GB2508472A - Sealing Element for a cooling Jacket of a Combustion Engine - Google Patents

Abstract

The invention relates to a combustion engine comprising a cooling jacket 4 arranged between a cylinder liner 5 and a cylinder block 3 housing the liner 5, which is sealed by a seal element 1 and comprising a cylinder head gasket 8, which is clamped by a contact force (16, fig.6b) between a cylinder head 7 and the cylinder housing 3. Moreover a backup ring 10 is envisaged which at least partially encloses the seal element 1, via which the seal element 1 is deformable by means of the contact force (16, fig.6b) for the cylinder head gasket 8. The seal 1 may be a graphite seal and the backup ring 10 may have a latch element for fixing to a latch area 13 of the cylinder liner 5. The seal can provide a better sealing arrangement across a wider and higher temperature range.

Description

Seal Element for a Combustion Engine The invention relates to a combustion engine comprising a cooling jacket arranged between a cylinder liner and a cylinder block housing the same, which is sealed by a seal element, and comprising a cylinder head gasket, which is clamped by a contact force between a cylinder head and the cylinder block.

It can be gathered as known from the prior art that such seal elements are commonly designed as conventional seal rings formed from an elastomer. These seal rings prevent leaking of cooling water from the cooling jacket and consequently keep the cooling water from contacting the cylinder head gasket or the cylinder head. The sealing rings also prevent cooling water from entering a combustion chamber of the combustion engine that would otherwise, due to the incompressibility of the cooling water, create a so-called hydraulic shock resulting in severe engine damage. Some manufacturers of modern heavy duty diesel combustion engines employ so-called "Mid-Stop or "Bottom-Stop" cylinder liners, which can be exchanged in cases of wear or damage.

In this connection one refers to a "Mid-Stop" cylinder liner if this cylinder liner is received in the center portion of its outer surface by means of a positioner to the cylinder housing, and to a cylinder "Bottom-Stop" cylinder liner if the corresponding positioner of the cylinder liner is arranged at its distal end furthest away from the cylinder head.

Accordingly a cylinder liner designed as a so-called Top-Stop" cylinder liner has a positioner arranged in the vicinity of the cylinder head. Above all "Mid-Stop,, and "Bottom-Stop" cylinder liners require such deformable elastomeric seal rings, which are arranged in the vicinity of the cylinder head between the cylinder liner and the cylinder block, to prevent a leaking of the cooling water from the cooling jacket.

An example for sealing a so-called Mid-Stop cylinder liner may be gathered as known from DE 696 18 308 T2, wherein a seal element designed as a seal ring is arranged between a cylinder liner and a cylinder block in this place, in order to prevent leakage of cooling water.

In the course of improving effectiveness engine manufacturers tend to steadily increase cylinder pressures of combustion engines, whereby also the temperature in the area of these seal elements continuously rises, since an increasing cylinder pressure also involves a raised cylinder temperature. As a result of increasing cylinder pressures the standard high-performance operation temperature limits, which presently are at about 190°C, can be reached and even exceeded, whereby leakages in the area of the seal elements may occur.

It is the task of the present invention to provide a combustion engine of the initially mentioned kind, in which across a particularly wide temperature range a leakage of cooling water is prevented.

This task according to the invention is solved by a combustion engine having the features of claim 1. Advantageous embodiments with expedient further developments of the invention are indicated in the remaining claims.

In order to provide a combustion engine of the initially mentioned kind, in which the leaking of cooling water is reliably prevented across a particularly wide temperature range, according to the invention a backup ring is provided, via which the seal element is deformable by means of the contact force for clamping the cylinder head gasket. This means that a particularly high tightness of the seal element is achieved, in that the backup ring transmits at least part of the contact force for clamping the cylinder head gasket to the seal element and the seal element thereby exerts a particularly high contact force upon a seal seat associated with the seal element. Instead of the sealing known from the prior art produced as a consequence of a deformation by way of a radially acting contact force, as it is common with elastomeric seal rings, according to the invention there is in addition a contact force acting in parallel to a longitudinal axis of the cylinder liner a contact force exerted upon the seal ring, by means of which contact force the seal ring is particularly heavily deformed and as a consequence of which a leakage of cooling water is prevented in a particularly effective way.

