US1734867A - Internal-combustion engine - Google Patents

Description

Nov. 5, 1929 D. J. MARTIN INTERNAL CGMBUSTION ENGINE Filed Nov. 16. 1927 2 Sheets-Sheet INVENTOR ,U JTJMarfim BY ATTORNEYS WITNESSES D. JKMARTIN 11,734,867

INTERNAL CQMBUSTION ENGINE Fil'ed Nov. L6, 1927 2 Sheets-Sheet 2 Nov. 5, 1929.

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DOUGLAS 3. MARTIN, OE NEW YORK, N. Y., -ASSIGI\TOR T MARTIN MOTORS, INQ, GE NEW YORK, N, Y., A CORFORATION OF DELAWARE INTERNAL-COMBUSTION ENGINE Application filed November 16, 1927. Serial No. 233,670.

is connected, is in the most effective posi-' tion.

7 A further object is to' provide an engine of the character stated in which the crank arm of the drive shaft to which the working piston is connected is disposed within a sector centering on 90 to an eccentric on the crank shaft, the strap of said eccentric being to the auxiliary piston whereby the action of the eccentric and the auxiliary piston has a lag behind the movement of the working piston.

Thisjengine is adapted for high or low speeds and has many advantages over the other types of engine, all of which will be more fully hereinafter described and pointed out in the claim. I

In the accompanying drawings- Figure 1 is a view in longitudinal section.

of my improved engine, showing the pistons in approximate position for ignition of the mixture;

Figure 2 is a fragmentary view taken at right angles to Figure-1 through the crank case and a portion of the engine;

' Figures 3, 4, 5 and 6 are diagrammatic views showing the various positions of the pistons in the cylinder during the power and 'suction stroke;

Figure 7 is a diagram'illustrating the movements and operation of the pistons.

I shall first describe the engine illustrated and later set forth the operation and advantages attained by the engine.

1 represents an engine cylinder having a closed head 2 and at its lower end secured to a crank case 3 in which a crank shaft 4 18 mounted. For convenience of description I shall refer to the upper and lower ends of the engine but it is of course to be understood that the engine may function in other positions than in a vertical one and that this language is employed for convenience in describing the engine.

5 and 6 represent inlet and exhaust valves in head and 7 is a spark plug or other means for ignition. In the casing 1 a Working piston 8 is provided and connected by a connectlng rod or link 9 with a crank arm 10 on shaft 4.

Thisworking piston 8 reciprocates within an auxlhary piston 11, the latter reciprocating freely in the cylinder 1. The auxiliary piston 11 is connected at its lower end, and at opposite sides, by links or connecting rods r 12 with eccentric straps 13 on eccentrics 14 of the crank shaft 4. w

The crank arm 10 and the eccentrics 14 are disposed within a sector centering on an angle of approximately 90 to each other, and this is an important phase of my invention that will hereinafter be enlarged upon.

The arrangement of pistons and their mountings in the cylinder is capable of mod ilication, but I have illustrated the auxiliary piston as having an annular chamber 15 externally thereof in which inlet and exhaust openings 16 and 17 are provided for the passage of a cooling medium.

Furthermore, I may provide around the auxiliary piston a spiral or other web 17 to strengthen the piston and guide the same in the cylinder.

The lower end of the auxiliary piston is preferably provided with one or more keyways 18 receiving keys 19 in the cylinder 1 so as per ends of the workingpistonS and the auxiliary piston 11 are the same, but this is of course capable of modification, in accordance 'with the results desired.

In this particular case I desire that the auxiliary piston may be either of the same area as the working piston or has a movement which will displace a volume equal to the displacement of the working piston end, so that as the working piston moves past dead center, which is a downward movement, the auxiliary piston will moveupwardly and maintain a volumetric balance. If the the auxiliary piston displaces a larger volume than the working piston the result will-be a super-compression or post-compression which may also be accomplished' by a greater movement of the auxiliary piston and this variation in movement is of course controlled by the throw of the co- 2 centrics.

To explain the operation of the engine, attention is called to the-diagram Figure 7 and also to Figures 3, 4:, 5 and 6 which illustrate diflerent ositions of the pistons.

at the left indicates a complete revolution of the crank shaft, the capital letters indicating the sectors, of movement of the crank arm 10, and the small letters the movement of the eecentrics. The horizontal lines extending to the right of the circular diagram indicate the linear movement of the working piston in a com lete reciprocation and the small diagram at t e upper, right-handportion of Figure 86 7 illustrates the linear movement of the auxiliary piston registering with a small circular diagram indicating the movement of the eccentrics.

Also at the central portion of the right- 49 hand circular diagram (Figure 7) thehorizontal lines indicate the linear movement of the auxiliary piston as brought about by the turning movement of the eccentrics.

the extreme of. its upper movement with the crank arm at dead center, and it shows when inthis position that the auxiliary piston is substantially parallel to the working face of the working piston. I

5o Fi re 4 illustrates the approximate firing positlon, and it will be noted that as the crank arm passes over dead center the working piston '8 moves downwardly at the same time the auxiliary piston moves upwardly, thus maintaining a volumetric balance in the cylinder. v v

' Figure 5 shows the working piston 8 moving downwardly on its power stroke and it will be noted that during a portion of the downward movement of the working piston the auxiliary piston moves upwardly and then follows downwardly with the stroke of the working piston.

