Synergy of sophisticated safety technologies makes new Mercedes models part of the "thinking" process In the new E-Class and S-Class from spring 2009
Mercedes Benz Intelligent Light SystemLEIPZIG, Germany : November 12, 2008 - By introducing around a dozen new or modified systems, Mercedes-Benz is adding a new chapter to its long history of passenger- car safety. Following on from their successes achieved in the domain of occupant protection, the Mercedes experts will be focussing more than ever on avoiding traffic accidents and reducing accident severity, with the driver assistance systems being unveiled in the new E-Class and the model year 2009 S-Class from spring 2009 onwards set to play a crucial role. Mercedes-Benz is implementing a globally unique synergy of sophisticated safety technologies to give its cars extra "senses" and added intelligence. All of which makes Mercedes models part of the "thinking" process – cars that can see, sense and act autonomously. In addition to this, the Mercedes saloons show the way ahead when it comes to occupant protection and set new standards with their "electronic" crumple zones.
Like tried-and-trusted Mercedes inventions such as ABS, ESP®, Brake Assist and PRE-SAFE®, the new assistance systems have been adapted based on real-life accident findings. The aim behind their development was to prevent extremely frequent types of collision and collisions with serious consequences by focussing on the causes of accidents: distance to other vehicles, speed, drowsiness, darkness and lane departure.
To this end, Mercedes-Benz is for the first time using cameras alongside radar sensors. These long-range cameras monitor the area around the car and are able to interpret critical situations. By way of example, new camera-based assistance systems help the driver by keeping the car safely on track, detecting speed-limit signs, controlling the headlamps in line with the current driving situation and enhancing visibility in the dark.
The new E-Class will be the world's first car to feature headlamps that adapt automatically in line with the current driving situation. Adaptive Highbeam Assist detects oncoming vehicles or moving vehicles in front with their lights on and adjusts the headlamps continuously so as to always provide the best possible headlamp range – without dazzling other motorists. In this way, the low-beam range can be increased from its current level of 65 metres to up to 300 metres. If the road ahead is clear, the system switches to high beam with a minimum of fuss. This Mercedes development is therefore fundamentally different to conventional systems of this type, since the latter merely switch between low beam and high beam.
Images : Drive Assistance System
Adaptive Highbeam Assist : selects the optimum light settings automatically
Driving a car at night will be even safer in future. Mercedes-Benz is unveiling an innovative system which adjusts the range of the headlamps automatically based on the distance to oncoming vehicles or moving vehicles in front with their lights on. Consequently, the best possible headlamp range is always selected, allowing the driver to see the course of the road, pedestrians or danger spots at an earlier stage. From spring 2009, the new E-Class and the S-Class will feature the world's most powerful headlamp technology in the shape of the Intelligent Light System and Adaptive Highbeam Assist. What's more, Mercedes-Benz has further developed the tried-and-tested Night View Assist system, which illuminates the road ahead of the vehicle with non-reflective infrared light. As soon as the system detects pedestrians up ahead, they are highlighted on the display in the cockpit.
In contrast to conventional systems, which merely switch between low beam and high beam, the new Adaptive Highbeam Assist system adapts itself in line with the current conditions on the road, controlling the light distribution as the situation allows. The low-beam range can therefore be increased from 65 to up to 300 metres – without dazzling other motorists. If the system detects oncoming vehicles or vehicles in front, it adapts the headlamp range continuously, based on the distance to these vehicles, so that the cone of light emitted by the headlamps ends before it reaches these vehicles. In addition, Adaptive Highbeam Assist takes into account the steering angle in order to dim the headlamps on tight bends. If the road ahead is clear, the system switches to high beam with a minimum of fuss.
Realistic tests confirm that motorists who use Adaptive Highbeam Assist are safer on the road in the dark: dummies placed at the side of the road to simulate
pedestrians were detected from a distance of around 260 metres – around Page 2 150 metres earlier than is the case when conventional low beam is used – despite the presence of oncoming traffic. The new Mercedes assistance system therefore offers more than double the safety at night.
