SE1450178A1

SE1450178A1 - Arrangements in an internal combustion engine

Info

Publication number: SE1450178A1
Application number: SE1450178A
Authority: SE
Inventors: Henrik Svärd; Fredrik Wilberfors; Tommy Andersson
Original assignee: Scania Cv Ab
Priority date: 2014-02-17
Filing date: 2014-02-17
Publication date: 2015-08-18
Also published as: SE538136C2

Abstract

Sammandrag En topplockspackning (23) är anordnad mellan ett cylinderblock (4) och ett cylinderhuvud (10) i en forbrdnningsmotor (3). Topplockspackningen (23) astadkommer en gas- och vdtskeogenomsldpplig tdtning mellan namnda delar och är utformad att komprimeras till tdtande verkan genom att cylinderhuvudet (10) pressas mot cylinderblocket (4) med skruvar (25) som strdcker sig genom cylinderhuvudet (10) in i skruvhal (26) i cylinderblocket (4). Ndr skruvarna (25) dras at uppsfar drag spanningar kring skruvhalen (26) i cylinderblocket (4). Dessa dragspanningar overlagras med de varierande belastningar som orsakas av motoms (3) drift vilket kan leda till okad risk for brott och sprickbildningar. Topplockspackningen (23) har varierande tjocklek vilket minskar dragspanningarna. Summary 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 compressed to a sealing effect by pressing the cylinder head (10) against the cylinder block (4) with screws (25) extending through the cylinder head (10) into the screw hall (26) in the cylinder block (4). When the screws (25) are tightened, tighten tension around the screw hole (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.

Description

Bakgrund och kand teknik Forbranningsmotorer av typen kolvmotorer innefattar en eller flera kolvar som nar motom är i drift vardera forflyttas fram och tillbaka i en cylinder anordnad i ett cylinderblock. Respektive cylinders ovre ande är tillsluten med hjalp av ett cylinderhuvud som avgransar ett forbranningsrum mellan cylinderhuvudet och kolvens ovre sida. Luft tillfors forbranningsrummet och komprimeras nar kolven forflyttas mot cylinderhuvudet. Vid lampligt tillfalle tillfors bransle till luften och nar kolven är nara sitt oversta laze i cylindem antands branslet som darefter forbranns och expanderar varigenom kolven pressas nedat i cylindem. Kolvens nedatriktade rorelse overfors och omvandlas till en rotationsrorelse i en vevaxel som overfor drivkraft till en fran motom utgaende axel. Background and prior art Internal combustion engine type piston engines comprise one or more pistons which, when the engine is in operation, are each moved back and forth in a cylinder arranged in a cylinder block. The upper spirit of each cylinder is closed by means of a cylinder head which defines a combustion chamber between the cylinder head and the upper side of the piston. Air is supplied to the combustion chamber and compressed when the piston is moved towards the cylinder head. In case of need, fuel is supplied to the air and when the piston is near its top laze in the cylinder, the fuel ignites which is then burned and expands, whereby the piston is pressed down into the cylinder. The downward movement of the piston is transmitted and converted into a rotational movement in a crankshaft which opposes the driving force to a shaft emanating from the motor.

Mellan cylinderblockets ovansida och cylinderhuvudets undersida är en topplockspackning anordnad. Topplockspackningen astadkommer en gas- och vatskeogenomslapplig tatning mellan namnda delar och är utformad att komprimeras till tatande verkan genom att cylinderhuvudet pressas mot cylinderblocket med skruvar som stracker sig genom hal i cylinderhuvudet och in i motsvarande gangade hal i cylinderblocket. Topplockspackningen kan utgoras av en metallskiva med jamn tjocklek dar extra mycket tatande packningstryck erhalles omedelbart kring forbranningsrummet genom att topplockspackningen komprimeras mot ett cylinderfoders axiellt ovre del som i obelastat tillstand skjuter ut en bit over cylinderblockets ovre yta. Det är aven kant, t.ex. genom US 6,113,109 att utnyttj a en topplockspackning som är lokalt tjockare i omradet omedelbart kring cylindern for att astadkomma forbattrad gastatning. Vid denna losning erhalles extra mycket tatande packningstryck kring forbranningsrummet genom att topplockspackningens tjockare omrade komprimeras mot cylinderblocket. A cylinder head gasket is arranged between the top of the cylinder block and the underside of the cylinder head. The cylinder head gasket provides a gas and liquid impermeable seal between said parts and is designed to be compressed to a tensile effect by pressing the cylinder head against the cylinder block with screws extending through a slide in the cylinder head and into the corresponding threaded slide in the cylinder block. The cylinder head gasket can be made of a metal plate of uniform thickness, where extra heavy packing pressure is obtained immediately around the combustion chamber by compressing the cylinder head gasket against the axial upper part of a cylinder liner which, in the unloaded state, projects a bit above the upper surface of the cylinder block. It is also an edge, e.g. by US 6,113,109 utilizing a cylinder head gasket that is locally thicker in the area immediately around the cylinder to provide improved gas supply. In this unloading, extra very tight packing pressure is obtained around the combustion chamber by compressing the thicker area of the cylinder head gasket against the cylinder block.

