bluuebunny/crossref_metadata_2025 huggingface dataset:
Age of aerodynamics of automobiles
Authors: Korolev E. V , ZHamalov R. R , Bernackij V. V
Published: April 2022

The article analyzes the time variation of the values of the coefficient Cx and the aerodynamic factor for passenger vehicles of leading companies. Calculated equations of aerodynamic indexes are presented, both for the whole array of automobiles and for breaking them into classes according to the European classification. The analysis uses aerodynamic indicators of the main types of bodies of vehicles obtained both during road tests and in experiments in wind tunnels with full-scale objects. Examples are given of the discrepancy between aerodynamic indicators and the results of the correlation studies of automobiles produced under different conditions, in different wind tunnels and its comparison with road tests. The reasons for these discrepancies are indicated. Examples are given of the change in aerodynamic indicators from the time of the release of generations of some brands of automobiles. The best and worst vehicles in aerodynamics for all six classes of European classification are indicated. The novelty is the determination of the regularity of the change in aerodynamic parameters, in particular of the aerodynamic factor, for the whole period of development of motorization, which requires the use of a large data set. The results of the analysis are also given. The result of the analysis is the conclusion that the amount of the aerodynamic factor of passenger vehicles is decreasing for the whole time of automobilization with a change in the external form of the body.
A crane-manipulator transfer position impact on a chassis loadings of a base vehicle
Authors: Lagerev A. V , Lagerev I. A
Published: April 2022

In the article it was analyzed the influence of the configuration of the crane in transport mode on the loading of the suspension base chassis (truck). To do this a mathematical model was developed to represent motion equations of the system of lumped masses connected by elastic-dissipative ties. Integration of the motion equations takes into account the influence of the surface roughness of the support base and the load moment of the crane-manipulator. Deformation and efforts in the suspension are evaluated based on the static and dynamic components, calculated using the developed model. Calculations are made for a three-axle truck KAMAZ 53215, equipped with a Kanglim KS3105 crane. The results of computer simulation using mathematical models have shown that the location of the crane boom forward leads to a significant overload of the front suspension of the base chassis. The location of the crane boom backwards leads to unloading the front suspension of the base chassis. However, overloading of the rear suspension is much lower, as the rear suspension of the vehicle are mostly oriented on the perception of the weight of the payload. When moving the base truck with the transport position of the crane boom forward dynamic component of the load on the front suspension is higher by 10...15% higher than in the transport position of the crane boom backwards, and the load on the rear base of the chassis is lower by 8...9 %. The developed mathematical model and calculation methodology should be used for the rational choice of the transport configuration of the crane with specific given characteristics of the basic truck and cargo load.
Limits of applicability of the standard method for estimating the torsional rigidity of spatial frames of buggy vehicle
Authors: Bazhenov E. E , Bujnachev S. K , Kustovskij A. N
Published: April 2022

The article provides an assessment of the limits of applicability of the standard methodology for estimating the torsional rigidity of spatial rod-bearing systems of automobiles. Torsional stiffness, as shown by numerous studies and practices, is one of the most important indicators of the carrying capacity of vehicle bodies (frames) of all types of vehicles - including such highly specialized ones as buggy. The authors show on the example of the bearing structure of an off-road vehicle of the “buggy” class that the general application approach to the assessment of the torsional rigidity of the bearing systems using torsion deflection stumbles upon limitations when it comes to spatial frames of complex construction. These restrictions are dictated by the difference in stiffness between design zones (zones should be understood as the floor area, the waist area and the roof area), which is reflected in the significantly different distribution of displacements in them. As a result, it becomes impossible to unequivocally give an opinion on the torsional rigidity of the frame using torsion deflection, since it is impossible to select a reference point in any of the zones (or the entire zone) to adequately describe the torsional rigidity of the whole structure (or a separate substructure). In this regard, the authors proposed the limits of applicability of the traditional method for estimating the torsional stiffness of a spatial core structure, and also proposed a method for overcoming these difficulties encountered when trying to assess the torsional stiffness of the supporting structure. The object of the research is a typical spatial frame of an all-terrain automobile of the D2 class buggy.
Technique for evaluating the efficiency of a V-belt variator in a light vehicle
Authors: Luk'yanov A. S , Starikov A. I
Published: April 2022

