Cooling Channel Having Dam And Funnel

Abstract

A piston for an internal combustion engine includes a piston upper part and a piston lower part having a cooling channel including at least one inlet opening. A dam-type elevation is formed in the region of the at least one inlet opening through forging of the dam elevation in the cooling channel portion in the piston lower part. In one example, a funnel-shaped inlet contour is formed in the inlet opening by pre-forging. In one example, a V-shaped element is formed in the piston upper part cooling chamber portion in alignment with the inlet opening and used as a coolant jet splitter.

Claims

1. A piston of an internal combustion engine, consisting of an upper part and a lower part which are joined together, wherein there is provided a cooling channel which has at least one of an intake opening or a discharge opening for a coolant, characterized in that both a dam-like elevation is formed in the cooling channel in a region of the at least one intake opening or the discharge opening by a finish forged contour of a lower cooling channel region, and, on the inside of the piston, an inlet contour of the at least one intake opening or discharge opening is formed by pre-forging.

2. The piston of claim 1, wherein the at least one intake opening or a discharge opening comprise an intake opening and a discharge opening, wherein the pre-forging inlet contour is positioned at the intake opening and is funnel-shaped.

3. The piston of claim 2, further comprising a pre-forging at the discharge opening, wherein the pre-forging at the discharge opening is cylindrically-shaped.

4. The piston of claim 1, wherein the dam-like elevation is formed during forging of the piston lower part and extends over a width of the cooling channel.

5. The piston of claim 4, wherein the dam-like elevation comprises a height from 20% to 80% of a total height of the cooling channel.

6. The piston of claim 1, wherein the dam-like elevation is oriented transversely to the cooling channel and defines at least one recess at a transition between the dam-like elevation and a wall of the cooling channel.

7. The piston of claim 1, wherein the piston upper p-art defines a portion of the cooling channel and the piston lower part defines the intake opening, the piston upper part further comprising a V-shaped element integrally formed in the piston upper part by forging and extending into the cooling channel, the V-shaped element radially and angularly aligned with the intake opening.

8. The piston of claim 5 wherein the dam-like elevation height comprises 30% to 70% of the total height of the cooling channel

9. The piston of claim 6 wherein the at least one recess comprises a plurality of recesses at the transition between the dam-like elevation and the wall of the cooling channel

10. An internal combustion piston comprising: A piston upper part defining a portion of a cooling chamber having a width oriented radially relative to a piston stroke axis; a piston lower part connected to the upper part and forming a portion of the cooling chamber, the lower part defining a coolant intake opening and a discharge opening in communication with the cooling chamber; and a dam elevation positioned in the piston lower part cooling chamber portion and extending across the cooling chamber width, the dam positioned in a region adjacent to the intake opening, the dam elevation formed through forging at the time of forming the piston lower part.

11. The piston of claim 10 wherein the dam elevation comprises a first dam and a second dam elevation, the first and the second dam elevation positioned on opposing sides of the intake opening and operable to maintain a predetermined level of coolant in the cooling chamber when movement of the piston is stopped.

12. The piston of claim 11 wherein the piston lower part further comprises a pre-forging funnel-shaped inlet contour leading into the intake opening to aid the flow of coolant through the intake opening into the coolant chamber.

13. The piston of claim 11 wherein the piston lower part further comprises a discharge opening in communication with the coolant chamber, wherein the dam elevation comprises a third dam elevation and a forth dam elevation, the thrid and the fourth dam elevation positioned on opposing sides of the discharge opening and operable to maintain a predetermined level of coolant in the cooling chamber when movement of the piston is stopped.

14. The piston of claim 13 wherein the piston lower part further comprises a pre-forging cylindrical shape contour in communication with the discharge opening.

15. The piston of claim 12 wherein the piston upper part further comprises a V-shaped element positioned in the piston upper part coolant chamber portion and extending into the coolant chamber portion, the V-shaped element positioned in radial and angular alignment with the intake opening and operable to split a flow of coolant received through the intake opening toward alternate portions of the coolant chamber, the V-shaped element formed by forging at the time of forming the piston upper part.

