JP6855582B2 - High pressure accumulator for fuel high pressure injection system - Google Patents

Description

The present invention relates to a high pressure accumulator of a high pressure injection system formed from a cylinder defining a high pressure chamber and a connection piece, the connection piece being placed downstream with an outlet passage for a high pressure liquid leading to the chamber. It is equipped with a throttle for weakening the pressure wave generated by the nachgesthetet.

Such high pressure accumulators for the high pressure injection system shown in FIG. 7 are already known. The rail 100, also referred to as a "high pressure accumulator," is formed by a cylinder 111 made of thick forged steel that surrounds the high pressure chamber 112. The main body of the rail has an outlet connection piece (AustritsAnchrussture) 113 for connecting a high-pressure pipe connected to an injector, respectively. A hole 114 leading to the chamber 112 crosses the connection piece 113. At the bottom of the hole at the connection with the chamber is a throttle 115 drilled. The throttle 115 damps the pressure wave generated in the high pressure liquid on the rail by the closing motion of the injector assigned to each connection piece. The throttle 115 created by drilling is sometimes called a "nozzle".

Although this solution makes it possible to dampen pressure waves, this solution has some drawbacks, especially the drilling that creates this throttle is ausarbeiten geometry. The effect of this solution is relatively small, as it does not allow the creation of geometry.

It is also not possible to comply with strict tolerances. In addition to this, finishing in the shape of a hole at a level where the passage opens into the chamber creates an edge that produces a strong dispersion as the wave is dampened. To avoid this, the edges of the hole openings need to be electrochemically treated to round the edges and, in some cases, to remove existing burrs or protrusions within the chamber. However, this is a relatively difficult and therefore expensive process.

In the prior art, there is also a nozzle type that is inserted as an alternative to the nozzle that is bored in the rail. These nozzles are inserted as conventional, i.e. by the dominance of negative geometric play (shape-coupling tightening) and the use of press verband, where the insertion force is controlled. Will be done. This plug-in nozzle is only used for rails that do not autoflet or slightly autofregate. This is because autofrettes result in residual deformation that jeopardizes the control of shape-coupling tightening. In such cases, it may be necessary to perform an expensive additional post-treatment step on the insertion diameter after autofretted. Therefore, this known solution has a number of drawbacks.

The object of the present invention is to make it possible to effectively attenuate the pressure wave generated by closing the injection valve of the injector placed on the downstream side in the rail, and at the same time, it can be easily created and the same rail or the same rail. It is the development of high pressure accumulators in high pressure injection systems that produce weakly damped dispersions between nozzles on different rails.

For this purpose, the present invention relates to a high pressure accumulator for a high pressure injection system of an internal combustion engine, which is formed of a cylinder defining a high pressure chamber and a connecting piece. One or more splices provide one or more outlet passages for the high pressure liquid leading to the chamber. A throttle is arranged in the outlet passage to weaken the pressure wave of the injector placed on the downstream side. At the outlet, each connecting piece comprises a passage with a chamber, which houses an insert with a throttle. The inserts are force-coupledly arranged in the chamber by the autofretage process of the high pressure accumulator.

The high pressure accumulator according to the invention is easy to manufacture and nevertheless has a throttle with low tolerances. The tight connection of the insert in the high pressure accumulator is done easily and without the need for new or alternative means. This is because this tight connection is made by the rail autofletage. Rail autofletage is a known manufacturing process for ensuring rail fatigue behavior. This does not lengthen the manufacturing cycle.

Throttles made on the outside of the rail are simple because the drilling and finishing steps on the outside of the rail do not run the risk of foreign matter being introduced into the rail and avoid burr problems. Enables manufacturing. On the contrary, this makes it possible to create smooth edges or roundness.

Therefore, the passage of the insertion piece has a rounded opening on the high pressure chamber side.

According to another advantageous feature, the passage in the insert is a stepped hole formed from a row of holes with progressively smaller diameters separated by a conical function. This allows for a stepped throttle that allows the insert to be more optimized with respect to the attenuation / loss compromise of system effectiveness.

