| 摘要 |
PROBLEM TO BE SOLVED: To provide a technique for suppressing the overheating of a signal wire or degradation in the accuracy of detected combustion pressure in a charge amplifier built-in type combustion pressure sensor.SOLUTION: A charge amplifier built-in type combustion pressure sensor (1) includes a sensor body (2) and a charge amplifier (3). The sensor body has a piezoelectric element (21) connected at one end to chassis ground via a housing, and detects the pressure in the combustion chamber of an engine. The charge amplifier has at least a voltage conversion unit (32) for converting the output of the sensor body to a voltage signal and a reference voltage generation unit (31) for generating a reference voltage that is supplied to the voltage conversion unit, and is energized to operate by power fed from a signal processing unit (5) provided on the outside. The reference voltage generation unit is provided with a voltage generation circuit in which a constant current circuit (311) and a resistor (312) are connected in series, the voltage generation circuit being connected at one end to a power feeding line from the signal processing unit and connected at other end to a ground-side end of the piezoelectric element. |
