DE1476111A1 - Pistons for internal combustion engines - Google Patents

Description

Socilte D'Exploitation dee Materials Hispano-Suiza Rue du Capitaine Guynemer, 92 Bois-Colombes, France Pistons for internal combustion engines Priority: France, December 29, 1964

The invention relates to the pistons for internal combustion engines consisting of two parts, namely a middle one for coupling with one Connecting rod certain, hereinafter "central body" called part and a supplementary part, which with a certain axial movement on the central body slides and hereinafter "sliding hood" is called, with the through the central body and the sliding cover formed arrangement delimits without an intermediate chamber, which is intended for a liquid is and duroh at least one inlet opening and one outlet opening is supplied. Concerned by such pistons the invention in particular, albeit not exclusively, those for internal combustion engines of the diesel type.

009841/0141

The invention aims in particular to design such pistons so that they better than before the various requirements correspond to practice, especially with regard to their lifespan.

For this purpose, according to the invention, the opposing wall parts of the central body and the sliding hood are designed in such pistons so that when the sliding hood approaches the central body under the action of a certain value of the pressure which is reached in each working cycle in the cylinder cooperating with the piston in question and hereinafter referred to as "control pressure", this approach closes the inlet opening and the outlet opening at the same time, which supply the intermediate chamber, so that a fluid volume is included in each work cycle, which carries out the transmission of the axial forces between the sliding cover and the central body in whole or in part.

According to a further feature of the invention, the central body made of light alloy and the sliding hood is made from a high temperature resistant metal "ei such a piston, an axial guide of these two parts is provided by surfaces where appropriate, of which at least some separated by grooves, which has a circumferential cooling liquid can absorb speed , whereby the heating of the sliding cover is reduced to a considerable extent.

The invention is explained below by way of example with reference to the drawing.

Fig. 1 is an axial section of a first embodiment of a Piston according to the invention, the components of which are shown in a remote position.

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Fig. 2 shows in an axially sectioned partial view of the piston shown in Fig. 1, its components however, are approximated to each other.

3 is a partial, axially sectional view of one formed in accordance with another embodiment of the invention Piston, the components of which assume a position apart from one another.

Fig. 4 shows in an axial section with hidden parts the piston shown in Fig. 3, its components but take an approximate position.

FIG. 5 is a section along line V-V of FIG. 1.

FIG. 6 is a partial view of a component part of the piston shown in FIG.

The illustrated embodiments relate to an application of the invention to pistons of diesel engines.

The diesel engine to be equipped with such a piston 1 is designed and possessed in any suitable manner in any case, as shown in FIG. 1, a cylinder 2 and a cylinder head 3.

The piston 1 consists in a manner known per se of two parts, namely a central body 4, which has the general shape of a piston and therefore has a base 5 and a jacket 6, and is coupled to a connecting rod 7 by means of a piston axis 8, as well as a Sliding hood 9 _f wel che the general shape of a thin-walled piston and dfcer a bottom 10 and a jacket 11 has.

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The sliding hood 9 slides on the central body 4 with a certain axial movement possibility, and through the Center body 4 and the sliding hood 9 formed arrangement borders between the outer surface of the bottom 5 of the center body 4 and the inner surface of the bottom 10 of the sliding hood from an intermediate chamber 12, which with a pressure P standing liquid is flushed, which is expediently Cl, z. B. the shearing] of the engine.

The intermediate chamber 12 is then through at least one inlet opening and supplies at least one outlet opening, the latter being dimensioned so that in the intermediate chamber a pressure which is practically equal to the pressure P is maintained. The formation of these openings is further described below.

Finally, the piston 1 formed in this way carries a certain number of piston rings 13, e.g. B. five, of which at least part of the jacket 11 of the sliding hood 9 is carried.

In the embodiment shown, three piston rings are attached to the sliding cover 9, and one piston ring is attached to the central body 4 axially between the sliding hood 9 and the piston axis 8 and a piston ring from the central body 4 in the lower part of the coat 6 of the same worn.

