Hidria Aet Druzba Za Proizvodnjo Vzignih Sistemov in Elektronike D.o.o.

Hidria Aet D.o.o.

Integra Metering Ag

Marcel Guwang

Alain Ramond

A sensor includes a piezoelectric detector () mounted in a support having electrically conductive walls forming a mechanical ground (MM), and an amplifier for processing the signal delivered by the piezoelectric detector, defining an electronic ground (ME) and at least a capacitive feedback loop (). A voltage adder circuit () is inserted into the capacitive feedback loop in order to add an electrical voltage which varies as a function of the potential difference between the mechanical ground (MM) and the electronic ground (ME), so that the variations of this potential difference are continuously compensated for at the input () of the processing amplifier () receiving the signal delivered by the piezoelectric detector ().

Sensor comprising a piezoelectric detector with compensation for ground faults

A method and a circuit for processing a signal supplied by a piezoelectric sensor () indicating the cylinder pressure of a piston engine such as a heat engine. Undesirable variations in the value of the signal supplied by the sensor and corresponding to plateaux in the pressure are compensated by a closed-loop servo control which is suitable for setting an output signal to a predetermined constant reference value, independently of undesirable variations in the signal from the sensor (). The value of the output signal is sampled, and at each sampling moment, if the absolute value of the variation in the output signal is less than a comparison value, the servo control is kept active. A circuit for processing and a pressure-measuring device including a circuit of this kind is also described.

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Lacroix-Falgarde, France

Marcel Guwang