No 3 (2017)

Articles

THE STUDY OF POSSIBILITIES FOR REDUCING FUEL CONSUMPTION FOR NATURAL GAS ENGINE BASED ON DIESEL AT IDLE SPEED

Apelinskiy D.V., Gusarov V.V., Fomin V.M.

Abstract

Diesel-to-natural gas engine conversion is an important economic task. In this modification the gas engine has some fundamental differences from the diesel: forced ignition is replaced by Compression ignition; as a rule, external mixture formation instead internal mixture formation; the quantitative load control using throttle - instead quality load control. The latter is one of the main reasons for the deterioration of the fuel economy of the gas engine especially at low loads, because of the significant increase in pumping losses when reducing the load by throttling. The greatest value of such losses is on the idle speed. The authors considered the possibility of increasing the efficiency of the gas modification due to the implementation of the Miller cycle, where the load reduction is achieved by variable valve timing - mainly the valve Duration and intake valve closing angle. In this case, the load reduction is achieved without the use of throttling the fuel / air mixture. The analysis is performed using a calculation method, which was developed a special program takes into account the main physical processes of the gas engine at low operating conditions. The authors considered several options for improving fuel economy at engine low load operation for the engine KAMAZ-820.74-300, including the possibility of using lean air fuel mixture, increasing the compression ratio, load management using changing valve timing. The authors defined the values of temperature and pressure at characteristic points of the pressure volume diagram, and the values of indicated thermal efficiency of an engine, fuel consumption and other parameters for the five variants of idling. The authors presented the calculated pressure volume diagrams of a Miller cycle at idle. The authors have shown the best option, where possible fuel economy improvement at idle is 25 % compared to the base engine.
Tractors and Agricultural Machinery. 2017;(3):3-9
pages 3-9 views

VARIANTS OF TWO-COUPLE GEAR SHIFTING ORGANIZATION ON TRACTORS

Alendeev E.M., Kryuchkov V.A.

Abstract

In recent years, we can see trend of increasing tractor transport and operating speeds, which is also accompanied by increasing of gears number in manual transmissions. Increasing of gears number in Powershift transmissions is achieved by using in gearbox construction a few operating ranges. Every range and every gear of such gearboxes are switched by separate friction clutch that gives opportunity to organize gear shifting without power interruption in all tractor speed range. However, such technical solutions lead to appearing gear shifting, requiring of pressure control in four friction clutches at once (two-couple gear shifting): two gear clutches and two range clutches. This article is dedicated to the questions of two-couple gear shifting process organization in agricultural tractor gearboxes. These questions had required to design mathematical model of this process in Matlab Simulink software. Modelling was implemented under conditions that transmission control system and engine control system had opportunity of data exchange between themselves, which allowed to define the load torque value, acting on engine, and to control engine speed. A few variants of two-couple gear shifting up and down organization were modelled and compared in parameters of clutch wear. The modelling results show that simultaneous high gear clutch and high range clutch slipping during gear shifting gives the same oncoming clutches accelerated synchronization as during gear shifting with engine control.
Tractors and Agricultural Machinery. 2017;(3):10-18
pages 10-18 views

WHEEL ROLLING RADIUS WITH ELASTIC TIRE

Kopotilov V.I.

