汽车专业英语 教学课件 ppt 作者 廖忠诚 杨晓波 主编Chapter2 Fuel System.ppt

Vapor from the fuel tank is trapped in a charcoal canister, and stored there, until it is burned in the engine. A vapor or vent line with a check valve connects the space above the liquid fuel with the canister. This valve opens when pressure starts to rise, and lets vapor through, but not liquid. Liquid fuel closes the check valve and blocks the line, stopping liquid fuel reaching the charcoal. Some systems have a small container, called a liquid-vapor separator, above the fuel tank. It also prevents liquid fuel from reaching the charcoal. This gasoline tank has a small separator tank and a number of vents. They’re from different parts of the tank so that for as many vehicle positions as possible, at least one is always above the level of gasoline in the tank. charcoal canister炭罐 liquid-vapor separator油气分离器 2.3.4 Fuel Lines Fuel lines are usually made of metal tubing or synthetic materials. A fuel supply line carries fuel from the tank to the engine. A return line may also be provided to allow excess fuel to return to the tank. This helps prevent the formation of vapor that can occur in the fuel supply during hot conditions. The fuel filler is where fuel enters the system. The filler neck is a pipe that extends above the fuel tank. On unleaded gasoline vehicles with catalytic converters, the filler neck is designed to prevent leaded fuel being added. Its diameter is smaller than those on leaded vehicles, and a trapdoor inside the filler can only be opened by the nozzle of the unleaded gasoline spout. The filler cap seals the filler neck to keep out water and foreign objects. Water can corrode internal passages of fuel pumps and carburetors. The cap on the gasoline tank also stops gasoline vapor escaping and polluting the atmosphere. This is important for gasoline which is very volatile and vaporizes easily, especially in warmer climates. synthetic material合成材料 fuel supply line供油管路 return line回油管路 unlea