Effect of oxygenated fuels on emissions characteristics: a comparative study between compression ignition and spark ignition engines

Abstract

It is agreed by scientists world-wide that continued burning of petroleum oils without intervention is a great threat to the environment. In this study a comparison is made of the extent of emissions produced between diesel and gasoline engines using oxygenated blends. In the gasoline engine 20% methanol -80%, gasoline M20 was used. In the diesel engine, 20% n-butanol and 80% diesel B20 was the test fuel. The gasoline engine was a naturally aspirated Suzuki RS-416 1.6L engine type and the diesel type engine was a 1Z type, 1.9L Turbo-Direct injection (TDI). The results obtained were as follows: the NOx emissions increased with an increasing BMEP for Diesel Fuel (DF) but was slightly lower than the blend B20 at 50 and 75 % load; whereas using M20, Nox reduced in reference to gasoline fuel (GF) but was four times higher than that obtained in diesel engine; using B20 diminished the quality of Unburned hydrocarbons (uHc) emissions in diesel engine based on the reference fuel DF. The range of emissions of uHC however was far less in the diesel engine than in the gasoline engine.10-60 ppm and 600 to 700 ppm respectively. The blend M20 reduces uHc more than the GF above 25% brake mean effective pressure (bmep).The formation of Carbon monoxide (CO) was rapid for M20 than GF; emission concentration of CO in B20 increased above DF. Exhaust gases temperature (EGT) was lower for all oxygenated blends, M20 and B20, than neat or pure hydrocarbon (HC) fuels: GF and DF.