The same market drivers to reduce fuel consumption, to reduce emissions and improve vehicle control as well as productivity that have been the focus of Haldex gear product development have influenced the development of a revolutionary technology called EMS. Contrary to other approaches where electronic control strategies were developed to control existing hydraulic equipment, Concentric started from the opposite direction, devising an optimum control strategy and then successfully building the hydraulic equipment to execute it.
Concentric Energy Management System is intended primarily for off-road applications, such as wheel loaders, excavators, forklifts and for on-road vehicles with a stop-start duty cycle, such as buses, refuse, military, mining, and delivery vehicles.
EMS is a total vehicle hydraulic energy management system. A hydraulic system has two main advantages over electric hybrid systems in the context of heavy vehicles: it can store energy fast and efficiently, unlike batteries and it can distribute energy in a totally controlled manner, unlike capacitors. The EMS system is distinct from all other hydraulic hybrid systems in that the energy can be transferred instantly and simultaneously to all the functions within the vehicle.
The system works by converting vehicle or implement kinetic energy to fluid energy during the braking and implement lowering cycles and simultaneously using it for other functions or storing it within a central accumulator. The vehicle's hydraulic circuits are mechanically coupled via pump/motor units but operate completely independently. Energy transfers are not serial or subject to a hierarchical protocol, which means that energy recovered from one function does not need to be stored before it can be used in another.
Closed loop electronics allow more precise control of energy conversion, minimizing waste. EMS also allows the engine to be completely decoupled from the wheel drives and the hydraulic circuits operating implements. This means that the engine can be designed and sized to run at peak efficiency throughout its duty cycle. Steady state running extends engine life and makes it easier to meet escalating environmental and regulatory demands not only because of increased efficiency and lower emissions but also because of the reduced noise and vibration profile of the whole machine. Fuel usage is dependent upon vehicle duty cycle but fuel savings of up to 50% can be obtained.
In addition to significant reductions in fuel consumption Concentric EMS, provides additional benefits for OEMs engine and vehicle designers. The extremely fast and stable response of EMS will enable more productive, more comfortable and safer machines to be developed. EMS also eliminates a number of power train components, including transmissions, differential, drive shafts, torque converter, power take-off systems and PTO pumps.
EMS development has progressed through high-power system testing within a laboratory environment. This includes implement energy recovery, brake energy recovery, engine management/augmentation, implement control (linear and rotational), ratiomentric steering, and associated electronic controls on systems capable of developing up to 500 HP.