JPS608324B2 - Structural parts with walls that receive heat loads in internal combustion engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a structural part, such as a silica head or a piston, which has walls subjected to heat loads in an internal combustion engine, and which has two cooling chambers separated by an intermediate wall.
The cooling liquid flows from the outer cooling chamber through a number of thin flow holes in the intermediate wall with pressure reduction into the inner cooling chamber and is directed towards the wall to be cooled, the inner cooling chamber having one outlet. Relates to types connected to pipes.

A structural part subjected to heat loads of this type is known from German Patent No. 511 545.

In this known example, the surface of the wall to be cooled that is opposite to the side that receives heat is linear. If such a wall is to receive a large mechanical load, it must be designed to have a sufficiently large thickness. This, however, is accompanied by an increase in thermal stresses within the wall. The object of the invention is to provide a heat-loaded structural part which can be manufactured easily and which, despite the high mechanical strength of the wall to be cooled, is accompanied by only small thermal stresses. be.

This object was achieved by the present invention as follows.

That is, the wall to be cooled has a number of cooling holes formed as cylindrical cavities, leaving webs, and the inflow of the cooling liquid is directed towards areas within these cavities near the webs. at least a part of the area near the web of the hollow chamber opens into an outflow passage formed in a direction transverse to the flow direction of the coolant and connected to the discharge pipe, the central axis of the hollow chamber being The inflow of the cooling liquid from the flow hole is directed toward one of the two cross-sectional divided portions that are symmetrical with respect to the plane, and the other cross-sectional divided portion is directed toward the outflow passage. It is connected to According to such a structure of the present invention, cooling can be performed at a position extremely close to the high-temperature surface without causing an undue decrease in mechanical strength.

The provision of cooling holes increases the surface area to be cooled and thus the heat dissipation. This is accompanied by a reduction in the temperature in the wall to be cooled t and thus in the thermal stresses.
The webs separating the cooling holes from each other reduce the wall thickness between the lower edge of the cooling hole and the hot side of the wall by 4.
・It is possible to design a structure. This is because the web can absorb mechanical loads. Cooling holes in the form of cylindrical hollow chambers facing approximately diametrically 2
A good flow of the coolant in the form of a turn occurs because the coolant flows into one of the green zones and out of the other green zone into the outflow channel.

The cylindrical hollow chamber can be easily formed using a drilling machine or the like. Advantageously, the bottom of each cooling hole is curved or conical in order to circulate the cooling liquid.

Such measures not only result in a better uniform flow of coolant in the cooling holes, but also increase the mechanical strength of the wall to be cooled. The invention will now be explained with reference to the embodiment shown in the drawings: The cylinder head of the internal combustion engine shown in FIGS. 3 and one cylinder cover housing 4 arranged thereon.

The cylinder cover wall 3 and the cylinder cover housing 4 are immovably connected via fastening bolts 5 located on the inside and fastening bolts (not shown) located on the outside. A number of chambers 6 are provided in the cylinder cover housing 4 and are connected to one another by radial lateral walls with closures 7. This chamber 6 further has one inlet 8 and a coolant supply conduit (not shown) is connected to this inlet 8. The wall 91 is provided with a large number of rib wings Q in the radial direction (see FIG. 2). A large number of communication holes 11 having a circular cross section pass through these ribs 10. The cylinder cover wall 3 is connected to the combustion chamber 1. It has a large number of cooling holes 2, 12a on the opposite side, and these cooling holes 12,
12a is designed such that the end or side surface of the wall of the cooling hole is located as close as possible to the cylinder cover wall 3. A web 13 is left between the cooling hole necks 2 of the cooling hole 12, i.e., whose longitudinal axis A-A is at an angle of 90 degrees to the surface receiving the heat of the cylinder cover shot 3. The webs 13 increase the mechanical strength of the cylinder cover wall 3 and make it possible to bring the bottoms 14 of the cooling hole holes 2 close to the combustion chamber side surface of the cylinder cover wall 3. The outermost cooling hole 12a is formed deeply downward into the range of the lower ridge 5 of the cylinder cover wall 3.In the illustrated embodiment, the cooling holes 12,1
2a is constructed as a cylindrical hollow chamber with an approximately semicircularly curved bottom 14. This bottom 14 may have a circular shape. Due to the circular cross section of the cooling hole, it is possible to form the cooling hole using a drilling machine and a milling machine. Insofar as the cylinder cover wall 3 is manufactured by casting, it is also possible for the cross-sectional shape of the cooling holes to be oval, square or hexagonal, for example. It is also advantageous if the cooling holes have two cross-sectional divisions that are symmetrical with respect to the central longitudinal plan view 81B (FIG. 2). Each circulation hole 11 is a Sekiguchi web 1 of the cooling hole 12.
It is arranged so as to lead to one Ayabe area close to 3. A green area facing this area approximately diametrically opens into a straight outflow passage 16 . In this case, the outflow passage 16 is partitioned by the skin of the rib 1.
The cross-sectional area of the area of the cooling holes 12 , 12 a that communicates with the exit channel 16 is designed to be significantly larger than the cross-sectional area of the flow hole 11 . Further, the cross-sectional area of the outflow passage 16 is determined by a series of cooling holes 12 located along the outflow passage 16,
This corresponds to the sum of the outflow cross-sectional areas of 12a. The individual outlet channels 16 themselves are connected to a common outlet line 17 without any throttling effect. An annular cooling passage wheel 9 is further provided on the inner edge of the cylinder cover wall 3 surrounding the injection nozzle 18 .
A large number of communication holes 11a also communicate therewith. In the illustrated embodiment, a plurality of cooling holes 20 are formed in the collar 21 of one cylinder liner 22 .

