Classifications

• • 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
  • F02M51/00—Fuel-injection apparatus characterised by being operated electrically
  • F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
  • F02M51/0603—Injectors peculiar thereto with means directly operating the valve needle using piezoelectric or magnetostrictive operating means
• • 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
  • F02B23/08—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition
  • F02B23/10—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition with separate admission of air and fuel into cylinder
  • F02B23/101—Other engines characterised by special shape or construction of combustion chambers to improve operation with positive ignition with separate admission of air and fuel into cylinder the injector being placed on or close to the cylinder centre axis, e.g. with mixture formation using spray guided concepts
• • 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
  • F02M45/00—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship
  • F02M45/12—Fuel-injection apparatus characterised by having a cyclic delivery of specific time/pressure or time/quantity relationship providing a continuous cyclic delivery with variable pressure
• • 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
  • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
  • F02M61/04—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series
  • F02M61/08—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00 having valves, e.g. having a plurality of valves in series the valves opening in direction of fuel flow
• • 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
  • F02B75/12—Other methods of operation
  • F02B2075/125—Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-combustion chamber
• • 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 to a method for operating an internal combustion engine with direct injection, in particular a spark-ignited internal combustion engine with direct injection, with the features of the preamble of claim 1.
• a method for operating a diesel engine is known from DE 100 40 117 A1, in which an especially fast cross-sectional release of an injector valve attempts to achieve a good homogenization of the fuel / air mixture. aim.
• the injector valve is suddenly opened to improve the homogenization of the fuel / air mixture by means of a sharp injection course.
• a method for forming an ignitable fuel-air mixture in which the fuel is introduced into the combustion chamber of the internal combustion engine in at least two partial quantities, the closure body of an injection nozzle being able to be brought into its closed position after the injection process of a partial quantity.
• the fuel jet is accelerated up to the outlet by the nozzle opening continuously tapering towards the outlet with a curved or parabolic outlet cross section.
• the document DE 19642653 C1 discloses a method for forming a mixture of an internal combustion engine with direct injection, with which an opening stroke of a valve member relative to a valve seat of an injector and the injection time can be variably adjusted during fuel injection, thereby making it possible to influence an injection angle and also the fuel mass flow dynamically. Since different fuel sprays are produced in the injection nozzles due to production, which often lead to misfires due to different mixture formations, hardly any feasible improvements to the respective geometry of the injection nozzle would have to be made before installation in an internal combustion engine.
• the object of the invention is to design the injection behavior of an injection nozzle in such a way that an optimal injection behavior and accordingly an improved combustion can be achieved despite manufacturing tolerances.
• the inventive method is characterized by the formation of an ignitable fuel / air mixture in a combustion chamber of a direct injection internal combustion engine with an injection nozzle having a closure body, in which an operating stroke and a fuel injection time can be variably adjusted.
• the closure body of the injection nozzle is moved from a closed position to an operating position for setting an operating stroke by means of a control device such that the closure body is moved between the closed position and the operating position with a varying acceleration during a fuel injection process in such a way that up to the setting of the Operating speeds different speeds can be set.
• the opening behavior of the injection nozzle is designed in such a way that an increase in the momentum of the injected fuel drops occurs when exiting the injection nozzle and the fuel drop decays after the fuel exits is reinforced from the outlet cross section of the injection nozzle.
• the closure body of the injection nozzle is preferably brought into an operating position in such a way that a required duration between two operating positions, the closed state also representing an operating position, being less than 200 ⁇ sec.
• the closure body is opened in such a way that the closure body is moved at a high and constant speed up to the operating position, which remains below the level of a maximum achievable speed. Due to the sudden opening and the rapid adjustment of the operating position of the closure body, the fuel flows from the injection nozzle into the combustion chamber with a higher momentum, which results in an increased atomization of the fuel droplets. This allows manufacturing tolerances to be compensated, i.e. The flow behavior of the fuel from the injection nozzle is hardly influenced by the manufacturing errors that occur.
• the opening of the injection nozzle is designed in such a way that when the closure body is moved to an operating position, it is first moved at a reduced speed and then with a continuous increase in speed to a maximum value when the operating position is reached.
• This also increases the atomization properties, which improves the properties of engine combustion, in particular consumption and emissions.
• the symmetry in the generated spray pattern of the injected fuel is improved and further fluctuations in the spray pattern due to production are compensated for.
• the opening of the injection nozzle is designed such that the closure body of the injection nozzle is first moved at a reduced speed and then at an increasing speed up to a maximum value when approaching an operating position, the closure body being reached shortly before the operating position is reached is moving at a slowing speed.
• the opening of the injection nozzle is designed in such a way that the closure body of the injection nozzle is moved at an increased constant speed to an intermediate position which corresponds to a stroke which is greater than the operating stroke. If the intermediate position is reached, the closure body is returned to the operating position immediately or after a certain holding time.
• the closure body can be moved to the intermediate position according to a previous embodiment of the invention, the closure body generally being able to be moved according to a combination of the proposed embodiments.
