An experimental investigation of structural effects on the auto-ignition properties of two C5 esters

Ignition studies of two C5 esters were performed using a rapid compression facility. Methyl butanoate and ethyl propanoate were chosen to have matching molecular weights and C:H:O ratios while varying the length of the constituent alkyl chains. The effect of functional group size on ignition delay time was investigated using pressure time-histories and high-speed digital imaging. Low-temperature, moderate-pressure conditions were selected for study due to the relevance to low temperature combustion strategies and internal combustion engine conditions. The experiments covered a range of conditions: T = 935–1117 K, P = 4.7–19.6 atm, and / = 0.3–0.4. The experimental data are compared to previous high temperature studies and chemical modeling. A new mechanism for methyl butanoate and ethyl propanoate ignition is presented. The modeling and experimental data are in excellent agreement for methyl butanaote and yield good agreement for ethyl propanoate. 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.