Testing apparatus for fuel vapor treating device

摘要

A fuel vapor treating device that collects fuel vapor produced in a fuel tank and treats the vapor without releasing it into the atmosphere. The treating device is provided with a canister that collects the fuel vapor through a vapor line. A vapor control valve provided in the canister adjusts the flow of fuel vapor directed toward the canister from the tank. A purge line connects the canister to an air intake passage of an engine. The fuel collected in the canister is purged into the air intake passage through the purge line. A purge control valve provided in the purge line adjusts the flow rate of the fuel flowing through the purge line. A three-way valve selectively switches the section which the pressure sensor is connected to between the tank side and the canister side. An electronic control unit (ECU) controls the purge control valve and the three-way valve. The ECU performs testing of the sealing of the tank side and the canister side based on the tank pressure and the canister pressure which are detected by the pressure sensor. The ECU controls the three-way valve to selectively detect the pressure in the canister side before the engine is started and selectively detect the pressure in the tank side immediately after the engine is started. The ECU determines that the three-way valve is functioning normally when the difference between the detected pressures is equal to or greater than a predetermined value.