Patent ID: 7757680

Claim:
A closed crankcase ventilation apparatus, comprising: a lower case connected to a withdrawal pipe; a middle case comprising a body mounted in the lower case, an upper plate coupled with an upper end of the body, and a cup formed on an upper surface of the upper plate, the upper plate being provided with a blow-by gas passageway in the cup for flowing blow-by gas into the body therethrough and at least a gas hole formed in the upper plate outside the cup for flowing the blow-by gas in the body to the exterior of the cup; a filter mounted at a lower portion of the blow-by gas passageway and filtering engine oil contained in the blow-by gas wherein the filtered engine oil is withdrawn through the withdrawal pipe; an inlet pipe connected to a portion of an exterior circumference of the cup in order to flow blow-by gas of the inlet pipe into the cup; an outlet pipe fluidly communicating with the gas hole of the middle case in order to exhaust the filtered blow-by gas in the body; an upper case having a one-side opened structure and configured to enclose an opening at an upper end of the cup; and a by-pass passageway selectively detouring the blow-by gas of the inlet pipe according to a pressure of the blow-by gas in the inlet pipe wherein the by-pass passageway is mounted at the exterior of the lower, middle and upper cases.