WO2005045230A1

WO2005045230A1 - Pressure control valve comprising a backflow restrictor

Info

Publication number: WO2005045230A1
Application number: PCT/EP2004/012148
Authority: WO
Inventors: Günter Kampichler; Herbert Geier
Original assignee: Motorenfabrik Hatz Gmbh & Co. Kg
Priority date: 2003-11-05
Filing date: 2004-10-27
Publication date: 2005-05-19
Also published as: BRPI0416271A; CN1867764A; JP2007510098A; DE20317003U1; EP1680594A1

Abstract

The invention relates to a pressure control valve (1) comprising a backflow restrictor for installation in a transport line (9) between a pump working chamber (21) of a fuel-injection pump and an injection nozzle (10) of a compression-ignition internal combustion engine. Said valve comprises: a valve housing (2) in the form of a port with a graduated axial through-bore (3); an insert, positioned on the side of the pump working chamber and containing an axial passage (12; 12, 33, 34, 35, 36), the end of said insert on the nozzle side having a first valve seat (13) that surrounds the axial passage; a valve plate comprising a cavity (15), which forms an elastically deformable, tongue-shaped constriction (16) with a first valve closing member that can be raised from its seal seat by means of a fuel pressure on the side of the pump working chamber, causing an elastic deformation of the tongue-shaped constriction; and a restrictor bore that is configured in the first valve closing member (17).

Description

Pressure valve with backflow throttle

According to its type, the present invention relates to a pressure valve with a backflow throttle for installation in a delivery line between a pump work chamber of a fuel injection pump and an injection nozzle of a self-igniting internal combustion engine.

In the case of a pressure valve which is to be assumed to be known and which is arranged in the pressure line between a pump work space and an injection point, the delivery pressure of the fuel lifts a valve closing member from its valve seat, as a result of which the pressure valve opens against the spring force of a valve spring and fuel can flow to the injection point. At the end of high-pressure delivery, the valve closing member returns to its sealing seat; at the same time the injection point closes.

It is essential here that the pressure at the injection nozzles builds up quickly and as soon as possible. However, this presupposes that the volume to be filled with fuel is as small as possible in order to keep the time delay caused by its filling as small as possible. However, construction-related cavities, so-called harmful spaces, can hardly be avoided.

Furthermore, the sudden end of high-pressure delivery in the enclosed volume between the pressure valve and the injection point can result in pressure waves which run back and forth between the pressure valve and the injection point. Such pressure waves are optionally able to open the closed injection nozzles of the injection point again in an undesirable manner. so that fuel can drip there and possibly form undesirable combustion residues.

In order to avoid pressure waves, it is known to provide a backflow throttle which is permeable against the passage direction of the pressure valve and by means of which the pressure in the pressure line can decrease after the pressure valve closes to a specific, predefinable stand pressure.

In a conventional manner, such a backflow throttle is arranged in a separate recess in the through bore of the valve housing of the pressure valve. The return flow throttle generally consists of a cartridge case arranged in the recess with a valve seat formed on the ring end face on the nozzle side thereof, and a valve plate lying on the nozzle end face of the cartridge case, which has a sealing surface interacting with the valve seat and is provided with a throttle bore opening into the lumen of the cartridge case and a return flow throttle spring pressing the valve plate onto its sealing seat. In the function of the fuel delivered, the valve plate is lifted from its sealing seat against the force of the return flow throttle spring and moved in the direction of the injection point until it strikes a corresponding stop surface in order to unhinderedly open the flow path for the fuel. After the end of the delivery, the valve plate is pressed back onto its sealing seat by the spring force of the return flow throttle spring and the pressure in the delivery line is reduced via the throttle bore to a stand pressure specified by the spring force of the return flow throttle spring.

A disadvantage of the known backflow throttle is that enough space is available for the arrangement of the backflow throttle spring. must be provided, which in the above-mentioned sense is to be regarded as harmful space for rapid fuel transport to the injection point. In addition, a conventional backflow throttle is very susceptible to wear, since the valve plate strikes its abutment surface violently when the pump piston is suddenly opened and generates abrasion. Furthermore, a conventional backflow restrictor can only be dismantled with great effort.

