Advanced Powertrain With Energy Storage (APWES)

A consortium led by Caterpillar will build a continuously variable transmission that stores braking energy in a spinning flywheel, designed for bulldozers, excavators, and other off-highway vehicles. Off-highway machines—used in construction, mining, and agriculture—consume large amounts of diesel fuel and produce significant CO₂ emissions. Current transmissions waste much of that energy as heat during braking or deceleration. This project addresses that inefficiency by combining a hydrostatic transmission (which uses fluid pressure to vary speed smoothly) with a flywheel energy storage system. When the machine slows down, the flywheel spins up and captures the kinetic energy; when the machine accelerates again, that stored energy is released back into the drivetrain. If the system works as intended, it could cut fuel consumption and CO₂ emissions substantially, and allow manufacturers to fit smaller engines without losing performance. The £4.16M grant from the Advanced Propulsion Center funds a 48-month development programme led from Caterpillar’s Wolverhampton facility, with partners in Peterborough, Desford, Silverstone, and Hatfield. The technology is not intended for passenger cars—it targets the heavy machinery that underpins construction and infrastructure projects, where even modest efficiency gains multiply across thousands of working hours.