SE538136C2 - Arrangement for cylinder head gasket in an internal combustion engine - Google Patents

Abstract

A cylinder head gasket (23) is arranged between a cylinder block (4) and a cylinder head (10) in an internal combustion engine (3). The cylinder head gasket (23) provides a gas and liquid impermeable seal between said parts and is designed to be compressively sealing by pressing the cylinder head (10) against the cylinder block (4) with screws (25) extending through the cylinder head (10) into screw holes (26). ) in the cylinder block (4). The tightening screws (25) are tightened, tensile stresses arise around the screw holes (26) in the cylinder block (4). These tensile stresses are superimposed with the varying loads caused by the operation of the motor (3), which can lead to an increased risk of breakage and cracking. The cylinder head gasket (23) has a varying thickness, which reduces the tensile stresses. Fig. 1

Description

The present invention relates to an arrangement in an internal combustion engine according to the preamble of claim 1.

BACKGROUND AND CHANNEL TECHNOLOGY Internal combustion engine type piston engines include one or more pistons when the engine is in operation, each of which is moved back and forth in a cylinder arranged in a cylinder block. The upper cylinders of each cylinder are closed by means of a cylinder head which defines a combustion chamber between the cylinder head and the lower side of the piston. Air is supplied to the combustion chamber and is compressed when the piston is moved towards the cylinder. The head, When the light is hot, the branch to the air and when the piston is near the top layer in the cylinder is ignited and then burns and expands whereby the coil is pressed ncdat. iscylindem. The downward direction of travel of the piston is reversed and the% is converted into a rotation travel in a crankshaft which exerts driving force to a shaft extending from the engine.

A cylinder head gasket is arranged between the upper side of the cylinder block and the underside of the cylinder head. The cylinder head gasket provides a gas and liquid gas chamber between the said parts and is designed to be compressed by the cylinder head being pressed into the cylinder block with screws which tighten. the cylinder head and into the corresponding gangue the slide in the cylinder block. The cylinder head gasket can be made of a metal plate with an even thickness & extra high pressure gasket pressure is obtained immediately around the combustion chamber by compressing the cylinder head gasket against an axial part of the cylinder head protrudes a bit over the upper surface of the cylinder block. It is also UM; eg, by. US 6,113,109 also utilize a cylinder head gasket that is locally thicker in the area immediately around the cylinder to provide improved gas tightness. In this unloading, extra ca-ca-packing pressure is obtained around the combustion nim by compressing the thicker area of the cylinder head gasket against the cylinder block.

In the case of known solutions, a relatively large force of the finial-axis screw connection must be used to compress the cylinder head gasket to a tensile effect, especially when extra inertial gasket pressure is applied in the line immediately around the furnace combustion chamber. When the cylinder head screws are tightened, tensile stresses arise around the screw-free shaft. in the cylinder bio. These tensile stresses are caused by the varying loads caused by engine operation which can lead to large force gaps in the cylinder block and armed increased risk of breakage and cracking, especially around straw in the cylinder block but also during storage of the cylinder liner in the cylinder block.

SUMMARY OF THE INVENTION An object of the present invention is to provide an arrangement in a tofat-bran: flings motor which arrangement reduces the tensile stresses which arise in the cylinder bio when tightening the screw connection. This object is based on the invention of what is set forth in the characterizing part of the claims. Most materials, and in particular casting as the cylinder block are made of speech, have a significantly greater oscillating load at a superimposed compressive stress state than at a superimposed tensile stress list. . Tests have shown that when the cylinder head clamp is made thicker locally, especially at the time of the cylinder block where the probability that cracks will occur is greatest, so the tensile stresses that arise when the head screws are tightened or become phase. compressive. This is very advantageous for the material to be able to withstand fluctuating loads during operation and reduces the risk of cracking occurring. Test how the invention has been shown to be used to repair already cracked cylinders because the compressive pressure spraying condition that arises when the invention is greatly improved. a crack of a certain size can be reassembled, which eliminates the lack of age that otherwise occurs through the crack.

