Effect of Engine Operation Parameters, Fuel Property and Exhaust Gas Treatment on Exhaust Odour in Direct Injection Diesel Engines

Abstract

This study investigated the effect of engine parameters: injection timing, exhaust gas re-circulation (EGR), engine speed, injection pressure, compression ratio, and others; alternate fuels n-heptane, n-decane and methyl tertiary butyl ether (MTBE); and exhaust gas treatment by catalytic converters, water-washing and air-dilution systems on exhaust odour in direct injection (DI) diesel engines. Engine parameters, injection timing and injection pressure are found most promising for the effective control of odourous emissions. To test the effect of fuel properties on odour, n-heptane, a low boiling point fuel, n-decane a fuel with high cetane number and an oxygenated fuel MTBE are investigated. The fuel n-decane shows a great prospect to reduce exhaust odour. In exhaust gas treatment, a catalytic converter is attempted first. The catalytic converter is very promising in reducing exhaust odour when the engine exhaust temperature is 200 °C or more. This happens when the engine is under load. But at the idling condition of the engine, the exhaust gas temperature is much below of 200 °C (hardly 100–120 °C). In this condition, the use of catalytic converters is ineffective. Here new ideas of water-washing and air-dilution of exhaust gases have been introduced. The water-washing and air-dilution systems are found very effective to reduce odour at the idling condition of the engine.