Quench Layer Contribution to Exhaust Hydrocarbons from a Spark-Ignited Engine

INTRODUCTION

Hydrocarbons remaining in a wall quench layer have been proposed as a major source of hydrocarbon emissions in spark-ignited internal combustion engines (Daniel and Wentworth, 1962). Additional experiments using wall mounted sampling valves were subsequently carried out by Daniel (1967), Müller and von Watzdorf (1968), Weiss et al. (1979), and Henningsen and Qvale (1980). Our paper presents the results of an experimental study of the quench layer also using a wall mounted sampling valve. The valve was electrohydraulically actuated and had uniquely small leakage and crevice characteristics. Our results do not support the contention that the wall quench layer is a major source of exhaust emissions. Hydrocarbons from other sources, as yet not quantified, such as those emitted from ring crevices, deposits or oil films appear to be likely contributors to exhaust hydrocarbons (Wentworth, 1971; Haskell and Legate, 1972; and Kaiser et al., 1980).