DK178682B1

DK178682B1 - A large turbocharged self-igniting two-stroke internal combustion engine and a sealing ring therefore

Info

Publication number: DK178682B1
Application number: DKPA201500234A
Authority: DK
Inventors: Arne Kvistgaard Petersen
Original assignee: Man Diesel & Turbo Filial Af Man Diesel & Turbo Se Tyskland
Priority date: 2015-04-15
Filing date: 2015-04-15
Publication date: 2016-11-07
Also published as: KR20160123257A; KR101831388B1; DK201500234A1; JP6209241B2; CN105909422A; JP2016205369A; CN105909422B

Abstract

A large turbocharged two-stroke self-igniting internal combustion engine and a sealing ring therefore. The sealing ring (60) is arranged between the top of a cylinder liner (50) and a cylinder cover (52) in an annular recess with a width (W) corresponding to the width (w) of the sealing ring (60). The annular recess has a depth (d) less than the height (h) of the sealing ring (60) and the sealing ring (60) is partially received in the annular recess (70) with a portion of the height (h) of the sealing ring (60) protruding from the recess (70) and with the sealing ring (60) being secured to the recess (70).

Description

A LARGE TURBOCHARGED SELF-IGNITING TWO-STROKE INTERNAL COMBUSTION ENGINE AND A SEALING RING THEREFORE

FIELD

The present invention relates to a large slow running turbocharged two-stroke internal combustion engine. More specifically the present invention relates to the construction of the sealing between the cylinder liner and the cylinder cover.

BACKGROUND

Large slow running turbocharged two-stroke internal combustion engines are typically used in propulsion systems of large ships or as prime mover in power plants.

Typically, these engines are operated with heavy fuel oil or with fuel oil. Lately, there has been a demand for these diesel engines to be able to handle alternative types of fuel, such as e.g. gas, low flashpoint fuel, coal slurry, petroleum coke and the like.

Due to their enormous size, a misfire or an explosion of fuel in the cylinder can have catastrophic consequences if there is no controlled way for the hot gases to escape. Therefore, all large turbocharged two-stroke self-igniting internal combustion engines are designed such that when the cylinder pressure exceeds a design pressure of the engine the forces on the cylinder cover 52 lift it from the cylinder liner 50 and excess gas is released through the gap between top of the cylinder liner 50 and the cylinder cover 52, cf. Figs. 4,5 and 6. A sealing ring 60 is placed between the top surface 51 of the cylinder liner 50 and the bottom surface 53 of the cylinder cover 50 in order to provide a proper seal under normal operating conditions.

This sealing ring 60 is typically a soft iron ring. During installation of the sealing ring 60 it is loosely placed on top the substantially flat top surface 51 of the cylinder liner 50 and is positioned correctly by a few minor guide hooks 55 that fit into corresponding recesses in the cylinder liner 50, as shown in Fig. 5.

When the cylinder cover 52 has been tightened to the cylinder liner by the cylinder cover studs the sealing ring 60 is kept in place by friction.

If a cylinder cover lift event occurs there is no friction holding the sealing ring in place, and thus a part of the sealing ring 60 will normally be shot out through the gap between the cylinder cover 50 and cylinder liner and into the engine room.

This has several disadvantages. First of all there is the danger to the crew being injured by parts of the sealing ring 60 being shot into the engine room. Secondly, there is the risk of extensive repair time, since the cylinder cover 52 has to be lifted to replace the sealing ring before engine operation can resume. Thirdly, the tension in the cylinder cover studs will close the gap as soon as the excess gases have escaped and press the cylinder cover 52 with great force to the top of the cylinder liner 50 with parts of the deformed and damaged sealing ring 60 there between, causing damage to the sealing surfaces of the cylinder cover 52 and of the cylinder liner 50, respectively.

DISCLOSURE OF THE INVENTION

On this background, it is an object of the present application to provide an engine that overcomes or at least reduces the problems indicated above.

