The use of liquefied petroleum gas (LPG) is experimented with to improve the performance of a dual fuel compression ignition (CI) engine running on Karanja oil methyl ester (KOME) blends. Diesel is used as a reference fuel for the dual fuel engine results. During the experimentation, the engine performance is measured in terms of brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC), and exhaust emission is measured in terms of carbon monoxide (CO), hydrocarbon (HC), and oxides of nitrogen ( ). Dual fuel engine with LPG showed a reduction in and smoke emission; however, it suffers from high HC and CO emission, particularly, at lower loads due to poor ignition. Comparison of performance and emissions is done for diesel and blends of KOME. Results showed that using KOME blends (10% and 20%) has improved the CI engine performance with a reduction in HC and CO emissions. 1. Introduction The depleting reserves of petroleum and concern over high levels of pollutants in vehicular exhaust have motivated the researchers towards searching for alternative energy sources with renewable nature and less polluting effect [1]. The use of alternative gaseous fuel in CI engines in dual fuel mode is increasing due to their clean combustion compared to conventional liquid fuels as well as their relatively increased availability at attractive prices [2, 3]. For substituting petroleum fuels used in internal combustion engines, fuel of bio-origin provides a feasible solution to the twin crises of “fossil fuel depletion” and “environmental degradation.” Several researchers are actively pursuing utilization of nonedible oils for the production of biodiesel worldwide because of its cleaner burning nature [4, 5]. Chemically, biodiesel is referred to as the mono-alkyl-esters of long-chain-fatty acids derived from renewable lipid sources. The principal advantages of biodiesel is that it suppresses the formation of sulphur dioxide, CO, HC, and PM emissions during the combustion process due to low sulphur, low aromatics, and the presence of oxygen-containing compounds. In addition, biodiesel has good ignition ability in engine due to its relatively high cetane number compared to that of conventional diesel fuel [6, 7]. It is found that the lower concentrations of biodiesel blends improve the thermal efficiency. As the parameters at which the engines are operating, a blend up to 20% of biodiesel with diesel works well without any modification in the engine [8, 9]. The potential benefits of using LPG in diesel engines are both economical and environment friendly
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