Effect of pilot and post fueling on the combustion and emission characteristics of a light-duty diesel engine powered with diesel and waste cooking biodiesel blend

Biodiesel produced from waste resources provides both environmental and economic benefits. The use of biodiesel blends in tandem with advanced fuel injection strategies enables effective control over engine-out emissions. The current study investigates the effect of the pilot and post fuel injection on combustion and emission characteristics of a light-duty diesel engine fueled with standard diesel and waste cooking biodiesel blend. The engine adopted for this study is an automotive common rail direct injection (CRDI) diesel engine, wherein the electronically controlled fuel injection system provides flexibility to control single and multiple injection schedules along with the provision for change in fuel injection pressure. A blend of 80% diesel and 20% waste cooking biodiesel (B20) was tested at four-part loads and three fuel injection pressures. The test results indicated a considerable reduction in smoke (84.4%), hydrocarbon (71.8%), and carbon monoxide (46.8%), compared to the base diesel (D100) operating at a single injection and lower fuel injection pressure. Also, Brake thermal efficiency was improved by 4.46%. However, nitric oxide emission was found to be 15% higher due to the higher fuel injection pressure. The experimental results affirm that the usage of pilot and post-injection along with higher fuel injection pressure for waste cooking biodiesel blend yielded a significant reduction in emissions at part-load condition.