Performance and emission characteristics of biomethane-diesel dual-fuelled CI engine in the presence of exhaust gas recirculation

This paper deals with the experimental investigation of dual-fuelled CI (compression ignition) engine with the biomethane-diesel combination. The 30% and 60% energy shares of biomethane were provided to the engine along with intake air stream and the diesel fuel is injected into the combustion chamber in a conventional way. The objective of the present study was to examine the performance of biomethane fuel and to investigate the combined effect of biomethane and EGR in the dual-fuelled CI engine. It was aimed to find the difference in the effect of EGR between the straight diesel mode and the dual-fuel mode. Experimental results showed that the dual-fuel mode with biomethane has an adverse effect on BTE and CO emission. BTE is reduced by 0.9% to 3.7% in the case of 30% biomethane substitution and 2.9% to 5.3% in the case of 60% biomethane substitution for different loading conditions. EGR gives a positive response for BTE in straight diesel and both dual-fuel operations. It is observed that NOX emission decreases significantly with biomethane operation. EGR further reduces the NOX emission in the dual-fuel and in the straight diesel mode. It is also observed that EGR has an almost similar effect in the straight diesel operation and the dual-fuel operation.