Increasing Communications Demands

In recent years, the amount of electronics introduced into automobiles has increased significantly. This trend is expected to continue as automobile manufacturers initiate further advances in safety, reliability, and comfort. The introduction of advanced control systems—combining multiple sensors, actuators, and electronic control units—is placing boundary demands on the existing Controller Area Network (CAN) communication bus.

Requirements for future in-car control applications include the combination of higher data rates, deterministic behavior, and the support of fault tolerance. For example, drive-by-wire, which replaces direct mechanical control of a vehicle with CPU-generated bus commands, demands high-speed bus systems that are fault tolerant, are deterministic, and can support distributed control systems.

Increased functionality requires more flexibility in both bandwidth and system extension. Communications availability, reliability, and data bandwidth are the keys for targeted applications in power train, chassis, and body control.

Requirements Comparison

As shown in the figure above, the FlexRay bus addresses the significant increase in requirements for in-vehicle applications. As the amount of electronics in automobiles increases, high-bandwidth, deterministic, and redundant communications are available through the FlexRay communications bus.