GB2158510A

GB2158510A - An internal combustion engine with a cylinder liner

Info

Publication number: GB2158510A
Application number: GB08510858A
Authority: GB
Inventors: Hans-Jurgen Schacht
Original assignee: Krupp Mak Maschinenbau GmbH
Current assignee: Caterpillar Motoren GmbH and Co KG
Priority date: 1984-05-11
Filing date: 1985-04-29
Publication date: 1985-11-13
Also published as: FR2564146A1; FR2564146B1; GB8510858D0; DE3417515C1; GB2158510B; JPS60240851A

Abstract

In order to prevent the damaging effect of heat and pressure from a combustion chamber (21) on a cylinder liner 14 an intermediate member or fire ring (20) which may be fluid cooled, is disposed around the combustion chamber (21) between a support collar (15) on the liner 14 and the cylinder head (13). <IMAGE>

Description

SPECIFICATION Internal combustion engine with a cylinder liner sleeve The invention relates to an internal combustion engine with an improved cylinder liner sleeve arrangement.

In the simplest form of an engine of this type, a cylinder liner sleeve is sealingly mounted in a cylinder block to protrude above the block to define a support collar, the support collar being of a larger outside diameter than the portion of the sleeve received in the cylinder block. A cylinder head is mounted on the top of the support collar. For increased engine size and power, the diameter of the collar needs to be increased to withstand increased combustion pressures, but this has the disadvantage that the cooling of the engine is unfavourably impaired due to an increased path length along which the combustion heat must flow in order to be dissipated.

W. German Patent Specification 425 080 discloses an internal combustion engine with cylinder liner sleeves with a support collar which has a groove with a cooling pipe embedded in an alloy with good conducting properties. However, the resistance of the collar to shearing effects caused by the ignition forces is considerably weakened by the cooling arrangement.

W. German Offenlegungsschrift 27 25 059 discloses an internal combustion engine, in which the cylinder liner is tapered at the end adjacent to the cylinder head and is surrounded at this location by a support ring forming the support collar, which ring is designed to be connected to the sleeve by soldering, welding or spring plates. As, however, absolute operational reliability is required particularly in the case of large ships' engines, a connection of this type between the sleeve and the collar may be considered to be a weak point in the case of high stresses.

The object of the invention is to provide a construction which reduces the harmful effect of combustion pressure and heat from the combustion chamber on the cylinder liner sleeve in the cylinder block.

According to the invention there is provided an internal combustion engine including a cylinder block, a piston slidably mounted in a cylinder liner sleeve received in the cylinder block, a cylinder head, a combustion chamber formed between the head and the piston, and a separate member between the liner sleeve and'the head, said member bounding the periphery of the combustion chamber.

This separate member, preferably in the form of a "fire ring" as discussed in the following description, assumes the function of the cylinder liner in the region of the combustion chamber. The waste heat from the heat of combustion consequently scarcely reaches the liner but is taken up by the fluid-cooled wall of the fire ring. The heat expansion of the liner is thereby considerably reduced, the thermal stress on lubricant oil is reduced and the travel conditions for rings on the piston are considerably improved.

As will be more apparent from the following description of embodiments of the invention the result of the insertion of the fire ring between the cylinder head and the liner the upper edge of the liner and of the support collar is disposed considerably deeper with respect to the piston and a first piston ring which limits the pressure, so that the ignition pressure need no longer have an effect on the thin liner sleeve, but is essentially taken up by the fire ring and the support collar of the liner. All the stresses and expansions caused by the effect of the ignition pressure in the case of conventional constructions are considerably reduced.

The reduction of the heat passing into the jacket surface of the travel sleeve enables, in the embodiment of the invention, the travel sleeve to be supported below the support collar in the cylinder block which was problematic in the case of prior devices as a result of the long heat path.

In addition, it is possible, as a result of the lower heat stress to seal the above-mentioned area of the guide in the foot with elastomers. Stresses on the guide at its bearing location by displacement, water pressure or corrosion are consequently considerably reduced.

In a further embodiment of the invention the fire ring is embodied in such a way that it grips the upper edge of the support collar of the liner. If materials having a suitable tensile strength are seiected, the fire ring which is kept relatively cool by the fluid cooling may consequently provide a radial uppersuppoitforthe liner. Travel of the piston or the piston rings does not have to be taken into account in the selection of materials for the fire ring.

As a result of the support, which may even be doubled if necessary, the liner may be kept substantially cylindrical in all operating conditions.

In addition the fire ring, as a result of its resilient height, may simultaneously improve the distribution of the forces produced by screws used to locate the cylinder head for the sealing of the combustion chamber. The connection line from the upper area of the cylinder clock to the cylinder head may advantageously be tapped for the purposes of cooling the fire ring.

Cooling fluid may also be fully guided by the ring.

This may have a single channel, as a result of which the fluid inlet and outlet are disposed on that side of the ring, or may be provided with a plurality of grooves.

The fire ring may also be separately cooled and the quantity of fluid may be adjusted as a function of the engine load, which advantageously prevents corrosion effects due to too little lubricant oil or overloading of the lubricant oil by wall temperatures which are too high.

