| 摘要 |
<p>An exhaust control valve (3) is connected to an exhaust manifold (2) of an internal combustion engine of an automobile. In the exhaust control valve, either of two valve discs (9,10) is opened, and an exhaust gas flows in one of exhaust pipes (15,16). A first catalytic converter (17) is provided on one of the exhaust pipes (16), and a second catalytic converter (19) is provided to a collecting pipe (18) to which the two exhaust pipes are merged. A temperature sensor (31) detects temperature of the second catalytic converter to operate a control circuit (27). When the temperature sensor detects that the second catalytic converter is below 500 DEG C, an actuator (20) is operated by the control circuit via a solenoid valve (22) and a negative pressure tank (24) to open one of the valve discs to flow the exhaust gas into the exhaust pipe having the first catalytic converter to purify hazardous substance in the low temperature exhaust gas. <IMAGE></p> |
