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
  • F02B23/0678—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
  • F02B23/0693—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 the combustion space consisting of step-wise widened multiple zones of different depth
• • 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
  • F02B23/0645—Details related to the fuel injector or the fuel spray
  • F02B23/0648—Means or methods to improve the spray dispersion, evaporation or ignition
  • F02B23/0651—Means or methods to improve the spray dispersion, evaporation or ignition the fuel spray impinging on reflecting surfaces or being specially guided throughout the combustion space
• • 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
  • F02B23/0645—Details related to the fuel injector or the fuel spray
  • F02B23/0666—Details related to the fuel injector or the fuel spray having a single fuel spray jet per injector nozzle
• • 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
  • F02B23/0645—Details related to the fuel injector or the fuel spray
  • F02B23/0669—Details related to the fuel injector or the fuel spray having multiple fuel spray jets per injector nozzle
• • 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
  • F02B75/00—Other engines
  • F02B75/04—Engines with variable distances between pistons at top dead-centre positions and cylinder heads
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D15/00—Varying compression ratio
  • F02D15/02—Varying compression ratio by alteration or displacement of piston stroke
• • 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 direct injection of fuel with variable compression ratio, in particular for a motor vehicle, and to an injection method for such an engine.
• the combustion systems of internal combustion engines must meet the demands of reducing pollutant emissions, increasing torque and specific power, and reducing combustion noise, while remaining compatible with the performance criteria. endurance.
• the compression ratio of an engine is the ratio between the volume of the combustion chamber when the piston is in the bottom dead center position and the volume of this chamber when in the neutral position. high, says dead volume.
• some of these devices offer the possibility of changing the compression ratio of this engine by changing the dead volume of the combustion chamber at the top dead center of the piston. For this, simply change the final position of the piston relative to the cylinder head when it is at its top dead center.
• this type of engine generally comprises a cylinder, a piston comprising a pin disposed in a concave bowl and sliding in this cylinder in a reciprocating rectilinear movement, admission means of an oxidizer, means for exhausting burnt gases, means for varying the position of the top dead center of the piston, and injection means for injecting a fuel into the combustion chamber of this engine.
• the fuel injection means comprise an injector with two rows of superimposed injection ports for injecting the fuel in the form of one or two layers of fuel jets. superimposed.
• the fuel is injected in a single layer of jets and, for a low compression ratio, the fuel is injected at the two ply angles.
• This type of engine therefore requires a multi-layer fuel injector which is complex in design and must necessarily be associated with a sophisticated control device to make operational one and / or the other ply of fuel jets.
• the present invention proposes to remedy these drawbacks with a motor which comprises a conventional injector with a single ply of fuel jets which injects the fuel into combustion and combustion zones of the combustion chamber, whatever the rate compressor used for the engine.
• the present invention relates to a variable compression ratio direct injection internal combustion engine comprising at least one cylinder, a cylinder head carrying a fuel injection means projecting fuel in a single layer of fuel jets, a sliding piston in this cylinder, and a combustion chamber delimited on one side by the upper face of the piston having a pin extending towards the cylinder head and disposed in the center of a concave bowl, characterized in that the combustion chamber comprises at least two mixing zones in which the fuel jets are injected, one of the zones being used for a maximum compression ratio and the other of the zones being used for a minimum compression ratio.
• One of the zones may be associated with the other zones for the minimum compression ratio.
• the mixing zones can be located axially one above the other.
• the mixing zones may be delimited from one another by a radial projection.
• One of the mixing zones may include a concave surface connected to a convex surface to form the bottom portion of a toric volume.
• the other of the mixing zones may comprise a concave surface connected to a convex surface to form a barrier.