V-belt variators with automatic pressure mechanisms have prevailed in light vehicles, such as scooters, snowmobiles, quads, all-terrain vehicles, etc. In this regard, it is necessary to develop a methodology for assessing the efficiency of the variator to determine the necessary parameters and performance of the V-belt variator of light vehicles. These vehicles have a small mass (up to 750 kg) and cost and, as a rule, are equipped with engines of low power (up to 75 kW). The constructive simplicity and high manufacturability of the manufacture of a few parts of the V-belt variator, and therefore the lowest cost of them, with a sufficiently high reliability level today provided the variator with the maximum value of the indicator in the form of the “reliability / cost” ratio. This is one of the factors that allowed the V-belt variators to gain leadership in the transmissions of these vehicles. To assess the efficiency of the V-belt variator of a vehicle, a method for estimating the instantaneous positions of the variator operation is necessary, which will help determine the instantaneous values of the necessary parameters and give an opinion on the performance of the variator in this state and the subsequent transient, its speed and efficiency. The technique is based on the determination of the axial forces created by the pressure mechanisms and the radial forces arising from them, the tension forces of the belt branches, taking into account the circumferential force from the transmitted torque. The peculiarity of this technique is to determine the exact position (angles of inclination and direction) of these forces both in the plane of the belt contour and perpendicular to it. The developed technique allows to estimate the work of the designed V-belt variator in all possible engine modes. In addition, the methodology shows the reasons for the inefficient operation of the variator, and also provides recommendations for their elimination. Further development of this technique will allow the design of new constructions of variators with the necessary properties.
Investigation of the main factors of the process of ignition of a homogeneous mixture from compression in an ICE
Authors: Makarov A. R , Smirnov S. V , Kostyukov A. V , Ponomareva K. A
Published: April 2022

An overview of the advantages of an engine with the ignition of a lean homogeneous mixture from compression (HCCI), among which, above all, economic and environmental indicators are presented. There were considered the disadvantages of this engine, hampering the release of batch production, and the main is the difficulty in providing in the combustion chamber the conditions for self-ignition of the working homogeneous mixture near TDC in the entire range of engine operating conditions. The ways of solving the problems of controlling the ignition of the working mixture in the combustion chamber, reducing the noise level and fighting the occurrence of shock loads with increasing load, starting the cold engine and improving the engine with the HCCI process are presented. The main ones can be a combination of distributed and direct injection using variable valve timing and exhaust gas recirculation, the joint use of controlled turbocharging and exhaust gas recirculation, a change in the heating of the working mixture at the inlet to the engine, external and internal exhaust gas recirculation (EGR) phases of gas distribution, regulation of the chemical composition of fuel and changes in the intensity of heat transfer and the dynamics of temperature growth in the cylinder, primarily due to changes in the piston crown temperature. The results of computational studies of the influence of various parameters on the process of ignition of a homogeneous mixture on compression are presented. It is established that the greatest effect on the process of homogenization of the air-fuel mixture is caused by an increase in the surface temperature of the bottom of the piston. Reducing the diameter of the fuel droplets from 0.1 mm to 0.03 mm results causes an increase in the relative mass of evaporated fuel by a factor of 2. Increasing the temperature of the fuel at the inlet also effectively increases the relative mass of the evaporated fuel.
Modeling of the mechanism of appearance of external infrasound of land vehicles
Authors: Nyunin B. N , Grafkina M. V , Sviridova E. Yu
Published: April 2022

The main contribution to the acoustic pollution of residential areas is made by land vehicles including automobiles. Most scientific publications are devoted to the study of audible sound, its sources in the vehicle and the development of measures to reduce it. According to the authors opinion, at present the problem of the emergence and spread of infrasound in residential areas, and, accordingly, its negative impact on people and the environment is underestimated. Hence the development of computational and experimental methods for studying the mechanism of the appearance of infrasound from a vehicle is a very urgent problem. A large proportion of the acoustic radiation from the vehicle falls on infrasound and low-frequency range of frequencies. Depending on the design of the automobile, the occurrence of internal infrasound can be caused by the engine's vibrations as a rigid body on its suspension, flexural and torsional body oscillations, the impact of the oncoming airflow. Measurements of internal and external infrasound were carried out. A computational model is proposed and an assessment is made of the influence of the design features of the vehicle on the level of infrasound. Calculation studies of the mechanism of the appearance of an external infrasound of a vehicle have shown that its frequency and level depend on the speed of movement, the drag coefficient, the length and the Strouhal number. A significant source of infrasound in the automobile are also wheels that perform rotational and translational movements in the oncoming air stream. Calculation of five wheel harmonics for a automobile at various speeds of movement is carried out, existing dependences are revealed. The results of the calculation showed that exceeding the normative values of infrasound is possible only in residential areas adjacent to the traffic flow with speeds of over 80 km / h.
Determination of the time and the path of acceleration of a vehicle equipped with a gearbox without switching-off of the power flow
Authors: Ryabev A. V , Parfenov A. P
Published: April 2022

