Experimental investigation of the factors affecting the performance of a LPG - Diesel dual fuel engine

In a dual fuel engine a primary fuel that is generally gaseous is mixed with air, compressed and ignited by a small pilot spray of diesel as in a diesel engine. Dual fuel engines suffer from the problems of poor brake thermal efficiency and high HC emissions, particularly at low outputs. In the present experimental work, the effects of intake charge temperature, pilot fuel quantity, exhaust gas recirculation and throttling of the intake on improving the performance of a LPG-diesel dual fuel engine have been studied. Results indicate that at low outputs an increase in the intake temperature and pilot quantity is advantageous. HC level generally reduces with increase in pilot quantity and intake temperature. Exhaust gas recirculation (EGR) coupled with intake heating raises the brake thermal efficiency and lowers HC emissions. With throttling and EGR there is a significant reduction in the HC levels and an improvement in brake thermal efficiency at low loads. Results indicate a possibility of determining an optimum combination of the parameters that were investigated. Copyright © 1999 Society of Automotive Engineers, Inc.