Robert Boschgmbh

Thorsten Fritz

Lutz Reuschenbach

Eberhard Schnaibel

Andreas Blumenstock

Georg Mallebrein

Martin Streib

Helmut G Schwegler

Ulrich Kuhn

Armin Hassdenteufel

Dieter Lederer

Karl-Bernhard Lederle

Stephan Uhl

Peter Wiltsch

Michael Nicolaou

Michael Hermann

Werner Krauss

Volk R Stegmann

A method checks the operability of a tank-venting system for a motor vehicle having an internal combustion engine. The tank-venting system includes a fuel tank (), an adsorption filter () and a filter line () connecting the adsorption filter to the fuel tank. The adsorption filter () has a venting line () and a switchover/check valve () is provided for closing off the venting line (). The system includes a tank-venting valve () and a valve line () connecting the tank-venting valve to the adsorption filter. In the method, an overpressure relative to atmospheric pressure is introduced into the tank-venting system utilizing a drivable pressure source (). An operating characteristic variable of the pressure source is detected while introducing the overpressure to determine the pressure course. A conclusion is drawn as to the presence of a leak from the pressure course. The overpressure is reduced by opening the tank-venting valve () and simultaneously closing said switchover/check valve ().

Tank-venting system in a motor vehicle and method for checking the operability of the tank-venting system

In a method and a device for leak testing of a vessel, e.g., a tank venting system of a motor vehicle, a leak-tightness measurement is performed by introducing a positive pressure or partial vacuum and detecting the variation over time of a positive pressure or partial vacuum in the vessel, and a reference measurement is performed using a reference leak. A conclusion is drawn as to the presence of a leak in the vessel by comparing the results of the leak-tightness measurement and the reference measurement. To avoid faulty diagnoses, the positive pressure or partial vacuum during the leak-tightness measurement and the reference measurement is detected by using a single pressure measuring device.

Method and device for diagnosing tank leaks using a reference measuring method

A method for checking the tightness of a tank-venting system of a vehicle wherein one introduces an overpressure or underpressure compared to the atmospheric pressure via a pressure source alternately into the tank-venting system and a reference leak of a defined size connected in parallel to the tank-venting system over a pregiven time interval and wherein one detects at least one operating characteristic variable of the pressure source when introducing the pressure into the tank-venting system (tank measurement) as well as when introducing the pressure into the reference leak (reference measurement) and wherein one compares the two measurements and, when there is a deviation of the tank measurement from the reference measurement by a pregivable value, one draws a conclusion as to a leak when there is a deviation of the tank measurement from the reference measurement by a pregivable value and the method is characterized in that one draws a conclusion as to the operability of the tank-venting valve of the tank-venting system from the time-dependent trace of the operating characteristic variable for the tank measurement.

Method for conducting a leak test of a tank ventilation system of a vehicle

The invention is directed to a method for checking the operability of a tank-venting system of a vehicle. A pressure source is operatively connected to the tank-venting system and a first fill level of the tank is determined and stored at the start of a standstill of the vehicle. An overpressure relative to atmospheric pressure is introduced into the tank-venting system during the standstill of the vehicle and an operating characteristic variable of this pressure source is detected as the overpressure is introduced into the tank-venting system. A conclusion as to the presence of a leak in the tank-venting system is drawn from the operating characteristic variable. A second fill level of the tank at the end of the standstill is determined and stored. The difference of the first and second fill levels is formed and a determination is made as to whether the difference exceeds a pregiven threshold value; and, only if the threshold value is exceeded, a fault announcement is outputted.

Method for checking the operability of a tank-venting system of a vehicle

The invention is directed to a method for checking the operability of a tank-venting system of a vehicle. A pressure source introduces an overpressure into the tank-venting system with the pressure source having operating characteristic variables. A conclusion is drawn as to the ambient temperature from one of the operating characteristic variables and a determination is made as to whether the ambient temperature lies within a pregiven temperature interval. Only if the ambient temperature lies within the pregiven temperature interval is an overpressure introduced into the tank-venting system relative to atmospheric pressure. One of the operating characteristic variables of the pressure source is detected as the overpressure is introduced into the tank-venting system to obtain a pressure trace of the pressure in the tank-venting system. A conclusion as to the presence of a leak in the tank-venting system is drawn from the pressure trace.

Method of checking the operability of a tank-venting system

The invention is directed to a method for checking the operability of a tank-venting system of a motor vehicle. The tank-venting system includes a tank, an adsorption filter and a tank-venting valve. The adsorption filter has a venting line and is connected to the tank via a connecting line. The tank-venting valve is connected to the adsorption filter via a valve line. In the method, a pressure source introduces a pressure into the tank-venting system which is an overpressure compared to atmospheric pressure and the pressure source has at least one operating variable. A first time-dependent trace of the one variable is provided and this trace is characteristic for a diagnostic trace undisturbed by a tanking operation. A second time-dependent trace of the one variable is detected during standstill of the vehicle and is compared to the first time-dependent trace. An output of a fault announcement is inhibited when the second time-dependent trace deviates from the first time-dependent trace by a pregiven value.

Method for checking the operability of a tank-venting system

The invention is directed to a method for checking the operability of a tank-venting system. The tank-venting system includes a tank, an adsorption filter having a tank-venting line, a connecting line for connecting the adsorption filter to the tank, a tank-venting valve and a valve line connecting the adsorption filter to the tank-venting valve. A pressure source is provided for introducing a pressure into the tank-venting system, an operating characteristic variable of the pressure source is detected only over a pregiven time interval (.DELTA.t.sub.m) when introducing the pressure to obtain a time-dependent trace of the operating characteristic variable. The time-dependent trace is extrapolated and a conclusion is drawn as to the presence of a leak therefrom.

The invention is directed to a method and arrangement for checking the operability of a vessel. Pressure is introduced into the vessel utilizing a pressure source having operating variables which vary during operation of the pressure source. These operating variables are detected while the pressure is introduced into the vessel and a conclusion as to a presence of a leak in the vessel is drawn from the operating variables. By utilizing the operating variables, a statement as precise as possible is provided as to the presence of the leak with as little additional equipment as possible.

Growing community of inventors

Gaggenau, Germany

Thorsten Fritz