The Effects of supercharging on the Performance and Exhaust Gas Emission of a Dualfuel Multi-cylinder Diesel Engine with Bio-mass gas- Diesel and soybean oils Blends

Abstract

The effects of Bio-ass gas-diesel and soybean oil blends on the performance and exhaust emissions of a supercharged dual-fuel
multi-cylinder diesel engine have been experimentally investigated. In this study, Bio-mass gas that was generated from a
downdraft gasifier and intake air by air compressor were injected separately into the engine intake manifold. The pilot fuel
injection timing was advanced to 22° before top dead centre and the primary fuel injection pressure was maintained at 2.5 bars
throughout the experiment. The soybean oil was blended with diesel fuel at 5%, 50, 75 and 100% volume ratios. The experiments
were carried out by varying the injection flow rate of both the Bio-mass gas and the air at different engine loads and at constant
engine speed. It was observed that at 70% engine load, the brake thermal efficiency of 20% soybean oil blends was 20.10% as
compared to the percentage in Bio-mass gas-diesel dual fuel that was 21.38% and 24.11% in diesel fuel. Emissions of CO and
NOx were 0.42% and 230 ppm as compared to 0.38 and 208 ppm in Bio-mass gas-diesel duel fuel operation. These showed that
the engine performance of the Bio-mass gas-diesel and soybean oil blends were reduced and the emission characteristics were
increased at the rated loads compared with the Bio-mass gas-diesel fuel. This is mainly due to the lower calorific value, high
viscosity and higher density of the soybean oil compared with diesel fuel. Based on critical analysis of the graphs, the 25%
soybean oil with 75% diesel mixture is the best-suited blend for the dual-fuel mode of the Bio-mass gas-diesel engine without a
preheating process and engine modifications. Therefore, the experimental results indicate that soybean oil can be used as an
alternative to diesel in supercharged dual-fuel Bio-mass gas engines.