Abstract: An abnormality determination apparatus for an intake amount control mechanism according to the invention includes a control portion which sets an allowable range of an opening amount of a throttle valve which provided in an intake passageway of an internal combustion engine based at least on an index value of an engine operation state, including an operation amount of accelerator, and on a lift working angle of an intake valve, and which determines that an abnormality is present in a state of driving of the throttle valve if an actual opening amount of the throttle valve is outside the allowable range set.

Abstract: An engine has a variable valve actuation mechanism that varies lift characteristics of an intake valve. An idle speed control apparatus has a control section for controlling an intake air amount of the engine in an idle state for adjusting an actual engine speed to a target engine speed. The control section sets a control amount related to control of the intake air amount in correspondence with the lift characteristics, which are varied by the variable valve actuation mechanism. Accordingly, the engine speed in the idle state is effectively controlled in correspondence with changes of the lift characteristics.

Abstract: An abnormality determination apparatus for an intake amount control mechanism according to the invention includes a control portion which sets an allowable range of an opening amount of a throttle valve which provided in an intake passageway of an internal combustion engine based at least on an index value of an engine operation state, including an operation amount of accelerator, and on a lift working angle of an intake valve, and which determines that an abnormality is present in a state of driving of the throttle valve if an actual opening amount of the throttle valve is outside the allowable range set.

Abstract: An abnormality determination apparatus for an intake amount control mechanism according to the invention includes a control portion which sets an allowable range of an opening amount of a throttle valve which provided in an intake passageway of an internal combustion engine based at least on an index value of an engine operation state, including an operation amount of accelerator, and on a lift working angle of an intake valve, and which determines that an abnormality is present in a state of driving of the throttle valve if an actual opening amount of the throttle valve is outside the allowable range set.

Abstract: An engine has a variable valve actuation mechanism that varies lift characteristics of an intake valve. An idle speed control apparatus has a control section for controlling an intake air amount of the engine in an idle state for adjusting an actual engine speed to a target engine speed. The control section sets a control amount related to control of the intake air amount in correspondence with the lift characteristics, which are varied by the variable valve actuation mechanism. Accordingly, the engine speed in the idle state is effectively controlled in correspondence with changes of the lift characteristics.

Abstract: If it is determined that an engine has been started, an engine coolant temperature is detected. If the engine coolant temperature is equal to or lower than a threshold value, the catalyst quick warm-up control is started to retard ignition timing, and a signal indicating a command to increase an operate angle is transmitted to a VVLA controller. When a VVT hydraulic pressure is increased to a predetermined value, a signal indicating a command to decrease the operate angle is transmitted to the VVLA controller, and a signal indicating a command to advance open timing of an intake valve is transmitted to a VVT controller so that the open timing of the intake valve is not changed. If the engine coolant temperature is equal to or higher than a threshold value, the catalyst quick warm-up control ends, and the ignition timing is returned to normal timing.

Abstract: An electronic control unit increases the maximum lift amount or the working angle of an intake valve if it is determined that the operation for stopping an engine is performed. The electronic control unit stops fuel injection or ignition before increasing the maximum lift amount or the working angle.

Abstract: A control apparatus for an internal combustion engine provided with a fuel vapor treatment system according to the invention includes a controller that discharges fuel vapor into an intake passageway by using the intake negative pressure, and which adjusts the amount of the intake air through the cooperative control of a variable control of at least one of the lift amount of an intake valve and the working angle of the intake valve, and a control of the degree of opening of a throttle valve. In addition, the control apparatus executes the variable control so that at least one of the lift amount and the working angle of the intake valve changes in accordance with the fuel vapor concentration in the fuel vapor treatment system.

Abstract: If it is determined that an engine has been started, an engine coolant temperature is detected. If the engine coolant temperature is equal to or lower than a threshold value, the catalyst quick warm-up control is started to retard ignition timing, and a signal indicating a command to increase an operate angle is transmitted to a VVLA controller. When a VVT hydraulic pressure is increased to a predetermined value, a signal indicating a command to decrease the operate angle is transmitted to the VVLA controller, and a signal indicating a command to advance open timing of an intake valve is transmitted to a VVT controller so that the open timing of the intake valve is not changed. If the engine coolant temperature is equal to or higher than a threshold value, the catalyst quick warm-up control ends, and the ignition timing is returned to normal timing.

Abstract: An ignition timing control apparatus for an engine includes a controller that sets an ignition timing considering a change of a temperature or a pressure in a combustion chamber at a time when an opening/closing characteristic of an intake valve is changed, the opening/closing characteristic including a valve opening timing and a valve closing timing at least one of which is changed by a variable valve mechanism for the engine.

