WO2018199024A1 - Piston de moteur à combustion interne et procédé de fabrication de piston de moteur à combustion interne - Google Patents

Piston de moteur à combustion interne et procédé de fabrication de piston de moteur à combustion interne Download PDF

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Publication number
WO2018199024A1
WO2018199024A1 PCT/JP2018/016463 JP2018016463W WO2018199024A1 WO 2018199024 A1 WO2018199024 A1 WO 2018199024A1 JP 2018016463 W JP2018016463 W JP 2018016463W WO 2018199024 A1 WO2018199024 A1 WO 2018199024A1
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Prior art keywords
piston
combustion engine
internal combustion
engine according
layer
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PCT/JP2018/016463
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English (en)
Japanese (ja)
Inventor
一等 杉本
直也 沖崎
和也 野々村
助川　義寛
高橋　智一
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日立オートモティブシステムズ株式会社
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Publication of WO2018199024A1 publication Critical patent/WO2018199024A1/fr

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    • 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 
    • 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 
    • F02F3/10—Pistons  having surface coverings
    • 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 
    • F02F3/10—Pistons  having surface coverings
    • F02F3/12—Pistons  having surface coverings on piston heads
    • F02F3/14—Pistons  having surface coverings on piston heads within combustion chambers
    • 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
    • F16J1/01—Pistons; Trunk pistons; Plungers characterised by the use of particular materials

Definitions

  • the present invention relates to a piston for an internal combustion engine and a method for manufacturing a piston for an internal combustion engine.
  • Patent Document 1 a heat insulating layer is provided on the surface of a member facing the engine combustion chamber, and the heat insulating layer is made of a hollow particle made of an inorganic oxide, a filler material, and a vitreous mainly composed of silicic acid.
  • a structure is disclosed in which the vitreous material is in a non-finished state, covering the hollow particles and the filler material, and bonding.
  • the hollow particles can improve the heat insulating performance of the heat insulating layer, prevent the penetration of fuel into the heat insulating layer, and maintain high heat insulating properties over a long period of time. .
  • the metal and ceramics (glass) which comprise the conventional heat insulation layer have a large volumetric specific heat
  • the base temperature of the base material constituting the engine the temperature of the base material when the gas temperature in the combustion chamber is the lowest
  • the thermal responsiveness (followability) of the temperature of the combustion chamber wall surface with respect to the gas temperature decreases.
  • the thermal response is low, becomes a cause of increase in knocking and NO x, the fuel combustion efficiency is lowered. Therefore, the heat insulating layer having a large volume specific heat is not provided on the entire surface of the internal combustion engine member constituting a part of the wall surface of the combustion chamber, and needs to be used in a limited range.
  • a heat insulating layer that can be used in a larger area is required on the combustion chamber wall surface.
  • a material constituting the heat insulating layer in addition to low thermal conductivity, low What has a volume specific heat is calculated
  • Patent Document 2 discloses a heat insulating film composed of an anodized film having a porous structure including a large number of pores, and a plurality of particles enclosed in the pores of the heat insulating film, and adjacent particles.
  • An internal combustion engine is disclosed that includes a plurality of encapsulated particles that are encapsulated so that a gap between them becomes a gap of a preset size.
  • Patent Document 2 describes that the heat insulating film uses a heat insulating material having a lower thermal conductivity and a lower heat capacity per unit volume than the base material, and a heat insulating material having a hollow structure is used as the material. It is described that it is suitable.
  • the heat insulating layer has both low thermal conductivity and low volume specific heat.
  • Patent Document 1 and Patent Document 2 described above all achieve sufficient levels for all items of porous porosity, durability, adhesion to a substrate, low thermal conductivity, and low volume specific heat. It was not a thing.
  • the present invention provides a piston for an internal combustion engine having a porous structure capable of ensuring adhesion and durability with a substrate and realizing low thermal conductivity and low volume specific heat. It aims at providing the manufacturing method of a piston.
