Audi A4 - Car Body Development Facelift

A wide-ranging project
Bertrandt was asked to provide a whole package of measures for the A4. Both the saloon and the estate version, the Avant, were to be given a product upgrade that went far beyond the usual facelift. This included a whole range of new approaches: changing the complete front end to accommodate the singleframe design, introducing new gaps and tornado lines on the sides as well as implementing pedestrian protection measures on the existing front end. The rear was modified to include the new two-piece design for the lights, with the result that the boot lid and rear hatch for the saloon and Avant needed to be redesigned. The change in the shut line meant that the luggage compartment lining also had to be modified. By including further areas of responsibility, such as project management, tolerance analyses, FMEA, functional design and testing, the project required a high level of independent development work. As the project proceeded, the large number of changes required and the extensive package of measures meant Audi A4 More than Just a New Face that the vehicle had to be treated as a completely new development.

Project management ensures smooth processes
Due to the customer requirements and the complexity of the project, Bertrandt set up a project management (PM) team consisting of a steering group, a project leader and several persons responsible for individual parts of the package. The team’s main tasks at the start of the project included precise week-byweek planning of the processes and the provision of PM tools from kick-off to the lifetime of the components. Within the framework of the overall project, their job was to monitor the specified planning and to initiate control measures if required. On the basis of this coordinated and targeted cooperation, the engineers.

Functional body design

A typical example of how the different divisions worked together was the coordination between the simulation and design teams. Bertrandt engineers worked on projects ranging from the functional design of the closures right up to the simulation of the entire body in terms of function and crash behaviour. Bertrandt provided for the requirements to be independently checked and for modification suggestions to be prepared, which were then submitted to the customer.

Virtual and real-life testing of pedestrian protection
This close cooperation was especially necessary in the area of pedestrian protection. The challenge lay in constructing sections of an already existing front-end structure in order to be more pedestrian-friendly. One of the measures was to modify the boundary surface of the bonnet, as deformed by the impact of a pedestrian’s head. The part was made collision-free using DMU cycles in the same way as a real component. In addition to the virtual proportion of the process chain “Pedestrian Protection”, some of the final testing of the real hardware was also carried out at Bertrandt in Ingolstadt.

Design in every corner – premium all round
Inter-divisional cooperation was also necessary in the designing process. For example, when the CATIA models of the rear hatch were completed, it became apparent that the frame areas did not meet the optical requirements. With the aid of the surfacing team, the surfaces were modified in coordination with the designers, with the result that the design now fully meets the expectations of a premium vehicle.

1 Front-end structure of the Audi A4 with the Head-Form- Impactor. 2 Boundary surface of a bonnet deformed by a Head-Form- Impactor: simulation of penetration as basis for package adjustments.

Supporting activities improve development quality
The success of the development also depended on a wide range of supporting activities. These included preparing newly designed or modified FMEAs for the relevant assemblies, tolerance chain analyses for determining clearances and adjustment ranges, functional dimension catalogues for these tolerances, documentation for the release of components and, as a central part of the development, carrying out the simultaneous engineering (SE) meetings with Audi employees from the corresponding divisions at the Bertrandt office. A new aspect was the systematic implementation of design-accompanying DMUs with collision reports on every component release. As a result, the series launch was equally trouble-free with regard to component collisions.

Parts logistics and safety coordination
In the A4 project, Bertrandt was for the first time asked to work on the car’s safety aspects. Bertrandt Ingolstadt and Bertrandt Projektgesellschaft (BPG) worked hand in hand. The concrete projects included monitoring the parts logistics and coordinating the crash tests – experience that can now be used for further customer projects.

Summary and conclusion

Following its successful work on the Audi A3, the development of the product upgrade for the A4 saloon and the Avant was for Bertrandt Ingolstadt a further major project in which efficient cooperation could be successfully continued. The result can now be seen on the road – expressive and full of character: the new face of the Audi A4.