Gearbox with gears switching without switching-off of the power flow (GWSPF) are known to spread on agricultural tractors, which have a large number of gears to support various technological processes. However, the expediency of using them on high-speed crawler machines (HSCM), which has the limited number of gears, is not obvious due to greater complexity and cost, as well as additional power losses compared to the widely used simpler mechanical gearboxes. For HSCM, as well as vehicles with a number of gears of more than five, the advantages of shifting without breaking the power flow can outweigh their disadvantages mentioned above. For army crawler machines used in military conditions the time and the path of dispersal can be decisive. The paper gives a comparative evaluation of HSCM equipped with a five-speed mechanical synchronized gearbox and GWSPF, which showed the advantages of gear shift without breaking the power flow in reducing the time and acceleration path by 1.3 and 1.2 times, respectively. To perform the calculations, a technique and algorithm for calculating the parameters of the acceleration of the machine was developed in comparison with the approximate method of graph-analytic integration of professor N. Yakovlev. The exact calculation technique is based on solving a differential equation relating the acceleration to the speeding up parameters of the crawler machines under the initial conditions corresponding to the beginning of its motion. The methodology and calculation algorithm can also be used to determine the traction-speed and fuel-economic qualities of other vehicles, including automobiles.
The training of specialists in sphere of power engineering
Authors: Fomin V. M , Gots A. N
Published: April 2022

The tasks of this work are: analysis of trends in the development of engine building, which relates to the important direction of power engineering, and assessment of the quality of training of engineering and technical specialists in domestic universities, investigating the conformity of their professional knowledge with modern requirements. It is emphasized that the process of training engineering and technical personnel in the field of power machine-building specializing in internal combustion engines should be constantly improved taking into account the rapid development of modern engine building. The factor of the qualitative level of training specialists possessing the necessary knowledge in the field of technology and the development of highly efficient engines acquires important state significance. The tendencies of development of engines for transport and transport-technological facilities are considered. It is noted that foreign companies have far gone in the implementation of innovative technical solutions associated with a significant complication in the design of engines, systems. Successful practical implementation of these solutions has become possible, among other things, thanks to the high level of training of foreign specialists with the necessary knowledge in the field of technology. The problem of the emerging decline in the level of university training of engineering personnel in the sphere of Russian energy engineering is analyzed. Moreover, over the past decades, Russia has experienced a tangible need for skilled engineers and technologists, who have been and continue to be the backbone of domestic production. It is emphasized that all this can lead to the loss of promising technologies in the production of competitive domestic engines, and will cause catastrophic consequences for the country's economy and its defense capability.
Ways to improve diesel engine fuel systems
Authors: Strel'cov R. V , Berdnikov A. A , Vasil'ev V. G , Dyunov V. A , Mel'nikov E. I , Ladanov V. I
Published: April 2022

The article discusses issues related to the purpose of supplying fuel to diesel engines, presents the requirements for this system. An analysis of ways to improve the fuel systems of diesel engines is done. The principle of operation of the high-pressure fuel pump is described, which provides accurate dosing of fuel in accordance with the engine operation mode and delivers it at a set time to the injector with a given intensity. Special devices for turbulence of the fuel in the combustion chamber, film mixing, pressurization and others make a great variety of requirements for the distribution of fuel in time and environment. Meeting these requirements is a complex and time-consuming task, one of such devices is the nozzle. The nozzle directly atomizes the fuel in the combustion chamber of a diesel engine under the influence of a pressure pulse generated by a high-pressure fuel pump. It is possible to fulfill the changing requirements for the injection characteristics if the design of the fuel system is changed accordingly. First of all, it is necessary to lose the essential shortcomings inherent in modern fuel systems, namely: some inconsistencies of the principle of operation of individual elements of the fuel system with the flow conditions of the diesel engine process; poor distribution of fuel over time; initial conditions instability. The article presents a developed device for shutting off the fuel supply to the nozzle, providing the possibility of diverting fuel that has not entered the engine cylinder as a result of leakage between the parts of the nozzle and disabling fuel supply to the nozzle when the engine cylinder is turned off to improve the quality characteristics of the diesel engine fuel system.
One-dimensional univariate work simulation of turbocharged engine with restrictor before compressor inlet
Authors: Tatarov M. G
Published: April 2022