16. The piston of claim 10 wherein the piston upper part further comprises a V-shaped element positioned in the piston upper part coolant chamber portion and extending into the coolant chamber portion, the V-shaped element positioned in radial and angular alignment with the intake opening and operable to split a flow of coolant received through the intake opening toward alternate portions of the coolant chamber, the V-shaped element formed by forging at the time of forming the piston upper part.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] An exemplary embodiment of a piston according to the invention is shown in different views in the figures and described in greater detail hereinbelow.

[0019] FIG. 1 is a cross-sectional view of an example of a piston of the present invention.

[0020] FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1.

[0021] FIG. 3 is a cut-way perspective view of one example of the piston.

[0022] FIG. 4 is a plan view of an example of a piston bottom part top surface

[0023] FIG. 5 is a bottom perspective view of an example of a piston upper part.

[0024] FIG. 6 is a bottom view of an example of a piston.

DETAILED DESCRIPTION

[0025] FIG. 1 shows, in section, a piston 1 which consists of a lower part 3 and an upper part 2. The two parts 2, 3 are produced separately from one another and joined together in a suitable manner

[0026] The piston 1 has, in a manner known per se, an outer circumferential annular zone 4 and can contain, but does not have to contain, a combustion bowl.

[0027] The lower part 3 forms a piston shaft 5 and a pin bore 6.

[0028] Further elements of a functioning piston 1 are present but are not described in detail or provided with reference numerals.

[0029] The two parts 2, 3 are connected together permanently and unreleasably by means of a suitable joining operation in order to form a one-piece piston 1 that is ready for use. The joining operation takes place in at least one joining plane 7. In the exemplary embodiment, the joining operation is a friction welding process.

[0030] The piston 1 further has a cooling channel 8. In this exemplary embodiment, the cooling channel 8 is formed by part-recesses both in the upper part 2 and in the lower part 3. This has the advantage that, before the two parts 2, 3 are joined together, their part-recesses are accessible and these part-recesses can therefore be optimally produced or finish machined, since they are no longer accessible after the two parts 2, 3 have been joined together.

[0031] Likewise in a manner known per se, the piston 1 has at least one intake opening 9 into which a free oil jet, which is delivered by an injection nozzle, is injected in the direction towards the cooling channel 8. If this intake opening 9 is the only opening, it can also serve as a discharge opening for the cooling oil which circulates in the cooling channel 8. Alternatively, at least one further discharge opening, in particular exactly one discharge opening, is present in addition to the at least one or exactly one intake opening 9 (the discharge opening will be described later).

[0032] According to the invention, starting from the lower base of the cooling channel 8, a dam-like elevation 10 is present next to the discharge opening 13. This dam-like elevation 10 is formed when the lower part 3 is produced. The lower part 3 can accordingly be produced in a casting process, for example, and the dam-like elevation can be formed during that process. Alternatively, the lower part 3 can be produced in a casting process and then the dam-like elevation 10 can be formed by a forming process (such as, for example, a forging process). Particularly preferably, both the lower part 3 with its geometries and the dam-like elevation 10 are produced in a forming process (such as, for example, a forging process).

[0033] When the lower part 3 is produced, this lower part acquires an inside geometry 11 with an in particular funnel-like inlet contour 12 of the intake opening 9. The inlet contour 12 can also have a shape other than a funnel shape. It is important to form the inlet contour 12 preferably in a forging process and thereby give it a shape with which the oil jet injected into the intake opening 9 is guided in a targeted manner in the direction towards the cooling channel 8. It is also important that the dam-like elevation 10 next to the intake opening 9 does not impede the entry of the injected oil jet, so that the injected oil is guided into the cooling channel 8 round the entire circumference.

[0034] FIG. 2 shows a plan view of the top side of the lower part 3, which points in the direction towards the upper part 2. It will be seen here that, in addition to an intake opening 9, a discharge opening 13 is also present. In this exemplary embodiment, exactly one intake opening 9 and exactly one discharge opening 13 are present, extending from which an encircling cooling channel 8 is present. It is, however, also conceivable that the cooling channel 8 is formed not around the entire circumference but is divided into, for example, at least two part-segments. In this case, each part-segment, for example, has its own intake opening and its own discharge opening.

