Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
  • F02F1/00—Cylinders; Cylinder heads 
  • F02F1/02—Cylinders; Cylinder heads  having cooling means
  • F02F1/10—Cylinders; Cylinder heads  having cooling means for liquid cooling
  • F02F1/16—Cylinder liners of wet type
  • F02F1/166—Spacer decks
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
  • F02F11/00—Arrangements of sealings in combustion engines 
  • F02F11/002—Arrangements of sealings in combustion engines  involving cylinder heads
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B3/00—Engines characterised by air compression and subsequent fuel addition
  • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
  • F02F7/00—Casings, e.g. crankcases or frames
  • F02F7/006—Camshaft or pushrod housings
  • F02F2007/0063—Head bolts; Arrangements of cylinder head bolts

Definitions

• This invention relates generally to a thermal stop cylinder head joint and sealing system that limits thermally induced loads from the cylinder head to the cylinder block or liner and, more particularly, to head gaskets for sealing receipt between a cylinder head and a cylinder block or liner of an internal combustion engine.
• the cylinder head joint is a critical sealing joint in an internal combustion engine, particularly in high compression diesel engines.
• diesel engines that employ flanged cylinder liners further complicate sealing of the cylinder head joint.
• a spacer plate or plates are provided in the cylinder head joint between the cylinder head and block.
• the spacer plates provide clearance for the flange of the cylinder liner to be mounted on the cylinder block in the cylinder head joint, rather than in a counter bore of the cylinder block, to reduce crack initiation in the cylinder block. Additionally, the spacer plates distribute mechanically induced cylinder head loads into the cylinder block without concentrating the loads on any one part of the cylinder block; i.e., the liner flange to cylinder block interface. Typically, the spacer plates are constructed of a thermally conductive material such as aluminum to distribute thermally induced cylinder head loads and reduce high thermal unit loading of the cylinder block.
• U.S. Patent No. 5,125,551 to Slee discloses a combination cylinder head gasket and combustion gas seal which includes heat conductive elements between integral metal fire rings in an attempt to reduce thermal loading of the gasket.
• the cylinder head gasket disclosed in U.S. Patent No. 5,125,551 adds complexity and cost while still being susceptible to failure due to non-uniform heating during engine operation.
• the combination cylinder head gasket and combustion gas seal shown in U.S. Patent No. 5,125,375 to Vuk is adapted for use with a specially machined cylinder liner in an attempt to resist blowout of the integral combustion gas seal.
• the flange of the cylinder liner is machined frustoconical and cooperates with the cylinder head to produce a wedging action that resists radial expansion of the combustion gas seal when clamped between the cylinder head and liner.
• the gasket disclosed in U.S. Patent No. 5,125,375 relies on a preset clearance between the cylinder flange and cylinder head to provide the necessary wedging action with the frustoconical contour. Should the cylinder head be improperly assembled or should the preset clearance become insufficient due to creep of the combustion gas seal, the gasket can be subject to blowout.
• a cylinder head gasket that combines a flexible sealing element with a metal gasket body to prevent detachment of the sealing element from the gasket body is shown in U.S. Patent No. 5,033,189 to Desverchere et al.
• Flexible sealing elements on either side of the metal gasket body are joined together through slots in the metal gasket body to reduce the risk of the sealing elements becoming detached therefrom.
• One disadvantage of this construction is that the flexible sealing element is formed integral with the metal gasket body, thus requiring the entire gasket body to be discarded should a portion of the flexible sealing element fail . What is needed is an improved gasket and gasket sealing system for, use in the cylinder head joint of an internal combustion engine that overcomes the aforementioned deficiencies of the gaskets disclosed in U.S. Patent Nos.
• Such a gasket sealing system should be compatible with diesel engines employing flanged cylinder liners and spacer plates at the cylinder head joint. Ideally, such a gasket sealing system should be inexpensive to manufacture and easily installed and, together with the spacer plate, should reduce thermal loading from the cylinder head to the combustion gas seal and cylinder block or liner.
