| abstract |
The DOC and LNTR are used as the upper and lower sides of the carrier by using the exhaust gas purification device having the light oil spraying means, the DOC, the lean NOx adsorption / desorption material (LNTR), the urea water spraying means, the SCR, and the measurement / control means. The nitrogen that is carried separately in front and back, DOC is located in the upper layer, lower layer or front side, LNTR is located in upper layer, lower layer or back side, and exhaust is detected while detecting the inlet temperature of SCR continuously from engine start Adsorbing oxides to the LNTR; spraying the light oil when the SCR inlet temperature reaches a temperature suitable for denitrification; burning the light oil on the DOC and heating the exhaust gas to heat the exhaust gas from the LNTR to nitrogen oxide By appropriately desorbing the substance; spraying the aqueous urea solution to bring the formed NH 3 into contact with the desorbed nitrogen oxide over the SCR; Providing cold start corresponding urea SCR system to exhibit the reducing performance of the gas temperature is sufficient nitrogen oxides even at low engine starting. |