Today`s E/E Architectures
Last updated
Last updated
Currently, in most modern vehicles, Electrical/Electronic (E/E) architectures feature a very large number of highly specialized ECUs and extremely complex wiring harnesses.
For example, compact cars today may contain up to 70 ECUs, while high-end cars can include up to 150 ECUs. Similarly, the wiring harness in high-end cars can span up to 5 kilometers, weighing as much as 30 kilograms.
The high number of ECUs and the complexity of the wiring harness present several challenges:
Engineering Complexity: Managing such intricate systems becomes increasingly difficult, particularly when coordinating multiple stakeholders, teams, and suppliers.
Testing Difficulties: The sheer number of components and connections makes comprehensive testing a significant challenge.
Weight: The weight of the wiring harness contributes to overall vehicle inefficiency.
Manufacturing Complexity: Building and testing vehicles with such elaborate architectures adds layers of difficulty to the production process.
Maintenance and Repair: Troubleshooting and fixing issues in these tightly coupled systems becomes progressively more complicated.
Modern vehicles feature dozens of ECUs exchanging thousands of messages, typically via the CAN protocol. For example:
Engine Control and Diagnostics: The engine control unit shares engine speed data with the transmission ECU to optimize gear shifting and with the dashboard for display.
ASIL Examples: Anti-lock braking systems use data from wheel speed sensors.
QM Examples: Climate control sensors collect cabin data and share it with the climate control ECU.
In a typical vehicle, there can be between 250 and 2,500 different CAN message types, with 500 to 5,000 messages exchanged per second when the car is operational.
The CAN bus system creates an inherently tightly coupled system architecture, which introduces several technical limitations:
Direct Message Identification: Hard-coded message IDs create direct dependencies between senders and receivers.
Fixed Network Topology: A shared bus structure requires reconfiguration for changes, reinforcing tight coupling.
Dependency on Timing and Bandwidth: Prioritized message arbitration limits flexibility and creates potential bottlenecks.
Limited Scalability: Low bandwidth and static design hinder the addition of new ECUs or features.
Lack of Modular Abstraction: The absence of dynamic addressing or abstraction layers impedes flexibility and future upgrades.
The tight coupling imposed by CAN and similar architectures on a technical level has severe consequences on the organizational level. The increased cost and extended delivery times for new vehicle features or entire vehicle generations result from the additional overhead required to align multiple teams and organizations. These challenges make innovation slower and more expensive, highlighting the need for a shift toward more modular and scalable architectures.
