| 摘要 |
A canister contains two cartridges of activated carbon for storing fuel in gasoline powered motor vehicles. A first cartridge operates to prevent release of hydrocarbons vaporized in the fuel tank while the vehicle is not operating. The second cartridge performs two functions. First, the second cartridge traps fuel in vapor displaced during refueling. Second, the second cartridge is charged with adsorbed fuel after the engine is stopped. Vaporous fuel from the first and second cartridges is supplied to fuel the engine upon startup. An air-fuel ratio sensor and a fuel vapor sensor are achieved by comparing the transit time of sound in two chambers, one containing air and the other containing a mixture of air and fuel. After the engine is stopped a solenoid valve is closed and an electrically energized air pump draws vapor from the fuel tank through the second cartridge to charge it with fuel. Charging is terminated when the fuel vapor sensor senses that fuel has passed through the second cartridge without being adsorbed. The air-fuel ratio sensor measures the ratio of air to fuel provided to the engine during initial startup for controlling a valve to maintain a desired air-fuel ratio. A vacuum actuated spool valve reconnects one sensor enabling it to perform both the vapor sensing function and air-fuel ratio sensing function as required.
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