Internal combustion engine exhaust treatment having a single valve directing exhaust to dual NOx traps
AssigneeShell Oil Company
InventorsKe Liu, John G. Buglass
Life of this patent
Estimating the term…
Abstract
A single valve (23, 50) directs engine exhaust (11, 12) toward alternative NOx traps (19, 20) which are adjacent to either diesel particulate filters (40, 41) or low temperature water gas shift catalysts (63, 64). Syngas is either provided from a source (54) or by in-line catalytic partial oxidizers (23, 24) which may have diesel oxidation catalysts ahead of them in the flow and which receive fuel from the engine fuel source (26) through nozzles (27, 28).
Claims1
Apparatus for reducing oxides of nitrogen (NOx) in the exhaust of an internal combustion engine which has a source of fuel and generates exhaust in an exhaust pipe, comprising:
- first and second NOx traps which reduce NOx in exhaust that passes therethrough;
- a single exhaust valve having two outlets and at least one inlet, said exhaust pipe connected to said one inlet, said valve having at least a first position in which substantially all of the exhaust flowing in said exhaust pipe is directed through a first one of said outlets to said first one of said NOx traps and a second position in which substantially all of the exhaust flowing in said exhaust pipe is directed through a second one of said outlets to a second one of said NOx traps;
- a respective hydrocarbon fuel reformer disposed between each of said outlets and each of said NOx traps, each reformer receiving fuel from said source;
- and
- a pair of oxidation catalysts, each disposed in serial flow relationship between a respective one of said reformers and a related one of said outlets;
- said valve alternatively directing said exhaust to one or the other of said NOx traps through a corresponding one of said reformers.
Dependencies are inferred from the claim text.