after a request for switching the combustion mode has been made, substantial mode switching is carried out. The delay time is set based on engine speed and engine load.

Abstract: A fuel injection controller of a cylinder injection engine selects an injection mode from various fuel injection modes including an intake stroke injection mode, in which fuel is injected during an intake stroke, and a compression stroke injection mode, in which fuel is injected during a compression stroke. The controller includes a selector for selecting the compression stroke injection mode when the engine is cool if the temperature of the engine when the engine is started is within a predetermined temperature range and for selecting the intake stroke injection mode when the engine is cool if the temperature of the engine when the engine is started is higher than the predetermined temperature range.

Abstract: An engine performs a combustion mode selected from a plurality of combustion modes. The combustion modes include stratified-charge combustion and homogeneous-charge combustion. A electronic control unit switches the combustion mode in accordance with the current running conditions of the engine. The electronic control unit limits a running area in which stratified-charge combustion is performed in accordance with the frequency of engine knocking occurrences. This properly executes knocking control without adversely affecting the execution of is stratified-charge combustion.

Abstract: An engine includes a variable valve timing mechanism to adjust the valve overlap of intake valves and exhaust valves in accordance with the running state of the engine. The engine operates either in stratified charge combustion mode or in homogenous charge combustion mode in accordance with the running state of the engine. When, for example, the VVT cannot operate normally due to lack of hydraulic pressure, an ECU judges that the state of the VVT is not suitable for stratified combustion and forces the engine to operate in the homogenous combustion mode regardless of the running state of the engine. As a result, the combustion state of the engine does not deteriorated and the amount of NOx in the exhaust gas does not increase.

Abstract: A direct-fuel-injection-type internal combustion engine is equipped with an injector for injecting fuel directly into a combustion chamber of a cylinder. A controller controls the degree of opening of a throttle valve for adjusting the amount of air drawn into the combustion chamber and sets the throttle valve to a closed valve state by setting the degree of opening of the throttle valve to a degree of opening that is on the closed valve side of a post-engine start target degree of opening, when the engine is to be started. After it is determined that a start of the engine has been accomplished, the controller opens the throttle valve by gradually increasing the degree of opening of the throttle valve from the degree of opening of the closed valve state to the post-engine start target degree of opening.

Abstract: The technique of the present invention reduces or even omits potential shocks and vibrations arising due to the coupling action of a coupling mechanism at the time of starting an internal combustion engine, and ensures a quick restart of the internal combustion engine. In a vehicle with an idling stop control apparatus of the present invention mounted thereon, a control unit inputs an inverted phase current Eon, which is determined according to the energy absorbing state of a transmission belt, into an auxiliary machinery driving electric motor, so as to brake rotations of the auxiliary machinery driving electric motor. After the input of the inverted phase current Eon into the auxiliary machinery driving electric motor, the control unit couples an electromagnetic clutch to link a crankshaft of the internal combustion engine with the auxiliary machinery driving electric motor. The value of the inverted phase current Eon is varied according to the energy absorbing state of the transmission belt.

Abstract: An improved apparatus is provided to control supply of airflow to an engine. The engine includes a combustion chamber connected to an air intake passage and an air exhaust passage. An air intake valve selectively opens and closes the intake passage to control the supply of the airflow to the combustion chamber. An air exhaust valve selectively opens and closes the exhaust passage to control the discharge of the exhaust gas from the combustion chamber. An altering device alters a period of an overlap of the valves by changing a valve timing of valves. A first detector detects a driving state of the engine. An ECU computes a target valve timing based on the detected driving state of the engine controls the altering device based on the computed target valve timing. An adjusting device is arranged in the intake passage to adjust the supply of the airflow to the combustion chamber. The ECU computes a target amount of the airflow to be supplied to the engine in an idling state.

Abstract: A valve timing control device includes a hydraulic variable valve timing mechanism (VVT). The VVT alters valve timing of the intake valve and/or the exhaust valve. An electronic control unit (ECU) controls the VVT for obtaining overlap suitable for the running condition of the engine, that is, the VVT allows the actual phase angle of the valve timing to approach the target phase angle suitable for the running condition of the engine. A malfunction detection apparatus including the ECU detects a malfunction of the valve timing control device. The ECU judges whether the engine is stalled. The ECU determines whether the actual phase angle of the valve timing corresponds to a specific state, which suggests a malfunction of the valve timing control device. When detecting the stalling of the engine, the ECU detects whether it has judged that the actual phase angle of the valve timing corresponds to the specific state.

