Oxide gas absorbing arrangement and method
AssigneeVolkswagen Aktiengesellschaft
InventorWolfgang Held
Life of this patent
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Abstract
In the oxide gas absorbing arrangement disclosed in the specification, metal foils having a thickness ≦0.05 mm are coated with an oxide gas absorbing layer containing gamma aluminum oxide. One metal foil is corrugated and joined to a smooth foil and the combined foils are rolled into a cylinder to provide parallel gas passages in which exhaust gases are exposed to the oxide gas absorbing layer. To enhance absorption turbulence is created in the gas passages by twisting the cylinder to narrow and contort the individual passages.
Claims16
A method for removing at least one nitrogen oxide (NOx) from the exhaust gas of an internal combustion engine, comprising the steps of:
- (a) operating an internal combustion engine to produce an exhaust gas flow containing oxygen;
- (b) passing exhaust gas containing oxygen over an oxide gas absorbing layer on a support member having a wall thickness ≦160 microns;
- (c) storing the NOx in the absorbing layer;
- (d) heating the absorbing layer to a predetermined temperature of at least 500° C. during the operation of the engine;
- (e) forming an exhaust gas from the internal combustion engine which is poor in oxygen and/or an exhaust gas having a stoichiometric excess of a reducing agent;
- (g) desorbing the NOx from the absorbing layer and reducing the NOx in the exhaust gas which is poor in oxygen or has a stoichiometric excess of reducing agent while the absorbing layer is at a temperature equal to or above the predetermined temperature;
- (h) forming an exhaust gas flow containing oxygen;
- (i) terminating heating of the absorbing layer to the predetermined temperature;
- and
- (j) repeating steps (c) through (h).
A method for removing at least one nitrogen oxide (NOx) from the exhaust gas of an internal combustion engine comprising the steps of:
- (a) operating the engine to produce an exhaust gas flow containing oxygen;
- (b) passing exhaust gas containing oxygen over an absorbing layer on a support member having a wall thickness ≦160 microns;
- (c) storing the NOx in the absorbing layer;
- (d) determining whether a temperature representative of the temperature of the absorbing layer is equal to or above a predetermined temperature of at least 500° C.;
- (e) forming an oxygen-poor exhaust gas flow and/or an exhaust gas flow with a stoichiometric excess of reducing agent while the absorbing layer is at a temperature equal to or above the predetermined temperature;
- (f) desorbing the NOx from the absorbing layer and reducing the NOx in the oxygen-poor exhaust gas and/or in the exhaust gas flow having a stoichiometric excess of reducing agent while the absorbing layer is at a temperature equal to or above the predetermined temperature;
- (g) forming an exhaust gas containing oxygen;
- and
- (h) repeating steps (c) through (g).
Dependencies are inferred from the claim text.