Positive crankcase ventilation orifice muffler

摘要

An orifice muffler is designed to minimize the sound pressure level of noise emanating from control orifices in the positive crankcase ventilation (PCV) system of an automotive vehicle engine. The muffler is formed as an elongated tube having imperforate sidewalls and inlet and outlet end walls. The outlet end wall has a single orifice sized to provide a control exhaust gas flow thorough the muffler while the inlet end wall has at least two orifices of differing sizes. The inlet orifices are operative to pass the controlled gas flow and to create destructive wave interference between the flow streams thorough the muffler to minimize noise caused by turbulent flow. Various optional features of the muffler construction are also disclosed.