All over the world, and in Russia, especially, the engineering sports competitions "Formula Student" are gaining popularity. Formula Student - is an international competition held among students of technical universities, in order to get practical knowledge in the process of developing and building a Formula student class racecar. When creating a car, you must adhere to strict technical regulations. So, one of the limitations is the maximum engine capacity - 710 cubic meters, which, in itself, implies the use of a motorcycle engine. A mandatory condition is the presence of a restrictive nozzle (restrictor) which have 20 mm diameter and placing in the inlet system. This causes many problems when designing engine intake systems. However, it allowed using various systems of pressurization of engines. The most common and effective is the installation of the turbocharger. This helps to solve the problem of insufficient amount of air that entering to the engine. Moreover, with the correct configuration of all components of the intake system in combination with the turbocharger, it is possible to achieve power and torque exceeding the standard engine without a restrictive nozzle. The article presents the data obtained in the course of a one-dimensional simulation of the KTM LC4 engine with a turbocharger and a restrictor in the intake manifold. The purpose of the work is to reduce the negative influence of the restrictor on the power and torque parameters of the KTM LC4 engine by using a turbocharger. In the course of the work, an analysis was made of gas-dynamic processes occurring in various parts of the engine intake system that affect its output values based on numerical studies. Because of the research, the dependences of the output parameters of the engine (maximum power and maximum torque) on the parameters, shapes and sizes of various components of the intake system with a turbocharger.
Efficiency of application of direct-drive circuit for improvement of starting characteristics of gas turbine engine
Authors: Chechulin A. Yu , Krivoshev I. A
Published: April 2022

The effectiveness of measures to improve the starting characteristics of gas turbine engines (GTE) is considered. To improve the reliability of the GTE launch, it is proposed to use the so-called gearless GTE scheme, created for a “more electric aircraft”, which uses an integrated high-speed starter generator and electric drive units for fuel, oil and other life support of gas turbine engines. With the help of a nonlinear dynamic mathematical startup model, the effect of the magnitude of the given moment of inertia of the rotor on the starting characteristics of the gas turbine engine is evaluated. Change it in the direction of reduction was carried out by replacing the gearbox with attachments to one unit a high-speed starter-generator, installed coaxially with the rotor. Determination of the value of the given moment of inertia of the rotor, aggregates, bearings was carried out using the developed 3-DCAD-models. In the mathematical model of start-up, the thermal state of the oil system, the mechanical power losses for rotating aggregates, bearings, gears are taken into account. The quantitative dependence of the starting characteristics on the moment of inertia of the GTE rotor and other factors is established. For comparison of the basic APU and APU of the direct-drive circuit simulation of the start in the most stressful operating conditions P H = 101,3 kPa at low negative temperatures t H = -40 °C and under normal conditions P H = 101,3 kPa and t H = +15 °C, for “cold” and “hot” state of the engine before starting was made. The tendencies of the moment of inertia of the rotors of the executed and newly created GTE are analyzed. It is shown that the gearless APU in comparison with the basic APU due to the reduction of the moment of inertia by 9,68 % and the reduction of the oil pumped volume in the oil system has a significant improvement in the launch characteristics under ground launch conditions ( P H = 101,3 kPa).
Frequency analysis of the system of stabilization of vertical reactions on the wheels
Authors: Al'salamekh Bal'sam , Ryazantsev V. I
Published: April 2022

Increasing importance is given to the issues of road safety. Perfection of modern designs allows automobiles to move at a high enough speed. Taking into account the considerable size of the territory of the state and the variety of roads on which motor transport is operated, there may be areas with a pronounced periodic profile close to a sinusoid with different wavelengths from 0.5 to 1.5 m. On a road with a wave length of a periodic profile of 1 m at a vehicle speed of 36 km / h, the suspension system receives kinematic excitation at a frequency of 10 Hz. This value of the exciting frequency is in the range of real values of the natural frequencies of the wheels in the suspension systems of vehicles (5 ... 12 Hz). The resulting fluctuations in the vertical reactions of the road to the wheels lead to a decrease in the stability of the vehicle's movement. To solve the task of combating this phenomenon, a new method of increasing the stability of the vehicle's motion is designed - the method of controlling the vertical reactions of the road to the wheels when the car moves along periodic irregularities. The paper offers a frequency analysis of the properties of the stabilization system of vertical road reactions to wheels. Various variants of the control organization, algorithms formation using different types of regulators are considered. In particular, control options are considered with the use of proportional and proportional-differential regulators. The issue of the power consumed to control the system for stabilizing vertical reactions of the road to the automobile's wheels is considered, depending on the frequency of excitation by the periodic profile. The performed analysis shows that correctly selected regulators reduce the control forces in the control drive, the power required for control, while the result of control, stabilization of the vertical reaction of the road to the wheel, becomes more significant.
Processes occurring in an engine with an unconventional duty cycle
Authors: Berdnikov A. A
Published: April 2022

