Abstract: A fuel filter having a filter element for filtering out particles and water from a fuel flowing through the fuel filter and having a water drainage unit for conveying filtered-out water out of the fuel filter, in which the water drainage unit is embodied as a stand-alone unit that may be separated from the filter element as needed. Also a semipermeable membrane that is permeable to water rests flat on a support. Alternatively or in addition, the water drainage unit is provided with a porous element for the evaporation of the separated water. In another embodiment two water-permeable semipermeable and hydrophilic membranes are provided. Finally, the filter element is embodied essentially in the form of a hollow cylinder in which at least part of the water drainage unit may be situated on the interior of the hollow cylinder.

Abstract: The invention relates to a fuel filter (1) with a filter element (2) for separating particles and water out of a fuel flow flowing through the fuel filter (1), a collecting space (6) for collecting the separated water (7), and a dewatering device (3) for discharging the separated water (7) out of the fuel filter (1). Here, it is essential to the invention that the dewatering device (3) has a hydrocarbon adsorber (9) for adsorbing hydrocarbon components which are entrained in the separated water (7).

Abstract: A method for operation of an internal combustion engine, comprising an exhaust treatment device in the exhaust system thereof, with application of a reagent under given operating conditions of the internal combustion engine and/or the exhaust treatment device and a device for carrying out the method are disclosed, wherein a correction parameter is determined for a reagent signal, describing the amount of reagent to be introduced into the exhaust system and the correction parameter is determined by means of a comparison of a measure of the actual amount of the reagent in the exhaust system, which should be introduced based on a measure of a pre-determined set amount and the measure of the set amount. The above method permits a particularly exact maintenance of the amount of reagent introduced into the exhaust system in accordance with the pre-determined measure for the set amount.

Abstract: A method for directly evacuating water that has been separated from the filtered fuel in a fuel filter and has settled in a water collection chamber (4) of the fuel filter to an evacuation area that lies above the water level, by opening a shut-off valve (7), which leads to the exterior of the fuel filter and is connected in a water-conductive manner to the water collection chamber (4). Said evacuation takes place under a pressure that is higher in the water collection chamber (4) in relation to the evacuation area, whereby said pressure differential is created either by the operating pressure within the fuel filter during operation, or by a negative pressure that is applied externally. The method permits the simple evacuation of water form the interior of a fuel filter by a method that is not based on gravity. The inventive method can be implemented in a particularly advantageous manner, using specially configured fuel filters.