# US 9,038,371 B2 · 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 > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,038,371 B2 - Document ID: US9038371B2 - Status: Granted - Kind: B2 - Application number: 13/136,702 - Filed: 2011-08-08 - Published: 2012-02-09 - Granted: 2015-05-26 - Earliest claimed: 2010-08-09 - Assignees: MTU Friedrichshafen GmbH - Applicants: Nicolas Gräter - Inventors: Nicolas Gräter - Web page: https://patentgrep.com/patent/US9038371B2 ## CPC - F01N 3/208: {Control of selective catalytic reduction [SCR], e.g. by adjusting the dosing of reducing agent} - F01N 2610/14: Arrangements for the supply of substances, e.g. conduits - F01N 2610/1406: Storage means for substances, e.g. tanks or reservoirs - F01N 2610/1473: Overflow or return means for the substances, e.g. conduits or valves for the return path - F01N 2610/1493: Purging the reducing agent out of the conduits or nozzle - Y02T 10/12: Improving ICE efficiencies - F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract In a supply arrangement for supplying a solution containing a reducing agent, in particular urea, to an exhaust gas system of an internal combustion engine wherein a supply line extending from a storage tank to an injector which is connected to the exhaust gas system includes an operating tank and a dosing arrangement, a return line extends between the dosing arrangement and the storage tank and the dosing arrangement includes a directional valve for directing solution to the injector during a first operating mode in which the engine is operating and, in a second operating mode in which the engine is shut down, directing the solution back to the storage tank for emptying the operating tank. ## Claims ### Claim 1 A supply arrangement (10) for supplying a solution containing a reducing agent (R) to an exhaust gas system (20) of an internal combustion engine, comprising: a storage tank (2) having 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) further including a directional switching valve (9) operable in a first operating mode wherein, in a first position of the directional switching valve (9), the solution is supplied to the injector (1) and excess solution is returned to the operating tank (5) and the directional switching valve (9) is operable in a second operating mode wherein, in a second position of the directional switching valve (9), the solution is directed 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) in order to keep the operating tank (5) empty to prevent its freezing during shutdown of the engine. ### Claim 2 (depends on 1) The supply arrangement according to claim 1, wherein the directional switching valve (9) is arranged in the supply line (3) between the operating tank (5) and the dosing pump (8). ### Claim 3 (depends on 1) The supply arrangement according to claim 1, wherein the directional switching valve (9) is switchable so as to provide in the first operating mode for bidirectional passage of solution through the valve (9) and blockage of the return line (7). ### Claim 4 (depends on 1) The supply arrangement according to claim 1, wherein, between the storage tank (2) and the operating tank (5), a blocking device (4) is arranged in the supply line (3) which, in the second mode of operation, is shut down and for blocking solution flow between the operating tank (5) and the storage tank (2). ### Claim 5 (depends on 1) The supply arrangement according to claim 1, wherein the directional, switching valve (9) is switchable to a position wherein, in the second operating mode, the supply line is open unidirectionally in a direction toward the dosing pump (8) and is blocking in the direction toward the operating tank (5) and wherein the return line (7) is open for conducting solution back to storage tank (2). ### Claim 6 (depends on 5) The supply arrangement according to claim 5, wherein the directional switching valve (9) is switchable between the first and the second operating mode for supplying in the first operating mode the solution via the supply line (3) to the injector (1) and return excess solution to the operating tank (5) and in the second operating mode direct the solution to the return line (7). ### Claim 7 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. ### Claim 8 (depends on 7) An internal combustion engine according to claim 7, including a control unit (S) for controlling operation of an exhaust gas treatment device (30) in the exhaust system (20) and also for controlling the operation of the supply arrangement (10), wherein, in a switch-on state (E) of the exhaust gas treatment device (30), the supply system (10) is operated in the first operating mode and in a switch-off state (A) of the exhaust gas treatment device (30) the supply arrangement (10) is operated in the second operating mode. ### Claim 9 A method of supplying a solution containing a reducing agent (R) to an exhaust system (20) of an internal combustion engine (100) comprising the steps of supplying, in a first operating mode, the solution from a storage tank (2) via an operating tank (5) and a dosing arrangement (6) to an injector (1) for injection of the solution into the exhaust system, and, in a second operating mode, supplying the solution from the operating tank (5) via the dosing arrangement (6) back to the storage tank (2) so as to empty the operating tank (5) and the dosing arrangement (6) in preparation for a shutdown of the engine while any flow of solution between the storage tank (2) and the operating tank (5) is blocked and a supply pump (4) arranged in a supply line (3) between the storage tank and the operating tank (5) is shut down. ### Claim 10 (depends on 9) The method according to claim 9, wherein, in the second operating mode, any flow of the solution from the operating tank (5) to the injector (1) is blocked. ### Claim 11 (depends on 9) The method according to claim 9, wherein, in the first operating mode, solution is supplied from the storage tank (2) to the operating tank (5).