US2399276A

US2399276A - Variable compression ratio internalcombustion engine

Info

Publication number: US2399276A
Application number: US498293A
Authority: US
Inventors: Herbert J Kratzer
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-08-12
Filing date: 1943-08-12
Publication date: 1946-04-30
Anticipated expiration: 1963-04-30

Description

n INVENTOR QT. Krul ABY f" ?atente repa- 3, l

assar'zc CORESSN RATIO ENTEBNAL- This invention relates to internal combustion engines and pertains particularly to the compression phase of the operation of the engine,

and in which, the principal object is to provide the conventional, multi-cylindered internal combustion engine with simple and reliable means to greatly improve the over all thermal eiiiciency through the entire'range of throttle operation.

A further object is to provide the engine with means to decrease the combustion chamber volume of respective cylinders, in approximately the same ratio that the absolute pressure in intake manifold decreases below the prevailing atmospheric pressure.

A still further object is to provide simple means permitting the adjustment of the'degree of compression of respective individual cylinders oi an engine to the exact compression pressure desired.

Another object is to provide for the automatic positioning or' the mechanism so that a mean compression ratio will prevail as therengine is started, but which becomes fully eiective after a minimum time of the engines operation.

Yet another object is to employ the degree of vacuum in the plurality of cylinders of an engine, greatly augmented by the simultaneous decrease in the intensity oi expansion pressures, to

supply the motive force necessary to'actuate the mechanism, and thereby to increase the compression ratio, resulting in an approximate constant absolute compression pressure at all times oi engine operation.

Another further object is to provide the firing chambers with resiliently actuated means to automatically vary the size oi' the chambers with respect to the momentary torque loads of the engine.

Other objects and advantages will appear as this description progresses and by referencetc the drawing, in which- Figure i is a plan elevation of an eight-in-line, cylindered internal combustion engine, with the invention applied thereto and forming part thereoi.

Figure 2 is an enlarged fragmentary vertical.

vsectional elevation, taken approximatelyon the line 2--2 ci Fig. l.,

Referring by numerals-to the drawing, t desig nates each of two aumliary blocks used in this instance of showing and describing the invenl tion, as applied to a conventional four-cycle intornai combustion engine, said' blocks being used in place of the cylinder head blocks of the conventional engine.

Each block t is provided with its plurality of cylinders ai, each of which when the blocks are I mounted and secured in place on the engine cylinder block or blocks 5, alining with respective i6, said lever it also being keyed to the shaft ll.

The remaining links 9 of respective pistons i are connected at their upper ends to respective short levers il, keyed to the shaft H. j

The long end of the lever l2 is provided on its free end with an adjustable pusher pin i8 in en gagementwth the depression is of a saddle 2t on the upper end of an expansion coil spring 2l, the lower end of said spring being seated in a saddle 2i within an inverted piston 23 which is reciprocally mounted in c, cylinder 2t, supported from one of the blocks Upper and lower adjustable stops 25 and 2e' respectively of ay supporting bracket 2l are provided for limiting the swinging travel of the lever l2, said bracket being mounted on one of the blocks Si.

Provision is made for maintaining a'n oil body in the space 2t beneath the piston 23 in the cylinder 2d, through the oil line 2t from the oiling system (not shown) of the engine, whenthe engine is operating.

In practicing the invention, when the engine is stopped, the spring 2l will force the lever i2 upwardly against the stop 2t, and consequently, all of the pistons l will be lnoved to maximum lowered positions in the cylinders t by the rocking or the shaft il, thereby decreasing the size.

of the tiring chambers to points ofgreatest compression ratio, as would be required to approximate designed compression at idling operation'or the engine, and at which position the adjustable stop 25 is nxed.

Simultaneous with the spring 2i forcing the' lever i2 against the stop 25 the spring will force the piston 23 down in the cylinder 21.3 as `the oil therebeneath leaks back to the crank case through the oil line 29, and the free length of the spring will be approximately attained when the piston 23 seats against the 'bottom wall of the cylinder 2t, as shown in dotted lines in Fig. 2.

