DE102009027148A1 - Piston i.e. aluminum piston, for diesel engine, has cooling channel system comprising inlets and outlets for cooling medium, where inlets are provided at one cooling channel and outlets are provided at other cooling channel - Google Patents

Abstract

The piston (10) has a cooling channel system comprising circular outer and inner cooling channels (18, 20) and a connection channel connecting the cooling channels. The channel system comprises inlets and outlets for a cooling medium. The inlets are provided at one of the cooling channels, and the outlets are provided at the other cooling channel. The cooling channels are partially provided in an axial piston direction at different levels. The channels exhibit different circumferential lengths. The inner cooling channel is provided in an area of a combustion chamber base.

Description

TECHNICAL AREA

The The invention relates to a piston for an internal combustion engine, with a cooling channel system of at least two annular Cooling channels.

STATE OF THE ART

With increasing performance requirements for pistons, especially for diesel engines, the thermal and mechanical loads continue to increase. There are currently various approaches to Increasing the load capacity of the piston tracked. For example an increase in the hot strength of the piston alloy was provided. Of the However, use of aluminum alloys in particular is thermal limited since the elements added to increase the hot strength, especially nickel and copper, to lower the melting temperature to lead. Further measures to increase the heat resistance of aluminum pistons consist in the introduction of reinforcements, for example by remelting, alloying, Introduction of metallic or ceramic fibers or of dispersion materials. Furthermore, there is basically the possibility Producing pistons from composite materials. The previously known Solutions have the disadvantage of high production costs.

Another way to describe the DE 10 2006 027 354 A1 and DE 10 2004 056 769 A1 , which improve the load capacity of the piston by an improved cooling architecture. The present invention represents a further development of the cooling architecture of DE 10 2004 056 769 A1 which forms the preamble of the main claim. Therein, a plurality of cooling channels or interconnected cooling sections are provided which extend in different zones of the piston.

PRESENTATION OF THE INVENTION

Of the Invention is the task. based, a piston with improved To create cooling effect.

The Solution of the problem is achieved by the one described in claim 1 Piston.

After that the piston has a cooling channel system of at least two annular cooling channels. The two annular cooling channels are with at least connected to a connecting channel, wherein the cooling channel system one or more tributaries and one or more outflows for coolant. The inventive Piston is characterized by the fact that all inflows one of the annular cooling channels and all drains at another of the annular ones Cooling channels are provided. By the Zu- and Drains are systematically separated in this way is Ensures that coolant, through the Inflows is introduced, a considerable Part of the cooling duct system travels before it is discharged through the drains. Thereby can the temperatures in the entire piston are lowered more effectively.

Preferably There are at least two of the annular cooling channels in the axial piston direction at least partially on different Level to a more spacious and more targeted cooling especially claimed areas. To the arrangement "on different levels "is to say that including a superimposing and / or Side by side arrangement of self-contained cooling channels or cooling duct sections is meant. It is preferable provided that cooling channels or cooling channel sections, extending along the piston axis on different (axial) Level, in the area of the shortest connection between two such channels and sections by piston material are delimited from each other. Nevertheless, they could go through a suitable, in the broadest sense helical connection be fluidly interconnected. Besides can the connection between two such cooling channel sections also by largely parallel to the piston axis extending connection openings or drilling done. This is especially true when the two cooling duct sections only in the direction of Piston axis, but not in the radial direction, on different Level.

Preferably have at least two of the annular cooling channels different circumferential lengths to a more spacious and more targeted cooling of particularly stressed areas to enable.

One good compromise of constructive effort and space cooling of the piston results when the piston exactly two annular cooling channels having.

Preferably, the radially inner cooling channel is in a piston with two cooling rings in the region of the combustion chamber base of the piston, whereas the radially outer cooling channel is provided in the region of the combustion chamber edge. It has been found that a particularly good cooling effect can be achieved in an embodiment in which, in the case of a piston with a combustion chamber recess, at least one cooling channel is provided in the area radially adjacent to the combustion chamber recess. In other words, this is a cooling channel in a respect to the piston axis "upper" in the order area of the piston crown. In addition, it has proved to be advantageous to provide at least one cooling channel in a region axially below the combustion chamber trough. This cooling channel can be arranged, for example, in the region above an outer edge of the combustion bowl.

