Evaporative System Monitoring

The Task

Validate the functionality of the fuel tank evaporation system for onboard diagnostics (OBD) tests.

The Challenge

Because gasoline fuel has some hazardous characteristics, a reliable tank evaporation system is necessary to prevent a contamination of the environment. When the vehicle engine is running, the ECU has to actuate the valves of the evaporation system to draw vaporized fuel from the tank. The vaporized fuel is subsequently combusted in the engine. Furthermore, venting operation modes are available during refueling and diagnostic routines check for leakages in the tank system. For these complex interactions of the valves, it is crucial to model temperatures, pressure, and gas composition accurately.

The Solution

The evaporation system of ASM supports the calibration of these routines, because important components are physically modeled. The tank and the canister are modeled as dynamic reservoirs and calculated with the laws of mass conservation and energy equilibrium to archive realistic pressure and temperature behavior.