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WO2009058056A1 - Moteur à combustion interne avec recirculation des gaz d'échappement - Google Patents

Moteur à combustion interne avec recirculation des gaz d'échappement Download PDF

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Publication number
WO2009058056A1
WO2009058056A1 PCT/SE2007/000971 SE2007000971W WO2009058056A1 WO 2009058056 A1 WO2009058056 A1 WO 2009058056A1 SE 2007000971 W SE2007000971 W SE 2007000971W WO 2009058056 A1 WO2009058056 A1 WO 2009058056A1
Authority
WO
WIPO (PCT)
Prior art keywords
engine
outlet
exhaust gases
intake
compressor
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.)
Ceased
Application number
PCT/SE2007/000971
Other languages
English (en)
Inventor
Per Larsson
Kent Giselmo
Martin Bauer
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.)
Volvo Truck Corp
Original Assignee
Volvo Lastvagnar AB
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 Volvo Lastvagnar AB filed Critical Volvo Lastvagnar AB
Priority to PCT/SE2007/000971 priority Critical patent/WO2009058056A1/fr
Publication of WO2009058056A1 publication Critical patent/WO2009058056A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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
    • F01N5/00—Exhaust or silencing apparatus combined or associated with devices profiting by exhaust energy
    • F01N5/04—Exhaust or silencing apparatus combined or associated with devices profiting by exhaust energy the devices using kinetic energy
    • 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
    • F02B29/00—Engines characterised by provision for charging or scavenging not provided for in groups F02B25/00, F02B27/00 or F02B33/00 - F02B39/00; Details thereof
    • F02B29/04—Cooling of air intake supply
    • F02B29/0406—Layout of the intake air cooling or coolant circuit
    • 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
    • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
    • F02B37/12—Control of the pumps
    • F02B37/16—Control of the pumps by bypassing charging air
    • 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
    • F02M26/02—EGR systems specially adapted for supercharged engines
    • F02M26/04—EGR systems specially adapted for supercharged engines with a single turbocharger
    • F02M26/05—High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
    • 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
    • F02M26/22—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories with coolers in the recirculation passage
    • F02M26/23—Layout, e.g. schematics
    • F02M26/28—Layout, e.g. schematics with liquid-cooled heat exchangers
    • 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 internal combustion engine with exhaust gas recirculation according to the preamble of the appended claim 1.
  • the invention is particularly related to reducing harmful emissions from a diesel engine being provided with a system for recirculation of exhaust gases to the intake of the engine, a so called EGR system (Exhaust Gas Recirculation).
  • EGR system Exhaust Gas Recirculation
  • the invention also relates to a method for a combustion engine according to the preamble of the appended claim 5.
  • the exhaust gases are normally purified by means of a catalytic converter located in the exhaust system. Because a diesel engine is operated with an air surplus, however, the three- way catalyst cannot be used for reduction of NO x compounds from a diesel engine.
  • NO x compounds generated in a diesel engine is principally exponentially proportional to the temperature inside the combustion chamber, and, by using an EGR system, the local temperature during combustion can be lowered by dilution with exhaust gases (CO 2 and H 2 O). This in turn leads to less creation of NO x .
  • a diesel engine may be provided with an EGR system by connecting a separate line between the ordinary exhaust outlet of the engine and a point close to the fresh air intake of the engine.
  • a controllable valve is arranged, this valve further being connected to a control unit.
  • the control unit will determine the degree of opening of the valve, i.e. the amount of EGR gases to be recirculated to the engine air intake. A certain amount of EGR gases will then be fed from the engine exhaust side to its intake side, through the exhaust side pressure normally being higher than the intake side pressure, thus creating a natural "propulsion pressure" for the EGR gases.
  • this problem can be solved by providing the turbocharger with variable turbine geometry.
  • One arrangement using this solution is shown in the patent document JP-08270454 A, disclosing a diesel engine having a turbocharger in turn comprising adjustable guide vanes, which, depending on the engine operating conditions, ican be adjusted to a certain position by means of a control unit. In this way, a sufficiently high pressure can be created on the engine exhaust side, whereby a required amount of EGR gases can be recirculated to the intake side.
  • the object of the present invention is to provide an improved arrangement for a combustion engine, particularly a diesel engine being equipped with an
  • Fig. 1 depicts in a schematical form an example embodiment according to the present invention.
  • Fig. 2 depicts a diagram of the Exhaust Recirculation Valve (EGR) valve area as a function of Discharge Recirculation Valve (DRV) area @ 850rpm and 50% load according to an example embodiment of the present invention.
