Performance and Emission Characteristics of Heptane/Toluene Blends at Constant Injection Operation on a CI Engine

Abstract

Hydrocarbons are chemical compounds whose molecules are made of hydrogen and carbon. Heptane is an aliphatic hydrocarbon with good ignition quality and high cetane number, while Toluene is an aromatic hydrocarbon with a very poor ignition quality and very low cetane number. The two different compounds are blended in varying proportion and tested in a single cylinder 2.0L Ford Puma automotive diesel engine to investigate their effect on engine performance and emission. The cylinder pressure, heat release rate, exhaust gas emissions and particulate were measured. The results show that H70T30 blend has the highest specific NOX emission which was due to the high peak temperature and produces slightly more soot than pure heptane (H100T0). H50T50 attained the lowest heat release rate, peak cylinder pressure and temperature. These low values favour the formation of low NOx, high amount of unburned hydrocarbon and high amount of soot particles. Although heptane has a high cetane number, it fails to act as an ignition improver to toluene.