[0035] As is apparent from the representation in FIG. 2, on each side, in the direction of the cooling channel 8, next to the intake opening 9 and the discharge opening 13, a dam-like elevation 10 is present on the lower part 3 and formed in one piece therewith. It is, however, also conceivable to provide only one dam-like elevation 10 or even no dam-like elevation 10 at all at one of the openings 9, 13, in particular in the region of the discharge opening 13.

[0036] It is further apparent from FIG. 2 that the lower part 3 has an outer circumferential joining face 14 and an inner circumferential joining face 15, which are formed by corresponding web portions of the lower part 3. These joining faces 14, 15 point towards corresponding joining faces of the upper part 2, which likewise forms web portions, at the end of which the joining faces are formed. By means of these corresponding joining faces pointing towards one another, the two parts 2, 3 are joined together permanently and unreleasably preferably by means of a friction welding process. Other geometric forms of the two parts 2, 3 and other joining processes which ensure that the two parts 2, 3 are joined together permanently and unreleasably are likewise conceivable.

[0037] FIG. 3 shows the piston 1 in a cutaway, three-dimensional view, in which the two parts 2, 3 have been joined together permanently and unreleasably. Furthermore, the position both of the intake opening 9 with at least one associated dam-like elevation 10 and the position of the discharge opening 13 (in this case also with an associated dam-like elevation 10) can be seen.

[0038] FIG. 4 shows, analogously to the representation in FIG. 2 in a three-dimensional view, a plan view of the lower part 3, wherein, as can also be seen in FIG. 2, a part-region of the cooling channel 8 is formed by the lower part 3.

[0039] FIG. 5 shows in a three-dimensional view the bottom side of the upper part 2, which points in the direction towards the lower part 3. In addition to the corresponding joining faces 14, 15, it can be seen that, in the part-region of the cooling channel 8 of the upper part 2, a dam-like elevation 10 (for example in the region of the intake opening 9) is likewise formed by the upper part 2. In this case, the at least one dam-like elevation 10 is not arranged next to the opening but is situated in the continuation of the cross section of the opening (intake opening 9 and/or discharge opening 13), so that the dam-like elevation 10 in the part-region of the cooling channel 8 of the upper part 2 serves as a jet splitter. By means of this jet splitter, the oil jet injected in particular through the at least one intake opening 9 is divided and can be divided in equal or different amounts in both directions of the cooling channel 8.

[0040] In FIG. 5 it is additionally also shown that the dam-like elevation 10 produced transversely to the cooling channel 8 has at least one recess 16, preferably a plurality of recesses, at the transition between the elevation 10 and the wall of the cooling channel 8, in particular in the apex region of the cooling channel 8. This makes it possible that a portion of the cooling oil which circulates in the cooling channel 8 is always able to circulate therein without being impeded by the dam-like elevation 10.

[0041] Finally, FIG. 6 shows the inside geometry 11 of the piston 1, in which the above-described parts 2, 3 have been joined together. In this case, it can be seen that a dam-like elevation 10 serving as a jet splitter is provided in the region of the intake opening 9 on the upper part 2 when viewed pointing downwards in the region of the cross section of the intake opening 9. Not visible but present are at least one dam-like elevation 10 in the part-region of the lower part 3 next to the intake opening 9 (and optionally also next to the discharge opening 13).

[0042] The orientation of the shown dam like elevation 10 either in the lower part 3 and/or the upper part 2 is by way of example and extends preferably radially starting from the piston stroke axis. Other radial orientations differing therefrom are of course also conceivable.

LIST OF REFERENCE NUMERALS

[0043] 1. Piston

[0044] 2. Upper part

[0045] 3. Lower part

[0046] 4. Annular zone

[0047] 5. Piston shaft

[0048] 6. Pin bore

[0049] 7. Joining plane

[0050] 8. Cooling channel

[0051] 9. Intake opening

[0052] 10. Dam-like elevation

[0053] 11. Inside geometry (inside)

[0054] 12. Inlet contour

[0055] 13. Discharge opening

[0056] 14. Outer joining face

[0057] 15. Inner joining face

[0058] 16. Recess