DE102012010268A1 - Fuel injection method using injector of fuel injection system for e.g. Otto engine of vehicle, involves enables prevention of fixed seating of rod assembly by generating excited vibration of actuator - Google Patents

Abstract

The injector (1) is provided with an actuator (10) and a pivot valve (2). The valve element (7) of pilot valve is selectively pushed against the valve seat (6) over rod assembly (8) on which an anchor portion (12) of the actuator is acted. The prevention of fixed seating of rod assembly is enabled by generating excited vibration of actuator. An independent claim is included for a fuel injector.

Description

The present invention relates to a method for use with an injector according to the preamble of claim 1 and a method for use with an injector according to the preamble of claim 6.

In generic injectors for fuel injectors, it may happen that stuck after prolonged downtime valve members and / or transmission members of the pilot valve. In particular, when the oxidation stability of the fuel, for. B. biofuel, is low, deposits can z. B. by polymerization in the low-clearance guides cause sticking by gluing. The bond can be so strong that the injector does not start or inject any more when the engine starts up after applying the high pressure.

Proceeding from this, the present invention has the object to provide a method which overcomes the disadvantages of the prior art and allows loosening of the fixed valve element and / or prevents sticking and a method which prevents correspondingly sticking.

This object is achieved by the features of claim 1 and of claim 6.

Advantageous developments and embodiments of the respective method according to the invention are specified in the subclaims.

According to the invention, a method for use with an injector is proposed, wherein the injector has an actuator and a valve, preferably a solenoid actuator and furthermore preferably a pilot valve. The injector may preferably be provided for use in a fuel injection system, in particular a common rail system, wherein the injector is generally intended for use with internal combustion engines in the form of gasoline or diesel engines, in particular large diesel engines and further in particular vehicle engines, for example in offroad or ship applications.

The injector is configured such that a valve member of the valve can be selectively urged against a valve seat via a rod arrangement, against which an armature part of the actuator can act, for which purpose in particular a spring element (compression spring) of the actuator is provided. In the course of energization of the actuator, in particular its solenoids, the rod assembly can be relieved anchoring member side, wherein the anchor member is preferably attracted to the magnetic part and the pressure force of the compression spring is overcome, so that the valve can open. Here, the rod assembly with the anchor part is unconnected.

The rod arrangement can be formed by means of a valve rod, at the end remote from the armature part of the valve member or preferably be formed for example by means of a valve rod and a transmission rod, which in each case in an (axial) leadership are included, for example in a (axial) )Drilling. The transmission rod can be arranged between the anchor part and the valve rod.

In order to avoid the rod assembly in the event of sticking, in particular due to fuel in the guide, and / or to prevent sticking, in particular due to fuel in the guide, the rod assembly is within the scope of a (first) proposed method according to the invention by means of the actuator , in particular of the anchor part, subjected to a shock sequence, further hammered in particular by means of the anchor part. For this purpose, the actuator is preferably operated clocked. The process can be carried out continuously over a period or z. B. at intervals. By virtue of the method, adhesions can thus advantageously be simply disrupted or avoided.

The method making use of the impact sequence is carried out by means of the injector on an internal combustion engine, in particular when it is at a standstill or before commencement of injection operations. For example, as part of the proposed method, a step may be provided which precedes the impact sequence, the step of causing the engine (engine) to be towed up by the starter, i. H. to allow a starting pressure build-up, which additionally acts against the stuck rod assembly and can support for a particular faster release.

In the context of the above-described method, the actuator for supplying the rod assembly with the impact sequence is preferably energized with current pulses, in particular uniform and furthermore preferably rectangular or approximately rectangular current pulses. Optionally, the current pulses may each comprise an initial peak or boost peak, which preferably have the same height over the current pulses. It is proposed in particular to energize the actuator (solenoid) with current pulses at a distance of half a period relative to a natural frequency of a system capable of oscillating from its spring element (pressure spring) and its armature part. Such can the Energy consumption for a particular impact sequence are kept advantageously low.

Preferably, the impact sequence is generated by means of at least one first current pulse of a first amplitude and subsequently at least one second, in particular a plurality of second current pulses of a second, compared to the first amplitude reduced amplitude.

Further preferably, the second current pulses may have a constant second amplitude. Such can z. B. be detected on a release in the course of a shock sequence, when a detected current to the solenoid or actuator shows a corresponding with the successful dissolution (expected) course. The shock sequence can be terminated in this respect based on a detected current profile, alternatively z. B. after a predetermined period. The current pulses can be initiated or generated, for example, by means of a control device of a fuel injection device.

