US20070157607A1 - Clean air system - Google Patents

Clean air system Download PDF

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Publication number
US20070157607A1
US20070157607A1 US11/651,709 US65170907A US2007157607A1 US 20070157607 A1 US20070157607 A1 US 20070157607A1 US 65170907 A US65170907 A US 65170907A US 2007157607 A1 US2007157607 A1 US 2007157607A1
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US
United States
Prior art keywords
exhaust gas
fuel
stoichiometry
catalyst
controlling
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US11/651,709
Inventor
William Pfefferle
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Precision Combustion Inc
Original Assignee
Pfefferle William C
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pfefferle William C filed Critical Pfefferle William C
Priority to US11/651,709 priority Critical patent/US20070157607A1/en
Publication of US20070157607A1 publication Critical patent/US20070157607A1/en
Priority to PCT/US2008/000023 priority patent/WO2008085817A1/en
Assigned to PRECISION COMBUSTION, INC. reassignment PRECISION COMBUSTION, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: PFEFFERLE, WILLIAM C.
Abandoned legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/30—Controlling by gas-analysis apparatus
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9404—Removing only nitrogen compounds
    • B01D53/9409—Nitrogen oxides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/944—Simultaneously removing carbon monoxide, hydrocarbons or carbon making use of oxidation catalysts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B01D53/9495—Controlling the catalytic process
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • the present invention is generally directed to a method for achieving pollutant free operation of automotive engines and other sources of carbonaceous and nitric oxide pollutants. More specifically, the present invention is directed at controlling emissions of platinum oxides from catalytic converters.
  • the present invention comprises a method and apparatus for operating a catalytic converter system.
  • a catalytic converter such as used on present day automobiles, is operated on the fuel rich side of stoichiometric but with sufficient air to consume most of the hydrocarbons and carbon monoxide in the exhaust.
  • Non-methane hydrocarbon emissions of less than five ppm are achievable with carbon monoxide representing the bulk of residual fuel values.
  • platinum loss is negligible.
  • methane is readily converted in a fuel rich environment. It has now been shown that in fuel rich oxidation of methane, no measurable loss of platinum could be detected after more than 2000 hours of operation. In contrast, nearly all the platinum was lost in less than 200 hours running fuel lean.
  • the required control of exhaust gas stoichiometry is achievable such as by feedback of measured values from a universal oxygen sensor to a modern engine control computer. Test runs have demonstrated that high conversion levels of all three pollutants are achievable.
  • High mass transfer efficiency catalysts such as the short channel length catalysts of U.S. Pat. No. 5,051,241, allow high conversion of hydrocarbons and carbon monoxide even with low residual oxygen levels.
  • stoichiometry is controlled to supply sufficient oxygen to convert all but ten to two hundred ppm of the fuel values present.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Analytical Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Health & Medical Sciences (AREA)
  • Biomedical Technology (AREA)
  • Environmental & Geological Engineering (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

The present invention provides a method for controlling exhaust gas emissions including platinum, wherein exhaust gas is brought into contact with an emissions control catalyst and the oxygen content of the exhaust gas is controlled in order to maintain fuel rich stoichiometry close to the stoichiometric value.

