US2622573A

US2622573A - Opposed piston internal-combustion engine

Info

Publication number: US2622573A
Application number: US162720A
Authority: US
Inventors: William M Nichols
Original assignee: American Locomotive Co
Current assignee: American Locomotive Co
Priority date: 1950-05-18
Filing date: 1950-05-18
Publication date: 1952-12-23
Anticipated expiration: 1969-12-23

Description

Dec, 23, 1952 w. M. NICHOLS OPPOSED PISTON INTERNAL-COMBUSTION ENGINE Filed May 18, 1950 FIG-3 FIG 2 mvzmon W/LL/AM M. N/CHDLS %cuwa,

ATTORN EY Patented Dec. 23, 1952 OPPOSED PISTON INTERNAL-COMBUSTION ENGINE William M. Nichols, Schenectady, N. Y., assignor to American Locomotive Company, New York, N. Y., a corporation of New York Application May 18, 1950, Serial No. 162,720

Claims.

This invention relates to compression-ignition internal combustion engines, and particularly to such engines employing multi-cylinder opposed pistons operating on a two-stroke cycle to drive a single crankshaft.

A disadvantage inherent in the conventional engine of the type described is that the crankshaft requires two throws for each cylinder. Such a construction necessitates a width between the center lines of the cylinders which in many uses of the engine is extremely inconvenient and results in an engine whose dimensions create formidable problems. To offset this dimensional difficulty, some designers have limited the journal and crankbearing lengths, as well as crank web thicknesses, and in some cases have reduced the number of main bearings. Such skimping, however, is generally considered to be poor practice. In spite of the shortcomings described, this type of engine has had a wide increase in use, especially in the small sizes where the crankshaft limitations are not too serious as a practical proposition. The inherent good balance in units having ,a small number of cylinders and the simplicity of valveless design have to a great extent offset the disadvantages.

Applicant has designed an engine of the described type, which has as its principal object to retain theadvantages of good balance but to overcome the crankshaft dimensional disadvantages so that it may be used on large constructions such as a diesel-electric locomotive where space requirements are of utmost importance. Applicants further object is to provide an engine which includes multiples of two cylinders, each pair of cylinders having an X-beam or equivalent rocker arm construction on one end and a parallel rocker arm construction on the other end thereby to actuate pairs of connecting rods having either fork and blade or articulate extremities for connection with the cranks. By such a construction, applicant has provided an engine in which one piston of the pair functioning on their power strokes will, through suitable linkage, actuate one crank and the opposed piston in the same cylinder will actuate the other crank. While this pair of pistons is thus operating on their power strokes, the other pair of pistons are driven on their compression strokes by the cranks. Stated otherwise, the two pistons in each pair of cylinders which are moving in the same direction, say to the right, one outwardly in one cylinder on its power stroke and the other inwardly in the other cylinder on its compression stroke,

are connected by their associated linkages to the same crank. The other two pistons, moving to the left, function correspondingly. The pistons functioning on their power strokes thus simultaneously impart motion to the crankshaft and drive the other pistons inwardly on their compression strokes. The masses of the elements involved can be so designedthat at full load the crank and main bearings will have to carry only the tangential effort loads, and this will result in low bearing friction andextremely long bearing life. The results in space-saving will be obvious from an inspection of the drawmgs.

In the drawings, Fig. l is an elevation of the engine of the invention in which the cylinder block, one pair of pistons, and the crankshaft are shown in section; Fig. 2 is an end view of the engine, on a larger scale than Fig. 1, showing the parallel rocker arm construction; Fig. 3 is a view of the other end of the engine, on the same scale as Fig. 2, showing the cross-over construction of the rocker arms; Fig. 4 is a fragment of the crankshaft showing the two cranks of the engine connected to rods of the fork and blade type; and Fig. 5 is a detail showing a construction of the extremities of one pair of connecting rods having an articulated instead of a fork and blade construction with the crankshaft.

In the drawings, open-ended cylinder block I0 is a casting, although it may, if desired, be fabricated as a heavy steel plate weldment. The block carries a pair of cylinders II and [2 in a horizontal bank. In cylinder II is arranged a pair of opposed pistons 13 and I4, and in cylinder 12 is arranged a similar pair of such pistons I5 and I6. Fuel combustion takes place between each pair of pistons preferably on compression ignition principles so that the direction of the power stroke of the pistons is outwardly of the cylinders. No description is felt necessary of the means of supplying air and fuel to the combustion chambers or of the means of ignition or of the means of cooling and lubricating the engine, as they are well known and form no part of the invention as such.