What's more, the system relieves driver stress as there is no longer any need to repeatedly flick the stalk on the steering wheel. So the driver can concentrate more on actually driving the car. Once activated, Adaptive Highbeam Assist always provides the best possible headlamp range.
Studies have shown that high beam is currently only switched on for around eight percent of each night journey on average.
Data transfer every 40 milliseconds
The newly developed Mercedes technology is based on a camera, located on the inside of the windscreen, which monitors the traffic situation in front of the car. Thanks to an intelligent image-processing algorithm, the camera is able to detect other vehicles and the distance to them. The range of the variable-control bi-xenon headlamps is set based on these findings and adapted continuously
depending on the distance to the vehicle in front or the oncoming traffic. The Page 3 system operates at lightning speed, sending new data to the headlamps every 40 milliseconds.
Adaptive Highbeam Assist is ready to act at speeds above 55 km/h and operates autonomously once the driver has moved the rotary light switch to the "Auto" position and selected high beam using the multifunction stalk on the steering wheel.
Intelligent Light System increases headlamp range by 50 metres when driving on the motorway
Mercedes-Benz will combine this new development with the Intelligent Light System, which offers five different bi-xenon light functions, each of which is suited to typical driving or weather conditions:
- Country mode
- Motorway mode
- Enhanced fog lamps
- Active light function
- Cornering light function
Motorway mode, which comes on automatically when driving above 90 km/h, Page 4 increases the driver’s range of vision by up to 60 per cent. This lighting function is activated in two stages: the Intelligent Light System first increases the output of the bi-xenon bulbs from 35 to 38 watts, thereby increasing the light intensity and providing noticeably better illumination of the road ahead and the side verges. The second stage of motorway mode is triggered at 110 km/h, when the beam of the bi-xenon module on the driver’s side is elevated slightly. Motorway mode has a range of around 120 metres, and the driver is able to see about 50 metres further at the centre of this cone of light than with conventional low-beam headlamps.
With the likewise enhanced fog lamps, Mercedes-Benz improves driver orientation when visibility is poor. The new lighting function is activated at speeds below 70 km/h, as soon as the rear fog lamp is switched on. The variable headlamp technology incorporated in the Intelligent Light System makes it possible to pivot the bi-xenon headlamp on the driver’s side outwards by eight degrees, while lowering its beam of light at the same time. This illuminates the inner half of the road more brightly and reduces the degree of glare from light reflected back by the fog.
The Intelligent Light System also includes the active light and cornering light functions. These are switched on automatically: depending on the steering angle, yaw rate and vehicle speed, the active headlamps pivot sideways by up to 15 degrees in fractions of a second, thereby greatly improving road illumination. On an extended bend with a radius of 190 metres, the driver is able to see 25 metres further than with conventional low-beam headlamps thanks to this Page 5 system. This function operates in both low-beam and high-beam mode.
The cornering light function improves safety at crossroads, at T-junctions and on tight bends. It is activated automatically when the driver operates the turn indicators or turns the steering wheel at a speed below 40 km/h. The fog lamps then swivel to illuminate the area diagonally in front of the vehicle for a distance of around 30 metres, with an angle of coverage of 65 degrees.
Images : Adaptive Hi-Beam Assist
Images : Adaptive Highbeam Assist - Intelligent light system
Lane Keeping Assist: warning if the car leaves its lane
Another new assistance system developed by Mercedes can prevent accidents caused by the car leaving its lane. More than a third of all road users killed in Germany are involved in this type of accident. This is why Mercedes-Benz has developed a "forward-looking" system for safe motoring called Lane Keeping Assist. Its camera monitors the line taken by the car and the driver's control inputs on a permanent basis, allowing the system to detect when the car leaves its lane unintentionally and if there is a risk of an accident. If this is the case, the system warns the driver in plenty of time, prompting them to counter-steer by making the steering wheel vibrate with a series of short, clearly discernable pulses.
