JP2004003446A - Reciprocating internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the cooling of an upper area of a thermally hazardous cylinder liner. <P>SOLUTION: An annular chamber 11 is divided into a lower chamber 11a including a refrigerant inlet 12 and an upper chamber 11b including a refrigerant outlet 13 by an intermediate ring 15 located below the refrigerant outlet 13 to bridge the internal width of the annular chamber, and the intermediate ring 15 has a flow passage 16 for a refrigerant which is uniformly distributed over the circumference of the intermediate ring 15. The inner limit of the radial direction of the flow passage 16 is a cylinder liner 2 at least in the upper area of the intermediate ring 15, and the upper area of the cylinder liner 2 exposed to a high temperature load is excellently cooled by providing a minimum full section to the plane of the intermediate ring 15 at least on the outlet side. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention includes a cylinder liner comprising at least one cylinder and containing an associated piston, comprising a radial flange at an upper end of the cylinder liner, surrounding the cylinder liner at a radial distance and having a radial flange. A reciprocating internal combustion engine, especially a large diesel engine, which has a cooling-capable, annular-shaped chamber with at least one refrigerant inlet in the lower region and at least one refrigerant outlet in the upper region, with an abutting cooling jacket. About.
[0002]
[Prior art]
During operation of the reciprocating internal combustion engine, particularly high temperature loads occur in the upper region of the cylinder liner. This area of risk must therefore be cooled intensively to avoid thermal overload. Conventionally, this is achieved by providing a cooling hole or passage in which the upper region of the cylinder liner exits the transition region between the radial flange and the cylinder liner and communicates with the annular chamber, which allows the coolant. Has been realized. However, this type requires relatively high production costs and nevertheless provides only a limited cooling effect. That is, in this connection, the refrigerant circulates through the annular chamber at a relatively low speed, and the heat removal from the hazardous area takes place essentially only by natural convection, which proceeds very slowly. I do.
[0003]
[Problems to be solved by the invention]
Given the above, it is therefore an object of the present invention to improve the cooling of the upper region of the cylinder liner, which is particularly dangerous.
[0004]
[Means for Solving the Problems]
According to the present invention, the invention provides, in accordance with the invention, an annular chamber in which a lower chamber containing a refrigerant inlet and a chamber containing a refrigerant outlet are provided by an intermediate ring positioned below the refrigerant outlet bridging the inner width of the annular chamber. An intermediate ring having a flow passage for the refrigerant distributed around the circumference of the intermediate ring, the radial inner restriction of the flow passage being at least in the upper region of the intermediate ring by a cylinder liner. And is solved by having a minimum total cross section at least on the outlet side relative to the plane of the intermediate ring.
[0005]
The refrigerant arriving from below through the flow passage is accelerated strongly inside the flow passage due to the minimum overall cross-section of the flow passage relative to the cross-sectional plane of the annular chamber interrupted by the intermediate ring. The flow passage then constitutes the nozzle from which the coolant jet having a substantially higher velocity flows out. Thus, above the intermediate ring, there is a refrigerant flow assigned to the cylinder liner, near the wall, which produces relatively fast and effective heat dissipation. This coolant then flushes the outer surface of the area of the dangerous cylinder liner mentioned above, whereby the cylinder liner is cooled down, so that a high level of safety is achieved. The intermediate ring according to the invention can be manufactured relatively simply and cost-effectively. Another advantage is that the intermediate ring according to the invention can be used without substantially changing the structure of the cylinder arrangement. Thus, in an advantageous manner, it is possible to retrofit the intermediate ring according to the invention in an existing arrangement, and thus improve the cooling of areas which are particularly dangerous with regard to thermal shock. The measures according to the invention also result in correspondingly excellent economics.
[0006]
Advantageous embodiments and expedient developments of the prioritized measures are set out in the dependent claims. In this way, the intermediate ring can be expediently arranged at the top dead center of the piston in the range of the height of the piston ring at the top of the piston. This ensures that the region to be centrally cooled is precisely assigned to the region that is particularly thermally thermally loaded.
