The latest Volkswagen Golf boasts an impressive 100-kg weight loss versus the previous model. It's based on the automaker's Modular Transverse Matrix (MQB, modularen Querbaukasten); a component matrix that enables design of a variety of transverse, front-engined, front-wheel drive models using the same set of components.
The new Golf; lighter and larger thanks to steel, and a dollop of plastics.
I was expecting plastics to have played a major role in achieving this weight reduction, particularly given weight savings attributed to the car's superstructure came in at 37 kg, but reading through the extensive announcement about the seventh-generation Golf I barely heard plastics mentioned.
For the superstructure, the reductions came as follows:
- 0.4 kg = Dashboard. Volkswagen achieved a 20% lighter dashboard thanks to a new thermoplastic foam injection process—the load-bearing, sandwich-like structure beneath the elegant surface consists of this material—which also achieved a 20% higher rigidity.
- 1.4 kg = Module cross-member (beneath dashboard). Mounted on the module cross-member are both the steering gear and the dashboard. Altogether the cross-member weighs in at 5.8 kg. The reduction in weight was achieved with a lightweight construction concept using steel components and employing finite element method (FEM) analysis to optimize strength and weight. Optimal steel wall thicknesses and structural design measures, such as specially worked-in corrugations, improved the rigidity of the cross-member, while also contributing to reducing its weight by 1.4 kg.
- 2.7 kg = Air conditioning. The Golf's entire air-conditioning system was redesigned and consequently 2.7 kg lighter. The mass reduction is achieved by such design modifications as optimized thickness of various system components walls, reduced diameters of pressure lines, a new fastening system and a weight-optimized high-performance heat exchanger (I detect some plastic participation here).
- 7.0 kg = Front and rear seats. Along with numerous minor modifications to the seats, weight was reduced—especially from the rear backrests—to save a total of up to 7 kg. Here, too, the FEM and high-strength steels combined with laser welding realized optimized wall thicknesses and profile geometries. Engineers achieved weight savings of more than 15% through this and by using lighter backrest latch mechanisms.
- 23.0 kg = Body. The body must be strong and rigid to guarantee optimal safety and maximum comfort. Nonetheless, its structure should remain lean, so that the overall vehicle is light. Optimizing the strengt-to-weight ratio continues to be one of the greatest challenges in the automotive world according to VW. Highly expensive materials like aluminum, magnesium, or even carbon-fiber are therefore excluded in the mass-market Golf segment. Instead, Volkswagen relies on the synergies of MQB, innovative utilization of high-strength steel, and advanced production methods. The result is a 23-kg reduction in weight with more stringent crash and rigidity requirements as well as larger vehicle dimensions.
- 2.5 kg = Miscellaneous.
So there you have it. I'd be interested to know how much more progress is anticipated of steel and what the long-term plans are for plastics and their composites.