EP0704021A1 - Remise en circulation des gaz d'echappement dans des moteurs deux temps a combustion interne - Google Patents

Remise en circulation des gaz d'echappement dans des moteurs deux temps a combustion interne

Info

Publication number
EP0704021A1
EP0704021A1 EP94916841A EP94916841A EP0704021A1 EP 0704021 A1 EP0704021 A1 EP 0704021A1 EP 94916841 A EP94916841 A EP 94916841A EP 94916841 A EP94916841 A EP 94916841A EP 0704021 A1 EP0704021 A1 EP 0704021A1
Authority
EP
European Patent Office
Prior art keywords
exhaust gas
crankcase
engine
induction system
combination
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.)
Withdrawn
Application number
EP94916841A
Other languages
German (de)
English (en)
Other versions
EP0704021A4 (fr
Inventor
David Richard Worth
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.)
Orbital Engine Co Pty Ltd
Original Assignee
Orbital Engine Co Pty Ltd
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 Orbital Engine Co Pty Ltd filed Critical Orbital Engine Co Pty Ltd
Publication of EP0704021A1 publication Critical patent/EP0704021A1/fr
Publication of EP0704021A4 publication Critical patent/EP0704021A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D21/00—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas
    • F02D21/06—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas peculiar to engines having other non-fuel gas added to combustion air
    • F02D21/08—Controlling engines characterised by their being supplied with non-airborne oxygen or other non-fuel gas peculiar to engines having other non-fuel gas added to combustion air the other gas being the exhaust gas of engine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M25/00—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture
    • F02M25/06—Engine-pertinent apparatus for adding non-fuel substances or small quantities of secondary fuel to combustion-air, main fuel or fuel-air mixture adding lubricant vapours
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
    • F02M26/17—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories in relation to the intake system
    • F02M26/20—Feeding recirculated exhaust gases directly into the combustion chambers or into the intake runners
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
    • F02M26/40—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with timing means in the recirculation passage, e.g. cyclically operating valves or regenerators; with arrangements involving pressure pulsations
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
    • F02M26/41—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories characterised by the arrangement of the recirculation passage in relation to the engine, e.g. to cylinder heads, liners, spark plugs or manifolds; characterised by the arrangement of the recirculation passage in relation to specially adapted combustion chambers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/02—Engines characterised by their cycles, e.g. six-stroke
    • F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
    • F02B2075/025—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle two

