System for controlling vaporized hydrocarbon of fuel for a gasoline engine
Evaporative emission control device of an internal combustion engine for vehicle use
Fuel evaporation gas treating device
Ventilation device for the fuel tank of a motor vehicle
Variable rate purge control for refueling vapor recovery system
On board refueling vapor recovery system
Air-fuel ratio feedback control system for internal combustion engine
Method and apparatus for setting a tank venting valve
Method of detecting abnormality in an evaporative fuel-purging system for internal combustion engines Patent #: 5085194
ApplicationNo. 854424 filed on 03/19/1992
US Classes:123/698, With addition of secondary fluid (e.g., fuel or exhaust gas)123/520Purge valve controlled by engine parameter
ExaminersPrimary: Wolfe, Willis R.
Attorney, Agent or Firm
International ClassesF02D 041/14
Foreign Application Priority Data1991-03-19 DE
AbstractThe invention is directed to a method of checking the tightness of a tank-venting apparatus for a motor vehicle having a fuel tank and an internal combustion engine including a lambda controller and an air intake pipe. The tank-venting apparatus includes an adsorption filter, a supply line interconnecting the adsorption filter and the fuel tank, a connecting line interconnecting the adsorption filter and the intake pipe and a tank-venting valve mounted in the connecting line between the adsorption filter and the intake pipe. The method includes the steps of: measuring the pressure difference between pressure in the tank and ambient pressure; when the tank-venting valve is opened, determining whether the pressure difference increases above a threshold value and whether a lean correction by the lambda controller is required; and, drawing the conclusion that the tank-venting apparatus leaks when neither a lean correction is determined nor the pressure difference exceeds the threshold value. The method is based on the recognition that, when the tank-venting valve is open, either an underpressure must build up in the tank or a lean correction must be determined by the lambda controller based on the fuel vaporizing in the tank. The method is very reliable by simultaneously carrying out these two checks.