Work zones of an agricultural tractor with attachment in 4x2 and 4x4 traction schemes
The objective of this study was to identify the work zones of an agricultural tractor with attachment (the case of a Massey Ferguson 592T tractor, with an axial draw disk harrow) for the traction schemes 4x2 and 4x4, gear positions 1st, 2nd, and 3rd and working depths of 5, 10 and 15 cm in agricultural soil. Front traction engagement/disengagement borderlines that divide the work zones were determined through analysis of the different work indexes at each gear position and each depth. The tractor was equipped with a reference wheel, three wheel rotation sensors, a loadcell in the drawbar, a fuel flow meter and a data gathering system developed in LabView. With the measured parameters, slippage, tractor speed, traction power, productivity and specific fuel consumption were calculated in function of the applied load. Index limits were defined to determine when it is more effective to work with the 4x4 or 4x2 scheme. Timely engagement and disengagement of the front traction increases productivity up to 31 % and fuel savings of up to 16 % in different work regimes.