2010 Mercedes-Benz ESF Safety Vehicle

Mercedes-Benz ESF 2009 Safety Vehicle Makes U.S. Debut at Washington, D.C. Auto Show

Making its Ú.S. debut at the 2010 Washington, D.C. Auto Show, open to the public January 27-31, the innovative Mercedes-Benz ESF 2009 is showcasing the future of automotive safety. The ESF 2009 (Experimental Safety Vehicle 2009) provides a sneak peak into what Mercedes-Benz safety specialists are currently developing - with a time horizon extending well into the future. A pioneer in automotive safety, Mercedes-Benz recently celebrated several anniversaries in this field: in August 1939 the safety pioneer Béla Barényi started his work in Sindelfingen. He invented, for example, the principle of the crumple zone, a trailblazing innovation which entered series production at Mercedes-Benz in 1959. With the help of its in-house accident research department, which was founded in 1969, Mercedes engineers in the following years have developed several groundbreaking innovations in passenger car safety.

The ESF 2009 is the first Experimental Safety Vehicle to be built by Mercedes-Benz since 1974. Like its historic predecessors, this dramatic showcar illustrates trailblazing innovations in the field of safety and makes the progress achieved clearly visible. These amazing but by no means unrealistic ideas include inflatable metallic sections which give more stability to structural components within fractions of a second, as well as the so-called 'Braking Bag'. This airbag housed within the vehicle floor is deployed when a crash is deemed to be unavoidable, and uses a friction coating to support the vehicle against the road surface.

'Safety is a central element of the Mercedes-Benz brand. In this respect we have been setting the pace in the market for almost 70 years. For the benefit of our customers and for motorists in general. The ESF 2009 shows that we still have plenty of ideas and the absolute will, to lead the automobile industry in this field even in future', says Dr. Dieter Zetsche, Chairman of Daimler AG and CEO of Mercedes-Benz Cars.

The ESF 2009 was developed and built completely in the test vehicle workshops in Sindelfingen, Germany. This safety research vehicle based on the Mercedes S400 HYBRID features more than a dozen safety innovations, most of which are fully functioning in demonstration mode. 'With the ESF 2009, we have chosen this particular time to clearly demonstrate the innovative strength of Daimler. Anybody examining the ESF 2009 in detail will recognize that more safety and improved energy efficiency are not necessarily a contradiction in terms. We want
to make progress in both fields with new, trailblazing ideas ', says Dr. Thomas Weber, the member of the Daimler Executive Board responsible for corporate research and development at Mercedes-Benz Cars.

The following five innovations are among the highlights of the ESF 2009:

•PRE-SAFE Structure: The inflatable metal structures save weight or increase the stability of structural components. When at rest, the metal section is in a folded state to save space. If its protective effect is required, a gas generator builds up an internal pressure of 10 to 20 bar within fractions of a second, causing the section to unfold for significantly more stability.
•Braking Bag: This auxiliary brake accommodated in the vehicle floor is a new type of PRE-SAFE® component. If the sensor system concludes that an impact is unavoidable, the Braking Bag is deployed shortly before the crash and stabilizes the car on the road surface by means of a friction coating. The vehicle's vertical acceleration increases the friction, and helps to decelerate the vehicle before the impact occurs.
•Interactive Vehicle Communication: The ESF 2009 is able to communicate directly with other vehicles, or via relay stations. Úsing 'ad hoc' networks and WLAN radio technology, it is e.g. able to receive and transmit warnings of bad weather or obstacles in the road.
•PRE-SAFE Pulse: This further development of PRE-SAFE® is able to reduce the forces acting on the torsos of the occupants during a lateral collision by around one third. It does this by moving them towards the centre of the vehicle by up to 50 millimeters as a precautionary measure. As an active restraint system, it uses the air chambers in the side bolsters of the seat backrests.
•Spotlight lighting function: This partial LED main beam specifically illuminates potential hazards. If the infrared camera of Night View Assist PLÚS e.g. detects deer at the roadside or pedestrians on the road, these can be briefly illuminated beyond the normal area covered by the headlights, as if by a spotlight.
Mercedes-Benz is continuing a longstanding tradition with the ESF 2009: for the ESV Safety Conferences held in 1971 to 1975, the safety experts in Stuttgart built more than 30 experimental vehicles and subjected them to crash tests to satisfy the visionary safety requirements of that time. Four of these ESFs (Experimental Safety Vehicles) were presented to the public, and many of the revolutionary
ideas such as ABS or the airbag first entered series production at Mercedes-Benz.

Daimler management comments on the ESF 2009:

'Safety is one of our core brand values'
'Safety is a central element of the Mercedes-Benz brand. In this respect we have been setting the pace in the market for almost 70 years. For the benefit of our customers and for motorists in general. The ESF 2009 shows that we still have plenty of ideas and the absolute will, to lead the automobile industry in this field even in future.'

Dr. Dieter Zetsche, Chairman of Daimler AG and CEO of Mercedes-Benz Cars.

'Even in economically difficult times, we refuse to make any cuts where innovation is concerned, as shown by the highly complex ESF 2009 project, where we have chosen this particular time to clearly demonstrate the innovative strength of Daimler and Mercedes-Benz. Anybody examining the ESF 2009 in detail will recognize that more safety and less fuel consumption are not necessarily a contradiction in terms. We want to make progress in both fields with new, trailblazing ideas.'

Dr. Thomas Weber, the member of the Daimler Executive Board responsible for corporate research and development at Mercedes-Benz Cars.

'Real Life Safety is about more than scoring points in standardized crash tests, or the number of onboard airbags. The ESF 2009 clearly illustrates the comprehensive approach of Mercedes-Benz with its numerous innovations for more passive and active safety. In line with our claim: One star is sufficient.'

