EXHAUST EMISSION CONTROL DEVICE OF INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To properly control NOxin exhaust gas by discharging NOxfrom an NOxstorage type catalyst by supplying fuel in mist form from a fuel supply valve and reducing this discharged NOxto NH2.

SOLUTION: A NOxselective reduction catalyst 14 is arranged in an engine exhaust passage and the NOxstorage type catalyst 12 capable of occluding NOxcontained in the exhaust gas is arranged at upstream of the NOxselective reduction catalyst 14. An intermediate product consisting of binding molecules of hydrocarbon molecules greater than an equivalence ratio for one NOxmolecule and NH2is generated by supplying the fuel in mist form to the NOxstorage type catalyst 12 and by reacting NOxoccluded in the NOxstorage type catalyst 12 and the supplied fuel on the NOxstorage type catalyst 12. The intermediate product is adsorbed by the NOxselective reduction catalyst 14 and NOxin the exhaust gas is reduced by the adsorbed intermediate product.

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