WO1993002279A1 - Systeme d'echappement pour un moteur - Google Patents

Systeme d'echappement pour un moteur Download PDF

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Publication number
WO1993002279A1
WO1993002279A1 PCT/GB1992/001326 GB9201326W WO9302279A1 WO 1993002279 A1 WO1993002279 A1 WO 1993002279A1 GB 9201326 W GB9201326 W GB 9201326W WO 9302279 A1 WO9302279 A1 WO 9302279A1
Authority
WO
WIPO (PCT)
Prior art keywords
air
igniter
exhaust
gases
engine
Prior art date
Application number
PCT/GB1992/001326
Other languages
English (en)
Inventor
Thomas Tsoi-Hei Ma
Original Assignee
Ford Motor Company Limited
Ford Werke A.G.
Ford France S.A.
Ford Motor Company
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 Ford Motor Company Limited, Ford Werke A.G., Ford France S.A., Ford Motor Company filed Critical Ford Motor Company Limited
Publication of WO1993002279A1 publication Critical patent/WO1993002279A1/fr

Links

Classifications

    • 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
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/30—Arrangements for supply of additional air
    • F01N3/32—Arrangements for supply of additional air using air pump
    • 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
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/38—Arrangements for igniting
    • 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 relates to an afterburner for heating the exhaust gases of an internal combustion engine.
  • a system for purifying engine exhaust without the use of a catalytic converter, in which instead of a heated filament, a continuously operated spark plug is used in an attempt to complete the combustion of the exhaust gases in the presence of moisture-laden additional air drawn into a chamber in the exhaust system.
  • the mixture of air and carbon monoxide proved particularly difficult to ignite reliably.
  • the proposal in the MIRA pape requires thorough mixing of the fuel and air before it reaches the heated filament.
  • the latter is placed in a compartment at the front end of a silencer into which the air and exhaust gas mixture enters through a perforated plate.
  • the plate does not have any perforations in line with the filament to prevent the flame from being blown out.
  • the difficulty with such a construction is that there is only a narrow range of mixture strengths in which the mixture is ignitable and the air must be accurately matched to the carbon monoxide content if the mixture is to be ignited.
  • the present Applicant proposed in co-pending PCT Application PCT/GB 92/01035 to use an afterburner as a source of heat to reduce the light-off time of a catalytic converter.
  • the afterburner is used predominantly during cold starting and the primary purpose of the afterburner is not to reduce emissions (though this is a highly desirable side effect) but to generate heat to allow the catalytic converter to reach its light off temperature as quickly as possible and enable it to cope with the emissions.
  • This proposal requires air and combustible gases emanating from the engine to be ignited within the exhaust pipe and faces the same problem of how the additional air can be accurately metered to create a readily ignitable mixture.
  • the present invention seeks to provide an afterburner which renders the overall ratio of oxygen to combustible gases less critical so as to enable the mixture within the engine exhaust system to be ignited reliably.
  • an exhaust system for an internal combustion engine comprising an exhaust pipe for the gases emitted from the combustion chambers of the engine, air supply means for introducing additional air under pressure into the exhaust pipe, and an igniter for igniting the gaseous mixture consisting of the additional air and the gases from the engine combustion chambers, characterised in that the air supply means comprises at least one air injection orifice injecting a stream of air into the flow of exhaust gases and in that the igniter is arranged close to an air injection orifice in a region of the exhaust pipe in which the gaseous mixture is inhomogeneous.
  • the igniter is arranged in the region of turbulence at the interface between the injected air stream and the flow of exhaust gases.
  • the invention takes advantage of the fact that because of turbulence at the interface between the additional air and the exhaust gases, the mixture strength is constantly fluctuating within wide limits and if a rapid fire spark plug is used as an igniter there is a high probability of a spark finding an ignitable mixture within a short time of the afterburner being turned on.
