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 
  • F02F3/16—Pistons  having cooling means
  • F02F3/20—Pistons  having cooling means the means being a fluid flowing through or along piston
  • F02F3/22—Pistons  having cooling means the means being a fluid flowing through or along piston the fluid being liquid
• • 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 
  • F02F3/0015—Multi-part pistons
  • F02F3/003—Multi-part pistons the parts being connected by casting, brazing, welding or clamping
• • 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 
  • F02F3/0015—Multi-part pistons
  • F02F3/003—Multi-part pistons the parts being connected by casting, brazing, welding or clamping
  • F02F2003/0061—Multi-part pistons the parts being connected by casting, brazing, welding or clamping by welding

Definitions

• the invention relates to a piston for an internal combustion engine according to the preamble of patent claim 1.
• Utilizing the direct injection can be achieved particularly efficient combustion and thus a particularly efficient utilization of the chemical energy stored in the fuel. However, this results in higher ones
• a further piston for an internal combustion engine which is designed in two pieces.
• the piston is here in an upper part and a Divided lower part, which are connected in the region of a circumferential joint by means of orbital friction welding. This makes it possible to perform the piston regions of different materials, so as to find a compromise between thermal capacity and weight.
• DE 10 2008 01 1 922 A1 requires further parts in order to represent the desired annular cooling channel.
• an additional element is provided for this purpose, which must be connected to the two piston parts, so as to form the cooling channel.
• the resulting need for further joining operations also increases the production cost of the piston here.
• the present invention is therefore an object of the invention to provide a piston of the type mentioned, which is both thermally stable and weight-optimized as well as inexpensive to manufacture.
• Such a piston for an internal combustion engine has a piston upper part and a
• Piston lower part which are connected by welding cohesively along at least one joining surface. Furthermore, an annular extending in a piston skirt cooling channel is provided. According to the invention, the cooling channel is formed jointly by the upper piston part and the lower piston part. By this is to be understood in particular that no other components in the formation of the cooling channel have part. The cooling channel is thus formed only by the joining of upper piston part and lower piston part, since no additional elements are provided, are also more
• piston upper part and lower piston part are therefore particularly cost-effective in its manufacture.
• the separation in piston upper part and lower piston part also the desired weight and temperature resistance advantages can be achieved.
• the at least one joining surface extends through the cooling channel. This allows the cooling channel to be formed by
• the joining surface is not within the range of the maximum mechanical loads of the piston, so that particularly durable pistons are obtained.
• the at least one joining surface is a
• the at least one joining surface can alternatively be used as a cylinder jacket around the
• As a welding method for connecting the upper piston part and the lower piston part is particularly suitable for friction welding and laser welding. Especially when
• Laser welding results in particularly strong welds and a particularly high degree of flexibility in the arrangement of the joining surfaces, which need not lie on a common plane.
• the defined, low heat input results in a very low distortion of the welded components.
• non-rotationally symmetrical welding surfaces can be selected so that a particularly high degree of design freedom exists.
• Fig. 1 is a schematic sectional view through the connection region of a
• Piston shell and piston lower part for an embodiment of a piston according to the invention
• Fig. 2 is a schematic sectional view through the connection area
• FIG. 3 is a schematic sectional view through a piston upper part and a piston lower part for an alternative embodiment of a piston according to the invention
• Piston lower part for an embodiment of a piston according to the invention during the joining by laser welding
• Fig. 4 is a schematic sectional view of the cooling channel region of a
• Embodiment of a piston according to the invention with several possible joining planes Embodiment of a piston according to the invention with several possible joining planes.
• Motor vehicle is formed from a piston upper part 12 and a lower piston part 14.
• the upper piston part 12 comprises a piston head 16 and the combustion bowl 18 of the piston 10, while the lower piston part 14 substantially forms the piston skirt 20. Due to the two-part design as a piston upper part 12 and lower piston part 14, it is possible to use 10 different materials for thermally different loaded areas of the piston.
• the piston top 12 can be made of steel to the high combustion chamber temperatures in the
• piston base 14 Internal combustion engine of a motor vehicle to resist, while the piston base 14 can be made to save weight of aluminum or an aluminum-based alloy. Between piston upper part 12 and lower piston part 14, a cooling channel 22 is formed, which is shown schematically in the figures in the size that it has in the assembled state of upper piston part 12 and lower piston part 14.
• Piston upper part 12 and lower piston part 14 are connected via respective welding surfaces 24, 26 with each other.
• Beam welding process such as laser welding or
• Electron beam welding find use. Both methods are suitable for connecting different material combinations.
• the cooling channel 22 is thus formed only by the joining of upper piston part 12 and lower piston part 14 in its final form.
• FIG. 2 shows an alternative embodiment of the piston 10, in which a joining surface 30 lies on a cylinder jacket about the rotational symmetry axis 28.
• the cooling channel 22 is formed only by the joining of the piston upper part 12 and piston lower part 14. Due to the conical shape of the joint surface 30 piston upper part 12 and lower piston part 1 can be assembled without being radially against each other. In other words, the arrangement of piston upper part 12 and lower piston part 14 is self-centering. This is particularly advantageous when
• Piston upper part 12 and piston lower part 14 to be connected by friction welding, since no additional centering is necessary here.
• the joining surface 30 extends on a
• Piston upper part 12 and lower piston part 14 is here generated by a laser 32, which melts by means of a laser beam 34, the material of upper piston part 12 and lower piston part 14 in the region of the joining surface 30 and so creates a material connection.
• a laser 32 melts by means of a laser beam 34, the material of upper piston part 12 and lower piston part 14 in the region of the joining surface 30 and so creates a material connection.
• Such welds are of particularly high quality, since no bulging weld beads are formed, which could reduce the volume of the cooling channel 22.
• the joining surfaces 30, 32, 34, 36 can be arranged almost arbitrarily during laser welding.
• the joining surfaces 30, 32 are here again
• the joining surface 34 extends cylindrically about the axis of rotational symmetry, and the joining surface 36 is arranged such that the rotational symmetry axis forms a surface normal on the joining surface 36.
• the position of the joining surfaces 30, 32, 34, 36 can thus be chosen much more freely than during friction welding. Even completely non-symmetrical joining surfaces are possible, so that consideration can be given to other design features of the piston 10. Due to the low heat input during laser welding, there is also very little distortion in the welding area

Landscapes

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

Applications Claiming Priority (2)

Publications (1)

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ID=44735877

Family Applications (1)

Country Status (2)

Cited By (2)

Families Citing this family (1)

Citations (12)

• 2010
  • 2010-11-25 DE DE201010052578 patent/DE102010052578A1/de not_active Withdrawn
• 2011
  • 2011-09-24 WO PCT/EP2011/004792 patent/WO2012069103A1/de active Application Filing

Patent Citations (12)

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