Vid kanda losningar maste en relativt stor kraft tillforas skruvforbandet for att komprimera topplockspackningen till tatande verkan, sarskilt da extra mycket tatande packningstryck 2 efterstravas i omradet omedelbart kring forbranningsrummet. Nar cylinderhuvudskruvarna dras at uppstar dragspanningar kring skruvhalen i cylinderblocket. Dessa dragspanningar overlagras med de varierande belastningar som orsakas av motorns drift vilket kan leda till stora kraftpakanningar i cylinderblocket och darmed okad risk for brott och sprickbildningar, sarskilt kring Mien i cylinderblocket men aven vid cylinderfodrets lagring i cylinderblocket. In the case of known discharges, a relatively large force must be applied to the screw connection to compress the cylinder head gasket to the aggravating effect, especially when extra very aggravating gasket pressure 2 is sought in the area immediately around the combustion chamber. When the cylinder head screws are tightened, tensile stresses arise around the screw hole in the cylinder block. These tensile stresses are superimposed with the varying loads caused by the engine's operation, which can lead to large force gaps in the cylinder block and thus an increased risk of breakage and cracking, especially around the Mien in the cylinder block but also during storage of the cylinder liner in the cylinder block.

Sammanfattning av uppfinningen Ett syfte med foreliggande uppfinning är att tillhandahalla ett arrangemang i en 10 forbranningsmotor vilket arrangemang minskar de dragspanningar som uppstar i cylinderblocket vid atdragning av skruvforbandet. SUMMARY OF THE INVENTION An object of the present invention is to provide an arrangement in an internal combustion engine which arrangement reduces the tensile stresses which arise in the cylinder block when tightening the screw connection.

I detta syfte utmarkes uppfinningen av vad som anges i den kannetecknande delen av patentkravet 1. To this end, the invention is defined by what is stated in the characterizing part of claim 1.

De fiesta material, och i synnerhet gjutjarn som cylinderblocket tillverkat av tal en betydligt stone vaxlande belastning vid ett overlagrat tryckspanningstillstand an vad det tal vid ett overlagrat dragspanningstillstand. Utforda prov har visat att nar topplockspackningen lokalt Ors tjockare, sarskilt vid de omraden av cylinderblocket dar sannolikheten att sprickor ska uppsta är storst, sa kan de dragspanningar som uppkommer nar cylinderhuvudsskruvarna dras at minskas eller fas att bli kompressiva. Detta är mycket fordelaktigt for materialets formaga att klara vaxlande belastningar under drift och minskar risken for att sprickor ska uppkomma. Prov har aven visat att uppfinningen kan anvandas for att reparera redan spruckna cylinderblock eftersom det kompressiva tryckspanningstillstandet som uppstar ndr uppfinningen tinmpas är sa stort att en spricka av en viss storlek kan tryckas ihop vilket eliminerar det lackage som annars sker genom sprickan. Most materials, and in particular cast iron such as the cylinder block made of speech, have a significantly more rocky load at a superimposed compressive stress state than the speech at an superimposed tensile stress state. Challenge tests have shown that when the cylinder head gasket is locally thicker, especially in those areas of the cylinder block where the probability of cracks occurring is greatest, the tensile stresses that occur when the cylinder head screws are pulled can be reduced or phase to become compressive. This is very advantageous for the material's ability to withstand changing loads during operation and reduces the risk of cracks occurring. Tests have also shown that the invention can be used to repair already cracked cylinder blocks because the compressive compressive stress condition that arises when the invention is thinned is so large that a crack of a certain size can be compressed which eliminates the leakage that otherwise occurs through the crack.

Vid en fordelaktig utforingsform är den tjockare delen ringformad och loper runt gastatningsarrangemanget varvid den tunnare delen är anordnad radiellt utanfor den tjockare delen. Den tjockare delen stacker sig d over ett omrade dar okad risk for brott och sprickbildning foreligger och minskar darigenom denna risk. 3 Vid ytterligare en fordelaktig utforingsform är den tjockare delen utformad kring monteringshal i topplockspackningen. Aven vid denna utforingsform är den tjockare delen anordnad i ett riskomilde for att minska risken for brott och sprickbildning. In an advantageous embodiment, the thicker part is annular and runs around the gas sealing arrangement, the thinner part being arranged radially outside the thicker part. The thicker part extends over an area where there is an increased risk of breakage and cracking, thereby reducing this risk. In a further advantageous embodiment, the thicker part is formed around the mounting hall in the cylinder head gasket. Also in this embodiment, the thicker part is arranged in a risk environment to reduce the risk of breakage and cracking.

