F 400 Carving | Daimler > Technology & Innovation > Insights into Research & Development

F 400 Carving (2001)

The F 300 Life Jet research vehicle provided extensive insights into the active wheel chamber control for cars. The engineers then systematically extended their research work to a four-wheeled vehicle and, in 2001, presented the F 400 Carving. In particular, its systems enhance handling safety, driving dynamics and motoring pleasure.

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Safe driving pleasure – the F 400 Carving

The most conspicuous feature of the F 400 Carving, which gets its name from the sporty carvers on ski slopes, is the tilting of its wheels. When cornering, the wheels on the outside of the bend tilt by as much as 20 degrees, which distinctly improves directional stability and roadholding, and reduces the danger of skidding. Electronics have been combined with mechanics to achieve this. Sensors measure the road speed, acceleration, steering lock and yaw of the car, and send control signals to the outer wheels’ hydraulic servo cylinders, causing them to tilt at a precisely defined angle. The kerb-side wheels, like the body, remain in their normal position.

Facts

Introduced in	2001
Where	Tokyo Motor Show
Goals	Testing of novel dynamic handling systems
Powertrain	Viertakt-Ottomotor mit 12 Zylindern, 6,0 Liter Hubraum, 300 kW (408 PS), Heckantrieb, 6-Gang-Schaltgetriebe

Technical Highlights

Active camber control

Electronic steering system (steer-by-wire)

Electronic brake system (brake-by-wire)

Production launch under the name Sensotronic
Brake Control (SBC™) in the Mercedes-Benz SL
(2001, R 230 series)

Active hydropneumatics with a new type of Active Body Control (ABC)

Brake discs made of carbon-fibre reinforced ceramic

Production launch in the Mercedes-Benz CL 55
AMG F1 (2000, C 215 series)

Aluminium space frame with CFRP body (carbon-fibre reinforced plastic)

Aluminium-Spaceframe mit CFK-Karosserie
(Kohlefaserverstärkter Kunststoff)

Xenon headlights incorporating fibre-glass technology

Additional headlights for cornering, also operating as fog lamps

Production launch in the Mercedes-Benz E-Class
(2002, W 211 series)

Turn signals with high-performance LEDs

42-Volt-Bordnetz

Active camber adjustment for enhanced safety

Thanks to the F 400 Carving’s active camber control, the cornering forces, compared with a contemporary car chassis, are up to 30 percent higher. Longitudinal forces are improved by up to 15 percent. Due to high lateral forces acting on the outer wheels, lateral acceleration is up to 28 percent higher than with sports cars built on conventional chassis technology. This solution not only affords more dynamic cornering and sporting agility, but also improves handling safety. This applies in critical situations in particular, such as taking bends too quickly or swerving suddenly.

The risk of skidding caused by under or over-steering is eliminated by means of efficient hydraulics. The system tilts one or more wheels briefly and to a precisely computed angle, which increases the cornering forces and stabilises the vehicle. For emergency braking, all four wheels can be cambered in a flash so that only the insides of the tyres, with their friction-optimized tread compound, have contact with the road. This shortens the stopping distance from 100 km/h by a good five metres. The chassis technology also has the ability to change the tyre contact patch if aquaplaning threatens.

Special tyres for the research car

The success of the F 400 Carving is attributable, in major part, to its tyres. These were developed specifically for this car and combine the advantages of car tyres with those of the motorcycle. The inner tyre has a rounded tread to allow best cornering behaviour; this tread also has an especially high coefficient of friction. When the wheels are tilted, the transmitted forces are particularly high. The outer shoulder of the tyre features a proven car tread and good straight-line stability. The tyre is mounted on a special rim with a diameter of 17 inches on the inside - the active cornering side, and an outer diameter of 19 inches. This ensures that, on a straight stretch, the research car drives on only the part of the tread that is not arched. On bends, thanks to the smaller inside diameter, the largest possible tyre contact patch is ensured.

Advanced electronics

Drive-by-wire technology was a further development goal of the F 400 Carving. The F 400 Carving does not have a mechanical linkage like a steering column, with its spindles and joints, or links between the brake pedal and brake booster. Instead, cables transmit the driver’s steering and braking commands solely by electronic means. This allows for additional safety. In hazardous situations, automatic steering correction reduces the risk of skidding. The electronics compute and, as required, apportion brake pressure to each wheel according to the situation, thus ensuring highly reliable braking on bends, for example.

Carbon-fibre reinforced ceramic brake discs

The brake discs are made of carbon-fibre reinforced ceramic, a high-tech material which resists extreme temperatures in the range of 1,400 to 1,600°C and permits optimal deceleration. In addition to the standard onboard power supply, the F 400 Carving is equipped with two 42-volt systems, mainly for the electronic steering.

Suspension and lighting

The F 400 Carving features a new kind of Active Body Control (ABC) coupled with an active hydropneumatic system. This influences both the springing and damping of the car. The result, once again, is enhanced handling safety and better ride comfort.

The headlight system is another new development. The light source and headlight proper are separate – glass fibres transmit the combined light of the xenon bulbs to the apertures without loss, where it is distributed across the roadway by special lenses. This has special benefits for the design of the sports car’s front, because the headlights occupy very little space. On bends, depending on the angle of the wheels, additional side headlights switch on; they also function as fog lamps. The indicators are high-performance light-emitting diodes, whose light is distributed by prismatic rods.

Research into materials was also undertaken for the F 400 Carving. The body is made of carbon-fibre reinforced plastic (CFRP) and weighs just over 100 kilograms. The space frame chassis is made of steel, aluminium and CFRP. The F 400 Carving roadster brings back the gullwing doors – a distinctive characteristic of special Mercedes-Benz sports cars.

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