Abstract

The rolling radius of the wheel is considered as a result of normal and circumferential deformations of its pneumatic tire, caused respectively by the normal load and the torque applied to the wheel. Consideration of the normal deflection of the tire enabled the value of the rolling radius of the driven wheel to be represented as a function of the axial load per wheel and the radial rigidity of the tire. To assess the adequacy of the developed model, the example of the 26°-2° tire used in trucks is used to calculate the kinematic radius for different values of the normal load. Analysis of the calculation results shows that the kinematic radius of the driven wheel decreases linearly with increasing normal load. This is in good agreement with the results of previous experimental studies. When considering the action of torque, it is considered that it causes a tangential (circumferential) deformation of the tire, i.e. its twisting, as a result of which the rim of the wheel makes a certain turn relative to its periphery. In this case, this rotation of the rim is not accompanied by a longitudinal displacement of the axis of rotation of the wheel itself. Since the torque breaks the single-valued relationship between the linear and angular velocity of the wheel, this is reflected in the kinematic radius of the wheel. Based on the dependence of the twist angle and torque, an analytical dependence of the rolling radius on the algebraic magnitude of the torque and the torsional rigidity of the tire is established. Calculation of the rolling radius of the wheel, carried out according to this formula, shows that when the torque is applied, a linear decrease in the rolling radius occurs, and when the braking torque is applied, on the contrary, its linear increase is shown. Such a change in the rolling radius completely agrees with the results of experimental studies of various types of pneumatic tires.
Tractors and Agricultural Machinery. 2017;(3):19-23
pages 19-23 views

DESIGN METHOD OF PIN ENGAGEMENT DRIVE SPROCKETSWITH RUBBER-REINFORCED TRACKS OF TRACTION AND TRANSPORTATION VEHICLES

Fedotkin R.S., Kryuchkov V.A., Beynenson V.D., Parfenov V.L.

Abstract

Nowadays rubber-reinforced tracks found wide application on different purpose traction and transportation vehicles due to well-known advantages, including possibility of their installation instead of metal linked tracks without significant modernization of undercarriages structures. The operational experience of vehicles with rubber-reinforced tracks shows that their construction differences in comparison with metal tracks provide increased loading to crawler outline, especially to drive sprockets. It shows on necessity of individual drive sprockets design for rubber-reinforced tracks. Special methods for this are absent and traditional methods intended for metal tracks do not provide reliability and efficiency of track engagement. The article contains the special designed method of pin engagement drive sprockets with rubber-reinforced tracks engineering. Practically established that rubber-reinforced track bending is going through the broken line in conditional joints and the engagement element with the drive sprocket tooth is spool of inset element with the part of reinforce lay. All the necessary analytical dependences for drive sprockets design and calculation are shown. The optimal values of contact angle for real constructions of rubber-reinforced tracks, when the normal teeth form is provided; analytical dependences of kinematic pitch circle and bottom circle radiuses for different variations of conditional joints are determined. Boundary conditions for optimal values determination of drive sprockets width and thickness and also their heads radius are accounted. The efficient options of drive sprockets teeth profile curves plotting are shown. The developed design method of pin engagement drive sprockets with rubber-reinforced is based on typical methods for metal tracks and takes into account structural features of rubber-reinforced tracks. It provides reliability and efficiency of track engagement and can be used in design process of traction and transportation vehicles undercarriages.
Tractors and Agricultural Machinery. 2017;(3):24-32
pages 24-32 views

BRAKE OF THE FRONT DRIVE WHEELS OF THE TRACTOR "BELARUS"

Mel'nikov A.S., Bilyk O.V., Choy K., Mel'nikov A.A.

Abstract

The increase in the energy saturation of the new models of tractors "Belarus", as well as the mass of towed trailers and agro-technological tools that are mounted with them, required an increase in the efficiency of the tractor braking system. The purpose of the study is to increase the efficiency of the braking system of the wheeled tractor "Belarus MTZ" by creating wheel brakes for the front axle with minimal changes in its standard design. The developed drum brake with hydraulic drive of the front drive wheels of the tractor "Belarus MTZ-1221" does not require significant changes in the standard design of the front axle of the MTZ tractor and is adaptive to the anti-lock system, which operates on the basis of measurement and analysis of force factors. The design of the developed brake mechanism allows its adaptation to the anti-lock system, which operates on the basis of measuring and analyzing the forces that arise in the contact of the wheels of the front axle of the tractor with the supporting surface. The braking effect of the tractor "Belarus MTZ-1221" is provided by additional use of its coupling weight, which falls on its front axle. A set of design documentation for the drum brake for the front driving wheels of the tractor "Belarus MTZ-1221" was developed. The use of an additional traction weight of the tractor due to the wheel brakes of the wheels of the front axle of the tractor "Belarus MTZ-1221" will increase the efficiency of its braking, as well as increase the competitiveness of wheeled tractors produced by the JSC "Minsk tractor works". Bench tests confirmed the possibility of braking the calculated moments corresponding to the weight load on the front axle of the tractor "Belarus MTZ-1221". Consequently, the developed brake mechanism will ensure effective use of the tractive weight of "Belarus MTZ-1221" tractor.
Tractors and Agricultural Machinery. 2017;(3):33-40
pages 33-40 views

