Finland-based crane and heavy-lifting equipment manufacturer and services provider Konecranes has launched the world’s first hybrid reach stacker, powered by a hybrid diesel-electric driveline, an electrified hydraulic lifting system and a supercapacitor-based energy storage unit.

Used for container handling, the new SMV 4531 TB5 HLT hybrid reach stacker, which features a 45 t lifting capacity, aims to cut fuel consumption and emissions by at least 30%, improve performance and acceleration, as well as command response time.

“This is an exciting step forward for our industry, further proving that our company is committed to offering customers eco-efficient products and services,” says Konecranes VP and Lift Trucks business unit head Lars Fredin.

He adds that the new hybrid reach stacker will provide customers with substantial cost savings and environmental benefits by significantly reducing diesel fuel consumption. This is achieved by electrifying all flows of energy across the driveline, the hydraulic lifting system and the energy storage system.
“Propulsion and lifting are powered by dedicated electric motors, which operate in regenerative modes. As a result, the energy generated from braking and load lowering is recovered and stored for reuse, which results in a substantial reduction in diesel fuel consumption and its the environmental impact,” explains Konecranes Lift Trucks technical director Anders Nilsson.

He adds that productivity is increased, owing to a quicker response and improved acceleration. Further, the diesel engine could be replaced by another source of electrical energy, depending on the price and the availability of technology, such as fuel cells or an energy storage unit that can be recharged through a connection to the power grid.

While conventional mechanical reach stacker driveline systems comprise a diesel engine, a torque converter and transmission, the driveline in Konecranes’ hybrid reach stacker is a serial configured diesel-electric system, comprising a diesel engine, an electrical generator and an electrical traction motor.

The diesel engine runs at constant repetitions per minute for enhanced fuel efficiency and powers the generator, while the electric motor, an integral part of the drive axle, propels the vehicle. This motor also generates electrical energy when braking, thereby reducing the need for mechanical braking, which saves energy.

Meanwhile, hydraulic pumps in Konecranes’ hybrid reach stacker are electrically driven and electronically controlled, as dedicated electric motors drive the pumps that provide the hydraulic energy needed for lifting and steering. The speed of these pumps can be controlled independently of diesel-engine speed.

Moreover, the return flow from the hydraulic cylinders is not converted into heat, but fed backwards through the pumps, which now act as hydraulic motors, thereby regenerating electrical energy.

In a conventional reach stacker, the energy generated while lowering goods dissipates and is wasted, as the diesel engine mechanically drives variable displacement piston pumps that provide the hydraulic energy for lifting and steering.