Method and device for processing a signal supplied by a sensor for measuring the pressure existing in a cylinder

Abstract

The invention relates to a method and device for processing a signal supplied by a sensor for measuring the pressure existing in a cylinder, and relates to a method of processing a periodic voltage signal, called the input signal, relating to the pressure existing in a combustion chamber of a cylinder of an internal combustion engine. The method includes a step (E6) of determining a second instant of unlocking of the base signal during a second peak phase, a step (E7) of determining a second instant of locking, which is subsequent to the second instant of unlocking and for which the input signal is in the plateau phase consecutive to the second peak phase, and a step (E8) of generating a base signal between the second instant of unlocking and the second instant of locking on the basis of a slope value of a straight line determined during a first peak phase between a first instant of unlocking and a first instant of locking during a first peak phase.

Description

technical field [0001] The invention relates to the field of gas pressure measurement in cylinders of internal combustion engines, and more particularly to a method and a device for processing the signal supplied by a pressure measurement sensor in order to compensate for its offset. Background technique [0002] Internal combustion engines generally include a plurality of cylinders, each cylinder forming a combustion chamber into which a fuel and an oxidant are introduced to cause the mixture to combust. In such engines, there is a known way to equip each cylinder with a sensor for measuring the pressure present in the combustion chamber. This pressure-measuring sensor comprises a piezo-sensitive element which, in a known manner, uses changes in electrical charge to provide an indication of the pressure present in the cylinder in a relative manner. Sensors generate voltage signals representing these pressure changes and supply them to the vehicle's engine control computer ...

AI Technical Summary

Problems solved by technology

[0009] However, it has been found that when there are large changes in engine speed (sharp acceleration or sharp deceleration when the driver lifts his foot from the accelerator pedal) or when there are temperature changes (where the piezoelectric element of the sensor generates pyroelectricity) , can make the basic signal S_base unstable

This is because: during these changes, if image 3 As shown in , the input signal can be overcompensated (I) or undercompensated (II), so that the end of peak P2 is detected when the value of the input signal S_in is too high M or too low N, resulting in an excessive slope of the fundamental signal Large variations, and thus incorrect compensation of the input signal S_in

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