Cooling of a Piston by Means of Sodium-Filled Tubes

Abstract

Disclosed is an internal combustion engine piston wherein at least one space is formed into which a coolant is installed. In one example, the coolant is first introduced into a coolant container and the coolant container is thereafter inserted into the at least one space in the piston. In one example, the coolant is an alkali metal consisting of sodium.

Claims

1. (canceled)

2. The piston of claim 11, further comprising a closure element positioned over an opening defined by the space, the closure means operable to close the space opening after the insertion of the coolant container in the space.

3. The piston of claim 11, wherein after insertion into the space, the coolant container is fixed in its position in the space.

4. The piston claim 11, wherein the coolant container further comprises an elongate and cylindrical body.

5. The piston of claim 11, wherein the coolant container is cast into the piston.

6. A method for the production of a piston of a combustion engine, having an upper part with a ring zone and a piston skirt adjoining the upper part, wherein at least one space is formed in the piston, into which at least one space a coolant is introduced, the method comprising: installing the coolant into a coolant container; and installing the coolant container into the at least one space in the piston.

7. The method of claim 6 further comprising: closing the at least one space with a closure means after the installation of the coolant container into the at least one space in the piston.

8. The method of claim 6 further comprising: fixedly engaging the coolant container inside the at least one space in the piston.

9. The method of claim 6 wherein the coolant container is of elongate and cylindrical design.

10. The method of claim 6 further comprising: casting the coolant container into the piston.

11. A combustion engine piston comprising: an upper part having a ring zone; a piston skirt connected to the upper part; a space defined by the piston; and a coolant container operable to first receive and house a coolant, the coolant container and received coolant positioned in the space.

12. The piston of claim 2 wherein the coolant container further comprises an elongate and cylindrical body.

13. The piston of claim 12 wherein the space and the opening comprises a plurality of spaces each defining an opening, wherein the plurality of spaces openings are positioned in and in communication with a piston central region.

14. The piston of claim 12 wherein the space and the opening comprises a plurality of spaces each defining an opening, wherein the plurality of spaces openings are positioned at a piston outer region.

15. The piston of claim 12 wherein the coolant comprises an alkali metal.

16. A method for producing a combustion engine piston having an upper part including a ring zone, a piston skirt connected to the upper part, the method comprising: forming a plurality of cooling spaces in the piston, each of the plurality of cooling spaces defining an opening; installing a coolant in a plurality of coolant containers, the plurality of coolant containers separate and independent of the plurality of cooling spaces; sealingly closing the plurality of coolant containers preventing the coolant from exiting the plurality of coolant containers; installing the plurality of coolant containers including the coolant in respective of the plurality of cooling spaces; and preventing the coolant containers from exiting the cooling spaces.

17. The method of claim 16 wherein the forming of the plurality of cooling spaces and respective opening further comprises: forming the opening for each of the plurality of cooling spaces in a central region of the piston.

18. The method of claim 16 wherein the forming of the plurality of cooling spaces and respective opening further comprises: forming the opening for each of the plurality of cooling spaces in an outer region of the piston.

19. The method of claim 16 wherein installing the cooling containers in the respective of plurality of cooling spaces comprises casting the plurality of cooling containers in the piston.

20. The method of claim 16 wherein preventing the coolant containers from exiting the cooling spaces comprises: installing a closure element over the plurality of cooling spaces respective opening.

21. The method of claim 16 wherein preventing the coolant containers from exiting the cooling spaces comprises: fixedly securing the plurality of coolant containers in a respective of the plurality of coolant spaces.

Description

DETAILED DESCRIPTION

[0013] Reference numeral 1 indicates, by way of example, a one-piece piston 1, which has an upper part 2. A piston skirt 3 adjoins the upper part 2, wherein, in this design of the piston, the two opposite sections of the piston skirt 3 are connected by connecting walls 4, in which a pin bore 5 is also arranged. The pin bores 5 to receive the ends of a piston pin can be present but do not have to be present. The ends of the piston pin can also be arranged in some other way on the lower side of the upper part 2. In a manner known per se, the upper part 2 has a ring zone 6, wherein a central region (FIG. 1) is denoted by 7 in the inner region of the piston 1.

[0014] A combustion chamber recess 8 can be present in the upper part 2 of the piston 1, as can a cooling passage 9 running around in the form of a ring. The combustion chamber recess 8 and/or the cooling passage 9 can, but need not be, present, depending on the intended use of the piston 1.

[0015] A closure for openings 11 of spaces 12 situated within the piston 1 is indicated by 10 in FIG. 1.

[0016] Considering FIG. 2, it becomes clear that, in principle, the at least one space 12, in this case a plurality of spaces 12, is arranged in the piston 1, i.e. within the solid material thereof. While, in FIG. 1, it is assumed that the openings 11 of the spaces 12 are accessible from the central region 7 (inner region of the piston 1), FIG. 2 illustrates that the openings 11 of the spaces 12 are accessible from the outer region of the piston 1 (e.g. from the connecting wall 4 or the piston skirt 3).

[0017] Irrespective of the direction from where the spaces 12 are accessible and where the openings 11 (insertion openings) thereof are located, the spaces 12 are thus introduced in the required numbers into the main body (solid material) of the piston after the production of the piston 1 (to be more precise of a piston blank) or during production itself. As already described, introduction can be accomplished by means of lost cores which are flushed out. Instead, the respective space 12 can be introduced by suitable methods, e.g. drilling, milling or the like, after the production of the piston blank. This can be seen, for example, from the piston shown in FIG. 2, where the spaces 12 are arranged obliquely in the piston 1 and are aligned in the direction of the central region 7.

[0018] After a piston as shown in FIG. 2 has been prepared, coolant containers 13 that have previously been produced and filled with coolant are inserted into the spaces 12 provided for them, as illustrated in FIG. 3. After insertion, the associated openings 11 of the space 12 are closed, or the respective coolant container 13 is inserted into the space 12 in such a way that it is fixed permanently in its position there after the completion of the insertion process. It is absolutely imperative that this fixing in position should be performed in such a way that the coolant container 13 cannot move out of the space 12 during the upward and downward movement of the piston 1 in the cylinder of the combustion engine.

[0019] As can be seen in FIGS. 2 and 3, the spaces 12 and accordingly also the coolant containers 13 are of elongate and cylindrical configuration. This elongate and cylindrical configuration enables the coolant container 13 to be produced in a simple manner by using tubular material, which is closed at one end, for example, and then filled with the coolant, after which, in turn, the other end is closed gas tightly. Moreover, this elongate configuration has the advantage that the strength of the piston 1 is weakened only slightly, if at all, when the spaces 12 are introduced. It can be regarded as a further advantage that, by virtue of the elongate extent of the coolant container 12, very good heat transfer can take place from the regions which are highly stressed in terms of temperature (in the illustrative example the internally situated dome of the combustion chamber recess 8, for example) in the direction of regions which are less highly stressed in terms of temperature.

[0020] To fill the coolant container 12 and for heat transfer, any suitable coolant may be considered. Alkali metals, e.g. sodium, are of particular advantage since they have very good heat transfer in the temperature working range of the piston 1.

LIST OF REFERENCE SIGNS

[0021] 1. piston [0022] 2. upper part [0023] 3. piston skirt [0024] 4. connecting wall [0025] 5. pin bore [0026] 6. ring zone [0027] 7. central region [0028] 8. combustion chamber recess [0029] 9. cooling passage [0030] 10. closure [0031] 11. openings [0032] 12. space [0033] 13. coolant container