| 摘要 |
<p>PURPOSE:To provide an exhaust gas purifying device which has a simple and inexpensive structure and which can adsorb HC to an adsorbent and separate the same for purification. CONSTITUTION:A catalyst device 3 provided in the exhaust pipe of an engine 1 has an upstream large-diameter part which is sectioned into a main exhaust passage 21 and a bypass passage 4 in which an adsorbent 5 is provided, and a downstream opening in which a change-over valve 6 is provided. A shut-off valve 8 which can be selectively set in a completely closed condition or in a check-valve condition in which the valve 8 is opened only when the exhaust manifold pressure is low, is located in a circulating pipe 7 communicating between the bypass passage 4 downstream of the adsorbent 5 and the exhaust manifold of the engine 1 just after an exhaust valve. In the case of trapping of an electronic control device 9 actuates the change-over valve 6 so as to close the exhaust pipe 2 but open the bypass passage 4. In the case of separating and purifying HC, the exhaust passage 2 is opened, but the bypass passage 4 is closed. The shut-off valve 8 is opened by a negative pressure in the exhaust manifold 1, and accordingly, HC is separated from the adsorbent and is circulated into the exhaust manifold 11.</p> |
