Technical Paper
Fuel Composition Effects on Hydrocarbon Emissions from a Spark-Ignited Engine - Is Fuel Absorption in Oil Significant?
1995-10-01
952542
Absorption of fuel in engine oil layers has been shown to be a possible source of hydrocarbon (HC) emissions from spark-ignited engines. However, the magnitude of this source in a normally operating engine has not been determined unambiguously. In these experiments, a series of n-alkanes of widely different solubility (n-hexane through undecane) was added (1.5 wt % each) to a Base gasoline (CA Phase 2). Steady-state experiments were carried out at two coolant temperatures (339 and 380 K) using a single-cylinder engine with the combustion chamber of a production V-8. Both total and speciated engine-out HC emissions were measured. The emissions indices of the heavier dopants did not increase relative to hexane at either coolant temperature.