Abstract:

The transmission is an important part of the power train system. Its efficiency level directly affects the vehicle fuel economy. The influence of the torque, speed and ratio and the statistical rule of fitting coefficient were revealed by using the method of data fitting based on the test data obtained from a lot of tests carried out to appraise the efficiency of heavy vehicle mechanical transmission accurately and rationally. The relation between fitting coefficients and theoretical model was discussed, and the significance and deficiency of maximum torque point efficiency were expounded. A new definition of the comprehensive efficiency was reated by using weighting coefficient. Through correlation analysis, an evaluation method of common operating point was proposed, the common operating point of heavy tractor was obtained, and the advantage of direct transmission was explained.

Key words: heavy vehicles, transmission, transmission efficiency, evaluation method, weighting, correlation