Ovriga uppfinningen utmarkande sardrag framgar av de osjalvstandiga patentkraven och av efterfoljande beskrivning av en uppfinningen exemplifierande utforingsform. The other features of the invention are apparent from the dependent claims and from the following description of an embodiment exemplifying the invention.

Kort beskrivning av ritningen I det foljande beskrivs sasom exempel utforingsformer av uppfinningen med hanvisning till bifogad ritning dar: Fig. 1 visar ett fordon med en hytt under vilken en forbranningsmotor är anordnad. Brief Description of the Drawing In the following, embodiments of the invention are described by way of example with reference to the accompanying drawing, in which: Fig. 1 shows a vehicle with a cab under which an internal combustion engine is arranged.

Fig. 2 visar ett tvarsnitt genom den i figur 1 visade forbranningsmotorn. Fig. 2 shows a cross section through the internal combustion engine shown in Fig. 1.

Fig. 3 visar ett forstorat snitt av omradet A i figur 2. Fig. 3 shows an enlarged section of the area A in Fig. 2.

Fig. 4 visar en forsta utforningsform av en uppfinningsenlig topplockspackning. Fig. 4 shows a first embodiment of a cylinder head gasket according to the invention.

Fig. 5 visar en andra och en tredje utforningsform av en uppfinningsenlig topplockspackning. Fig. 5 shows a second and a third embodiment of a cylinder head gasket according to the invention.

Detaljerad beskrivning av foredragna utforingsformer av uppfinningen Foljande figurer visar valda delar ingdende i en forbranningsmotor som innefattar en eller flera kolvar vilka var och en är rorligt anordnad i en cylinder i ett cylinderblock. Cylindrarna är lampligen utformade som cylinderfoder som är monterade i harfOr avsedda utrymmen i cylinderblocket, vilket ocksa beskrivs i den fortsatta beskrivningen. Alternativt kan cylindrarna vara utformade direkt i cylinderblocket. Med cylinder avses darfor i den fortsatta beskrivningen det utrymme i vilket en kolv är rorligt anordnad, oberoende av om cylindern utgors av en integrerad del av cylinderblocket eller om den utgors av ett i cylinderblocket anordnat cylinderfoder. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION The following figures show selected parts contained in an internal combustion engine comprising one or more pistons each of which is movably arranged in a cylinder in a cylinder block. The cylinders are suitably designed as cylinder liners which are mounted in dedicated spaces in 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 therefore refers to the space in which a piston is movably arranged, regardless of whether the cylinder consists of an integral part of the cylinder block or whether it consists of a cylinder liner arranged in the cylinder block.

I figur 1 visas ett tungt fordon 1 i form av ett lastfordon med en hytt 2 under vilken en forbranningsmotor 3, exempelvis en dieselmotor, är anordnad. Vid alternativa utnyttjanden av forbranningsmotorn 3 kan denna vara anordnad i nagon annan fordonstyp, t.ex. i en personbil eller i en bat eller utnyttjas som en separat enhet for att driva ett elproducerande aggregat eller liknande. 4 I figur 2 visas ett tvarsnitt genom den i figur 1 visade forbranningsmotorn 3. Motorn 3 är i detta exempel en 6—cylindrig dieselmotor av radtyp men motorn 3 kan givetvis vara av annan typ och innefatta ett annat antal cylindrar utan att uppfinningstanken gar forlorad. Figure 1 shows a heavy vehicle 1 in the form of a truck with a cab 2 under which an internal combustion engine 3, for example a diesel engine, is arranged. In alternative uses of the internal combustion engine 3, this can be arranged in any other type of vehicle, e.g. in a car or in a bat or used as a separate unit to power an electricity generating unit or the like. Figure 2 shows a cross section through the internal combustion engine 3 shown in Figure 1. In this example, the engine 3 is 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 without losing the inventive idea.

