DE102008040639A1 - Pressure-balanced control valve for internal combustion engine, has high pressure chamber loaded with fuel through hole under system pressure, and another high pressure chamber formed in region between valve piece and valve element - Google Patents

Abstract

The valve (10) has a valve element (12) for opening or closing a valve seat (28) and cooperating with a valve piece (22) of the valve. The valve piece decompresses or pressurizes a high pressure chamber (26) under system pressure. The high pressure chamber is loaded with fuel through a hole (24) under system pressure. Another high pressure chamber (52) is formed in a region between the valve piece and the valve element. The high pressure chambers are in flow connection, and are pressurized when the valve element with the valve seat lies at a seat surface (30) of the valve piece.

Description

State of the art

DE 10 2005 039 911 A1 refers to an arrangement with a piezoelectric actuator. In an inner space of the piezoelectric actuator, a piezoelectric element is arranged, which acts on a nozzle needle when actuated by a mechanical arrangement located here below, with a coupler. As a result, the release of a nozzle opening takes place. Fuel contained in the interior of the fuel injector can thus be injected into the combustion chamber of an internal combustion engine. In this embodiment, a nozzle module, in which a needle-shaped injection valve is guided, a throttle plate and a spacer tube, in which the piezoelectric actuator is accommodated, screwed by means of a nozzle lock nut against each other and biased seen in the axial direction.

DE 100 31 265 A1 refers to a fuel injection valve having a valve body in which a bore is formed. The bore is delimited at its combustion-chamber-side end by a valve seat, from which at least one injection opening terminates, which opens into the combustion chamber of the internal combustion engine in the installation position of the fuel injection valve. In the bore is a piston-shaped valve needle, which is longitudinally displaceable. This has at its combustion chamber side, ie the valve seat facing the end of a valve sealing surface with which the valve needle cooperates with the valve seat. Here, in the closing direction of the valve needle, this means when the valve needle rests with its valve sealing surface on the valve seat, at least one injection port closed. When lifted from the valve seat valve needle fuel flows between the valve sealing surface and the valve seat, the injection openings and is injected from there into the combustion chamber of the internal combustion engine.

DE 10 2007 009 168 refers to a sealing seat. The sealing seat is formed in a switching valve, which comprises a valve seat and is opened or closed by a valve element. The valve element cooperates with a valve piece of the switching valve, which depressurizes or pressurizes a high pressure chamber under system pressure, to which the valve seat is assigned. At the valve seat extends between the valve member and the valve member limited by a Sitzabsetzkante seat boundary surface, which is carried out either on the valve element or on the valve piece.

at pressure compensated switching valves is the pressurized Medium, such as fuel, in the closed state of the Switching valve usually enclosed in a pressure chamber. The pressure chamber is on one side through your guidance and bounded on another side by a sealing seat. The Guide and the sealing seat have exactly the same diameter on. This creates no in the opening or closing direction acting force on the valve element. As the operation progresses of the switching valve, it comes to a match between the sealing surface the valve piece and the relative to this movable sealing surface on the valve element. This adjustment runs from the diameter starting only to one side, so this is a change the effective seat diameter and thus the generation of an opening direction has acting force on the valve element result. This is originally designed pressure-balanced switching valve disturbed in terms of pressure equalization. Associated with it goes through a change in his dynamic behavior for static leakage.

Disclosure of the invention

According to the invention proposed, in switching valves, which acts at a high pressure are, the wear occurring there to keep constant exploit the switching behavior of the switching valve. So far in the case of switching valves, a seating match is made over their service life, in which on the one hand an enlargement of the Anchor hubs sets and on the other hand creates a pressure stage. The resulting pressure level leads over the life the switching valve seen to the emergence of an opening direction the switching valve acting, additional force. It results itself, that as a result of a longer opening duration and an increased armature stroke increase in volume and on the other due to the increased opening force an earlier opening sets, which is also too a longer opening period leads.