THE ESTIMATION OF CONSTRUCTION AND PARAMETERS FOR CAREFUL LOADING OF CABBAGE HEADS BY MACHINE-HARVESTING

Alatyrev S.S., Cruchinkina I.S., Yurkin A.P., Alatyrev A.S.

Abstract

When cabbage is traditionally machine-cleaned, its heads are mechanically damaged to a considerable extent, which reduces their shelf life during storage. The bulk of the damage is attributed to the processes of shipment of the heads to the body of the vehicle in bulk and unloading it when laying cabbage for storage in the coats. In existing designs and well-known works, no practical solutions were found, which could be realized with maximum efficiency in harvesting cabbage. In this regard, the aim of the study is to substantiate the design and basic parameters of the device for the careful shipment of cabbage heads during machine harvesting. For this purpose, a new method for machine harvesting cabbage is proposed (patent RF 2554403), where, unlike the traditional method, the head is first shipped in a sparing mode on a flexible trough-shaped flooring installed on a special rack above the detachable containers in the body of the accompanying vehicle. Then the heads from the flooring are gently transferred to containers for subsequent storage in them. The efficiency of the use of the proposed device and the degree of reduction of head damage in the process of shipment depends on its design and correct justification of the parameters. The nature of the flow of the process of shipment of heads is essentially dependent on the type of sagging curve of the trough-like form of the flooring. For the purpose of substantiating the design and parameters of the device for careful shipment of cabbage heads during machine cleaning, a mathematical model of the construction is proposed, using which the necessary parameters of the proposed device are determined.
Tractors and Agricultural Machinery. 2017;(3):41-44
pages 41-44 views

FEASIBILITY OF THE GRANULAR FERTILIZER DISTRIBUTOR'S BLADE FORM

Shwartz A.A., Besedin B.P.

Abstract

Using fertilizers, in line with other agrotechnical activities, is one of the most important means for increasing soil fertility, as well as agricultural products performance. Domestic and foreign experience shows us that yield capacity can grow almost 1.5-fold due to fertilizers. Nowadays the surface type of using hard organic and mineral fertilizers by means of body spreaders is considered to be one of the simplest technically and most effective ways. Being the object of the research, the experimental mineral and organo-mineral granular fertilizers spreader is a van-type lowboy, equipped with a belt conveyor and a vertical rotor with a horizontal axis of rotation. In addition to load bearing characteristics, rotational movement of the operative parts in the casing of the rotary drum provides for air drag, which influences the trajectory of fertilizers flight. Pattern of fertilizer distribution, flight distance of fertilizer particles and horsepower input of the gear system depend on the design features of the operative parts of the pneumatic-mechanical rotor. The objective of the research is to define travel speed of fertilizer particles along vanes in case of constant fertilizer input with air drag in versions with radial position of vanes, bent backwards and forwards to some angle. The main research techniques are a graphical and analytical method and analysis of the component force which operates on the blade's surface. As for the drum with a diameter of 920 mm, at rotation frequency of 850 min-1, the best performance was shown by the through blade. They may reduce the friction force of the casing of rotor. Besides, they can concentrate fertilizers in the center of a blade, and achieve qualitative work of the fertilizer spreader, is ascertaining.
Tractors and Agricultural Machinery. 2017;(3):45-49
pages 45-49 views

THE CALCULATION OF THE DEPENDENT TOLERANCE ALIGNMENT REPAIR SHAFTS GEAR BOXES

Leonov O.A., Vergazova Y.G., Antonova U.Y.

