Performance and emission evaluation of dual fuel CI engine using preheated biogas-air mixture

In this work, the effect of the preheated biogas-air mixture in a biogas-diesel dual fuel CI engine was evaluated. The intake biogas-air mixture was heated by engine exhaust gas using a double pipe heat exchanger. A single-cylinder, air-cooled CI engine was modified to run in dual fuel mode. The research was carried out at various biogas-air mixture intake temperatures ranging from 55 ± 5 °C to 85 ± 5 °C under different loading conditions. The obtained results were compared for the diesel mode and non-preheated biogas-diesel dual fuel mode. The results revealed that the brake power and the brake thermal efficiency were found to be 6.5% and 51.4% enhanced by raising the intake temperature compared to the non-preheated biogas-air mixture. Moreover, preheating the inlet biogas-air mixture reduced 40.5% of the brake specific biogas consumption and 7.25% of brake specific diesel consumption. On contrary, CO₂ and NO_x emissions for preheated BAM increased by 12.6% and 11.73%, respectively, compared to non-preheated BAM. Preheating the inlet biogas-air mixture reduced HC and CH₄ emissions. The preheated biogas-air mixture at 75 ± 5 °C gave the optimum performance characteristics. The promising experimental results would help to develop biogas-diesel operated dual fuel engine.