Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D15/00—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor
  • B22D15/02—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor of cylinders, pistons, bearing shells or like thin-walled objects
• • 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 
  • F02F1/24—Cylinder heads
• • 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 
  • F02F1/24—Cylinder heads
  • F02F1/26—Cylinder heads having cooling means
  • F02F1/36—Cylinder heads having cooling means for liquid cooling
  • F02F1/38—Cylinder heads having cooling means for liquid cooling the cylinder heads being of overhead valve type
• • 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 
  • F02F1/24—Cylinder heads
  • F02F2001/249—Cylinder heads with flame plate, e.g. insert in the cylinder head used as a thermal insulation between cylinder head and combustion chamber
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49229—Prime mover or fluid pump making
  • Y10T29/4927—Cylinder, cylinder head or engine valve sleeve making

Definitions

• the invention relates to a cylinder head Gussrohteil for producing a cylinder head for diesel-fueled internal combustion engines, with a finished machined state for mounting on a corresponding sealing surface of an engine block certain sealing surface which is formed on a sealing surface portion of the cylinder head Gussrohteils whose thickness in the cast state Has machining allowance with respect to its nominal thickness obtained after a machining machining of the sealing surface, and comprises a combustion chamber area which is assigned to a molded-in combustion chamber in the engine block.
• the invention further relates to a molten cylinder cast cylinder head for diesel-fueled internal combustion engines, comprising a machined sealing surface for mounting on a corresponding sealing surface of an engine block, comprising a combustion chamber region associated with a combustion chamber formed in the engine block.
• the invention also encompasses a method for casting a cylinder head casting blank, in which a molten metal, in particular a light metal melt, is poured into a casting mold which comprises a mold cavity depicting the cylinder head casting, which has a boundary surface forming a sealing surface on the cylinder head casting blank and in which after casting, solidification and molding of the cylinder head Gussrohteils the sealing surface is machined by means of a machining by in the region of the sealing surface casting material is removed over a thickness to a finished for mounting on a corresponding sealing surface of an engine block To produce sealing surface.
• a molten metal in particular a light metal melt
• the combustion chamber In cylinder heads for diesel internal combustion engines, especially in direct injection engines, the combustion chamber has no dome-shaped geometry, as is usually provided for cylinder heads for gasoline engines, but is level incorporated in the equally flat sealing surface, with the diesel cylinder head in the assembled state at its associated sealing surface of the respective engine block is present.
• the combustion chamber region of the cylinder head is in this way in the sealing plane to the engine block.
• a machining allowance is usually pre-cast in the cylinder head casting blank, which is cut off during the finishing of the cylinder head.
• the abraded in the course of finishing provided as a processing allowance additional thickness of the sealing surface bearing portion of Cylinder head blank usually 2 mm to 3 mm. The cutting removal of this thickness makes it possible to produce the sealing surface with the required flatness with high precision.
• the combustion chamber area of the cylinder head is subjected to the highest stress due to the high pressures and high temperatures occurring in diesel engines.
• This load leads in particular in cylinder heads cast from light metal alloys on the valve seats and valve webs, which are usually incorporated into their combustion chamber areas, to an increased susceptibility to cracking.
• This vulnerability is particularly problematic in view of the desire for even more resilient cylinder heads, which is levied on the part of the manufacturer and user of diesel engines with regard to the highest possible power yield.
• the load capacity of the valve seats can be improved in the region of the combustion chamber, for example by pouring elements made of higher-strength metals.
• the effort associated with the pouring of the valve seats and the measures required for their sufficiently strong integration into the light metal of the cylinder head cause additional manufacturing expense. The same applies to the possibility of strength and - A -
• the invention has the object to provide a readily producible Cylinder Head Gussrohteil from which can be easily produced a cylinder head for diesel engines with optimized load capacity.
• a suitably trained, in particular made of a light metal alloy, casting technology with subsequent machining finishing cylinder head for diesel engines should be specified, which also withstands the increased demands on the strength of such cylinder heads permanently.
• the invention should also provide a method suitable for producing such cylinder heads.
• this object has been achieved on the basis of a cast cylinder raw part of the type specified above, that the processing allowance of the sealing surface portion in the combustion chamber region of the sealing surface is at most 15% of the excess of the sealing surface portion in the remaining area of the sealing surface in such Gussrohteil.
• the invention is based on the finding that the static and dynamic properties of the combustion chamber area encompassed by the sealing surface of the cylinder head to be produced are decisively influenced by the formation of the cast structure.
• the structural fineness which depends essentially on the solidification rate, is of particular importance in this case.
• the solidification is directed by heat extraction through the mold and runs at the contact surface between the mold and in the mold filled melt fastest.
• By proposing to limit the thickness of the machining allowance present in the combustion chamber area to a minimum it is now achieved that the rapidly solidified cast structure which is near the surface of the combustion chamber also follows the unavoidable machining on the surface of the surface required for producing the required flatness of the sealing surface Combustion area not removed, but preserved.
• the mechanical properties are correspondingly good there, compared with the areas of the cast cylinder head which are further in the interior and slower in the solidification.
• the combustion chamber area thus retains the beststarrte structure and can therefore be charged higher for longer life.
