When a diesel engine is determined to be in a motoring state, a hysteresis zero angle H.sub.0 is determined (step S14). Subsequently, a gradient d.sub.n is calculated (step S16). The gradient d.sub.n is calculated based on data (θ.sub.n, Δh.sub.n) of a deviation Δh.sub.n at a retardation side from the hysteresis zero angle H.sub.0 and at an advance side from a predetermined crank angle. Subsequently, the gradient d.sub.n and the hysteresis zero angle H.sub.0 are updated (step S18). When the diesel engine is determined to be in a non-motoring state, data (θ.sub.n, P.sub.n) of an actual in-cylinder pressure is corrected based on a newest correction coefficient η and hysteresis zero angle H.sub.0 (step S22).

A method and apparatus for compensates for oxygen sensor aging determines a correction of by measuring oxygen content above a specified threshold value and measuring current flowing through the sensor over time.

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 for operating a controller for a position transducer system, of a throttle valve position transducer in an engine system having an internal combustion engine, the control being performed to obtain a manipulated variable for triggering an actuating drive of the position transducer system, the control being performed by initially applying a transfer function to a system deviation to obtain an adapted system deviation and subsequently applying a transfer function to the adapted system deviation to obtain the manipulated variable, the transfer function being a function which indicates a deviation of a model of a nominal position transducer system having predefined nominal parameters from the model of the position transducer system to be controlled, an adaptation of the control process being performed by adapting the transfer function, in that the parameters of the model of the position transducer system to be controlled are adapted, in particular in real time.

A method for checking the association of structure-borne noise sensors of an internal combustion engine having a plurality of cylinders, which internal combustion engine can be operated in diesel operation or with individualized gas injection and in the case of which internal combustion engine a structure-borne noise sensor is arranged in the region of each cylinder, wherein the output signals of the structure-borne noise sensors reflect a knock index and are captured by a computing unit, wherein the internal combustion engine is operated in order to perform the method. The output signals of all structure-borne noise sensors are determined during at least one working cycle, which is formed by two revolutions of a crankshaft, in the respective positions of the crankshaft. The output signal of a cylinder is compared with the average value or the median value of the output signals of other cylinders.

A method for calibrating a drive of a throttle valve of an internal combustion engine of a motor vehicle includes detecting whether the internal combustion engine is currently running or is not running. The method further includes activating the drive to displace the throttle valve into a target position if it is detected that the internal combustion engine is currently not running. The method further includes calibrating a characteristic at the target position. A correlation between a rotor position of the drive and an output voltage of a throttle valve angle transducer follows a characteristic.

Methods and systems for calculating a plurality of aging factors in a system operating an engine. The calculated aging factors may include one or more of fuel injector drift, exhaust gas recirculation valve obstruction, and mass air flow sensor bias. Mass flow throughout the system, and pressures and temperatures within the system, are observed in an approach that relies on mass preservation concepts to estimate fuel injector drift, exhaust gas recirculation valve obstruction, and mass air flow sensor bias.

Disclosed is a method for acquiring an altitude correction coefficient, comprising: acquiring an initial value of an altitude correction coefficient self-learning filter when a preset event occurs to a vehicle engine, the preset event includes a power-off event, a power-on event, and an unexpected power-down event; evaluating whether the vehicle satisfies a preset self-learning enabling condition, in accordance with an engine rotation speed, a vehicle speed, and status information of designated devices; enabling the altitude correction coefficient self-learning filter when the vehicle satisfies the preset self-learning enabling condition; determining an input of the altitude correction coefficient self-learning filter at least in accordance with operating states of a manifold pressure sensor and a stepping motor; and obtaining a current altitude correction coefficient by self-learning the altitude correction coefficient applying the altitude correction coefficient self-learning filter in accordance with the initial value of the altitude correction coefficient self-learning filter and the input of the altitude correction coefficient self-learning filter. An apparatus for acquiring an altitude correction coefficient is also disclosed. The above method and apparatus improve the accuracy of the altitude correction coefficient and enhance the idling satiability.

A control device for an internal combustion engine controls a control object device based on an output value of a relative angle sensor that detects a relative angle of an output shaft of an actuator, and an output value of an absolute angle sensor that detects an absolute angle of a drive shaft coupled to the output shaft of the actuator via a speed reducer. In this event, the control device for the internal combustion engine corrects an output value of the absolute angle sensor based on an absolute angle of the drive shaft that is obtained from an output value of the relative angle sensor using, as a reference point, an output value of the absolute angle sensor at the start-up of the internal combustion engine, and an output value of the absolute angle sensor.

There is provided a controller and a control method for an internal combustion engine capable of correcting a detection error of a crankshaft angle with high accuracy. The controller of the internal combustion engine is provided with an angle information detection unit that detects an angle interval and a time interval with a specific crank angle sensor, an angle information correction unit that corrects the angle interval or the time interval by the correction value, an angle information calculation unit that calculates a first crank angle acceleration based on the corrected values of first interval number and calculates a second crank angle acceleration based on the corrected values of second interval number which is larger number than the first interval number, and a correction value change unit that changes the correction value so that the first crank angle acceleration approaches the second crank angle acceleration.