The New Mercedes-Benz GLK-Class - PART VII

The New Mercedes-Benz GLK-Class - PART VII

During normal driving along moderately contoured roads or off-road excursions at low speeds, the system is tuned for soft response to the benefit of the occupants' sense of wellbeing and the vehicle's off-road abilities. At the same time, the driver is assisted by the speed-sensitive power steering that comes as standard in the V6 models and provides the optimum level of steering assistance for the situation in hand. The system therefore makes light work of parking or off-road manoeuvres by maximising power assistance. As the speed increases, however, assistance is reduced in favour of greater directional stability. The precise electrohydraulic steering is used in the GLK 220 CDI 4MATIC. Steering comfort has been further enhanced in both steering variants, thanks to meticulous attention to detail. For instance, the engineers have decoupled the vibrations associated with the airbag module in the steering wheel. Reducing the unsprung masses in the steering system in this way has given steering comfort an additional boost.

Two chassis set-up options are available. If the "off-road styling package" is specified, the GLK comes with longer spring travel and a comparatively softer basic set-up to optimise off-road handling characteristics. Should the customer opt for the "exterior sports package", on the other hand, the specification includes a sports suspension lowered by 20 millimetres with shorter springs, firmer dampers and stronger transverse stabiliser bars. This sharpens the vehicle's driving dynamics for sporty driving without significantly impairing the balanced ride comfort. The road-oriented "exterior sports package" features size 7.5 J x 19 light-alloy wheels with 235/50 R 19 tyres at the front and size 8.5 J x 19 wheels with 255/45 R 19 tyres at the rear. All GLK models are fitted with a tyre pressure loss warning system to ensure potential tyre damage does not have serious consequences. The system detects any sudden drop in tyre pressure and alerts the driver to the situation by flashing up a warning message in the instrument cluster.

The optional tyre pressure monitoring system improves safety yet further. Incorrect tyre pressure or a gradual drop in pressure is indicated by the "Check tyres" warning message; the "Caution Tyre defect" warning appears in the event of a rapid loss of pressure. The tyre pressure monitoring system automatically detects when new tyres or wheels are fitted. The all-new ADAPTIVE BRAKE control system incorporates the basic anti-lock braking system (ABS), acceleration skid control (ASR) and yaw control functions. ABS and ASR monitor and control the driving dynamics along the vehicle's longitudinal axis, while yaw control looks after the lateral dynamics. If ADAPTIVE BRAKE diagnoses critical driving situations, precision application of the brakes and control of drive torque is used to maintain or restore traction and directional stability as far as is physically possible. New additional braking functions make ADAPTIVE BRAKE safer and more convenient. Hill-start assist prevents the vehicle from rolling contrary to the intended direction of travel. The enhanced functionality also includes brake 'priming'.

Should the driver suddenly release the accelerator, the system prepares for possible panic braking by pressing the brake pads lightly against the brake discs. If the brakes are indeed applied with full force, the stopping distance is therefore shortened noticeably by building up pressure the instant the brake pedal is pressed. The GLK also comes with standard-fit adaptive brake lights. The 4MATIC powertrain at the heart of the GLK-Class is one of the most capable all-wheel drive systems on the market, incorporating control systems that set new standards. The basic 45:55 split of drive torque between the front and rear wheels combines with the ESP, ASR and 4ETS dynamic handling control systems to produce supremely assured and perfectly predictable performance. When tuning the control systems, the engineers at the Mercedes-Benz Technology Center (MTC) made a defined level of understeer a priority. All GLK models display these characteristics under all manner of road conditions, come rain or shine, snow, ice or unsurfaced tracks. The newly developed multiple-disc clutch in the centre differential comes to the system's aid when friction between the tyres and ground is particularly low, for example when driving over snow or ice.

A basic interaxle lock of 50 Newton metres gives a major boost to traction - setting the benchmark for vehicles with no additional differential locks without any loss of handling stability. The "off-road" button on the centre console makes GLK models equipped with the off-road engineering package even more assertive in rough terrain. A further switch activates the Downhill Speed Regulation (DSR) system, which automatically maintains a pre-programmed speed between 4 and 18 km/h on steep downhill inclines. The GLK driver can vary the speed at any time during the descent using the cruise control lever. Mercedes-Benz is the only car maker to offer this important equipment detail for off-road motoring. Conventional systems offered by competitors can only maintain the speed programmed at the outset, meaning the speed cannot be altered while the system is in action. A heavy-duty, weight-optimised underguard and underbody protection round off the all-terrain specification of the GLK with off-road engineering package.