## Determination of empirical coefficients of heat dissipation characteristics by optimization methods for a spark-ignited car engine

Mathematical Modeling, Vol. 4 (2020), Issue 1, pg(s) 35-38

For the development of new engines, as well as to obtain the correct results from mathematical modeling, numerical methods should be used, with the help of which verification of mathematical models takes place. This approach can significantly reduce the material and time costs at the development stage. The influence of the optimization method used in processing the experimental data of engine indexing to obtain semi-empirical coefficients of the form Wiebe is explored. A comparison is made of the rate of calculation of the coefficients of the Wiebe formula using brute force and gradient methods. In both methods, the integral using the modulus of the difference between squares of the experimental and calculated dependences is chosen as the target function. Analysis of the rate of calculation of the coefficients of the Wiebe formula showed the need to use the combined use of both methods: the global minimum of the objective function by the method of brute force with a large step and near the optimal point – the gradient method

• ## INFLUENCE OF INTERNAL COMBUSION CATALYST TO SHORTEN THE INGNI-TION DELAY

The paper presents a discussion of the combustion processes in the engine piston, in terms of ignition delay. The problem of the physical and chemical ignition delay is discussed and equations which allow the calculation of ignition delay based on the theory of com- bustion processes are presented. The paper proposes the use of a catalytic coating in the combustion space in order to shorten the ignition delay. The results of studies made on single diesel engine are displayed. Studies have confirmed a significant effect of the catalyst on the combustion process and shortening the ignition delay. Internal combustion catalyst used as a coating made of ZrO2 activated Pt and Rh deposited on engine valves, caused a shortening of ignition delay of about 1 – 3 degrees of crankshaft rotation.