DE102005001427A1 - Method for correcting the injection behavior of at least one injector having a solenoid valve - Google Patents

Abstract

A method for correcting the injection behavior of at least one solenoid-valve-type injector by storing information about the at least one injector obtained by comparing target values with actual values at individually plural checkpoints of the at least one injector and controlling the at least one injector taking into account the stored information, is characterized in that is used as information of the stroke of the solenoid valve.

Description

The The invention relates to a method for correcting the injection behavior at least one, a solenoid valve having injector according to the preamble of claim 1.

electrical For example, driven injectors for injecting fuel become used in common rail systems. In the memory injection "common rail" are pressure generation and injection decoupled. The injection pressure is independent of The engine speed and injection quantity generated and is in the "rail" for the injection ready. The injection time and the injection quantity are in calculated by an electronic engine control unit and by an injector each engine cylinder over implemented a remote controlled valve. It comes through, for example a solenoid operated injectors are used. Such injectors have different due to their mechanical manufacturing tolerances Quantity maps. Under a quantity map is the name between injection quantity, rail pressure and activation time to understand. These different quantity maps lead to that despite electrically defined control every single injector the combustion chamber fills with different amounts of fuel. To one as possible Low fuel consumption in compliance with strict emission standards and to achieve a very good smoothness, the injectors are allowed to operate have only very small tolerances with regard to the injection quantity. These required low tolerances can due to the mechanical Manufacturing tolerances are not met. Nevertheless, a defined To ensure injection quantity at the injectors are the injectors after production at characteristic working points on their Measured injection quantity and divided into classes. The respective Class must be Engine control unit while be known to the operation of the injectors, so that the control of the special Characteristics of the class can be adapted injector specific. The class information is doing so in different ways on the injector stored, for example, by different codes, such as for example by barcode, by resistors at the injector or by Plain text on the injector. The class information is provided by a code recognition and subsequent programming transmitted to the controller. The classification of the injectors is advantageously carried out So that the Injectors at several test points in terms of injection quantity measurement.

From the DE 102 15 610 Now, a method is known which offers the advantage that the information is determined by comparing desired values with actual values and that this information is individually related to several test points of at least one injector. This gives the control unit accurate information about multiple test points or operating points of each injector. As a result, there is the possibility that the control duration is corrected by measures in the control unit individually for each injector depending on the target amount and rail pressure compared to a nominal characteristic map in order to come as close as possible to the target amount. In the case of this method, the control unit contains a plurality of, preferably four test values from production, for each injector. From these variables, a correction quantity map is built up. For this purpose, the quantity correction for a number of pressure / control combinations is determined from the deviations of the injection quantities from their desired values from the test values at these test points. This method is also advantageous because it provides the opportunity to allow greater tolerances on the manufacturing test values and thus increase the yield of the production.

at modern vehicle engines now need very short injection intervals will be realized. So is the distance between, for example, a pilot injection and a Main injection typically between about 200 to 450 μs. As with these short injection intervals In addition, very precise injection quantities are required, the above-described Injector quantity comparison (IMA), in which the setpoints with actual values are displayed different operating points are compared, each to two additional measuring points, namely a pilot injection and a main injection, extended. It has it has now been shown that the Meßwiederholstreuung of these two checkpoints is insufficient. The two additional test points also have longer cycle times for the exam required.

Of the The invention is therefore based on the object, a method for correcting the injection behavior of at least one, having a solenoid valve Educate injectors so that the Injektormengenabgleich also in the two additional measuring points pilot injection and Main injection is improved and reduces the cycle times for testing become.

Advantages of invention

These The object is solved by the features of claim 1.

The basic idea of the invention is the main influencing parameters of the stroke of the solenoid valve and the overstroke of the solenoid valve in the case of the above-described In to take account of jektormengenabgleich and store at each injection point as in addition the injection behavior of the injector determining information and to use for a later control of the injector. On the basis of this information, the correction amount of the injection valve is then determined.

The determined correction amount is at a direct to a pilot injection considered following main injection.

drawing

Further Advantages and features of the invention will become apparent below with reference on the attached Drawing, based on embodiments described in more detail.

