An Evaluation of the Effect of Fuel Injection on the Performance and Emission Characteristics of a Diesel Engine Fueled with Plastic-Oil–Hydrogen–Diesel Blends

Fuelled engines serve as prime movers in low-, medium-, and heavy-duty applications with high thermal diesel efficiency and good fuel economy compared to their counterpart, spark ignition engines. In recent years, diesel engines have undergone a multitude of developments, however, diesel engines release high levels of NOx, smoke, carbon monoxide [CO], and hydrocarbon [HC] emissions. Due to the exponential growth in fleet population, there is a severe burden caused by petroleum-derived fuels. To tackle both fuel and pollution issues, the research community has developed strategies to use economically viable alternative fuels. The present experimental investigations deal with the use of blends of biodiesel prepared from waste plastic oil [P] and petro-diesel [D], and, to improve its performance, hydrogen [H] is added in small amounts. Further, advanced injection timings have been adopted [17.5° to 25.5° b TDC (before top dead centre)] to study their effect on harmful emissions. Hydrogen energy shares vary from 5 to 15%, maintaining a biodiesel proportion of 20%, and the remaining is petro-diesel. Thus, the adopted blends are DP20 ((diesel fuel (80%) and waste plastic biofuel (20%)), DP20H5 (DP20 (95%) and hydrogen (5%)), DP20H10 (DP20 (90%) and hydrogen (10%)), and DP20H15 (DP20 (85%) and hydrogen (15%)). The experiments were conducted at constant speeds with a rated injection pressure of 220 bar and a rated compression ratio of 18. The increase in the share of hydrogen led to a considerable improvement in the performance. Under full load conditions, with advanced injection timings, the brake-specific fuel consumption had significantly decreased and NOx emissions increased.