EP1273774B1 - Nozzle for piston cooling - Google Patents

Abstract

The cooling nozzle for an engine piston comprises a body (1), with a penetrating part which engages in an engine bore, receiving coolant fluid. The nozzle comprises an internal valve composed of a piston (6) which slides in a guide bore (9). The piston comprises a sealing head (10) directed upstream and supported against an annular seat (11). The piston is pushed toward the seat by a helical compression spring (13).

Description

The present invention relates to the cooling nozzles of the pistons of an internal combustion engine, for projecting a cooling fluid such as oil against the piston bottom, that is to say against the outer piston face to the explosion chamber, or in a piston gallery.

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

The cooling nozzles generally include a valve, for inhibiting the circulation of cooling fluid until the pressure of the cooling circuit has exceeded a determined threshold value.

Spray structures are generally used, the valve of which is made by a ball, pushed by a compression spring towards a seat to close a passage of cooling fluid. These structures are short and compact.

The inventors have found that the valve cooling nozzles used until now function properly and are satisfactory for a limited time, after which time appear phenomena of wear that disturb the sealing of the valve and its proper operation. The correct operating time is shorter as the nominal pressure of the coolant in the cooling lines is high. The wear mainly modifies the opening characteristics of the valve, ie the fluid pressure necessary to trigger it: at nine, the valve opens at a correct nominal pressure; after wear, the valve opens at a lower pressure, up to half the correct nominal pressure, therefore below the idle speed of the engine. This results in a disturbance of the general pressure of the fluid in the engine.

The invention results from the observation that the phenomena of wear are inevitable because of the very structure of the ball valve: under high pressure, there are phenomena of oscillation and vibration of the ball, phenomena that cause wear defects.

Also known from JP 07 317519 A nozzle for engine cooling, the valve comprises a piston pushed against a seat by a spring and sliding in an axial bore communicating with a radial fluid passage. The structure is long and cumbersome, because the opening of the valve requires to move and guide the piston downstream of the radial fluid passage.

The problem proposed by the present invention is to design a new valve sprinkler structure, capable of functioning properly for a significantly longer period, in particular without significant wear.

Surprisingly, according to the invention, it is advantageous to replace the ball valve with a piston valve. Under similar conditions of high pressure, a piston valve does not have the disadvantages of oscillation and vibration of the ball valves, so that satisfactory use can be achieved for a much longer period of time.

Another problem that the invention proposes to solve is to reduce the size of the nozzle in the engine cylinder. Indeed, the piston valves of JP 07 317519 A lead to a relatively large size, and in particular a relatively large length downstream of the valve outlet orifices for guiding the piston. Too long a length downstream of the outlet ports of the valve is a risk of collision with the rotating elements of the engine such as the crankshaft or against the weight of crankshaft.

Thus, the invention aims to reduce the total length of the nozzle, and in particular the nozzle length protruding into the engine cylinder downstream of the outlet radial fluid passage structure and outlet tube.

To achieve these and other objects, the invention provides a piston cooling nozzle of an internal combustion engine, having a penetrating nozzle body shaped to engage a bore of the engine and to receive a coolant fluid arriving through said bore, having an internal valve for modulating the fluid flow rate as a function of its pressure, and having a radial fluid passage outlet structure in the nozzle body and outlet tube, adapted to transmit the cooling fluid exiting the inner valve and for directing it against the bottom of the engine piston to be cooled; the internal valve comprises a piston, having a downstream section with a cylindrical lateral guide surface engaged longitudinally in a guide bore integral with the nozzle body, having a closure head oriented upstream in the direction of flow of the cooling fluid to come wear selectively against an annular sealing seat secured to the nozzle body and traversed by the cooling fluid, and the inner valve comprises a helical compression spring, axially engaged between a downstream surface integral with the nozzle body and a downstream surface of the piston for biasing the piston upstream against the annular sealing seat.

