US2574934A

US2574934A - Internal-combustion engine

Info

Publication number: US2574934A
Application number: US151398A
Authority: US
Inventors: John C Perry
Original assignee: Perry Products Inc
Current assignee: Perry Products Inc
Priority date: 1950-03-23
Filing date: 1950-03-23
Publication date: 1951-11-13
Anticipated expiration: 1968-11-13

Description

Nov. 13, 1951 J. c. PERRY 2,574,934

' INTERNAL--COMBUSTICN ENGINE Filed March 25, 1950 2 SHEETS-SHEET 1 lllllllllllllHl 'llfi'lllllllllllllllllllllll" IN VEN TOR.

L/O' C/ e r/j/ ATTORNEY$- Nov. 13, 1951 J. c. PERRY 2,574,934

INTERNAL-COMBUSTION ENGINE Filed March 23, 1950 2 SHEETS-Si-IEET 2 INVENTOR. whgz 6? erry ATTORNEYS.

Patented Nov. 13, 1951 INTERNAL-COMBUSTION ENGINE John 0. Perry, Cranston, R. I., assignor, by direct and mesne assignments, to Perry Products, Inc., a corporation of Rhode Island Application March 23, 1950, Serial No. 151,398

This invention relates to improvements in an internal combustion engine.

It is well recognized that some fuel is not burned and thus lost during the operation of an internal combustion engine. The ignition of the gaseous charges is arranged so as to start combustion as the crank approaches near upper dead center and further combustion of the gaseous charges occurs on the downward movement of the piston, which piston movement reduces the maximum compressionof the gaseous charges by the enlargement of the combustion chamber. Because of the rapid descent and the relative short stroke provided in the present internal combustion high-speed engine, the fuel does not have sufficient time for a complete effective burning thereof, with a resulting waste of the fuel.

The general object of the invention is to improve on internal combustion engine constructions so that a more complete effective combustion of the gaseous charges thereof will be had with an increased fuel efficiency.

A more specific. object of the invention is to construct internal combustion engine so that greater combustion of the gaseous charge will be developed at the maximum compression thereof.

Another object of this invention is to construct an internal combustion engine so that a major portion of the forces developed by the combustion of the gaseous charge will be appliedagainst the crank when thesame has passed a substantial distance beyond upper dead center and is at a point of greater leverage.

Another object of this invention i t provide a connection between the power piston and the engine crank so constructed as to provide fora substantial period in the piston movement at the position of maximum compression thereof.

With these and other objects in view, the invention consists of certain novel features of construction, a will be more fully described and particularly pointed out in the appended claims.

In the accompanying drawings:

Figure l is a central sectional view of a fragmental portion of an internal combustion engine 8 Claims. (Cl. 309- 17) closure associated with the member shown in Figure, 4;

Figure 6 is a sectional view of the piston show in Figure l with the connecting rod attached thereto showing one relative position between the connecting rod and piston;

Figure 7 is a similar view showing another rela tive position between the connecting rod and piston; and

Figure 8 is also a similar view showing a still further relative position between connecting rod and, piston. i

In carrying out my invention, I provide a shifting pivotal connection between the piston and its connecting rod. The connection is such that when the crank is advanced to a predetermined point before upper dead center, the pistonwill have moved to its uppermost position of travel and be at maximum compression. At this position of the crank, the connecting rod will extend from the crank into engagement with the piston at a location thereon to be in direct line with the centers of the crank and crankshaft bearing, so that a force applied against the piston tending to move it and the force applied against the piston opposing such movement will result in-no tendency to move said piston. 1

At each further advance of the crank in the same direction, the pivotal point of engagement of the connecting rod with the piston will shift along a guiding under surface of the piston adistance so as to maintain the point of engagement of the connecting rod in line with the crank and crankshaft centers so as to neutralize the forces acting against the piston as above stated. This condition will be maintained as the crank is advanced from said predetermined point beforedead center to a like distance past dead center. The said shifting of. the point of engagement of the connecting rod with the piston will also change the effective length of the connecting rod between its point of engagement with the piston and the crank center such as to maintain the piston rela-: tively stationary at the said maximum compression for the said predetermined distance of angular movement of the crank, thus providing for a dwell in piston movement for a predetermined angular movementv of crank at maximum piston compression. I

The gaseous chargesv introduced, into the combustion chamber of the engine in a well-known manner is ignited in ausual manner such as by use of a spark plug and is timed so that combustion will start at substantially the instant of maximum. compression. of the gaseous charges.