Description

    FIELD OF THE INVENTION
  • The present invention is generally directed to a method for achieving pollutant free operation of automotive engines and other sources of carbonaceous and nitric oxide pollutants. More specifically, the present invention is directed at controlling emissions of platinum oxides from catalytic converters.
    • BACKGROUND OF THE INVENTION
  • Historically, great strides have been made in controlling automotive emissions. Early oxidation catalyst systems were very effective in controlling hydrocarbon and carbon monoxide emissions. However, it was soon recognized that control of nitrogen oxides (NOx) was also necessary. Because NOx control catalysts are typically ineffective under oxidizing conditions, two stage systems were used having a reducing first stage followed by an oxidizing second stage with added air. A major improvement was the development of three way catalysts and the system of dithering the fuel air ratio between rich and lean around the stoichiometric value. This allows both NOx reduction and oxidation of hydrocarbons and carbon monoxide, and has been the standard approach for many years. All these approaches have a serious flaw. Any period of lean operation will allow loss of platinum as platinum oxide. Thus it should be no surprise that European researchers have recently discovered widespread platinum contamination of the environment. This is a potentially serious problem since workers in a platinum refinery have developed serious allergic reaction to extremely low concentrations. Although a guard bed could be used to gather platinum, frequent replacement would likely be required.
  • Based on the foregoing, it is an objective of the present invention to provide a method and apparatus to eliminate loss of platinum from catalytic converters without impairing effectiveness.
    • SUMMARY OF THE INVENTION
  • The present invention comprises a method and apparatus for operating a catalytic converter system. In the method of this invention, a catalytic converter, such as used on present day automobiles, is operated on the fuel rich side of stoichiometric but with sufficient air to consume most of the hydrocarbons and carbon monoxide in the exhaust. It has now been found that as low or lower HC, CO and NOx emissions can be achieved using the method of the present invention as with dithering systems. Non-methane hydrocarbon emissions of less than five ppm are achievable with carbon monoxide representing the bulk of residual fuel values. In the absence of excess oxygen on the catalyst surface, platinum loss is negligible. Even methane is readily converted in a fuel rich environment. It has now been shown that in fuel rich oxidation of methane, no measurable loss of platinum could be detected after more than 2000 hours of operation. In contrast, nearly all the platinum was lost in less than 200 hours running fuel lean.
  • It has also been found that minor platinum emissions resulting from any failure of the control system can be captured by use of a guard bed of a material such as alumina down stream of the catalytic reactor. Note that available modern digital control systems have proven highly reliable.
  • In the present invention, the required control of exhaust gas stoichiometry is achievable such as by feedback of measured values from a universal oxygen sensor to a modern engine control computer. Test runs have demonstrated that high conversion levels of all three pollutants are achievable. High mass transfer efficiency catalysts, such as the short channel length catalysts of U.S. Pat. No. 5,051,241, allow high conversion of hydrocarbons and carbon monoxide even with low residual oxygen levels. Advantageously, stoichiometry is controlled to supply sufficient oxygen to convert all but ten to two hundred ppm of the fuel values present.
  • While the present invention has been described in detail with reference to providing a method for eliminating the loss of platinum from catalytic converters, other catalytic reactor configurations exhibiting the characteristics taught herein are contemplated. Therefore, the spirit and scope of the invention should not be limited to the description of the preferred embodiments described herein.

Claims (8)

1. A method for controlling exhaust gas emissions including platinum, comprising:
a) contacting the exhaust gas with an emissions control catalyst; and
b) controlling the oxygen content of the exhaust gas to maintain fuel rich stoichiometry close to the stoichiometric value.
2. The method of claim 1 wherein the catalyst is a three way catalyst.
3. The method of claim 1 wherein the catalyst is an oxidation catalyst.
4. The method of claim 1 wherein a universal oxygen sensor is used to measure exhaust gas stoichiometry.
5. The method of claim 4 wherein the measured exhaust gas stoichiometry is fed real time to a fuel flow control computer.
6. The method of claim 5 wherein the fuel control computer is programmed to maintain a constant fuel-air stoichiometry in transient operation.
7. The method of claim 6 wherein sufficient oxygen is present to consume all but between about ten and about two hundred ppm of the fuel values present.
8. A method for operating an automotive engine comprising:
a) controlling fuel flow in relation to air flow;
b) measuring exhaust gas stoichiometry using a universal oxygen sensor; and
c) adjusting fuel flow to maintain exhaust gas stoichiometry slightly on the rich side of stoichiometric.
US11/651,709 2006-01-11 2007-01-10 Clean air system Abandoned US20070157607A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US11/651,709 US20070157607A1 (en) 2006-01-11 2007-01-10 Clean air system
PCT/US2008/000023 WO2008085817A1 (en) 2007-01-10 2008-01-03 Clean air system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US75838006P 2006-01-11 2006-01-11
US11/651,709 US20070157607A1 (en) 2006-01-11 2007-01-10 Clean air system

Publications (1)

Publication Number Publication Date
US20070157607A1 true US20070157607A1 (en) 2007-07-12

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Family Applications (1)

Application Number Title Priority Date Filing Date
US11/651,709 Abandoned US20070157607A1 (en) 2006-01-11 2007-01-10 Clean air system

Country Status (2)

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US (1) US20070157607A1 (en)
WO (1) WO2008085817A1 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110138777A1 (en) * 2010-10-12 2011-06-16 Hungwen Jen Diesel engine exhaust treatment system and method including a platinum group metal trapping device
US8652429B2 (en) 2011-10-06 2014-02-18 Johnson Matthey Public Limited Company Oxidation catalyst for internal combustion engine exhaust gas treatment
US8668891B2 (en) 2011-12-12 2014-03-11 Johnson Matthey Public Limited Company Exhaust system for a lean-burn IC engine comprising a PGM component and a SCR catalyst
US8667785B2 (en) 2011-12-12 2014-03-11 Johnson Matthey Public Limited Company Catalysed substrate monolith
US9259684B2 (en) 2011-12-12 2016-02-16 Johnson Matthey Public Limited Company Exhaust system for a lean-burn internal combustion engine including SCR catalyst
US9333461B2 (en) 2011-12-12 2016-05-10 Johnson Matthey Public Limited Company Substrate monolith comprising SCR catalyst