Definitions

  • the disclosed method of operating a two stroke cycle crankcase scavenged internal combustion engine comprises selectively delivering exhaust gas from a location downstream of the engine exhaust port directly into the engine crankcase to be delivered together with air in the crankcase to an engine combustion chamber, and controlling the quantity of exhaust gas delivered to the crankcase each engine cycle in accordance with engine operating conditions.
  • the admission of the exhaust gas to the crankcase is principally for the control of exhaust emissions, it is not necessary, and in some circumstances can be undesirable, to admit exhaust gas to the crankcase under all operating conditions. Accordingly, in the invention of this prior application, it is desirable to be selective in the introduction of the exhaust gas to the crankcase and also in controlling the rate of supply of exhaust gas.
  • This control of the exhaust gas supply to the engine can be achieved by an ECU managed control valve provided between the exhaust system of the engine and the engine crankcase to control the exhaust gas flow to the crankcase.
  • the ECU managing the control valve preferably receives inputs regarding engine operating conditions and in particular, engine load, speed and temperature conditions and from these inputs determines when exhaust gas is required to be introduced to the crankcase and the quantity thereof required.
  • control valve incorporates a position feedback means to indicate to the ECU the actual position of the valve to thereby permit comparison of the actual position thereof with the required position thereby enhancing the accuracy of the control of the rate of supply of exhaust gas to the crankcase.
  • the ECU can be programmed to determine the actual mass of exhaust gas delivered to the crankcase each cycle and to compare that mass with the required mass of exhaust gas for the existing engine operating conditions.
  • the mass of air and exhaust gas in the crankcase can be determined by measuring the temperature and pressure therein at a preset point in the engine cycle when the volume of the space in the crankcase is known.
  • the difference between this calculated gas mass and the mass of air entering the crankcase determined by, for example, an air flow sensor in the intake manifold, would give the mass of recirculated exhaust gas in the crankcase. Any correction required can then be effected by adjustment of the rate of supply of exhaust gas to the crankcase via the ECU controlled valve. Further, the accuracy of this measurement process can be checked by comparing the calculated air mass in the crankcase with the air mass as determined by the air flow sensor when no exhaust gas is present in the crankcase.
  • the present invention provides a method of operating a two stroke cycle crankcase scavenged internal combustion engine comprising selectively delivering exhaust gas from a location downstream of an engine exhaust port to a crankcase associated with at least one engine cylinder and into an induction system of the engine upstream of an entrance to the crankcase associated with at least one engine cylinder.
  • the means to deliver exhaust gas is arranged so that the exhaust gas is delivered to the induction system in the proximity of the conventional throttle valve, and preferably at or adjacent to the upstream side of the throttle valve and downstream of any air flow sensor in the induction system.
  • a control valve is provided in a line conveying the exhaust gas to the induction system and that valve is ECU controlled in response to inputs related to engine operating conditions such as load, speed, crankcase pressure, and temperature so that the supply of exhaust gas to the induction system can be terminated if desired and/or the rate of supply of exhaust gas varied.
  • a plenum chamber may be provided which communicates individually with the crankcase of each cylinder, with exhaust gas from one or more of the engine cylinders being provided to the plenum chamber.
  • exhaust gas from one or more of the engine cylinders being provided to the plenum chamber.
  • the exhaust gas for admission to the induction system may also be supplied from the same plenum chamber.
  • the port or ports may be convenient in some engine configurations to provide two or more such piston controlled ports to provide a relatively large flow area for the exhaust. gas into the crankcase.
  • the port or ports Preferably, the port or ports have the major dimension thereof in the circumferential direction of the cylinder to provide the maximum open port area during the restricted port open period. It has been found that the use of a piston controlled port to control the timing of admission of the exhaust gas results in improved equitable cylinder to cylinder distribution of the exhaust gas.
  • the exhaust gas can be taken from the exhaust system either upstream or downstream of the catalyst unit.
  • the method and apparatus as disclosed herein may be used exclusively to recycle combusted gas to the combustion chambers of an engine for the purposes of emission control or may be used in conjunction with other forms of exhaust gas recirculation such as, for example, those disclosed in the applicant's co-pending Patent Application No. PL 9163.
  • Figure 2 is a more detailed drawing of an alternative embodiment of an exhaust gas recirculation system
  • Figure 3 is a longitudinal sectional plan view of a portion of a three cylinder engine incorporating the exhaust gas recirculation system as shown in Figures 1 and 2.
  • Figure 1 there is illustrated diagrammatically a typical crankcase scavenged two stroke cycle engine having a cylinder 1 and a piston 2 connected in the conventional manner to a crankshaft (not shown) located in a crankcase 3.
  • An air induction passage 4 communicates with the crankcase 3 via a reed valve assembly 11 in the conventional manner, and conventional transfer porting and passages are provided in the piston 2 and cylinder 1 for the transfer of air or an air/fuel mixture from the crankcase 3 to a combustion chamber 12 above the piston 2.
  • An exhaust port 5 is provided in the wall of the cylinder 1 which communicates the combustion chamber 12 with the exhaust pipe 14 when the piston 2 has moved downwardly in the cylinder 1 a distance sufficient to uncover the exhaust port 5.
  • the exhaust pipe 14 conveys exhaust gases to a suitable discharge location.
  • a bypass passage 15 communicates with the exhaust pipe 14 at a junction 6 to convey exhaust gas from the exhaust pipe 14 to the exhaust gas recirculation (EGR) plenum chamber 7 and/or an air induction system 20 of the engine.
  • a valve 8, in the bypass passage 15, is operable to control the delivery of the exhaust gas from the exhaust pipe 14 to the EGR chamber 7, which is communicable with the crankcase 3 via a reed valve assembly 9.
