| 摘要 |
<p>An exhaust system for an internal combustion engine, comprises a down pipe (14) for connecting an exhaust manifold of the engine to a main catalytic converter and a supplementary catalytic converter arranged in a path connected in parallel with the down pipe (14). The supplementary converter has an annular passage defined between inner (18) and outer tubular (16) walls which contains a catalytic matrix (20) and communicates with the interior of the down pipe (14) at its upstream and downstream ends. A second passage (20) also communicates with the interior of the down pipe (14) at its upstream and downstream ends and an obstruction (34) obstructs the down pipe (14) between the upstream and down stream ends of both the first and the second passages. A flow control tube (32) is movable relative to the down pipe (14) between a first position in which exhaust gases can flow from the down pipe into the first annular passage and return to the down pipe downstream of the obstruction (34) after passing through the catalytic matrix (20) and a second position in which exhaust gases can flow from the down pipe (14) into the second passage (22) and return to the down pipe downstream of the obstruction without passing through the catalytic matrix (20).</p> |