A row of holes with progressively smaller diameters is just one example of the complex geometry made possible by nozzles that are machined separately from the rails. The purpose is to obtain pressure drop asymmetry, i.e., to reduce the pressure drop in the direction beneficial for injection and to increase the pressure drop in the direction that contributes only to damping.

According to another feature, the passage with the throttle has a conical inlet that forms a seal seat for the autofretage process.

According to another feature, the connecting piece again has a conical inlet to create a hermetic seal for autofletage.

According to a more special feature, the chamber is cylindrical and forms a shoulder with a hole, which shoulder creates a sealing edge.
The insert has an outer surface with a large diameter cylindrical portion to allow play during assembly to enter the cylindrical chamber. Further, the insert has a small diameter portion that projects freely within the hole of the connecting piece, and the two parts of the insert are connected by a conical segment defined to hit the edge of the connecting piece. ..

According to another feature, the connecting piece has a conical chamber, which is followed by a hole having a cross section smaller than the cross section of the bottom of the conical chamber. And the insert with throttle has a cone with a length shorter than the length of the conical chamber, the cross section of the truncated cone of the cone is larger than the cross section of the truncated cone of the chamber, and the cone degree and cone of the chamber. Is the same as the conical degree of.

In the case of a conical chamber, the surface of the conical chamber and / or the surface of the conical body is non-uniform, in order to improve the adhesion of the two surfaces that come into contact with each other due to the truncated cone, and also to improve the sealing during the truncated cone. It is advantageous to have unevenness and a raised or recessed geometry.

According to another feature, the cross-section of the portion of the insert that enters the hole is smaller than the cross-section of the hole so that it does not come into contact with the hole after the rail and the auto-fletage of the insert.

In this way, the connection area between the insert and the connection is reduced by the only contact surface that can be spanned by the autofletage.

According to another feature, the length of the portion of the insert is shorter than the length of the hole so that the opening of the throttle is significantly away from the opening of the hole in the chamber. This causes the outlet of the insert hole to be located far above the hole opening in the chamber, affecting pressure loss.

When the high-pressure accumulator has a plurality of connection pieces, it is preferable that the insertion piece with a throttle according to one of the above-described embodiments is arranged in each connection piece leading to the injector placed on the downstream side.

The subject of the present invention is also the manufacture of a high pressure accumulator as defined above, the method of which is characterized by:
-Milling creates a chamber in the outlet passage of each connecting piece,
− An insert across the throttle is created, the outer diameter of the insert is adapted to the outer diameter of the chamber,
-Insert pieces are placed in each chamber
-The tightness of the insert and the tightness of the inlet of the connecting piece are created.
-The rail thus assembled is exposed to autofretage pressure to process the inner surface of the rail and force-coupledly place the insert in the chamber of the connecting piece.

As mentioned above, the method of manufacturing rails is particularly simple and at the same time offers the advantage of being able to create accurate and effective throttles for dampening pressure waves (pressure impacts).

It is an axial sectional view of a part of the high pressure accumulator of a high pressure injection system. FIG. 5 is an axial cross-sectional view of an insert having a throttle for the high pressure accumulator of FIG. It is a schematic semi-cross-sectional view of the embodiment of the high pressure accumulator of FIG. FIG. 5 is an axial cross-sectional view of another embodiment of the high pressure accumulator of the injection system according to the present invention. FIG. 4 is an axial cross-sectional view of an insert having a throttle for the high pressure accumulator of FIG. It is a half cross-sectional view explaining the assembly of the insertion piece which has a throttle in the connection piece of the high pressure accumulator of FIG. It is a cross-sectional view of a known rail or a high pressure accumulator.

Hereinafter, the present invention will be described in detail based on the examples shown in the accompanying drawings.

According to FIG. 1, the present invention relates to a rail or a high pressure accumulator 1 of a high pressure injection device in an internal combustion engine. A customary portion of this rail is shown in an axial cross section. Other components of the injection facility are not shown.