  • Fig. 3 depicts a BSNO x (Break Specific Oxides of Nitrogen) (engine out) as a function of DRV area @ 850rpm and 50% load according to an example embodiment of the present invention.
  • EGR Exhaust Recirculation Valve
  • DRV Discharge Recirculation Valve
  • Fig. 3 depicts a BSNO x (Break Specific Oxides of Nitrogen) (engine out) as a function of DRV area @ 850rpm and 50% load according to an example embodiment of the present invention.
  • Fig. 4 depicts a pressure drop engine as a function of DRV area @ 850rpm and 50% load according to an example embodiment of the present invention.
  • the diesel engine 1 is intended for use in a load-carrying vehicle, and comprises six cylinders 2.
  • the invention is however not limited to any specific number of cylinders or any specific cylinder configuration.
  • the engine 1 is equipped with an intake manifold 3, to which air is fed from the atmosphere via an intake conduit 4. The input air is then divided between the various cylinders 2.
  • fuel is supplied to the cylinders 2 by a corresponding number of fuel injection devices 5 that are each connected to a central control unit 6 via an electrical connection 7.
  • the control unit 6, which is preferably computer based, is in a known manner operative to control each fuel injection device 5 so as to supply, in each instant, an appropriate fuel/air mixture to the engine 1.
  • the control unit 6 is operative to control the respective injection device 5 in such a way that the fuel/air mixture supplied to the engine 1 will be adapted, in each instant, to the current operating conditions.
  • the fuel supply is hereby obtained in a generally known manner, i.e. in dependence of a multitude of parameters representative of the operating conditions of the engine 1 and the vehicle in question.
  • the control can be performed depending on the present throttle position and the rotational speed and load of the engine 1.
  • Each cylinder 2 is provided with an exhaust outlet 8. Together, the exhaust outlets 8 converge into an exhaust manifold 9, continuing into an exhaust pipe 10.
  • This exhaust pipe runs via a turbocharger unit 11 , which as such is substantially conventional.
  • the turbocharger unit 11 comprises a means for absorbing energy from the exhaust gases in the form of a turbine
  • the exhaust outlets 8 join into a single exhaust pipe 10 (known as a "single inlet")
  • the exhaust outlets may be grouped into two groups, making the exhaust duct consist of two pipes leading to the turbine 12 (known as a "twin inlet” or a “double inlet”).
  • the turbine 12 is arranged on a shaft 13, on which a compressor 14 is likewise arranged.
  • the energy absorbed from the exhaust flow by the turbine 12 is in this way transferred to the compressor 14, which functions to compress the in-flowing air to the intake conduit 4 of the engine 1. In this manner, an increased fuel amount may be fed to the engine 1 , whereby its power output can be increased.
  • the engine 1 is further equipped with an arrangement for recirculation of a certain amount of exhaust gases to the intake side of the engine 1. According to what was discussed in the introduction, an EGR system
  • EGR line 15 is therefore connected to the exhaust pipe 9, at a point upstream of the turbine 12.
  • the EGR line 15 debouches in the intake conduit 4, at a point upstream of the intake manifold 3 of the engine 1.
  • a controllable valve is also connected to the exhaust pipe 9, at a point upstream of the turbine 12.
  • EGR valve 16 is arranged, connected to the control unit 6 via a further connection 17. According to what will be described in greater detail below, the control unit 6 is operative, in dependence of the present operating conditions, to adjust the valve 16 to a dosed, open or partially open position. Depending on the position of the valve 16, a corresponding amount of exhaust gases will thus be recirculated to the intake manifold 3 via the EGR line. Through the recirculation of these EGR gases to the intake manifold 3, a temperature reduction during the combustion is achieved in the respective cylinder 2, whereby the NO x generation in the cylinder 2 is reduced.
  • the EGR line 15 is provided with a cooler 18 functioning to cool the EGR gases recirculated to the intake manifold 3.
  • the cooler 18 includes a loop 19 through which a suitable coolant is circulated.
  • this coolant is the ordinary coolant for the engine 1, but air may also be used for this cooling or a separate cooler cooled by a liquid medium.
  • the EGR gases can be cooled, which further contributes to reducing the generated amount of NO x compounds.
  • An additional cooler may be provided in the
  • EGR line 15 e.g. a so called pre-cooler.
  • the intake conduit 4 is also equipped with a cooler 20, (known as an "intercooler"), which is used for cooling the compressed air supplied by the compressor 14. This also contributes to a reduction of the amount of NO x compounds generated in the engine 1.
  • the intake air cooler 20 may be arranged for cooling by air or a coolant, which is schematically indicated at the reference number 21.
  • a second turbine 22 is used for absorbing energy from the exhaust gases.
  • the exhaust gases leaving the engine 1 and being passed through the first turbine 12 are thus also fed through the second turbine 22, which is then brought to rotate.
