US2170015A - Internal combustion engine - Google Patents

Description

Aug. 22, 1939. l H. FORb 2,170,015

INTERNAL COMBUS TION ENGINE Filed June 9, 1938 UNITED STATES PATENT OFFICE 2,170,015 INTERNAL COMBUSTION ENGINE Henry Ford, Dearborn, Mich., assignor to Ford Motor Company, Dearborn, Mich., a corporation of Delaware Application June 9, 1938, Serial No. 212,724

6 Claims.

The object of my invention is to provide an internal-combustion engine wherein the cylinder bores are provided with improved hardened steel liners. The invention consists of improvements in the cylinder liner whereby heat transfer from the liner to the cylinder block is improved and more convenient removal, of the liner, when desired to replace same, is possible. It is necessary that an intimate contact be provided between the outer surface of the cylinder liner and the bore in the cylinder block in order that the transfer of heat between the two will prevent burning of the liner in spots. Reduced cost of the liner is also 'an object of this invention.

In the past it has been customary to form such liners as tubular sleeves which were either pressed or screwed into the cylinder bore. screwthreads are run the length of the cylinder bore and the periphery of the sleeve threaded to 0 screw into place good heat transfer is obtained but the cost of this construction and difliculty of installation make it prohibitive for a medium priced engine. On the other hand, if the cylinder liner is pressed into the bore, both the liner and cylinders must be manufactured to extremely accurate dimensions in order that the press fit will not loosen under the repeated heatings occurring in the operation of themotor. An excessively high retaining pressure is also undesirable because of the difliculty then experienced in removing worn liners.

A further object'of my invention is therefore to provide a cylinder liner which will have sufficient contact with the bore in the block to conduct the ,required amount of heat from all parts of the liner, and which also may be removed from the block withlittle labor.

, The customary procedure inthe past in in-- stalling such liners has been to immediately insert the liner in the block after cooling the liner in liquid air. When the liner and block return to a uniform temperature the liner will-have expanded to fit the block with a shrink fit. The objection to this procedure has been that it is im- 5 possible to remove such liners from the block unless the pressure produced by the expansion of a the liner is controlled within very close limits and the cylinder bore and liner manufactured to very close limits. Temperature diiferential, as above mentioned, may be used to install the liner with-a high pressure but obviously cannot be' used to remove the liner. Worn liners must be pressed out of the block. If an excessive removal pressure is applied the material of the liner collapses so that it simply wedges the liner tighter in the block. For this reason, liners which are passed or shrunk into place are invariably manufactured with a relatively thick wall to stand up under the pressure required to remove the liner.

An object of this invention is thus to provide a liner which has only a fraction of the thickness of the conventional liner and which is adapted to be retained in place with a relatively high pressure, but which may be conveniently removed, when desired. It would be impossible to remove by pressing a conventional cylinder liner having a wall thickness of the dimensions of my improved liner. However, I have provided novel means whereby the liner may be removed so that the disadvantages heretofore inherent with liners which have been shrunk in place are avoided in this construction.

Still a further object of my invention is to provide a cylinder liner, the upper end of which is shaped to coact with the cylinder head gasket and cylinder head to form a relatively smooth combustion chamber surface. It is highly desirable that the annular groove sometimes provided between the upper end of the liner and the cylinder head be eliminated, as carbon deposits in such grooves and causes pre-ignition. Y

With these and other objects in view,-my invention consists in the arrangement, construction and combination of the various parts of my improved device, as described in the specification, claimed in my claims, and illustrated in the accompanying drawing, in which:

Figure 1 shows a vertical central sectional view through a V-type motor having my improved cylinder liners installed therein.

Figure 2 shows an enlarged sectional view of the upper end of a cylinder bore andliner, showing the co-operation between the cylinder head and gasket and liner.

Figure 3 is a perspective view of my improved cylinder liner.

Figure 4 is a view of the fiat stock blank used to form the liner before it is rolled to its cylindrical shape, and I Figure 5 is a full sized view illustrating in dotted lines the position to which the liner may be bent to permit its removal from the cylinder bore.

Referring to the accompanying drawingJ have used the reference numeral ID to indicate the cylinder block of aV-type motor. V-type motor is shownit will be understood that this invention is applicable to any design of single or multi-cylinder engines. The cylinder block I0 is provided with cylinder bores l I, the upper Although a end of each bore being countersunk to a bellmouth shape as shown at 12.

My improved cylinder liner is formed from relatively thin flat sheet steel, 20 to 22 gauge cold rolled stock being preferred. The metal is out into blanks 13 of a width equal to the length of the bore I I and having a length slightly in excess of the circumference of the bore. The ends of the blank are then beveled by a broaching operation to the shape shown at I4. The flat blank I3 is then bent to a cylindrical shape so that an outwardly opening V-shaped groove I5 is formed by the beveled ends I 4, as shown in Figure 5. The blanks are broached to accurate lengths so that when they are rolled into cylinders the diameter of the cylinders is uniform to within very close limits. The cylinder is then held in position and three spots l6 are welded along the length of the V-groove l5. These spots are preferably spaced a short distance from each end of the cylinder. with one spot in the middle. Either a torch or arc welding may be used to form the spots. The spots 16 are only about an eighth of an inch in diameter and the outer surfaces of the welds are roughly ground so that they do not ex ceed the outside diameter of the liner. The top end of the liner is'then flared outwardly, as at IT, to fit the bell mouth I2 of the cylinder bore.

The liner as above formed is then heat treated, the preferred method consisting of conducting the liner through an ammonia nitriting furnace.