The high-pressure accumulator 1 is a thick cylindrical body 11 made of forged steel, and the cylindrical body is a high-pressure fuel by a high-pressure pump to distribute the high-pressure fuel to an injection valve (injector) controlled by a central control unit of the engine. Surrounds the high pressure chamber 12 to which is supplied.

The compression and expansion waves (“pressure impacts”) that are transmitted by the high-pressure liquid into the pipe connecting the injector to the rail 1 and thus reach the rail cause the injector to close and open.

The cylindrical body 11 has a connecting piece 13 for connecting, and each of these connecting pieces is connected to the high pressure chamber 12 by a passage 131 and is connected to an injector by a high pressure pipe. The connection piece has a thread 132 on the outside for screwing the connection portion of the high pressure pipe.

The example of FIG. 1 only shows a conventional portion of a rail with two connecting pieces 13 having one empty and the other having a throttled insert 2. Rail 1 has exactly the same number of connection pieces 13 and high pressure fuel outlets as the injectors supplied. It is preferable that all of these connection pieces 13 have the same structure, and only one of these connection pieces will be described below.

The connection piece 13 on the right side of FIG. 1 shows a passage 131 without the insertion piece 2 with a throttle, and the connection piece 13 on the left side includes an insertion piece 2 with a throttle.

In FIG. 2, the insertion piece 2 with a throttle is shown separately in a cross-sectional view.

According to FIG. 1, in the connecting piece 13, the passage 131 is formed in the direction extending from the inlet cone 1311 toward the high pressure chamber 12. The inlet cone is followed by a cylindrical chamber / hole 1312 having a diameter greater than the diameter of the postpositioned hole 1314 to form the seal edge 1313. The passage 131 accommodates the insertion piece 2 with a throttle.

According to FIG. 2, the insertion piece 2 with a throttle has a cylindrical body 21 with which the step hole 22 crosses, and the step hole is a row of holes having a diameter gradually decreasing, separated by a conical connecting portion 223 and 225. It is made up of 222, 224, and 226. The inlet of the insert 2 has a conical shape 221 that creates a seal seat, and the opening of the last hole 226 leading to the chamber of the rail has a rounded edge or a rounded 227.

The step hole 22 forms a throttle defined to weaken the pressure waves (compression and expansion) introduced into the high pressure liquid by the closing and opening motions of the injector.

The body 21 of the insert piece having the outer surface 23 of the insert piece 2 is connected to a portion of the small cross section 233 by a conical connection 232 that forms a support surface to cooperate with the edge 1313 of the passage 131 of the connection piece. It has a portion of cross section 231. The outer surface 23 of the small cross-sectional portion 233 ends with a roundness 234. The large diameter of the portion 231 of the insertion piece 2 is slightly smaller than the diameter of the hole 1312 of the connecting piece 13. The small diameter of the portion 233 is much smaller than the diameter of the hole 1314 post-installed after the hole 1312 of the connection piece 13, in which case the insertion piece 2 with the throttle is inserted into the passage 131 of the connection piece 13 for assembly. The small cross-sectional portion 233 does not come into contact with the wall of the passage 131, especially its hole 1314. Although the step holes 1312/1314 are not required for hydraulic function, the step holes allow the diameter of the holes to be reduced at levels that intersect the high pressure chamber 12. The length of the portion 233 of the insert 2 is shorter than the length of the hole 1314 so that the opening of the throttle 226 is significantly separated from the opening 1315 of the hole 1314 of the chamber 12.

This description of the length of the holes in the insert piece and the connection piece can also be applied to the second embodiment described below.

The locking of the insert 2 or the force-coupling arrangement of the inserts is performed by autofletage as described below.