Since the mechanical stress on the immovably fixed collar 21 is smaller than the mechanical stress on the cylinder cover wall 3 due to the gas force exerted from the combustion chamber 1, the cooling hole 20 is closed as shown in FIG.
Preferably, the longitudinal axis of the cylinder liner 22 is inclined at a relatively small angle with respect to the inner surface of the cylinder liner 22. Cooling water is supplied to this cooling hole 20 from one chamber 23 through one narrow circulation hole 24, and this circulation hole 24 itself is one of the closed holes of the cooling hole 20.
It leads to two green areas. A green area approximately diametrically opposite to the edge area of this gate leads into an annular outflow channel 25 which itself is connected to a discharge line (not shown). has been done. During use of the cylinder head described above, coolant enters into the chambers 6 and 23.

The coolant flows from the chambers 6, 23 through the flow holes 1, 11a, 24 while simultaneously decreasing its pressure and increasing its velocity. The cooling liquid flows from the circulation holes 11, turtle a, and 24 to individual cooling holes 12920 as shown by the arrows in FIG.
reaches bottom 14. The cooling fluid is then drawn 180 degrees within the cooling holes 12, 20 by the bottom 14, which is curved in a generally semi-circular manner.
It then turns around and flows into outflow passages 16, 25 which extend in a direction substantially perpendicular to the flow direction. Outflow passage 16
, 25, the cooling liquid flows into the discharge line 17. The piston shown partially in FIGS. 3 and 3 consists of a piston head 30 and a piston body 31.

A large number of cooling holes 32 are formed in the central region of the piston head 30, and the longitudinal axis C-C of these cooling holes 32 forms an angle of about 60 degrees with respect to the surface of the piston head 30 on the combustion chamber side. ing. A large number of cooling holes 32a other than the cooling holes 32 are formed in the green area of the piston head 30, and the axes of these cooling holes 32a are aligned with the piston head 30.
It extends almost perpendicular to the combustion chamber side surface of the combustion chamber. The cooling holes 32, 32a have a circular cross section and a semicircularly curved bottom 35. series of cooling holes 32
or between the innermost row of such cooling holes 32 and 1
Webs 37 remain between the two central cooling chambers 36, and these webs 37 not only increase the heat dissipation surface but also increase the mechanical strength of the piston head.
The piston body 31', which is connected to the piston head 30' by a fastening bolt 38, has a central chamber 39 into which a coolant supply pipe 40 leads.

One surrounding wall 41 of this central chamber 39 that is parallel to the opening plane of the cooling hole 32 has ribs 42, and circulation holes 43 are also formed inside these ribs 42. Each of the holes 43 is one of the openings □ of each cooling hole 32.
It leads to the Ayabe area. In this case, the rib 42 protrudes just before the Sekiguchi plane of the cooling hole, and the piston longitudinal axis D-
It extends almost radially with respect to D. The space left between the numerous ribs 42 is the outflow passage 4 leading to the discharge pipe 45.
4.

The central chamber 39 is connected to the cooling chamber 36 via one cooling passage 46 , from which one annular passage 4 is connected.
7 communicates with the outflow passage 44 . A number of radial cooling passages 48 lead from the central chamber 39 into an annular cooling passage 49 for supplying cooling liquid to the cooling holes 32a.