Pistons l3, l4, l5, and 16 are conventionally connected by wrist pins I! to corresponding connecting rods I311, Ma, lEa, and I6a, the outer extremities of which are pivoted by means of pins 18 to corresponding vertically disposed rocker arms [3b, Mb, 15b, and I622. The construction and arrangement of these two pairs of rocker arms are important as they form essential features of the invention. Rocker arms I41) and IE1), which are arranged at one end of the block (the left end as viewed in Fig. l) are parallel (see Fig. 2) and are mounted approximately midway their lengths upon a shaft is fixedly secured in the parallel extensions or lugs 2| integrally formed upon or separately fabricated and secured to block It. At their lower extremities, rocker arms Mb and I6!) are pivoted by means of pins 22 to lower connecting rods I40 and I60 respectively. Such lower rods I40 and Itc are provided at their other extremities with a blade Md and fork I6d respectively for connection with the

cranks

23 and 24 of crankshaft 25. This crankshaft, as seen in Figs. 2 and 3, is arranged transversely to the vertical planes PP and FF passing through the longitudinal center lines C of cylinders II and I2 and the axis AA of the crankshaft extends normally to such vertical planes. Crankshaft 25 is journalled in the downwardly projecting central extension 25a of the block and its axis lies in thevertical plane RR transversely bisecting the working cylinders I I and I2 as seen in Fig. 1.

The rocker arms I31) and I5b at the other end of the block (the right end as viewed in Fig. 1) are arranged in cross-over relation. Rocker arm I3b' (see Fig. 3) is an integral part of a rocker unit whose central member is a hollow hub 26 mounted to oscillate on a shaft 21 rigidly mounted in the parallel extensions or lugs 28 of the block. Such rocker unit also includes a dependent rocker arm I36, the lower extremity of which is connected by one of the pins 22 to the lower connecting rod I3c. Rocker arms I31) and" I3e are parallel and extend upwardly and downwardly from the opposite ends of the hub as an oifset bell crank. Rocker arm I5b is similarly an integral part of a second rocker unit which likewise has a central hollow hub 29 which oscillates on a shaft 3| rigidly mounted in extensions 28; This second unit also has a dependent rocker arm I5e whose lower extremity is connected by one of'the pins 22 to lower connecting rod I50; It will be apparent, of course, that equivalent transmission means, such asgearing, could be arranged to transmit the motion in a crossover relation in the same manner as is done by the rocker mechanism illustrated. Lower connecting rods I and I50 are formed at their inner extremities with a blade I311 and a fork I5d respectively for connection with the

crank bearings

24 and 23 respectively. The longitudinal center lines GG of rods I40 and I (see Fig. 4) pass through the center of crank pin bearing 32, and the longitudinal center lines I-II-I of rods I30 and I60 pass through the center of crankpin bearing 33. Such center lines are in the vertical planes PP and PP respectively which pass through the longitudinal center lines of the cylinders.

The'arrangement of the rocker mechanism at the right end of the block thus provides a crossover transmission whereby piston I5 is linked to crank-23 and piston I3 is linked to crank 24. As previously explained, the left end rocker mechanism is constructed so that piston I4 is linked to crank 23 and piston I6 is linked to crank 24. It thus can be seen that upon the power stroke in cylinder I2, piston It will rotate crank 24 and its opposed piston I5 will at the same time rotate crank 23. As piston It drives crank 24, lower connecting rod I30 and its linkage will actuate piston I3 inwardly on its compression stroke, and at the same time, piston 4 I5 drives crank 23 to actuate connecting rod Ida and its linkage to move piston I4 inwardly on its compression stroke. Obviously when ignition and consequent expansion takes place in cylinder II; a corresponding sequence will take place in that cylinder so that pistons I3 and 54 will rotate the crankshaft and compress the working fiuid between pistons I5 and IG.

It should be noted from an inspection of Fig. 1 that the axes of shafts I9, 3|, and 2'! are in the same horizontal plane so that the tensions of the pistons on their power strokes are balanced.

