Fuel Injection Pressure and Combustion Chamber Geometry Effects on the Performance and Emission Characteristics of Diesel Fueled CI Engine with EGR

Abstract

Nowadays automotive industries and IC engine researchers are highly in verge of developing clean emission technologies with lower fuel consumption. The swirl chamber creates a pollution-free environment and eventually reduces the usage of fossil fuels. The time required for fusing the air and fuel, in a water-cooled direct injection diesel engine, is of the order less than 10 ms. In this research, the burn rate of the engine is enhanced by modifying piston bowl design of a swirl chamber. Three modified piston bowl designs namely: chamber-A (CH-A), chamber-B (CH-B) and chamber-C (CH-C), that uses diesel as the primary fuel were developed with a focus on reducing harmful exhaust emission while maintaining high brake thermal efficiency (BTE) and low specific fuel consumption (SFC). The present investigation examines the impact of injection pressures on performance, emission and combustion characteristics of the single cylinder four-stroke direct injection CI diesel engine (Variable compression ratio [VCR] engine) with these three piston bowl designs. In the current exploration, direct injection diesel engine, at 1500 rpm, with varied fuel injection pressures (IP) (600–1400 bar) and 15% EGR were studied using Diesel-RK simulation tool and the results were analyzed against the experimental values. From the simulation result, the specific fuel consumption (SFC) and nitrogen oxide (NOx) of chamber-A was slightly higher than the other two chambers and simultaneous decrease in particulate matter (PM) and ignition delay (ID) with and without EGR mode was observed. Furthermore the results indicated that EGR led to an increase in SFC and BTE. The experiments were performed using chamber-A and standard piston bowl design with and without exhaust gas recirculation (EGR) mode. With 15% of EGR, the percentage decrease in BTE was up to 2% at quarter load condition and nearly the same at full load condition. The EGR caused a reduction in exhaust gas temperature. Thus, it has a potential to reduce 60% of NOx discharge at full load condition and simultaneously rises the SFC, PM & ID marginally.