Possibly In addition, it has proved to be advantageous at least one cooling channel in a region axially below to provide the combustion bowl. This cooling channel can, for example in the area below an outer edge of the Be arranged combustion chamber trough. Preferably, there is one radially inner cooling channel in the area of the bolt holes.

Preferably has the radially outer cooling channel a larger cross section. This way will the flow behavior of the coolant in the cooling channel system controlled advantageously.

Preferably is the at least one inflow at the radially outer Cooling channel and the at least one outlet at the radial inner cooling channel. In this way, the cooling takes place from a radial view from outside to inside. Furthermore, such is Arrangement advantageous for the design of inflows and outflows of the coolant.

Preferably are exactly two tributaries on the radially outer Cooling channel and exactly two outflows at the radial inner cooling channel provided, each arranged symmetrically can be to the coolant flow in the cooling channel system to optimize.

Preferably are between the cooling channels more connection channels provided, preferably four to eight, to the coolant flow to improve in the cooling duct system.

Preferably the several connection channels are arranged symmetrically, so as not to affect the running properties of the piston.

To the annular cooling channels are preferably circular symmetrical about the piston axis provided and each circular cooling channel preferably forms in this case a plane that is perpendicular to the piston axis.

Preferably has at least one of the annular cooling channels along the circumference at least a region of a different cross section on to the flow characteristics and local cooling effect to control.

It It has turned out that for the purpose local areas of a larger cross-section are advantageous.

Preferably at least one drain is located above the bolt so that the escaping coolant is on the bolt in the area the bolt hole and the connecting rod can reach to an effective To ensure cooling of these particularly stressed areas.

For this and for reasons of symmetry are preferably two outflows provided, which are diametrically opposed and so are arranged that the escaping coolant on the Bolt, get into the area of the bolt holes and on the connecting rod can.

The Invention is particularly for pistons made of aluminum or a Aluminum alloy suitable.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a three-dimensional, cutaway view of a piston;

2 shows the piston 1 in a different perspective and in a closed loop presentation;

3 shows the channel system in a three-dimensional representation, wherein the area of the piston head has been omitted for better visualization of the channel system;

4 shows the piston from below;

5 is a three-dimensional representation of the cooling channel system;

6 shows the cooling duct system from the side.

WAYS TO EXECUTE THE INVENTION

As in 1 can be seen, the piston points 10 , which is preferably made of aluminum or an aluminum alloy, a combustion bowl 12 , which may be ω-shaped, several annular grooves 14 and two bolt holes 16 on. The embodiment shown has in the piston head 11 two - except for in this figure, not shown compounds - closed annular cooling channels 18 and 20 on, in the truncated version of the 1 only the openings can be seen.

In 2 are the annular channels 18 and 20 shown in three dimensions in connection with the piston. The cooling channels have a substantially circular cross-section. A first cooling channel 18 is located in an area "next to" the combustion chamber trough 12 and in the axial direction on comparison high level, in particular a short distance below the piston crown 22 , In that regard, he will below as a floor cooling channel 18 designated.

A second cooling channel 20 is at a level below the combustion bowl 12 and below the floor cooling channel 18 intended. This cooling channel is subsequently referred to as a hollow cooling channel 20 designated. It is not only, as mentioned, with respect to the height in the direction of the piston axis at a lower level, but is also formed at a radially inner position. At this point, the trough cooling channel 20 particularly efficient for cooling the hot zone between the combustion bowl 12 and the bolt holes 16 to care.

In the 2 to 6 the focus is on the cooling duct system. In the 3 to 6 are the coolant inlets 28 and the coolant flows 30 to recognize. The inflow of cooling and / or lubricating fluid via the separate and diametrically arranged feeds 28 that with the floor cooling channel 18 are connected. The feeds 28 each have an opening that opens into the area that is surrounded by the piston skirt. Nozzles, not shown in the drawings, may produce a jet of coolant that enters the respective inlet ports of the inlets 28 entry. In this way, the cooling channels can be supplied with coolant.

