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AssigneeRobert Bosch GmbH
InventorsAndreas Blumenstock, Helmut Denz, Werner Mezger, Ernst Wild
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The invention is directed to a method of checking a tank-venting apparatus for a motor vehicle equipped with a fuel tank and an internal combustion engine having an intake pipe. The apparatus includes an adsorption filter having a venting end and an intake end, a supply line connecting the intake end to the tank and a connecting line interconnecting the intake pipe of the engine and the intake end of the adsorption filter. A tank-venting valve is mounted in the connecting line between the intake pipe and the intake end of the adsorption filter and a drive unit for actuating the tank-venting valve. The method includes the steps of: changing the open state of the tank-venting valve when a pregiven operating state range of the engine is present; detecting the difference pressure between the pressure at the intake end of the adsorption filter and the ambient pressure; checking if the difference pressure or the end value of the difference pressure change lies in a predetermined range after the open state of the tank-venting valve is changed; and, issuing a fault announcement if neither the difference pressure, the time constant of the difference pressure change nor the end value of the difference pressure change lies in said predetermined range. The invention utilizes the realization that the difference pressure is based on the gas flow into and out of the adsorption filter. The difference pressure drops when the outflow is clogged or when there is a leak. On the other hand, the difference pressure increases when the inflow is clogged. In this way, the operability of the tank-venting apparatus can be checked in a simple manner.
A method of checking a tank-venting apparatus for a motor vehicle equipped with a fuel tank and an internal combustion engine having an intake pipe, the apparatus including an adsorption filter having a venting end and an intake end, a supply line connecting the intake end to the tank, a connecting line interconnecting the intake pipe of the engine and the intake end of the adsorption filter, a tank-venting valve mounted in the connecting line between the intake pipe and the intake end of the adsorption filter and a drive unit for actuating the tank-venting valve, the method comprising the steps of:
In a motor vehicle which includes a fuel tank and an internal combustion engine having an intake pipe and a tank-venting apparatus, the tank-venting apparatus including an adsorption filter having an intake end and a venting end, a supply line interconnecting the intake end of the adsorption filter and the fuel tank, a connecting line interconnecting the intake end of the adsorption filter and the intake pipe and a tank-venting valve mounted in the connecting line between the intake end of the adsorption filter and the intake pipe, and a drive unit for actuating the tank-venting valve, an arrangement for checking the tank-venting apparatus, the arrangement comprising:
Dependencies are inferred from the claim text.