Of the following solution according to the invention proposed, the wear mechanisms occurring so exploit that they work against each other. This can ideally the function of such a switching valve are kept constant, a Impairment of the valve behavior is reduced or at least be compensated, in particular over the life of a seen such switching valve.

Instead of a previously formed on the switching valve positive seat angle difference between a stationary valve member and a valve member movable relative to this, which is for example sleeve-shaped, a negative seat angle difference is performed. As a result, the sealing seat is no longer located at an inner edge of the sleeve-shaped valve element at a diameter d, but at one Outer edge of the seat boundary of the stationary valve piece at a diameter d + 2x. The operating principle can also be realized vice versa, so on a stationary, sleeve-shaped valve piece and on a relative to this movable, bolt-shaped valve element. This is already in the new state of the inventively proposed switching valve, a defined pressure level available. The sealing diameter is given by the diameter d + 2x, whereby the additional force acting in the opening direction is defined. This additional, acting in the opening direction of the switching valve force is smaller than that counteracting, applied via the closing spring valve spring force F _S , to ensure the sealing function. Seen over the life of the switching valve increases the armature stroke, the pressure level with sealing diameter d + 2x, however, is smaller due to the adjusting over the life of the switching valve seat alignment. Due to this circumstance, a lower resulting total opening force counteracts an increasing armature stroke. A lower resulting total opening force leads to a later opening and thus a shorter opening duration during which the switching valve proposed according to the invention is open. An enlarged armature stroke, however, causes a prolonged opening duration. Thus, the lower achieved, resulting total opening force, which, as stated above, leads to a shorter opening duration, caused by the increased armature stroke, counteracts extended opening duration.

With constant opening behavior due to each other opposite, outlined above effects of low resulting Total opening force and the enlarged Anchor stroke remains the injection behavior of a fuel injector, the with the inventively proposed switching valve equipped, constant. The seat angle, the negative seat angle difference, the seat diameter, the seat limit, material, hardness and coating etc. of the components are designed so that the functional influences as a result of over the life of the inventively proposed Reduce or compensate for switching valve.

From DE 10 2007 009 168 A1 originally existing seat limit on the valve piece is absolutely necessary in the proposed solution according to the invention to define the initial size of the defined pressure level in the new state exactly (sealing diameter = diameter d + 2x). Due to the seat limitation, the static tightness of the switching valve is guaranteed over its lifetime in any case. Furthermore, the initially occurring and acting in the opening direction compressive force can not increase, since the pressure level can not be larger - it is on the contrary smaller.

Brief description of the drawings

Based In the drawings, the invention will be described in more detail below.

It demonstrate:

1 a schematic representation of a pressure-balanced switching valve according to the prior art,

2 an inventively proposed, outside sealing, pressure compensated switching valve with seat limitation and negative seat angle difference when new,

3 a possible form of wear, which adjusts itself to the switching valve proposed according to the invention over its service life, whereby a wear occurs on the valve piece,

4 a possible self-adjusting wear on the switching valve seen over its lifetime, with the valve element adjusting wear,

5 a further embodiment of the inventively proposed, but internally sealing, pressure-balanced switching valve with seat limitation and negative seat angle difference in the new state and in a closed position, wherein the valve element is received as a solid body in the valve housing,

6 a partial section of the trained as a solid body valve element according to 5 in an open position in which the valve element is lifted with its valve seat from the seat surface of the valve housing.

The representation according to 1 is to take a pressure balanced trained switching valve according to the prior art.

