US1708426A - Antidetonating piston head for internal-combustion engines - Google Patents

Description

ANTIDE'IONATING PISTON HEAD FOR INTERNAL COMBUSTION ENGINES Filed Oct. 13, 1926 2 Sheet.s-Sheet,v l

INVENTOR ATTORNEY 5 A rils, 1929. A, MOORE 1,708,426

ANTIDETONATING PISTON HEAD FOR INTERNAL COMBUSTION ENGINES Filed Oct. 13, 1926 2 Sheets-Sheet 2 INVENTOR W m m/oyflk ATTORNEY Patented Apr. 9, 1929.

UNITED STATES PATENT OFFICE.

ARIJINGTON MOORE, 01 NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, TO HAXMOOR CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE.

'ANTIDETONA'IING PISTON HEAD FOR INTERNAL-COMBUSTION ENGINES.

Application filed October 13, 1926. Serial No. 141,289.

My invention relates to an anti-detonavertical internal combustion engine is employed herein for convenience of expression,

though not in a limiting sense, as the engine cylinders may be horizontal, or inclined, or. arranged in other ways.

According to the resent invention, the

16 upward extension of t e piston head is preferably of substantially helicoidal form, that is to say, it is highest at the center, and the remainder of the projection on the .PISFOII head is composed of a volute or winding ramp surface winding downwardly and outwardly on a gradual slant from the central part of the piston head to substantially the periphery thereof.

The-present invention also has for its object the converting of an internal combustion engine of any given compression ratio to one of higher ratio, as, or example, the changing of an engine ofexistiiig low compression tohigh compression, by attachment to the piston head of a crown having a substantially helicoid'al head surface, and will be best understood from the following descri tion of an embodiment of the invention s own in the accompanying drawings,

in which Fig. 1 is a sectional view of a valvein-head engine havin a substantially helicoidal piston head. ig. 2 is an enlarged plan view of the piston head with the crown attached. Fig. 3 is a fragmentary 'part sectional view on an enlarged scale. Fig. 4 1s an enlarged detail section of one form of screw lock. Fig. 5 is a similar view of a modified form of screw lock. Fig. 6 is a side view of a iston of somewhat modified formation. ig. 7 is a sectional view and Fig. 8 a plan view of a template for --"i'iisertion in a cylinder for drilling the holes in the piston head. Fig. 9 is a sectional view show ng the use of the template of Fig. 7 for drilling the holes, and Fi 10 is a detail sectional view of a modifie form of template.

The separate crown 10 has an under surface 12 adapted to fit closely on top of the head 14 of piston 16. Pistons are usually constructed with a fiat head and in such case the under surface 12 of the crown is flat.

The crown 10 is highest at its center, at which region it preferably terminates in the fiat nose 18, which may be of a diameter approximately 4 to of the piston diameter. From the nose or platen 18 the volute ramp surface 20 winds outwardly and downwardly to the peri hery of crown 10, the base of which is pre erably spaced back from the margin of the piston, as indicated at 22.

The substantially helicoidal crown comprising the described ortions is adapted to extend within the coin ustion chamber when the piston is at top center position. The convolutions of the volute slanting ramp surface 20 are connected by the substantially vertical riser surfaces 23, so as to avoid the presence of any sharp angles or fins. The number of convolutions of the ram surface may be varied substantially as desired, two complete convolutions 20 and 20 being shown in Fig. 2. In the modified form of crown 10 shown in Fig. 6, three complete convolutions 20', 20 and 20 are shown. The convolutions of the riser surfaces 23 correspond in number with the ramp convolutions. In making the crown 10, the narrowest part 24 of the outermost spiral is not carried down to a thin edge or fin, but is made of substantial height, as indicated by the dotted line 25, Fig. 3.

It will be apparent that by suitable choice of the dimensions of the crown 10 substantially any desired change of compression ratio can be obtained.

In order to avoid an unnecessary increase in the piston weig t the crown 10 is preferably made of light metal, such as aluminum. Where considerations of weight will permit, a higher heat conducting metal, such as copper, may be used.

It is essential that the fastening of the crown to the piston head he completely close and secure inorder to secure good heat conduction and to avoid loosening when the en-- gine is run at high speed, and I have devised a fastening means w ich meets these requirements.

In its preferred form such fastening means comprises a lurality of machine screws 26 with cylindrical heads 28, which are passed through holes 30 in the crown 10 and screwed into tapped holes 32 in the piston head. The

holes 30 are preferably countersunk, as indicated at 34, to receive the screw heads 28, and the depth of the countersunk recesses 34 is preferably the same as the height of the screw heads, so that same are flush with the crown platen surface 10.