However, it will be noted that the linear movement of the auxiliary piston is very short Inthe 'agram (Figure'?) the bisected circle as compared with the movement of the working piston due of course to the throw of the eccentrics as compared with the throw of the crank arm, but these movements of the working and auxiliary pistons are exactly timed in accordance with the angular position of the crank arm relative to the eccentrics which will now be explained, reference being had more particularly to the diagram in Figure 7 The circle indicating the movement of the crank arm and eccentric in Figure? is, for convenience of description, divlded into sectors of twenty-two and a'half degrees each, and the diagram indicates an engine with a pressure balanced through twenty-two and a halt degrees.

While the working piston crank turns through the first sector A, the eccentric shown at a 90 lag also turns through a sector of the same size, indicated by a. The, diagram shows that the working piston falls a distance, indicated by A, and the auxiliary piston rises a distance, indicated by a. A and a are equal and the eccentric circuit may be so designed that this equal fall and rise will:

hold good to any desired point of balance.

At top dead center, the working piston and the auxiliary piston are side by side. As the working piston fallsthrough the distance indicated by A, the auxiliary piston rises through an equal distance, indicated by the character a. 1

As the crank arm turns through the sector .B the working piston falls a distance, indicated by B', and the eccentric turns through the sector b and rises a much lesser distance than the working piston, as indicated at I).

These relative movements can be followed on the diagram through the medium of the letters, the capital letters indicating the sectors through which the crank arm moves and thesmall letters indicate the sectors through which theeccentrics move, the primed capital Figure 3 illustrates the working piston at letters indicating the linear movement of the working piston and the'primed small letters of the volumetric balance and ignition'then' following 1s expansion, continuing) through the measures 13, C, D, E' and Fand exhaust through G, H. Y

It is of course to be understood that the tlmlng of the exhaust may be varied so that -it may be lengthened or shortened, but in any event this exhaust takes place while this pis ton is at or near its lowest sector. 1 i

The capital letters I, J K, L, M, N, O, P, mdicate'the movement of the piston on its scavenging stroke as well as on its compression stroke, and thls complete reciprocation is of course repeated in a four-cycle engine to draw in the charge and compressit,

as above explained.

In the above description of my invention I apply the termauxiliary piston to the part 11 and as this piston functions as acompressi'on member, forming a partaffixed to a tube or sleeve it may also be termed a compression piston, and these terms are used indiscriminately as the part 11 is in reality both a'piston, a sleeve and a compression member.

An engine such as above described and op erated in the manner stated has many advantages some which may be enumerated as follows:

There will be no loss of compression while the piston is passing over dead center.

The compression may either be maintained or increased to super-compression or postcompression in ,accorda-nce with the throw of the eccentric.

The work of compression and super-compression is divided between the crank arm and the eccentrics, the working piston and the auxiliary piston both moving toward the head of the cylinder for compression and for maintenance of compression. This enables the cutting down of the weight of the individual parts. i

The working piston moves up rapidly and attains the first stage of compression and when it'has arrived at a certain pressure the auxiliary piston or compression piston moves up and increases this pressure to any desired amount'in accordance 'With the movements imparted to the pistons. Y

The wide number of adjustments of angle, eccentric throw, and of length of eccentric connecting rod, permit of any desired adjustment and timing of the pressure balance or pressure boosting function of the tubular compression piston.

The invention, as shown, achieves a volumetric balance at both ends of the stroke when the two pistons are moving in different directions during the period .of' equal lifts for equal angles.

It permits of a lowerpower stroke, and gives more time for the functioning of the valves, near top and bottom dead center.

When the Working piston is at dead center and beginsto fall in the cylinder, the tubular compression balance piston rises and balances the pressure above the falling working piston to any desired point. In the diagram this is'shown to a point of twenty-two anda half degrees beyond dead center. Then i the balancepiston continues up at a slow rate 'until it reaches the top of its travel, the working piston, in the meantime, falling rapidly. v

By'increasing the throw of the eccentrics,

'greatercompression may be obtained. or the Attention is called to the relatively large range of compression pressures attainable by a relatively small movement of the tubular compression piston after the working piston has come to dead center.

A very small increased movement causes a corresponding decrease in volume, but at the point where this small decrease in volume means a great increase in pressure. That is, after the working piston has passed dead center (the point of maximum compression in ordinary gas engines) by the rela tively large angle between the crank and the eccentric, and by adjusting the eccentric throw, and the position and area of the tubular compression piston, I can attain any desired increase in compression.

A further and very important new feature is the fact that the up and down movement of the tubular compression piston is much less (about one-half) of the up and down movement as required in my original patent to'achieve the required balance on an angle of thirty-six degrees, more or less.

I have referred to the operating parts as a crank arm and eccentric, and I would have it distinctly understood that these terms are used in the broadest possible sense to include any mechanical means or mechanism which Will function for the purpose, as, for example, the eccentric might constitute a crank arm and other expedients might be resorted to, and I do not wish to be limited to such terminology employed in the specification or the claim.

, While I have illustrated what I believe to be a preferred embodiment of my invention, it is obvious various changes and alterations might be made in the general form of the parts described without departing from my invention and hence I do not limit myself to the precise details set forth but consider myself at liberty to make such changes and alterations as fairly fall within the spirit and scope of the appended claim.

I claim:

In an internal combustion engine, the combination with a cylinder and an auxiliary piston in the cylinder, of a working piston within the auxiliary piston, said auxiliary piston having a displacement within the cylinder such that during the period in which the working piston moves from the top dead centre to a predetermined ignition position, the auxiliary piston is given an inward displacement through a portion of its stroke wherein its spee auxiliary plston and its displacement maintains a predetermined compression condition. Signed at New York, in the county of New York and State of New York, this 14th day of November, A. D. 1927.

DOUGLAS J. MARTIN.

d is greatest, the arrangementbeing such that the product of the area of thev

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