Forbranningsmotorn 3 innefattar ett cylinderblock 4 i vilket är utformat sex cylindrar 5 med vasentligen cylindriska forbranningsrum 6 varav ett visas i figuren och som var och en avgransas i radiell riktning av ett cylinderfoder 7 som demonterbart inpassat i ett halrum 8 i cylinderblocket 4. Varje forbranningsrum 6 avgransas i axiell riktning av ett cylinderhuvud 10 och en for en fram och atergaende rorelse rorligt anordnad kolv 11. I forbranningsrummet 6 komprimeras luft och bransle som darefter forbranns sa att kolven 11, som via en vevstake 12 är ansluten till en ej visad vevaxel, med hjalp av den expansion som sker under den explosionsartade forbranningen forflyttas frail cylinderhuvudet 10 i riktning mot ett ej visat vevhus dar kolvens 11 rorelse overfors till en rotationsrorelse i vevaxeln. The internal combustion engine 3 comprises a cylinder block 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 which can be dismountably fitted in a cavity 8 in the cylinder block 4. delimited in the axial direction by a cylinder head 10 and a piston 11 movably arranged for a reciprocating movement. In the combustion chamber 6, air and fuel which is subsequently combusted are compressed so that the piston 11, which is connected via a connecting rod 12 to a crankshaft (not shown), with By means of the expansion which takes place during the explosive combustion, the cylinder head 10 is moved in the direction of a crankcase (not shown) where the movement of the piston 11 is transmitted to a rotational movement in the crankshaft.

Cylinderfodret 7 är av s.k. midstop-typ och är axiellt fixerat i halrummet 8, upptill med cylinderhuvudet 10 och nedtill med en ringfoimig baransats 14 pa halrumsvaggen vid dess nedre del. Cylinderfodret 7 stoder mot baransatsen 14 med en ringformig stodansats 15 pa cylinderfodrets 7 utsida. Baransatsen 14 och stodansatsen 15 anligger mot varandra Over ett ringformigt kontaktomrade i narheten av kolvens 11 nedre vandlage, dvs. i det omrade dar kolvens 11 nedatriktade rorelse overgar till en uppairiktad rorelse mot cylinderhuvudet 10. The cylinder liner 7 is of so-called midstop type and is axially fixed in the cavity 8, at the top with the cylinder head 10 and at the bottom with an annular bar insert 14 on the halter cradle at its lower part. The cylinder liner 7 abuts the bar shoulder 14 with an annular stand 15 on the outside of the cylinder liner 7. The bar shoulder 14 and the stand shoulder 15 abut each other over an annular contact area in the vicinity of the lower water layer of the piston 11, i.e. in the area where the downward movement of the piston 11 transitions to an upward movement towards the cylinder head 10.

Cylinderhuvudet dr pa kant sat utformat med inlopps- och avloppskanaler for tillforsel av luft till forbranningsrummet 6 och for evakuering av forbranningsgaser frail forbranningsrummet 6. Endast en kanal 16 visas i figur 2. Cylinderhuvudet 10 är dessutom utformat med urtag 17 for ej visade ventiler som samverkar med ej visade ventilsaten for styrning av lufttillforseln och for styrning av avgasevakueringen. I cylinderhuvudet 10 är aven utformat kylkanaler 18, urtag 19 for bran sleinsprutare for tillforsel av bransle till forbranningsrummet 6 samt hal for cylinderhuvudskruvar 25 for infastning av cylinderhuvudet 10 mot cylinderblocket 4. The cylinder head on the edge is designed with inlet and drainage channels for supplying air to the combustion chamber 6 and for evacuating combustion gases from the combustion chamber 6. Only one duct 16 is shown in figure 2. The cylinder head 10 is also designed with recesses 17 for cooperating valves (not shown). with the valve set not shown for controlling the air supply and for controlling the exhaust gas evacuation. The cylinder head 10 also has cooling channels 18, recesses 19 for fuel injectors for supplying fuel to the combustion chamber 6 and a slide for cylinder head screws 25 for fastening the cylinder head 10 to the cylinder block 4.

Mellan cylinderblockets 4 ovansida, och darmed aven cylindern 5, och cylinderhuvudets 10 undersida dr en topplockspackning 23 anordnad. Topplockspackningen 23 är utformad med atminstone ett ringformigt gastatningsarrangemang 24 som astadkommer en gas- och vatskeogenomslapplig tatning mellan namnda delar och är utformad att komprimeras till tatande verkan genom att cylinderhuvudet 10 pressas mot cylinderblocket 4 med cylinderhuvudskruvarna 25 som stracker sig genom halen 20 i cylinderhuvudet 10, genom hal i topplockspackningen 23 och in i motsvarande gangade hal 26 i cylinderblocket 4. Between the upper side of the cylinder block 4, and thus also the cylinder 5, and the underside of the cylinder head 10, a cylinder head gasket 23 is arranged. The cylinder head gasket 23 is formed with at least one annular gas sealing arrangement 24 which provides a gas and liquid impermeable seal between said parts and is designed to be compressed to a gripping effect by pressing the cylinder head 10 against the cylinder block 4 with the cylinder head screws 25 extending through the tail 20 in the cylinder head. through a hole in the cylinder head gasket 23 and into the corresponding aisle hall 26 in the cylinder block 4.

