The new Mercedes-Benz GLK 2012: Active safety - Assistance systems take the GLK to the top of its market segment

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Assistance systems familiar from the S- and E-Class feature as standard to enable an improvement in active safety and driver-fitness safety and take the compact SUV to the top of its market segment. Electric steering with STEER CONTROL as standard, which supports the driver in unstable driving conditions by triggering an impulse which can be felt on the steering wheel, prompting countersteering by the driver in the correct direction.

Brake Assist (BAS), which provides additional brake power when emergency braking is detected, and ADAPTIVE BRAKE featuring Hill-Start Assist, HOLD function, brake drying in the wet and priming of the brake system when emergency braking is detected all support the driver. The high standard of active safety is ensured by the AGILITY CONTROL suspension with selective damping system, the ESP® Electronic Stability Program with integrated trailer stabilisation and tyre pressure loss warning and, on the 4MATIC models, by permanent all-wheel drive and the 4ETS electronic traction system.

Optional equipment includes the ATTENTION ASSIST drowsiness detection system or the PRE-SAFE® anticipatory safety system. Additional assistance systems, including active variants, are optionally available. One example here is Active Parking Assist, enabling automatic manoeuvring into and out of parking spaces. To facilitate manoeuvring when visibility is poor there is a backup camera with guide lines or – for the first time from Mercedes-Benz – a 360° camera. This feature uses image information from four cameras in the front and rear areas and in the exterior mirror housing to generate a bird's eye view of the vehicle and its surroundings. The undistorted image is presented in real time on the central COMAND display. In addition to the functions of the backup camera, it also enables monitoring of the areas to the side of the vehicle and in front of the vehicle, thus helping to avoid inadvertent collisions during manoeuvring. Guide lines provide additional assistance, the 360° camera marking the vehicle's movement range according to the steering wheel angle.

Additional systems are optionally available as individual items or in special packages. The Driving Assistance package Plus comprises DISTRONIC PLUS including BAS PLUS, PRE-SAFE® Brake, Active Lane Keeping Assist and Active Blind Spot Assist. The Parking package combines the described 360° camera including Active Parking Assist for automatic manoeuvring in and out of parking spaces and PARKTRONIC. The Lane Tracking package includes Lane Keeping Assist and Blind Spot Assist.

The right direction: recommendations from STEER CONTROL

The facelift provides the GLK with electromechanically assisted direct steering. This configuration employs a variable steering ratio which becomes noticeably more direct as the steering wheel angle increases. This provides the driver with better feedback from the road and reduces the necessary steering work. In turn, this results in improved handling and agility. The electric steering system additionally offers speed-sensitive power assistance, providing for enhanced steering comfort throughout the entire speed range.

The standard-fit STEER CONTROL system becomes active when the assistance systems have diagnosed unstable driving conditions which can be alleviated by simple steering movements. To this end, an appropriate level of steering wheel torque is determined on the steering wheel in accordance with the given driving conditions and duly set by the electric steering assist system. In case of oversteering – with the rear end of the vehicle pushing towards the edge of the turn in the road – STEER CONTROL prompts the driver to steer in the opposite direction until the vehicle regains stability. Correspondingly, in case of understeering – with the front end of the vehicle pushing towards the edge of the turn – the driver is prompted to increase the steering wheel angle. The system can also help to compensate yaw when the GLK brakes on a road surface offering different levels of friction on the right and left, e.g. on winter roads which are covered in ice on one side. STEER CONTROL then prompts the driver to turn the steering wheel in the appropriate direction to compensate the yaw.

Even if the driver ignores STEER CONTROL's recommendations, sufficient reserves remain available to stabilise the vehicle with the dynamic handling control systems such as ADAPTIVE BRAKE, ESP® or 4ETS. STEER CONTROL always supports the driver in an "advisory" role, never overruling them.

