卷 11, 编号 4 (2017)
- 年: 2017
- 文章: 12
- URL: https://journal-vniispk.ru/2074-0530/issue/view/3708
Articles
Development of an experimental research complex for determining parameters of interaction of a pneumatic tire with ground
摘要
When designing an all-wheel drive vehicle, an important task is to predict its traction properties and expected cross-country parameters. To solve such a problem it is necessary to have an adequate design model for interaction of a wheel propulsor and the deformable support base. The article deals with the problems associated with development of the test stand design, which allows to conduct fine experiments in the mechanical system “active wheel - ground” in a laboratory. The main tasks during the experiments on this stand are: simulation of the power and kinematic interaction of a real pneumatic tire (automobile wheel) with a deformable ground surface, the mechanical state of which can be varied; measurement of force and kinematic parameters of interaction in the system “tire - ground”; visualization of the process of unsteady interaction of the tire and the ground in the spot of their contact during acceleration, skidding and braking; development and creation of a measuring complex for assessing the physical and mechanical state of a ground massif. The authors reviewed the existing designs of similar stands and installations for determining the parameters of interaction of the wheel with the support base. Problems that need to be solved during the experiments are considered, namely: simulation of the power and kinematic interaction of a real pneumatic tire (automobile wheel) with a deformable ground surface, the mechanical state of which can be varied; measurement of force and kinematic parameters of interaction in the system “tire - ground”; development and creation of a measuring complex for assessing the physical and mechanical state of a ground massif. A set of measuring equipment is presented, with the help of which the physical and mechanical condition of ground conditions is evaluated during the tests. Investigations and experiments will make it possible to clarify the physics of the processes occurring in the spot of their contact, both from the tire side and from the ground.
Izvestiya MGTU MAMI. 2017;11(4):2-9
2-9
Necessity to create agricultural vehicles
摘要
To ensure harvesting and transportation of crops on soils with low bearing capacity, a number of designs of harvesting vehicles on caterpillar tracks have been developed. Currently, a large fleet of harvesting and transporting machines operates in the caterpillar drive in the Far East, the countries of the near abroad, the Baltic States, Central Asia, Cuba, Vietnam and China. The main distinguishing feature of this class of machines is the need to provide high cross-country ability with minimal destruction of the fertile soil layer. The most important requirements for caterpillar propulsors, presented by consumers, are requirements for ensuring performance on surfaced roads, reducing noise and vibration of parts, increasing transport and operating speeds, driving comfort, increasing of service life, reducing of negative impact on the soil. Agriculture of Russia bears great losses due to the lack of equipment for working on soils with low bearing capacity, which leads to the fact that harvesting of winter crops lasts more than 40 days, losses reach 42%. In a rainy year, the number of harvesting and transport equipment is increasing, the machines cannot enter the field and are idle. To increase the efficiency of agriculture, it is necessary to develop technological means for performing transportation and technological processes in adverse weather conditions. A number of agricultural crops, such as soy and rice, are grown using paddy fields, which makes it difficult to harvest crops from harvesters. During application of fertilizers, about 40% of the soil surface is compacted by wheels. Sealing of soil promotes formation of large and dense blocks during plowing, which worsen the conditions for normal plant growth. At present, none of commercially produced vehicles used in agriculture meets the requirements of GOST 26955-86.
Izvestiya MGTU MAMI. 2017;11(4):10-16
10-16
Dependence of durability and wear resistance on forcing and inaccuracies in ICE production
摘要
In this paper, the dependence of durability and wear resistance of parts on forcing and technical capabilities of the ICE production is analyzed. The development of engine building characterizes acceleration of ICE. Errors include a gap and correspondence of micro- and macrogeometry of the friction surfaces of the parts to their optimal, attained parameters. To ensure the operability, preservation and improvement of durability and wear resistance of parts, when forcing, the errors decrease. The purpose of the study is to evaluate the durability and wear resistance of parts from the technical capabilities of engine building, caused by design and production errors and the level of ICE forcing. The relationship between forcing, production and reliability is analyzed by the dynamics of development of automotive ICEs, empirical and predicted durability data and wear resistance of the crank mechanism and cylinder-piston group. The proportionality coefficient and the theoretical error of design and production of internal combustion engine for GAZ and ZMZ engines are being calculated. With modernization of production and reduction of errors, the technical characteristics of both an engine and a vehicle are improving. The connection between the engine and the car is given. Dependences of design and production errors and wear rates of the details of the crank mechanism and the cylinder-piston group on the forced internal combustion engine are derived. It is determined that with increase in compression ratio and the speed of a crankshaft, the wear rate decreases faster than the errors. This is due to the influence of errors on the properties of tribo-coupling, motor and car, the coordinated development of which provides increased growth of durability and wear resistance of parts.
