Classifications

• • 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 
  • F02F3/02—Pistons  having means for accommodating or controlling heat expansion
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J1/00—Pistons; Trunk pistons; Plungers
  • F16J1/10—Connection to driving members
  • F16J1/14—Connection to driving members with connecting-rods, i.e. pivotal connections
  • F16J1/16—Connection to driving members with connecting-rods, i.e. pivotal connections with gudgeon-pin; Gudgeon-pins
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J1/00—Pistons; Trunk pistons; Plungers
  • F16J1/10—Connection to driving members
  • F16J1/14—Connection to driving members with connecting-rods, i.e. pivotal connections
  • F16J1/20—Connection to driving members with connecting-rods, i.e. pivotal connections with rolling contact, other than in ball or roller bearings

Definitions

• the invention relates to a piston, in particular for an engine, having an upper side, a lower side, a peripheral surface running along a circumference, and a peripheral surface running essentially parallel to a course of the peripheral surface and through the upper side and through the lower side Axis of movement, wherein the peripheral surface is designed to guide the piston in a cylinder bore along the axis of movement and the top is designed to absorb compressive forces of a gas and the bottom has a connecting rod socket, the connecting rod socket having one or more undercuts in a tension and a compression direction Has undercuts, so that the connecting rod receptacle is set up to receive a thickened portion of a connecting rod that corresponds to the connecting rod receptacle, in a form-fitting manner that is pivotable about a pivot axis, with the piston having any number of radially arranged, essentially flat cross-sectional surfaces that run through the movement axis. Furthermore, the invention relates to a crank mechanism with a piston and in particular a connecting rod and
• Previous power machines that work according to the reciprocating piston principle for example diesel engines or Otto engines, usually have a piston with a piston bore arranged about a pivot axis and an associated connecting rod or an associated connecting rod rod with a corresponding bore, so that the piston and the connecting rod can be pivoted together with a so-called piston pin.
• a reciprocating internal combustion engine there is a high mass, particularly in the area of the moving masses, which negatively influences the efficiency and thus also the pollutant emissions of a corresponding engine or prevents the reduction in pollutant emissions.
• a piston is equipped with a connecting rod receptacle arranged on the underside and a connecting rod with a thickened portion that can be hooked into the connecting rod receptacle, this results in particular in better heat flow and an advantage due to less moving mass in a crank mechanism.
• thermal management of the piston is often difficult, particularly in relation to the combustion process in the engine.
• a temperature-dependent geometric behavior of the piston ie expansion when heated, must be taken into account.
• Known pistons, especially in modern diesel engines, must therefore be made oval in order to adopt a suitable, round geometry when the operating condition is warm.
• the object of the invention is to improve the state of the art .
• a piston in particular for an engine, with an upper side, a lower bottom side, a peripheral surface running along a circumference, and a peripheral surface running substantially parallel to a run of the peripheral surface and through the top and through the bottom axis of motion, the peripheral surface being configured for guiding the piston in a cylinder bore along the axis of motion, the top surface for receiving of compressive forces of a gas and the underside has a connecting rod receptacle, the connecting rod receptacle having an undercut or several undercuts in a tension and a compression direction, so that the connecting rod receptacle is set up for receiving a thickened portion of a connecting rod that corresponds to the connecting rod and can be pivoted about a pivot axis in a form-fitting manner wherein the piston has any number of radially disposed substantially planar cross-sectional areas passing through the axis of motion, wherein the piston is shaped such that a first cross-sectional area disposed radially
• a “piston” is a movable component which, together with a surrounding housing, in the case of an engine a “cylinder”, forms a closed cavity, with a volume of the cavity changing by movement of the piston in the cylinder.
• a reciprocating piston that can be moved up and down is referred to within a prismatic cylinder.
