| 摘要 |
In a method for testing the tightness of a fuel tank in a motor vehicle, a container that absorbs fuel vapors and is connected by a vent line with a fuel tank and by a scavenging line with an intake manifold of the internal combustion engine of the motor vehicle is provided. The container has a vent line that is connected to the atmosphere, the line being closable by a shutoff valve. In addition, a pressure sensor that detects the system pressure in the fuel tank and a scavenging valve located in the scavenging line, which is opened to feed the fuel vapors stored in container and to develop a vacuum in the tank ventilation system, is provided. The fuel tank is kept at a specific pressure at least approximately during the entire operation of the vehicle and, after a preliminary period that corresponds at least approximately to the time interval during which compensatory processes such as condensation or outgassing of the fuel run to completion, the tightness test is performed at any point in time and in any operating state of the vehicle with the fuel tank sealed pressure-tight.
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