Optimisation and Benchmarking of Heavy Duty Truck Transmission for Gear Strength, Shift Quality and Fuel EconomY 2003-26-0028
This paper describes the optimisation of a Heavy-duty truck transmission for performance parameters like Fuel Economy, Gear strength, Life, and Shift quality. The design parameters, namely, Gear Pair Geometry, Driveline Ratios and Synchronizer parameters are optimised to upgrade an existing 50 kgf.m (490.5 N.m) input torque capacity transmission to be used with 60 kgf.m (588.6 N.m) input torque capacity and higher GVW. This transmission has been benchmarked with a commercially proven 50 kgf.m (490.5 N.m) capacity transmission.
Effect of adding an overdrive, and proper driveline matching to achieve higher fuel economy were studied for the selection of gearbox ratios.
Macro geometry and tooth profiles of gear pairs are optimised to achieve the highest possible contact and bending safety factors, within the imposed constraints on design. Micro geometry and tolerancing experiments were carried out to reduce the transmission error and hence noise.
Shift quality parameters of manual transmission, namely shift time, shift effort and heat loading of synchronizers are evaluated by simulating the synchronization process within the transmission and varying the design parameters like cone angle, number of cones, cone size etc.