According to a further aspect of the present invention, a method is also proposed for use with an injector as described above, wherein the actuator is excited to avoid oscillation of the rod assembly, in particular by means of a sinusoidal current. The vibration excitation can z. B. be provided over a longer period, for. B. take place at intervals.

The vibration excitation can prevent sticking (sticking) with a low expenditure of energy even in longer downtimes of the injector or an internal combustion engine, in particular due to a structure-borne sound excitation of the injector accompanying the excited vibration (flexural vibration, eg the armature plate) transfers to the valve. In addition, the application of a shock sequence as described above may be provided, for example, in alternation with the vibration excitation. Preferably, the impact sequence z. B. a vibrational excitation ahead.

The excitation of the actuator to a vibration, in particular with a sinusoidal current, preferably takes place with a natural frequency (stroke natural frequency) of the oscillatory system of the spring element and the anchor part, in particular without lifting the anchor part from its rest position, i. e. on the rod assembly adjacent to allow. In this case, advantageously only low energy or only a small amount of electricity is needed.

Alternatively or additionally, an excitation of an actuator element of the actuator to a vibration, in particular with a natural frequency and further in particular first order, in particular its spring element or anchor part, be provided, d. H. by suitable energization of the actuator (solenoid). The excited vibrations, i. e. In particular, bending vibrations, can ever be transferred to the rod assembly and prevent sticking or stuck.

A fuel injection device with an injector as described above is also proposed within the scope of the present invention, the fuel injection device being designed to carry out the above-described method making use of the impact sequence and / or the vibration excitation, in particular by means of a control device.

The injector of the fuel injection device or for an internal combustion engine preferably comprises a rod arrangement with a valve rod and a transmission rod, which are each guided in a guide on or in the injector. In this case, a stiffness of the spring element acting against the transmission rod is preferably smaller than the rigidity of the transmission rod and / or the rigidity of the transmission rod is greater than or equal to a stiffness on the valve rod, in particular an exposed portion. It is generally provided that the rod arrangement enables elastic compression, in particular for this purpose has a free length or an exposed portion.

In a preferred embodiment of the fuel injection device or of an injector, at least one cutout is formed in the guide of the rod arrangement, preferably as an annular space around the rod arrangement, which further impedes sticking, in particular by reducing mutually immediately adjacent surfaces.

Further features and advantages of the invention will become apparent from the following description of embodiments of the invention, with reference to the figures of the drawings, which show details essential to the invention, and from the claims. The individual features can be realized individually for themselves or for several in any combination in a variant of the invention.

Exemplary embodiments of the invention are explained below with reference to the accompanying drawings. Show it:

1 exemplary and schematic details of an injector for carrying out the method according to a possible embodiment of the invention;

2a exemplary and schematic details of an injector for carrying out the method according to another possible embodiment of the invention;

2 B exemplary and schematically a model corresponding to the injector according to 2a ;

3 a diagram illustrating the current and stroke during a shock sequence example.

In the following description and the drawings, the same reference numerals correspond to elements of the same or comparable function.

1 shows schematically and exemplarily details of an injector 1 according to a first embodiment for carrying out the method according to the invention described below.

The injector 1 , preferably in the form of an injector for biofuel, for example also provided for diesel and heavy oil, comprises a pilot valve 2 (Servo control valve) via which a control room 3 of the injector 1 can be selectively relieved of pressure. Depending on the pressure in the control room 3 can be a nozzle needle of the injector 1 , not shown, to be moved.

High-pressure fuel can flow out of the control room 3 when opening the valve 2 via a throttle 4 be discharged, ie in a leakage discharge, not shown, so that the nozzle needle can lift off its seat. When the valve is closed 2 , ie in the in 1 and 2 shown position, the system high pressure, arrow A, in the control room 3 be constructed, ie via a communicating high-pressure fuel line, not shown.

The pilot valve 2 , which in a housing or body 5 of the injector 1 is received, is by means of a valve seat 6 and a valve member 7 formed, wherein the valve member 7 at the end 8-1 a bar arrangement 8th is arranged or formed, in particular integrally therewith. In the course of a movement of the rod assembly 8th in the direction indicated by the double arrow B axial direction, the valve member 7 from the seat 6 take off or be pushed against it. The bar arrangement 8th is here in an axial guide 9 , ie a hole, on the injector 1 recorded, ie with little play.

