IMPROVEMENT OF THE METHOD OF EXPERIMENTAL-THEORETICAL DEFINITION OF PARAMETERS OF AERODYNAMIC MOTOR VEHICLE SUPPORT

Aerodynamic motion resistance is a factor that has the greatest impact on the energy dissipation of the car engine. Traditionally, aerodynamic resistance parameters were determined by blasting the car in an aerodynamic tube. This allowed the most accurate determination of the coefficient of frontal aerodynamic resistance of the vehicle at a given blowing speed. The development of methods and means for determining the kinematic parameters of the car while driving allowed the development of a number of techniques that allow them to determine the parameters when riding a car. In this paper, with the study of the method of partial accelerations, an advanced method for determining the parameters of the aerodynamic resistance of the vehicle is proposed. The analysis of recent studies and publications has shown that the current methodology for calculating the aerodynamic resistance of a car is proposed at the beginning of the last century in known works and has not been changed over the course of the century. This technique is not effective at low speeds to determine the aerodynamic resistance of vehicles and is designed to determine the coefficient at high speeds, since the coefficient C x depends on the shape of the body. Therefore, considering C x independent of velocity, the results of theoretical and practical studies show that the expression for the calculations is not valid over the entire velocity range. At low speeds (up to 1 m / s) the law of the first degree of speed is valid; at higher speeds close to the speed of sound, the law of cubes takes place; at speeds higher than the speed of the sound again the square-cube law is again observed. In the considered work it is noted that taking the square-cubes law in all the cases, it is necessary to set the coefficient C x depending on speed V a . In this article, using the method of partial acceleration, an advanced method of determining the parameters of aerodynamic resistance of a car is proposed. In this article, the method of calculating the aerodynamic resistance of the vehicle is improved. The theoretical basis and algorithm of determination of parameters of aerodynamic resistance of a car using the method of partial accelerations are developed. A more thorough method of determination of parameters of aerodynamic resistance is offered, which allows carrying out an estimation of energy-transforming properties of automobiles.