Unlike conventional systems of this type, the Mercedes assistance system also assesses the driver's actions and, by doing so, can ascertain reliably whether the car has left its lane intentionally or unintentionally. There is therefore no warning if, for example, the driver accelerates before overtaking or joining a motorway, brakes heavily or steers into a bend.
If the system detects that the car is leaving its lane unintentionally, it activates an electric motor in the steering wheel, causing the steering wheel to vibrate. The timing of the warning depends on the width of the road and the type of lane markings. If the car crosses over a continuous line marking on the road, as opposed to a broken line, the system emits its warning earlier.
Images : Lane Keeping Assist
Speed Limit Assist: a camera with an eye for traffic signs
A further new assistance system reminds the driver of the current speed limit in force: the camera on the windscreen detects speed-limit signs as the car drives past them and then indicates the speed limit on the display in the speedometer. The driver therefore remains fully aware of the current speed limit, enabling them to adapt the car's speed accordingly. The display goes out as soon as the speed limit is lifted.
Thanks to the huge strides forward made in image-processing technology, Speed Limit Assist is able to work in real time, analysing the images within a fraction of a second – as the car drives past – and providing the driver with the required information instantaneously. Plus it makes no difference whether the speed-limit sign is at the side of the road or on a gantry above the road.
Furthermore, Speed Limit Assist evaluates the data provided by the navigation system's digital map, allowing it to check the plausibility of the camera image. By way of example, the last speed limit detected disappears from the display as soon as the navigation system detects that the car has entered a built-up area.
Images : Speed Limit Assist
ATTENTION ASSIST: drowsiness detection system fitted as standard in the E-Class and S-Class
Thanks to a new technology, future Mercedes models will have a keen sense of their drivers' awareness. The aim is to detect driver drowsiness in plenty of time so as to warn them before they fall asleep momentarily. According to scientific studies, around a quarter of all serious motorway accidents are caused by driver drowsiness.
The new ATTENTION ASSIST system is equipped with highly sensitive sensors which monitor the driver's behaviour, the current driving situation and over 70 other parameters. By doing this, the system is able to detect when the driver's concentration starts to slip. This permanent form of monitoring is important for detecting the floating transition from awakeness to drowsiness and for warning the driver at an early stage. In addition to the speed, lateral acceleration and longitudinal acceleration, the system also detects use of the turn indicators and pedals as well as certain control inputs and external influences such as side winds or road unevenness, for example.
Observation of steering behaviour has proven to be extremely meaningful. Field tests carried out by the Mercedes engineers over a period of several years, involving over 550 participants to date, show that drowsy drivers make minor steering errors that are often corrected quickly and abruptly. These are detected
by a highly sensitive steering wheel angle sensor. If ATTENTION ASSIST detects Page 5 typical indicators of drowsiness based on these and other data, it warns the driver by emitting an audible signal and flashing up a message on the display: "ATTENTION ASSIST. Break!"
ATTENTION ASSIST will be specified as standard for the new E-Class and the model year 2009 S-Class.
Images : ATTENTION ASSIST
PRE-SAFE®: tensioning of the seat belts before an unavoidable accident
Further standard equipment Mercedes-Benz offers for these models includes the PRE-SAFE® anticipatory occupant protection system. Based on information received from sensors, it identifies situations that might turn into accidents and instinctively activates preventive occupant-protection measures, allowing the seat belts and airbags to deploy with maximum effect in the event of an impact. PRE-SAFE® therefore bridges the gap between active safety and passive safety; it is networked to Brake Assist and the Electronic Stability Program (ESP®), whose sensors recognise potentially dangerous driving situations and then transmit this information to the electronic control units within milliseconds.
In another first, Mercedes-Benz will also be using the information provided by the short-range radar to trigger the seat belt tensioners at the very last moment before an unavoidable collision, thus greatly reducing the forces exerted on the driver and front passenger during the crash.