  • the bypass passage 15 is preferably located to communicate with the exhaust pipe 14 at a high pressure area such as upstream of a main catalyst (not shown) in the exhaust pipe 14. Also, the valve 8 is preferably located close to the crankcase 3 to reduce lag in the response of the engine to adjustment of the valve 8.
  • the air induction system 20 incorporates a conventional throttle valve 21 to control the rate of air supply to the engine, that is to all cylinders 1 of the engine.
  • the passage 22 communicates with the bypass passage 15 upstream of the valve 8 and with the air induction system 20 immediately upstream of the throttle valve 21.
  • a valve 23 controls the supply of exhaust gas to the air induction system 20.
  • the amount of exhaust gas admitted to the crankcase 3 and the air induction system 20 can be controlled by the valves 8 and 23 respectively and, subject to engine operating conditions, the control valves 8 and 23 may be open, closed, or occupy any intermediate position therebetween.
  • control valves 8 and 23 are managed by an ECU 17 which receives input signals indicative of various operating conditions of the engine, and in accordance with a preset strategy, the quantity of exhaust gas admitted to the crankcase 3 and/or the air induction system 20 respectively per cylinder cycle is controlled.
  • This control is conveniently achieved by way of a look-up map stored in the ECU.
  • FIG. 2 of the drawings there is shown a partial cross section of a crankcase scavenged two stroke cycle engine with the crankcase and cylinder block in cross section and the cylinder head and injector equipment in full outline.
  • the piston, crankshaft and connecting rod are not shown in Figure 2.
  • the cylinder 30 as shown in
  • branch passage 39 Downstream of the catalyst elements 38, the exhaust pipe 37 communicates with a branch passage 39 which leads to a cavity 40 in the cylinder block.
  • the branch passage 39 communicates with the exhaust pipe 37 downstream of the exhaust catalyst elements 38.
  • branch passage 39 may alternatively communicate with the exhaust pipe 37 upstream of the catalyst elements 38 where, typically, the pressure of the exhaust gas is higher, the temperature is lower and the oxygen content therein is lower.
  • the preferred timing of the opening and closing of the EGR port 45 is within a range of 40° to 60° before and 40° to 60° after the top dead centre position of the piston in the respective cylinder 30. It will be appreciated that the communication between the crankcase 35 and the EGR port 45 may be determined by the location of an appropriate aperture in the skirt of the piston. This is common technology in relation to the control of the flow of gases through the transfer ports of two stroke cycle engines such as the transfer ports 33 and 34 as shown in Figure 2. Further, it is preferred that the port 45 is located on the side of the cylinder 30 against which the piston is thrust so as to effectively seal the port 45 when required.
  • the cavity 40 also communicates via the passage 46 with the air induction passage 47 through which air is drawn into the respective crankcases 35 of each cylinder 30.
  • the passage 46 delivers exhaust gas to the air induction passage 47 immediately upstream of the throttle valve 49 that controls the rate of air intake to the engine.
  • the passage 46 is provided with a valve element 50 which controls, in association with valve element 41 , the operation of which will be described hereunder, the quantity of exhaust gas supplied to the air induction passage 47.
  • Valve element 50 may be controlled in a similar manner as valve element 41.
  • the air induction passage 47 may connect directly with the exhaust pipe 37 or branch passage 39 and independently of the cavity 40.
  • An independent control valve may be provided in the air induction passage 47 of such an independent construction. This construction would enable exhaust gas to be supplied in a controlled manner to the crankcase 35 and the induction system 47 individually or in combination.
  • the solenoid unit 42 which controls the operation of the valve element 41 is under the control of a programmed ECU incorporating an appropriate look-up map.
  • the map is arranged so that the valve element 41 controlling the exhaust gas flow to the crankcase 35 and air induction passage 47 is ramped rapidly from closed to open once the fuelling rate increases above a selected level.
  • the solenoid unit 42 is typically provided with a valve element position sensor which provides feedback information to the
  • the ECU can be programmed to determine the mass of air entering each crankcase 35 and to determine the combined exhaust gas and air mass in the crankcase 35 at a point in the cycle of that engine cylinder 30.
  • the mass of air entering the crankcase 35 can be determined by the conventional hot wire air flow meter in the air induction passage 47, and the mass of air and exhaust gas can be determined by measuring the temperature and pressure in the crankcase 35 at a preset point in the engine cycle where the volume of the space in the crankcase 35 is known. From these two mass determinations the actual mass of exhaust gas can be determined and compared with the required amount of exhaust gas, thus determining if adjustment is required to be made to the rate of supply of the exhaust gas.
  • This method of determining the exhaust gas content within the crankcase 35 can be used in conjunction with other forms of control of EGR than that described herein.
  • engine operating parameters that can be controlled, in conjunction with the supply of exhaust gas to the crankcase 35 and air induction system 47, include advance of the ignition spark to improve stability, and the use of a back pressure valve in the exhaust system, downstream of the point of exhaust gas take-off to control the rate of exhaust gas available for supply to the combustion chamber.
  • the greater the back pressure in the exhaust system the greater the pressure and hence the rate of supply of exhaust gas for admission to the crankcase 35.
  • the exhaust gas to be delivered to the engine cylinder 30 can be passed through a heat exchanger or other cooling means prior to entry to the crankcase 35 in order to increase the density thereof whereby a greater mass of exhaust gas would then be available for delivery to the crankcase 35.
  • the branch passage 39 communicates with the exhaust pipe 37 downstream of the catalyst element 38. However, it may alternatively communicate with the exhaust pipe 37 upstream of the catalyst element where the pressure of the exhaust gas is higher and the temperature lower.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust-Gas Circulating Devices (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Abstract