  • the igniter is operated prior to commencement of the additional air injection whereby the turbulent interface at the front of the additional air flow traverses the region of the igniter while the latter is in operation.
  • Figure 1 is a section through part of an exhaust system having an afterburner with a single injection orifice
  • Figure 2 is a section similar to that of Figure 1 showing an exhaust system with several orifices distributed about the circumference of the exhaust pipe.
  • a section of exhaust pipe 10 is connected at one end to the engine to receive a flow of exhaust gases as represented by the arrows 12.
  • the gases leaving the engine either naturally or because of deliberate over fuelling, have a surplus of combustible gases, in particular carbon monoxide and hydrogen.
  • the section of the exhaust pipe 10 includes an afterburner which uses the surplus of combustible gases as fuel to generate heat.
  • the heated gases then leave the section of the exhaust pipe 10 along the direction of the arrows 26 and flow towards an item to be heated such as a catalytic converter of a petrol engine, the filter trap of a diesel engine or a heat exchanger for heating the passenger compartment.
  • the afterburner comprises an air supply line 14 connected to a single injection nozzle 16.
  • the supply line 14 receives ambient air, represented by the arrow 28, from an air pump (not shown), which may be electrically driven or mechanically driven by the engine.
  • a spark igniter 18 is arranged near the injection nozzle 16 and is formed of a high tension electrode 18a shielded from an earth electrode 18c and the exhaust pipe 10 by means of a ceramic insulator 18b.
  • the igniter 18 is connected to an oscillator circuit which rapidly fires a spark across the spark gap between the electrodes 18a and 18c, for example at the rate of fifty sparks per second.
  • the air from the injection nozzle 16 forms an expanding jet which fans out from the nozzle 16.
  • the vortex arrows 22 which causes the air to mix with, or diffuse into, the exhaust gases.
  • This region of highly inhomogeneous mixture will have a combustible gases to air ratio which fluctuates constantly within wide limits. Provided the combustible gases content of the exhaust gases is sufficiently high, there is bound to be at some time in this inhomogeneous region a readily ignitable mixture.
  • this jet of air injected into a stream containing combustible gases is analogous but complimentary to a conventional gas burner, in which a jet of combustible gas is injected into ambient air or an air stream and ignited.
  • a conventional burner combustion cannot take place within the fuel jet as there is no oxygen, nor can it take place in the ambient air stream where there is no fuel. Instead, the burning takes place at the interface between the two gas streams, where there is intense mixing.
  • all the burning takes places at the boundary of the injected air stream giving the classic shape of a flame.
  • the inner cone emanating from the nozzle 16 contains air only and is cold.
  • o may shield the igniter from the exhaust gas flow by means of a baffle, one may introduce swirl to enhance mixing at the boundary of the air jet or one may- include small obsTLT etions to the gas flow within the flame in order to enhance turbulence and hold the flame.
  • the flame should preferably spread over the entire cross section of the exhaust pipe as illustrated and in the embodiment of Figure 1 this is achieved using a single injection nozzle. If, owing to the diameter of the exhaust pipe or the maximum exhaust gas flow rate at which after- burning is required, a single injection nozzle does not suffice for the flame to spread over the entire cross section of the exhaust pipe then multiple injection orifices may be used as shown in Figure 2.
  • the air represented by the arrow 28 is pumped into a gallery 30 which surrounds the exhaust pipe 10 and orifices 32 are distributed around the exhaust pipe for injection of air into the stream of exhaust gases.
  • the interface 20 between the two gas streams in this case, extends from the surface of the pipe inwards towards the centre and the igniter 18 is arranged in the vicinity of this interface.
  • One igniter 18 still suffices in this case, located near one of the orifices 32 but more than one igniter may be provided if preferred.
  • the igniter illustrated is a spark igniter but it is alternatively possible to employ a heated filament or even a catalytic element.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Gas After Treatment (AREA)

