EP2126336B1 - Test device and method for checking injection components - Google Patents

Abstract

The invention relates to a test device for checking injection components, comprising a control unit, a pressure generating unit (10, 110, 210) selected by the control unit (50, 150, 25), and a test specimen holding unit (40, 140, 240, 340), which is equipped for connecting a test specimen and connected to the pressure generating unit, wherein the controller selects the pressure generating unit such that the pressure generating unit on the test specimen holding unit provides different, selectable pressure curves for the test specimen that can be connected. The invention further relates to a method for checking injection components, comprising the following steps: generating a first pressure curve by means of a pressure generating unit; adjusting the pressure generating unit to a second pressure curve, which differs from the first pressure curve; and generating a second pressure curve by means of the pressure generating unit, wherein the adjusting of the pressure generating unit comprises the adjusting of a selection of the pressure generating unit without performing physical adjustments on the pressure generating unit.

Description

State of the art

The invention is based on a test device for testing a first opening pressure of a nozzle holder combination. This is used to measure a first opening pressure of a connected nozzle holder combination to be tested. To measure the second opening pressure of the nozzle holder combination another, additional tester is used. In general, systems that include a check oil supply, a series pump, a pressure measurement, an electrical evaluation and an optional temperature control are used to test nozzle holder combinations.

In general, an injector may be used in an internal combustion engine instead of a nozzle holder combination as an injection component. For testing of injectors another tester is necessary. The system for testing injectors includes a test oil supply, a pressure generator by means of a drive and a high-pressure pump, an electrical control of the injector, a volume measuring system and a pressure and temperature control.

A test device for injectors is eg from the DE 198 51 285 known.

In order to check in a motor vehicle workshop injection components of different types, therefore, several devices are necessary. This leads to disadvantages in terms of cost and space requirements.

Disclosure of the invention

The invention enables the verification of injection components of various types with a single device. Further, the invention enables the measurement of various characteristics of an injection component type by means of a single device. In particular, the invention makes it possible to measure the first and second opening pressures of a nozzle holder combination with one and the same system. Furthermore, the invention enables the inspection of nozzle holder combinations and injectors with one and the same device. According to the invention, the same device is used for checking the pressure characteristics of a nozzle holder combination as for checking the pressure characteristic, the injection quantity and the return quantity of an injector.

The test device according to the invention comprises a pressure generating unit, which is used in a first operating mode for checking injectors and therefore builds up a time pressure curve, which corresponds to the usual operation of injectors. In addition, the same pressure generating unit is used in a second operating mode to build a pressure profile corresponding to the pressure curve of nozzle holder combinations in normal operation, wherein in the second operating mode, the pressure generating unit is driven to model the pressure profile of a series pump. In general, a pressure generating unit is used according to the invention, which can simulate the operation or certain operating states of different injection components by appropriate control, whereby the test device for many different injection components can be used.

As a pressure generating unit is in particular a common rail high-pressure pump, which is used according to the prior art only for the review of common rail injectors. According to the invention, the high pressure pump is also used to check nozzle holder combinations, wherein not the high pressure pump, but only their control is modified such that the high pressure pump simulates the behavior of a series pump.

According to another aspect of the invention, it has been recognized that the pressure generating unit of an injector test system is also suitable for testing the first and second opening pressures of a nozzle holder combination. Due to the electrical control of the pressure generating unit used for injectors, the behavior of the pressure generating unit can be changed by the control, without physical or mechanical changes to the pressure generating unit are necessary. In this way, by a suitable control of the pressure generating unit, for example, the behavior of a series pump can be simulated, which is used as a pressure generating unit in a test system for nozzle holder combinations.

According to the invention, the pressure generating unit, which is initially provided for injectors, driven so that it also simulates a behavior of pressure generating units, which simulate for checking nozzle holder combinations with a pen, nozzle holder combinations with two spring holders, stage holders, unit injectors and injectors with a magnetic coil. Alternatively, the pressure generating unit is controlled in such a way that it simulates a pressure generating unit for test systems for injectors with two magnet coils or injectors with a piezoactuator.

The invention allows the measurement of the first and second opening pressures of a nozzle holder combination. In this description, the term "first opening pressure" describes the pressure at which a first preliminary stroke is achieved in which a small outlet cross-section is released. In other words, at the first opening pressure, a point is reached where minimal fuel flow through the nozzle holder combination occurs. If the pressure is further increased, the second opening pressure is reached. This marks the exceeding of a pressure, from which the stroke of a nozzle needle increases and thus releases a larger cross-section. The second opening pressure can therefore be detected by a flattening of the pressure increase, which is generated by the increasing flow area. From reaching the first opening pressure thus a low flow rate can be determined, and after reaching the opening pressure, an increasing and higher flow rate can be determined. By a suitable control of the high pressure pump so all relevant pressure values can be generated and it can be a Characteristic can be generated by simultaneously measured and recorded the flow rate.

