Traction Performance Research Articles

GENERALIZED TRACTION INDICATORS OF AGRICULTURAL TRACTORS

In 1972 G.G. Kolobov and A.P. Parfenov published the monograph «Traction characteristics of tractors». The monograph generalized numerous results of field tests of domestic wheeled and caterpillar tractors of that time, conducted by machine testing stations in various soil and climatic zones of the USSR. This had an impact on formulation and study of the issue of determining of tractors slippage, and in general, the study of their traction characteristics. Averaging of the experimental data was carried out according to the formulas and coefficients developed by the authors of the monograph. The obtained dependencies, hereinafter referred to as traction characteristics of tractors, establish the dependence of the coefficient of usable traction (specific traction force on the hook) on the slipping of tractors of various types on different soils. By now, the concept of the role of the studies in research of the interaction of a wheel and track with the surface has changed. The standards have been introduced to limit slipping of agricultural tractors, considering the negative impact of their propulsors on the soil. There is a need to clarify the terminology used earlier in order to unify the same meaning terms used in different, but related technical disciplines. Objectives of work are: rethinking of previous research results and assessing their relevance; distinction between the physical meaning and concepts of the traction coefficient and the coefficient of usable traction (specific traction force on the hook); determination of traction capabilities of wheeled and caterpillar tractors on natural agrotechnical and asphalt-concrete surfaces, considering current slippage limitations. It was proposed for the purposes of engineering calculations in assessing traction performance of tractors to use as a traction coefficient of various propulsors its value corresponding to the maximum slipping on the appropriate agro-technical background or dry concrete. It is also found that the limitations on slipping of tractors on metal caterpillars are overstated on all soil backgrounds, since they rather characterize the «stop» mode of the tractor, than the beginning of the unstable operation of the engine. The parameters of traction characteristics of 4x4 wheeled tractors require correction based on statistical replenishment with the initial data on traction tests of such tractors having a layout that considers the increased role of the front drive axle in creating the tractor pulling power. For 4x2 tractors traction characteristics are at the same time characteristics of traction performance of individual driving wheels (tires). Therefore, having such data on all available driving tires of different dimensions, it is possible, at the development stage, to determine traction properties of newly created different variants of machines, including all-wheel drive.

A Stationery Loading Unit for Measuring Farm Tractors Power in PTO

The torque and power of a tractor are two important decision making factors when buying an agricultural tractor. These factors are generally extracted through PTO tractor testing. Such testing is accomplished using a device called dynamometer. Since commercial dynamometers are expensive, research efforts are encouraged to develop similar dynamometer for tractor tests. The aim of this study was to fabricate and adapt an automobile brake system to become a PTO shaft brake loading system for measuring torque and power. A commercial torque transducer was fixed to the tractor PTO for both toque and rotational speed measurements. Tests were performed on a Helwan 35 IMT tractor with 26.12 kW of power. The laboratory demonstration test showed that the measurement of torque magnitude at PTO of the tractor was satisfactory. The results were compared to those obtained through loading the same tractor with a shop AW commercial dynamometer and the relative error between the data sets was -2.59%. A t–test showed no significant differences in the averages of power. Considering the results of this study, the PTO shaft brake loading system can feasibly applied to tractor performance evaluation.

Effect of Jatrophaand Ethanol Biofuel Blending on Performance of Agricultural Diesel Engine Tractors - Sudan