The instant the engine is started, the' compression pressure against the pistons 1 will rock the shaft II `and cause the spring end of the lever I2'to bear against the unloaded spring 2l and start to compress it. Before any of the cylinders have iired, the lever I2 will have moved the approximate half of its normal operative range of travel in compressing the spring to its initial operative tension, and upon succeeding revolutions of the engine crank-shaft with normal ignition of all of the-cylinders 6, the lever I2 will be completely moved against the bottom stop 26,.

which limits the degree of outward movement of the pistons 1, to positions of least compressionr ratio as required to provide the desired degree of compression, permitted by the fuel used. As the engine is started to idling, the lever I2 will be returned to a position determined by the initial spring tension.'

The lever I5`of the dash-pot I6, being connected to the torque shaft Il, dampens out the inter-cyclic rocking movement impulses of .the shaft Il, so that lthe mean average of the sum of the impulses-will be required to be counterbalanced by the tension of the spring 2l. The action of the tension of the spring 2l and the dash-pot I6, on the rocking of the shaft Il, results in no movement of the shaft Il and the pistons 1 linked Lthereto, unless a change in en# gine torque occurs.

During the initial idling period of the engine, the lubricating oil pump of the engine, will force Aoil up under the piston 23, thus gradually moving the partly compressed spring 2| outwardly until the piston 23 reaches the stop-ring 3U, at the outer end of the cylinder 24, and at which time the lever I2 will be in a position near the upper stop 25, because the initial spring pressure at the spring end of the lever, will just balance the combined opposed turning eort on the shaft I I, consisting of the algebraic sum of the gas pressures of all of the pistons 1 on their respective short lever connections with the shaft II. Thus, as the engine was idling, the oil pressure from the oil line 29.in raising the spring piston 23, also raised the spring end of the lever I 2 which caused the 'cylinder head pistons 1 to be moved to positions of minimum combustion chamber volume in respective firing chambers 8 for providing a maximum compression ratio for eiiicieni; idling operation of theengine.

When the engine throttle (not shown) is opened.

be effective in causing the spring 2| to move the pistons 1 inwardly. Any throttling effect, incidental or intentional, will obviously cause a decrease in the sum of gas pressures on the pistons 1, with a proportionate decrease in the torque output of the engine, and the spring tension will then relocate the lever I2 to just balance the smaller forces on the pistons 1 and in so doing, relocate said pistons to positions vof greater compression ratio. Thus, since the engine torque output is approximately directly proportional to forces on the pistons 1, it is obvious that the automatically selected compression ratio will vary inversely proportionate to the torque output of the engine.

By utilizing the varying gas pressures as well as the varying vacuums in therespective operating cylinders, an extremely simple, reliable and eiiicient mechanism is provided, whereby the corrective forces are large compared to the small inherent friction of the simple linkages used. Due therefore, to the simple mechanism disclosed, automatically selected, varying compression ratios, will instantaneously and reliably remain adjusted to the highest values as indicated for best thermal efliciency, and should border-line knocking occur, the greatly increased combustion chamber pressures in effecting an enlargement of the combustion chamber volumes, inherently removes the primary cause.

The adjustable links 9 permit exact equalization of individual cylinder compression, and the entire engine compression range can be adjusted up or down, and to meet final requirements forfne or minute changes, the adjustable pusher pin I8 on the spring end of the lever I2 is provided,-

which when adjusted will be effective on all of the pistons 1 and their respective cylinders 6, with respect to cylinder compression.

The use of the dash-pot I6 in conjunction with the shaft II, will dampen-out pulsation at the lever l2, and the oil body beneath the piston 23 which is drained at times of engine shut-down for unloading the spring 2I, while not essential a small degree, the cylinder pressures of all cylinders during all cycles of operation increase a commensurate degree, as the vacuum created during suction strokes is'less intense, the compression resistance greater, as well as the expansion pressures being greater.

In addition, there will be some increase in cylinder gas pressures while exhausting spent -gas charges, thus the algebraic sum of instantaneous cylinder pressures will increase and result in rcking the shaft II until the increased compression on the spring 2| will just counterbalance the increased forces on the pistons 1, and simultaneduring normal operation, does assure a most prompt outward movement of the pistons 1, during the first 1A revolution of starting the engine, to eliminate possible excessive compression and pre-ignition at initial starting operation.