The object of the present invention is to avoid the disadvantages mentioned of the conventional pressure valves with a backflow throttle and consequently to provide a pressure valve with a backflow throttle with a reduced clearance, less susceptibility to wear and easier dismantling.

This object is achieved according to the invention by a pressure valve with a backflow throttle according to claim 1 of the invention. Advantageous embodiments of the invention are specified by the features of the subclaims.

The pressure valve according to the invention with a backflow throttle comprises a valve housing in the form of a pipe socket with a step-shaped axial through-bore, which widens in the direction of the pump work space into a first hollow cylindrical recess and adjoins a second hollow cylindrical recess, the second hollow cylindrical recess having a larger cross-sectional diameter has as the first hollow cylindrical recess. ^• The through hole accordingly widens in the direction of the pump work space first into a first receptacle and immediately thereafter into a second receptacle, so that the through hole has three steps, one over the other. has sections. When the through hole is widened to the first recess, the nozzle-side cover surface of the first hollow cylindrical recess which is recessed by the opening of the through hole forms a step which forms an annular first stop surface. When the through-hole is widened from the first recess to the second recess, the nozzle-side cover surface of the second hollow cylindrical recess which is cut out through the opening of the first recess forms a step which forms an annular second stop surface.

The pressure valve according to the invention further comprises an insert device inserted into the second hollow cylindrical recess of the valve housing on the pump working space side. The insert device, which can be made in one or more parts, is provided with an axial through-channel. In addition, the nozzle-side end of the insert device has a first valve seat surrounding the axial through-channel.

Furthermore, the pressure valve according to the invention comprises a valve plate which is pressed through the nozzle-side end of the insert device against the annular second stop surface of the second recess. It is essential here that the valve plate is provided with an opening through which an elastically deformable tongue-like constriction is formed with a first valve closing member connected to the tongue-like constriction. In other words, the opening of the valve plate cuts out the contour of a tongue-like constriction with a first valve closing member connected to it, the tongue-like constriction remaining connected to the rest of the valve plate. The tongue-like constriction is dimensioned such that an elastic deformability of the tongue-like Constriction or the attached first valve closing member is guaranteed. In other words, by means of the elastic deformability of the tongue-like constriction, the first valve closing member can be pivoted out of the surface plane of the valve plate.

It is characteristic of the invention that the first valve closing member is dimensioned such that on the one hand it covers the mouth of the axial through channel of the insert device, and on the other hand there is space in the axial extension within the ring-shaped second stop surface, so that the first valve closing member has elastic deformability the tongue-like constriction pivotal movement can occur in the first receptacle. In addition, the first valve closing member is provided with a first sealing surface which interacts with the first valve seat of the insert device.

According to the invention, the first valve closing member can be lifted from its sealing seat by an elastic deformation of the tongue-like constriction causing fuel pressure on the pump chamber side, the first valve closing member entering the first recess of the valve housing during this pivoting movement about the tongue-like constriction. The first valve closing member is also dimensioned with respect to the axial height of the hollow cylindrical first recess in such a way that, when pivoted sufficiently, it comes to rest against the first stop surface of the first recess.

In order to act as a backflow throttle, the first valve closing element according to the invention has a throttle bore formed within the axial extension of the mouth of the axial through bore of the insert device. To one To achieve throttling effect, the diameter of the throttle bore is smaller than the diameter of the mouth of the axial through bore of the insert device.

In a first preferred embodiment of the pressure valve according to the invention, the insert device is designed in one piece in the form of a tubular valve body provided with an axial through-bore. The pressure valve therefore essentially consists only of a pressure connection between the valve housing and valve body with a backflow throttle pressed between them. In this embodiment, the backflow throttle fulfills not only a throttle function for reducing pressure waves in the delivery line, but also the actual function of the pressure valve, namely opening and closing of the delivery line depending on the fuel pressure on the pump work chamber side. Such a construction of the pressure valve with backflow throttle, which is greatly simplified compared to conventional pressure valves with a backflow throttle, is greatly reduced in damage space since, apart from the through bore of the valve body and the through bore of the valve housing, only an expansion of the through bore of the valve housing into a first recess and a second recess is to be provided ,

In a further preferred embodiment of the pressure valve according to the invention with a backflow throttle, the valve body with an axial through bore formed therein can have an annular surface forming a second valve seat. The pressure valve is then further equipped with a second valve closing member, which is axially displaceable in the axial through bore of the valve body against the spring force of a valve spring arranged in the second recess of the valve housing, and one with the second valve seat of the valve body cooperating second sealing surface.

