Effect of injection parameters on the hydrogen enriched dual-fuel CRDI diesel engine

Abstract

ABSTRACT To maximize the performance of the diesel engine run with alternative renewable fuels, operational parameters such as injection time (IT) and injection pressure (IP) must be fine-tuned. Meanwhile, hydrogen has come out as a one of the best alternative fuel for dual-fuel mode of operation, since it minimizes the drawback that use of biodiesel alone possesses like low calorific value, high viscosity etc. Based on the above findings, the objective of the current study is set as “to evaluate the impact of varying injection parameters on the engine characteristics of hydrogen-enriched palm fueled CRDI diesel engine.” In this research work, a hydrogen-enriched (7 lpm and 10 lpm) palm biodiesel blend (P20) with diesel fuel was used to examine how changing injection pressure (IP) and injection time (IT) affected CRDI diesel engine performance, combustion, and emission characteristics. Three different IPs (240 bar, 420 bar, and 600 bar) and ITs (23°CA bTDC, 25°CA bTDC, and 27°CA bTDC) are used at a steady speed of 1500 rpm under full load circumstances. The results showed a maximum BTE of 31.09% for P20 + 10 H2 at 25°CA bTDC IT and 600 bar IP. Better fuel atomization is responsible for the improvement in BTE (17.94%) and BSFC (15.15%) with increased IP (600 bar). Advancement in IT (25°CA bTDC) leads to superior performance in terms of HC (32%) and CO (8.33%) emissions reduction for P20 + 10 H2 because more time is available for optimal air-fuel mixing. However, NOX emission increases significantly because of the rise in temperature within the cylinder with hydrogen enrichment. This can be attributed to the high calorific value of hydrogen which is almost three times to that of diesel. A maximum increase in NOX emission of 45.65% is obtained for P20 + 10 H2 w.r.t. diesel. With an increase in IP, ICP and HRR improve by 28.04% and 22.70%, respectively, due to improved fuel atomization, resulting in the greatest amount of fuel being burned during the pre-mixed combustion stage. It can be concluded that the 25°CA bTDC IT and 600 bar IP is the optimum condition when the engine performs at its peak.