Abstract
This paper investigates engine performance and emission characteristics with water-emulsified fuel including vegetable oil. The experiments used equal proportions of used frying oil and gas oil, biodiesel fuel from used frying oil, and equal proportions of rapeseed oil and gas oil as the base fuel. Performance tests of two types of single cylinder DI diesel engines showed that the NOx concentration and smoke density both reduced without worsening BSEC (brake specific energy consumption) with water to fuel volume ratios of 15 to 30% at a rated output. The paper also investigates evaporation and combustion characteristics of the water emulsions with basic experiments of suspended droplet combustion. Compared with water free fuels, the ignition lag of emulsified fuel droplets was longer while the combustion duration shortened with micro-explosion or puffing occurrence.
