Classifications

• • 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
  • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
  • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
  • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
  • F02B23/0672—Omega-piston bowl, i.e. the combustion space having a central projection pointing towards the cylinder head and the surrounding wall being inclined towards the cylinder center axis
• • 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
  • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
  • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
  • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
  • F02B23/0678—Unconventional, complex or non-rotationally symmetrical shapes of the combustion space, e.g. flower like, having special shapes related to the orientation of the fuel spray jets
  • F02B23/069—Unconventional, complex or non-rotationally symmetrical shapes of the combustion space, e.g. flower like, having special shapes related to the orientation of the fuel spray jets characterised by its eccentricity from the cylinder axis
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
  • F02F3/00—Pistons 
  • F02F3/26—Pistons  having combustion chamber in piston head
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
  • F02F3/00—Pistons 
  • F02F3/28—Other pistons with specially-shaped head
• • 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
  • F02B3/00—Engines characterised by air compression and subsequent fuel addition
  • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
• • 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 invention relates generally to the design of heat engines, in particular internal combustion engines and compression ignition engines.
• the object of the present invention is to propose an improved combustion chamber, which makes it possible in particular to reduce the emission level at the exhaust of nitrogen oxides and particles.
• the subject of the invention is a piston for an internal combustion engine, in particular for a diesel engine, comprising a body delimited laterally by a skirt adapted to cooperate with the walls of a cylinder of axis of revolution C in which the piston is adapted to slide along this axis C, said piston having a front face which comprises a central pin, a peripheral ring and a bowl of axis of revolution B which extends from the central pin to the peripheral ring to which it is connected at the level of a lip of thickness Ep, said bowl comprising substantially vertically above the lip, a profile torus, preferably in a cul-de-oven, of maximum radius Rt capable of guiding a fuel injected under the lip at the level of a reentrant zone R towards the central stud, remarkable in that the central stud has an upper slope of angle A1 and lower of A2 distinct angle,
• the piston comprises one or more of the following characteristics:
• the lower angle slope A1 taken from the axis of revolution B of the bowl in the geometric direction is between 69 ° and 84 ° and is preferably substantially equal to 72 °;
• the lower angle slope A2 taken from 3 'axis of revolution B of the bowl in the geometric direction is between 47 ° and 62 ° and is preferably substantially equal to 59 °;
• the bowl is off center, the axis of revolution B of the bowl being separate and placed at a distance from the axis of revolution C of the cylinder;
• the thickness Ep of the lip is between 3 mm and 5 mm and is preferably substantially equal to 4.5 mm;
• the lip is located at a distance De / 2 of the axis of revolution B of the bowl, the distance De being between 45mm and 48mm and is preferably substantially equal to 47mm;
• the torus is located at a distance Db / 2 of the axis of revolution B of the bowl, the distance Db is between 48mm and 51mm and preferably substantially equal to 49mm;
• the difference in distances, with respect to the axis of revolution B of the bowl, of the end of the crown De / 2 and of the end of the torus Db / 2 is substantially equal to 1 mm;
• the maximum depth P of the bowl is between 13 mm and 14.5 mm and is preferably substantially equal to 13.5 mm;
• the top of the stud located on the axis of revolution B of the bowl rises to a height less than a distance Dt below the level of the peripheral ring between 4.6 mm and 6.1 mm and is preferably substantially equal to 5.1mm.
• the invention also relates to an internal combustion engine adapted to pollution control standards strict concerning the emission of nitrogen oxides and particles and more particularly a diesel type internal combustion engine remarkable in that it comprises at least one piston according to the invention.
• This internal combustion engine of the diesel type may have a cylinder of axis of revolution C whose upper end is closed by a yoke provided with a lower face which contributes to define a combustion chamber with the front face of the piston whose piston bowl is centered around an axis of revolution B, said engine comprising, opening from the lower face of the cylinder head, at least one intake duct that can be closed by an intake valve and at least one duct exhaust capable of being closed by an exhaust valve, a glow plug and a fuel injector whose nose opens into the combustion chamber at an injector axis I parallel to the axis of revolution of the cylinder C and remote therefrom, the injector making an angle Ai with the injector axis I of between 15 ° and 15.5 °, in that the cylinder C, bowl B and injector I
• FIG. 1 is a partial schematic section of an internal combustion engine according to the invention.
• FIG. 2 is a partial section in a plane containing the axis of revolution of the piston bowl detailing the head of a piston according to the invention, admission side.
• FIG. 1 illustrates an internal combustion engine 100, especially for a diesel engine, comprising at least one cylinder 1 of axis of revolution C, a cylinder head 2 and a piston 3.
• this axis of revolution C is oriented upwards towards the cylinder head 2.