An in 1 illustrated switching valve 10 comprises in addition to an outer sleeve-shaped valve element 12 a valve piece 22 , The switching valve 10 is symmetrical to its symmetry line 11 constructed, but can also be designed asymmetrically, with an offset between the injection valve member and the valve member. The sleeve-shaped valve element 12 is with an inner circumferential surface 18 at a guided tour 16 of the valve piece 22 guided. Between the inner circumferential surface 18 of the valve element 12 and the outer peripheral surface of the valve piece 22 there is a gap 20 who has a narrowly tolerated leadership 16 of the valve element 12 represents. As shown in 1 is the valve ment 12 in a valve seat 28 posed. As a result, the outflow of fuel under system pressure from a high-pressure chamber 26 over the valve seat 28 avoided. The high pressure room 26 , formed by an annular, pocket-shaped recess between the inner circumferential surface 18 of the valve element 12 and the valve piece 22 , will have at least one hole 24 filled with fuel at system pressure. With the valve seat closed 28 the fuel under system pressure is in the high-pressure chamber 26 at. In the area of the valve seat 28 has the valve element 12 a seat diameter 32 on. The sleeve-shaped valve element 12 sits in the presentation according to 1 on a seat 30 of the valve piece 22 and forms a contact line 34 , This is during the relative movement of the sleeve-shaped valve element 12 relative to the stationary valve piece 22 in the fuel injector of the switching valve 10 exposed to very high mechanical stresses.

Embodiments:

The representation according to 2 is an embodiment of the inventively proposed outside sealing, pressure balanced valve with seat limitation and negative seat angle difference in new condition to remove.

Out 2 such as 5 and 6 it turns out that the switching valve 10 the sleeve-shaped valve element 12 which is symmetrical to the symmetry line 11 is trained.

At the inner lateral surface 18 of the sleeve-shaped valve element, for example 12 is the seat diameter 32 , A sealing surface 40 of the sleeve-shaped valve element, for example 12 has the seat 30 the stationary formed valve piece 22 to. Between the sealing surface 40 and the seat 30 runs a wedge-shaped pressure chamber 52 in a new condition 50 the switching valve 10 - as in 2 shown - has a wedge-shaped appearance, for example, and in the radial direction inwardly between said surfaces 30 . 40 , starting from the contact line 34 , extends. The pressure room 52 can also - as an alternative to its wedge-shaped configuration - have rounded contours. The contact line 34 as shown in 2 works in new condition 50 the switching valve 10 with a sealing diameter 48 together. In mint condition 50 the seat 30 or the sealing surface 40 lies according to a seat limit 42 a pressure level 46 in front. The pressure level 46 can with the seat limit 42 coincide. Inside the wedge-shaped pressure chamber 52 between the seat 30 and the sealing surface 40 is the in the high pressure room 26 prevailing system pressure. System pressure is understood to mean a pressure level with which the pressure chamber 26 over the hole 24 in the stationary trained valve piece 22 is charged. In high-pressure accumulator systems, the system pressure is given by the pressure which is generated in the high-pressure accumulator space (common rail) of a high-pressure accumulator injection system in the high-pressure accumulator by a high-pressure demand unit, such as a high-pressure pump. As shown in the illustration 2 further, the sealing seat becomes 28 closed due to a closing force F _S , in the vertical direction on the sleeve-shaped valve element 12 is exercised. The closing force F _S is indicated by a in 2 not shown spring element generates which on the valve piece 22 guided valve element 12 acted upon in the vertical direction. By the in the high pressure room 26 over the hole 24 pending system pressure is in the wedge-shaped pressure chamber 52 in new condition 50 generates a closing force F _S counteracting, directed in the opening direction additional opening force. Due to the defined diameter 48 . 32 . 14 is one in new condition 50 in the opening direction on the sleeve-shaped valve element 12 acting opening force F well defined. Therefore, this can be taken into account in the design of the closing force F _S.

Like from the 2 . 5 . 6 continues to show, lies between the seat 30 at the valve piece 22 and the sealing surface 40 the sleeve-shaped valve element 12 a negative seat angle difference 44 in front. This causes the valve seat 28 no longer on the inner edge of the sleeve-shaped valve element 12 at the seat diameter 32 but at the outer edge of the seat boundary 42 the stationary recorded valve piece 22 at the sealing diameter 48 , As a result, the already mentioned defined pressure level 46 generates, which the additional, well-defined force F in the opening direction on the sleeve-shaped valve element 12 brings. This force F is smaller than that in the closing direction of the valve seat 28 the sleeve-shaped valve element 12 applied closing force F _S.