When the screws 26 have been sore-ed home as tight as possible, they are permanently locked in place. The locking means preferably consists of a pin or dowel 36 driven into a hole 38 formed as by drilling partly in the margin of the screw head 28 and partly in the material of crown 10.

The dowel or pin 36 after being driven in is permanently secured in place so that it cannot be removed without drilling it out. Two modes of effecting this result are shown. In Figs. 2, 3 and 4 the pin 36, which is beveled off at its upper end, is locked by peening over the material of screw head 38 and crown 10, as indicated at 40, Fig. 4. In Fig. 5 a singlescrew thread 42 is tapped in the hole 38' and the pin 36, made a little longer than before to material, is peened an thereby expanded into the groove 42. Other. modes of securing the pin permanently in place may be resorted to, but that shown in Fig. 5 is deemed desirable, as the pin can conveniently be made of material suitable for the requiredv end deformation necessary to secure its permanent fastening into place. So secured,

the locking pin is proof against removal or loosening at all engine speeds and conditions, the screw cannot move, and the crown 10 cannot be loosened.

The crowns 10 or 10 can be made use of in engines of practically any construction, which will permit of increase in compression ratio. In Fig. 1 I have shown the crown or helicoidal portion on the piston 50 of an engine 52 of the valve-inhead type. In this type of engine the combustion chamber 54 is customarily formed partly in the top end of the cylinder 56 and partly in the cylinder head 58 and'the crown 10 projects into the combustion chamber and reduces the volume thereof when the piston is at top center, sub- .stantially as indicated in Fig. 1. A spark lug 60 is shown inoil'set relation to and facmg the helicoidal portion of the piston 50.

.This showing is illustrative only, as the crown can be used on heads of substantially an engine piston.

n making a service station application of the crown to the pistons of an automobile engine having a removable cylinder head, a

hardened template 60 may be slipped into the cylinder with the guide holes 62 accurately formed therein. The holes 64 are then drilled into the piston head, a stop being preferably used in drilling to gauge the depth of the hole, in order to avoid drilling (provide some extra igrcaaae through to the other side. In case the holes 62 are to be drilled through, this can be done by removing the crankcase and catching the drillings which fall through. The same tem plate is used in reversed position for drilling the holes 30 in the crown, a flange 66 being provided on the upperside of the template 60 and surrounding a socket or recess 68 therein for receiving and centering the crown, the holes 30 being drilled in the crown through the same guide holes 62 in the template 60.

In case of pistons being removed from the cylinder, as with an engine having a solid cylinder block without the head being made removable, the template 70 of Fig. 10 may be provided, having a guide recess 72 on its under side surrounded by the flange 7 4. The recess 72 is made just large enough to slip over the piston head and serves to accurately center the holes without resort to the cylinder walls for guiding.

Without being committed to any particular theory, it is my belief that the very conslidable increase in compression ratio (of the order of 6:1 or higher) possible to be used with my improved helicoidal crowns without detonation even when the engine is run on ordinary fuel without special antidetonation components, is due to turbulence created in the combustion chamberby contact of the gases with the crown surface on the intake stroke and by the crown serving to spread and excite the gases on the compression stroke and by a swirling or rotary turbulence due to the helical or screw formaand furthermore at firing the spiral steps in the crown will serve to breakup any pressure wave preceding the travel of flame after ignition. There may also be a surface combustion efi'ectof speeding up the flame travel by gas concentration adjacent to the additional upwardly extending surface area which is supplied by the crown, also apermitting of any pressure wave to expand after passing elf the variousstagcs of the ramp surface. i v

The extra surface area which may be provided' by the helicoidal crown formation at the same time that the combustion chamber volume is reduced assists in carrying away any excess heat which could cause detonation or produce areas of local incandescence likely to result in preignition, the turbulence of the gases being effective to secure uniform heat distributionand absence of such incandescent areas.

The highest benefits of the present invention are realized when complete combustion and absence of carbon deposits are obtained by the use of my improved system of combustion, involving the supplying to the engine intake above the throttle of exhaust gas and air at temperatures and in properpending application Serial No. 7 57,07 5, filed December 19th, 1924.

The subject matter of my invention disclosed herein and not claimed is disclosed and claimed in part in my copending application Serial No. 140,726, filed October 11, 1928, and renewed December 4, 1928, and in part in my copending application Serial No. 142.231, filed October 18, 1926.

