US3168081A

US3168081A - Engine block assembly

Info

Publication number: US3168081A
Application number: US262780A
Authority: US
Inventors: Alfred F Bauer
Original assignee: Nat Lead Co
Current assignee: NL Industries Inc
Priority date: 1961-04-11
Filing date: 1963-03-04
Publication date: 1965-02-02
Anticipated expiration: 1982-02-02
Also published as: LU41514A1; GB949762A; NL277009A; CH387381A

Description

2 Sheets-Sheet 1 Original Filed April 11. 1961 INVENTOR.

ALFRED F. BAUER ATTORNEYS Feb. 2, 1965 A. F. BAUER 3,168,081

ENGINE BLOCK ASSEMBLY Criginal Filed April 11. 1961 2 Sheets-Sheet 2 INVENTOR.

ALFRED F. BAUER 2 WV a l o 07 4 6 E7 1 7 6 M Q a 4 w s 4 s 4 4 M a 2 9 u w A M l r T 5 w H H III F/ 7 I/ r 2 M m/MM M 8 2 3 4 m United States Patent 3,168,081 ENGINE BLOCK ASSEMBLY Alfred F. Bauer, Toledo, Ohio, assignor to National Lead Company, New York, N.Y., a corporation of New Jersey Continuation of application Ser. No. 102,187, Apr. 11, 1961. This application Mar. 4, 1963, Ser. No. 262,780 2 Claims. (Ci. 12341.74)

This application is a continuation of my application Serial No. 102,187, filed April 11, 1961, and now abandoned.

This invention relates to die-cast engine blocks for internal combustion engines, and is particularly directed to a two-piece structure which has certain advantages over present die-cast blocks.

Engine blocks for internal combustion engines made by the die-casting process have recently been introduced in this country. These blocks are made of an aluminum alloy in a single piece with cast-in gray iron cylinder liners and are assembled ultimately with a separate casting forming the cylinder head. The blocks are water-cooled and for this purpose are made with deep cavities around the cylinders extending from the top down to at least the lower limit of piston ring travel, and preferably somewhat below this point. In casting these blocks, the cylinder liners in the form of separate sleeves are initially placed over iemovable core pieces and then mounted on a fixture in the ejector half of the die. The cores that form the water passages are a part of the ejector die half and are necessarily long and thin because of the desired shape of the water passages in the finished casting.

The disposition of the core elements and the manner of forming the completed block as above set forth leads to several disadvantages which have heretofore not been corrected, but which are avoided by the present invention. First, the long, thin, core pieces for the water passages are difficult to extract and are subject to high thermal stresses and heat checking. These core pieces overheat easily and slow down the production because the heat poured into these water channel cores with every shot cannot dissipate fast enough through the thin steel sections. In the one-piece engine block with open-water jackets there is a compromise required between the thickness of the cores forming the water jackets which the die designer would like to make as strong and thick as possible, and the volume of the water jacket which the engine designer would prefer to have as thin as possible with good water circulation. If the die cores are widened or are made heavier to prevent overheating and premature failure of the die steel, then the volume of the cooling water in the jackets becomes so large that the engine heats up too slowly in cold weather. If the volume of the water jackets is made small, then the die cores become thin and weak and are subject to early failure from overheating and soldering. Production of the die-casting machine is thus reduced, and the die maintenance expense increases.

One of the most important disadvantages, however, of the one-piece engine block is that the space between Siamesed cylinders and the space at the open upper end of the water jacket around the cylinders is separated from the cylinders themselves only by a narrow surface equal in extent to the thickness of the liner plus the thickness of the aluminum wall cast around it, both of which are ideally made as thin as possible commensurate with an ability to resist the peak firing pressures encountered in the engine cylinders. The thin surface formed on the conventional one-piece engine block is subject on the inside to the peak firing pressures of the engine which are usually around 700 p.s.i., and on the outside to the low pressure 3,168,981 Patented Feb. 2, 1965 of the water jacket of only 10 or 15 p.s.i. The outer wall of the water jacket is, of course, at atmospheric pressure. As a result of the different pressures which the cylinder head gasket is called upon to retain, the gasket is made with different thicknesses to create higher sealing pressures at the narrow surfaces around the cylinder bores than at the surfaces at the outside of the water jacket. A so-called interference gasket has been developed which is, for example, 0.005" thicker in the areas of high pressure.