According to the half-section view of FIG. 3, when the rail 1 includes all the insertion pieces 2 with throttles, the rails are auto-fletaged. Therefore, each connecting piece 13 is attached with a closed body (Verschrus) (not shown) with respect to the conical seat (konischer Sitz) 221 of the insertion piece 2. In this way, an Auflage is created. The tightening force (Spankraft) F applied at the axis xx during autofletting is the tightness (zone A) of the insert piece 2 and the conical surface 232 of the insert piece 2 and the edge 1313 of the connecting piece 13 in the zone B. The contact with the insertion piece 2 also creates a seal between the insertion piece 2 and the passage 131.

This limits the surfaces of the Bohrung 131 and the insert 2 that will be exposed to the high pressure of the liquid autofretage introduced into the rail.

The surface thus exposed was placed in front of the contact between the conical shoulder 232 (in the outflow direction of the high pressure fuel) and the edge 1313 that separates the holes 1312 and 1314 of the connecting piece 13. , The surface of the chamber 12 placed in front of the insertion piece 2 including the inner surface and the outer surface of the insertion piece 2, and the surface of the passage 131 of the connection piece 13. In other words, the surfaces opposite the insert 2 and the hole 1312 are subject to the forces generated by this high pressure rather than being exposed to the high pressure liquid of the autofretage. Thus, a very high autofledge pressure plasticizes the inner layer of the exposed surface of the rail 1 and the insert piece 2, which is deformed and pressed into the hole 1312 of the connecting piece 13. When this very high autofledge pressure is applied, the connecting piece 13 contracts toward each insertion piece 2, whereby the connecting piece contracts.

FIG. 4 shows another embodiment of the rail 1a according to the invention, which remains in the same conventional portion as a rail with two connecting pieces 13a, one empty and the other having a throttled insert 2a. Is shown. All of these connection pieces 13a preferably have the same structure, in which case only one of these connection pieces will be described.

In FIG. 5, the insertion piece 2a with a throttle is shown separately in cross-sectional view.

According to FIG. 4 and the orientation extending towards the high pressure chamber 12a, in the connecting piece 13a, a passage 131a is formed from the inlet cone 1311a, followed by the cone chamber 1312a, and the bottom of the cone chamber is It has a diameter larger than the diameter of the post-installed hole 1314a to form the edge 1313a. The conical chamber 1312a forms a "Mosekonus" or equivalent cone type insertion chamber. The passage 131a accommodates a complementary shaped insertion piece 2a with a throttle by insertion.

According to FIG. 5, the insertion piece 2a with a throttle has a main body 21a that the step hole 22a crosses, and the step hole is separated by a conical connecting portion 223a and 225a, and a row of holes 222a having a diameter gradually decreasing. , 224a, 226a. The inlet 221a of the insert 2a has a conical shape that creates a seal seat, and the opening of the last hole 226a leading to the chamber 12a of the rail 1a has a rounded edge or a rounded 227a. The step hole 22a forms a throttle defined to weaken the pressure wave introduced into the high pressure liquid.

The outer surface 23a of the insertion piece 2a has a large-diameter conical portion 231a, and the small bottom portion of the conical portion corresponds to the small-diameter cylindrical portion 233a by the conical connecting portion 232a. The outer surface 23a ends with a roundness of 234a. The conical portion 231a has the same conical degree as the conical chamber 1312a of the connecting piece 13 and can be accommodated in the conical chamber 1312a by insertion so that the respective surfaces are in direct contact with each other. And have.

The cylindrical portion 233a has a cross section much smaller than the cross section of the hole 1314a of the connecting piece 13a.

According to the half-section view of FIG. 6, when the rail 1a includes all the insertion pieces 2a with a throttle, the auto-fletage as described for the first embodiment shown in FIGS. 1 to 3 is a rail. Is given to.

To that end, each connecting piece 13a has a closed body (not shown) with respect to the conical seat 221a of the insert 2a in order to create a seal between the outer surfaces of the holes 22a and between the conical surfaces of the portions 1312a and 231a. Is attached.