• the piston 3 is slidably mounted in the cylinder 1 along the axis of revolution of the cylinder C "and has a body piston member adapted to receive an axis for connecting the piston to a driving rod head, said body being delimited laterally by a piston skirt 31 extending parallel to the axis of revolution of the cylinder C and cooperating with an inner wall of the cylinder 1.
• the piston further comprises a front face 32 which cooperates with the lower face 20 of the cylinder head 2 to define a combustion chamber of the cylinder 1.
• the fresh air or a mixture of fresh air and gas of reclrculated exhaust is admitted into the combustion chamber by at least one intake duct 5 formed in the cylinder head 2 and which can be closed by at least one intake valve 50.
• the combustion residues of the fuel air mixture Introduced are evacuated by at least one duct exhaust 6 formed in the cylinder head 2, and which can be closed by at least one exhaust valve 60.
• a glow plug 4 is located in the cylinder head 2, its end opening into the combustion chamber so as to heat the fuel air mixture during cold starts.
• a fuel injector 7 is located in the cylinder head 2 and opens into the combustion chamber.
• the injector 7 is arranged such that it is offset with respect to the axis of the cylinder C.
• the nose of the injector 7 opens at an axis I called “d” injector "parallel to the axis of symmetry of the cylinder C,
• the injector 7 is inclined by an angle Ai between 15 ° and 15.5 ° taken from the axis of injector I in the anti-geometric direction.
• the end face 32 comprises a central stud 321, a peripheral crown
• said bowl 323 extending from the central pin 321 to the peripheral ring 322 to which it is connected.
• the cylinder C, bowl B and injector I axes are aligned in a common plane, the distance separating the cylinder axis C from the bowl axis B being substantially equal to 1.25 mm and the distance separating the cylinder axis C of the injector axis I being substantially equal to 4 mm.
• the peripheral ring 322 extends laterally from the skirt 31 of the piston 3 towards the axis of revolution B of the bowl 323 to a lip forming end 3220 below which the bowl 323 has a torus 3230 in profile. oven of maximum radius of curvature Rt between 4.2 mm and 5.8 mm and preferably substantially equal to 4.5 mm.
• the lip 3220 is located at a distance De / 2 from the axis of revolution B of the bowl 323, the distance De being between 45 and 48 mm and preferably substantially equal to 47roin.
• the torus 3230 is located at a distance Db / 2 from the axis of revolution B of the bowl 323, the distance Db being between 48 mm and 51 mm and preferably substantially equal to
• the injector 7 is adapted to selectively inject fuel in the form of directed jets into an upper region of the torus 3230 adjacent to a lower edge of the lip 3220, also referred to as a reentrant R, so as to improve fuel jet guidance from this reentrant R by winding on the walls of the torus 3230 to the bottom of the bowl, where is the oxygen during the ascent of the piston 3, to reduce the smoke and to prepare the flow of gas to the central pin 321.
• a reentrant R will be maintained while maintaining a difference in distances, with respect to the axis of revolution B of the bowl 323, the end of the ring De / 2 and the end of the core Db / 2 substantially equal at lmm.
• the thickness Ep of the lip 3220 corresponding to the distance of the reentrant R of the peripheral ring 322 is between 3mm and 5mm and preferably substantially equal to 4.5mm.
• the maximum depth P of the bowl 323 is between 13 mm and 14.5 mm and preferably substantially equal to 13.5 mm. Such a depth P has the advantage of offering a quantity of air trapped at the bottom of the large bowl 323 in order to of its mixture with the fuel.
• the combination of this definition of reentrant R, torus 3230 and maximum depth P of bowl 323 allows improved fuel jet guidance to a volume of air trapped at the bottom of bowl 323.
• the central pin 321 has an upper slope of distinct angle A1 and lower A2 angle, the upper angle slope Al being softer than the lower angle slope A2.
• the upper angle slope A1 taken from the axis of revolution B of the bowl 320 in the geometric direction is between 69 ° and 84 ° and is preferably substantially equal to 72 °.
• the lower angle slope A2 taken from the axis of revolution B of the bowl 320 in the geometric direction is between 47 ° and 62 ° and is preferably substantially equal to 59 °.
• the use of a steep lower slope of angle A2 makes it possible to retain more air at the bottom of the bowl 320 than in the case of a central nipple 321 with a single slope.
• An internal combustion engine 100 provided with a piston 3 combining these characteristics is particularly advantageous for use with respect to an internal combustion engine provided with a piston adapted to current pollution control standards, of the Euro 4 type. tests were carried out with a motor 100 which has the following additional features, a bore of 76mm, a compression ratio of about 15 and a swirl level at low dead point Nd / N close to 2.
• this motor 100 emits nitrogen oxides and particles in an amount less than about 10%. Under the same load conditions, a reduction of about 20% in HC unburned hydrocarbons is also observed.

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Combustion Methods Of Internal-Combustion Engines (AREA)
• Pistons, Piston Rings, And Cylinders (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (7)

Families Citing this family (5)

Citations (3)

Family Cites Families (17)

• 2007
  • 2007-12-19 FR FR0759982A patent/FR2925602A1/fr active Pending
• 2008
  • 2008-12-15 EP EP08861953A patent/EP2232028A1/fr not_active Withdrawn
  • 2008-12-15 JP JP2010538636A patent/JP2011506848A/ja active Pending
  • 2008-12-15 CN CN2008801270142A patent/CN101952567A/zh active Pending
  • 2008-12-15 WO PCT/EP2008/067565 patent/WO2009077507A1/fr active Application Filing
  • 2008-12-15 US US12/809,312 patent/US20110011365A1/en not_active Abandoned
  • 2008-12-15 RU RU2010129531/06A patent/RU2472949C2/ru active

Patent Citations (3)

Non-Patent Citations (1)

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