The New Generation Jaguar XK XK8 And XKR | Part Four

The Latest Technology - Electronic Driver Aids

A car with the power and performance potential of the new-generation Jaguar XK deserves the best in mechanical and electronic driver safety aids – and this car gets them. Features including Dynamic Stability Control (DSC), Emergency Brake Assist (EBA), and Jaguar’s Computer Active Technology Suspension (CATS) system are all standard (CATS optional on XK8). Also standard on every new-generation XK model is Jaguar’s Adaptive Restraint Technology System (A.R.T.S.), which is universally acknowledged as a major advance in passive vehicle safety.

CATS: Computer Active Technology Suspension

First among these is Jaguar’s Computer Active Technology Suspension system, CATS – further enhanced, and standard on the XKR as well as being available as an option on the XK8. This is an electronic control system which combines uprated springs to increase roll stiffness with adaptive dampers to optimise ride refinement – again delivering the blend of driving dynamics with comfort and refinement that is a Jaguar hallmark. This sophisticated technology allows the XK to be two kinds of car in one package – a true sports car, but with the comfort of a luxury grand tourer. In simple terms, CATS works by continuously adjusting the damping characteristics to suit driving conditions, optimising both ride and handling. A series of sensors provide information to the electronic control unit, which is mapped to deliver the best solution to dampers that can switch between firm and soft settings in milliseconds. When the car is started, damping defaults to the firm setting, but switches to the softer setting once the car is travelling at more than 5mph (8kp/h) on a smooth, straight road. When the XK encounters bumps, or during cornering and braking, the settings switch instantaneously to the firmer mode, reducing roll and increasing stability.

DSC: Dynamic Stability Control

Dynamic Stability Control is one of the XK’s front-line electronic safety features. It is not a substitute for careful and considered driving, but it does allow performance potential to be responsibly explored, with a powerfully reassuring back-up.

This active system enhances safety at the car’s limits of grip and roadholding, which is especially valuable when road conditions are poor. Unless it is manually switched off (in which case a warning light in the dashboard will remind the driver that they are travelling without DSC) the system operates automatically whenever the engine is running. A warning light also flashes when the system is intervening to restore stability.

A series of sensors detect specific kinds of motion and send information to the Electronic Control Unit (ECU), which in turn activates a hydraulic modulator that interacts with the braking system. The sensors detect the speed of each wheel (and more importantly their relative speeds) for both the ABS and DSC systems; monitor the steering angle at the steering wheel rim (inputs of as little as one-and-a-half degrees or about 5mm of wheel movement can be detected); measure yaw rate, which is the rate of rotation of the vehicle about a vertical axis and indicates that it is understeering at the front or oversteering at the rear; lateral acceleration – the sideways cornering force – and also measure hydraulic brake pressure, to interpret whether or not the brakes are being applied.

Essentially, the system uses the steering wheel angle to interpret the direction in which the driver intends the car to go and compares that with the direction actually taken by the vehicle. If the onset of instability – either understeer or oversteer – is recognised, the system takes measures to restore stability, either by reducing engine torque via the ECU, selectively applying gentle braking to one or more wheels, or both. Working with the drive-by-wire throttle and the ABS system, it will make corrections to enable the car to follow the driver’s steering input. If the driver tries to keep the throttle open the DSC will reduce the power anyway and if the driver does not apply brake pressure, DSC will. The system also intervenes to prevent wheelspin, again by automatically reducing power and if necessary braking individual wheels.

DSC does not discourage a driver from enjoying the full abilities of the XK's highly developed chassis; rather it allows the car to be driven enjoyably, but with a safety net. Controlling wheelspin can actually improve acceleration, especially on surfaces with uneven grip. And because it can be switched off, the wheelspin-controlling element of DSC will not leave the driver stranded in special circumstances, such as when snow chains are fitted, or when trying to drive out of deep, soft snow or sand.

If the system has been switched off and the sensors detect an emergency situation, DSC will automatically re-engage as soon as the brakes are applied. What's more, the DSC system is tuned specifically to match the characteristics of the XK. The manner in which it makes corrections depends on the problem it is correcting. If the car oversteers in a left-hand corner, for example, (with the tail sliding outwards) DSC will apply the right-front brake to provide a corrective effect. If the car understeers in a left-hand corner (with the nose pushing wide) it will apply the left-rear brake to help turn into the corner. If the problems are caused by too much power being applied, DSC will reduce power.

EBA: Emergency Brake Assist

Research shows that even in emergency situations most drivers do not apply the maximum possible braking pressure. This prevents those drivers from entering the 'ABS zone', the area of maximum braking efficiency immediately prior to the point where the wheels lock and the anti-lock function comes into action. Jaguar's Emergency Brake Assist (EBA) system is designed to overcome this. When EBA detects a rapid application of the brake pedal it interprets it as an emergency braking situation and automatically applies the additional pressure that the driver has not provided, producing maximum braking effort. Not only that, but it does so more quickly than the driver could. This can dramatically cut braking distance, with obvious safety benefits.

