An abnormality diagnosing apparatus configured to diagnose abnormality of a fuel injection amount of a diesel engine includes: an oxidation catalyst provided in an exhaust gas passage; an exhaust gas temperature detector configured to detect an upstream-side exhaust gas temperature and a downstream-side exhaust gas temperature, the upstream-side exhaust gas temperature being an exhaust gas temperature on an upstream side of the oxidation catalyst, the downstream-side exhaust gas temperature being an exhaust gas temperature on a downstream side of the oxidation catalyst; and an abnormality determining unit configured to determine whether the fuel injection amount is excessive or not on the basis of comparison between the upstream-side exhaust gas temperature and the downstream-side exhaust gas temperature.

A control device for a compression-ignited internal combustion engine includes a nozzle that includes plural injection holes arranged at intervals in the circumferential direction and that directly injects fuel to a combustion chamber, a piston that includes a cavity with an inner circumferential side surface to which a distance from the nozzle varies in the circumferential direction, a first injection hole for injecting fuel to a portion of the inner circumferential side surface to which the distance from the nozzle is the largest out of the plural injection holes, a second injection hole for injecting fuel to a portion of the inner circumferential side surface to which the distance from the nozzle is the smallest out of the plural injection holes, a detection unit that detects a heat release rate in the combustion chamber, and a control unit that determines which of the first and second injection holes is abnormal.

A diagnostic system for an engine includes: a plurality of cylinders, in-cylinder injectors, port injectors and an electronic control unit. The electronic control unit configured to make an abnormality diagnosis of an air-fuel ratio due to the in-cylinder injectors and then to make an abnormality diagnosis of the air-fuel ratio due to the port injectors. The electronic control unit is configured to make an abnormality diagnosis of the air-fuel ratio due to the in-cylinder injectors in an operating situation in which fuel is injected from only the in-cylinder injectors, and to make an abnormality diagnosis of the air-fuel ratio due to the port injectors by increasing a ratio of an injection amount of the port injectors when the electronic control unit has diagnosed that there is an abnormality of the air-fuel ratio in an operating situation in which fuel is injected from both the in-cylinder injectors and the port injectors.

A valve control device controls a valve drive mechanism on the basis of a degree-of-opening signal for a valve and a startup signal for an engine, and includes: a drive signal generating unit that, when it is determined on the basis of the startup signal that the engine is stated, generates a test drive signal for test-driving the valve before the generation of a normal drive signal associated with normal driving of the valve; and an abnormality determining unit that, on the basis of the degree-of-opening signal during the test driving, determines whether or not an abnormality has occurred in the drive mechanism. The drive signal generating unit stops generating the test drive signal and the normal drive signal when the abnormality determining unit determines that the abnormality has occurred in the drive mechanism.

Methods are provided for identifying degradation in components of a compressor recirculation valve (CRV). One method includes differentiating between degradation of a throttle of the CRV and a position sensor of the CRV based on each of a throttle inlet pressure and commanded position of the throttle of the CRV. The method also includes utilizing output from the position sensor of the CRV in response to the commanded position of the throttle of the CRV.

Current sensors measure current flowing into and out of an inductive load such as a solenoid coil and provide signals to a processor when the difference between the two measured currents exceeds a threshold. A solenoid coil and electronic devices driving it are protected from damage caused by a short circuit at the connections to the coil.

The present invention relates to a method for diagnosing a failure of a power stage of an electronic waste gate actuator (EWGA). According to the present invention, whether the failure of the power stage of the EWGA occurs is determined by confirming, by an engine control unit (ECU), information on the failure of the power stage transferred from an EWGA driver IC at the time of EWGA position learning, after an engine is turned off. By doing so, even when a turbo-charger is not used for a long time, whether the failure of the power stage of the EWGA occurs may be diagnosed for every driving cycle, such that a failure of the ECU may be prevented in advance and unnecessary replacement of components may be prevented, thereby decreasing maintenance costs for a vehicle.

An EGR valve includes a valve seat in a flow passage of a housing, a valve element seatable on the valve seat, a rotary shaft to open or close the valve element, a motor and a speed reducing mechanism, a return spring urging the valve element in a valve closing direction, and an opening-degree sensor to detect an opening degree of the valve element. An electronic control unit (ECU) diagnoses abnormality due to lodging of foreign matter between the valve seat and the valve element during full close. When driving the motor to urge the valve element in the valve closing direction during full close of the valve element, the ECU determines the EGR valve to be abnormal because of lodging of foreign matter if a difference between a value detected by the opening-degree sensor and a predetermined reference value is larger than a first determination value.

In the method provided herein, quantities of fuel are determined during a direct injection of a motor vehicle. In this connection, within one work cycle, test injections are carried out in two cylinders of an internal combustion engine of the motor vehicle during overrun phases, speed oscillations of moved masses of the cylinders are measured and a relative difference in quantity of the fuel quantity of the test injections within one work cycle is determined from the speed oscillations. By evaluating a relative signal between the test injections within one work cycle in the two cylinders, an intrinsic dependence of the drive train of the quantity of fuel signal is compensated.

Methods and systems for simultaneously operating port fuel injectors and direct fuel injectors of an internal combustion engine are described. In one example, operation of a port fuel injector is deactivated in response to an indication of reduced performance of a direct fuel injector so that degradation of the direct fuel injector may be reduced.