Introduction. The development of environmentally friendly vehicles is associated with the introduction of high-voltage sources and power converters in their design. Sources of electricity are represented by energy storage and storage systems, which under various environmental conditions can have different undesirable efficiency.

The purpose of the study was to determine the problems similarly affecting high-voltage systems operability and storing electricity during operation in regions such as the Russian Federation and the Socialist Republic of Vietnam.

Methodology and research methods. Analytical studies conducted by the authors permitted them to point out the pressing problems of electric vehicles and cars with combined power units, as well as to identify promising ways to solve these problems.

Results. The relevance of the study was to consider the similar problems of the electric vehicles introduction and operation in the Russian Federation and the Socialist Republic of Vietnam. Despite the diametrically opposite climatic features of Vietnam and Russia, the problem of temperature stabilization of the battery of an electric vehicle was similar by nature and required a comprehensive solution. The existing experience was studied and the negative aspects that impeded the development of environmentally friendly vehicles in the private sector were shown.

Practical significance. Deficiencies in the development of electric vehicles in the future were identified. The question of the electric vehicles operation and their performance in the difficult conditions of both Russian Federation and Vietnam was raised. This systematization will allow to create the unified algorithms and schemes of systems permitting to work both in hot and in cold climates.

Introduction. It is known that the traction and coupling properties and the cross-country ability of multi-purpose wheeled vehicles (MPWV) on soil surfaces depend both on the mover parameters of these machines and on physicomechanical properties of the movement surfaces. The article discusses the optimization of these machines propulsors parameters, depending on road conditions and physicomechanical properties of the soil surface.

The purpose of the study was to develop recommendations for optimizing the propulsion parameters of promising MPWV designed for operation and movement on soil surfaces.

Methodology and research methods. The research methodology was based on the results of the analysis of modern studies on soil mechanics being under the effect of a dynamic load and was to formulate a complex of dependencies that determined the interaction process of driven and driving wheels with the soil surface. The main dependencies under applied dynamic loads were soil resistances to compression and shear. A method of theoretical study of the traction and coupling properties and passability of wheel propulsors when driving on dirt surfaces was used.

Scientific novelty and results. The result of the theoretical studies has been the development of optimization issues for the propulsers of the designed MPWV designed for operation and movement on soil surfaces and the rationale for the optimization algorithm. The novelty lies in the fact that when considering the process of interaction of a wheel with a soil surface, modern dependences of soil resistance to compression and shear are applied. They are based on the use of coefficients values in the equations reflecting a particular physical state of the soil surface and describing these processes, and which differ from empirical coefficients used in most studies. The research also uses the modern idea of replacing an ordinary wheel with a hard one, of a larger diameter, which allows analytical studies to be carried out in a wide range of propulsion parameters including the physical and mechanical characteristics of the soil surface.

Practical significance. The above optimization algorithm allows at the design stage of the wheeled vehicle propulsion to determine its towing and coupling properties and its passability when driving on a groud surface.

Introduction. Currently, intensive work is underway to create a terrestrial all-terrain electric vehicle, in particular wheeled and tracked vehicles with specific drive wheels. At the same time, scientific methods for ensuring the mobility of such machines at the design stage are absent.

The purpose of the study was to develop a set of full-scale mathematical modeling that could allow simulating the movement of wheeled, tracked and two-link tracked vehicles in real time on a humancontrolled computer.

Methodology and research methods. The paper discusses the method of selecting the required mechanical characteristics of the individual drive wheels of a wheeled, tracked, as well as a two-link tracked vehicle that provides the required level of average speed in statistically specified driving conditions.

Scientific novelty and results. The article presents mathematical models of wheeled, tracked and two-link tracked vehicles, on the basis of which a complex of full-scale mathematical modeling was built. The dependences characterizing the interaction of the mover with the support base have been given. The main capabilities of the complex of natural-mathematical modeling and its composition were described. To conduct numerical experiments, a route synthesis method has been developed, which consisted in calculating the road curvature and the interaction coefficients with the reference base on the basis of known statistical data (correlation functions). When making virtual races, a group of test drivers collected data on transmission modes and average speeds for various maximum power of transport vehicles.

Practical significance. The processing of the obtained information has allowed the writers to formulate requirements for long-term and short-term operating modes of traction electric motors, as well as for the necessary zone providing high operating efficiency. The proposed method made it possible to select the characteristics of an electromechanical transmission taking into account the turning particularities of a wheeled, tracked and two-link vehicle.

