Device for determining an error induced by a high-pass filter and associated error correction method

A conditioner for a sensor having a high-pass filter, the conditioner comprising:

• a device for determining an error induced by the high-pass filter in a measurement signal, the device comprising:
• a processing device, and
• a means for calculating said error according to the formula:
• E(t)=Ve(t)−Vs(t)=2·Π·Fc·∫α=t0t(Vs(α)− Vs(α))·dα+E(t0)
• with:
• E(t) the value of the error induced by the high-pass filter, as a function of the time variable t,
• Π the trigonometric constant,
• Fc the cutoff frequency of the high-pass filter,
• t0 the initial instant,
• α an integration variable,
• Ve the signal input to the high-pass filter,
• Vs the signal output by the high-pass filter,
• Vs the mean value of the signal Vs,
• the processing device being configured to cause the means for calculating the error to calculate the error according to the formula;
• and
• a summator device, adding said error to the output signal Vs of the sensor, so as to produce a corrected signal Ve.

A sensor, comprising:

• a high-pass filter;
• and
• a conditioner comprising
• a device for determining an error induced by the high-pass filter in a measurement signal, the device comprising:
• a processing device, and
• a means for calculating said error according to the formula:
• E(t)=Ve(t)−Vs(t)=2·Π·Fc·∫α=t0t(Vs(α)− Vs(α))·dα+E(t0)
• with:
• E(t) the value of the error induced by the high-pass filter, as a function of the time variable t,
• Π the trigonometric constant,
• Fc the cutoff frequency of the high-pass filter,
• t0 the initial instant,
• α an integration variable,
• Ve the signal input to the high-pass filter,
• Vs the signal output by the high-pass filter,
• Vs the mean value of the signal Vs,
• the processing device being configured to cause the means for calculating the error to calculate the error according to the formula;
• and
• a summator device, adding said error to the output signal Vs of the sensor, so as to produce a corrected signal Ve.

A method of measuring the pressure in an internal combustion engine cylinder, the method comprising:

• measuring the pressure by a pressure sensor, using a piezoelectric sensitive element fitted to the sensor, the sensor comprising
• a high-pass filter;
• and
• a conditioner comprising
• a device for determining an error induced by the high-pass filter in a measurement signal, the device comprising:
• a processing device, and
• a means for calculating said error according to the formula:
• E(t)=Ve(t)−Vs(t)=2·Π·Fc·∫α=t0t(Vs(α)− Vs(α))·dα+E(t0)
• with:
• E(t) the value of the error induced by the high-pass filter, as a function of the time variable t,
• Π the trigonometric constant,
• Fc the cutoff frequency of the high-pass filter,
• t0 the initial instant,
• α an integration variable,
• Ve the signal input to the high-pass filter,
• Vs the signal output by the high-pass filter,
• Vs the mean value of the signal Vs,
• the processing device being configured to cause the means for calculating the error to calculate the error according to the formula;
• and
• a summator device, adding said error to the output signal Vs of the sensor, so as to produce a corrected signal Ve.

A method of correcting an error induced by a high-pass filter in the measurement chain of a sensor, said method comprising:

• estimating the error induced by the high-pass filter as a function of the characteristics of said high-pass filter by using a means for calculating said error of the type
• E(t)=Ve(t)−Vs(t), with
• E(t) being the value of the error induced by the first-order high-pass filter, as a function of the time variable t, Ve(t) being the signal input to the high-pass filter as a function of the time variable t, and Vs(t) being the signal output by the high-pass filter as a function of the time variable t;
• and
• correction of the error induced by the high-pass filter,
• wherein a processing device is configured to cause the means for calculating the error to calculate the error.