The SMV 4531 features:
- A hybrid diesel/electric driveline which Konecranes describes as a serial configured diesel/electric system consisting of a diesel engine, an electrical generator and an electrical traction motor. The diesel engine runs at constant RPM for optimum fuel efficiency and powers the generator. Propulsion is provided by an electric motor that is an integral part of the drive axle. This motor also generates electrical energy when braking, minimizing the need for mechanical braking and saving energy.
- An electrified hydraulic lifting system which, unlike in a conventional reachstacker with the diesel engine mechanically driving variable displacement piston pumps that provide the hydraulic energy for lifting and steering, the hydraulic pumps in the new hybrid reachstacker are electrically driven and electronically controlled. Dedicated electric motors drive the pumps that provide the hydraulic energy for lifting and steering. The speed of these pumps can be controlled independently of diesel engine speed. More importantly, the return flow from the hydraulic cylinders is not converted into heat, but fed backwards through the pumps which now act as hydraulic motors, thus regenerating electrical energy.
- A super capacitor based energy storage system that is connected to the truck’s electrics. Unlike a traditional reachstacker’s conventional batteries that are used for starting the engine and powering the electrical systems including lights, this system stores electrical energy that has been recovered for later re-use, and boosts the diesel powered electrical generator at times of peak power demand.
- Significantly reduced diesel fuel consumption and emissions. Estimated fuel consumption at normal handling of fully loaded containers will be at least 30% lower than for equivalent diesel powered reach stackers. 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 that all can operate in regenerative modes. The energy generated from braking and load lowering is recovered and stored for later re-use. This results in a substantial reduction in diesel fuel consumption and environmental impact. Meanwhile, productivity is increased in terms of quicker response and higher acceleration,” says Anders Nilsson, Konecranes Lift Trucks’ technical director.
“Potentially, the diesel engine of the hybrid reachstacker could be replaced by another source of electrical energy, as technology and price allow. Such examples may be fuel cells or an energy storage that can be recharged via a connection to the power grid,” added Nilsson.