According to the invention, opposing wall sections of the central body 4 and the sliding hood 9 are designed in such a way that the sliding hood 9 approaches the central body 4 by a sliding movement under the action of a control pressure P which is reached with each working cycle in the cylinder 2 cooperating with the piston 1 is, this approaching movement at the same time closes the inlet opening and the outlet opening, which the

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Supply intermediate chamber 12.

It is then evidently included in each work cycle, a certain volume of the fil, which wholly or partially the Transmission of the axial forces between the sliding cover 9 and the central body 4 is effected and at least partially in each case Working cycle is regenerated.

For this purpose, according to a first embodiment shown in FIG. 1, the sliding hood 9 is guided axially by means of the inner walls of its shell 11 and the outer walls of the upper section of the shell 6 of the central body 4.

The possibility of axial movement of the sliding hood 9 in the sense of its distance from the central body 4 is limited in that the base 10 of the sliding hood 9 has an axial extension 14 which extends into a central bore 15 formed in the base 5 of the central body 4, and to which a stop washer 16 is attached by means of a bolt 17

The limitation of the axial movement of the sliding hood 9 in the sense of its approach to the central body This is achieved by the fact that on the outer surface of the bottom of the central body 4 there are two contact surfaces 18 and 19 which are expedient are annular and concentric and surround the central bore or lie on the circumference of the bottom 5, and on the Inner surface of the bottom 10 of the sliding hood 9, two contact surfaces 20 and 21 are provided, which are annular and concentric and lie opposite the contact surfaces 18 and 19, respectively.

The supply of the Druok oil to the Zwiachenkaaer 12 takes place

BATH

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then through several inlet openings, each of which is formed by a ^{slot 22, hereinafter referred to as "axial slot 11} ", which has at least approximately one axial direction and lies on the circumference of the bottom 5 of the central body 4. The upper end of this axial slot 22 opens at the location of on this bottom 5 provided contact surface 19, while its lower end opens into a distribution groove 23, which is formed in the central body 4 and is explained in more detail below.

The oil emerges from the intermediate chamber 12 through a calibrated outlet opening, which is formed by an annular space 24 between the axial extension 14 and the central bore 15, with discharge openings 24a then being formed in the stop disk 16 attached to this axial extension 14.

If, with this design, the pressure acting on the outer wall of the bottom 10 of the sliding hood 9 is less than the steering pressure P ₀ , the sliding hood 9 and the central body 4 assume a position at a distance from one another under the effect of the pressure P of the oil (FIG. 1). . The contact surfaces 18 and are removed from the contact surfaces 20 and 21, the axial slots 22 for the oil supply and the annular space 24 for the oil discharge are exposed.

If, on the other hand, the pressure acting on the outer wall of the base 10 dtr sliding hood 9 is greater than the control pressure P _Q , the sliding hood 9 and the central body 4 assume a position closer to one another under the effect of the pressure exerted on the base 10 (flg. 2). The abutment heights 18 and 19 are in contact with the abutment surfaces 20 and 81;

BATHROOM ORIGINAL 1 -

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Contact surface 21 and the annular space 24 through the contact surface

20 locked.

In this latter case, the axial surface is evidently transmitted between the sliding cover 9 and the central body 4 z. T. via the oil volume enclosed in the intermediate chamber 12 and z. T. about the two between the contact surfaces 18 and 20 and the contact surfaces 19 and

21 created layers of oil.

The following is another embodiment shown in FIG in which the same reference numerals denote the same parts as in FIG.

In this embodiment, the sliding hood 9 is axially only through part of the inner walls of its shell 11 and the outer walls the upper portion of the jacket 6 of the central body 4 out.

The limitation of the axial movement of the GJeithaube 9 in the sense of its removal from the central body 4 takes place in the same way as in the case of that shown in FIG Embodiment.

