US2727499A - Two-cycle engine - Google Patents

Description

Dec. 20, 1955 e. s. WALLER 2,727,499

TWOCYCLE ENGINE Filed June 26, 1953 3 Sheets-Sheet l JNVENTOR.

ewy c5. WaZ/ex Dec. 20, 1955 G. s. WALLER TWO-CYCLE ENGINE 3 Sheets-Sheet 2 Filed June 26, 1953 Dec. 20, 1955 G. s. WALLER 2,727,499

TWO-CYCLE ENGINE Filed June 26, 1953 3 Sheets-Sheet 3 660476 c5 Wa/Zwr Barfl g ATTORNEY $7? 7 INVENTOR United States Patent @fiice 2,727,499 Patented Dec. 20, 1955 TWO-CYCLE ENGINE George S. Waller, Manchester, Conn. Application June 26, 1953, Serial No. 364,321 3 Claims. (Cl. 123-59) This invention relates to improvements in an internal combustion engine.

The invention is more particularly concerned with a two cycle internal combustion engine and a primary object of the invention is to provide an improved crank shaft assembly for metering the fuel charges to the pistons of the engine.

A further object of the invention is to provide an improved cylinder block and cooperating cylinder head together with pistons of a novel form and which cooperate with the head in a manner to substantially increase the efliciency of the engine.

A further and highly important object of the invention is to provide a two cycle internal combustion engine wherein charges of fuel are metered out by a single member rotatable with the crank shaft and such metering consisting in first delivering a charge of fuel to the crank case and Within a cylinder and cooperating piston communicating therewith for a super charging action by retraction of the piston, and thereafter delivering the thus compressed fuel charge to the cylinder above the piston for further compression thereby immediately preceding ignition thereof.

A still further object of the invention is to provide a two cycle internal combustion engine which is relatively simple in construction, highly eflicient in operation and which is capable of manufacture at relatively low cost.

Other objects and advantages of the invention will become apparent in the course of the following detailed description, taken in connection with the accompanying drawings, wherein:

Figure l is a vertically sectional view substantially axially of the crank shaft and showing the invention in accordance with a preferred structural embodiment thereof.

Figure 2 is a side elevational view of the improved crank shaft as observed from the left thereof in Figure 1.

Figure 3 is a horizontal sectional view in the plane of line 3-3 on Figure 2.

Figure 4 is a vertical axial section of one of the improved pistons utilized in the present improved internal combustion engine.

Figure 5 is a side elevational view of the piston as observed from the right of Figure 4.

Figure 6 is a top plan view of the improved piston, and

Figure 7 is a side elevational View thereof as observed from the left of Figures 4 and 6.

Referring now in detail to the drawings, and more particularly Figure 1, 10 designates a crank case, on the top of which is suitably secured a cylinder block 11, and a cylinder head 12 is suitably secured on the top of the cylinder block 11 with an intervening gasket 13.

The improved crank shaft 14 shown in Figure l and in more detail in Figures 2 and 3 comprises opposite end crank shaft cylindrical sections 15 and 16 respectively projecting axially upwardly and downwardly from disks 17 and 18 and being rigid therewith.

A pair of crank pins 19 and 20 rigidly interconnect the disks 17 and 18 with an intermediate fuel metering cylindrical member 21, the pins 19 and 20 being disposed equidistantly from the axis of the crank shaft and having their axes diametrically spaced a distance equal to the length of piston strokes.

The cylindrical shaft sections 15 and 16 are rotatably supported in bearing assemblies 22 and 23 supported in bearing caps 24 and 25 respectively.

The adjacent faces of disks 17 and 18 and the cylindrical member 21 together with the cylindrical wall in the crank case provide fuel receiving chambers 26 and 27 to which fuel is alternately admitted by means of the cylindrical member 21 and for such purpose the said member is constructed as follows.

Recesses 27 and 29 are provided in the member 21 with their opposite side walls in equally spaced relation to planes including the axes of shaft sections 15 and 16 and the crank pins 19 and 20.

As is more clearly indicated in Figure l, the recesses 28 and 29 open through opposite side walls of the member 21 and also open through the peripheral wall thereof to an extent less than the axial thickness of the member.

