A method for detecting a leaking point in a heat recovery system of an internal combustion engine of a motor vehicle, wherein the heat recovery system includes a combustible working medium and a working medium circuit with an evaporator, a pump and an expansion machine. The recirculated exhaust gas of the engine flows through or around the evaporator which is arranged in an exhaust-gas return line. At least one oxidation catalytic converter is arranged in an exhaust gas line of the engine. A first temperature sensor is arranged in the exhaust gas line upstream and a second exhaust gas temperature sensor is arranged downstream of the oxidation catalytic converter. Temperatures of the exhaust gas are measured with these temperature sensors during operation of the engine in the exhaust gas line upstream and downstream of the oxidation catalytic converter. A temperature difference of the exhaust gas upstream and downstream of the oxidation catalyst is determined, wherein upon occurrence of an abnormally high temperature difference a conclusion is drawn on a leak in the evaporator.

A combustion system (100), a control module (104) for a combustion system (100) and a method of operating the combustion system (100) are disclosed. The method may be implemented by the control module (104) in the combustion system (100). The method comprises predicting an iced condition of the pressure sensor assembly (240); responsive to predicting the iced condition, controlling exhaust emissions without using a pressure parameter sensed with the pressure sensor assembly (240) in the iced condition; predicting a de-iced condition of the pressure sensor assembly (240); and responsive to predicting the de-iced condition, controlling the exhaust emissions using the pressure parameter sensed with the pressure sensor assembly (240) in the de-iced condition.

Downstream side air-fuel ratio sensor signal based adaptive air-fuel ratio control. When the air-fuel ratio detected by the downstream side air-fuel ratio sensor is maintained lean unduly, a stuck learning control is performed to decrease a learning value to lower the air-fuel ratio. Adaptive learning value update control is performed based on the downstream side air-fuel ratio sensor signal to increase the learning value when an upstream air-fuel ratio deviates to the rich side and to decrease the learning value when the upstream air-fuel ratio deviates to the lean side. It is judged that the downstream side air-fuel ratio sensor is abnormal when a certain value or more of decrease of the learning value and a certain value or more of increase of the learning value are repeated.

Methods and systems are provided for diagnosing a fault condition of an exhaust gas oxygen sensor downstream of a catalyst in an exhaust system of a vehicle. In one example, a method may include determining a ratio of a rate of change of a fractional oxidation state of the catalyst to a rate of change of an output voltage of the oxygen sensor. If the ratio is positive, a fault is diagnosed and subsequent adjustment of engine operation does not take into account feedback from the oxygen sensor.

Methods and systems are provided for diagnosing a fault condition of an exhaust gas oxygen sensor downstream of a catalyst in an exhaust system of a vehicle. In one example, a method may include determining a ratio of a rate of change of a fractional oxidation state of the catalyst to a rate of change of an output voltage of the oxygen sensor. If the ratio is positive, a fault is diagnosed and subsequent adjustment of engine operation does not take into account feedback from the oxygen sensor.

A gas sensor includes a sensor element made of an oxygen-ion conductive solid electrolyte, at least one electrode provided to the sensor element so as to contact a measurement gas, and a controller configured to control the gas sensor. The sensor element is heated, by a heater provided to the sensor element, at a temperature higher than an operating temperature set in advance for a predetermined time period at start of the gas sensor, and then the temperature of the sensor element is decreased to the operating temperature.

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 computer for a vehicle, the vehicle including a heat engine, a depollution system configured to depollute the exhaust gases originating from the engine, a first probe placed between the outlet of the heat engine and the inlet of the depollution system and configured to measure a first parameter relating to the oxygen level in the exhaust gases exiting the heat engine, a second probe placed at the outlet of the depollution system and configured to measure a second parameter relating to the oxygen level in the exhaust gases exiting the depollution system. The computer being configured to receive the values measured by the first probe and by the second probe over a predefined measurement time interval and to diagnose clogging of the first probe.

An exhaust gas purification device includes: an actual pressure difference obtainer that acquires an actual pressure difference which is an actual measurement value of a pressure difference of a filter; a flow rate obtainer that acquires a flow rate of exhaust gas flowing into the filter; a calculation pressure difference calculator that calculates a calculation pressure difference which is a calculated value of the pressure difference of the filter in a normal state when the exhaust gas flows into the filter with the flow rate acquired by the flow rate obtainer; and an abnormality determiner that performs an abnormality determination of the filter based on a pressure difference variation ratio which is a ratio between a variation in the actual pressure difference and a variation in the calculation pressure difference in response to a variation in the flow rate of the exhaust gas.

Temperatures of exhaust gas upstream and downstream of an oxidation catalytic converter in an exhaust gas line of an internal combustion engine are measured and the differences analyzed to detect a leakage in the EGR evaporator.