Abstract: When an engine is driven in a high engine-load condition, a split fuel injection is performed in which a required fuel injection quantity is injected by multiple fuel injections. While the split fuel injection is performed, an actual air-fuel ratio of each cylinder is individually computed based on the output of the air-fuel ratio sensor. Based on the actual air-fuel ratio and a reference air-fuel ratio, an injection-quantity variation of each cylinder is computed. A correction value is computed and learned in order to correct the injection-quantity variation of each cylinder.

Abstract: A pressure reducing valve is provided for reducing fuel pressure in a high-pressure fuel system, which supplies high-pressure fuel from a high-pressure pump to an injector, after an engine stops. An ECU detects or estimates an engine stop position when the engine stops and sets after-stop target fuel pressure in accordance with the detected or estimated engine stop position. The ECU controls a valve opening action of the pressure reducing valve to reduce the fuel pressure in the high-pressure fuel system to the after-stop target fuel pressure after the engine stops. In the control, the ECU sets the after-stop target fuel pressure to be lower as a piston position of a cylinder in a compression stroke at the engine stop position is closer to a top dead center.

Abstract: An opening of a waste gate vale is adjusted to control an actual supercharging pressure of intake air. Abnormality in a changing characteristic of the actual supercharging pressure relative to a change in a TCV control duty value can be detected. When an engine is in a steady operation condition, the TCV control duty value is forcibly changed repeatedly by a predetermined amount from 0% to 100%. A deviation between a target supercharging pressure corresponding to the TCV control duty value and an actual supercharging pressure is calculated each time the TCV control duty value is changed by the predetermined amount. This deviation is compared with an abnormality determination value to determine presence/absence of the abnormality in the changing characteristic of the actual supercharging pressure relative to the change in the TCV control duty value.

Abstract: An exhaust gas discharged from a combustion chamber of each cylinder flows near an air-fuel ratio sensor via a junction. An ECU estimates an air-fuel ratio of each cylinder based upon a sensing value of an air-fuel ratio sensor. When a variation in the air-fuel ratio among the cylinders is equal to or greater than a predetermined value, the ECU determines that an abnormality exists in the air-fuel ratio. When a quantity of the exhaust gas discharged from each cylinder is less than another predetermined value, an intake air quantity is increased and ignition timing is delayed before the determination of presence or absence of the abnormality.

Abstract: A pressure reducing valve is provided for reducing fuel pressure in a high-pressure fuel system, which supplies high-pressure fuel from a high-pressure pump to an injector, after an engine stops. An ECU detects or estimates an engine stop position when the engine stops and sets after-stop target fuel pressure in accordance with the detected or estimated engine stop position. The ECU controls a valve opening action of the pressure reducing valve to reduce the fuel pressure in the high-pressure fuel system to the after-stop target fuel pressure after the engine stops. In the control, the ECU sets the after-stop target fuel pressure to be lower as a piston position of a cylinder in a compression stroke at the engine stop position is closer to a top dead center.

Abstract: An exhaust gas discharged from a combustion chamber of each cylinder flows near an air-fuel ratio sensor via a junction. An ECU estimates an air-fuel ratio of each cylinder based upon a sensing value of an air-fuel ratio sensor. When a variation in the air-fuel ratio among the cylinders is equal to or greater than a predetermined value, the ECU determines that an abnormality exists in the air-fuel ratio. When a quantity of the exhaust gas discharged from each cylinder is less than another predetermined value, an intake air quantity is increased and ignition timing is delayed before the determination of presence or absence of the abnormality.

Abstract: A malfunction detection apparatus is disclosed for a forced induction system. The system includes a compressor provided on an upstream side of a throttle valve in an intake passage of an engine, an upstream intake pressure sensor that detects intake pressure between the compressor and the throttle valve, and an atmospheric pressure sensor that detects atmospheric pressure. The malfunction detection apparatus includes a malfunction detection program that makes a comparison between the atmospheric pressure detected by the atmospheric pressure sensor and the upstream intake pressure detected by the upstream intake pressure sensor. The comparison is made in an operating state of the forced induction system in which the compressor compresses an amount of air that is approximately equal to or less than a predetermined amount to thereby determine whether the upstream pressure sensor has a malfunction.

Abstract: A malfunction detection apparatus is disclosed for a forced induction system. The system includes a compressor provided on an upstream side of a throttle valve in an intake passage of an engine, an upstream intake pressure sensor that detects intake pressure between the compressor and the throttle valve, and an atmospheric pressure sensor that detects atmospheric pressure. The malfunction detection apparatus includes a malfunction detection program that makes a comparison between the atmospheric pressure detected by the atmospheric pressure sensor and the upstream intake pressure detected by the upstream intake pressure sensor. The comparison is made in an operating state of the forced induction system in which the compressor compresses an amount of air that is approximately equal to or less than a predetermined amount to thereby determine whether the upstream pressure sensor has a malfunction.

Abstract: An opening of a waste gate vale is adjusted to control an actual supercharging pressure of intake air. Abnormality in a changing characteristic of the actual supercharging pressure relative to a change in a TCV control duty value can be detected. When an engine is in a steady operation condition, the TCV control duty value is forcibly changed repeatedly by a predetermined amount from 0% to 100%. A deviation between a target supercharging pressure corresponding to the TCV control duty value and an actual supercharging pressure is calculated each time the TCV control duty value is changed by the predetermined amount. This deviation is compared with an abnormality determination value to determine presence/absence of the abnormality in the changing characteristic of the actual supercharging pressure relative to the change in the TCV control duty value.

Abstract: In a vibration sensing device for sensing a knocking vibration of an engine, a piezoelectric element is connected to an output terminal through a resilient conductive member. The resilient conductive member has a fixed base part, a sliding part at a position opposite to the fixed base part, and an intermediate V-shaped part resiliently contacting the piezoelectric element. When the sliding part moves slidingly in response to vibration of the piezoelectric element, the sliding friction force which exerts on the sliding part increases the spring constant of the resilient conductive member to be larger than the stationary spring constant of the same by hysteresis characteristics, thereby reducing damage to the piezoelectric element and enhancing reliability of the electric connection.