When measuring the behavior of injectors, these are activated to deliver test oil intermittently. Such a pulsed volume flow can be determined by means of a suitable integrating volume flow meter which has a very low measuring inertia in order to be able to follow the rapidly increasing and decreasing pressure and flow rate flanks. Alternatively, the pulsed volume flow can be smoothed by using a flexible hydraulic volume. Such a volume may be created in which the volume-enclosing surface has a diaphragm which is spring-supported. In this case, the springs can absorb and compensate for the fast pressure flanks. Preferably, the volume flow is directed by such a flexible hydraulic volume, and then by a throttle, which leads to a further smoothing, in particular in connection with the hydraulic volume. The throttle may be provided by a thin thin-walled tube extending in the form of a cooling coil, which is preferably arranged in a temperature-controlled test oil tank. In this case, a volumetric flow meter is connected to the throttle, whereby slower measuring devices can also be used by the smoothed volumetric flow, for example a gear flow meter. The spring force on the membrane is preferably applied to the membrane surface facing away from the hydraulic volume by means of a pressure plate. On this side, a channel or another volume can be provided which is connected to the environment or to a pressurized volume for pressure equalization directly or via a throttle.

According to a further aspect of the invention, the test device according to the invention comprises a control unit and a measuring device which measures the pressure and the flow rate to or through the injection component to be tested. Preferably, the measuring device comprises a pressure sensor. In the measuring device according to the invention, this measuring device is used not only for checking injectors but also of injection nozzles, for example nozzle holder combinations, stage holders and the like. Preferably, the controller is arranged to control the injection components of various types according to their respective type such that the normal operation, a certain usual operating point or a Critical operating point is driven in each case depending on the type of injection component. At the same time, the control unit preferably controls the pressure generating unit such that the corresponding operating state is present at the injection component to be checked. Furthermore, a heating means may also be provided in order to achieve the corresponding operating state with respect to the temperature. According to a further aspect of the invention, the measuring device is also flexible with regard to the injection component type to be checked and further preferably measures the pressure and the flow rate of the pressure generating unit or these and other physical variables at the outlet of the injection component to be checked or on the test piece mounting unit.

According to a further aspect of the invention, the test device comprises an evaluation unit, which is preferably connected to the control unit and / or to the measuring device and evaluates the measured values according to the set physical quantities with an evaluation method that depends on the type of injection pump. Since an operating state is provided for the injection component, which corresponds to the usual test system used for this type, the evaluation method can be carried out by type-specific test devices, and the methods can be combined in one device.

According to one embodiment of the invention, the control takes place via a measuring and control circuit board. Furthermore, the acquired data, for example, the data of the control unit, the pressure generating unit and / or the measuring device are transmitted to a central control unit and evaluated there. Preferably, the central control unit comprises a control PC with corresponding software. In one embodiment of the invention, the control PC and the software running therein assume the control of the pressure generating unit, the control of the injection components and the data acquisition of the measurement data originating from the measuring device, the control unit and / or the pressure generating unit. In a further embodiment of the invention, the acquired data are displayed graphically, for example the pressure profiles. According to a further embodiment of the invention, the test device comprises a common operating part. Preferably, different modes of operation are displayed for selection, and a graphical user interface is provided that is consistent for all types of inspection or injection component types. Preferably, the test device comprises a Prüfling-holding unit which is adapted to hold the injection component to be checked. Preferably, adapters or fittings are provided to connect the injection component sealed depending on the type of the test device.

Brief description of the drawings

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

• Figur 1 ein Übersichtsschaltbild einer ersten Ausführung der erfindungsgemäßen Testvorrichtung;
• Figur 2 ein Übersichtsschaltbild einer zweiten Ausführung der erfindungsgemäßen Testvorrichtung;
• Figur 3 ein Übersichtsschaltbild einer dritten Ausführung der erfindungsgemäßen Testvorrichtung; und
• Figur 4 eine technische Umsetzung der erfindungsgemäßen Testvorrichtung

Show it

• FIG. 1 an overview diagram of a first embodiment of the test device according to the invention;
• FIG. 2 an overview diagram of a second embodiment of the test device according to the invention;
• FIG. 3 an overview diagram of a third embodiment of the test device according to the invention; and
• FIG. 4 a technical implementation of the test device according to the invention

embodiments

In the FIG. 1 a common rail (CR) high-pressure pump 10 is shown, which supplies a buffer volume 20 with pressurized test oil. To the CR high pressure pump 10, a check oil tank (not shown) is connected, from which the CR high pressure pump 10 receives the oil with which the buffer volume 20 is supplied. Connected to the buffer volume is a valve or throttle 30, the flow rate of which can be controlled electrically (or mechanically or hydraulically) and, in the open operating state, supplies a test specimen holding unit 40 with the pressurized test oil. The CR high-pressure pump 10 is controlled by a control unit, so that the control unit the pressure and / or flow rate of the CR high-pressure pump 10 controls. Furthermore, the control unit controls the flow rate through the electrically controllable throttle 30. According to the invention, an input of a test object is connected to the test object mounting unit 40, wherein a measuring device is connected to an output of the test object. Preferably, the measuring device is connected to the control unit in order to enable a feedback and thus the maintenance of a certain operating interval or operating point. The sample holding unit 40 is configured to receive injection components of the same type of various sizes and injection components of various types and sizes. In the same way, the measuring device is equipped to be coupled to the DUT. The coupling of the Prüfling-mounting unit to the device under test and / or the coupling of the measuring device to the device under test can be provided via an adapter that fits different sizes and different types.

