Emission reduction in diesel engine with acetylene gas and biodiesel using inlet manifold injection

Abstract

It is well known that acetylene has a wide flammability and is readily available and low-cost non-crude oil derivative fuel. According to the property of low motor octane number, the acetylene cannot be used alone in the internal combustion engine. Research has shown that the introduction of biodiesel results in a substantial reduction in the use of conventional fossil fuels and also in the amount of emissions. This study focuses on performance improvement and emission reduction of conventional diesel engine using acetylene gas as a low-reactivity fuel (LRF) and B20 mahua biodiesel as a high-reactivity fuel (HRF) in the reactivity controlled compression ignition (RCCI) mode. The computational fluid dynamics (CFD) principle is used to evaluate the optimal angle of the LRF injector to achieve better fluid flow mixing pattern in the inlet manifold. From the CFD simulation, an optimal LRF injection angle of 45° is defined in the intake manifold. The modified intake manifold engine is tested for performance, emission and combustion characteristics at different flow rates of acetylene through the injector. It is observed that the brake thermal efficiency (BTE) is increased by about 3.7% at a flow rate of 4 liters per minute (LPM) of acetylene injection in RCCI combustion mode compared to conventional biodiesel operation and significant decreases in polluting components such as smoke opacity, oxides of nitrogen (NOx), hydrocarbon (HC) and carbon monoxide (CO) are reduced by about 10%, 7.6%, 13.4% and 28.7%.