Reservoir for aqueous urea solution utilized as reduction agent for post-treatment of exhaust gases from combustion engine for catalytic reduction of nitrogen oxides, has measuring region defined with boundary surface
The reservoir (1) has a sensor device (3) for level determination and comprising an ultrasonic transmitter (4) for sending an ultrasonic pulse (5) and an ultrasonic receiver (6) for receiving of an echo (7) of the sent ultrasonic pulse. A partially convex or concave measuring region is defined with a boundary surface (8) so that the ultrasonic pulse sent by the transmitter and impinging on the boundary surface is reflected towards the receiver as the echo independent of an inclined position of the reservoir. The boundary surface is variable in its position according to the level.