The dwell in piston movement will provide suflicient time for nearly complete combustion of the said gaseous charges at maximum compression thereof, thus providing for a more effective burning of the fuel to build up a force to be exerted at maximum violent pressure against the crank.

Referringto the drawings for a more detailed description of the invention, l designates generally an internal combustion engine only enough of which is shown to illustrate the invention, it being understood that the same is provided with the usual valve controlled ports and other usual necessary elements to make the same operative. The engine may be of the so-called four cycle type or the two cycle type and comprises a cylinder block ll secured to a crankcase 12, the block having a usual bore l3, the upper end portion of which provides a combustion chamber [-4 which is closed by a cylinder head 15. A power piston l 6 is disposed within the bore l3 and is connected to a crankshaft I! having a crank arm [8 with a bearing I9 which is embraced by a connecting rod 23 which extends from the said crank into engagement with the power piston I6.

In the present embodiment of the invention, the upper end portion of the said connecting rod 23 is formed T-shape providing similar arm portions 2|, 2 2, the

free end extremities

24, 25 of which are semi-circular in shape with a straight surface 26 extending tangentially from the

said portions

24, 25. As previously stated, the connecting rod is attached to the piston l6 by means of a shifting pivotal connection guided in its movement by a guiding under surface of the piston. For manufacturing reasons the said guiding under surface is provided by means of a, guide bearing member designated generally 21 (see Figure 4). The member 21 is of a general rectangular inverted U-shape providing a recess in which is received the upper end portion or head of the connecting-rod 20. The upper wall 28 of the recess has a cam surface 29 which is engageable by the straight surface 26 of the connecting rod and the side walls 33 and 3| have

curved guide surfaces

32, 33, respectively, which converge toward each other; The end portions 24, are slidably related to the

surfaces

32, 33 by means of

shoes

34, 34 which are positioned between each 21; the said

end portions

24, 25 and the surfaces Each shoe 34, 34' is of a similar construction and may be made of a material having great wear resistance qualities. The side of the shoes in contact with

surfaces

32, 33 extends on the same curvature as that of the

said surfaces

32, 33 and each shoe has a recess 35 in which the

end portions

24, 25 are pivotally mounted, the walls of the recesses 35 extending on the same curvature as that of the

end portions

24, 25. Lateral movement of the connecting rod 20 relative to the member 2'! is prevented by cover plates 3'! positioned on either side of the frame 21 and secured thereto by suitable fastenings which may be of any suitable kind such as, by way of example, rivets 38.

The assembly of the connecting rod and member 21 designated generally '39 (Fig. 2) is inserted centrally within the piston I6 which has oppositely diametrically disposed recesses 40 (see Fig. 3) in which are received the side marginal edges 39 of the said assembly 39. Any appropriate manner of securing the assembly 39 to the piston may be employed. In the present instance, as by way of example, cap screws 4| extend through proper openings in the piston skirt and threadcd-- 4 1y engage the sides of the frame '21. It will, of course, be evident that the head of such screws will be sunk below the outer surface of the piston.

In the reciprocal movement of the piston I 6. the upper end portion of the connecting rod of the piston oscillates from either end portion 24. 25 as a pivot depending upon the direction of travel of the piston I6 and the opposite end portion moves along its associated guide surface. The

said surfaces

32, 33 are each on a curvature of radius equal to the distance between the centers of the semi-circular surfaces of the

end portions

24, 25, plus the radius of one of the

end portions

24, 25 and the thickness of a shoe 34 at a point in line with the said centers of the said semi-circular surfaces (see Figs. 4 and 6). The said

surfaces

32, 33 are described from diametrically opposite points 42 with which the centers of the radius of the recess of the shoes 34, 34' coincide, when the said shoes are at their uppermost position within the member 21. The cam 29 for all practical purposes may be made an approximate chord of a circle, the depth b of which is equal to the depth 0 of a chord taken on the path of movement of the crank by a line intersecting a predetermined point 43 on said path before nor mal dead center position 45 of the crank and a point 44 on the said path at an equal distance past the said normal dead center 45 (see Fig. 6). The curve of the cam 29 is depended upon'the length of the connecting rod, the size of the path of the crank and the length of piston dwell desired. With these factors established the curve may be plotted by those familiar in such art to produce the results hereinafter to be described.