The bar arrangement 8th is in this embodiment of the injector 1 by means of a (single, one-piece) rod 8a formed, ie a valve stem 8a , The pole 8a is in this case made in particular of a material which is not magnetizable, preferably made of a stainless steel.

About the bar arrangement 8th . 8a , can be an actuator 10 of the injector 1 the valve member 7 selectively in the seat 6 push, as explained in more detail below.

The actuator 10 is by means of a magnetic packet or solenoids 11 , an anchor part 12 , and a spring element 13 educated. The anchor part 12 which is an anchor plate 12a with an anchor rod 12b is covered by the compression spring 13 towards the bar assembly 8th . 8a crowded, with the anchor part 12 with the bar arrangement 8th . 8a however, no firm connection is received.

In a first state, in which the magnetic packet 11 is not energized, urges the anchor rod 12b in this case against the valve seat 6 opposite end 8-2 the bar arrangement 8th . 8a and thus the valve member 7 , ie by means of the spring force of the spring element 13 , in the valve seat 6 , This condition corresponds to z. B. also a depressurized or idle state of the injector 1 in which the pilot valve 2 by means of the spring force of the spring element 13 permanently closed, ie de-energized.

In a second state, in which the magnetic packet 11 is energized, ie B. by an associated fuel injection device, not shown, the anchor part 12 from the magnetic package 11 magnetically attracted (stroke), wherein the spring force of the compression spring 13 is overcome. That the valve seat 6 opposite end 8-2 the bar arrangement 8th . 8a is depressurized. In a pressureless state of the injector 1 , z. B. at standstill of an internal combustion engine, in which no system high pressure against the valve seat end 8-1 the bar arrangement 8th . 8a acts, the anchor part can 12 when energizing the magnet package 11 this from the system on the rod assembly 8th . 8a solve and remove from it, ie from the end 8-2 ,

1 further illustrates that the rod assembly 8th . 8a at the seat 6 facing the end 8-1 over an axial section 14 is free. The granted free space 14 advantageously allows elastic compression of the rod assembly 8th . 8a in the context of the method described below for acting on the bar arrangement 8th . 8a with a burst.

2a shows a further preferred embodiment of an injector 1 for use with the proposed methods, wherein the rod assembly 8th is formed in several parts, in particular in two parts. The bar arrangement 8th according to 2a includes next to a valve stem 8a continue a transmission rod 8b , which with greater clearance than the valve rod 8a in the axial guidance 9 is arranged. The bars 8a and 8b are in this case unconnected to each other, the rod assembly 8th Furthermore, no firm connection with the anchor part 12 received. The bar arrangement 8th can as in the embodiment of the injector described above 1 especially not from the anchor part 12 (active) are tightened (hub).

In the embodiment according to 2a , further exemplified by 2 B , Is further provided that a stiffness c ₀ against the transmission rod 8b acting spring 13 , smaller, in particular much smaller than the stiffness c _{1 of} the transmission rod 8b , Further, the rigidity c _{2 of} the exposed portion 14 the valve rod 8a chosen to be less than or equal to c ₁ , in particular <0.5 c ₁ .

The methods according to the invention are described below in conjunction with the embodiments of the injector described above 1 explained in more detail.

To avoid that in the course of prolonged downtime, ie corresponding to long-lasting closing conditions of the valve 2 , Fuel for sticking the rod assembly 8th ( 8a respectively. 8b ) in the lead 9 leads and / or a release of the stuck rod assembly 8th to effect the bar assembly 8th according to the first proposed method by means of the actuator 10 subjected to a shock sequence, in particular by means of the anchor part 12 behämmert. In this way, bonding can be avoided or disrupted step by step.

As part of a respective shock of the shock sequence of the anchor part 12 by energizing the magnet package 11 (Sol) thereby attracted (stroke) and subsequently released by interrupting or terminating the energization, so that this by the action of the spring 13 against the bar arrangement 8th or their the actuator 10 facing the end 8-2 beats, ie corresponding to a hammer blow.

By way of example, a dissolution process will be described below in conjunction with 2a and 2 B such as 3 , which latter illustrates a stroke and current course in a shock sequence, explained in more detail. In 3 In this case, the upper diagram represents the current I at the actuator 10 (Solenoid) over the time t, the lower diagram shows the stroke h of the anchor part 12 over time t.

