Patent Number: 6,804,995

Title: Fuel vapor treatment system with failure diagnosis apparatus

Abstract: A leak diagnosis control device is provided in a fuel vapor treatment system that uses one sensor to detect both the atmospheric pressure and the pressure inside the fuel vapor treatment system. The leak diagnosis control device closes off the fuel vapor treatment system between a fuel tank and a purge valve, and conducts leak analysis of the fuel vapor treatment system. An absolute pressure sensor is provided to measure the atmospheric pressure as well as the pressure inside the fuel vapor treatment system. When conditions are satisfied, the leak diagnosis control device conducts a leak diagnosis based on the atmospheric pressure and the pressure change inside the fuel vapor treatment system while the fuel vapor treatment system is closed off. The absolute pressure sensor measures the atmospheric pressure based on the open-closed status of the drain cut valve and the purge valve.

Inventors: Kawano; Akihiro (Atsugi, JP)

Assignee: Nissan Motor Co., Ltd.

International Classification: F02M 25/08 (20060101); G01M 015/00 ()

Expiration Date: 10/19/2021