An internal combustion engine wherein an HC treatment catalyst (12) having the function of adsorbing the HC in the exhaust gas is arranged upstream of the NOx selective reducing catalyst (14), an urea aqueous solution fed from the reducing agent feed valve (15) is arranged upstream of the HC treatment catalyst (12), urea, and NOx contained in the exhaust gas, and HC adsorbed on the HC treatment catalyst 12 are reacted with each other to form intermediate products having cyano groups, oximes, and amino groups, and these intermediate products are sent to the NOx selective reducing catalyst (14).

Exhaust purification device of internal combustion engine

Method and apparatus for thermal management of vehicle exhaust systems

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

A heated and insulated catalytic converter includes a heat storage device and a control system for maintaining an elevated temperature while the engine is not operating. The control system may also include control of flaps to allow cool air to circulate to prevent overheating and timers.

Heated insulated catalytic converter with air cooling

A system for controlling the catalyst temperature of a catalytic converter mounted in an exhaust system of an internal combustion engine within a range appropriate for eliminating nitrogen oxides contained in engine exhaust gases. The system includes an encasing structure which is disposed about an exhaust pipe upstream of the catalytic converter and which is spaced from the exhaust pipe to form a gap into which an atmospheric air is selectively admitted. The encasing structure has air inlet and outlet passages communicating with the gap and opening to the atmosphere. The flow of atmospheric air into the gap is controlled by first and second valve plates operatively disposed in the air inlet and outlet passages respectively, the first and second valve plates being controlled by a control means comprising a diaphragm unit communicating with an intake manifold of the engine, a solenoid valve for controlling the fluid communication between the diaphragm unit and the intake manifold, and a temperature sensitive switch responsive to the catalyst temperature for controlling the solenoid valve.

M Onoda

Papers

Temperature control system for catalytic converter