Body: Intelligent lightweight construction

Jul 15, 2014
Thanks to innovative solutions, the bodyshell of the new C-Class Estate weighs less, provides the basis for outstanding vehicle handling and best noise and vibration comfort with exceptional rigidity, and offers a high level of crash safety.
Thanks to intelligent and innovative lightweight construction, the new C-Class Estate with its aluminium hybrid bodyshell as well as front wings, bonnet, tailgate, doors and roof panelling made of sheet aluminium weighs about 65 kilograms less than its comparable predecessor model. This makes it the "lightweight-construction leader" in its segment. Less weight pays dividends in multiple ways: fuel consumption drops by up to 20 percent with no loss of power and at the same time it makes a lower centre of gravity possible, which results in noticeably sporty, agile vehicle handling.
To achieve this, the Mercedes-Benz engineers used new lightweight-construction methods with the extensive use of aluminium, hot-formed steel components and ultra-high-strength steels - an unusual combination in volume-production vehicles. The proportion of these materials has therefore increased noticeably compared with the successful predecessor.
Previous model series 
New C-Class Estate
uminium (sheet metal and cast)
9% (4%) 
49% (25%)
Hot-formed steel parts  
3% (4%) 
8% (12%)
Ultra-high-strength sheet steels  
3% (3%) 
4%   (6%)
Figures in percent of surface area (percent by weight)
Apart from the weight, the Estate bodyshell sets new, challenging standards in many other respects – for instance with the high rigidity at the force transition points from the chassis to the body or with the NVH (Noise, Vibration, Harshness) characteristics. As a result, the ambitious goals regarding driving dynamics and noise level have even been exceeded.
To achieve this, the designers exploited, for instance, the greater design leeway offered by die-cast aluminium compared with steel. The body consists, among other things, of eight large die-cast components, which with conventional design would have to be made up of several steel parts. In this way a host of functions can be mapped in a single component and installation space put to optimum use. For instance, all shock absorbers at the front and rear of the vehicle are mounted on these kinds of complex, rigid aluminium die-cast components.
The tailgate on the Estate has an all-aluminium lightweight design. The die-cast inner component gives the tailgate outstanding strength and reduces the weight at the same time. The design options of die-cast components allow favourable use of the installation space as well as the integration of reinforcements. The sheet metal panelling is welded by lasers.
Safety takes precedence
In keeping with Mercedes-Benz traditions, the body is moreover designed for exemplary crash safety. The Estate not only meets all current national and international laws, but also all rating requirements as well as the more stringent internal Mercedes-Benz safety requirements, which are based on what actually happens in real-life accidents.
A high-strength safety passenger compartment forms the core of this concept. It consists primarily of high-strength and ultra-high-strength sheet steel and panels with graduated wall thicknesses designed to withstand specific local stresses. Many segments consist of hot-formed steels, which as the result of this production process become very hard and less deformable.
The high-strength safety cell is surrounded by specifically calculated deformation zones which have been extensively field-tested. Thanks to optimised dissipation paths and a combination of aluminium die-cast parts and ultra-high-strength materials, this set-up achieves outstanding crash test results (e.g. Euro NCAP) and guarantees maximum occupant safety.
Mercedes-Benz C-Class Estate (S 205) 2014, body
Mercedes-Benz C-Class Estate, technology, body shell, lightweight construction
Mercedes-Benz C-Class Estate, technology, body shell, lightweight construction