Introduction. Supporting rollers with an external rubber element are used in the design of the caterpillar propulsion. The durability of the support roller is limited by the durability of the rubber element. The causes of destruction of the rubber element are wear on the outer surface and fatigue failure of the rubber. To assess the magnitude of these factors, it is necessary to know the stress-strain state of the rubber element of the outer rubber element.

The purpose of the study was to assess the influence of the structural parameters of the supporting roller rubber element, namely, the influence of the inclination angle on the lateral surface of the rubber element in its stress-strain state as well as the forces of friction in the rubber element contact area with the running road of the link.

Methodology and research methods. When determining the stress-strain state, the mechanical properties of rubber at large deformations were described by the neo-Hook potential. The value of the radial force acting on the supporting roller was set taking into account dynamic loads during oscillations of the free track deviation.

Scientific novelty and results. For the considered design options for the rubber element, the following things were determined: specific strain energy; movement of the rubber element along the surface in the area of contact with the road; contact pressure of the rubber element on to the running road; the work of friction forces of the moving rubber element with the road in the area of contact. It has been shown that the concentration regions of the specific strain energy and the regions of maximum specific work of the friction forces on the surface of the rubber element coincided with a slope of the generatrix of the lateral surface of 10° and 15°.

Practical significance. Based on the results obtained, the advantage of a trapezoidal cross section with an generatrix inclination angle of the rubber element lateral surface of 20° was shown.

Introduction. The cardan drive is a powerful generator of torsional and crooked movements, perceived subjectively as vibrations acting on components of the drive and structurally associated vehicle mechanisms. Torsional, bending and longitudinal vibrations of the “cardan drive” system are the main causes of the contact surfaces wear of nodes and their elements under the influence of force factors acting force and torque. One of the main reasons for the cardan transmission failure is the wear of its components and parts, which necessitates the solution of a complex of problems.

The purpose of the study was to improve the quality of driveshafts manufactured by Belkard Ltd. Methodology and research methods. The designs of new-generation driveshafts were being developed taking into account the changes in the elements manufacturing technology and the use of progressive materials.

Scientific novelty and results. New solutions were applied in the design and manufacturing technology of the hinge assembly. Low-hardened-ability steel 60PP was used to manufacture the crosspieces of the hinge assembly at the automotive enterprises of the Commonwealth of Independent States practically for the first time, due to which higher technical and economic indicators of the hinge assembly have been obtained. The problem of a movable splined joint of a cardan drive was solved, the design of which included an antifriction polymer coating of the splines and effective sealing of this joint. In order to increase the connective reliability of the universal joint transmission and the mating units, flange forks with end teeth were developed. The use of joints of equal angular velocities and cardan shafts pipes made of polymer composite materials was noted to be a promising direction in the design development of cardan gears. An automated virtual test complex was created. The priority of automotive components of new designs and developed technologies was protected by patents of the Republic of Belarus, the Russian Federation, Ukraine.

Practical significance. Standard documentation regulating manufacturing technology and quality control has been developed and approved in the prescribed order. New designs were typical as to their transmitted torque, joint dimensions, spline joints, and connecting elements. A newly-created automated virtual test complex allowed to reduce the time of new cardan gear designs development.

Introduction. The object of study was a control system for changing the trajectory of the vehicle. The subject of the study were ways of maintaining a given trajectory of the vehicle based on the method of calculating solids dynamics. The study of the influence of transmission and suspension on the change in the trajectory of the vehicle was not considered and was beyond the scope of this article.

The purpose of the study was to develop a control model for changing the vehicle's trajectory using the example of a two-axle all-wheel drive truck, including subsystems – transmission, suspension system and steering.

Methodology and research methods. The vehicle was described as a system of solids connected by hinges and force interactions and compiling a set of typical elements of a software package. According to this description of the system, the software package automatically generated systems of equations of motion and relationships. The equations were solved using the implicit numerical method with variable pitch and automatically accurately controlled.

Scientific novelty and results. The paper considered the formation of the law of steering angle control to maintain a given trajectory. A detailed description of the developed simplified control model and analytical dependencies has been made for setting model parameters. An example of the selection of coefficients for its adjustment was demonstrated, recommendations for other types of calculation modes were proposed. In the work, an example of calculation was shown corresponding to a rearrangement of the vehicle with a subsequent return to the original lane. This example proved the adequacy of the model.