Two diametrically opposed processes 30 are with the well cooling channel 20 connected. The processes are designed so that they can deliver the coolant to the connecting rod. Both cooling channels are with four connecting channels 26 connected to allow a cooling circuit through the two annular cooling channels and to ensure a connection between the inlets and the processes.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102006027354 A1 [0003]
• - DE 102004056769 A1 [0003, 0003]

Claims (16)

Piston for an internal combustion engine, with a cooling channel system comprising at least two annular cooling channels ( 18 . 20 ) and at least one of the two annular cooling channels ( 18 . 20 ) connecting channel ( 26 ), wherein the cooling channel system one or more inflows ( 28 ) and one or more outflows ( 30 ) for a coolant, characterized in that all inflows ( 28 ) on one of the annular cooling channels ( 18 . 20 ) and all outflows ( 30 ) at another of the annular cooling channels ( 18 . 20 ) are provided. Piston according to claim 1, characterized in that at least two of the annular cooling channels ( 18 . 20 ) are in the axial piston direction at least partially at different levels. Piston according to one of claims 1 to 3, characterized in that at least two of the annular cooling channels ( 18 . 20 ) have different circumferential lengths. Piston according to claim 3, characterized in that the piston exactly two annular cooling channels ( 18 . 20 ) having. Piston according to claim 4, characterized in that the piston has a piston head ( 22 ) with a combustion bowl ( 12 ), which has a combustion chamber base and a combustion chamber edge, wherein the radially inner cooling channel ( 20 ) is provided in the region of the combustion chamber base, whereas the radially outer cooling channel ( 18 ) is provided in the region of the combustion chamber edge. Piston according to claim 4 or 5, characterized in that the piston pin bores ( 16 ), and the radially inner cooling channel ( 20 ) in the area of the bolt holes ( 16 ) is located. Piston according to one of claims 4 to 6, characterized in that the radially outer cooling channel ( 18 ) has a larger cross section than the radially inner cooling channel ( 20 ) having. Piston according to one of claims 4 to 7, characterized in that the at least one inflow ( 28 ) on the radially outer cooling channel ( 18 ) and the at least one outflow ( 30 ) on the radially inner cooling channel ( 20 ) is provided. Piston according to claim 4 to 8, characterized in that exactly two tributaries ( 28 ) on the radially outer cooling channel ( 18 ) and exactly two outflows ( 30 ) on the radially inner cooling channel ( 20 ) are provided. Piston according to one of the preceding claims, characterized in that between the annular cooling channels ( 18 . 20 ) several connection channels ( 26 ) are provided, preferably four to eight, which the two annular cooling channels ( 18 . 20 ) connect with each other. Piston according to claim 10, characterized in that the plurality of connecting channels ( 26 ) are arranged symmetrically to each other. Piston according to one of the preceding claims, characterized in that the annular cooling channels ( 26 ) are provided circularly symmetrical about the piston axis, and each circular cooling channel ( 18 . 20 ) forms a plane which is perpendicular to the piston axis. Piston according to one of the preceding claims, characterized in that at least one of the annular cooling channels ( 18 . 20 ) has at least one region of a deviating cross section along the circumference, preferably local regions of a larger cross section are provided. Piston according to one of the preceding claims, characterized in that the piston has a bolt which is inserted into pin bores ( 16 ) of the piston is mounted with connecting rods, and at least one outflow ( 30 ) is arranged above the bolt, that the exiting coolant on the bolt, preferably in the region of the bolt holes ( 16 ) and on the connecting rod, can get. Piston according to claim 14, characterized in that exactly two outlets ( 30 ) are provided, which are diametrically opposed and are arranged so that the escaping coolant can reach the bolt, preferably in the region of the bolt holes and on the connecting rod. Piston according to one of the preceding claims, characterized in that the piston is an aluminum piston or is an aluminum alloy piston.