Determining the environmental impact of the fuel consumption of agricultural tractors: simulation and comparison

Abstract

Fuel saving in agricultural machinery is needed for both, limiting the increasingly costly energy demand in agricultural farms and reducing the greenhouse gases emissions of the agriculture sector. Bench tests are conducted on the manufactured machinery to guarantee the delivered power of the engine and control their pollutant emissions comply with current European regulations. At the same time, field experiments are a useful way to document the real use of tractors and actual emissions during agricultural operations. However, the cost of such campaigns is such that the number of machines tested is low, which limits the comparison between different types of equipment. In this paper, a simulation tool is proposed to combine field measurements and bench results in a same database. To do this, force and energy balances are computed for a mechanical system ranging from operator demand to engine characteristics. Numerical results are used to assess pollution and consumption for different field operations. The general driving scenario used in this approach allows a full comparison of the results for different kinds of tractors. The computed greenhouse gas emissions may be used as an environmental indicator of the vehicle performances. However, this index cannot be directly applied to compare the studied tractors that are in fact used for different agricultural practices. Further work is therefore needed to elaborate some scaling factors to compare tractors across the full range of power and use.