An internal combustion engine is a thermal machine that converts thermal energy into mechanical energy. Currently, the existing engines operate in cycles of Otto, Diesel and Sabate-Trinkler. Such cycles are usually called traditional. As is known, traditional internal combustion engines do not have a high coefficient of efficiency due to large losses of heat with exhaust gases, heat removal to the cooling system, etc. The reserves of increasing the efficiency are very high. However, modern engine building has reached a high level and further improvement of the working process in traditional cycles is already ineffective. The article proposes a non-traditional seven-stroke internal combustion engine and examines the processes occurring in the cylinders of such an engine. In the main cylinder of the engine, the working cycle proceeds as in a traditional four-stroke internal combustion engine: at the first stroke, there is an intake, on the second stroke - compression, on the third - combustion and operating stroke, but in the fourth cycle the exhaust gases are not diverted from the cylinder, but are sent to an additional cylinder - there is a continued expansion of gases (operating stroke). At the fifth bar, the exhaust gases are compressed in an additional cylinder, and water is supplied at the end of the compression. Selecting heat from the heated parts of the cylinder-piston group and compressed gases, the water evaporates, and the expanding steam performs useful work (the sixth stroke is the operating stroke). At the seventh stroke, the piston moves to the top dead center, displacing the steam with the exhaust gases. Preliminary calculations showed that the maximum pressure of the seven-cycle operating cycle of the internal combustion engine can reach up to 20 MPa, this increases the power and fuel economy of the engine. The injection of water somewhat reduces the maximum cycle temperature and the toxicity of the exhaust gases. Such advantages give reason for the implementation of the working cycle of the internal combustion engine in a seven-cycle scheme.
Automation of the control of the differential lock in the transmission of a multi-axle wheeled vehicle
Authors: Safonov B. A , Kotiev G. O , Smirnov A. A
Published: April 2022

Due to intensive development of multi-axle wheeled vehicles in the Russian Federation, there is a need to improve its performance characteristics such as flotation, which in turn increases the average speed of traffic in difficult conditions. Increasing the flotation and retain mobility in difficult road conditions is facilitated by intensive management of differential locking clutches. However, for a multi-axle wheeled vehicle, the number of differentials in the transmission makes the task of controlling the locking clutches difficult for the driver. The modern development of microprocessor technology allows the creation of automatic transmission control systems that implement the specified law of switching on and off the differential locking clutches. The method of definition of the law of control of differential locking clutches for a multi-axle wheeled vehicle is shown in the article. The research is carried out with the help of the mathematical simulation model of the curvilinear motion of the vehicle in the Matlab Simulink software package. The law of inclusion of clutches blocking is based on definition of a difference of speeds of rotation of output shafts of a differential and considers various radii of wheels rolling and also an opportunity of reliable switching of differential locking clutch. The sequence of switching on of clutches for locking different differentials in the transmission is determined. The law of deactivation of the differential lock is based on the criterion of maintaining the steering and maneuverability of wheeled vehicle, which contains of admissible increase in the turning radius by 10% in the case of a locked transmission with respect to the turning radius for the differential transmission at the same speeds and steering angles. Numerical simulation is carried out for curvilinear motion along different support surfaces of a wheeled vehicle 8 × 8, in the transmission of which there are 7 differentials. It is established that the creation of a control system based on the proposed law of wheeled vehicles differentials control can be realized without significantly complicating the construction of existing mechanical transmissions by installing additional speed sensors on output shafts of differentials.
The new standard on the administrative aspect of registration changes in the design of the vehicle
Authors: Girutskiy O. I , Kirillov K. A
Published: April 2022

Eurasian integration in the economy makes it possible to establish unified principles and mandatory security requirements in standardization, metrology, accreditation, assessment of compliance, oversight (control), and eliminate technical barriers to trade. The system of technical regulation in the automotive industry is built according to international harmonized requirements, taking into account the safety of traffic. At the same time, the main instrument for implementing the technical regulations of the Customs Union “The Safety of Wheeled Vehicles” (TR TS 018/2011) is the development of interstate standards. The article presents the program of interstate standardization for vehicles in operation, which is carried out by the Interstate Technical Committee for Standardization “Road Safety” (ITC 278). Thus, for the first time, a standard has been developed for the administrative aspect of recording changes in the design of vehicles at the stage of the life cycle of operation, which will become effective from February 1, 2018. With the help of infographics, a clear algorithm for registering changes in the design at the stage of operation in the Russian Federation is presented. Independent professional multi-stage security design verification is adapted to the current realities and allows supporting the technical initiative of vehicle owners. The use of unified forms and this methodology is the next step to improve the regulatory and technical basis of technical regulation in the automotive field. The application of the official document will promote individualization and engineering creativity. Also, a new standard was announced for methods of monitoring the technical state at the operational stage. The article contains comments on the current legislation, and the conclusions contain the prospects for further scientific research. The information on the preparation of national regulations that establish relations in the field of the operation of road transport is also presented.
The study of “real-time” simulation of planar curvilinear motion of six-wheel drive vehicle
Authors: Buzunov N. V.
Published: April 2022