The opposed Walls 3% and 31 of the crank case 10 are provided with openings 32 and 33 with which said recesses 28 and 29 are simultaneously in communication when the pistons are at opposite ends of their strokes.

Carbureted fuel is admitted through opening 33 by means of a suitable manifold adapted for connection with wall 31 and in communication with the opening 33.

A pair of cylinders 34 and 35 are rigidly supported in the cylinder block 11 as well as the cylinder head 13 and which cylinders have their outer walls spaced from the side walls of the cylinder block and said outer walls at adjacent points thereof are spaced a distance equal to the width of opening 32 in the top wall 30. A pair of pistons 36 and 37 are operatively connected to the respective crank pins 19 and 29 by piston rods 38 and 39 respectively, which extend through fuel admitting openings 30a in wall 30.

The improved pistons are an important factor in the invention and are specially constructed in a manner as is more clearly illustrated in Figures 4 to 7.

Referring now to those figures in which piston 36 is shown in detail, same comprises a cylinder wall engageable skirt 4% provided with the usual ring receiving grooves 41 as well as the piston pin receiving bosses 42.

The important feature of the piston is the form of the head thereof and which comprises a horizontal relatively narrow arcuate top wall 43 substantially in the plane of the upper end of the skirt 40, a vertical wall 44 including a central major arcuate portion 45 convex relative to the center of the piston and minor arcuate portions 46 which are concave relative to the center of the piston. The piston head further includes a horizontal wall 47, one edge of which is at its junction with wall 44 and whose opposite edge is in a straight line 48 parallel with but in slightly spaced relation to an axial plane of the piston. The remainder of the piston head is in the form of a top wall 49 which is upwardly concave and which extends from line 48 into the plane of the top of the piston skirt 40 As is shown in Figure l, the upper ends of the cylinders 34 and 35 are in the cylinder head 12 and are closed except for tapped spark plug receiving openings 50 and a portion of said upper ends are of arcuate formation as indicated at 51 for cooperation with the arcuate piston wall portion 4-9. It is to be particularly noted that the cylinder block and cylinder head includes a heat absorbing water chamber 11a.

It is to be further noted that the cylinders 34 and 35 are provided with diametrically opposed inner and outer 3 ports 52 and 53 immediately below the water chamber. The ports 52 are for fuel intake while ports 53 are for exhaust and the said ports are preferably in multiple.

As shown in Figure 1, the crank pins are in a vertical plane including the axis of the crank shaft 14 with pistons retracted and piston 37 projected. The recess 23 is in communication with fuel chamber 26 and the opening 32 in wall 30 while the recess 29 is in communication with fuel chamber 27 and the fuel admission opening 33 in wall 31.

In this position fuel is being admitted to the chamber 27 which chamber is out of communication with opening 32 by the solid portion of the cylindrical member 21. Also in this position fuel previously admitted to chamber 26 is being admitted through recess 28 and opening 32 into the cylinder head 11.

It is to be particularly noted that in this position of parts, opening 52 in cylinder 35 is closed by the associated piston 37 while the corresponding opening 52 in cylinder 34 is open for the admission of fuel into cylinder 34 above its associated piston 36.

The reverse of the above occurs when the cylindrical member 21 rotates through an angle of 180.

The openings 32 and 33 are each elongated lengthwise of the crank case in keeping with the substantial width of the recesses 28 and 29 in the fuel metering member 21 and the cylinder block 11 is open all the way around the cylinders 34 and 35.

Since the operation is identical with each piston 36 and 37 and the recesses 28 and 29 serve the respective cylinders 36 and 37, the operation will be discussed in connection with cylinder 37 which is shown at the outer limit of its stroke.

In this position, the recess 29 intercommunicates the fuel opening 33 and the crankcase fuel chamber 27 with a resulting flow of fuel into chamber 27 and thence through opening and into the cylinder and hollow piston 37. The suction action of the piston assures a full crankcase supply of fuel.