In the operation of the engine thus far described, assuming the gaseous charge to have been drawn into the combustion chamber l4 in a usual manner, the piston I6 is advanced to compress said charge. At the predetermined point 43 in the path 46 of movement of the crank [8 in the direction of arrow 47 (see Fig. 6) the crank center 48 will be at d angular distance from upper dead center position 45 5f the crank l8 and the upper end portion'of the con necting rod 20 will have assumed the position shown in Fig. 6. At this position of crank H3, the piston l6 will have been advanced to its uppermost limit of travel and be at maximum compression. The shoe 34 also will have been moved to the upper limit of the guide wall 32 and the junction of the surface 26 at the beginning of the curved surface of the end 24 will be in contact with the curved guide surface 29. This point of engagement between connecting rod 20 and piston l6 will be in a direct line with the centers of the crank I8 and crankshaft l1. Any force applied against the piston tending to move the same and the force on the piston opposin such movement will result in no tendency to move the piston I 6.

Upon further movement of the crank IS in the same direction toward dead center 45, the upper end portion of the connecting rod 20 will oscillate about the center of the recess of the shoe 34 in a counter-clockwise direction, as seen in Figure 6, and the surface 26 will rock along the cam 29 to assume a position of engagement on said cam 29 such that the said point of engagement will also be in direct line with the centersof the bearings of the crank and crankshaft, thus neutralizing any forces tending to move the piston [6. The rocking of the surface 26 on the guide surface 29 will have the effect of changin the-effective length, bi ths-connectin god. $01535 to meintain the piston stationary "betweenwthe normal upper dead center" 45. .The effectivelength cftheconnecting rodmrwillibe at a; maximum whenthe crank i8. is at thepredetermined- Wi li-4.3 and will decreasev in efiectivelen the surface 26 is rocked on cam 29 tab at a minirnum eifective length when at the mid point of engagement between the surface 26 and cam 28 and which oint of engagement is in direct line passing thro gh he crank b aring-abnorma dead center 45 and the center of. the Crankshaft I! (see Fig. 1) The effective length of fthe connecting ro'dwill change in the reversed order that is; it will lengthen astheprank I8 ismolled past the said normal. dead center 45 a ain be at maximum effective length when the crank center 48 has moved passed dead center 45 a distance equal to the distance between the said predetermined point 43 and the said normal dead center 45 or at point 44 on the path 46, (see Fig. 7). At this position of the connecting rod 29, the end portion 25 will have been moved to its uppermost position as shown in Fig. 7. The end portion 25 will be at a position diametricallyopposite to the position of end portion 24' 'as shown in Fig.- 6, and-the point of engagement between the piston and connecting rod will be in direct line with the center of the crank and crankshaft bearing. Further movement of the crank passed point 44 will position the connecting rod at an angular position to permit the expansion force of combustion to act against the piston to move the crank about the crankshaft center. However, as the connecting rod 20 is now being oscillated about the center of the recess in shoe 34' at the uppermost position thereof on surface 33, the effective lengthof the connecting rod 20 tends to increase until the crank has reached a position shown in Fig. 8. Consequently, the initial downward movement of the piston is slowed or in other words the downward movement of the piston is not in proportion to the angular movement of the crank between point 44 and the position of the crank as shown in Fig. 8. Therefore, a still larger portion of the forces of combustion may act against the piston at a point of greater leverage.

