Decentral Electrics

One of the motivations for LINbus, both in general and in this case, is low-cost cabling reduction: To reduce the amount and length of cables throughout the vehicle. This has other benefits including simpler, smaller wiring looms that are easier to fit and to make.

And to maintain! I wouldn’t consider it if I didn’t think it’d make life easier. 🙂

Production cars however, largely fail to realize the full potential of cabling reduction because they still have centralised electrics, often with a fuse panel in one part of the car for all the lights, motors, heaters, etc. etc. Which of course means that those devices are all wired back to the one location

The MkV Golf has 3 fuse panels with the one at the end of the dash carrying 44 fuses. Keep in mind that each fuse needs 2 wires. One coming from the supply, via e.g. a switch or relay and the other going to the powered device. Are you getting the picture?

Keeping with the philosophy of keeping management and knowledge of devices close to the device; this implementation will have any necessary fuses located on the LINbus node that owns the respective devices. Although outputs are current-limited by driver transistors, a fuse protects against problems resulting from unimagined scenarios. Three fused power distribution boxes will isolate legs of the power distribution system if there’s a minor catastrophe (e.g. an accident) that shorts power to chassis.

Current Supply Diagrams

Current flow and distribution boxes

Physical nodes may incorporate more than one functional node. The balance has to be struck between lengths of cable between nodes and their respective devices and the costs of a separate node enclosure and internal circuitry.

Each node can detect a circuit failure. Any fault and its location are indicated to the driver almost immediately. Additional data could be provided to advise fuse type. The slave node which owns the fuse should know the type and can provide that information to the master node when it registers in the cluster.

Fuses for devices must be accessible for replacement. That means mounting the nodes in such a way and location that the fuses can be replaced quickly without special tools, and without having to dismantle anything.

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