The Effect of Compression Ratio on Engine Performance and Exhaust Emissions Using DTBP-Heptane Blends

摘要

The effect of compression ratio on engine performance and exhaust emissions in a single cylinder research engine operating with n-heptane and n-heptane/di-tertiary-butyl peroxide (DTBP) blends was examined. The effects on autoignition timing and on exhaust temperature and emissions are reported. In general increasing compression ratio decreases ignition delay, exhaust temperature, and the exhaust concentrations of carbon monoxide and total unburned hydrocarbons. It was also observed that there is an additional reduction in these parameters using blends of n-heptane with 1.5% or 3% DTBP. Based upon previous studies of DTBP and n-heptane, the reduction in these parameters is attributed to the increase in mixture temperature due to the decomposition of DTBP. The results of this work suggest that engine operating conditions will impact the effectiveness of DTBP addition. Specifically, DTBP addition has a relatively large effect at lower compression ratios and engine speeds, but it has almost a negligible effect at the highest compression ratio.