DE102007012706A1 - Valve for fuel injectors - Google Patents

Abstract

Fuel injector (10) having a holding body (12), with a nozzle body (20), in which a by means of an actuating member (26), in particular by means of a solenoid valve, actuated, preferably needle-shaped, injection valve member (24) is received, with an armature assembly ( 44) which can be actuated via the actuating member (26), in particular a solenoid valve, which controls the pressure relief or pressurization of a control chamber (64), characterized in that in the armature assembly (44) a with at least one seat (50, 82) cooperating valve element (48) is integrated.

Description

State of the art

DE 196 50 865 A1 describes a solenoid valve for controlling the fuel pressure in a control chamber of an injection valve, such as a common rail injection system. About the fuel pressure in the control chamber, a stroke movement of a valve piston is controlled with an injection port of the injection valve is opened or closed. The solenoid valve comprises an electromagnet, a movable armature and a valve member which is moved with the armature and acted upon by a valve closing spring in the closing direction and which cooperates with the valve seat of the solenoid valve and thus controls the fuel drain from the control chamber.

In known solenoid valves, the swing occurring during operation of the armature and / or bouncing of the valve member has a disadvantageous effect. By a ringing of the impinging on the valve seat anchor plate this assumes an undefined position. Thus, in the case of subsequent injection processes with the same activation, different opening times of the solenoid valve occur, and thus a scattering of the time of commencement of injection and the quantity of fuel injected at this time. According to DE 196 50 865 A1 and DE 197 08 104 A1 the armature of the solenoid valve is designed as a two-part armature, so as to reduce the moving mass of the unit armature / valve member and thus the bouncing kinetic energy. The two-part formed anchor comprises an anchor bolt and an armature plate slidably received on the anchor bolt against the force of a return spring in the closing direction of the valve member under the action of its inertial mass, which is secured to the anchor bolt by means of a lock washer and a securing sleeve surrounding it. The locking sleeve and the locking washer are enclosed by the magnetic core, resulting in an increased space requirement and resulting in a higher diameter in the magnetic core. Due to the higher diameter in the magnetic core in turn results in a limitation of the magnetic flux.

The Previously used types of fuel injectors are relative elaborately made. There must be a valve seat in the valve piece in conical shape, a long guide surface along the anchor bolt, a guide surface in the anchor guide and a guide surface in the anchor plate by means of the machining process, usually of grinding, are produced. additionally is the quality of the guide of the anchor plate through an indirect guidance over the anchor bolt relative low. The power transmission from the anchor plate on the Anchor bolt takes place via a sickle disk. By the asymmetrical taking place power transmission leads to tilting and to wear at the contact point. The production the height-ground sickle-disk remains extreme elaborate and the side taking place very much complicated.

at current series products, the problem arises that the one Closing force on the anchor bolt performing valve spring Transverse force components in the assembly of anchor plate and anchor bolt initiates. Due to the guiding play between the anchor guide and the anchor bolt, this leads to a tilt of the Anchor bolt in the anchor guide. With strong lateral force This tilting can also be in the upper position of the anchor bolt be present at energized electromagnet. This will become a part the previously carefully set anchor stroke, d. H. the Movement of the anchor bolt in operation not complete exploited. This in turn leads to a lower injection quantity of fuel into the combustion chamber of an internal combustion engine. In addition, the friction of the anchor bolt in the anchor guide, which also affects the movement of the anchor bolt. This friction increases with greater tilt angle, since the lever arm the triggering force is also increasing. The point of attack of Valve spring has a relatively large distance to the upper End of the anchor guide. This results in the upper and at the lower end of the anchor guide very high punctual acting Forces on the anchor bolts, which adds friction strengthen and thus slow down the movement of the anchor bolt. However, the speed at which the anchor bolt moves, d. H. the opening and closing of the valve element, has a huge impact on the combustion chamber the internal combustion engine respectively introduced amount of fuel.

The known from the prior art valves associated with used with solenoid operated fuel injectors are relatively expensive in their manufacture due to the large number of Assembly and manufacturing processes to the required surface finish to reach.