In an advantageous embodiment, the thicker part is annular and opens around the gas sealing arrangement, the thinner part being arranged radially outside the thicker part. The thicker part extends then Over an amrade d.dr Row risk of crime and crack formation occurs and reduces & trig-mom derma risk. 2 538 136 In a further advantageous embodiment, the thicker part is formed around the mounting hall in the cylinder head gasket. following description of an embodiment exemplary of the invention, Brief Description. of the drawing 1 the following are described as exemplary embodiments of the invention with reference to the accompanying drawing: Fig. 1 shows a vehicle with a boat under which an internal combustion engine is arranged. Fig. 2 shows a cross section through the combustion engine shown in Fig. 1.

Fig. 3 shows an enlarged section of the area A in Fig. 2. Figs. 4 show a first embodiment of a cylinder head gasket according to the invention. Fig. 5 shows a second and a third embodiment of a cylinder head gasket according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION The following figures show selected parts of an internal combustion engine comprising one or more pistons each of which is movably mounted in a cylinder in a cylinder block. The cylinders are Fampligen designed as cylinder liners which are mounted in the intended spaces of the cylinder block, which is also described in the following description. Alternatively, the cylinders may be formed directly in the cylinder block. In the following description, cylinder is defined as the space in which a piston is movable, arranged, regardless of whether the cylinder is formed, is formed by an integral part of the cylinder block or is formed by a cylinder liner arranged in the cylinder blot.

Figure 1 shows a heavy vehicle 1 in the form a, s, a truck with a cab 2 under which an internal combustion engine 3, for example a diesel engine, is arranged. At. alternative uses of the internal combustion engine 3 can be arranged in any other vehicle type, e.g. in a car or in a boat or used as a separate unit to power an electricity-producing unit or the like. Fig. 3 538 136 shows a cross-section through the combustion engine 3 shown in Fig. 1. The engine 3 is, for example, a 6-cylinder diesel engine of the row type, but the engine 3 can of course be of a different type and comprise a different number of cylinders. that the idea of invention is lost.

The internal combustion engine 3 comprises a cylinder head 4 in which six cylinders 5 are formed with substantially cylindrical combustion chambers 6, one of which is shown in the figure, and each of which is delimited in the radial direction by a cylinder liner 7 SO1T1 demarcated in the axial direction by a cylinder head 10 and a piston 11, which is strangely arranged for a reciprocating movement. By means of the expansion which takes place during the explosive combustion, it is moved from the cylinder head 10 in the direction of a crankcase shown where the movement of the piston 11 is transferred to a rotational movement in the crankshaft, the Cytinder liner 7 dr of so-called, plug-in type 8, at the top with the cylinder head 10 and at the bottom with an annular bar insert 14 on the cavity cradle at its lower d el. The cylinder liner 7 abuts the bearing assembly 14 with an annular stand 15 on the outside of the cylinder liner 7. Bdransatsen 14 ° eh. the stand 15 abuts against each other over an annular contactor center near the lower vane of the piston 11, i.e. in the area where the downward movement of the piston 11 over & to an upright movement towards the cylinder head 10.

The cylinder head 10 hr on edge of salt formed with inlet and drain channels for supplying tuft to the combustion chamber 6 and for evacuating combustion gases from the combustion chamber 6. Only one channel 16 is shown in figure 2. The cylinder head 10 is also designed with. recess 17 for not shown friends sorn cooperates with not shown, Tentilsken controls the lute supply and for control of the exhaust gas evacuation. In the cylinder head 10, cooling ducts 18, recesses 19 for fuel injectors for supplying fuel to the combustion chamber 6 are formed, as well as 20 for cylindrical head screws 25 for inserting the cylinder head 10 against the cylinder block 4.

Malan. the upper side of the cylinder block 4, and thus the axon cylinder 5, ° eh. the underside of the cylinder head 10 is a cylinder head gasket 23 arranged.d. The cylinder head gasket 23 hr is formed with at least one annular gas sealing arrangement 24 which provides a gas and liquid impermeable tapping between said parts and is designed to be compressed to a tapping effect by pressing the cylinder head 1 against the cylinder block 4 with the cylinder heads extending through the cylinder heads. in the cylinder head 10, through the sliding cylinder head gasket 23 and into the corresponding aisle hall 26 of the cylinder cylinder 4.