This study was carried out to investigate the effect of fuel type ( pure diesel, blending 10% of Jatropha oil with diesel (J10%), blending 14% of Jatropha oil with blending (J14%),blending 10% of ethanol with diesel (E10%), blending 14% of ethanol with diesel (E14%), blending 10% of Jatropha oil and 10% of ethanol with diesel (J10%, E10%) and blending 14% of Jatropha oil and 14% of ethanol with diesel (J14%, E14%)), on exhaust gases, engine speed, implement draft and power requirement and fuel consumption. The results showed that, Blending J14%, E14% recorded the highest rate of fuel consumption as 4.60 l/h compared with pure diesel which recorded 3.90 l/h. Pure diesel fuel recorded the lowest engine speed of 2174 rpm, while the fuel blends recorded engine speed in the range of 2529 – 2583 rpm. The fuel blend J14% recorded the lowest ppm of CO and of NO2.The J10%, E14% and J10% with E10% blending’s recorded the lowest SO2 as zero ppm. Pure diesel recorded the highest power requirement of 6.81 kW while J14% recorded the lowest power of 5.32 kW. Ethanol blending’s showed higher power than Jatropha blending by 19.7%. Statistical analysis showed that, the effect of fuel blending on draft and power, gases exhausted, engine speed and fuel consumption were not significant.

Effect of lug angles of rigid wheel on the tractive performance on hard soil ter

Effect of lug angles of rigid wheel on the tractive performance on hard soil ter

Model Railway Traction Performance Measurements and Analysis

The purpose of this paper is to introduce measurements and analysis of a 1:8 scale model railroad in order to provide the possibility to use modern locomotive design methods in this application. Tractive force and vehicle speed are necessary for this analysis and therefore a measuring train car has been developed. On-board strain gage and a magnetic encoder are used to obtain the necessary data. Therefore a part of this paper is devoted to describing the usage of these sensors. Obtained data is processed, analyzed and also compared to a full scale railroad.

The Concept of Converted Electric Vehicle with Advanced Traction and Dynamic Performance and Environmental Safety Indicators: Theoretical Basis

Objectives: To produce effective technical solutions on the structure, composition and characteristics of propulsion systems of Electric Vehicles (EV) to be converted on the basis of conventional vehicles. Methods/Statistical analysis:The success of this work can be determined only in the framework of the full technological cycle for the conversion of conventional vehicles in electric vehicles. The conversion process shall be carried out according to a specialized procedure and be accompanied by a necessary implementation of specific criteria and guidelines to follow that will allow for the development of a truly effective in relation to consumer and performance properties of the electric vehicle. Findings: This article presents the results of the development of scientifically based concept for the design of the converted electric vehicles, including the methodology for calculating the key characteristics of the components of electrical traction systems,optimization criteria of operating characteristics of electric vehicles as well as the conversion principles of conversion.The aspects of the energy efficiency of propulsion systems are reviewed, while using multi-parameter characteristics, a qualitative analysis is made, including comparison of the optimal operating conditions of Internal Combustion Engines(ICE) of conventional vehicles and electric traction drive. The basic phases of conversion of vehicles to electric vehicles are laid down, which are defined in the framework of the basic phases and the necessary process operations. The results can serve as guidance material in the development of electric vehicles and assessment of electric vehicle performance at the design phase as well as contribute to a rational choice of propulsion system options at conversion. Improvements/Applications: The indices, dependences, principles and provisions presented here build the basis of the concept of full technological cycle for the conversion and can be used to assess the characteristics of the convertible electric vehicle at the design stage, as well as contribute to a rational choice of powertrain parameters when converting.

Power performance of farm tractor in field operations

Power performance of farm tractor in field operations

A visual basic program and instrumentation system for power and energy mapping of tractor implement

A program in visual basic software was developed for predicting tractor implement performance and energy mapping of tractor implement combination. A simple and complete instrumentation system for evaluation of tractor performance under actual field condition is discussed. The instrumentation system of tractor was tested under actual field condition for validation of the developed software, and found good results. The software was developed by considering various traction models, fuel consumption models and draft models to fit for most commonly used agricultural tractor implement combinations. The developed software is user friendly and efficient in predicting. This could help the researchers and engineers for power and energy mapping of new tractor and implement models.