Disclosure of the invention

Following the solution proposed according to the invention, an armature assembly is proposed for a fuel injector actuated by means of a solenoid valve, in which a single or double-switching valve element is integrated. In an advantageous embodiment of the invention underlying idea, the valve element is designed spherical. Instead of the spherical shape, other design possibilities of the valve element are also conceivable, for example as a slide which covers one or more slide seat edges in the valve body or releases according to its switching position.

Prefers becomes the anchor assembly proposed according to the invention manufactured as a "built valve", whereby on the one hand the spherical trained valve body in the way of a cohesive Joining method, such as welding, a Anchor plate of the armature assembly can be welded and on the other hand on the ball-shaped valve element a guide body which is substantially cylindrical is formed to be attached by means of welding can. In a first embodiment of the invention underlying idea is a very compact anchor assembly included, in addition to the anchor plate, which has a closing spring acted upon is already the valve element in spherical form, about which a in the valve body of the switching valve of the solenoid valve actuated fuel injector trained seat released or can be closed.

In a further embodiment of the invention is based lying thought, will also be a "built valve" discloses which has an armature assembly, in addition to the also in this embodiment spherically formed Valve element on the one hand an anchor bolt and on the other hand a Has guide body. At the anchor bolt is the Anchor plate of the armature assembly via a lock washer attached, which forms a stop, which in turn by a Locking sleeve is overlapped. The locking sleeve, which covers the lock washer on the anchor bolt of the armature assembly, has to a spring-trained stop. The springy trained stop is in a through hole of the Magnetic core of the solenoid valve assembly added, in turn in a cavity of the holding body of the fuel injector is included.

Both Embodiments of the invention are based The common idea is that the armature assembly proposed by the invention, by means of a solenoid valve operable fuel injector from several components in the way of a cohesive Joining process, such as welding or soldering is made of individual components. The anchor assembly either comprises a valve element which is simply switching is, or a valve element which is double-switching and a first and a second seat within the valve body releases or closes and also in an intermediate position can be held between the first and the second seat.

in the Contrary to today used anchor assemblies - are she is one or more parts trained - can be by the solution proposed by the invention save a wealth of operations, in particular when the valve element is spherical can. If the valve element is spherical, then already existing standard parts can be used, so that the manufacturing costs of the invention proposed Armature assembly can be significantly reduced and In addition, a very kompaktbauendes about a solenoid valve to actuating switching valve is obtained.

About that In addition, in the embodiment of the present invention proposed Anchor assembly integrating a spherically shaped Valve element with double switching function an intermediate position of Valve element achieved between a first and a second seat become. As a result, smaller pre-injection quantities can be achieved on the one hand realize and on the other hand a quick switching of the valve element cause the injected during the main injection phase Fuel quantity in the middle position of the double-switching Valve trained valve element can be achieved.

The According to the invention proposed switching valve for Actuation by means of a magnet builds very compact and provides a fast-switching, force-balanced solution which can be used in particular "inline".

Brief description of the drawings

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

It shows:

1 a first embodiment of the proposed invention designed as a built-valve armature assembly for a operated with a solenoid valve fuel injector and

2 a second embodiment proposed according to the invention for an armature assembly, designed as a built-valve, for actuating a operated with a solenoid fuel injector.

embodiments

The representation according to 1 is a first embodiment of the inventively proposed designed as a built valve armature assembly for actuating a fuel injector.

From the illustration according to 1 it turns out that a fuel injector 10 a holding body 12 having. The holding body 12 of the fuel injection tors 10 is on a screw connection 102 with a nozzle retaining nut 22 connected. In the nozzle retaining nut 22 are a nozzle body 20 , an overlying throttle plate 18 as well as an overlying valve body 14 inserted. The nozzle retaining nut 22 is at the screw connection 102 with an external thread of the holding body 12 of the fuel injector 10 screwed. By applying a defined tightening torque to the nozzle retaining nut 22 the introduction of an axial force takes place in the screw connection, comprising the holding body 12 , the valve body 14 , the throttle plate 18 and the nozzle body 20 , The components mentioned are pressed against each other at their respective contact surfaces to form sealing points and in the mounted state, the fuel injector 10 dar. While in the nozzle body 20 a preferably needle-shaped injection valve member 24 is received, is in the holding body an actuator 26 recorded, which is designed as a solenoid valve. The components of the solenoid valve 26 are in a cavity 28 of the holding body 12 of the fuel injector 10 , Through the holding body 12 , the valve body 14 and the throttle plate 18 runs a high-pressure inlet 30 in a hydraulic room 72 of the nozzle body 20 empties.

