| 摘要 |
<p>PROBLEM TO BE SOLVED: To promote the regeneration of a DPF provided in an exhaust system of an internal combustion engine. SOLUTION: A three-way valve 97 is provided in the course of a combustion gas discharge path 36 for returning the combustion gas of a combustion heater 17 to a connecting pipe 25 on the upstream side of an intake pipe 23, a different three-way valve 97' is provided in the course of a branch pipe 95 connecting the three way valve 97 to the downstream side connecting pipe 27, and the three-way valve 97' and the upstream side of an exhaust emission control device 50 in an exhaust pipe 42 are connected by a bypass pipe 48 bypassing an engine body 3. An oxidation catalyst 52 is provided on the upstream side of the exhaust emission control device 50, while a DPF 53 is provided on the downstream side of the purifier. When the temperature of combustion gas does not reach the temperature necessary to regenerate the DPF, the combustion heater 17 is operated to allow the combustion gas to flow into the bypass pipe 48 through the three-way valves 97, 97'.</p> |
