Appointment with the future
- Major space savings with innovative pedals
- Programmable multivision display and infrared nightview system
- High-performance combination of V8 diesel engine and electric motor
At the Tokyo Motor Show 2003, Mercedes-Benz presented the latest in a string of research vehicles which have attracted much interest and attention over the years and which provide fascinating insights into the automotive technology of tomorrow and beyond. Packaged as a stylish fastback saloon, this pioneering vehicle showcases more than a dozen technical ideas for enhancing the safety, drive technology and comfort of future Mercedes passenger cars.
Researchers will be using the four-door saloon to conduct the first practical tests of various innovative systems and to pave the way for their introduction into series production. The F 500 Mind is therefore designed as a mobile research laboratory, and is fitted with a lavishly equipped laboratory bench on the passenger side of the vehicle. The bench folds out towards the rear and can be operated from the right-hand single seat at the back of the car.
The bench incorporates computers for monitoring the F 500 Mind’s onboard systems, controlling a vast array of functions and carrying out online measurements during tests on the proving ground. Measuring 5092 by 1889 millimetres, the research vehicle is 49 millimetres longer and 34 millimetres wider than the current S-Class. The biggest difference however is in terms of height. At 1534 millimetres, the F 500 is 90 millimetres taller than the range-topping Mercedes model.
Inside the F 500 Mind, the completely new spatial environment and lavish roominess come as something of a surprise. This is due to the replacement of conventional mechanical accelerator and brake pedals by pressure-sensitive electronic controls. Each of these electronic pedals incorporates eight sensors which measure the accelerator or brake pedal effort and relay it as an electronic signal to the control units in the engine or the SBC™ brake system.
This innovative technology allows finely controlled acceleration and braking with short response times. It also takes up very little space, extending the length of the front footwell by 120 millimetres, the distance which would normally be required for pedal travel. This 120 millimetres is put to good use in a redesign of the passenger compartment. The driver’s and front passenger’s seats have been moved 120 millimetres further forwards, thereby opening up a new dimension in spaciousness. The hip-to-hip distance between the front and rear passengers is 980 millimetres — an outstanding figure even for the luxury class.
Further advantages of the innovative, non-wearing pedal technology are a reduced injury risk in a frontal collision and reduced noise due to a closed front bulkhead. Also, the cruise control and SBC™ functions like Soft Stop, Tailback Assist or Anti-stall Assist can be operated even more easily – with a “click” of the electronic foot pedal.
Doors: flexible opening
The F 500 developers even came up with new ideas for more convenient entry and exit, in the form of two-way doors with conventional or centre opening.
With the conventional method, the large doors can be opened forwards to a maximum angle of 90 degrees, independently of each other. If even more convenient access to the rear is desired, the shortened B-pillar, which is normally connected to the door sill, can be disengaged, allowing rear-hinged opening of the rear door together with the B-pillar to an angle of up to 90 degrees. This provides a large opening which measures 1900 mm across and is not obstructed by a B-pillar. The B-pillar is connected to the body by means of an electromechanical locking system which can be disengaged electrically simply by pressing a button.
Body structure: central pillar inside the vehicle
The unique two-way door technology and the absence of full-size B-pillars presented the researchers with something of a challenge when it came to ensuring the structural rigidity of the body. They had to find some other way of incorporating the important structural stiffening and crash safety which would normally be provided by the B-pillars. Larger-diameter roof pillars and roof frame members were not an option, since they would have impeded all-round vision and easy entry.
Eventually, finite element computer analyses gave the Stuttgart engineers the idea of using a central interior pillar. The central pillar provides a sturdy connection between the transmission tunnel and the y-shaped roof structure. Together with a cross member in the floor and strong sill members which come into play in the event of a side impact, the central pillar provides high flexural and torsional rigidity. The new structural element was designed in accordance with an in-house study which showed that a slightly curved shape was the best way of ensuring good rearward and sideways visibility for the driver.