The possibility of axial movement of the sliding hood 9 in the sense of its approach to the central body is limited in that the jacket 6 of the central body 4 is provided with a shoulder 25 which cooperates with the lower edge of the jacket 11 of the sliding hood 9.

The supply of the pressure oil to the intermediate chamber 12 then takes place through a plurality of inlet openings, each of which is formed by a slot 26 , hereinafter referred to as "radial slot", which is at least approximately radial and on the circumference

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of the bottom 5 of the central body 4 is located. The inner end of this radial slot 26 opens directly into the intermediate chamber 12, while its outer end can open into a complementary distribution groove 27, explained in more detail below, which is in the inner wall of the jacket 11 of the sliding hood 9 is formed at the location of the distribution groove 23.

The exit of the oil from the intermediate chamber 12 takes place through a calibrated outlet opening, which as in the previous one Case is formed by the annular space 24 between the axial extension 14 and the central bore 15. The a The axial extension 14 is provided here with a shoulder 28 which slide in the central bore 15 without radial play can.

', Venn in this training of the on the outer wall of the floor the pressure acting on the sliding hood 9 is less than the control pressure P, the sliding hood 9 and the central body 4 take under the effect of the pressure P of the CI is a distant one Position (Fig. 3).

The outer end of each radial slot 26 then opens in the complementary distribution groove 27, and the shoulder 28 of the axial extension 14 is not in the central bore 15 occurred. The radial slots 26 and the annular space 24 are exposed and therefore cause the oil supply and the Oil drainage.

If, on the other hand, the pressure acting on the outer wall of the bottom 10 of the sliding hood 9 is greater than the control pressure P, take the sliding hood 9 and the central body 4 under the action of the pressure exerted on the floor 10 one another

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approximate position (Fig. 4). The outer end of everyone Radial slot 26 is closed by the inner wall of the shell 11 of the sliding hood 9, while the annular space 24 by the Shoulder 28 of the axial extension 14 is closed.

In this latter case, the axial forces are evidently transmitted between the sliding hood 9 and the central body 4 completely over the volume of oil enclosed in the intermediate chamber 12.

It should also be noted that in both embodiments, the distribution of the openings for supplying the pressure oil to the Intermediate chamber 12 forming slots (axial slots 22 or radial slots 26) through the on the outer surface of the bottom the sliding cover 9 detected thermal loads is determined.

If z. B. provided the equipped with inventive piston 1 Diesel engine with a cylinder head 3, which has a swirl chamber 29 and a Überführungsdurchlaß 30 has, as is shown schematically in Fig. 5 for the case that the feed openings are Axialsohlitze 22, which is at The zone of the floor 10 lying at the point of the transfer passage 30 is exposed to a considerable thermal load. A large number of inlet openings are therefore provided at the location of this zone. By way of example may be stated that in this case, 70 fo the Druekölmenge this zone are supplied, while the remaining 30 ° f are uniformly distributed on the periphery of the bottom 10th

So far nothing has been said about the materials of the central body and the sliding hood 9 and the axial guidance of the sliding hood on the central body 4 (except that this guidance takes place at the location of the shell of these two parts).

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According to a further characteristic of the invention, "the central body 4 consists of a light alloy, which is preferably selected from alloys which have a strong silicon content, such as the alloy known under the name" AS 12 UN ", which is $ 12.50 Contains silicon, $ 1.50 copper, $ 1.25 > nickel and 0.75 % iron, while the sliding cover 9 consists of a high-temperature-resistant metal, such a metal which is brought to a temperature of 400 ° locally with each work cycle is preferably selected from austenitic steels or refractory steels with a high chromium content, such as that known under the name "SIMO", which contains 10 $ chromium, 2.50 % silicon, 0.80 $ molybdenum, 0.80 Contains manganese and 0.40 ? O carbon.

Ss can then expediently an axial guidance of the sliding cover provided on the central body 4 with the aid of guide surfaces 31 at least some of which are provided by distribution grooves 32 for receiving a circulating cooling liquid are separated.

