Hydraulic Hybrid

Our patented Hydraulic Launch Assist™ or HLA® hydraulic hybrid system has two main parts: regeneration and acceleration. During regeneration the vehicle’s kinetic energy that is normally lost during braking is captured and used to drive the pump/motor as a pump. The pump action transfers hydraulic fluid from a low-pressure reservoir to a high-pressure accumulator. As the fluid pumps into the accumulator it compresses nitrogen gas and pressurizes the system. The regenerative braking captures about 70% of the kinetic energy produced during braking.

For acceleration, the fluid in the high-pressure accumulator is released to drive the pump/motor as a motor. The motor then propels the vehicle by transmitting torque to the driveshaft.

The Eaton HLA® system has two different operating modes: Economy and Performance. When operating in Economy Mode, the energy stored in the accumulator during braking is used alone to initially accelerate the vehicle. Once the accumulator has emptied, the engine will begin to perform the acceleration. This process results in increased fuel economy. In Performance Mode, acceleration is created by both the energy the stored in the accumulator and the engine. Once the accumulator has emptied, the engine is completely responsible for acceleration. While fuel economy improvements are seen in Performance Mode, the greatest benefit is increased productivity.