Here’s an interesting question: could Ethernet oust CAN, LIN, MOST, FlexRay and others to deliver a universal network for in-car control systems? The modern car can incorporate as many as 70 embedded computers, networked by a host of different networking systems, including under-bonnet control systems, overall vehicle safety systems, in-vehicle comfort systems and, increasingly, in-car entertainment and information systems.
Now automotive manufacturers are turning their attention to Ethernet as a common backbone for in-car networking, offering tantalising promise of a radical simplification of the automotive networking jungle whilst easing the introduction of the complex software modules and control applications that will characterise the next generation of vehicles.
In 2007 a BMW research group tested the Internet Protocol (IP) – an application layer of the Ethernet protocol – to network automotive controllers. The company’s engineers found that IP could well suit the real-time requirements even of safety-critical applications. And most importantly, they found that with IP networking, costs of automotive electronics could quite well be lowered considerably.
The BMW engineers tested the aptitude of IP for applications in the engine compartment (engine control unit and dynamic stability control) and in the dashboard. Their experiments were built on standard PC and embedded electronic parts. To give the system a real test, they also ran bandwidth-hungry video and other multimedia applications over the same network.
Their conclusion was that the real-time behaviour of the network far exceeded the requirements of safety-critical and other control applications, even when the multimedia applications were running at the same time. Although these studies were not part of any serial car development, the potential for Ethernet has been firmly established. BMW is adamant that talks with automotive OEMs and tier one suppliers will soon follow.
BMW is not alone in its exploration of Ethernet for in-car control systems. Papers presented at the 32nd annual conference of the IEEE Industrial Electronics Society (IECON) and at the Canadian Conference on Electrical and Computer Engineering (CCECE) in 2006 highlighted the potential for Gigabit Ethernet for on-board communication and control networks, concluding that simulations demonstrated the feasibility and success of the proposed model with mixed data traffic for both real-time and non real-time applications.
Ethernet, then, offers the tantalising possibility of replacing the many established time-critical and non time-critical vehicle networks (CAN, LIN, et al) with a single unified architecture. Certainly this is not going to happen overnight, but already we are seeing Ethernet beginning to permeate into vehicle control systems. A number of manufacturers are already incorporating Ethernet interfaces to connect in-vehicle systems to external diagnostics computers, with Ethernet switches are being employed in networking bandwidth hungry video, media and GPS systems as part of the wider in-vehicle control system.