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
  • F02B75/00—Other engines
  • F02B75/04—Engines with variable distances between pistons at top dead-centre positions and cylinder heads
  • F02B75/048—Engines with variable distances between pistons at top dead-centre positions and cylinder heads by means of a variable crank stroke length
• • 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
  • F02B75/045—Engines with variable distances between pistons at top dead-centre positions and cylinder heads by means of a variable connecting rod length
• • 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
  • F02B41/00—Engines characterised by special means for improving conversion of heat or pressure energy into mechanical power
  • F02B41/02—Engines with prolonged expansion
  • F02B41/04—Engines with prolonged expansion in main cylinders

Definitions

• the invention relates to a multi-joint crank drive of an internal combustion engine, with a plurality of rotatably mounted on Hubzapfen a crankshaft Koppelgliederh and a plurality of rotatably mounted on Hubzapfen an eccentric Anlenkpleueln, each of the coupling members is pivotally connected to a piston connecting rod of a piston of the internal combustion engine and one of the Anlenkpleuel.
• the invention further relates to a method for operating such a multi-joint crank drive.
• the multi-joint crank drive de aforementioned type is for example part of the internal combustion engine, but can also be found in other areas application.
• the multi-joint crank drive comprises the eccentric shaft, whose angle of rotation can preferably be adjusted by means of an adjusting device, in particular as a function of an operating point of the internal combustion engine.
• the eccentric shaft can also be operatively connected to a crankshaft of the internal combustion engine and driven by it in this way.
• the multi-link crank drive has a number of coupling pistons corresponding to the number of pistons of the internal combustion engine, each of which is rotatably mounted on the corresponding crank pin of the crankshaft and has two arms protruding beyond the crankshaft on opposite sides and each having a pivot joint at its end.
• One of the pivot joints is used for pivotal connection with the piston connecting rod, which connects one of the pistons of the internal combustion engine via the coupling member with the crankshaft.
• Another of the pivot joints is used for pivotal connection with the so-called Anlenkpleuel, which is rotatably mounted with its other end on the crank pin of the eccentric shaft.
• the Anlenkpleuel has for this purpose preferably on the two connecting rods.
• the first connecting rod eye is part of the pivot joint, via which the Anlenkpleuel interacts with the coupling member.
• the first connecting rod eye comprises, for example, a coupling pin or bearing pin held on the coupling member.
• the second connecting rod eye is analogous to part of the pivot joint, via which the Anschpleuel is connected to the eccentric shaft.
• the second connecting rod eye surrounds the crank pin of the eccentric shaft at least partially.
• the compression ratio achieved in a cylinder assigned to the respective piston can be set, in particular as a function of the operating point of the internal combustion engine and / or the present power stroke.
• the eccentric shaft is brought into a specific, the desired compression ratio corresponding angular position or the phase angle between the eccentric shaft and the crankshaft to a certain value.
• In normal crank drives for internal combustion engines is due to the finite length of Kolbenpleuels or a connecting rod of Kolbenpleuels the amount of piston acceleration at a top dead center of the piston higher than at a bottom dead center of the piston.
• crank mechanism for example, for an internal combustion engine, which is present as a four-cylinder engine with 180 degrees crank angle of the crankshaft, an unbalanced free mass force second order. This impairs the smoothness of the internal combustion engine.
• the document DE 10 2012 008 244 A1 is known.
• This relates to a multi-joint crank drive of an internal combustion engine, which is designed or adjusted to reduce free second-order mass forces such that a crankshaft rotation angle range of a suction phase is less than 180 °; that a crankshaft rotation angle range of a compression phase is greater than 180 °; that a crankshaft rotation angle range of an expansion phase is smaller than 180 °; and that a crankshaft rotation angle range of an ejection phase is greater than 180 °.
• the prior art shows the documents EP 2 053 217 A2 and EP 2,119,890 A1.
• crankshaft rotation angle range of intake phase is greater than 180 degrees
• crankshaft rotation angle range of a compression phase is less than 180 degrees
• crankshaft rotation angle range of an expansion phase greater than 180 degrees is, and that a crankshaft rotation angle range of a discharge phase is less than 180 degrees.
• the suction phase, the compression phase, the expansion phase and the ejection phase should in each case follow one another directly and in particular are associated with a piston stroke curve which describes the position of the piston via the crankshaft angle.
• the intake phase of the Kolbenhubkurve extends from a crankshaft angle, which is present at a top dead center, which occurs during a charge cycle (LOT) until a crankshaft angle, at a bottom dead center during the charge cycle (charge cycle UT, LUT) is present.