While an embodiment of the invention is here shown and described, obviously many others may occur to those skilledin the particular art. I, therefore, do not limit myself to the details described, but claim as my invention all variations and modifications within the scope of the subjoined claims. e

What I claim is:

1. A cylinder for an internal combustion engine having a movable wall with manually adjustable means therefor, and automatically actuated means cooperable to move said wall between adjustably xed positions.

2. A cylinder for an internal combustion engineV having a manually adjustable movable wall in axial alinement with the cylinder, automatically actuated means cooperable to move said wall to decrease or increase the ring chamber of the cylinder and a pair of adjustable limiting stops cooperable with said means.

forming a part of the ilring chamber thereof, and spring actuated linkage cooperable with said wall to move it between iixed predetermined positions.

A5. A multi-cylindered internal combustion en- -ginev having a manually adjustable movable wall chambers.

6. A multi-cylindered internal combustion eri-- gine having a manually adjustable movable wall formingl a part of the firing chamber of' each cylinder, and spring actuated means cooperable to 'move all of said walls either inwardly or outwardly to vary distances in respective firing chambers.

7. A multi-cylindered internal combustion engine having a manually adjustable movable wall in axial alinement with respective cylinders and forming `a part of the iiring chamber of each cylinder, and 'resiliently actuated linkage cooperable to move all of said walls either inwardly or outwardly of respective cylinders.

8. A multi-cylindered internal combustion engine having manually adjustable cylinder heads, spring actuated linkage cooperable to move said heads varying distances between adjustably iixed stops, and a pulsation eliminator cooperable with said linkage. f

9. A multi-cylindered internal combustion engine having movable cylinder heads, a rock shaft, individually adjustable linkage connecting said heads to the rock shaft, and a spring actuated lever connected to said rock shaft having adjusting means at one end thereof.

10. A multi-cylindered internal combustion engine having movable cylinder heads, a rock shaft, individually adjustable linkage connecting said heads to the rock shaft, a spring actuated lever connected to said'rock shaft having adjusting means at its extending end, and a uid actulnder, and a coil'spring cooperable at 'one end with said piston and at its other end with said lever.

cylinder and a communicating firing chamber, a

movable head in said flring chamber, a lever connected to said head, a cylinder having an oil pressure supply source. a pistonin said oi1 cylinder adapted to be actuated bythe oil pressure therein, a coil spring interposed between said lever and said piston, and a piston stop at the Outer end of said oil cylinder.

14. A cylinder foran internal combustion engine having a. movable wall, automatically actu- Aatedlmeans cooperable to move said wall to positions intermediate its movable length, and-other means effective on said rst means during starting of the engine.

15. The methodof operating a variable compression ratio internal combustion engine, consisting of the automatic selection of a predetermined minimum compression ratio for the duration of the enginestarting operation, and of subsequently and automatically selecting compression ratios approximately inversely proportionate to the developed engine torque.

16. A cylinder for an internal combustion engine having a movable wall, spring actuated means cooperable to move the wall to decrease or increase the firing chamber of the cylinder, and automatic means cooperable to increase the spring pressure of said first means.

17. A multi-cylindered internal combustion en gine having manually adjustable cylinder heads, and fixed stops betweenwhich said heads are automatically positioned. l

18. A multi-cylindered internal combustion engine having respective cylinder heads, a rock shaft, and adjustable linkage connecting said heads to the rock shaft.

ated piston cooperable with the spring of said able stops cooperable with said lever.

1'2. A multi-cylindered internal combustion engine having movable cylinder heads, a rock shaft,

individually adjustable linkage connecting said heads to the rock shaft, a lever secured to said rock shaft, a fluid cylinder, a piston in said cyl- 19. An internal combustion engine having a cylinder and a communicating firing chamber, a. movable head in said ring chamber, a spring actuated lever cooperable with said head, an adjustable stop to limit outward movement of said head, and manually adjustable means located between said head and said lever.

20. An internal combustion engine having a cylinder and a firing chamber, a movable head in 'said firing chamber, a lever, manually adjustable means connecting said lever to said head, a cylinder having a uid pressure supply source, apiston in said fluid cylinder adapted to be actuated by the iluid pressure therein, and a spring interposed between said lever andV said piston.

` HERBERT J. KRATZER.`

13. An internal combustion engine having a