DE1925743A1 - Valve construction for pistons with changeable compression ratio - Google Patents

Description

Continental Motors Corporation
Detroit, Michigan, VStA

Valve construction for pistons with variable compression

ratio ■ ^ __

The present invention relates to an internal combustion engine and in particular to one which is provided with a device for changing the compression ratio. The invention is specifically directed to an improved device for controlling the relative movement of two-part pistons, as honored in the USA patents 3,156,162, 3,161,112, 3 185 137; 3 185 138; 3 303 831 3 311 096 of the applicant are.

In each of the cited patents there is a two-part piston with variable compression ratio disclosed, wherein an inner part or a piston pin carrier in the usual Way is connected to a piston rod and carries an outer part or shell part which is intended to be axially in to move a limited amount relative to the inner part. Gaps are provided between the top of the inner part and the bottom of the outer part, which form an upper and lower variable volume chamber,

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which contain an incompressible medium, for example oil. By controlling the flow of oil to and from these chambers, the movement of the outer part relative to the inner part is made responsive to the piston reciprocation and the Combustion chamber pressure controlled to keep the free volume in ddm Cylinder in which the piston moves back and forth to change and thus the compression ratio of the engine.

In addition, U.S. Patent 3,303,831 discloses a sol-

before construction comprising a pressure regulating valve that so is arranged that its direction of movement is parallel to the movement of the piston and it opens in the direction is moved to the upper chamber. By arranging and constructing a valve in such a manner, the effects The force of gravity in the operation of the valve, as generated at higher machine speeds, is canceled and such increased gravity is used to assist in opening the valve.

Also in this particular patent is a design disclosed for a pressure regulating valve in which a small working surface is exposed to the oil, so that a small Pressure is required to lift the valve. Has that a

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times have taken place, a larger work surface is the Pressurized so that the valve opens quickly.

The present invention makes a pressure regulating valve available that takes advantage of the US patent design 3 303 831 and additionally has a device accessible from the underside tdjfes piston, is used to set the counteracting the Venix release " Spring tension so that the valve can be adjusted quickly

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can, τιτη the combustion chamber pressure einur% g% ^ erön at which it should open. Previously, such an adjustment day was not possible and if it was found that the "valve opened at incorrect combustion chamber pressures" it was necessary to remove the valve and replace it with a new one. This was a difficult operation and required the disassembly of a substantial part of the engine * ·

Other objects and advantages of the present invention will --SiCH undergo an embodiment of the Erfmdiaaig defrosted reference to the accompanying drawings in the following description, like reference characters in the check in various Kgiarea AAIF same parts refer, lh the drawings

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Fig. 1 is a vertical sectional view through the

Axis of a piston construction according to the present invention;

Fig. 2 is an enlarged sectional view of the pressure regulating drain valve the invention of Figure 1;

FIG. 3 shows a view corresponding to FIG. 1, with the valve in the open position; FIG.

Figure 4 is a cross-sectional view taken along line 4-4 in Figure 2;

5 is an enlarged sectional view of the feed valve the invention of Figure 1; and

FIG. 6 is a sectional view taken along line 6-6 in FIG. 5.

In the drawings there is a variable compression ratio piston 10 shown moving back and forth in the bore of a cylinder of an internal combustion engine. Of the Piston consists of two parts, an outer or shell part 12 that rests on an inner part or piston pin carrier 14 is stored. The outer part 12 has a head 16 which serves as the head of the piston 10 and a movable wall of the forms the lower limit of the combustion chamber. The inner part 14 is axially displaceable within the outer part 12 and is provided with rings 18, 20 and 22, the * ab-

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sealingly after the inner surface of the part 12 are in contact. The inner part 14 is attached to the crankshaft of the engine by a piston rod 26 and a piston pin 28 in the conventional one Articulated way. In such a manner, the inner member 14 is axially between defined upper and lower limits movable in the manner of a conventional piston while the outer part 12 can be moved axially up and down relative to the inner part 14 within limits set forth below should be described.