• the compression phase of the Kolbenhubkurve extends from the charge cycle UT to a top dead center, which is in the range of ignition (ignition TDC).
• the expansion phase of the piston stroke curve extends from this ignition TDC to a crankshaft angle which is present at a bottom dead center following the ignition (ignition UT, ZUT).
• the ejection phase of the piston stroke curve extends from the ignition UDC to the aforementioned gas exchange TDC.
• crankshaft rotation angle ranges for each of the phases mentioned are exactly 180 degrees. Due to the formation or adjustment of the multi-link crank drive to the above-described parameters, the piston speed of the at least one piston of the internal combustion engine decreases slightly over the piston speed of the normal crank drive in a crankshaft rotation angle range in at least one crankshaft angle range, particularly the crankshaft angle range of 270 degrees and / or 630 degrees , The ranges extend for example by at least ⁇ 5 degrees, at least ⁇ 10 degrees, at least ⁇ 15 degrees, at least ⁇ 20 degrees, at least ⁇ 25 degrees, at least ⁇ 30 degrees, at least ⁇ 35 degrees, at least ⁇ 40 degrees or at least ⁇ 45 Degree around said crankshaft rotation angle around.
• a preferred embodiment of the invention provides that an axis of rotation of the eccentric shaft is above a plane which receives a rotational axis of the crankshaft and is perpendicular to at least one cylinder longitudinal center axis.
• the plane is therefore jointly defined by the axis of rotation of the crankshaft and the cylinder longitudinal center axis.
• the plane In the longitudinal direction of the internal combustion engine - with respect to the axis of rotation of the crankshaft - the plane has the same position and direction as this axis of rotation. At the same time, it should be perpendicular to the at least one cylinder longitudinal central axis, so that the cylinder longitudinal central axis is present in the normal direction of the plane.
• the cylinder longitudinal center axis is assigned to a cylinder of the internal combustion engine and extends in its longitudinal direction.
• the cylinder longitudinal center axis is, for example, over the longitudinal extension of the cylinder in the center before.
• the plane may also be perpendicular to a plurality of cylinder longitudinal center axes of a plurality of cylinders of the internal combustion engine, particularly preferably perpendicular to the cylinder longitudinal center axes of all cylinders of the internal combustion engine.
• the eccentric shaft should now be arranged such that its axis of rotation is arranged above this plane. Particularly preferably, the entire eccentric shaft, ie not just its axis of rotation, is above this plane.
• the axis of rotation of the eccentric shaft is immediately adjacent to the plane, thus adjacent to this.
• this is the case for the entire eccentric shaft.
• the axis of rotation of the eccentric shaft or the entire eccentric shaft is arranged above the plane and is additionally spaced therefrom.
• crankshaft has a crank of 180 degrees.
• the internal combustion engine which is assigned to the multi-steering wheel crank mechanism, designed as a four-cylinder internal combustion engine. It is only important that the crankshaft has a crank of 180 degrees. Of course, however, a different from this value bend can be realized. Of course, however, one of four different numbers of cylinders may be provided, for example, two, three, five, six, eight or twelve cylinders, the crank being preferably adapted accordingly.
• a particularly preferred embodiment of the invention provides that in the intake phase, an upper dead center (charge exchange TDC) at a crankshaft angle of greater Above 0 degrees and at most 4 degrees, in particular of at least 2 degrees and at most 3 degrees, preferably of at least 2.4 degrees and at most 2.7 degrees, is present. Additionally or alternatively it can be provided that in the compression phase, a bottom dead center (charge change UT) at a crankshaft angle of greater than 180 degrees, in particular at a crankshaft angle of at least 185 degrees or at least 186 degrees and at most 190 degrees, at most 189 degrees or at most 188 degrees, more preferably from at least 186.9 degrees to at most 187.2 degrees, is present.
• the crankshaft angle may be in the range extending from 185 degrees to 188 degrees, 189 degrees or 190 degrees. Also, it can be realized in the range of 186 degrees to at most 188 degrees, 189 degrees or 190 degrees.
• a development of the invention provides that in the expansion phase, an upper dead center (ignition TDC) at a crankshaft angle greater than 360 degrees and at most 364 degrees, in particular of at least 362 degrees and at most 363 degrees, preferably of at least 362.4 degrees and at most 362.7 degrees, is present. Additionally or alternatively, it may be provided that in the ejection phase, a bottom dead center (ignition-UT) at a crankshaft angle greater than 540 degrees, in particular at a crankshaft angle of at least 545 degrees or at least 546 degrees and at most 550 degrees, at most 549 degrees or at most 548 degrees, more preferably from at least 546.9 degrees to at most 547.2 degrees, is present.
