EP1394376B1 - Spray nozzle with multiple jets for cooling an internal combustion engine and engine with such nozzle - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the cooling nozzles of the pistons of an internal combustion engine, for projecting a cooling fluid such as oil on a suitable area of the piston, and the engines equipped with such nozzles.

The pistons cooling jets usually used are inserts attached to the crankcase and communicating with a coolant supply port. The position of the nozzle is accurately determined to provide a jet of cooling fluid directed to a specific area of the piston bottom or to a piston gallery entrance.

In internal combustion engines currently developed, is associated with each piston of the engine, for cooling, a cooling nozzle which projects one or more jets of cooling fluid to a single piston bottom area. For example, documents FR 2,745,329 , US 4,206,726 , EP 0 423 830 , JP 07 317519 project a single jet of coolant to the bottom of the piston. The documents DE 196 34742 and US 5,649,505 project several parallel jets to a single piston bottom area. The attachment of the nozzle in the engine cylinder can be carried out either from the outside or the inside. Thus, the documents US 5,649,505 and EP 0 423 830 describe cooling jet structures that are engaged from the outside in the engine. These nozzles lack precision because of the short length of the nozzle outlet section which is limited by the size of the nozzle introduction passage.

The document US 4,206,726 describes a nozzle whose attachment in a passage requires simultaneous access to the inside and outside of the engine cylinder.

Documents FR 2,745,329 and JP 07 317519 disclose a nozzle having a nozzle body with a penetrating portion shaped to engage axially in a bore of the housing engine and to receive the cooling fluid arriving through said bore. The nozzle has an outlet structure having a radial fluid passage in the nozzle body and having an outlet conduit adapted to direct an outlet fluid jet to the piston bottom region to be cooled.

In order to obtain good cooling, the flow rate of the jet of cooling fluid projected towards the piston bottom is appropriately selected. However, in modern internal combustion engines, whose performance is increasing, there is a need to further increase the cooling capacity of the piston portion which is closest to the gas combustion zone. It appears that the currently used nozzles limit the cooling capacity of the piston.

The evolution of engine heat requires more efficient sprinklers because the pistons are getting hotter and heavier. An attempt has been made to improve the cooling by providing, in the piston, internal galleries whose purpose is to ensure cooling closer to the combustion zone which is the hottest zone of the engine. Pistons with internal galleries are described for example in the documents FR 2,745,329 or US 4,206,726 . A gallery is a generally annular cavity in the piston, and communicates with the lower space under the piston by at least one inlet. The nozzle projects the cooling fluid into this inlet. The piston thus remains relatively thick, to withstand the mechanical stresses, and the gallery allows to bring the cooling fluid in the area that is closest to the combustion volume.

The jet must have a very high precision of the jet, because the entry of the gallery is generally about 150 millimeters from the nozzle which is fixed on the casing, and the entry of the gallery is only 5 or 6 millimeters in diameter. . In this small hole, the maximum amount of coolant must be entered. Furthermore, the nozzle must have a structure easy to manufacture, so as to be of reduced cost suitable for mass production in the automotive industry.

However known sprinkler structures are not satisfactory. For example, the document JP 07 317519 describes a one-piece molded structure with two parallel ducts and a connecting ring which is complex and expensive. The document FR 2,745,329 describes a similar one-piece conduit molded and remanufactured with a connecting ring.

The document JP 07 243313 A discloses a one-piece molded structure with two parallel ducts each connected by a radial passage to a nozzle body. The document JP 03 089908 U discloses a structure with two bent tubes each reported and fixed on a nozzle body by a respective radial passage. Such structures are complex, expensive to manufacture and not very compatible with the very small space available in an engine to place a cooling nozzle.

SUMMARY OF THE INVENTION

The problem proposed by the present invention is to design a new cooling jet structure, which can further improve the cooling capacity of the piston, for a given flow rate of cooling fluid, while remaining compatible with the very small space available in the engine to place such a cooling nozzle.

The invention also aims to design such a nozzle whose structure is particularly simple to be manufactured simply and inexpensively in large series.