Cruise Control And Adaptive Cruise Control

Cruise Control is now standard on the XK, and Adaptive Cruise Control (ACC) is an option across the range. Cruise Control is already a familiar feature, allowing the driver to set a chosen speed, which the car will then maintain with no input from the driver’s feet. Cruise Control maintains constant speed by adjusting the throttle (and if necessary by automatically shifting to a more suitable gear). It is immediately overridden by touching the brakes, or the cancel button, but the previously set speed can be resumed by touching the resume button.

ACC, which Jaguar introduced as an option on the previous XKR, takes the function of cruise control an important step further. ACC detects slower vehicles ahead, or can sense another vehicle crossing into ‘your’ lane. If this happens, speed is adjusted to suit, overriding the set cruise speed to maintain the gap and removing the need for the driver to adjust or cancel the set speed.

ACC uses microwave radar technology to sense slowing traffic and then interacts with the throttle (and if necessary the brakes) to select an appropriate speed. Jaguar’s system, which makes many more individual measurements on each horizontal radar scan than other systems, displays the set speed permanently in the instrument panel. If the sensors are obscured (by mud or snow, perhaps) a ‘Sensor Blocked’ message appears, warning the driver.

A further development of the innovative ACC technology is Forward Alert, which provides an audible warning of slowing traffic ahead, but unlike ACC, does not reduce the throttle or apply the brakes. System sensitivity can be set to a preferred range, which is indicated in a dashboard display.

A.R.T.S. : Adaptive Restraint Technology System

Jaguar’s world-leading Adaptive Restraint Technology System (A.R.T.S.) is standard on all XK models and is a major advance in passive safety systems. The previous XK introduced the world’s first ultrasonic occupant sensing system, which employs ultrasonic technology and a seat weight sensor to detect the presence, position and size of a front seat passenger. This information is used to determine airbag energy levels most appropriate to that occupant during a frontal crash. If the front passenger seat is unoccupied, that airbag will not deploy in the event of an accident.

The occupant sensing part of the system works by using ultrasonic signals to determine the position of a front-seat passenger’s head and upper body in relation to the front airbag position. Four ultrasonic sensors are located in the A- and B-pillars and in a modified roof console. If the passenger is too close to the fascia, a warning light will show that the system would restrict deployment of the airbag. When the passenger is far enough away the airbag becomes available again and the light goes out.

"We are committed to world-leading safety and communications technologies that further strengthen the appeal of Jaguar’s highly successful sports coupes and convertibles." Dr Nick Barter, Director Of Product Development

A.R.T.S. communicates through a central processor and uses all its information to control whether the two-stage airbags are deployed at all, or inflated fully or only partially. If the front airbags are deployed, they will be inflated fully or partially depending on the severity of the impact and the data from ultrasonic occupant sensing. In a severe impact the airbags will be deployed with full force. In other circumstances, for example a low-speed collision and with a smaller front-seat occupant in the car, the airbag will not inflate with full force because it does not need to, and because doing so could actually be more hazardous. That means that in every case the XK airbags provide the maximum level of appropriate protection, but not so much ‘protection’ as may be harmful.

Convenience As Well As Safety

The XK continues to offer heated 12-way electrically adjustable driver and front passenger seats. As standard on both XK8 and XKR, the steering column is electrically adjustable through a wide range of positions, for both reach and rake. The column position is included in the two driver seat-memory settings, and also includes the switchable option of an automatic ‘entry and exit’ mode. Steering wheel multi-function controls incorporate cruise control, audio and telephone controls. In the convertible, the fully trimmed and snug fitting hood, with heated glass rear window, operates at the touch of a single button, from open to closed, or vice versa, in 20 seconds – even when the car is moving, at speeds of up to 10mph.

Appearance And Options

Some of the visual changes to the new XK are to bring its badging into line with the rest of the Jaguar range while underlining its position at the top of that range. Uniquely for the XK there are new sculpted Jaguar ‘growler’ badges and a new ‘leaping cat’ emblem on the airbag door and other interior components. There is a prominent new ‘R’ logo on the supercharged models, which carry the ‘Jaguar Supercharged’ badge on their nose. The XKR also has distinctive bonnet louvres, fine-mesh grille, and the ‘R’ logo appears on the XKR gearknob, which also has alloy side inserts in the leather covering.

In the areas where the XK has changed most obviously, it has changed for reasons of improved function and practicality. New headlight details, with black rather than chrome recesses around the powerful Xenon lights, feature on the XKR. The finisher above the XKR rear number plate is now body-coloured.