This object is achieved by providing a large turbocharged two-stroke self-igniting internal combustion engine, the engine comprising: at least one cylinder liner with a cylinder cover on top of the at least one cylinder liner, the cylinder cover having a first surface facing the top of the cylinder liner and the top of the cylinder liner having a second surface facing the cylinder cover, a sealing ring between the first surface and the second surface, the sealing ring having a height and a width between the radially inner side surface of the sealing ring and the radially outer side surface of the sealing ring, the first surface or the second surface being provided with an annular recess with a depth and a width, the width corresponding to the width of the sealing ring, the depth being less than the height and the sealing ring being partially received in the annular recess with a portion of the height of the sealing ring protruding from the recess, and the sealing ring being secured to the recess .

By providing a recess from which a portion of the height of the sealing ring protrudes, and by securing the sealing ring to the recess it can be avoided that a portion of the sealing ring is shot out in the engine room during a cylinder cover lift event and the risk of damage to the components that interact with the sealing ring is also significantly reduced.

According to a first implementation of the first aspect the recess is formed between two concentric annular elevations on the first surface or on the second surface.

According to a second implementation of the first aspect the sealing ring is secured to the recess by a geometrical lock between the sealing ring and the recess. Thus an effective way to securing the sealing ring to the recess is provided.

According to a third implementation of the first aspect the recess has a flat bottom surface and tapering side surfaces that widen towards the bottom surface, and wherein the sealing ring has a top surface and an opposing bottom surface connected by tapering side surfaces that widen towards the bottom surface, and wherein the sealing ring is placed in the annular recess with its bottom surface facing the bottom surface of the annular recess. Thus, an effective geometric lock is provided.

According to a fourth implementation of the first aspect the recess the sealing ring is curved so that its upper surface is convex and its bottom surface is concave and its side surfaces extend substantially parallel when inserting the sealing ring into the annular recess. Thus the geometric lock is effectively applied.

According to a fifth implementation of the first aspect the sealing ring is pressed flat when the cylinder cover is mounted on the cylinder liner, the side surfaces of the sealing ring thereby assuming a tapered configuration matching the tapered configuration of the side walls of the annular recess thereby geometrically interlocking the sealing ring with the annular recess.

According to a sixth implementation of the first aspect the recess the sealing ring and the recess form an annular dovetail joint.

According to a seventh implementation of the first aspect the sealing ring is secured to the annular recess by a press fit connection.

According to an eight implementation of the first aspect the recess the sealing ring is secured to the annular recess by fasteners, such as e.g. bolts.

According to a second aspect the object above is achieved by providing a large turbocharged two-stroke self-igniting internal combustion engine with a sealing ring arranged between the top of a cylinder liner and a cylinder cover in an annular recess with a width corresponding to the width of the sealing ring, the annular recess has a depth less than the height of the sealing ring and the sealing ring is partially received in the annular recess with a portion of the height of the sealing ring protruding from the recess and with the sealing ring being secured to the recess.

According to a third aspect the object above is achieved by providing a soft metal sealing ring for sealing between a cylinder liner and a cylinder cover of a large turbocharged self-igniting two-stroke internal combustion engine, the sealing ring having a top surface and a bottom surface connected by side surfaces, the top surface being convex, the bottom surface being concave, and the side surfaces being substantially parallel.

By providing a sealing ring with a shape that will deform plastically during installation it becomes possible to geometrically lock the sealing ring to a groove in an engine component.

According to a first implementation of the third aspect the soft metal sealing ring is configured to be pressed flat when installed between the cylinder liner and the cylinder cover with the top surface and the bottom surface assuming an essentially flat shape and the side surfaces assuming a tapered configuration that widens towards the bottom surface.

Further objects, features, advantages and properties of the engine and method according to the present disclosure will become apparent from the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present description, the invention will be explained in more detail with reference to the exemplary embodiments shown in the drawings, in which:

Fig. 1 is a front view of a large two stroke diesel engine according to an exemplary embodiment,

Fig. 2 is a side view of the large two stroke engine of Fig. 1,

Fig. 3 is a diagrammatic representation of the large two stroke engine according to Fig. 1,

Fig. 4 is an elevated view on the top of a prior art cylinder liner with a prior art sealing ring placed thereon,

Fig. 5 is an enlarged view of a detail of Fig. 4,

Fig. 6 is a perspective cutaway view of a cylinder liner with a cylinder cover installed thereon with a sealing ring there between,

