EXHAUST EMISSION CONTROL SYSTEM FOR DIESEL ENGINE

摘要

PROBLEM TO BE SOLVED: To reduce energy consumption by filter regeneration means. SOLUTION: An exhaust passage 10 of a diesel engine is branched into a first exhaust passage 14 and a second exhaust passage 16 in which a filter 22 to collect particulate matters is interposed. An opening control valve 20 is provided at a branch portion 12 and a bypass passage 28 is provided for communicating upstream and downstream of the filter 22. An electric heater 24 as filter regeneration means is provided upstream of the filter 22, while a blower 32 is interposed in the bypass passage 28. With this configuration, when the filter is not regenerated an entire amount of exhaust gas passes through the filter 22, while when the filter is regenerated the opening control valve 20 is controlled such that the first exhaust passage 14 is approximately in full-closed state and the second exhaust passage 16 is in slightly-open state so as to energize the electric heater 24. When the engine is stopped even while the filter is regenerated, exhaust gas downstream of the filter 22 is made to flow upstream through operation of the blower 32.