The main focus of this research is to verify the mathematical model of the vehicle motion, which operation is carried out in real time. The subject of this study is the model, which describes planar curvilinear motion of six-wheel drive vehicle. Correct operation of this model is based on the methods and criteria currently used in the foreign and domestic research. The estimating parameters for the model are the linear and angular kinematic characteristics of planar motion of the vehicle. The assessment criterion is the value of relative error no more than 10% when comparing at the same time the parameters of the model with the parameters of the reference model, which correctness of operation is confirmed by the results of experiments on the real object. Research is carried out in several stages at different driving modes and various parameters of the simulation. The duration of the test "races" is 30 sec. At the end of each race the comparison of the results with the data of "reference" model is made and determination of relative error of simulation and its comparison with the established criterion of correctness are done. According to the study was found out that the mentioned real-time verification of the model satisfies a predetermined criterion of verification when using step of no more than 0,001 sec. By increasing the steps of realization there are significant deviations of the model parameters on the results of "reference" model, in this case, the real-time model can be used to address a limited range of purposes. Reducing simulation step facilitates approximation to the behavior of the test object to the "reference" but in real-time operation this approach requires a significant increase in computing power.
Modernization of the cooling system for diesel engines of the YAMZ family with the aim of reducing cavitation damages
Authors: Strel'tsov R. V , Vasil'ev V. G , Arabyan A. K , Mamoshin A. I
Published: April 2022

The article deals with issues related to the modernization of diesel engines to reduce their cavitation damages. During the operation of diesel engines, local fractures can occur, as a rule, the causes of these disruptions can be the vibrations of the walls of cooling cavities of diesel engines, resulting in ruptures of the liquid, which leads to higher pressures, temperatures and potential differences in the cooling sphere. These factors have a destructive effect on the surface of parts, washed with coolant. To maintain a normal thermal regime, it is necessary to remove excess heat from heated parts, that is why the cooling system is designed. One of the promising trends in the development of this system is the increase in the average temperature of the cooling liquid in the water path of internal combustion engines above 100 ° C with a corresponding increase in pressure in the jacket space, which eliminates the boiling of water. As the temperature of the coolant rises, the fraction of heat carried away with the cooler decreases, and the period of self-ignition delay decreases, and the degree of increase in pressure during combustion decreases, which has a positive effect on the operation period of engine parts. Analyzing the reliability of the liquid circuit, it must be taken into account that the efficiency of the pump depends largely on the temperature of the coolant. At a coolant temperature close to the boiling point of the coolant, cavitation phenomena occur, which are manifested in a sharp drop in the productivity of the pump due to the appearance of air and steam bubbles in the liquid. It becomes difficult to ensure the non-cavitation operation of the water pump. Cavitation in the flowing part of the pump often leads to a violation of the circulation of coolant in the circuit and overheating of the diesel. The inclusion of a high-temperature cooling system in the water system of the mixing and supporting device parallel to the water pump is one of the simplest and most effective ways to increase the pump's available cavitation supply.
The method of simulating the loading of boosted diesel engine during start-up at low ambient temperatures
Authors: Bondar V. N. , Kukis V. S. , Malozyomov A. A.
Published: April 2022

The paper discusses the method of simulating the loading of boosted diesel engine during start-up at low ambient temperatures. To improve the reliability of the experimental evaluation of the results of diesel qualities the device simulating resistance to crankshaft turn over from the side of transmission elements of object was developed. The device provides the ability to control and change the moment of resistance to crankshaft turn over. The method of start-up testing of high performance engine with the device in a climatic chamber was developed. The engine is equipped with prior-start preparation and start-up facilitation systems. Loading parameters for type 12ChN15/16 engine object. In accordance with the test program 20 experiments were conducted at ambient temperatures of 5, minus 5 and minus 20 °С. The results of experimental studies confirmed the effectiveness and adequacy of the proposed method. It was revealed that crankshaft breakaway torque during engine acceleration does not depend on load of engine and oil viscosity (in the range of ambient temperatures during testing) and is determined by moment of inertia of the rotating masses. During diesel turn over load pressure is provided almost simultaneously with the start of engine crankshaft breakaway. Loading of device pump by pressure of 14 MPa leads to an increase of resistance to crankshaft turn over moment at an ambient temperature of minus 20 °С to 9% (from 883 to 970 N·m). According to the results of testing the recommendations for further improvement of the device to simulate loading of boosted diesel engine during start-up at low ambient temperatures were given.
The hydrodifferential rectifier of the moment of inertial automatic transmission of mobile machines
Authors: Greben'kov D. V
Published: April 2022

