Experimental Study on the Performance and Emission Characteristics of a Diesel Engine on an Actual Ship Using Diesel Fuel and Water-Diesel Emulsion

This paper experimentally investigates the effects of water-diesel emulsion properties on marine diesel engine performance and exhaust emissions. The study was conducted in a six-cylinder, in-line, four-stroke, direct-injection 3D6 marine diesel engine that runs on water-diesel emulsion and pure diesel fuel according to the propeller characteristic. The results show that the chemical energy of the gas mixture in the cylinders of an engine using the water-diesel emulsion of 15% water content was 0.875 times that of diesel fuel. The emulsion consumption must be increased by 1.14 times to compensate for the loss of chemical energy, and the excess air coefficient is more significant by 1.225 times. A part of the heat released from the reactions is spent on water evaporation during emulsion combustion, which reduces the exhaust gas temperature and NO_x by more than 35%. On average, the smoke number is higher by 2% in low-speed modes, while it is less than 3% in other operating modes. The reduced percentage of specific NO_x and CO emissions was varied by 6-43% and 45-65%, respectively.