In show the drawing:

1 a known from the prior art schematic representation of part of a common rail system, in which the inventive method is used;

2 a known from the prior art quantity correction map as a graph of the dependence of the injection amount of the rail pressure;

3 a schematic sectional view of a solenoid valve injector and

4a , b schematically shows the stroke over the time of the armature of the in 3 shown solenoid valve without (4a) and with (4b) overstroke.

description the embodiments

In 1 is the high-pressure wedge of the storage injection system common rail shown. In the following, only the main components and those components which are essential to the understanding of the present invention will be explained in more detail. The arrangement comprises a high-pressure pump 10 , which have a high pressure line 12 with the high-pressure accumulator ("rail") 14 communicates. The high-pressure accumulator 14 is about more high pressure lines 16 connected to the injectors. In the present illustration are a high pressure line 16 and an injector 18 shown. The injector 18 is installed in the engine of a motor vehicle. The illustrated system is powered by a motor controller 20 controlled. Through the engine control unit 20 in particular, a control of the injector 18 ,

At the injector 18 is a facility 22 provided for storing information which is customized to the injector 18 Respectively. The information in the facility 22 can be stored by the engine control unit 20 be taken into account, so that an individual control of each injector 18 can be done. Preferably, the information is correction values for the quantity map of the injector 18 , The device 22 for storing the information can be used as a data storage as one or more electrical resistors, as a barcode, by alphanumeric encryption or by one to the injector 18 arranged integrated semiconductor circuit be realized. The engine control unit 20 may also be a semiconductor integrated circuit for evaluation in the device 22 have stored information.

This in 2 The diagram shown shows a quantity correction map MKK, wherein one of the injector 18 metered amount M is plotted above the rail pressure P _{Ra il} . The quantity correction map MKK is based on several injection points (VL, EM, LL, VE). The adjustment values .DELTA.VL, .DELTA.EM, .DELTA.LL and .DELTA.VE are used for the amount correction M, which are determined by the comparison of desired values with actual values at different Raildrükken P _Rail at different test points. The adjustment values ΔVL, ΔEM, ΔLL and ΔVE may be assigned a correction value KW _(n) . By way of example, the injection quantity M at a test point P is assigned the adjustment value ΔEM as a function of a pressure (rail pressure / activation duration combination) of the injection EM, from which a correction quantity ΔQ _(n) for the control unit in the respective test point is determined. The calculated correction quantities ΔQ _(n) are based on the adjustment values, which are determined from quantity deviations ΔVL _{ABW (n)} , ΔEM _{ABW (n)} , ΔLL _{ABW (n)} and ΔVE _{ABW (n)} in the respective test points, and associated correction values KW _(n) . In 2 For example, the checkpoint P ΔEM is assigned a correction value KW _(n) .

There are numerous test points P for an injector 18 be provided, which arise over the entire operating range and the quantity correction map MKK. Between the reference points defined by test points, the adjustment values can also be linearly interpolated, so that ultimately a reliable fuel quantity measurement can be carried out over the entire operating range. The determination of the quantity correction ΔQ _(n) for the respective test point is in the DE 102 15 610 A1 , Column 6, lines 68 to column 8, line 61 described in detail. For the purpose of disclosure, reference is hereby expressly made to this publication. The quantity corrections are calculated as the sum of the products of the correction values KW _(n) and the quantity deviations ΔVL _{ABW (n)} , ΔEM _{ABW (n)} , ΔLL _{ABW (n)} and ΔVE determined from the desired value with the actual value comparison _{ABW (n)} to the respective Checkpoints calculated.

It find now at the various test points not just an injection, but two in very short spray intervals successive injections instead of. The dif ference time between the two injections is thereby typically 200 to 450 μs. It has now been shown that the second injection at these small spray intervals mainly through the adjustment parameters overtravel and Armature stroke of a two-part solenoid valve armature is affected. For this reason, in the investigation described above the correction quantities at each inspection point two additional ones Measuring points for each considered a pre-injection and a main injection. Many studies have now shown that the repeated measurement this in a sense Combi checkpoints insufficient is. About that also arise for the two additional ones checkpoints longer Cycle times for the so-called load test.

A sectional view of a solenoid valve injector, as used in a previously described common rail system is used schematically in 3 shown.

The fuel is from the rail 14 over the high pressure line 16 a high pressure connection 390 fed and from there via a high-pressure inlet channel 392 to an injection nozzle, also referred to as a nozzle needle 360 as well as via an inlet throttle 100 in a valve control room 350 guided. The valve control room 350 is via an outlet throttle 380 through a solenoid valve, formed by a magnetic coil 320 , one in an anchor guide 335 guided magnet armature 330 and a valve ball 340 , can be opened, with a fuel return 310 connected.

In the closed state of the outlet throttle 380 the hydraulic force predominates on a valve piston 110 against the force on a pressure shoulder 362 the nozzle needle 360 , As a result, the nozzle needle becomes 360 pressed into its seat and closes the high-pressure inlet channel 392 close to the (in 3 not shown) engine compartment. When the engine is not running and there is no pressure in the rail 14 , closes a nozzle spring 364 the injector.

