OIL DRAINING DEVICE IN INTAKE SYSTEM PROVIDED WITH INTERCOOLER

PROBLEM TO BE SOLVED: To drain oil trapped in an intake system automatically without depending on electric control by using a negative pressure control valve operated according to negative pressure change of a pump, in a control valve interposed in a pipe passage for connecting a part on which oil in the intake system is trapped and a vacuum pump interlocked with an engine to each other. SOLUTION: A lower part of an intercooler 24 interposed in an intake passage 22 is formed on an intercooler tank 24a, and oil 80 which flows into the intake passage 22 is trapped therein. A vacuum pump 26 is mounted on an engine 20, the tank 24a and the pump 26 are connected to each other through a passage 28, and also a negative pressure control valve operated by negative pressure change generated by the pump 26 is interposed on the way of the passage 28 as a control valve 40. In the case where the engine 20 is started after the engine 20 is stopped for a long period, the inside of the vacuum tank 30 makes in a negative pressure condition by operation of the pump 26, a diaphragm 44 is displaced to a first chamber 45 side, the control valve 40 is opened, oil 80 is absorbed to the pump 26 side, and is discharged into an oil pan.