The present invention results from the observation that it is certainly very good for cooling to put the maximum oil in a gallery entrance of a piston, but failures can still result from unequal distribution of the oil in the piston body.

To achieve these and other objects, the invention provides a cooling nozzle as defined by claim 1.

In a first embodiment, the outlet tube connects to the nozzle body according to the single radial passage in which the proximal end of the outlet tube is fitted and brazed.

• le premier tronçon axial de projection se termine par un premier orifice,
• le premier tube de sortie forme le premier conduit de sortie,
• le second conduit de sortie comprend un second tube de sortie, comportant un second tronçon radial de raccordement décalé angulairement à l'écart du premier tronçon radial de raccordement, se raccordant par un coude à un second tronçon axial de projection se terminant par un second orifice.

For example, we can predict that:

• the first axial projection portion ends with a first orifice,
• the first outlet tube forms the first outlet duct,
• the second outlet duct comprises a second outlet tube, comprising a second radial connection section angularly offset away from the first radial connection section, connected by an elbow to a second axial projection section ending in a second orifice .

In a second embodiment, the first outlet tube having the first orifice may comprise a larger-diameter intermediate portion to which the second outlet tube having the second orifice connects.

For example, the first outlet tube may comprise an upstream section and a downstream section connected to each other by an intermediate sleeve of larger diameter than the upstream and downstream sections, the upstream section being engaged by its respective ends in the radial passage of the nozzle body and in a first end of the sleeve, the downstream section being engaged in the second end of the sleeve, the sleeve being pierced with a lateral hole in which is engaged the upstream end of the second outlet tube.

According to another aspect of the invention, an outlet tube receives at its downstream end an outlet nozzle having two outlet orifices, the end piece having an axial inlet hole engaging on the downstream end of the outlet tube. and communicating with two divergent exit holes to be oriented toward the respective cooling zones of the piston.

According to another aspect, the invention provides an internal combustion engine comprising at least one nozzle as defined above, the nozzle being shaped and positioned so as to create and direct at least two jets of cooling fluid to two inlets. respective gallery dug in the mass of a piston.

SUMMARY DESCRIPTION OF THE DRAWINGS

• la figure 1 est une vue en perspective illustrant schématiquement une structure de piston et un gicleur associé ;
• la figure 2 est une autre vue en perspective du piston associé au gicleur selon la figure 1 ;
• la figure 3 est une vue en perspective d'un gicleur des figures 1 et 2 ;
• la figure 4 est une vue en perspective d'un gicleur selon un mode de réalisation de l'invention ;
• la figure 5 est une coupe partielle longitudinale de la structure de sortie du gicleur de la figure 4 selon une première variante;
• les figures 6 et 7 sont respectivement une coupe partielle longitudinale et une vue de dessus de la structure de sortie du gicleur de la figure 4 selon une seconde variante ;
• la figure 8 illustre un moteur ayant un gicleur produisant un premier jet projeté vers une galerie de piston et un second jet projeté vers une zone à lubrifier ;
• la figure 9 est une vue en perspective d'un gicleur selon un autre mode de réalisation de l'invention ;
• la figure 10 est une vue de face en coupe longitudinale d'un embout de gicleur de la figure 9 ;
• les figures 11 et 12 illustrent l'embout de gicleur de la figure 9, vu de dessus et de côté gauche ;
• les figures 13 et 14 illustrent des coupes longitudinales, vues de côté et de face, du gicleur de la figure 9 ;
• la figure 15 est une vue de côté d'un gicleur selon les figures 4 à 7 adapté face à un piston ; et
• la figure 16 est une vue de côté en coupe du gicleur des figures 1 à 3.