In the embodiment shown in Figure 2 is a cylinder head. 10 oeh, a topsheet gasket 23 disposed at each of six combustion mm. 6, but it is of course possible to use a cylinder head 10 or a cylinder head gasket 23 which extends over a number of combustion chambers 6 without losing the idea of invention. The same cylinder head gasket 23 is, in such a case, formed by a number of continuous passages, each of which corresponds to a combustion chamber 6.

From Fig. 3, which shows an enlarged section of the area A according to Fig. 2, it can be seen that the cylinder liner 7, when facing the cylinder head 10 facing away from its radially inner part, has an ice-ring-shaped axially projecting flange 29. The flange 29 the cylinder head gasket 23 arranged radially outside the flange 29, which is arranged around the one-axis axis of the combustion chamber 6, is true to a height which exceeds the protrusion of the projecting flange 29 HO.

The top plate gasket 23 abuts against a stad surface 28 which extends in height at a higher level than the upper surface 33 of the cylinder block 4 in the unloaded layer of the cylinder liner 7, i.e. When the cylinder head 10 is not yet pressed against the cylinder block 4 with the screws 25. This meant that the support surface 28 in the unloaded idge protrudes a bit over the upper surface 33 of the cylinder block 4.

The support surface 28 is formed with an annular projecting portion 30. The center of the delta portion 30 is formed in the bottom surface of the cylinder head 10 according to the corresponding annular recess 31. The two recesses 30, 31 together form a reinforced sealing zone where the cylinder head gasket 23 is allowed to deform when the screws 25 for filling the annular recess 31 thereby provide an effective gas-free liquid and non-greasy coating.

The cylindrical liner 7 is formed at its cylindrical outer part at its cylindrical outer part by an annular recess 32 with a lower surface which extends at a height at a level of the city surface 28 and at substantially the same level as that of the cylinder block. 4 upper • 538 136 the unloaded position of the cylinder liner 7 for the radius of the support surface 28 is limited to the extent of the support surface 28. After disassembly of the cylinder head 10 from the cylinder block 4, the cylinder head 10 is pressed against the cylinder head gasket 23 by tightening the screws 25 which protrude through straw 20 in the cylinder housing 10 and into the corresponding threaded hole 26 in the cylinder block 4. The cylinder head gasket 23 is compressed by the clamping forces which arise but so much so that the cylinder head 10 is brought into abutment against the projecting flange 29. Upon continued tightening of the screws 25, the projecting rigid surface 28 is affected by a clamping force via the dead compression cylinder head gasket gasket. 23. Since the seat shoulder 15 at the lower part of the cylinder liner 7 abuts the bar shoulder shoulder 14 on the hatrum cradle (Fig. 2) and therefore offers resistance to the kidin forces, the cylinder liner 7 which bends slightly outwards in its transverse direction is deformed while the cylinder liner 7 gets into -Uri: the earth 8 and the support surface 28 approaches the level of the awe surface 33 of the cylinder block 4, before finally reaching the same level. When the cylinder liner 7 is firmly pressed into the hatch space 8, the cylinder head 10 has reached the antigen against the cylinder block 4 and further applied clamping force is distributed to the cylinder block 4 and the cylinder head 10.

Thus, when the screws 25 are tightened, the cylinder head 10 is pressed against the cylinder liner 7. As a result, on the guild of the projecting surface 28, due to the geometric design of the integral components, tensile stresses in the perforated holes 26 in the cylinder block 4. These tensile stresses are superimposed with the variants. loads which arise during operation of the combustion engine 3 and increase the risk of breakage and crack formation in the cylinder block 4, especially connection to the threaded tails 26 and at the cylinder liner 7 storage in the cylinder block 4. To reduce the tensile stresses and claimed risk of fracture and cracking a cylinder head gasket 23 is used according to the invention. Figure 4 shows a cylinder head gasket 73 in the form of a metal plate, suitably a copper plate or a soft carbon steel plate, preferably covering the entire surface between the cylinder head 10 and the cylinder block 4 (Fig. 2) and in which which corresponds to the incineration grid, continuous h.OI 37 SUM answers mo t cooling ducts in the combustion engine and mcd through hall 38 which corresponds to lubricating oil ducts. In addition to this, the cylinder head gasket 23 is averted with a through-hole 39 for guide pins which is used 6 538 136 to facilitate assembly of the cylinder head at the cylinder block and a recirculating end 40 for state rods for valve control.