Upon initial retraction of the piston 37, the recess 29 will have moved out of communication with opening 33 whereby the substantially large mass charge of fuel within chamber 27 and cylinder 35 will be highly compressed upon retraction of the piston 37 The piston on its retraction or inward stroke will continue to compress the fuel charge until it has moved to a point where the outer end of the skirt 40 is just about to begin the opening of port 52 and at which time the recess 29 will have moved'to a position to admit the compressed fuel-through the opening 32 and into the cylinder block 11. As the piston continues to retract and clear the port 52 the pre-compressed charge of fuel will rush through the port 52 and into the cylinder 35 between the piston head and the closed end of the cylinder. At this point, it is to be observed that the formations 43, 44, v

and 46 on the piston 37 imparts a movement to the fuel generally axially of the cylinder but along the wall thereof adjacent the ports 52.

Upon outward movement of the piston, the ports 52 will be closed and the pre-compressed charge of fuel will be further compressed until the piston reaches its outer limit when the highly compressed charge of fuel will be ignited by a timed plug in opening 50.

During ignition of the compressed fuel charge, the burned gases will be deflected by the wall 49 of the piston 37 such that upon final retraction thereof such gases will exhaust through openings 53 and escape from the open cylinder block through the opening 54 to atmosphere. The escape of the burned gases will be aided by the succeeding charges of pre-compressed fuel entering the ports 52.

In this connection, it will be observed that piston 36 is in a position where pre-compressed fuel is entering ports 52 while the exhaust gases are passing outwardly through opening 53 and which exhaust gases will pass out through the opening 54.

It is to be particularly observed that the pre-compressed fuel charges are admitted into adjacent sides of the cylinders 34 and 35 while the exhaust gases pass out at opposite sides of the cylinders, that is cylinder 34 exhausts upwardly while cylinder 35 exhausts downwardly.

Having set forth my invention in accordance with a preferred structural embodiment thereof, what I claim and desire to secure by U. S. Letters Patent is:

1. A two cycle internal combustion engine comprising a crank case, a cylinder block including a cylinder communicating with the crank case and having a closed outer end, the said cylinder block comprising a wall surrounding the cylinder and providing a chamber therein, the crank case including a base wall having a fuel inlet opening therein, the crank case further including a wall adjacent the cylinder block having an opening therein for communication between the crank case and said chamber in the cylinder block, a crank shaft rotatably journalled in said crank case, a piston in said cylinder operatively connected to said crank shaft, diametrically opposed ports in said cylinder providing for fuel admission to the cylinder, and exhaust of burned gases therefrom, a cylindrical member fixed to said crank shaft having a recess therein opening through the periphery and one side thereof, the recess in one angular position of the member providing communication between said fuel inlet opening and said crankcase for admission of a charge of fuel into the crank case, cylinder and piston, said member upon continued rotation thereof closing said fuel inlet opening and said piston on its retracting stroke compressing the said charge of fuel within the crank case, said recess upon continued rotation of said member providing communication between said crank case and said chamber for admission of the compressed fuel charge into the latter, and said piston upon continued retraction clearing said fuel inlet ports for admission of said compressed fuel charge into said cylinder outwardly of the head of the piston for further compression upon outward movement of the piston preliminary to the ignition of the charge of compressed fuel.

2. The structure according to claim 1, wherein said cylinder block is provided with a second cylinder, and said crank shaft cylindrical member having a second recess therein diametrically opposed to said first recess and opening through the periphery of the member and the opposite side thereof for controlling the flow of fuel to said second cylinder, said second cylinder being provided with diametrically opposed fuel admission and gas exhaust ports and a piston in said second cylinder operatively connected to the crank shaft in relation to the first piston.

3. The structure according to claim 2, wherein the fuel admission ports are disposed in adjacent sides of said cylinders, and the gas exhaust ports are disposed in opposed sides of said cylinders, the said cylinderblock being open about the cylinders, and a gas exhaust opening in the lower wall of said cylinder block, common to the exhaust ports of both cylinders.

References Cited in the file of this patent UNITED STATES PATENTS 2,103,564 Tanner Dec. 28, 1937 2,118,761 Johnson May 24, 1938- 2,154,975 Dufour Apr. 18, 1939 2,246,446 Kylen June 17, 1941 2,394,970 Aronson Feb. 19, 1946 2,512,739 Duncan June 27, 1950

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