Fig. 7 is an elevated view on the top of a cylinder liner according to an example embodiment with a sealing ring according to an embodiment placed thereon,

Fig. 8 is a detailed sectional view of an example embodiment showing a cylinder liner with a cylinder cover installed thereon with a sealing ring there between,

Fig. 9 is an elevated view on the top of a cylinder liner according to an example embodiment with a sealing ring according to an embodiment placed thereon,

Fig. 10 is a detailed elevated sectional view of the upper part of a cylinder liner according to an example embodiment,

Fig. 11 is the view of Fig. 10 with a sealing ring according to an example embodiment placed in an annular recess,

Fig. 12 is the view of claim 11 showing the configuration of the sealing ring after it has been pressed flat during installation,

Fig. 13 is an elevated view of the top part of a cylinder liner according to an example embodiment illustrating an access recess,

Fig. 14 is a side view of the top part of the cylinder liner of Fig. 13, and

Fig. 15 is a top view of the top part of the cylinder liner of Fig. 13.

DETAILED DESCRIPTION

In the following detailed description, the large two stroke engine will be described by the example embodiments. Figures 1 to 3 show a large low speed turbocharged two-stroke diesel engine with a crankshaft 42 and crossheads 43. Figure 3 shows a diagrammatic representation of a large low speed turbocharged two-stroke diesel engine with its intake and exhaust systems. In this example embodiment the engine has six cylinders 1 in line. Large turbocharged two-stroke diesel engines have typically between five and sixteen cylinders in line, carried by an engine frame 45. The engine may e.g. be used as the main engine in an ocean going vessel or as a stationary engine for operating a generator in a power station. The total output of the engine may, for example, range from 5,000 to 110,000 kW.

The engine is a diesel (self-igniting) engine of the two-stroke uniflow type with scavenge ports at the lower region of the cylinders 1 and an exhaust valve 4 at the top of the cylinders 1. Thus the flow in the combustion chamber is always from the bottom to the top and thus the engine is of the so called uniflow type. The scavenging air is passed from the scavenging air receiver 2 to the scavenging air ports (not shown) of the individual cylinders 1. A reciprocating piston 41 in the cylinder 1 compresses the charging air, fuel is injected, combustion follows and exhaust gas is generated. When an exhaust valve 4 is opened, the exhaust gas flows through an exhaust duct 35 associated with the cylinder 1 concerned into the exhaust gas receiver 3 and onwards through a first exhaust conduit 18 to a turbine 6 of the turbocharger 5, from which the exhaust gas flows away through a second exhaust conduit 7. Through a shaft 8, the turbine 6 drives a compressor 9 supplied via an air inlet 10. The compressor 9 delivers pressurized charging air to a charging air conduit 11 leading to the charging air receiver 2.

The scavenging air in the conduit 11 passes through an intercooler 12 for cooling the charging air.

The cooled charging air passes via an auxiliary blower 16 driven by an electric motor 17 that pressurizes the charging air flow in low or partial load conditions to the charging air receiver 2. At higher loads the turbocharger compressor 9 delivers sufficient compressed scavenging air and then the auxiliary blower 16 is bypassed via a non-return valve 15.

The cylinders are formed in a cylinder liner 50. The cylinder liners 50 are carried by a cylinder frame 46 that is supported by the engine frame 45. A cylinder cover 52 is placed on top of the cylinder liner 50, so that a combustion chamber is defined in the cylinder between the piston 41 and the cylinder cover 52.

Fig. 6 shows the central opening in the cylinder cover for the exhaust valve with the seat 57 of the exhaust valve .

The cylinder liner has an upper surface 51 that faces the bottom surface 53 of the cylinder cover 52 when the latter is installed on the cylinder liner 50.

The cylinder cover 52 is pressed onto the top of the cylinder liner 50 by cylinder cover studs (not shown) that extend through bores 58 in the cylinder cover 52.

In an example embodiment a sealing ring 60 is placed in a recess 70. The recess 7 0 can be formed in the downwardly facing surface 53 of the cylinder cover 52 or in of the upwardly facing top surface 51 of the cylinder liner. In the shown example embodiment the recess 70 is arranged in the top surface 51 of the cylinder liner 50.