Úlrich Mellinghoff, Head of Mercedes Safety Development

PRE-SAFE Structure: inflatable metal structures


Imagine an inflatable mattress. When it is not needed, it is rolled up flat and e.g. consigned to a shelf in the attic. When inflated, however, it has a highly resistant structure that can easily carry a man weighing over 200 pounds. Inflatable metallic structures work in the same way: when not in use, the metal section is folded together to save space. Once its protective effect is needed, a gas generator just like those used to inflate airbags builds up an internal pressure of 10 to 20 bar within fractions of a second, the metal section is unfolded and the structure has significantly greater stability.

The advantages are obvious, and mainly involve packaging and weight: more stable structures can be accommodated within the increasingly tight installation spaces of an automobile, or weight can be greatly reduced while maintaining the same stability. Úsing the example of the side impact protection member in the doors of the S-Class, the researchers have calculated that around 500 grams less weight per door would be feasible.

Daimler safety researchers examined various applications for these innovative, crash-responsive metal structures, among them side impact protection, the side skirts and the seat cross-members. These have the advantage of being several centimeters away from the impact zone. The gas generator therefore only needs to be activated when a crash has definitely taken place.

One of the still unsolved problems of these protective members is that, unlike the PRE-SAFE® measures already in series production, their active deformation is not reversible. Moreover, the protective members placed along the perimeter of the body shell must be deployed prior to the collision; the pre-crash sensor system must therefore provide highly reliable signals.

Another hurdle is the still uncompetitive cost level of the required gas generators in relation to the cost requirements for weight-saving measures. These crash-responsive metal structures are therefore still a thing of the future - but the same was also once true of standard safety features like the airbag, ABS or ESP®.

Braking Bag: a braking parachute for the car


Airbags in cars have previously only been used as a restraint system for the occupants. In the future they might also be a PRE-CRASH- component, activating an auxiliary brake in the vehicle floor and improving both deceleration and compatibility with the other vehicle involved in the accident.

Energy is not only reducible by braking the road wheels: jet fighters and dragsters use braking parachutes, for example. And as early as 1952, Mercedes-Benz was already experimenting with an air-brake at the Le Mans race: when decelerating, the driver was able to move a metal panel on the roof of his racing SL to a vertical position. Even earlier, coachmen used special wheel chocks. These were placed in front of one of both rear wheels on long downhill gradients, and their iron-clad base helped to brake the vehicle during the descent.

This is an old idea that Mercedes safety researchers have revitalized on a similar principle with the Braking Bag, an airbag installed between the front axle carrier and the underbody paneling. If the sensor system concludes that an impact is inevitable, the PRE-SAFE® system not only initiates automatic emergency braking. At the same time the Braking Bag is deployed just before the crash, supporting the car against the road surface by means of a friction coating. The vehicle's vertical acceleration increases the friction and has an additional braking effect before the impact. The Braking Bag uses the PRE-CRASH sensors in Mercedes-Benz cars, which are already able to initiate preventive occupant protection measures in critical driving situations.

There are several advantages to this unusual auxiliary brake:


•The rate of deceleration is briefly increased to over 65ft/sec/sec. This scrubs additional energy beyond the potentials of a wheel brake, thereby reducing accident severity.
•Because the car is raised upwards by up to three inches within a short time, the dive effect that occurs with conventional brakes is substantially compensated. This improves geometrical compatibility with
the other party in an accident.
•This vertical movement also improves the effects of the restraint systems: the seats move towards the occupants by around one inch, which enables the belt tensioners to take up more slack. The high deceleration rate before the impact has a 'pretensioning' effect on the occupants, so to speak.
•Downward support for the vehicle during the crash reduces the typical diving motion during a collision.
All in all, the braking airbag has the effect of an additional crumple zone. Mercedes engineers have calculated that even at a low 30 mph, the additional deceleration has the same effect as lengthening the front end by 7 inches. Initial driving tests in a C-Class have already shown the effectiveness of this new auxiliary brake - though it will still be some time before the Braking Bag becomes another component of the PRE-SAFE® system.

Interactive Vehicle Communication: cars report what their sensors have detected

A patch of black ice on the next bend? A bank of fog two miles down the road? A new traffic pattern where road repairs are being carried out? What used to come as an unpleasant surprise is far less frightening if the approaching driver receives an up-to-date is warning beforehand. This is a task that will in future be carried out by the other vehicles on the roads at the time - automatically, by radio. This is the basic idea behind Interactive Vehicle Communication.

Cars are nowadays able to collect a great deal of information about the current driving situation, as the numerous sensors, cameras and control units for the dynamic and assistance systems can register e.g. poor weather conditions just as well as sudden braking and avoiding maneuvers, or broken-down vehicles on the road. There are also other sources of information, for example local police reports. This information can be passed on via additional relay stations ('car-to-x') such as radio towers along the roadside, stationary nodal points (e.g. traffic centers and overpasses) or via the internet. The onboard computer classifies all the reports according to plausibility and relevance. Traffic reports on the radio which are out-of-date or irrelevant to the individual driver will then be a thing of the past.

Mercedes engineers have been working on 'Interactive Vehicle Communication' as a technology of the future for more than seven years. The ESF 2009 safety concept vehicle demonstrates the current status of this research: this Mercedes can automatically recognize an approaching police car, for example, and warn its driver by showing a symbol in the display. It is also possible to send and receive warnings of bad weather or obstacles in the road.

The exchange of data between vehicles is via so-called 'ad hoc' networks, connections that are spontaneously formed between the vehicles over short distances. These wireless local area networks (WLANs) are self-organizing, and require no external infrastructure. Transmission and reception is at a frequency of 5.9 gigahertz, over a distance of up to one-third of a mile. In fact the achievable communication range is much greater, as oncoming vehicles pass the messages on.

Cars that communicate with each other can do more than just pass on information: linked to modern proximity control systems such as DISTRONIC Plus from Mercedes-Benz, they can help to harmonize the traffic flow and avoid congestion by automatically selecting the most suitable vehicle speed when joining a motorway. And collisions can be avoided if onboard sensors recognize an impending accident and automatically regulate the distance.