The originally existing seat limit 42 on the stationary mounted valve piece 22 is required to the initial size of the compression stage 46 in new condition 50 to define exactly. By the seat limit 42 is in any case the static tightness of the switching valve 10 as shown in 2 ensured over its lifetime. In addition, the initially occurring, acting in the opening direction compressive force F does not rise, since the pressure stage 46 , starting from new condition 50 , it can not become larger, it becomes, as in connection with the explanation of the 3 and 4 set out over the operating time of the switching valve 10 always smaller.

3 is a wear form of the valve or sealing seat over the life of the switching valve as shown in FIG 2 to remove, with set wear on the stationary valve piece.

As shown in the illustration 3 As can be seen, wear occurs as a possible form of wear on the stationarily arranged valve piece 22 on. At this adjusts itself to the seat 30 a match 54 one. Due to the adjustment 54 will be out of the 2 illustrated contact line 34 a contact surface 60 , Because of this circumstance is the new condition 50 according to 2 by reference numerals 52 indicated wedge-shaped pressure chamber to a second reduced wedge-shaped pressure chamber 56 , Due to the reduced volume of the second reduced wedge-shaped pressure chamber 56 , in which there is fuel under system pressure fuel acts on the sleeve-shaped valve element 12 only a reduced additional opening force F, since the pressure level 46 , in new condition according to 2 adjusts to a first reduced pressure level 58 is reduced. As a result, the opening force F acting in the opening direction, which counteracts the closing force F _S , decreases. Due to the occurring wear becomes the first reduced pressure stage 58 as a result of the adjustment 54 (see 4 ) steadily smaller. Due to the resulting wear due to the transition from the contact line 34 to the contact surface 60 is the additional force F generated in the opening direction, while the stroke (armature stroke), which the sleeve-shaped sealing element 12 in the vertical direction, gets bigger. As already mentioned, a lower resulting total opening force, which entails a later opening and a shorter opening time, counteracts an increased armature stroke and thus a longer opening duration.

That in the 5 and 6 only partially shown switching valve 10 differs from the switching valve 10 according to 1 to 4 in that the valve element 12 as a solid body or as a bolt-shaped valve element 12 is trained. The rest not further described at this point, but in the 5 and 6 shown, identified with reference numerals components of the switching valve 10 are in the description parts to the 1 to 4 explained in detail.

The switching valve 10 includes in addition to the outer sleeve-shaped valve piece 22 , The part of a valve body, not shown in the drawing of the switching valve 10 is the valve element 12 that in the illustrated embodiment as a solid body with an outer diameter 68 is trained. The valve element 12 consists essentially of a pressure element, not shown here, on which a likewise not shown rest spring is arranged, which is the valve element 12 in the direction of the valve seat 28 in the valve piece 22 pushes and thereby ensures a good seal.

The switching valve 10 is symmetrical to its symmetry line 70 constructed, but can also be designed asymmetrically, with an offset between the valve piece 22 and valve member. The sleeve-shaped valve element 12 is with the inner circumferential surface 18 at the lead 16 of the valve piece 22 guided. Between the inner circumferential surface 18 of the valve element 12 and an inner peripheral surface 21 of the valve piece 22 is the gap 20 who has the tightly tolerated leadership 16 of the valve element 12 represents. As shown in 5 is the valve element 12 in the valve seat 28 placed and is thereby in a valve opening closing position. As a result, the outflow of system under pressure fuel from the high-pressure chamber 26 over the valve seat 28 avoided.

