| 摘要 |
PROBLEM TO BE SOLVED: To prevent the malfunction of a middle position lock pin. SOLUTION: A vane type variable valve timing mechanism is provided in an internal combustion engine, and a middle position lock pin 230 is provided in a vane body of the mechanism. Further, a middle position lock hole 231 is provided at a position matched with the middle position lock pin 230 in a middle valve timing between a most timing retard position and a most timing advance position of a housing of the mechanism. Oil-pressure passages 237, 239 which connect lift oil-pressure passages 233, 235 lifting the lock pin 230 to a lock hole 231 only when the vane body is located at a middle position are provided. When the lock pin 230 is lifted, a lift oil pressure is also supplied via the oil-pressure passages 237, 239 to the lock hole 231 at the time when the vane body passes through the middle position, whereby the lock pin 230 is prevented from engaging with the lock hole 231 due to malfunction. |