This technology is currently demonstrating its practicality in the 'Safe Intelligent Mobility - Test area Germany' project (simTD), in which Mercedes-Benz and other German manufacturers and suppliers are taking part. Úp to 400 vehicles communicate with each other in these, the world's largest field trials for Interactive Vehicle Communication. simTD is being conducted in the densely populated Frankfurt/Rhine-Main area from autumn 2008 to 2012. Experts expect usable mobile information networks with full coverage to become a possibility when around ten percent of all vehicles have this communications capability.

PRE-SAFE Pulse: an automatic nudge in the ribs

With the multiple award-winning PRE-SAFE® system, Mercedes-Benz has once again been underlining its role as a pioneer in the safety field since 2002: once the system recognizes certain critical driving situations, PRE-SAFE® activates occupant protection measures as a precaution. As a further development, PRE-SAFE Pulse is able to reduce the loads acting on the torsos of the occupants by around one third during a side impact by preventively moving them towards the centre of the vehicle.

Out of harm's way - every millimeter counts during an accident. When an impending lateral collision is recognized, PRE-SAFE Pulse as an active restraint system moves the driver and front passenger towards the centre of the vehicle, using air chambers in the side bolsters of the seat backrests. If the onboard sensors report that a side impact is inevitable, these are inflated within fractions of a second and give the seat occupants a slight nudge in the ribs. This impulse is enough to move them out of the danger zone by up to 2 inches. Even before the accident, it also accelerates the seat occupant in the direction he/she will later take during the accident. This reduces the loads acting on the occupant during the impact. The seat does not need to be replaced or repaired when this preventive safety system has been activated, as PRE-SAFE Pulse is reversible.

PRE-SAFE Pulse is being developed on the basis of the dynamic multicontour seat in the new 2010 Mercedes-Benz E-Class. Depending on the steering angle, lateral acceleration and speed, the inflation pressure and volume of the air chambers in the side bolsters of the seat backrests are already varied to give the driver and front passenger even better lateral support.

Partial high beam: full beam ahead at all times

Whether as brake lights and indicators in many Mercedes models, or as daytime running lights in the new E and S-Class, LED lighting technology is seeing increasing use at Mercedes-Benz. And things will be brightening up at night as well in future: Mercedes lighting specialists are working on an adaptive LED headlight system that automatically excludes oncoming traffic from the cone of light. A special spotlight function also allows potential hazards to receive additional illumination.

High beam, low beam, high beam… anybody traveling on country roads at night is seldom able to drive with the high beams on for very long. The frequency of oncoming traffic dictates that the driver is soon obliged to switch to low beam, either manually or more conveniently using the High Beam Assist in the new Mercedes-Benz E-Class. This is not enough to satisfy the researchers at Mercedes-Benz, however. Because during the phases when the driver switches to low beam - with its shorter range - to avoid dazzling others, it is possible to overlook other road users or potential hazards.

The lighting specialists at Mercedes-Benz are therefore working on an LED-based adaptive high beam system. This enables the driver to leave the high beams switched on constantly. As soon as the system detects oncoming traffic with the help of a camera, it automatically adjusts the light distribution accordingly. The Mercedes ESF 2009 experimental safety vehicle shows precisely how this works. A headlamp is made up of 100 LEDs. These semiconductor elements can be individually activated, so that when there is oncoming traffic, the precise beam area in which other motorists are located can be darkened down. The system recognizes these using an infrared camera. The purely electronic module is also able to respond much faster than present electro-mechanical shutter/roller assemblies.

The light distribution can also be refined in the opposite direction: a special spotlight function in the LED array of the research vehicle also enables potential hazards to be highlighted. If the infrared camera detects pedestrians in the road ahead, for example, they can be briefly lit up beyond the normal high beam illumination, as if by an aimed spotlight. The driver is thus alerted to the potential danger.

Side Reflect: not all Mercedes are grey at night

Reflective material on the body and tires could further improve the lateral visibility of vehicles, and help to avoid accidents at road junctions.

Reflective materials have long been commonplace in children's clothing, and in the case of bicycles it is even mandatory to have reflectors in the wheel spokes. So the engineers at Mercedes-Benz asked themselves why the perceptual safety of cars could not be improved in the same way. Accordingly the ESF 2009 research car features appropriate reflective elements when viewed from the side. These modifications are not visible during the daytime, but the additional benefit shows up when dusk and darkness fall.

Together with the manufacturer Continental, Mercedes specialists have developed a reflective strip on the tires which visually enlarges the wheels in daylight and creates an easily visible band of light when illuminated at night. As a further safety feature there are reflective seals between the doors and the roof, a joint development with the adhesive foil specialist 3M. The aim is to make the vehicle's silhouette more easily visible in the dark. This enables potential accident situations at intersections or in the form of unlit, parked vehicles to be defused.

Reflective foils consist if a reflective base layer with tiny balls of glass. When a ray of light hits the foil, it is refracted by the glass balls, reflected by the base layer and refracted again upon exiting. As a result, most of the light is reflected back in its original direction. Posted on conceptcarz.com.

Belt Bag: a clever combination of a seat belt and airbag

The seat belt is regarded as one of the most important inventions of the 20th Century, and has saved countless lives. It has been further improved with belt tensioners and belt force limiters, but that is not the end of its development: an innovative extension to the width of the belt, known as a Belt Bag, is able to reduce the risk of injury even further in an accident.

When a seat belt limits the movement of its wearer's torso as intended during a collision, it subjects the body to considerable forces. The Belt Bag, on whose development Mercedes-Benz is working intensively with the seat belt specialist Autoliv, practically doubles its width within fractions of a second during an accident. This increase in the width of the belt spreads the pressure over a wider area, thereby reducing the risk of injury. This is particularly beneficial for older passengers, whose ribcage is less flexible.

As the name suggests, the Belt Bag is a combination of a seat belt and airbag. When the crash sensors detect a serious impact, the airbag control unit activates the Belt Bag. A generator at the belt armature inflates the double-layered belt, which has Velcro seams. The volume of the Belt Bag is around 240 cubic in. The developers consider the Belt Bag to deliver the greatest benefits in the rear of the car, where conventional airbags cannot be installed. It is therefore conceivable that the Belt Bag could be used here by Mercedes-Benz in the foreseeable future.

