Abstract: A reducing agent tank for receiving and storing a reducing agent solution, with a filler pipe and a fill level sensor for determining the level of the aqueous reducing agent solution in the reducing agent tank. In order to create a reducing agent tank for receiving and storing an aqueous reducing agent solution that allows storage of the liquid pollutant-reducing medium and simultaneously enables reliable detection of incorrect filling of the tank, a first electrode and a second electrode are arranged in the filler pipe such that a liquid flowing into the reducing agent tank flows over the first electrode and a second electrode, the first electrode and the second electrode coming into direct contact with the inflowing liquid.

Abstract: A device for ascertaining a measure of a calorific value of a gas, having a membrane arranged between a first and a second electrode a controllable voltage/current source for generating a control voltage/current between the first and second electrode, and an analyzing device for ascertaining the measure of the calorific value of the gas. By applying the control voltage/current to the first and second electrode, oxygen is transported from an oxygen-containing reference gas into the gas through the membrane and is combusted with combustible components of the gas. The analyzing device ascertains the measure of the calorific value of the gas dependent on the generated control voltage/current a temperature of the membrane, or dependent on an impedance of the membrane.

Abstract: A reducing agent tank for receiving and storing a reducing agent solution, with a filler pipe and a fill level sensor for determining the level of the aqueous reducing agent solution in the reducing agent tank. In order to create a reducing agent tank for receiving and storing an aqueous reducing agent solution that allows storage of the liquid pollutant-reducing medium and simultaneously enables reliable detection of incorrect filling of the tank, a first electrode and a second electrode are arranged in the filler pipe such that a liquid flowing into the reducing agent tank flows over the first electrode and a second electrode, the first electrode and the second electrode coming into direct contact with the inflowing liquid.

Abstract: A device for ascertaining a measure of a calorific value of a gas, having a membrane arranged between a first and a second electrode a controllable voltage/current source for generating a control voltage/current between the first and second electrode, and an analyzing device for ascertaining the measure of the calorific value of the gas. By applying the control voltage/current to the first and second electrode, oxygen is transported from an oxygen-containing reference gas into the gas through the membrane and is combusted with combustible components of the gas. The analyzing device ascertains the measure of the calorific value of the gas dependent on the generated control voltage/current a temperature of the membrane, or dependent on an impedance of the membrane.