The sealing ring 60 is an annular ring of soft metal, such as e.g. soft iron. The sealing ring 60 has a width w (between its radially inner side surface 63 and its radially outer side surface 64) and a height h (between its top surface 61 and its bottom surface 62).

The recess 7 0 has a width W (between its radially inner side surface 72 and its radially outer side surface 73) that is substantially identical to the width w of the sealing ring 60.

The recess has a depth D that is less than the height h of the sealing ring 60, so that the sealing ring will protrude from the recess 70 when it has been placed in the recess 70.

The recess 70 is delimited by a bottom surface 71, a radially inner side surface 72 and a radially outer side surface 73. The radially inner side surface 72 is formed by a radially inner annular elevation 76. The radially outer side surface 73 is formed by a radially outer annular elevation 78. The bottom surface 71 is in an example embodiment a planar surface.

In this example embodiment the radially inner side surface 72 and the radially outer side surface 73 taper so the upper edge of the two side surfaces 72,73 is closer spaced than the lower edge of the two side surfaces. Thus, the recess 70 forms an annular groove similar to a groove of a dovetail joint.

In this example embodiment the sealing ring 60 has a convex top surface 61 and a concave bottom surface 62 before the sealing ring 60 is pressed flat between the cylinder liner 50 and the cylinder cover 52. The sealing ring 60 has a radially inner side surface 63 and a radially outer side surface 64 that connect the top surface 61 to the bottom surface 62. The side surfaces 63, 64 are substantially parallel before the sealing ring 60 is pressed flat between the cylinder liner 50 and the cylinder cover 52. Figs. 9 and 11 show the sealing ring 60 before it has been pressed flat, i.e. when it is in its curved initial configuration before being deformed.

When the sealing ring 60 is installed in the recess 70 and pressed flat between the between the cylinder liner 50 and the cylinder cover 52 the sealing ring 60 deforms so that the previously parallel side surfaces 63,64 taper after the deformation with the upper edge of the two side surfaces 63,64 being closer spaced than the lower edge of the two side surfaces 63, 64, as shown in Fig. 12. The tapering side surfaces 63, 64 of the sealing ring 60 fit exactly between the tapering side surfaces 72,73 of the recess 70 and thereby, the sealing ring 60 is geometrically locked to the cylinder liner 50 by an annular dovetail joint. The deformation of the sealing ring 60 when it is pressed flat is plastic, so the geometric lock is permanent, also when the pressure of the cylinder cover 52 is removed, e.g. during lift of the cylinder cover 52.

The geometric lock ensures that the sealing ring 60 is properly secured to the cylinder liner 50 and stays in the recess if a cylinder cover lift should occur. Thus, neither the sealing ring 60 nor any part of it will be shot into the engine room. Further, the sealing ring 60 will normally not be damaged by a cylinder cover lift event and thus there will be no sequential damage to the surface of the cylinder cover 52 and of the cylinder liner 50.

Figs. 13 to 15 illustrate an arrangement to make it possible to remove the sealing ring 60 from the recess 70 after it has deformed and assumed its geometric lock. The arrangement may include one or more slots 7 9 in the radially outer elevation 78 for providing access for a tool like a crowbar to pry the sealing ring 60 up and out of the recess 70.

In addition or as an alternative arrangement to make it possible to remove a sealing ring 60 from the recess 70 a threaded bore 81 through the sealing ring 60 opening to the bottom surface 71 can be provided for allowing the sealing ring 60 to be pushed up and out of the recess 70 by screwing a bolt into the threaded bore 81, the tip of the bolt engaging the bottom surface 71 and forcing the sealing ring 60 out of the recess 70 by further rotation of the bolt.

In the embodiments above the annular recess 70 is provided in the top of the cylinder liner 50. It is though clear to a skilled person that the recess 70 for receiving the sealing ring can instead be provided in the cylinder cover 52.

Further, the sealing ring 60 can be secured in the annular recess 70 by other suitable means than an annular dovetail joint, such as e.g. other forms of geometric locks, bolts through the sealing ring that engage threaded bores in the bottom surface 71, or a press fit connection.

