Injection Of Methanol At Low Pressure In D.I. Dual-Fuel Engines

This paper describes an experimental investigation of direct injection of Methanol at low pressures in a dual fuel engine. The main purpose of the investigation was to find the maximum possible substitution of diesel oil by methanol, the engine efficiencies and emissions. The timing and rate of injection of the diesel oil and of the methanol were varied systematically. Strategies for load control of the dual fuel engine and effects of increased intake pressure and temperature were also investigated.

Methanol was injected into the combustion chamber of a single cylinder experimental D.I. engine through an electronically governed nozzle at pressures ranging from 5 to 8 bars. Referring to lower calorific values, 77 per cent of the diesel oil could be substituted by methanol at 20 °C in-take air temperature. At 53 °C intake air temperature, maximum substitution was as high as 85 per cent. Shaft power was increased by 36 per cent, when changing the engine from conventional diesel to the dual-fuel concept. Engine efficiency was improved by 14 per cent (from 0.29 to 0.33) at full load.