In a further preferred embodiment of the pressure valve according to the invention with a backflow throttle, the insert device is constructed in several parts and comprises a tubular valve body provided with an axial through-bore, a cartridge sleeve with its ring end face on the pump working chamber side of the nozzle side ring end face of the valve body and a ring end face on the nozzle side of the nozzle end sleeve surface with its pump working chamber side inner sleeve. The valve body forms a second valve seat with its ring face on the nozzle side. The pressure valve further comprises a second valve closing member which is axially displaceably guided in the axial through bore of the valve body against the spring force of a valve spring arranged in a spring chamber of the second recess of the valve housing and has a second sealing surface which interacts with the second valve seat of the valve body.

The invention will now be explained in more detail with reference to the description of two exemplary embodiments of the present invention, reference being made to the accompanying drawings. Show it

1 shows an example of a preferred embodiment of the present invention with a one-piece insert device;

Fig. 2 shows an example of a preferred embodiment of the present invention with multi-part insert device. Fig. 1 shows an example of the pressure valve according to the invention with backflow throttle with a one-piece insert device. The pressure valve 1 comprises a valve housing 2 in the form of a pipe socket with a step-shaped axial through-bore 3. The through-bore 3 widens in the direction of the pump work space into a first hollow-cylindrical recess 4 and into a second hollow-cylindrical recess 5. The second hollow-cylindrical recess 5 has one Larger cross-sectional diameter than the first hollow cylindrical recess 4. The first hollow cylindrical recess 4 has an annular first stop surface 6 in the direction of the injection nozzle, while the second hollow cylindrical recess 5 has an annular second stop surface 7 in the direction of the injection nozzle. On the nozzle side, the through hole 3 opens into an opening cone 8 for connection to the delivery line 9 for supplying fuel to the injection point 10.

On the pump work chamber side, an insert device in the form of a one-piece valve body 11 is inserted into the second hollow cylindrical recess 5 of the valve housing 2. The valve body 11 is provided with an axial through channel 12. The end of the valve body 11 on the nozzle side has a first valve seat 13 surrounding the axial through-channel 12. The axial through channel 12 of the valve body 11 is arranged in the axial extension of the through hole 3 of the valve housing 2. Valve housing 2 and valve body 11 are screwed together in a conventional manner (not shown). The end of the valve body 11 on the pump work chamber side is fastened in a fluid-tight manner by means of a sealing element 20 to an element cylinder 22 of the pump element forming a pump work chamber 21. A valve plate 14 made of sheet steel is clamped between the nozzle-side end of the valve body 11 and the annular second stop surface 7 of the second recess 5 (see enlarged illustration of the valve plate 14 at the top right in FIG. 1). As can be seen from the enlarged illustration of the valve plate 14, the valve plate 14 is provided with an opening 15 in the form of a partial ring. By means of the opening 15, an elastically deformable tongue-like constriction 16 is formed with a first valve closing member 17 connected to the tongue-like constriction. The first valve closing member 17 is dimensioned such that on the one hand it covers the opening 18 of the axial through-channel 12 of the valve body 11, and on the other hand it is arranged in the axial extension within the annular second stop surface 7 of the second recess 5. In addition, the first valve closing member 17 is provided with a first sealing surface 18 which interacts with the first valve seat 13 of the sealing end face of the valve body 11. The first valve closing member 17 can be moved out of the surface plane of the valve plate 14 by pivoting about the elastically deformable tongue-like constriction 16.

The first valve closing member 17 can be lifted from its sealing seat 13 by an elastic deformation of the tongue-like constriction 16 causing fuel pressure on the pump chamber side by pivoting around the elastically deformable tongue-like constriction 16, the first valve closing member 17 entering the first recess 4 of the valve housing 2 and to Contact the first stop surface 6 of the first recess 4. Furthermore, the first valve closing member 14 has a throttle bore 19 within the axial extension of the opening 18 of the axial through bore 12 of the valve body 11. In order to achieve a throttling effect, the throttle bore 19 has a smaller diameter than the axial through bore 12 of the valve body 11. For example, the throttle bore has a diameter of 0.5-1.0 mm. 1, the through bore 3 of the valve housing 2, the through bore 12 of the valve body 11 and the throttle bore 19 of the first valve closing member 17 are axially aligned with one another.

