The limits of a close hardware-software link
Yet, this ECU proliferation is not just uneconomical. It also stands in the way of innovation. Future cars (and some already on the road!) will have completely new capabilities such as automation, a high level of connectivity, a subsequent great need for cyber security, much more safety and comfort, and an electrified drivetrain which also poses new requirements to connectivity, for instance. Connectivity is also of the essence for car sharing. The old heterogeneous vehicle E/E architecture (electronic and electric) is not ready for this. Its mix of embedded systems coming from diverse sources is neither particularly permeable for a smooth data exchange nor is easily updateable – if at all. There is also no solution to adding new functions after vehicle production because there is no host to new software without yet another ECU. Cyber security is also a challenge with a heterogeneous network of ECUs. So, what to do? Well, it is time to clear up and re-structure the E/E architecture, and that is exactly what is happening now (FIG. 3). The current heterogeneous ECU network is being replaced by an architecture with a few High Performance Computers providing the computing power and the memory for the functions of a certain vehicle domain (such as powertrain, interior, body etc.).
The number of these in-vehicle servers will depend on the OEM approach to the server-based architecture and obviously on the model and take rate of the car. However, a count of three in-vehicle servers can be heard in the industry as an initial rule of thumb.