Early Fuel Shut-Off

Fuel systems are critical within the automotive industry both from the perspective of design and functionality as well as liability issues. Fuel fill stops due to early shut off or spillage issues can be frustrating and possibly dangerous. Sensors at the bottom of gas pump nozzles are designed to shut off the nozzle on fuel contact indicating a filled tank. However, fuel can backfill and cause repeated early shut offs or spills, often an annoyance or even hazardous!

FLOW-3D is used here to analyze two fuel filling scenarios. In the better case (top animation), fuel is filled through the wider line while air vents through the narrow line without backfill. However, in the other case (bottom animation), fuel fills through the narrow vent line due to placement of the pump nozzle and causes a backfill resulting in a shut off/spill scenario. FLOW-3D’s TruVOF technique allows quick and accurate transient simulations of multiphase fuel flow. FLOW-3D can also model the sloshing of fuel tanks and efficient fuel indication system designs.

Comparison of designs using FLOW-3D where the top animation shows a design without back flow issues. The bottom animation has a back flow problem in the vent line.