New Wheels

Three new alloy wheel designs are added to the wide choice already available for each variation of new XK. The R Performance optional wheels are made by performance wheel specialists BBS, and feature two-piece modular construction with die-cast and spun rims and titanium screws, one of which neatly conceals the tyre valve. The full range includes 17-, 18-, 19- and 20-inch wheels. The new additions are the 17-inch Gemini styles, which becomes standard equipment on the naturally aspirated coupe and convertible, the optional 18-inch Centaur and the 18-inch Hydra, which is new for the XKR. A wide choice of other styles is available, the most extreme option remaining the 20-inch BBS alloy wheel with ultra low profile Pirelli PZero tyres.

New Headlights

As well as being an unmistakable styling signature for the XK, the car’s shapely headlights have more to them than meets the eye. Light sensors detect low ambient light, and in Autolamp mode the sensors automatically turn on the sidelights and low beam headlights when outside light levels drop. On the new XK, turning on the wipers for more than 20 seconds automatically turns on the headlights when in Autolamp mode. The XKR has high-intensity Xenon headlights, the blue-white discharge light providing measurably greater intensity than that of a halogen bulb. The XKR’s lights also feature automatic levelling and power wash as standard, and similar Xenon lights and the power-wash system are available as an option on the XK8. The power-wash feature uses powerful nozzles, integrated into the light units, to blast dirt from the lenses. Inside the XKR headlight shell, the areas surrounding the reflectors are now finished in black rather than chrome. A button on the key fob allows the headlights to be turned on for 25 seconds from outside the car, to aid a driver approaching a parked car in the dark.

New Colours And Trim

Four new exterior colours – Adriatic Blue, Jaguar Racing Green, Ebony and Midnight – replace four of the existing paint colours, and there is a range of new interior trim options. Adriatic Blue is a metallic, rich mid-to-dark blue; Jaguar Racing Green is a distinctive darker metallic green that shows lighter undertones under strong light; Ebony is a pure, solid black; and Midnight is a dark, deep and metallic black.

The new interior trim options, with beautifully stitched full leather seat facings, include both single colour andcontrast options, from a sophisticated pallete. The choice now includes full Cranberry or Heritage Tan upholstery, or Ivory and Warm Charcoal. Dove is added to the traditional Cashmere, and there is a choice of five multi-layer canvas hood colours – Black, Blue, Green and Light and Dark Beiges. A choice of hand-finished wood veneers includes traditional burr walnut or sporty, grey-stained birds-eye maple, while steering wheel options include colour-keyed wood-and-leather, or all leather from the R Performance options range. All XKs, not only the XKR, now include the performance option of specially shaped Recaro sports seats trimmed in soft grain leather and available in three colours, and the Aluminium Pack. This comprises alloy instrument bezels, J-Gate surround, door release levers, pedal pads and tread plates. New domed finishers on the centres of each dashboard needle give a sense of even deeper quality in the classic analogue dials.

New Options

New for the 2003 model year XK is the option of a built-in compass display for the self-dimming electrochromatic interior mirror, while the body-coloured exterior mirrors are power-adjustable and heated. The latest DVD-based satellite navigation options include new navigation discs for an extended range of European countries, including Spain and Portugal and Sweden and Denmark, and also adds Canada to the USA disc. The start-up display includes an analogue-style clock, very much in keeping with Jaguar style.

"The XK is a car for individuals. From a superb starting point of one of the finest luxury sports cars in the world,you can create the car that you want." Lawrence Thomas, XK Brand Manager

The XK looks after driver and passengers. Audio choices begin with the Premium Sound Alpine system, with 320 watts of audio power, nine speakers (eight in the convertible) and a six-disc CD autochanger, boot-mounted for security. It also offers the option of a dual-band telephone, mounted in the centre armrest and with its own touchpad or steering wheel controls. Also for security, all XKs have as standard drive-away door and boot locking, and a ‘valet-key’ locking system to isolate boot and interior storage.

R Performance Options

For the sportiest XKs of all – or the sportiest XK drivers – the R Performance range offers a series of options for all models. These include not only the ‘Aluminium Pack’, comprising instrument bezels, J-Gate surround, door release levers, pedal pads and tread plates, but also all-leather steering wheel rims and gearshift knobs, and a choice of BBS wheels. The R Performance Handling Pack (coupe only) provides a revised, sportier set-up for the CATS Computer Active Suspension System (with uprated springs and anti-roll bars, a lower ride height and retuned steering assistance) plus 20-inch wheels with ultra-low profile tyres, backed by the top specification Brembo brakes.

XK8 or XKR, coupe or convertible, the latest generation of the XK offers everything it ever did – and now even more.

Published 9 August 2002 Melanie Carter
 
 

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