Abstract: An controller detects a change in a load generation state of an accessory device that generates a load on the internal combustion engine during operation, and the controller in turn controls a variable valve mechanism to change at least one of an operation angle and a valve lift of an intake valve of the internal combustion engine, as well as changing an amount of an intake air drawn into the internal combustion engine, in response to the detected change in the load generation state of the accessory device.

Abstract: An electronic control unit increases the maximum lift amount or the working angle of an intake valve if it is determined that the operation for stopping an engine is performed. The electronic control unit stops fuel injection or ignition before increasing the maximum lift amount or the working angle.

Abstract: An ignition timing control apparatus for an engine includes a controller that sets an ignition timing considering a change of a temperature or a pressure in a combustion chamber at a time when an opening/closing characteristic of an intake valve is changed, the opening/closing characteristic including a valve opening timing and a valve closing timing at least one of which is changed by a variable valve mechanism for the engine.

Abstract: a control apparatus for an internal combustion engine provided with a fuel vapor treatment system according to the invention includes a controller that discharges fuel vapor into an intake passageway by using the intake negative pressure, and which adjusts the amount of the intake air through the cooperative control of a variable control of at least one of the lift amount of an intake valve and the working angle of the intake valve, and a control of the degree of opening of a throttle valve. In addition, the control apparatus executes the variable control so that at least one of the lift amount and the working angle of the intake valve changes in accordance with the fuel vapor concentration in the fuel vapor treatment system.

Abstract: An abnormality determination apparatus for an intake amount control mechanism according to the invention includes a control portion which sets an allowable range of an opening amount of a throttle valve which provided in an intake passageway of an internal combustion engine based at least on an index value of an engine operation state, including an operation amount of accelerator, and on a lift working angle of an intake valve, and which determines that an abnormality is present in a state of driving of the throttle valve if an actual opening amount of the throttle valve is outside the allowable range set.

Abstract: An controller detects a change in a load generation state of an accessory device that generates a load on the internal combustion engine during operation, and the controller in turn controls a variable valve mechanism to change at least one of an operation angle and a valve lift of an intake valve of the internal combustion engine, as well as changing an amount of an intake air drawn into the internal combustion engine, in response to the detected change in the load generation state of the accessory device.

Abstract: A fuel injection mode is flexibly controlled according to the actual extent of adverse effects on an internal combustion engine from both deterioration of exhaust gas emissions and fuel dilution caused by fuel adhering to the piston top face and the cylinder inner peripheral face. A dilution degree counter value C is counted up when a coolant temperature at engine startup THWST and an intake air quantity sum value after engine startup GASUM are each equal to, or less than, respective predetermined values. A fuel dilution flag is set to “ON” when the dilution degree counter value C is equal to, or greater than, a predetermined value CH. A fuel injection timing of an intake stroke injection is changed to a timing on the advance side when this fuel dilution flag is “ON.

Abstract: An evaporative fuel processing system for an in-cylinder injection type internal combustion engine includes an evaporative fuel processing mechanism that includes a canister to which an evaporative fuel in a fuel supply system is adsorbed and performs an operation for purging the adsorbed evaporative fuel into an intake system of the internal combustion engine. The system further includes a controller that estimates a degree of dilution occurred in a lubricating oil for the internal combustion engine with a fuel mixed therewith, and inhibits the purging operation performed by the evaporative fuel processing mechanism when the estimated degree of dilution is equal to or larger than a predetermined value.

Abstract: It is highly likely that fuel is already adhered to the inside wall surface of the combustion chamber at the beginning of engine startup when it is estimated that the temperature at the beginning of engine stop of the most recent engine operation is low when the engine is restarted. Under these conditions, a fuel injection quantity is reduced or an intake air quantity is increased when the engine is restarted. Therefore, even if the adhered fuel vaporizes when the engine is restarted, the air-fuel ratio will not become excessively rich as a result.

Abstract: A control apparatus for suppressing vibrations of an engine when combustion is stopped. The control apparatus maintains an engine rotational speed at a reference rotational speed for a reference time when the combustion of the engine is automatically stopped. This results in a reduction in pressure in a combustion chamber of the engine. The control apparatus gradually reduces the rotational speed of the crankshaft, and stops the crankshaft before the rotational speed of the crankshaft reaches a resonant speed. In this way, the resonance and increased pressure in the combustion chamber are prevented to reduce vibrations of the vehicle.