Car Design News: All New Land Rover Freelander 2: In Depth

Page 1 Overview
Page 2 Powertrain
Page 3 Interior-Exterior
Page 4 Safety
Page 5 Special Features
Page 6 Tech specs

SPECIAL FEATURES

DRIVING DYNAMICS

�The all-new Freelander 2 has been engineered to inspire driver confidence and passenger comfort over a wide variety of conditions and surfaces, from sporty on-road driving to off-road mud-plugging. Our goal was to create a driving experience that felt just as good to someone trading up from a conventional saloon as it did to an experienced 4x4 specialist.� Mike Cross, chief engineer, vehicle integrity.

The Land Rover engineers� objectives for the driving dynamics of Freelander 2 were to combine on-road behaviour that is agile, predictable and refined, with class-leading off-road ability. Their comprehensive approach started with the design of the base suspension system, and was supplemented by innovative technologies such as an intelligent 4x4 system, Land Rover�s patented Terrain Response, and sophisticated traction and stability systems. Key contributors to achieving excellent on-road performance were the new, fully independent suspension system � coil-sprung struts front and rear � and an exceptionally stiff body using front and rear sub-frames. Front and rear anti-roll bars provide excellent anti-roll control.

The responsive rack-and-pinion steering is direct and fluid, with just 2.6 turns lock-to-lock. Rigidly mounted to the front sub-frame to improve lateral stiffness, the steering is adjustable for reach and rake.

�The Freelander 2 is a revelation on-road,� says Land Rover�s chief engineer, vehicle integrity, Mike Cross. �Some sporty 4x4s are more firmly sprung, but where Freelander 2 really scores is in its mix of agility, responsiveness and ride comfort. It is never harsh, but is always a rewarding and predictable vehicle to drive hard.�

On-road ride comfort has been a key consideration, and Freelander 2 surpasses many compact premium saloons � let alone rival 4x4s � due to its supple long-travel suspension, its excellent torsional body stiffness, its isolated (rubber-mounted) front and rear sub-frames, and its large-diameter gas damper struts.

Off-road it is a class-leader. Its capability starts with 210 mm (minimum) of ground clearance to overcome rocky, sandy, rutted or muddy terrain. This also helps Freelander 2 to wade through water up to 500 mm deep � better than most rivals. Approach and departure angles are also excellent.

Full-Time Intelligent 4x4 System

An innovative full-time intelligent 4x4 transmission is fundamental to delivering Freelander 2�s class-leading breadth of capability. Its front-rear torque split varies continuously to suit dynamic conditions. Only a small amount of torque is fed to the rear wheels under normal conditions, such as on a straight tarmac road, but in tough off-road situations, almost all the engine torque can be fed to the rear wheels, if required. This is an ideal arrangement that always offers maximum grip in difficult conditions, yet minimises rear drive � and therefore rotational losses and, in turn, fuel consumption � when not required.

�The torque balance adapts continuously,� says chief programme engineer Andrew Foster. �So, for example, if you encounter mud or snow on the road, torque distribution between front and rear can be adjusted, to give you optimal traction and primary safety at all times.�

The intelligent 4x4 system has been developed in conjunction with Haldex, whose acclaimed centre-coupling technology continuously alters the front-rear torque split, normally through a hydraulically operated multi-plate wet clutch. However, Land Rover wanted an electronically controlled centre coupling � linking the propshaft to the rear differential � that could pre-engage at rest to reduce wheelspin from standing starts, engage quickly when traction loss was detected and disengage quickly without compromising stability control systems. The system also had to transmit the necessary torque to achieve Freelander 2�s off-road traction demands.

The result is used exclusively on Freelander 2, and proactively engages full-time 4x4 rapidly and completely. A new high-pressure pre-charge pump charges the hydraulic system as soon as the engine is started, allowing for full-time 4x4 from rest. It also reduces the time taken to achieve full torque once wheel-slip has been detected � within 15 degrees of wheel-slip rotation (compared with over 60 degrees of wheel-slip rotation with more conventional units).

The Freelander 2�s Haldex unit is designed to allow up to 1500 Nm of torque transmission. An accumulator also speeds up the unit�s response. Full torque transmission can be achieved in just 150 milliseconds. In effect, the new Haldex coupling gives the proactive engagement benefits of full-time 4x4 and the efficiency and fuel economy of an on-demand system. Representing the best of both worlds, it is ideal for a compact 4x4 such as Freelander 2.