• An "upper side" of such a piston is, for example, the area of the piston referred to as the piston roof, which in an internal combustion engine faces the combustion chamber, for example. This upper side then absorbs and carries the compressive forces caused by the expanding, ignited gas mixture, as explained using the example of the internal combustion engine thus the forces necessary for the operation of the crank mechanism on the connecting rod and thus on the crankshaft.
• a “bottom” is the side of the piston facing the connecting rod or the connecting rod, ie in particular the side of the piston which has the connecting rod receptacle.
• a “circumferential surface” is the surface of the piston which, for example, faces the cylinder bore in the case of an internal combustion engine associated essentially round cylinder bore. Likewise, a correspondingly different shape of piston as well as another shape of cylinder bore can also be realized, if technically sensible.
• the peripheral surface can also typically be referred to as the boundary surface of a so-called piston skirt.
• a "axis of motion” describes the axis along which the piston is moved when a crankshaft rotates, for example.
• this axis of motion runs parallel to a central axis of a cylinder bore of the cylinder, with no mathematically exact axis in each case, but a corresponding direction is marked with technical deviations.
• a "cylinder bore" can, for example, be a cast and/or drilled cavity and then further refined, for example by honing, within an engine block of an internal combustion engine. an expansion drive or other form of prime mover, with the piston closing off the cylinder bore to a final open side, allowing compressive forces within Then allow forces to act on the piston within the cylinder bore.
• a "gas” that exerts compressive forces can either be a simple compressed gas, such as compressed air, or a gas produced by phase transition, such as superheated steam, or a gas mixture of, for example, ambient air and petrol or diesel or another fuel be f, which exerts compressive forces by ignition, for example in a gasoline or diesel engine.
• a "connecting rod receptacle" on the underside of the piston serves to hold a connecting rod in a tension-resistant and pivoting manner, so that the piston together with the connecting rod form a non-positive connection in a so-called crank drive, i.e. for example in the case of a connecting rod placed on a crankshaft of the piston with the crankshaft is made in such a way that the piston is non-positively connected to the connecting rod receptacle with the connecting rod.
• An "undercut” refers to such a design of a receptacle or a part of a receptacle in which a component or a region or partial region in the direction of force prevents pulling out in a form-fitting manner or enables a transmission of forces in a form-fitting manner.
• Such an undercut can be a surface formed by a projection, which is then used by a component attached or attached behind this undercut to transmit forces. The rod can thus be pivoted about a "pivot axis" in a form-fitting manner relative to the piston.
• a "bulge" of the connecting rod is such a region which has a larger or wider cross-section or a larger or wider diameter than a preceding part of the connecting rod.
• a thickening can serve, together with the undercut, in particular form a form-fitting, tension- or pressure-resistant connection with the surfaces formed by the undercut .
• a corresponding "cross-sectional area” refers to an essentially flat area, which results from an imaginary cutting of the piston with a cutting path along the axis of movement.
• This cross-sectional area is specified as a surface area, which is what matters in the core of the invention that this cross-sectional area is the same or similar with respect to another cross-section rotated at a rotation angle around the axis of movement.
• the reference in this comparison is the respective smallest cross-sectional area of the cross-sectional areas compared with one another, whereby an average cross-sectional area can also be used as an alternative of the piston can serve as a reference, which is determined from any number of cross-sectional areas.
• the piston is shaped in such a way that a radially arranged, essentially flat, first cross-sectional area runs through the movement axis and A radially arranged, essentially flat, second cross-sectional area running through the movement axis have a size that differs from one another by less than 7%, less than 5% and/or less than 2%.
• a first cross-sectional area and a second cross-sectional area each denote any desired cross-sectional area, i.e. in one case, for example, two cross-sectional areas in different reference axes, for example perpendicular to one another, are designed identically or similarly, so that, for example a thermal deformation behavior of the piston is controlled in the two main directions.
• the respective cross-sectional areas can run at any desired angles to one another, so that in particular a comparison of any cross-sectional areas around a circumference of the piston stands up to the correspondingly mentioned criteria.
