i looked at the chart in the knowledge base but it wasnt much help but what actually happens to the build up of gasoline vapors. does the prius actually burn all of it ? while gas is being pumped, the vapors go underground for later pickup at the gas station, and when you open the gas cap there is no whoosh of some of the vapors due to the anti siphon vacuum thingy so what happens to the actual gasoline vapors? maybe all of them go underground, dont know
The bladder in the fuel tank minimise gas vapours so they don't form in the first place. The "whoosh" is the vapour that has built and is under pressure and when the gas cap is opened, it's released.
They also get adsorbed onto the graphite particles inside the vapor recovery canister. If the canister gets soaked with liquid fuel it stops working, which is why one should not top-off when fuelling.