Further advantages, features, and details of the invention may be gathered from the following description of a preferred embodiment as well as from the drawings.

The drawings show in: Fig. 1 a schematic sectional view of a portion of a combustion engine, which has a cooling jacket delimited by a cylinder block and a cylinder liner, wherein the cooling jacket is sealed against leakage of cooling water by means of a

conventional seal ring known from the prior art;

Fig. 2 a schematic sectional view of the portion of the combustion engine, wherein conventional seal ring shown in Fig. 1 has been substituted by a seal element, which rests on a cylinder head gasket and as a consequence of a contact force of the cylinder head gasket seals the cooling jacket against leakage of cooling water; Fig. 3a a schematic sectional view of the combustion engine, wherein the cylinder head gasket and a backup ring rest on the seal element arranged in a groove area; Fig. 3b a schematic sectional view of the portion of the combustion engine, wherein the seal element by means of the contact force transmitted by the backup ring and serving for mounting the cylinder head gasket, seals the cooling jacket against leakage of cooling water; Fig. 4a a schematic sectional view of a portion of the backup ring, which in the present case has a latch element for latching to a latch area associated with the cylinder liners; Fig. 4b a schematic sectional view of the portion of the cylinder liner, to the latch area of which the backup ring is fixed by means of its latch element; Fig. 4c a schematic detailed view of the latch element fixed to the latch area; Fig. 4d a schematic detailed view of the backup ring latched to the latch area, on which in the present case the cylinder head as well as the cylinder head seal rest; Fig. 4e a schematic detailed view of the latched backup ring, which clamps the seal element as a consequence of the contact force; Fig. 5a a schematic sectional view of the portion of the backup ring, which has the latch element in an embodiment, which is alternative to that of Fig. 4.

Fig. 5b a schematic detailed view of the latch area having an alternative design in comparison with that of Fig. 4c, to which latch area the backup ring shown in Fig. 5a is fixed; Fig. 5c a further schematic sectional view of the portion of the backup ring, wherein a proportion of the backup ring and the seal element differs from the proportion shown in Fig. Sa; Fig. 5d a further schematic detailed view of the latch area having an alternative design in comparison to that of Fig. 4c, to which latch area the backup ring shown in Fig. 5c is fixed; Fig. Ga a schematic view of the portion of the backup ring, which in the present case has a steel cap and encloses the seal element partially; Fig. Gb a schematic detailed view of a latch area of an alternative design, to which the backup ring shown in Fig. 6a is fixed; Fig. Gc a further schematic detailed view of the backup ring latched to the latch area according to Fig. 6a; and Fig. Gd a further schematic detailed view of the latched backup ring from Fig. Ga, which is fixed to the latch area and is clamped by means of the contact force.

In the Figs. the same elements and elements having the same function are equipped with the same reference signs.

Fig. 1 shows a sectional view of a portion of a combustion engine, which has a cooling jacket 4 delimited by a cylinder block 3 and a cylinder liner 5. The cooling jacket 4 is sealed against leaking of cooling water 9 contained in the cooling jacket 4. The conventional seal ring 2 is received in a groove area 11 between the cylinder block 3 and the cylinder liner 5. On a side of the cylinder liner 5 facing away from the cooling water 9 a piston 6 of the combustion engine is mounted to be capable of being axially movable along the cylinder liner 5. The piston 6 together with the cylinder linerS and a cylinder head 7 forms a combustion chamber 19 of the combustion engine, wherein merely portions of the combustion space 19 in Fig. 1 are shown.

