Study On Exhaust Emission From A Diesel Engine Fueled With DME

The research on DME as alternative fuel to diesel engine has risen in the world, but at present the engine performance and regular emissions are preferred to. Some studies investigate the combustion mechanism of DME, but a few is involved in the trace emissions such as formaldehyde, formic acid and formic ether, and none goes into their formation mechanism. For better emission control of diesel engine, this paper will find out an appropriate sampling system not only for regular emissions but also for the trace emissions from the existing sampling systems, and apply it on the emission test. After optimization of operating conditions on the trace emissions measurement by gas chromatography, calibration of FID by external standard method, we can find out the emission performance of diesel engine fueled with DME. The experimental results show that the FID is too insensitve to formic acid, and can't meet with the requirements of measuring formic acid. Much higher formaldehyde emission than usual is observed, and at some working conditions a small amount of formic ether can be detected. Six factors'(speed, load etc.) orthogonal test is designed to find out the regular and trace emission trend. Statistic analysis is done by advantage of the orthogonal table, and from which the dominant factor and optimized conditions are worked out. The advantage of orthogonal test is that the same result to ordinary experiment can be achieved with less work.