| 摘要 |
<p>PURPOSE:To increase exhaust gas purification rate in a low temperature zone and reduce power consumption in an electric heater by energizing the electric heater of a first catalyst converter by shutting off a bypass pipe in the condition in which a second catalyst converter is not activated yet. CONSTITUTION:A temperature sensor on a converter 6 generates a low temperature condition signal to close a control switch 14 and energizes an electric heater 10 to heat a first catalyst converter 5 when a second catalyst converter 6 is not activated yet immediately after an engine is started. Also, a selector valve 5 keeps A position and shuts off a bypass pipe 8. As a consequence, exhaust gas from an exhaust pipe 3 is discharged into atmospheric air via a suction trapper 4 and the catalyst converters 5 and 6. During this time, HC in exhaust gas is suctioned by a suction material in the suction trapper 4. Next, when the catalyst converter 6 is activated by exhaust gas heat, the electric heater 10 is deenergized by signals of the temperature sensor to change over a selector valve 9 to B position so as to conduct into the bypass pipe 8. As a result, it is possible to reduce useless power consumption owing to deenergization in the heater 10.</p> |