The embodiment of the pressure valve according to the invention shown in FIG. 1 functions as follows: The fuel, which is delivered under high pressure and is pumped by the pump element, causes the first valve closing member 17 to be lifted from its sealing seat 13 against the elastic deformation force of the tongue-like constriction, whereby the first valve closing member 17 enters the first recess 4 of the valve housing 2 and finally comes to rest against the annular first stop surface 6 of the first recess 4. The fuel can now flow freely from the pump work chamber 21 of the element cylinder 22 of the pump element to the injection point 10. Because of the sudden end of delivery, the first valve closing member 17 is pressed by the “overpressure” in the delivery line with its sealing surface 18 onto the sealing seat 13 and closes the delivery line to the injection point. Any pressure waves between the first valve closing member 17 and the injection point 10 are reduced via the throttle bore 19 until a stand pressure is reached in the delivery line which is predetermined by the force required for the elastic deformation of the tongue-like constriction. Fig. 2 shows an example of the pressure valve according to the invention with backflow throttle with a multi-part insert device. The elements analogous to the embodiment of the pressure valve according to the invention from FIG. 1 have the same reference numbers. In order to avoid unnecessary repetitions, only the difference in the design of the pressure valve from FIG. 1 is explained with regard to the embodiment of the pressure valve shown in FIG. 2.

The insert device of the pressure valve 1 of FIG. 2 comprises a tubular valve body 11 provided with an axial through-bore 12, a cartridge sleeve 23 with its ring end face 24 on the pump work chamber side of the nozzle side ring end face 25 of the valve body 11, and a cartridge sleeve 23 with its ring end face 26 on the pump side of the nozzle end face 27 of the nozzle end face 27 Cartridge sleeve 23 abutting inner sleeve 28. The inner sleeve 28 is provided with a through hole 36. The valve body 11 forms a second valve seat 29 with its annular end face 25 on the nozzle side.

The pressure valve 1 further includes a second valve closure member 30, which is one of the valve housing 2 arranged in a spring chamber 35 of the second recess 5 valve spring guided in the axial through-bore 12 of the valve body 11 against the spring force ^'31 axially. The second valve closing member 30 also has a second sealing surface 32 which interacts with the second valve seat 29 of the valve body 11. In order to connect the second recess 5 to the through bore 12 of the valve body 11, a groove 33 is provided in the circumferential surface of the second valve closing member 30, which opens into an annular groove 34 arranged upstream of the second sealing surface 32. Valve housing 2 and valve body 11 are connected to one another in a conventional manner. screws (not shown), the cartridge case 23 and the inner sleeve 28, as well as the valve plate 14 being pressed against one another. The axial through-channel of the insert device of the embodiment shown in FIG. 2 is formed by the through-bore 12, groove 33, annular groove 34, spring chamber 35 and through-bore 36 of the inner sleeve 28.

The mode of operation of the embodiment of the pressure valve according to the invention shown in FIG. 2 is as follows: due to the fuel, which is pumped under high pressure, the second valve closing member 30 is lifted against its force against the force of the valve spring 31 from its sealing seat 29 and the pressure valve 1 is released from transferred its closed position into an open position in which the annular groove 34 opens into the spring chamber 35 of the valve spring 31. Due to the high fuel pressure, the first valve closing member 17 is also lifted from its sealing seat 13 against the force counteracting an elastic deformation of the tongue-like constriction 16, the first valve closing member 17 entering the first recess 4 of the valve housing 2 and finally abutting against the annular first stop surface 6 of the first recess 4 arrives. The fuel can now flow freely from the pump work chamber 21 of the element cylinder 22 of the pump element to the injection point 10. Due to the sudden end of delivery, the second valve closing member 30 is pressed onto its sealing seat 29 by the spring force of the valve spring 31 and the pressure valve is transferred from its open position to the closed position. At the same time, the first valve closing member 17 is pressed with its sealing surface 18 onto the sealing seat 13 by the “excess pressure” in the delivery line. Any pressure waves between valve closing member 17 and injection point 10 are reduced via the throttle bore 19 until a static pressure is established, which results from the the elastic deformation of the tongue-like constriction gives the necessary force.