• a sealing system for a cylinder head joint of an internal combustion engine comprising a spacer plate having a top mounting surface and a bottom mounting surface, the spacer plate including a plurality of engine fluid through holes for communicating engine fluids thereacross, means for clamping the spacer plate between the cylinder head and the cylinder block with the top mounting surface contacting the cylinder head mounting surface and the bottom mounting surface contacting the cylinder block mounting surface, and a first plurality of discrete engine fluid gaskets received in the plurality of engine fluid through holes clamped between the cylinder block and the cylinder head, the first plurality of discrete engine fluid gaskets sealing engine fluids within the plurality of engine fluid through holes.
• a replaceable gasket comprising a rigid substrate including an upper sealing surface, a lower sealing surface and a plurality of connecting holes extending between the upper sealing surface and the lower'sealing surface, the rigid substrate having a shape corresponding to the predetermined shape of the through hole of the spacer plate and being sized for receipt in the through hole, and a seal including an upper sealing element received against the upper sealing surface and adapted for sealing receipt between the upper sealing surface and the cylinder head, a lower sealing element received against the lower sealing surface and adapted for sealing receipt between the lower sealing surface and the cylinder block, and a plurality of connecting elements received through the plurality of connecting holes and interconnecting the upper sealing element with the lower sealing element.
• a method for sealing a cylinder head joint of an internal combustion engine comprising the steps of obtaining a spacer plate having a top mounting surface and a bottom mounting surface, the spacer plate including a plurality of engine fluid through holes for communicating engine fluids thereacross, placing the spacer plate on the cylinder block with the bottom mounting surface contacting the cylinder block mounting surface, obtaining a first plurality of engine fluid gaskets corresponding to the plurality of engine fluid through holes, placing the first plurality of engine fluid gaskets in the plurality of engine fluid through holes, placing the cylinder head on the spacer plate with the cylinder head mounting surface contacting the top mounting surface, and simultaneously clamping the spacer plate and the first plurality of engine fluid gaskets between the cylinder head and the cylinder block.
• a combustion gas seal comprising a malleable sealing ring disposed between a cylinder head and a cylinder block or liner of an internal combustion engine.
• the malleable sealing ring is crushable between the cylinder head and the cylinder block or liner to form a seal when clamped therebetween.
• a backing ring is disposed adjacent to and radially outward of the malleable sealing ring for supporting the malleable sealing ring against deformation during operation of the engine.
• an improvement in a cylinder head joint of an internal combustion engine including a combustion gas seal and a spacer plate, the spacer plate being clamped at a predetermined clamp load between a cylinder head and a cylinder block, the cylinder block including a cylinder liner having a flanged portion extending upwardly from the cylinder block through a bore of the spacer plate, the improvement comprising the spacer plate being clamped in direct contact between the cylinder head and the cylinder block and the combustion gas seal being clamped in the bore of the spacer plate in sealing contact between the flanged portion of the cylinder liner and the cylinder head.
• a method for sealing a cylinder head joint of an internal combustion engine comprising the steps of obtaining a spacer plate having a top mounting surface and a bottom mounting surface, the spacer plate including at least one cylinder liner through hole for receiving a cylinder liner therein, placing the spacer plate on the cylinder block with the bottom mounting surface contacting the cylinder block mounting surface and with the cylinder liner received in the at least one cylinder liner through hole, placing a combustion gas seal in the cylinder liner through hole onto the cylinder liner, placing the cylinder head on the spacer plate and the combustion gas seal, and clamping the spacer plate between the cylinder head and the cylinder block and the combustion gas seal between the cylinder head and the cylinder liner.
• One object of the present invention is to provide an improved gasket sealing system for the cylinder head joint of an internal combustion engine.
• Another object of the present invention is to provide an improved combustion gas seal or "fire ring" for use in the cylinder head joint of an internal combustion engine.
• Yet another object of the present invention is to provide an improved head gasket for sealing engine fluids such as coolant and ⁇ or oil communicated between the cylinder head and cylinder block.
