| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a variable valve system of an internal combustion engine that detects abnormal conditions of phase oscillation. <P>SOLUTION: The variable valve system includes: a hydraulic variable valve timing mechanism; and an advance chamber and a retard chamber which are formed between a housing rotor and a vane rotor, the rotors constituting the mechanism. The variable valve system further includes: a retard oil pressure sensor for detecting an oil pressure of the retard chamber; and an advance oil pressure sensor for detecting an oil pressure of the advance chamber. In addition, when a phase remaining control is performed and an oil pressure difference DP between the maximum value P3 of an advance-chamber oil pressure PS and the maximum value P4 of a retard-chamber oil pressure PT is larger than a reference value, the system determines that the abnormal conditions of the phase oscillation has occurred. <P>COPYRIGHT: (C)2012,JPO&INPIT |
