초록 ▼

A method is presented for diagnosing a condition in the fuel vapor purge system. The engine, the fuel tank and the carbon canister are connected in a three-way connection. The engine can be selectively isolated by a purge control valve, and the fuel tank can be selectively isolated by a fuel tank co

A method is presented for diagnosing a condition in the fuel vapor purge system. The engine, the fuel tank and the carbon canister are connected in a three-way connection. The engine can be selectively isolated by a purge control valve, and the fuel tank can be selectively isolated by a fuel tank control valve. The operation of both valves is coordinated by an electronic engine controller. By isolating the fuel tank, and comparing the actual rate of change of the internal tank pressure (from the tank pressure sensor) to the estimated rate of change (from engine operating conditions) it is possible to determine if a condition occurred, and whether it is in the tank or in the vapor purge lines.

대표청구항 ▼

1. A method for detecting a fuel tank condition in a vehicle, the method comprising:isolating the fuel tank from a fuel vapor storage device and from an engine; calculating an estimated rate of change of a fuel tank pressure based on an operating condition when the fuel tank is isolated; calculating

1. A method for detecting a fuel tank condition in a vehicle, the method comprising:isolating the fuel tank from a fuel vapor storage device and from an engine; calculating an estimated rate of change of a fuel tank pressure based on an operating condition when the fuel tank is isolated; calculating an actual rate of change of said fuel tank pressure when the fuel tank is isolated based on an information from a fuel tank pressure sensor; and indicating the fuel tank condition if said actual rate of change exceeds said estimated rate of change by a value greater than a preselected constant.