Child Protect System: safety and comfort for very small passengers

Mercedes engineers have thought about how children might travel even more safely in a car.

The two major advantages of the Mercedes concept study 'Child Protect System' over conventional child safety seats are an improved protective effect and greater comfort for the child. This is accompanied by a high level of quality and attractive visual integration of the seat into the interior of Mercedes models. This system jointly designed with the restraint system specialist Takata is suitable for children aged between three and 12 years (weight categories II and III). One special feature is its modular construction, as the height and width can be individually adapted to the child's physical proportions.

'Child Protect System' has a tubular frame construction. This design offers better support and greater rigidity than versions of molded plastic during a side impact. The prominent side bolsters in the shoulder and head area keep the child in place and minimize body movement during an accident. At the same time they prevent the child from coming into contact with vehicle components penetrating into the interior, or with the passenger in the adjacent seat. This seat study, which is approved according to the ECE R44.04 standard, is also equipped with automatic, sensor-controlled airbag deactivation on the front passenger seat.

As an additional benefit, Mercedes engineers are considering the addition of a carriage subframe to the child seat. This would also ensure that children travel in comfort, style and safety outside the car.

PRE-SAFE 360°: full emergency braking before an impact

With the multiple award-winning PRE-SAFE® system, Mercedes-Benz has once again been underlining its role as a pioneer in the safety field since 2002: once the system recognizes certain critical driving situations, PRE-SAFE® activates occupant protection measures as a precaution. As a further development, PRE-SAFE 360° monitors not only the areas to the side, but also to the rear of the vehicle.

PRE-SAFE 360° uses short-range or multi-mode sensors to monitor the area behind the vehicle to a range of up to 200 feet. If the accident early-warning system registers that a collision is unavoidable, the brakes are applied around 600 milliseconds before the impact. If the already stationary car is braked during a rear-end collision, this not only prevents secondary accidents where the car is e.g. uncontrollably pushed into an intersection or onto a pedestrian crossing. The severity of possible whiplash injuries to the occupants can also be reduced by application of the brakes, as the vehicle and therefore its occupants have less forward acceleration. The driver always has the final decision with PRE-SAFE 360°, however: if he accelerates because he is able to prevent the rear-end collision by moving forward, for example, the brakes are instantly released.

Contrary to the widely held opinion among drivers, it does not make sense to take one's foot off the brake pedal before an impending rear-end collision. The correct action would be to apply the brakes as hard as possible, however accident research findings show that the driver of a stationary vehicle impacted from the rear is moved backwards by up to 8 inches. This inevitably causes his feet to slip from the pedals.

The protective effect of PRE-SAFE 360° supports that of the NECK-PRO crash-responsive head restraints, which are already standard equipment in many Mercedes model series. 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 1.5 inches and upwards by 1 inch within a matter of milliseconds. This means that the heads of the driver and front passenger are supported at an early stage than with conventional head restraints.

Size Adaptive Airbags: tailor-made airbags

The 1980 Mercedes S-Class (W 126) was the first series production car equipped with an airbag. In the meantime airbags have firmly established themselves across all vehicle segments. Airbags have saved many human lives and reduced the severity of injuries. Mercedes safety specialists are now working on a further improvement to their protective effect by developing airbags with a variable volume.

There are already adaptive airbags at Mercedes-Benz today, for in many model series the airbags are activated in two stages depending on the assessed severity of the impact. Future generations of this restraint system will not only take accident severity into account, but adapt themselves to the individual vehicle occupants: 'Size Adaptive Airbags' automatically adjust their volume to the seating position and stature of the front passenger as recognized by the sensors. For whether a small front passenger is hunched-up close to the dashboard or a tall front passenger has his seat moved well back is certainly a factor in the protective effect of the airbag. The weight of the front passenger, and therefore the forces acting on the airbag during an accident, are also important.

'Size Adaptive Airbags' enable occupant contact with the airbag to be optimally timed, whatever his weight and seating position. The restraint system can therefore dampen the impact to optimum effect. This Mercedes development varies the volume on the front passenger side between 3 and 5 cubic ft. For purposes of comparison, conventional front passenger airbags have a volume of around 4 cubic ft.

The system uses three retaining bands with which the airbag contours are adjusted to limit the volume. The retaining bands are fitted on electrically driven spools. When the airbag is activated, only as much band length is released as the control unit has calculated on the basis of sensor data for the seating position and weight of the occupant.

Rear seat camera: keeping an eye on the kids

With the help of a small camera, drivers will in future be able to keep children traveling in the rear under control without taking their eyes off the road.

'Mom, Vanessa keeps pulling my hair!' 'John's seat belt isn't buckled.' - Parents know that when the kids are on board, there is usually no shortage of action in the rear seats. But if the driver looks back to see what is going on, there is a risk of an accident. Accordingly Mercedes safety experts have developed 'Rear seat camera', a simple camera system that enables the kids to be observed without taking one's eyes off the road.

A small camera is mounted on the roof lining behind the front seats. If required its images can be transferred to the dashboard display - not in video form, but as sequences of stills to avoid distraction. The camera position provides a slight bird's-eye view, which allows children in rear-facing child seats to be observed more easily.

'Rear seat camera' also shows rear areas that are not easy for the driver to observe, e.g. the seat directly behind. And in the case of an estate car, SÚV or van, it is also possible to monitor the luggage compartment. This is very useful if pets are on board, for example.

Interseat Protection: don't get too close to me

Danger not only comes from the outside during an accident. In unfortunate cases even passengers wearing their seat belts can come into contact and injure each other. Interseat Protection in both seat rows helps to prevent this.

Mercedes safety specialists are presenting two proposed solutions in one with Interseat Protection: a protective system for the driver/front passenger and one for the rear-seat passengers. As a common feature of both, the occupants are physically separated from each other if the PRE-SAFE® system registers an accident. Within fractions of a second, a lattice-like airbag support structure extends from between the front seats to keep the driver and front passenger apart. A seat-mounted solution like this has the advantage that the protective barrier adapts itself to the position of the front seats.