The us of interference gaskets and similar expedients has been found to cause a very substantial column loading on the walls of the cylinder barrels and to create a tensile stress in the outer walls of the casting. The loading on the cylinder barrels is sufficient to cause a decided outof-round condition so that a cylinder honed round with the cylinder head removed is oval when the head is in place and tightened down. The axis of the oval reverses from the top to the bottom of the cylinder. The use of interference gaskets thus presents a number of undesirable eifects.

The foregoing disadvantages of the present engine blocks are corrected by the present invention which provides a two-piece construction in which the ferrous alloy cylinder sleeves are die-cast integrally with a common deck plate. By this expedient the gasketed joint between the top of the engine cylinder and the water jacket disappears so that gas or water leakage cannot occur, and secondly the long, thin core pieces needed to form the cooling passages of the present engine aluminum alloy blocks are replaced by massive cores which need form only the outer block walls. Thus the casting ejects readily from the die. If desired, the joint between the two pieces which form the engine block can be made to occur, not in the plane of the top of the engine cylinder, but a considerable distance below this plane at a point where gasketing becomes a very simple matter, and very extensive surfaces oan be made available for gasketing purposes.

Further, the present invention makes it possible to utilize two different aluminum alloys, selected for different properties, in the formation of the engine block. The alloy for the cylinder barrels must be chosen for high wear resistance and best mechanical properties at elevated temperatures. The alloy for the crankcase may be selected for its castability, its high strength and resistance to distortion. In this way, it may become possible to eliminate the necessity for cast-iron liners, plating or similar treatment of the cylinder barrels and still retain all of the desirable characteristics of present diecast blocks.

The primary object of the present invention, therefore, is to provide a die-cast engine block which is easier to manufacture, and which has characteristics which represent improvements over the known die-cast blocks.

Other objects and advantages of the invention will be apparent from the following detailed description of a preferred embodiment thereof, reference being made to the accompanying drawings, in which:

FIG. 1 is a somewhat simplified, exploded perspective view of a plurality of engine cylinders which are diecast integral with a deck plate in accordance with the invention together with a cylinder head and a lower engine part;

FIG. 2 is a fragmentary, bottom view of the cylinders and deck plate of FIG. 1;

FIG. 3 is a fragmentary view in vertical cross section of the parts shown in FIGS. 1 and 2, when in assembled relationship;

FIG. 4 is a fragmentary view in vertical cross section similar to FIG. 3 but showing a modified connection between the upper and lower parts of an engine block assembly; and

FIG. 5 is a fragmentary view [in vertical cross section similar to FIG. 3, butshowing another modified connection between the upper and lower parts.

Referring to the drawing, and more particularly to FIG. 1, an upper cylinder assembly or engine part includes a plurality of cylinder barrels 12 die-cast integrally with a deckplate 14' and extending outwardly from one side thereof. with a plurality of bolt holes 16 and other openings 18 for cooling water, to allow the passage of push rods, etc. The cylinder barrels 12 have shoulders 20 near the lower ends thereof and can have internal cast'iron liners 22 (FIG. 3); if desired. 7

The upper assembly 10' is assembled with an engine block shell or lower engine part 24 which includes an upper portion of a crankshaft housing 26 die-cast integrally therewith. An outercooling chamber wall 28 extends upwardly from the housing 26, and a bottom wall 30 extends across the upper part of the crankshaft housing 26 to form the lower extremity of a cooling chamber 32 (FIG. 3).

The joint between the cylinder barrels 12 and the lower engine part 24 can be made in various manners, depending to some extent on the light metal alloys chosen for the two castings. If the same alloy is used for each, so that the coefiicient of thermal expansion is the same,

an adhesive seal may be used between mating tapered surfaces as will be subsequently described. If the parts are subject 'to different rates'of expansion, an annular seat 34 (FIGS. 1 and 3) may be formed in the bottom wall 30 for each of the cylinders 12 so that when the upper die-casting or part 10'is' assembled with the lower die-casting or part 24, the annular shoulders 20 of the cylinders 12- engage the annular seats 34 with a suitable seal such as a gasket 36 (FIG. 3) therebetween.