An upper variable volume chamber 30 is between the upper surface of part 14 and the lower surface of the head. A lower variable volume chamber 32 is between the lower surface, which is defined by an annular recess is formed at the lower end of the inner part 14 and the upper surface of a ring 14 which is formed on the outer part 12 is attached, formed. A sealing ring 36 is through the Ring 34 is held adjacent the faces of part 14 and the ring. A throttle opening 37 formed in the ring 34 connects the lower chamber 32 to the crankcase of the engine.

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The ring 34 and the lower surface of the head 16 defining the chamber 30 define the limits of axial movement of the outer Part 12 relative to the inner part 14. This relative movement. allows a variable height from the center of the piston pin 28 to the top of the piston head 16, thereby increasing the compression ratio of the motor is changed.

The movement of the outer part 12 upwards (Fig. 1) is relative to the inner part 14, the upper chamber 30 expands, while the contraction of these parts expands the lower chamber 32. This movement of the outer part 12 relative to the inner Part 14 can then be controlled automatically by regulating the flow of incompressible fluid in and out of chambers 30 and 32. In the present invention, the control medium is preferably oil, which is the Piston 10 from the usual pressure lubricant supply of the The engine is supplied through an oil passage 40 formed in the piston rod 26.

The passage 40 preferably stands in with an annular groove 42 Connection surrounding the piston pin 28 and to the outlet which is connected to a passage 52 which is formed in the inner part 14 via a slide collector device 47

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is. The slip collection assembly 47 is similar to that disclosed in the aforementioned patents and is preferably comprised a header cap 48 supported in a cavity 46 formed in the inner part 14 and supported by a spring 50 is urged into sealing contact with the surface of the piston rod 26 so that the oil from the outlet 44 to the Inside the cap 48 in all positions of the connecting rod 26 is urged with respect to the axis of the bolt 28. An opening 51 is provided in the collector cap 48, which the oil leads to passage 52. The passage 52 connects the upper chamber 30 and the lower chamber 32 through a supply valve arrangement, which is indicated generally at 56.

The connection between the supply valve assembly 56 and the upper chamber 30 is established through the passage 60 (Fig. 5) and the connection between the supply valve assembly 56 and the lower chamber 32 is established by the passage 62.

A pressure regulating drain valve, indicated generally at 64, connects the upper chamber 30 to the crankcase atmosphere, as Fig. 1 shows.

The feed valve assembly 56, as best shown in Figs

1 0 9 8 1 6/0 9 B 0

as can be seen, preferably comprises a seat 66 with stops 68 located at each end and is in Steklung by a distance cylinder 72 and a retaining ring 74 mounted. The seat member 66 is provided with an outer annular groove 76 which is aligned with the passage 52 and is in communication with the interior by means of the passage 78 via a Row of spaced apart in a ring

w openings 80. The valve seats 82 are formed at each end of the passage 78 and are designed to contact the valve plates 84. The ends of the seat member 66 are provided with protruding cylindrical portions 86 which come into contact with the stops 68 so that a chamber 88 is formed at each end of the seat member 66 between the seats 82 and the stops 68 to make an area available which allows the valve plates 84 to move between a position closing the passage 78 and a position in contact with the stop 68, thus opening the flow from the passage 78 to the chamber 88.

As best shown in Figure 6, the valve plates are tendon-removed Parts 89 fitted as a precaution that the valve plates 84 do not interfere with the inner surface of the protruding

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Wedge parts 86 in any intermediate position. The stops 68 are also of a larger diameter than that Valve plates 84 and are formed so that they form radially extending tongues 90 so that the oil through the Clearances between the tongues 90 can flow when the valve plate 84 is in position against the stop 68.

The drain valve assembly 64, as best shown in FIG. 1 through 4, preferably comprises a tube-like one Valve part 92, a guide part 94 and a spring 96.

The guide file 94 is seated in a lower threaded part 98 of a bore 100, the upper end of which with the upper chamber 30 aligns. The upper outer part of the guide part 24 is provided with an external thread and, as best shown in FIG. 4 showf, with a plurality of equally spaced axially extending grooves 10Θ. The lower outer part of the guide member 94 is formed in the manner of a screw head, such as shown at 104 so that the guide member 94 with a suitable wrench in position in the threaded portion 98 of the Bore 100 can be brought. A spring-loaded plunger 105 is preferably in part 14 in a

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Position stored, to be moved into one of the grooves 102 ■ ·· and thereby fix the guide part 94 in a rotational position. An internal bore 106 formed in the upper end of the guide member 94 is formed, axially slidably receives the lower end of the tubular valve member 92 on.

