| 摘要 |
<p>PURPOSE: To rapidly warm up a catalyst in a warm state by providing two exhaust ports along the axial air cylinder, connecting a catalyst device to both ports by way of change-over valves and exchanging the valves in response to the temperature of the catalytic device. CONSTITUTION: In an air cylinder 1 of a two-stroke engine, two exhaust ports 4, 5 are axially provided. The port 4 is connected to a catalytic device 16 by way of a tube 7, and the port 5 is connected to the catalytic device 16 by way of a tube 8, which are connected downstream side of the catalytic device 16 by way of a tube 10. A shutter 12 is provided at the bifurcation point 21. A temperature sensor 27 is installed to catalyst 9 so that when the catalytic temperature is low, low-temperature exhaust gas from the port 5 is prevented from flowing into the catalytic device 16 by closing the shutter 12. Thereby, rapid warming up of catalyst can be performed.</p> |
