VW's Mix-and-Match Modularity

Article From: 3/1/2008 Automotive Design & Production, , Contributing Editor

As part of its goal to surpass Toyota in worldwide sales by 2020' the VW Group has revamped its development process around a flexible modular system capable of building an increasing number of vehicles with fewer resources.

Cars as diverse as Audi's A4 and Bentley's Continental GT will be built off of the MLB architecture, while VW's volume models will share the MOB structure.

The MHB structure will use laid-over inline engines in VW's planned Up! minicar lineup.

New CAFE standards in the U.S. Tighter CO2 regulations for Europe. Doing more with less. These are some of the major hurdles facing the VW Group that directly affect its global product development process. Leveraging global resources not only reduces costs' it opens up new possibilities for vehicles and architectures that otherwise would not be developed' and creates an opportunity for a "modular" approach that allows brands to pick and choose items from base component sets to create unique offerings.

"We have within the VW Group two basic architectures: MLB for cars that have a longitudinal powertrain [Audi A4 to A8' Bentley GT and Continental] and MQB for those that have a transverse powertrain [VW Polo to Passat]'" says Michael Dick' member of Audi's Board of Management responsible for Technical Development. Audi is responsible for the MLB' VW for the MQB' and both are overlaid by a so-called "module organization" that breaks the car into four major component sets-powertrain' suspension' electrical/electronics' and the rest of the vehicle-comprising a reported 24 unique modules that can be mixed and matched to create vehicles of different shapes and sizes. Each is guided by a small management group and organizationally equal. Says Dr. Ulrich Hackenberg' a VW Group board member responsible for Development: "The planning process is very intensive with lots of friction created by the different opinions and needs' and promotes the negotiation necessary to give each concept all of the ‘goodies' each brand needs." Hackenberg and Dick both describe this "high-frequency" process as "fast moving" and "extremely disciplined" because the negotiations create product plans that allow the automaker to respond with very little investment in either production or engineering capacity as the market splits into smaller sub-segments.

Take' for example' powertrain creation. Rather than develop unique powertrains for each brand' a centralized organization that encompasses representatives from each brand creates a menu of engines and transmissions from which each can draw. To this they can add further modules (e.g. turbocharging and/or supercharging) to create unique variants for their brand. Each variant' however' must adhere to the geometry of the parts on which it builds and the vehicles into which it is placed in order to hold to the central dictate that each component and module is designed just once. As it plays out across the company' it will pay dividends in that each engine can share its basic piston' connecting rod' valve layout' or head design' and transmissions will use common components to create either longitudinal or transverse units. This allows the VW Group to spread its costs across all of its brands (Audi' Bentley' Lamborghini' Seat' Skoda' and VW) while increasing technology content. It also helps reduce the time it takes to bring new vehicles to market.

"If the mechanical parts come out of the modular design system' we have 24 months from the time we make a design decision"-defined as the point at which the hard points are settled' but six months before the design is frozen-"until production'" says Hackenberg. And insiders say more pieces will be commonized-that is' drawn from a basic design that can be upgraded in terms of materials' section size' and reinforcements for use in different vehicles-in order to reduce development cost and time. In addition to these changes' the VW Group has moved to a single basic production architecture. "In the past we had different platforms wherein it wasn't possible to build a car based on Platform 1 in the factory made for Platform 2 or 3'" says Hackenberg. However' by utilizing the same basic build sequence and production flow' VW is able to divide its vehicles in terms of size and content' and build a wide variety of vehicles in the same factory. Because the number of options defines the overall length of the assembly line and the number of modules in it' "It wouldn't make sense to build an assembly line for the Phaeton or Passat and add the Polo on the same line'" admits Hackenberg. However' it does make sense to match the Golf' Jetta' and Passat in one factory' the Polo and the Golf in another' and sprinkle other MQB variants around as needed. "There is a tremendous cost savings to doing it this way'" he says. All told' VW expects to reduce development costs a total of 40% once its modularity strategy is fully implemented.