The exhaust gas purification device according to the present invention utilizes two NO x absorbents in order to remove NO x from the exhaust gas of an engine operated at a lean air-fuel ratio. The NO x absorbents are disposed, in series, in the exhaust passage of the engine and a nozzle for supplying a reducing agent is disposed in the exhaust passage at a position between the two NO x absorbents. Further, the device includes switching valves for changing the direction of the exhaust gas flow in the exhaust gas passage. When the switching valves are set to direct the exhaust gas flow to one direction, the exhaust gas first flows through one of the NO x absorbents (first NO x absorbent), and after passing through the first NO x absorbent, the reducing agent is supplied to the exhaust gas before it flows into the other NO x absorbent (second NO x absorbent). Thus, the first NO x absorbent absorbs NO x in the exhaust gas, and the NO x absorbed by the second NOabsorbent is released from the second NO x absorbent. When the switching valves are switched, the exhaust gas flows in the opposite direction, and flows through the second NO x absorbent and the first NO x absorbent in this order. In this case, the second NO x absorbent absorbs NO x in the exhaust gas, and the NO x absorbed by the first NO x absorbent is released and reduced to N 2 . Therefore, by reversing the direction of the exhaust gas periodically, the absorbing operation of NO x and releasing/reducing operation of NO x are performed by two NO x absorbents alternately. Thus, it becomes possible to remove NO x in the exhaust gas continuously while the NO x absorbents are prevented from being saturated by the absorbed NO x .

Exhaust gas purification device for an engine

A contact structure, useful as a distillation structure, has a rigid frame made of two substantially vertical duplicate grids (22) spaced apart and held rigid by a plurality of substantially horizontal rigid members (20) and a plurality of substantially horizontal wire mesh tubes (10) mounted to the grids to form a plurality of fluid pathways among the tubes. For use as a catalytic distillation structure, which serves as both the distillation structure and the catalyst, at least a portion of the wire mesh tubes contain a particulate catalytic material (30). The catalyst within the tubes provides a reaction zone where catalytic reactions may occur and the wire mesh provides mass transfer surfaces to effect a fractional distillation. The spacing elements provide for a variation of the catalyst density and loading and structural integrity.

Catalytic distillation structure.

A combination catalytic converter and heat exchanger unit that controls the temperature of one or more catalytic converters within their efficient conversion operating temperature ranges. The unit includes a plurality of spaced apart tubes through which the exhaust emissions flow through the unit. Each of the plurality of tubes includes a substrate on which is formed a catalyst that reduces or eliminates harmful by-products in the exhaust emissions. A cooling system, such as a fan, forces a cooling fluid, such as air, around the tubes to cool the catalyst to be within its efficient operating temperature range. The tubes have a suitable diameter that allows the center of the tubes to be effectively cooled. The speed of the fan is controlled to variably adjust the temperature of the exhaust emissions in response to various input data, such as the temperature of the exhaust emissions at different locations in the exhaust path, engine speed and load, and the type of catalyst being used. The plurality of tubes can incorporate two or more catalysts that have different operating ranges so as to control the effectiveness of the conversion for increased efficiency and reduction of energy consumption. It is also possible to provide supplemental electrical heat to the plurality of tubes to extend the duration whereby the catalytic converter is operating within its efficient conversion window.

Combination catalytic converter and heat exchanger that maintains a catalyst substrate within an efficient operating temperature range for emmisions reduction

A system for adjusting the temperature of the exhaust emissions from an internal combustion engine so that it is at a temperature that maintains one or more catalysts at their effective operating temperature. This has particular application for NOx control from any lean-burn engine. The system includes a heat exchanger that cools the exhaust emissions by forced air from a variable speed fan. The cooled exhaust emissions are directed from the heat exchanger to the catalyst for conversion. The fan speed is controlled to adjust the amount of cooling of the exhaust emissions in response to various input data, such as the temperature of the exhaust emissions at different locations in the exhaust pipe, engine speed, engine load and the catalyst being used. Two or more catalysts can be incorporated at different locations along the exhaust path and have different operating temperatures so as to control the effectiveness of exhaust emissions conversions for increased efficiency and reduced energy consumption. The incorporation of a temperature-controlled catalytic conversion system allows the catalysts to be placed closer to the exhaust manifold, thus reducing cold-start emissions and extending catalyst durability and long-term emissions control for any heat engine application.

System and method for controlling exhaust gas temperatures for increasing catalyst conversion of NOx emissions

An exhaust gas purifier for purifying combustion gases of engines, the device comprising at least one composite sheet which is formed by sandwiching a catalyst coated sheet of cloth between a pair of supporting nets of heat resistive metal, the composite sheet being disposed in an exhaust pipe in a manner such that the exhaust gas flows in the direction of and along the surfaces of the composite sheet and that the gas contacts the catalyst sheet through the supporting net. The composite sheet(s) are shaped or disposed in a rolled sheet with spacer means to form gas flow path between its layers, or a set of coaxial tubes of the composite sheet disposed with spaces for gas-flow, or a set of parallel-disposed flat composite sheets with spaces for gas-flow. The device is advantageous in low resistivity for the gas flow.

Exhaust gas control equipment

A catalyst composition obtained by dispersing a power catalyst containing a hydrated oxide or oxides or manganese dioxide in an organic solution containing alkoxytitanate, alkoxy substituted organosilane or dimethyl polysiloxane or a catalyst composition obtained by dispersing a power catalyst in a heat-resisting paint prepared by utilizing a liquid compound having a siloxane bond as the vehicle. The catalyst is exposed moderately when it is adhered to a carrier when said catalyst composition is prepared by employing a catalyst whose principal components consist of manganese oxide or oxides and lead oxide or oxides and/or bismuth oxide or oxides, it is best suited for oxidation and purification of a waste gas containing carbon monoxide. Besides, catalyst reaction apparatuses prepared by making the foregoing catalyst composition adhere to a carrier consisting of plural metallic plates and connecting one end or both ends of said carrier with a metallic structure configured to be suitable for the purpose of cooling is effective in gas-solid heterogeneous catalytic reaction.

K Miyazaki

Papers

Catalytic reaction apparatus for purifying waste gases containing carbon monoxide