On the Influence of the Shape of the Combustion Chamber of a Diesel Engine on Its Efficient Indicators

Purpose. Increasing the effective performance of the diesel engine due to the improvement of the course of thermal processes in the combustion chamber, in particular, reducing the time of formation of the working mixture. Research methods. The physic-mathematical model for calculating the working cycle of the second level of internal combustion engine in the second modification – as the basis of a computational experiment, as well as the planning of a multifactorial experiment based on models of the first and second orders. Computational calculations according to the given model were carried out using the Engine Calculation program, which implements the modified Euler method. Results. The influence of the shape of the combustion chambers of a diesel engine on its effective performance was studied. It is shown that manipulations with the very shape of the piston (changing its bottom) have a direct effect on the processes of mixture formation and combustion, which affects more global indicators of engine performance, such as economy and power. A plan of experimental research was built, on the basis of which, as a result of the thermal calculation, the dependences of the engine’s effective indicators on the studied parameters were obtained. Scientific novelty. For the first time, on the basis of a multifactorial experiment, the influence of such factors as the relative heat exchange area of the piston and the indicator of the nature of combustion on the effective performance indicators of a diesel engine was analyzed with the interaction effect. It has been proven that the ratio Fp'/Fp = 1.3 with the value of the combustion characteristic index m1 = 0.4 is optimal for ensuring effective performance of a diesel engine. Practical value. The proposed modernization of the shape of the combustion chamber of the existing engine, which makes it possible to increase its indicator efficiency while reducing the specific indicator fuel consumption, can be applied to diesel engines of a similar class.