Izvestiya MGTU MAMI. 2017;11(4):17-21
17-21
Load distribution by zones of frame sub-constructions of D2 class buggy racing car
摘要
In this paper, the authors consider the loading of the buggy car system under the most typical loading modes: the mode of approach of the front wheel to the obstacle, the mode of the rear wheel approach to the obstacle, the mode of diagonal loading, as well as the mode of twisting the frame around the longitudinal axis. For the convenience of analysis, the frame of the buggy car is divided into substructures, which, in turn, are divided into zones. For each of the zones of each sub-structure, the bar graph shows the proportion of the perceived load for each type of loading. The presented graphs make it easy to analyze overloaded and underloaded areas. For example, the rods of the upper zone of the rear subframe take a very small load, given the proportion of their volume. The reverse situation is observed in the sidewall region: in this zone much lower load is accounted for by a much smaller volume of material. At the same time, the areas of the floor and the middle perceive a load share, consistent with its volume fraction, which can be considered the optimal indicator of load distribution by volume. In this connection, it is important to note that the presented diagrams of the distribution of medium stresses over zones of substructures can be used as a starting point for optimizing of existing or for developing of such structures “from scratch”. Calculation of the load applied to the substructure was carried out by summing the average stresses on the elements constituting the considered subconstruction. In addition, with the help of the appropriate coefficient, an estimate was made to the correspondence of the proportion of the volume of the zone of a particular subconstruction to the proportion of the load applied to it. This information can then be used to optimize the design or used as a starting point for the design of similar structures. All the presented calculations were performed in the SolidWorks software using the finite element method.
Izvestiya MGTU MAMI. 2017;11(4):22-31
22-31
A crane-manipulator transfer position impact on a chassis loadings of a base vehicle
摘要
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.
Izvestiya MGTU MAMI. 2017;11(4):32-38
32-38
Speed characteristics of automobile diesel engine operating on natural gas
摘要
The article presents the graphs of the D-245.7 diesel engine's high-speed characteristics during gas-diesel operation. One of the ways to improve the efficiency of road transport is now to convert vehicle engines into alternative, cheaper fuels. Among various alternative fuels, natural gas is very attractive. If the diesel engine is to be converted to natural gas, then the implementation of the gas-diesel process will be the best method of transfer. There is not enough information in the literature on this issue, so research on this topic is relevant. In the Vyatka State Agricultural Academy research was carried out on the transfer of diesel D-245.7 to the gas-diesel process, the parameters of the combustion process, heat release characteristics, and effective indicators were determined. Work on the gas-diesel process leads to increase in the values of the parameters of the combustion process and the characteristics of heat release in the cylinder of the diesel engine. At the same time, thermal and mechanical loads increase slightly. In the initial periods of combustion in the cylinder, the speed and the value of the active heat release increase. This change indicates that combustion takes place by a three-dimensional mechanism. On the gas-diesel process, as compared to the diesel process, the hourly air consumption decreases, the temperature of the exhaust gases decreases, the boost pressure decreases, the effective efficiency decreases slightly, but the power and torque do not decrease. On the basis of the research, the following conclusions are drawn: 1) during the transition to the gas-diesel process, the pressure, the temperature in the cylinder, the rate of pressure increase rises, but the maximum values of these parameters do not exceed the permissible limits of diesel engines; 2) in the gas-diesel process, combustion in the cylinder occurs by a volumetric mechanism, most of the fuel burns in the rapid combustion phase; 3) the engine power parameters at the gas-diesel process in the entire speed range fully correspond to the diesel process; 4) when the diesel engine operates on an external high-speed characteristic on a gas-diesel process compared to a diesel process, a reduction of diesel fuel consumption by at least 83 % is achieved by replacing it with natural gas.
Izvestiya MGTU MAMI. 2017;11(4):39-45
39-45
Improvement of design of water evaporative air coolers in tractor cabins
摘要
For mobile objects, at the moment, foreign companies supply for Russia a wide range of air conditioning devices based in on the refrigerant refrigerant (freon) refrigerators. They are designed for use in fundamentally different from our climatic conditions, characterized by a relatively short warm period of the year, which should be taken into account when choosing the operating modes and composition of the functional parts of air conditioning units. Two variants of the design of two-stage water-evaporative air coolers made according to a separate scheme are proposed, where as a first (main) unit intended for air conditioning, a block is used that contains a successively placed water-air heat exchanger and a water-sprayed nozzle, and as a second (auxiliary) unit, intended for the preparation of cold water supplied to said water-air heat exchanger of the first unit, a cooling tower is used, containing in one variant irrigated only nozzle, and in the second variant - unit, similar to the air conditioning unit. Comparison of the IKPV and IRKV with the pilot KPO and RKV (T02), as well as with the coolant conditioner, shows that they are almost as cool as the experimental ones, having a significantly lower mass at acceptable overall dimensions of the roof unit and have the possibility of additional “wer” cleaning it from fine dust and gaseous impurities; basing the design of the proposed coolers on the units used in the normalization of the microclimate makes it possible to create, if necessary, the modification of IKPV and IRKV of various capacities; in the climatic conditions of Russia, which do not require dehumidification of conditioned air, innovative coolers are comparable by the condition of providing in the tractor cabs normalized parameters of the microclimate with refrigerant air conditioning devices, significantly exceeding them in terms of energy saving. Their introduction in areas with dry hot climate can make an alternative to cold-air conditioners, which they significantly exceed in terms of energy saving.
