Influence of adjustable front ballast on tractor fuel consumption at winter wheat stubble harrowing

Abstract

Ordinarily a tractor works under variable draft, what brings unavoidably mass transfer of the tractor, which negatively affects the front and rear wheel cohesion with soil and pull. This situation causes discrepancy when loaded MFWD (mechanical front wheel drive) tractor under draft in four-wheel drive regime mode, and this leads to the increase of the front wheel slip. The gross traction ratio developed by the dynamic weight on the powered wheel is different than it should be. The cohesion of the front wheels is changed from maximum, when the draft is minimal, to minimum, when the draft is the highest. The cohesion of the rear wheels is changed contrarily. Mass transfer changes the load of the tractor axles, with the implement draft towards mass position to the rear wheel, the slip of the front wheels becomes unstable. For solving such impact of mass transfer a special attachment of the front ballast with a possibility to change its forward distance was made. The aim of the research was to establish how much the adjustable front ballast can adjust the slip of the tractor, maintain a constant reaction on axles and reduce the fuel consumption. The investigative tractor “Ford 8340” and a compact disc harrow were used in this research. Mathematical method was applied for the search potential of ballast that can generate an appropriate weight transfer of the front and rear axis load. A field test for evaluating of the front ballast adjustable position to wheel slip and fuel consumption was performed. The correlation of the adjustable front ballast, the tractor axle load balance and wheel slip during the disc harrowing operation was developed. The results show that the adjustable front ballast can compensate the draft load on the front and rear axis and improve the wheel-pull distribution by 11% and to reduce the fuel consumption by 5% in the field conditions compared to the case when the front ballast was used by default.