PISTION WITHOUT A CLOSED COOLING CHAMBER FOR INTERNAL COMBUSTION ENGINES WITH AT LEAST ONE COOLING OIL NOZZLE PER CYLINDER AND METHOD FOR COOLING SAID PISTON

Abstract

An internal combustion engine piston having a cooling chamber open to in a direction toward of pin boss bores. In one example, a shaft separates an inner form of a cooling chamber and a cooling pocket. A transfer hole allows passage of a cooling oil between the inner form and the cooling pocket or several cooling pockets. In one example when the piston is at a bottom dead center position, a cooling oil nozzle is directed toward the transfer hole and when the piston is at a top dead center position, the cooling oil nozzle is directed to a hub region of the cooling chamber.

Claims

1. A piston (1, 100) for internal combustion engines having an annular field (3), a shaft (4), pin hub holes (5) and a cooling chamber (8), characterized in that the cooling chamber (8) is constructed to be open in the direction of the pin hub holes (5).

2. The piston (1, 100) as claimed in claim 1, characterized in that the cooling chamber (8) comprises an inner form (6) and at least one cooling pocket (7).

3. The piston (1, 100) as claimed in claim 1, characterized in that at least one transfer hole (9) is provided for the passage of cooling medium through a wall of the shaft (4).

4. The piston (1, 100) as claimed in claim 3, characterized in that the at least one transfer hole (9) provides a connection between at least one: cooling pocket (7) and the inner form (6); or at least one cooling pocket (7) and at least one additional cooling pocket (7).

5. The piston (1, 100) as claimed in claim 3, characterized in that at least one cooling oil nozzle (10) is directed toward the transfer hole (9) or a hub region (12).

6. The piston (1, 100) as claimed in claim 5, characterized in that the at least one cooling oil nozzle (10) is directed at a bottom dead center (BDC) of the piston (1, 100) toward the at least one transfer hole (9).

7. The piston (1, 100) as claimed in claim 5, characterized in that the at least one cooling oil nozzle (10) is directed at the top dead center (TDC) of the piston (1, 100) toward the hub region (12).

8. A method for cooling a piston (1, 100) with an open cooling chamber (8), characterized by the following steps: 8a) supplying cooling oil (11) via at least one cooling oil nozzle (10) to a lower side of the piston (1, 100); 8b) injecting the cooling oil (11) into at least one transfer hole (9) at a top dead center (TDC) of the piston (1, 100); 8c) injecting the cooling oil (11) into the region between the at least one transfer hole (9) at the top dead center of the piston (1, 100) and the at least one hub region (12) at a bottom dead center (BDC) of the piston (1, 100); 8d) injecting the cooling oil (11) into at least one cooling pocket (7) in the hub region (12) of the piston (1, 100); and 8e) repeating the steps 8a) to 8d) during operation of an internal combustion engine.

9. The method as claimed in claim 8, characterized in that cooling oil (11) is directed into the inner form (6) and/or a cooling pocket (7) through the at least one transfer hole (9).

10. The method as claimed in claim 8, characterized in that cooling oil (11) can flow away freely from the entire cooling chamber (8) into the region below the piston (1, 100).

11. The piston (1, 100) as claimed in claim 2, characterized in that at least one transfer hole (9) is provided for the passage of cooling medium through a wall of the shaft (4).

12. The piston (1, 100) as claimed in claim 11, characterized in that at least one cooling oil nozzle (10) is directed toward the transfer hole (9) or a hub region (12).

13. The piston (1, 100) as claimed in claim 11, characterized in that the at least one transfer hole (9) provides a connection between at least one: cooling pocket (7) and the inner form (6); or at least one cooling pocket (7) and at least one additional cooling pocket (7).

14. The piston (1, 100) as claimed in claim 13, characterized in that at least one cooling oil nozzle (10) is directed toward the transfer hole (9) or a hub region (12).

15. The method as claimed in claim 8 characterized in that passage of the cooling oil (11) between an inner form (6) and the at least one cooling pocket (7) through the at least one transfer hole (9).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIGS. 1A and 1B are views of a single-piece piston according to the invention without a closed cooling chamber,

[0032] FIGS. 2A and 2B are further views of a single-piece piston according to the invention without a closed cooling chamber according to FIGS. 1A and 1B,

[0033] FIG. 3 shows a single-piece piston without a closed cooling chamber with an obliquely injecting cooling oil nozzle,

[0034] FIGS. 4A and 4B are two views of a single-piece piston without a closed cooling chamber with injecting cooling oil nozzles,

[0035] FIGS. 5A and 5B show another embodiment of a single-piece piston according to the invention without a closed cooling chamber,

[0036] FIG. 6 shows a single-piece piston according to FIGS. 5A and 5B without a closed cooling chamber with an obliquely injecting cooling oil nozzle, and

[0037] FIGS. 7A and 7B are two views of a single-piece piston according to FIGS. 5A and 5B without any closed cooling chamber with injecting cooling oil nozzles.

