Dependencies of the Lead of Front Driving Wheels on Different Tire Deformations for a MFWD Tractor

Janulevičius, Algirdas; Pupinis, Gediminas; Lukštas, Justas; Damanauskas, Vidas; Kurkauskas, Vaclovas

doi:10.3846/16484142.2015.1063084

Cited by 22 publications

(13 citation statements)

References 28 publications

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“…For the theoretical calculation of the optimal tractor wheel slippage it is important to know the attraction factor dependence on the size of the traction force and the vertical load on the tires and the tire pressure indicators as well. However, literature analysis [13][14][15][16][17][18][19] has shown that known tractor wheel slippage determination mathematical modules do not take into consideration the tire inflation pressure. The researchers Hinsburg, Parfenov and Swede have proposed an empirical model for prediction of the tractor slippage [18]:…”

Section: Introductionmentioning

confidence: 99%

Estimation of tractor wheel slippage with different tire pressures for 4wd and 2wd driving systems

Janulevičius

Juostas

Pupinis

2019

Engineering for Rural Development

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The wheel slippage of agricultural tractors is a critical parameter for fuel consumption and field performance. Optimally it should be in the range of 8-12 % and should not exceed 15 %. Therefore, during assembling agricultural units, it is not enough to consider the traction characteristics, but also the recommended value of the slippage must be followed. Of the available solutions to decrease the tractor driving wheel slippage is to decrease the air pressure in the tires and increase the additional mass (ballast weight) of the tractor, avoid tilling soil that is too wet or too dry and choose the right implement, tillage speed and depth. The wheels' slippage could be reduced with a traction control and other relevant tractor systems. Agricultural/field applications require tractors with 4WD or 2WD driving systems. Engaging the four-wheel drive, when using the tractor for tillage operations, also can decrease the wheel slippage. In any case, the fuel consumption must be taken into consideration. For the theoretical calculation of the optimal tractor wheel slippage it is important to know the attraction factor dependence on the size of the traction force and the vertical load on the tires and the tire pressure indicators as well. However, literature analysis shows that known tractor wheel slippage determination mathematical modules do not take into consideration the tire inflation pressure. The goal of this study is to investigate the tire air pressure influence on the driving wheel slippage, tractive force and the traction coefficient for 4WD and 2WD driving systems of the tractor. With help of mathematical equations the traction force and wheel slippage coefficient dependencies on the air pressure in tractor tires are calculated. As well, according to the research result data, the wheel slippage forecasting methodology based on the numerical evaluation of the tire inflation pressure for 4WD and 2WD driving systems of the tractor is provided.

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Section: Introductionmentioning

confidence: 99%

Estimation of tractor wheel slippage with different tire pressures for 4wd and 2wd driving systems

Janulevičius

Juostas

Pupinis

2019

Engineering for Rural Development

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“…Information sources state that in field work, MFWD tractors deliver the highest traction force when the front wheels' lead is 3…4%, and in transport operations, MFWD tractors deliver the highest traction force when the front wheels' lead is 1…2% (Andreev et al 2010;Janulevičius et al 2017;Molari et al 2012). In addition, it is known that the front wheels' lead improves dynamics of tractors in turning manoeuvres (Andreev et al 2010;Vantsevich 2014).…”

Section: Literature Reviewmentioning

confidence: 99%

“…The lead of the front axle wheels (percentage) was calculated according to the following equation (Janulevičius et al 2017):…”

Section: Calculation Of Measured Parametersmentioning

confidence: 99%

Impact of the Inflation Pressure of the Tires on Lead of Front Drive Wheels and Movement Resistance Force of Tractors