[0007]
Another advantageous measure is that the intermediate ring is adjustable at altitude. This guarantees that the intermediate ring can be brought into a position suitable for optimal cooling as well as optimal flushing of the area at risk.
[0008]
In another development of the prioritized measure, the upper, inner corner area of the upper chamber containing the refrigerant outlet, which is limited by the cylinder liner and its flange, the refrigerant flowing out of the flow passage of the intermediate ring It is formed such that an arcuate redirection of the flow occurs. This results in particularly good heat transfer with turbulence.
[0009]
Advantageously, the cylinder liner may have an outer periphery that expands conically downward at least in the area associated with the intermediate ring, and an inner periphery corresponding to the intermediate ring. As a result, a firm seat of the intermediate ring can be achieved in a radially and axially downwardly extending direction with positive support. The intermediate ring must therefore be supported only on the top. For this purpose, advantageously an adjustable spacing device can be provided which can be carried against the flange of the cylinder liner. This allows for optimal position adjustment.
[0010]
Another expedient measure is that the diameter of the intermediate ring is variable. This advantageously allows axial adjustability even in relation to the conical seat of the intermediate ring.
[0011]
According to another development of the priority measures, the intermediate ring can preferably be composed of a plurality of segments which can be connected to one another by springs. This allows for simple assembly and adjustment of the intermediate ring in an advantageous manner. Alternatively, the intermediate ring may be formed according to the form of an extendable piston ring.
[0012]
In the multi-segment configuration of the intermediate ring, between the ends of the segments respectively facing each other, one upwardly protruding upper side and lower side of the segment, each of which can be screwed to the flange of the segment provided thereat A connection plate may be accommodated. In this case, a high stability of the intermediate ring occurs. Nevertheless, since the connecting plate can function as a spring, extension is possible. Furthermore, it is possible to change the diameter of the intermediate ring by changing the thickness of the connecting plate.
[0013]
Another advantageous measure can consist in that the smallest cross section of the flow passage has an inner width of at least 1.0 to 1.5 mm. In this way, clogging by impurities carried by the coolant can be reliably avoided.
[0014]
In another development of the preferred measures, the minimum cross section of the flow passage is selected to produce a flow velocity of at least 3 m per second. Experience has shown that a particularly good nozzle action and a particularly reliable cooling of the area at risk can be achieved thereby.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Further preferred embodiments and expedient developments of the prevailing measures are set out in the remaining dependent claims and can be read in more detail from the following description of embodiments with reference to the drawings.
[0016]
The main field of application of the present invention is large engines, especially two-cycle large diesel engines, such as those used, for example, as marine drives. Such engines usually have a plurality of cylinders arranged in rows, of which only a part is shown in FIG. The cylinder 1 on the basis of FIG. 1 has, in a manner known per se, a piston 3 which cooperates with a crankshaft (not shown), together with a cylinder cover 4 housed on a cylinder liner 2, in a manner known per se. It includes the cylinder liner disposed within the liner 2. The piston 3 has a piston ring 6 that abuts the inner circumference of the cylinder liner 2.
[0017]
The cylinder liner 2 has a radial flange 7 connected to the upper end of the cylinder liner, at the outer periphery of which a cooling jacket 8 surrounding the cylinder liner 2 at radial intervals abuts the upper end. For this purpose, the cooling jacket 8 has an axial abutment surface cooperating with a parallel opposing surface 9 of the flange 7, the latter being provided on the flange side and having a resilient sealing ring 10 in front of the opposing surface 9. Is provided with the contact surface. The cooling jacket 8 surrounds the cylinder liner 2 and limits the annular chamber 11 which is sprayed with cooling liquid for cooling the cylinder liner 2. This is supplied via an inlet 12 provided in the lower region of the annular chamber, as indicated by the arrow, and is discharged via a discharge opening 13 arranged in the region of the upper end of the annular chamber 11. It has a relatively small cross section relative to the cross section of the annular chamber 11, resulting in a relatively low through-put velocity of the refrigerant inside the annular chamber 11.