In the high pressure inlet 30 There is a system pressure under which the fuel with which the fuel injector 10 over the high pressure inlet 30 is set, is set. The system pressure in a high-pressure accumulator injection system in a high-pressure accumulator body (common rail) can be brought to a magnitude between 1600 and 2000 bar by a high-pressure pump assigned to it, for example. The system pressure can also be a pressure to which the fuel is brought in the context of a pump-nozzle system (UI concept).

In the cavity 28 of the holding body 12 there is a magnetic core 36 having a through hole. Through the passage opening of the magnetic core 36 extends a closing spring 34 which is a plan side of an anchor plate 46 an anchor assembly 44 applied. The passage opening in the magnetic core 36 Aligns with a leak oil drain 32 , the low pressure side in the holding body 12 of the fuel injector 10 is trained. In the magnetic core 36 is a magnetic coil 40 taken up, via an electrical contact 38 can be applied with voltage. The magnetic coil 40 lies on a front side 42 ie the underside of the magnetic core 36 ,

The inventively proposed anchor assembly 44 includes the already mentioned anchor plate 46 that over the closing spring 34 is charged. The anchor plate 44 is at a first joint 74 with one in the embodiment according to 1 spherical shaped valve element 48 cohesively connected. The cohesively formed joint 74 between the anchor plate 46 and the here spherically formed valve element 48 can be formed, for example, as a welding or as a solder joint or the like.

The in the anchor assembly 44 integrated, here spherical shaped valve element 48 is at a further, second also cohesively formed joint 76 with a substantially cylindrically shaped guide body 52 cohesively connected. The anchor assembly 44 the in 1 illustrated first embodiment of the proposed solution according to the invention essentially comprises the component anchor plate 46 , spherical valve element 48 and in the valve body 14 guided leadership body 52 ,

As shown in the illustration 1 further, the valve element is 48 of the switching valve for actuating the in 1 illustrated fuel injector 10 designed as a simple switching valve. This means that the concept underlying the solution proposed by the invention in the first embodiment is a spherically formed valve element 48 a first seat 50 releases or closes. The first seat 50 is above a confluence point 58 a drainage channel 56 in the valve body 14 of the fuel injector 10 educated.

In the valve body 14 of in 1 illustrated fuel injector 10 runs below the cylindrically shaped guide body 52 an overflow channel 54 , About the leakage in the low pressure side area, ie the cavity 28 of the holding body 12 is forwarded.

The in the high-pressure inlet 30 pending fuel under system pressure flows through the holding body 12 , the high-pressure line section, in the valve body 14 ver runs over the throttle plate 18 the hydraulic room 72 to. In the hydraulic room 72 of the nozzle body 20 is located by a reference number 64 marked control room by a control chamber sleeve 66 is limited. The head of the preferably needle-shaped injection valve member 24 surrounding control chamber sleeve 66 is by a spring 68 charged with a covenant 70 the preferably needle-shaped injection valve member 24 supported. This is the control chamber sleeve 66 with a biting edge on the lower plan side of the throttle plate 18 hired. The fuel under system pressure flows into the control room 64 over the high pressure inlet 30 with the interposition of an inlet throttle 62 to. A pressure relief of the control room 64 takes place via the opening of the valve element 48 , d. H. its withdrawal from the first seat 50 , This will be the confluence 58 in the valve body 14 at which the drainage channel 56 opens released and a tax amount flows through the outlet throttle 60 from the control room 64 over the drainage channel 56 , the estuary 58 at the open valve element 48 passing into the low pressure side cavity 28 from and from there into the low pressure side drain 32 ,

The functioning of in 1 shown first embodiment of the present invention proposed fuel injector 10 Is as follows:
When the solenoid is energized 40 becomes the plan side of the anchor plate 46 the anchor assembly 44 to the front side 72 of the magnetic core 36 dressed. Due to the cohesive connection between the anchor plate 46 and the ball-shaped valve element 48 at the joint 74 becomes the ball-shaped valve element 48 from the first seat 50 drawn.

