Abstract: An internal combustion engine having a turbocharger is provided. The engine includes a turbine of the turbocharger located in an exhaust system of the engine, an upstream side catalyst located upstream of the turbine, a catalyst bypass passage bypassing the upstream side catalyst, a catalyst bypass passage on/off valve for opening and closing the catalyst bypass passage, and a first exhaust gas recirculation passage for recirculating a part of exhaust gases from a portion between the upstream side catalyst and the turbine to an intake system of the engine. The engine, that further includes a second exhaust gas recirculation passage for recirculating a part of exhaust gases from an upstream side of the upstream side catalyst to the intake system, and a switching valve for switching between the first exhaust recirculation passage and the second exhaust recirculation passage, is provided.

Abstract: An internal combustion engine having a turbocharger is provided. The engine includes a turbine of the turbocharger located in an exhaust system of the engine, an upstream side catalyst located upstream of the turbine, a catalyst bypass passage bypassing the upstream side catalyst, a catalyst bypass passage on/off valve for opening and closing the catalyst bypass passage, and a first exhaust gas recirculation passage for recirculating a part of exhaust gases from a portion between the upstream side catalyst and the turbine to an intake system of the engine. The engine, that further includes a second exhaust gas recirculation passage for recirculating a part of exhaust gases from an upstream side of the upstream side catalyst to the intake system, and a switching valve for switching between the first exhaust recirculation passage and the second exhaust recirculation passage, is provided.

Abstract: An exhaust emission purification system for an internal combustion engine, which can appropriately recover the cleanup performance of a NOx purification device that is disposed on the downstream side of a SOx absorbent is disclosed. The exhaust emission purification system is provided with a SOx trap 13, which is provided on an upstream side of a NOx purification device 17, and a SOx desorption temperature of the SOx trap 13 being higher than that of the NOx purification device 17; a sulfur purge determination portion 21 that determines whether to execute a sulfur purge, on the basis of the SOx concentration detected by a SOx sensor 16; a sulfur purge execution portion 22 that changes the exhaust gas into a high temperature reducing atmosphere, in cases where a sulfur purge determination portion 21 determines to execute a sulfur purge of the NOx purification device 17.