Experimental study of butanol blending in biogas-biodiesel fueled CI engine under dual fuel, RCCI and HCCI combustion modes

Advancement in global emission policies and competitive market demands for fuel-efficient vehicles enforce challenges over the usage of internal combustion engines. Greenhouse and other pollution gases which could emanate from engine combustions can be controlled by supplying right fuel at the choice of operating modes. In the present research, impact of butanol blending into the secondary fuel on the performance of a CI engine is studied, under three different modes of combustion viz., dual fuel, Reactivity Controlled Compression Ignition (RCCI) and Homogeneous Charge Compression Ignition (HCCI) modes. Here, a stimulated biogas comprising methane and carbon-dioxide is supplied at a constant flow rate as a supplement for diesel fuel and the engine loads are varied from 0 to 20 N -m. The study revealed that the blending of butanol affected the brake thermal efficiency under RCCI combustion, however blending with B20 biodiesel/DEE under HCCI and dual fuel modes resulted significant improvement in the efficiency. Dual fuel combustion is observed to have full potential to utilize the biogas energy among the three. Among the three, RCCI resulted large NOx and smoke emissions, whereas the HCCI proved to have lower emissions. Dual fuel combustion is found with less HC and CO emissions.