Practical significance. The developed mathematical model can be use for calculating the simulation of driver-driven vehicles, unmanned vehicles and adaptive driver assistance systems in the calculating systems of solids dynamics. Dynamic models can be also used to calculate the loads on the vehicle's load-bearing system, parts of the suspension and steering systems, etc.

Introduction. In order to lower the temperatures of forced advanced diesel engines parts and thus increase their reliability an increase in the intensity of thermal conductivity in their cooling cavities is required. For this purpose heat carriers with an increased coefficient of thermal conductivity were created, which were stable two-phase suspensions based on an aqueous solution of ethylene glycol and solid multigraphene nanoparticles with a high coefficient of thermal conductivity.

The purpose of the study was to numerically and experimentally determine the effect of the increased heat conductivity coefficient of two-phase heat carriers “base fluid – solid nanoparticles of multigraphene” on the heat transfer under operating conditions typical of the engine cooling system operation. These conditions were simulated on an experimental setup with CFD-computer modelling. The increased coefficients of thermal conductivity from the heated wall to the base fluid and to the two-phase coolant were compared under the same test conditions. The increased coefficients of thermal conductivity from the heated wall to the base fluid and to the two-phase coolant were compared under the same test conditions. Methodology and research methods. The temperatures of the liquid and the metal wall of the test section were measured on the experimental setup operating in a stationary heat transfer mode. At the same time, the parameters that occured in the engine cooling systems such as: the heated wall washer circuit, design features of the cooling cavity, artificial turbulization of the fluid flow, etc., – were unchanged. When determining three-dimensional fields of coolant velocities along the length of the tested section, as well as fluid and wall temperatures in at any point of the computational model, a numerical estimate of the heat transfer coefficient for coolants was carried out by computer simulation and by computational fluid dynamics (CFD).

Results. The effect on the heat transfer of the increased coefficient of thermal conductivity of multigraph particles heat carriers has been established. The presence of multigraphene nanoparticles in a suspension having a thermal conductivity coefficient of 0.85 W/m·K led to an increase in heat transfer intensity by 30% compared with the base liquid. The obtained experimental results were processed in similarity numbers, which made it possible to obtain the criterion equation for heat transfer under forced convection and turbulent flow of suspensions “liquid – solid particles”.

Scientific novelty is due to the receipt of new data on heat transfer from a heated wall to two-phase heat carriers “base fluid – solid nanoparticles of multigraphene”, as well as the receipt of a new criterion equation for calculating the heat transfer intensity in the cooling systems of internal combustion engines when using such two-phase heat carriers with an increased thermal conductivity.

The practical significance of the results of the work is to increase the reliability and ensure the operability of promising forced engines by reducing the high temperatures of the parts that surrounded and limited the combustion chamber. Heat transfer intensification in the cooling system will reduce the volume of coolant in the circuit and improve the overall dimensions and heat and power characteristics of the heat exchangers of the system.

Introduction. The following gases can be used as fuel in internal combustion engines: propane, butane, methane. Depending on the state of the gas location the fuel supply systems of the engine will vary. Currently, it is customary to distinguish six generations of fuel systems that are used to supply gas fuel to the engine.

The purpose of the study was to make a research of gas fuels and modern (sixth generation of gas cylinder equipment (GCE)) gas fuel system with the possibility of its operating on the gas-diesel. Another task was to perform a simulation of the gas-diesel engine working process in order to study the technical and economic performance indicators of the engine.

Methodology and research methods. The study was carried out by means of mathematical methods and the method of full-scale experiment.

Scientific novelty and results. The analysis of gases used in internal combustion engines as fuel was made. A modern gas engine fuel system and a variant of its work in the gas-diesel process were considered. The modeling of the working process of a gas-diesel engine was performed. The results of the design study were confirmed by the data obtained in the course of a full-scale experiment (the tested gas-diesel engine GD-243).

Practical significance. A variant of the operation of the modern (sixth generation of GCE) fuel system for the gas-diesel process (new facility) has been proposed, and a new dependence was obtained for the influence of the size of the diesel fuel ignition portion on the lower calorific value of a mixture unit (for example 1 kg) of gas (propane-butane) and diesel fuels, and, as a result, on the power and fuel consumption of the engine. The results obtained may be of interest to specialists in the appropriate direction.