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Fork lift truck manufacturers have invested heavily in finding alternatives to internal combustion and battery power, and a lot of them are already available. Bob Hine, technical consultant to BITA, says the European Commission is now homing in on two key emission issues that are creating challenges for lift truck designers – noise and exhaust emissions, which affect engine powered trucks, and waste disposal, which he says is all too often overlooked.

“Waste disposal is a significant challenge to a designer considering lift truck maintenance intervals, since it affects the amount of engine and hydraulic oil that is changed over the whole life of the equipment.

“Designers will make increasing use of after-treatments to tackle exhaust emissions. While the fundamental technologies related to catalysts and diesel particulate filters are well established, designers now face the additional challenge of minimising increased noise resulting from increased cooling.”

Hine also reckons engine management systems will continue to become more sophisticated, increasing the rigorous monitoring of engine performance to ensure optimum efficiency, while reducing fuel consumption and emissions.

He points to the use of bio-hydraulic oils, which can double the life of mineral oils, with changes extending from 3000 hours to 6000 hours – reducing waste disposal. “Oil-conditioning monitoring, particularly on large truck fleets, can also be cost-effective.”

Last year Jungheinrich invested several million Euros into developing greener products and technology. Spokesman Craig Johnson says: “We are aware of the need to develop technology that will outlast reserves of traditional fuels and are funding research into technologies such as methanol and hydrogen fuel cells.

“These are big challenges and involve tackling issues such as developing supply chains for alternative fuels and creating safe operating environments.”

In the meantime, Jungheinrich is working on getting the most out of the technologies it already has, such as its electric motor batteries. “We are working to lower their operating temperature to prolong their life and develop more efficient transfer to the motor,” says Johnson. “This means fewer battery changes, more work done and less energy needed for charging, resulting in financial and environmental savings.”

The company has also developed an energy-saving technology similar to that used for hybrid engines in the automotive industry. This AC technology kicks in on battery-powered trucks every time a driver brakes or lowers the forks. It then reclaims any excess energy and uses it to charge the battery. “Around 25 per cent of the energy needed during typical operation is reclaimed during braking and lowering by using our motors as an alternator,” says Johnson.

Jungheinrich’s VFG engine-powered 4 Series hydrostatic range, which features Volkswagen engines, have been designed to offer low noise levels and emissions, while returning particularly low fuel consumption.

“Test cycles have shown that over the course of 2000 hours of typical operation the truck can save around £1000 in fuel costs compared with a standard conventional converter counterbalance truck. This could provide significant savings for companies running a large forklift fleet,” says Johnson.

In terms of the volume of pollution created, the forklift industry is relatively small fish, compared to the automotive industry. The matter of which green technology will be the favourite in the future will be a matter for the automotive industry to decide. So forklift manufacturers will be keeping a beady eye out for any changes in that direction. Manufacturers that spread across both industries, such as Nissan, well be placed.

David Bowen of Linde Materials Handling, says green technologies are, at present, focusing mainly in the area of alternative fuels for engine trucks, such as compressed natural gas (CNG), bio-diesel, bio-ethanol, bio-methane, and sun diesel.

“But 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.”

But whether hydrogen will dominate as the primary clean energy carrier of the future is yet to be decided.

Brendon Sparks, Nissan’s director for Industrial Machinery, says it’s now a question of waiting to see if hydrogen is the way to go. “We remember the hoo-hah that surrounded CNG when it was released a few years back, only to find it then died a quiet death.”

Fuel cell technology still has certain teething problems regarding its commercial viability.

For starters, Bowen says the predicted lifespan of a fuel cell is rated at 5,000 operating hours – 1,500 less than that of a conventional electric truck. Fuel cells are also much more costly than conventional batteries – the average price of a fuel cell being around four times the price of a conventional battery.

There are other technical issues such as the fact that they draw a lot of current. For example, a reach truck needs a large amount of current to provide it with enough energy to lift pallets high. “This type of truck actually uses more energy than a motor car once it has been started up,” says Bowen.

Another difficulty is that a fuel cell is lighter than a conventional lead battery. “For a car, having a lighter fuel source is good, but not for a forklift truck. The lost weight would have to be added elsewhere, especially with counterbalance trucks,” says Bowen, “manufacturers would either have to increase the length of the truck or lessen the amount it could load.

“With tight budgets, companies tend to opt for the cheaper prices at the expense of environmental issues.” The technology is already here. If requested, a manufacturer can make it, providing the customer has the money to pay for it. But it needs a bigger mass market to take it on seriously; to create the volumes needed to make it commercially and economically viable – to push up production and bring down cost. “It needs a bigger industry than ours to invest in it,” says Bowen.

This will no doubt have an impact on the take up of fuel cell technology, “but if fuel cells become a big part of the automotive industry, this will put pressure on the materials handling industry to take it up,” says Bowen.

Like many manufacturers Linde has prototypes in operation. Bowen reckons: “The only true constraint is the lack of an economically priced supply of hydrogen gas or fuel cells.”

Nissan has also invested a lot in developing green technologies, and its latest design – the DX Eco range, which boasts a 99 per cent emissions reduction – will be launched in May.

The truck is fitted with its Tri-Cat system, which is designed to address the three main noxious gases that are emitted from LPG engines. Sparks says Nissan is the only manufacturer to fit this type of system to its LPG trucks as standard.

It also comprises a three-way catalytic converter and an engine management system, which ensures fuel is used on a demand-only basis, to help maximise fuel savings.