• Still yet another object of the present invention is to provide an improved thermal joint between the cylinder head and cylinder block of an internal combustion engine that reduces thermal unit loading of the cylinder block.
• Yet another object of the present invention is to provide an improved head joint that reduces thermal loading of the combustion gas seal during engine transients.
• Fig. 1 is a partial side cross-sectional view depicting a cylinder head joint of a diesel engine according to one embodiment of the present invention.
• Fig. 2 is an exploded cross-sectional view of the cylinder head joint of Fig. 1.
• Fig. 3 is a top plan view of a combustion gas seal or "fire ring" of the cylinder head joint of
• Fig. 4 is a partial side cross-sectional view of the combustion gas seal of Fig. 3.
• Fig. 5 is a partial side cross-sectional view of an alternate combustion gas seal for use in the cylinder head joint of Fig. 1.
• Fig. 6 is a top plan view of a spacer plate having coolant ferrules for sealing coolant ports and cylinder head bolts and a replaceable gasket for sealing a lifter compartment of the cylinder head joint of Fig. 1.
• Fig. 7 is a side cross-sectional view of the coolant ferrule taken along line 7-7 of Fig. 6.
• Fig. 8 is a top plan view of the replaceable lifter compartment gasket of Fig. 6.
• Fig. 9 is a partial side cross-sectional view of the replaceable lifter compartment gasket taken along line 9-9 of Fig. 8.
• a diesel engine 10 is shown incorporating a cylinder head joint 11 according to one embodiment of the present invention.
• Engine 10 includes a cylinder head 12 mounted clamped on a cylinder block 14 via a plurality of cylinder head bolts 16.
• a cylinder liner 18 is slidably mounted within a bore 20 of cylinder block 14.
• Cylinder liner 18 defines a cylinder bore 19 and includes a flanged portion 22 extending upwardly from cylinder block 14 into the cylinder head joint.
• a spacer plate 24 is mounted between cylinder head 12 and cylinder block 14 and includes a cylinder liner through hole 26 for receiving flanged portion 22 of cylinder liner 18 therein. Spacer plate 24 distributes both mechanical and thermally induced cylinder head loads from the cylinder head into the cylinder block without concentrating the cylinder head loads at any one portion of the cylinder block.
• a head gasket in the form of a gasket plate was mounted clamped between the spacer plate 24 and engine block 14 to seal across engine fluid passageways such as the seal lifter compartment and coolant ports.
• a head gasket incorporating a combustion gas seal or "fire ring” was mounted clamped between the cylinder head and spacer plate.
• the present invention eliminates the need for head gaskets between the spacer plate and cylinder head and between the spacer plate and cylinder block and relies instead on discrete gaskets and seals at the various specific fluid interfaces across the cylinder head joint.
• FIG. 2 the cylinder head joint 11 of the present invention is shown in greater detail.
• the top and bottom mounting surfaces 28 and 30, respectively, of spacer plate 24 are mounted contacting corresponding mounting surfaces of cylinder head 12 and cylinder block 14.
• any insulative gaps present across the cylinder head joint are eliminated so that heat is conducted evenly and directly across the cylinder head joint.
• the solid abutment of the spacer plate between the cylinder head and cylinder block resists thermal loading of the combustion gas seal and reduces motion of the cylinder head relative to the combustion gas seal and cylinder block. As a result, distortion and wearing of the combustion gas seal is minimized to provide a more stable cylinder head joint.
• spacer plate 24 is constructed of a conductive material such as aluminum so that the heat loading conducted from cylinder head 12 is substantially evenly distributed through spacer plate 24 prior to being conducted into cylinder block 14. As such, severe temperature gradients from the cylinder head are reduced across spacer plate 24 to reduce thermal loading of cylinder block 14.
• thermal growth characteristics of an aluminum spacer plate relative to those of the cylinder head, block and liner ensure a tight cylinder head joint at engine operating temperatures.
• discrete gaskets are provided situated across the spacer plate between the cylinder head and cylinder block or liner to selectively seal the various fluid interfaces across the cylinder head joint.
