Vehicle: Mercedes-Benz Vario Research Car
Introduced in: 1995
Where: Geneva Motor Show
Goals: Variable vehicle concepts, ergonomics
Powertrain: Front-wheel drive, continuously variable automatic transmission
Swap bodies: saloon, estate, convertible and pickup on one and the same chassis, exchanged within 15 minutes
Light and sturdy bodies made of carbon-fibre reinforced plastic (CFRP)
Active Body Control (ABC)
Production launch in the Mercedes-Benz CL (1999, C 215 series)
Colour display Production launch in the Mercedes-Benz S-Class (1998, W 220 series)
Central rotary control for the electronic functions
Production launch in the Mercedes-Benz S-Class (2005, W 221 series)
Navigation system Production launch in the Mercedes-Benz S-Class
(1995, W 140 series)
Safety display coupled to traffic sign evaluating function and distance warning radar
One car, four vehicles – variability is the emphasis of the design of the Vario Research Car (VRC) by Mercedes-Benz, which attracted great attention at its premiere at the 1995 Geneva Motor Show. For in just a few minutes, the VRC can be converted into a different car. Whatever trip you plan, you will not need more than one car thanks to the variability of the body of the Vario Research Car. On weekdays it’s a saloon. For longer journeys, the load capacity of an estate is available. In the summer the sun invites you to take an open-top ride in a convertible. And for heavy loads, there’s the pickup with its open cargo space.
Mercedes-Benz solved the problem with a compact two-door car. It features a single-piece body consisting of roof, side walls and rear section; the body can be lifted off and exchanged for another variant. Doing it calls for a few simple operations and only about 15 minutes’ time. The Vario Research Car was combined with a vision: customers do not own the bodies themselves but drive up to a rental station. While they drink a cup of coffee, service technicians switch the body. A few minutes later, customers are back on the road again. How long they use a particular body variant is up to them, because the rental system is just as flexible as the car itself.
One car for different activities
Futurology provided the impetus for the Vario Research Car. The prediction is that people will have more leisure time which they will employ for different activities. For these activities, and for everyday use, they would like to choose a vehicle to fit their purpose. But having one’s own little fleet would not be economical. The Vario Research Car from Mercedes-Benz offers the solution.
On top of that, the VRC illustrates clearly that research vehicles demand a dialogue with the public: Mercedes-Benz requests drivers to state their opinions about each new concept. In the case of the Vario Research Car, the response has been particularly extensive and unusually diversified. From this response, Mercedes-Benz obtained numerous valuable suggestions for future production models.
This research car too features a number of forward-looking technical solutions. The body change should be easy to accomplish. Only the interplay of several components can make this possible. The service technicians place the roof structure on the chassis; electric motors pull it into its final position, where special locking mechanisms hold it at eight anchorage points. To release it, it suffices to actuate levers on the door pillars and the upper windshield frame. The rest is again done by the servomotors which undo the locks and slightly raise the body so that it can easily be lifted off.
For the electric connections in the rear, which differ for each body, there is a central terminal which automatically recognises the type of body. If, for example, an estate body is mounted, the rear-screen wiper/washer will be supplied with current. In the saloon, the heated rear screen and trunk lights have to be connected to the electric system. In the convertible, the electric drive for the soft-top requires energy and has to be controlled.
Bodywork made of new materials
The bodies are light and sturdy – a result of the new materials tested by the engineers. They are made of the high-tech material CFRP – carbon-fibre reinforced plastic. Compared to aluminum, CFRP is 25 per cent lighter and, what is more, features high strength. The bodies weigh only 30 to 50 kilograms each and, despite their lightweight design, afford a high level of stability and crashworthiness. The Vario Research Car served to further test front-wheel drive in a Mercedes-Benz, which was combined with continuously variable automatic transmission as well as active suspension (Active Body Control, ABC) for improving handling safety and comfort.
The cockpit contains a colour display which shows the driver all the required information. On the centre console a rotary actuator is installed with which the driver can selectively control the entire menu. It includes not only rev counter, trip computer and trip odometer, but also the route recommendations of the onboard navigation system. A special feature is the safety display in combination with a traffic sign evaluating system. If the driver keeps to the official speed limit, it shows a green circle. If he or she drives faster or does not keep a proper distance from the vehicle ahead, the colour and shape of the symbol change – the circle turns into a yellow ellipse or a red triangle depending on how much the driver exceeds the speed limit or falls below the safe distance. For this function, the onboard electronics are coupled with distance radar and traction control.
The upper part of the centre console accommodates a second display where, among other things, information on the settings of the air conditioning and navigation system are shown. When the driver stops to refuel, he or she is also told whether the tyre pressure, the levels of engine oil, coolant and wash water, and the light system are okay. While on the go, drivers are prevented from choosing additional functions, so as not to distract their attention from traffic, while front passengers have unimpeded access to all secondary information. To tell the difference, the rotary control “senses” whether it is being touched by the left hand (front passenger) or right hand (driver).
First-time use of drive-by-wire for steering and brakes
The Vario Research Car was the first research car from Mercedes-Benz featuring drive-by-wire technology, in which the steering and the brakes, for example, are actuated electrically with no mechanical linkages existing to the steering hands and braking feet. But the testing of this technology was not the main purpose of the VRC – the variability of the body was the principal concern. With the Vario Research Car, Mercedes-Benz underpinned its forte, the holistic design of new vehicles – and its ability to put them on wheels in fully operational condition.