In Fig. 5 is shown an alternate construction of means to connect the connecting rods to the cranks. Instead of a fork or blade, as previously described, two of the rods may be formed with caps 35 secured to the rod shanks 36 by bolts 31, the caps having short bifurcation 38 formed with aligned apertures 39 for the reception of a pin M. The ends of coacting rods are provided with apertures which are aligned with apertures 39, and the two pairs of rods and then secured together by pin 4|. By such a construction the two rods are disposed in alignment adapted to engage the

crank bearings

32 and 33.

While there have been hereinbefore described approved embodimentsof the invention, it will be understood'that many and various changes and modifications in form, arrangement of parts and details of construction thereof maybe made without departing from the spirit and scope of the present invention, and that all such changes and modifications as fall within thescope of the appended claims are contemplated as a part of this invention.

What I claim is:

1. An internal combustion engine comprising a block, first and second cylinders disposed'in parallel relation therein, a pair of opposed pistons in each of the cylinders, means to actuate each pair of pistons on their power strokes in timed relation to each other, a crankshaft'having its axis disposed in a plane parallel to'the plane joining the longitudinal center lines of the cylinders, such crankshaft having first andsec- 0nd cranks thereon, linkage means between one piston in the first cylinder and the first crank, linkage means parallel to the first linkage means connecting one piston in the second cylinder and the second crank, linkage means between the opposed piston in the first cylinder and the second crank, and linkage means crossing over the last mentioned linkage means and connecting the opposed piston in' the second cylinder and the first crank.

2. An internal combustion engine comprising a block; first and second-cylinders arranged in parallel relation therein; a pair of-opposed pistons in each of the cylinders; means to actuate each pair of pistons on their power strokes in timed relation to each other; a crankshaft having its axis disposed in aplane parallel to the plane joining the longitudinal center lines of the cylinders; a-pair of cranks on the crankshaft spaced a distance apart equal to the distance between the longitudinal center lines of the cylinders; a pair of linkages arranged in parallel at one end of the block, one of the=linkages connecting one piston in the first cylinder and one crank and the other linkage connecting one piston in the second cylinder and the othercrank; and a pair of linkages arrangedm cross-over relation at the other endofthe block, one of the linkages connecting the opposed piston in the firstcylinder with said other crank, and the other linkage connecting the opposed piston in the second cylinder with said one crank.

3. An internal combustion engine comprising a block; first and second cylinders arranged in parallel relation therein; a pair of opposed pistons in each of the cylinders; means to actuate each pair of opposed pistons on their power strokes in timed relation to each other; a crankshaft having its axis disposed in a plane parallel to the plane joining the longitudinal center line of the cylinders; a pair of cranks on the crankshaft; a connecting rod bearing on each of the pair of cranks, the centers of the bearings rotating in vertical planes passing through the longitudinal center lines of the cylinders; linkage means at one end of the block connecting one piston in the first cylinder and the crank vertically therebelow; linkage means at the same end of the block arranged parallel to the first linkage means and connecting one piston in the second cylinder and the crank vertically therebelow; linkage means at the other end of the block connecting the opposed piston in the first cylinder and the crank vertically below the second cylinder; and linkage means at said other end of the block crossing over the last mentioned linkage means at the other end of the block and connecting the opposed piston in the second cylinder and the crank vertically below the first cylinder.

4. An internal combustion engine comprising a block; first and second cylinders disposed in parallel relation therein; a pair of opposed pistons in each of the cylinders; means to actuate each pair of pistons on their power strokes in timed relation to each other; a crankshaft having its axis disposed in a plane parallel to the plane joining the longitudinal center lines of the cylinders; such crankshaft having first and second cranks; a pin-bearing on each crank for a connecting red, the longitudinal center of each pin rotating in a vertical plane passing through the longitudinal center line of one of the cylinders; linkage means at one end of the block connecting one piston in the first cylinder and the crank vertically therebelow; linkage means at the same end of the block disposed in a zone parallel to the zone of the first linkage and connecting one piston in the second cylinder with the crank vertically therebelow, said second piston being disposed at the opposite relative end of its cylinder as the first mentioned piston is disposed in its cylinder; linkage means at the other end of the block connecting the opposed piston in the first cylinder to the crank vertically below the second cylinder; and linkage means at said other end of the block crossing over the last mentioned linkage and connecting the opposed piston in the second cylinder and the crank vertically below the first cylinder.

