Plasma fuel processing for NOx control of lean burn engines
AssigneeEngelhard Corporation
InventorsEdward N. Balko, Kenneth E. Voss
Life of this patent
Estimating the term…
Abstract
A highly reactive reducing gas mixture is produced from vehicle fuel and introduced into the exhaust gas of an internal combustion engine operated at lean burn conditions and passed over a reducing catalyst to convert NOX emissions to benign emissions. Preferably, fuel with oxygen present in a carrier gas is metered into a plasma reactor having a bed of dielectric particles which prevent formation of coke as the fuel is reacted. The plasma induces a number of simultaneous reactions with the fuel to produce a substantial amount of oxygenated and non-oxygenated, unbranched organic molecules at relatively low temperatures that are highly reactive and ideally suited for use as a reducing agent in an SCR catalyst.
Claims43
A system for converting noxious emissions in the exhaust stream produced by an internal combustion engine operating at lean air/fuel ratios into non polluting emissions comprising:
- a) a non-thermal plasma reaction chamber generating a non-thermal plasma through which a portion of liquid engine fuel passes for conversion of the fuel portion into a reactive gaseous reductant;
- b) a valve for metering the fuel into said non-thermal plasma reaction chamber so that said gaseous reductant is produced at a rate correlated to the NOx emissions produced by said engine;
- c) a reducing catalyst downstream of said non-thermal plasma reaction chamber through which the exhaust stream passes for converting said NOx to N2;
- and,
- d) an exhaust duct portion from said non-thermal plasma reaction chamber to said exhaust stream for providing fluid communication of said exhaust gases and said gaseous reductant to said reducing catalyst in an externally unaltered state.
A system for converting noxious emissions in the exhaust stream produced by an internal combustion engine operating at lean air/fuel ratios into non polluting emissions comprising:
- a) a non-thermal plasma reaction chamber generating a non-thermal plasma through which a portion of liquid engine fuel passes for conversion of the fuel portion into a reactive gaseous reductant;
- b) a valve for metering the fuel into said non-thermal plasma reaction chamber so that said gaseous reductant is produced at a rate correlated to the NOx emissions produced by said engine;
- c) a reducing catalyst downstream of said non-thermal plasma reaction chamber for converting said NOx to N2~
- d) an exhaust duct portion from said non-thermal plasma reaction chamber to said exhaust stream for providing fluid communication of said gaseous reductant and said exhaust gases to said reducing catalyst in an externally unaltered state;
- and,
- e) said fuel is diesel fuel, said engine is a diesel engine and further including means to supply a carrier gas containing oxygen with said fuel to said non-thermal plasma reaction chamber to generate a reactive reductant mixture.
A system for reduction of NO in the exhaust cases produced by an internal combustion engine operating at lean conditions comprising:
- a) reducing means for producing from fuel used by said engine a reactive mixture in gaseous form, having more than 50% hydrocarbons by composition selected from at least one class of the group consisting of i) unbranched aliphatics having at least 7 carbon atoms in each molecule;
- ii) olefins and iii) oxygenates;
- b) a duct downstream of said engine from said reducing means for introducing said reactive mixture into said exhaust gas;
- c) a catalyst for reducing oxides of nitrogen to N2 downstream of said duct;
- and,
- d) said reducing means further including means for supplying a carrier gas containing oxygen with said fuel to cause a substantial portion of said reactive mixture to be a reactive oxygenate gaseous reductant.
A method for converting NOX emissions produced as products of combustion by an internal combustion engine operating at lean air-fuel ratios comprising the steps of:
- a) providing a plasma reactor chamber having first and second electrodes with an electrical power supply connected thereto for generating an electrical potential therebetween, said power supply regulated to produce a non-thermal plasma between said electrodes;
- b) metering an amount of diesel fuel into and out of said reaction chamber at an elevated temperature between said electrodes to cause said fuel to react and form a gaseous reductant;
- c) injecting said gaseous reductant into said exhaust stream;
- and,
- d) thereafter immediately passing said exhaust stream with said reducing stream through a reducing catalyst to produce N2.
A method for converting NOx emissions from an internal combustion diesel engine operated at lean conditions comprising the steps of:
- a) reacting a portion of the diesel fuel in a non-thermal plasma to produce a reactive gas mixture having more than 50% reactive hydrocarbons by composition, said reactive hydrocarbons including at least one class selected from the group consisting of i) unbranched aliphatics having at least 7 carbon atoms per molecule, ii) olefins and iii) oxygenates;
- b) metering said reducing gas with the exhaust gas;
- c) thereafter passing said exhaust gas with said reducing gas over a catalyst to convert any nitrous oxide emissions to N2;
- and,
- d) step (a) includes adding a carrier gas containing oxygen with said diesel fuel to said non-thermal plasma to produce in said reducing gas a substantial number of oxygenated short chain organic molecules forming a gaseous reactive mixture.
A system for converting noxious emissions including NOX produced by a diesel internal combustion engine comprising;
- a) a non-thermal plasma reaction chamber having a first ground electrode and a second insulated electrode and an electrical power supply with control to supply a voltage between said first and second electrodes, an inlet in fluid communication with the space between said electrodes and an outlet in fluid communication with the space between said electrodes and spaced from said inlet;
- b) a pump for injecting a metered portion of the fuel used in the diesel engine with a carrier gas containing oxygen to said inlet;
- c) a duct in fluid communication with said exhaust gases and said outlet for metering gaseous reductants produced by cracking said fuel in the presence of oxygen within said non-thermal plasma reaction chamber into said exhaust gases;
- d) a first reducing catalyst downstream of said duct receiving said exhaust gases with said gaseous reductants for reducing said NOX emissions to benign emissions;
- and
- e) a second catalyst for converting any noxious emissions in said exhaust gases not reduced to harmless emissions in said first catalyst.
Dependencies are inferred from the claim text.