Vehicles are complex machines with a large number of parts that need to communicate with each other, and it is against this backdrop that Controller Area Networks emerged. Automotive engineer Tom Denton explains how the technology works.
Today, all modern vehicles, from traditional combustion-powered vehicles to the latest electric vehicles, are equipped with a Controller Area Network (CAN) bus. This is an electronic communication system that allows different parts of the vehicle to communicate with each other, including the engine, transmission and brakes. In a sense, it is the central nervous system of the car.
Invented by Bosch and first used in the Mercedes-Benz S-Class in 1991, CAN bus originally connected five engine control units (ECUs) to improve performance and performance by speeding up the flow of real-time data around the car. safety.
CAN bus networks can combine (or multiplex) information, reducing the number (and weight) of wires required. This is a vast improvement over previous technology, which consisted of two-way receivers and signal transmitters that couldn’t handle multiple communications simultaneously.
The CAN bus works by allowing any device on the network to create “data frames,” a standard message format, and transmit them in sequence. If multiple devices transmit at the same time, the device with the highest priority continues while the others wait.
The physical network on most cars consists of a pair of twisted wires called CAN High Speed (CAN-H) and CAN Low Speed (CAN-L).