FUEL EVAPORATION GAS DISCHARGE PREVENTION SYSTEM

• Main Authors: KAMURA HITOSHI, MATSUNAGA HIDEO
• Format: Patent
• Language: English; Japanese
• Published: 07.05.2015
• Subjects: BLASTING; COMBUSTION ENGINES; HEATING; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; LIGHTING; MECHANICAL ENGINEERING; SUPPLYING COMBUSTION ENGINES IN GENERAL, WITH COMBUSTIBLEMIXTURES OR CONSTITUENTS THEREOF; WEAPONS

PROBLEM TO BE SOLVED: To detect a malfunction of a canister open/close valve.SOLUTION: When an engine is stopped and a purge valve is in an open state, a negative pressure pump is activated. When a pressure deviation P (pressure drop amount) at a moment when a first predetermined time T1 passes after a bypass valve (canister open/close valve) is controlled from an open state into a close state, is lower than a first predetermined pressure P1, the bypass valve is determined that it is in a fixedly opened condition. When the pressure deviation P is equal to or more than the first predetermined pressure P1, the bypass valve is determined that it is not in the fixedly opened condition. Thereafter, when the pressure deviation P at a moment when a second predetermined time T2 passes after the bypass valve is controlled to be opened, is equal to or lower than a second predetermined pressure P2, the bypass valve 37 is determined that it is not in a fixedly closed condition. 【課題】キャニスタ開閉弁の異常検出を可能にする。【解決手段】エンジンが停止しパージバルブが開弁状態であるときに負圧ポンプを作動しバイパス弁（キャニスタ開閉弁）を開弁から閉弁に制御してから第１の所定時間Ｔ1経過後の圧力偏差 Ｐ(圧力低下量)が第１の所定圧Ｐ1未満であれば、バイパス弁が開固着状態であると判定し、圧力偏差 Ｐが第１の所定圧Ｐ1以上であれば、バイパス弁が開固着状態でないと判定する。また、その後バイパス弁を開制御してから第２の所定時間Ｐ2経過後の圧力偏差 Ｐが第２の所定圧Ｐ2以上に低下すれば、バイパス弁３７が閉固着状態でないと判定する。【選択図】図６