The article considers the possibility of using torque in the inertial-pulse automatic transmissions of a hydrodifferential rectifier, in the design of which hydraulic machines are used as free-wheel clutches. Unlike mechanical freewheel clutches, where the weakest of their links are the jamming bodies, in the proposed construction the jammed body is hydraulic fluid, which allows to eliminate the above-mentioned drawback and reduce wear. A kinematic scheme of inertial transmission with a hydrodifferential torque rectifier is given and the working process is described on three characteristic operating modes: stop, torque and direct transmission. Dependences for calculation of basic parameters of hydraulic clutches of a free wheel are given, and also theoretical and experimental results of researches of working capacity of the inertial hydrodifferential torque transformer are presented. An analysis of the results showed that with increasing internal leakage of the working fluid, which increase as a result of wear of the hydrodifferential torque rectifier, the power and torque on the shaft of the hydraulic machine will decrease, which in turn will decrease the efficiency of the hydrodifferential rectifier. The analysis of the results showed that at the beginning of operation the efficiency of the hydrodifferential rectifier is about 93% in the entire operating range. During operation, the efficiency of transmission decreases linearly and at a radial gap of 300 ÷ 350 μm is only 68 ÷ 63%. With further deterioration (radial clearance 350 ÷ 400 μm), the efficiency is practically not reduced. This indicates that the hydrodifferential rectifier of the torque has completely worn out and its replacement is required.
Experimental study of comparative indicators of agricultural tractors caterpillar drive
Authors: Kupryunin D. G. , Shchelnitsyn N. A. , Beyinenson V. D. , Fedotkin R. S. , Belyi I. F. , Revenko V. Y.
Published: April 2022

Rubber reinforced caterpillars are becoming more common in agricultural tractors, harvesters and military tracked vehicles. The use of rubber reinforced caterpillars comparing to metal tracks allow: to reduce on 25-30% the sealing effect on soil; ensure the movement of vehicle on the roads with asphalt pavement without its damage; to increase vehicle road speed to 40 ... 50 km / h; to reduce noise and to improve working conditions for tractor driver; to increase reliability. Nowadays there are no comparative results of experimental evaluation on the application of rubber reinforced caterpillars and metal tracks on tractors. Traction tests of tractors with rubber reinforced caterpillars abroad are conducted on a specially prepared supporting surface in the form of a rubber blanket, where tractors with metal caterpillar tracks could not be tested. In this case the obtained tractor traction characteristics differ significantly from the actual operation. The paper presents the results of comparative tests of VK-150 tractor manufactured at Volgograd tractor plant on stubble of winter wheat with rubber reinforced and metal tracks with open metal joints. It was found that the developed domestic machines and manufacturing technologies of rubber reinforced caterpillars for agricultural tractors provide equal traction parameters of tractor with series metal and rubber reinforced tracks in zone in the area of nominal traction forces for tractors of class 3. By set of technical characteristics chassis with rubber reinforced caterpillars perform better than chassis with metal caterpillars with open joints (in terms of vibration loading, noise and flotation).
Problems of process control for shifting gears on tractors without torque interruption
Authors: Timofievskiy A. A.
Published: April 2022

The article considers the problem of optimizing the process control for shifting gears on tractors without torque interruption. The opinion on the dynamics of process control for shifting gears is explained, it takes into account the occurrence of torque deficit in the shafts, when changing gear, and increasing of friction losses in spinning clutch. The formulas for calculating the dynamic parameters used in the mathematical model of the dynamics of the tractor when shifting gears without torque interruption are shown. With the help of the mathematical model developed in Scientific and Research Tractor Institute (NATI) for debugging the system of electro-hydraulic control of gear shifting process for CHN-6 tractor were calculated several variants of gear shifting. Particular attention is given to occurrence, development and completion of the power circulation process in the circuit of switched clutches, because the lack of circulation of power the majority of authors call the basis of optimal switching. The results of the calculations in terms of the circulation of power, failure to slipping of switching off the clutch and interlocking of switched on clutch are shown. Calculation results suggest that when the clutch of lowest gear is closed the torque growth in spinning clutch of switched on top gear causes an increase in friction losses of disks, which leads to a decrease in engine shaft speed and reduction of the tractor speed. The magnitude and duration of fall of the engine speed and the speed of the tractor are low, but due to a decrease in the speed of the tractor the moments of forces inertia are large enough and need to be taken into account in the calculations. In all experiments, where power circulation was present, it started earlier than top gear clutch created torque, which corresponds to the resistance movement. In all experiments, where power circulation was present, it ended as a result of reducing the pressure in the clutch booster of lower gear after its failure to spinning in the power circulation mode. The circulating power after the failure to spinning and clutch switching off is redirected to output shaft accelerating the tractor and accelerating the synchronization and interlocking of switched on clutch.
Analysis of design schemes of combination of vehicles towing elements wheel drives
Authors: Gorelov V. A. , Chudakov O. I.
Published: April 2022