Finally it may be advantageous, for improved use of the heat, to cool the fire ring in a cooling circuit which is separate from the engine cooling system, as the cooling fluid may then be used for example to preheat the feed water.

The invention is described in greater detail in the following description of two embodiments shown in diagrammatic form in the attached drawings, in which: Fig. 1 is a partial section through an engine of conventional construction, with a cylinder liner having a high collar, Fig. 2 is a partial section through an engine of the invention with a fire ring and a shortened liner, and Fig. 3 is a partial section through a further embodiment of an engine of the invention with a fire ring supporting the support collar of the liner.

In Fig. 1, a cylinder block is designated by 1, a cylinder head by 2 and a cylinder head screw by 3. A cylinder liner sleeve 4 is embedded in the engine block 1, with a support collar 5 and cylinder jacket portion 6 of narrower outside diameter than the support collar 5, in such a way that between the jacket portion 6 and the block 1, there is formed a chamber 7 for the circulation of the cooling fluid. A piston 8 with a piston rings 9 moves within the jacket portion 6 of the sleeve 4 in a known manner, such that in the upper dead centre of the piston 8 a combustion chamber 10 is formed between the piston the support collar 5 and the cylinder head 2.

Arrows 11 show how in this conventional construction of a combustion chamber 10 the heat of combustion is transferred along a rather long path in the cooling fluid via the support collar 5 into the chamber 7. It is evident that this unfavourable heat discharge may easily lead to heat overloading of the lubricant oil as a result of coking and excess wear of the combustion chamber and the travel surfaces. Any attempt to shorten the heat flow paths by shortening the support collar however results in a weakening of the construction particularly as a result of a reduction in the resistance to shearing.

Fig. 2 shows a cylinder block 12 and a cylinder head 13 which covers the cylinder. A piston sleeve 14 with a support collar 15 and a cylinder jacket portion 16 is embedded in the cylinder block 12 in such a waythata cooling fluid guide 17 is formed between the jacket portion 16 and the cylinder block 12.

Within the sleeve 14 there moves a piston 18 with rings 19 which in Fig. 2 is disposed approximately in its upper dead centre position. It should be noted that in this position the portion of the piston 18 lying above the piston rings 19 projects over the upper edge of the support collar 15 of the sleeve 14.

In accordance with the invention, an intermediate member 20 which may be fluid-cooled and which forms the cylinder wall above the piston rings 19, also called a "fire ring", embraces the combustion chamber 21 between the support collar 15 and the cylinder cover 13 in an annular manner. The fire ring 20 therefore takes over with respect to its axial height the function of the jacket surface of the combustion chamber wall in place of the sleeve. Fig.

2 also shows how the cylinder block 12 is connected with the fire ring 20 for cooling, via a cooling line 22, the direction of flow of cooling fluid being shown by arrows.

A further embodiment of an internal combustion engine with a cylinder head 23, a sleeve 24 and a fire ring 25 therebetween is shown in Fig. 3. In this case the cooling of the fire ring 25 is connected through a cooling line 26 with the cylinder head 23, the direction of flow of the cooling fluid also being shown by arrows. As the fire ring 25 may be kept, by means of the fluid cooling, at fairly low temperatures, by selecting suitable materials with high tensile strength an upper radial support 27 of the sleeve 24 is possible.

In addition, as a result of the lower introduction of heat into the sleeve 24, the latter may be provided below its support collar with a further support 28 in the frame and the support may be sealed with a rubber seal 29.

Claims

1.An internal combustion engine including a cylinder block, a piston slidably mounted in a cylinder liner sleeve received in the cylinder block, a cylinder head, a combustion chamber formed between the head and the piston, and a separate member between the liner sleeve and the head, said member bounding the periphery of the combustion chamber.

2. An internal combustion engine according to claim 1 wherein said separate member includes cooling channel means for cooling fluid.

3. An internal combustion engine according to claim 2 wherein said cooling channel means is connected to a cooling channel in said cylinder block or said cylinder head.

4. An internal combustion engine according to any preceding claim wherein said separate member comprises a ring with an annular cooling channel therein.

5. An internal combustion engine according to any preceding claim wherein said sleeve and said separate member have cooperating lipped peripheries to locate said member on the sleeve.

6. An internal combustion engine according to any preceding claim wherein said cylinder head and said separate member include cooperating lipped peripheries to locate the head on the separate member.

7. An internal combustion engine according to any preceding claim including a resiliently deformable annular seal, sealing said liner in said block.

8. An internal combustion engine substantially as herein described with reference to Figure 2 of the accompanying drawings.

9. An internal combustion engine substantially as herein described with reference to Figure 3 of the accompanying drawings.

10. An internal combustion engine with a cylinder head and piston travel sleeves with a support collar in the vicinity of the cylinder head characterised in that between the support collar and the cylinder head there is disposed an intermediate member which may be fluid-cooled and which embraces the combustion chamber in an annular manner, and forms the cylinder wall of the cylinder jacket portion above the area of the piston ring.

11. An internal combustion engine as claimed in claim 10 characterised in that the intermediate member forms an upper radial support for the travel sleeve collar