On the downward movement of the piston 16 at substantially the crank position shown in Figure 8, the upper end portion of the connecting rod will reverse its direction of oscillation and the surface 26 will be moved to rock on the cam 29 as the piston approaches lower dead center of crank. position. As above pointed out, the rocking of the surface 26 on the cam 29 has the effect of changing the effective length of the connecting rod and this effective length decreases as the contacting surface 26 and cam 29 approach their mid point of engagement. Therefore, as the surface 26 rocks on the cam 29 at the reversal of direction of oscillation of the connecting rod about the shoe 34 as a pivot the effective length of the connecting rod decreases to be at a minimum effective length when the crank is at lower dead center position and the point of engagement of the surface 26 with the cam 29 is at their mid point of engagement. As the crank I8 passes lower dead center position the effective length of connecting rod will change in the reverse order. Thus, nov dwell in piston movement will be had at the lower extreme of its movement other than that usually provided by the usual piston rod connection.

the end of the'rocking motioniof the. surfaceilli on, 2 9. when the; piston is i at its. lower position, the. shoe. 3.4 will have.- been moved to the upper limit-of its. travel along the. guide 5111';- face 32, to complete. the up-strok'e of the iston lt to the position shown ,in Fig. 6 to again fol! low the cycle of movement above described The ignition of the gaseous charges are timed so that combustion will take place near the in stant of maximum compression. However, the timing-of the ignition may be arranged, so as. to suitv engine characteristic to produce the most efficl'ency-of operation thereof, and the timing of: the ignition maybe such that combustion may be in theprocess asthe piston It. moves intoimax-imumcompression.

It may now be apparent that I have disclosed an internal combustion engine construction, particularly a piston connecting rod connection in which its effective length changes in a manner to provide a dwell of substantial duration in piston movement at maximum compression thereof so as to permit a more complete effective combustion of the gaseous charges at maximum compression and the resulting forces of which are released at maximum violent pressure to act against the engine piston. It will also be apparent that the structure is such that no piston dwell is had at the reversal of travel thereof at the end of its power stroke.

I claim:

1. In an internal combustion engine, a cylinder, a piston therein, a crankshaft having main bearings and crank bearings, a connecting rod connected to said crank bearing and provided with an enlarged head located Within the piston, said piston having a recess providing a sur face lateral of the piston axis and converging surfaces lengthwise of said axis to confine the head within the piston while permitting rocking thereof in a plane at right angles to the crankshaft bearing.

2. In an internal combustion engine as in claim 1 wherein at one position of the rod at an angle to the piston axis the point of contact of said head with said lateral surface and the center of the crank bearing and center of the main bearing are in line.

3. In an internal combustion engine as in claim 1 wherein at all positions at the to stroke of the piston the point of contact of said head with said lateral surface and the center of the crank bearing and center of the main bearing are in line.

4. In an internal combustion engine as in claim 1 wherein at all positions of the top stroke of the piston within a predetermined range of angular movement of the crank the point of contact of said head with said lateral surface and the center of the crank bearing and center of the main bearing are in line.

5. In an internal combustion engine, a cylinder, a piston therein, a crankshaft having a main bearing and crank bearing, a connecting rod connected to said crank bearing and extending therefrom with the upper portion thereof disposed within said piston, said piston having a cam guiding surface therein extending laterally thereof and engaged by said connecting rod to change the effective length thereof during a predetermined angular movement of said" crank hearing at near top center position of said crank bearing to provide a dwell period in piston movement during the said predetermined angular movement of said crank bearing.

- 6. In an internal combustion engine, a 'cylinder'," a piston therein, acrankshaft having a main bearing and crank bearing, a connecting rod connected to said crank bearing and extending therefrom with the upper portion thereof disposed within said piston and mounted thereon for oscillating motion relative thereto, a stationary cam guiding surface on said piston extending laterally of said crankshaft and rock-. ably engageable by said connecting rod to change the effective length of said connecting rod during a predetermined angular movement of said crank hearing at near top center position of said crank bearing to provide a dwell period in piston movement during the said predetermined angular movement of said crank bearing.

7. In an internal combustion engine as in claim 6 wherein at all positions of engagement of said connecting rod with said cam at the upper position of said piston, the point of com tact of said rod with said cam and centers 0 said bearings are in line.

8. In an internal combustion engine as in claim 6 wherein said rod has a T-shaped head, the upper surface of which rockably engages said cam.

JOHN C. PERRY.

REFERENCES CITED The following references are of record in file of this patent:

UNITED STATES PATENTS Number