Reducing oxides of nitrogen using reformate generated from engine fuel, water and/or air

Abstract

Inlet air (15) humidified in an air bubbling (or other) humidifier (35) that receives water from a tank (36) is sent to a hydrogen generator (27) along with vaporized (23) diesel fuel (22) to produce hydrogen and carbon monoxide (28) for either (a) mixing with the mainstream of exhaust (18) fed to a catalytic converter (30) or (b) regenerating a pair of NOx adsorption traps (38, 39), thereby reducing oxides of nitrogen (NOx), to provide system exhaust (32) which may have less than 0.40 grams / bhp / hr of NOx and 0.28 grams / bhp / hr of non-methane hydrocarbons. In other embodiments, unhumidified air mixed with fuel feeds a homogeneous non-catalytic partial oxidizer (27) to provide the required hydrogen and carbon monoxide.

Description

[0001] This is a continuation-in-part of U.S. patent application Ser. No. 10 / 166,860 filed on Jun. 11, 2002.[0002] This invention relates to reducing oxides of nitrogen (NOx) in the exhaust of hydrocarbon-fueled, internal combustion engines (such as gasoline or diesel engines), and more particularly to using hydrogen generators, such as catalytic partial oxidizers (CPOx), non-catalytic (homogeneous) partial oxidizers (POx), or auto thermal reformers (ATR), to generate from engine fuel, water and / or air, streams including hydrogen and carbon monoxide for reducing NOx in catalytic converters or regenerating NOx trap adsorbents.[0003] The Environmental Protection Agency (EPA) has set, for 2007 and beyond, vehicle internal combustion engine emission requirements; one exemplary requirement for diesel engines, is NOx and non-methane hydrocarbons below 0.20 grams bhp-hr and 0.14 grams / bhp-hr, respectively. This contrasts with current standards of 4.0 grams / bhp-hr and 1.3 grams / bhp-hr, resp...

AI Technical Summary

Benefits of technology

[0006] Objects of the present invention include: improvement in the reduction of NOx to nitrogen and other harmless gases; achieving NOx reduction that meets EPA 2007 NOx emission requirements; simple, low-cost hydrogen generation for NOx reduction; and generation of hydrogen in and for an internal combustion engine exhaust emission reduction system, from only fuel already available with the engine in addition to water and / or air.

Problems solved by technology

There currently are no catalyst formulations which are able to adequately reach these restrictive standards; significant development will be required to reduce the cost and improve performance of new catalyst formulations.

The problem is that there is no infrastructure in place to provide the urea solution at stations where fuel, particularly diesel fuel and gasoline, is obtained.

All of the aforementioned NOx reduction techniques are complicated and expensive.

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