TOWARD REPLACEMENT OF PETROLEUM OILS BY MODIFIED SOYBEAN OILS IN ELASTOMERS

ABSTRACT Precipitated silica- and carbon black (CB)-filled styrene-butadiene rubber (SBR) compounds and vulcanizates containing naphthenic oil (NO), soybean oil (SO), and modified soybean oil (MSO) were studied. Gel fraction; crosslink density; bound rubber fraction; curing behavior; and thermal, mechanical, and dynamic properties were compared. Interaction between SO, MSO, and silane coupling agent was also studied. It was shown that the incorporation of SO and MSO had similar effects in both silica- and CB-filled SBR compounds and vulcanizates. SO and MSO were found to consume curatives leading to a lower crosslink density and improved thermal stability of compounds and vulcanizates. In comparison with NO, MSO was found to increase the elongation at break and tensile strength, and the values of tan δ at 10 °C and 60 °C predict an increase of the wet traction performance and the rolling resistance to decrease the modulus and abrasion resistance. After adjusting the recipe, the modulus and abrasion resistance of the silica- and CB-filled SBR/MSO vulcanizates were tremendously increased, and the silica-filled SBR/MSO vulcanizates exhibited a better wet traction performance, a lower rolling resistance, and a better abrasion resistance simultaneously than the silica-filled SBR/NO vulcanizate.

Improvement of traction performance and off-road mobility for a vehicle with four individual electric motors: Driving over icy road

To control speed and wheel slip for severe conditions of tire-surface interaction is a challenging task in the design of traction control system for electric vehicles with off-road capability. In this regard, the present paper focuses on a specific traction control for an electric vehicle with four individual in-wheel motors over icy road. The study demonstrates that a proper integration of the speed controller and wheel slip controller can essentially improve the mobility of the vehicle in the cases of acceleration and slope climbing. The paper discusses relevant case studies with particular attention given to the system architecture (sliding mode and PID control methods), extremum-seeking algorithm for maximum tire-road friction and corresponding slip value, and experimental validation of the tire model used in the controller with the help of the Terramechanics Rig in the Advanced Vehicle Dynamics Laboratory (AVDL) at Virginia Polytechnic Institute and State University.

Straight Vegetable Oil as a Replacement Fuel for Diesel: Comparing Tractor Performance in Stationary and Field Tests

Straight Vegetable Oil as a Replacement Fuel for Diesel: Comparing Tractor Performance in Stationary and Field Tests

Real-Time Optimal Control of a 3-Phase PMSM in 2-Phase Degraded Mode

This paper aims to optimize real-time control for the degraded mode of a fault-tolerant power architecture but not the fault detection and isolation procedure itself. Such power architecture is dedicated to electric vehicles in which it performs the three following essential functions: traction, battery charging, and electric-grid assistance. For safety reasons, in the degraded mode, power control is limited to the traction mode. Thus, for a given torque, the proposed innovative strategy uses a novel current/voltage transform that leads to efficient real-time control of the torque. The key idea is to drive the current without a priori restrictions on its waveform, while minimizing Joule losses, i.e., the effective value of the current. It has been validated on a laboratory test bench. The studied system is based on a three-phase open-end-winding synchronous machine powered by an inverter with three full H-bridges. The last section of the paper analyzes the comparison between the classic sinusoidal current waveforms and the proposed sinusoidal current waveforms while operating on the two remaining motor phases. It results in a 14% increase of the torque produced by the permanent-magnet machine under test and a 14% decrease of the global system losses in traction mode. As a result, the new control strategy enhances traction performance in degraded mode and increases electric-vehicle autonomy in a postfailure condition.

