Method of calculating the influence of the suppression system on the autonomy of an armored combat vehicle

Abstract

A method of calculating the effect of vibrations of the sprung body and the operation of the suspension system of an armored combat vehicle on its autonomy has been developed. One of the main indicators of autonomy is the power reserve, which depends on the specific fuel consumption. In the process of moving over bumps, a significant part of the power plant's energy, and accordingly fuel, is spent on the occurrence of vibrations of the sprung body of the machine and its unsprung masses. Then the energy of these vibrations is converted into heat in the damping devices of the chassis. In difficult road conditions, on real tracks, these losses average 10...15% of power plant power. In resonant modes, when moving along a harmonic profile of irregularities, they can reach 30%. Calculation and reduction of these costs will increase the autonomy of the armored combat vehicle.
 The methodology is based on the calculation of the energy balance of the longitudinal, angular and vertical vibrations of the sprung body of the machine and the vibrations of its unsprung masses, the deformation energies of the elastic elements of the suspension, the rubber hinges of the guide devices and tires, as well as the energies absorbed by the suspension damping devices, its rubber hinges and tires. Depending on this balance, there is either an increase in the load on the power plant and, accordingly, an increase in fuel consumption, or it decreases and the energy of the suspension system becomes the driving force. To calculate the oscillations of the sprung body and components of the energy balance, it is necessary to use a mathematical model of the movement of an armored combat vehicle over bumps. All the necessary parameters of the machine, a deterministic road profile of bumps and a high-speed driving mode are set. Amplitudes and velocities of longitudinal angular and vertical oscillations of the sprung body and oscillations of unsprung masses are calculated from these input data. For each suspension, its kinematics, twisting angles of torsions, forces in damping devices and the amount of movement of their working bodies and deformation of rubber joints and tires are calculated. Next, the magnitude and sign of the change in the total energy of the sprung body and the sprung system at each moment of time is determined. Based on the additional energy calculated using the efficiency coefficients of the engine and transmission, the additional power supplied by the power plant and, accordingly, additional fuel consumption are determined.
 Thus, it is possible to evaluate and compare with each other the reduction in the range of the armored combat vehicle, which is caused by the fluctuations of the sprung body and the operation of the suspension system, depending on the type and characteristics of the suspension, when driving in specific road conditions, at the given speed modes. With the help of the developed methodology, it is possible to carry out structural and parametric optimization of the suspension kinematics and the characteristics of its elastic elements and damping devices, in order to reduce fuel consumption and increase the autonomy of the armored combat vehicle. This technique will be useful in assessing the expediency of using the energy recovery system of the suspension system, depending on the purpose and conditions of operation of combat armored vehicles.