The interior pillar also offers some new ideas for the air conditioning system: the F 500 developers integrated air conditioning ducts into the pillar trim and routed them upwards to the centre roof member. Here they have fitted individually adjustable ventilation outlets for the rear passengers. Also located in the interior pillar are special lighting panels, which together with the indirect lighting on the transmission tunnel provide discreet but effective interior illumination.
Control and display concept: multivision technology for the cockpit
The cockpit of the F 500 Mind contains numerous innovations which assist the driver in operating the vehicle and which supply important information in clearly arranged form.
The centrepiece of the instrumentation and control system is the newly developed multivision display incorporating the speedometer, rev counter, navigation display and various other instruments. The innovative technology allows the driver to individually programme the display so that he has a view of all the information he requires. He can change between displays simply by pressing a button on the steering wheel.
The multivision instrument panel combines high-resolution TFT (Thin Film Transistor) displays with analogue dials. The displays form a large and logically organised array which can display as much information as the driver requires. Using a semitransparent mirror which extends right across the instrument cluster, the circular dials and the displays can be optically superposed or shown separately. Depending on how the system is programmed, the displays can also incorporate the dial lettering. Basically, the multivision principle means that a single display can present various different sets of information, dispensing with the need for additional displays or dials.
The movement of the lighted needles in the dials can also be programmed. As well as speed, rpm and energy consumption, other information can be shown here too. If the driver switches off the dial and needle lighting, the relevant display area can be used to show menus or images from the infrared nightview system.
The needles and dials are positioned in such a way that they appear to float in front of the display. This creates an interesting three-dimensional effect.
Touchpad in centre console plus new sensors
Further settings can be performed on the central display unit, which is situated above the centre console and is connected to a touchpad . By briefly pressing this touchpad, situated in front of the centre armrest, the driver can select and operate various different control functions on the display, including navigation, audio systems, telephone, air conditioning and much else besides.
The advantage of this technology is the direct correspondence between the touchpad and the display: the controls on the touchpad are structured in exactly the same way as the control panels in the central display, allowing the driver to control functions intuitively, quickly and reliably. He can move his finger over the touchpad without looking at the display. Different areas of the display are highlighted instantly in response to the movement of the driver’s finger.
The conventional switches and buttons which are used on the F 500 Mind for controlling primary functions, such as seat, steering wheel and pedal adjustment or operating the air conditioning, likewise feature innovative technology designed for easier operation. When the driver moves his finger close to one of these controls, the appropriate system immediately appears on the display. The driver can then operate it using either the buttons or any other possibility offered by the particular system. The buttons and switches are equipped with special capacitative sensors which automatically detect the driver’s approaching hand even at a distance of about five centimetres. The appropriate display is then shown before the hand actually gets to the button or switch.
There is an even easier method available however, namely to operate the functions shown on the central display by voice control. The F 500 Mind is fitted with a further-refined version of the Mercedes LINGUATRONIC voice-operated control system which offers a new and extended range of choices. LINGUATRONIC is activated by pressing the talk button in the centre console. As instructed by the driver’s voice commands, it can then be used to control the radio, DVD player, navigation system, climate control or other systems. The functions shown in the central display automatically change in accordance with the commands.
The existing LINGUATRONIC system responds only to specific, standardised commands, like “start navigation” or “select radio station”. In the F 500 Mind however, the DaimlerChrysler researchers are testing a system which, as well as responding to approximately 200 standard voice commands, also understands commonly used synonyms and freely formulated sentences for the first time. For example the driver could ask the system to display the navigation map using a synonym more familiar to him, like “street plan”. The system also understands freely formulated commands like “I’d like to switch to air recirculation” or “I’d like to listen to a CD.” The newly developed LINGUATRONIC system then performs the necessary operations.
Ultrasound technology targets information directly at the driver
To manage sound-based information which is intended only for the driver’s consumption, like the voice instructions provided by the navigation system, up-to-date traffic news or telephone conversations, DaimlerChrysler researchers have developed an innovative ultrasound system which in the F 500 Mind is now undergoing practical testing for the first time. Inaudible, high-frequency ultrasound (100 kilohertz), which is highly directional and focused, serves as a carrier signal onto which the actual audio information is modulated. This information is initially inaudible and is only converted into an audible signal in the course of its journey from the loudspeaker to the driver’s ear.
