EFFECTS OF WATER EMULSIFIED B5-DIESEL AND BIOGAS ON THE COMBUSTION AND EMISSIONS OF RCCI ENGINE AT LOW LOAD

Abstract

An experiment was conducted to investigate the effects of water in biodiesel emulsions (WiBE) and biogas on the reactivity-controlled compression ignition combustion for improved performance and reduced emissions. 13% WiBE, 15% WiBE and regular B5 were, directly, injected with the port injection of biogas at the intake valve, as a modified fueling approach. An advanced injection timing of 21o CA BTDC and energy fraction of 50% each of the fuels, were maintained at a speed of 2000 rpm and vary the load from 4.5 to 6.5 bar IMEP. The combustion of WiBE and biogas had been found disadvantageous to the rise in the cylinder pressure and heat released at high load but highly beneficial in reducing peak pressure rise rate besides lowering the in-cylinder temperature as a useful tool for low-temperature combustion technique. The use of WiBE and biogas resulted in a retarded combustion phase while B5 demonstrated more delayed combustion. Both 13% and 15% water emulsions exhibited similar carbon dioxide emission attributes but remained higher compared to the regular B5 at all the engine capacity except 6.5 bar IMEP. The fuels reactivity lowers significantly, the in-cylinder temperature causing elevated carbon monoxide (CO) and unburned hydrocarbon (UHC) emissions, by 41.09% and 19.61% respectively, along with the reduced nitrogen oxides emission by 50.85%. Use of strategies to raise the in-cylinder temperature may cut down the challenging emissions