Other objects, features and advantages of the present invention will become apparent from the following description of particular embodiments, with reference to the accompanying figures, in which:

• the figure 1 is a perspective view schematically illustrating a piston structure and an associated nozzle;
• the figure 2 is another perspective view of the piston associated with the nozzle according to the figure 1 ;
• the figure 3 is a perspective view of a jet of figures 1 and 2 ;
• the figure 4 is a perspective view of a nozzle according to one embodiment of the invention;
• the figure 5 is a longitudinal partial section of the outlet structure of the jet of the figure 4 according to a first variant;
• the Figures 6 and 7 are respectively a partial longitudinal section and a top view of the outlet structure of the nozzle of the figure 4 according to a second variant;
• the figure 8 illustrates a motor having a nozzle producing a first jet projected towards a piston gallery and a second jet projected towards an area to be lubricated;
• the figure 9 is a perspective view of a nozzle according to another embodiment of the invention;
• the figure 10 is a front view in longitudinal section of a jet nozzle of the figure 9 ;
• the Figures 11 and 12 illustrate the jet nozzle of the figure 9 seen from above and from the left side;
• the Figures 13 and 14 illustrate longitudinal sections, seen from the side and from the front, of the jet of the figure 9 ;
• the figure 15 is a side view of a nozzle according to the Figures 4 to 7 adapted to a piston; and
• the figure 16 is a sectional side view of the jet of Figures 1 to 3 .

DESCRIPTION OF THE PREFERRED EMBODIMENTS

It should be noted that the cooling nozzle of Figures 1 to 3 does not correspond to the object defined by claim 1. These Figures 1 to 3 however, contribute to the general understanding of the claimed invention.

In the embodiments illustrated on the figures 4 and following, a cooling nozzle 1 according to the invention, provided for cooling a piston 8 of an internal combustion engine, comprises a nozzle body 2 having a penetrating portion 3 shaped to engage axially in an axial direction of penetration II in a bore of the motor for receiving a cooling fluid arriving through said bore as illustrated by the arrow 4. The cooling nozzle 1 further comprises a protruding outlet structure 5, communicating with the penetrating portion 3, having an axial passage of fluid from the penetrating part 3, and comprising at least one radial passage 5a (and possibly 5b) of fluid in the nozzle body 2.

In the embodiments of Figures 4 to 8 , the cooling nozzle 1 comprises at least two outlet tubes 6 and 7. Each outlet tube 6 or 7 is suitably bent to position and orient their respective outlets 16 and 17 so as to create two respective separate coolant jets 6a and 7a which are distinguished on the figures 1 , 2 and 8 and to direct the two jets 6a and 7a to two respective respective cooling zones 6b and 7b of the engine piston 8. Each outlet tube 6 and 7 is an insert by brazing and brazing, cut and formed from a drawn metal tube. This avoids having to mold and machine complex monobloc parts. And we take advantage of the very smooth and even internal surface of the drawn metal tubes, favoring a laminar flow of the fluid.

In the embodiment of the figure 4 , the first outlet tube 6 comprises a first radial connecting section 6c, generally perpendicular to the axial direction of penetration II of the nozzle in the motor body, and being connected in particular by a bend 6d to a first axial projection section 6e to first orifice 16 which thus projects the jet of cooling fluid 6a in a generally axial direction relative to the piston 8. The second outlet tube 7 comprises a second radial connecting portion 7c substantially perpendicular or substantially angular with respect to the first radial section of connection 6c, and connected by a bend 7d to a second axial projection section 7e to second orifice 17 which thus projects a jet of cooling fluid 7a in a generally axial direction, that is to say parallel to the axis of displacement of the piston 8 in the engine cylinder, the two jets of cooling fluid 6a, 7a being substantially spaced from one of the ther.

In the jet of Figures 1 to 3 , two outlet tubes 6 and 7 are connected to the nozzle body according to two separate radial passages 5a and 5b respectively of the output structure 5 by two radial connecting sections 6c and 7c. Simultaneously, the connecting radial sections 6c and 7c are substantially perpendicular to each other and both perpendicular to the axial direction II penetration. In addition, the first outlet tube 6 comprises a connecting section 6f developing in a direction generally parallel or convergent with respect to the second radial connecting portion 7c of the second outlet tube 7, and being connected angularly on the one hand to the first radial connection portion 6c by a bend 6d and on the other hand to a first axial projection section 6e by a second bend 6g, as can be seen on the figure 3 . This form of nozzle is adapted to project two jets of cooling fluid to two zones of the same piston located on either side of the median plane of the piston.

