The Influence of Exhaust Gases Dissolved in Diesel Oil on Fuel Spray Particulary Parameters 2007-01-0488
The Institute of Combustion Engines and Transport has developed a concept of fuelling diesel engines with an improved mechanism of spray. To facilitate the spray, and consequently the combustion process, air or exhaust gas was dissolved in diesel oil. The gases mixed with diesel oil formed a solution, which induced non-equilibrium state owing to its effervescence. As a result, the gaseous phase spontaneously released from the solution throughout the whole volume.
The paper presents the results of observations and measurements of the fuel injection into the open chamber recorded with AVL 513D Engine Video System. The injection process has been realized with a common rail system, where the conventional mechanism of fuel atomization has been enhanced by the presence of gas in the fuel. The solution of gas and fuel was considered separately as non-saturated, saturated and supersaturated (in the last case, some amount of gas remained undissolved in the fuel). The gas used in the solution was exhaust gas due to its coefficient of solubility which is two orders of magnitude higher than that of air. It was observed that the fuel atomization mechanism was significantly influenced by the presence of gas in fuel, what was confirmed by the changes of: the shape of the flow, the initial velocity of gas outflow in injector holes, the range and cone angle of the flow. Additionally, some qualitative changes in the structure of the fuel spray were noticed, too. In comparison to the conventional injection, more fuel droplets with smaller diameter were observed as well as better homogeneity of fuel mass distribution along the cross-section of the flow.
At the moment, widespread research is conducted in order to evaluate the benefits of practical application of the concept in the injection system.