Mercedes’ little luxury

Mercedes’ new supermini is a departure for the classy car maker – and its unique double floor breaks new ground in small car safety, reports Arlene Foster

Safety, space and more than a dash of style are the overriding features of the new A-class from Mercedes-Benz.

The luxury car manufacturer has broken much fresh ground with this new breed of supermini which goes on sale in the UK next spring. Not least is Mercedes’ bold move away from its traditional premium car market into the small car sector. But equally important is its innovative approach to small car safety.

It was the threat of added competition from its rival BMW that persuaded Mercedes to move into what it calls the compact car segment. When BMW bought Rover in 1994, Mercedes realised that it would have to increase production to keep up, and set a goal of producing and selling over one million cars a year.

The A-class will boost its annual vehicle production by 200,000 to around 800,000 and, claims Mercedes, will stimulate a growing demand for small, safe and environmentally friendly cars. Production will take place at Rastatt in Germany and in Brazil, where Mercedes hopes to open up new markets and win new customers.

In the UK it will sell for between £13,000 and £18,000 – expensive by small car standards, but a snip compared to other cars in Mercedes’ range, which can cost up to £100,000. The company reckons customers will be prepared to pay extra for the 30 safety and comfort features, not to mention the considerable cachet of the Mercedes brand. It hopes to sell 16,000 to 18,000 vehicles here a year.

The technological innovations are impressive. When it comes to safety, Mercedes has adopted a unique approach.

`Safety is not an isolated component or just a question of putting in a few airbags. It’s a well thought-out integrated process,’ says Ingo Kallina, vice-president of car components, structure and safety.

Central to this a unique sandwich floor pan and slimline engine. Small cars are inherently less safe than larger vehicles because of their lower mass and short length, leaving limited space for the front end crumple zone which absorbs energy in a controlled way in a crash.

In designing the A-class the main aim was to maximise the extent of the crumple zone by clearing away the engine and gearbox, which, being essentially solid, obstruct the controlled deformation process.

Although the car is only 3.6m long, the double floor allows the transmission, axles and fuel tank to be mounted underneath the passenger compartment. The engine is mounted at a slant of 59 degrees just in front of it. In a frontal crash, it slides under the passenger compartment rather than straight back into the passengers.

The raised floor also means that passengers are seated above the normal side impact zone, affording them greater safety in such a collision. The vehicle not only satisfies the EU crash standard for a frontal impact – due to come into force in 1998 – but also complies with the strict safety standards in the US and the EU for side impact collisions.

Putting the engine and gearbox underneath passengers is also the key to creating the roominess. Some 70% of the exterior length can be used for passenger and boot space. The interior length is just four millimetres short of the Mercedes C-class and it can quickly convert into an MPV by removing all the seats but the driver’s.

Total effective cargo space is 1700 litres with the seats out. While the seats are in place, passengers can have 72 seating positions.

Although Mercedes is in talks with other vehicle manufacturers about selling its sandwich floor design, it will not be incorporated in any of its other models.

`This is a unique design for short cars,’ says Kallina.

Mercedes spent DM1.5bn (£555m) in developing the A-class over a period of about two and a half years, which is comparatively quick and inexpensive by Mercedes standards. `It was a real challenge to make this car behave and feel as a Mercedes should,’ says Alfred Kist, who was responsible for the technology and development.

`We know how to build cars but this is our first in this price segment and we had to design the car to the target cost per vehicle of DM30,000 (£11,100). That was another challenge.’

About 80% of the components are German but British firms did win contracts to supply the axles and louvre sun roof. To keep costs to a minimum Mercedes designed and built its own components where possible.

This is true of the lightweight aluminium engine which, as well as being an integral part of the safety process, contains other groundbreaking features, not least its slimline appearance. `It took several test runs to get the engine size right for the double floor,’ says Kist.

It was worth the effort, however. Only through the success of Mercedes engineers in designing an engine suitable for an underfloor oblique-angled installation was the sandwich principle and its associated high safety potential made possible.

Four new four-cylinder engines have been developed for the car with power ranging from 80-102bhp. Petrol engines of 1.4 litre and 1.6 litre capacity will be available when it goes on sale this autumn in Germany; next year 1.6 litre and 1.7 litre turbodiesels will be added.

These will feature the first use of direct injection using the common rail principle developed by Mercedes in conjunction with Bosch. This basically allows the right amount of fuel into the engine at the right time, leading to reduced noise and improved fuel consumption.

Average fuel consumption figures will range from 41-63mpg depending on model. The engines have low exhaust emissions, up to 40% below the EU limits.

The raised floor also allows sufficient space for energy storage units of future alternative drive systems including batteries, or a hydrogen tank for a fuel-cell car.

In designing the A-class Mercedes claims that it is not simply extending its product range but developing a trend-setter. Certainly other manufacturers, including BMW, are taking note – hence Rover’s decision to show its new Mini concept cars at this month’s Geneva motor show, stealing some of the limelight from the A-class’s launch.

Despite its lack of experience of small car production, being first with a new concept may be enough to give Mercedes a headstart on the competition – as did the Mini 40 years ago.