The deck plate 14 rests on a flange 38'of the cooling chamber wall 28 with a suitable gasket 40 therebetween. The sealing engagement at the two spaced portions of the cylinder wall 12 and the lower unit 24 thereby forms the cooling chamber 32, the outer wall of which constitutes the cooling chamber wall 28 and the inner wall of which constitutes the cylinder wall 12. The upper and lower walls of the chamber are formed by the flange 38 and the lower wall 30' of the part 24. This arrange ment will permit some differential expansion of the two" The upper casting 10 can be maintained in engage-j ment with the lower casting 24 by means of bolts or similar fasteners 42 which extend through a cylinder headdiag'rammatically indicated at 44 (FIG. 3) and threaded into holes 46 in the flange 38. This connection enables close contact to be maintained between the flanges 38' and the deck plate 14 and between the shoulders'2t) and the seats 34. If desired, the upper casting 10 can be fastened to the lower casting 24 by suitable bolts 'or'the like before the cylinder head 44 is attached.

Each of thecylinders 12 can beseparate, such as the cylinders 12B and 12C of FIG. 2, or the-cylinders can be cast in tandem orSiamesed, such as the cylinders 12A and 12B which are joined by a web 48 in this instance. Withtwo ormore cylinders so joined, the mass of each, in effect, is added to the other to provide each cylinder with additional mass and stiffness which reduces engine noise.

A modified engine block assembly is showri'in FIG. 4 with the joint between an upper engine die-casting 50 and a lower engine die-casting 52'made at a planeremoved from the top of the engine cylinder. In this instance, the outer cooling chamber wall is divided into ariuppersection 54 and a lower section 56 '

having'flanges

58 and 60 joined by a gasket 62 and a bolt 64. The upper cooling wall section 54 depends from and is integral. witha deck plate 66 in this instance and the lower section 56 is again integral with the crankshaft housing 68, but being only The deck plate 14 is formed 4 halfas high as the wall 28. The joint at the lower end of the water jacket or cooling chamber or between the upper casting 50 and the lower casting 52 is, in the form shown, made by inserting spaced O-rings 70 in grooves 72 in the lower casting 52. Thus the two castings can expand and contract longitudinally as the engine heats and cools in service and no strains will be set up in the engine cylinder. Bolts 74 join a cylinder head 76 to the deck plate 66. By bringing the gasketed joint 62 between the upper and lower castings away from the top of the engine cylinder, it is possible to improve the cooling of the critical areas of the block by improving the heat transfer at the top. In this form the deck plate can be made thinner since it is stiffened by the depending side walls 54 and is thus less subject to warping. I

In FIG. 5, a modified means for joining an upper diecasting 84 and a lower die-casting 86 is shown. In this instance, an upper connection between the units is similar to that shownin FIG. 3, a deck plate 88 being maintained in contact with a gasket 90 and a flange 92 of a cooling chamber wall 94 by means of bolts 95 which may be used also to fasten a cylinder head 96 to the block. In this instance, the deck plate 88 does not extend around the bolts 95 as does the deck plate 14 of FIG. 3, but is stopped short laterally of the clamping bolts. If the same aluminum or light metal alloy is used for both die-

castings

84 and 86, the lower connection between the castings may be provided by a tapered seat 97 formed on a bottom wall 98 and a similarly tapered shoulder 100 on a cylinder barrel 102. Between the mating tapered surfaces 97 and 100 a plastic bonding agent 104 may be inserted which when cured provides a water-tight 'seal therebetween. This bonding agent preferably is epoxy resin which is cured under suitable heat and pressure after the upper and lower castings are assembled.

With any of the three forms of connection between the upper and lower castings as shown in FIGS. 3, 4 and 5, any leakage that may possibly occur at the upper connection will be outside the engine cylinders, because the deck plates are always integral with the cylinder walls, whether or not the latter are integralwith part of the cooling chamber walls, as shown in FIG. 4. The upper connection is always made between at least part of a cooling chamber wall forming a portion of the lower casting and a portion of the upper casting, whether it be the deck plate or the downward extension of the deck plate forming an upper part of the cooling chamber wall as shown in FIG. 4. The lower connection is always made between a seat of the lower wall of the cooling chamber and the cylinder barrel extension of the upper casting. In either form of lower connection, leakage from the water jacket or cooling chamber is prevented, and this connection is relatively easy to make since it occurs at a point'where thermal and mechanical stresses are not excessive. I

Various modifications of the above described embodiments of the invention will be apparent to those skilled in the art, and it is to be understood that such modifications may be made without departing fromthe scope of the invention as defined in the appended claims.

