The Effects of Supercharging on the Performance and Exhaust Gas Emissions of a Dual-Fuel Engine Fueled with Producer Gas-Diesel and Palm Oil Blends

The effects of producer gas-diesel and vegetable oil blends on the performance and exhaust
emissions of a supercharged dual-fuel single-cylinder diesel engine have been experimentally investigated. In
this study, producer gas that was generated from a downdraft gasifier and intake air were injected separately
into the engine intake manifold. The pilot fuel injection timing was advanced to 23° before top dead centre and
the primary fuel injection pressure was maintained at 2 bar throughout the experiment. The vegetable oil was
blended with diesel fuel at 2%, 50, 75 and 100% volume ratios. The experiments were carried out by varying the
injection flow rate of both the producer gas and the air at different engine loads and at constant engine speed.
It was observed that at 80% engine load, the brake thermal efficiency of 25% vegetable oil blends was 20.10%
as compared to the percentage in producer gas-diesel dual fuel that was 21.38% and 24.11% in diesel fuel.
Emissions of CO and NOx were 0.43% and 232 ppm as compared to 0.39 and 210 ppm in producer gas-diesel duel
fuel operation. These showed that the engine performance of the producer gas-diesel and vegetable oil blends
were reduced and the emission characteristics were increased at the rated loads compared with the producer
gas-diesel fuel. This is mainly due to the lower calorific value, high viscosity and higher density of the
vegetable oil compared with diesel fuel. Based on critical analysis of the graphs, the 25% vegetable oil with 75%
diesel mixture is the best-suited blend for the dual-fuel mode of the producer gas-diesel engine without a
preheating process and engine modifications. Therefore, the experimental results indicate that vegetable oil can
be used as an alternative to diesel in supercharged dual-fuel producer gas engines.