Aluminum Range Rover slims down by 420 kg

  • 09-Sep-2012 01:25 EDT
Land Rover (10) RR 8-12.jpg

The fourth-generation, dramatically slimmed down Range Rover leads its ancestors.

The possibility of making a vehicle weight saving equivalent to five male adults is the stuff of dreams for most automotive engineers, but that is what Land Rover has achieved with its new generation Range Rover. The mass-loss figure is 420 kg (926 lb).

Land Rover’s ability to win the automotive equivalent of an Olympic gold medal for slimming is mainly—but not exclusively—down to the shift from steel to an all-aluminum monocoque, itself a world first for an SUV. It is 180 kg (397 lb) or 39% lighter than the previous model’s steel shell and only 12 kg (26 lb) heavier than that of the Mini Countryman. Vehicle curb mass starts from 2160 kg (4762 lb).

But it does not mean that the new car is in any way pared down with regard to equipment. Design boss Gerry McGovern regards it as not only a high-premium SUV but also a high-premium car in its own right.

“The fourth generation Range Rover program started five years ago, and the absolute mission was to develop a completely uncompromised solution with a transformation in efficiency—on and off road—a fantastic opportunity for designers and engineers,” said Vehicle Line Director Nick Rogers.

All new, except for wheel nuts

The only total carry-over from the third-generation Range Rover is, arguably, the wheel nuts. Everything else has been replaced or extensively modified.

Even the manufacturing facility at Solihull has been totally re-equipped as a highly automated, low energy consumption plant, including a new dual-line paint shop.

The car’s aluminum body is riveted and bonded using aerospace engineering processes. On the Solihull body line, 328 robots look after major areas of assembly, including application of 3722 rivets of 17 types. More than 160 m (525 ft) of adhesive is applied. The car uses what is claimed to be the largest single automotive stamping in the world. Saving 3 kg (6.6 lb), the body side eliminates joints to give better structural integrity. The best aerodynamic Cd of the range is 0.34, a 10% improvement, the front grill having active vanes.

Rogers explained that the car has been benchmarked against luxury sedans including the Bentley Flying Spur and Mercedes-Benz S-Class in several areas including noise levels. Although the body is less torsionally rigid than the previous car—24,000 N·m (17,700 lb·ft) per degree compared to 27,000 N·m (19,900 lb·ft) per degree, suspension attachments points are some 30% stiffer.

V6 diesel added

Range Rover customers have demanded less CO2 and improved fuel consumption with no sacrifice in performance on or off road, said Rogers. The TDV6 diesel engine, used for the first time in the Range Rover lineup, has a Honeywell parallel sequential turbocharger. The newly developed 190-kW (255-hp) 3.0-L diesel gives the same performance—0-97 km/h (0-60 mph) in 7.4 s—but with a CO2 saving of 22% at 196 g/km and combined fuel consumption of 7.5 L/100 km.

The diesel V8 (now designated SDV8) is upgraded to achieve 0-97 km/h in 6.5 s, with 229 g/km CO2. A revised TDV8 provides 700 N·m (516 lb·ft) from 1750 to 3000 rpm and has a 9% increase in power to 250 kW (335 hp) and CO2 of 229 g/km.

A 375-kW (503-hp) supercharged V8 gasoline version hits 0-97 km/h in 5.1 s and is restricted to a Vmax of 250 km/h (155 mph).

A diesel hybrid is planned for next year with all batteries and controls under the floor for efficient packaging and low c.g. CO2 for that model will be 170 g/km; 0-97 km/h time is quoted as sub 7 s. No space is lost to the system and the hybrid can do anything on or off road that the conventional models can achieve.

The diesel hybrid version’s modes are all-ICE, electric drive only, or a combination. It has a 1.7-kW·h lithium-ion battery and a 35-kW electric motor. CO2 is 169 g/km; fuel consumption is 6.3 L/100 km; 0-100 km/h takes 7.4 s. 

