Combustion controlled nox reduction method and device

Abstract

In this invention, there is provided a method for reducing NOx emission from an internal combustion engine designed to produce a given amount of power and a method for improving fuel efficiency by providing an intake stream of oxygen-enriched air and keeping the amount of power output the same so that the combustion temperature in the engine is lower.

What is claimed is: 
     
         1 . A method for reducing air pollutants from an internal combustion engine of the type designed for providing a given power output based upon the combustion of hydrocarbon fuel in air, the method comprising:
 providing an oxygen-enriched intake air stream to an internal combustion engine,   maintaining the output power at the given power output according to the design of the engine,   combusting the oxygen enriched air with fuel in the engine at a temperature lower than the normal combustion temperature for the engine when burning air having ambient oxygen content so that a rate of fuel energy conversion results due to the oxygen enriched air at the lower temperature that is essentially the same rate of fuel energy conversion as would normally result from combusting the fuel with air having ambient oxygen content, wherein the amount of thermal NO x  produced in exhaust gas from the engine is reduced due to the lower combustion temperature.   
     
     
         2 . The method of  claim 1 , wherein the oxygen-enriched intake air comprises a mixture of nitrogen and oxygen and the oxygen concentration is at least 25% oxygen. 
     
     
         3 . The method of  claim 1 , wherein
 the oxygen-enriched air stream is provided by one or more methods of oxygen-air stream enrichment selected from the group of oxygen enrichment methods including supplying compressed oxygen into the engine air intake, supplying enriched oxygen intake air into the engine by molecular membrane separation of from enriched oxygen air from enriched nitrogen air, supplying enriched oxygen intake air into the engine by separating oxygen and nitrogen gases using a gas separation membrane, supplying enriched oxygen intake air into the engine by separating oxygen and nitrogen gases using a molecular sieve, supplying enriched oxygen intake air into the engine by separating oxygen and nitrogen by using a filter, supplying enriched oxygen intake air into the engine by separating oxygen and nitrogen by using a gas absorption separator, supplying enriched oxygen intake air into the engine by separating oxygen and nitrogen by using a pressure swing separator, and supplying enriched oxygen intake air into the engine by separating oxygen and nitrogen by gases using any combinations thereof.   
     
     
         4 . A method of improving fuel efficiency in a combustion engine comprising:
 adapting an oxygen-enriching apparatus to a combustion engine;   providing an air stream from the oxygen-enriching apparatus to the combustion engine intake; and   combusting fuel with the oxygen-enriched air.   
     
     
         5 . An apparatus for reducing air pollutants from combustion engines comprising:
 a first end, a second end, and a middle portion, wherein   the first end comprises a connector capable of being adapted to the intake of a combustion engine;   the second end comprises an interface exposed to an air source; and   a middle portion communicating air from the second end to the first end and comprising an oxygen enhancer, such that the air communicated from the air source to the engine has enhanced oxygen content;   
     
     
         6 . The apparatus of  claim 5 , wherein
 the oxygen enhancer of the middle portion further comprises one or more oxygen enhancement mechanisms selected from a molecular membrane, a gas separation membrane, a molecular sieve, a filter, a gas absorption separator, a pressure swing separator, and any combinations thereof.   
     
     
         7 . The apparatus of  claim 5 , wherein
 the air source is comprised of compressed oxygen.   
     
     
         8 . A method for reducing NO x  produced in the exhaust from an internal combustion engine upon the combustion of a given quantity of hydrocarbon fuel in air to provide an engine designed output power, the method comprising:
 enriching the oxygen in the intake air to an internal combustion engine,   maintaining the given quantity of hydrocarbon fuel and output power at the designed output power for the engine,   combusting the oxygen enriched air with fuel in the engine at a lower temperature than the normal combustion temperature for the engine when burning air having ambient oxygen content, wherein the lower temperature comprises a temperature defined by the equation:
     Ae   −E/RTs   X   As   X   B   =ΔC   A   /Δt=Ae   −E/RTe   X   Ae   X   B    
   where:   A=the activation constant for the combustion reaction;   e=is the exponential value;   E=is the energy constant for the combustion reaction;   R=is the rate constant for the combustion reaction;   Ts=is the standard average combustion temperature at which the engine is designed to burn the fuel to produce the expected output power;   X As =is the concentration of oxident in the air to be combusted;   ΔC A /Δt=is the rate of conversion of fuel and oxidant to exhaust gases;   Te=is the lower temperature of the combustion to have the same rate of conversion of fuel and oxidant when the concentration of oxidant is increased;   X Ae =is the increased concentration of oxidant;   so that a rate of fuel energy conversion results due to the oxygen enriched air at the lower temperature that is essentially the same rate of fuel energy conversion as would normally result from combusting the fuel with air having ambient oxygen content, wherein the amount of thermal NO x  produced in exhaust gas from the engine is reduced due to the lower combustion temperature.