In order to be able to achieve above-mentioned effects with advantageously low expenditure of energy, the actuator becomes 10 ie the magnetic package 11 for loading the rod assembly 8th energized with the impact sequence or impact sequence with current pulses I1, I2, I3,... 3 , In particular, uniform current pulses, which in each case in particular at a distance of half a period (T / 2) based on a natural frequency f _{0 of} the oscillatory system consisting of the anchor part 12 and the spring 13 on the actuator 10 be created, sa 3 ,

wobei m die Masse des Ankerteils 12 und c₀ die Federsteifigkeit der Feder 13 bezeichnet.By impressing the current pulses I1, I2, I3, ... the same clock frequency, the oscillatory system from the anchor part 12 and the spring 13 be swung with little energy, in particular with the frequency

where m is the mass of the anchor part 12 and c _0, the spring constant of the spring 13 designated.

An impact sequence, see a. 3 , is introduced by means of a first rectangular or nearly rectangular current pulse I1 a first, relative to the other current pulses I2, I3, ... large amplitude, optionally optionally with an (initial) boost peak (dashed in the upper view of 3 ), (the other current pulses I2, I3 can also each have an (initial) boost peak (dashed in FIG 3 ), wherein the boost peaks over the pulses I1, I2, I3, ... preferably have the same height (ΔI)).

The first supply of I1 turns the anchor part 12 brought to the height h1 (stroke), z. B. in contact with the magnetic package 11 , and subsequently released. As a result of release the anchor part strikes 12 or the mass m like a hammer back on the transmission rod 8b , where the shock pulse on the (stuck) valve rod 8a is forwarded. There is the impact force, sa 2 B to the actuator 10 directed clamping or friction force F _{R, o} in the axial direction opposite. Since the force of the shock pulse is always greater than F _{R, o} , the valve stem leads 8a a relative movement, the amount of the stiffness c _{2 of} the free length 14 and the strength of the force required to break the bond is.

des schwingungsfähigen Systems, wird ein weiterer, zweiter Stromimpuls I2 am Aktuator 10 angelegt, s. a. 3, welcher eine gegenüber I1 verringerte Amplitude aufweist.After the impact of the anchor part 12 on the pole assembly 8th , ie after half a period T / 2 based on a natural frequency

of the oscillatory system, is another, second current pulse I2 on the actuator 10 created, sa 3 , which has a reduced amplitude compared to I1.

Obvious is the resulting stroke h2 of the anchor part 12 Compared to the first stroke h1 reduced here, since the tracked lower energy is not sufficient to reach the lifting height h1 again and also a relatively large part of the energy is consumed by an induced relative movement against the initially high resistance opposing bonding.

With the renewed rebound of the anchor part 12 at time T, another second pulse I3 on the actuator 10 whose amplitude corresponds to that of the further second pulses I4,... and that of the second pulse I2. The tracked energy now allows a h2 enlarged stroke, since the now already attacked bonding can only oppose a reduced resistance. With each stroke so that a (minute) relative movement takes place, whereby the valve stem 8a is compressed and at least partially spring back. The bond is gradually broken, whereby the breakout force is always lower.

With increasing number of pulses, ie corresponding to a final release of the stuck bar assembly 8th , a corresponding lifting height h of the anchor part 12 one whose achievement in one at the Solenoiden 11 Recorded current waveform is detected. Along with the detection, the burst is terminated. Alternatively, the burst sequence may be terminated after a predetermined period, for example.

The method is preferred before a start of operation of the injector 1 , ie performed for the purpose of injection processes, in particular starting from or in a non-pressurized state of the injector 1 ,

To avoid sticking the bar assembly 8th can the actuator 10 be excited in the context of the present invention according to the method described below, alternatively or in addition to a vibration, in particular by means of a sinusoidal current. This will be the actuator 10 with a natural frequency of the oscillatory system of anchor part 12 and the spring 13 excited to a vibration, in particular without lifting the anchor part 12 from its rest position, ie the attachment to the rod assembly 8th to enable. The excited vibration causes the injector to experience 1 a structure-borne noise, which extends to the pilot valve 2 transfers.

Alternatively or additionally, the actuator 10 with the natural frequency of the first order of the spring 13 or the anchor part 12 be excited to a vibration, ie ever by means of a sinusoidal current. The feather 13 or the anchor part 12 starts to vibrate or whirring.

The method making use of the vibrational excitation can be carried out besides the method making use of the impact sequence. The method is preferred before a start of operation of the injector 1 , ie performed for the purpose of injection processes, in particular starting from or in a non-pressurized state of the injector 1 ,

The respective method can be carried out by means of a fuel injection device which comprises an injector as explained above 1 has, in particular by means of a control device of the fuel injection device. Such can be in particular the energization of the actuator 10 within the framework of the respective procedure.

