Diesel Exhaust Clarification by a High-Pressure Injection in Combination with Selective Exhaust Gas Recirculation

点击翻译按钮获取中文摘要

This study dealt with a novel diesel engine system that uses high-pressure injection and selective exhaust gas recirculation, with an objective of finding out the possibility of a significant reduction of particulate matter and oxides of nitrogen from diesel engines. A High-pressure injection offers an effective means to reduce particulates. For this reason, a fully electronic controlled high-pressure injection system was first developed. The system uses hydraulic spool acceleration and oil-hammering in a convergent pipeline. The characteristics of this injection system were investigated in detail. Tests were made using the injection system at a direct-injection diesel engine with optimal nozzle-orifice determined by theoretical study. The result shows that particulate matter at a higher load and oxides of nitrogen at middle load are reduced successfully on account of the fact that the injection pressure increases with the engine load. According to observations of diesel flame by high- … More speed photography, fluctuations of flame luminosity is reduced at high-pressure injection.A further reduction of oxides of nitrogen is intended to use selective exhaust gas recirculation using triatomic gases of carbon dioxide and water both being extracted from the exhaust. These triatomic gases have higher heat capacity and as a result combustion temperature is well reduced enough to suppress nitric oxides. To establish the selective water recirculation, system, effects of the introduction of water or moisture in intake air on reduction of oxides of nitrogen were first investigated experimentally. Based on the results, prediction were made for the effect of recirculation of water that is condensed from exhaust gas for various engine loads. It was found that a remarkable reduction of nitric oxide is obtainable at higher loads, because of greater extraction of water from exhaust. Furthermore, the recirculation system of carbon dioxide in exhaust gas was designed. The system employed monoethanohl-amine solvent as chemical absorbance. A prototype system of selective recirculation combined with high-pressure injection system is established successfully. Less