The cylinder head gasket 23 is also formed with a number of gel-independent mounting hall 43.

Through vane and one of the ends 43, one of the screws 25 for fixing the cylinder head 10 to the finder block 4 and for compressing the cylinder head gasket 23 for gas and liquid opaque tangling between said parts is intended to extend (Fig. 2). After compression, there is an acute packing pressure, diminstone in an annular ontrade around the combustion chamber, which packing pressure creates an effective gas sealing arrangement 24, an onnide radial outside the gas sealing arrangement 24, and radial outside a tanked one-drum shaft 9 through the genorn.gdend.e haleklet 36, liar. 23 varies in thickness and consists of at least a thicker part 45 and a thinner part 46. The thicker part 45 is dashed in the figure. Tests have shown that when the cylinder head gasket 23 is cold, it is thicker on this. When mounting the cylinder head against the cylinder block, Idggs set a Rat pressure on the selected row of cylinders on the cylinder block under increased pressure, so that the tensile stresses that occur when the cylinder heads are tightened or reduced to become grain-pressed. This is very advantageous for the material to be able to withstand clear load during operation and reduces the risk of cracks occurring. In a prefabricated liner, the thicker part 45 is ring-shaped and tops around the gas filling arrangement 24, the gas filling arrangement 24 and the 45 bar essentially the same. thickness. The mounting groove 43 for the cylinder head screws is formed in the annular part 45, the thicker part 45 and the thinner part 46 are arranged. radieht outside the thicker part 45. The thicker part 45 extends in this embodiment Over an area n.ara fi.5rbranningsrummet but radial -u.tanfor gasatningsarrangem.anget 24 saint around the screws d.dr OW risk of breakage and crack formation is present and decreases darigenom derma. risk. Figure 5 shows a cylinder head gasket 23 which is mirror-watered as in Figure 4 and which shows two alternative embodiments of the thicker part 45. In the other embodiment I open the thicker part 45, which is stretched marked, at least divided around at least one mounting part 43. wherein the thinner part 46 is arranged radially outside the thicker part 45. In the second embodiment iii: the thicker stretch-marked part 45 is ring-shaped and tops around at least one mounting hall 43, the thinner part 46 being arranged radially outside the thicker part 45. Also in these embodiments the thicker part 45 is provided & there is an increased risk of broil and cracking is present to reduce this risk. The cylinder head gasket 23 shown in Figures 4 and 5 has a thickness of between 0.5 mm and 2 mm, preferably 1 mm and the difference in thickness Indian the thicker part 45 and the thinner part 46 fir 0.05 - 0.25 mm, preferably 0.1 mm. The surface of the thicker part 45 or the sum of the surfaces on. several thicker parts 45, of the cylinder head gasket 23 constitute between 1% and 50% of the top surface of the toroidal gasket gasket 23, but preferably 10% of the total area.

The difference in thickness between the thicker part 45 and the thinner part 46 of the cylinder head gasket 23 can be achieved by plastic processing or by the cylinder head gasket 23 being preferably coated with an extra layer of material, the disk defining the thinner part 46 and the disk with the extra layer of material defining the thick part 45. The extra layer of material can be a pit, a washer, heat-resistant gurarni or some other material such as Murat- de pdfrestningar a cylinder head gasket 23 selected father. The extra layer of material can be attached to the plate by latination, vulcanization, gluing or by any other suitable method.

