One of the various efforts to reduce PM and NO emissions from modern diesel engines is the use of light fuels fumigation as supplement to pilot injected diesel fuel. Present work aims at developing a fumigation system for introduction of gasoline in a diesel engine with mechanically-controlled fuel injection pump and to determine its effects on emission. Experiments were performed on a 4-cylinder direct-injection diesel engine operating at two constant engine speeds for different engine loads. Diesel fuel was considered as baseline fuel and gasoline was inducted as fumigation in intake manifold at two different ratio on every operation modes. The experimental results show that with gasoline fumigation, the specific NOx and CO2 emission decreased to about 28, and 7% (averaged on all engine loads), respectively in comparison with baseline diesel case. While smoke opacity decreases at high loads up to 50%. However, increase in the specific CO and HC emission have been found after use of premixed gasoline at all loading conditions. Moreover, gasoline fumigation can improve brake thermal efficiency slightly at intermediate and high loads. Thus, gasoline fuel as premixed fuel with fumigation method showed a favorable potential in terms of reduction of main emissions and improvement performance in diesel engines with mechanically-controlled fuel injection pump.

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