Abstract

Distortion of the shape of the component parts leads to a decrease in the operational properties of these parts Thus, in movable joints the deviation of the component parts from the correct cylindrical shape leads to an inadequacy of its movements, rapid wear due to contact over a limited surface. In fixed joints, distortion of the shape leads to uneven tension in the joints, because of this, the strength of the joint, the tightness and the accuracy of the centering decrease. Distortion form also affects labor and assembly accuracy, increases the amount of trimming work affects the accuracy of basing of parts in the manufacture and control. Deviations in the location of surfaces from their nominal values are extremely detrimental to the reliability of the machines, causing additional static and dynamic loads in separate parts and joints, which leads to rapid wear and fatigue failure of the parts. Tolerances location or shape to be set for shafts or openings may be independent and dependent. Dependent location tolerances are set for the items, which are interfaced with the object at the same time on two or more surfaces, and for which the interchangeability requirements are reduced to ensure the collection, ie, connectivity details on all mating surfaces. Dependent tolerance indicated in the drawing or other technical documents value which may be greater than the value of which depends on the deviation of the actual size of the element and / or the base material of the maximum limit. On the example of the shaft of the unified reducer of the MOSSELMASH plant, under the designation H090.040, three variants of the assignment of the dependent tolerance of alignment are considered, which, on the one hand, allows to expand the capabilities of the technological equipment and reduce the cost of processing, and on the other hand, ensure the assembly of connections without fitting. For our example, the use of the third variant of the notation extends the alignment tolerance of the two shaft surfaces from 0.010 to 0.048 mm, which is not only economically feasible, but also allows the use of full interchangeability to be competently used.
Tractors and Agricultural Machinery. 2017;(3):50-53
pages 50-53 views

MATHEMATICAL MODELING OF THE CONTROLLED MOTION OF THE WHEELED MACHINE-TRACTOR UNIT

Poddubnyy V.I., Pavlyuk A.S., Poddubnaya M.L.

Abstract

A brief review of the systems of precise farming is given, problems of scientific and practical research are formulated to create a domestic system of accurate farming using autopilotation. The analysis of applied software used in the development and approbation of algorithms for controlling the movement of wheeled agricultural machines is carried out. The ideology of the development of mechatronic systems using the CAMeL-View application package is presented, a mechanical-mathematical model of the machine-tractor unit consisting of a wheeled tractor and a semi-mounted plow is described. The results of mathematical modeling of the movement of a machine-tractor unit at a speed of 2.5 m / s are presented using control based on the basic maneuvers of wheeled vehicles when the soil is processed to a depth of 0.24 m. The required slope angle of the tractor frame is defined as a linear combination of dependencies for changing the curvature of the trajectory, the direction of motion, the lateral displacement and the initial angle of rotation of the steered wheels. The analysis of the results allows to draw a conclusion about the rather good quality of the working movement of the arable unit, which indicates the efficiency of the proposed control algorithm. The program implementation of the control algorithm is proposed in the wheeled agricultural machines developed with the participation of authors of the electromechanical control system for the movement using satellite radio navigation systems GLONASS and GPS. With a real control of the movement of a wheeled agricultural machine, a significant deterioration in the quality of motion is caused by inaccurate determination of its current coordinates when using satellite GPS and GLONASS radio navigation systems. Accordingly, the level of lateral deviations of the working mechanisms of the agricultural machine will be higher than the motion obtained from the modeling results, using the proposed control algorithm. The final conclusion about the limits of applicability of the proposed control for various fieldwork will be made based on the results of field tests of the control system.
Tractors and Agricultural Machinery. 2017;(3):54-60
pages 54-60 views

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