Compression Ignition and Spray Combustion Characteristics of Alcohol Fuels in a DI Diesel Engine

Abstract

Entablishment of recycling energy system utilizing biomass as the storage of solar energy must be expected for the fundamental solution of global problems such as petroleum exhaustion and climate change. Final goal of this study is to realize a compression ignition and spray combustion engine system with higher efficiency and controllability using biomass-based alcohol fuels such as Methanol and Ethanol. As the first step of this research, in order to make clear the ignition and combustion characteristics of alcohol fuels, five kinds of alcohols and gas oil were tested in a small sized DI Diesel engine with glow-assisted ignition system. The test results show that difficulties of controlled ignition of alcohols are due to difficulties of mixture formation of suitable mixing ratio and attainment of required temperature of mixture for spontaneous ignition at the same time and place in a spray. Combustion rate and duration after ignition are affected with average mixing ratio of fuel sprays at the ignition timing.