Diesel engine operation on alcohol fuels using a computer controlled fumigation process

摘要

Alcohol fuels have been shown to be very attractive alternative fuels for automotive use. They are considered to be cleaner fuels for protection of the environment and they are good alternatives to petrol because of higher octane numbers. Use of alcohol fuels in compression ignition engines has also attracted worldwide interest due mainly to its ability to burn without producing particulate emissions. This study shows that an inexpensive conversion system developed on a small single cylinder research engine enables a diesel engine to operate on near 100 percent methanol or ethanol. A computer control system has been built to exploit the possibility of on board vehicle application in the future. A fumigation method was adopted for this work, which involved adding a carburettor to the inlet manifold to fumigate the inlet air with alcohol fuel. This mixture formed an ignition centre for the main body of alcohol fuel injected into the cylinder in a conventional manner. A computer acquisition system enabled the fumigated mixture to be controlled at a suitable percentage of alcohol and inlet temperature, which helped the evaporation of induced alcohol, to produce the optimal engine performance under the specific speed and load conditions. Test results showed the satisfactory combustion over the range of engine operating conditions. This method has the potential of allowing diesel engines to operate on virtually 100% alcohol without considerable change to the engine and hopefully to the road use after further investigations.