Whilst exerting a contact force 16 a cylinder head gaskets is clamped in a sealing manner both between the cylinder head 7 and the cylinder liners and between the cylinder head 7 and the cylinder block 3. For operational reasons the cylinder head 7 has a so-called cast expansion slot 15. By means of the cylinder head gasket B a leaking of the working medium from the combustion chamber is effectively prevented, in contrast to which by means of the conventional seal ring 2 a leaking of the cooling waterY from the cooling jacket 4 is avoided. According to the prior art the conventional seal ring 2 is clamped in a groove area 11, whilst exerting a radial contact force. Since the conventional seal ring 2 in a common design is formed from a polymer, a leakage of the cooling water 9 under particularly high thermal stress of the conventional seal ring as a consequence of high pressures and/or temperatures in the combustion chamber 19 cannot be prevented in an operationally secure way.

The subsequent figures essentially contain the details already explained with reference to Fig. 1, for which reason in the following merely the differences are set out.

Fig. 2 is a sectional view of the portion of the combustion engine that shows a further embodiment, wherein a seal element 1 is deformable by means of a contact force 16 for clamping the cylinder head seal B. The contact force 16 is exerted in that the cylinder head 7 (not shown in Fig. 2) is screwed together with the cylinder block 3 and thereby the cylinder head seal 8 is clamped. By way of exerting the contact force 16 and by the deformation of the seal element 1 resulting therefrom, as can be seen in the present case in Fig. 2, the conventional seal ring can be substituted by the seal element 1, where in particular in the embodiment shown in Fig. 2 the groove area 11, not having the conventional seal ring 2, remains clear.

Fig. 3a in a further embodiment equally shows a sectional view of the portion of the combustion engine, where in the present case the cylinder head gasket 8 and a backup ring 10 rest on the seal element 1 arranged in the groove area 11. In contrast to Fig. 1 and Fig. 2 the groove area 11 in Fig. 3a and the figures described subsequently is accessible along a mounting direction 18, which extends essentially in parallel to a longitudinal axis of the cylinder liner 5. In other words the seal element 1 can be slid along the mounting direction 18 into the groove area 11, where in contrast to the groove area 11 shown in Fig. 1 and Fig. 2 it can essentially be done without a radial expansion of the seal element 1. This is particularly advantageous, since the ring-shaped seal element is designed as a graphite seal, which in the radial direction has a lower expandability than the conventional seal ring 2 formed from an elastomer.

Upon introduction of the seal element 1 into the groove area 11 along the mounting direction 18 now, to start with, the equally ring-shaped backup ring 10 is placed along the mounting direction 18 upon the seal element 1. If now the cylinder head gasket 8 is placed upon the backup ring 10, a deformation distance 17 is formed. The deformation distance 17 in this connection corresponds to a distance of a bottom surface of the cylinder head gasket 8 resting on the backup ring 10 and a top surface of the cylinder block 3 facing the bottom surface of the cylinder head gasket 8.

Fig. 3b shows a sectional view of the portion of the combustion engine, wherein the seal element 1 by means of the contact force 16 transmitted by the backup ring 10 seals the cooling jacket 4 against leakage of cooling water. From the combined view of Fig. 3a and Fig. 3b it can now be seen that as a consequence of fixing the cylinder head 7 (not shown) to the cylinder block 3 the contact force 16 for clamping the cylinder head gasket 8 is transmitted at least partly by means of the backup ring 10 to the seal element 1, whereby this as a consequence is deformed by the deformation distance 17. The backup ring 10 in this connection is advantageously designed as a steel ring and also serves for distancing the seal element 1 from the cylinder head gasket 8, i.e. for preventing contact between the cylinder head gasket 8 and the seal element 1 designed as a flexilbe graphite seal. Thereby it is possible to conduct maintenance work on the cylinder head gasket 8, without interfering with the seal element 1 in its placement in the groove area 11. In that the seal element 1 as a consequence of the conveyance of the contact force 16 is deformed by the backup ring 10 by the deformation distance 17, leakage of the cooling water 9 from the cooling jacket 4 in the direction of the cylinder head gaskets is prevented particularly effectively. By way of the deformation the seal element 1 is pressed particularly strongly into the groove area 11.

