Abstract: In order to determine the quality of fuel in an auto-igniting internal combustion engine, a defined fuel amount is injected at defined crank shaft angles during a deceleration fuel shut-off phase of the internal combustion engine. The thereby created crankshaft torque contribution is detected and an absolute or relative measure is determined for the fuel quality thereof.

Abstract: In a method for estimating at least one control parameter of an injection system in an internal combustion engine for a target injection quantity, the estimation of the control parameter is based on linear regression, which is determined between predefined grid points and calculated test points in an operating range of the injection system.

Abstract: In order to determine the quality of fuel in an auto-igniting internal combustion engine, a defined fuel amount is injected at defined crank shaft angles during a deceleration fuel shut-off phase of the internal combustion engine. The thereby created crankshaft torque contribution is detected and an absolute or relative measure is determined for the fuel quality thereof.

Abstract: In a method for estimating an injected quantity of fuel of an isolated injection, the segment time of the cylinder in which the isolated injection takes place is evaluated numerically by forming the second temporal derivation. With the aid of the second temporal derivation of the segment time the injection parameters are updated using test quantity-test torque characteristic map.

Abstract: In a method for detecting rotational speed of an internal combustion engine (1), a sector wheel (4) which is driven by the internal combustion engine (1) is scanned, the run of a specific segment of the sector wheel is detected, the duration of said segment-run is measured and a rotational speed value is determined therefrom, the duration of the run a specific segment is re-measured, a relative variation between two consecutive segment-runs is determined and the rotational speed value is determined therefrom.

Abstract: In the case of direct injection internal combustion engines, the problem occurs that especially the injection of a minimum amount of fuel depends in particular on different operating parameters such as the speed, the start of the injection or the rail pressure. Therefore, a method or a device is suggested in which a control unit (10) subdivides the complete range of values of at least one operating parameter into discrete sections. Subsequently, for each section, at least one operating point is specified for which a corresponding correction value depending on the operating parameter is determined and obtained. The correction value is then stored together with its corresponding operating point. This has the advantage that the correction value can be determined more accurately because interpolation can for example also be performed between two operating points.

Abstract: In a method for detecting rotational speed of an internal combustion engine (1), a sector wheel (4) which is driven by the internal combustion engine (1) is scanned, the throughflow of a specific segment of the sector wheel is detected, the duration of said segment-throughflow is measured and a rotational speed value is determined therefrom. Additionally, the throughflow of a specific part of the segment is detected before and after determination of the rotational speed value and a gradient of the duration of the partial segment throughflow is determined in order to update the rotational speed value.

Abstract: A method for detecting a preinjection picks up and evaluates a vibration signal which occurs when a nozzle needle strikes a needle seat of an injector of a direct-injection internal combustion engine operating with a preinjection and a main injection. A sensor for structure-borne noise is provided on the cylinder outer wall for detecting the vibration signal. Based on the evaluation of the vibration signal a conclusion is made on the presence or absence of the preinjection in a combustion cycle. A device for detecting a preinjection is also provided.