[0018]
During operation of the engine, a maximum temperature load on the cylinder liner 2 occurs at the top dead center of the piston 3 above the uppermost piston ring 6. This dangerous area 14 must therefore be cooled particularly well. This results in a relatively fast flow of coolant near the wall in the area outside the cylinder liner 2 associated with the area at risk 14. To achieve this, an intermediate ring 15 is provided in the annular chamber 11 which is positioned directly below the direct outlet opening 13 and which bridges the inner width of the annular chamber. This divides the annular chamber 11 into a lower chamber 11a containing a refrigerant inlet 12 and an upper chamber 11b containing an outlet opening 13, and is provided uniformly in the region of the inner edge of the annular chamber. A flow passage 16 connecting both chambers 11a, 11b distributed over the circumference of the flow passage, the overall cross section of which is relatively small with respect to the annular surface.
[0019]
The intermediate ring 15 abuts on the inner circumference of the intermediate ring at the cylinder liner 2 and cooperates with the cooling jacket 8 like the flange 7 together with the outer circumference of the intermediate ring. Correspondingly, an enclosing elastic sealing ring is provided on the ring side, which at the same time abuts the associated axial surface of the cooling jacket 8 cooperating with the facing surface 18 of the intermediate ring 15 downstream of the sealing ring 17. 17 are provided. The inner circumferential area of the intermediate ring 15 bears against the outer circumference of the cylinder liner 2, resulting in the support of the inner and outer radial intermediate ring 15.
[0020]
In the example shown, the cylinder liner 2 has an outer profile that expands conically downward. The intermediate ring 15 has a corresponding internal contour, which results in a seat-like abutment which prevents the movement of the intermediate ring 15 downwards, which is undesirable.
[0021]
The intermediate ring 15 is positioned such that the intermediate ring is located at the top dead center of the piston 3 in the region of the altitude of the uppermost piston ring 6 of the piston 3. The precise elevation of the intermediate ring and the corresponding distance of the intermediate ring from the flange 7 can be adjusted in a targeted manner. To this end, in the example shown, an adjustable spacer 19 is provided, by means of which the intermediate ring 15 can be supported by the flange 7 which grips the intermediate ring. This can be an adjusting screw for gripping the intermediate ring 15, each of which is associated with one fixing nut. The spacer 19 supports the intermediate ring 15 against an upward force exerted on the intermediate ring by the coolant. A plurality of evenly distributed spacers 19 are provided for the purpose of circumference of the intermediate ring 15. In the example shown, four spacing members 19 are provided so that they can be read from FIGS. 2 and 3. During the formation of the cone on the outside of the cylinder liner 2 and on the inside of the intermediate ring 15, the axial adjustment of the intermediate ring 15 of course requires a corresponding change in the ring diameter.
[0022]
The flow passage 16 is arranged in such a way that a radially inner restriction of the flow passage is formed by the cylinder liner 2 at least in the upper region of the intermediate ring 15. The overall cross-section of the flow passage 16 is, as already indicated above, minimal with respect to the plane of the intermediate ring 15 and correspondingly with respect to the cross-sectional plane of the annular chamber 11 associated with the intermediate ring. The flow passage 16 correspondingly functions as a nozzle, in which the coolant flowing into the nozzle is strongly accelerated. The flow passage 16 correspondingly flows at a high velocity near the wall outside the cylinder liner 2 associated with the dangerous area 14 above the intermediate ring 15, as indicated by the flow arrow 20 in FIG. Creates a coolant flow.
[0023]
The corner area between the cylinder liner 2 and the flange 7, ie the inside corner of the upper part of the chamber 11b, is chamfered, correspondingly forming an arcuate diversion of said flow. In this manner, turbulence is created as indicated by the dotted flow line 21. Overall, a turbulent flow near the wall produces a good heat transfer from the cylinder liner 2 to the coolant, as well as a reliable heat dissipation.
[0024]
The sum of the inward cross sections of all the flow passages 16 is specified such that the nozzle action of the flow passages 16 results in an outgoing jet velocity of at least 3 m / s. This results in excellent cooling of the hazardous area 14, as experiments have shown. The inner width of the flow passage 16 is at least 1.0 to 1.5 mm. In most cases, 1.5 mm is suitable. This avoids clogging of the flow passage due to impurities entrained by the coolant. Nevertheless, it remains at the desired nozzle action.