In the course of the assembly of the combustion engine it is required for manufacturing reasons to insert the seal element 1 into the groove area 11 of the cylinder liner 5 prior to the cylinder liner being mounted in the cylinder block 3. In order to now ensure that the seal element 1 is kept particularly securely in the groove area 11 of the cylinder liner 5, the backup ring 10 in a preferred embodiment has a latch element 12. A possible embodiment of the latch element 12 in a sectional view of a portion of the backup ring 10 is shown in Fig. 4a. In this way it can be seen that the latch element 12 of the backup ring in the present case is designed as a so-called latch lug, where in a latch area 13 of the groove area 11 the latch element 12 can be latched. This latch area 13 is shown in a sectional view of the portion of the cylinder liner 5 according to Fig. 4b.

If now both the seal element 1 and the backup ring 10 in correspondence with the mounting direction 18 are guided in the direction of the groove area 11, the latch element 12 latches into the latch area 13 of the groove area 11, which in the present case is designed as a recess. Thus due to the latching of the latch element 12 into the latch area 13 now the cylinder liner 5 can be fixed within the cylinder block 3, wherein during assembly it is particularly effectively prevented that the seal element 1 slips out from the groove area 11. As already shown with reference to Fig. 3a, in the latched position of the latch element 12 in the groove area 11 equally a deformation distance 17 is effected, by which the seal element 1 is deformable as a consequence of performance of the contact force 16. This derives in particular from a further detailed view of the latch element 12 fixed to the latch area 13 according to Fig. 4c.

Fig. 4d shows a further detailed view of the latched-in backup ring 10, on which in the present case rests the cylinder head 7 as well as the cylinder head gasket 8. In Fig. 4e a detailed view of the latched-in backup ring 10 is shown, which equally has the latch element 12 and clamps the seal element 1 as a consequence of the contact force 16.

From the combined view of Fig. 4d and Fig. 4e it can be seen that on the one hand the deformation distance 17 for deformation of the seal element 1 is provided and on the other hand the latch element 12 corresponds in such a way with the latch area 13 that travelling the deformation distance 17 an unhindered deformation of the seal element 1 is facilitated. In other words, this means that whilst the latch element 12 prevents an undesired slipping out of the seal element 1 and of the backup ring 10 fixing the seal element 1 in the groove area 11 in a direction contrary to the mounting direction 18, a deforming of the seal element 1 whilst the contact force 16 is exerted is possible without the latch element 12 colliding with the latch area 13 and thus obstructing the deformation of the seal element 1.

Fig. 5a and Fig. Sc each show a sectional view of a portion of the backup ring 10 each in an alternative embodiment. Both in Fig. 5a and Fig. 5c the respective backup rings 10 are of a symmetrical design, wherein as a consequence of the symmetry the respective backup rings 10 each have two of the latch elements 12, which are arranged opposite to each other. By this symmetrical and opposite arrangement of the two latch elements 12 the backup ring 10 can be mounted in a particularly operationally reliable way, since the backup ring 10 could equally well be reversed, whereby instead of the one of the two latch elements 12 the other oppositely arranged latch element 12 would engage the latch area 13. Thus an incorrect mounting of the backup ling 10 is rendered impossible. This can be seen in particular from a combined view of the Fig. 5b and the Fig. 5d, wherein Fig. 5b shows a detailed view of the latch area 13, which in the present case is adjusted to the two latch elements 12 according to Fig. 5a.

Fig. 5d equally shows a detailed view of the latch area 13, which however in the present case is adjusted to the two latch elements 12 shown in Fig. 5c. The backup ring 10 and the seal element 1 in their assembled position in Fig. 5a have a height 20 and in Fig. 5c a height 21. In this connection, as derives in particular from the combined view of Fig. 5a and Fig. 5c, on the one hand it is possible to reduce or increase the height of the backup ring 10, and to adjust the height of the seal element 1 to the change in height of the backup ring 10 in such a way that the height 20 and the height 21 each have identical amounts. Accordingly, it is also possible for instance either to increase the height of the backup ring 10 and to reduce the height of the seal element 1, or else to increase the height of the seal element 1 and to reduce the height of the backup ring 10 at the same time, where in both cases the common height 20 or the height 21 are kept the same.