• a discrete combustion gas seal or fire ring 32 is provided clamped between flanged portion 22 of cylinder liner 18 and cylinder head 12 to seal only combustion gasses.
• Fire ring 32 is received in an annular slot 34 machined in liner 18 so that a predetermined clamp load is applied across ring 32.
• the clamp load applied to fire ring 32 is set by the predetermined clearance in slot 34 between the cylinder liner and the cylinder head, rather than solely by the cylinder head bolt load, when the cylinder head is clamped in place against spacer plate 24 onto block 14.
• the clamp load applied to fire ring 32 is selectable independent of the clamp load applied by the cylinder head bolts across the spacer plate. Also, by eliminating the gaskets between the cylinder head and spacer plate and between the spacer plate and cylinder block, the tolerance stack and associated load variation across the combustion gas seal is reduced to permit increased nominal loading of the combustion gas seal . Similarly, torque relaxation of the cylinder head bolts is reduced since the overall assembly of the cylinder head joint is less susceptible to dimensional change due to creep of the various gaskets and seals. Referring now to Figs. 3 and 4, combustion gas seal or fire ring 32 is shown in greater detail.
• Fire ring 32 includes an annular sleeve 36 having an upper sealing member 38 adapted for sealing contact against cylinder head 12 and a lower sealing member 40 adapted for sealing contact against cylinder liner 18.
• a malleable sealing ring 42 is disposed in annular sleeve 36 between upper sealing member 38 and lower sealing member 40.
• Malleable sealing ring 42 is crushable within annular sleeve 36 to provide a conforming seal between the cylinder head and the cylinder liner when clamped in place.
• a backing ring 44 is disposed in annular sleeve 36 radially outward of malleable sealing ring 42.
• Backing ring 44 is constructed of a material having sufficient strength to support sealing ring 42 against deformation at the high combustion gas pressures. For example, at gas pressures in excess of 13,790 kPa (2000 psi) and including a factor of safety as known in the art, backing ring 44 is constructed of a material having an ultimate tensile strength in the range of about 482,633 kPa (70,000 psi) to about 896,318 kPa (130,000 psi) and, preferably, of about 737,739 kPa (107,000 psi) for supporting the sealing ring against a design gas pressure of approximately 27,579 kPa (4000 psi) .
• annular sleeve 36 is generally U-shaped in cross-section to wrap around malleable sealing ring 42 and restrain sealing ring 42 in place.
• means for centering are provided in the form of a plurality of peripherally spaced tabs 46 attached to annular sleeve 36. Tabs 46 cooperate with flanged portion 22 of cylinder liner 18 to locate gasket 36 centered both within annular slot 34 and about cylinder bore 19
• annular sleeve 36 and sealing ring 42 are constructed of stainless steel, wherein sealing ring 42 is fully annealed having a hardness in the range of 78-88 on a Rockwell 15-T scale.
• backing ring 44 is similarly constructed of stainless steel having a hardness of at least 20 on a Rockwell C scale to provide the necessary strength for supporting the fully annealed sealing ring.
• Fire ring 32 is indexed as well relative to the cylinder bore and liner to prevent rotation of the gasket during assembly. For example, in Fig.
• a plurality of peripherally spaced slots 48 are provided in spacer plate 24 corresponding to tabs 46 so that tabs 46 are received in slots 48 when assembled in place in annular slot 34.
• Other discrete combustion gas seals or fire rings are contemplated that include a malleable sealing ring and backing ring for sealing receipt between cylinder head 12 and cylinder liner 18.
• a malleable sealing ring and backing ring for sealing receipt between cylinder head 12 and cylinder liner 18.
• FIG. 5 an alternate combustion gas seal or fire ring 50 is depicted employing a two-piece construction.
• a malleable sealing ring 52 similar to sealing ring 42 seals between the cylinder head and liner.
• a separate backing ring 54 prevents blowout of sealing ring 52 under high combustion pressures.
