| 摘要 |
<p>PURPOSE:To prevent decrease of the temperature of exhaust gas as much as possible and to early heat up an exhaust gas purifying device by means of high temperature exhaust gas, by a method wherein, during cooling down of an engine, an exhaust gas introducing passage is increased in size. CONSTITUTION:During cooling down of an engine 1, a switching valve 18 is opened irrespective of an operating condition of the engine 1. First and second control valves 32 and 34 are opened, an exhaust pressure on the upper stream of a turbine 9 is introduced to a first pressure chamber 30a, and an intake air negative pressure on the downstream of a throttle valve 13 is introduced to a secnd pressure chamber 30e to open the switching valve 18. When the temperature of cooling water for an engine 1 is increased to higher than a set value, the first and second control valves 32 and 34 are brought into an OFF-state, the switching valve 18 is closed, and exhaust gas is introduced in the turbine 9 only through an exhaust gas introducing passage 16 for low speed as a velocity of flow is increased. During high speed operation, the switching valve 18 is opened.</p> |
