| 摘要 |
An engine system comprising: a diesel engine having particulate emissions such that a particle material (PM) reduction of < 50% is required to meet Tier 4 final and/or Stage IV or equivalent emissions standards PM limit for off-highway engine systems; a reductant introduction point downstream of the diesel engine and in fluid flow communication therewith with no intervening treatment systems; a conduit immediately downstream of the reductant introduction point having sufficient length to enable mixing of the reductant with exhaust gases of the engine, an SCR immediately downstream of the conduit, the with good low temperature activity such that a diesel oxidation catalyst (DOC) is not needed to make the required proportions of NO to NO, to meet the NOx limit of the Tier 4 final / Stage IV emissions standards for off-highway engine systems; an ammonia slip catalyst (ASC) downstream of the SCR acting to remove excess ammonia to meet the limits under Tier 4 final / Stage IV off-highway engine systems for ammonia; and wherein the ASC and the SCR in combination act to remove excess PM to meet the limits under Tier 4 final / Stage IV off-highway engine systems for PM. An off-highway vehicle may incorporate the engine system. |