Vid den i figur 2 visade utforingsformen är ett cylinderhuvud 10 och en topplockspackning 23 anordnade vid vart och ett av sex forbranningsrum 6 men det är givetvis mojligt att utnyttja ett cylinderhuvud 10 och en topplockspackning 23 som stracker sig over ett antal forbranningsrum 6 utan att uppfinningstanken gar forlorad. En och samma topplockspackning 23 är i sadant fall utformad med ett antal genomgaende hal som vart och ett svarar mot ett forbranningsrum 6. In the embodiment shown in Figure 2, a cylinder head 10 and a cylinder head gasket 23 are arranged at each of six combustion chambers 6, but it is of course possible to use a cylinder head 10 and a cylinder head gasket 23 which extends over a number of combustion chambers 6 without the inventive idea lost. One and the same cylinder head gasket 23 is in such a case formed with a number of continuous halls, each of which corresponds to a combustion chamber 6.

Av figur 3, som visar ett forstorat snitt av omradet A enligt figur 2, framgar att cylinderfodret 7 vid sin mot cylinderhuvudet 10 vanda ande, vid sin radiellt inre del är utformad med en ringformig i axialled utskjutande flans 29. Flansen 29 utgor stod for den radiellt utanfor flansen 29 anordnade topplockspackningen 23 som dr anordnad kring forbranningsrummets 6 centrumaxel och som har en hojd som overstiger den utskjutande flansens 29 Md. Figure 3, which shows an enlarged section of the area A according to Figure 2, shows that the cylinder liner 7, when facing the cylinder head 10, is formed at its radially inner part with an annular axially projecting flange 29. The flange 29 forms the radially outside the flange 29 arranged the cylinder head gasket 23 which is arranged around the central axis of the combustion chamber 6 and which has a height which exceeds the projecting flange 29 Md.

Topplockspackningen 23 anligger mot en stodyta 28 som i hojdled stracker sig pa en hogre niva an cylinderblockets 4 byre yta 33 i cylinderfodrets 7 obelastade lage, dvs. nar cylinderhuvudet 10 annu inte pressas mot cylinderblocket 4 med skruvarna 25. Detta innebar att stodytan 28 i obelastat lage skjuter upp en bit over den ovre ytan 33 pa cylinderblocket 4. The cylinder head gasket 23 abuts against a support 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 position protrudes a bit above the upper surface 33 of the cylinder block 4.

Stodytan 28 är utformad med ett ringformigt utskjutande parti 30. Mitt for detta parti 30 är i cylinderhuvudets 10 bottenyta utformat ett motsvarande ringformigt urtag 31. De bada urtagen 30,31 bildar tillsammans en forstarkt tatningszon dar topplockspackningen 23 tillats deformerats vid atdragning av skruvarna 25 for att fylla ut det ringformiga urtaget 31 for att darigenom astadkomma en effektiv gas- och vatskeogenomslapplig tatning. The support surface 28 is formed with an annular projecting portion 30. In the middle of this portion 30 a corresponding annular recess 31 is formed in the bottom surface of the cylinder head 10. The two recesses 30,31 together form a reinforced sealing zone where the cylinder head gasket 23 is allowed to deform when tightening the screws 25 for filling the annular recess 31 to thereby provide an effective gas and liquid impermeable seal.

Cylinderfodret 7 är vid sin mot cylinderhuvudet 10 vanda ande, vid sin radiellt yttre del utformad med en ringformig forsankning 32 med en ovre yta som i hojdled stracker sig pa en lagre niva an stodytan 28 och pa vasentligen samma niva som cylinderblockets 4 ovre yta 33 1 6 cylinderfodrets 7 obelastade lage for att darigenom begransa stodytans 28 radiella utstrackning. The cylinder liner 7, at its facing towards the cylinder head 10, is formed at its radially outer part with an annular recess 32 with an upper surface which extends in height at a lower level from the support surface 28 and at substantially the same level as the upper surface 33 of the cylinder block 4. 6 unloaded bearing of the cylinder liner 7 to thereby define the radial extent of the support surface 28.