The high pressure room 26 is through an annular, pocket-shaped recess between an outer circumferential surface 19 of the valve element 12 and the inner circumferential surface 21 of the valve piece 22 educated. The high pressure room 26 is via at least one high-pressure inlet, in particular via the bore 24 , filled with fuel at system pressure. With closed switching valve 10 the fuel under system pressure is in the high-pressure room 26 at. In the area of the valve seat 28 has the valve element 12 a seat diameter 72 on. The sleeve-shaped valve element 12 sits in the presentation according to 1 on the seat 30 of the valve piece 22 and thereby forms the contact line 34 , This is the case of the relative movement of the valve element designed as a solid body 12 relative to the stationary valve piece 22 in the fuel injector of the switching valve 10 exposed to very high mechanical stresses.

4 shows a possibly adjusting wear shape of the sleeve-shaped or bolt-shaped valve element 12 ,

While as shown in 3 a flattening of the seat 30 and the formation of a contact surface 60 takes place, digs according to 4 the sealing surface 30 of the stationary valve piece 22 in a recess 62 the sealing surface 40 the sleeve-shaped valve element 12 , In the illustration according to 4 the adjustment is greater, ie cm larger portion of the seat 30 of the valve piece 22 is in the recess 62 retracted. Due to the enlarged contact surface 60 , which are in the possible form of wear according to 4 can adjust is the wedge-shaped pressure chamber 52 in new condition 50 the switching valve 10 adjusted, again reduced and by a second additional reduced wedge-shaped pressure room 64 designated. Due to the renewed reduction of the wedge-shaped pressure chamber, as in 4 by reference numerals 64 compared to the embodiment according to FIG 3 implied, is also a second reduced pressure level 66 that attach to the remaining sealing surface 40 the sleeve-shaped valve element 12 training, again reduced. From the illustration according to 4 it shows that the contact line 34 that is in new condition between the sealing surface 40 and the seat 30 adjusts, is turned inward in the radial direction and the gusset of the second reduced wedge-shaped pressure chamber 64 identified. As 4 Further shows is due to the second reduced pressure level 66 the additional force F acting in the opening direction in comparison to the illustration according to FIG 2 that the new condition 50 the switching valve 10 indicates, again reduced. The transition of the seat 30 from a linear contact 34 in new condition 50 in a flat contact forming the contact surface 60 the seat 30 into the recess 62 the sealing surface 40 can also be composed as mixed wear form, ie from both phenomena at the same time, ie as a combination of the wear form according to 3 and 4 occur. Of importance in the occurring wear form the fact that starting from the well-defined pressure stage 46 ( 2 . 5 . 6 ) in new condition 50 in training the contact line 34 at the sealing diameter 48 a successive reduction of the pressure levels 58 . 66 takes place, so that in opposite to an extension of the anchor stroke is achieved. A steadily decreasing resulting total opening force, which results in a later opening and a shorter opening duration, runs at the same time continuously ver increasing anchor stroke, the longer opening duration of the valve seat 28 causes, so that seen in sum, the two mechanisms compensate each other and the function of the switching valve 10 Ideally, it can be kept constant.

In the 3 shown wear shape then turns when, for example, the hardness of the material of the valve piece 22 smaller than the hardness or the coating with which the sealing surface 40 the sleeve-shaped valve element 12 is coated. The wear shape according to 4 can, for example, then adjust when the hardness or the material of the stationary valve member 22 on the seat 30 greater than the hardness of this opposite sealing surface 40 of the sleeve-shaped valve element 12 the switching valve 10 , The seat angle difference, in particular the negative seat angle difference 44 , the seat diameter 32 , the seat limit 42 as well as material, hardness and coatings are designed so that the functional influences of the switching valve 10 be reduced due to the mechanical wear occurring or, as stated above, compensate each other.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102005039911 A1 [0001]
• DE 10031265 A1 [0002]
• - DE 102007009168 [0003]
• DE 102007009168 A1 [0009]

Claims (13)