Radar technology: sensor with medium-range detection capability and greater range
DISTRONIC PLUS and Brake Assist PLUS – Mercedes assistance systems based on sophisticated radar technology – are highly effective at helping to prevent accidents. Analysis of accident-research data has shown that this technology can prevent a fifth of all head-to-tail crashes in Germany on average. On motorways, the accident rate can be reduced by as much as 36 percent.
Mercedes-Benz has further enhanced the radar technology for the new E-Class and the model year 2009 S-Class. The newly developed long-range radar sensor will have a range of 200 metres instead of 150 metres as previously. In addition, the sensor now has medium-range detection capability, allowing monitoring of the area up to around 60 metres ahead of the car with a 60-degree beam width. This new technology enables even more accurate monitoring of the traffic situation in front of the car and even better detection of dynamic events such as a car in front swerving suddenly. The two wide-beam short-range radar sensors (80-degree beam width) with a range of around 30 metres are still employed.
Images : PRE-SAFE®
PRE-SAFE® Brake: autonomous emergency braking as "electronic" crumple zone
As well as warning drivers in the new E-Class and the S-Class of an imminent head-to-tail crash, radar technology can also assist with emergency braking. The sensors are networked with Brake Assist PLUS, which automatically calculates the brake pressure required to prevent an imminent collision. This braking assistance, available as soon as the driver hits the brake pedal, allows controlled, targeted braking or – if necessary – emergency braking, depending on the car's speed and the distance to the vehicle in front.
If the driver fails to react to the warnings given by Brake Assist PLUS, the PRE-SAFE® Brake intervenes and brakes the car autonomously: around
1.6 seconds before the calculated impact point, the system initiates autonomous partial braking and decelerates the car with around 40 percent of the maximum braking power.
In the new E-Class and the model year 2009 S-Class, this safety system provides a further function: if the driver still fails to act after automatic partial braking, the PRE-SAFE® Brake activates the maximum braking power around 0.6 seconds before the now unavoidable impact and, as a consequence, can greatly reduce the severity of the accident. The system therefore acts like an "electronic crumple zone", offering the car occupants even greater protection.
Occupant protection: over 150 crash tests for the highest possible level of Mercedes safety
During the course of its development to date, the new E-Class has successfully come through over 150 high-speed crash tests and more than 17,000 realistic crash simulations, including around 40 different crash tests which the saloon had to pass in order to gain world-wide approval and nine extremely demanding, in-house impact tests, some of which go well beyond the statutory requirements.
The Sindelfingen-based engineers have continued to perfect the crumple-zone principle invented by Mercedes safety pioneer Béla Barényi. The front deformation zones of the latest Mercedes passengers cars work on several levels – making them even more effective as the impact forces are distributed over a wide area and can be made to bypass the passenger cell. Likewise the increased use of ultra-high-strength steel alloys helps the bodyshell to withstand high impact loads. These steel grades offer maximum strength whilst minimising weight. Around 72 percent of all the bodyshell panels for the new E-Class are made from sophisticated high-tech steel grades – a new record in passenger-car development.
With a total of seven airbags fitted as standard, not to mention seat-belt tensioners, belt force limiters and NECK-PRO crash-responsive head restraints, the new E-Class will offer an even more extensive package of safety equipment than its predecessor. Self-adaptive belt-force limiters in the rear, which adapt automatically to suit the size of the rear passengers, will be introduced for the first time in autumn 2009.
Images : PRE-SAFE® Brake
Images : PRE-SAFE® Brake - with out PRE-SAFE® Brake
Images : PRE-SAFE® Brake - with PRE-SAFE® Brake
Pedestrian protection: new E-Class with active bonnet fitted as standard
Mercedes-Benz is continuing its long-standing and very successful commitment to protecting those road users who are most at risk. Standard equipment for the new E-Class includes an active bonnet, which greatly reduces the risk of injury to pedestrians. In the event of an accident, a system of springs raises the rear section of the bonnet by 50 millimetres within milliseconds, thus enlarging the deformation zone. One special feature of this Mercedes system is its reversibility: drivers can reset the active bonnet themselves without having to visit a workshop.