All Range Rover versions get a new four-post air suspension system complementing a fresh multilink setup at the rear and double wishbones at the front. It is two-channel (independent, front and rear) on some versions. The front subframe is an aluminum extrusion/casting 14 kg (31 lb) lighter than an equivalent steel version, and the rear subframe is a one-piece hollow casting, saving 15 kg (33 lb). The Brembo braking system uses 20-in six-piston calipers with a Bosch control modulator.

Transmission is a ZF eight-speed 8HP 70 with two-speed transfer box.

Off-road capabilities enhanced

The underside of the vehicle is flat. The hybrid gets boron steel protection and can “balance on a rock” without risk of battery damage, according to Land Rover.

All Range Rover versions have a fully automatic terrain response system with manual override. Wading depth is a remarkable 900 to 200 mm (35 to 8 in) more than the old model. Breathers—or gills called Queen Mary funnels—are fitted at the top of the fenders and covered by the closed clamshell hood.

The vehicle's off-road approach angle is 26° at standard ride height or 34.7° at off-road height; departure angle is 24.6° and 29.6° and ramp break is over 20.1° and 28.3°, respectively. Wheel travel is 260 mm (10.2 in) front and 310 mm (12.2 in) rear.

Although it continues a close overall signature and size, now at 4999 mm (196.8 in) long and 2073 mm (81.6 in) wide, the wheelbase is increased by 40 mm (1.6 in) to 2922 mm (115.0 in) to help toward 118 mm (4.6 in) more rear legroom. The roof line is 20 mm (0.8 in) lower. Access is 50 mm (1.9 in) lower and ride height is also 50 mm lower. Maximum ride height for off-road travel is 145 mm (5.7 in).

Interior design includes a 50% reduction in switchgear. There is a choice of seven real wood veneers and three grades of leather.

Two primary hi-res display screens are fitted: a 12.3-in unit for the main instrument pack and an 8-in touchscreen for infotainment with an optional Dual View feature. The Meridian sound system includes up to 29 speakers and a 1700 W Signature Reference installation for 3D surround sound.

The divided tailgate is powered; the top section is of composite material and the lower aluminum and can support two adults—and a Labrador dog.

Aerospace-like aluminum

Land Rover’s Solihull plant now includes what it claims as the largest aluminum bodyshop in the world, with a capacity of 100,000 shells per annum. Up to 50% of the aluminum (supplied by Novelis) is from recycled content. Some 95% of the parts of the Range Rover are recoverable and 85% can be recycled. Over 30% of recycled plastic is used in the car.

Dr. Mark White, Chief Technical Specialist, Body Engineering, said that the bodyshell aluminum is the same gauge and with similar properties to the skin of the Airbus A320: “We have developed some new alloys and moved away from 5000 series to 6000 for formability and ultimate strength reasons.” High strength AC3000 aluminum is used within the crash structure. Rivet-bonding via self-piercing rivets demands about 75% less energy than for conventional spot welding. The body, less doors, takes 3300 rivets.

The car uses 270 pressings and 14 diecastings plus 9 aluminum extrusions. Alloy wheels save about 10 kg (22 lb) per vehicle.

White provided details on the overall 420 kg saved on the vehicle: “We saved about 300 kg via the aluminum body, closures, subframes, and suspension, and 120 kg in the driveline.” The effect is to cut fuel burn by slightly better than 8%. Electric power steering is fitted to all versions of the car. The conventional powertrain Range Rover versions have about 9.1 km (5.7 mi) of cabling.

Quality has been an enduring target throughout the vehicle’s development, with some 40,000 man-hours invested in refining it, stated vehicle designer Andy Wheel. The program also saw "1000 years" of high-performance computing usage, 1.5 million hours of modelling, and over 300 prototypes built. A hundred engineers worked on sign-off of vehicle and systems.

Now the intense program is complete: plainly a weight off the company’s mind.

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