US 6,782,873 B2 · Method and device for the low-emission operation of a fuel cell tank system, especially of a motor vehicle

Abstract

The arrangement for operating a fuel tank system of a motor vehicle includes a pump and valve arrangement (11), an activate charcoal filter (12), a fuel supply tank (14) and a control unit (20). In addition, safety valves (31, 32) as well as a pressure switch (33) are provided. The arrangement (11) includes a de-energized bistable magnetic valve (40) which is connected via a line (41) to the control unit (20) and is driven via a control module (42). The control unit (20) is connected via lines (43, 44) to pressure and/or temperature sensors (45, 46). The pressure sensors (45, 46) supply pressure signals to the control unit (20) via the lines (43, 44). If the control module (42) comes to the result with the evaluation of the pressure/temperature data that, after parking of the vehicle, an overpressure in the fuel supply tank (14) is to be expected compared to the ambient pressure, then the bistable magnetic valve (40) is opened to conduct the excess fuel vapor in correspondence to the flow direction (47) via the active charcoal filter (12) from the supply tank (14) into the ambient of the vehicle. In the case of an underpressure, which is to be expected, the bistable magnetic valve (40) remains, in contrast, closed whereby a tightness check of the fuel tank system can take place via underpressure.

Claims10

Dependent claims

A method for operating a fuel tank system of a motor vehicle including carrying out a time-to-time tightness check of the fuel tank system, wherein an active charcoal filter is provided for taking up gaseous or vaporous fuel formed in the fuel tank system, the method comprising the steps of:

(a) detecting a parking operation of said motor vehicle;
(b) detecting at least one gas or vapor referenced physical state quantity in the interior of the fuel tank system and in the ambient of the motor vehicle;
(c) predicting a gas or vapor pressure, which is to be expected after said parking operation, in the fuel tank system while considering the difference of the physical state quantity or state quantities determined in step (b);
in the case of an overpressure, which is to be expected, including an overpressure of a gaseous or vaporous fuel in the fuel tank system compared to the corresponding pressure in the ambient of the vehicle:
(d1) conducting the gaseous or vaporous fuel via the active charcoal filter out of the fuel tank system into the ambient of the vehicle;
and, in the case of an underpressure, which is to be expected, including of the gaseous or vaporous fuel in the fuel tank system compared to the corresponding pressure in the ambient of the vehicle:
(d2) closing off the fuel tank system gas tight or vapor tight, especially for making possible a tightness check of the fuel tank system by means of the underpressure.

4 more elements

Dependencies are inferred from the claim text.

Method and device for the low-emission operation of a fuel cell tank system, especially of a motor vehicle

Life of this patent

Method and device for the low-emission operation of a fuel cell tank system, especially of a motor vehicle

Life of this patent

Abstract

Claims10