[0025]
As can be seen in FIG. 2, the flow passage 16 is provided in the region of the inner circumference of the intermediate ring 15 and is uniformly distributed over the circumference, opening inward through the height of the intermediate ring 15. Groove 22 may be formed. In this case, the flow passage 16 is internally restricted by the cylinder liner 2 to the entire length of the flow passage.
[0026]
An alternative formation of the flow passage 16 can be read from FIG. In this case, the intermediate ring 15 is provided with holes 23 which are uniformly distributed over the circumference of the intermediate ring and which are inclined obliquely inward from bottom to top in the radial direction. This means that the hole flows out of the hole in the region of the inner circumference of the intermediate ring 15 and the upper side of the intermediate ring 15 is only slightly chamfered, so that only a small edge recess 24 occurs at that point, The edge recess is not covered by the cylinder liner with the attached intermediate ring 15 and is correspondingly inwardly inclined to form the nozzle opening of the flow passage 16. The lower end of the hole 23 is in the lower region of the intermediate ring 15 which now rises from the inside to the radial outside. The hole 23 can be easily manufactured. At the same time, good nozzle action results with a relatively large inlet opening and a relatively small outlet opening of the flow passage. Furthermore, the inclination of the hole 23 causes a direct wall impact outside the cylinder liner 2 associated with the area at risk 14.
[0027]
In order to realize the rotation of the flow of the cylinder liner 2 in the circumferential direction, the groove 22 or the hole 23 may be inclined in the circumferential direction with respect to the cylinder axis. In the example shown, this is not the case. Here the grooves 22 or holes 23 extend parallel to the cylinder jacket line or parallel to the radial plane containing the cylinder axis.
[0028]
The intermediate ring 15, which may be made of metal or synthetic resin, may be formed according to the form of an extensible piston ring for simple assembly. The implementation is based on the multi-part formation of the intermediate ring 15 so that FIGS. It is composed of a plurality of, here two, segments 25 which can be connected to one another. The segment 25 has an upwardly or downwardly projecting flange 26 in the region of the mutually opposing ends of the segment. It suffices to provide an upwardly projecting flange 26 in the region of the end of one segment 25 and a downwardly projecting flange 26 in the region of the end of the other segment 25. A connection plate 27 projecting upward or downward and being tightened by screws 28 together with a flange 26 provided at that position is provided between the mutually opposite ends of the segment 25. In order to achieve a secure abutment, there is provided an abutment block 29 which is gripped by a screw 28 and which is loose against the segment 25, each facing a flange 26 fixed on the segment side.
[0029]
Said connecting plates, which are each connected to only one segment 25 in the upper or lower edge region of the connecting plate 27, can function as spring elements which allow a radial expansion of the associated intermediate ring 15. Of course, it is also conceivable to provide connection plates 27 of various thicknesses for realizing various ring diameters.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an upper region of a cylinder of a two-cycle large diesel engine.
FIG. 2 is a plan view of an intermediate ring of the arrangement according to FIG. 1;
3 shows a side view of the arrangement according to FIG. 2;
FIG. 4 is an enlarged view of detail A of FIG. 3;
FIG. 5 is a perspective view of a segment of an intermediate ring with a flow passage formed by a hole.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylinder 2 Cylinder liner 3 Piston 4 Cylinder cover 5 Combustion chamber 6 Piston ring 7 Radial flange 8 Cooling jacket 9 Opposite surface 10 Seal ring 11 Annular chamber 11 a Chamber 11 b Chamber 12 Refrigerant inlet 13 Refrigerant outlet 14 Zone 15 Intermediate Ring 16 Flow path 17 Seal ring 18 Opposing surface 19 Spacer 20 Arrow 22 Groove 23 Hole 24 Edge recess 25 Segment 26 Flange 27 Connection plate 28 Screw 29 Contact block

Claims (18)

At least one cylinder (1),
A cylinder liner (2) containing an associated piston (3);
A radial flange (7) is provided at an upper end of the cylinder liner (2), and the radial flange (7) surrounds the cylinder liner at a radial interval.
