Future fuel drive
June 1st 2008

The future of truck power is changing from traditional fuels to hydrogen and other alternatives, says Mark Sullivan of Linde Material Handling, and the new concepts are gearing up to go

Dwindling oil reserves, more stringent exhaust gas standards and global competition mean that drive technologies must be redeveloped for the future. Today, there are numerous new technologies under development ranging from hybrid solutions to maximize energy efficiency with the fuel currently available, to the development of completely new drive technologies.

"The future is hydrogen – either as a fuel to be fed into an internal combustion engine or used to power a fuel cell to generate electricity for an electric truck," says Mark Sullivan of Linde Material Handling.

At CeMAT, Linde will be showcasing two different hydrogen powered drive concepts for the future, including a 39X series IC truck, the world's first forklift employing a hydrogen engine with direct injection and compressor. The concept vehicle is ready for use and with a load capacity of 3t, it is designed to be highly efficient and to reach its full power rating even when operated with hydrogen.

The principle benefit of hydrogen is that it is currently considered to be the cleanest source of energy, as it predominantly emits water vapour when converted into electric energy. A further benefit is the sheer unlimited availability of hydrogen.

Furthermore, if the hydrogen is produced using electrolysis with renewable energy sources such as hydroelectric power, wind energy or photovoltaic, then the vision of an emissionless energy cycle could become a reality.

In addition to hydrogen engines, Linde has also developed a P250 tow tractor with a hydrogen fuel cell, that will be on display at CeMAT. This vehicle is on the brink of prototype maturity for small series development and over the next seven years, Linde MH plans to send a total of 50 successive industrial trucks with hydrogen technology for a broad range of field tests.

The aim of the field testing being carried out until 2015 is to involve customers from an early stage; this will enable the company to collate important experiences right from the prototype phase, incorporate the results into the next development process and pave the way for series production.

Fuel cells Hydrogen-operated fuel cells offer just as much potential for the future as hydrogen drives, because they are powered by an inexhaustible reservoir of 'green' energy sources, such as sun, water, wind or biomass as well as industrially generated hydrogen.

Fuel cells consist of two electrodes supplied with hydrogen and oxygen. The electrodes are separated by a layer called the polymer-electrolyte membrane, but if they are connected with an electrical conductor, electrical current is generated.

The current generated by the hydrogen supplies an electric motor that drives the tractor. Since emissions are reduced to zero with this technology, hydrogen fuelcell vehicles are also suitable for use in the sensitive food industry. In addition, there is no need to charge batteries for several hours; instead, it only takes five minutes to fill the tanks with hydrogen gas, which can then be stored for a long period of time.

However the primary barrier to hydrogen fuel today is cost.

There is a lack of an economically priced supply of hydrogen gas or fuel cells – fuels cells are approximately four times more expensive than traditional lead acid batteries.

Exactly when manufacturers will launch the first hydrogen product on the market is difficult to determine. Linde Material Handling believes that hydrogen-powered trucks could be economically viable from 2015.

Until then, the company says it will continue to conduct thorough research, develop further enhancements and complete the first truck field tests.

In the meantime, Sullivan notes that ecofriendly technology initiatives are now primarily focusing on so-called "alternative" or "green" fuels for engine trucks. Recent examples have included research into areas such as bio-diesel, bio-ethanol, biomethane, and sun diesel. Since these fuels can be used in engines that were designed for fossil fuels, they obviously remove the need for businesses to invest in new trucks.

Of course, debate has now begun into whether the so-called bio-fuels really are environmentally friendly after all. The negative impact of transforming rainforest into bio-crops may be more damaging than burning fossil fuels.

Hybrid vehicles Another exciting area being favoured as an immediate alternative to traditional electric and internal combustion drives is hybrid vehicles. At the CeMat 2008 intralogistics fair in Hannover, visitors will be able to see a Linde forklift truck with an electric motor in addition to an internal combustion engine that can operate as a starter and generator.

By combining combustion and electrical technologies, consumption can be reduced by up to 25% depending on how it is being used. A further advantage is that emissions are significantly reduced and performance potential is increased.

In the selected mild hybrid solution from Linde Material Handling, the internal combustion engine continues to form the basis of the drive train.

Additional energy capacity is gained from the synchronous motor, a 400V 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 has come to a standstill; when continuing to drive, the engine automatically switches back on. As the trucks can be idling for up to 30% of their operation time, the energy savings are very noticeable. The energy recovery system works by turning braking energy into electric energy and storing it in the battery.

While there are many different technologies under development, when and which technical solution will be the most efficient cannot yet be determined for definite and will depend on a number of factors.

As budgets are tightened, companies' priorities will not always be environmental. However the technology is already here. If requested, a manufacturer can make a forklift with a hydrogen fuel cell, providing the customer has the money to pay for it and the increased operational costs.

Until this happens, forklifts will continue to employ either electric motors or internal combustion engines, although this is not to say that using the same fuels sources means the industry will not be able to reduce its impact on the environment. Greater efficiencies of both engine design and the overall design of the truck can make the most of the fuel that is consumed.

Brand new to the market are Linde's 5 to 8t trucks, which were unveiled at CeMat in May. These trucks are powered by a modern Deutz common rail turbo-diesel engine which surpasses current exhaust emission legislation.

A low-maintenance hydrostatic drive is responsible for transforming the diesel or LPG engine into a precise driving force.The hydraulic lift and tilt functioning are now powered by a Linde developed variable displacement pump, ensuring optimum efficiency as well as improving lift speeds by 30%.

The oil flow of both transmission and mast hydraulics is matched to the required demand, thereby maintaining a low noise level and reducing fuel consumption. Sullivan points out, "The oil lasts longer due to the lower demand, which results in benefits for the environment and keeps maintenance costs down." As for electric powered trucks, the emphasis is on minimising energy consumption to increase shift life. As an example, Sullivan points to the design of Linde's new electric counterbalance range drive axle, which has electronic power modules mounted on the axle rather than at the other end of the truck, which has been the standard design for many years. "This means we can use short power connections conserving up to 8% of total battery energy." Whatever the power source now or in the future, the simplest way to make the most of the power we have is through improved efficiency.

"Whether we are using diesel, electric, bio-fuel, hydrogen or any other fuel source that reaches the market in the coming years, a fundamental means to maximize fuel use is through efficient operation," Bowen concludes. "If one truck is more efficient than another moving pallets, then less power is consumed, fleet numbers can be reduced and this in turn leads to lower costs, fewer emissions and less waste disposal."

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