New levels of sophistication

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Technological innovations mean that couterbalance trucks are reaching new levels of sophistication.  Jessica Davies looks at the latest developments.

Rising fuel costs, more stringent exhaust gas standards and global competition mean that drive technologies must be redeveloped for the future. Manufacturers are working hard to develop core technologies to deal with these issues, and the latest in counterbalance truck designs demonstrates this.

Green issues are dominating truck designs. The technologies being developed range from hybrids, to the creation of completely new drive technologies. Some manufacturers are primarily focusing on alternative fuels for engine trucks. Research has shown that various forms of bio-diesel can be used in the same engines designed for fossil fuels, which rules out the need for businesses to invest in new trucks.

Russell Baker, Hyster’s UK territory manager, says: “There is increasing focus on energy-efficient features from the obvious low fuel consumption engines to the more detailed development of CANbus wiring, low energy LED lights, efficient transmissions (which help reduce excessive fuel consumption caused by driving style), tyres with lower rolling resistance and engine management systems.”

Baker reckons the price of fuel has quickened the shift of customers to electric-powered trucks. “Also, more and more customers are asking for emissions and fuel consumption data because of the increased emission legislation,” he says.

Doug Wyatt, national technical manager at Nissan, says: “The rise in fuel costs will undoubtedly affect the type of fuel used in trucks.” Some say it will quicken the take-up of hydrogen fuel cell technology.

It is the cost of technologies, such as hydrogen fuel cell, which is stopping these innovations from mass production. But David Bowen, sales and product manager at Linde, says: “If fossil fuel prices continue to increase, new technologies may cease to be so expensive compared to what we’re using now.”

Linde revealed a hydrogen-powered drive truck with direct injection and compressor at the CeMAT exhibition in Hanover in May. The concept truck, based on its 39x series, has a load capacity of three tonnes. Its thrust-controlled fuel tank system and the intercooler attached to the overhead guard, make it stand out from conventional engines. The fuel tank system is mounted on the counterweight and is in between the truck’s b-pillar.

To replace the pressure pump the fuel tank is reversed onto a rail system where the cartridge is removed from the side. This cartridge consists of a thin-walled inner aluminium container that is encased with carbon fibres and epoxy resin. It can hold around 26 litres of hydrogen, which is pumped into the pressure pump at 350 bar, which is equal to 2.3 litres of diesel.

The engine, made by Volkswagen, has a 2.0 litre piston capacity and a 43kW power rating at 2600rpm. The hydrogen stored in the pressure pump is blown directly into the engine’s combustion chamber, enabling the fuel to burn efficiently.

It does not give off any harmful emissions, because the fuel is turned into water vapour, and can still reach its full power rating when operated with hydrogen. But Bowen says there are still technological advances needed before hydrogen-powered trucks can be made commercially viable. For example, each truck must have a bigger fuel storage capacity on board. Also, there isn’t the infrastructure to support it.

Nissan’s DX-Eco engine range features single-point fuel injection. Doug Wyatt, national technical manager for the company, says this type of engine has done well in the automotive market. Together with Nissan’s Tri-cat Ultra fuel management system, the range provides 99 per cent lower emissions.

Hybrid technology is coming more to the fore, with many forklift manufacturers now developing it. At CeMAT Linde had a forklift truck with an electric motor as well as an internal combustion engine that can operate as a starter and generator. By combining the two technologies, energy consumption can be reduced by up to 25 per cent.

The internal combustion engine still forms the basis of the drive train. But extra energy capacity is gained from the synchronous motor, a 400 volt lithium-ion battery and an energy management system in the truck.

To save fuel, the internal combustion engine automatically switches itself off when the truck stops. When continuing to drive it automatically switches back on. This can help cut down on the amount of energy wasted when a truck is idle but still running, which can be up to 30 per cent of their operation time. The energy recovery system works by turning braking energy into electric energy and storing it in the battery.

Toyota has also revealed its own hybrid concept forklift for the first time to the European market. The technology is based on that used in its popular Prius range, and uses a combination of electric and internal combustion technology. The forklift shifts automatically between battery and engine mode, simultaneously recharging the battery during operation.

Still’s standard RX70 has been redeveloped into a pure hybrid truck, complete with electric energy storage. Energy recuperated when braking is channelled to accelerate the truck, which helps reduce consumption up to 11 per cent for work cycles with a high share of acceleration and braking, for example, when loading and unloading lorries.

As for electric powered trucks, emphasis is on minimising energy consumption to increase shift life. Linde’s electric counterbalance range drive-axle has electronic power modules mounted on the axle rather than, more typically, at the other end of the truck. “This means we can use short power connections conserving up to eight per cent of total battery energy,” says Bowen.

It may not be the conventional lead-acid battery that dominates electric-powered trucks in the future. The lithium-ion (li-ion) battery is proving a strong contender. There are several operational advantages of using a li-ion battery over a lead-acid.

For example, it provides more power, and it can charge more quickly. It can also boast a longer life than a conventional battery. Nissan’s Doug Wyatt says they can last twice as long as conventional lead-acid batteries.

After a while the latter becomes more difficult to charge. This is because the polar plates become sulphated, which causes resistance. Whereas the reaction process between electrons and lithium-ion is reversible. This results in a longer life for the battery, and reduces replacement costs.

Li-ion batteries are virtually maintenance-free, because the cells don’t need to be refilled with water as they do with lead-acid batteries. Wyatt says it is similar to the technology used in computer and mobile phone batteries, so the size of them can be reduced, while retaining the same capacity as a lead-acid. Trucks with lead-acid batteries need to be designed so that operators can easily access the top of the battery. Li-ion batteries could strip away this limitation. Wyatt says: “This would give way to fresh counterbalance designs.”

Less energy is needed to fully charge a li-ion battery, and there is less energy loss during charging and discharging. It can also recover more energy from regenerative braking, which means they can operate over longer work periods. Wyatt says the li-ion batteries are even easier to dispose of than the conventional type, because they don’t contain such harmful pollutants such as lead, mercury or sulphuric acid.

You would think with this string of advantages the take-up of this technology would be a no-brainer. But of course, like most things, there’s a down side. It’s pricey. Wyatt says: “The next step in the development of the li-ion battery, will be to bring the price of it down.”

Hyundai has expanded its range of AC forklift trucks up to 3.2 tonnes and says these B-7 series forklifts boast several improvements. Using AC motors instead of DC gives more than ten per cent improvement in motor efficiency and changing motor brushes is no
longer required. A dual drive system gives improved performance notably a superior turning radius. The company says an additional benefit is a reduction in maintenance costs.

Nissan used CeMAT to show its first li-ion forklift concept model. It uses lithium-ion battery technology developed by Automotive Energy Supply Corporation, a joint-venture between Nissan, NEC and NEC Tokin.

Toyota has also previewed its latest 48-volt electric counterbalance truck saying that this model is the most compact yet. It is available in three and four wheel models and has load capacities ranging from 1.5 to 2.0 tonnes.

Historically, counterbalance trucks have lagged behind some of the more sophisticated innovations seen in warehouse trucks, but this is no longer the case. Manufacturers are now churning out trucks which can boast good productivity levels, better fuel efficiency, and reduced energy consumption. Today’s exorbitant fuel prices may end up quickening the rate at which these designs are brought to market for mass production.

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