| 摘要 |
<p>PURPOSE:To heighten the cleaning of exhaust gas with a catalyst, by by-passing the exhaust gas around the exhaust turbine of a supercharger to conduct the exhaust gas directly to the catalyst when the temperature or revolution of an engine is low. CONSTITUTION:When the temperature of an engine is low, a thermosensitive switch 21 is off. When the rotational frequency of the engine is low, a rotational frequency detection switch 22 is off. Under at least one of these conditions, a solenoid valve 15 is not put in operation, the negative pressure of a vacuum source 16 acts to a negative pressure actuator 17, a passage 9 is shut off by a valve 13 and a by-pass 12 is opened so that the exhaust gas of the engine does not act to the exhaust turbine 7b of a supercharger 7 but directly enters into a catalyst 10. For that reason, the exhaust gas is effectually cleaned although it is hard for the catalyst to cause reaction under the condition. In that case, a valve 8 at the outlet port of a supercharging turbine 7a is closed to reduce the resistance to intake.</p> |
