A method is provided for operating a compression-ignition engine having a combustion chamber. The method includes establishing, via an injection driver, electronic communication with a primary clock configured to generate a primary time signal. The method also includes commanding an injector to introduce into the combustion chamber injections of fuel having respective pulse widths timed using the primary time signal to generate combustion within the combustion chamber. The method additionally includes detecting a loss of the primary time signal and subsequently establishing an electronic communication between the injection driver and an auxiliary clock configured to generate an auxiliary time signal. Furthermore, the method includes commanding the injector to introduce into the combustion chamber a number of injections of fuel having respective pulse widths timed using the auxiliary time signal and thereby continuing combustion within the combustion chamber. A vehicle employing the injection driver for executing the method is also provided.

A filter malfunction determination apparatus includes a calculator that calculates, upon determination that a rapid output increase has occurred, an amount of change of a parameter value output from a sensor before and after the rapid output increase. The calculator calculates, based on the calculated amount of change, a correction value for correcting at least one of the parameter value output from the sensor and a malfunction determination threshold. The filter malfunction determination apparatus includes an offset corrector configured to perform, based on the correction value, offset correction of at least one of the parameter value output from the sensor and the malfunction determination threshold after determination that the rapid output increase has occurred.

An ECU loads detected values of a rotation angle sensor and a pressure sensor which are mounted to an electric throttle, and executes an abnormal-sensor determination control to determine whether one of the rotation angle sensor and the pressure sensor is abnormal. Specifically, the ECU determines that one of the rotation angle sensor and the pressure sensor is abnormal, in a case where a state that a tendency of the actual opening angle detected by the rotation angle sensor does not match a tendency of the pressure detected by the downstream pressure sensor has continued for a period greater than or equal to a predetermined period. Therefore, since the pressure sensor can replace the rotation angle sensor used for detecting abnormality in a conventional technology, two rotation angle sensors can be reduced to one rotation angle sensor, and a cost is reduced.

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.

A method for diagnosing a component in a gas-routing system of a supercharged combustion engine having an electrically operable compressor, the method including activating the electrically operable compressor after the combustion engine has been shut off, opening a flow path through the gas-routing system, measuring a state variable in the gas-routing system, and detecting a fault of the component as a function of the measured state variable.

An abnormality flag is set when a first abnormality determination condition is established in an abnormality diagnosis of a fuel pressure sensor and it is determined that an abnormality occurs. In a case where the abnormality flag is kept cleared, when a fuel pressure detection value of the fuel pressure sensor is kept fixed for a prescribed time T2 or more and a second abnormality determination condition is established, a partial lift injection is prohibited, such that an injection control of a fuel injection valve is performed so as to perform a fuel injection without performing the partial lift injection.

A process of causing an engine (10) to perform high-temperature exhaust driving (D1) after urea water from an urea water injection valve (33) is not supplied to an SCR catalyst (34), and a process of causing the engine (10) to perform high-flow-rate exhaust driving (D2) after a flow rate of exhaust gas from a cylinder interior (13) is not reduced are performed on an ECU (40). A process of determining deterioration or malfunction of upstream and downstream NOx sensors (47 and 48) based on detected values (Ca and Cb) acquired when the engine speed (Na) reaches a determination speed (Nx) is performed on a vehicle external computer (52).

An object is to estimate the responsiveness of an exhaust gas sensor with as high accuracy as possible and to determine abnormality in the responsiveness of the exhaust gas sensor accurately. A diagnosis apparatus for the exhaust gas sensor comprises a controller configured to perform oxygen concentration control to change the oxygen concentration in the exhaust gas, calculate a responsiveness index correlating with the responsiveness of the exhaust gas sensor by diving the largest value of an absolute change rate defined as the absolute value of the change rate of the output signal of the exhaust gas sensor during a reference period by the difference between the value of the output signal at the time when the absolute change rate becomes largest and the converged value of the output signal with the reference period, and estimate the responsiveness of said exhaust gas sensor on the basis of said responsiveness index.

A heat-ray type of airflow meter has a signal processor for converting a detected intake air quantity into a frequency signal. An engine controller has a conversion table for converting the frequency signal into an air quantity. The signal processor and the conversion table have features such that the frequency increases as the magnitude of a positive air quantity increases, and the frequency decreases as an absolute value of a negative air quantity increases. In the conversion table, a prescribed positive air quantity value is assigned a dummy output for frequencies lower than a prescribed threshold value. Under normal circumstances, frequencies lower than a minimum value are not used. The frequency decreases to near 0 Hz when there is a disconnection or a short circuit, the dummy output is therefore output, and an injection quantity equal to or greater than a misfire limit is ensured.

Methods and systems are provided for determining barometric pressure. In one example, an onboard vacuum pump is utilized to draw a vacuum at a constant flow rate across a reference orifice, and the resulting vacuum level is converted to a barometric pressure. In this way, other sensors for determining barometric pressure in a vehicle may be rationalized without the use of engine operation, and in an example where the other sensors for determining barometric pressure are not functioning as desired, barometric pressure as inferred from the onboard pump may be utilized to adjust engine operation.