This is how we see, on the figures 1 and 2 , the cooling nozzle 1, in position in a motor facing a piston 8 biased by a rod 9 itself oscillating along the median plane MM of the piston 8 about an oscillation axis II-II. The median plane MM contains the translation axis AA of the piston 8, and is perpendicular to the axis of oscillation II-II of the connecting rod 9. The second radial connecting section 7c penetrates radially under the piston 8 towards its axis AA. The first radial connecting portion 6c bypasses the piston 8 along a portion of its circumference, then the connecting portion 6f penetrates radially under the piston 8 in the direction of its axis AA. If necessary, the skirt of the piston comprises two respective notches 8c and 8d for the passage of sections 7c and 6f.

The two jets of cooling fluid 6a and 7a produced by the cooling nozzle 1 are respectively directed towards two cooling zones 6b and 7b which are disposed on either side of the median plane MM of the piston 8. In this case, the two cooling zones 6b and 7b are two inlet openings of one or two galleries provided in the mass of the piston 8, so that the cooling fluid enters the gallery or galleries of the piston to propagate closer to the upper thrust surface 8e ( figure 15 ) of the piston, which surface receives the heat energy of the combustion gases.

Usually, the cooling nozzles are arranged in a motor in the first half-space P containing the engine intake system, for issues of size of the cooling oil supply pipes. However, the hottest parts of the engine, and therefore the piston 8, are in the second half space S containing the engine exhaust system. By providing a cooling nozzle 1 which produces two jets of cooling fluid 6a and 7a on either side of the median plane MM, it is possible to feed two gallery entrances which communicate, by a circular ring-shaped gallery, or by two respective galleries in angle ring sector less than 180 °, with two respective piston zones 8a and 8b in the half-space S. The cooling of the hottest zones 8a and 8b is thus balanced.

In the embodiment illustrated on the Figures 4 and 5 the outlet structure comprises a first outlet tube 6 which connects to the nozzle body in a single radial passage 5a. The first outlet tube 6 has the first orifice 16 and has an intermediate portion 6h of larger diameter to which is connected the second outlet tube 7 which has the second orifice 17.

In the realization more specifically illustrated on the figure 5 , the first outlet tube 6 comprises an upstream section 6c1, a downstream section 6c2, a bend 6d and an axial projection section 6e, and an intermediate sleeve 6c3 forming the intermediate section 6h of larger diameter than the upstream sections 6c1 and downstream 6c2. The upstream section 6c1 is engaged by its respective ends in the radial passage 5a of the nozzle body and in a first end of the sleeve 6c3. The downstream section 6c2 is engaged in the second end of the sleeve 6c3. The sleeve 6c3 is pierced with a lateral hole 6j in which is engaged the upstream end of the second outlet tube 7.

According to an illustrated variant on the Figures 6 and 7 , the upstream section 6c1 and the sleeve 6c3 are in one piece.

In both cases, the spacing between the two jets of cooling fluid 6a and 7a is important, but the offset of the tubes to the outside is insufficient to place the orifices 16 and 17 on either side of the median plane MM . Then place the cooling nozzle 1 with its two outlet tubes 6 and 7 on the same side of the median plane MM.

According to the invention, nozzles having more than two outlet tubes can be designed to generate more than two jets of cooling fluid.

• de garantir une grande précision du diamètre intérieur du tube, et donc de garantir une bonne précision du débit de fluide de refroidissement,
• d'améliorer la qualité du jet, produisant un jet laminaire et non diffus,
• d'augmenter la vitesse et la précision du jet en sortie du tube,
• de définir aisément les débits identiques ou différents des tubes de sortie 6 et 7, en fonction des différentes zones de piston plus ou moins prioritaires à refroidir.

In the illustrated achievements on the Figures 1 to 4 and 6 to 8, at least one of the outlet tubes 6 and 7 comprises a narrowing forming an end section 6i and 7i with reduced diameter, the technical effect of which is:

• to guarantee a high accuracy of the inside diameter of the tube, and thus to guarantee a good accuracy of the flow rate of cooling fluid,
• to improve the quality of the jet, producing a laminar and non-diffuse jet,
• to increase the speed and the precision of the jet at the outlet of the tube,
• to easily define the same or different flow rates of the outlet tubes 6 and 7, depending on the different piston zones more or less priority to cool.

