Vehicle: Mercedes-Benz F 500 Mind
Introduced in: 2003
Where: Tokyo Motor Show
Goals: Testing of hybrid drive, novel door and interior compartment concept, electronic driver information system
Hybrid powertrain: V8 four-litre diesel engine (184 kW/250 hp) in combination with an electric motor (50 kW/68 hp)
Hybrid drive (combination of diesel engine and electric motor)
Variable door concept with two different opening options
Electronic accelerator and brake pedal
Electronically controlled steering
Night view system with infrared laser headlights, Production launch under the name night view assist in the Mercedes-Benz S-Class (2005, W 221 series)
Novel operating and display concept
Driver information system based on ultrasonic technology
Folding lab table with computer for monitoring the vehicle systems
The future will never cease to be exciting. This is borne out by the Mercedes-Benz F 500 Mind which was presented at the 2003 Tokyo Motor Show. The four-door car, designed as a modern fastback saloon, served as a research lab on wheels and demonstrated over a dozen technical ideas for enhancing the safety, propulsion and comfort of future Mercedes-Benz passenger cars.
This begins with the hybrid drive, the first in the luxury car segment. It has the ability to utilise different propulsion energies. If a great deal of power is required, a V8 diesel engine with 184 kW (250 hp) drives the F 500 Mind and simultaneously charges the batteries, because the car also features a 50 kW electric motor that works by itself or jointly with the internal combustion engine. Engine and motor are perfectly coordinated by an electronic control unit on the basis of traffic situation and driving style. The electric motor, for instance, powers the car when the latter starts off, in stop-and-go traffic and in other situations in which the internal combustion engine does not develop its optimum efficiency due to its design principle. When the driver demands higher engine output, the V8 engine cuts in and ensures dynamic acceleration. The electric drive’s 300-volt battery, located underneath the passenger compartment, is recharged during braking. The result of this sophisticated engineering is fuel economy improved by up to 20 per cent, especially in city traffic, and significantly lower emissions compared with a conventional propulsion system. The concept of the F 500 Mind already anticipates future emission regulations.
Novel door design
The developers also came up with new ideas to make boarding and alighting even more comfortable. With the variable door concept, doors can be opened in the conventional way or in the opposite direction (the so called butterfly principle), as required.
In conventional mode, the large doors swivel forwards, independently of one other and through a maximum angle of 90 degrees. If more comfortable boarding is desired in the rear, the B-pillar – a shortened design attached to the side skirt – can be unlocked after the opening of the front door. Together with the rear door, this pillar then swivels backward through up to 90 degrees, thereby clearing a 1.9-metre-wide opening without the B-pillar being in the way. The B-pillar is firmly connected to the bodywork by means of an electro-mechanical locking system and can be electrically released by a simple push of a button.
Bodywork structure: Central roof pillar in the interior
The unique variable door concept and the omission of top-to-bottom B-pillars faced the research engineers with a great challenge in designing the body-in-white. Their task was to find an alternative to the B-pillars which usually render an important contribution to the structural rigidity and crashworthiness of the body. Roof pillars and frames with larger cross-sections were out of the question as they would have impaired the driver’s all-round view as well as the occupants’ boarding comfort.
Computerised simulations based on the finite-element method finally prompted the experts in Stuttgart to come up with the idea of a central roof pillar in the middle section of the bodywork. It serves as a sturdy link between the transmission tunnel and the Y-shaped roof structure. Together with the additional cross-bracing in the floor and massive side-skirt profiles which are particularly effective in a lateral impact, the central pillar affords high levels of bending resistance and torsional rigidity.
The novel structural element owes its special design to a study into the driver’s vision, specifically carried out for this purpose. The result: the slightly curved shape of the central pillar ensures that the driver’s view of the sides and the rear is not impeded in any way.
Over and above this, the idea of a central pillar offers new options in climate control. The engineers integrated air ducts in the pillar cladding, which run upward to the middle roof carrier where individually adjustable ventilation nozzles for the rear passengers are fitted. Special luminous surfaces which are also integrated in the central pillar discreetly and yet effectively illuminate the interior compartment together with the indirect lighting of the transmission tunnel.
The all-glass roof makes for a light-flooded interior compartment. With a body length of 5.09 metres and a wheelbase length of 2.97 metres, the car offers clearly more legroom in the rear than other saloons in this category. Progress comes in the form of novel electronic accelerator and brake pedals. They consist of force-sensitive surfaces with sensors which transmit the driver’s commands to the engine and the SBC™ brake system in the form of electric pulses. The greater the driver’s foot’s pressure on a pressure plate, the more vigorously the car is accelerated or braked. These novel pedals take up less space than conventional ones and hardly protrude into the interior compartment, thereby enlarging the front footwell by 12 centimetres. The driver’s and front passenger’s seats can thus be moved forward to provide more space for rear-seat passengers. At the same time, passive safety is enhanced as the pedals are not pushed into the interior compartment in a crash. The steering of the research car is electronically controlled as well.
Novel display and operating concept
The multi-vision display in the cockpit of the F 500 Mind forms the key element of a novel operating and display concept which offers drivers a wider range of information while at the same time relieving them of stress. The gauges on the display are freely programmable, and their pictorial information can be superimposed by means of a semi-transparent mirror or combined with each other. Hence, at the push of a steering-wheel button, drivers are able to call up numerous items of information which is always displayed well within their field of vision but without distracting them. Another display above the centre console is coupled with a touchpad whose controls are structured in the same way as the display. With this unit, drivers control the navigation system, car radio, air conditioning, phone and other systems simply by lightly tapping on the touchpad.
Other switches and buttons are fitted with special sensors which already identify the driver’s approaching hand at a distance of several inches. The central display then instantly switches to the relevant function so as to facilitate operation.
A further developed voice control system and a driver information system based on ultrasonic technology afford additional operational comfort. With ultrasonic technology, only the driver hears the navigation system’s instructions, traffic news and other acoustic information – the front and rear passengers of the F 500 Mind are not disturbed.
Night view system for enhanced driving safety in the dark
In the dark or under poor visibility conditions, the novel night view assist function is activated in the right-hand display of the instrument cluster. It consists of two infrared laser headlamps at the car’s front end, whose invisible light illuminates the road up to 150 metres ahead. A camera in the windshield of the F 500 Mind records these headlamps’ light as it is reflected by other vehicles, cyclists or pedestrians, and converts the signals into an unambiguous black-and-white picture which is shown in the multi-vision display. The driver thus becomes aware of potential danger spots much earlier than when relying on the standard low-beam headlights which illuminate some 40 metres of the road ahead.
Workplace on the passenger side
Being a research lab on wheels, the F 500 Mind is equipped with a special lab table which can be folded back and comes complete with a computer. The researcher traveling in the rear was thus able to monitor and control the vehicle’s systems during trial driving, and to carry out measurements. This is because the research car was used, among other things, for intensive acceptance tests on the novel operating and display concept, as well as for road tests with the diesel hybrid drive and the night view assist function.