IMPROVED METHOD FOR HEATING CATALYTIC CONVERTERS OF VEHICLES TO ATTAIN ULTRA-LOW EMISSIONS

THE THREE-WAY CATALYTIC CONVERTER IS THE MOST IMPORTANT DEVICE MAKING TODAY'S AUTOMOBILES COMPLY WITH EXISTING EMISSION LAWS. THE FIRST TWO OR THREE MILES IN A TYPICAL 22-MINUTE, 12-MILE COMUTE IN TODAY'S VEHICLES RESULT IN THE EMISSION OF HALF OF THE TOTAL NON-METHANE HYDROCARBONS, WHICH RESULT IN THE PRODUCTION OF URBAN SMOG, AS WELL AS HALF OF THE TOXIC CO EMISSIONS. THIS OCCURS BECAUSE THE CATALYST IN THE CONVERTER WILL OPERATE INEFFECTIVELY UNTIL IT REACHES ITS OPTIMAL OPERATING TEMPERATURE. TO MEET NEW CALIFORNIA AND FEDERAL STANDARDS SPECIFIED FOR TRANSITIONAL LOW EMISSION VEHICLES, LOW EMISSION VEHICLES, AND ULTRA-LOW EMISSION VEHICLES, NEW TECHNOLOGIES ARE PRESENTLY BEING DEVELOPED TO LOWER THE WARM-UP TIME FOR CATALYTIC CONVERTERS. THIS IS REQUIRED TO BRING ABOUT SIGNIFICANT REDUCTIONS IN EMISSIONS OF HC'S PRIMARILY AND CO AND TO A LESSER EXTENT IN NOX. TECHNOLOGIES INVOLVING "PASSIVE" AND "ACTIVE" METHODS FOR RAPIDLY BRINGING CATALYTIC CONVERTERS TO USEFUL OPERATING TEMPERATURES (250 DEGREES CENTIGRADE UNDER COLD-START CONDITIONS (NOMINALLY -10 DEGREES CENTIGRADE TO 25 DEGREES CENTIGRADE) ARE CURRENTLY BEING INVESTIGATED. HOWEVER, ALL OF THESE TECHNOLOGIES, INCLUDING "CLOSE-COUPLED" CATALYTIC CONVERTERS, ON-BOARD HEAT STORAGE SYSTEMS, EXHAUST GAS IGNITION APPROACH AND ELECTRICALLY HEATED CONVERTERS SUFFER FROM VARIOUS DISADVANTAGES AND DRAWBACKS. IN THIS PROPOSSAL, A NEW CHEMICAL METHOD OF RAPIDLY HEATING CATALYTIC CONVERTERS IS PROPOSED THAT ADDRESSES THE WEAKNESSES OF THE ALTERNATIVE TECHNOLOGIES. BASICALLY THE NEW METHOD INVOLVES USING AN ON-BOARD HYDROGEN BLEED INTO THE EXHAUST SYSTEM UPSTREAM OF THE CATALYTIC CONVERTER WHICH WILL INSTANTLY ALLOW THE CATALYST TO REACH ITS LIGHT-OFF TEMPERATURE.