A comparative study of particulate and gaseous emissions, of a diesel engine fuelled conventionally and with dimethyl ether.

摘要

A comparative study of the particulate and gaseous emissions of a 2 cylinder Lister-udPetter compression ignition engine when fuelled with diesel and dimethyl ether wasudundertaken. The investigation involved the commissioning of a Cambustion DMS500udFast particulate Spectrometer, allowing the spectral densities and cumulativeudconcentrations of particulates in the exhaust stream to be sampled. The investigationudwas performed for changing engine speeds at various engine loads, namely:ud1300rpm to 1800rpm at 25Nm to 45Nm. Along with particulates, THC, NOx, CO2 andudCO were measured using various Signal Gas Analysers. Various engineudperformance measures were also recorded, including maximum cylinder pressureudand temperature, air/fuel ratio, exhaust temperature, shaft speed, torque and fueludconversion efficiency. The most notable finding was that particulate sizes were in theudrange of 150nm to 170nm under diesel fuelling whereas for dimethyl ether fuellingudthey were 5,5nm to 7nm. It was also found that increasing engine speed withuddimethyl ether fuelling causes an increase in the particulate size, whereas with dieseludfuelling increasing engine load resulted in an increase in size. The concentration ofudparticulates was seen to increase with increasing engine speed. It was also foundudthat under both fuelling methods there exists an indirectly proportional relationshipudbetween NOx and particulates.