FUEL TANK VENTING SYSTEM FOR VEHICLES

摘要

A fuel tank venting system for a vehicle comprises first and second vent passages connected to the fuel tank, and a third vent passage connected to the fuel tank. The first to third vent passages each have one end thereof located in the fuel tank at an upper front location thereof, an upper rear location thereof, and an upper central location thereof, respectively. An anti-overcharging valve is arranged in the fuel tank and connected to the other end of the third vent passage. A first valve is connected to the one ends of the first and second vent passages, and a confluent vent passage extends from the first valve toward an internal combustion engine installed in the vehicle. A second valve is arranged across the confluent vent passage on one side of the first valve closer to the engine. The third vent passage has the other end thereof connected to the confluent vent passage at a location intermediate between the first valve and the second valve. The sum of set pressure of the first valve and set pressure of the second valve is set to a value higher than head pressure of the fuel tank assumed when the fuel tank is fully charged.