Patent attributes
A bypass controller (30) controls ON/OFF of a three-way electromagnetic valve (62) according to a detection value of a cam chamber sensor (12a). When the cam chamber sensor (12a) detects a viscosity of lubricant exceeding a predetermined allowable value, the three-way electromagnetic valve (62) is controlled to turn ON so that the output side of an oil separator (13) communicates with a bypass route (61). The pressure in the cam chamber (12) is reduced to or below the atmospheric pressure by suction of a compressor (16) with a check valve (14) regulating the pressure in the cam chamber (12) to the atmospheric pressure or above in the bypassed state. When the detection value of the viscosity of the lubricant output by the cam chamber sensor (12a) has become the predetermined allowable value or below, the three-way electromagnetic valve (62) is controlled to turn OFF so that the output side of the oil separator (13) communicates with the check valve (14) and the bypass route (61) is cut off.
