Abstract
The thermal load in combustion chamber walls on diesel engine, which is a serious problem at present, is controlled by the distribution and behavior of combustion flame in the combustion chamber. In order to grasp those relations, we carried out systematically a series of experimental analyses on a 4-stroke diesel engine of cylinder bore/piston stroke = 170 mmφ/280 mm, which was equipped with a swirl chamber with a glass window for observing the combustion flame and a heat transfer plate for measuring the thermal load. The results of these tests are following. First, the strongth of air-swirl flow in the combustion chamber, the direction of fuel injection for the air-swirl flow and the direction of fuel injection for the heat transfer plate were selected, as the factors controlling the thermal load in combustion chamber walls, and the characteristics of these factors for the distribution and behavior of combustion flame were made clear. And, those characteristics for the combustibility of injection fuel and the thermal load in combustion chamber walls were grasped. Moreover, the characteristics of other factors, i. e, diameter of fuel injection hole, fuel injection timing, fuel injection rate, fuel injection quantity (air fuel ratio), engine revolution number, compression ratio and cooling condition, for the combustibility of injection fuel and the thermal load in combustion chamber walls were made clear. Accordingly, from those results, we confirmed that we were able to reduce the thermal load in combustion chamber walls by controlling the flame behavior in combustion chamber, and the general plan was grasped.
