The effect of the liquid ballast and tire inflation pressure on tractor performance parameters

Abstract

A three years research project was developed to study tractor-implement dynamics in tillage operations. The field tests with trailed disc harrows were performed under real working conditions, in dry medium textured soils, in primary and secondary tillage. The specific objective of the study was evaluating the liquid ballast and tire inflation pressure effects on tractor performance parameters. Were tested two different static ballasts, with and without tire liquid ballast, and three different inflation pressures: the inflation pressure specified by the manufacturer of tires (100 kPa in front tires and 70 kPa in rear tires); the inflation pressure specified by the tractor manufacturer (140 kPa in the tires of both axles); and the inflation pressure typical of the farmers in region (190 kPa in the tires of both axles). A four-wheel-drive, 59kW (DIN), Massey-Ferguson 3060 Datatronic tractor and two trailed type medium-weight offset disc harrows, was used in the field trials. The instrumentation system to determine energy requirements and efficiencies of tractor-implement, include a portable computer based record system mounted in the tractor, developed to record the information provided by TPM "Datatronic", which also records the information from a load cell based pull measuring system. The evaluation parameters were: the slip, the real distance, the work rate, the overall energy efficiency and the fuel consumption per hectare. The field tests were conducted in different soil and conditions types. The results obtained show that the use of the liquid ballast in the tires didn’t improve the work rate, and it even caused a 5 to 10% increase in the fuel consumption per hectare. To avoid soil compaction, as well as to permit a more efficient general utilisation of the tractor, the common and indiscriminate use of liquid ballast should be questioned. It was also proved that concerning the situations of tire inflation pressure specified by the tractor manufacturer and the inflation pressure specified by the manufacturer of tires, there were no significant differences, both in work rate and in fuel consumption per hectare. The use of higher tire inflation pressures, showed a light diminution (3% to 5%) in the work rate and a great increasing in the fuel consumption per hectare (10% to 25%), even in good traction conditions displayed by the interval of slip values (7% to 15%). In these dry farming soils the above practices should be questioned.