Images : Pedestrian protection
Night View Assist PLUS with new function for highlighting pedestrians on the display
Mercedes-Benz will be offering Night View Assist – available for the S-Class since 2005 – for the new E-Class. The system uses infrared technology to enhance the driver's range of vision in the dark: two separate headlamps illuminate the road with invisible, non-reflective infrared light. A windscreen-mounted camera designed to pick up precisely this type of light records what happens in front of the car and sends the image to a display on the dashboard. The clear, needle-sharp greyscale image that appears here shows the scene in front of the car, allowing the driver to see pedestrians, cyclists or obstacles on the road at an early stage.
The Sindelfingen-based engineers have further developed Night View Assist and, in future, will be equipping it with a special pedestrian-detection function: as soon as the system detects pedestrians ahead of the car, they are highlighted on the display to make it easier for the driver to see them.
Images : Night View Assist PLUS
Blind Spot Assist : Radar sensors monitor the areas directly alongside and behind the car
Blind Spot Assist, developed by Mercedes-Benz, uses radar technology to monitor the areas directly alongside and behind the car. It warns the driver when changing lanes would be too dangerous.
Every year, around 9,500 serious road accidents in Germany are caused by motorists who fail to take heed of the traffic behind when changing lanes or cut across in front of another vehicle too soon after overtaking.
The Mercedes assistance system can help drivers to change lanes safely: short-range radar sensors housed on both sides of the rear bumper monitor the areas directly alongside and behind the car. This process enables them to see if there is another vehicle in the next lane – in the so-called blind spot. In such situations, the system informs the driver by illuminating a red warning signal in the glass of the exterior mirror. If the driver fails to see this warning and indicates to change lanes, a warning signal sounds as well.
Images : Blind Spot Assist
DISTRONIC PLUS/Brake Assist PLUS Radar-based assistance systems can prevent 20 percent of all head-to-tail crashes
DISTRONIC PLUS and Brake Assist PLUS – Mercedes assistance systems based on sophisticated radar technology – are highly effective at helping to prevent accidents. This is one of the findings of an analysis carried out by Mercedes-Benz based on representative accident-research data. This technology can prevent a fifth of all head-to-tail crashes in Germany alone. On motorways, the accident rate can be reduced by as much as around 36 percent. Mercedes-Benz has further enhanced the radar technology for the new E-Class and the model year 2009 S-Class.
Every year in Germany there are over 50,000 serious head-to-tail crashes, in which some 5700 people are either killed or seriously injured. One in six traffic accidents in which people are injured is down to a head-to-tail crash. The situation is even more serious in the US, where this type of collision accounts for around 30 percent of all serious road accidents.
In developing the DISTRONIC PLUS and Brake Assist PLUS radar-based assistance systems, which have been available for the S-Class since 2005 and the CL-Class since 2006, Mercedes-Benz has made an important contribution towards preventing head-to-tail crashes. This is one of the findings of the latest accident research carried out at Mercedes, based on the reconstruction of over 800 head-to¬tail crashes. The representative study focussed on one question in particular: how many accidents of this type could be prevented if all passenger cars were equipped with this Mercedes technology?
The results confirm the considerable safety-enhancing effect of the assistance systems: DISTRONIC PLUS and Brake Assist PLUS prevent over 20 percent of head-to-tail crashes on average. In another quarter of these collisions, the systems can help to greatly reduce accident severity. This combination of state-of-the-art
Daimler Communications, 70546 Stuttgart, Germany Mercedes-Benz – A Daimler Brand radar and brake technology offers the greatest safety potential on motorways, Page 2 where around 36 percent of all head-to-tail crashes can be prevented.
Warns and assists the driver as well as providing emergency braking
DISTRONIC PLUS proximity control operates at speeds of between 0 and 200 km/h: it keeps the car a set distance behind the vehicle in front, applies the brakes as required and can even bring the car to a complete halt, depending on the traffic situation. If the gap to the vehicle in front narrows too quickly, the system gives the driver an audible warning and, as soon as this first warning signal sounds, automatically calculates the brake pressure required to prevent a collision in this situation.
