Fundamental realization of longitudinal slip efficiency of tractor wheels in a tillage practice

• Published in: Soil & tillage research 2021-01, Vol.205, p.104765, Article 104765
• Main Authors: Shafaei, S.M., Loghavi, M., Kamgar, S.
• Format: Article
• Language: English
• Subjects: Gross traction force; Implement draft force; Overall power efficiency; Slip efficiency; Wheel slip
• ISSN: 0167-1987; 1879-3444
• DOI: 10.1016/j.still.2020.104765

•Slip efficiency of the MFWD tractor wheels was ascertained.•The slip efficiency was mainly affected by tillage operational depth than speed.•The slip efficiency linearly dropped as implement draft force augmented.•The slip efficiency augmented as decrement of slip and gross traction ratio.•To maximize the slip efficiency, slip control of the wheels is suggested. Longitudinal slip efficiency of driving wheels of off road vehicles is function of not only slip of all driving wheels but also their gross traction force. In this work, the slip efficiency was ascertained for a mechanical front wheel drive (MFWD) tractor in a tillage practice. Front and rear driving wheels of the MFWD tractor performed in unequal traction circumstances (size, inflation pressure, and dynamic vertical load) and soil cone indices. Obtained results indicated that the slip efficiency nonlinearly dropped from 0.94 to 0.74 as simultaneous augmentation of slip ratio of the rear wheels to that of the front wheels (0.72-0.87) along with ratio increment of gross traction force of the rear wheels to that of front wheels (1.81-4.93). These conditions occurred, when draft force requirements of implement augmented from 8.58 to 25.85 kN. Hence, it can be pointed out that the maximum slip efficiency as well as overall power efficiency of the MFWD tractor in tillage practices would be achieved at the same slip in accordance with the same gross traction force of the front and rear wheels. To do this for, specific tire type (radial or bias ply), automatic slip control of the wheels by implementing wheel slip control system would be beneficial, especially in case of lower slip than 0.2 for achievement of maximum tractive efficiency. It must be noted that adjustment of inflation pressure of the tires is also advantageous followed by ballast weight application in this realm.