18/11/11

Overview: Volkswagen Nils

Nils is a single-seat electric concept vehicle. The concept car features an aluminium space frame, wing doors and ‘free-standing’ wheels.

The Nils project is supported by the German Federal Ministry of Transport, Building and Urban Development, and is designed to be both technically realistic and economically supportable. The goal of the project is to research a technically concrete and economically feasible vehicle for what Volkswagen describes as ‘micromobility’. It has a range of 40 miles and a maximum speed of 130km/h (80mph), and its creators believe it would be the ideal vehicle for the majority of commuters in Germany. According to the German Bureau of Statistics, 73.9 per cent. of all commuters who live between Berlin and Munich cover less than 25km on their way to work. Being a single-seat vehicle, though, it does rather preclude car-sharing...

In Germany about 60 per cent. of all commuters travel by car; of these, over 90 per cent. travel alone. Whether they should be prevented from doing otherwise is a moot point.

The Nils is a very compact car: it is 3.04m long, making it about 50cm shorter than the new Volkswagen Up. It’s also extremely narrow, at 39cm from wheel to wheel, and 1.2m tall.

The basic layout is the same as a Formula 1 racing car, with the driver in the middle, the engine behimnd, and outboard wheels. The 17-inch alloy wheels are equipped with 115/80 (front) and 125/80 (rear) low rolling-resistance tyres. The styling was the responsibility of the Volkswagen Design Centre in Potsdam, under Thomas Ingenlath. The two glass wing doors allowed the designers to create large transparent surfaces and simultaneously to make entering and exiting the vehicle comfortable, even in cramped of parking spaces.

Kerb mass is quite low, as you might expect of such a minimalist vehicle — 460kg — and standing-start accelerating to 100km/h apparently takes less than 11s. The electric motor has a quite modest 20PS nominal steady power output, with a short-term peak power of 34PS. Torque peaks at 130Nm, available at the first revolution. A single-speed reduction gearbox is used, and ESP is provided. The lithium-ion battery has a capacity of 5.3kWh, which allows for a (quoted) driving range of ‘up to 65km’. A battery of this size is relatively inexpensive, and can be charged using either a conventional 230V electrical outlet — a full charge taking two hours — or at an electric vehicle charging station. The socket is located at the back underneath the rear lighting module.

The centrepiece of the electric drive system is the lightweight 19kg electric motor together with its transmission and battery-pack. Energy management uses a high-voltage pulse inverter, which — together with the 12V DC/DC converter for the vehicle electrical system and the charger — forms an integral drive unit. All drive unit components are located compactly in an aluminium housing at the rear of the Nils; drive is obviously to the rear wheels.

The motor, battery and all other components are so compact that there is still space for a small luggage compartment at the rear.

The steering is unassisted, because of the car’s low kerb mass. Suspension is by double wishbones front and rear.

The Nils is fitted with an automatic distance control system, which uses radar sensors to scan the space in front of the vehicle over a distance of about 200m. Brake interventions prevent the stopping distance dropping below a specified minimum value. The system can automatically brake the car to a stop, depending on the situation. Like any vehicle with brake energy recovery, considerable ‘engine’ braking is available when the motor acts as a generator.

A system called Front Assist is integrated in the automatic distance control system. This continually active system warns the driver of a potential collision; at speeds below 30km/h (18mph), automatic braking can avoid a collision under some circumstances.

The instrument cluster is an 18cm TFT display. The vehicle’s speed is shown digitally in the middle, while energy flow is represented by bars. Another graphic display offers information on the driving range. The second central instrument is a mobile multifunctional device like the one used in the new Up — the Portable Infotainment Device (PID). It is snapped into the A-pillar to the right of the instrument cluster. Using the touch-screen, the driver controls functions related to navigation, radio, media, telephone, trip computer, and — to preconfigure the driving range — ‘Eco’. The PID computes the expected driving range; it then displays not only the route on the map display, but also the radius and thereby the destinations that can be reached using the current battery charge.

To save on weight and costs, certain functional elements and controls do without electrical assistance. The side mirrors, for example, are adjusted manually. The heating and ventilation system has full electronic control though, and there is seat heating. Located to the right of the steering column is the motor start-stop switch; this round switch is also used to select drive, neutral or reverse.

The aluminium space frame body was designed as a safety cell. The body-in-white is produced from extruded aluminium, cast aluminium and sheet aluminium. The roof frame together with the door mounts, a roll bar, the boot-space and the front bulkhead consist of high-strength sheet aluminium. Extruded aluminium is used in the side sills, the transverse profiles and the front and rear body sections. The front and rear side body are aluminium. Parts made of high-strength plastic include the bumpers and the trim panels on the side sills.

The frames of the wing doors consist of three main elements: an inner section, a crash reinforcement section and an exterior part. The door windows are made of lightweight, scratch-resistant, layered polycarbonate, while the windscreen is made of laminated safety glass.

The headlights are bi-xenon modules, while the indicator lights and daytime running lights are white and yellow LEDs. In the acrylic ‘glass’ of the rear lights, the light generated by LEDs is routed by transparent semiconductors which consume a minimal amount of power.

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