This will be the drain channel 56 opened and a tax amount from the tax room 64 flows into the drain 32 over the cavity 28 from. Due to the pressure relief of the control room 64 moves the end face of the preferred needle-shaped injection valve member 24 in the control room 64 into it, so in 1 not shown, at the combustion chamber end of the fuel injector 10 provided injection openings are opened. As a result, fuel under system pressure can reach the injection ports via the high-pressure line 30 flows in, are injected into the combustion chamber of the internal combustion engine.

Is the energization of the solenoid 40 that about the electrical contact 38 takes place, interrupted, then the anchor plate 46 the built anchor assembly 44 due to the action of the closing spring 34 pressed down. This will do that with the anchor plate 46 cohesively joined, spherically formed valve element 48 back in the first seat 50 in the valve body 14 put and the pressure relief of the control room 64 over the drainage channel 56 completed. Due to the continuous admission of fuel under system pressure, this fuel builds up in the high pressure inlet 30 and the inlet throttle 62 Pressure on which the end face of the preferably needle-shaped injection valve member 24 charged and this moves back into its combustion chamber side seat. This will be at the combustion chamber end of the fuel injector 10 provided injection openings closed again.

The switching valve shown in the first embodiment of the invention of the invention solution with the trained as described above armature assembly 44 , represents a switching valve which can be produced very inexpensively, which is particularly useful in the case of fuel injectors actuated by means of a solenoid valve 10 can be used.

The representation according to 2 is a further embodiment of the inventively proposed, preferably be actuated by means of a solenoid valve fuel injector.

Out 2 shows that in this embodiment, too, the fuel injector 10 the holding body 12 , the valve body 14 , the throttle plate 18 , the nozzle body 20 as well as the nozzle retaining nut 22 having. The nozzle retaining nut 22 is with the holding body 12 at the screw connection 102 together. When applying the nozzle retaining nut 22 With a defined tightening torque, the initiation of an axial force in the Schraubverband the fuel injector 10 comprising the holding body 12 , the valve body 14 , the throttle plate 18 as well as the nozzle body 20 , Also in this second embodiment of the proposed solution according to the invention is in the nozzle body 20 of the fuel injector 10 a preferably needle-shaped injection valve member 24 added. The operation of the fuel injector 10 in the in 2 illustrated second embodiment is preferably via an actuator 26 in the form of a solenoid valve, which in the cavity 28 of the holding body 12 is arranged. Analogous to in 1 already shown first embodiment, is located within the cavity 28 the magnetic core 26 , in turn, the magnetic coil 40 is embedded, which passes through the holding body 12 extending electrical contact 38 is currentable. In addition, extends through the holding body 12 both part of the high-pressure inlet 30 as well as the drainage 32 , In the passage opening of the magnetic core 36 is the closing spring 34 added.

In the in 2 shown second embodiment of the solution proposed by the invention is located below the valve body 14 analogous to in 1 dargestell th first embodiment, the throttle plate 18 , in which the outlet throttle 60 entering the drain channel 56 is integrated, executed and the inlet throttle 62 about which the control room 64 in the nozzle body 20 is pressurized with fuel under system pressure. The control room 64 is also in this embodiment of the control chamber sleeve 66 bounded, in turn, by the spring 68 who are on the fret 70 of the injection valve member 24 supports, against the lower plan side of the throttle plate 18 is placed. The high pressure inlet 30 that holds both the holding body 12 as well as the valve body 14 and the throttle plate 18 pervades, flows into the hydraulic space 72 at the top of the nozzle body 20 ,

In contrast to the formation of the switching valve in 1 , which is designed as a simple switching switching valve, is in 2 a double-switching switching valve for actuating the fuel injector 10 shown. The anchor assembly 44 comprises the ball-shaped valve element 48 , which both in the first seat 50 that in the valve body 14 is formed, can be placed, as well as in an intermediate position between this first seat 50 and another, second seat 82 standing in a plate lid 80 above the valve body 14 is trained.