This technology helps the driver to gauge the level of risk and makes the calculated brake boosting force available instantly, even if the driver does not press the brake pedal forcefully enough. Brake Assist PLUS allows controlled, targeted braking and, if necessary, increases the braking force right up to the point at which an emergency stop is performed, depending on the road speed and the distance to the vehicle in front.
Radar sensors and camera: range of up to 500 metres.
Daimler Communications, 70546 Stuttgart, Germany Mercedes-Benz - A Daimler Brand New radar sensor with extended range and medium-range detection capability
When a potential accident situation is recognised, assistance is provided courtesy of two short-range radar sensors behind the front bumper and a long-range radar in the radiator grille. Mercedes-Benz has further enhanced the performance capability of these sensors. In the new E-Class and model year 2009 S-Class, Mercedes-Benz uses a newly developed sensor with a range of 200 metres – instead of 150 metres, as previously – for the long-range radar. In addition, the sensor now also has medium-range detection capability, allowing monitoring of the area up to around 60 metres ahead of the car with a 60-degree beam width. This new technology enables even more precise monitoring of the traffic situation in front of the car and even better detection of dynamic events such as a car in front swerving suddenly. The two wide-beam short-range radar sensors (80-degree beam width) with a range of around 30 metres are still employed.
40 percent of all S-Class saloons are equipped with radar
Mercedes-Benz offers DISTRONIC PLUS in combination with Brake Assist PLUS as an optional extra. Around 40 percent of customers buying new S-Class models in Germany specify this safety technology; in the case of the CL-Class, over 70 percent of customers order DISTRONIC PLUS and Brake Assist PLUS. Since 2005, Mercedes-Benz has supplied customers with over 50,000 cars featuring these innovative systems.
Daimler Communications, 70546 Stuttgart, Germany Mercedes-Benz - A Daimler Brand
Images : Distronic PLUS
Occupant protection : The crumple zone protects the occupants on four levels in the event of a frontal impact
Mercedes engineers have continued to perfect the idea patented by their mentor Béla Barényi – through a programme of accident research, crash tests and computer simulations. And with the new E-Class, they have created another masterpiece of passenger-car safety technology. The saloon's front deformation zone works on several levels – making it even more effective as the impact forces are distributed over a wide area and can be made to bypass the passenger cell, With seven airbags fitted as standard, not to mention seat-belt tensioners, belt force limiters and NECK-PRO crash-responsive head restraints, the new E-Class offers an even more extensive package of safety equipment than its predecessor. Adaptive belt force limiters will be installed in the rear for the first time (optional extra).
The pioneering work carried out by Béla Barényi enabled Mercedes-Benz to develop the basic principles of passenger-car safety in the 1940s and 1950s. And these principles still apply to this day. Barényi's ideas first came to fruition in the "Ponton" (three-box body) Mercedes (model series W 120) exactly 55 years ago in autumn 1953. This precursor to the E-Class was the world's first car to feature a crash-stable floor assembly, which enhanced occupant safety in the event of a frontal or side impact.
This car's successor – model series W 110/111/112 with the distinctive tail fins – provided the next milestone in the field of safety technology. From 1959 onwards, these saloons were the first models into which Mercedes-Benz incorporated front and rear crumple zones. In the event of an accident, these zones absorb energy in a predetermined manner and distribute the impact forces, thus greatly reducing the forces exerted on the occupants.
This Mercedes concept for the safety body still forms the basis for passive safety today; it is part of all modern-day passenger cars, not just those made by Mercedes-Benz.
Béla Barényi's successors at the Mercedes-Benz Technology Centre in Sindel¬fingen have continued to further develop the concepts devised by their mentor, based on the latest development and calculation methods and the use of state-of¬the-art bodyshell materials. The extent of their dedication has reached a new pinnacle with the new E-Class. During the course of its several years of development to date, the saloon has successfully come through over 150 crash tests and more than 17,000 realistic crash test simulations, including around 40 different crash tests which the saloon had to pass in order to gain world-wide approval and nine extremely demanding, in-house impact tests, some of which go well beyond the statutory requirements. Only cars that pass these tests receive the highest accolade in automotive safety: the Mercedes star.
