Article
Articles, Issue 49 - Summer 2013

Lightweight Future

A look at Jaguar Land Rover’s success with aluminium.

Having just posted pre-tax profits of GBP 1,675 million, up 11% over last year, and announced an investment programme of GBP 2.75 billion, with a view to introducing eight new or refreshed products this year alone, it’s challenging to recall that this is the same business that went cap in hand, unsuccessfully, to the Blair government for a  bailout loan at the height of the global financial crisis in 2009.

Every press release that Jaguar Land Rover (JLR) issues seems only to trumpet yet another success, whether that be riding high in the JD Power reports that place it second only to that paragon of automotive manufacturing excellence, Lexus, or announcing manufacturing plans in China or a GBP 500 million engine plant in the UK. Jaguar, Land Rover and Range Rover, it seems, can do no wrong.

Customers are flocking to all three marques in their droves, eschewing the global ubiquity of Germany’s three premier brands for a more exclusive club membership. But, underlining the design leadership of Ian Callum for Jaguar and Gerry McGovern at Land Rover there is an engineering ethos in the intelligent use of lightweight materials, specifically aluminium, that one could argue is at least equal to, and they would say privately, better than their rivals.

JLR’s expertise in aluminium and, specifically, Jaguar’s dates back to its time as part of the Ford empire and its Aluminium Intensive Vehicle (AIV) programme of the 1990s. In addition to the development work on aluminium monocoques that Ford had carried out in its own AIV and P2000 programmes, Jaguar also had its own reasons for going down the path it chose, rather than producing a spaceframe structure similar to Audis. It did not want to appear to be a ‘me too’ company following in the German’s tracks.

Jaguar’s breakthrough with the technology underpinned the 2003 XJ, but the saloon’s conservative styling overshadowed the undoubted excellent use of aluminium structures. It really wasn’t until the much sportier, and more contemporary looking, XK arrived two years later that Jaguar’s pre-eminence in employing aluminium to minimise weight was truly noticed.

But there’s much more to the use of this lightweight material than just minimising body-in-white mass and, of course, it shouldn’t be forgotten that Land Rover pioneered the use of aluminium as far back as 1948 with the original Defender built from aluminium recycled from war time aeroplanes at Solihull.

For Mark White, JLR’s chief technical specialist body structures, aluminium body structures are the outward face of a new, greener, more efficient manufacturing process that stretches right across the supply chain: “Our sustainability strategy is not just focussed on the product itself, but parts manufacturing and in the plant and through our suppliers, real total lifecycle approach,” and that applies equally to both Jaguar and Land Rover products.

Talking at the latest Range Rover launch, White explained that “there’s a 72% increase in the amount of sustainable materials recycled over the current car, right across the whole vehicle.”

He stresses sustainability and the environmental challenge. “We didn’t set out by saying it had to be that, but we wanted to make the car not only appeal to the customer from a driving point of view but, also, really wanted to improve the credentials of Range Rover as a vehicle and a brand in terms of its sustainability and its outward face in terms of facing up to the environmental challenge. And we made every effort we could in all areas of the car to make it more sustainable.

“We can’t just pretend the carbon problem doesn’t exist, we have to face up to that and address it in a holistic way. We want to give our customers the type of car they want to drive, we don’t want to make Fiat 500s we want to make Range Rovers but we want to make Range Rovers that are truly environmentally friendly.”

This strategy equally applies to Jaguar products such as the new F-Type built at Castle Bromwich, Jaguar’s fastest and most modern production facility. Because no welding is involved there’s a 70% saving in the amount of energy required if it had been resistant spot welded. It also means that because it’s a very clean process, the body-in-white assembly can share the same facility as trim to give a very connected manufacturing process with quicker feedback during production.

Moreover, up to 50% of the metal used on the F- type is recycled, and that uses only about a tenth of the energy that prime metal requires to give the F-Type one of the lowest carbon footprints of any sports car. That’s the same target JLR set for themselves with both the latest Range Rover and XJ saloon, but the group has ambitious plans to increase that to 75% recycled metal by 2020. “That’s a big walk for us,” says White, adding “we’re working on various projects that are in pilot or research phase that will allow us to do that and the great thing is that our main supplier, Novelis has said that it’s up for the challenge and has publicly stated that its goal is to get from 75 to 80 percent recycled metal supplied to us. They’re on the journey as well and working with us.”

That strategy is equally applicable to suppliers like Walsall pressings, Sertec and Stadco who need to recycle their aluminium to put even more reprocessed metal into the loop. “We’ve tried to apply the same mentality and rigour to the supply chain as we have done to ourselves. We’ve asked all of our suppliers to adopt the same joining technologies, to look at recycling the scrap they produce and make sure they’ve got closed loop recycling in their factories, and making sure they minimise their waste wherever [it occurs] in their part of the production phase,” White explains.