Influence of the tyre characteristics on the tractor performance

La presion, el patinaje y el tipo de construccion del neumatico son factores significativos para el desempeno del tractor. Este trabajo tiene como objetivo recoger informaciones sobre la influencia de diferentes lastrajes, presiones, construcciones de neumatico y diferentes superficies en el desempeno del tractor. La utilizacion de ciertas de presiones de inflado, y ciertos niveles de lastrajes posibilita obtener un mayor rendimiento del tractor, reduciendo perdidas de energia por la resistencia al rodamiento, reduciendo tambien perdida de traccion, patinaje y consumo de combustible. La interaccion entre un neumatico y el suelo varia conforme la superficie de rodamiento, impactando en el rendimiento operacional de los tractores. Se puede concluir que el desempeno de un tractor agricola depende de condiciones como presion en los neumaticos, tipos de construccion de los neumaticos, patinaje y lastraje. El uso de neumaticos con mayores presiones acarrea mayor compactacion del suelo.

Tractor traction performance simulation on differently textured soils and validation: A basic study to make traction and energy requirements accessible to the practice

Several models exist to simulate traction performance of a tractor, however, for most of them a proper experimental validation is missing. Moreover, their possible application for a practical use in a wide range of vehicles, equipment and soil configurations has never been further developed. This study examines a semi-empirical model of soil-tyre interaction, adapted to simulate the traction performance of mechanical front wheel drive tractors, taking into account not only mechanical soil and tyre parameters and static vehicle load but also the multi-pass effect, the load transfer effect, and the theoretical speed ratio between front and rear axles. This model simulates drawbar pull, traction coefficient, traction efficiency, and motion resistance as a function of slip, wheel load, tyre size and pressure. Several traction tests were performed on four Swiss agricultural soils of different type (clay, clay loam, silty loam, and loamy sand) in order to validate the model experimentally. Three tractors of widely ranging power (from 40 to 132kW) and weight (from 24 to 68kN) were used. Tractor configurations were varied by changing tyre pressure and tractor weight. Slip normally ranged between 5 and 30%. In most of the cases the model simulated drawbar pull as well as its variations due to changes in tyre pressure, wheel load, and soil strength reliably for practical purposes. Only when high wheel load was combined with low inflation pressure the model did not give suitable results due to an overestimation of the rolling radius. Based on the presented model, a convenient Excel-application called TASCV3.0 was developed for the practice. Such a practical computer-tool supports farmers in decision making concerning the tractor configuration, oriented to save fuel during agricultural operations.

Экспериментальные исследования сопротивления почвогрунта при вдавливании конического индентора

This article informs us about testing the theoretical dependence to calculate cone index re-garding the soil deformation module. Common methods of calculation tractive performance of wheeled mover do not allow to analyze the influence of the geometric parameters of wheeled mover,inner tire pressure, slip ratio, wheel load, as well as the physical and mechanical properties of forest soil on rolling resistance, net thrust and drawbar pull coefficient in complex.

Performance evaluation of a wire mesh wheel on deformable terrains

Because of the unique lunar environment, a suitable wheel for lunar rover decides the rover’s trafficability on deformable terrains. The wire mesh wheel (hereinafter referred to as WMW) has the advantages of light weight and superior stability, been widely adopted for lunar rovers. But a comprehensive research on performance of WMW on deformable terrains has not been conduct. This paper would provide particular study on a type WMW, including quasi-static pressure-sinkage test and driving performance. A novel pressure-sinkage model for the WMW on deformable soils was presented. In order to investigate the sinkage characteristics of the WMW, tests were performed using a single-wheel testbed for the WMW with different loads and velocities. The effects of load and velocity on sinkage were analyzed, and the relationship between real and apparent sinkage was presented. The research on traction performance of WMW under different slip ratios (0.1–0.6) was also conducted, contrast tests were proceed by using a normal cylindrical wheel (hereinafter referred to as CW). The traction performance of WMW is analyzed using performance indices including wheel sinkage, drawbar pull, driving torque, and tractive efficiency. The experimental results and conclusions are useful for optimal WMW design and improvement/verification of wheel–soil interaction mechanics model.