The term "comprising" as used in the claims does not exclude other elements or steps. The term "a" or "an" as used in the claims does not exclude a plurality. The single processor or other unit may fulfill the functions of several means recited in the claims.

The reference signs used in the claims shall not be construed as limiting the scope.

Although the present invention has been described in detail for purpose of illustration, it is understood that such detail is solely for that purpose, and variations can be made therein by those skilled in the art without departing from the scope of the invention.

Claims

1. Stor, turboladet, totakts, selvtændende forbrændingsmotor, hvilken motor omfatter: i det mindste en cylinderforing (50) med et cylinderdæksel (52) oven på den i det mindste ene cylinderforing, hvor cylinderdækslet (52) har en første overflade (53), der vender mod den øverste del af cylinderforingen (50), og hvor den øverste del af cylinderforingen har en anden overflade (51), der vender mod cylinderdækslet (52), en tætningsring (60) mellem den første overflade (53) og den anden overflade (51), hvilken tætningsring (60) har en højde (h) og en bredde (w) mellem den radialt indvendige side af overfladen (63) på tætningsringen (60) og den radialt udvendige side af overfladen (64) på tætningsringen (60), kendetegnet ved, at den første overflade (53) eller den anden overflade (51) er forsynet med en ringformet udsparing (70) med en dybde (d) og en bredde (W), hvor bredden (W) svarer til bredden (w) af tætningsringen (60), hvor dybden (d) er mindre end højden (h), og hvor tætningsringen (60) er optaget delvist i den ringformede udsparing (70), idet en del af højden (h) af tætningsringen (60) rager frem fra udsparingen (70), og idet tætningsringen (60) er fastgjort til udsparingen (70) .A large, turbocharged, two-stroke, self-igniting internal combustion engine, comprising: at least one cylinder liner (50) with a cylinder cover (52) on top of the at least one cylinder liner, with the cylinder cover (52) having a first surface (53) facing the upper part of the cylinder liner (50) and the upper part of the cylinder liner having a second surface (51) facing the cylinder cover (52), a sealing ring (60) between the first surface (53) and the a second surface (51), the sealing ring (60) having a height (h) and a width (w) between the radially inner side of the surface (63) of the sealing ring (60) and the radially outer side of the surface (64) of the sealing ring (60), characterized in that the first surface (53) or the second surface (51) is provided with an annular recess (70) having a depth (d) and a width (W), the width (W) corresponding to the width (w) of the sealing ring (60), the depth (d) being less than the height (h), and or the sealing ring (60) is partially accommodated in the annular recess (70), a portion of the height (h) of the sealing ring (60) protruding from the recess (70) and the sealing ring (60) being secured to the recess (70) .

2. Motor ifølge krav 1, ved hvilken udsparingen er udformet mellem to koncentriske ringformede forhøjninger (76, 78) på den første overflade (53) eller på den anden overflade (51).The engine of claim 1, wherein the recess is formed between two concentric annular elevations (76, 78) on the first surface (53) or on the second surface (51).

3. Motor ifølge krav 1 eller 2, ved hvilken tætningsringen (60) er fastgjort til udsparingen (70) ved hjælp af en geometrisk lås mellem tætningsringen (60) og udsparingen (70).The motor of claim 1 or 2, wherein the sealing ring (60) is secured to the recess (70) by a geometric lock between the sealing ring (60) and the recess (70).

4. Motor ifølge krav 3, ved hvilken udsparingen (70) indeholder en flad bundflade (71) og sideflader (72, 73), som løber ud i en spids, og som bliver bredere hen mod bundfladen (71), og ved hvilken tætningsringen (60) er forsynet med en overside (61) og en modsatliggende bundflade (62), der er forbundet ved hjælp af sideflader (63, 64) som løber ud i en spids, og som bliver bredere hen mod bundfladen (62), og ved hvilken tætningsringen (60) er placeret i den ringformede udsparing (70) med sin bundflade (73) vendende mod bundfladen (71) på den ringformede udsparing (70).The motor of claim 3, wherein the recess (70) includes a flat bottom surface (71) and side surfaces (72, 73) which extend into a tip and which extend wider toward the bottom surface (71), and wherein the sealing ring (60) is provided with an upper surface (61) and an opposing bottom surface (62) which is connected by a side surface (63, 64) extending into a tip and which becomes wider towards the bottom surface (62), and at which the sealing ring (60) is located in the annular recess (70) with its bottom surface (73) facing the bottom surface (71) of the annular recess (70).