• a piston skirt running from the top to the bottom and/or beyond the bottom is arranged on the peripheral surface, with the piston skirt in particular having a radial thickness of less than 10%, less than 5% and/or or less than 2% of a diameter of the piston.
• a corresponding compensating volume or corresponding compensating volumes can be arranged in such a way that material of the piston is applied at a point where this is not absolutely necessary from a technical point of view, so that the criteria for the size of different cross-sectional areas are met.
• a vent volume and/or several vent volumes can be removed on the upper side and/or on the underside, with the vent volume and/or the vent volumes being used to compensate for the respective cross-sectional area Volume sections of the piston is created fen t.
• a "compensation volume” describes an increase in volume, namely an additional material applied, whereas a “deduction volume” designates a correspondingly non-existent or removed material.
• an additional volume can be provided in the mold with respect to a corresponding deduction volume, with a volume corresponding to a compensating volume being removed from the mold. If the piston is produced, for example, by means of a machining process, corresponding compensating volumes or also deduction volumes can be provided directly, for example in a CNC milling program.
• the piston has a mean radius defined by a mean value of the surface area of the peripheral surface and any number of further radii running through the axis of movement and arranged radially to the axis of movement, and the piston is shaped in such a way that a any radius running along the movement axis and arranged radially to the movement axis deviates from a mean radius by less than 1%, less than 0.5%, in particular less than 1 k».
• a piston is created which has a particularly high degree of roundness, this roundness is defined, for example, by means of corresponding radii. Due to the design of the respective cross-sectional areas in a similar or even the same size, it is no longer necessary for a piston, such as a conventional piston with piston pin, to be made oval and thus thermal expansions to be taken into account in advance.
• a piston of this type as can be produced according to the invention, can therefore be produced in a particularly round manner and thus using simple production processes, for example on a lathe.
• piston rings such a particularly round piston seals well in relation to the round cylinder bore, so that no additional oil losses, blow-by losses or undesired wear occur, particularly during a cold start of an engine.
• a "mean value of the surface” describes, for example, a mean value from all possible measurement points of a surface or all calculated points of a surface of the peripheral area. This defines a “mean radius”, which, for example, is the arithmetic mean of any number of radii is formed . This mean radius serves as a reference to other radii, which define corresponding local deviations in the radii and thus deviations from the roundness of the piston.
• the piston has aluminum, an aluminum cast alloy, a a steel , a cast steel alloy and/or a [ question to the inventor : material , alloy? ] on .
• crank drive with a piston according to one of the previously described embodiments and in particular a connecting rod with a thickened portion corresponding to the connecting rod receptacle of the piston .
• crank mechanism can be provided, for example in a pre-assembly activity, in order to produce a reciprocating piston internal combustion engine with the advantages of the invention.
• the object is achieved by a reciprocating piston internal combustion engine with a piston according to one of the embodiments described above and/or with a crank drive according to the embodiment described above.
• Such a reciprocating internal combustion engine has all the advantages of the invention, for example a piston according to the invention can be used to better control corresponding tolerances between the piston and cylinder bore, thus reducing wear, oil consumption during cold starts and emissions. This applies in particular in connection with a piston with a connecting rod connected to the piston in the undercut by means of the thickening.
• FIG. 1 is a schematic representation of a crank unit with a piston and a connecting rod in an isometric view
• FIG. 2a shows the piston of the crank unit of FIG. 1 in a schematic side view
• FIG. 2b shows the piston in a schematic view from below
• Figure 2c shows the piston of Figure 2b in a sectional view A-A
• FIG. 2d shows the piston in a view from below with different sectional planes
• FIG. 3a shows the connecting rod of FIG. 1 in a schematic side view
• Figure 3b the connecting rod in an isometric
• Figure 4 in a side view, partially sectioned, from an exemplary embodiment of a crank mechanism with a piston according to the invention
• Figure 5 in a perspective view, partially sectioned, from an exemplary embodiment of a reciprocating
• a crank unit 101 has a piston 201 and a connecting rod 301 .
