PNEUMATIC TEST METHOD FOR FUNCTIONALITY FOR TANK VENT AND PNEUMATIC TEST METHOD FOR CONTAINER

摘要

PROBLEM TO BE SOLVED: To improve a pneumatic test method for functionality for tank vent such that leakage can be diagnosed surely by eliminating the creep effect of a fuel tank. ;SOLUTION: The inventive test system comprises an adsorption filter AF coupled with a fuel tank KT and interruptible through an interruption valve AV, and a tank vent valve TEV coupled through valve piping. A specified positive or negative pressure for diagnosis is applied to the tank vent while closing the tank vent valve TEV and interruption valve AV and then the dropping gradient of the positive or negative pressure is measured in order to diagnose the airtightness. In order to eliminate the creep effect of the tank due to the positive or negative pressure, a different positive or negative pressure higher by a specified level is applied and released upon elapse of a predetermined time. The dropping gradient of positive or negative pressure is measured only when a substantially constant positive or negative pressure for diagnosis is established in the tank vent.;COPYRIGHT: (C)1997,JPO