Vid montering av cylinderhuvudet 10 mot cylinderblocket 4 pressas cylinderhuvudet 10 mot 5 topplockspackningen 23 genom att skruvarna 25 som stracker sig genom halen 20 i cylinderhuvudet 10 och in i motsvarande gangade hal 26 i cylinderblocket 4 dras ht. Topplockspackningen 23 komprimeras darvid av de klamkrafter som uppkommer men inte sa mycket att cylinderhuvudet 10 bringas till anliggning mot den utskjutande flansen 29. Vid fortsatt atdragning av skruvarna 25 paverkas den utskjutande stodytan 28 av en klamkraft via den komprimerade topplockspackningen 23. Eftersom stodansatsen 15 vid cylinderfodrets 7 nedre del stoder mot baransatsen 14 pa halrumsvaggen (fig. 2) och darfor bjuder motstand mot klamkrafterna deformeras cylinderfodret 7 som bojs nagot utht i sin tvarriktning samtidigt som cylinderfodret 7 ror sig in i halrummet 8 och stodytan 28 narmar sig nivan for cylinderblockets 4 byre yta 33, for att till slut uppna samma niva. Nar cylinderfodret 7 är helt inpressat i halrummet 8 har cylinderhuvudet 10 uppnatt anliggning mot cylinderblocket 4 och ytterlig are palagd klarnkraft fordelas mellan cylinderblocket 4 och cylinderhuvudet 10. When mounting the cylinder head 10 against the cylinder block 4, the cylinder head 10 is pressed against the cylinder head gasket 23 by pulling the screws 25 extending through the tail 20 in the cylinder head 10 and into the corresponding threaded hall 26 in the cylinder block 4. The cylinder head gasket 23 is thereby compressed by the clamping forces which arise but not so much that the cylinder head 10 is brought into abutment against the projecting flange 29. Upon continued tightening of the screws 25, the projecting support surface 28 is affected by a clamping force via the compressed cylinder head gasket 23. 7 lower part abuts the bar shoulder 14 on the cavity cradle (fig. 2) and therefore offers resistance to the clamping forces, the cylinder liner 7 is deformed which is bent slightly in its transverse direction while the cylinder liner 7 moves into the cavity 8 and the support surface 28 approaches the level of the cylinder block 4. surface 33, to finally achieve the same level. When the cylinder liner 7 is completely pressed into the cavity 8, the cylinder head 10 has reached abutment against the cylinder block 4 and additional applied clearance is distributed between the cylinder block 4 and the cylinder head 10.

Nar skruvarna 25 dras at pressas saledes cylinderhuvudet 10 mot cylinderfodret 7. Darigenom uppstar pa grund av den utskjutande stodytan 28 samt pa grund av inghende komponenters geometriska utformning dragspanningar i de gangade halen 26 i cylinderblocket 4. Dessa dragspanningar overlagras med de varierande belastningar som uppkommer vid drift av forbranningsmotom 3 och okar risken for brott och sprickbildning i cylinderblocket 4, sarskilt i anslutning till de gangade Mien 26 och vid cylinderfodrets 7 lagring i cylinderblocket 4. For att minska dragspanningarna och darmed risken for brott och sprickbildning utnyttjas en uppfinningsenlig topplockspackning 23. When the screws 25 are tightened, the cylinder head 10 is thus pressed against the cylinder liner 7. As a result, due to the projecting support surface 28 and due to the geometric design of the components, tensile stresses arise in the threaded tails 26 in the cylinder block 4. These tensile stresses are superimposed on the varying loads. operation of the internal combustion engine 3 and increases the risk of breakage and cracking in the cylinder block 4, especially in connection with the gangmed Mien 26 and at the storage of the cylinder liner 7 in the cylinder block 4. To reduce the tensile stresses and thus the risk of breakage and cracking, a cylinder head gasket 23 is used.

I figur 4 visas en topplockspackning 23 i form av en metallskiva, ldmpligen en kopparskiva eller en mjuk kolstalsskiva, som foretradesvis tacker hela ytan mellan cylinderhuvudet och cylinderblocket 4 (fig. 2) och i vilken är utformat genomgaende hal 36 som svarar mot forbranningsrummet, genomgaende hal 37 som svarar mot kylkanaler i forbranningsmotorn samt med genomgaende hal 38 som svarar mot smorjoljekanaler. Utover detta är topplockspackningen 23 aven utformad med genomgaende hal 39 for styrpinnar som utnyttjas 7 for att underlatta montering av cylinderhuvudet vid cylinderblocket och ett genomga.ende hal 40 for stotstanger for ventilstyrning. Figure 4 shows a cylinder head gasket 23 in the form of a metal plate, typically a copper plate or a soft carbon steel plate, which preferably cuts the entire surface between the cylinder head and the cylinder block 4 (Fig. 2) and in which a continuous hall 36 corresponding to the combustion chamber is formed, through hall 37 which corresponds to cooling ducts in the internal combustion engine and with continuous hall 38 which corresponds to lubricating oil ducts. In addition to this, the cylinder head gasket 23 is also formed with a through hole 39 for guide pins which is used 7 to facilitate mounting of the cylinder head at the cylinder block and a through hole 40 for push rods for valve control.