To maximize the percentage of cooling fluid that enters the gallery or galleries of the piston 8, relative to the total flow through the nozzle, it is advantageous to conform the tubes of the nozzle so that the jets of cooling fluid are parallel to the AA axis of the piston 8.

However, in certain engine configurations, it is necessary to spread the nozzle radially away from the axis AA of the piston 8. It can then be found advantageous to provide that the cooling jets 6a and 7a are inclined in a radial plane according to a angle slightly falling a few degrees from the axis AA of the piston 8.

The Figures 9 to 14 illustrate a cooling nozzle having an outlet tube receiving an outlet tip for dividing the jet of cooling fluid into two jets 6a and 7a.

It should be noted that the cooling nozzle of Figures 9 to 14 does not correspond to the subject-matter of claim 1. These Figures 9 to 14 However, it is possible to illustrate the subject-matter of claims 7 and 8.

In the embodiment of Figures 9 to 14 , there is a nozzle 1 having a nozzle body 2 with a penetrating portion 3 and an outlet structure 5 radial passage 5a.

There is also a curved outlet tube 6, the first end of which is fitted into the radial hole 5a and the second end of which engages in an outlet endpiece 10.

As we see on the figure 10 , the outlet tip 10 has an axial inlet hole 10a shaped to engage on the downstream end of the outlet tube 6, and communicating with two divergent exit holes 10b and 10c intended to be oriented towards the zones of respective cooling of the piston. Thus, the two outlet holes 10b and 10c define the respective outlet orifices 16 and 17 of the cooling nozzle.

The axial inlet hole 10a may advantageously have a circular-section cylindrical shape adapted to receive the cylindrical downstream end of the outlet tube 6.

The two exit holes 10b and 10c may have different diameters, for example the outlet hole 16 may have a diameter greater than the diameter of the outlet hole 17. The diameters are chosen so as to achieve a better distribution of the outflow rates by each orifice, increasing the flow rate to water the priority areas to be cooled, and reducing the flow rate to water the lower priority areas to cool. The orientation angles of the exit holes 10b and 10c are chosen to correspond to the locations of the respective cooling zones of the piston. At their upstream end, the outlet holes 10b and 10c are closer to one another so as to communicate directly with the inside of the outlet tube 6.

The outlet tip 10 comprises, on its outer peripheral face, at least one plate 11 or 12 as illustrated in FIGS. Figures 9, 11 and 12 , the plate 11 or 12 for identifying and fixing the angular position of the outlet nozzle 10 around the outlet tube 6, for rotating the two outlet holes 16 and 17 during the mounting of the nozzle 10 on the outlet tube 6.

The outlet tip 10 may be used regardless of the presence of the other number and shape characteristics of the outlet tubes 6 and 7.

In all embodiments, the proximal ends of the outlet tubes 6 and 7 are fitted and brazed. So, the figure 16 illustrates in section the fitting of the outlet tube 7 in the radial passage 5b of the nozzle body 2, for the jet of the figure 3 . The figure 5 illustrates in section the fitting of the two tubes 6 and 7. figure 14 also illustrates the fitting of the outlet tube 6 in the nozzle body 2.

In an internal combustion engine comprising at least one cooling nozzle 1 as defined above, the cooling nozzle 1 may be shaped and positioned so as to create and direct at least two jets of cooling fluid 6a and 7a to two inlet ducts. respective galleries 6b and 7b hollowed out in the mass of a piston 8, as illustrated in FIGS. figures 1 and 2 .

A nozzle according to Figures 4 to 7 can project two jets of cooling fluid to two zones 6b and 7b located on the same side of the median plane MM, or to two zones 6b and 7b on either side of the plane MM. In the latter case the efficiency is reduced because the connecting rod 9 momentarily cuts the jet 7a during a portion of its travel cycle.

The present invention is not limited to the embodiments which have been explicitly described, but it includes the various variants and generalizations thereof within the scope of the claims below.

