GB2099075A

GB2099075A - A cylinder block for an internal combustion engine

Info

Publication number: GB2099075A
Application number: GB8205899A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-02-27
Filing date: 1982-03-01
Publication date: 1982-12-01
Also published as: IT8219566A0; KR890000454Y1; DE3107461C2; GB2099075B; JPS57206749A; DE3107461A1; FR2500907A1; KR830009360A; IT1149598B; JPS6340271B2; MY8700791A

Abstract

The cylinder block 1 has at least one cylinder (3) connected to the inside wall of the block by means of an annular flange (8) having anchorages (16) for receiving fastening means (17), e.g. bolts, holding a cylinder head (4) on the block. The flange (8) has at least one passage (13, 14, 15) for cooling medium for cooling the cylinder and is spaced from the cylinder head (4) so that the portion (9) of the cylinder therebetween is sufficiently resiliently-flexible to prevent, during use, permanent deformation thereof. If the cylinder- head end of the cylinder (3) and block (10) are ground flat there is no need for a cylinder-head gasket. The cooling medium may be oil or diesel fuel. <IMAGE>

Description

SPECIFICATION A cylinder block for an internal combustion engine This invention relates to a cylinder block for a reciprocating internal combustion engine, particularly a Diesel engine.

It is known in the design of reciprocating internal combustion engines, such as a Diesel engine or an Otto-cycle engine, to provide a cylinder block and to arrange at least one cylinder as well as slider crank mechanism in the cylinder block. The cylinder block which, depending on the size and construction of the internal combustion engine, may be an aluminium, grey iron or steel casting, are constructed with an appropriate number of cylinders and with parts covering the top and bottom of the block, such as the oil sump and the cylinder head.

Such a cylinder block is provided with supports to mount the crankshaft bearing. Pipes are also attached to it to serve for the supply and removal from the cylinder block of a coolant for conditioning medium. In the region of the interface between the cylinder head and cylinder and cylinder block on one side and between the cylinder block and the oil sump on the other side, gaskets are provided for sealing the cylinder block against the cylinder head and oil sump respectively.

Experience with internal combustion engines of this type has shown that it is in particular the gasket between the cylinder block and the cylinder head which is highly vulnerable in such an engine and that this gasket tends to cause frequent breakdowns in internal combustion engines.

Added to this is the fact that, in existing internal combustion engines, constraints are often set up, in particular between the cylinder and the cylinder head, because the heating of the cylinder in the region of the combustion zone of the slider crank mechanism is very intense and existing cooling systems often cannot be made large enough to cope with this enormous amount of heat.

In order to overcome these deficiencies, engines have been constructed as so-called "heattight" engines, thermal tightness being ensured by providing thermal insulation around the combustion chamber. Such insulation either takes the form of barriers or physical design features, in particular, of the slider crank mechanism and the cylinder head.

An existing internal combustion engine of the so-called heat-tight type features a piston system allied to each working cylinder, the piston system essentially consisting of a piston formed by two units of which the one unit provides the sealing functions and the other unit the guiding function for the piston in the cylinder. The guiding unit, which consists of a ring carrier, a shell supporting the latter and a foot which enters into the shell, is formed inside the shell with a preferable rotationsymmetrical combustion chamber which is thermally insulated against both the ring carrier and the foot of the piston. The thermal insulation of the combustion chamber may taken the form either of a restriction in the material transition from the shell to the ring carrier and/or shell to the foot and/or of a special material filling having a low heat conductivity.As a result of this design and the arrangement of the combustion chamber, the heat produced by the combustion of air and fuel constituents is effectively retained in the combustion chamber and can be passed through the restrictions to the ring carrier or foot of the piston so that, in particular, the piston rings on the ring carrier are protected from excessive overheating and the ring carrier itself with its socalled slides on the cylinder wall while forming an effective seal. The other unit guiding the piston in the cylinder is largely relieved of the heat of combustion and formed so as to transmit only normal forces and dissipate any remaining heat of combustion to be removed through the foot of the piston and a coolant sprayed against the latter (cf.

German Patent Specification 2 545 588).

An object of the present invention is to provide a cylinder block in which constraint between the cylinder and its block and the cylinder head are effectively reduced, and deformations, in particular of the cylinders due to thermal distortion and/or the effect of normal forces of the moving parts on the cylinder and, thereby, on the cylinder block can be resiliently absorbed, in particular by the cylinder.