The ultrasound beam targets the audio information precisely to the required location. This prevents other occupants of the F 500 Mind from being disturbed by navigation instructions or radio announcements which are of interest only to the driver. The system also allows occupants to conduct private telephone conversations or to listen to their own choice of music.
The system consists of 28 piezoelectric loudspeakers mounted on the inner side of the top edge of the front windscreen frame and directed at the driver’s head. The ultrasound is generated by a special amplifier with digital signal processor.
Holographic image projection in the rear
While the driver of the F 500 Mind listens to audio information tailored specifically to his or her individual needs, the rear passengers have access to an innovative holographic information and entertainment system which projects photos, computer programmes, video games, TV programmes or DVD films onto a transparent, low-reflection Plexiglas screen. This screen provides a bright, high-brilliance image for the rear passengers even in sunlight.
The system consists of a projector, installed between the rear seats, and a special projection screen. Unlike the more familiar types of hologram, this “Holdis Provision” system is not used for three-dimensional projection but utilises the advantages of holographic technology for projecting images under bright ambient light conditions. The image produced by the F 500 system can be projected with up to 40 times the brightness of conventional displays onto a precisely defined surface and is unaffected by ambient light. This makes it particularly well-suited to in-vehicle applications.
Nightview system: infrared laser with range of up to 150 metres in the dark
With an innovative infrared laser nightview system, the DaimlerChrysler researchers are aiming to further reduce night-time accident risks. This technology is now under-going further testing and development work in the F 500 Mind mobile research lab.
In the future the infrared nightview system will allow drivers to see much better when driving in poor visibility, even in the face of oncoming headlamps. The laser headlamps on the front of the F 500 Mind increase the driver’s range of vision when operating on dipped beam from the customary 40 or so metres today to over 150 metres. The infrared laser light is invisible to the human eye and thus does not dazzle oncoming drivers. It makes parked cars or other obstacles visible much sooner than in a vehicle fitted with conventional headlamps – particularly when there is oncoming traffic.
A video camera mounted on the inside of the front windscreen records the reflected image and projects it in black-and-white onto the multivision display. The image appears to the right of the speedometer and thus directly in the driver’s field of vision.
For the purposes of the nightview system, it is sufficient for the laser headlamps to emit extremely short light pulses at regular intervals. These light pulses are synchronised with the opening of the shutters on the highly sensitive camera, thus preventing the camera from being dazzled by the visible light emitted by oncoming vehicles. At the same time special filters in front of the lens ensure that the camera only receives as much light as is actually necessary. In the future, this innovative technology will be extended with a second camera which will allow it to operate as a stereo system and thus to provide enhanced hazard detection and driver warning.
High-performance light-emitting diodes for daytime driving lights
The dipped and main beams based on six powerful xenon projection-type headlamps and the daytime lighting based on 16 newly developed white high-performance light-emitting diodes (LEDs) with a special lens system were developed jointly with Hella. The front headlamps split when the bonnet is opened. On each side the top segment, which moves with the bonnet, includes the dipped headlamp, daytime lighting, direction indicator and one laser module for the night vision system. The lower segment, which is integral with the body, includes the main-beam headlamp and a further laser module on each side.
Two xenon headlamps with an output of 2 x 35 watts are responsible for producing the dipped beam. The light output of 1200 lumens provides extensive illumination of the road. The lenses in front of the projection system, and their delicate mountings, are triangular in shape, giving the xenon modules an innovative and highly distinguished appearance. Since the light beams are highly concentrated, headlamp performance is unaffected by the reduced size and triangular shape of the lens. For the main beams, the F 500 uses two more xenon projection modules, each with an output of 35 watts.
