| 摘要 |
<p>PURPOSE:To improve the catalytic efficiency by selecting catalysts in each case when the exhaust gas temperature is high or low, and using the catalyst suitable under each condition. CONSTITUTION:When a control part 13 detects that the temperature of the exhaust gas which passes through an exhaust pipe 3 is below a prescribed temperature, from the information of a temperature sensor 11, a signal is sent into a driving part 12. The driving part 12 shifts a passage changing plate according to this signal, and allows the exhaust gas which passes in the exhaust pipe 3, to flow towards an exhaust pipe 4. In the exhaust pipe 4, a honeycomb type filter carrying an oxidation catalyst for low temperature is installed as a filter 8, and purification is carried out efficiently. Further, when the temperature of the exhaust gas which flows in the exhaust pipe 3 becomes over a prescribed value, the control part 13 detects this state from the temperature sensor 11, and sends out a signal into the driving part 12, and the exhaust gas is allowed to flow from the exhaust pipe 3 to the exhaust pipe 5. In the exhaust pipe 5, a foam type filter carrying an oxidation catalyst for high temperature is installed as a filter 9, and the purifying faculty for the nitrogen oxides can be improved.</p> |