• the crankshaft angle is in the range of 545 degrees to 548 degrees, 549 degrees or 550 degrees. However, it may also be realized in the range of 546 degrees to 548 degrees, 549 degrees or 550 degrees.
• crankshaft in the angular range of intake phase and compression phase (charge change OT to ignition TDC) and / or the crankshaft angle ranges of expansion phase and ejection phase (ignition TDC to charge TDC) are equal to 360 degrees.
• crankshaft angle difference between the gas exchange TDC and the gas exchange UT is 184.5 degrees. Additionally or alternatively, the crankshaft angle difference between the charge cycle UT and the ignition TDC may be equal to 175.5 degrees. A further embodiment of the invention provides that the crankshaft angle difference between the ignition TDC and the ignition UT is equal to 184.5 degrees. Additionally or alternatively, it is possible for the crankshaft angle difference between the ignition UT and the gas exchange TDC to be 175.5 degrees.
• the invention further relates to a method for operating a multi-joint crank mechanism of an internal combustion engine, in particular a multi-link crank mechanism according to the preceding embodiments, wherein the multi-joint crank mechanism has a plurality of pivotally mounted on crank pins of a crankshaft coupling members and a plurality of crank pin eccentric shaft mounted Anlenkpleueln, each the coupling links is pivotally connected to a Kolbenpleuel a piston of the internal combustion engine and one of the Anlenkpleuel.
• crankshaft rotation angle range of an intake corresponds to a first value that is greater than 180 degrees
• a crankshaft rotation angle range of a compression phase corresponds to a second value
• a crankshaft rotation angle range of a discharge phase corresponds to a fourth value that is smaller than 180 degrees.
• the multi-joint crank drive is set in at least one further operating mode such that the crankshaft rotation angle range of the intake phase is different from the first value, in particular equal to 180 degrees, and / or that the crankshaft rotation angle range of the compression phase of the second Value is different, in particular equal to 180 degrees, and / or that the crankshaft rotation angle range of the expansion phase is different from the third value, in particular equal to 180 degrees, and / or that the crankshaft rotation angle range of the ejection phase is different from the fourth working, in particular equal to 180 degrees is.
• crankshaft rotational angle ranges of the individual phases should each be different from 180 degrees.
• at least one of the crankshaft rotation angle ranges should be selected differently from the value described above. He can also be equal to 180 degrees, for example.
• the crankshaft rotation angle range should always be selected such that optimal operation of the internal combustion engine is realized.
• the operating mode currently set on the multi-crank drive can be selected accordingly from the at least one operating mode and the at least one further operating mode, this being provided, for example, as a function of an operating state of the internal combustion engine and / or at least one operating parameter of the internal combustion engine.
• FIG. 1 shows a region of a multi-link crank drive of an internal combustion engine
• FIG. 2 shows a diagram in which curves of a piston stroke are plotted over a crankshaft angle
• Figure 3 is a diagram in which the piston speed and the piston acceleration are plotted against the crankshaft angle for a conventional crank mechanism
• Figure 4 is a graph in which the piston speed and the piston acceleration are plotted against the crankshaft angle for the multi-link crank mechanism.
• FIG. 1 shows a perspective view of a region of an internal combustion engine 1 which is present, for example, as a series internal combustion engine, in particular as a four-stroke four-cylinder inline internal combustion engine.
• the internal combustion engine 1 has a crankshaft 2 and a plurality of pistons 3 (here: four pistons 3), each of which is movably mounted in one of a plurality of cylinders of the internal combustion engine 1.
• Each of the pistons 3 is connected to the crankshaft 2 via a piston connecting rod 4.
• the crankshaft 2 is rotatably mounted in shaft bearings (not shown here) of a cylinder crankcase of the internal combustion engine 1 also not shown and has, for example, several serving for storage centric shaft journal 5 and a plurality of crank pins 6 (of which in the figure only one is visible), whose longitudinal center axes in different angular orientations are offset parallel to a rotation axis 7 of the crankshaft 2.
• the internal combustion engine 1 further comprises an eccentric shaft 8, which preferably has an axis of rotation 7 parallel to the axis of rotation 7 of the crankshaft 2.
• the eccentric shaft 8 is rotatably mounted, for example, next to the crankshaft 2 and above it in the cylinder crankcase and in particular coupled to the crankshaft 2.
• the eccentric shaft 8 is arranged such that its axis of rotation 9 is above a plane which receives the axis of rotation 7 of the crankshaft 2 and is perpendicular to at least one cylinder longitudinal center axis of one of the cylinders of the internal combustion engine 1.
