Influence of injection strategy and combustion chamber geometry on the performance and emissions of a bio-ethanol fuelled CRDI diesel engine

Abstract

Owing to the growing depletion of fossil fuels and increasing environmental impacts, alternative fuels such as bio-ethanol are becoming more attractive for use in compression ignition (CI) engine. The current study examines the impact of combustion chamber geometry and injection pressure on improving performance, reducing emissions, and enhancing combustion characteristics in a bio-ethanol fuelled diesel engine. Experimental tests were performed using bio-ethanol fuel (EPMD85: 85 % Ethanol, 7% PEG, 4% MTBE & 4% DEE), in a common rail direct injection (CRDI) diesel engine. Hemispherical (HCC) and Toroidal re-entrant (TRCC-B) combustion chamber geometries have been evaluated at a compression ratio (CR) of 28.5:1 and injection pressure (IP) of 1200 bar. The results indicate that the brake thermal efficiency for EPMD85-TRCC-B (28.5:1, 1200 bar) is higher than EPMD85-HCC (28.5:1, 1200 bar) and ultra-low sulfur diesel (ULSD)-HCC (17.5:1, 220 bar), although ULSD-HCC exhibits lower specific fuel consumption (SFC) than EPMD85-TRCC-B and EPMD85-HCC. EPMD85-TRCC-B achieves substantial reduction in nitrogen oxide (NOx), carbon monoxide (CO), unburnt hydrocarbon (UBHC), carbon dioxide (CO₂) and smoke compared to EPMD85-HCC and ULSD-HCC. Furthermore, the experimental results are compared with Diesel-RK simulation data under same operating condition, confirming that the EPMD85-TRCC-B combustion chamber at an IP of 1200 bar provides improved performance and enhanced combustion and reduced emissions.