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102018128739A1 (en) * 2018-11-15 2020-05-20 Dürr Systems Ag Emission control system and method and data processing system for monitoring at least one emission control system

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4201161A (en) * 1977-10-17 1980-05-06 Hitachi, Ltd. Control system for internal combustion engine
US5370101A (en) * 1993-10-04 1994-12-06 Ford Motor Company Fuel controller with oxygen sensor monitoring and offset correction
US5503134A (en) * 1993-10-04 1996-04-02 Ford Motor Company Fuel controller with air/fuel transient compensation
US5893039A (en) * 1997-04-14 1999-04-06 Precision Combustion, Inc. Catalytic method
US6854262B2 (en) * 2001-03-19 2005-02-15 Hitachi Unisia Automotive, Ltd. Air-fuel ratio control apparatus of internal combustion engine and method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4201161A (en) * 1977-10-17 1980-05-06 Hitachi, Ltd. Control system for internal combustion engine
US5370101A (en) * 1993-10-04 1994-12-06 Ford Motor Company Fuel controller with oxygen sensor monitoring and offset correction
US5503134A (en) * 1993-10-04 1996-04-02 Ford Motor Company Fuel controller with air/fuel transient compensation
US5893039A (en) * 1997-04-14 1999-04-06 Precision Combustion, Inc. Catalytic method
US6854262B2 (en) * 2001-03-19 2005-02-15 Hitachi Unisia Automotive, Ltd. Air-fuel ratio control apparatus of internal combustion engine and method thereof

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8137648B2 (en) * 2010-10-12 2012-03-20 Ford Global Technologies, Llc Diesel engine exhaust treatment system and method including a platinum group metal trapping device
US20110138777A1 (en) * 2010-10-12 2011-06-16 Hungwen Jen Diesel engine exhaust treatment system and method including a platinum group metal trapping device
US9005559B2 (en) 2011-10-06 2015-04-14 Johnson Matthey Public Limited Company Oxidation catalyst for internal combustion engine exhaust gas treatment
US8652429B2 (en) 2011-10-06 2014-02-18 Johnson Matthey Public Limited Company Oxidation catalyst for internal combustion engine exhaust gas treatment
US9868115B2 (en) 2011-10-06 2018-01-16 Johnson Matthey Public Limited Company Oxidation catalyst for internal combustion engine exhaust gas treatment
US8668891B2 (en) 2011-12-12 2014-03-11 Johnson Matthey Public Limited Company Exhaust system for a lean-burn IC engine comprising a PGM component and a SCR catalyst
US8986635B2 (en) 2011-12-12 2015-03-24 Johnson Matthey Public Limited Company Exhaust system for a lean-burn IC engine comprising a PGM component and a SCR catalyst
US9046022B2 (en) 2011-12-12 2015-06-02 Johnson Matthey Public Limited Company Catalysed substrate monolith
US20150238934A1 (en) * 2011-12-12 2015-08-27 Johnson Matthey Public Limited Company Catalysed substrate monolith
US9259684B2 (en) 2011-12-12 2016-02-16 Johnson Matthey Public Limited Company Exhaust system for a lean-burn internal combustion engine including SCR catalyst
US9333461B2 (en) 2011-12-12 2016-05-10 Johnson Matthey Public Limited Company Substrate monolith comprising SCR catalyst
US9597661B2 (en) * 2011-12-12 2017-03-21 Johnson Matthey Public Limited Company Catalysed substrate monolith
US8667785B2 (en) 2011-12-12 2014-03-11 Johnson Matthey Public Limited Company Catalysed substrate monolith
EP2790826B1 (en) 2011-12-12 2019-08-21 Johnson Matthey Public Limited Company Substrate monolith comprising scr catalyst

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Publication number Publication date
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Legal Events

Date Code Title Description
AS Assignment

Owner name: PRECISION COMBUSTION, INC., CONNECTICUT

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:PFEFFERLE, WILLIAM C.;REEL/FRAME:020401/0832

Effective date: 20080103

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION