A 1.9L four cylinder engine was evaluated for leakage of cylinder charge through the exhaust valve seats. Fast FID HC analyzer traces reveal leakage. Static leakdown tests do not correlate with the Fast FID measurement, unlike previously published reports for a different engine. The causes of exhaust valve seat leakage are likely to be Because deposit related effects are very history dependent, it is very difficult to obtain quantitative results.Some experimental observations: A brief survey of several other engines indicated the presence of leaks. It is likely that most engines exhibit exhaust valve seat leakage at least at some times.It is difficult to assess the effect of these leaks on exhaust hydrocarbon emissions because of the complexity of the engine history dependence. Limited data suggest a 5% contribution is possible.
Exhaust Valve Seat Leakage
Sae Technical Papers
International Spring Fuels & Lubricants Meeting & Exposition ; 1997
01.05.1997
Aufsatz (Konferenz)
Englisch
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