Such a structure has a great endurance, a great stability, which reduces the oscillations and very substantially reduces the phenomena of wear.

According to the invention, the guide bore in which the piston slides is essentially inside an upstream section of the nozzle body, upstream of the radial fluid passage, and fluid conduction passages axially conduct the fluid. from the downstream of the annular sealing seat to the radial fluid passage as soon as the piston moves away from the annular closure seat, so that, in the open state of the internal valve, the piston is essentially in upstream of the radial fluid passage.

It is advantageous to provide that the downstream piston section comprises a downstream coaxial housing in which engages and is guided the upstream end portion of the coil compression spring.

In a first embodiment, the nozzle body comprises a through axial bore, in which is engaged without play and held in position a tubular liner with axial bore, a downstream section forms the guide bore receiving the downstream piston section, the jacket tubular having an internal intermediate shoulder forming the annular sealing seat, at least one radial hole being provided in the tubular liner wall immediately downstream of the annular sealing seat to conduct the fluid radially towards one or more peripheral passages provided between the outer surface of the tubular liner and the surface of the axial through bore of the nozzle body, said peripheral passages being adapted to axially drive the coolant from the radial hole (s) to the radial fluid passage in the jet body . In this way, in the open state of the valve, the piston is upstream of the radial fluid outlet passage.

For example, the peripheral passage or passages are made by a larger diameter axial through-bore section, while the tubular liner has a substantially constant outer diameter leaving an annular intermediate space through which the cooling fluid flows.

Preferably, the tubular liner is made of sintered steel, while the piston is made of steel. This considerably promotes sliding between the piston and the liner, thus reducing the phenomena of wear and the risk of galling.

According to another embodiment, the piston comprises, between its downstream section with cylindrical lateral guide surface and the closure head, an external annular recess defining, with the wall of the guide bore, an annular housing communicating by radial holes. piston piston with an axial piston bore open downstream in the axial through bore of the body which conducts the cooling fluid to the radial fluid passage in the nozzle body. In this way, in the open state of the valve, the piston is clearly upstream of the radial fluid outlet passage.

The annular sealing seat may be an annular ring reported in the axial bore passing through the nozzle body.

• la figure 1 est une vue en perspective éclatée d'une structure de gicleur selon un premier mode de réalisation de la présente invention ;
• la figure 2 est une vue en perspective en section partielle du gicleur de la figure 1, assemblé ;
• la figure 3 est une vue de face en coupe longitudinale du gicleur des figures 1 et 2, illustrant le fonctionnement ;
• la figure 4 est une vue en perspective éclatée d'un gicleur selon un second mode de réalisation de la présente invention ;
• la figure 5 est une vue en perspective en section partielle du gicleur de la figure 4, assemblé ;
• la figure 6 est une vue de face en coupe longitudinale du gicleur des figures 4 et 5, illustrant le fonctionnement ; et
• la figure 7 illustre un gicleur selon l'invention incorporé dans un moteur à combustion interne.

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:

• Figure 1 is an exploded perspective view of a nozzle structure according to a first embodiment of the present invention;
• Figure 2 is a perspective view in partial section of the nozzle of Figure 1, assembled;
• Figure 3 is a longitudinal sectional front view of the nozzle of Figures 1 and 2, illustrating the operation;
• Figure 4 is an exploded perspective view of a nozzle according to a second embodiment of the present invention;
• Figure 5 is a perspective view in partial section of the nozzle of Figure 4, assembled;
• Figure 6 is a longitudinal sectional front view of the nozzle of Figures 4 and 5, illustrating the operation; and
• Figure 7 illustrates a nozzle according to the invention incorporated in an internal combustion engine.

In both embodiments illustrated in the figures, a piston cooling nozzle for an internal combustion engine comprises a nozzle body 1, an internal valve 2, and an outlet structure 3 adapted to transmit the cooling fluid exiting the valve. and to direct it in jet at least against the bottom of a piston to cool.

