In this paper the authors used the dual fuel method to experiment with the use of LPG, mainly butane, as the main fuel of diesel engines to reduce soot and to maintain high thermal efficiency. LPG wasinjected in the direction of the intake valve directly as a spray to prevent knocking and to maintain high charging efficiency. The newly developed electronic fuel injection provided accurate fuel control and injection timing. As a result, the dual fuel operation produced high thermal efficiency almost identical to that of diesel engines. Soot in the engine exhaust was almost negligible. The mean effective pressure of 0.6 MPa was obtained with LPG and only a small amountof gas oil, in spite of the high compression ratio of 17 for gas engines. Increasing the proportion of gas oil resulted in maximum output from the engine and almost no soot output. Moreover, mordenite catalyser reduced by 20% the NOx in the exhaust gas, and THC functioned as a reducing agent for NOx simultaneously
Abstract