• the crank unit 101 is part of a diesel engine (not shown), wherein the corresponding diesel engine can have, for example, four, six or eight of these crank units, the respective pistons 201 being movably accommodated along a movement axis 281 within corresponding cylinders.
• the connecting rod 301 is held about a crank axis 185 on respective crank pins of a crankshaft designed according to the number of cylinders.
• the diesel engine is designed, for example, as an in-line four-cylinder, in-line six-cylinder or V-eight engine.
• Each is a diesel engine with high-pressure injection for diesel fuel and turbo and/or compressor charging, which results in high combustion temperatures in each cylinder.
• crank unit 101 is formed from an aluminum alloy.
• the respective connecting rod 301 is forged from steel and machined and arranged to be pivotable about a pivot axis 183 relative to the piston 201 , so that when the crankshaft rotates completely (not shown), the crank axis 185 is guided in a circular motion, the piston 201 is moved up and down in the cylinder by means of the connecting rod 301 and thus completes a complete revolution of the crankshaft without mechanical obstacles.
• On an upper side 203 of the piston 201 The gas pressure generated by the combustion of, for example, injected diesel drives the piston 201 so that overall the engine is operated according to the diesel principle.
• the injected diesel fuel is ignited by the compression of intake air in the cylinder, the compression temperature is over 700 °C and the resulting combustion temperature is over 1 . 200°C .
• the thermal influences on the piston 201 are correspondingly high.
• the piston 201 has a circumferential surface 205 and an underside 207 .
• a combustion chamber 241 with a cone-like cap 243 is arranged inside the upper side concentrically to the movement axis 281 , which enlarges the combustion chamber of the cylinder in the piston 201 .
• a predominant part of the peripheral surface 205 forms a piston skirt which runs cylindrically in the direction of the underside 207 and is thin-walled.
• the piston 201 has a narrow peripheral collar 221 which forms a distance from the top 203 to a first annular groove 223 .
• a piston ring for sealing against the cylinder is arranged within this first annular groove 223 .
• a ring groove 225 and a ring groove 227 are arranged further in the direction of the underside 207, with a further piston ring being inserted in the ring groove 225 as a sealing ring, and in the ring groove 227 a piston ring functioning as an oil scraper ring (piston rings not shown in each case).
• At the Additional bores 229 are arranged in the annular groove 227 , which facilitate the draining of engine oil.
• the peripheral collar 221 is known in diesel engines according to the prior art as a so-called "fire bridge" and is designed in these engines in the prior art with a significantly smaller diameter than the peripheral surface of a piston.
• the peripheral collar 221, on the other hand, has a radius 282 , this radius 282 being, within technical tolerances, identical to a radius 284 of the peripheral surface 205.
• the piston 201 can therefore be manufactured with regard to its cylindrical shape in a single clamping and with a single setting on a lathe.
• the peripheral collar 221 can be designed in this form, since the usual function of a "top land" of the prior art, namely additional heat dissipation via this top land through a thinner diameter and thus access for the combustion gases in the piston 201, can be omitted Explanations on this are given below.
• the piston 201 has a receptacle 210 for the connecting rod 301 .
• the receptacle 210 is essentially formed by an undercut 211 which has an inner surface 213 arranged concentrically around the pivot axis 183 and is delimited by a respective edge 217 .
• the piston skirt 219 on both sides along the pivot axis 183 on a cutout 220 Through this cutout 220, both the connecting rod 301 can be pushed into the piston 201, and during the previous production of the piston 201, a corresponding tool for fine machining the inner surface 213 can be introduced without obstacles.
• the piston 201 has different volumes.
• the piston 201 has a respective symmetrical to the movement axis 281 arranged thickenings 231, pockets 233 also arranged symmetrically to the movement axis 281, and additional thickenings 235 arranged symmetrically to the movement axis 281 and in the direction of the pivot axis 183.