The nozzle body 1 comprises a penetrating portion 4, shaped to engage in a bore of the engine and to receive a cooling fluid arriving through said bore of the engine. The nozzle body 1 has a projecting portion 5, intended to protrude into the engine cylinder and to carry the outlet structure 3.

In both embodiments, the internal valve 2 comprises a piston 6, having a downstream section 7 with a lateral cylindrical guide surface 8 engaged longitudinally in a groove. guide bore 9 secured to the nozzle body 1. The piston 6 comprises a closure head 10, directed upstream in the direction of flow of the cooling fluid to come selectively to bear against an annular closure seat 11 secured to of the nozzle body 1 and having a seat bore 12 to be traversed by the cooling fluid.

The internal valve 2 further comprises a helical compression spring 13, engaged axially between a downstream bearing 14 secured to the nozzle body 1 and a downstream surface 15 of the piston 6, to bias the piston 6 upstream against the annular seat of the piston. shutter 11.

It is understood that, in its displacements along the longitudinal axis II of the nozzle, the piston 6 is perfectly guided, which avoids any risk of oscillation and instability, so that the nozzle has a greater endurance and lower wear.

The outlet structure 3 comprises at least one radial fluid passage 17 in the nozzle body 1, and at least one outlet tube 18 having a first end fitted into the corresponding radial fluid passage 17.

The piston 6 slides in the guide bore 9 inside an upstream section 16 of nozzle body 1, upstream of the radial fluid passage 17, between a valve closing position and an opening position of valve. In the valve opening position, the piston 6 remains essentially upstream of the radial fluid passage 17.

Thus, the piston sliding sealingly in the guide bore 9 is opposed a priori to the passage of fluid between the annular sealing seat 11 and the radial fluid passage 17. To ensure the passage of the fluid, the invention provides, in either of the illustrated embodiments, fluid conduction passages leading the fluid axially from the downstream of the annular sealing seat 11 to the radial fluid passage 17 as soon as the piston s The fluid conduction passages will be described hereinafter and have different structures in either of the illustrated embodiments.

To use a compression coil spring 13 of great length without increasing the length of the protruding part 5 of the nozzle in the engine cylinder, the downstream section 7 of the piston 6 has a coaxial housing downstream 19 in which engages and is guided the part Upstream end 20 of the compression coil spring 13.

In both embodiments, the nozzle body 1 comprises a through axial bore 21, along the axis I-I of the nozzle body 1, in which the piston 6 slides axially.

In the embodiment of Figures 1 to 3, a tubular liner 22 is engaged without play and held in position in the axial through bore 21, in the protruding portion 5 of the nozzle, being engaged between a downstream plug 39 and a ring 40. The tubular liner 22 comprises an axial bore 23, a downstream portion of which forms the guide bore 9 receiving the downstream portion of the piston 6.

The tubular liner 22 comprises an internal intermediate shoulder forming the annular sealing seat 11.

At least one radial hole 24 is provided in the wall of the tubular liner 22, immediately downstream of the annular sealing seat 11, for radially conducting the fluid to one or more peripheral passages provided between the outer surface of the tubular liner 22. and the surface of the axial through bore 21 of the nozzle body 1. The peripheral passages 25 are adapted to axially drive the cooling fluid from the radial hole (s) 24 to the radial fluid passage 17 in the nozzle body 1 .

In this way, the piston 6 can be arranged permanently upstream of the radial fluid passage 17 in the nozzle body 1, and the protruding portion 5 can thus have a reduced volume.

In the embodiment illustrated in FIGS. 1 to 3, the peripheral passages 25 are made by a through-bore axial bore section 21 of larger diameter, while the tubular liner 22 has a substantially constant outer diameter, leaving an annular intermediate space by which flows the cooling fluid.