  • an insert having a base material and a sintered layer provided on the base material, and having a lower melting point than the piston base material between the sintered layer and the base material. It was set as the structure which has the osmosis
  • the method for manufacturing a piston for an internal combustion engine according to the present invention includes a method of forming a permeation diffusion layer by using a metal having a melting point lower than that of the base material as an insert material, and the insert material permeates the pores of the sintered body. did.
  • the manufacturing method of the piston for internal combustion engines which can ensure the adhesiveness and durability with a base material, and can implement
  • FIG. (A) is a perspective view which shows typically an example of the piston which concerns on this invention
  • (b) is the sectional view on the AA 'line of (a).
  • (A) shows the enlarged view of the cross section of the crown surface 101 of the piston 100 which concerns on this invention
  • (b) is an enlarged view of the metal particle 32 which comprises the metal layer 30 of Fig.2 (a).
  • 6 is a cross-sectional view schematically showing an example of a sintered layer constituting a piston according to Example 2.
  • FIG. (A) is sectional drawing which shows the 1st example of the piston concerning this invention
  • (b) is sectional drawing which shows the 2nd example of the piston concerning this invention
  • (c) is 3rd of the piston concerning this invention.
  • FIG. 6 is a cross-sectional view schematically showing an example of a sintered layer constituting a piston according to Example 3.
  • FIG. It is a flowchart which shows an example of the manufacturing method of the sintered layer 2 used for the piston which concerns on this invention. It is a flowchart which shows an example of joining with the base material 1 and the sintered layer 2 of the piston which concerns on this invention.
  • FIG. 10 is a flowchart showing another example of the method for manufacturing the piston according to the second embodiment. It is a figure which shows an example of a pulse electricity supply apparatus typically.
  • (A) is a cross-sectional SEM observation photograph of a hollow particle according to Experimental Example 1
  • (b) is a cross-sectional SEM observation photograph of the sintered layer 2 according to Experimental Example 1
  • (c) is an enlarged photograph of (b), (d).
  • (A) is a graph showing the relationship between the output of laser light and time in the thermal response evaluation test of the experimental example
  • FIG. 10 (b) shows the relationship between the surface temperature of the test piece and time in the thermal response evaluation test of the experimental example. It is a graph to show.
  • FIG. 1A is a perspective view schematically showing an example of a piston according to the present invention
  • FIG. 1B is a cross-sectional view taken along the line AA ′ of FIG.
  • the piston 100 for an internal combustion engine according to the present invention (hereinafter also simply referred to as “piston”) has a crown surface 101 on the upper surface and a piston receiving portion 102 on the side surface.
  • the crown surface 101 is a part which becomes a part of the inner wall of the combustion chamber, and is a part where a heat insulating layer is provided in order to improve combustion efficiency.
  • a “surface layer” having both low thermal conductivity and low volume specific heat characteristics is provided on the crown surface (surface) of the piston 100.
  • this surface layer will be described in detail.
  • FIG. 2A shows an enlarged view of a cross section of the crown surface 101 of the piston 100 according to the present invention.
  • the crown surface 101 of the piston 100 according to the present invention includes a piston base material 1 (hereinafter simply referred to as “base material”) and a firing provided on the surface of the base material 1. It has a tie layer 2.
  • the sintered layer 2 includes a metal layer 30 formed by bonding a plurality of metal particles and a void surrounded by a portion other than the bonded portion of the metal particles (in other words, a void formed between the metal particles). ) 31.
  • the metal layer 30 is composed of a sintered metal in which metal particles are bonded by sintering.
  • the metal layer 30 and the gap 31 are collectively referred to as a parent phase 3.
  • FIG. 2 (b) is an enlarged view of the metal particles 32 constituting the metal layer 30 of FIG. 2 (a).
  • FIG. 2B it is preferable that some of the metal particles 32 are bonded together by sintering and have a neck 33.
  • the space between the metal particles 32 can be secured by the neck 33 and the gap 31 can be formed.
  • the ratio of the voids 31 can be controlled by controlling the sintering density. A method for producing such a sintered metal will be described later.
  • the permeation diffusion layer 4 is a layer in which an insert material having a melting point lower than that of the base material is dissolved in a part of one side of the matrix 3 and is permeated and diffused, and a part of the void 31 provided in the original sintered body. Is buried by absorbing the insert material.
