| 摘要 |
<p>PURPOSE:To prevent a filter from melting and preheat particulates by heating a heater buried in the filter, and burning the particulates deposited on the filter and also forcing reverse flow of high pressure air from downstream side toward the filter. CONSTITUTION:When particulates are deposited on a filter 1, a switch 11 is turned on so as to electrify a heater 9 buried in a plug 7b for closing the hole 6 of a porous element 1a. The particulates are burned by heating the heater 9. At this time, a valve 17 is opened, while a valve 18 is closed, and exhaust gas is guided to flow from a bypass passage 16 toward a cleaned gas exhaust pipe 5 instead of its flow in a trap casing 2. And at the same time, a control valve 13 is opened, then high pressure air supplied from a pressure source 12 is guided to blow from a back flow air nozzle 14 toward the lower end surface of the filter 1, while performing adiabatic expansion. It is thus possible to cool the porous element 1a by means of reversely flowing high pressure air while improving burning efficiency by preheating high pressure air.</p> |