• the opening of the injection nozzle is designed such that the closure body of the injection nozzle is moved up to an operating position A at an increased and constant speed. If the position A is reached, the closure body is moved after a certain holding time T AH at an increased and constant speed up to an operating position B, which corresponds to a stroke which is greater than the stroke of the operating position A. If the position B is reached, the closure body is moved into the closed position immediately or after a certain holding time T BH at an increased and constant speed.
• the method according to the invention is suitable for use in direct-injection gasoline engines in which a well-prepared mixture must be present in the area of the spark plug within a very short time, the method according to the invention being suitable for both spark-ignited and self-igniting internal combustion engines with direct injection. Accordingly, the manufacturing-related deviations of the injection jet are compensated for, which has a positive influence on the spray pattern according to the invention. As a result, a uniform distribution of the fuel is achieved in all areas of the injected fuel jet. This leads to the maintenance of a required symmetry of an injected fuel jet in all working cycles, whereby a minimization or elimination of undesired tipping phenomena is realized.
• the method according to the invention is used particularly in the case of injectors opening outwards, in which the fuel is injected as a hollow cone.
• Such injection nozzles are preferably used in spark-ignited internal combustion engines in which there is a jet-guided combustion process.
• the fuel is injected in such a way that a toroidal vortex is formed at the end of the hollow fuel cone, the electrodes of a spark plug arranged in the combustion chamber being arranged outside the injected hollow fuel cone, but within a fuel / air mixture formed in the form of the toroidal one Vertebrae lie.
• the method according to the invention maintains a necessary symmetry of the toroidal vertebra and prevents the toroidal vertebra from tilting.
• 1 is a sectional view of a cylinder of a direct injection spark ignition internal combustion engine
• FIG. 2 shows a schematic diagram with a stroke curve of a closure body of a fuel injection nozzle of the internal combustion engine from FIG. 1 until an operating position is reached, plotted over time
• FIG. 3 shows a schematic diagram with a stroke profile of a closure body of a fuel injection nozzle of the internal combustion engine from FIG. 1 until an operating position is reached plotted over time according to a second method example according to the invention
• FIG. 4 shows a schematic diagram with a stroke profile of a closure body of a fuel injection nozzle of the internal combustion engine from FIG. 1 until an operating position is plotted against time according to a third example of the method according to the invention, and s
• FIG. 5 shows a schematic diagram with a stroke profile of a closure body of a fuel injection nozzle of the internal combustion engine from FIG. 1 until an operating position is plotted against time according to a fourth method example according to the invention.
• Fig. 1 shows a cylinder 2 of a spark-ignition internal combustion engine 1 with direct injection, in which a combustion chamber 4 between a piston " 3 and a cylinder head 5.
• the piston 3 is held in a longitudinally displaceable manner, the longitudinal mobility of the piston 3 being limited by an upper dead center and a lower dead center.
• the internal combustion engine 1 shown in FIG the four-stroke principle, the method according to the invention being equally suitable for both spark-ignited and self-igniting two-stroke internal combustion engines with direct injection.
• combustion air is supplied to the combustion chamber 4 through an inlet duct 13, the piston 3 moving downwards to bottom dead center UT
• the piston 3 moves in an upward movement from the bottom dead center to the top dead center OT, the fuel being injected during the stratified charge mode of the internal combustion engine 1 in the region of the top dead center OT by means of a spark plug 7 the fuel-air mixture is ignited, the piston 3 expanding in a downward movement to bottom dead center UT.
• the piston 3 moves upwards to the top dead center TDC and pushes the exhaust gases out of the combustion chamber 4.
• the internal combustion engine 1 is operated in such a way that the stratified charge mode is operated in the lower and middle speed and load ranges and the homogeneous mode is operated in the upper load range.
• the fuel is injected in stratified charge mode in the compression stroke, preferably in a crank angle range between 40 and 10 ° before TDC.
• the fuel is preferably injected into the combustion chamber 4 in two subsets. .
• an outward-opening injection nozzle 11 is preferably used, with which a hollow fuel cone 8, preferably with an angle ⁇ between 70 ° and 100 °, is generated.
• a toroidal vortex 10 is formed in the combustion chamber 4 in such a way that an ignitable fuel / air mixture forms in the region of the electrodes 12 of the spark plug 7 . is achieved.
• the spark plug 7 is arranged in such a way that the electrodes 12 of the spark plug 7 protrude into the vortex obtained, during the fuel injection they lie outside the lateral surface 9 of the fuel cone 8. As a result, the electrodes 12 of the spark plug 7 are not wetted with fuel.
• the toroidal vortex 10 obtained should have a uniform fuel distribution over the entire area, so that the vortex does not tilt, and furthermore when Mounting the fuel valve 6 a defined rotational position of the fuel valve 6 in the cylinder head 5 can be avoided.
• FIG. 2 shows a schematic stroke profile of the closure body, not shown, of the injection nozzle 11 according to FIG. 1 over time T.
• the fuel is injected in such a way that the opening time T B ⁇ of the closure body of the injection nozzle 11 until an operating stroke H is set B is completed over a period of approximately 100 ⁇ sec to 200 ⁇ sec.
• the fuel from the injection nozzle 11 is accelerated in such a way that the fuel droplets have a higher momentum when they enter the combustion chamber 4, thereby atomization and a quickxex mix with dex combustion air already present in the combustion chamber.
