Method for diagnosing as to signal plausibility with a speed sensor of a motor vehicle
AssigneeRobert Bosch GmbH
InventorsGerit von Schwertfuehrer, Christian Muehlbauer
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Abstract
A method is for making a diagnosis as to signal plausibility in a speed sensor of a motor vehicle. In the method, the speed sensor outputs a pulse sequence to an evaluation circuit in dependence upon the speed of the vehicle and, in a steady-state operating condition of the motor vehicle, a ratio is formed between the determined speed and an engine rpm and the ratio is averaged over a pregiven time. A plausibility is determined only when the formed mean value lies in a value range permissible for the steady-state operating condition.
Claims7
A method for making a diagnosis as to signal plausibility in a speed sensor of a motor vehicle, the method comprising the steps of:
- causing said speed sensor to output a pulse seguence to an evaluation circuit in dependence upon the speed of the vehicle;
- in a steady-state operating condition of said motor vehicle, repeatingly forming a ratio between a determined speed and a motor rpm during a pregiven time and computing the mean value of the ratios formed over said pregiven time;
- and,
- only determining said signal plausibility when said mean value lies in a value range permissible for the steady-state operating condition.
A method for making a diagnosis as to signal plausibility in a speed sensor of a motor vehicle, the method comprising the steps of:
- causing said speed sensor to output a pulse sequence dependent upon the speed of the vehicle;
- supplying said pulse sequence to an evaluation circuit wherein a speed of the vehicle is determined from said pulse sequence to provide a determined speed;
- causing an rpm sensor to supply an rpm signal to said evaluation circuit indicative of motor rpm;
- repeatingly forming a ratio of said determined speed and said motor rpm during a pregiven time and computing the mean value of the ratios formed over said pregiven time;
- and,
- only determining said signal plausibility when said mean value lies in a value range permissible for the steady-state operating condition.
Dependencies are inferred from the claim text.