The Italauf this coolant, which as above be oil can, for example the lubricating oil of the engine, apparently reduces the heating of the sliding cover 9 to a considerable extent.

For this purpose, as shown in Fig. 1, 3 and 6, on the Place of the upper portion of the outer surface of the jacket 6 of the central body 4 two distribution columns 32 are provided, namely a lower and an upper, which lie on both sides of a guide surface 31 and with each other through a certain Number of evenly distributed on the surface 31 axial Passages 33 are connected.

It should be noted that in the embodiment shown in FIG the upper distribution groove 32 is actually the

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Forms distribution groove 23 into which the lower end of each axial slot 22 opens, while in the case of the one shown in FIG illustrated embodiment, the upper distribution groove 32 in reality forms the distribution groove 23, which with the complementary distribution groove 27 is intended to cooperate, in which the outer end of each radial slot 26 open can.

In any case, there is at least one sealing ring between the lower groove 32 and the lower part of the casing of the sliding cover 9 34 provided.

In order to improve the distribution of the oil, at least some of the axial passages 33 can then expediently be coated with paint with respect to the distribution of the axial slots 22 or the radial slots 26 can be arranged.

Facilities are provided which remove the oil from the convey a certain amount of pressurized oil, not shown, to the lower distribution groove 32. These devices comprise an arrangement of channels, not shown, for conveying the pressurized oil up to the Connecting rod head, a channel 35 formed in the connecting rod 7, one formed in the foot of the connecting rod 7 Distribution groove 36, a distribution opening 37 for supplying the oil to the interior of the hollow piston axis 8, which at their both ends closed by two plugs 38 and on one Rotation in the central body 4 by a locking screw 39 is prevented, two formed in the piston axis 8 in the vicinity of its two ends, facing the upper part of the piston Openings 40, two axial channels 41, which axially extend the openings 40 in the central body 4 and up to about in place of the lower distribution groove 32, and two radial lines 42 for connecting the lower distribution

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- 12 groove 32 with the two axial channels 41.

With this training, the circulation takes place when the pressure in the cylinder is smaller than the control pressure P, in the sense of the arrows entered in FIGS. 1 and 3.

The control pressure P depends mainly on the one hand Pressure P of the oil supplied to the intermediate chamber 12 and on the other hand on the ratio of the pressure P and that in the cylinder 2 surfaces exposed to pressure.

As an example, it should be stated that at a pressure P of

about 5 kg / cm, the control pressure P is of the order of magnitude

2
4 kg / cm.

Under these conditions the oil circulation takes place in a four-stroke diesel engine during the entirety of the intake stroke, during the start of the compression stroke and during almost the entirety of the exhaust stroke.

Finally, it should be noted that this is in the intermediate chamber 12 enclosed oil volumes like a ", Värmefalle behaves, since the temperature of the CI when it is fed into the intermediate chamber is relatively low (about 80 °) im Relation to the mean temperature of the bottom 10 of the sliding hood 9 (about 250 °).

The above piston has, inter alia. the following advantages:

The sliding cover, which has to withstand the greatest thermal loads, is cooled by an oil circulation and a heat trap effect, whereby the service life of each arrangement formed by a piston or cylinder and, more generally, the mechanical properties of the sliding cover are improved;

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the central body is thermally isolated from the sliding cover by an oil cushion and an oil film;

- the axial forces are between the sliding cover and the central body by a layer of oil (cushion and / or film) transmitted, reducing the load on the crank mechanism during the engine cycle is weakened considerably.

