Liebherr has announced the industry’s first hydraulic hybrid drive for mobile harbour cranes. The new Pactronic - hybrid drive system addresses two critical issues: increasing handling performance and reducing fuel consumption.
The Liebherr Pactronic is a new hydraulic hybrid drive system. It is characterized by an energy storage device. A hydraulic accumulator supplements the fluid pump in delivering power to the system. It serves as a pressure storage reservoir incorporating a gas in conjunction with a hydraulic fluid. Energy is stored in this compressed gas to be released upon demand.
The Liebherr Pactronic is also an impressive power booster. Hoisting as well as lowering speeds are increased substantially – without the need to go for a bigger diesel engine with more output. In addition, the crane’s fuel consumption is significantly reduced. This is achieved by fully utilizing the reverse energy and surplus power within the system.
The conventional, hydrostatic hoist system of a Liebherr Mobile Harbour Crane is driven by a hydraulic motor, a pump and the prime mover (diesel or electric engine). With Pactronic a secondary energy source is added to the drive system. Charging of the accumulator is done by regenerating the reverse power while lowering the load. In addition, the surplus power of the primary energy source is also used for charging. The stored energy of the accumulator is transferred back to the system when the crane requires peak power during hoisting. Consequently, the total hoisting power is the sum of the conventional hydrostatic power and the secondary energy, provided by the accumulator.
Pactronic is most useful in situations where peak power is required, such as dedicated bulk handling for example. In-line with the fuel consumption, CO2 emissions are also decreased by 25-35%. It is also beneficial for those users operating their cranes nearby residential areas where noise emissions are a crucial criteria as another key advantage of the Pactronic is its reduced noise exposure. When an application is started that requires the additional power, the Pactronic can transfer power back to the system and increase the hoisting capabilities of the crane.
