The Influence of CNG Dissolved in The Diesel Fuel on the Combustion Process and Concentration of Toxic Compounds in Exhaust Gas 2008-01-1815

The Institute of Combustion Engines and Transport has developed a concept of fuelling diesel engines with an improved mechanism of spray. The proposed novelty value of spray consists in dissolving either air, exhaust gases or CNG in diesel fuel.

The effervescence of diesel fuel mixed with gases is to facilitate the spray. In the non-equilibrium states of a solution, formed as a result of dissolving gas in a liquid, the gaseous phase is spontaneously released from the solution. This process has a volumetric character and at the appropriate kinetics it is strong enough to be accompanied by the effervescence (bubbling) of the liquid. At the moment, widespread researches are carried out in order to evaluate the practical application of the concept in injection systems. The article presents the results of tests concerning the impact of CNG dissolved in diesel fuel on the combustion process in diesel engines. The tests were done in the piston head of an engine equipped with a toroidal combustion chamber and direct injection. During the tests the following factors were measured: the main indicators of motor operation, the range of pressure values obtained in the combustion chamber and before the injector, emissions of HC, CO₂, CO, NO_x and FSN.

Furthermore, the article shows the images of fuel injection into the open chamber recorded with AVL 513D video system. The diesel fuel-based fuelling system was compared with the solution-based fuelling system in terms of the heat release.