Swirl Chamber Design Using Spray Impaction on a Glow Plug

Over the past years, many research works have been carried out to avoid wall wetting with spray impinged on chamber surfaces of diesel engines. One of the approaches to improve the problem is using spray impingement on a land prepared, in which the drops impacted are broken into a number of smaller drops and spread out much more over the combustion chamber to well mix with air. This paper addresses to the swirl chamber design using spray impaction on a glow plug. In order to evaluate impaction effects on a plug, an injection pressure, spray shapes and droplet mean diameter are taken and discussed. An injection system using the fuel feeding system of the object engine is used to get a same injection pattern, and has a solenoid valve to give injection at the request time. Firstly the characteristics of the spray impinged on the glow plug are investigated with comparison the sprays impinged or not. A new swirl chamber shape is then introduced with considering the effect of spray impaction on a glow plug. The paper continues with a consideration of spray distributions in the chamber shape. Finally the proper position of the glow plug in the chamber shape is proposed. The spray impinged on a glow plug will not move forward after impaction but spread out widely on the side of the plug. On the other hand the spray without impaction on a glow plug will impinged on a chamber wall long before beginning ignition and have wall wetting which may make a thick exhaust emissions. However in the case of impaction on a glow plug it has enough time for ignition before impinging on a chamber wall. Therefore the chamber system without spray impaction should have a narrow entrance hole to generate very strong swirl, but the other system does not need. The possibility of the spray distribution having many benefits is found with the proper position. If the spray distributed widely and mixed well with surrounding air without strong swirl motion, the energy loss in the narrow entrance hole might be reduced with increasing the hole size.