Effect of Fuel Injection Timing on the Emissions of a Direct-Injection (DI) Diesel Engine Fueled with Canola Oil Methyl Ester-Diesel Fuel Blends

摘要

Biodiesel is the name of a clean burning monoalkyl-ester-based oxygenated fuel made from natural, renewable sources, such as new/used vegetable oils and animal fats. The injection timing plays an important role in determining engine performance, especially pollutant emissions. In this study, the effects of fuel injection timing on the exhaust emission characteristics of a single-cylinder, direct-injection diesel engine were investigated when it was fueled with canola oil methyl ester-diesel fuel blends. The results showed that the brake-specific fuel consumption and carbon dioxide and nitrogen oxide emissions increased and smoke opacity, hydrocarbon, and carbon monoxide emissions decreased because of the fuel properties and combustion characteristics of canola oil methyl ester. The effect of injection timing on the exhaust emissions of the engine exhibited the similar trends for diesel fuel and canola oil methyl ester-diesel blends. When the results are compared to those of original (ORG) injection timing, at the retarded injection timings, the emissions of nitrogen oxide and carbon dioxide increased and the smoke opacity and the emissions of hydrocarbon and carbon monoxide decreased for all test conditions. On the other hand, with the advanced injection timings, the smoke opacity and the emissions of hydrocarbon and carbon monoxide diminished and the emissions of nitrogen oxide and carbon dioxide boosted for all test conditions. In terms of brake-specific fuel consumption, the best results were obtained from ORG injection timing in all fuel blends.