JLR’s three latest products, the Range Rover, Range Rover Sport and F-Type represent the latest stage in the evolution of its lightweight strategy, says White.

“In the past we focussed on saving body weight, I think now we’re into saving weight on the whole vehicle so the obvious thing to do was to look at the sub-frames, corner geometry, knuckles, wishbones and look at how much weight we can save on them. With the added advantage that the more unsprung mass/weight you save the better it is from a dynamics point of view.

“The sub-frames are now a combination of extrusions and castings, using multi-process approach. We tried to look at how much integration opportunity can we get from using those type of materials.”

As both the Range Rover Sport and F-Type share the same production facilities as their siblings, the Range Rover and XK, respectively, it would be easy to assume there is a high percentage of shared parts, but that would be wrong.

According to the Sport’s chief programme engineer, Stuart Frith, there’s a 75% part count difference with the Range Rover. The most obvious are the body panels, but from an attribute perspective there are stiffer engine mounts, re-tooled suspension to deliver an eight mm lower ride height, a new magnesium front carrier that allows a lower bonnet height but still delivers Euro NCAP 5 pedestrian impact as well as a multi CAN system replacing the Range Rover’s twin CAN arrangement. Both are produced at Land Rover’s all-new body shop at Solihull, part of a GBP 370 million investment in the site which also includes a new paint shop. With a potential 120,000 a year capacity running three shifts there’s plenty of scope for expansion to include Land Rover’s burgeoning model line up that will include a radical upgrade of the Discovery which, inevitably, will follow the aluminium path at some point in the future.

Speculation would also have it that the much-rumoured Jaguar cross-over would also be assembled at Solihull, but that has been dismissed by global brand director, Adrian Hallmark. “There are bigger and more logical segments for Jaguar to be in than cross-overs, that could be years away,” he says.

Whilst the F-Type shares its production facilities with the XK, it too, is a significantly different beast to the larger GT says director, Jaguar programmes, Ian Hoban. “From a structural platform perspective we refer to this as the fourth generation of our aluminium architecture so to say it’s an evolution from XK is not accurate. Since the original XJ back in 2002 we’ve been developing and refining the architecture and the bottom line is how much stiffness can you get out of the structure in key areas for a given weight?

As with the Sport, the F-Type differs significantly from the XK resulting in a 10% increase in torsional stiffness over and above the XK RS. “The best example is the work we’ve done around the structural castings, nodes” explains Hoban, “so the front suspension mounts the ‘A’ post castings, the base of the ‘A’ posts and ‘B’ posts castings as they’re really the foundations around which the body is built. We measure it in frequency and degree per load as well. The frequency is also about measuring the noise paths back into the structure at a more specific point in the vehicle from NVH point of view.”

“As important, are the front suspension mounts and we’ve increased the lateral stiffness between those two mounts by 30% over the XK RS and that’s important because when you couple that with suspension knuckles that are 24% stiffer than the XK RS, it results in probably the stiffest open sports car on the market.”

However the challenge that Jaguar has with the F-Type, is that production is constrained at Castle Bromwich, not just in terms of manufacturing capacity, but also shift patterns. This will be addressed according to JLR’s chief executive officer, Dr Ralf Speth: “Castle Bromwich is the next stage of investment for Jaguar. The first stage of the plan is to fill both plants and then long term build all Jaguar Land Rover models in all plants.”

That leaves plenty of scope for forthcoming models like the Audi A4-BMW 3-Series challenger due in 2015. This, too, will employ aluminium structures that will be further developed for the next generation XF models.

The Volkswagen Group with its MQB, MLB and MSB strategy has already shown the way in which clever application of dimensions combined with a plug and play range of powertrains and key components such as heating, ventilating and air-conditioning systems, can not only drive down costs to improve profitability, but also allow product planners the luxury of developing vehicles for narrow niches that might otherwise be only marginally profitable.

“Our goal is to make aluminium so affordable that it’s a no-brainer to make everything out of lightweight materials. Not only that, but to make a lightweight car for the same cost as a steel car, to minimise the cost to JLR and maximise the benefits for the customer in terms of fuel efficiency and CO2, combined with using 75% recycled aluminium by 2020,” says Mark White. Combine that with innovative powertrains, class leading styling, plus an enthusiastic work force and the prospects for Jaguar and Land Rover look more positive than ever before.

Writer: Ian Adcock

About lotusproactive

Lotus proActive is an e-magazine published quarterly by Lotus Engineering, covering engineering articles, industry news and articles from within Group Lotus (Cars, Engineering, Originals and Racing).

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