Tank-venting apparatus as well as a method and arrangement for checking the tightness thereof

US5195498A · kind A · utility

Assignees

• Robert Bosch GmbH · DE
• AUDI AG · DE
• BMW AG · DE
• Dr. Ing. h.c. F. Porsche AG · DE
• VOLKSWAGEN AKTIENGESELLSCHAFT · DE

Inventors

• Johann Siebler · Fahlenbach, DE
• Stephan Pelters · Tiefenbronn, DE
• Andreas Blumenstock · Ludwigsburg, DE
• Helmut Denz · Stuttgart, DE
• Axel Michelet · Karlsfeld, DE
• Siegfried Wesinger · Fürstenfeldbruck, DE
• Kurt Almstadt · Wendeburg, DE
• Jens Drückhammer · Braunschweig, DE

Key dates

• Filing date: Mar 19, 1992
• Grant date: Mar 23, 1993
• Expiry date: Mar 19, 2012

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02M25/0809
• WIPO field: Transport
• WIPO sector: Mechanical engineering

Abstract

The 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 …