BMW Emergency Vehicles

Quickly and Safely on the Road

Development Services for Emergency Vehicles
In the spring of 2003, BMW commissioned the Bertrandt site in Munich to develop emergency vehicles on the basis of the 3 Series saloon and estate models. This was the first time that BMW had assigned all the electrical, electronics and design tasks to an external partner. The start of vehicle production was planned for September 2005.


Integrating special equipment
The work involved in integrating the special equipment ranged from developing a variety of electrical and electronic components and wiring loom modules, adapting the vehicle’s electrical system and designing the necessary brackets and retainers inside and outside the vehicle through to developing prototype components and incorporating them into prototype vehicles. The objectives of the project were to allow the equipment to be "fitted on the standard production line" and to be "removed easily and cost-effectively". In addition, special requirements had to be taken into account in the development process. For example, the special equipment in unmarked police cars must not be visible from the outside and therefore had to be integrated into the interior fittings. From the very beginning of the project, the Bertrandt development team worked closely with the relevant departments at BMW to develop the concepts. A project office was set up for the Bertrandt team in order to ensure that the project ran efficiently and that the design (CAD) and electrical development units were closely networked to allow for direct cooperation between the two teams.

In order to integrate the electrical components, such as the radio, roof signalling unit, loudspeakers, front and rear signalling units and an additional backup power supply, the standard wiring loom had to be extended. The bodywork and audio wiring loom modules were developed using the "Grivad" tool. Preparations were made for the release of the modules for volume production in close cooperation with the suppliers of the individual emergency vehicle components and the supplier of the wiring loom.

From prototype development through to small-scale production
After the detailed concept design process was completed, the prototype components for mounting the special equipment were produced. Using these parts, it was possible to test the ease of assembly on prototype vehicles on the production line. A wide range of manufacturing processes were used to produce the functional prototypes, ranging from sheet metal working and the creation of polyurethane castings through to coating the plastic components. The special fittings from the various suppliers were modified sufficiently to allow the components to be assembled without problems on the production line. After optimisation loops had been incorporated in the prototyping process, the final concepts and the "final" volume production status were determined. The next step was to verify the production status using volume production processes during the pre-production and production start-up stages.


Developing a central control unit

The control centre used to operate the special equipment was developed in parallel with the process of integrating the special fittings. The control centre comes in two different versions with either six or twelve buttons.

At the heart of the control centre is a processor card that collects information from the vehicle and coordinates it with the button positions to produce the appropriate output for the special signal unit or special equipment. The control centre had to be tested for EMC (electromagnetic compatibility) before it could be used in the vehicles.

Since September 2005, Bertrandt has been working on the pre-assembly of the electrical components and on integrating them into the hardware modules that are delivered to the production line as parts sets. The Bertrandt team and BMW are pleased that the production start-up has gone smoothly and that the feedback from the various BMW departments on the collaboration with Bertrandt was universally positive.

Background Information
The trend for leasing amongst car manufacturers is also being extended to emergency vehicles. The manufacturers have developed concepts that allow the vehicles to be converted back to their standard form after a limited period of use. Once the vehicles have been returned to "civilian" status, they can be sold on the normal market. Engineering service providers such as the Bertrandt AG have adapted to meet these new requirements and now offer a complete range of development services for the special equipment in emergency vehicles.