Arrangement and method for storing a reduction agent and supplying it to an exhaust gas system of an combustion engine and an internal combustion engine including such a system

An internal combustion engine (100) having a supply arrangement (10) for supplying a solution containing a reducing agent (R) to an exhaust gas system (20) of an internal combustion engine, the supply arrangement comprising:

• a storage tank (2) with a supply line (3) connected to the storage tank (2) and including a dosing arrangement (6) with a dosing pump (8) for controlling the supply of the solution to the exhaust gas system (20),
• an operating tank (5) arranged in the supply line (3) between the storage tank (2) and the dosing arrangement (6) for an interim storage of the solution,
• an injector (1) connected to the supply line (3) downstream of the dosing arrangement (6) for injecting the solution into the exhaust gas system (20), and
• a return line (7) extending between the dosing arrangement (6) and the storage tank (2) bypassing the operating tank (5), the dosing arrangement (6) including a directional switching valve (9) operable for the delivery of the solution containing the reducing agent (R) in a first operating mode in which the solution is supplied to the injector (1), and excess solution is returned to the operating tank (5) and the directional switching valve being operable to direct in a second operating mode in which, upon shutdown of the internal combustion engine, the directional switching valve (9) is switched so as to direct the solution to the return line (7) for returning all of the solution from the operating tank (5) to the storage tank (2) to empty the operating tank (5) during engine shutdown, the exhaust gas system (20) including a catalytic converter (K) for a selective catalytic NOx reduction and the supply arrangement (10) being connected to the exhaust gas system (20) upstream of the catalytic converter.