Switching valve ( 10 ) with a valve seat ( 28 ) opening or closing valve element ( 12 ), which with a valve piece ( 22 ) of the switching valve ( 10 ), which is a high-pressure space under system pressure ( 26 ) is depressurized or pressurized through a bore ( 24 ) is acted upon by fuel under system pressure, characterized in that at least in the region between the valve piece ( 22 ) and the valve element ( 12 ) another high pressure room ( 52 ) is formed. Switching valve ( 10 ) according to claim 1, characterized in that between the valve seat ( 28 ) of the valve element ( 12 ) and the valve piece ( 22 ) of the switching valve ( 10 ) the further high-pressure space ( 52 ) is formed. Switching valve ( 10 ) according to claim 1, characterized in that the two high pressure spaces ( 26 . 52 ) are in flow communication and are pressurized, in particular when the valve element ( 12 ) with its valve seat ( 28 ) on a seat surface ( 30 ) of the valve piece ( 22 ) of the switching valve ( 10 ) is present. Switching valve ( 10 ) according to claim 1, characterized in that between the valve piece ( 22 ) and the valve element ( 12 ) a negative seat angle difference ( 44 ) is executed and the valve seat ( 28 ) with respect to a seat diameter ( 32 ) on an enlarged sealing diameter ( 48 ) lies. Switching valve ( 10 ) according to claim 1, characterized in that in a new state ( 50 ) of the switching valve ( 10 ) on the valve seat ( 28 ) a contact line ( 34 ) between the seat ( 30 ) and a sealing surface ( 40 ) is trained. Switching valve ( 10 ) according to claim 1, characterized in that when new ( 50 ) of the switching valve ( 10 ) the pressure chamber ( 52 ) through the contact line ( 34 ), the sealing surface ( 40 ) and the seat ( 30 ) is limited. Switching valve ( 10 ) according to claim 1, characterized in that the valve element ( 12 ) is sleeve-shaped or formed as a solid body and the valve piece ( 22 ) of the sleeve-shaped valve element ( 12 ) is surrounded or the valve piece ( 22 ) the Vollkör by the valve element ( 12 ), while in new condition ( 50 ) of the switching valve ( 10 ) a pressure stage ( 46 ) by a seat limitation ( 42 ) on the valve piece ( 22 ) and at least part of the sealing surface ( 40 ) of the valve element ( 12 ) is formed, wherein the valve element against the action of a closing force (F _S ) is acted upon in the opening direction. Switching valve ( 10 ) according to one or more of the preceding claims, characterized in that an additional opening force (F) acting in the opening direction is smaller than that of the sleeve-shaped valve element ( 12 ) acting in the closing direction closing force (F _S ). Switching valve ( 10 ) according to claim 1, characterized in that the valve seat ( 28 ) on the outer edge of the seat limit ( 42 ) lies. Switching valve ( 10 ) according to one or more of the preceding claims, characterized in that the switching valve ( 10 ) in the region of the valve seat ( 28 ) after a period of operation a reduced pressure space ( 56 ), which in the closed position of the switching valve ( 10 ) with the first pressure chamber ( 26 ) is in flow connection and at the switching valve ( 10 ) by matching ( 54 ) bounded by a contact surface ( 60 ) between the valve element ( 12 ) and the adjoining valve piece ( 22 ) is formed. Switching valve ( 10 ) according to claim 1, characterized in that over the life of the switching valve ( 10 ) acting in the opening direction, at the pressure stage ( 46 ) engaging force (F) decreases continuously and a stroke of the sleeve-shaped valve element ( 12 ) along a guide ( 16 ) increases continuously. Switching valve ( 10 ) according to one or more of the preceding claims, characterized in that the switching valve ( 10 ) is received in a fuel injector and the high-pressure space under system pressure ( 26 ) depressurized. Switching valve ( 10 ) according to one or more of the preceding claims, characterized in that the high-pressure space acted upon by fuel under system pressure ( 26 ) with the second pressure chamber ( 56 . 64 ) connected is.