Stability pact: AGILITY CONTROL – suspension with selective damping system

With the AGILITY CONTROL suspension the GLK demonstrates a high standard of flexibility and is able to resolve the conflict between the different aims pursued in designing SUV suspensions: on the one hand, chassis and suspension engineers seek to create a vehicle which is sporty and agile while at the same time offering a comfortable and soft ride and also performing well on off-road terrain. When the onus is on sporty, adaptive handling, the springs and above all the shock absorbers require a certain hardness. This, in turn, rules out the desired suspension comfort which is typical of the brand and imposes restrictions on off-road capabilities. If the vehicle is fitted with softer dampers in pursuit of suspension comfort and off-road performance, this will naturally diminish the driving dynamics. "Stroke-dependent damping" provides a way out here. The shock absorber is configured such that its cushioning forces are applied in a flexible manner. During normal driving over moderately contoured roads or on slow cross-country trips the system responds in soft mode, to the benefit of the occupants' wellbeing and the vehicle's off-road performance. In order to ensure that this wellbeing is also maintained when the driver adopts a bolder style or in abrupt evasive manoeuvres, the dampers then switch to a harder mode to provide for a high level of driving stability in such situations.

To avoid any unpleasant consequences in the event of tyre damage, all GLK models incorporate a tyre pressure loss warning system. This system detects sudden pressure losses in a tyre and triggers a corresponding warning in the instrument cluster. Tyre pressure monitoring is optionally available to further improve safety in this area. Incorrect tyre pressure or "creeping" pressure losses are indicated by the warning "Check tyres", while rapid pressure losses trigger the message "Caution Tyre malfunction". The tyre pressure monitoring system identifies newly fitted wheels automatically.

"Offroad Engineering package" enables superior off-road performance

The Offroad Engineering package continues to be available, ensuring that the vehicle is well able to assert itself away from paved roads with Downhill Speed Regulation (DSR), off-road driving programme (adaptation of transmission shift points and accelerator characteristic), tough underguard and a raised suspension.

When the "Offroad Engineering package" is on board, the so-called "off-road switch" in the centre console enhances the GLK's capabilities in difficult terrain. At the touch of a button a special drive programme is started which varies the shift points of the 7G-TRONIC, "softens" the accelerator characteristics and activates the ESP® off-road functions with off-road ABS and a special off-road 4ETS system. Engine control intervention is subsequently reduced and the system additionally permits higher wheel slip values. This control strategy improves off-road traction in particular on surfaces offering low friction levels, such as sand, gravel or rubble. The GLK's off-road ABS was premiered in the current M-Class. It identifies the most diverse ground conditions via the continuous comparison of wheel slip models. This results in the best possible deceleration strategies for off-road trips on rock, sand, rubble, gravel or slush.

In this equipment variant with Offroad Engineering package, is provided with a manual drive programme (M) in which the individual gears can be selected via paddles on the multifunction steering wheel. This operating mode guarantees maximum off-road driving enjoyment. An additional switch activates Downhill Speed Regulation (DSR), which automatically maintains a preset speed between 4 and 18 km/h on steep downhill stretches. The driver is able to vary the speed at any time by means of the cruise control lever.

The ground clearance of 210 millimetres and the minimal body overhangs (824 mm at the front, 957 mm at the rear) results in an approach angle of 23 degrees and a departure angle of 25 degrees; the ramp angle stands at 19 degrees. The GLK is able to negotiate gradients of up to 70 percent; the maximum angle of inclination is 35 degrees. Together with the relatively compact wheelbase of 2755 millimetres and the comparatively low vehicle weight, this ensures that the GLK is able to make good progress even in topographically difficult terrain.

Offroad Light for better off-road visibility

When travelling at low speeds in confusing off-road terrain, the broadest and brightest possible illumination of the area in front of the vehicle is expedient to enable more effective and faster recognition of obstacles. As for the GL, a special Offroad Light is thus also available for the new GLK in conjunction with the Offroad Engineering package and the Intelligent Light System (ILS). The Offroad Light goes on automatically when the driver activates the Offroad drive programme while the headlamps are on. To this end, the bi-xenon headlamp modules pan outwards by 6 degrees, the luminous power of the xenon burner is increased by 3 W and a symmetrical light distribution is set. In addition, the LED cornering lights on both sides are switched to permanently lit mode, while dynamic curve illumination and range adjustment are deactivated. These settings ensure broader and brighter illumination of the area directly in front of the vehicle in comparison to ILS, which is optimised for on-road use, enabling any obstacles to be recognised more quickly.

The Offroad Light is active up to a speed of 50 km/h. Upon the driver dropping below this threshold, the ILS automatically reactivates the light functions which are optimised for on-road use.

Credits: Daimler AG

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