Burning Water Emulsified Oil Oxygen-rich Low-temperature Combustion Test

The shortage of energy sources and environmental pollution are two serious problems that we mankind confronted with. The oxygen-enriched combustion technology in Diesel engine can not only improve the thermal efficiency and increase engine power density, but also reduce particulate emissions. It attracts the concern of academic and business community. This paper taking experiments and simulations as research method carried out research of engine performance while using oxygen-enriched combustion and diesel emulsion simultaneously, in order to provide a scientific theory basis for promotion of oxygen-enriched combustion and diesel emulsion.Taking 4100QBZL-2 type diesels as research objects, Under the rotational speed 2000rpm, For different inlet oxygen concentration (21%,22%,23%, 24%), carry on the Comparative Study of power, economy and emission characteristics and combustion characteristics when engine burning pure diesel fuel, W10, W20, W30.The measured result show that:Engine power increased slightly with the increase of inlet oxygen concentration, but the increase extend was limited. And it decreased significantly with the increase of the water concentration in fuel. In the external characteristic condition, the fuel-saving effect is obvious when used fuel was in low-water mixing ratio (less than 10%). In the equal power condition, the fuel-saving region is relatively larger. As the inlet oxygen concentration increase, particulate matter decreased, NOx increased; With the increase of the ratio of fuel mixed with water, both particulate matter and NOx emissions decreased. With the increase of inlet oxygen concentration, the maximum cylinder pressure rise, rise rate of pressure were significantly reduced. The combustion ignition delay was shortened. The heat release rate peak of pre-mixed combustion phase decreases. The heat release rate peak of diffusion combustion phase increases. The cumulative heat release increases. As the water mixing proportion of fuel increases, the phenomenon of Combustion characteristics is opposite to that of increase oxygen concentration, the max pressure cyclic variation increases. Therefore, the oxygen-enriched combustion and the concurrent use of emulsion can complement each other, and power, fuel economy and emission characteristics can be optimized better.By using the CHEMKIN chemical kinetics modeling software, the process of engine intake oxygen enrichment and water emulsion was simulated. The cylinder pressure, cylinder average temperature, the NOx formation rate and other data obtained were compared and analyzed, in order to explore a high thermal efficiency, low NOx emission control strategy, and provide theoretical guidance to develop combustion control parameter optimization. The calculation show that:during the range of inlet oxygen concentration from 21% to 24%, as the inlet oxygen concentration increases, the maximum cylinder pressure and cylinder average temperature rise, NOx formation rate peak and formation time increase; Using n-heptanes and water to simulate the water diesel emulsion, As the water mixing proportion of fuel increases, the maximum cylinder pressure and the average temperature peak is substantially reduced, the peak of NOx production rate and generation time were reduced.