Reducing the complexity and weight of wiring harnesses is a key advantage of using zonal architecture in electric vehicles, but it is not the only benefit. Zonal architecture can also support software-defined vehicle (SDV) features, optimizing electric vehicle performance and enabling improved distribution architecture to enhance operational efficiency.
This FAQ first reviews the existing domain architectures in automobiles, then introduces alternative implementations of zonal architecture, exploring how these architectures can improve performance. Today’s domain architecture organizes electronic control units (ECUs) according to their functionality. Examples of domain functions include infotainment, body control, telematics, advanced driver-assistance systems (ADAS), and passive safety features.
ECUs within a domain perform specific functions via optimized network connections and can also communicate with other domains, often through a gateway (Figure 1). Optional domain controllers may include multiple ECUs, reducing costs and improving performance.
In zonal architecture, ECUs are categorized based on their location within the vehicle. Controllers are positioned closer to the ECUs, reducing the amount of wiring required, simplifying the harness, and reducing the harness weight by up to 50%, thereby lightening the vehicle. Zonal architecture can improve data and power distribution.
The development of Time-Sensitive Networking (TSN) in automotive Ethernet is one technology enabling zonal architecture. It allows for efficient communication between ECUs that were originally in the same domain but are now distributed across different zones.
Zonal architecture also supports the implementation of SDV features. SDVs can add new features without the need to add new hardware (ECUs); instead, new features can be downloaded via wireless updates to a powerful central vehicle controller. This allows for continuous integration and continuous deployment (CI/CD) of nearly real-time new vehicle features. (For a discussion of SDVs and EVs, see the Software-Defined Vehicle FAQ.) The number of zonal controllers may vary depending on the vehicle's requirements and complexity (Figure 2).
Figure 2. As vehicle complexity increases (from left to right), the number of zones also increases. (Image: Aptiv)
Zonal architecture also supports the use of intelligent power distribution boxes, which deliver power to individual ECUs and loads while connecting to the central vehicle controller. These smart distribution boxes use semiconductor solutions to replace relays and fuses for power control and management. Smart fuses are an example of the power distribution advantages of zonal architecture in electric vehicles.
Smart fuses use power MOSFETs to quickly shut off power in the event of an overload. They react faster than traditional fusible links, providing enhanced protection. Smart fuses can improve battery energy usage in electric vehicles, which is especially useful when the battery charge is low. They can shut down non-essential functions, increasing range and extending battery life. For example, the HVAC system can be turned off for a short period that does not affect passenger comfort but is long enough to significantly improve driving range.
Another example is turning off the HVAC compressor when battery load demands peak, such as during a sharp turn when power steering is engaged. Reducing peak discharge rates can significantly extend battery life. Smart fuses can also detect an increase in impedance in the circuit they are connected to, alerting the central controller of the need for maintenance before a system failure occurs.
When using traditional fuses, the distribution lines are typically designed to be 30% larger than the basic power requirements to handle the peak load needed to blow the fuse. With smart fuses in a zonal architecture, the wire size can be adjusted according to the load requirements, typically reducing the wire gauge by one size, thus reducing the size and weight of the distribution harness.
The article is reproduced from the WeChat public account: qicheyanjiuyuanauto