An experimental study on the effects of oxygenated fuel blends and multiple injection strategies on DI diesel engine emissions

Experimental studies on effects of oxygenated fuels in conjunction with single and split fuel injections were conducted at high and low loads on a Caterpillar SCOTE DI diesel engine. At high loads, a significant beneficial effect of oxygenated fuels was seen to reduce soot emissions with little or no penalty on NO, emissions. Also, at high loads, split injection had an additional favorable effect on soot emissions as compared to single injections, but the soot reducing influence of the oxygenates was not as marked as that seen with the single injection cases. This result indicates that the soot reduction due to the addition of oxygenate to the fuel is most effective in rich combustion as split injections are known to be effective at leaning-out the charge. In fact, at low engine loads when the overall mixture is further leaned-out, the oxygenated fuels had only a slight effect on particulate emissions. Split injections were effective in reducing particulate emissions at low loads particularly at advanced fuel injection timings when overall temperatures would be expected to be higher. (C) 1999 Elsevier Science Ltd. All rights reserved.