In this same illustrated embodiment, the tubular liner 22 may advantageously be made of sintered steel, while the piston 6 is made of steel. This results in a very low coefficient of friction, and good lubrication between the piston 6 and the tubular liner 22, facilitating piston movements without wear and reducing the risk of galling.

This first embodiment further promotes the stability of the valve, in that the valve is subjected upstream to the cooling fluid pressure, while it is subjected downstream only to the air pressure and to the return force of the spring. The valve is either open when the fluid pressure is greater than the spring force, or closed in the opposite case, but never vibrates between the two positions.

In the embodiment of Figures 4 to 6, there is a nozzle body 1 having the same essential means as those of the previous embodiment, these means being identified by the same reference numerals, so that it is superfluous to describe again. Reference is made to the drawings for this purpose.

In this second embodiment, the piston 6 comprises, between its downstream section 7 with lateral cylindrical guide surface 8 and the closure head 10, an external annular recess 26 defining, with the wall of the guide bore 9, an annular housing communicating by radial piston holes 27 with an axial bore of piston 28 open downstream in the axial through bore 21 of the body which conducts the cooling fluid to the radial fluid passage 17 in the body of jet 1.

This second structure also makes it possible to place the piston 6 permanently upstream of the radial fluid passage 17 in the nozzle body 1, by ensuring the axial conduction of the fluid from the annular sealing seat 11 to the radial fluid passage 17 .

In the first embodiment of Figures 1 to 3, there is provided a vent 29 downstream of the housing containing the compression coil spring 13, the vent 29 allowing the passage of air into and out of the spring housing during the movements of the piston 6. The vent 29 is formed in the downstream plug 39.

On the other hand, in the second embodiment of FIGS. 4 to 6, it is not necessary to provide a vent downstream of the helical compression spring 13, the fluid escaping being effected by the cooling fluid conduction passages. .

In this same second embodiment, the annular sealing seat 11 is an annular ring 30, attached in the axial through bore 21 of the nozzle body.

The operation of the nozzle is explained in Figures 3 and 6.

The cooling fluid arrives through the upstream end 31 in a bore of the engine block. When the pressure of the cooling fluid is greater than a predetermined threshold, the fluid pushes the piston 6 against the return force exerted by the compression coil spring 13, so that the cooling fluid can pass between the shutter head 10 and the annular shutter seat 11.

In the embodiment of FIG. 3, the cooling fluid passes radially through the radial holes 24, then axially along the peripheral passages 25, to reach the radial fluid passage 17 and exit through the outlet tubes 18.

In the embodiment of Figure 6, the cooling fluid passes between the annular sealing seat 11 and the sealing head 10, is distributed in the outer annular recess 26, passes radially towards the center by the radial holes piston 27, then moves axially in the axial piston bore 28 and in the axial through bore 21 of the body which conducts the cooling fluid to the radial fluid passage 17 and the outlet tube 18.

Figure 7 illustrates the implantation of a nozzle according to the invention in an internal combustion engine. The figure illustrates a motor part, comprising a motor half-cylinder.

The nozzle 32 is attached to the wall of the cylinder housing 33, inside the engine, to take cooling fluid circulating in a cooling pipe 34 and to project the cooling fluid into the cylinder motor against the bottom 35 of the engine piston 36, that is to say against the face of the engine piston which is external to the explosion chamber 37.

The penetrating portion 4 of the nozzle 32 is engaged in a corresponding bore of the cylinder housing 33, communicating with the cooling pipe 34. The nozzle is thus fixed by any known means, for example force-fitted or screwed into the corresponding bore of the Cylinder case 33. The protruding portion 5 of the nozzle 32 protrudes into the interior of the engine cylinder. There is an outlet tube 18, which is bent so that its outlet orifice 38 is directed upwards against the bottom 35 of the piston 36.

An internal combustion engine can thus advantageously comprise piston cooling nozzles according to the invention, as described above, fixed in the piston chamber or chambers and adapted to each project the cooling fluid in a concentrated jet against the bottom of the piston. 'A piston.

