| 摘要 |
An engine (1) is provided with: a urea water injector (40) which is provided to an exhaust pipe (30) of the engine (1) provided to a vehicle, and which supplies urea water into the exhaust pipe (30) by way of injection; selective reduction-type catalysts (34) which are provided to the exhaust pipe (30) at a downstream side of the urea water injector (40), and which use the urea water supplied by the urea water injector (40) to reduce and purify nitrogen oxide included in exhaust gas inside the exhaust pipe (30); and a low-pressure exhaust-gas recirculation passage (45) in which exhaust gas from the exhaust pipe (30) at an upstream side of the selective reduction-type catalysts (34) is introduced and recirculated into an air inlet pipe (20) of the engine (1). In said engine (1), when an exhaust-gas recirculation valve (48) for opening and closing the low-pressure exhaust-gas recirculation passage (45) is switched from a closed state into an open state, supply of the urea water by the urea water injector (40) by way of injection is suspended. |
