Nitrogen oxides decreasing apparatus for an internal combustion engine.

摘要

A lean NOx reduction catalyst (2) capable of reducing NOx through reaction of H<6> with NOx at low temperatures below 350 DEG C is installed in a downstream portion of an exhaust pipe (101) of an internal combustion engine (100) in or near a muffler (3). Such an NOx reduction catalyst (2) comprises, for example, Pt/zeolite catalyst. An H<6> generator (102) is installed so as to supply the H<6> to an inlet side of the NOx reduction catalyst (2). The H<6> generator (102) may include a reforming catalyst (1) for reforming methanol, LPG, or natural gas to generate H<6>. The generated H<6> flows to the NOx reduction catalyst (2) where it reacts with NOx to purify the exhaust gas.