Combatting air pollution
AssigneeJohnson Matthey Public Limited Company
InventorsGuy Richard Chandler, Alan Francis Diwell, Raj Rao Rajaram
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Abstract
In the control of pollutants such as NOx in the exhaust gases from internal combustion engines, ozone is reacted with NO to form NO2, which is then reduced catalytically to N2, by reacting NO2 with ammonia. The NO2 produced can react with the particulates of Diesel engine to exhaust gas to regenerate a particulate filter.
Claims21
A method of combatting air pollution from an internal combustion engine whose exhaust gas contains NO, which method comprises contacting the exhaust gas containing NO with ozone to react the NO with the ozone to produce NO2 and reducing the NO2 to nitrogen.
A method according to any one of the preceding claims wherein the engine is a lean-burn engine, and NO2 produced is selectively catalytically reduced to nitrogen.
A method according to any one of the preceding claims wherein the NO is reacted with the ozone at a temperature of from ambient temperature to 200° C.
A method according to any one of the preceding claims wherein the exhaust gas contacting the ozone contains 2-200 parts per million by volume of SO2.
A method according to any one of the preceding claims wherein the NO is reacted with the ozone in the absence of platinum.
An internal combustion engine whose exhaust apparatus contains means to contact exhaust gas containing NO with ozone to react the NO with the ozone to produce NO2 and means to reduce the NO2 to nitrogen.
Dependencies are inferred from the claim text.