Fuel economy and performance improvement enabled by medium-duty dual clutch transmissions

Abstract

In the past decade dual clutch transmissions (DCTs) have gained significant market share over torque converter automatic (TCA) transmissions in the passenger car sector, partially due to fuel economy improvement. Although today's North American medium-duty (MD) truck market is predominantly TCA technology, DCT technology has the potential to improve MD truck fuel economy and performance. This paper includes detailed comparisons of the key technology hardware and controls differences, their influence on driveline efficiency, and vehicle application optimisation. The losses of a DCT and a TCA were characterised over their relevant operating ranges and then incorporated into MATLAB®/Simulink® models. The models were validated with chassis dynamometer data and are capable of quantifying the trade-off between vehicle performance requirements and fuel economy. The analysis concludes with results from the fuel economy studies as well as observations of other performance benefits of the DCT technology in the MD market space.