  • the second turbine 22 is rotatably arranged on a further shaft 23.
  • the exhaust gases are conducted out to the atmosphere, for instance by way of a silencer and/or an after treatment system (not shown).
  • the second turbine 22 is connected to the output crankshaft 24 of the engine 1 , via a power transmission 25, not shown in any detail, which in the figure is schematically indicated by a dashed line.
  • the power transmission 25 is preferably of a mechanical type including a gear transmission connecting the shaft 23 to the crankshaft 24.
  • the power transmission is moreover provided with a gear reduction for conversion of the rotational speed of the second turbine 22 to a rotational speed suitable for the crankshaft 24. In this manner, power is transferred between the second turbine 22 and the crankshaft 24, i.e. a certain amount of energy in the combustion gases can be regained from the exhaust flow and be used as additional power to the crankshaft 24.
  • a system for an engine having a turbocharger unit arranged for extraction of a certain amount of energy from the exhaust gases and feeding this energy back to the engine crankshaft is normally called a "turbo compound" system.
  • a pressure is achieved, during operation of the engine 1 , on the exhaust side of the engine 1 , which is higher than the pressure on its intake side.
  • a sufficient propulsion pressure is obtained for recirculation of EGR gases to the intake manifold 3, without deterioration of the efficiency of the engine 1.
  • part of the energy contained in the exhaust gases is utilised as additional power to the crankshaft 24 instead of being conducted out into the atmosphere and thus being lost.
  • a recirculation conduit 26 is provided between the outlet and the inlet of the compressor 14.
  • a valve 27 is provided for controlling flow through the recirculation conduit 26.
  • valve 27 is controllable by means of the control unit 6 via the connection 17, either step by step or continuously variable between its end positions.
  • the invention includes controllable valves 16, 27, in connection with the control unit 6.
  • the valves 16, 27 are used in such a manner that a certain amount of exhaust gases from the respective exhaust outlets 8 of the engine 1 are passed back to the intake manifold 3.
  • the valves 16, 27 consist of electronically controlled valves, which, by means of the control unit 6, can be controlled continuously between an open and a closed position.
  • DVR Discharge Recirculation Valve
  • control unit 6 is arranged for determination of the rotational speed and load (torque) of the engine, and for calculation, depending on these parameters, of the desirable amount of EGR gases to be recirculated to the intake manifold.
  • This amount of EGR gases is preferably determined in the control unit 6 by using a stored table giving the required amount of EGR gases as a function of the speed and load.
  • the valves 16 and 27 are adjusted to a corresponding position through a signal from the control unit 6.
  • the recirculated amount has to be adapted concerning predetermined limit levels for soot and carbon monoxide released with the exhaust gases.
  • the EGR recirculation reduces the amount of air available at the engine intake, it must be ascertained that the amount of air is sufficient with regard to said limit levels.
  • valves 16 and 27 By virtue of the valves 16 and 27 discussed above, that can be continuously adjusted to a desired position, a very large variation of the aperture area of the valve 16 is allowed between different extremes in the operating conditions of the engine 1. For the arrangement according to the embodiment, where energy is transferred from the second turbine 22 to the crankshaft 24, this large variation is required, as the pressure differential between the exhaust side and the intake side varies to a high degree as a function of the engine load. As a comparison it can be mentioned that this pressure differential varies considerably more than by previously known systems comprising turbocharger units with variable turbine geometry.
  • a correct flow of EGR gases can be ascertained, which is substantially independent of the operating conditions of the engine 1.
  • control unit 6 may also be functional to control the valves 16, 27 in dependence of other parameters. For example, transients can be taken into account to avoid unwanted puffs of smoke in the engine 1 exhausts.
  • the flow area relation of the DRV 27 and the EGR valve 16 may for example be regulated to a proportion between 1 :80 and 1 :2. In another example embodiment the flow area relation of the DRV 27 and the EGR valve 16 may for instance be regulated to a proportion between 0-1.
  • FIG. 2 illustrates the EGR valve 16 area as a function of DRV (Discharge Recirculation Valve) 27 area @ 850rpm and 50% load of the engine. From the diagram in figure 2 it is illustrated the necessary opening area of EGR valve 16 at different areas of the DRV 27. In case DRV 27 is closed it is necessary in this example embodiment to open the EGR valve 16 with 15 cm 2 , which is its maximum opening valve area in this embodiment. As is illustrated from figure 2, the more we open up the DRV 27 the more the EGR valve 16 may be closed with constant NO x , see figure 3. This is true up to opening area 1 cm2 for the DRV 27, going beyond 1 cm2 of the DRV 27 the NO x is decreased.
  • DRV discharge Recirculation Valve