Anthony Nadalin, Toyota Material Handling Europe’s product marketing manager, says it is working to develop clean energy trucks, improve fuel efficiency, and achieve cleaner/ reduced exhaust emissions. It is also planning to improve the recyclability of its trucks, and explore new fuel technologies.

Linde uses industrial engines based on automotive designs for its volume engine trucks. “This gives us immediate access to improvements in design prompted by changes to emissions legislation for motor vehicles around the world,” says Bowen.

Linde’s hydrostatic transmissions help control the use of engine power. It doesn’t have a differential type drive axle – around eight per cent of engine power is lost driving the differential gears of a conventional torque converter transmission. “As we can convert more engine power to power at the wheels, we can keep the engine revs needed to complete a task to a lower max limit, which helps reduce consumption and emissions.

“Also we have automatic engine speed control where engine revs are automatically matched to the operator’s demand for hydraulic performance. This avoids the heavy over-revving usually associated with conventional trucks with torque converter transmissions further reducing consumption/emissions.”

Bowen says for electric-powered trucks, Linde is working on minimising energy consumption to increase shift life. As an example Bowen points to the design of its new electric counterbalance range drive axle, which has electronic power modules mounted on the axle rather than, 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.” The new design of mast on the X range reach truck is lighter and consumes less energy per work cycle than a conventional mast. There is also a trend towards high frequency chargers as a result of the reduction in mains electricity consumed to recharge the battery.

Linde’s sister company Still has been developing hybrid technology since the mid eighties. Since then it has refined the original diesel-electric truck to the RX70 range of diesel and LPG-fuelled forklifts, scooping the Fork Lift Truck Association’s Environment Award earlier this year for its RX70 25-35 IC engine counterbalance truck.

The RX70 hybrid drive uses an engine (either diesel or LPG), to drive the generator, which in turn drives an electric induction motor – this then provides power to the drive wheels and all of the truck’s systems.

The RX70 25 2.5 tonne forklift uses 2.5 litres of diesel per hour of operation, whereas a traditional torque converter truck can use up to 5.4 litres per hour. It also features a variable displacement hydraulic pump which helps prolong the life of the hydraulic oil.

This low consumption means a modern combustion engine/electrical drive system can be used, based on hybrid technology, that is intelligent drive control for rpm reduction with uniform driving conditions and a hydraulic control that acts demand-compliantly.

Diesel particulate filters and computer-controlled catalytic converters are available as equipment options for all RX 70 stackers. The drive system has enabled it to double servicing intervals for the stacker. So the transmission oil no longer has to be changed and the service life of the engine oil and of the hydraulic oil has been doubled, which contributes to the conservation of natural resources and to the avoidance of waste.

Mitsubishi reached the finals of the FLTA’s environmental awards with its FD80-160N diesel counterbalance truck. This uses common rail technology and an electronically controlled fuel injection system, a turbo charger, an intercooler, exhaust gas recirculation and a positive crank case ventilation system – to generate high torque but low noise, emissions and fuel consumption.


Moffett, the company which invented truck-mounted forklifts, has designed its machines to run on eco-friendly bio fuels as well as conventional diesel. The company promises that the Kubota engine which is used for all the company’s trucks, delivers the same performance. All Moffett trucks are also recyclable.

Bob Hine of BITA, says one of the most valuable steps for operators looking to make forklift operations more environmentally friendly, is monitoring lift truck activity using ‘on board’ data logging equipment. This records the different ways in which the truck is used over time, for example traction, lifting/lowering, whether the operator’s in place but truck is stationary, or whether it is parked.

“Provided data is collected and analysed by experienced staff, capable of relating results to business activity, this form of monitoring can help plan changes in materials handling movements,” he says.

“By smoothing out peaks and troughs of lift truck use during 24/7 operations, operators will invariably save fuel through reduced operation, thereby reducing cost and making an environmental contribution through fewer carbon emissions.”

If a truck is constantly being driven at high speed, with a lot of braking and acceleration, it’s bound to use more energy. Terry Foreman, general manager of Mitsubishi Forklift Trucks, says: “If you limit your acceleration and top speed to 75 per cent or even 70 per cent of the truck’s potential you will make significant energy savings. The resulting loss of productivity, meanwhile, will be 5 per cent at most.

“Programming the power level down in this way, can cut energy consumption by 20 per cent – and that makes longer shifts possible. Or another way you can take advantage of that reduced consumption is by fitting a smaller, less expensive battery and discharging it more efficiently to its 20 per cent residual capacity. This will extend the life of your batteries and keep them working at high performance levels for longer.”

David Bowen of Linde says: “If you’re planning on taking steps to make forklift operations more environmentally friendly, involve forklift truck suppliers as early as possible and be prepared to look in detail at technical features and listen to, and compare technical arguments rather than just encourage a sprint to the lowest price. Make the environment a key factor in your selection process but don’t just blindly believe what you are told.”

Mark Hignett, founder of Loadmac, which specialises in truck-mounted forklifts, and former managing director of Moffett, says: “Making forklift trucks green has made commercial sense for a long time. It’s only over the last 18 months that it’s become somewhat of a fashion.”

He reckons one of the next steps will be for manufacturers to cut down the energy used during production.

“This has been the focus of legislation and best practice for some time – for example, moving from solvent based paints to powder coating, using methods to cut steel parts that use less energy, and changing from corrosion protection processes that form a cold chemical corrosion barrier rather than a hot metal ‘skin’.”

One of the biggest areas for environmental improvement is the maintenance and operating end of the business. “Professional and regular maintenance of forklifts in service reduces the amount of parts used to keep the machine working throughout its life.”

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