SCIENCE & EDUCATION

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The article conducts a reasoning analysis for using a gearbox in electric motor vehicles, in particular in vehicles with hybrid powertrain. It presents external high-speed characteristics of internal combustion (IC) engines in vehicles with hybrid powertrain engines and electric motors that can be set in vehicles with hybrid powertrain, which are used to compare characteristics of horsepower balance and accelerations of these vehicles both with IC engine and gearbox and with electric motor. To prove the need of a gearbox application, both in the electric vehicle, and in the in vehicle with hybrid powertrain, comparative diagrams of accelerations and power balance of the vehicle with electric motor without a gearbox and with electric motor in combination with the 2-, 3-, 4-staged gearboxes are provided.

Nowadays, good distribution of electric vehicles and hybrid electric ones is reached. The article describes the prospects of development of medium cargo urban vehicles with hybrid powertrains using components manufactured in Russia. It also describes the advantages and disadvantages of the chosen scheme of powertrain. This requires good analysis and depends on type of the vehicle and key component features. The need to apply the test benches for experimental studies is justified. Also the aim of this article is to study a reasonability of key components manufactured in Russia. The authors describe the construction of an experimental vehicle with a hybrid powertrain. They also developed an algorithm of the vehicle operation with a hybrid powertrain during its movement in the urban cycle, which takes in the drive into account a power balance.

A developed universal mathematical model to accelerate a tractor unit (TU) at gear shifting in the gearbox (GB) with different overlaps and at TU acceleration from rest, for different options of friction clutches (FC) installation on the shafts in the GB allows defining - at the designing stage of GB with FC - their work and slipping time and the acceleration time of a TU which may lead to designing the reliable friction clutches and gearboxes with friction clutches. The proposed calculation method of the work of the friction clutch slipping in the gearbox at bench tests allows transferring test results into the operation loading mode, and, therefore, to perform fine-tuning of gearboxes with friction clutches at bench tests.

The paper proposes a model to form the torque on the working body of the deep milling machine in the interaction with the soil and with the forest-bush vegetation growing on the surface, its root system. The load is presented as a sequence of pulses with random parameters and complex structure. The developed approach enables us to determine the spectral density of the loading moment on the milling cutter taking into account the operation conditions, its structure, physical and mechanical properties of soils, and probabilistic characteristics of random operation conditions at the design stage. Probabilistic characteristics of the moment on a cutter are initial information for the analysis of dynamic loads in the drive elements of deep milling machine at the design stage.

The article substantiates an urgency to develop the theoretically grounded techniques for the bench tests of automotive engineering. It introduces a new principle to simulate the load operating conditions with moving wheeled vehicle in outdoor environment at the bench «Roller. A mathematical model of wheeled vehicle dynamics both at the bench and on the road has been developed. The mathematical simulation allows us to conduct the theoretical researches of straight-line dynamics of a single wheel on the hard non-deformable support base with different characteristics. The results of mathematical simulation proved the efficiency of the proposed approach and the created mathematical model. Further research trends based on this principle are justified.

The paper presents the created finite element models of car seats with passive head restraints of three levels of complexity, conducts their analysis in terms of the simulation error assessment and meeting the UNECE Regulations No 25. It discusses the basic principles for designing the finite element models of head restraints and car seats with different complexity. These models are assessed in terms of result errors and effort to develop and find solution, using software packages (ANSYS, Femap and LS-DYNA) that implement the finite element method. Performed calculations based on the finite element method give a possibility to analyze a large data file about the process of emergency loading, which is required to estimate the safety of car seats in the case of the rear-end impact to car.