A clean sweep: Crankcase ventilation system upkeep helps both engines, environment By John Baxter

摘要

Crankcase blow-by is hot gases that sneak past the piston rings. As of 2007, the U.S. Environmental Protection Agency limits nonmethane hydrocarbons to 0.14 grams per bhp-hr. Blow-by gases are rich in them because they travel through oil on the cylinder walls. To keep those hydrocarbons out of the air, crankcase ventilation systems were installed on truck diesels.