This application is also a continuation in part of my copending application Serial No. 140,727, filed October-11, 1926.

I claim:

1. A. piston for an. internal combustion engine, having a separate substantially helicoid crown attached to,the head thereof.

2. A piston for internal combustion engines, a separate crown on the head of the piston, and means for securing the crown to the piston, comprising screws and locking pins for holding the screws against turning.

3. A piston for internal combustion engines, a separate substantially helicoid crown on the head of the piston, screws countersunk flush in the crown and screwed into the piston head, the screwhead and crowns being provided with locking pin holes-located partly in each, locking pins in said holes, the metal being peened over the locking pins so as to prevent loosening or removal thereof, except by drilling them out.

4. In an internal combustion engine having a cylinder and a combustion chamber therefor, a piston in said cylinder, a separate crown for said piston comprising a plurality of convoluted slanting ramp-like surfaces step related to one another, and permanent locked screw means for securing said crown to the piston head so that said crown will project into the combustion chamber.

5. A piston for internal combustion engines, a separate piston head crown having its up er surface comprising a plurality of spiral y volute steps, screws for securing said crown to pins permanently embedded within the screw and piston head material for permanently holding said screws against turning.

6. A piston for internal combustion engines comprising a substantially helicoidal surfaced upward extension including outwardly extending surfaces and vertically extending surfaces connecting the same; the periphery of the upper of said outwardly extending surfaces. ing disposed inwardly of the inner side of the outwardly extendlng surface below the same 7. A piston for internal combustion engines comprising an extension of substantially step formation on thehead thereof having transversely extendmg step surfaces and vertically extending riser surfaces there the piston head, and locking.

between; said extension tapering towards the top thereof, and said transverse surfaces consisting of spiral convolutions decreasing in height and increasing in magnitude towards the base thereof.

8. A piston for internal combustion engines comprising a taperin extension thereon of substantially step formation having transversely extending step surfaces and verticall extending riser surfaces therebetween 0 less height than the width of said transverse surfaces; said transverse and vertically extending surfaces consisting of spiral comvolutions decreasing in height and increasing in magnitude towards the base thereof.

9. A piston for internal combustion engines comprising an extension thereon of substantially step formation decreasing in cross-sectional area towards the to thereof, and having a substantially large base compared to the height of the extension; the transverse step surfaces thereof consisting of spiral convolutions decreasing in height and increasing in magnitude towards the base thereof, and the riser surfaces thereof being disposed substantially vertical.

10. A piston for internal combustion engines comprising an extension thereon of substantially step formation decreasing in cross-sectional area towards the top thereof; the transverse step surfaces thereof consisting of spiral convolutions, and the riser surfaces thereof connecting the same forming therewith angles each at least substantially as great as a right angle.

11. A piston for internal combustionengines comprising an upward extension thereon of substantially step formation decreasing in cross-sectional area towards the top thereof, and having a substantially flat central portion, and transverse step surfaces consisting of spiral convolutions surrounding said central portion and extending downwardly therefrom and outwardly towards the periphery of the piston.

12. A piston for internal combustion engines com rising an extension thereon of substantial y step formation decreasing in cross-sectional area towards the top thereof, and terminating in a substantially flat horizontal surface; the transverse step surfaces of the extension consisting of spiral convolutions surrounding said flat horizontal surface and extending downwardly therefrom and outwardly towards the periphery of the piston.

13. A piston for internal combustion engines comprising an extension thereon of substantially step formation decreasing in cross-sectional area towards the top thereof and terminating in a substantially flat horizontal central surface; the transverse step surfaces of the extension consisting of spiral convolutions disposed about said central surface and decreasing inheight and increasing in size towards the base thereof, and the riser surfaces thereof bein disposed substantially vertically and having a height less than the width of said transverse step surfaces and forming substantially right angles therewith.

14. An internal combustion engine comprising a cylinder, and a piston therein having a head of step formation increasing in height from the periphery thereof towards the center thereof, and ignition means in.

said combustion chamber disposed in oflset relation to said piston in the top center position thereof and facing the riser surfaces of said step formation.

15. An internal combustion engineconiprisinia cylinder, and a piston therein having a ead of helicoidal step formation increasing in height from the periphery thereof towards the center thereof, and ignition means in said combustion chamber disposed in offset relation to said piston in the top center position thereof and facing the riser surfaces of said step formation.

In testimony whereof, I have signed my name hereto.

ARLINGTON MOORE.

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