The seat position does not need to be taken into account in the rear, therefore a protective pad located above the centre armrest is used when an accident is detected. This pad helps to prevent the two passengers in the rear from striking each other. When the pad is at rest it can be activated as part of PRE-SAFE®. Within fractions of a second, the seat divider emerges and the two head supports are deployed.

Mercedes accident research has shown that during a side impact, and also during a rollover, the heads of the passengers move along different paths: around 50 milliseconds after the accident, the head of the person facing the impact changes the direction of its evasive movement towards the center of the vehicle - impelled by the sidebag and head airbag. A second important finding from these analyses is that a collision between the passengers can only be avoided if the torso is supported. The protective pad of the Interseat Protection system is dimensioned accordingly.

In normal cases the protective pad in the rear is more of an innovative comfort feature: the pad is designed to be extended by the passengers at the touch of a button, when it can be used as a head and shoulder support for a comfortable sleeping position. It would also be conceivable to use the space for storage, a refrigerated compartment, or an entertainment console.

Hybrid Battery Shield: seven-stage safety system

A drive train with hybrid technology lowers fuel consumption and CO2 emissions. At the same time this introduces high-voltage electricity and sophisticated battery systems into passenger car engineering, however. Thanks to their long experience with fuel cell technology, Mercedes development engineers are extremely well prepared for the new challenges this presents. The result is a comprehensive, seven-stage safety concept.

The challenge lay not only in complying with all the worldwide and in-house crash test requirements, but also in ensuring the greatest possible safety for the electrical components. This safety system already applies in production, includes workshop personnel during servicing and maintenance, and also takes the emergency services into account when passengers need to be recovered following an accident. The seven-stage concept in detail:

1. In the first stage all the wiring is color-coded to eliminate confusion, and all components are marked with safety instructions. This makes the regular technical inspections easier to carry out.

2. The second stage comprises comprehensive contact protection for the entire system by means of generous insulation and newly developed, dedicated connectors.

3. As part of the third stage, the lithium-ion battery has been developed with numerous carefully coordinated safety measures. This innovative battery is accommodated in a high-strength steel housing, and also secured in place. Bedding the battery cells in a special gel effectively dampens any jolts and knocks. There is also a blow-off vent with a rupture disc and a separate cooling circuit. An internal electronic controller continuously monitors the safety parameters and immediately signals any malfunctions.

4. The fourth stage of the safety concept includes separation of the battery terminals, individual safety-wiring for all high-voltage components and continuous monitoring by multiple interlock switches. This means that all high-voltage components are connected by an electric loop. In the event of a malfunction the high-voltage system is automatically switched off.

5. Active discharging of the high-voltage system as soon as the ignition is switched to 'Off', or in the event of a malfunction, is part of the fifth stage.

6. During an accident, the high-voltage system is completely switched off within fractions of a second.

7. As the seventh and last stage, the system is continuously monitored for short circuits.

'Still many more ideas for more safety'

Interview with Prof. Dr. Ing. Rodolfo Schöneburg, Head of Safety Development, Mercedes-Benz Cars.

Prof. Dr. Ing. Rodolfo Schöneburg was born on 30 October 1959, studied aerospace engineering and obtained his doctorate at the Technical Úniversity of Berlin. He holds an honorary professorship at the College of Technology and Business Economics (HTW) in Dresden. He has been active as the head of the center for safety/vehicle functions at Mercedes-Benz since April 1999. It was under his leadership that the preventive occupant protection system PRE-SAFE® entered series production in 2002, with which Mercedes-Benz started a new era in vehicle safety. Here are some of Prof. Schöneburg's comments on the ESF 2009experimental safety vehicle.

Question: Prof. Schöneburg, during the period from 1971 to 1974 Mercedes-Benz presented four Experimental Safety Vehicles (ESFs) to the public. Then there was silence. Why?

Prof. Schöneburg: At the end of the 60s, vehicle safety suddenly became a focus of public attention. In 1969 the Mercedes-Benz Safety Center was founded in
Sindelfingen. Numerous developments were initiated, ranging from active safety with ABS and ESP® to fundamental improvements in vehicle structures and innovative restraint systems such as the airbag. All of these were tested and presented in our ESFs, and from the mid-70s more and more of these innovations reached series production maturity. Accordingly they were subsequently presented with the launch of new series production models.

Question: So why are you presenting another research vehicle now, the ESF 2009?

Prof. Schöneburg: Both in-house and externally, the large number of safety features that we already have in our series production cars has created the impression that we do not have much more to offer in this respect. This impression is quite wrong - we have a wealth of ideas on how safety might be improved still further. Some of these can be realized within a relatively short time, for example PRE-SAFE® for rear-end collisions. Other concepts like the inflatable metal sections in PRE-SAFE Structure lie well in the future. And with Interactive Vehicle Communication we are only just starting to develop a completely new field. The ESF 2009 comprehensively offers up all these perspectives. Moreover, our intention was to send out certain signals for the ESV Conference, which is being held in Stuttgart for the first time since 1971.

Question: What is particularly special about the ESF 2009?

Prof. Schöneburg: As with the ESFs of the 1970s, this is a comprehensive embodiment of our safety philosophy. The primary aim is to prevent accidents in the first place. Where this is not possible, the aim is to mitigate their effects. Moreover, we want to approach both of these goals without increasing the vehicle's weight, restricting its practicality or compromising the autonomy of the driver. He or she bears the final responsibility - and the car should provide support in the process.

Question: What new ideas have been incorporated into the ESF 2009 to prevent accidents where possible?

Prof. Schöneburg: These start with the concept of 'seeing and being seen'. The LED headlamps of the ESF 2009 not only illuminate the road further and more efficiently, but also ensure that other detected road users are not dazzled in the process. The Spotlight function is something quite new: it precisely pinpoints obstacles or objects that have been recognized by the infrared Nightvision camera. Thanks to new reflective strips on the sides, which leave the body design unaffected during daytime, the ESF 2009 is also much more easily visible to other road users in the dark. One technology which we think has tremendous potential for the next few years and decades is car-to-car communication. This makes it possible to warn drivers of hazards on their route as the situation requires.

