Abstract: A controller for controlling a valve timing of an engine that calculates a duty correction value using an arithmetic expression reflecting a physical model, which is associated with torque applied to an exhaust valve camshaft, a spring force exerted by an advancing spring for varying a rotational phase of the exhaust valve camshaft, and hydraulic pressure of operating oil. When the coolant temperature is lower than 80° C., the controller sets the duty correction value to zero. The duty correction value reflecting all the fluctuation factors of the engine is easily obtained without using a map requiring a large amount of data.

Abstract: A controller restricts an operation amount of the variable valve actuation mechanism of a fluid pressure operated type such that increase in the valve overlap amount of an engine is restrained when the engine is in a transient operation state in which the output of the engine increases. When the controller determines that the variable valve actuation mechanism is in the locked state, the controller relaxes the restriction imposed on the operation amount of the variable valve actuation mechanism. Hence, a decrease in follow-up performance of valve properties to desired properties is restrained while restraining temporary stagnation of increase in engine rotational speed caused by vehicle acceleration.

Abstract: A controller for controlling a valve timing of an engine that calculates a duty correction value using an arithmetic expression reflecting a physical model, which is associated with torque applied to an exhaust valve camshaft, a spring force exerted by an advancing spring for varying a rotational phase of the exhaust valve camshaft, and hydraulic pressure of operating oil. When the coolant temperature is lower than 80° C, the controller sets the duty correction value to zero. The duty correction value reflecting all the fluctuation factors of the engine is easily obtained without using a map requiring a large amount of data.

Abstract: A controller restricts an operation amount of the variable valve actuation mechanism of a fluid pressure operated type such that increase in the valve overlap amount of an engine is restrained when the engine is in a transient operation state in which the output of the engine increases. When the controller determines that the variable valve actuation mechanism is in the locked state, the controller relaxes the restriction imposed on the operation amount of the variable valve actuation mechanism. Hence, a decrease in follow-up performance of valve properties to desired properties is restrained while restraining temporary stagnation of increase in engine rotational speed caused by vehicle acceleration.

Abstract: An upper limit guard is set for a valve overlap amount according to a KCS learning value used to retard-correct an ignition timing in order to suppress knock, and an engine load. As a result, it is possible to make the upper limit guard value a value able to restrict the valve overlap amount to a value equal to, or less than, a value at which an internal EGR amount does not become excessive during a retard-correction of the ignition timing. By applying the upper limit guard to the valve overlap amount using the upper limit guard value, it is possible to suppress the valve overlap amount from increasing from the optimum value following a retard-correction of the ignition timing, as well as suppress the value of overlap amount from being reduced when it is not deviating from the optimum value and is below the upper limit guard value.

Abstract: In a fuel injection valve body for a direct injection type internal combustion engine, an entire nozzle body tip portion is formed in a conical shape protruding from a nozzle body outer peripheral surface covered with a cap. Therefore, neither a corner portion or a recessed portion is formed on a surface of the nozzle body tip portion. This prevents heat generated by combustion from concentrating at a corner portion or a surface area from enlarging by a recessed portion, which in turn prevents heat generated by combustion from increasing the temperature of the nozzle body tip portion. Moreover, since a foremost portion of a spherical shape is formed such that it does not form a corner portion or a recessed portion in a peripheral portion of a conical shape, heat generated by combustion does not increase the temperature of the nozzle body tip portion. The temperature of a nozzle hole can therefore be prevented from increasing and accumulation of deposits can be restricted.

Abstract: An upper limit guard is set for a valve overlap amount according to a KCS learning value used to retard-correct an ignition timing in order to suppress knock, and an engine load. As a result, it is possible to make the upper limit guard value a value able to restrict the valve overlap amount to a value equal to, or less than, a value at which an internal EGR amount does not become exvessive during a retard-correction of the ignition timing. By applying the upper limit guard to the valve overlap amount using the upper limit guard value, it is possible to suppress the valve overlap amount from increasing from the optimum value following a retard-correction of the ignition timing, as well as suppress the value of overlap amount from being reduced when it is not deviating from the optimum value and is below the upper limit guard value.

Abstract: A control apparatus for a cylinder injection type internal combustion engine in which the fuel injection mode of the engine is switched between a compression stroke injection and an intake stroke injection. When the engine is cold, the compression stroke injection is selected for the fuel injection mode so that injected fuel collides with the top surface of a piston and is directed toward the vicinity of a spark plug. When the fuel injection mode is switched from the compression stroke injection to the intake stroke injection, the ignition timing is delayed during the execution of the intake stroke injection from when the fuel injection mode is switched until a predetermined period elapses compared with a case when the fuel injection mode is not switched.

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 control apparatus for a cylinder injection type internal combustion engine in which the fuel injection mode of the engine is switched between a compression stroke injection and an intake stroke injection. When the engine is cold, the compression stroke injection is selected for the fuel injection mode so that injected fuel collides with the top surface of a piston and is directed toward the vicinity of a spark plug. When the fuel injection mode is switched from the compression stroke injection to the intake stroke injection, the ignition timing is delayed during the execution of the intake stroke injection from when the fuel injection mode is switched until a predetermined period elapses compared with a case when the fuel injection mode is not switched.

Abstract: In a fuel injection valve body for a direct injection type internal combustion engine, an entire nozzle body tip portion is formed in a conical shape protruding from a nozzle body outer peripheral surface covered with a cap. Therefore, neither a corner portion or a recessed portion is formed on a surface of the nozzle body tip portion. This prevents heat generated by combustion from concentrating at a corner portion or a surface area from enlarging by a recessed portion, which in turn prevents heat generated by combustion from increasing the temperature of the nozzle body tip portion. Moreover, since a foremost portion of a spherical shape is formed such that it does not form a corner portion or a recessed portion in a peripheral portion of a conical shape, heat generated by combustion does not increase the temperature of the nozzle body tip portion. The temperature of a nozzle hole can therefore be prevented from increasing and accumulation of deposits can be restricted.

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 idle speed control device according to the present invention controls a two-solenoid rotary type idle speed control valve properly even when one of the solenoids fails. When one of the solenoids fails, the device calculates the amount of bypass air from the amount of inlet air and the degree of opening of the throttle valve, and estimates the degree of opening of the idle speed control valve. If the degree of opening of the bypass valve is larger than that of the neutral valve position, the device sets the duty ratio of the control signal for driving the idle speed control valve at 0%, and if the degree of opening of the idle speed control valve is less than that of the neutral valve position, the device sets the duty ratio of the control signal at 100%. By this control, the two-solenoid rotary type idle speed control valve is maintained at neutral valve position without determining the type of the failure of the solenoids precisely.