  • FIG. 2A shows a structure in which the parent phase 3 exists up to the BB part.
  • permeation diffusion layer 4 contain the same metal as each main component.
  • the base material 1 is preferably an aluminum (Al) alloy
  • the permeation diffusion layer 4 is preferably an Al alloy.
  • the permeation diffusion layer 4 and the sintered layer 2 preferably contain the same metal as their main component.
  • the metal layer 30 that constitutes the main part of the permeation diffusion layer 4 and the sintered layer 2 With the same metal, a solid phase bonded portion can be formed at the interface between the permeation diffusion layer 4 and the sintered layer 2 having a porous structure. It is possible to provide the sintered layer 2 which is formed to ensure adhesion and is excellent in durability.
  • the volume specific heat of the sintered layer 2 is preferably 1000 kJ / m 3 ⁇ K or less.
  • the thermal conductivity is preferably 1 W / mK or less.
  • the piston 100 there is no particular limitation as long as the above-described sintered layer 2 is formed on the crown surface 101 of the piston 100.
  • the example of the location which forms the sintered layer 2 in the piston 100 is shown below.
  • FIG. 4A is a cross-sectional view showing a first example of the piston according to the present invention, in which a concave portion is provided on the crown surface 101 of the piston 100, and the sintered layer 2 is arranged in the concave portion.
  • FIG. 4B is a sectional view showing a second example of the piston according to the present invention, in which the sintered layer 2 is disposed on the entire crown surface 101.
  • FIG. 4C is a cross-sectional view showing a third example of the piston according to the present invention, in which a recess is provided along the shape of the crown surface 101, and the sintered layer 2 is disposed in the recess 101. is there.
  • the place where the sintered layer 2 is formed is not particularly limited, and as shown in FIG. It may be formed, may be formed on the entire surface of the crown surface 101 as shown in FIG. 4B, and has a thickness along the surface shape of the sintered layer 2 on the crown surface 101 as shown in FIG. You may form so that may become constant.
  • FIG. 6A is a flowchart showing an example of a method for producing the sintered layer 2 used in the piston according to the present invention
  • FIG. 6B shows the substrate 1 and the sintered layer 2 of the piston according to the present invention. It is a flowchart which shows an example of joining.
  • the metal particles 32 as the raw material of the metal layer 30 and the powder of the hollow particles 5 are mixed (S10: metal particle powder (raw material mixed powder) preparation step).
  • S10 metal particle powder (raw material mixed powder) preparation step
  • S11 sintered
  • S12 sintered body
  • the method for sintering the mixed powder is not particularly limited as long as it is a method capable of sintering metal particles so that voids 31 are formed in the mother phase 3, but pulse current sintering, hot press sintering, Isotropic pressure sintering and cold isotropic pressure sintering are preferred. Among these, it is preferable to use pressure sintering capable of controlling the load and temperature, and the pulse current sintering method is preferable.
  • Pulse electric current sintering Pulse Electric Current Sintering
  • spark Plasma Sintering spark plasma sintering
  • the reaction on the powder surface is activated, so that sintering in an environment with a relatively small load is possible.
  • the parent phase 3 It is possible to control the ratio of the voids 31 of the above.
  • FIG. 6B a piston base material is produced by casting (S13).
  • a rough material of a piston base material made of an Al alloy is cast by a conventional method.
  • machining laand part outer diameter cutting, pin hole machining, etc.
  • an insert material having a low melting point is placed on the surface of the substrate (S14a).
  • the sintered body produced in the process shown in FIG. 6A is placed in contact with the surface of the substrate (S15).
  • the base material and the sintered body are joined (S16).
  • a joining method a technique is preferred in which the insert material is heated and melted, diffused between the sintered body and the base material, and in particular, permeated and diffused into the voids of the sintered body.
  • the heating method include, but are not limited to, heat treatment, friction stir welding, laser welding, arc welding, and the like.
