Pressure measuring device and corresponding method

A device for measuring the cylinder pressure of an internal combustion engine that operates with a plurality of successive cycles, each cycle being broken down into at least first and second strokes, the measuring device comprising:

• at least one pressure sensor (1) comprising at least one piezoelectric element associated with a capacitive element, and an output (10) generating a first voltage (V1) representative of a pressure (F) applied to the piezoelectric element;
• a filtering module (2) comprising at least one input (20) and one output (21), capable of filtering parasitic low-frequency voltages present at its input (20), and of generating on its output (21) a second voltage (V2) free of these parasitic low-frequency voltages;
• a control module (3) capable of delivering a control signal (Scom) that is dependent on a switching parameter correlated with a stroke, among the first and second strokes, in which the engine is operating;
• a switching module (4), in response to the control signal (Scom), capable of disconnecting the input (20) of the filtering module (2) from the output (10) of the pressure sensor (1) during the first stroke, and of connecting the input (20) of the filtering module (2) to the output (10) of the pressure sensor (1) during the second stroke;
• and
• an output (5) generating an output voltage (Vout) equal to the first voltage (V1) during the first stroke, and equal to the second voltage (V2) during the second stroke,
• wherein the first stroke corresponds to a compression stroke or to a combustion-expansion stroke, and in which the second stroke corresponds to an intake stroke or to an exhaust stroke.