As a further measure to prevent sticking can in the leadership 9 the respective bar arrangement 8th at least one cut-out 15 , Preferably in the form of an annular space around the rod assembly 8th around, be formed.

LIST OF REFERENCE NUMBERS

1

injector

2

pilot valve

3

control room

4

throttle

5

casing

6

valve seat

7

valve member

8th

rod assembly

8-1

The End

8-2

The End

8a

valve rod

8b

transmission rod

9

guide

10

actuator

11

Magnetic Package (Solenoid)

12

anchor part

12a

anchor plate

12b

anchor rod

13

spring element

14

Free length

15

cutout

A

high pressure

B

axial direction

Claims (12)

Method for use with an injector ( 1 ), the injector ( 1 ) an actuator ( 10 ) and a valve ( 2 ), in particular a pilot valve ( 2 ) whose valve member ( 7 ) via a bar arrangement ( 8th ) against which an anchor part ( 12 ) of the actuator ( 10 ) can act selectively against a valve seat ( 6 ) is pushable, wherein the rod assembly ( 8th ) with the anchor part ( 12 ) is unconnected, characterized in that the rod assembly ( 8th ) in the event of a stuck fit for a release and / or to avoid sticking by means of the actuator ( 10 ) is subjected to a shock sequence, in particular by means of the anchor part ( 12 ) is hammered. Method according to claim 1, characterized in that the actuator ( 1 ) further comprises a spring element ( 13 ), which together with the anchor part ( 12 ) forms a vibratory system, wherein the actuator ( 10 ) is energized to act on the impact sequence with current pulses, in particular at a distance of half a period relative to a natural frequency of the oscillatory system. Method according to one of the preceding claims, characterized in that the impact sequence by means of at least one first current pulse (I1) of a first amplitude and subsequently at least a second, in particular a plurality of second current pulses (I2, I3, ...) a second, compared to the first Amplitude reduced amplitude is generated. A method according to claim 3, characterized in that the first (I1) and the second (I2, I3, ...) current pulses are uniform, the second current pulses (I2, I3, ...) in particular have constant second amplitudes. Method according to one of the preceding claims, characterized in that the impact sequence is terminated as a function of a detected current profile or after a predetermined duration. Method for use with an injector ( 1 ), the injector ( 1 ) an actuator ( 10 ) and a valve ( 2 ), in particular a pilot valve ( 2 ) whose valve member ( 7 ) via a bar arrangement ( 8th ) against which an anchor part ( 12 ) of the actuator ( 10 ) can act selectively against a valve seat ( 6 ) is pushable, wherein the rod assembly ( 8th ) with the anchor part ( 12 ) is unconnected, characterized in that the actuator ( 10 ) to avoid sticking the rod assembly ( 8th ) is excited to a vibration, in particular by means of a sinusoidal current. Method according to claim 6, characterized in that the actuator ( 10 ) further comprises a spring element ( 13 ), which together with the anchor part ( 12 ) forms a vibratory system, wherein the actuator ( 10 ) is excited with a natural frequency of the oscillatory system to a vibration, in particular without lifting the anchor part ( 12 ) from its rest position. Method according to claim 6, characterized in that an actuator element ( 12 . 13 ), in particular its spring element ( 13 ) or anchor part ( 12 ) is excited to a vibration, in particular with a natural frequency of the first order. Fuel injection device with an injector ( 1 ), the injector ( 1 ) an actuator ( 10 ) and a valve ( 2 ), in particular a pilot valve ( 2 ) whose valve member ( 7 ) via a bar arrangement ( 8th ) against which an anchor part ( 12 ) of the actuator ( 10 ) can act selectively against a valve seat ( 6 ) is pushable, wherein the rod assembly ( 8th ) with the anchor part ( 12 ) unconnected, characterized in that the fuel injection device is designed for carrying out the method according to one of the preceding claims, in particular by means of a control device. Method according to one of claims 1 to 8 or fuel injection device according to claim 9, characterized in that the rod arrangement ( 8th ) a valve rod ( 8a ) or a valve rod ( 8a ) and a transmission rod ( 8b ), in particular each in a leadership ( 9 ) arranged. Fuel injection device according to claim 10, characterized in that in the guide ( 9 ) of the bar arrangement ( 8th ) at least one cut-out ( 15 ) is formed, in particular as an annular space around the rod assembly ( 8th ). Fuel injection device according to one of claims 10 to 12, characterized in that the rod arrangement ( 8th ) at the injector ( 1 ) an elastic compression is possible, in particular by means of a free length ( 14 ).

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