Dual fuelling CI engine with methanol and diesel oil

Dual fuel compression ignition engine can be run on diverse fuels, both gaseous and liquid ones. Alternative fuels to the Diesel oil feature, as a rule, low cetane number and high temperature of self-ignition. Due to this, such fuels can not be ignited spontaneously and require ignition from small dose of the Diesel oil. In the dual fuel system, as the main fuel can be considered a liquid fuels, which can be supplied to the cylinder in form of vapours, or injected be to the suction manifold. Methyl and ethyl alcohols, or their esters, can be counted among future fuels. Such alcohols can be either the main fuels or small additions improving combustion of the Diesel oil. In the paper are presented test results of the SW 680 engine run on methanol and Diesel oil. Methanol was supplied to the suction manifold in form of methanol-air aerosol. Energetic fraction of the methanol amounted to 12-50%, depending on engine load. Performed tests have shown advantageous effect of the methanol on performance of the engine. One confirmed considerable growth of overall efficiency of the engine in area of higher loads (3-6%), reduction of smokiness of exhaust gases achieved as early as with small additives of the methanol (2-3 times), reduction of CO and CO2 emissions, reduction of exhaust gases temperature. Small addition of the methanol affects advantageously on combustion of the Diesel oil, shortening time if its combustion. Addition of the methanol enables maintaining effective power of the engine fuelled traditionally, and even its slight growth. Cost of adaptation to dual fuel supply with alcohol are low, and such type of fuelling can be easy implemented in already operated compression ignition engines.