JCB HIGHLIGHTS HYDROGEN FUTURE

Manufacturers in every industry sector are working towards a zerocarbon future and none more so than construction and agricultural equipment suppliers, as Dan Gilkes reports for Plant & Civil Engineer. With the UK government set to ban the sale of new petrol and diesel cars and vans by 2030, plus heavy trucks by 2040, construction and agricultural markets will also have to play a part in this seismic shift in the way in which machinery is powered. Companies like JCB have already started on what the company calls the Off-Road to Zero, with electric mini excavators and compact wheeled loaders an increasingly common sight at the lighter end of the market. Heavier machinery however, the excavators, loaders and haulers that operate away from urban mains power supply, are not so easy to electrify.

JCB has mastered the art of battery electric operation for compact machinery, but Tim Burnhope, the company’s Chief Innovation and Growth Officer, explained that other solutions will be required for heavier kit.

“We believe there is a real place for electric machines under 4 tonnes and in urban operations,” he said.

The four batteries that power JCB’s electric mini excavator produce 20kW and cost around £8,000. Upscaling that to a 20-tonne machine would require a huge number of batteries, at a cost that would be unacceptable to customers. “Technically you can electrify anything, but it’s not financially viable for the customer,” said Tim. JCB has therefore had to look for alternatives to a battery electric driveline. This includes hydrogen fuel cells and the firm has built 20-tonne excavators with a fuel cell to trial the technology over the last few years. What this research has revealed however, is that a fuel cell is too complex for heavy machinery use and not sturdy enough for prolonged use on site. Alongside the actual fuel cell stack, the machine has to have hydrogen tanks, a DC/DC converter, power electronics, power batteries, motors and inverters.

“The fuel cell excavator is too complicated, not robust enough and too expensive,” added Tim. However, while it may not be an option in combination with a fuel cell, the company believes that hydrogen does have a big future within construction machines. Hydrogen can be transported as a liquid or a gas, carries roughly three times the energy density of diesel and, if created as green hydrogen using renewable energy, it can be a real zero-emission alternative, as the only emission is water.

Developing Technology

JCB, like many of its competitors, has been working hard to improve the efficiency of its diesel engines. From 2010 to 2020, the company managed cut the overall fuel consumption of its equipment lineup by around 50%, through efficiencies within the engine and hydraulic systems. It will continue to develop diesel machines, with the aim of cutting a further 50% of their emissions by 2030. However, while those engines can operate on a variety of alternative fuels, such as hydro-treated vegetable oils (HVO), JCB Chairman Lord Bamford believes that the answer still lies with hydrogen. In July 2020 he set the team at JCB Power Systems a challenge, to make one of its engines run with hydrogen as a fuel by the end of that year. The resulting hydrogen motor bears the initials AB H2 on the cylinder head, which shows his confidence in the technology. The engine block has much in common with JCB’s 444 diesel engine, but the hydrogen unit comes gets a totally new cylinder head and a new combustion system, with much lower injection pressures than for diesel. The fuel is ignited using spark plugs and the engine features a far larger turbocharger, to increase compression of the incoming air. Lord Bamford insisted that the engine had to produce the same power and torque as the firm’s diesel units and operate for just as long between regular services. It also had to fit into existing JCB machinery, with minimal changes. “It is a totally new engine, not a conversion,” said Ryan Ballard, Engineering Director at JCB Power Systems. “Lots of people have tried to do a hydrogen engine, but the problem has been that it’s always been a conversion.”

JCB’s engine plants in Derbyshire and India currently produce 400 engines a day between them and the plan is that the hydrogen engines should be built alongside existing and future diesel models. To meet this requirement, five of JCB’s dynamometer test cells now operate hydrogen engines, rather than dieselpowered motors and hydrogen test engines are rolling off the line, though there is no official date for a machine launch yet.

Hydrogen On Site

So far, JCB has installed the hydrogen engine into its backhoe loaders, Loadall telehandlers and a Fastrac tactor. In each case, the machine looks unchanged, with the engine fitting under the same bonnet. The diesel tanks are replaced by composite hydrogen tanks, operating at 350 bar pressure. The 3CX backhoe uses around 8-10kg of hydrogen to work for a full day, which is easily stored on-board in the space that would have held a diesel tank. Hydrogen is transported in what are called tube trailers, with hydrogen tanks operating at around 700 bar pressure. These can be delivered to a yard or to a construction site. JCB has then designed a Refueller, which is a smaller version of the tube tanker, carrying around 100kg of hydrogen and installed on the back of a Fastrac tractor. The Fastrac is of course also powered by the hydrogen engine. Like a conventional diesel bowser, the Refueller can travel around the site, filling each machine in turn. The hydrogen has a flow rate of 1kg/min, so the Refueller could top-up the backhoe loader in just 6-7 minutes, similar to a diesel machine. “To succeed with larger machinery, we believe that you need to take the fuel to the machine, not take the machine to the fuel,” said Tim Burnhope. By building a hydrogen engine that offers the same power, torque and dimensions as a diesel, JCB would be able to create hydrogen versions of many of its most popular models, with no loss of performance or productivity for customers. With a means to refuel those machines on site, it has also made it much easier for those customers to adopt a hydrogen future. As mentioned, there are no dates for an actual hydrogen machine launch yet. However, with engines now rolling along the production line, that date can’t be too far away. JCB has just taken another big step along the Off-Road to Zero. straight boom excavator