Investigation of Hydrocarbon Emissions from a Direct Injection-Gasoline Premixed Charge Compression Ignited Engine

The causes of Unburned Hydrocarbon (UHC) emissions from a premixed compression ignited engine were investigated for both homogeneous and stratified charge conditions. A fast response Flame Ionization Detector (fast FID) was used to provide cycle-resolved UHC exhaust emission measurements. These fast FID UHC measurements were coupled with numerical flow simulation results to provide quantitative and qualitative insight into the sources of UHC emissions. The combined results were used to evaluate the effects of engine load, local gas temperatures, fuel stratification, and crevice quenching on UHC emissions.