Efficient Drive Systems

A hybrid truck has two energy storage systems. Besides a fuel tank, the truck is fitted with energy stores situated at the rear. These are charged from the energy that is released during braking.

Using the generator powered by the engine, the recovered energy then drives the electric motor. This reduces the strain on the internal combustion engine by around 30 percent during acceleration and lowers the engine speed by approximately 6 percent. Hybrid trucks are therefore particularly suited to work involving frequent braking and acceleration, such as loading and unloading delivery trucks in the beverages industry.

STILL's RX70 series, which already boasted the lowest energy consumption in its class, is now even more efficient thanks to the addition of the RX70 Hybrid (rated capacity of 3.0 and 3.5 tonnes). The RX70 Hybrid is the first series-production hybrid forklift truck. This technology was first presented at German CeMAT 2008 as ready for full production. Its efficiency makes the truck attractive from both an environmental and a commercial perspective. The higher investment will pay off within two years assuming that the truck is operated for 1,500 hours per year.

Besides a fuel tank, the hybrid truck is fitted with an energy store situated at the rear.

Efficiency, quality, and environmental friendliness were the distinguishing features of the first hydrostatic transmissions launched by Linde Material Handling in 1958. Linde Material Handling thereby set a new standard for forklift truck technology. Since then, Linde has continually enhanced its hydrostatic systems, which are characterized by smooth driving, precise positioning, and minimum wear. Enhancements to Linde's hydrostatic systems, combined with electronic developments, are successively reducing fuel consumption and emissions.

The advantages of hydrostatic systems from Linde Hydraulics, such as optimum utilization of performance, precise machine steering, and dynamic handling, are also used by companies in other industries. For example, manufacturers of construction, agricultural, and forestry equipment as well as municipal vehicles rely on components from Linde Hydraulics.

Linde trucks fitted with a hydrostatic drive can be identified from their two pedals, one for driving forward and one for reversing. Braking is not necessary as the vehicle stops when the pedal is released.

Linde hydrostatic systems are also used in harvesters weighing up to 40 tonnes. The advantages: safe braking and total reliability in continuous operation.

Linde technology can also be found in heavy-duty construction equipment.

Fuel-cell powered trucks are equipped not with a battery but with a fuel cell. They also have a tank for storing hydrogen gas. The electricity obtained from the hydrogen is supplied to electric motors that power the trucks. Fuel-cell powered trucks also have supercapacitors ('supercaps'). These provide the extra power required when driving off or lifting.

Fuel-cell powered trucks are refueled at hydrogen fueling pumps in a similar way to how cars are usually refueled. The waste product resulting from splitting the hydrogen molecules is pure water. These trucks do not have batteries that need to be replaced and charged, nor are there any of the safety risks associated with battery acid. Drivers simply need a valid driver's license and instructions on operating the truck.

STILL tow tractors with a fuel-cell drive system are already used at Hamburg Airport. In the long term, the airport plans to replace its fleet of baggage transporters so that it can reduce harmful exhaust emissions. It also intends to acquire additional vehicles fitted with fuel cells.

KION is involved in a research project to improve handling and environmental friendliness using a fleet of industrial trucks with a fuel-cell hybrid solution. Fronius, an expert in battery charging systems, is developing and building a fuel cell while Linde is converting a fleet of ten industrial trucks for the solution. DB Schenker will deploy the trucks in a year-long field test starting at the end of 2012. A lifecycle analysis is being conducted in which all the material and energy flows are being examined over the lifetime of a product or service. The results will be compared with other systems and enable the impact on the environment to be calculated.

Linde T20 SP pallet truck with a fuel cell from Fronius International.

While electric drives are still in their infancy in the automotive industry, this safe, mature, and economical technology has been powering forklift and warehouse trucks for decades. The useful life of a typical Linde or STILL forklift truck can be as much as 40,000 operating hours, during which time a passenger car would clock up around 2.5 million kilometers. The small lithium-ion batteries in electric forklift trucks, whose individual cells can be installed completely flexibly, result in extra space that is used to make improvements to the truck's ergonomics.

Decades of experience with electric drives have given the KION Group a wealth of expertise that it is using to expand its Electronic Systems & Drives (ES&D) unit. This knowledge is being applied to produce not only excellent electric forklift trucks but also rail, road, and airport vehicles. The findings from these projects are incorporated into the manufacture of electric forklift trucks.

ES&D worked with the KION company Proplan, which manufactures explosion-protected trucks for Linde Material Handling, to develop an electric trolley for Zwiehoff GmbH. The ROTRAC E2 tows rail vehicles weighing up to 200 tonnes at up to 6 kilometers per hour. This task would normally be carried out by a heavy diesel switcher, but the advantage of the ROTRAC E2 is that it can be moved from track to track in no time. The 3.5-tonne ROTRAC E2 sits on four wheels fitted with rubber tires. They are driven by four motors, two on each of the two axles taken from series-production electric trucks. The steel track rollers for moving along the rails can be raised to enable the trolley to be switched between tracks.

Hamburg-based Karabag has launched the New 500 E electric car. The drive unit, control unit, and regulating unit are all taken from KION trucks manufactured in large-scale series production. KION is adopting a multi-brand approach in this project: Linde Material Handling is supplying components for production and service while STILL's contribution is its unique Europe-wide network of service centers. The New 500 E uses approximately 11 kWh over a distance of 100 kilometers. Its emissions of 4.4 g/km are substantially less than those of the gasoline version (119 g/km).

Laweco, a manufacturer of customized lifting solutions, is currently testing a new CargoMaster for the A380 in a pilot project at Munich Airport. While Laweco is responsible for building the chassis and for the overall vehicle, Linde Material Handling is supplying the engine and converter as well as the hardware and software for controlling the vehicle – all designed to interact seamlessly with one another. An innovative feature is the high level of recuperation, allowing the energy released when lowering the lift to be fed back into the battery. The vehicle's lift unit can be controlled extremely precisely – something that is absolutely essential in this environment. After all, a minor mishap resulting in damage to the airplane's fuselage would have serious consequences. That is why the project partners have turned to KION's experienced ES&D team.