Multi-Condition Contact Stress Analysis of High Speed Train Helical Gear

Taking traction helical gear of CRH380A high speed train for example, not only analyzing the meshing process characters of the high speed train helical gear and the tractive performance curve, but also using Pro/E to complete a three-dimensional model, combining with ANSYS workbench, helical gear contact finite element model is built in start-up, continuous and high speed conditions. A meshing period equivalent stress and contact pressure distributions of gear tooth surface are obtained by solving the model. And so are the changing regularity of gear contact state and stress on the meshing process. The result shows that based on ANSYS workbench, dynamic contact stress analysis about traction helical gear of high speed train can reflect the realistic contact stress state among the meshing process. It provides some certain references and foundations to calculate the gear’s strength analysis and modification design.

Effect of grouser height on tractive performance of tracked mining vehicle

The aim of this study is to establish a single track shoe with grouser driving model to optimize the track structural parameters and improve the tractive performance of the tracked mining vehicle on soft sediments. The calculation formula of each component force and total driving force about grouser height was obtained through theoretical analysis. The basic parameters and the relationship of mechanical properties for computer simulation were also obtained by the testing experiment using soil simulation whose main physical and mechanical properties are close to the deep-sea sediments. The computer simulation results show that the total driving force of the track improved rapidly with the increases of the grouser height and the slip rate. It keeps rising until it reaches a maximum value. And then it will maintain a steady value when the slip rate exceeds 40 %. The total driving force also improved with the increase of the ratio (slip rate/grouser height). When the grouser height is in the range of 0–15 cm, the total driving force keeps increasing gradually with the increase of the slip rate until it reached the stable state. When the grouser height is in the range of 15–30 cm, the total driving force keeps increasing to a maximum value rapidly with the increasing of slip rate first, and then keeps decreasing gradually. The greater the increase of grouser height, the faster the decrease of the total driving force.

Soil Tillage Systems and Wheat Yield under Climate Change Scenarios

In this study, the effects of three different main preparatory tillage operations: ploughing at 0.4 m (P40) and 0.20 m (P20) depth and harrowing at 0.20 m depth (MT) were investigated. The tillage operations were carried out at two different times, as the soil water content increased over time from rainfall: (low, 58% (LH) and high, 80% (HH) of field capacity). Results obtained from the soil monitoring carried out before and after tillage showed high values of soil strength in terms of Penetration resistance and shear strength particularly in deeper soil layers at lower water content. During tillage, fossil-fuel energy requirements for P40 LH and P20 LH were 25% and 35% higher, respectively, with respect to the HH treatments and tractor slip was very high (P40 LH = 32.4%) with respect to the P40 HH treatment (16%). Soil water content significantly influenced tractor performance during soil ploughing at 0.40 m depth but no effect was observed for the MT treatment. The highly significant linear relations between grain yield and soil penetration resistance highlight how soil strength may be good indicator of soil productivity. We conclude that ploughing soil to a 0.20 m depth or harrowing soil to a 0.20 m depth is suitable for this type of soil under climate change scenarios.

Numerical analysis of lug effects on tractive performance of off-road wheel by DEM

This paper presents the lug effects of off-road wheel in terms of lugs’ height, type, intersection and central angle. To improve the tractive performance of transport vehicles and equipments operating on dry sands nearshore, this paper numerically presents the wheel–sand interaction by the discrete element method (DEM), which is better dynamically accurate than FEM in the study of incompact terrain-like sands. According to the physical properties presented by the triaxial test, the appropriate parameters are selected to establish and verify the simulation model of the sand sample. On that basis, numerical traction tests are orthogonally carried out to analyze the different lug effects on tractive performance. It is concluded from the analysis that the intersection of lugs has no effect on tractive performance. Lugged wheel shows the best tractive performance, while the central angle of lugs reaches 24°. Both the height and type of lugs can improve the drawbar pull; the former may increase the tractive efficiency under good road conditions with low slip, while the latter is capable of influencing the efficiency under bad road conditions with high slip.