Izvestiya MGTU MAMI. 2017;11(4):46-56
46-56
Determination of the geometric shape of the air collector for supplying thermal energy to the heating system of electric bus batteries
摘要
Operation of electric buses in the winter climatic conditions of Russia is associated with the need to maintain positive temperatures of battery cells of the traction battery, taking into account the maximum available energy at battery temperature plus 20 ... 25 ° C. When operating battery cells that have negative temperatures, the energy of the batteries decreases by 20 ... 25%. The average temperature in the central part of Russia ranges from minus 18 ° C to plus 25 ° C. To ensure the battery operation in the above-mentioned temperature ranges, a thermostating system is installed. Depending on the operating conditions, these systems are performed both liquid and air. For air heating and cooling of the battery, a self-contained air heater is used as a heat source: a generator of heated air gases, and for cooling - supply and exhaust fans. Heated air passes through the collector from the auxiliary heater to the inlet ventilation holes. The geometric shape of the collector affects the flow rates of the air streams blown from the four outlets. Uneven consumption causes improper heating of the battery, which in turn leads to a charge imbalance between the individual battery packs and a decrease in battery capacity. The objective of the study is to determine the geometric shape of the air manifold, which provides equal heat flow through the outlet openings. The solution of this problem was performed by iterative calculations of air flows in various geometric forms of the collector in ANSYS CFX software. The results of calculation of air collectors intended for heating and ventilation of electric bus power batteries are presented in the article. The optimal shape, which ensures an equal flow of heat energy through the outlet holes, is determined.
Izvestiya MGTU MAMI. 2017;11(4):57-62
57-62
Absorption of gasoline vapors in automobile adsorber with a carbon filter
摘要
Modification of the component composition of gasoline, associated with the use of spirits and ethers (oxygenates) in modern fuels, as well as an increased content of combustible aromatic hydrocarbons may influence the dynamic activity of the coal filter. Therefore, the absorption of gasoline vapors with activated carbon (a coal filter) has been studied. The subjects of the study were samples of gasoline RON 95, RON 98, purchased at different times at gas stations in Russia and Spain. To carry out the tests a carbon filter (activated carbon) of the adsorber of the CITROEN C4 was used. Before filling the sorbent in a dynamic tube, it was regenerated, consisted of heating the coal to temperatures of 250 ... 3000С and forcing it to shake through the container with air material. Experiments on the absorption of gasoline vapors were carried out on a plant consisting of a rotameter, a Drexler bottle, a pressure stabilizer, and a dynamic tube. It has been established that, unlike other samples, two fuel samples have certain features that manifest themselves, in particular, in the values of the boiling temperature, in the value of the octane number, in the acidity parameters and in the remainder in the flask. Activated carbon has a higher adsorption and retention capacity with respect to the components of these gasolines. It is shown that this ability is a reflection of the increased content in the fuel of organic compounds with a higher molecular mass. Such substances include aromatic hydrocarbons and series of compounds containing polar substituents, for example methyl tert-butyl ether.
Izvestiya MGTU MAMI. 2017;11(4):63-69
63-69
Efficiency of application of direct-drive circuit for improvement of starting characteristics of gas turbine engine
摘要
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).
Izvestiya MGTU MAMI. 2017;11(4):70-80
70-80
Comparison of traction and longevity of caterpillar driving machines of agricultural tractors
摘要
The results of tests of various types of caterpillars on the tractor VT-150 on the evaluation of traction indicators, as well as sealing effect on the soil are presented. It is established that the tractor BT-150 with rubber-reinforced caterpillars in the zone of nominal traction effort of 36 ... 45 kN for tractors of class 3 develops the maximum traction power of 90.5 kW at a speed of 8.1 km / h, tractive effort of 40.2 kN and slipping 5, 1%, which is at the level of the corresponding indicators of the tractor with metal caterpillars with open metal joint. An assessment of the parameters of the effect of propulsors with different types of caterpillars on soil was carried out at the North Caucasus Experimental Station of the Krasnodar Research Institute of Agriculture of the Russian Agricultural Academy of the Russian Federation in an indoor sand channel. As a result, it is established that rubber-reinforced caterpillars ensure the operation of the tractor with soil moisture up to 0.7 НВ in the spring period and up to 0.9 НВ in the summer-autumn period. The analysis of the test results of the VT-150 tractor with various caterpillar designs showed that the use of rubber-reinforced caterpillars on the machine ensures: equality of traction parameters, including efficiency, machines on rubber-reinforced caterpillars and on metal caterpillars with open metal joint in the zone of nominal tractive effort for tractors of Class 3; the possibility of the machine working the field in conditions of high humidity; the ability of the machine to travel on roads with hard and advanced coatings without destroying them in comparison with metal caterpillars with open metal joint. It is shown that caterpillars with rubber-reinforced caterpillars have advantages in durability in comparison with metal caterpillars with open metal joint both on tractors and on combines.
Izvestiya MGTU MAMI. 2017;11(4):81-88
81-88
The new standard on the administrative aspect of registration changes in the design of the vehicle
摘要
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.
Izvestiya MGTU MAMI. 2017;11(4):89-99
89-99