Like all industries the automotive industry has its own abbreviations and acronyms, and to add to that every original equipment manufacturer(OEM) also tend to add their own flavor. So, be warned some of the explanations given in this text could have a slightly different meaning from going from one OEM to another. Lets start with defining
IVI: In-Vehicle Infotainment
The traditional and somewhat simplified definition of IVI would typically be navigation and media playback applications. Today, the story is a bit more complicated since there are more applications and use-cases that would be categorized as infotainment. Still, it is: a combination of entertainment and information services for the driver and passengers. One could view IVI as a subset – not a genuine subset though – of the applications residing on a smartphone.
ECU = Electrical Control Unit
A modern car is a highly distributed electrical-mechanical computer system. It consists of several ECUs and a large number of sensors and actuators. An ECU is basically a computer connected to the vehicle network. Examples of ECUs are Engine Control, ABS Control, and one other example is the IHU.
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IHU = Infotainment Head Unit
The infotainment head unit could be view as the smartphone of the car and usually it consists of two parts: a vehicle cpu and a main cpu. The v-cpu mainly controls the communication to the vehicle network and monitors the main cpu so that it behaves and does not end up in a none controllable state. The main cpu is where the infotainment applications are executed, and here we have a traditional operating systems running like Windows CE, Linux or Android.
The IHU controls a number of displays, in some cases these display are ECUs of their own meaning that they could have rendering capabilities. Lately though , with technology like GPU sharing displays are mostly “dumb” displays.
CSD = Center Stack Display
The center stack display is where the navigation application is rendered and where we interact with radio or other media applications. It has a UI or more correct a HMI = Human Machine Interface.
HUD = Head Up Display
This is the projection on the windshield where you could have turn-by-turn navigation graphics, speed and possibly also augmented reality.
DIM/Cluster = Drivers Information Module/Instrument Cluster.
Speedometer, engine control gauges , turn-by-turn navigation, whats playing, outside temperature, etc…
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Vehicle network buses
The large number of data signals produced by sensors are communicated using various network buses. Here is a list of some common ones. Note, that a vehicle network consists of multiple network buses.
CAN = Controller Area Network
Vehicle data bus, message based that are designed to let microcontrollers to communicate without a host computer.
Higher speed than CAN, but basically the same.
LIN = Local Interconnect Network
Simple, cheap network protocol. One example would be steering wheel buttons used to control the volume of the audio system in the car.
MOST = Media Oriented System Transport
Media communication protocol, video, audio , voice.
Ethernet is becoming more popular and will likely replace both CAN and FLEXRAY in the future, or maybe that it is just a developers wet dream , that the industry would get rid of all these different buses and have one that speaks IP.
So, this was brief introduction naming some of the hardware and software components that are relevant for an In-Vehicle-Infotainment system.