• the solution of the above-stated object accordingly is that the cylinder head according to the invention in the combustion chamber adjacent the surface thereof has a cast structure corresponding to the cast structure, which in adjacent to the surface Area of the sealing surface before the machining finishing is available.
• the boundary surface of the casting mold comprises an elevation which forms a combustion chamber region in the sealing surface of the cylinder head casting blank.
• the elevation has a surface extending essentially parallel to the boundary surface, which is arranged at a distance from the sealing surface which is at least 85% of the thickness of the material removed from the sealing surface in the course of the chip-removing finish machining.
• the combustion chamber area formed in the sealing surface of the cylinder head is already produced close to the exhaust gas of the cylinder head so that in the combustion chamber area at the unavoidable after machining for the production of their flatness machining the sealing surface only a minimal Material removal takes place. In this way, a rapidly solidified cast structure of fine structure is retained in the combustion chamber area of the finished cylinder head covered by the sealing surface.
• the property improvements achieved according to the invention can be further optimized by minimizing the machining allowance in the combustion chamber region of the sealing surface. Accordingly, advantageous embodiments of the Invention to restrict the machining allowance in the combustion chamber area to at most 10%, in particular 7% and more preferably at most 4% of the excess of the sealing surface portion in the remaining region of the sealing surface.
• the excess thickness in the combustion chamber for example, in the range of 0.1 mm to 0.2 mm, while in the remaining, the combustion chamber area comprehensive sealing surface in a conventional manner may continue to be 2 mm to 3 mm ,
• FIG. 1 shows a detail of a cast from a conventional cast aluminum alloy cylinder head Gußrohteils in cross section.
• FIG. 2 shows a section of a casting mold for casting the cylinder casting blank shown in FIG. 1 in cross section;
• Fig. 3 shows a detail of one of the cylinder head casting blank shown in Fig. 1 finished machined cylinder head in cross section.
• the cylinder head casting blank 1 has, at its lower side in the assembly position, a sealing surface 2 which extends over the entire width and length of the cylinder head casting blank 1. Already shown in Fig. 1, unprocessed GußrohCloud the sealing surface 2 is formed substantially flat.
• the sealing surface 2 comprises a combustion chamber region 3, which is assigned to a combustion chamber of an engine block, not shown here.
• a valve seat 4 for an intake valve, not shown, and a valve seat 5 are formed for an exhaust valve, also not shown.
• cooling channels 6, 7 are formed in the cylinder head casting blank 1, the connecting openings of which open out to the combustion chamber region 3 for connection to corresponding channels of the engine block in the sealing surface 2.
• the sealing surface 2 is carried with the combustion chamber region by a sealing surface section 8 extending over the width and length of the cylinder head casting green part 1. This in the region between the parallel to the sealing surface 2 extending portions of the cooling channels 6,7 and the sealing surface 2 existing sealing surface portion 8 is referred to in the jargon as "combustion chamber deck”.
• the thickness D of the sealing surface section 8 in the green casting state by a machining allowance D z2 is thicker than the nominal thickness D n of the sealing surface section 8 in the finished state shown in FIG.
• the machining allowance D z2 is for example 2 mm.
• the sealing surface section 8 in the combustion chamber region 3 is only slightly thicker than the prescribed nominal thickness Dn in the finished state. So is the cylinder head Cast ingot 1 the machining allowance D z3 in the combustion chamber area 3 only 0.1 mm, ie 5% of the machining allowance D z2 .
• a casting mold 100 For casting the cylinder head casting blank 1, a casting mold 100 is provided, which surrounds a casting mold cavity 104 with its side walls 101, 102 and its bottom 103. Casting cores 105 serve to image the valve seats 4, 5 and the cooling channels 6 and 7, respectively, of the cylinder head casting blank 1.
• a plane boundary surface 106 assigned to the casting cavity 104 is formed on the bottom 103 of the casting mold 100.
• This has in its combustion chamber region 3 of the cylinder head Gussrohteils 1 associated portion a survey 107, whose outer contour corresponds to the shape of the combustion chamber region 3.
• the survey 107 has at its free top a flat surface 108, parallel to the Boundary surface 106 is aligned.
• the height H, in which the surface 108 is arranged above the boundary surface 106, is 95% of the machining allowance Dz 2 to be applied to the cylinder head casting blank 1 in the region of the sealing surface 2 , in the present case 1.9 mm.
• the thick machining allowance D z2 in the area of the sealing surface 2 and the machining allowance D z3 in the combustion chamber area 3 are removed by a cutting milling operation, so that a flat sealing surface F is formed on the finished cylinder head Z, which is infinitely variable goes over her covered, equally flat combustion chamber region R.
• the material removal in the area of the sealing surface 2 is so great that only the relatively coarse cast structure is present on the free surface of the finished sealing surface F.
• the combustion chamber region R of the finished cylinder head Z there is still the fine cast structure produced by the rapid near-surface solidification due to the much smaller material removal there. This ensures that in the combustion chamber region R of the finished cylinder head Z increased strength and improved elongation values are present.
• the combustion chamber region R and the comprehensive sealing surface F of the cylinder head Z are in the same sealing plane.
• the combustion chamber region R covers the combustion chamber of the engine block assigned to it.
• Boundary surface 105 is arranged F sealing surface of the cylinder head Z R combustion chamber area of the cylinder head Z T depth over which a fine, rapidly solidified

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• General Engineering & Computer Science (AREA)
• Cylinder Crankcases Of Internal Combustion Engines (AREA)

Priority Applications (10)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (13)

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Citations (4)

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• 2005
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  • 2006-07-18 WO PCT/EP2006/064363 patent/WO2007017349A1/de not_active Ceased
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