The invention provides a cylinder block having a cylinder-head and containing at least one cylinder connected to the cylinder block by means of an annular flange having fastening-receiving means for receiving fastening means for fixing a cylinder head to the cylinder block, the annular flange having at least one passage for cooling medium for cooling the outside of the cylinder, the annular flange being spaced from the cylinder-head end so that the portion of the cylinder therebetween is sufficiently, resiliently-flexible to prevent, during use, permanent deformation thereof.

Thus, in as much as the cylinders are subjected to movements due to the effect of the combustion gas heat and the forces of the moving parts, they can readily adjust to these changes. As a result of the flexible properties of the cylinders, permanent deformation of the cylinders is avoided so that friction losses between the piston and the cylinder running surfaces can be minimized.

Another advantage of these features can be seen in the fact that the clamping means for fixing the cylinder head to the cylinder block are applied at a level where thermal stresses are to a large extent avoided. In consequence of this, it is possible for these clamping means to be made, in particular, with a lower thermal strength and to move easily in their anchorages, even after several hours of operation of the internal combustion engine because at the level they are not livable to seize in their anchorages due to thermal effects.

An embodiment of the invention will now be described with reference to the accompanying drawing, in which: Fig. 1 is a section through a cylinder block taken along the line I-I of Fig. 2 without the cylinder head and oil sump being shown in full, and Fig. 2 is a plan view of a cylinder block having three cylinders and with the cylinder head removed.

In the drawing, a cylinder block 1 for a reciprocating internal combustion engine such as a Diesel engine, comprises essentially an outer shell 2 and at least one cylinder 3 (here three) arranged therein. The shell 2 has at one end at ..least one cylinder head 4 closing the cylinders 3, at the other end an oil sump 5 as well as lateral and end walls enclosing the cylinders 3. A slider crank mechanism which (not shown) is provided in the cylinder block and this comprises essentially a piston moving axially in each cylinder 3 and a connecting rod linking each piston to a crank and crankshaft. The crankshaft is housed in a crank space 6 of the cylinder block 1 and, in particular, the end walls of the cylinder block are provided with recesses 7 to accommodate the bearings of the crankshaft.

So that the cylinder 3, particularly its section exposed to the heat of combustion, has a flexibility which will prevent permanent deformation, the cylinder is connected through the intermediary of a flame plate 8 to the cylinder block 1. The flange plate 8 is an integral part of the cylinder block, i.e.

is contiguous with the shell and the cylinder. The flange plate 8 is attached to the outer surface of the cylinder 3 and the inner surface of the surrounding well portion of the cylinder block 1 and proportioned so that, while supporting the cylinder adequately against the outer wall of the block, flexible movement of the cylinder sections 9, 10 which extend upwards and downwards is virtually unaffected.

Spaces 11, 12 are provided between the outer surface of the cylinder 3 and the inner surface of the shell 2 and are separated from each other only by the flange plate 8. The spaces 11, 12, which prevent the transmission of the heat of combustion from the cylinder 3 to the cylinder block 1, can be provided with a temperature controlling medium. This may be fed into the space 11 at the level of the cylinder section 9, which is more intensely exposed to the heat of combustion.Such medium, e.g. oil or Diesel fuel, may be fed in by a hole 1 3 in the flange plate 8 and communicating via a branch passage 1 4 with the space 11. For discharge of the medium from the space 11, a distance passage 1 5 may be provided in the opposite side of the flange plate 8 connecting the space 11 to the space 12 and hence to the crankspace 6. The medium may alternatively or additionally be discharged from the space 11 through a discharge passage (not shown) in the cylinder head 4.

The cylinder head 4 is fixed to the cylinder block 1 by means of several anchorages and/or fastening means 16, which arranged concentrically about the longitudinal centreline X of the cylinder 3 at the flange plate 8, and clamping means 17 e.g. in the form of bolts or screws inserted therein from the cylinder head.

The clamping means 1 7 may extend through the space 11 above the flange plate 8 so that they are exposed to the fiow of conditioning medium. The surfaces of the cylinder 3 and the cylinder block 1 adjacent the cylinder head 4 are preferably ground flat and connected to the cylinder head in a forcelocking manner so that a gasket between these surfaces and the cylinder head can be dispensed with.

