Methods and systems are provided for diagnosing whether one or more intake air oxygen sensors positioned in an intake of an engine of a vehicle, are functioning as desired. In one example, a method comprises injecting fuel into one or more cylinders of the engine without combustion, routing un-combusted hydrocarbons from the one or more cylinders to the intake via a crankcase ventilation system, and indicating whether the one or more intake air oxygen sensors are functioning as desired based on a response of the one or more intake air oxygen sensors. In this way, the one or more intake air oxygen sensors may be periodically diagnosed which may improve engine operation, and reduce engine degradation, particularly with regard to hybrid electric vehicles with limited engine run-time.

A fuel pressure sensor diagnosis device includes an electronic control unit configured to drive a fuel supply device during electric traveling of a hybrid vehicle, to perform determination as to whether an output of a fuel pressure sensor is within a normal range after driving of the fuel supply device is started, and to perform a diagnosis to determine whether a malfunction has occurred in the fuel pressure sensor based on a result of the determination, the normal range being an assumed range of the output of the fuel pressure sensor in a case where the fuel pressure sensor normally functions and the fuel supply pressure is a prescribed upper limit pressure.

Methods and systems are provided for waking up a powertrain control module of an engine-driven vehicle during engine soak to perform an offset test of an exhaust NOx sensor. In one example, a method includes determining a duration to delay waking up the powertrain control module based on exhaust temperature at vehicle-off, waking up the powertrain control module after the duration has expired, and then initiating heating of the NOx sensor. After the NOx sensor lights off, heating continues for an additional duration before offset testing of the NOx sensor is performed.

A preheating control for controlling an energization of a heater is executed so that a sensor element of an exhaust gas sensor is preheated within a temperature range in which no element crack caused by water occurs until a predetermined preheating period elapses after an engine starts. In performing the preheating control, first, an energization duty of the heater is set to a preheating promotion energization duty to promptly raise a temperature of the sensor element until it is determined that the temperature of the sensor element reaches a predetermined upper limit temperature. After it is determined that the temperature of the sensor element reaches the upper limit temperature, the energization duty of the heater is set so that the temperature of the sensor element is maintained at the upper limit temperature to sufficiently raise the temperature of the overall sensor element during the preheating control.

The invention relates to a control method for controlling a fuel injection system (10) of an internal combustion engine, wherein, wherein, in a fault situation of the fuel injection system (10), a camshaft angle of a camshaft (34) which drives a pump piston (32) of a high-pressure fuel pump (14) of the fuel injection system (10) is adjusted such that an injection time (tI) of injector valve (42) which injects the fuel from the fuel injection system (10) into a combustion chamber of the internal combustion engine lies in a pressure trough (50) of a pressure oscillation in a high-pressure region (16).

Methods and systems are provided for accurately inferring an exhaust temperature during steady-state and transient vehicle operation based on the duty cycle of an exhaust gas sensor heating element. A steady-state temperature is inferred based on an inverse of the duty cycle, and then adjusted with a transfer function that compensates for transients resulting from changes in vehicle speed, and load, and for the occurrence of tip-in and tip-out events. The inferred temperature can also be compared to a modeled temperature to identify exhaust temperature overheating conditions, so that mitigating actions can be promptly performed.

Methods and systems include determining a cylinder air-fuel ratio imbalance in a multi-cylinder engine. In one example, the method may include sequentially firing an engine cylinder to provide an expected air-fuel deviation and learning cylinder air-fuel ratio imbalance based on an error between an actual air-fuel ratio deviation from a maximum lean air-fuel ratio relative to an expected air-fuel deviation during a deceleration fuel shut-off event.

A method and a device for knock control of an internal combustion engine, a knock signal of a cylinder of the internal combustion engine being measured by a knock sensor and, on the basis thereof, a knock intensity is generated. The knock intensity is compared to a reference level in order to classify a combustion as a knocking or non-knocking combustion. Moreover, an arrangement is provided, which takes the level of the knock intensity into account for the determination of the reference level.

An air flowmeter is arranged in an intake passage. An air-fuel ratio sensor is arranged downstream of an addition valve in an exhaust passage. An exhaust temperature sensor is arranged downstream of a catalyst. An air amount estimating process calculates an estimated air amount based on the air-fuel ratio detected by the air-fuel ratio sensor and the fuel amount injected by a fuel injection valve. An upward displacement anomaly determining process determines that there is an anomaly in which a detected value of the air flowmeter is greater than an actual value if a logical conjunction is true of the condition that the detected value of the air flowmeter is greater than the estimated air amount by a margin greater than or equal to a specified amount and the condition that an amount by which a detected value of the exhaust temperature sensor exceeds a reference value is smaller than or equal to a predetermined amount.

A method for avoiding a measurement error of an air flow sensor for a vehicle includes an engine control unit (ECU) which predicts, in advance, occurrence of the contamination by foreign materials included in the air or condensation of moisture on a sensor measurement plate of the air flow sensor, and performs an operation for preventing the contamination by foreign materials or the condensation of moisture when the occurrence is predicted, to avoid the measurement error of the air flow sensor due to the contamination by foreign materials or the condensation of moisture on the sensor measurement plate.