For this reason, a tightening force F is applied to a ball (not shown) that is supported and creates the compression zone C. This force is transmitted to the conical contact zone between the conical portion 231a of the insert 2a and the conical surface of the chamber 1312a of the connecting piece 13a.

This limits the surface of the hole 131a and of the insert piece 2a that will be exposed to the high pressure autofledgement of the liquid introduced into the rail.

The surface exposed in this way is an insertion piece including the inner surface and the outer surface of the insertion piece 2a, which is placed in front of the contact portion between the conical surface 231a and the surface of the conical chamber 1312a (in the outflow direction of the high-pressure fuel). The surface of the chamber 12a placed in front of the 2a and the surface of the passage 131a of the connecting piece 13a. The cross section of the small bottom of the conical portion 231a is larger than the cross section of the small bottom of the conical chamber 1312a corresponding to the conical surface 1313a. The conical surface forms the shoulder, in which case the insertion in combination with the autofletage allows the insertion piece 2a to be tightened tightly without contact with the shoulder 1313a which would interfere with or limit the insertion. ing.

It can be confirmed that the conical surface of the portion 1312a or 231a may have a groove that enhances the airtightness in the autofretage and enhances the residual axial force between the two portions / surfaces.

The surface of contact between the insert 2a and the hole 1312a receives the generated force rather than being exposed to the high pressure liquid of the autofretage. A very high autofledge pressure plasticizes the inner layer of the exposed surface of the rail 1a and the insert 2a, which is deformed and pressed against the hole 1312a of the connecting piece 13a. After this very high autofledge pressure is applied, the connecting pieces 13a shrink towards each insertion piece 2a, which causes the connecting pieces to shrink.

The forged steels of rails 1 and 1a have a minimum hardness on the order of 300 HB, which depends on the hardness of the conduit tip and properties that can be consistent with the expected results of autofretage.

The material of the inserts 2 and 2a exhibits sufficient plasticization during autofrette and at the same time retains sufficient residual elasticity to have sufficient residual pressure between the inserts 2 and 2a and the rails 1 and 1a. It has a hardness of 300-450 HV to continue.

The method for manufacturing the rails 1 and 1a according to the present invention is
The insertion pieces 2 and 2a are housed in the connection pieces 13 and 13a with a play and without the need to apply a large force.
Tightening the assembly thus created, thereby having a differential pressure between the inner and outer diameters of inserts 2 and 2a.
The purpose is to generate plastic deformations of the insert pieces 2, 2a and the rails 1, 1a.

The plastic deformation guarantees residual contact between the throttled inserts 2 and 2a and the rails 1 and 1a.

The material properties of the throttled inserts are selected to ensure sufficient residual force to hold the inserts 2, 2a in place during operation of the high pressure accumulators 1, 1a of the injection system.

1 Rail 11 Main body 12 High pressure chamber 13 Connection piece 131 Passage 1311 Entrance cone 1312 Cylindrical chamber 1312a Conical chamber 1313 Seal edge 1314 Hole 132 Male screw 2 Insert with throttle 21 Cylindrical body 21a Conical body 22 Step hole 221 Inlet cone 222 Large-diameter hole 223 Conical connection 224 Medium-diameter hole 225 Conical connection 226 Small-diameter hole 227 Roundness 23 Outer surface 231 Large-diameter cylindrical part 231a Large-diameter conical part 232 Conical connection part 233 Small-diameter cylindrical part 234 Roundness

Claims (11)

