The power of the engine of energy-saturated tractors often proves not to be fully used. One of the solutions to this problem might be the use of the unit technological part as an active coupling weight. To implement it, an energotechnological modular unit was created.Research purpose The purpose of the study is to determine the traction efficiency of a block-modular energotechnological unit given a kinematic discrepancy between the tractor wheels.Materials and methods The system of equilibrium equations for the transport-technological module being free-attached to the energy module is presented as the sum of forces projections on the axis. The tangent thrust force and the rolling resistance force of each axle of the energy vehicle were expressed through the corresponding normal soil reactions. When calculating multiaxle running systems, it was taken into account that the rolling resistance coefficient depends on the number of wheel passes along one trace and the degree of soil deformation by previous passes. Normal reactions of the soil to the energy module supports have been determined by considering the modular energotechnological unit as a whole, equating to zero the sum of the forces projection on the OZ axis and the sum of the moments at the point of contact between the energy module’s front wheels and the soil.Results and discussion The influence of the kinematic mismatch between the third axle and the second one on the undercarriage efficiency was investigated. Analyzing the dependence of the running system efficiency on the kinematic mismatch of the first and third axles at the traction of 30 kilonewtons, the extremes of all the dependencies at the kinematic mismatch between the third bridge and the second one different unit were detected.Conclusions It has been revealed that the change in the efficiency of the chassis system of the modular energotechnological unit depends on the kinematic mismatch between the third axle and the second one at a predetermined kinematic mismatch between the first axle and the second axle, which is a structural feature for 4K4 wheeled tractors. The excess in the values of running system efficiency equals 1.04-1.06 if the constructive kinematic mismatch between the third bridge and the second one is within 1.06-1.08.
