Host: The Japan Society of Mechanical Engineers
Name : The Ninth International Conference on Modeling and Diagnostics for Advanced Engine Systems (COMODIA 2017)
Date : July 25, 2017 - July 28, 2017
A validation study on the chemical reaction models for heptane-isooctane mixing fuel as a primary reference fuel of gasoline (PRF) and heptane-toluene mixing fuel (TRF) was performed by using repetitive compression-expansion reactor (RCER). The mechanism of RCER is similar to a motoring engine, however, the concentration of sample gas in the reactor is regulated like a conventional rapid compression machine (RCM). Experimental conditions were set as follows. The values for initial pressure and temperature were set to 30, 40 kPa and 360 K, respectively. Engine speed was set to 600 rpm. Maximum pressure in the reactor reached about 1 MPa from an initial pressure as 30 kPa by compression of air. The dimension of RCER is as follows. Displacement volume is 382 cm3 and the compression ratio is 27.5. The initial gas mixtures are charged homogeneously in the reactor and compressed for auto-ignition, that is, the HCCI condition. The ignition timing was delayed by increasing the mixing fraction of isooctane or toluene. Comparing the results and simple chemical kinetics simulations was also performed with two reaction models in the literature. Both models showed similar trends of the delay times as well as the experimental results. However, the retarding effect of a higher fraction of toluene in the fuel mixtures was overestimated in one model despite good agreement each other in the case of heptane alone. It suggests that the toluene reaction model has some problems for the conditions in this study.