Question: In addition to highly developed restraint systems, Mercedes cars with PRE-SAFE® have a preventive safety system that can recognize an impending accident and mitigate its effects with numerous actions right up to automatic emergency braking. Is it still possible to make significant improvements to this already high standard?

Prof. Schöneburg: Yes indeed. The basis for PRE-SAFE® is a network of onboard sensors and systems, and this is where we still have plenty of ideas for fur ther developments. Take side impacts as an example: with the help of air chambers in the seats, it would be possible to move the passengers away from the danger zone to some extent. We have already spoken about improvements where rear-end collisions are concerned. And the Braking Bag is a completely new approach to dissipating energy before an impact occurs.

Question: At first glance this is a crazy idea - using an airbag under the car to force a high-friction coating against the road surface as an auxiliary brake…

Prof. Schöneburg: …certainly unusual, but by no means crazy. Initial trials of the principle have shown this idea to have considerable potential. In the next few years we intend to research and develop this potential further.

We look forward to the results, and thank you for this interview.

The history of Mercedes-Benz Experimental Safety Vehicles (ESFs): milestones in safety development

In the early 1970s, the pioneers of the ESV program at Mercedes-Benz built over 30 experimental vehicles for research on future automotive safety systems. These prepared the ground for numerous innovations, some of which only reached series production maturity years later. They include ABS, belt tensioners and belt force limiters, airbag and side impact protection.

In the 1960s it became impossible to ignore a negative aspect of mass motorization: more and more people were being killed on the roads. In 1968 the ÚS Department of Transport therefore started a program for the development of Experimental Safety Vehicles (ESVs), and initiated the international 'Technical Conference on the Enhanced Safety of Vehicles'. In 1970 the first requirements to be met by ESVs were defined. These included an extremely demanding frontal and rear-end impact against a rigid barrier at 50 mph, and a side impact against a mast at 12 mph. The test vehicles also had to withstand minor accidents at 10 mph without lasting deformations at the front and rear. It was also believed that American consumers would not accept having to actively put on and fasten a seat belt, therefore automatic belt systems were theorized which would envelop the front occupants when the doors were closed.

The American government also issued an invitation to foreign countries to take part in this safety research. In 1970 this gave rise to the still active European Enhanced Vehicle Safety Committee (EEVC).

At Mercedes-Benz the challenge of designing vehicles with even more safety was taken up with great enthusiasm. After all, the company was already able to look back on more than 20 years of continual safety research at the time. And about ten years previously, in 1959, the fundamental basis for all future safety developments had already entered series production at Daimler-Benz: the safety bodyshell with impact energy absorbing crumple zones at the front and rear, and a rigid passenger compartment between them.

From spring 1971 the ESV project went full-steam ahead in the separate safety research department founded at Mercedes-Benz in Sindelfingen in 1969. All in all, 35 vehicles were built and tested over the four following years. The first test took place on 12 March 1971 with a W 114 from series production, i.e. the middle of the range at the time. The car was subjected to a frontal impact on a rigid wall at 50 mph. The tests also included frontal and rear-end collisions, lateral collisions with masts and other vehicles, and also drop tests from a height of 2 feet.

The development focus was not only on occupant protection during an accident by means of correspondingly improved vehicle structures and innovative restraint systems, however. Even almost forty years ago, the still valid, comprehensive approach to safety always taken by Mercedes-Benz applied, as an extract from the description of the ESF 13 first presented in May 1972 shows.

This already refers to still current concepts such as driver-fitness safety through seating comfort, climate control and non-intrusive vibration/noise characteristics. Where perceptual safety is concerned, the ESF 13 featured pneumatic beam range control, a headlamp wash/wipe system, a tail light monitoring system in the cockpit, a rear wiper and a safety paint finish with a light color and contrasting strips. External safety features for the protection of pedestrians and two-wheeled travelers included foam-covered front and rear bumpers, rubber drainage channels and rounded door handles. Fire safety was also taken into account: the fuel tank was above the rear axle, well away from the exhaust system. The fuel pump was, if necessary, deactivated by a mechanism that depended on the engine oil pressure, a valve system prevented any spillage of fuel if the car stood at an unusual angle, the materials used in the interior were fire-retardant and a fire extinguisher was conveniently mounted on the lower front of the driver's seat.

Mercedes-Benz presented the following four ESFs to the public:

ESF 5: developed on the basis of the W 114 ('Strich Acht') series and presented at the 2nd International ESV Conference from 26 to 29 October 1971 in Sindelfingen

•Designed for an impact speed of 50 mph
•Five three-point seat belts, each with three force limiters, front seat belts self-fitting.
•Driver and front passenger airbag, also an airbag in each of the front seat backrests for rear passengers on the outer seats. This increased the weight of the front seats to 139 lbs each (standard: 35 lbs).
•Extensive structural modifications in the front end and sides
•Curb weight: 4,543 lbs (1,466 lbs more than standard)
•Overall length: 210 inches (25 in. more than standard)
•Wheelbase increased by 4 inches, so as to maintain spaciousness in the rear despite the larger seats
•Front-end extension incl. hydraulic impact absorber: 14.5 inches
•Experimental V6 engine to gain deformation space at the front
•Dashboard with impact-absorbing metal structure on the front passenger side
•All relevant impact areas in the interior were padded with polyurethane foam, especially the doors, pillars and roof frame
•Doors without quarterlights, power windows
•Headlamp wipers, beam range control, parallel rear window wipers
•Side marker lights, tail lights with standstill relay and control function
•Windscreen and rear window of laminated glass, bonded in place
•Pedals with rounded-off lower section
•ABS brakes
ESF 13: Stylistically revised variant of the ESF 5, presented at the 3rd International ESV Conference from 30 May to 2 June1972 in Washington (ÚSA)