• the corresponding volumes of the thickenings 231, the pocket 233 and the thickenings 235 are selected in such a way that any cut surfaces formed by the movement axis 281, namely, for example, cut surfaces formed along a cutting plane 271, a cutting plane 273 or a cutting plane 275 (also compare FIG. 2d) , are each equal in area with a tolerance of, for example, 2% in relation to a respective smallest of the compared cut surfaces.
• This geometric design ensures that the thermal expansion behavior of the col bens 201 is almost identical or even identical in different polar positions around the movement axis 281 .
• material is applied to the thickened portion 231 , material is removed from the pocket 233 and material is applied to the thickened portion 235 .
• a respective thickening 235 also serves, for example, to at least partially equalize the missing material in the piston skirt 219 at the cutout 220 to form corresponding cross-sectional areas.
• other components are compensated analogously by subtracting or adding corresponding volumes of the material of the piston 201 .
• annular grooves 215 are introduced along the pivot axis 183 on both sides symmetrically to the movement axis 281 , these annular grooves being designed as partial annular grooves 215 due to the shape of the undercut 211 .
• the respective annular groove 215 has a cross section starting from a diameter 216 of the inner surface 213 up to a diameter 218 .
• the connecting rod 301 has a connecting rod head 303 , a central area 305 and a crankshaft connection 307 .
• the connecting rod head is designed as a thickening with a cylindrical outer surface 311 .
• the outer surface 311 corresponds to the diameter 216 of the inner surface 213 of the piston 201, taking into account the necessary tolerances.
• chamfers 312 are arranged in the end regions of the thickening in the direction of the pivot axis 183 . So he can Connecting rod head 303 is pushed into piston 201 along pivot axis 183, so that a pivot joint with freedom of movement about pivot axis 183 is formed.
• the middle area 305 connects the connecting rod head 303 to the crankshaft connection 307 and has a depression 306 on both sides along its extension between the connecting rod head 303 and the crankshaft connection 307, so that overall a rigid cross-section of the middle area 305 according to a double T-beam is formed .
• webs 315 with recesses 316 formed in relation to the central region 305 are arranged in such a way that the central region 305 is additionally rigidly connected with respect to the crankshaft connection 307 and yet is as light as possible.
• crankshaft connection 307 is made up of a part of the connecting rod 301 and a so - called cover 308 , with the crankshaft boss 309 being formed together , which is arranged concentrically around the crank axis 185 .
• the crankshaft boss 309 is provided with a bearing shell 321 in order to produce a low-friction, wear-resistant connection to the crankshaft that is able to run in an emergency.
• the bearing shell is arranged in the crankshaft boss 309 so that it cannot rotate, so that the position of the bearing shell 321 in relation to the connecting rod 301 is rotationally fixed.
• the connecting rod 301 has a valve groove 341 on the outer surface 311 of the connecting rod head 303 , which is connected to an outlet opening 343 .
• the outlet opening 343 is part of an oil channel 345 which is located between the outlet opening 343 and an inside of the Crankshaft eye 309 arranged inlet opening 347 runs.
• the oil channel 345 is arranged in the neutral line of the middle area 305, so that the oil channel 345 weakens the middle area 305 as little as possible, in particular against bending.
• the connecting rod head 303 is pushed into the undercut 211 along the pivot axis 183 .
• An elastic locking ring with a round wire cross-section is inserted inside the annular groove 215 in such a way that a part of the locking ring (not shown) extends into the cross-section of the undercut 211 formed by the inner surface 213 .
• This circlip is then pushed back into the annular groove by means of the chamfer 312 on the connecting rod head 303 , the cross section of the circlip being selected such that it can be positioned completely between the diameter 216 and the diameter 218 .
