| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect a foreign matter such as a deposit deposited on a cylinder internal pressure sensor, with a simple constitution, to efficiently remove the foreign matter. <P>SOLUTION: An ECU 60 generates vibration by an inverse piezoelectric effect by applying a voltage on a piezoelectric element of the cylinder internal pressure sensor 48, and acquires a vibration frequency Vb, and detects a foreign matter such as a deposit deposited on the cylinder internal pressure sensor 48 based on a deviation between the acquired vibration frequency Vb and a reference vibration frequency Va generated when the foreign matter is not deposited on the cylinder internal pressure sensor 48. Since no special structure or sensor is required for detecting deposition of the foreign matter, the system can be simplified. The foreign matter is removed only when detected, so that there is no need to unnecessarily execute control for removing the foreign matter, thereby reducing wasteful energy loss. <P>COPYRIGHT: (C)2013,JPO&INPIT |
