Study of Modified Internal Combustion Engine to Run with Ethanol

Sajag Poudel, Dipan Deb

Moving across the emerging trends of renewable energy sources, ethanol has attracted more attention because it is considered as a renewable resource and is easily obtained from sugar or starch. Moreover, ethanol fuel as an IC engine fuel would be able to solve the issue of carbon emission and environmental pollution. Ethanol can replace conventional gasoline to be used as a fuel for automotive. This paper is about the results and analysis obtained during the test of an IC engine with ethanol before and after modification. As we want to run an IC engine with ethanol, its physical and chemical properties play crucial role. Due to different physical & chemical properties of ethanol than that of gasoline, proper engine parameters should be maintained in gasoline engine to run it with ethanol i.e. the stoichiometric ratio needs to be maintained. An attempt to test gasoline based IC engine using ethanol initially didn’t give promising result in terms of efficiency and mileage. Carburetor of engine was modified so as to maintain proper stoichiometric ratio which improved the brake power of engine but with more fuel consumption; resulting to lesser thermal efficiency at the end. Finally, the optimal utilization of ethanol in the modified gasoline engine was done by changing the compression ratio of the engine. Since, ethanol has higher octane rating, it can sustain higher compression ratio and boost up the engine performance. The gasoline & ethanol (with modified carburettor) test was done in 4 stroke gasoline engine test rig and the results like brake power, specific fuel consumption and brake thermal efficiency was analysed. The loss in efficiency in case of ethanol was brought down by increasing the compression ratio of same engine. Due to some feasibility constraint, variable compression ratio (VCR) engine was used for experiments rather than changing the compression ratio of the engine itself.