• the chamfer 312 thus facilitates the insertion of the connecting rod head 303 into the piston 201 . If the connecting rod head 303 is pushed in completely symmetrically, a corresponding locking ring springs back into its initial position and secures the connecting rod 301 on the connecting rod head 303 against unintentional removal along the pivot axis 183 .
• crank unit 101 The function of the crank unit 101 with regard to the lubrication of the connection between the connecting rod head and the piston 201 in the undercut 211 is explained as follows:
• crankshaft Within the crankshaft (not shown) there is a bearing point for lubricating the crankshaft Oil duct running inside the crankshaft with corresponding outlet bores provided at the bearing points.
• the crankshaft also has corresponding outlet bores for pressurized engine oil on the crank pins, which accommodate the respective connecting rod 301 around the crank axis 185 .
• the engine oil is then held in a circumferential annular groove on the crankshaft and presses through the inlet opening 347 into the oil channel 345 to the outlet opening 343 . With the outlet opening 343 and the valve groove 341, an oil reservoir is created, in which pressurized engine oil is available for lubricating the undercut 311.
• valve groove 341 serves to control the oil flow depending on a position of the crankshaft and a resulting position of the connecting rod 301 and the piston 201 .
• the connecting rod 301 is essentially vertical within the cylinder bore along the movement axis 281 .
• the valve groove 341 is completely surrounded by the inner surface 213 of the undercut 211, so that no oil can escape through the valve groove 341.
• the oil cushion in the oil reservoir also prevents direct material contact.
• FIG. 4 shows a side view, partially sectioned, of an exemplary embodiment of a crank mechanism according to the invention, the crank mechanism comprising a piston 201 according to one of the exemplary embodiments described above and a corresponding connecting rod 301 - i.e. a crank unit 101 - and a crankshaft 401.
• the connecting rod 301 is coupled to the crankshaft 401 in a conventional manner.
• the piston 201 can be moved in a cylinder arrangement 501 along a movement axis 281 .
• Figure 5 shows a perspective and partially sectioned view - in a detail - an embodiment of a reciprocating internal combustion engine 601 with a cylinder arrangement 501 with four cylinders to form an in-line four-cylinder engine and with pistons 201 and connecting rods 301 according to one of the above From examples .
• a piston 201 and a connecting rod 301 each form a crank unit 101 .
• the connecting rod 301 is coupled to a crankshaft 401 .
• the geometric configuration of the piston 201 also optimizes the heat dissipation, as explained above.
• the central connection of the el rod 301 in the receptacle 210 of the piston 201 enables good heat conduction, so that the "fire bridge" known from the prior art can also be omitted.
• an easy-to-manufacture and also very efficient fi cient diesel engine can be provided.
• the diesel engine can be operated with high combustion temperatures and thus low-emission and efficient combustion because of the geometry of the piston 201, the compact design and central dissipation of heat into the connecting rod 301 and the controlled oil flow of the engine oil good heat management is ensured.
• the combination of piston 201 and connecting rod 301 according to the invention therefore has a very low weight and thus reduced moving masses. It should be noted that although this type of piston 201 and connecting rod 301 was shown in the present example for a diesel engine with high-pressure injection and supercharging, the corresponding arrangement of piston 201 and connecting rod 301 is also suitable for other reciprocating machines, for example Otto engines, compressors or diesel engines.

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

Applications Claiming Priority (2)

Publications (1)

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• 2021
  • 2021-12-23 DE DE102021134520.0A patent/DE102021134520A1/de active Pending
• 2022
  • 2022-12-22 US US18/710,350 patent/US20250012230A1/en active Pending
  • 2022-12-22 EP EP22843805.7A patent/EP4453401A1/de active Pending
  • 2022-12-22 KR KR1020247024414A patent/KR20240123378A/ko active Pending
  • 2022-12-22 JP JP2024537119A patent/JP2024546292A/ja active Pending
  • 2022-12-22 WO PCT/EP2022/087653 patent/WO2023118533A1/de not_active Ceased

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