• the engine may comprise a piston with a bowl which has a bowl diameter BD, a neck diameter GD, a low bend diameter ID1, a top bend diameter ID2, a height H of teat, a height L of the bowl , a height L1 of the inflection diameter ID1, an inclination angle a3, a radius R for the rounded concave surface of the torus and a radius R2 for the concave rounded surface, the dimensions of the bowl being able to satisfy at least one of following conditions:
• the ratio BD / L is substantially between 1, 3 and 1, 8,
• the ratio GD / BD is substantially between 0.9 and 0.95 for the aerodynamics of the torus and the recovery of the fuel jets
• the ratio H / L is substantially less than 0.6 and substantially greater than 0.5 to minimize the volume of oxidant between the nose of the injector and the nipple,
• the ratio L / L1 is substantially between 1, 15 and 1, 7
• the ratio R2 / R is substantially between 0.25 and 1,
• the ratio GD / ID is substantially between 0.65 and 0.9
• A3 is substantially between 50 and 70 °
• ⁇ BD bowl diameter is smaller than ID2 diameter.
• the invention also relates to a fuel injection method for a variable compression ratio direct injection internal combustion engine comprising at least one cylinder, a cylinder head carrying a fuel injection means throwing fuel in a single layer of fuel. jets of fuel, a piston sliding in this cylinder, and a combustion chamber delimited on one side by the upper face of the piston having a pin extending in the direction of the cylinder head and disposed in the center of a concave bowl, characterized in that, for a maximum compression ratio, the fuel is injected into a mixing zone of the combustion chamber and, for a minimum compression ratio, the fuel is injected into another mixing zone of said combustion chamber. For the minimum compression ratio, the fuel can be injected into the two mixing zones.
• FIG. 1 which shows an internal combustion engine with a variable compression ratio according to the invention, in a configuration for a compression ratio
• FIG. 2 which is another view of the engine of FIG. 1 for another compression ratio
• FIG. 3 which is a partial large-scale local view of the profile of the bowl of FIGS. 1 and 2.
• FIGS. 1 and 2 illustrate, in a nonlimiting manner, an internal combustion engine with variable compression ratio and with direct injection of fuel.
• This engine is advantageously a compression ignition engine using a diesel type fuel.
• any other fuel having the physicochemical characteristics allowing the operation of a compression ignition type engine including a direct injection system can be used, such as kerosene.
• This engine comprises at least one cylinder 10, a cylinder head 12 closing the cylinder in the upper part, fuel injection means 14 carried by the cylinder head and a piston 1 6 XX axis sliding in the cylinder in a reciprocating rectilinear motion.
• This engine also comprises a flue exhaust means 18 with at least one exhaust pipe 20 whose opening can be controlled by any means, such as for example an exhaust valve 22 and an intake means 24.
• an oxidizer with at least one intake manifold 26 whose opening can be controlled by any means, such as an intake valve 28.
• oxidizer it includes air at ambient pressure or supercharged air or a mixture of air (supercharged or not) with flue gas.
• the injection means comprise a fuel injector 30, preferably arranged in the axis XX of the piston, whose nose comprises a multiplicity of orifices through which the fuel is sprayed and projected towards the combustion chamber 32 of the piston. engine. It is from this injector that the projected fuel forms a single layer
• nappe angle it is understood the angle at the top that forms the cone of jets coming from the injector and whose imaginary peripheral wall passes through all the axes 38 of the fuel jets 36.
• the combustion chamber 32 is delimited by the internal face of the cylinder head 40 opposite the piston, the circular inner wall 41 of the cylinder 10 and the upper face 42 of the piston 1 6.
• This upper face of the piston comprises a concave bowl 44, here of axis coincident with that of the cylinder, whose concavity is turned towards the cylinder head and which houses a pin 46 located substantially in the center of the bowl, which rises towards the cylinder head 12 , preferably being coaxial with the axis of the fuel jet web.
• the stud 46 of generally frustoconical shape, has an apex 48 preferably rounded, continuing, deviating symmetrically from the axis XX towards the outside of the piston, by an inclined surface 50 substantially rectilinear to arrive at a bottom 52 of the bowl.
• the bottom of this bowl is rounded with a curved rounded concave surface 54, called the inner rounded surface, connected to the bottom of the inclined sidewall and another concave rounded surface 56 in an arc of a circle, said surface outer rounded, connected at one end to the low end of the inner rounded surface and the other of its ends to a side wall 58, here substantially rounded towards the axis XX, thereby forming a radial projection 59 in the direction of the stud.
