Mercedes-Benz F 700

Since the beginning of the 1980s Mercedes-Benz has introduced twelve research cars. This series of exciting and pioneering automobiles – from Auto 2000 in 1981 to the latest F 700 – documents the resolution and foresight with which the Mercedes-Benz engineers delve into central topics of research and technology and develop innovative solutions for the future.

Many systems in research cars that were considered revolutionary years ago are in use in Mercedes-Benz production cars today. They include, for example, the DISTRONIC proximity control – it was shown in 1991 in the F 100 and then appeared in the 1998 S-Class. The Active Body Control suspension system employed today in the CL, S and SL-Class is an example of successful technology transfer from research to production car, as are the windowbag and the active light function. The F 500 Mind provided the inspiration for further hybrid development. It combined the V8 diesel engine of an S-Class with an electric motor. At the time this duo was the most powerful, torquiest hybrid drive for a rear-wheel drive passenger car.

The F 700 will continue down this path and show the way to series production for significant innovations in drive and comfort technology. In the words of Professor Dr. Herbert Kohler, responsible for Group Research & Advanced Engineering Vehicle and Powertrain at DaimlerChrysler AG, “the F 700 shows what the big touring sedan of the future will look like. It offers environmentally compatible mobility combined with utmost comfort and an effortlessly superior drive.”

With that, the F 700 meets the growing demands on luxury-class automobiles. The focus is on conserving resources and protecting the environment: low consumption, low CO2 emissions, low pollution levels. For in future there will continue to be considerable demand for the comfortable mobility provided by large sedans.

Making this kind of mobility sustainable is a major responsibility which Mercedes-Benz faces up to in an all-out way. The F 700 is an unmistakable sign of this: as a research car, it demonstrates with innovative approaches and technologies not only how resources can be conserved and the environment protected, but also how driver and passengers can be relieved of stress and can travel completely at ease.

The F 700 research car shows new ways to achieve resource-conserving mobility. The heart of the car is the novel drive system which combines the advantages of the low-emission spark-ignition engine with the consumption advantages of the diesel drive. The diesel engine’s crucial advances to its current combination of dynamic performance and low fuel consumption were made possible by turbocharging and common-rail direct injection – both pioneering achievements of Mercedes-Benz.

DIESOTTO engine

The “DIESOTTO” drive takes this some decisive steps further: consistent downsizing through reduction of displacement and the number of cylinders makes for improved efficiency, and a hybrid module assists the internal combustion engine mainly in stop-and-go operation. Moreover, the diesel principle with controlled auto ignition (CAI) makes its debut in the spark-ignition engine.

On starting and at full load, the air-fuel mixture is not ignited by a sparkplug as in a conventional petrol engine. The controlled auto ignition (homogeneous combustion) to which the DIESOTTO automatically reverts within its working cycle occurs under partial load conditions, i.e. at low and medium engine speeds. As a result of homogeneous combustion at reduced reaction temperatures, very low emissions of nitrogen oxides are produced. The rest of the emission control work in the DIESOTTO drive is handled by a standard 3-way catalytic converter. In addition, in order to combine the individual subsystems into one drive concept, a highly efficient engine management and control system has been implemented.

The drive unit of the F 700 is a compact 4-cylinder with a displacement of 1.8 litres, and yet it ensures that feeling of effortless, superior power afforded by a luxury sedan: a 2-stage turbocharger system ensures good response and torquey pulling power. In addition, when the car moves off the internal combustion engine is assisted by the electric motor of the hybrid module. The maximum output is 175 kW (238 bhp), the electric motor pitches in another 15 kW (20 bhp), and the system’s maximum torque is about 400 Nm. The 0 to 100 km/h sprint time of 7.5 seconds attests to the dynamics of the F 700, whose top speed is limited to 200 km/h.

Despite these impressive performance figures, the consumption of the F 700 in the standard cycle is only about 5.3 litres, equivalent to CO2 emissions of 127 gms/km – extremely low for an automobile of this category.

Similar advances are made by the F 700 in the area of ride comfort. Mercedes-Benz has always been a leader in the area of road roar/tire vibration characteristics and suspension comfort: the Active Body Control suspension system in the CL, S and SL-Class sets the standard worldwide with its unrivaled combination of comfort, handling safety and dynamics. This system is now surpassed by the new technology of the F 700.