Claims;

009041/0141

Claims (1)

Soo. d * Exploitation ί ^ ί / Γ-Εχΐ? / - ^{A 16 922 H} / ^{i: L} Ii Η76Ί11 Patent claims: 1.Liquid-cooled piston for internal combustion engines with a central body which can be coupled to a connecting rod and on which a sliding cover is arranged, which can be displaced to a limited extent in the axial direction and which, together with the central body, forms an intermediate chamber which has at least one inlet opening for the supply of a cooling liquid, preferably the lubricating oil, as well has an outlet opening for this or this, characterized in that the inlet and outlet openings in the central body (4) and the sliding hood (9) are arranged in opposite parts of the walls of the central body and the sliding hood in such a way that each Working cycle the approach of the sliding hood (9) to the central body (4) taking place under the pressure in the cylinder exceeding a control value. causes the equilateral AbeonluS the inlet and outlet openings of the intermediate buyer (12) and the chewing under the under a substantially by the dimensions de »central body · (4) and the slide (9) eowie the pressure de * Ae * tviiohenJuaaer (13 ) • run coolant tettimtea control value Druo * in SyliaUe »« iH || Mii tat * ernuif BAD ORlGINAt. - 2 - 009141/0141. - ^ - H76111 Sliding hood (9) of the middle body (4) the same- ' early opening of the inlet and outlet openings of the intermediate chambers "causes. 2 · Piston according to claim 1, the central body of which has a wall with a sliding surface and a bottom, and its sliding hood a thin wall with a sliding surface as well as having a base, characterized in that the axial movement away of the sliding hood (9) from the central body (4) by a ■ Stop washer (16) is limited, which by means of a Screw (17) on an axial through a central bore (15) in the bottom (5) of the central body (4) Extension (H) of the bottom (10) of the sliding hood (9) is attached. 5. Piston according to claim 2, characterized in that the axial approach of the sliding hood (9) to the central body (4) on the one hand by two on the outer surface of the bottom (5) of the central body (4) arranged, preferably annular, concentric, the central bore (15) surrounding contact surfaces (18, 19), and on the other hand by two on the inner surface of the bottom (10) of the sliding hood (9), the contact surfaces (18, 19) opposite, annular concentric contact surfaces (20, 21) ) is limited. 00984 1/0 U 1, " ³ " 4 · Piston according to Claims 1 and 3, characterized notched by several radially in the outer upper edge of the base (5) of the central body (4) Lubricating oil supply slots (22) for the intermediate chamber (12), which the stop surface (19) with a distribution groove (23) of the central body (4). 5. Piston according to claims 1 to 4 »characterized through an annular space calibrated by the axial extension (14) and the central bore (15) (24) for the discharge of lubricating oil from the intermediate chamber (12), as well as through discharge openings (24a) in the stop disc (16). 6. Piston according to claim 2, characterized in that that the axial approach of the sliding hood (9) · to the central body (4) by one with the Lower edge of the wall (11) of the G-guide hood (9) interacting, from the V / andung (6) of the central body (4) projecting shoulder (25) is limited. 7 · Piston according to claim 6, characterized by radially in the outer upper edge of the base (5) of the central body (4) notched lubricating oil supply slots (26) for the intermediate chamber (12), which from a distribution groove (23) of the central body (4) 009841 / 0U1 * * - - * - H76111 and a complementary distribution groove (27) of the sliding hood (9) formed directly with the intermediate chamber (12). 8. Piston according to claim 2, characterized by one of the axial extension (14) and the central bore (15) calibrated annular space (24) for the discharge of lubricating oil from the intermediate chamber (12) by a shoulder (28) provided on the axial extension (14) which has no radial play can slide in the central bore (15) can be closed. 9 «piston according to claim 4 or 7, marked a- · net by one of the fixed on the outer surfaces of the bottom (10) of the sliding hood (9) Heat loads dependent distribution of the lubricating oil supply slots (22, 26) over the circumference of the central body (4) 10. Solvent according to claim 9 for a motor provided with a cylinder head with a swirl chamber and a transfer passage , characterized in that a large number of inlet openings are provided at the location of the transfer passage (30) , the proportion of which is through the the 009S4W0U1 H76111 Place of this transfer passage (30) lying inlet openings pressure oil amount about 70 $> the total amount of pressure oil entering the intermediate chamber (12) ". 008841 / QU1