US2445715A

US2445715A - Crankcase compression, two-cycle engine

Info

Publication number: US2445715A
Application number: US709127A
Authority: US
Inventors: Jarvis S Jennings
Original assignee: HOOF PRODUCTS Co
Current assignee: HOOF PRODUCTS Co
Priority date: 1946-11-12
Filing date: 1946-11-12
Publication date: 1948-07-20
Anticipated expiration: 1965-07-20

Description

July 20, 1948*.

Filed Nov. 12, 1946 .1. s. JENNINGS 2,445,715

CRANKCASE COMPRESSION, TWO-CYCLE ENGINE I5 Sheets-Sheet 1 2.; 38 a will I4 14 .f/ I 4 37 3 1 (farms S. ciennzn ys July 20, 1948. J. SFJE NNINGS CRANKCASE COMPRESSION, TWO-CYCLE ENGINE 3 Sheets-Sheet 2 Filed Nov. 12, 1946 Emma 3mm Jarvzs Sclnn in ys ,MA'W

July 20, 1948. ENNI 2,445,715

CRANKCASE COMPRESSION, TWO-CYCLE ENGINE Filed Nov. 12, 1946 3 Sheets-Sheet 3 elliliieze.

avy/27:"

Jarvis xlmrzil zys Patented July 20, 1948 CRANKCASE COMPRESSION, TWO-CYCLE ENG Jarvis S. Jennings, Chicago, Ill., assignor to Hooi Products Company, Chicago, 111., a corporation of Illinois Application November 12, 1946, Serial No. 709,127

11 Claims.

This invention has to do with internal combustion engines.

As here shown it is developed with a two-cycle type of engine, primarily designed for model airplanes. It will be understood, however, that features adaptable to types of engines and airplanes other than the speciflc example here shown are not restricted to the particular adaptation herein disclosed.

More particularly the present disclosure relates to the make-up of the engine cylinder and crank case, which are so developed that they form a multi-part construction preferably made up of an integrally formed open-topped cylinder jacket and open-sided crank case member, independent side plates being provided to enclose the crank case and cylinder jacket members. Such independently formed side plates are so constructed that not only do they effectively close the crank case to form a suitable compression chamber, but also provide fuel feed passages of small crosssectional area from the chamber to the combustion cylinder which is associated with the Jacket, eliminating the necessity of coring or drilling such passages.

A further feature of the invention is the provision of an independent readily detachable closed-top combustion cylinder member, insertable in the open-topped cylinder jacket member, which latter may be cast integrally with the crank case member, said closed-top cylinder combustion member being formed to receive the piston; the spark plug, and finned to give proper cooling areas. Suitable inlet and exhaust passages are provided in the cylinder walls, these passages being so disposed relative to one another that minimum interference between feed of fresh fuel and burnt gases results, and proper scavenging is secured.

Another object is the provision of a piston which will control inlet and exhaust ports and direct the fuel flow, and the make-up of which is such as to provide a convenient and novel coupling of piston; pitman, and crank-shaft.

Valve mechanism for controlling fuel flow from a fuel supply to the compression chamber of the crank case, is pivotally mounted on a side plate. and so coupled to the crank-shaft as to give a simple, readily formed, and assembled construction. The mounting of the valve on the side plate is such that trapping of fuel in the valve and possible explosion of such trapped fuel is avoided, the entire volume of fuel passing to the compression chamber.

These and other objects will be set forth more 2 in detail in the description which follows, reference being had to the accompanying drawings, in which:

Figure 1 is a view in side elevation of an engine embodying one physical form of the invention.

Figure 2 is a view in vertical section of the engine shown in Figure 1.

Figure 3 is a view in horizontal section substantially on the line 3-3, Fig. 1, looking in the direction of the arrows.

Figure 4 is a view in vertical section substantially on the line 4-4, Fig. 2, looking in the direction of the arrows.

Figure 5 is an enlarged vertical section of the closed-top cylinder member.

Figure 6 is an enlarged horizontal section on substantially the line $--8 of Fig. 5.

Figure 7 is a view in perspective of a side plate, showing a fuel passage; the valve seat and mounting on the side plate, and the valve.

Figure 8 is a view in perspective to show the top of the jacket.

Figure 9 is a view of the piston, partly in section, showing the fuel directing recesses, the wrist pin, and spring rings for attaching the pitman.

Figure 10 is a view in perspective to show the crank pin key for engaging the fuel control valve.

Figure 11 is a perspective view of the wrist pin for the piston and the clamping rings.

Figure 12 is a detail view of the bolt for securing the combustion cylinder and jacket together.

The parts shown in the drawings will be designated by numbers, the same numbers indicating the same parts in the different views.