Procédé de fonctionnement d'un moteur à combustion interne à carter-moteur balayé à deux temps selon lequel on envoie sélectivement les gaz d'échappement provenant d'un endroit (6) situé en aval d'une sortie d'échappement (5) du moteur dans un carter-moteur (7) associé à au moins un cylindre (1) du moteur et dans un système d'admission du moteur situé en amont d'une entrée (4) vers le carter-moteur. Un moteur équipé d'un système permettant d'utiliser ce procédé est également revendiqué.
EP94916841A 1993-06-02 1994-05-31 Remise en circulation des gaz d'echappement dans des moteurs deux temps a combustion interne Withdrawn EP0704021A4 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
AUPL9164/93 1993-06-02
AUPL916493 1993-06-02
PCT/AU1994/000288 WO1994028299A1 (fr) 1993-06-02 1994-05-31 Remise en circulation des gaz d'echappement dans des moteurs deux temps a combustion interne

Publications (2)

Publication Number Publication Date
EP0704021A1 true EP0704021A1 (fr) 1996-04-03
EP0704021A4 EP0704021A4 (fr) 1996-05-22

Family

ID=3776943

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94916841A Withdrawn EP0704021A4 (fr) 1993-06-02 1994-05-31 Remise en circulation des gaz d'echappement dans des moteurs deux temps a combustion interne

Country Status (8)

Country Link
EP (1) EP0704021A4 (fr)
JP (1) JPH09504848A (fr)
KR (1) KR960702056A (fr)
CN (1) CN1120362A (fr)
BR (1) BR9406493A (fr)
CA (1) CA2162037A1 (fr)
TW (1) TW289783B (fr)
WO (1) WO1994028299A1 (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TW273584B (fr) * 1993-01-04 1996-04-01 Orbital Engline Co Australia Pgy Ltd
AUPN118695A0 (en) 1995-02-16 1995-03-09 Orbital Engine Company (Australia) Proprietary Limited Improvements relating to internal combustion engines
AUPN567195A0 (en) * 1995-09-27 1995-10-19 Orbital Engine Company (Australia) Proprietary Limited Valve timing for four stroke internal combustion engines
DE102005057207B4 (de) * 2005-12-01 2011-07-21 Man Diesel & Turbo, Filial Af Man Diesel & Turbo Se, Tyskland Verbrennungsmotor sowie Verfahren zur Reduktion des NOx- Ausstoßes bei einem derartigen Motor
DK201000077U4 (da) * 2010-04-29 2012-05-25 Beco Consult Aps Lukkemekanisme for kasser og låg
CN102966429A (zh) * 2011-11-19 2013-03-13 摩尔动力(北京)技术股份有限公司 燃气二冲程发动机
US8935997B2 (en) 2013-03-15 2015-01-20 Electro-Motive Diesel, Inc. Engine and ventilation system for an engine
CN106762247B (zh) * 2015-11-19 2020-03-06 通用全球采购有限责任公司 基于曲柄箱压力进行排气再循环阀诊断的方法和系统

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2420034A1 (fr) * 1978-03-14 1979-10-12 Soubis Jean Pierre Perfectionnements a des moteurs deux temps ameliorant la combustion et permettant une reduction de la pollution
DE2946483A1 (de) * 1979-11-17 1981-05-27 Fichtel & Sachs Ag, 8720 Schweinfurt Brennkraftmaschine mit einer vorrichtung zur rueckfuehrung unverbrannter kraftstoffanteile

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
No further relevant documents disclosed *
See also references of WO9428299A1 *

Also Published As

Publication number Publication date
CA2162037A1 (fr) 1994-12-08
WO1994028299A1 (fr) 1994-12-08
JPH09504848A (ja) 1997-05-13
TW289783B (fr) 1996-11-01
EP0704021A4 (fr) 1996-05-22
CN1120362A (zh) 1996-04-10
BR9406493A (pt) 1996-01-09
KR960702056A (ko) 1996-03-28

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