Cooling systems parameters determination of tractors “Belarus” diesel engines

Abstract

Introduction. The thermal regime of a diesel engine is influenced by many factors. Some of them are taken into account during the development of the cooling system (СS), the others are set by the boundary conditions, which include the environmental temperature (+ 35°С for a moderate climate, + 45°С for tropical), the diesel load mode as the maximum operational power Ne max. The thermal state of a diesel engine with a certain combination of these factors can be violated, which leads to its overcooling or overheating, to so called unsteady thermal conditions. In this regard, there is a need to develop scientific approaches and design solutions that can contribute to the provision of a diesel engine with a given thermal regime, the improvement of the existing liquid structures and air circuits.

The purpose of the study was to optimize the cooling systems parameters of a number of “Belarus” tractors with inequality constraints and applied Kuhn–Tucker conditions, when the antigradient of the objective function under consideration is a linear combination with non-negative gradient coefficients of the active constraints.

Methodology and research methods. In the course of the study stationary points were determined with the help of Lagrange function, including the auxiliary one; the Kuhn–Tucker conditions were checked for the case when the function of two vector variables had a saddle point, and the values of extremum points were determined by a system of equations solutions.

Scientific novelty and results. The given sequence of multifactor optimization has allowed one to form and analyze various design options for cooling systems in order to identify the optimal design.

Practical significance. The numerical values of the minimum surface area of the liquid radiator and the required performance of the liquid pump are determined to ensure the given diesel engines thermal conditions of “Belarus-3522”, “Belarus-4522” tractors, etc.