• the backing ring 54 further incorporates means for centering and indexing sealing ring 52 about cylinder bore 19 in the form of integral downwardly extending tabs 56. Similar to the discrete combustion gas seal
• spacer plate 24 is shown in greater detail including a variety of discrete engine fluid seals contained by the spacer plate.
• the spacer plate 24 includes a plurality of coolant ports 60 and 62 disposed about cylinder liner through hole 26 for communicating engine coolant between the cylinder head 12 and cylinder block 14.
• cylinder head bolt through holes 64 for receiving cylinder head bolts 16 therethrough.
• Adjacent to the liner flange through hole 26 is an irregular-shaped crankcase through hole 66 which provides clearance for a valve lifter and communicates with a valve lifter compartment.
• coolant ferrules 67 are disposed in coolant ports 60 and 62 for sealing engine coolant between the cylinder head and the cylinder block.
• the present invention further utilizes coolant ferrules 67 to seal about cylinder head bolts 16, thereby preventing any coolant leakage from corroding the cylinder head bolts and preventing any combustion gas leakage from relaxing the cylinder head bolt material.
• coolant ferrules 67 are generally cylindrical in shape and include a cylindrical metal core 68 encased in a rubber or plastic sheath 69.
• Sheath 69 extends beyond core 68 so that when the ferrule is clamped between the cylinder head and block, only the rubber or plastic sheath 69 deforms to provide a liquid-tight seal supported between the cylinder head and the cylinder block by the metal core 68. Because the present invention eliminates gasket plates between the spacer plate and cylinder block, an additional seal 70 is required for sealing across spacer plate 24 about the lifter compartment. Gasket 70 is irregularly shaped to conform to the shape of the lifter compartment through hole 66.
• gasket 70 includes a rigid substrate 71 having an upper sealing surface 72, a lower sealing surface 74, and a plurality of connecting holes 76 extending between upper sealing surface 72 and lower sealing surface 74.
• a flexible sealing element 77 is received across the rigid substrate and includes an upper sealing element 78 for sealing between upper sealing surface 72 and cylinder head 12 and a lower sealing element 80 for sealing between lower sealing surface 74 and cylinder block 14.
• Sealing elements 78 and 80 are interconnected by a plurality of connecting elements 81 received through the connecting holes 76. Connecting elements 81 restrain the sealing elements 78 and 80 across substrate 71 to prevent the sealing elements 78 and 80 from detaching therefrom.
• Sealing elements 78 and 80 are preferably sized larger than the connecting elements 81 so that, although being attached to one another, sealing elements 78 and 80 deform independently when clamped to seal separate from one another.
• the cross-sectional width of sealing elements 78 and 80 is depicted larger than the cross-sectional diameter of connecting element 81.
• the cross-sectional width of each of sealing elements 78 and 80 is at least twice as great as the cross-sectional diameter of connecting element 81 to provide sufficient sealing area for surfaces 72 and 74 to support sealing elements 78 and 80 independent of one another.
• the height of sealing elements 78 and 80 from sealing surfaces 72 and 74, respectively, is depicted shorter than the length of connecting element 81 between sealing surfaces 72 and 74.
• the length of connecting element 81 between sealing surfaces 72 and 74 is at least two times the height of each sealing element 78 and 80 from sealing surfaces 72 and 74 and, in the specific embodiment shown in FIG. 9, about two to three times the height of each sealing element 78 and 80 from sealing surfaces 72 and 74.
• Rigid substrate 71 includes a rectangularly shaped cross-sectional core portion 82 defining upper sealing surface 72 and lower sealing surface 74 and containing connecting holes 76 therebetween. Additionally, a backing portion 84 is provided to further support the sealing elements. The backing portion 84 extends above upper sealing surface 72 to define a shoulder 86 for restraining the upper sealing element 78 in place. Similarly, backing portion 84 extends below lower sealing surface 74 to define a shoulder 88 for restraining lower sealing element 80 in place. As such, the flexible sealing elements 78 and 80 are further restrained from being detached from the substrate during assembly. To further bolster shoulders 86 and 88, the backing portion 84 is generally T-shaped in cross-section and includes gussets 90 for reinforcing shoulders 86 and 88 across the T-shaped cross-section.