Unlike in 1 illustrated embodiment of the armature assembly 44 includes the in 2 dargstellte anchor assembly 44 next to the valve body 14 guided leadership body 52 and the spherical valve element 48 an anchor bolt 88 , At the anchor bolt 88 is the anchor plate 46 added. This is located on a lock washer 84 in turn, from a safety sleeve 86 is overrun. Between the top of the locking sleeve 86 at the anchor bolt 88 runs a stroke 96 (h) to a resilient stop 90 , The springy stop 90 is as a pot-shaped use 92 in the through hole of the magnetic core 36 formed in which a the resilient stop 90 forming ring element via a biasing spring 94 is charged. The biasing spring 94 supported on the one hand on the holding body 12 off and is concentric to the drainage 32 arranged. On the other hand, the biasing spring acts 94 one in the cup-shaped insert 92 inlaid ring of the resilient stop 90 represents. Between the bottom of the resilient stop 90 and the top of the locking sleeve 86 runs the stroke 96 (Reference h). The springy stop 90 defines the intermediate switching position of the valve element 48 , ie the switching valve in an intermediate position between the first seat 50 and the other, second seat 82 ,

From the illustration according to 2 goes beyond that, in this embodiment, the anchor bolt 88 with the here spherically formed valve element 48 at the joint 74 cohesively joined, and the ball-shaped Ventilele ment 48 at the other, second joint 76 with the substantially cylindrical guide body 52 is added. The cylindrically shaped guide body 52 has a recess, which the mouth point 48 of the drainage channel 56 is arranged opposite. Below the guide diameter of the cylindrically shaped guide body 52 in the valve body 14 runs overflow channel 54 , about the discarded amount through the plate lid 80 in the cavity 28 of the holding body 12 can be initiated from where the discarded fuel via drain drain 32 enters the low-pressure side region of the fuel injection system.

According to the energization of the solenoid 40 preferably designed as a solenoid valve actuator 26 , can be realized with the inventively proposed switching valve several switch positions.

When closed, the ball-shaped valve element 48 when the solenoid is not energized 40 in the first seat 50 of the valve body 14 posed. This is the mouth point 58 of the drainage channel 56 locked. There is no tax amount from the tax room 64 in the nozzle body 20 deactivated, the injection valve member 24 closes the at the combustion chamber end of the fuel injector 10 provided injection port.

Will the solenoid coil 40 from the magnetic core 36 is enclosed, via the electrical contact 38 energized, then the anchor plate 46 dressed. This attaches to the lock washer 84 and pull the anchor bolt 88 with attached, spherical shaped valve element 48 from the first seat 50 , This results in a first pressure relief of the control room 64 , In this first switching position of the switching valve proposed according to the invention, very small pre-injection quantities can be achieved. Starting from this first switching state, by the stroke 96 between the locking sleeve 86 and the resilient stop 90 is defined, can further energization of the magnetic core 36 enclosed magnetic coil 40 be made. Will with stronger energization of the solenoid 40 the Zwischenhubanschlag, ie the stroke 96 (h) overcome, so is the ball-shaped valve element 48 in the second seat 82 in the plate lid 80 above the valve body 14 is accommodated, so that the pressure relief of the control room due to the closed second seat 82 finished.

From the first switching position, ie the opening of the first seat 50 in the valve body 14 and the associated injection of small amounts of pilot injection into the combustion chamber, the switching valve proposed in the invention can be in the in 2 shown second embodiment, very quickly in the by the Zwischenhubanschlag 90 switch through defined intermediate position and bring in this position, the main injection amount of fuel under system pressure in the combustion chamber of the internal combustion engine. By the in 2 illustrated second embodiment of the proposed solution according to the invention can be a kompaktbauende very fast-switching and force-balanced actuator assembly including a solenoid valve for actuating a fuel injector 10 realize.