The results of the crash tests prove that Mercedes has pulled off yet another masterstroke in the field of occupant safety.
Large deformation zones are capable of absorbing high forces in the event of an accident
Compared to the previous model series, the Mercedes engineers have enlarged the deformation zones substantially in the front and rear sections as well as improving the energy flows. The front crumple zone has four independently acting impact levels, meaning that the forces can be distributed over a wide area while bypassing the passenger cell.
1) Sectional panels above the wheel arches form the upper side-member level. From here, the impact forces are channelled into the A-pillars and, subsequently, into the roof frame.
2) An aluminium crossmember connects the forward-extended side members and ensures that the forces are transferred to the side facing
away from the impact. The crossmember and the forward-extended side members form the central impact zone.
3) The integral support to which the engine, steering and front axle are attached also serves as an impact level in the event of a frontal collision. It is made of high-strength steel and has been connected to the newly developed floor side members by means of special supporting tubes. As a consequence, the integral support can deform in a predetermined manner and absorb energy in the event of a crash on the one hand and channel high impact forces straight into the vehicle floor on the other.
4) The side skirts have been extended forwards to support the wheel and prevent it from entering the footwell in the event of an offset frontal collision. This design also allows the wheel to absorb some of the crash energy. In order to provide specifically targeted front-wheel support and location, Mercedes-Benz has also developed special struts and additional energy-absorbing elements in the wheel arches. The struts are arranged diagonally and prevent the passenger cell from sinking in the event of an impact.
The firewall is a four-part construction. This design enables Mercedes engineers to vary the material thickness according to the level of vulnerability in an accident. As the load acting on the firewall during a frontal crash is greatest in the lower section, the sheet steel used here is more than twice as thick.
Around 72 percent of all the body parts are made from high-strength steel
Key aspects of the safety concept at the heart of the new E-Class include intelligent design and meticulous material selection. More so than ever before, Mercedes-Benz has given preference to ultra-high-strength steel alloys because they offer maximum strength whilst minimising weight and, therefore, are essential for meeting strict Mercedes safety and durability requirements. Around 72 percent of all the bodyshell panels for the new E-Class are made from these grades of steel – a new record in passenger-car development. These ultra-high-strength, high-tech alloys, which boast three to four times the tensile strength of conventional steel grades, account for around eight percent of the weight. They are used at points where the material can be subjected to very high stresses during an accident – as a material for the B-pillars and roof frame to provide side impact protection, for example, or at the rear to produce a robust crossmember.
If these sophisticated alloys were not used, far more material would be required in order to meet the stringent safety requirements. The B-pillar is a perfect case in point: the body components which have to absorb high forces and transfer these to the body structure in the event of a side impact consist of sheet-metal shells plus an extensive reinforcement which reaches as far as the upper edge of the belt deflector. One of the shells and the reinforcement are made from ultra-high¬strength, hot-formed steel. Were they made using conventional sheet steel, however, the B-pillars would be more than a third heavier. In other words, the ultra-high-strength, high-tech alloy enhances safety whilst also reducing weight.
Custom-designed floor panels form the robust backbone of the passenger cell
The passenger cell of the new E-Class proves to be a structure which is virtually immune to deformation and which keeps the passengers' survival space intact, even at high impact speeds, regardless of whether the collision is head-on, from the rear or from the side, or whether the vehicle rolls over. The use of high-strength steel and thicker panels plays as important a role here as the installation of additional load-bearing members.
The main floor assembly consists of different sheet-metal plates that either undergo flexible rolling or are welded together by laser beam and subsequently shaped. Flexible means that the ultra-high-strength steel can be processed in such a way that areas with different steel thicknesses can be produced within a single component. The middle blank forms the tunnel – the actual backbone of the passenger cell. Here the thickness of the custom-designed panels varies between 1.4 and 2.0 millimetres, depending on the stresses and loads to which they are subjected.