•Restraint systems and other features adopted from the ESF 5
•Curb weight: 4,631 lbs (1,555 lbs more than standard)
•Overall length: 206 inches (21 inches more than standard)
•Front-end extension incl. hydraulic impact absorber: 16.5 in
•The changes to the external dimensions were primarily the result of the redesigned front and rear ends. The bumpers were now designed to be underrun, while the deformation path remained the same. The front and rear were extended to reduce the bumper overhang to an acceptable level.
ESF 22: Based on the W 116 series (1971 S-Class) and presented at the 4th International ESV Conference from 13 to 16 March 1973 in Kyoto (Japan)

•Designed for an impact speed of 40 mph
•Four three-point belts, each with three force limiters and a belt tensioner
•Driver: airbag instead of belt tensioner
•Curb weight: 4,466 lbs (633 lbs more than standard)
•Overall length: 206 in. (11 in more than standard)
•Front-end extension incl. hydraulic impact absorber: 9.6 in.
•ABS brakes
ESF 24: Modified S-Class (W 116) presented at the 5th International ESV Conference from 4 to 7 June 1974 in London (Great Britain)

•Restraint systems identical to ESF 22
•Curb weight: 4,256 lbs (423 lbs more than standard)
•Overall length: 205 in (10.5 in. more than standard)
•Front-end extension incl. hydraulic impact absorber: 6 in.
•ABS brakes
This laid the foundation for the level of safety found today in cars bearing the Mercedes star. Extract from the summary test report (1975): 'The ESF 24 can be regarded as the completion of the project, as this vehicle represents the best possible compromise between the original ESV requirements and our current series production cars.'

At Mercedes-Benz, safety was already included in the development specifications for new cars decades before the ESV program, and in rapid succession the ideas first realized as part of the ESF project entered series production as well.

The milestones included:
1978: premiere of the ABS as an option in the S-Class
1981: driver airbag and belt tensioner available in the S-Class
1995: belt force limiters and sidebags enter series production of the E-Class

This is how the ESF 2009 was created: 13 innovations, 1 team

The ESF 2009 is the first Experimental Safety Vehicle Mercedes-Benz has built since 1974. Like its historic predecessors, it attractively combines trailblazing innovations in the field of safety and makes the progress achieved visible. Integrating all the ideas and implementing them for a clear demonstration was an extraordinary challenge for the team in the test vehicle workshops.

The approval for the ESF was given in October 2008, and the decision was received with great enthusiasm in the test workshop: 'Making safety visible - I was quickly able to assemble a highly qualified team for this interesting project', says Axel Wittig, the team leader for the entire workshop facility. 'The complexity of this assignment was a welcome challenge, as we not only had to integrate the numerous innovations into an S400 HYBRID, but also make them fully functioning in demonstration mode and provide a look behind the technical scenes by incorporating eight inspection windows in the hood, bumpers and doors.'

The core workshop team for the ESF 2009, headed by coordinator and facilitator Hans Peter Hiller, consisted of three model-builders and two electricians. The team was supported by Jürgen Arnold, who took care of the electrical engineering, and designer Matthias Rissmann, who e.g. prepared the body openings for the inspection windows. It was only possible to keep to the ambitious time-plan because countless internal (from the upholstery specialists in Design to production engineering) and external suppliers gave rapid assistance. 'The great enthusiasm for the core Mercedes expertise of safety could be felt at all times', project manager Michael Fehring remembers: 'The 'Daimler spirit' ensured rapid decisions without time-consuming consultation processes.' Sheer fascination for technology also played an important part. The chance to take a look into a radar sensor, which is normally only supplied as a 'black box' but was in this case integrated into the front bumper in a cutaway state, attracted many an engineer - even those not involved in the ESF 2009 project.

The complexity of this project, which involved the integration of 13 safety innovations into the hybrid version of the S-Class that only existed as a prototype when the work started, is already shown by the fact that a completely new wiring harness had to be designed and produced. At the heart of the demonstration technology is a divided compressed air tank in the trunk, with a compressor and external power supply, which provides air for the airbags and the air chambers for PRE-SAFE Pulse and Interseat Protection. The finishing touch for the ESF 2009 is a central remote control system for all the functioning demonstrations.

The result of all this work was two experimental vehicles in the special ESF paint finish, which includes black-painted chrome trim and reflective strips on the door seals and tires: the actual ESF 2009 and its externally identical brother, which can be used for driving and photographic purposes.

Today, tomorrow and the day after: all the safety innovations at a glance:

Cornering lights: this function of the bi-xenon headlamps and the Intelligent Light System provides more safety at intersections and when driving slowly on tight bends.

ADAPTIVE BRAKE: this Mercedes brake system offers assistance functions, such as a HOLD function and Hill Start Assist, for even greater safety and comfort.

Adaptive front airbags: the front airbags deploy in two stages, depending on accident severity.

Adaptive High Beam Assist: this system adjusts the range of the headlamps in accordance with the distance to oncoming vehicles/vehicles traveling ahead.

Adaptive brake lights: flashing brake lights warn vehicles behind in an emergency braking situation.

Active Light System: the Intelligent Light System's bi-xenon headlamps follow the driver's steering movements.

Active Hood: in the event of an accident, the rear of the hood is raised by 2 inches in order to reduce the risk of injury to pedestrians.

ATTENTION ASSIST: this Mercedes system detects driver drowsiness and gives a warning.

Motorway mode: from 55 mph the entire width of the highway is illuminated, improving the driver's range of vision by around 164 feet.

Belt Bag: this widened section of the seat belt is activated by the airbag control unit when the crash sensors detect a serious impact. A generator at the belt armature inflates the double-layered belt, which has Velcro seams. The increase in belt width distributes the forces over a wider area, thereby reducing the risk of injury.

Bi-xenon headlamps: gas-discharge lamps for low and main beam improve safety at night.

Braking Bag: This auxiliary brake accommodated in the vehicle floor is a new type of PRE-SAFE® component. If the sensor system concludes that an impact is unavoidable, the Braking Bag is deployed shortly before the crash and stabilizes the car on the road surface by means of a friction coating. The vehicle's vertical acceleration increases the friction, and helps to decelerate the vehicle before the impact occurs.

