Abstract
This paper explores the potential of variable displacement motors to reduce energy consumption in a compact track loader’s drivetrain. While conventional track motors are fixed displacements, variable displacement motors offer operational flexibility that enables downsizing of the drivetrain pumps and hybridization. The Variable Displacement Linkage Motor (VDLM) is specifically designed for low-speed, high-torque applications without the need for a gearbox. The linkage mechanisms and rolling element bearings offer high mechanical efficiency even at reduced displacements. A multi-cylinder prototype of the VDLM has been experimentally tested and its performance map incorporated into numerical models of various drivetrain configurations to evaluate its potential to save energy. Two modified drivetrains are considered: conventional hydrostatic transmission (HST) with pump downsizing and series hybrid configuration. By considering the optimal control of the hydrostatic drivetrain with downsized pumps and the series hybrid drivetrain through static optimization and dynamic programming, it is found that VDLM can reduce fuel consumption by 5.1% with downsizing of the HST pumps, and by 43.0% in a series-hybrid configuration.