  • a heat treatment step is performed (S17). This heat treatment is intended to remove strain generated in the joining process and make the strength uniform. For example, solution aging treatment or artificial aging treatment is performed. After the heat treatment step, finishing machining is performed as a secondary machining step (S18), and the product piston is completed (S19).
  • Example 2 will be described.
  • This embodiment is different from the first embodiment in that the hollow particles 5 are arranged inside the matrix phase 3.
  • the hollow particles 5 are contained in the voids 31 of the matrix 3 and the voids 31 of the matrix 3 and the voids 50 of the hollow particles 5 are combined, whereby the porosity of the sintered layer 2 as a whole.
  • the strength of the sintered layer 2 was maintained while ensuring sufficient.
  • FIG. 3 is a cross-sectional view schematically showing a case where the hollow particles 5 are included in the parent phase 3 as described above, and the hollow particles 5 are included in the parent phase 3.
  • the hollow particles 5 are particles having pores (fine pores) 50 inside.
  • a combination of the voids 31 included in the matrix 3 and the voids 50 included in the hollow particles 5 is a volume ratio of voids (hereinafter referred to as “porosity”) occupying the sintered layer 2.
  • the porosity of the entire sintered layer 2 is increased to 50% by volume by combining both the void 31 of the matrix 3 and the void 50 of the hollow particle 5.
  • hollow particles 5 are also included in the permeation diffusion layer 4. If the hole 50 of the hollow particle 5 is a closed hole, an insert material does not enter and the hole is maintained as it is. Further, even if the hole 50 is an open hole, the insert material is less likely to enter compared to the gap 31, and the hole remains. As a result, the permeation diffusion layer 4 has a structure having pores and a structure having a lower porosity than the sintered layer 2.
  • various porous oxides such as silica (SiO 2 ), alumina (Al 2 O 3 ), and zirconia (ZrO 2 ) can be used, but in order to ensure the heat insulating performance of the sintered layer 2. It is preferable to use a material having a low thermal conductivity, and it is particularly preferable to use silica.
  • Silica has a relatively low thermal conductivity among ceramics and is a material having a relatively high strength even when hollow.
  • the hollow particles mainly composed of silica include ceramic beads, silica airgel, porous glass, glass beads, volcanic white sand, diatomaceous earth, and processed powders thereof, but are not limited thereto.
  • the particle diameter of the metal particles constituting the metal layer 30 and the particle diameter of the hollow particles 5 are preferably substantially the same.
  • the particle diameter of the hollow particles 5 is larger than the particle diameter of the metal particles 32, the bonds between the metal particles 32 are hardly formed, and the strength of the metal layer 30 that is a sintered body may be reduced.
  • the particle diameter of the hollow particles 5 is smaller than the particle diameter of the metal particles 32, there is a possibility that the formation of the voids 31 between the metal particles 32 is hindered and a high porosity cannot be realized. Therefore, in this embodiment, the particle diameter of the metal particles 32 and the particle diameter of the hollow particles 5 are substantially the same.
  • FIG.6 (c) is a flowchart which shows another example of the manufacturing method of the piston which concerns on a present Example.
  • the insert material or the mixed powder may be powdered and placed on the surface of the substrate 1, but the powder is preliminarily formed by applying pressure to a molded body having a predetermined shape, for example, powder.
  • the green compact may be pressed into a biscuit shape and placed on the surface of the base material 1 (piston crown surface).
  • the pulse current sintering method was used as in Example 1.
  • the reaction on the powder surface is activated, it is possible to sinter in an environment where the load is relatively small, and the shape of the hollow particles can be contained without breaking.
  • a metal layer (sintered metal) 30 in which the metal particles are connected to each other is formed, and the void 31 is formed in a portion other than the joint portion between the metal particles.
  • the hollow particles 5 can be included without breaking the shape.
  • the porosity of the sintered layer 2 is not particularly limited but is preferably 50% or more.
  • Example 3 will be described.
  • This embodiment is different from the second embodiment in that a sealing layer 51 made of a sealing material is provided on the surface of the sintered layer 2.
  • FIG. 5 is a cross-sectional view schematically showing an example of a sintered layer constituting the piston according to the present embodiment.
