Apparatus and method for purifying exhaust gases for combustion engines

A method of exhaust gas purification for an internal combustion engine by at least one exhaust gas purification unit in which the exhaust gas, exiting the internal combustion engine is introduced, wherein the exhaust gas is guided through at least one exhaust gas purification component (2) and a counter-current heat exchanger (3), during cold start of the internal combustion engine, a control unit adjusts a switching device (1) such that the exhaust gas is conveyed by a direct flow path (6) to the at least one exhaust gas purification component (2), whilst by corresponding control of the internal combustion engine, a rapid heating of the exhaust gas occurs so that the at least one exhaust gas purification component (2) is rapidly heated by the engine exhaust gas and the catalytic combustion of the exhaust gas components contained therein up to operating temperature, the method comprising the steps of:

• directly conveying the exhaust gas emerging from the at least one exhaust gas purification component (2) or via a flow path (19), in outflow channels (4) of the counter-current heat exchanger (3), heats the outflow channels and from there exits the exhaust gas purification unit (5),
• after the at least one exhaust gas purification component (2) reaches the operating temperature, switching the switching device (1), via the control unit, such that the flow path (6) of the exhaust gas is blocked to the at least one exhaust gas purification component (2) so that the exhaust gas is conveyed along a further flow path (7) into the inlet channels (8) of the counter-current heat exchanger (3), where the exhaust gas is heated and from there the exhaust gas is guided, via a flow path (20) of the at least one exhaust gas purification component (2), and after passing through the exhaust gas purification component, exits the exhaust gas purification unit (5) through the outlet channels (4) of the counter-current heat exchanger (3) and thus transfers heat to the inflowing exhaust gas into the inlet channels (8), and
• maintaining a favorable operating temperature range of the at least one exhaust gas purification component (2) by exhaust gas pollutants being converted on the exhaust gas purification components (2) in exothermic reactions.