A number of flow holes 58 extend upwardly from this cooling channel 4g, through which the cooling liquid flows into a closed twill region of each cooling hole 32a. One collection chamber 51 is provided below the connection port plane of the flow hole 50, that is, the connection port plane that reaches almost within the entrance plane of the cooling hole 32a. It is connected to the discharge pipe 45 via. With this piston, the cooling liquid is supplied into the central chamber 39 through the supply pipe 48.

A portion of the cooling liquid from this central chamber 39 flows into the cooling chamber 36 through cooling passages 46 . Cooling passage 46 is designed such that the coolant flowing into cooling passage 36 will experience a significant pressure drop. In this case, a coolant flow passes through the cooling channel 46 at high speed and is guided along the back side of the piston head to be cooled and flows via the annular channel 47 into the outlet channel 44. The portion flows into the cooling hole 32 through the flow hole 43, is guided down one green area of the closure of the cooling hole 32 to the bottom 35, as shown by the arrow, and then turns around and flows back through the opposite green area. The closed openings of the individual cooling holes 32 communicate with outflow passages 44 located on both sides of the ribs 42 and are approximately perpendicular to the direction of return of the coolant in the cooling holes 32. In this case, the flow holes 47 are It is designed such that the coolant partial flow guided by the cooling channels 46 has a constant low pressure in these flow holes 47, i.e. another cooling guided by the flow holes 43 into the cooling holes 32. It is designed in such a way that the liquid sub-stream will exhibit a pressure equal to the pressure it has after exiting the cooling holes 32.
8 and the annular cooling passage 49 and the flow hole 50 into the cooling hole 32a, then collecting in the collecting chamber 51' and flowing out through the outlet passage 52 into the discharge pipe 45.

[Brief explanation of the drawing]

Fig. 1 is an axial sectional view showing a part of the cylinder head and cylinder liner, Fig. 2 is a sectional view taken along the 0-Ro line in Fig. 1, Fig. 3 is an axial sectional view of the upper part of the piston, and Fig. It is a sectional view taken along the line N-W in the figure. j...W combustion chamber, 2...piston, 3...
...Cylinder cover wall, 4..."Cylinder cover housing, 5...Tightening bolt, 8...Inflow port, 10..."
Rib, 11... Distribution hole, 12, 12a... Cooling hole, turtle 3
...web, 14...bottom, 16...outflow passage, stove 7...
Discharge pipe, Turtle 8... Injection nozzle, 19... Cooling passage 20... Cooling hole, 22... Silling liner, 24... Distribution hole, 25... Outflow passage.Fi 9.3

Claims (1)

[Scope of Claims] 1. A structural part having a wall subjected to thermal loads in an internal combustion engine, such as a cylinder head or a piston, comprising:
It has two cooling chambers separated by an intermediate wall, and the cooling liquid is to be cooled by flowing from the outer cooling chamber into the inner cooling chamber with a pressure reduction through a number of thin flow holes in the intermediate wall. In the type where the inner cooling chamber is connected to one outlet pipe, the wall 3 to be cooled is
21, 30 are a number of cooling holes 12, 12a, 20, 3 formed as cylindrical hollow chambers, leaving the webs 13, 37.
2, 32a, and the inflow of the cooling liquid is directed towards an area near the web within these hollow chambers;
The hollow chamber includes an outflow passage 16, which is formed in a direction transverse to the flow direction of the cooling liquid in at least a part of the area near the web, and is connected to the discharge pipes 17, 45.
25, 44, 51, and the flow from the communication holes 11, 24, 43, 50 toward one of the two cross-sectional divided portions symmetrical with respect to the central axis plane of the hollow chamber. Structural part with a wall subjected to thermal loads in an internal combustion engine, characterized in that the inflow of the coolant is directed and the other cross-sectional division opens into an outflow channel 16, 25, 45, 51. 2. Structural part according to claim 1, in which a number of parallel hollow chambers open into a common outflow channel (16, 44). 3. The flow holes 11, 43 are formed in the ribs 10, 42 of a structural part 4, 31, which are fixedly connected to the wall 3, 30 to be cooled, and which extend approximately to the opening plane of the cavity. A structural part according to any of the preceding claims. 4 The flow cross-sectional area of the discharge pipes 17, 45 is the same as that of the flow holes 11, 2.
A structural part according to any one of the preceding claims, which is designed to be larger than the sum of the 4, 43 and 50 individual cross-sectional areas.