Also at the in 2 shown, used in the context of the switching valve armature assembly 44 , prefabricated components, such as the ball-shaped valve element 48 be used. In contrast to the design of the armature assembly 44 according to the embodiment in 1 has the in 2 illustrated armature assembly 44 next to the anchor plate 46 , the ball-shaped valve element 48 and the cylindrical guide body 52 , the anchor bolt 88 , the lock washer 84 and the surrounding safety sleeve 86 on. Due to the double switching function of in 2 shown valve element 48 is in this embodiment additionally the resilient stop 90 provided, which the intermediate switching position of the ball-shaped valve element 48 between the first seat 50 and the second seat 82 Are defined.

Detail X (compare 2 ) it can be seen that the cup-shaped use 92 a wall 100 has, in the at least one opening 98 is provided, which controlled amount of the cavity 28 of the holding body through in the leak oil drain 32 to be able to flow. From detail X also shows that the resilient stop 90 on one edge of the wall 100 the cup-shaped insert 92 rests and by in detail X only indicated biasing spring 94 is charged. In detail X is also the stroke 96 represented by which the armature assembly 44 to reach the through the resilient stop 90 defined center position is to move in a vertical direction.

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 19650865 A1 [0001, 0002]
• - DE 19708104 A1 [0002]

Claims (10)

Fuel injector ( 10 ) with a holding body ( 12 ), with a nozzle body ( 20 ), in which a by means of an actuator ( 26 ), in particular by means of a solenoid valve, actuated preferably needle-shaped injection valve member ( 24 ), with an armature assembly ( 44 ) via the actuator ( 26 ), in particular a solenoid valve is actuated, which the pressure relief or pressurization of a control room ( 64 ), characterized in that in the armature assembly ( 44 ) with at least one seat ( 50 . 82 ) cooperating valve element ( 48 ) is integrated. Fuel injector ( 10 ) according to claim 1, characterized in that in the anchor assembly ( 44 ) integrated valve element ( 48 ) is spherical. Fuel injector ( 10 ) according to claim 1, characterized in that in the anchor assembly ( 44 ) integrated valve element ( 48 ) at a first joint ( 74 ) with an anchor plate ( 46 ) or an anchor bolt ( 88 ) and at a second joint ( 76 ) with a guide body ( 52 ) is added. Fuel injector ( 10 ) according to claim 3, characterized in that the joints ( 74 . 76 ) are formed as cohesive joints, in particular welded joints. Fuel injector ( 10 ) according to claim 1, characterized in that the valve element ( 48 ) between a first seat ( 50 ) in the valve body ( 14 ) and another second seat ( 82 ) in a by a resilient stop ( 90 ) defined intermediate switching position is switchable. Fuel injector ( 10 ) according to claim 1, characterized in that the armature assembly ( 44 ) next to the valve element ( 58 ) and the guide body ( 52 ) one on an anchor bolt ( 88 ) guided anchor plate ( 46 ) fitted with a lock washer ( 84 ) cooperates. Fuel injector ( 10 ) according to claim 5, characterized in that the intermediate switching position of the valve element ( 48 ) by a resilient stop ( 90 ) is defined. Fuel injector ( 10 ) according to claim 7, characterized in that the resilient stop ( 90 ) a cup-shaped insert ( 92 ) comprising a biasing spring ( 94 ) enclosing the holding body ( 12 ) of the fuel injector ( 10 ) and the resilient stop ( 90 ). Fuel injector ( 10 ) according to one or more of the preceding claims, characterized in that the intermediate switching position of the ball-shaped valve element ( 48 ) after passing through a stroke ( 96 ) between a plane surface ( 86 ) of the armature assembly ( 44 ) and the achievement of the resilient stop ( 90 ) is reached. Fuel injector ( 10 ) according to one or more of the preceding claims, characterized in that the first seat ( 50 ) in the valve body ( 14 ) above the mouth ( 58 ) one the control room ( 64 ) pressure-relieving drainage channel ( 56 ) is formed and the further, second seat ( 82 ) on a plate lid ( 80 ) is executed.