An engine exhaust gas purification device comprising control unit having successively arranged switching device (1), counter-current heat exchanger (3) and at least one exhaust gas purification component (2). The switching device (1) has a first position where a flow path (6) of the exhaust gas to the exhaust gas purification component (2) is opened and a second position where a flow path (6) of the exhaust gas to the exhaust gas purification component (2) is blocked and the exhaust gas flows along a further flow path (7) where the exhaust gas is heated and conveyed, via a flow path (20) of the exhaust gas purification component (2), and exits the exhaust gas purification unit (5) through outlet channels (4) of the counter-current heat exchanger (3). The switching device, the exhaust gas purification component, the counter-current heat exchanger and the flow paths are integrated in a compact exhaust gas treatment unit.