Claims (13)

1. Cooling nozzle (1) for cooling a piston (8) of an internal combustion engine, the nozzle including a nozzle body (2) having a penetrating portion (3) conformed to be engaged axially in a bore in the engine in an axial penetration direction (I-I) and to receive a cooling fluid arriving via said bore, and the nozzle including an outlet structure (5) having at least one first outlet passage and one second outlet passage adapted to direct toward the piston (8) to be cooled at least two separate jets (6a, 7a) of cooling fluid,
   characterized in that :

   - the outlet structure (5) comprises a single radial passage (5a) in the nozzle body (2),

   - a first outlet tube (6) is connected to the sprayer body (2) by a single radial passage (5a),

   - the first outlet tube (6) includes a first radial connecting section (6c) generally perpendicular to the axial penetration direction (I-I), connected by an elbow (6d) to a first axial spraying section (6e),

   - the first outlet tube (6) receives an attached element (7 ; 10) allowing to separate the cooling fluid jet into two jets (6a, 7a).
2. Cooling nozzle according to claim 1, characterized in that the outlet tube (6) is connected to the nozzle body (2) by the single radial passage (5a) in which proximal end of the outlet tube (6) is force fitted and brazed.
3. Cooling nozzle according to either of claims 1 and 2, characterized in that :

   - the first axial spraying section (6e) ends by a first orifice (16),

   - the first outlet tube (6) forms the first outlet passage,

   - the second outlet passage comprises a second outlet tube (7) including a second radial connecting section (7c) offset angularly away from the first radial connecting section (6c) and connected by an elbow (7d) to a second axial spraying section (7e) terminating at a second orifice (17).
4. Cooling nozzle according to claim 3, characterized in that the first outlet tube (6) including the first orifice (16) has a larger diameter intermediate section (6h) to which the second outlet tube (7) including the second orifice (17) is connected.
5. Cooling nozzle according to claim 4, characterized in that the first outlet tube (6) has an upstream section (6c1), a downstream section (6c2), and an intermediate sleeve (6c3) of larger diameter than the upstream section (6c1) and the downstream section (6c2), the upstream section (6c1) having its respective ends engaged in the radial passage (5a) in the sprayer body (2) and in a first end of the sleeve (6c3), the downstream section (6c2) being engaged in the second end of the sleeve (6c3), and the sleeve (6c3) including a lateral bore (6j) in which the upstream end of the second outlet tube (7) is engaged.
6. Cooling nozzle according to any one of claims 1 to 5, characterized in that at least one of the outlet tubes (6, 7) includes a constriction forming a smaller diameter end section (6i, 7i).
7. Cooling nozzle according to either of claims 1 and 2, characterized in that the outlet tube (6) is connected to an outlet end-piece (10) including the two outlet orifices (16, 17), the end-piece (10) having an axial inlet hole (10a) force fitted over the downstream end of the outlet tube (6) and communicating with two diverging outlet holes (10b, 10c) adapted to be oriented toward the respective cooling areas (6b, 7b) of the piston (8).
8. Cooling nozzle according to claim 7, characterized in that the outlet end-piece (10) has on its external peripheral surface at least one flat (11, 12) for identifying and fixing the angular position of the outlet end-piece (10) around the outlet tube (6).
9. Internal combustion engine, characterized in that it includes at least one nozzle (1) according to any one of claims 1 to 8, conformed and positioned so as to create and direct at least two jets (6a, 7a) of cooling fluid toward two respective tunnel inlets (6b, 7b) hollowed into the mass of a piston (8).
10. Engine according to claim 9, characterized in that the jets (6a, 7a) of cooling fluid are parallel to the axis (A-A) of the piston (8).
11. Engine according to claim 9, characterized in that the jets (6a, 7a) of cooling fluid are inclined in a radial plane at a slightly re-entrant angle of a few degrees with respect to the axis (A-A) of the piston (8).
12. Engine according to any one of claims 9 to 11, characterized in that the two tunnel inlets (6b, 7b) each communicate with a respective tunnel in the shape of a sector of a ring subtending an angle of less than 180°.
13. Engine according to any one of claims 9 to 11, characterized in that the two tunnel inlets (6b, 7b) communicate with the same ring-shaped tunnel.

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