• gasket 70 is supported independent of spacer plate 24 by the rigid substrate 71 and, therefore, is easily replaceable. As such, refurbishment of gasket 70 does not require replacement of the spacer plate. Further, the gasket is easily constructed of molded plastic to facilitate incorporation of the various shoulders and gussets for added strength and rigidity. Gasket 70 includes locating pins 92 which are received in corresponding slots 94 of spacer plate 24 to restrain gasket 70 in place during assembly. In one specific embodiment, gasket 70 is shaped to provide clearance for cylinder head bolts 16, as shown in Fig.
• substrate 71 is constructed of a rigid plastic and the sealing elements are constructed of a flexible elastomer.
• rigid substrate 71 is constructed either of polyethersulfone (PES) or an approximately 30% by weight glass-filled polymeric amide such as Nylon and the sealing elements are constructed either of a highly saturated nitrile rubber (HSN) or a fluorocarbon such as a vinylidene fluoride - hexafluoropropylene copolymer (Viton) .
• PES polyethersulfone
• HSN highly saturated nitrile rubber
• fluorocarbon such as a vinylidene fluoride - hexafluoropropylene copolymer
• spacer plate 24 is placed on cylinder block 14 with bottom mounting surface 30 contacting a corresponding mounting surface of the cylinder block and with flanged portion 22 of cylinder liner 18 received in cylinder liner through hole 20.
• a plurality of appropriately sized coolant ferrules 67 corresponding to the plurality of coolant ports 60 and 62 of the spacer plate are placed one for one and contained in the plurality of coolant ports.
• a second plurality of appropriately sized coolant ferrules 67 corresponding to the plurality of cylinder bolt through holes 64 are placed one for one about cylinder head bolts 16 and contained in the plurality of cylinder head bolt through holes.
• Lifter compartment gasket 70 is placed in lifter compartment through hole 66 and oriented with tabs 92 received in corresponding slots 94 of the spacer plate.
• Combustion gas seal 32 is placed in slot 34 on the top surface of cylinder liner flange 34.
• the combustion gas seal is centered about cylinder bore 19 during assembly by locating tabs 46 over flanged portion 22.
• Combustion gas seal 32 is indexed in place by inserting tabs 46 into slots 48 of spacer plate 24.
• Tabs 46 cooperate with spacer plate 24 to maintain combustion gas seal 32 in place on cylinder liner 18 during assembly.
• Cylinder head 12 is clamped onto cylinder block 14 via cylinder head bolts 16 with the mounting surface of cylinder head 12 contacting top mounting surface 28 of spacer plate 24 and combustion gas seal 32. When clamped, cylinder head 12 and cylinder liner 18 define a predetermined assembly clearance therebetween in cylinder liner through hole 26.
• Spacer plate 24 is clamped at a first predetermined clamp load between cylinder head 12 and cylinder block 14, and combustion gas seal 32 is clamped in the predetermined assembly clearance at a second predetermined clamp load selectable independent of the first predetermined clamp load.
• the cylinder head bolt load applied across the spacer plate during assembly can be selected sufficiently high to accommodate the differential thermal expansion across the cylinder head joint without loading the combustion gas seal at assembly.
• the combustion gas seal load can be selected sufficiently high at assembly to maintain a tight gas seal at peak cylinder pressures without simultaneously loading the remaining fluid seals and cylinder head bolts.

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• 1994
  • 1994-07-07 EP EP94922096A patent/EP0711382A1/de not_active Withdrawn
  • 1994-07-07 CA CA 2167796 patent/CA2167796A1/en not_active Abandoned
  • 1994-07-07 WO PCT/US1994/007564 patent/WO1995004217A1/en not_active Application Discontinuation
  • 1994-07-07 AU AU72557/94A patent/AU7255794A/en not_active Withdrawn
  • 1994-07-07 JP JP7505829A patent/JPH09500944A/ja active Pending

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