Dissolving Gas in Diesel Fuel as a Way for Fuel Oxygenation and Diesel Exhaust Emissions Reduction

摘要

The paper describes the research on the problem of oxygenating diesel fuel with the use of gases containing oxygen (air or diesel exhaust gas). The incentive, which encouraged the authors to exploit this idea, was a number of promising results of some earlier research on oxygenated fuel additives. The paper provides a detailed description of the system, especially the injection pump for dissolving gas in the fuel, designed and built by the authors. The paper describes also some changes in physical and chemical parameters of the fuel, which were observed while the fuel was flowing through the experimental injection system. These changes resulted from the reactions between fuel and oxygen, which were additionally reinforced by high pressure and temperature in the experimental injection system. In the further part of the article, the attention is drawn to the way the gases containing oxygen influence the exhaust emissions. The direction of the change is comparable to the one observed during the application of diesel fuel containing oxygenated additives. In both cases the fuel modifications allow lowering the emissions of the incomplete combustion products, but simultaneously, they boost NO{sub}x emissions. However, if the experimental system is used the emissions change not only owing to an increased amount of oxygen in the fuel, but also owing to improved fuel spraying, which consists in dissolving gas in the fuel and then releasing it during fuel injection and combustion. According to the authors, the analysis and tests carried out so far have confirmed the practicality and applicability of the fuel injection system facilitated with gas dissolved in the fuel. Though the system still requires further development and optimization, and despite some constructive as well as exploitative problems that must be overcome, it appears to be an interesting alternative to high-pressure injection systems.