A method for controlling an exhaust after-treatment system based on NO.sub.2 medium adjustment includes the following steps: creating a diesel oxidation catalyst (DOC) reaction map, a diesel particulate filter (DPF) reaction map, and a selective catalytic reduction (SCR) reaction map; obtaining an SCR reaction temperature, desired SCR reaction efficiency, and obtaining NO.sub.2 demand according to the SCR reaction map; obtaining a DPF reaction temperature and differential pressure, and obtaining NO.sub.2 consumption from the DPF reaction map; obtaining NO.sub.2 production, and calculating NO.sub.2 input for SCR; if the NO.sub.2 input is not equal to the NO.sub.2 demand, calculating target NO.sub.2 production, obtaining a target DOC reaction temperature corresponding to the target NO.sub.2 production from the DOC reaction map, and adjusting a fuel injection rate so that the DOC reaction temperature is equal to the target DOC reaction temperature.

An engine emission treatment system incudes at least one out of an air inlet dust removal system (101), a tail gas dust removal system (102), and a tail gas ozone purification system. The tail gas dust removal system (102) has an inlet of the tail gas dust removal system, an outlet of the tail gas dust removal system, and a tail gas electric field device (1021). The tail gas ozone purification system has a reaction field (202), used for mixing an ozone stream and a tail gas stream for reaction. The engine emission treatment system may effectively treat engine emissions, so as to make the engine emissions cleaner.

A lean NO.sub.x trap catalyst and its use in an emission treatment system for internal combustion engines is disclosed. The lean NO.sub.x trap catalyst comprises a first layer for storing nitrogen oxides (NOx) under lean exhaust gas conditions and releasing and/or reducing stored NOx during rich exhaust gas conditions, and a second layer, said second layer comprising a first zone for oxidizing carbon monoxide (CO) and/or hydrocarbons (HC), and a second zone for oxidizing nitric oxide (NO), and a substrate having an inlet end and an outlet end.

The present disclosure describes methods for operating an EAS including a close coupled SCR unit, a downstream SCR unit, a diesel oxidation catalyst unit (DOC) and a diesel particulate filter (DPF). The methods utilize the close coupled SCR unit to manage NOx emissions from the EAS during regeneration of a diesel particulate filter (DPF).

An exhaust aftertreatment system for use with an over-the-road vehicle is disclosed. The exhaust aftertreatment system includes a flash-boil doser mounted to an exhaust conduit and a catalyst coupled to the exhaust conduit. The flash-boil doser configured to inject heated and pressurized reducing agent into an exhaust passageway defined by the exhaust conduit for distribution throughout exhaust gases passed through the exhaust conduit. The catalyst configured to react the reducing agent with the nitrous oxide in the flow of exhaust gases to provide treated exhaust gases with a reduced nitrous oxide amount.

An exhaust emission control device has at least one exhaust gas line, at least one particulate filter and/or at least one exhaust gas catalytic converter connected to the exhaust gas line, and a heated catalyst assembly arranged upstream of the particulate filter and/or the exhaust gas catalytic converter. The heated catalyst assembly is designed to react fuel with exhaust gas, and has a housing provided with an inlet and an outlet connected to the exhaust gas line such that a partial flow of the exhaust gas flowing in the exhaust gas line can be fed through the inlet into the housing and can be discharged from the housing through the outlet back into the exhaust gas line downstream of the inlet. An exhaust emission control device of this type may be used in conjunction with an internal combustion engine, and may be used for emission control of exhaust gas.

Disclosed are a honeycomb-like homo-type heterojunction carbon nitride composite material and a preparation method thereof, and an application of the honeycomb-like homo-type heterojunction carbon nitride composite material in catalytic treatment of waste gas. The preparation method includes the following steps: with two different carbon nitride precursors namely urea and thiourea as raw materials, weighing certain amounts of the urea and the thiourea, adding the urea and the thiourea into a crucible, adding a certain amount of ultrapure water, placing the crucible in a muffle furnace, and carrying out calcination molding. The honeycomb-like homo-type heterojunction carbon nitride prepared by the one-step method has good photocatalytic effect to catalytic degradation of NO; meanwhile, the honeycomb-like homo-type heterojunction carbon nitride composite material has the advantages of rich and easily-available production raw materials, good stability, reusability, etc., and has application prospects in the field of treatment of NO in the air.

Provided is an exhaust gas purification apparatus having a control device that monitors the transition of a detection value of each of an upstream NOx sensor and a downstream NOx sensor, and when the NOx purification rate of the SCR catalyst falls to a value of a first threshold or lower, generates an abnormality detection signal indicating that an over storage state has occurred in an SCR catalyst if the amount of change in the detection value of the upstream NOx sensor per unit time is at least a second threshold and the amount of change in the detection value of the downstream NOx sensor per unit time is at most a third threshold.

A three-way catalyst article, and its use in an exhaust system for internal combustion engines, is disclosed. The catalyst article for treating exhaust gas comprising: a substrate comprising an inlet end, an outlet end with an axial length L; an inlet catalyst layer beginning at the inlet end and extending for less than the axial length L, wherein the inlet catalyst layer comprises an inlet palladium component; an outlet catalyst layer beginning at the outlet end and extending for less than the axial length L, wherein the outlet catalyst layer comprises an outlet rhodium component; and wherein the outlet catalyst layer overlaps with the inlet catalyst layer.

An oxidation catalyst for treating an exhaust gas from a diesel engine comprises: a first washcoat region for oxidising carbon monoxide (CO) and hydrocarbons (HCs), wherein the first washcoat region comprises a first platinum group metal (PGM) and a first support material, and wherein the first washcoat region does not comprise manganese or an oxide thereof; a second washcoat region for oxidising nitric oxide (NO), wherein the second washcoat region comprises platinum (Pt), manganese (Mn) and a second support material comprising a refractory metal oxide, which is silica-alumina or alumina doped with silica in a total amount of 0.5 to 45% by weight of the alumina, wherein the platinum (Pt) is disposed or supported on the second support material and the manganese (Mn) is disposed or supported on the second support material; and a substrate having an inlet end and an outlet end, and wherein the first washcoat region is a first washcoat layer and the second washcoat region is a second washcoat layer, and the second washcoat layer is disposed on the first washcoat layer; and wherein when the oxidation catalyst comprises a hydrocarbon adsorbent, which is a zeolite, then the first washcoat region further comprises the hydrocarbon adsorbent.