System Architecture Safety Design Patterns

L6 20 System Architecture Safety Design Patterns

Where does the Name E-gas Come from?

The E-gas design pattern originally comes from an acceleration drive-by-wire system. Originally the gas pedal on a car had a direct mechanical connection to the throttle valve on an engine. The throttle valve regulates how much air enters into the engine.

In modern cars, the accelerator pedal is an electronic sensor. When you push down on the accelerator pedal, software interprets how much you want to accelerate. And then the software opens or closes the throttle valve. The E-gas software pattern was developed to monitor faults in drive-by-wire acceleration systems. In the case of a gasoline engine system failure, the level 2 or level 3 monitoring functions could lower the throttle.

Software Partitioning and Safety Monitoring

Safety monitoring and software partitions are software mechanisms commonly solved with design patterns.

For safety monitoring, there are specific patterns like the E-GAS concept which was explained. In the case of software partitions, one pattern is to use a hardware feature called MPU along with dual data storage.