  • the gap 31 is sealed on the surface of the sintered layer 2 with a sealing layer 51 made of a sealing material, and the fuel soaks into the back of the sintered layer 2 (base 1 side). It is preferable to prevent this.
  • the sealing layer 51 is provided on the surface of the sintered layer 2
  • the sealing material is not only the surface of the sintered layer 2 (portion indicated by 52 in FIG. 5), but also the gap 31 (53 in FIG. 5) near the surface.
  • the sintered layer 2 secures the porosity of the entire sintered layer 2 with the voids 31 of the parent phase 3 and the pores 50 of the hollow particles 5. Since the sealing material does not enter the pores 50 inside the particles 5, even if a part of the void 31 of the mother phase 3 is sealed by the sealing material, the entire sintered layer 2 is sufficient. The porosity can be ensured.
  • sealing material examples include, but are not limited to, polysilazane, polysiloxane, silica alkoxide, polyamide, polyamideimide, polyimide, and various resins.
  • a piston having an excellent thermal response characteristic and having a structure that can withstand long-term use, and assists in combustion of fuel to contribute to improvement of fuel consumption of the internal combustion engine. It also contributes to suppressing deposits and smoke emissions from the internal combustion engine.
  • the sealing material forming step is the step of joining the sintered body and the base material (S16 or S16 ′) in the steps of FIGS. 6B and 6C described in the first and second embodiments and the heat treatment step. (S17) or the secondary machining process (S18) is performed between the processes.
  • the sealing layer 51 may be formed before the heat treatment step (S17), may be formed before the secondary machining step (S18), or the secondary machining step (S18). It may be formed later.
  • a heat treatment process may be further added to fix the applied sealing material on the piston surface. Further, the heat treatment step (S17) may also serve as drying of the sealing material after application.
  • the sealing layer 51 for example, when polysilazane is used as a sealing material, a coating solution containing a polysilazane precursor is applied to the surface of the sintered body, and dried by heating at 400 to 500 ° C. for 1 to 2 hours. By doing so, it can be formed.
  • a base material was prepared as if it were a piston crown surface, and test pieces having a surface layer in which the ratio of hollow particles was changed on the surface thereof were prepared (Experimental Examples 1-3, Reference Examples 1 and 2).
  • the obtained test piece was evaluated for its sintered state, porosity and thermal responsiveness.
  • a disk-shaped test piece (diameter: 75 mm, thickness: 10 mm) was prepared using an Al alloy (JIS (Japan Industrial Standards) 4032-T6) close to the actual piston material. A recess having a thickness of 5 mm was formed.
  • JIS Japanese Industrial Standards
  • a raw material mixed powder constituting the sintered layer 2 (a raw material powder for the surface layer)
  • a raw material mixed powder prepared by mixing Al particles as the metal particles 32 constituting the metal layer 30 and SiO 2 particles as the hollow particles 5 was prepared. All particles were prepared with an average particle size of 30 ⁇ m.
  • This raw material mixed powder was sintered by a pulse current sintering method to produce a sintered body.
  • FIG. 7 is a diagram schematically showing an example of the pulse energization device used in the examples.
  • the above-mentioned mixed powder sintered layer raw material powder 61
  • the carbon punch 63 is driven in the direction of the arrow in FIG.
  • a pulse energization was applied to the mixed powder through 67 and the electrodes (upper electrode 65 and lower electrode 66), and the mixture was heated and sintered.
  • the temperature, the load and the indentation amount of the carbon punch 63 were monitored.
  • the obtained sintered body was processed so as to have a shape with a diameter of 30 mm and a thickness of 3 mm, and placed in the recess of the aluminum alloy test piece described above.
  • the sintered body and the aluminum alloy test piece were fixed using a restraining jig, and both were diffusion-bonded by heating in a heat treatment furnace.
  • Reference Example 1 uses pure aluminum having a melting point lower than that of a sintered body as an insert material in joining of sintered layers according to the present invention.
  • Reference Example 2 is a test piece made of only an aluminum base material having no sintered layer.
  • Table 1 the porosity P of the sintered layer and the porosity Q of the permeation diffusion layer were calculated from the following formulas (1) and (2), respectively.