The valve member 92 is hollow and ends open at the top to a zenfc to form the central passage 108, which is connected to the upper chamber 30

is in communication and is with an intermediate part 110 with enlarged Diameter provided which forms a seat for the lower end of the spring 96 to the lower end of the valve member 92 into the bore 106 of the guide part 94 and thus to close the lower open end of the passage 108.

The lower end 113 of the valve 92 is sized to fit snugly in the bore 106 for proper movement of the valve member 92 to ensure. An outer annular groove 114 is formed over and extends to the lower end 113 enlarged portion 110. A plurality of openings 116 provide a connection between the central passage 108 and the Groove 114. The upper rectangular ring surface 118 of the valve guide 94 forms a valve seat and the spring 96 urges the valve member 92 into the position shown in FIG

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lower end or the valve surface of the part 110 with the Valve seat 118 is in contact to allow oil flow from groove 114 and between the valve surface of member 92 and complete the valve seat 118.

When the valve member 92 moves to the open position illustrated in FIG. 3, oil flows from the channel 30 through the passage 108, the openings 116 and past the valve seat 118 or the valve surface of the part 110 to to flow axially through the grooves 102 of the valve member 94 to the crankcase. In order to influence the passage of the Oil past that. to reduce open valve member 92 is an annular recess 119 preferably formed in the part above the valve surface 118 *

The opening of the valve member 92 is achieved by the oil pressure which acts on a part 120 of the valve surface which the forms the upper limit of the groove 114 and which is exposed in the oil in the passage 108 when the valve 92 is closed and thus the pressure within the upper chamber 30. If the valve member 92 moves once to an open position, then a part 122 of the valve surface, which is normally with the seat 118 is in contact, including the oil pressure in the

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Passage 108 exposed.

Assume that the combustion chamber pressure is below the predetermined one Maximum valve pressure that the piston 10 should maintain • and the upper and lower chambers 30 and 3 2 * are both filled with oil, so there is during the last part of each upstroke of the piston 10 at the end of the exhaust stroke and the

ψ the first part of each downward suction stroke

the momentum of the outer part 12 the inclination, it upward relative to move to the inner part 14, the tendency occurs that expand upper chamber 30 and compress lower chamber 32. The resulting increase in oil pressure in the lower chamber 32 causes the lower valve * plate 84 of the supply valve assembly 56 is moved upward against the lower valve seat 82 to the flow of oil from the Passage 52 to lower chamber 32 to close. This creates a hydraulic lock between parts 12 and 14 due to the oil contained in the lower chamber 32 with the result that during each cycle of the engine operation an upward relative movement of the outer part 12 with respect to the inner part 14 is very small and only to the extent that oil is allowed from the lower chamber 32 can escape through opening 37 * In the same way,

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1325743

the inclination of the upper chamber 30 affects itself during this To extend the piston actuation position, the top plate 84 of the supply valve assembly 56 extends into the top Position against the stop 68 moved to the oil flow of the passage 52 to the upper chamber 30 to open.

A controlled discharge from the lower chamber 32 through the orifice 37 then allows a gradual cyclical Decrease in the volume of the lower chamber 32 and thus a corresponding increase in volume in the upper chamber 30 to the relative upward movement between the outer part 12 and the inner part 14 to enable. When the upper chamber 30 increases the volume, oil is drawn from the lubrication system through the supply valve assembly 56 into the upper chamber 30 to keep the chamber in a filled state. '.

During the compression and power stroke, the gas pressure acting on the piston head 16 is transmitted to the inner part 14 through the oil in the upper chamber 30, which creates a high oil pressure in that chamber. If the gas pressure exceeds the selected upper limit, sufficient oil pressure will build up in the upper chamber 30 to close the drain valve 64

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open and release oil, the outer part 12 moving downward relative to the inner part 14 and thus the Compression ratio of the engine is decreased. The relative downward movement of the outer part 12 increases the Chamber 32 and the lower valve plate 84 of the supply valve assembly 56 is moved to a position against the lower stop 68 to close the lower chamber 32 to the passage 52 open and oil enters the lower chamber 32 to put it in to keep the filled state.