Terrain Response Enhances Go-Anywhere Ability

Terrain Response is one of the core Land Rover technologies that gives the Freelander 2 its outstanding breadth of capability. Standard on all but the entry model, it adapts the responses of the vehicle�s engine, gearbox, centre coupling and chassis systems to match the demands of the terrain. It optimises driveability and comfort, as well as maximising traction.

On the Freelander 2, there are four Terrain Response settings which the driver can choose via a rotary control:

General Driving � provides a broad span of ability suitable for most on-road driving and easier off-road conditions
Grass/Gravel/Snow � for slippery conditions, on-road or off-road
Mud and Ruts
Sand

�Each of the settings optimises Freelander 2�s suite of electronic and mechanical controls to suit the chosen terrain,� says Andrew Foster. �It�s like having an off-road expert to assist.�

Terrain Response also controls the following range of stability and traction aids:

Dynamic Stability Control (DSC): is designed to help stop torque to a wheel after loss of traction, but in some off-road situations torque feed is still desirable, even when traction is being lost. Terrain Response automatically adjusts the DSC so that appropriate torque is maintained.
Electronic Traction Control and Anti-lock Brakes: these slip and braking control systems are all adjusted and tuned by Terrain Response to offer optimum grip, braking power and safety on the chosen terrain.
Hill Descent Control (HDC): the latest generation of the award-winning Land Rover technology that automatically restricts speed downhill, using the anti-lock brakes, and improves driver control on slippery descents. HDC is automatically engaged on appropriate Terrain Response programmes. Downhill speed rates vary according to which surface is selected.

Terrain Response also changes the setting of the electronic centre coupling, to optimise 4x4 drive in tough conditions. It works continuously, and made its production debut in the Land Rover Discovery 3 in 2004.

Large and Powerful Brakes

The Freelander 2 has large vented discs front and rear, providing stopping power comparable to that of a good compact sports saloon. The large front discs � 316 mm on the petrol model, 300 mm on the diesel � are �reverse vented�, so they draw cool air into the disc over the central bell, which is then vented out from the rim of the disc. This approach improves thermal stability under severe braking. Rear brake discs are also substantial � 302 mm in diameter, for both diesel and petrol. The handbrake is a drum-in-disc device featuring two shoes per wheel. This achieves superior hill-hold performance compared with conventional disc-only systems.

The electronic modulator at the heart of the stability control systems on Freelander 2 constantly monitors and, if necessary, adjusts both braking and engine traction to ensure the driver maintains control of each wheel. As well as reducing brake pressure, as in a conventional anti-lock (ABS) braking system, the modulator is designed to help generate positive hydraulic pressure to increase braking force in an emergency.

In addition to the latest-generation four-channel anti-lock brakes, the modulator also controls Electronic Brakeforce Distribution (EBD), which balances the distribution of braking force between front and rear, Emergency Brake Assist (EBA), which boosts pedal pressure when full braking is required, and Corner Brake Control (CBC), which enhances rear-end stability when braking in corners. It also helps to control the Hill Descent Control, Electronic Traction Control and Dynamic Stability Control systems.

Roll Stability Control

Roll Stability Control is the most sophisticated roll-over prevention technology ever fitted to a Land Rover. Gyroscopic sensing allows this system � linked to the electronic modulator � to compare the rate of change of body roll angle with the steered course. If necessary, incremental brake force is applied at the outer wheels, widening the turn radius to help prevent the roll.

Gradient Release Control

Another innovation which makes its debut on Freelander 2 is Land Rover�s patented Gradient Release Control system. Linked to the Hill Descent Control, this system ensures that, when releasing the brakes on extremely steep hills, brake-line pressure is released progressively, helping to maintain full driver control.

Wheels and Tyres

Freelander 2 is available with a wide variety of wheels and tyres, ranging from 16-inch to 19-inch diameter. All are specifically tuned to help deliver Land Rover�s class-leading breadth of capability.

The wheels are all low-pressure die-cast aluminium, and rim width is wider than normal. All tyres are all-terrain rated, so they perform well both on-road and off. All run at 32 psi (2.2 bar), irrespective of size, load or speed, which simplifies life for the customer. The smallest tyre offered � on the diesel only � is a chunky 215/75R16 tyre, while the biggest � aimed at those who want sports saloon levels of responsiveness on-road � is a 235/55R19 (accessory fit only).

Towing Capability

Freelander 2�s powerful engines, strong body and 4x4 transmission make it an ideal tow vehicle. The petrol automatic and diesel manual models are able to tow a 2000 kg braked trailer � which is more than the vehicle�s kerb weight � making them suitable for most single horseboxes, medium-sized caravans and many boats. The diesel automatic can tow up to 1750 kg.