Other new features which are very important for both occupant protection and the rigidity of the bodyshell include the continuous floor side members, the insides of which are further reinforced with extra sections. Their front faces connect to the side members, thereby lengthening the load-bearing paths along which forces can be distributed in the event of an impact. At the rear, the floor side members extend as far as the crossmember beneath the rear seat unit to stabilise the entire floor structure.
The Mercedes engineers have also incorporated sturdy aluminium transverse sections – known as transmission tunnel braces – into the floor assembly. One is located beneath the transmission, and is designed to direct forces to the opposite side of the vehicle during a lateral impact. The second creates a connection between the two side members. It likewise braces the floor assembly and is able to channel impact forces into the floor structure at an early stage in the event of a side-on collision.
The rear structure has successfully passed the toughest of crash tests
Multi-piece side members and a robust, flexible crossmember made from ultra¬high-strength steel form the key components of the rear-end structure. The rear side members are continuous, closed box sections with carefully graduated material thicknesses. These are able to absorb high forces, thereby making a decisive contribution to occupant safety in the event of a rear impact. The bolt-on flexible crossmember is manufactured using a flexible rolling process which likewise allows the material thickness to be varied as required. Accordingly, the material thickness on the outside of the crossmember – where impact loads are highest – is greater than on the inside.
The new E-Class also meets the world’s most stringent crash regulations where rear impact protection is concerned, for example the 80-km/h test in the US.
The restraint system for the E-Class includes seven airbags as standard With seven airbags fitted as standard, not to mention seat-belt tensioners, belt-force limiters and NECK-PRO crash-responsive head restraints, the new E-Class offers an even more extensive package of safety equipment than its predecessor. The airbags, which deploy in a matter of milliseconds in the event of an accident, include two adaptive airbags (for the driver and front passenger), a kneebag for the driver, two sidebags in the front-seat backrests and two large windowbags which extend from the A-pillar to the C-pillar during a side impact. Rear sidebags can be ordered as optional extras.
Three-point inertia-reel seat belts with belt tensioners and belt-force limiters are fitted as standard for the driver, the front passenger and the occupants of the outer seats in the rear. Force limitation is performed on an adaptive basis in the front: after reaching a certain maximum retention, the belt force is reduced to a lower level – the belts are allowed to slacken so that the occupants can sink deeper into the airbags as they deploy, reducing the strain exerted on the torso.
Rear belt-force limiters that adapt to the size of the passengers
From autumn 2009, Mercedes-Benz will be offering adaptive belt-force limiters for the rear seats as an option for the first time. These belt-force limiters adapt to the size of the rear passengers automatically. The newly developed system detects whether the rear occupant is large or small as soon as the seat belt is put on, based on the length of the pulled-out seat belt, and adapts its mode of operation accordingly. The maximum restraint force is activated immediately if the rear passenger is large in size. Only once a certain time has elapsed does the limiter reduce the force. In the case of smaller occupants, the force exerted by the belt is set to a lower level and is not increased continuously until the crash is actually taking place. Hence the protective effect of the seat belt can be adjusted, i.e. further optimised, in line with the occupant's body size.
Crash-responsive head restraints reduce the risk of whiplash injuries NECK-PRO is the name Mercedes-Benz has given to a crash-responsive head restraint whose development, like that of PRE-SAFE® and other Mercedes innovations, is based on analyses of real accidents. NECK-PRO is an effective means of reducing the risk of whiplash injuries during a rear-end collision. If the sensor system detects a rear-end collision with a defined impact severity, it releases pre-tensioned springs inside the head restraints, causing the head restraints to move forward by about 40 millimetres and upwards by 30 millimetres within a matter of milliseconds. This means that the heads of the driver and front passenger are supported at an early stage.
Images : Occupant protection
Images : Digital Crash Test System
Images : Child Safety
[Source : DAIMLER]
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