Abstract

Système d'échappement pour un moteur thermique comprenant un tuyau d'échappement (10) pour les gaz provenant des chambres d'explosion du moteur, une alimentation en air (14) servant à introduire de l'air supplémentaire (28) sous pression dans le tuyau d'échappement (10), et un système d'allumage (18) destiné à enflammer le mélange gazeux constitué d'air supplémentaire et des gaz issus des chambres d'explosion du moteur. L'alimentation en air (14) comprend au moins un orifice d'injection (16) pour l'air qui permet d'injecter un flux d'air dans l'écoulement des gaz d'échappement (12), et le système d'allumage (18) est prévu à proximité de l'orifice d'injection (16) pour l'air dans une zone du tuyau d'échappement dans laquelle le mélange gazeux n'est pas homogène.
PCT/GB1992/001326 1991-07-19 1992-07-20 Systeme d'echappement pour un moteur WO1993002279A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9115628.1 1991-07-19
GB9115628A GB2257642A (en) 1991-07-19 1991-07-19 Engine exhaust system

Publications (1)

Publication Number Publication Date
WO1993002279A1 true WO1993002279A1 (fr) 1993-02-04

Family

ID=10698639

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1992/001326 WO1993002279A1 (fr) 1991-07-19 1992-07-20 Systeme d'echappement pour un moteur

Country Status (2)

Country Link
GB (1) GB2257642A (fr)
WO (1) WO1993002279A1 (fr)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1279334A (fr) * 1960-11-07 1961-12-22 Fr D Oxycatalyse Soc Procédé et dispositif permettant l'épuration des gaz d'échappement de moteurs à essence pendant la période de démarrage à froid de ces moteurs
US3203168A (en) * 1962-05-21 1965-08-31 Oxy Catalyst Inc Method and apparatus for improving the purification of exhaust gases from an internal combustion engine
US3263412A (en) * 1962-12-28 1966-08-02 William R Stroemer Method and means for eliminating smog
GB1200441A (en) * 1968-10-17 1970-07-29 Fur Luftverbesserung Ag Apparatus for after-burning exhaust gases from internal combustion engines
DE2031299A1 (de) * 1969-06-25 1971-01-14 Appca, Ine , Springfield, Va (VStA) Anordnung zur Steuerung der Emission eines Verbrennungsmotors
US3973916A (en) * 1974-04-01 1976-08-10 Shelton Everett E Emissions control system for an automotive vehicle or the like
GB2228072A (en) * 1989-02-10 1990-08-15 Sviluppo Materiali Spa Device for removal of particulates from exhausts and flue gases

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2053446B (en) * 1979-07-10 1983-04-07 Brown W R Exhaust gas anti-pollution control

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1279334A (fr) * 1960-11-07 1961-12-22 Fr D Oxycatalyse Soc Procédé et dispositif permettant l'épuration des gaz d'échappement de moteurs à essence pendant la période de démarrage à froid de ces moteurs
US3203168A (en) * 1962-05-21 1965-08-31 Oxy Catalyst Inc Method and apparatus for improving the purification of exhaust gases from an internal combustion engine
US3263412A (en) * 1962-12-28 1966-08-02 William R Stroemer Method and means for eliminating smog
GB1200441A (en) * 1968-10-17 1970-07-29 Fur Luftverbesserung Ag Apparatus for after-burning exhaust gases from internal combustion engines
DE2031299A1 (de) * 1969-06-25 1971-01-14 Appca, Ine , Springfield, Va (VStA) Anordnung zur Steuerung der Emission eines Verbrennungsmotors
US3973916A (en) * 1974-04-01 1976-08-10 Shelton Everett E Emissions control system for an automotive vehicle or the like
GB2228072A (en) * 1989-02-10 1990-08-15 Sviluppo Materiali Spa Device for removal of particulates from exhausts and flue gases

Also Published As

Publication number Publication date
GB2257642A (en) 1993-01-20
GB9115628D0 (en) 1991-09-04

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