Whilst by keeping the height 20 or the height 21 the same during assembly of the seal element 1 the same deformation distance 17 is available in each case, however, as may be gathered in particular from Fig. 5b and Fig. 5d, the seal element 1 is deformed to different degrees in each case. For instance the seal element 1 shown in Fig. Sb is pressed together, i.e. deformed by 40 % of its height, and the seal element 1 shown in Fig. Sd for instance merely by 10 %. In order to achieve the respective deformation, also the contact force 16 differs in both cases. Consequently, also the respective seal elements 1 shown in Fig. 5b and Fig. 5d, respectively are pressed into the groove area 11 to different degrees, whereby in a particularly advantageous way the contact force 16 can be adjusted in dependency on the respective operational conditions of the combustion engine.

It is clear that the height 20 according to Fig. 5a and the height 21 according to Fig. 5c may also have different values, wherein it is in particular possible to compensate for respective component tolerances by a corresponding adjustment of the height of the clamp element 10 or the seal element 1.

Fig. 6a shows a schematic sectional view of the portion of the backup ring 10, which in the present case has a steel cap 14 and encloses the seal element 1 at least partially. In other words the backup ring 10 shown in Fig. 6a has an outline that is designed as a half-shell in the form of a U-section, and encloses the seal element 1 at least partially. The lateral walls of the backup ring 10 in this setup are elastically deformable, whereby the forces required for latching the latch element 12 into the latch area 13 can be reduced. It has been contemplated that instead of latch element 12 being fully continuous, it could instead be comprised of at least two tabs or segments. Breaking latch element 12 into sized sections separated for instance by small slits within the circumference would further reduce the force necessary for latching latch element 12 into latch area 13, which can also facilitate manual assembly. The fact that the backup ring 10 encloses the seal element 1 at least partially helps to avoid disadvantageous deformations of the seal element 1, e.g. upon application of the contact force 16 in other embodiments, the seal element 1 could deform upwards around or beyond the bottom portion of the backup ring.

Seal element 1 can be formed of flexible graphite..

Fig. Gb and Fig. 6c each show a detailed view of the backup ring 10 described in Fig. Ga, which is inserted into the groove area 11, which in turn has a latch area 13 that is adjusted to the latch element 12. Accordingly in Fig. Gd in a further detailed view it is shown how the backup ring 10 having the embodiment shown in Fig. 6a is pressed into the groove area 11 whilst exerting at least part of the contact force 16 and thus seal element 1 is deformed.

List of reference signs 1 seal element 2 conventional seal ring 3 cylinder block 4 cooling jacket cylinder liner 6 piston 7 cylinder head 8 cylinder head gasket 9 coolant backup ring 11 groove area 12 latch element 13 latch area 14 steel cap cast expansion slot 16 contact force 17 deformation distance 18 mounting direction 19 combustion chamber height 21 height

Claims (6)

1. Claims A combustion engine comprising a cooling jacket (4) arranged between a cylinder liner (5) and cylinder block (3) housing the same, which is sealed by a seal element (1), and comprising a cylinder head gasket (8), which is clamped by a contact force (16) between the cylinder head (7) and the cylinder housing (3), characterized in that a backup ring (10) is envisaged, via which the seal element (1) is deformable by means of the contact force (16) for clamping the cylinder head gasket (8).
2. 2. The combustion engine according to claim 1 characterized in that the backup ring (10) encloses the seal element (1) at least partially.
3. 3. The combustion engine according to claim 1 or 2, characterized in that the seal element (1) is arranged in a groove area (11) between the cylinder liner (5) and the cylinder block (3).
4. 4. The combustion engine according to any one of claims 1 to 3, characterized in that the seal element (1) is designed as a graphite seal.
5. 5. The combustion engine according to any one of claims 1 to 4, characterized in that the cylinder liner(S) has a latch area (13).
6. 6. The combustion engine according to claim 5, characterized in that backup ring (10) has a latch element (12) for fixing to the latch area (13) of the cylinder liner (5).