Janulevičius

Gurevičius

2019

Transport

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The transmission of mechanical front-wheel drive tractors normally has a front axle lead ratio, which is equal to 1.5…2.5%. Naturally, when ballast masses are added to the tractor or when inflation pressure in the tires is reduced, distortion of the tires is inevitable, which changes the lead of the front wheels. In this paper, we present the impact of tire inflation pressures on the lead front drive wheels and movement resistance force when the tractor travelled with a front drive axle enabled and was engine braking with the fuel supply off. It was found that the variation in front and rear tires inflation pressure combination can significantly change the lead of the front drive wheels. For the tested tractor up to 6.9%. The result is that when the tractor travelled with the front axle enabled and was engine braking, the engine-braking efficiency decreases with increasing lead of the front wheels. Front (slipping) wheels create the opposite-direction torque, which is transferred to the rear wheels through the tractor’s front-rear axle drive system. Additional losses of the engine braking occur in transmission due to power circulation, and the result is that the tractor wheels receive less braking torque from the engine.

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“…This change has no harmful effects on the tractor vehicle dynamics while working, because when running a good road and at higher speed, the front wheel drive is generally unplugged. However, front-wheel accelerates change effects of the MFWD tractor braking dynamics, since the braking front axle is always automatically enabled [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Tractor MFWD braking deceleration research between different wheel drive

Gurevičius¹,

Janulevičius²

2017

Engineering for Rural Development

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Abstract. The article presents and analyses the reasons of the braking parameter in 4×4 tractor. It is noted that the wheeled tractors are working in transport, cargo, driving with implements and without them in the fields, etc. for most of the time. The contact area with the road surface during braking decreases when increasing the driving speed and the overall dynamic stiffness of the tire changing increases the rolling resistance. However, it is worth mentioning that the tire contact with the road surface area is also dependent on the tire air pressure and improperly selected or uneven tire air pressure to increase the vehicle rolling resistance, increasing the frontwheel lead, which reduces the braking efficiency. The change of the front-wheel lead increases kinematic discrepancy between the drive wheels. These factors have negative effect for the tractor performance parameters, the transmission is loaded heavily, the power losses are increased, tires wear faster, the fuel consumption is increased. This article shows and analyses tractor deceleration between different wheel drive (4×2 and 4×4) with different driving speed.Keywords: inflation pressure, deceleration, braking, agricultural tractor. IntroductionTractors are identified as MFWD (Mechanical Front-Wheel Drive) tractors, when the front axle is driven by a mechanical drive and the front drive wheels are smaller than the rear wheels. Today, MFWD tractors are extensively used for transportation work when connected to the tractor trailer or semi-trailer. The latter considerably increases the tractor rear wheel vertical load and the rear tire deformation, but reduces the front-wheel vertical load and tire deformation. Increasing and decreasing the rear of the front tire deformation increases the actual size of the front wheel advance. This change has no harmful effects on the tractor vehicle dynamics while working, because when running a good road and at higher speed, the front wheel drive is generally unplugged. However, front-wheel accelerates change effects of the MFWD tractor braking dynamics, since the braking front axle is always automatically enabled [1][2][3][4].Brake and steering systems in vehicles are the most effective gear, which directly affects the vehicle dynamics. In general, the brake system is running in the longitudinal vehicle dynamics and driving dynamics system running side. However, their effects combine when the vehicle is braked on uneven surfaces. The yaw moment braking compensates for steering control on the road. To avoid improper steering compensation vehicles have been equipped with the wheels being driven in rotation angle of the controller, designed to mitigate the impact of asymmetric braking forces and stabilize the angular deviation in vehicles [5][6][7].Freight transportation tractors are combined with various trailers or semi-trailers. Almost 75 % of kinetic energy of the tractor-trailer combination is acquired from the trailer, so it is very important that the brake system of the trailer is sufficient to defeat the e...

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Dependencies of the Lead of Front Driving Wheels on Different Tire Deformations for a MFWD Tractor

Cited by 22 publications

References 28 publications

Estimation of tractor wheel slippage with different tire pressures for 4wd and 2wd driving systems

Estimation of tractor wheel slippage with different tire pressures for 4wd and 2wd driving systems

Impact of the Inflation Pressure of the Tires on Lead of Front Drive Wheels and Movement Resistance Force of Tractors

Tractor MFWD braking deceleration research between different wheel drive

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