This heat treatment causes the surface of the sleeve to absorb a considerable amount of carbon so that it hardens upon quenching when removed from the furnace. The hardening or gas carbonizing process, as it is ordinarily termed, forms no part of this invention but is described to show a method of forming a preferred type of cylinder liner. When the liners are hardened by the above mentioned method relatively inexpensive steel may be used for the blank I3 and still a hard, long wearing liner results.

After the liner has been quenched it is then placed in a liquid air or dry ice compartment which lowers its temperature to 20 or 30 degrees below zero. After the liner has attained this low temperature it is removed from the refrigerated compartment and immediately inserted into the cylinder bore. Quickly the liner increases to the temperature of the block and expands into a tight shrink fit in the cylinder bore. If such liner were made as a solid tube, it would be impossible to remove same because sufficient pressure could not be applied to the upper end to overcome the friction of the shrink fit between the liner and the cylinder wall. A pressure great enough to overcome the shrink fit would rupture the thin wall of the liner and thereby cause same to wedge more tightly against the cylinder.

When it is. desired to remove the liner and insert a new one, it is only necessary that a drift or screw driver be driven down behind the flare Il adjacent to the abutting edges. The tool causes the upper corner of the liner blank to bend inwardly, as shown in dotted lines l8. A moderate tap upon the tool breaks the upper weld so that further pressure causes the bend to progress downwardly to the middle weld. The two remaining welds are in like manner broken. When the bend I8 is complete the circumferential pressure on the liner is removed so that it can be drawn out by hand with very little effort.

Were not the liner previously split it would be impossible to start a tool behind the wall, and even if this could be accomplished by providing a notch at the upper end of the block, it would be necessary that the interior of the liner be cut through the full length before it could be removed. This, of course, could not be done with a chisel, screw driver or manually operated tool without scoring up the cylinder bore. As the liner is hardened a slotting tool could not be used to accomplish this operation.

It will be noted from Figure 2 that the flared end of the liner projects a slight distance above the top of the cylinder block so that when the cylinder head I!) is fastened in place the gasket 20 will be pressed down upon the upper end of the liner to form a seal therewith. A relatively smooth contour of the inside of the combustion chamber is thus provided.

Among the many advantages arising from my improved construction, the use of relatively inexpensive fiat cold rolled sheet metal stock to form the liner reduces the cost of same materially. When such stock is gas hardened a wearing surface is produced equivalent to that of the most expensive tubular forged steel liner.

Furthermore, the liner being much thinner than the conventional cylinder liner has a greater coefficient of heat transfer therethrough so that a cooler liner results.

Still further, as the liner cannot and need not be pressed from the cylinder bore, it may be fitted therein with very high shrink fit pressure to thereby insure metal to metal contact at all points between the liner and the cylinder bore. Thus the transfer of heat between the liner and the bore is increased and the hot spots which frequently. occur where other types of removable liners are used are eliminated.

Some changes may be made in the arrangement, construction and combination of the various parts of my improved construction, without departing from the spirit of my invention, and it is my intention to cover by my claims such changes as may reasonably be included within the scope thereof.

I claim as my invention.

1. An internal-combustion engine having a cylinder bore therein into which a thin wall cylinder liner is expanded under relatively high pressure, said liner being formed with a parting line extending the length thereof, the material of the liner on each side of said parting line being fastened together only at spaced intervals therealong, for the purpose described.

2. An internal-combustion engine having a cylinder bore therein into which a cylinder liner formed of relatively thin sheet metal is expanded under relatively high pressure, said liner being rolled to cylindrical shape from a rectangular shaped sheet metal blank with the abutting edge of said cylinder fastened together only at spaced intervals therealong, for the purpose described.

3. An internal-combustion engine having a cylinder bore therein, a tubular cylinder liner formed of relatively thin sheet metal expanded into said bore under a relatively high pressure, said liner being formed from a rectangular shaped sheet metal blank, the abutting edges of said blank forming an outwardly opening V-shaped groove which extends the length of said liner, said abutting edges being discontinuously fastened together in said groove, for the purpose described.

4. An internalcombustion engine having a cylinder bore therein, a tubular cylinder liner formed of relatively thin sheet metal expanded into said bore under relatively high pressure, said liner being formed from a rectangular shaped sheet metal beveled to form an outwardly opening V -shaped groove which extends the length of said liner, saidblank, the abutting edges of said blank being abutting edges being welded together at only a relatively few spots s'paced therealong, for the purpose described.

'5. An internal-combustion engine having a cylinder bore therein, a cylinder liner comprising a relatively thin sheet metal tube expanded into said bore under relatively high pressure, said tube being rolled from a fiat sheet metal blank with the abutting edges of said liner fastened together only at spaced intervals therealong, the upper end of said liner being flared outwardly to fit a correspondingly countersunk end of said cylinder bore, a cylinder head gasket disposed over the flared end of said liner, said liner extending beyond the upper ,end of said cylinder bore sufficiently to project a short distance into said gasket, and a cylinder head secured over said gasket, said cylinder head and the inner edge of said gasket and said liner forming a relatively smooth compression chamber for said engine.

6. An intemal-combustion engine having a cylinder bore therein, a cylinder liner comprising a relatively thin sheet metal tube expanded into said bore under relatively high pressure, the upper end of said liner being flared outwardly to fit a correspondingly countersunk end of said cylinder bore, a cylinder head gasket disposed over the flared end of said liner, said liner extending beyond the upper end of said cylinder bore suificiently to project a short distance into said gasket, and a cylinder head secured over said gasket, said cylinder head and the inner edge of said basket and said liner forming a relatively smooth compression chamber for said engine.

HENRY FORD.

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