US 6,051,040 AGranted

Method for reducing emissions of NO.sub.x and particulates from a diesel engine

AssigneeClean Diesel Technologies, Inc.

InventorJeremy D. Peter-Hoblyn

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Abstract

A method improves the operation of a diesel engine through the use of a fuel additive, a diesel particulate trap and a NO.sub.x -reducing catalyst. The operation of the NO.sub.x -reducing catalyst is enhanced by the introduction of urea or like compound upstream of the catalyst at temperatures effective for non-catalytic NO.sub.x reduction and the generation of ammonia. The additive comprises fuel-soluble compositions of platinum group metal in effective amounts to lower the emissions of unburned hydrocarbons and carbon monoxide from the trap. The catalytic activity provided to the exhaust system by the fuel additive is selective and preferably reduces the oxidation of SO.sub.2 to SO.sub.3. The platinum group metal compositions are preferably added in amounts effective to provide concentrations of the metal in the fuel of less than 1 part per million (ppm). Lithium and/or sodium compositions can be used in amounts effective to reduce the trap regeneration temperature, e.g. concentrations to provide about 1 to 100 ppm lithium metal, and/or 1 to 30 ppm sodium metal.

Claims18

Dependent claims

A method for operating a diesel engine with reduced emissions of particulates and NO.sub.x, comprising:

(a) adding to a diesel fuel, a fuel-soluble composition of platinum group metal in effective amounts such that the gases produced by combustion selectively catalyze the exhaust system, including a particulate trap, effectively to lower the emissions of unburned hydrocarbons and carbon monoxide, said platinum group metal composition comprising a fuel soluble organic compound which
I) is resistant to breakdown under ambient temperatures;
ii) is substantially free of phosphorus, arsenic, antimony, or halogens;
iii) has a partition ratio sufficient to maintain preferential solubility in the fuel;
iv) has a breakdown temperature of at least about 122.degree. F. and
v) a partition ratio of at least about 25;
(b) combusting the diesel fuel in a diesel engine resulting in the production of diesel combustion gases containing NO.sub.x and particulates;
(c) injecting into the combustion gases within the cylinder of the diesel engine near the end of the power stroke where the temperature is within the range of from 1600.degree. and 2000.degree. F. an aqueous solution of a NO.sub.x -reducing composition which produces ammonia by the decomposition of the NO.sub.x -reducing composition selected from the group consisting of urea, cyanuric acid, dicyanimide, calcium cyanamide, and mixtures of these, the temperature being effective to reduce the level of NO.sub.x in the combustion gases and produce ammonia by the decomposition of the NO.sub.x -reducing composition;
(d) passing the combustion gases containing ammonia through a particulate trap comprised of a gas permeable material to reduce the level of particulates;
and
(e) passing the combustion gases through a NO.sub.x -reduction catalyst to reduce NO.sub.x and ammonia produced by decomposition of the NO.sub.x -reducing composition.

8 more elements

A method for operating a diesel engine with reduced emissions of particulates and NO.sub.x, comprising:

(a) adding to a diesel fuel, a fuel-soluble composition of platinum group metal in effective amounts such that the gases produced by combustion selectively catalyze the exhaust system, including a particulate trap, effectively to lower the emissions of unburned hydrocarbons and carbon monoxide, said platinum group metal composition comprising a fuel soluble organic compound which
I) is resistant to breakdown under ambient temperatures;
ii) is substantially free of phosphorus, arsenic, antimony, or halogens;
iii) has a partition ratio sufficient to maintain preferential solubility in the fuel;
iv) has a breakdown temperature of at least about 122.degree. F.;
and
v) a partition ratio of at least about 25;
(b) combusting the diesel fuel in a diesel engine resulting in the production of diesel combustion gases containing NO.sub.x and particulates;
(c) passing the gases to an exhaust system at a temperature of from about 752.degree. to about 2000.degree. F.;
(d) injecting into the combustion gases an aqueous solution of a NO.sub.x -reducing composition which produces ammonia by the decomposition of the NO.sub.x -reducing composition selected from the group consisting of urea, cyanuric acid, calcium cyanamide and mixtures of these, whereby ammonia is produced by the decomposition of the NO.sub.x -reducing composition;
(e) passing the combustion gases containing ammonia through a particulate trap comprised of a gas permeable material to reduce the level of particulates;
and
(f) passing the combustion gases through a NO.sub.x -reduction catalyst to reduce NO.sub.x and ammonia produced by decomposition of the NO.sub.x -reducing composition.

10 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/978,687Filed 26 Nov 1997 · continuation
Priority: 28 Dec 1988
Granted: 18 Apr 2000
Term ends: Not estimatedThe source records don’t support an estimate.

Classification64 codes

F02D 19/12
Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible…
B01D 53/9418
Processes characterised by a specific catalyst: for removing nitrogen oxides by selective catalytic reduction [SCR] using a reducing agent in a…
B01D 53/944
By catalytic processes: simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts
B01D 53/9477
Removing one or more of nitrogen oxides, carbon monoxide, or hydrocarbons by multiple successive catalytic functions; systems with more than one…:…

Family

Serial291,245Parent of this continuation · filed 28 Dec 1988
Serial794,329Parent of this continuation-in-part · filed 12 Nov 1991
Serial808,435Parent of this continuation-in-part · filed 16 Dec 1991
Serial003,245Parent of this continuation-in-part · filed 11 Jan 1993
Serial089,838Parent of this continuation · filed 12 Jul 1993
Serial518,251Parent of this continuation · filed 23 Aug 1995
US 6,051,040 AThis patent

From the US filing history. Foreign family members aren’t listed.