To surely adjust cam shaft even at the time of starting an engine by appling pressure load to a cam shaft adjusting device by an oil pressure circuit of a steering assist mechanism in the engine start stage, and by a lubricating oil pressure circuit peculiar to the engine in the other operation stage.
A cam shaft adjusting machine 3 is connected to two oil pressure circuits through a 4-port three-position proportional valve 10. One is a serve oil circuit 11 for assisting steering, and the other is a lubricating oil pressure circuit 12 peculiar to the engine corresponding to the internal combustion engine. Both oil circuits are separated from each other by a check valve 13. When the internal combustion engine is started, all oil pressure of the steering assisting circuit or the serve oil circuit 11 is utilized for adjusting the cam shaft. Before the engine is started, generally the steering operation is not needed. Accordingly, before the engine is started, the cam shaft can be turned to a desired position at every time.
HEINTZEN DIRK
BREUER KLAUS-JOERG
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