  • D m is the measured density (g / cm 3 ), and was calculated by measuring the volume and weight from a rectangular parallelepiped piece taken from the test piece.
  • D i is the ideal density of the bulk material does not contain pores (g / cm 3), was determined in consideration of the content ratio of the metal particles (Al) hollow particles (SiO 2).
  • ⁇ is the volume ratio of the remaining portion of the voids of the sintered body, and ⁇ is the portion of the void portion of the hollow particle remaining. Volume ratio.
  • X is a volume ratio indicating the ratio of voids of the sintered body in the pores of the original sintered layer
  • 1-X is a volume ratio indicating the ratio of voids of the hollow particles.
  • hole in a hollow particle can be measured with the true density meter using helium gas, The average ratio of the void
  • FIG. 8A is a cross-sectional SEM observation photograph of the hollow particles according to Experimental Example 1
  • FIG. 8B is a cross-sectional SEM observation photograph of the sintered layer 2 according to Experimental Example 1
  • FIG. FIG. 8B is an enlarged photograph
  • FIG. 8D is an optical micrograph observing a cross section of the surface layer portion including the sintered layer 2 and the permeation diffusion layer.
  • the white portion is Al
  • the gray portion is SiO 2
  • the black portion is voids and holes.
  • FIGS. 8B and 8C it can be seen that in the sintered layer, the hollow silica 72 is contained in the void 73 formed between the Al particles 71 while maintaining its shape.
  • the sintered bodies used in Experimental Examples 1 to 3 and Reference Example 1 were made of a porous sintered body using a raw material containing 50% by volume of hollow silica so that the void ratio during sintering was 32% by volume. .
  • the ratio x of voids in the sintered layer was 0.59.
  • the bonding temperature was 470 ° C. as the temperature at which the aluminum base material was not softened.
  • Example 1 In Examples 1 to 3 in which an aluminum alloy powder having a melting point lower than that of aluminum was used as an insert material, a good bonding state could be secured by forming a permeation diffusion layer, whereas a reference using pure aluminum powder as an insert material In Example 1, the insert material was fixed in a sintered state without melting, and the permeation diffusion layer was not formed.
  • FIG. 9 is a schematic diagram of an apparatus used in a thermal responsiveness evaluation test of an experimental example. As shown in FIG. 9, the evaluation apparatus irradiates a test piece 81 installed in a vacuum chamber 82 with a laser beam using a laser heat source 84, and determines the surface temperature of the test piece 81 at that time using an infrared camera. 83 is used for measurement.
  • FIG. 10A is a graph showing the relationship between laser light output and time in the thermal response evaluation test of the experimental example
  • FIG. 10B is a graph showing the surface temperature and time of the test piece in the thermal response evaluation test of the experimental example. It is a graph which shows a relationship.
  • FIG. 10B shows the surface temperature at the time of laser irradiation in FIG.
  • the peak temperature recorded at the first laser irradiation is T 1
  • the peak temperature recorded at the third laser irradiation is T 3 .
  • Laser irradiation was carried out by applying a black body paint for absorbing laser to the test piece.
  • the thermal response evaluation test to simulate the First engine environment, as the peak temperature T 1 of the aluminum test piece of Reference Example 2 provided with no surface layer, the 200 ° C. approximately close to the actual engine environmental, Laser irradiation conditions were selected. Specifically, as shown in FIG. 10 (a), an 800W laser was irradiated for 1 second and naturally cooled for 5 seconds was set as one set, and a total of 3 sets of irradiation were performed. Since the upper limit of the temperature that can be quantitatively evaluated by the infrared camera 83 is 500 ° C., when it exceeds 500 ° C., it is described as “over 500 ° C.”. In order to instantly burn the fuel at the piston crown surface, it is necessary to heat to about 400 ° C.
  • a piston having a surface layer having the same configuration as Experimental Example 1 was manufactured by the method shown in FIGS. 6 (a) and 6 (b).
  • the sintered body was produced in the same manner as in Example 1 by the pulse current sintering method according to the manufacturing process of FIG. 6A, and was processed into a diameter of 70 mm and a thickness of 3 mm.
