Heat Release Analysis on Combustion and Parametric Study on Emissions of HCCI Engines Fueled with 2-Propanol/n-Heptane Blend Fuels

Abstract

This article investigates the inhibition effects of a 2-propanol additive on n-heptane homogeneous charge compression ignition (HCCI) combustion, analyzes the relationship between the emissions with the combustion parameters and fuel component, and evaluates the influence of cold exhaust gas recirculation (EGR) on HCCI combustion and emissions. The experiments were conducted on a single-cylinder HCCI engine using neat n-heptane and 10∼60% (by volume) 2-propanol/n-heptane blend fuels at 1800 rpm. The experimental results reveal that the ignition timing of the low-temperature reaction (LTR) is retarded, and the peak values of heat release during the LTR are decreased with an increase of 2-propanol in blend fuels. As a result, the ignition timing of the high-temperature reaction is delayed, both the maximum and lowest indicated mean efficient pressures (IMEP) are increased, and the combustion efficiency is also decreased. Parametric studies on CO and HC emissions show that the fuel volume with a high cetane ...