5. Motor ifølge krav 4, ved hvilken tætningsringen (60) er bueformet, således at dens overside (61) er konveks, og dens bundflade (62) er konkav, og dens sideflader (63, 64) strækker sig i det væsentlige parallelt, når tætningsringen (60) indsættes i den ringformede udsparing (70) .The motor of claim 4, wherein the sealing ring (60) is arcuate so that its upper face (61) is convex and its bottom surface (62) is concave and its side faces (63, 64) extend substantially parallel. when the sealing ring (60) is inserted into the annular recess (70).

6. Motor ifølge krav 5, ved hvilken tætningsringen (60) fladtrykkes, når cylinderdækslet (52) monteres på cylinderforingen (50), hvorved sidefladerne (63, 64) på tætningsringen (60) antager en tilspidset udformning, der svarer til den tilspidsede udformning af sidevæggene (72, 73) på den ringformede udsparing (70), hvorved tætningsringen (60) låses geometrisk sammen med den ringformede udsparing (70).The engine of claim 5, wherein the sealing ring (60) is flattened when the cylinder cover (52) is mounted on the cylinder liner (50), whereby the side faces (63, 64) of the sealing ring (60) assume a tapered configuration corresponding to the tapered configuration. of the side walls (72, 73) of the annular recess (70), thereby locking the sealing ring (60) geometrically with the annular recess (70).

7. Motor ifølge krav 5 eller 6, ved hvilken tætningsringen (60) og udsparingen (70) udformer en ringformet svalehalesamling.The motor of claim 5 or 6, wherein the sealing ring (60) and the recess (70) form an annular dovetail assembly.

8. Motor ifølge krav 1 eller 2, ved hvilken tætningsringen (60) er fastgjort til den ringformede udsparing (70) ved hjælp af en prespasningsforbindelse.The motor according to claim 1 or 2, wherein the sealing ring (60) is secured to the annular recess (70) by means of a press fit connection.

9. Motor ifølge krav 1 eller 2, ved hvilken tætningsringen (60) er fastgjort til den ringformede udsparing (70) ved hjælp af fastgørelsesmidler som for eksempel bolte.The motor of claim 1 or 2, wherein the sealing ring (60) is secured to the annular recess (70) by means of fasteners such as bolts.

10. Tætningsring af blødt metal (60) til tætning mellem en cylinderforing (50) og et cylinderdæksel (52) på en stor, turboladet, selvtændende, totakts forbrændingsmotor, hvilken tætningsring (60) indeholder en overside (61) og en bundflade (62), der er forbundet ved hjælp af sideflader (63, 64), kendetegnet ved, at oversiden (61) er konveks, at bundfladen er (62) er konkav, og at sidefladerne (63, 64) i det væsentlige er parallelle.A soft metal sealing ring (60) for sealing between a cylinder liner (50) and a cylinder cover (52) of a large, turbocharged, self-igniting, two-stroke internal combustion engine, which sealing ring (60) includes an upper side (61) and a bottom surface (62). ), which are connected by side surfaces (63, 64), characterized in that the top surface (61) is convex, that the bottom surface (62) is concave and that the side surfaces (63, 64) are substantially parallel.

11. Tætningsring af blødt metal (60) ifølge krav 10, hvilken tætningsring af blødt metal (60) er udformet til at blive fladtrykket, når den monteres mellem cylinderforingen (50) og cylinderdækslet (52), idet oversiden (61) og bundfladen (62) antager en i det væsentlige flad form, og sidefladerne (63, 64) har en tilspidset udformning, der bliver bredere hen mod bundfladen (62).A soft metal sealing ring (60) according to claim 10, said soft metal sealing ring (60) being designed to be flat-pressed when mounted between the cylinder liner (50) and the cylinder cover (52), the upper side (61) and the bottom surface ( 62) assumes a substantially flat shape, and the side surfaces (63, 64) have a tapered configuration which becomes wider towards the bottom surface (62).