Claims

Expectations

Pressure valve (1) with backflow throttle for installation in a delivery line (9) between a pump work chamber (21) of a fuel injection pump and an injection nozzle (10) of a self-igniting internal combustion engine, comprising a valve housing (2) in the form of a pipe socket with a step-shaped axial through hole (3) Which through bore (3) widens in the direction of the pump work space (21) into a first hollow cylindrical recess (4) and adjoins the first hollow cylindrical recess (4) into a second hollow cylindrical recess (5), the second hollow cylindrical recess (5 ) has a larger cross-sectional diameter than the first hollow cylindrical recess (4), the first hollow cylindrical recess (4) in the direction of the injection nozzle having an annular first stop surface (6) and the second hollow cylindrical recess (5) in the direction of the injection nozzle having an annular second Has stop surface (7), egg ne insert device on the pump workspace side into the second hollow cylindrical recess (5) of the valve housing (2) with an axial through channel (12; 12, 33, 34, 35, 36), the nozzle-side end of the insert device having a first valve seat (13) surrounding the axial passage, one by means of the nozzle-side end of the insert device against the annular second stop face (7) of the second recess (5) pressed valve plate (14), which valve plate with an opening (15) is provided, by means of which an elastically deformable, tongue-like constriction (16) is formed with a first valve closing member (17) connected to the tongue-like constriction, which first valve closing member (17) the mouth (18) of the axial through-channel (12; 12 , 33, 34, 35, 36) of the insert device and is arranged in the axial extension within the annular second stop surface (7), and is provided with a first sealing surface (18) cooperating with the first valve seat (13) of the insert device, wherein the first valve closing member (17) can be lifted off its sealing seat by an elastic deformation of the tongue-like constriction causing fuel pressure on the pump chamber side, whereby the first valve closing member (17) enters the first recess (4) of the valve housing (2) and abuts against the first Stop surface (6) of the first recess (4), one in the first valve closing member (17) within the axial extension of the opening (18) of the axial through channel (12; 12, 33, 34, 35, 36) of the insert device designed throttle bore (19), which has a small diameter, as the opening (18) of the axial through-channel (12; 12, 33, 34, 35, 36) of the insert device.

2. Pressure valve according to claim 1, characterized in that the valve plate (14) has a disk shape.

3. Pressure valve according to claim 1 or 2, characterized in that the opening (15) is designed in the form of a partial ring.

4. Pressure valve according to one of the preceding claims, characterized in that the valve plate (14) is made of sheet steel.

5. Pressure valve according to one of the preceding claims, characterized in that the throttle bore (19) has a diameter in the range of 0.5-1.0 mm.

6. Pressure valve according to one of claims 1 to 5, characterized in that the insert device is a tubular valve body (11) provided with an axial through-bore (12).

7. Pressure valve according to claim 6, wherein the valve body (11) has an annular surface forming a second valve seat, the pressure valve further comprising a second valve closing member, which in the axial through bore of the valve body against the spring force of a valve spring arranged in the second recess of the valve housing axially is displaceably guided and has a second sealing surface interacting with the second valve seat of the valve body.

8. Pressure valve according to one of claims 1 to 5, in which the insert device has a tubular valve body (11) provided with an axial through-bore (12), one with its pump working space side Ring end face (24) of the nozzle-side ring end face (25) of the valve body engages the cartridge sleeve (23) and an inner sleeve (28) adjoining the pump work chamber side ring end face (26) of the nozzle-side ring end face (27) of the cartridge case (23), the valve body (11) with its nozzle-side ring end face (25) forms a second valve seat (29), and wherein the pressure valve (1) further comprises a second valve closing member (30) which is in the axial through bore (12) of the valve body (11) against the spring force of a spring chamber (35) of the second recess (5) of the valve housing (2) arranged valve spring (31) is guided axially displaceably and has a second sealing surface (32) which interacts with the second valve seat (29) of the valve body (11).