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Exhaust-Gas Circulating Devices (AREA)
  • Supercharger (AREA)

Abstract

L'invention porte sur un moteur à combustion interne (1) ayant au moins un cylindre (2), une admission (3, 4) pour l'alimentation d'air, un orifice de sortie d'échappement (9, 10) pour décharger des gaz d'échappement, et une autre conduite (15) pour la recirculation des gaz d'échappement dudit orifice de sortie (9, 10) à ladite admission (3, 4) en vue de réduire les émissions nocives provenant du moteur (1). Selon l'invention, une soupape commandable (16) est disposée dans ladite autre conduite (15). Une unité de turbocompresseur (11) comprend des premiers moyens (12) pour absorber l'énergie des gaz d'échappement et un compresseur (14) avec un orifice d'entrée et un orifice de sortie pour comprimer de l'air vers ladite admission (3,4) et des seconds moyens (22) pour absorber l'énergie des gaz d'échappement, disposés en aval desdits premiers moyens (12), pour créer dans ledit orifice de sortie (9, 10) une pression qui dépasse la pression dans ladite admission (3, 4). Une transmission de puissance (25) est disposée entre lesdits seconds moyens (22) et un vilebrequin (24) associé au moteur (1). Un conduit de recirculation d'air de suralimentation (26) est disposé entre l'orifice de sortie du compresseur (14) et l'orifice d'entrée du compresseur, et une soupape (27) régule l'écoulement à travers le conduit de recirculation d'air de suralimentation (26).
PCT/SE2007/000971 2007-11-01 2007-11-01 Moteur à combustion interne avec recirculation des gaz d'échappement Ceased WO2009058056A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/SE2007/000971 WO2009058056A1 (fr) 2007-11-01 2007-11-01 Moteur à combustion interne avec recirculation des gaz d'échappement

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/SE2007/000971 WO2009058056A1 (fr) 2007-11-01 2007-11-01 Moteur à combustion interne avec recirculation des gaz d'échappement

Publications (1)

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WO2009058056A1 true WO2009058056A1 (fr) 2009-05-07

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999031373A1 (fr) * 1997-12-03 1999-06-24 Volvo Lastvagnar Ab Conception d'un moteur a combustion
US6945240B2 (en) * 2000-05-24 2005-09-20 Nissan Diesel Motor Co., Ltd. Device and method for exhaust gas circulation of internal combustion engine
US20060185363A1 (en) * 2005-02-21 2006-08-24 Gustafson Richard J Boost wastegate device for EGR assist

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999031373A1 (fr) * 1997-12-03 1999-06-24 Volvo Lastvagnar Ab Conception d'un moteur a combustion
US6945240B2 (en) * 2000-05-24 2005-09-20 Nissan Diesel Motor Co., Ltd. Device and method for exhaust gas circulation of internal combustion engine
US20060185363A1 (en) * 2005-02-21 2006-08-24 Gustafson Richard J Boost wastegate device for EGR assist

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