) With at least one refrigerant inlet (12) in the lower region and at least one refrigerant outlet (13) in the upper region, together with a cooling jacket (8) abutting the cooling jacket (8). In reciprocating internal combustion engines, especially large diesel engines,
A lower chamber (11a) containing said refrigerant inlet (12) by means of an intermediate ring (15) positioned below said refrigerant outlet (13), said annular chamber (11) bridging the inner width of said annular chamber; ) And an upper chamber (11b) containing the refrigerant outlet (13) and the intermediate ring (15) having a flow passage (16) for the refrigerant distributed around the circumference of the intermediate ring. Radially inward of the flow passage is restricted at least in the upper region of the intermediate ring (15) by a cylinder liner (2), at least on the outlet side with a minimum total cross section relative to the plane of the intermediate ring (15). A reciprocating internal combustion engine, comprising: 3. The piston ring according to claim 1, wherein the intermediate ring is arranged at the top dead center of the piston ring within the range of the height of the piston ring on the top of the piston. 2. The reciprocating internal combustion engine according to 1. Reciprocating internal combustion engine according to claim 1 or 2, characterized in that the intermediate ring (15) is adjustable in height. 4. The method according to claim 1, wherein the upper, inner corner region of the upper chamber is formed as an arc-shaped flow diversion of the flow exiting the flow passage. A reciprocating internal combustion engine according to any one of the preceding claims. Reciprocating internal combustion engine according to one of the preceding claims, characterized in that the intermediate ring (15) is supportable by the cylinder liner (2). Characterized in that the cylinder liner (2) has an outer periphery which expands conically downward at least in the area assigned to the intermediate ring (15) and a corresponding inner periphery to which the intermediate ring (15) corresponds. The reciprocating internal combustion engine according to claim 5, wherein 7. The method according to claim 5, wherein the intermediate ring is supported on the radial flange of the cylinder liner by an adjustable spacer. 9. A reciprocating internal combustion engine as described. Reciprocating internal combustion engine according to claim 7, characterized in that the spacing device (19) is formed as a locking screw for gripping the intermediate ring (15). A cooling jacket (8) having an axial sliding surface assigned to said flange (7) and said intermediate ring (15), said sliding surface being provided with one flange-side or intermediate-ring-side seal; A ring (10 or 17) abuts and cooperates with an opposing surface (9 or 18) on the flange side or on the intermediate ring side, which is located after the sealing ring (10 or 17). The reciprocating internal combustion engine according to any one of claims 1 to 8. The reciprocating internal combustion engine according to claim 1, wherein the diameter of the intermediate ring is variable. Reciprocating internal combustion engine according to claim 10, characterized in that the intermediate ring (15) consists of a plurality of segments (25) connectable to each other by springs. The segments (25) each have one upper or lower flange (26) in the region of each opposing end of the segment, one between each end of the opposing segment (25). Two connecting plates (27) are accommodated therein, said connecting plates projecting upwardly above and below said segment (25) and are connectable to a flange (26) provided thereat. Item 12. A reciprocating internal combustion engine according to item 11. Reciprocating internal combustion engine according to claim 10, characterized in that the intermediate ring (15) is formed in the form of an extendable piston ring. Reciprocating internal combustion engine according to claim 10, characterized in that the smallest cross section of the flow passage (16) has an inner width of at least 1.0 to 1.5 mm. The reciprocating device according to claim 1, wherein a minimum cross section of the flow passage is formed such that a flow speed of the refrigerant is at least 3 m / sec. Dynamic internal combustion engine. 16. The method according to claim 1, wherein the flow passage is formed at least partially as a radially inner groove of the intermediate ring. A reciprocating internal combustion engine as described. 17. The flow channel according to claim 1, wherein the flow passage is at least partially formed as a hole in the intermediate ring extending obliquely inward from bottom to top. 18. A reciprocating internal combustion engine according to any one of the preceding claims. 18. Reciprocating internal combustion engine according to one of the preceding claims, characterized in that the flow passage (16) extends parallel to the cylinder jacket line.

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