The invention is, of course, not limited in any way to the above-described embodiments, but many modifications to modifications thereof will be apparent to one skilled in the art, except that it deviates from the basic spirit of the invention as defined in the appended claims. . 8

Claims (9)

Arrangement in an internal combustion engine (3) comprising at least one cylinder (5) formed sum a cylinder liner (7) mounted in a cylinder block (4), which cylinder (5) is closed in one of its ends by a cylinder head (10), wherein between the cylinder (5) and the cylinder head (10) is arranged a cylinder head gasket (23) formed with at least one gas sealing arrangement (24) and designed to be compressed to the effect of action by pressing the cylinder head (10) against the cylinder block (4) with cylinder screws (25) SOIT1 extends through the hollow (20) cylinder head (10), through the mounting hall (43) in the cylinder head gasket (23) and into the corresponding threaded hole (26) in the cylinder head (4), characterized in that the cylinder head gasket (23) abuts against a support surface (28) of the cylinder liner, which support surface (28) holds extends. a right [Ilya on an upper surface (33) of the cylinder block (4) in an unloaded layer of the cylinder liner (7), the support surface (28) being formed with an annular projecting portion 30, the center of the projecting pair (30) being a bottom surface of the cylinder head (10) is formed with a corresponding annular recess (31), the cylinder head (10) being pressed against the cylinder liner (7) with. the cylinder screws (25) are tightened, the cylinder head gasket (23) being compressed by the resulting clearing forces, the support surface (28) being affected by the clamping forces via the compressed cylinder head gasket (23) so that the cylinder liner (7) is bent in its transverse direction and the support surface (28) the upper surface (33) of the cylinder inner block (4), and wherein the cylinder head gasket (23) in an area radially outside the gas filling arrangement (24) has varying thiocides and consists of at least a thicker part (45) and a thinner part (46), that the tensile stresses sum arising in the cylinder block (4) when the cylinder block is pulled are reduced or phase to become compressive. Arrangement according to claim 1, characterized in that the thicker part (45) is annular Deb Riper around the gas sealing arrangement (24), the number part (46) being arranged radially outside the thicker part (45). Arrangement according to claim 2, characterized in that the mounting hall (43) is formed in the annular thicker part (45). Arrangement according to claim 2, characterized in that the cylinder head gasket (23) at the gas sealing arrangement (24) and the thicker part (45) have substantially the same thickness. 9 538 136 Arrangement according to claim 11, characterized in that the thicker part (45) at least partially runs around at least one mounting hall. (43) with the thinner ("cleft (46) Jr arranged row or outside the thicker part (45). Arrangement according to claim 5, characterized in that the thicker part (45) is annular and tops around at least one mounting hall (43). Arrangement according to claim 6, characterized in that the thicker part one (45) has the form of a washer and is fixed to the thinner part (46). Arrangement according to the preceding claims, characterized in that. the cylinder head gasket (23) has a thickness of 0.5-2.0 mm. Arrangement according to claim 8, characterized in that the top yoke gasket (23) has a thickness of 1.0 mm. Arrangement according to one of the preceding claims, characterized in that the difference in thickness between the thicker part (45) and the thinner part (46) is 0.05 - 0.25 mm. Arrangement according to claim 10, characterized in that the difference in thickness between the thicker part (45) and the thinner part (46) is 0.1 mm. Arrangement according to one of the preceding claims, characterized in that the surface of the thicker part (45) of the cylinder head gasket (23) constitutes between 1% and 50% of the total surface of the cylinder head gasket (23). Arrangement according to claim 12, characterized in that the surface of the thicker (Jae.5) of the cylinder head gasket (A) constitutes 10% of the total surface. Arrangement according to claim I. characterized in that the cylinder head gasket (23) is disc-shaped and coated with an extra layer of material, the disc defining the thinner part (46) and the disc with the extra layer of material! defines the thicker part (45). Arranger 2 according to claim 11, characterized in that the internal combustion engine 3) is a diesel engine with several. Combustion chamber (6) encircled In the cylinder block (4), each combustion chamber (6) is delimited by a cylinder liner (7), a piston (, -) or a single cylinder, cylinder head (10), and taken with a dip by a single cylinder head gasket2 (23). Internal combustion engine comprising at least one arrangement according to any one of claims 1-14. to17. lordon innefatia de attnin.stone cit arrangriangenligt n) atentkraven 1-15. 11