It is formed of a cylindrical body (11) defining a high-pressure chamber (12, 12a) and a connecting piece (13, 13a) having an outlet passage (131, 131a) leading to the high-pressure chamber (12, 12a). A method for manufacturing a high-pressure accumulator for a high-pressure injection system.
In order to weaken the pressure wave generated by the injectors placed on the downstream side of the connecting piece (13, 13a), is arranged a throttle (22, 22a) is at least one outlet passage (131,131a),
Said outlet passage (131,131a) includes a Chi Yanba (1312,1312a), said chamber (1312,1312a) houses the insert (2, 2a), wherein comprises a throttle (22, 22a),
A method for manufacturing a high-pressure accumulator, wherein the insertion pieces (2, 2a) are arranged in a force-coupling manner in the chambers (1312, 1312a) by an auto-frettage step of the high-pressure accumulator. The first aspect of the present invention, wherein the throttle (22, 22a) of the insertion piece (2, 2a) has a roundness (227, 227a) in the opening on the side of the high pressure chamber (12, 12a). Manufacturing method . A row of holes (222, 222a, 224, 224a, 226 ) having a diameter in which the throttle (22, 22a ) in the insertion piece (2, 2a) gradually decreases toward the high pressure chamber (12, 12a). , 226a) The manufacturing method according to claim 1, wherein the holes (22, 22a) are formed from the holes (22, 22a). The manufacturing method according to claim 1, wherein the throttle (22, 22a ) includes a conical inlet (221, 221a) forming a seal seat. The manufacturing method according to claim 1, wherein the connecting piece (13, 13a) has a conical inlet (1311, 1311a). The chamber (1312) is cylindrical and a shoulder portion (1313) forming a sealing edge is formed together with a hole (1314) leading to the high pressure chamber (12, 12a).
In order to allow the insertion piece (2) to enter the chamber (1312) with play during assembly, in the large diameter cylindrical portion and in the hole (1314) of the connection piece (13). It comprises an outer surface (23) with a freely protruding small diameter portion (233).
That the two parts (231, 233) of the insert (2) are connected by a conical segment (232) defined to hit the shoulder (1313) of the connection piece (13). The manufacturing method according to claim 1, which is characterized. Said connecting piece (13a), having said chamber conical (1312a), the該Chi Yanba,該Chi Yanba pores having a cross section smaller than the cross section of the small base of (1312a) (1314a) followed ,
Before Ki挿Irihen (2a) is, before a chitin Yanba (1312a) cone length shorter than the length of the a (231a), the cross section of the small base of the cone, said chamber (1312a) Larger than the cross section of the small bottom,
The manufacturing method according to claim 1, wherein the conical degree of the chamber (1312a) and the conical degree of the conical body (231a) are the same. The combination with cone (231a) which makes it possible to ensure the contact pressure, in order to enhance the sealing property during autofrettage, the surface and / or the cone before the winding Yanba (1312a) (231a) 7. The production method according to claim 7, wherein the surface of the surface has non-uniformity, unevenness, and a raised or recessed geometric shape. The cross section of the small diameter portion (233, 233a) of the insertion piece (2, 2a) entering the hole (1314, 1314a) leading to the high pressure chamber (12, 12a) is the high pressure accumulator (1, 1a). If in order to avoid contact with the hole after the autofrettage process before Symbol insert (2, 2a), and is smaller than the cross section of the hole, the manufacturing method according to claim 6. The length of the small-diameter portion of said insert piece (2,2a) (233,233a) is, the throttle (226,226a) of the open mouth leading to the front Symbol pressure chamber (12, 12a) holes (1314,1314A as the opening or it is away in), characterized in that it is shorter than the length of the hole (1314,1314A), the method according to claim 6. In the manufacturing method according to any one of claims 1 to 10.
By milling, chambers (1312, 1312a) are created in the outlet passages (131, 131a) of each connection piece (13, 13a).
Inserts (2, 2a) across which the throttles (22, 22a) cross are created, and the outer diameter of the insert is adapted to the inner diameter of the chamber (1312, 1312a).
The insertion pieces (2, 2a) are installed in each chamber,
The airtightness of the insertion piece (2, 2a) and the airtightness of the inlet of the connection piece (13, 13a) are ensured .
The high-pressure accumulator (1, 1a) assembled in this manner processes the inner surface of the high-pressure accumulator and inserts the insert (2) into the chamber (1312, 1312a) of the connection piece (13, 13a). A manufacturing method, characterized in that it is exposed to an autofretage pressure in order to dispose of 2a) in a force-coupling manner.

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