Brake Assist PLÚS: this system uses radar sensors to recognize an impending rear-end collision, calculates the necessary degree of braking assistance and makes it available immediately when the driver presses the brake pedal.

Rear seat camera: a small camera in the roof lining helps drivers to keep an eye on children travelling in the rear.

Child Protect System: innovative child safety seat system with a metal frame and padded elements. It improves protection during a side impact, and is also considerably more comfortable.

DISTRONIC PLÚS: this radar-based proximity control system automatically keeps the car at a set distance from the vehicle in front, braking it to a standstill if necessary and accelerating when the gap ahead is sufficiently large. If the distance to the vehicle ahead decreases too quickly, the system gives the driver visual and audible warnings.

Enhanced foglamps: This function of the Intelligent Light System pivots the headlamp outwards to illuminate the road more effectively.

Headlamp Assist: a sensor on the windscreen automatically switches the headlamps on when darkness falls.

Adaptive High Beam Assist: a camera on the inside of the windscreen recognizes oncoming traffic and automatically dips the headlamps - then switches back to high beam.

Speed Limit Assist: a camera fitted behind the windscreen detects speed limit signs at the roadside. The relevant limit is then displayed in the instrument cluster.

Belt force limiters: this technology reduces the force exerted by the belt strap on the seat occupant during a crash.

Belt tensioners: any slack in the seat belt strap is instantly taken up during a crash to reduce the forward movement of the occupants caused by the impact.

Hybrid Battery Shield: extensive protective measures for the lithium-ion battery of the S400 HYBRID, which are integrated into the seven-stage safety concept. This innovative battery is accommodated in a high-strength steel housing, and also secured in place. Packing the battery cells in a special gel effectively dampens any jolts and knocks. There is also a blow-off vent with a rupture disc and a separate cooling circuit. An internal electronic controller continuously monitors the safety requirements and immediately signals any malfunctions.

Intelligent Light System: This innovative headlamp technology provides five lighting functions which are activated depending on the driving and weather conditions (also see Cornering lights, Country mode, Motorway mode, Active Light System and Enhanced foglamps).

Interactive Vehicle Communication: cars are able to communicate directly with each other, or via relay stations. Úsing 'ad hoc' networks and WLAN radio technology, they are e.g. able to receive and transmit warnings of bad weather or obstacles in the road.

Interseat Protection: these protective systems for the first and second seat rows physically separate the occupants if the PRE-SAFE® system registers an accident. During an impact, they therefore help to ensure that the passengers do not come into contact and injure each other.

Child seat recognition: A transponder system automatically recognizes whether a rear-facing child seat is installed, and deactivates the front passenger airbag if this is the case.

Kneebag: in the event of a crash, an additional airbag reduces the forward movement of the driver caused by the impact.

Night View Assist PLÚS: the display in the dashboard shows a realistic grey-scale image from an infrared camera that monitors the road ahead of the vehicle. Any pedestrians detected are additionally highlighted in the display.

Country mode: this function of the Intelligent Light System replaces the previous low-beam headlamps and provides broader and brighter illumination of the opposite road lane.

LED-Array: groups of LED elements that replace conventional headlamps. The individual LEDs (Light Emitting Diodes) can be controlled separately (see Partial High Beam and Spotlight)

NECK-PRO head restraints: crash-responsive head restraints support the heads of the driver and front passenger at an early stage during a rear-end collision, reducing the risk of a whiplash injury.

Partial High Beam: this enables the driver to leave the high beams constantly switched on. Once the system recognizes oncoming traffic with the help of a camera, it automatically adjusts the light distribution accordingly.

PRE-SAFE®: anticipatory safety measures are taken to protect the occupants if an accident risk is detected.

PRE-SAFE® Brake: if there is imminent danger of a rear-end collision, this system brakes the vehicle automatically if the driver fails to react.

PRE-SAFE 360°: when the system recognizes an impending rear-end collision, the stationary vehicle is automatically braked. This helps to prevent secondary accidents and mitigate the severity of possible whiplash injuries.

PRE-SAFE Pulse: This further development of PRE-SAFE® is able to reduce the forces acting on the torsos of the occupants during a lateral collision by around one third. It does this by moving them towards the centre of the vehicle by up to 2 inches as a precautionary measure. As an active restraint system, it uses the air chambers in the side bolsters of the seat backrests.

PRE-SAFE Structure: The inflatable metal structures save weight or increase the stability of structural components. When at rest, the metal section is in a folded state to save space. If its protective effect is required, a gas generator builds up an internal pressure of 10 to 20 bar within fractions of a second, causing the section to unfold for significantly more stability.

Real Life Safety: Mercedes philosophy for comprehensive safety. This takes the findings from accident research into account, and integrates all the active and passive safety systems.

Reversing camera: as soon as reverse gear is selected, the dashboard display shows the image from a camera covering the area immediately to the rear of the vehicle.

Sidebags: these airbags reduce the risk of injury in a collision from the side.

Side Reflect: special reflective strips inset into the door seals and tires. These are invisible during the daytime, but make the vehicle's silhouette more easily visible at night.

Size Adaptive Airbags: these airbags automatically adjust their volume according to the seating position and stature of the front passenger which have been recognized by sensors. The system uses three retaining straps to adjust the airbag contour, and therefore limit the volume.

Spotlight lighting function: This partial LED high beam specifically illuminates potential hazards. If the infrared camera of Night View Assist PLÚS e.g. detects deer at the roadside or pedestrians in the road, these can be briefly illuminated beyond the normal area covered by the high beams, as if by a spotlight.

Lane Keeping Assist: a camera behind the windscreen recognizes clear highway markings and gives a warning if the car unintentionally leaves its lane.

Blind Spot Assist: this radar-based system warns the driver before a lane-change if it
detects another vehicle in the vehicle's blind spot.

Windowbags: like a curtain, these large airbags extend from the A to the C-pillar in a side impact.

Source - Mercedes-Benz