Patent ID: 7678169

Claim:
An oil fill cap for an internal combustion engine, said cap comprising a cap body for mounting to said engine for receiving an air/oil mixture therefrom, said cap body defining a plurality of passages therethrough, including an upstream passage and first and second downstream passages meeting at a separation junction, said cap body defining a separation zone at said separation junction and receiving said air/oil mixture from said engine through said upstream passage and sending separated air to said first downstream passage and sending separated oil to said second downstream passage, said first downstream passage directing said separated air to a first exit port from said cap body, said second downstream passage directing said separated oil to a second exit port from said cap body, wherein fill oil passes into said upstream passage without passing through said separation zone, and wherein said fill oil flows into said upstream passage in the opposite direction of flow of said air/oil mixture in said upstream passage, wherein said cap body has upper and lower necks, said lower neck being a hollow tubular member having inner and outer surfaces, said inner surface defining said upstream passage, said upper neck being a hollow tubular member having inner and outer surfaces, said inner surface of said upper neck defining a fill passage communicating with said upstream passage through said lower neck to provide an oil fill for said engine, said upper neck being closeable by a second cap, said fill passage communicating with said upstream passage without passing through said separation zone, said fill passage supplying said fill oil to said upstream passage in the opposite flow direction of said air/oil mixture in said upstream passage, wherein one of said inner and outer surfaces of said lower neck and one of said inner and outer surfaces of said upper neck are threaded, said lower neck being thread-mounted to said engine, said upper neck being thread-mounted to said second cap, wherein said outer surface of said lower neck and said inner surface of said upper neck are threaded.