• the two rounded surfaces 54 and 56 thus delimit the lower part of a toric volume 60 (or torus) delimited at the top by the seam 59.
• the rounded side wall 58 continues, always away from the axis XX, by a concave rounded surface 62 which is continued by an outer convex surface 64 which arrives at a flat surface 66 advancing to the vicinity of the wall 41 of the cylinder.
• the surfaces 62 and 64 then forming a barrier 67 whose role will be explained in the following description.
• the combustion chamber thus comprises two distinct zones Z1 and Z2 which ensure the mixing between the oxidant they contain (air [supercharged or not] or mixture of air and recirculated flue gas) and the fuel coming from the injector, as well as the combustion of the carbureted mixture thus formed when the physicochemical conditions of this mixture are ensured to ensure such combustion.
• the zone Z1 which is delimited by the pin 46, the torus 60 of the bottom of the bowl and the radial projection 59, forms the lower zone of the combustion chamber.
• the engine of FIGS. 1 and 2 is a variable compression ratio engine with a change in compression ratio by modifying the dead volume of the combustion chamber at the top dead center of the piston by modifying the final position of the piston. relative to the breech.
• This engine is associated with a computer (not shown), said engine calculator, containing engine operation maps according to various parameters, such as the engine speed or load, to determine the appropriate compression ratio, and fuel injection management means according to the compression ratio with which the engine is operating.
• the computer controls the variation device of the compression ratio so that the piston is in PMH Tm ax-
• the computer controls the fuel injection parameters so that the fuel jets 36 are sent into the mixing zone Z1 of the combustion chamber.
• the fuel jets of the web 34 directly target the torus 60 by performing a path according to the arrow F1 for a better air / fuel mixture and allowing almost complete combustion in this torus.
• the computer controls the variation device of the compression ratio so that the piston is in PMH Tm ini (FIG. 2).
• the computer controls the fuel injection parameters so as to control the introduction of the jets of fuel 36 in the mixing zone Z2 of the combustion chamber so that they come to impact the concave surface 62 and develops along the arrow F2.
• this injection can be performed in such a way that the fuel jets impinge on the outer edge of the projection 59 closest to the stud.
• the fuel jets separate into two streams of fuel, one of the streams being introduced into the zone Z1 and the other flows in the zone Z2, as illustrated by the arrows F1 and F2 of Figure 2 , so that the combustion takes place in these two zones.
• FIG. 3 illustrates, on a larger scale and without limitation, a portion of the bowl profile described above.
• the bowl includes:
• a bowl diameter BD with a radius considered near the bottom of the bowl and corresponding to a distance taken between the axis XX and the point furthest from the concave surface 56 by contributing to this axis
• the dimensions of the bowl may satisfy at least one of the following conditions:
• the ratio BD / L is substantially between 1, 3 and 1, 8,
• the ratio GD / BD is substantially between 0.9 and 0.95 for the aerodynamics of the torus and the recovery of the fuel jets
• the ratio H / L is substantially less than 0.6 and substantially greater than 0.5 to minimize the volume of oxidant between the nose of the injector and the nipple,
• the ratio L / L1 is substantially between 1, 15 and 1, 7
• the ratio R2 / R is substantially between 0.25 and 1,
• the ratio GD / ID is substantially between 0.65 and 0.9
• A3 is substantially between 50 and 70 °
• the bowl diameter BD is smaller than the inflection diameter high ID2.
• the combustion of the fuel / oxidant mixture for the maximum compression ratio takes place essentially in the volume of the torus while the combustion of the fuel / oxidant mixture for the minimum compression ratio takes place essentially in the upper zone and above the piston, and preferably in the volume of the torus as well as in the upper zone and above the piston.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Dispersion Chemistry (AREA)
• Combustion Methods Of Internal-Combustion Engines (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=55862971

Family Applications (1)

Country Status (6)

Families Citing this family (9)

Family Cites Families (11)

• 2016
  • 2016-01-26 FR FR1650592A patent/FR3047043B1/fr active Active
• 2017
  • 2017-01-09 CN CN201780007826.2A patent/CN108474291A/zh active Pending
  • 2017-01-09 US US16/072,905 patent/US20190040789A1/en not_active Abandoned
  • 2017-01-09 JP JP2018538822A patent/JP2019503451A/ja not_active Withdrawn
  • 2017-01-09 WO PCT/EP2017/050328 patent/WO2017129386A1/fr active Application Filing
  • 2017-01-09 EP EP17700172.4A patent/EP3408513A1/de not_active Withdrawn

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