When driving the solenoid valve, so the solenoid 320 and thus the magnet armature 330 and the valve ball 340 becomes the outlet throttle 380 opened by the valve ball 340 removed from their seat. The inlet throttle 100 prevents complete pressure equalization, so that the pressure in the valve control room 350 and thus the hydraulic force on the valve piston 110 sinks. Once the hydraulic force is applied to the pressure shoulder 362 the nozzle needle 360 acting force falls below, opens the nozzle needle 360 , The fuel now passes through spray holes 370 into a combustion chamber of the engine (in 3 not shown). When the solenoid valve is no longer actuated (solenoid coil 320 ) becomes the armature 330 by the force of the valve spring 322 pressed down (in closed position). The valve ball 340 closes the outlet throttle 380 , This builds up in the valve control room 350 via the inflow of the inlet throttle 100 again a pressure corresponding to the rail pressure. This increased pressure exerts a higher force on the valve piston 110 out, so that the nozzle needle 360 closes again. The flow of the inlet throttle 100 determines the closing speed of the nozzle needle 360 ,

This indirect control of the nozzle needle 360 A hydraulic booster system is used because of the rapid opening of the nozzle needle 360 required forces can not be generated with the solenoid valve. The time required in addition to the injected amount of fuel control passes through throttles of the control room in the fuel return 310 ,

The magnetic coil 320 is through the control unit 20 via control line 205 . 210 driven. As in 3 shown, the solenoid valve injector on a two-piece anchor group on. The actual magnet armature 330 and an anchor plate 331 are decoupled. The anchor plate 331 is on the magnet armature 330 guided. On the magnet armature 330 the spring force of the valve spring acts 322 , On the anchor plate 331 On the other hand, the spring force of an overstroke spring acts 332 , The magnet armature 330 is form-fitting by a sickle disk 333 to the anchor plate 331 coupled. This results in the closing force as the difference of the valve spring 322 generated force F1 and that of the over-travel spring 332 generated force F2: Closing force = F1 - F2, the against the in the valve control room 350 adjacent rail pressure the valve ball 340 press in the valve seat. When opening, that is when energizing the solenoid 320 the magnetic force acts on the anchor plate 331 , which in the direction of the magnetic coil 320 is pulled. When closing, that is, when the solenoid 320 is de-energized, the armature becomes 330 pressed down again by the spring force, the anchor plate 331 is now moved by the positive engagement in the same direction. Meets the valve ball 340 on the seat, that is, the armature stroke is zero, decoupled the mass of the anchor plate 331 from the mass of the magnet armature 330 and moves by the inertia further down, that is in the direction of the nozzle needle 360 , Thus, among other things, too much rebounding of the valve ball 340 and thus the magnet armature 330 prevented. In addition, the closing force is on the magnet armature 330 acts, magnified, because the force of the overstroke spring 332 no longer on the magnet armature 330 acts because of the positive locking anchor plate 331 to magnet armature 330 exists only in the opening direction. The anchor plate 331 is by the overtravel spring 332 returned to its original position. The anchor plate 331 has a distance from the armature guide 335 on, which is referred to as ÜH overtravel, it is about 20 ± 10 microns. The overtravel ÜH can be controlled by a selected group of several sickle discs 333 (not shown).

In modern diesel engines, the time between two injections should now be very short, preferably zero. A follow-up injection can only be triggered on such a solenoid valve injector when the armature plate 331 is back in a defined starting position. To shorten the time of swinging the anchor plate (see 4a ), the path of the anchor plate is limited by a so-called over-stroke stop.

In 4 is the hub 410 of the magnet armature 330 from the anchor plate 331 represented over time, with in 4a the overtravel 420 the anchor plate without overstroke stop and in 4b the overtravel 420 the anchor plate are shown with overstroke. Like a comparison of 4a with the 4b shows is the amount of overstroke 420 without overstroke stop for a much larger than with overstroke stop. On the other hand, the overhaul swings 420 beyond that, too. In contrast, the overstroke 420 limited to a smaller defined value by an overstroke stop.

The basic idea of the invention is, now, the main influencing parameters of the solenoid valve lift 410 and overstroke 420 . 430 in the facility 22 of the injector 18 to store and in the amount of correction of the second injection, which is usually a main injection, by the engine control unit 20 to take into account. The overstroke stop defines a lower and / or upper tolerance limit of the overstroke. In this way, the quantity value calculated for the main injection is corrected as a function of the applied spray distance and the parameters set on the injector.

Claims (4)

A method for correcting the injection behavior of at least one solenoid valve injector by storing information about the at least one injector, which were determined by comparing target values with actual values at individually multiple test points of the at least one injector, and are related and controlling the at least one injector taking into account the stored information, characterized in that is used as information of the stroke of the solenoid valve. Method according to claim 1, characterized in that that as Information a lower and / or upper tolerance limit of an overstroke be used. Method according to claim 1 or 2, characterized that on the base of the information, a correction amount of the injection valve is determined. Method according to claim 3, characterized that the Correction amount in an immediately following to a pilot injection Main injection considered becomes.