  • primary machining S14 is applied to the aluminum alloy piston rough material (JIS AC8A) produced in the piston casting process (S13). A recess having a diameter of 70 mm was formed.
  • a powder that serves as an insert material is laid in the recess, a pre-sintered sintered body is placed in the recess of the piston crown surface, and the sintered body and the piston base material are sufficiently brought into contact with a restraining jig (S15), and a heat treatment furnace Was joined (S16). Thereafter, solution treatment and artificial aging treatment (S17) were performed, and a piston having a predetermined shape was fabricated by processing into a finished shape by secondary machining (S18) (S19). This piston is referred to as Experimental Example 4.
  • the sealing layer formation process was implemented with respect to the piston surface after the secondary machining (S18) with respect to the piston produced by the said method. Specifically, after secondary machining (S18), polyamide imide was applied to the piston crown surface and subjected to a dry heat treatment so that voids near the surface were sealed. However, the pores originally contained in the hollow silica have a closed structure and remain as pores.
  • This piston is referred to as Experimental Example 5.
  • Example 7 in which the sealing layer is provided, higher combustion efficiency can be realized by preventing the fuel from entering the voids in the surface layer. It was confirmed that the sealing layer contributes to fuel efficiency.
  • a piston 100 for an internal combustion engine according to the present invention includes a base material 1 and a sintered layer 2 provided on the base material 1, and the base material 1 is interposed between the sintered layer 2 and the base material 1.
  • a permeation diffusion layer was formed on the sintered body side with an insert material having a melting point lower than that of (1).
  • the metal that is the main component of the permeation diffusion layer 4 and the sintered body 2 is aluminum, and the main component of the base material is also aluminum.
  • the base layer 1, the permeation diffusion layer 4 and the metal layer 30 constituting the main part of the sintered layer 2 can be composed of the same metal, and the base layer 1 and the permeation diffusion having a porous structure. It is possible to form a solid phase bonded portion at the interface between the layer 4 and the sintered layer 2 to ensure adhesion, and to make the sintered layer 2 excellent in durability.
  • the piston 100 for an internal combustion engine according to the present invention includes hollow particles 5 in the sintered body 2.
  • the strength of the sintered layer 2 can be increased while ensuring the porosity of the entire sintered layer 2 by combining the voids 31 in the matrix 3 and the voids 50 of the hollow particles 5. It becomes possible to keep.
  • the sintered body 2 preferably has a porosity of 50% or more.
  • the insert material includes at least an aluminum alloy.
  • the aluminum alloy contained in the insert material is an Al—Mg alloy.
  • the Al—Mg alloy contained in the insert material is Al 12 Mg 17 .
  • the thickness of the permeation diffusion layer is at least twice the average particle diameter of the metal particles contained in the sintered body.
  • the porosity of the permeation diffusion layer is lower than that of the sintered body.
  • the porosity of the permeation diffusion layer may be inclined.
  • the volume specific heat of the sintered layer is 1000 kJ / m 3 ⁇ K or less, and the thermal conductivity is 1 W / mK or less.
  • the thickness of the sintered layer is preferably 50 ⁇ m or more and 100 ⁇ m or less.
  • a metal having a melting point lower than that of the base material is used as the insert material, and the insert material penetrates into the pores of the sintered body to form the permeation diffusion layer. It is characterized by.
  • the method for manufacturing a piston for an internal combustion engine uses a pulse current joining method when the insert material is melted and joined.
  • the method for manufacturing a piston for an internal combustion engine according to the present invention may use an external heat source when the insert material is melted and joined.
  • the insert material is powder.
  • the powder of the insert material contains an Al alloy.
  • Al contained in the insert material is an Al—Mg alloy.
  • the Al—Mg alloy contained in the insert material is Al 12 Mg 17 .
  • the insert material is a sheet-like material.
  • the sheet material of the insert material contains an Al alloy.
  • the piston for an internal combustion engine according to the present invention can ensure durability and adhesion to the base material, and can realize low thermal conductivity and low volume specific heat. It was done.