5. An internal combustion engine comprising a block; first and second cylinders spaced in parallel relation in the block; a pair of opposed pistons in each of the cylinders; means to actuate each pair of pistons on their power strokes in timed relation to each other; a crankshaft having its axis disposed beneath the block and arranged in a plane parallel to the plane joining the longitudinal center lines of the cylinders; first and second cranks on the crankshaft; connecting rod hearings on each crank, the centers of which rotate in vertical planes passing through the longitudinal center lines of the cylinders;

rocker unit having an arm oscillated by the opposed piston of the first cylinder, a hub, and an arm parallel to the first arm to actuate the crank; and linkage means pivoted to said other end of the block connecting the opposed piston of the second cylinder to the crank vertically below. the

first cylinder, said linkage including a rocker unit having an arm parallel to the first arm to actuate the crank.

6. An internal combustion engine, according to claim 5, in which the pivot points for the linkages on both ends of the block are disposed in the same horizontal plane.

7. An internal combustion engine comprising a block; first and second cylinders disposed in parallel relation therein; a pair of opposed pistons in each of the cylinders; means to actuate each pair of pistons on their power strokes in timed relation to each other; a crankshaft having its axis disposed in a plane parallel to the plane joining the longitudinal center lines of the cylinders, such crankshaft having first and second cranks thereon; linkage means between one piston in the first cylinder and the first crank including a connecting rod engaging the crank; linkage means between one piston in the second cylinder and the second crank, including a connecting rod engaging the second crank, both linkage means being at one end of the block with the connecting rods arranged in parallel relation; linkage means between the opposed piston in the first cylinder and the second crank, such means including an upper connecting rod operating in the vertical plane passing through the longitudinal center line of the first cylinder, a lower connecting rod operating in the vertical plane passing through the longitudinal center line of the second cylinder, and a rocker device connectin such connecting rods; and linkage means between the opposed piston in the second cylinder and the first crank, including an upper connecting rod operating in the vertical plane passing through the longitudinal center line of the second cylinder, a lower connecting rod operating in the vertical plane passing through the longitudinal center line of the first cylinder, and a rocker device connecting such connecting rods.

8. An internal combustion engine comprising a block, an even number of cylinders disposed in parallel relation therein, a pair of opposed pistons in each of the cylinders, means to actuate each pair of pistons on their power strokes in timed relation to each other, a crankshaft having its axis disposed in a plane parallel to the plane joining the longitudinal center lines of the cylinders, cranks on the crankshaft corresponding in number to the number of cylinders, and means for each pair of cylinders connecting one piston in each cylinder with a crank, and means connecting the other piston in each cylinder with the adjacent crank.

9. An internal combustion engine comprising a block, an even number of cylinders disposed in parallel relation therein, a pair of opposed pistons in each of the cylinders, means to actuate each 'pairzofipistons on their power strokes in timed relation to eachother; acrankshaft having its axis disposed in a plane parallel to the plane joining the longitudinal center lines of the cylinders, cranks on the, crankshaft correspondingin number to the number of cylinders, a connecting rod bearing on each of the cranks, the centers of the'bearings rotating in vertical-planes passing through the longitudinal center lines of the cylinders, and transmission meansfor each pair of cylinders connecting one pistonin-eachcylinderhwitha crank, and means-connecting the other piston in each cylinder withthe adjacent crank.

10.- An internal combustion engine comprising ablock, first and second cylinders arranged in parallel relation therein, a pair of opposed pistons ineach of the cylinders, means to actuate each pairof pistons on their power strokes in timed relation to each other, a crankshaft having its axisdisposedin a plane parallel to the plane joining the longitudinal center lines of the cylinders, a single pair of cranks on the crankshaft for the cylinders spaced a distanceapart equal to the distance between the longitudinal center lines of the cylinders, and transmission means connecting one piston in thefirstcylinden with the first crank and-the opposed piston in the first cylinder with the, second crank-and connecting one piston in the second cylinder withthe second crank and the opposed piston in the second cylinder with the first crank.

WILLIAM-M. NICHOLS.

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

UNITED STATES PATENTS Number Name Date 1,662,740 Dennison Mar. 13; 1928 2,067,049 Goldberg Jan. 5, 1937 2,099,371 Olds Nov. 16, 1937 2,112,829. Colburn Apr. 5, 1938 FOREIGN PATENTS Number Country Date 475,448 Germany 0f-1929 627,089 Germany of 1936 785,711 France ofl935