• the faster opening avoids an uneven fuel distribution in the fuel cone 8 caused by manufacturing tolerances.
• the aim is to achieve a symmetrical vortex 10 with a uniform fuel distribution without undesired tilting 1 , i.e. a horizontal 15 through the vortex 10 formed should, as far as possible, be in a position perpendicular to the fuel valve axis 14 in all injection processes during the entire operating time of the internal combustion engine 1 are located.
• the formation of streaks at the end of the fuel cone 8 or the vortex 10 should also be avoided.
• FIG. 3 a second example of the method is shown, in which the closure body of the injection nozzle 11 is opened in such a way that it is first started at a reduced or low speed, with a continuous increase in speed up to a maximum value when setting the Operating strokes H B is made.
• the closure body is slowly opened, first little fuel flows into the combustion chamber 4, which is braked by the existing counterpressure in the combustion chamber, and then is pulled into the combustion chamber 4 with a higher impulse by the fuel that shoots out further, so that better atomization and uniform distribution of the fuel in the cone 8 is achieved.
• the fuel particles Due to the uniform distribution of the fuel in the entire region of the toroidal vortex 10, the fuel particles are transported into the outer region of the vortex 10 in the direction of the electrodes 12 of the spark plug 7 and concentrated there.
• FIG. 4 shows a further exemplary embodiment of the invention, in which first the closure body of the injection nozzle 11 is slowly opened and, after a short time, is opened further at an increasing speed, the speed of the closure body decreasing shortly before the operating stroke H B is reached. Similar to the previous exemplary embodiment, the fuel particles are brought into the combustion chamber 4 with a higher momentum and distributed evenly in the toroidal vortex 10.
• FIG 5 shows a further exemplary embodiment in which the closure body is brought to an intermediate stroke position H z at a high speed within a time T z , the intermediate stroke position H z being greater than the operating stroke H B. If the intermediate stroke position H z is reached, the closure body is moved back to the operating stroke within the duration T B2 immediately or after a certain holding time T ZH .
• the fuel particles are accelerated out of the injection nozzle in such a way that they are injected into the combustion chamber with a very high impulse. This results in better atomization and thus compensates for manufacturing tolerances.
• a higher speed is achieved when the injection nozzle is opened, which causes the fuel to decay more intensely.
• FIG. 6 a further embodiment is illustrated, in which the closure body is engaged with 'a high speed to a lift position A within a time T H A. If the stroke position H A is reached, the closure body is opened after a certain holding time T AH with an l ⁇
• the process examples shown enable optimal combustion and a pronounced toroidal vortex formation is achieved.
• the fuel particles are concentrated in the edge region of the vortex 10 in such a way that there are more drops in the edge region. This creates a larger contact area with the combustion air.
• the formation of a vortex 10 with a constant symmetry and a uniform, uniform fuel distribution is achieved.
• the installation of fuel valves is made easier since a defined rotational position of the fuel valve 6 is not required.
• Another advantage is the compensation of manufacturing inaccuracies in the manufacture of fuel valves, which generally negatively affect the mixture formation in the direct-injection internal combustion engines.
• the fuel is preferably injected into the combustion chamber in stratified charge mode at a combustion chamber back pressure of approximately 16 bar, which corresponds to a point in time of approximately 30 ° crank angle before TDC.
• This fuel injection is carried out in stratified charge mode, with the internal combustion engine operating in homogeneous mode 1 the fuel injection can be carried out in the intake stroke of the internal combustion engine.
• the change in operating position of the closure body of the injection nozzle 11 is to be achieved in less than 200 ⁇ sec.
• the injection pressure of the injector 11 is varied between 100 bar and 300 bar or between 150 bar and 250 bar, the fuel jet 8 emerging from the injector 11 being conical with a jet angle between 70 ° and 100 °.
• the invention relates to a method for forming a fuel / air mixture of a direct-injection internal combustion engine, with which a closure body of the fuel injector is moved from a closed position to an operating position for setting an operating stroke by means of a control device such that until the operating stroke is set different speeds are set to allow an optimum combustion ', and to allow a uniform concentration of the introduced with a higher pulse into the combustion chamber fuel particles in the edge area of the vortex at a torusformigen vortex formation, so that formation of a tip vortex with a constant symmetry and a even distribution of fuel is achieved.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fuel-Injection Apparatus (AREA)
• Combustion Methods Of Internal-Combustion Engines (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Applications Claiming Priority (3)

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• 2002
  • 2002-07-11 DE DE10231582A patent/DE10231582A1/de not_active Withdrawn
• 2003
  • 2003-07-01 WO PCT/EP2003/006992 patent/WO2004007944A1/de not_active Application Discontinuation
  • 2003-07-01 EP EP03763682A patent/EP1521911A1/de not_active Withdrawn
  • 2003-07-01 JP JP2004520454A patent/JP4260741B2/ja not_active Expired - Fee Related
• 2005
  • 2005-01-10 US US11/032,319 patent/US7047946B2/en not_active Expired - Fee Related

Non-Patent Citations (1)

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