The amount of oil drained from the upper chamber 30 during a compression stroke depends on the deviation, at which the cylinder gas pressure exceeds that necessary to cause the vent valve 64 to open and the duration of this excess pressure. The valve spring setting and the length of the duration of the excess gas pressure determine the downward movement of the outer part 12 relative to the inner part 14. The relative upward movement on the other Page is the same on every exhaust and intake stroke and is determined by the size of the specified opening 37. If the relative upward and downward movements are the same, which is the case when the engine is running under constant load, the effective compression ratio remains unchanged. if

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As the load increases, the downward movements exceed the upward movements, reducing the compression ratio until equilibrium is established. ^! Conversely, when the load is decreased, the compression ratio increases to a new equilibrium point.

In the operation described above, it is assumed that the piston is moving at a constant speed moved back and forth. It has been found, however, that in conventional spring loaded pressure regulated valves, to to control the pressure in the upper chamber 30, the combustion pressure has a tendency to expand beyond the desired maximum as the machine speed increases. This is partly due to the increased effect of the momentum at high machine speeds. With conventional valve constructions, the inertia acts on opening the Valve and since the inertia increases with the square of the machine speed, opens at high speeds do not operate the valve until the desired maximum combustion pressure has been exceeded. The pressure regulating relief valve 64 of the present invention is designed to overcome these problems and provide an im substantially uniform maximum combustion chamber pressure

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is maintained regardless of the machine speed.

Due to the orientation of the tubular valve member 92 so that it moves in a direction parallel to the movement of the piston 10 and due to the valve closing movement in the downward direction away from the cylinder combustion chamber, the is through the spring 96 exerted valve closing force. the inertia forces opposite, which act on the valve member 92 when the piston slows down as the top dead center is approached and then accelerates again in the opposite direction when it has passed top dead center. This inertia force on the valve member 92 increases proportionally to Square of the machine speed and acts as an opening force on the valve member 92, which changes with the machine speed enlarged. Since the inertia force counteracts the valve-closing force of the spring 96, the The force required to open the valve member 92 is reduced as the machine speed increases. That in turn causes the valve member 92 by the pressurized oil in the chamber 30 at a lower pressure at higher Speeds than opening at lower speeds. This enables the valve member 92 to do what is required.

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Volume of oil from chamber 30 to compensate for an increase in combustion chamber pressure regardless of the Lower the machine speed.

Since the inertia forces act parallel to the direction of the valve movement, these forces do not affect the frictional contact of the valve member 9'2 neither with the valve guide 94 or with the wall of the bore 100. Thus, by the intended mentioned alignment in l / i closing direction of the valve member 92 relative to the piston movement and the combustion chamber, the desired maximum combustion chamber pressure is maintained approximately uniformly by the piston 10.

The present invention, similar to the aforementioned U.S. Patent 3,303,831, includes a small work surface in the shape of the valve face portion 120 to open the valve, creating a softer spring and less material for the Valve member 92, as already described in the patent, is enabled. Next is the valve member 92 of the present invention provided with an enlarged working surface by the part 122, that after which the valve member 92 is lifted is subjected to the pressure of the oil flowing from the passage 108 of the valve member 92 to a sudden

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Increase in valve opening force, resulting in a snap opening response, which is beneficial in achieving instant control of the oil pressure in the chamber 30 is.

While the invention is in some respects similar in construction of the last-mentioned patent, it offers

"Substantial improvements over that in the patent

disclosed construction. This improvement is the provision of a valve guide member 94 and the particular one Way of mounting within the lower end of the bore 100 so that the bolt head is from a key can be achieved for adjusting movement of the guide member axially within the bore 100. It is evident that the setting of the position of the valve guide part in the drilling

) tion 100 also the position of the valve seat 118 and the valve member 92 adjusts in a closed position and thereby the bias of the valve 94, generated by the spring 92, y changed. In this way it is then possible to set the combustion chamber pressure by hand at which the valve 64 opens. This is a significant improvement, as previously such a setting could only be achieved by removing the Valve arrangement and replacement with a new fixed setting

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th valve arrangement or by replacing the spring. the present design allows adjustment to get the best results after the machine has run. The tappet assembly 105 ensures that the valve guide assembly 94 is not out of its set position deviates during machine operation.