Eight high-performance light-emitting diodes on each side are automatically illuminated during daytime operation. They are directly connected to transparent plastic components which act as lenses and provide a wider light beam. As a result, despite having an output of just one watt each, the LEDs are clearly visible even from a distance. If the driver switches on the dipped headlamps, the electronic control system reduces the brightness of the LEDs. A further nine yellow-orange LEDs are used in each direction indicator.
Drive concept: V8 diesel engine and electric motor form high-performance duo
In the F 500 Mind, the DaimlerChrysler research team is investigating the practicality of an alternative drive concept in the form of a high-performance diesel hybrid drive system. The latest hybrid technology offers various alternative possibilities for combining two different power sources in one powertrain. In the F 500 Mind research vehicle, the engineers have combined the high-torque V8 diesel engine from the Mercedes-Benz S-Class with an electric motor mounted between the engine and the modified automatic transmission. This combination currently delivers more power and more torque than any other hybrid powertrain system for rear-wheel-drive passenger cars. The statistics:
- V8 diesel engine: 184 kW/250 hp, peak torque of 560 Nm (413 lb-ft)
- Electric motor: 50 kW/68 hp, peak torque of 300 Nm (221 lb-ft)
Electronically controlled load share apportionment between the diesel engine and the electric motor allows the hybrid vehicle to use the advantages of each form of drive to best effect. For example when moving off from rest, when parking, in stop-go or slow-moving operation, or when the vehicle is following the traffic flow with no major power demands, the electric motor takes over, providing emission-free operation. The diesel unit only cuts in to provide powerful acceleration if the driver demands more power. The hybrid diesel powertrain is capable of reducing NEDC fuel consumption by approximately 20 per cent. This impressive result has been achieved by a range of different measures. For example the diesel engine can be switched off at traffic lights, and the vehicle started again initially just on electric power. This function alone (engine shut-off and electric start-up) cuts NEDC fuel consumption by approximately ten per cent.
Energy recovery during braking brings further fuel economy benefits. As soon as the driver steps on the brake pedal, the electric motor turns into a generator, producing electricity which is used to recharge the drive battery. This feature reduces fuel consumption by between five and seven per cent. The electric motor is powered by an underfloor lithium-ion battery with a two kilowatt-hour capacity and a rated voltage of 300 volts.
Steering: data line replaces steering column
As can be seen from a glance inside the F 500 Mind, this latest research car to bear the Mercedes star challenges conventional notions even when it comes to the steering. The attractive multi-segment steering wheel, whose oval shape is somewhat reminiscent of the yoke used to steer an aircraft, is part of a complex electronic steering system. Mechanical components like a steering column with spindles and joints are absent. Instead the driver’s steering commands are transmitted by cable to two electric motors. The motors use toothed belts to operate an electric rack-and-pinion system.
With this technology, the steering is fully adapted to the hybrid powertrain concept of the research vehicle: an electric rack and pinion does not have to be supplied with hydraulic fluid by the internal combustion engine. The energy for the steering system is supplied by the 300-volt battery of the hybrid powertrain. The voltage is transformed down to 42 volts.
The two electric motors driving the electric rack and pinion each contribute half of the steering moment. In the event of a fault, the system can continue to function on just one motor. This use of redundancy ensures maximum reliability. Duplicate – and even, in the case of the steering angle sensors, quadruplicate – components are used in other areas of the electronic steering system too, in the interests of safety.
The fact that the steer-by-wire system dispenses with a steering column and other mechanical linkages allows new functions to be offered for more comfortable entry and exit. As soon as the driver removes the electronic ignition key of the F 500 Mind, the steering wheel slides 140 millimetres to the right, automatically moves to its highest position and then turns by 45 degrees, thus offering particularly easy egress. A memory function retains the individual settings.
Chassis: SBC™ with electric parking brake
The brake system and chassis of the F 500 Mind conform to the high technological standards associated with Mercedes passenger cars. The research vehicle is fitted with the proven Sensotronic Brake Control and AIRMATIC DC systems used in the E-Class.
A further feature is the electromechanical parking brake, which offers increased driver convenience. Operated simply by pushing a button, it acts on separate drum brakes at the rear wheels.
