Fuel consumption analysis of an agricultural tractor working on wet soil with different combinations of ballasts on the wheels and tire inflation pressures.

Abstract. The agricultural tractor is present in all stages of agricultural production, from the initial preparation of the soil to the transportation of the final product. Many are the ways for controlling the quality and efficiency of its work, among which we highlight tire pressure and ballasting. However, a determining factor that cannot be controlled is climate. So, the only option is adjusting the tractor to soil moisture in order to allow better efficiency where the use of the correct pressure and ballast have to provide satisfactory fuel consumption. Thus, this work aimed at evaluating the hourly and specific fuel consumption of an agricultural tractor using different three ballasts and five tire pressures working in soil presenting a field capacity of 150 m3 /m3 of moisture. The experiment was conducted at the Palmital farm of the Federal University of Lavras (UFLA) in Ijaci City, Minas Gerais, Brazil. The soil was adapted to the field capacity by means of a central pivot and assessed in the field by an electric field sensor. The tractor used was an A950 Valtra 4x2 TDA, , 95 horsepower (69.8kW) at 2200 rpm according to the ISO TR 14396 Standard, assembled on 18.4 – 34 R-1 diagonal back tires and 14.9 – 24 R-1 front tires. The breaking tractor used was a BX 6110 4x2 TDA Agrale, 105 horsepower (77.2 kW) at 2300 rpm, assembled on 18.4 – 34 R-1 diagonal back tires and 14.9 – R-1 front tires. A HBM U1 charge cell of 5 tons connected both tractors in order to assess the force of the draw bar. The fuel consumption was measured by means of an Oval flow meter and the slippage was measured using the marks and times method. The experimental design was completely randomized, assembled in a 5x3 factorial scheme, with 15 treatments and 3 replicates. The results of the volume and specific fuel consumption parameters showed the highest efficiency using the 47.5 kN and the 44.67 kN ballasts, 110 kPa of back tire pressure and 97 kPa of front tire pressure.