Referring to the jacket cylinder and crank case, these as here shown, are made up of four pieces. The crank case ill and an open-topped outer cylinder jacket I l are preferably of integral formation and the crank case in has open sides. A closed top combustion cylinder l2 telescopes in the jacket II and forms the combustion chamber, as best shown in Figs. 2 and 4. This cylinder may be formed relatively thin, as it is reinforced by the jacket I I, and its upper part at top and side will be provided with cooling fins ii. The fins l2 will be deeply cut close to the cylinder wall and top so as to ensure rapid radiation through the thin cylinder wall and eiiicient cooling. The thin sleeve-like cylinder I! will be of material having highresistance so as to withstand the usual internal pressures.

The cylinder i2 is secured to the jacket II by means of a horizontal flange II projecting outwardly from the wall of cylinder member 12,

said flange being provided with bayonet, slots l4, through which pass headed bolts I5, four being here shown, which are threaded into suitable bolt holes l6 formed in the outer cylinder jacket H just above the exhaust outlets I4 which extend outwardly from jacket II. The outlets ll are preferably oval in cross section to reduce their outer dimension and yet give sufficient exhaust area, and are ribbed or finned for cooling. This connection between jacket II and member I2 provides for easy assembling and disassem 'bling of the crank case, jacket, piston, and combustion cylinder member, so that the parts may be initially put together, taken down for inspection or repair, and reassembled with a minimum of effort; The assemblage is such, however, that a secure and strong structure results which will stand up under the work to be performed and a fluid tight construction is assured.

The open-sidedcrank case Ill and jacket II are closed by side plates I'I fitted in place and held by screws-or other suitable fastening means. Screws I8 engage the upper ends of the plates H with the jacket II, while through bolts I9 traversing spacing sleeves between side plates I1, hold the lower cylindrical portions of the side plate members I! together. This arrangement effectively completes the make-up of the engine housing and provides a sealed compression chamber and combustion cylinder.

The side plates I1 have open recesses on their inner faces to form fuel passages. 2i of small cross sectional area leading from the crank case upwardly. The lower ends of passages 2i communicate with inlet openings 22 to admit fuel from .the crank case compression chamber. At the upper ends of passages 2|, fuel delivering ports 23 are provided through jacket II and the thin wall of the telescoped cylinder member I2 to permit delivery of fuel to the explosion chamher. With this construction it will be seen that side plates II, when assembled with crank case I 3; cylinder jacket H, and combustion cylinder member I2, provide a complete engine structure. Further, by forming the recesses 2| on the faces of plates H to provide, when assembled with the other parts, suitable fuel feed passages, all coring or drilling of feed passages is avoided. The crank case; cylinder jacket, and side plates can be cast or formed in any suitable manner, and readily assembled to complete the unit.

. Disposed substantially at right angles to the opposed fuel delivery ports 23 are exhaust ports fuel and the relation of the inlet and exhaust ports effectively completes scavenging and charging without undue mixing of burnt products and fresh fuel, and loss of part of the charge through the exhaust ports.

The piston is made up of thin stamped members. The outer member 25 constituting the piston proper and fitting the cylinder, the inner member 26 being secured by riveting or in any other suitable manner to member 25 and engaged with the pitman 21 by a hollow wrist pin 28 suitably held in place by spring rings 28. This combination gives a light but rigid position which may be readily stamped up from sheet metal.

24, slightly above the fuel inlets 23, so that they will be uncovered by the piston just in advance of the uncovering of fuel inlets 23, which exhaust ports 24 deliver to the exhaust vpipes I4 extending outwardly from the cylinder.

With this construction, as arranged in the twocycle engine shown, the upward thrust of the piston draws fuel into the crank case and compresses the charge above the piston for ignition and the power stroke. Explosion of the charge in the combustion cylinder effects the power stroke, forcing .the piston downwardly and first opening the exhaust ports 24. scavenging will begin immediately the exhaust ports are opened, the exhaust ports being uncovered in advance of the inlet ports 23. Fresh fuel entering ports 23 will be so directed upwardly from the piston, presently to be described, that the fuel jets from ports 23 will follow the vertical wall of cylinder I2 to the fiat cylinder top and will then spread inwardly and turn back centrally of the cylinder toward the piston. This action of the incoming To effect proper fuel distribution, the top of the piston member 25 is provided with recesses 29 which preferalbly are closed at their ends and may be partially formed, as shown in Figure '9, in projections 29. These recesses coincide with the fuel inlets 23 and will accurately define and direct jets of fuel coming from the inlets upwardly in the combustion chamber. These f-uel jets will follow well defined paths along the wall of the cylinder and meet at the top of the chamber where they combine, spread, and turn downwardly to form the explosive charge, which charge is ignited by any suitable ignition member such as spark plug 30.

