<<BACK TO HOME

More testing and closer work with suppliers has improved quality on the latest Mercedes-Benz C-Class, which will raise buyers’ perceptions of the level of engineering and equipment in the D/E sector.

By Tristan Honeywill

Who supplies the C-Class? Click here...

DaimlerChrysler is not having an easy time. The problems at Chrysler are well known and quality issues at its Mercedes-Benz division in recent years have affected the brand’s standing.

Competition with BMW and Audi was tough enough, but more OEMs are developing premium models that threaten its traditional market. Mercedes needs good products to re-establish its reputation for quality. The C-Class is key.

The Baby-Benz is the marque’s highest volume model. The previous version sold more than two million units since 2000. The new W204 series contains a lot more technology than the W203, but Mercedes has worked closely with suppliers to achieve the vehicle’s starting price of €30,000.

The engineers’ task on the C-Class is harder in some ways than on other Mercs. Developing an E-Class involves integrating a lot of first-time technologies into a luxury car. It’s challenging, but the brief is focused on luxury and the cost constraints are different. The C-Class is a smaller, less expensive car.

“There is also a greater variety of customers,” says development chief Markus Hauser. “And we had to develop a platform that combines comfort and sportiveness. We had to meet all the targets – there are many – and find a compromise.”

Mercedes relied on greater simulation work to ensure that the costs were right and the quality was higher than before. “The digital mock-up was far bigger than anything we’ve done before,” says Hauser. “Suppliers did far more hardware in the loop and durability testing earlier in the processs and provided much more data.”

The active suspension is an important part of making the usual trade-off between comfort and sportiveness less of an issue. The shock absorbers’ hydraulics change according to the driving situation. Damping forces are electronically reduced when driving normally. As the inputs into the chassis increase, an ECU increases the force.

Mercedes' Baby-Benz

Driving the car at its launch in Spain in heavy rain on winding mountain roads, it was hard to notice any compromise. Despite standing water and side-winds, cornering at speed was secure and motorway driving comfortable.

A new rear-axle concept achieves a consistent reduction in the accelerated masses in the chassis. In the W203, the knuckle was a cast part. The W204 uses a forged aluminium part instead. Supplied by Hirschvogel, the knuckle bears the parking brake with protection sheet, the service brake system and the wheel bearing.

On the inner side of the vehicle, four links and the spring suspension are fastened via an elastomer bearing and a suspension ball joint. NVH quality is improved in several ways. Structural bonding improves the stiff body’s sound absorption, while Mercedes worked with Eberspaecher on the gasoline exhausts’ sound. Behr developed two HVAC modules for the vehicle, significantly enhancing the climate comfort characteristics of the new model compared with its predecessor.

A two-zone module is supplied as standard, and a three-zone system is also available as an option. The three-zone module involves more complex technology, and is a first in this vehicle class. Despite the higher level of electronics in the car, the car weighs the same as its predecessor.

The body shell weighs 8kg less, thanks to greater use of high tensile steels and aluminium. Mercedes also avoided adding unnecessary bulk by using customised wiring harnesses. These contain only the cables, plugs and connections required for the configuration of the specific vehicle.

The OEM worked with Delphi on the development, which supplies three large wiring harnesses for the engine compartment, centre console and interior. The firm also supplies the satellite and digital radio receivers, integrated antenna, passive-occupant detection system, security sensors and the common rail injection system for the 220 CDI model.

The C-Class also uses the control and display concept first adopted in the luxury class models. The firm has updated its infotainment system and voice activation, developed in partnership with Harman/Becker.

The vehicle’s safety concept features an adaptive brake light as standard that flashes rapidly during harsh high-speed braking, to alert other drivers to the hazard. The Pre-Safe system, introduced in the 2002 S-Class, is available as an option. It uses the ESC and brake sensors to detect critical driving manoeuvres at an early stage.

If a crash looks likely, it starts to tension the seat belts, adjust passenger seats so that if the airbags fire they are in the best possible position and the loads acting on the head and neck are reduced by around 30 per cent. It can also start to close windows and the sunroof. The system is a first in the D/E segment.

Takata Petri supplies the driver, passenger and knee airbags, Autoliv the side airbags and the seat-belt pre-tensioner system. Grammer supplies crash-active headrests that reduce whiplash injuries.

To prevent electrical short-circuits and therefore a possible fire, the car uses a Delphi safety fuse in the connection between the battery and the starter generator. A pyrotechnic cuts the power supply. To reduce the risk of head injuries to pedestrians, the bonnet of the new C-Class is designed to deform.

The front bumper systems are designed so that a pedestrian involved in a collision at up to 55 km/h can roll over the bonnet without suffering serious injuries. Developed by Rehau, the lower section of the front bumper is relatively hard so that the pedestrian’s legs are slightly raised and they roll over the bonnet.

To improve repairability, the front end has an extruded cross-member with two aluminium crash boxes. At speeds of up to 15km/h, any deformation is limited to these parts. Bolted together, repairs are faster and do not require welding.

The car will be built mainly at three factories, Sindelfingen and Bremen in Germany and East London in South Africa. The Sports Coupé will be produced in the Juiz de For plant in Brazil. The Beijing-Benz facility in China is also likely to produce the car.

Mercedes has declined to reveal sales forecasts or production capacities at the plants. What we do know is that the firm expects it to do better than its predecessor.

After launching in May 2000, the W203 sold 270,000 units in its first seven months. In 2001, annual sales reached 506,500 units, declining by around 30,000 a year. In 2004 the car a mid-life face-lift increased annual sales to 470,000. In June that year, sales of 45,000 meant that the German plants reach their production capacities. In 2005 and 2006, volumes were 402,000 and 332,000 units respectively.

It has to sell well. DaimlerChrysler is relying on Mercedes for support as it restructures Chrysler and decides what to do with the loss-making US division. As a standalone business, Mercedes in any case needs to improve its capacity utilisation and profit margins.

“The car marks Mercedes’ return,” says Mann. “We’ve come back to our traditional values of quality.” It will also mean that other OEMs, wanting to position themselves at the premium end of the segment, will have to offer buyers a lot more technology for their money.

Who supplies the Mercedes C-Class?