Automotive In-Vehicle Communication Network is an electronic vehicle area network that interconnects components inside a vehicle (e.g. car automobiles, truck, ship, or aircraft). Today’s vehicles contain hundreds of circuits, sensors, and many other electrical components. Communication is needed among the many circuits and functions of the vehicle. If all possible combinations of switches, sensors, motors, and other electrical devices in fully featured vehicles are accumulated, the resulting number of connections and dedicated wiring is enormous. Networking provides a more efficient method for today’s complex in-vehicle communications.

In-vehicle networking, also known as multiplexing, is a method for transferring data among distributed electronic modules via a serial data bus. Without serial networking, inter-module communication requires dedicated point-to-point wiring resulting in bulky, expensive, complex, and difficult to install wiring harnesses. Applying a serial data bus reduces the number of wires by combining the signals on a single wire through time division multiplexing. Information is sent to individual control modules that control each function, such as anti-lock braking, turn signals, and dashboard displays.

Benifits of In-Vehicle Networking

  • Reduced size of the wiring harness improves the system cost, weight, reliability, serviceability, installation, Immunity from external noise, Ability to operate in harsh environments, Overall robustness.
  • Common sensor data, such as vehicle speed, engine temperature, etc. are available on the network, so data can be shared, thus eliminating the need for redundant sensors.
  • Networking allows greater vehicle content flexibility because functions can be added through software changes.

In-Vehicle Networking Communication Bus Protocols

There are several in-vehicle communication network types and protocols used in vehicles by various manufactures. Here is a list of popular in-vehicle network protocols.

  • CAN – (Controller Area Network) an inexpensive low-speed serial bus for interconnecting automotive components
  • VAN – (Vehicle Area Network)
  • FlexRay – a general purpose high-speed protocol with safety-critical features
  • LIN – (Local Interconnect Network) a very low cost in-vehicle sub-network
  • J1939 and ISO 11783 – an adaptation of CAN for agricultural and commercial vehicles
  • MOST – (Media Oriented Systems Transport) a high-speed multimedia interface
  • D2B – (Domestic Digital Bus) a high-speed multimedia interface
  • Keyword Protocol 2000 (KWP2000) – a protocol for automotive diagnostic devices (runs either on a serial line or over CAN)
  • DC-BUS – Automotive power-line communication multiplexed network
  • IDB-1394
  • SMARTwireX
  • J1850
  • ISO-9141-I/-II
  • J1708 and J1587
  • SPI – (Serial Peripheral Interface)
  • IIC (or I2C)