What I claim is:

1. A die-cast light metal alloy engine block comprising: a lower die-cast section having an internal chamber with an open upper end and a bottom wall having an opening therein, said section having sidewalls which extend upwardly around said opening in said bottom wall and which terminate in a sealing surface surrounding said upper end of said internal chamber, a ferrous cylinder liner,an intermediate die-cast section of a light metal alloy having a deck plate with surfaces for effecting a seal with said upper sealing surface of .said sidewalls and a depending generally cylindrical'portion cast around and mechanically bonded to said cylinder liner, said depending generally cylindrical die-cast portion extending into said opening in said bottom of said lower die-cast section when said deck plate effectsa seal with said sealing surface surrounding said upper end of said internal chamber, and means eifecting a seal between said generally cylindrical die-cast portion in said bottom wall when said deck plate effects a seal with said sealing surface, whereby efiicient heat transfer from the inside of said ferrous liner is effected to a liquid cooling chamber which surrounds the liner and all portions of which chamber are of a non-rusting die-cast metal of high heat conductivity.

2. A die-cast light metal alloy engine block comprising: a lower die-cast section having an internal chamber with an open upper end and a bottom wall having spaced openings therein, said section having sidewalls which extend upwardly around the bottom wall having said openings there-through and which terminate in a sealing surface surrounding said upper end of said internal chamber; an intermediate die-cast section of a light metal alloy having a deck plate with surfaces for sealing engagement with said upper sealing surface of said sidewalls of said lower diecast section, and a plurality of depending cylinders cast integrally with said deck plate and positioned to align with respective ones of said spaced openings in said bottom wall of said lower die-cast section, said intermediate die-cast section having vertically extending integral webs connecting said deck plate and adjacent sections of depending cylinders to rigidify said intermediate die-cast section, the lower end of said depending die-cast cylinders extending into said openings in said bottom Wall of said lower diecast section, and means forming a water tight seal between the lower end of said die-cast cylinders in said bottom wall of said lower die-cast section whereby a rigid construction is provided and the clearance between said lower and intermediate die-cast sections forms a cooling chamber all portions of which are formed of a non-rusting die-east metal.

References Cited by the Examiner UNITED STATES PATENTS 867,075 9/07 Podhajsky 123--41.77 1,747,622 2/30 Daly 12341.63 1,928,411 9/33 Cross 12341.77 2,817,327 12/57 Brenneke 92149 2,893,358 7/59 Bauer 92-149 FOREIGN PATENTS 342,240 10/21 Germany.

RICHARD B. WILKINSON, Primary Examiner.

KARL J. ALBRECHT, Examiner.

Claims

1. A DIE-CAST LIGHT METAL ALLOY ENGINE BLOCK COMPRISING: A LOWER DIE-CAST SECTION HAVING AN INTERNAL CHAMBER WITH AN OPEN UPPER END AND A BOTTOM WALL HAVING AN OPENING THEREIN, SAID SECTION HAVING SIDEWALLS WHICH EXTEND UPWARDLY AROUND SAID OPENING IN SAID BOTTOM WALL AND WHICH TERMINATE IN A SEALING SURFACE SURROUNDING SAID UPPER END OF SAID INTERNAL CHAMBER, A FERROU CYLINDER LINER, AN INTERMEDIATE DIE-CAST SECTION OF A LIGHT METAL ALLOY HAVING A DECK PLATE WITH SURFACES FOR EFFECTING A SEAL WITH SAID UPPER SEALING SURFACE OF SAID SIDEWALLS AND A DEPENDING GENERALLY CYLINDRICAL PORTION CAST AROUND AND MECHANICALLY BONDED TO SAID CYLINDER LINER, SAID DEPENDING GENERALLY CYLINDRICAL DIE-CAST PORTION EXTENDING INTO SAID OPENING IN SAID BOTTOM OF SAID LOWER DIE-CAST SECTION WHEN SAID DECK PLATE EFFECTS A SEAL WITH SAID SEALING SURFACE SURROUNDING SAID UPPER END OF SAID INTERNAL CHAMBER, AND MEANS EFFECTING A SEAL BETWEEN SAID GENERALLY CYLINDRICAL DIE-CAST PORTION IN SAID BOTTOM WALL WHEN SAID DECK PLATE EFFECTS A SEAL WITH SAID SEALING SURFACE, WHEREBY EFFICIENT HEAT TRANSFER FROM THE INSIDE OF SAID FERROUS LINER IS EFFECTED TO A LIQUID COOLING CHAMBER WHICH SURROUNDS THE LINER AND ALL PORTIONS OF WHICH CHAMBER ARE OF A NON-RUSTING DIE-CAST METAL OF HIGH HEAT CONDUCTIVITY.