Tractor performance testing on axle dynamometers: Choice of torque setting and interpretation of results

Abstract

There is interest both in Europe and in the U.S.A. in the power testing of tractors on axle dynamometers as an alternative to the conventional test track method. Proposals have been made to both the OECD and ISO, who set the test standards. This report outlines computer programmes which have been written to: (1) enable the operator of a dynamometer to select axle torques appropriate to the tractor under test. (2) Model the tractor under draught load on either a test track or agricultural surface calculating slip, pull and drawbar power. This is to make the results of the test comparable with those obtained on test tracks and make them more meaningful to farmers. An example is given in which the computer programmes were employed in the testing of a 100-kW tractor in two- and four-wheel drive modes.