  • this invention is not limited to the above-mentioned Example, Various modifications are included.
  • the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described.
  • a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment.
  • DESCRIPTION OF SYMBOLS 1 Base material, 2 ... Sintered layer, 3 ... Mother phase, 30 ... Metal layer, 31 ... Void, 32 ... Metal particle, 33 ... Neck, 4 ... Penetration diffusion layer, 5 ... Hollow particle, 50 ... Hole, DESCRIPTION OF SYMBOLS 51 ... Sealing layer, 52 ... Sealing material on the surface of a sintered layer, 53 ... Sealing material which penetrate
  • Pulse power supply 71 ... Al particle, 72 ... Hollow silica, 73 ... Air gap, 81 ... Test piece, 82 ... Vacuum chamber, 83 ... Infrared camera, 84 ... Laser heat source, 100, 100a, 100b, 100c ... piston, 101 ... piston crown surface, 102 ... piston pin receiving part

Landscapes

  • 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)

Abstract

L'invention concerne un piston de moteur à combustion interne ayant une structure poreuse avec laquelle à la fois l'adhérence à un matériau de base et la durabilité peuvent être maintenues, et avec laquelle une faible conductivité thermique et une faible chaleur spécifique volumétrique peuvent être obtenues. La présente invention concerne également un procédé de fabrication d'un piston de moteur à combustion interne. L'invention concerne un piston de moteur à combustion interne caractérisé en ce qu'il comprend un matériau de base (1) et une couche frittée (2) disposée sur une surface du matériau de base, une couche de diffusion de pénétration (4) formée au moyen d'un matériau d'insert ayant un point de fusion inférieur à celui du matériau de base étant disposée entre la couche frittée et le matériau de base. L'invention concerne également un procédé de fabrication d'un piston de moteur à combustion interne, caractérisé en ce que : un corps empilé est fabriqué par empilement, dans cet ordre, d'un matériau de base, d'un matériau d'insert comprenant un métal ayant un point de fusion inférieur à celui du matériau de base, et d'une poudre métallique ou d'un corps fritté métallique ; et une couche de diffusion de pénétration est formée en chauffant le corps empilé pour faire fondre le matériau d'insert, et en amenant le matériau d'insert à pénétrer dans le corps fritté constitué de la poudre métallique, ou dans les pores du corps fritté.
PCT/JP2018/016463 2017-04-25 2018-04-23 Piston de moteur à combustion interne et procédé de fabrication de piston de moteur à combustion interne WO2018199024A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2017085778A JP2020109257A (ja) 2017-04-25 2017-04-25 内燃機関用ピストンおよび内燃機関用ピストンの製造方法
JP2017-085778 2017-04-25

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WO2018199024A1 true WO2018199024A1 (fr) 2018-11-01

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WO (1) WO2018199024A1 (fr)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04220195A (ja) * 1990-12-14 1992-08-11 Komatsu Ltd 接合用インサート材料
JPH09268304A (ja) * 1996-03-29 1997-10-14 Kawasaki Heavy Ind Ltd 傾斜組成型断熱層を有する金属製部材及びその製造方法
JP2010070792A (ja) * 2008-09-17 2010-04-02 Toyota Central R&D Labs Inc 薄膜の形成方法及び内燃機関の製造方法
WO2013081150A1 (fr) * 2011-12-02 2013-06-06 日本碍子株式会社 Structure de chambre de combustion de moteur et structure de paroi interne de trajet d'écoulement

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04220195A (ja) * 1990-12-14 1992-08-11 Komatsu Ltd 接合用インサート材料
JPH09268304A (ja) * 1996-03-29 1997-10-14 Kawasaki Heavy Ind Ltd 傾斜組成型断熱層を有する金属製部材及びその製造方法
JP2010070792A (ja) * 2008-09-17 2010-04-02 Toyota Central R&D Labs Inc 薄膜の形成方法及び内燃機関の製造方法
WO2013081150A1 (fr) * 2011-12-02 2013-06-06 日本碍子株式会社 Structure de chambre de combustion de moteur et structure de paroi interne de trajet d'écoulement

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