The present invention is not limited to the embodiments that have been explicitly described, but includes the various variants thereof.

Claims (8)

1. Nozzle (32) for cooling a piston (36) of an internal combustion engine, including a nozzle body (1) with a penetrating part (4) shaped to engage in a bore of the engine and to receive a cooling fluid arriving via said bore, including an internal valve (2) for modulating the flow of fluid as a function of its pressure, and including an outlet structure (3) with a radial fluid passage (17) in the nozzle body (1) and an outlet tube (18), adapted to transmit cooling fluid leaving the internal valve (2) and to direct it in the form of a jet at least against the back (35) of the piston (36) to be cooled, the internal valve (2) including a piston (6), having a downstream section (7) with a cylindrical lateral guide surface (8) sliding longitudinally in a guide bore (9) in the nozzle body (1), having a head (10) oriented in the upstream direction defined with respect to the direction of flow of the cooling fluid to bear selectively against an annular seat (11) in the nozzle body (1) and through which the cooling fluid flows, and the internal valve (2) including a compression coil spring (13), engaged axially between a downstream bearing surface (14) in the nozzle body (1) and a downstream surface (15) of the piston (6) to urge the piston (6) in the upstream direction against the annular seat (11),
   characterized in that the guide bore (9) in which the piston (6) slides is essentially inside an upstream section (16) of the nozzle body (1), on the upstream side of the radial fluid passage (17), and fluid passages (24, 25 ; 26, 27, 28) convey the fluid axially from the downstream side of the annular seat (11) to the radial fluid passage (17) as soon as the piston (6) moves off the annular seat (11), so that, when the internal valve (2) is open, the piston (6) is substantially on the upstream side of the radial fluid passage (17).
2. Cooling nozzle according to claim 1, characterized in that the downstream section (7) of the piston (6) includes a downstream coaxial portion (19) in which the upstream end part (20) of the compression coil spring (13) is engaged and guided.
3. Cooling nozzle according to claims 1 or 2, characterized in that the nozzle body (1) has an axial through bore (21), in which is engaged without clearance and retained in position a tubular jacket (22) with an axial bore (23), a downstream section of which forms the guide bore (9) receiving the downstream section of the piston (6), the tubular jacket (22) having an internal intermediate shoulder forming the annular seat (11), at least one radial hole (24) being provided in the wall of the tubular jacket (22) immediately downstream of the annular seat (11) to convey fluid radially towards one or more peripheral passages (25) between the external surface of the tubular jacket (22) and the surface of the axial through bore (21) of the nozzle body (1), said peripheral passages (25) being adapted to convey cooling fluid axially from the radial hole or holes (24) to the radial fluid passage (17) in the nozzle body (1).
4. Cooling nozzle according to claim 3, characterized in that the peripheral passage or passages (25) comprise a larger diameter section of the axial through bore (21), whereas the tubular jacket (22) has a substantially constant outside diameter leaving an annular intermediate space in which the cooling fluid flows.
5. Cooling nozzle according to claims 3 or 4, characterized in that the tubular jacket (22) is made of sintered steel, while the piston (6) is made of steel.
6. Cooling piston according to claims 1 or 2, characterized in that the piston (6) includes, between its downstream section (7) with its cylindrical lateral guide surface (8) and the head (10), an external annular recess (26) defining, with the wall of the guide bore (9), an annular housing communicating via radial piston holes (27) with an axial piston bore (28) open in the downstream direction into the axial through bore (21) of the body that conveys the cooling fluid to the radial fluid passage (17) in the nozzle body.
7. Cooling nozzle according to claim 6, characterized in that the annular seat (11) is an annular ring (30) fixed into the axial through bore (21) of the nozzle body (1).
8. Internal combustion engine including at least one nozzle incorporating a piston as claimed in any one of claims 1 to 7.

Images