| 摘要 |
PURPOSE:To stabiliz a detection signal from a piezoelectric body and to read the detection signal thereafter by preliminarily heating the piezoelectric body to a predetermined temperature at the time of cold starting of an engine. CONSTITUTION:When an ignition switch is turned ON, the temperature of cooling water running in a water jacket is detected and is output by a water temperature sensor, and the water temperature detection signal from the water temperature sensor is compared with a preliminarily set temperature by a control unit. When the water temperature is lower than the set temperature, current is supplied to a heater 10 by the control unit so as to heat a piezoelectric body 8, the temperature of which reaches a constant temperature promptly, and the piezoelectric body 8 is stabilized thereby, while the detection signal from the piezoelectric body 8 thus stabilized is read, and the combustion pressure is detected. |