[0038] FIGS. 1A, 1B, 2A, 2B, 3, 4A and 4B show a first embodiment of a single-piece piston 1 according to the invention without a closed cooling chamber, that is to say, with a cooling chamber which is open toward the rear when viewing the Figures. A second embodiment of a single-piece piston 100 according to the invention without any closed cooling chamber is shown in FIGS. 5A, 5B, 6, 7A and 7B.

[0039] Elements which are the same are given the same reference numerals in all the Figures.

[0040] In the following description of the Figures, terms such as above, below, left, right, front, rear, et cetera, refer exclusively to the exemplary illustration selected in the respective Figures and position of the device and other elements. These terms are not intended to be understood to be limiting, that is to say, these references may change as a result of different positions and/or mirror-symmetrical configuration or the like.

[0041] FIGS. 1A, 1B, 2A, 2B, 3, 4A and 4B show a single-piece piston 1 which is produced, for example, from steel. This piston 1 is constructed with an open cooling channel. It has a cooling chamber 8 which is formed by the following regions or elements of the piston 1: [0042] cooling pockets 7 which are opposite an annular field 3 and which are constructed at the inner periphery of the piston 1, [0043] an inner form 6 which is opposite a combustion chamber bowl 2 in the direction of pin hub holes 5.

[0044] The cooling pockets 7 are divided by a shaft 4 into two regions. The outer region is referred to as a hub region 12. The inner region adjoins the inner form 6 in the direction of the annular field 3. So that a cooling medium, for example, a cooling oil 11, can pass through the shaft 4, transfer holes 9 are arranged between these regions. Via cooling oil nozzles 10, depending on the position of the piston 1 inside a cylinder which is not illustrated, cooling oil 11 is alternately injected into an inlet opening of the transfer holes 9 and into the hub region 12. FIG. 4A shows the piston 1 at the bottom dead center (BDC), that is to say, the location at which the downward movement of the piston changes into an upward movement, during the injection of the cooling oil 11 into the transfer holes 9 to the inner form 6. FIG. 4B shows the piston 1 at the top dead center (TDC), that is to say, the location at which the upward movement of the piston 1 changes into a downward movement, during the injection of the cooling oil 11 into the cooling pockets 7 in the hub region 12. During the downward movement of the piston 1, an increasingly large quantity of the cooling oil volume flow enters the transfer holes 9. Consequently, an increasing amount of cooling medium reaches the inner form 6 and the cooling pockets 7 which are associated therewith. During the upward movement of the piston 1, an increasing amount of the cooling oil volume flow reaches the hub region 12 and consequently the cooling pocket 7 which is provided at that location. In FIGS. 2A and 2B of the piston 1, the transfer holes 9 can clearly be seen. FIG. 3 shows the obliquely injecting cooling oil nozzle 10 particularly clearly.

[0045] FIGS. 5A, 5B, 6, 7A and 7B show a second embodiment of a single-piece piston 100 according to the invention. The deviating geometric construction of a shaft 4 can be clearly seen here. In the first embodiment in the piston 1, the shape is box-like when viewed from below. In the second embodiment, in a bottom view of the piston 100, the curved portions of the shaft 4 can be seen. FIGS. 5A and 5B show the arrangement of the transfer holes 9 on the piston 100. FIG. 6 shows the obliquely injecting cooling oil nozzles 10 on the piston 100. FIG. 7A shows the piston 100 at the bottom dead center (BDC) when the cooling oil 11 is injected into the transfer hole 9 to the inner form 6. FIG. 7B in turn shows the piston 100 at the top dead center (TDC) when the cooling oil 11 is injected into the cooling pockets 7 in the hub region 12.

[0046] The piston which is described above and which is also claimed in the patent claims (either generally or in accordance with the first or second embodiment) is used in a manner known per se in an internal combustion engine. The internal combustion engine has at least one cylinder chamber in which the piston is arranged and which can move up and down (oscillate) in a known manner. There is provided in a crank housing of the internal combustion engine the at least one oil injection nozzle (also referred to as a cooling oil nozzle) via which an oil jet is discharged in the direction of the piston base, that is to say, in the direction of the cooling chamber which is open in a downward direction in order to supply to the cooling chamber which is open in a downward direction the cooling medium which passes along and consequently over the wall of the cooling chamber which is open in a downward direction, receives heat at that location and is then returned to the inner region of the piston again and consequently also to the inner region of the crank housing in order to discharge the heat which is produced as a result of the combustion in the region of the piston base. Subsequently the cooling medium which has been returned in the crank housing is returned to the cooling circuit and can be discharged again through the injection nozzle as an oil jet.

LIST OF REFERENCE NUMERALS

[0047] 1 Piston [0048] 100 Piston [0049] 2 Combustion chamber bowl [0050] 3 Annular field [0051] 4 Shaft [0052] 5 Pin hub hole [0053] 6 Inner form [0054] 7 Cooling pocket [0055] 8 Cooling chamber [0056] 9 Transfer hole [0057] 10 Cooling oil nozzle [0058] 11 Cooling oil [0059] 12 Hub region