Topplockspackningen 23 är aven utformad med ett antal genomgaende monteringshal 43. Genom vart och ett av Mien 43 är en av skruvarna 25 for att fixera cylinderhuvudet 10 vid cylinderblocket 4 och for att komprimera topplockspackningen 23 for gas- och vatskeogenomslapplig tatning mellan namnda delar, avsedd stracka sig (fig. 2). Efter komprimeringen foreligger ett okat packningstryck, atminstone i ett ringformigt omrade kring forbranningsrummet vilket packningstryck skapar ett effektivt gastatningsarrangemang 24. The cylinder head gasket 23 is also formed with a number of through-going mounting holes 43. Through each of the Mien 43 is one of the screws 25 for fixing the cylinder head 10 to the cylinder block 4 and for compressing the cylinder head gasket 23 for gas and liquid impermeable sealing between said parts, intended tightening sig (Fig. 2). After compaction, there is an increased packing pressure, at least in an annular area around the combustion chamber, which packing pressure creates an effective gas sealing arrangement 24.

I ett omrade radiellt utanfor gastatningsarrangemanget 24, och radiellt utanfor en tankt centrumaxel 9 genom det genomgaende halet 36, har topplockspackningen 23 varierande tjocklek och bestar av atminstone en tjockare del 45 och en tunnare del 46. Den tjockare delen 45 är streckmarkerad i figuren. Prov har visat att nar topplockspackningen 23 lokalt är tjockare pa detta satt laggs vid montering av cylinderhuvudet mot cylinderblocket ett okat tryck pa utvalda omi-aden pa cylinderblocket vilket okat tryck gOr att de dragspanningar som uppkommer nar cylinderhuvudsskruvarna dras at minskas eller fas att bli kompressiva. Detta är mycket fordelaktigt for materialets formaga att klara vaxlande belastningar under drift och minskar risken for att sprickor ska uppkomma. In an area radially outside the gas sealing arrangement 24, and radially outside a tanked center shaft 9 through the through hole 36, the cylinder head gasket 23 has varying 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 thicker locally, when mounting the cylinder head against the cylinder block, an increased pressure is applied to the selected areas of the cylinder block, which increased pressure causes the tensile stresses that arise when the cylinder head screws are reduced or become compressive. This is very advantageous for the material's ability to withstand changing loads during operation and reduces the risk of cracks occurring.

Vid en fordelaktig utforingsform är den tjockare delen 45 ringformad och loper runt gastatningsarrangemanget 24 varvid gastatningsarrangemanget 24 och den tjockare delen 45 har vdsentligen samma tjocklek. MonteringshMen 43 for cylinderhuvudskruvarna är utformade i den ringformade tjockare delen 45 och den tunnare delen 46 är anordnad radiellt utanfor den tjockare delen 45. Den tjockare delen 45 stracker sig vid denna utforingsform Over ett °mil& nara forbranningsrummet men radiellt utanfor gastatningsarrangemanget 24 samt kring skruvama dar okad risk for brott och sprickbildning foreligger och minskar darigenom denna risk. In an advantageous embodiment, the thicker part 45 is annular and runs around the gas sealing arrangement 24, the gas sealing arrangement 24 and the thicker part 45 having substantially the same thickness. The mounting heads 43 for the cylinder head screws are formed in the annular thicker part 45 and the thinner part 46 is arranged radially outside the thicker part 45. The thicker part 45 extends in this embodiment over a mileage combustion chamber but radially outside the gas sealing arrangement 24 and around the screws there. there is an increased risk of breakage and crack formation, thereby reducing this risk.

I figur 5 visas en topplockspackning 23 som är spegelvand den i figur 4 och som visar tva altemativa utforingsformer av den tjockare delen 45. Vid den ena utforingsformen loper den tjockare delen 45, som är strackmarkerad, kminstone delvis runt kminstone ett monteringsh5.1 43 varvid den tunnare delen 46 är anordnad radiellt utanfor den tjockare delen 45. 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 one embodiment the thicker part 45, which is stretched marked, runs at least partially around at least one mounting h5.1 43, the thinner part 46 is arranged radially outside the thicker part 45.

S Vid den andra utforingsformen är den tjockare strackmarkerade delen 45 ringformad och loper runt atminstone ett monteringshal 43 varvid den tunnare delen 46 är anordnad radiellt utanfor den tjockare delen 45. Aven vid dessa utforingsformer är den tjockare delen 45 anordnad dar okad risk for brott och sprickbildning foreligger for att minska denna risk. In the second embodiment, the thicker stretch-marked part 45 is annular and runs 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 arranged where there is an increased risk of breakage and cracking. available to reduce this risk.