Fuel is supplied to the compression chamber of crank case ID, by an inlet 3| from any suitable carbureting devices (not shown) and inlet 3| is controlled by valve 32 pivoted on a side plate I1. Valve 32 has an arc-shaped port 34 which, as valve 32 revolves, opens the inlet 3| and permits fuel to be drawn into the compression space of the crank case. Movement of the valve 32 is so timed and related to the valve operating means that it closes and opens at points appreciably past dead centers for the up and down limits for the piston stroke. Valve 32 is coupled to the crank pin 35 projecting from the crank disc, crank pin 35 being here shown as integral with crank disk 36, and of hollow construction so as to lighten it while still maintaining the requisite strength. The outer open end pin 35 is .milled oil to form a projection or key 31 which engages a notch 38 in the rim of valve 32 when the parts are assembled. This gives an easily formed, efficient valve drive with a minimum of parts and of light construction. Lightening of the parts, without sacrificing strength 01' efficiency is of great importance in the development of airplane engines. This is particularly true of engines for model plane construction where weight must be reduced as much as possible to permit maximum fuel load capacity. The crank and propeller shaft 39 are preferably drilled, as shown, for lightness. Valve 32 has -a pivot pin 40 of considerable length engaging the side plate II in order to give it'an extended bearing in the side plate and ensure exactness of rotary movement in opening and closing fuel inlet 3i. The piston and crank pin will be coupled by a pitman of any usual or suitable construction.

The valve 32 takes its bearing on a seat 4| made up of the raised outer edge of the side plate and the centrally disposed seating member, as shown in Fig. 7, this bearing surface being of such shape and size as to provide a proper surface to support valve 32 in its rotary movements and yet reduce frictional contact. This raised seat 4| holds the valve 32 slightly spaced from the body surface of side plate ll, but as this interspace I2 is in open communication with the recesses forming the inlet passages 2|, no

trapping of fuel coming from inlet 3| behind valve 32 can occur.

A timer '1, is conventionally shown, but as this forms no part of the present invention and may be of any suitable type, no detailed description of it is necessary.

This disclosure is of one particular embodiment of the invention, but it is to be understood that such variations from what is here shown as are within the skill of the mechanic and are comprehended by the appended claims, are to be regarded as within the range of the invention.

I claim:

1. An internal combustion engine comprising a cylinder jacket member and crank case, said jacket having an open top and inlet and exhaust ports; a closed-top combustion cylinder engaged with said jacket and having inlet and exhaust ports registering with the ports in said jacket; detachable side plates having fuel feeding passages on their inner faces leading from a compression chamber in said crank case to said combustion cylinder; a crank shaft coupled to said piston; means for supplying fuel to the compression chamber in said crank case, and a valve actuated from said crank shaft to open and close the port from said fuel supply to the crank case compression chamber.

2. The invention as defined in claim 1 in which the crank case has open sides and the detachable side plates close said open sides of the crank case.

3. The invention as defined in claim 1 in which the cylinder jacket member and the open-sided crank case are integral.

4. The invention as defined in claim 1 in which the combustion cylinder is telescopically engaged with said jacket.

5. The invention as defined in claim 1 in which the combustion cylinder is telescopically engaged interiorly of said jacket.

6. The invention as defined in claim 1 in which the combustion cylinder is provided with means for detachably connecting it tosaid jacket.

7. An internal combustion engine comprising I a cylinder jacket member; an open-sided crank case having inlet and exhaust ports; a closedfaces leading from a compression chamber in said crank case to said combustion cylinder, a piston controlling the inlet and outlet ports, a crank shaft coupled to said piston, means for supplying fuel to a compression chamber in said crank case, and a valve actuated from said crank shaft to open and 'close the port from said fuel supply means to the crank case compression chamber.

8. The invention as definedin claim 7 in which the means detachably connecting said combustion cylinder and said jacket comprises a bayonet joint.

9. An internal combustion engine comprising a combustion chamber, a piston in said chamber, a crank case having a compression chamber and an open side, a crank shaft, a crank pin on said shaft, a pitman coupling said pin and piston,a detachable side plate having a fuel feeding recess on its inner face and a fuel inlet closing the open side of said crank case and connecting the compression chamber of said crank case with said combustion chamber, and a rotary valve actuated by said crank pin mounted on said side plate to control the fuel inlet.

10. A detachable side plate for closing an opensided compression chamber of an internal combustion engine having a fuel inlet and a fuel feeding recess on its inner face. I

11. A detachable side plate for closing an opensided compression chamber of an internal combustion engine having a fuel inlet, a fuel receiving recess and a fuel feeding recess on its inner face, and a rotary inlet control valve pivotally mounted on the side plate in the fuel receiving .mavrs s. JENNINGS.

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

UNITED STATES PATENTS France 1907