Maximum automobile acceleration

Abstract

Problem. The disadvantage of current dependences for determining the acceleration indicators at engine maximum brake power and driving tire-to-surface friction coefficients is that they are adequate only if the engine and transmission parameters provide power input to the drive wheels rolling without slipping regardless to speed. To eliminate this drawback, it is necessary to take into account that the power input to the drive wheels depends on the engine shaft speed, and therefore on the speed of the vehicle when accelerating. Goal. The purpose of the work is to further develop the theory of the automobile by improving the dependencies that allow determining the automobile acceleration rates and assessing the nature of its acceleration process from the design factors. Methodology. The approaches taken to achieve this goal are based on laws of physics, theoretical mechanics and the theory of automobile. Results. Analytic dependences for determining maximum and limiting automobile acceleration when speeding up depending on its design factors and speed have been improved. Dependences for determining the range of drive wheel slipping on the automobile speed when accelerating and the limiting automobile acceleration under the condition of its pitch stability have been obtained. When studying the automobile acceleration process theoretically it was found that the developed dependences allow determining the nature of automobile movement and assessing the influence of its design factors on the acceleration indicators. Originality. The obtained dependences for determining the maximum and limiting acceleration, the range of driving speeds with wheel slip when automobile accelerating allowed us to clarify the idea of the nature of movement during acceleration and the influence of automobile design factors on the acceleration indicators. Practical value. The obtained dependences can be used in designing new and improving racing cars such as dragsters, and analysing the dynamics of the vehicle when accelerating with full fuel delivery and determining the nature of driving tire-to-surface friction depending on the driving speed.

Determining the possibility of slipping the driving wheels of the car

“…Further increase in the speed of the car occurs without slip. The obtained data coincide with the results provided in works [5,12]. In Figure 6, the points of intersection of the dependences of the acceleration of the car j a and the maximum possible acceleration under the conditions of the clutch j ϕ on the speed of motion correspond to the values of the interval determined by condition (17).…”

“…In the scientific work [7], the author provides a balance of forces acting on the car during acceleration, considering the energy losses due to the angular acceleration of the rotating masses, but does not determine the possibility of the drive wheel slip. The dependence of the acceleration of the car on the speed of motion with slip of the driving wheels was obtained in works [5,12].…”

“…Theoretical studies of car driving modes have been conducted to compare the results of determining the speeds at which the drive wheels can slip with the results provided in works [5,12].…”