Vehicle Bus Systems

In order to make the components used in our vehicles more efficient we utilize bus structures (commonly referred to as I-Bus, K-Bus, MOST Bus, Byteflight, PT-CAN, etc.). By using bus structures in vehicles, we can accelerate communication between several different control modules. Many common vehicle systems (such as entertainment, safety, powertrain, etc.) are "stand alone" systems but also require information from other modules/systems in order to be more efficient. In order to obtain the required information the systems must also be able to simultaneously communicate without interfering with each other, which is accomplished by using various bus structures.

Example: 

The ISIS (Intelligent Safety Integration System) system on the E65 uses the Byteflight bus structure. 

Fig 1: Identifying Vehicle Bus Systems

Courtesy of BMW OF NORTH AMERICA, INC.

Depending on the equipment level of the E65, the ISIS may consist of 11 satellite components (Control Modules/Sensors) that are connected, using fiberoptic cables, to the SIM (Safety Information Module) which monitors the status of the satellite components. Since this is a safety system, components need to be activated within a fraction of a second in order to be effective, there can not be any processing delays. The SIM is connected to the ZGM (Central Gateway Module) which monitors the activity of the SIM and will direct information to the SIM and other devices in the vehicles as necessary.