Abstract: In detecting the occurrence of an abnormality in a variable valve timing mechanism, which continuously changes a valve timing by advancing or delaying the displacement angle of an intake-side cam shaft with respect to a crankshaft, an abnormality detecting apparatus for a valve timing control apparatus determines that the variable valve timing mechanism is failing when the absolute value of the difference between a target displacement angle and a correct real displacement angle, obtained by subtracting the maximum delay-angle learning value from the real displacement angle, is greater than a first predetermined value and the absolute value of the difference between a correct real displacement angle and a previous correct real displacement angle is equal to or smaller than a second predetermined value.

Abstract: A fuel injection amount control apparatus for an engine comprises injectors for injecting fuel to an engine and an electronic control unit (ECU) for controlling the injectors. The ECU learns the deviation between the air-fuel ratio of a flammable mixture to be supplied to the engine and the target value. The ECU controls the amount of fuel injection to the engine by reflecting the learning value on the computation of the injection amount. The engine has intake valves, exhaust valves and an apparatus for altering the open/close characteristics of the intake valves. The ECU computes the learning value of the air-fuel ratio in accordance with the behavior of the characteristic altering apparatus and the running conditions of the engine. When the coolant temperature of the engine is low and the learning value is not renewed, the ECU compensates the already updated learning value to a smaller value.

Abstract: A valve timing control apparatus that continuously controls the valve timing of an intake valve or an exhaust valve of an engine. This apparatus includes a hydraulic variable valve timing mechanism, a hydraulic control valve and an electronic control unit for controlling the control valve. The variable valve timing mechanism alters the valve timing to change the valve overlap of the intake valve with respect to the exhaust valve. The hydraulic control valve controls the hydraulic pressure supplied to the variable valve timing mechanism. The real phase of the valve timing is coincided with a target phase that corresponds with the running conditions of the engine. When the real phase of the valve timing approaches the target phase, the hydraulic control valve is controlled to sustain the phase of that instant. The electronic control unit, which learns the control state of the valve-timing sustaining control, sets an initial learning value that reduces the valve overlap when the learning has started.

Abstract: A valve timing control apparatus that continuously controls the valve timing of an intake valve or an exhaust valve of an engine. This apparatus includes a hydraulic variable valve timing mechanism, a hydraulic control valve and an electronic control unit for controlling the control valve. The variable valve timing mechanism alters the valve timing to change the valve overlap of the intake valve with respect to the exhaust valve. The hydraulic control valve controls the hydraulic pressure supplied to the variable valve timing mechanism. The real phase of the valve timing is coincided with a target phase that corresponds with the running conditions of the engine. When the real phase of the valve timing approaches the target phase, the hydraulic control valve is controlled to sustain the phase of that instant. The electronic control unit, which learns the control state of the valve-timing sustaining control, sets an initial learning value that reduces the valve overlap when the learning has started.

Abstract: A valve timing control apparatus that continuously controls the valve timing of an intake valve or an exhaust valve of an engine. This apparatus includes a hydraulic variable valve timing mechanism, a hydraulic control valve and an electronic control unit for controlling the control valve. The variable valve timing mechanism alters the valve timing to change the valve overlap of the intake valve with respect to the exhaust valve. The hydraulic control valve controls the hydraulic pressure supplied to the variable valve timing mechanism. The real phase of the valve timing is coincided with a target phase that corresponds with the running conditions of the engine. When the real phase of the valve timing approaches the target phase, the hydraulic control valve is controlled to sustain the phase of that instant. The electronic control unit, which learns the control state of the valve-timing sustaining control, sets an initial learning value that reduces the valve overlap when the learning has started.

Abstract: An improvement of a valve timing control apparatus for an engine is disclosed. The apparatus has an intake valve and an exhaust valve which are alternately opened and closed in a valve timing sequence according to a rotation of a cam shaft. A timing pulley mounted on the cam shaft has a housing accommodating a plunger movable therein and a sleeve secured to the cam shaft. The housing has a first and second pressure chambers defined by the plunger and sealed with respect to each other. The plunger is arranged to move in an axial direction to selectively advance and retard the cam shaft based on differential pressure between the first pressure chamber and the second pressure chamber. A controller controls an electromagnetic valve with a specific control value to adjust the fluid pressure to be supplied to the first and second pressure chambers to maintain the valve timing sequence converged to a target valve timing.