The article presents an analytical review devoted to the design of combination of vehicles towing elements wheel drives in domestic and foreign automotive industry. Brief information regarding the developed mathematical model of linear dynamics for tractor unit with active towing element is given.
The choice of the main parameters of vehicles of classes A, B and C
Authors: Kravets V. N. , Musarskiy R. A. , Volkov S. A.
Published: April 2022

The object of the study are the vehicles of classes A, B and C on the European classification made in 2010 - 2015 in more than 80 enterprises in all automotive countries. The purpose of the study is to establish the dependencies curb and total mass of automobiles the main classification parameter is the overall length. The novelty of this work is that we studied a model of modern automobiles , while similar investigations were made on vehicles produced in the beginning of XXI century, most of which are now discontinued. Completed work is relevant because its results scientifically allow to choose when designing critical design parameters of passenger automobiles the curb and total mass. On the basis of statistical processing source data were obtained analytical and graphic dependences of curb and total mass of automobiles from their overall lengths in each class and, in addition, in the largest class C. These dependencies are set separately for sedan, hatchback, coupe and cabriolet automobiles. In total, were analyzed 289 automobile models. A large volume of the investigated models allowed to obtain statistically reliable results. The article shows that the accuracy from 7.5% to 14.4% of the dependency between mass and overall length of vehicles of all studied classes can be approximated by polynomials of second order. The results of the study are recommended for use in design and research organizations of automotive companies for a reasonable choice of design parameters of the designed passenger cars.
Energy savings for heating cabins of mobile machines and production facilities for their maintenance and repair
Authors: Mikhailov V. A. , Kutkov G. M. , Dmitriev M. I.
Published: April 2022

The ways of energy saving in air heating of cabins of mobile machinery (tractors, trucks, harvesters) and production facilities are discussed. It is shown that in the cabins of mobile machines with a relatively small volume with no exhaust ventilation to reduce energy consumption for heating, while regulating temperature at workplace and relative humidity, is to use partial recirculation of treated air. Specific recommendations for the heating of the mobile machine cabins, which is characterized by basic parameters such as thermal performance, air flow and temperature are given. It was found that the partial recirculation of the treated air in the cabin of the mobile machine has allowed to reduce energy consumption for heating in 1.94 times and provided on working place of operator normalizable relative humidity without any additional units for humidification. It is shown that in areas of larger volume, where maintenance and repair is carried out in the presence of local exhaust ventilation, standard for relative humidity could be provided only with humidifier. Thus in order to reduce energy consumption for heating it is necessary to dispose the exhaust air heat flow to preheat the incoming air using the heat exchanger-recuperator provided with an exhaust air dryer to avoid freezing of apparatus at low ambient temperature conditions. The filler of drying unit could be silica gel as water absorption by silica gel is accompanied by increasing treated air temperature and in the heating system it leads to energy consumption and is a positive characteristic.
Design features of fan assembly in automobiles
Authors: Petrov A. P. , Sinitsyn S. N. , Bannikov S. N.
Published: April 2022

Nowadays in the engine cooling system and in air-conditioning system of passenger compartment and cabin of tractor is applied a great variety of designs of fan units for the supply of cooling air. A distinctive feature of fan units of automobiles is that they need not only to supply cooling air, but also must make efficient use of air flow. This is not an easy task, because these two functions are almost always in conflict. The problem becomes even more complicated when a car air conditioner is installed. Efficiency factor of the incident flow is higher than the efficiency of the fan. It is therefore necessary to use more efficient the incoming air flow. The article analyzes the most common fan assemblies of automobiles used for the operation of the engine cooling and passenger compartment air conditioning system. Its strengths and weaknesses were evaluated. There were evaluated the most important characteristics: the effectiveness of the fan use, the rational use of air flow when the vehicle is moving, mass-dimensional characteristics and the noise produced by the fans in their work. The conclusions and recommendations for improving the fan installations were given. When choosing one or another variant of the fan assembly it is needed to take into account the features of the automobile design. High efficiency of fan can be obtained when the fan shroud has a full coverage of the radiator. In this case, for rational use of incoming flow is necessary to install in the fan cover the valves of a large cross-section in contrast to traditional, these valves must be driven to forced opening and closing.