An analysis of the combustion characters and the mechanism of oil-consumption economy for diesel engines using water-blended oil

The combustion efficiency and pollutant emissions are key issues for the st udy of diesel engine combustion. The remarkable effect of water on the redu ction of pollutants has been confirmed previously, while other problems, su ch as whether oil consumption can be decreased and the overall effect of wa ter on combustion performance are still not very clear. In the present pape r, a detailed analysis for the effect of water in oil has been conducted an d the results show that: (1) compared with oil without water, the stronger entrainment ability of water-blended oil, leading to more complete combusti on and more rapid heat release, is one of the main reasons for decreasing o il consumption; (2) because of the production of steam from water in oil, t he pressure in chamber will be increased and the engine power output may be improved, which will partly overcome the disadvantages of heat absorption by water vaporization and contribute to oil consumption economy; (3) althou gh more latent heat of water vapor may be lost in the exhaust with the incr ease of the amount of water in oil, the temperature in the chamber will be depressed also and the total enthalpy loss is less, again decreasing oil co nsumption. Furthermore, there is an optimal water content to lead to a maxi mal power output. (C) 2001 Elsevier Science B.V. All rights reserved.