Audi - Electronic Systems for Special Derivatives

Electronic Systems for Special Derivatives
The increase in demand for special purpose and armoured vehicles has led to manufacturers extending their product ranges. Engineering service provider Bertrandt provides support for OEMs in this market segment by developing electric and electronic systems and offering design, production and logistics services. Bertrandt was involved in the development of electronic systems for several special derivatives of the current A6 and A8 on behalf of AUDI AG.

Developing networked functions Developing networked functions

Shortly after the development process for the special derivatives of the A6 and A8 began, it emerged that a number of mutually influential standard functions were distributed across an almost equivalent number of standard electronic control units (ECU). As a result of this, networked function concepts for the different derivatives were first of all developed and then divided across a newly developed multifunction ECU and the relevant standard ECUs. The objective of this phase was to keep the adaptations to the standard ECUs to a minimum. The Bertrandt engineers converted the requirements for each ECU that emerged as a result of this stage into functional descriptions.

Development support for a multi-function ECU

In modern, networked vehicles with high levels of integration, conventional forms of intervention in vehicle functions, such as lights and indicators, represent very complex tasks. For this reason, Audi decided to develop a multi-function ECU with special functions that acts as the interface between the vehicle network and the peripherals. This integrated ECU allows the comfort CAN bus functions to be implemented or initiated via the existing standard ECUs. Bertrandt was responsible for supplier management in this process. In addition, the Bertrandt engineers also validated the software and hardware modifications to the ECU and provided specifications for the ECU at application and diagnostics level.

After this, the ECU was integrated into the vehicle network and all the functions were tested in the vehicle. It was important for Bertrandt to stay in very close touch with the relevant development departments at Audi in order to ensure that the development process ran smoothly and that the components were produced on schedule.

Function tests of networked functions

In order to ensure that the concepts that had been developed functioned correctly, manual function tests were carried out - both on the networking board that represents the entire vehicle, for example a taxi, and in prototype vehicles. Bertrandt also provided support for networking and diagnosis tests at the OEM’s site. The engineers documented the change requests that resulted from the test results and followed up the implementation of the changes.

Developing the vehicle electrical system and wiring diagram
The interfaces specific to the special vehicles, such as relays and switches in the existing vehicle wiring loom, were integrated in VOBES (Volkswagen Bordnetz Entwicklungs-System - Volkswagen vehicle electrical development system). VOBES allows the routes of the individual wires to be designed on the basis of system plans and using links to geometry information from the bodywork design and to the integration studies carried out as part of the bodywork design process. Bertrandt was responsible for developing the system wiring diagrams, which document the logical connection of the electrical systems. The project also involved specifying wire colours, cross-sections and outgoing wires from the electrical connections in the existing standard modules. After the production supplier had created the initial prototypes of the wiring loom, Bertrandt tested the wiring and connections, the lengths of the wires and the outgoing wires and redesigned them where necessary. Then additional wiring looms were developed, so that the systems specific to the special vehicles could be adapted to the existing connections. Systems from different suppliers were carefully selected to cover a wide range of the special vehicle functions. Once the manufacturer had chosen a supplier, the supplier then produced prototype-wiring looms, which were tested by Bertrandt to ensure that they were correct and provided the required functionality. After this, the wiring looms were released by the OEM. The wiring was produced and assembled on the basis of product detail assembly instructions or photo documentation. The modular wiring looms specific to each derivative were partially integrated into the standard wiring loom as a part of the production process and directly assembled on the production line. The resulting production time was relatively short, particularly when taking into account the wide variety of devices and functions specific to each special vehicle.