Topplockspackningen 23 som visas i figurerna 4 och 5 har en tjocklek som är mellan 0,5 mm och 2 mm, foretradesvis 1 mm och skillnaden i tjocklek mellan den tjockare delen 45 och den tunnare delen 46 är 0,05 — 0,25 mm, foretradesvis 0,1 mm. Ytan hos den tjockare delen 45, eller summan av ytorna pa flera tjockare delar 45, av topplockspackningen 23 utgor mellan 1 % och 50 % av topplockspackningens 23 totala yta, men foretradesvis 10 % av den totala ytan. The cylinder head gasket 23 shown in Figures 4 and 5 has a thickness between 0.5 mm and 2 mm, preferably 1 mm and the difference in thickness between the thicker part 45 and the thinner part 46 is 0.05 - 0.25 mm. preferably 0.1 mm. The area of the thicker part 45, or the sum of the surfaces of several thicker parts 45, of the cylinder head gasket 23 constitutes between 1% and 50% of the total area of the cylinder head gasket 23, but preferably 10% of the total area.

Skillnaden i tjocklek mellan topplockspackningens 23 tjockare del 45 och tunnare del 46 kan astadkommas genom plastisk bearbetning eller genom att topplockspackningen 23 som foretradesvis är skivformad belaggs med ett extra lager material varvid skivan definierar den tunnare delen 46 och skivan med det extra lagret material definierar den tjocka delen 45. Det extra lagret material kan vara en plat, en bricka, varmebestandigt gummi eller nagot annat material som klarar de pafrestningar en topplockspackning 23 utsatts for. Det extra lagret material kan vara fast vid platen genom laminering, vulkanisering, limning eller genom flagon annan lamplig metod. The difference in thickness between the thicker part 45 of the cylinder head gasket 23 and the thinner part 46 can be achieved by plastic processing or by coating the cylinder head gasket 23 which is preferably disc-shaped with an extra layer of material, the disc defining the thinner part 46 and the disc with the extra layer of material defining the thick the part 45. The extra layer of material can be a plate, a washer, heat-resistant rubber or some other material that can withstand the stresses to which a cylinder head gasket 23 is subjected. The extra layer of material can be attached to the board by lamination, vulcanization, gluing or by flaking other suitable method.

Uppfinningen ar givetvis inte pa nagot satt begransad till de ovan beskrivna utforingsformerna utan en mangd mojligheter till modifikationer av dessa torde vara uppenbara for en fackman pa omildet, utan att denne for den skull avviker frau uppfinningens grundtanke sasom denna definieras i bifogade patentkrav. 9 The invention is of course not limited in any way to the embodiments described above, but a number of possibilities for modifications of these should be obvious to a person skilled in the art, without this deviating from the basic idea of the invention as defined in the appended claims. 9

Claims

Patent claims

Arrangement in an internal combustion engine (3) comprising at least one cylinder (5), which cylinder (5) is closed in one end of a cylinder head (10), a cylinder head gasket (10) being arranged between the cylinder (5) and the cylinder head (10). 23) formed with at least one gas sealing arrangement (24), characterized in that the cylinder head gasket (23) in an area radially outside the gas sealing arrangement (24) has varying thickness and consists of at least one thicker part (45) and a thinner part (46).

Arrangement according to claim 1, characterized in that the thicker part (45) is annular and runs around the gas sealing arrangement (24), the thinner 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.

Arrangement according to claim 1, characterized in that the thicker part (45) runs at least partially around at least one mounting hall (43), the thinner part (46) being arranged radially outside the thicker part (45).

Arrangement according to claim 5, characterized in that the thicker part (45) is annular and runs around at least one mounting hall (43).

Arrangement according to claim 6, characterized in that the thicker part (45) has the shape of a washer and is fixed to the thinner part (46).

Arrangement according to one of 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 cylinder head 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 area of the cylinder head gasket (23).

Arrangement according to claim 12, characterized in that the area of the thicker part (45) of the cylinder head gasket (23) constitutes 10% of the total area.

Arrangement according to claim 1, 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 defining the thicker part (45).

Arrangement according to claim 1, characterized in that the internal combustion engine (3) is a diesel engine with several combustion chambers (6) housed in the cylinder block (4), that each combustion chamber (6) is delimited by a cylinder liner (7), a piston (11), and a single cylinder head (10), and is tapped by means of a single cylinder head gasket (23).

Internal combustion engine comprising at least one arrangement according to any one of claims 1-14.

A vehicle comprising at least one arrangement according to any one of claims 1-15.