Any leakage which may, for instance, occur from the cylinder 3 via the surface 1 8 to the outside is trapped in the space 11 provided between the cylinder 3 and the inner wall of the cylinder block 1 and is removed by the continuous flow of conditioning medium. Even soot particles or other particles which might penetrate past this surface 1 8 into the space 11 would not affect combustion and, consequently, the internal combustion engine, since they can be retained and separated out by a filter (not shown) arranged in the conditioning medium circuit.

To facilitate manufacture of the cylinder block 1, the spaces 11, 12 are made of V-section seen in the longitudinal centre-section of the cylinder block, the wider end of the V being at the cylinder head 4 or the crankspace 6. This shape ensures that the mould parts after casting the cylinder block 1 can be very conveniently pulled out whereby the mould is also greatly simplified.

If ventilation is desired, in particular, where, several cylinders 3 are used in one cylinder block 1, webs 19 separating the cylinders from each other may be provided with openings 20 through which the ventilation streams may blow to and fro.

The cylinder block 1 shown has three cylinders 3. It is, of course, possible to provide several cylinders 3 in line in the direction of the crankshaft and to construct all these cylinders similar to the embodiment shown in Figs. 1 and 2. A preferred embodiment of such a cylinder block 1 may, for instance, be constructed with the three cylinders 3, which will be sufficient in most cases to produce the propulsive power of the internal combustion engine in conjunction with its drive parts and control means. However more than three such cylinders or only one such cylinder may be used.

In the embodiment shown in Figure 2, the cylinders are connected to each other in the longitudinal direction of the casing block 1. This does not rule out an arrangement where the walls of the cylinders 3 are separate and, consequently, an annular shape is maintained and the spaces 11 and 12 extending therearound are also annular shaped around the cylinders 3. Furthermore, it does not rule out an arrangement where, for instance, one space 11 is annular shaped and the other space 12 as shown in Fig. 2 is formed with its annular shape interrupted by the walls of adjoining cylinders 3 (see broken line in Fig. 1).

Claims

1. A cylinder block having a cylinder-head end and containing at least one cylinder connected to the cylinder block by means of an annular flange having fastening-receiving means for receiving fastening means for fixing a cylinder head to the cylinder block, the annular flange having at least one passage for cooling medium for cooling the outside of the cylinder, the annular flange being spaced from the cylinder-head end so that that portion of the cylinder therebetween is sufficiently resiliently-flexible to prevent, during use, permanent deformation thereof.

2. A cylinder block as claimed in Claim 1, wherein the space between the annular flange and the cylinder-head end is annular shaped is concentric with a longitudinal axis of the cylinder and is terminated by the annular flange.

3. A cylinder block as claimed in Claim 2, wherein the space extends from the cylinder-head end only as far as the cylinder is exposed, in use, to the heat of combustion of gases of the cylinderhead end.

4. A cylinder block as claimed in any one of the preceding claims, wherein the end surfaces of the cylinder and the cylinder block at the cylinderblock end are ground planar so that, in use, these surfaces contact the cylinder head flatly without the interposition of a gasket.

5. A cylinder block as claimed in any one of the preceding claims, wherein the annular flange has at least one inlet passage for supply the cooling medium this passage being provided with a branch line communicating with the space.

6. A cylinder block as claimed in Claim 5, wherein the annular flange is also provided with at least one discharge passage extending from the space to a crank space of the block.

7. A cylinder block as claimed in any one of the preceding claims, wherein the space between the outer surface of the cylinder and the inner surface of the block is formed with a V-shaped configuration in the longitudinal direction of the cylinder with the V opening towards the cylinderhead end.

8. A cylinder block as claimed in any one of the preceding claims, wherein there is a further space between the outer surface of the cylinder and the inner surface of the block, the further space extending from the annular flange and having a Vshaped configuration in the longitudinal direction of the cylinder with the V opening out towards a crank space of the block.

9. A cylinder block as claimed in any one of the preceding claims and having at least two cylinders arranged in tandem, the cylinders having a separating partition therebetween, the or each partition, at the end of the cylinder extending to the crank space, having an opening for ventilation of the crank space and/or adjacent cylinder space.

10. A cylinder block substantially as herein described with reference to the accompanying drawing.

11. An internal combustion engine having a cylinder block as claimed in any one of the preceding claims.