For here, once again, the new research car takes an important step to the future: thanks to its active PRE-SCAN suspension, the vehicle not only responds with great sensitivity to roadway unevenness; more than that, it acts with foresight. PRE-SCAN uses two laser sensors in the front headlamp units as “eyes”. They deliver a precise image of the condition of the roadway. Based on the image supplied by the laser sensors and the information on the vehicle state, the control unit figures out a specific strategy which the high-pressure hydraulics translate into precisely calculated fluid flows and pressures for each single wheel.

The exceptional efficiency of the overall concept of the F 700 is evident at first sight: its design is distinguished by soft, flowing forms. “Aqua Dynamic” is the name the designers have given to this design idiom with which they translated the flow dynamics of a fish into the design of an exceptional automobile. Besides, the design provides an immediately indication that much room has been given to the passengers.

With an overall exterior length of 5.18 metres, the F 700 is a little shorter than the current long-wheelbase version of the S-Class, but with its generously sized wheelbase of 3.45 metres the research car excels the production model by impressive 28.5 cm.

The side view of the F 700 is marked by the tense curves of the roof contour and shoulder line. This sedan puts a new interpretation on a design theme of Mercedes-Benz, for the current CLS also displays such tense lateral lines. The distinctively shaped front wheel arches likewise are inspired by a current model – the S-Class. After all, even a research car is always a Mercedes-Benz and stands on the foundation of the automobile brand with the richest tradition in the world.

The headlamps of the F 700 are a futuristic interpretation of the Mercedes-typical twin-headlamp face. Two vertical rows of linear LED arrays with superposed lens have the function of driving lights. A third vertical row of single high-performance LEDs are the daytime driving lights. Together with the continuous contour lights they give the F 700 an unmistakable appearance even by night. The “eyes” of the F 700 are integrated into the headlamps: these laser scanners gather the roadway data for the active PRE-SCAN suspension. Unlike any conventional automobile this sedan “sees” the surface profile of the road ahead of it.

The driver’s door also “observes” its surroundings attentively. In the base of the mirror of this PRE-SCAN door there is a very compact laser scanner which examines the area in which the door swings open for any obstacles. If collisions threaten, the door is arrested by a controllable hydraulic cylinder.

Rear seat can be reversed to face backwards

The extremely spacious and flexible interior concept is manifested outwardly not only by the long wheelbase. Two large glazed areas in the roof also emphasize the spacious design. Owing to the use of natural materials like leather and cork and to a harmonious brown and beige color scheme, the interior makes an elegant and light impression and appears very up-scale. The right rear door of the F 700 is hinged at the rear. Reversing the direction in which the door opens makes it easier to get into the REVERSE seat – another innovation in the new Mercedes-Benz research car. The REVERSE seat is the heart of the new seating concept, a completely new design thought out for the right rear seat. It breaks up the firmly established seating arrangement of a sedan and instead permits individual seat and rest positions, both facing the direction of travel and in the opposite direction.

This provides the opportunity for very different kinds of use depending on the purpose and duration of travel. Four persons sit in the conventional way facing the direction of travel. If the front passenger seat is unoccupied, at the push of a button the right rear seat can be moved to a relax position. To do this one moves the front passenger seat forward and folds the backrest towards the dashboard. Another use is made possible by the special functionality of the REVERSE seat (right rear seat). A new type of mechanism allows the passenger to sit in reverse direction and look out the back. He can chat face to face with his neighbor, work, rest, or enjoy the audiovisual entertainment. A monitor with an overall diagonal display measurement of 51 cm and a surround sound system create a cinema atmosphere. More than anything else though, the monitor delivers fascinatingly deep images with its 3D technology.

The innovative operating concept conduces greatly to the clear, generous spatial impression: the displays of the information and control system are visible at the point farthest forward in the interior, but, optically, appear a bit further away, because at the bottom edge of the windshield there is a mirror; the display itself is horizontally retracted into the cockpit. This technology not only makes for a very clear and tidily arranged instrument panel. Owing to the bigger distance between the driver’s eyes and the display as compared with a conventional cockpit, the need for the eyes to adapt their range for far and near vision is appreciably smaller. This reduces eye fatigue and makes a scientifically verified contribution to greater stress-relieving safety.

The F 700 provides inspiring ideas for the technological future of Mercedes-Benz once again – like each of the research cars which preceded it.