When the driver presses the brake pedal, a hydraulic unit integrated in the drive train presses the hydraulic fluid into a high-pressure reservoir. The resulting resistance makes the vehicle decelerate. When accelerating, the hydraulic pressure reservoir is controlled electronically to release the pressure and it relieves the load on the diesel engine. As a result, the engine consumes less fuel, generates less exhaust gases, and functions more quietly. 

The compact Rexroth HRB is ideal for use in various commercial vehicles. The HRB can be integrated and even retrofitted in the chassis as an add-on system, without major modifications.

The system reduces fuel consumption by up to 25% in vehicles used for very short distances such as urban buses, garbage trucks, fork lift trucks or delivery vehicles driven in city traffic. Fuel consumption can also be reduced considerably in other commercial vehicles and trucks used for intercity service.

Each time a driver brakes, the HRB system stores energy which would otherwise be lost. The hydrostatic hybrid drive functions almost maintenance-free and wear-free compared with electric hybrid drives. For example, it is not necessary to regularly change the battery. In addition, the HRB also improves the acceleration of the vehicle. The additional drive energy allows vehicles to be equipped with smaller diesel engines and therefore further reduce fuel consumption and emissions.

All Rexroth HRB components are based on standard components from the manufacturer's current product portfolio. Prototypes of the Rexroth hydrostatic hybrid drive are currently being tested in on-road vehicles.

This article was contributed by Bosch Rexroth Canada, the Canadian partner company of Bosch Rexroth AG, a global specialist in the field of drive and control technologies.
www.boschrexroth.ca