• the eccentric shaft 8 is part of a ehrgelenkskurbeltriebs 10.
• This also has a plurality of coupling members 11 (here: four coupling members 11), which are each rotatably mounted on one of the crank pin 6 of the crankshaft 2.
• each of the pistons 3 is associated with such a coupling member 11.
• the coupling members 11 each have a lifting arm 12, which is connected via a pivot joint 13 pivotally connected to a lower end of one of Kolbenpleuel 4.
• An upper end of the respective Kolbenpleuels 4 is articulated via a further pivot joint 14 on the associated piston 3.
• each of the piston 3 is connected by the respective Kolbenpleuel 4 and the respective coupling member 11 with the crankshaft 2.
• the multi-joint crank drive 10 further comprises a number of Kolbenpleuel 4 and the coupling members 11 corresponding number of Anlenkpleueln 15. These are, for example, approximately parallel to the Kolbenpleueln 4 aligned and in the axial direction of the crankshaft 2 and the eccentric shaft 8 in each case approximately the same plane as the associated Kolbenpleuel 4, but arranged on the opposite side of the crankshaft 2.
• Each Anlenkpleuel 15 comprises a connecting rod 16 and two at opposite ends of the connecting rod 16 arranged connecting rod eyes 17 and 18, in particular with different inner diameters.
• the connecting rod eye 18 of each Anlenkpleuels 15 at the lower end of the connecting rod 16 surrounds a respect to the axis of rotation 9 of the eccentric shaft 8 eccentric crank pin 19 of the eccentric shaft 8 on which the Anlenkpleuel 15 is rotatably supported by a rotary bearing 20.
• the connecting rod eye 17 at the upper end of the connecting rod 16 of each Anlenkpleuels 15 forms part of a pivot joint 21 between the Anlenkpleuel 15 and a longer coupling arm 22 of the adjacent coupling member 11, which protrudes on the opposite side to the lifting arm 12 of the crankshaft 2 on this.
• the connecting rod 18 is for example, larger than the connecting rod 17; However, the multi-joint crank drive 10 can also be reversed or realized with the same size connecting rod 17 and 18.
• the eccentric shaft 8 has between adjacent eccentric crank pin 19 and at their ends for supporting the eccentric shaft 8 in shaft bearings serving, to the axis of rotation 10 coaxial shaft sections 23.
• a variable compression can be reduced by the arrangement described above, the inclination of Kolbenpleuel 4 with respect to the cylinder axis of the associated cylinder during rotation of the crankshaft 2, resulting in a reduction of the piston side forces and thus the frictional forces between the piston 2 and cylinder walls of the Cylinder leads.
• a working stroke of the pistons 3 can be selected or set as a function of a momentary power stroke of the internal combustion engine.
• the eccentric shaft 8 is driven by the crankshaft 2 via an eccentric shaft gear, not shown here.
• the eccentric shaft gear comprises at least one arranged on the eccentric shaft 8 gear element (not shown).
• crankshaft rotation angle range is an intake phase greater than 180 degrees
• a crankshaft rotation angle range of a compression phase is less than 180 degrees
• a crankshaft rotation angle range of an expansion phase is greater than 180 degrees
• a crankshaft rotation angle range is one ejection phase smaller than 180 degrees.
• FIG. 3 shows a diagram for a normal crank mechanism, in which a curve 26, the piston speed ds / da in the unit mm / rad and a curve 27, the piston speed d 2 s / da 2 in the unit mm / rad 2 , respectively above the Crankshaft angle a, represents.
• FIG. 4 shows a diagram which shows the piston speed ds / da for the multi-link crank drive in a curve 28 and the piston acceleration d 2 s / da 2 in a curve 29, also in each case above the crankshaft angle a.
• the second-order mass forces can be positively influenced in this respect. This improves the smoothness of the internal combustion engine 1, to which only the Hubverstructure, ie the course of the piston stroke on the crankshaft angle, are easily changed.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Transmission Devices (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)
• Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)

Applications Claiming Priority (2)

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ID=52013993

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• 2013
  • 2013-11-14 DE DE102013019214.5A patent/DE102013019214B3/de not_active Expired - Fee Related
• 2014
  • 2014-11-13 US US15/036,650 patent/US20160281598A1/en not_active Abandoned
  • 2014-11-13 WO PCT/EP2014/003037 patent/WO2015070980A1/de active Application Filing
  • 2014-11-13 EP EP14808830.5A patent/EP3068992A1/de not_active Withdrawn
  • 2014-11-13 CN CN201480061855.3A patent/CN105723071B/zh active Active

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