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Claims (9)

19 ^ 5743 PATENT CLAIMS Valve construction for pistons with variable compression ratio, which consists of a first and a second part consists, relative to one another, in response to the reciprocating movement of the piston with respect to the combustion chamber are movable, wherein a pressure medium chamber is provided in the piston, which changes its internal volume responsive to the relative movement and changes in the amount or pressure present therein, characterized by the combination of a liquid passage which is in communication with the pressure chamber, a valve member movably supported by the piston to open and close the passage for control of the pressure medium to the amount of the pressure medium in the pressure chamber to change, a device that yields the valve member in the closed Location urges to regulate the pressure of the fluid in the pressure chamber, and a device for displaceably mounting the valve member with a valve seat which is contacted by the valve member to close the passage, whereby a part of the end of the passage opposite the pressure medium chamber is accessible 109R1R / np
COPY is and is optionally movable within the passage to change the position of the valve seat and thereby the To change fluid pressure that actuates the valve member. 2. Arrangement according to claim 1, characterized in that that that valve member is provided with a first working surface of a predetermined size which corresponds to the pressure medium pressure in the pressure medium chamber is exposed in the open and closed position, the DEUck has the tendency that the Lift off the valve member and that the valve member is provided with a second working surface, the pressure in the pressure medium chamber is only exposed when the valve member is lifted, the second working surface reinforcing the first and the The opening force exerted by the fluid pressure is increased when the valve member is increased by the fluid pressure in the pressure chamber is lifted. 3. Arrangement according to claim 1 or 2, characterized in that the storage comprises a valve guide part which forms the valve seat and that the valve member further comprises a first externally enlarged part which forms a radial surface., who eats silently to sit on the valve seat in such a wine that part of the radial surface becomes the first 1 0 9 R 1 IW Π 9 B 0 COPY ί Forms working surface and is exposed to the fluid on the inlet side of the valve member, another part of the radial surface forms the second working surface and rests on the valve seat and is therefore only exposed to the pressure medium, when the valve is lifted. 4. Arrangement according to one of claims 1 to 3, characterized in that the bearing comprises a valve guide part, which sits in the passage, that the valve member is tubular and rests against the valve guide part, around the flow of pressure medium through the center of the valve cover to complete that the biasing means comprises a spring that the valve member pushes against the valve guide part and that the valve seat adjustment part it enables the valve guide member to move axially in the passage, the tubular valve member is moved towards or away from the spring. 5. Device according to one of claims 1 to 4, characterized in that the passage is the pressure medium chamber connects with the crankcase of the engine that the bearing comprises a valve guide part, dns an upper recess «• Mounted and adjustable at the lower end of the passage Jst, with a plurality of axially extending passages 1 0 9H 1 K / 9ΡΌ
COPY passages connect the passage to the crankcase, that the valve member is tubular and seated in the recess of the valve guide part to establish the connection between to close off the interior of the valve member and the part of the passage via the valve guide part. 6. Arrangement according to one of claims 1 to 5 _J, characterized in that the valve is aligned for a movement parallel to the direction ■ · <_ of the reciprocating movement of the piston and that the valve closes in the direction that is opposite to the inertia forces acting on the valve when the piston in the combustion chamber slows down. 7. Arrangement according to claim 6, characterized in that that means for adjusting the position of the valve guide part axiaj. in relation to the passage is provided and that with the setting, the bias and thus the pressure can be adjusted at which the valve member opens. 8. Arrangement according to claim 6 or 7, characterized in that the adjusting device of the lower side of the Piston is accessible. 109R1R / O960 COPY 9. Arrangement according to one of claims 6 to 8, characterized characterized in that the guide member is provided with an externally threaded portion which sits in an internal thread of a portion of the passage and that the valve guide member is axially movable along the threaded surface of the passage to adjust the position of the valve member when it is closed and thus the pressure at the the valve opens, wohei ψ means for selectively locking the valve guide member in the desired rotational position against an undesired axial movement is provided. 109S1fi / n96Ö Blank page