The controller may control the high pressure pump 10 so that the buffer volume has a certain pressure. At the same time, the control unit may control the throttle 30 so as to simulate the operation of an injector injection component. Similarly, the controller may control the pump 10 and the throttle 30 or only one of these components such that the operation of a series pump is simulated on the holder 40 so that a nozzle holder combination can be used as the test object. Due to the buffer volume, it is not necessary for the high-pressure pump to build up a high pressure in a very short time in order to simulate a sharp-edged pressure peak on the holder 40. Rather, a valve or throttle 30 with a relatively short reaction time is sufficient to simulate a corresponding pressure curve. The high-pressure pump 10 can therefore be designed to lower standards. According to one embodiment, a pressure relief valve is connected to the buffer volume 20, which opens from a certain pressure, wherein the threshold value is preferably electrically adjustable. In a further embodiment, the throttle 30 is designed as a controllable valve. Further, a throttle that determines an adjustable flow rate can be used in combination with a valve whose opening state can be changed quickly, preferably by means of an electrical signal.

The FIG. 2 shows a simplified test device with a high-pressure pump 110, the oil from a test oil tank (not shown) takes and under pressure to a DUT mounting unit 140 which is connected to the output of the high-pressure pump 110 supplies. The high-pressure pump 110 is connected to a control device which controls the behavior of the high-pressure pump. The high-pressure pump is designed to simulate different pressure profiles, for example, those of a series pump and that of an injector pump. To illustrate the corresponding pump properties, the high-pressure pump 110 must be able to be controlled in terms of its pressure curve over time and to have a suitable reaction time.

Alternatively, the in FIG. 2 shown high-pressure pump 110 from the components 10, 20 and 30 of the FIG. 1 consist. In this case, either the high-pressure CR pump 10 or the throttle 30 or a combination thereof is electrically driven to produce the desired pressure profile.

FIG. 3 shows an embodiment of the test device according to the invention, in which a high pressure pump 210 supplies a manifold 270 with pressurized test oil. The high pressure pump 210 preferably includes a buffer volume and a controllable throttle (both not shown), wherein the throttle and / or the pump are controlled by a controller 250 connected thereto. In the FIG. 3 illustrated embodiment includes a plurality of Prüfling-mounting units 240, which are each connected to the controllable distributor 250. The specimen mounting units 240 are designed for various injection components to be tested in terms of their dimensions and seals. Therefore, a test fixture unit may couple a particular size and / or injector component type to the controllable manifold 270.

The controllable distributor 270 is in accordance with the in FIG. 3 illustrated embodiment electrically connected to the control unit 250. The manifold connects, according to the controller 250, only a particular sample holding unit 240 to the high pressure pump 210. In an alternative embodiment, each sample holding unit comprises a pressure gauge and / or a flow meter. Alternatively, an intermediate piece may be provided, which measures the pressure and / or the flow, and which connects the corresponding Prüfling-holding unit with the DUT. Furthermore, a flow meter can be connected to the manifold after the manifold and to the DUT.

The controller 250 is preferably connected to a database 260 that stores data that maps the pressure history. Preferably, in the database 260, time histories and / or characteristic curves for a plurality of injection components of the same type of different size and of the same type or for different types are stored. According to the selection of the injection component type, the controller 250 loads the corresponding characteristic and / or the corresponding pressure waveform into the controller to execute pressure control corresponding to the data. Preferably, the controller 250 includes a safety device that receives measurement data from measuring devices or operating data from the high pressure pump, from a controllable restrictor, and / or from the controllable manifold 270, and at critical values or critical value combinations, drives the high pressure pump to stop generating pressure. The database can be stored in a part of an electronic memory which stores further parameters, measured values, control values and / or programs for activation, evaluation and user guidance. The electronic memory can be provided as a main memory and / or long-term memory for a central processing unit and connected to it.

The FIG. 4 shows a technical implementation of the test device according to the invention. This has an electronic display 310 and a user control panel 320. A test oil tank 330 is passively cooled by means of cooling fins. A mounting device 340 allows the clamping of an injection component to be checked. These are connected to a corresponding supply line 350 to be pressurized with test oil under pressure. The holder 340 also has a collecting container and a pressure and volume rate measuring device, which are arranged at the exit of the test specimens.

According to the invention, the control unit is connected to a display and an input, wherein the display represents the values and / or different operating modes to be selected and the input unit permits the selection of specific displays or the selection of particular operating modes. Preferably, database, control, display and selection are implemented as a PC with appropriate input / output devices. In this embodiment, a mere change of the software or control of software components allows the modification of the test device for different injection components.

The essence of the invention is to produce the oil pressure by means of a pump device with which different pressure profiles can be generated. In particular, common rail high-pressure pumps allow such flexible handling. Thus, the pump apparatus can be used not only for a common rail type injector of the type to be checked, but also for nozzle holder combinations by changing the driving accordingly. At the same time, a common rail measuring device that measures pressure, flow rate, injection and recirculation allow corresponding measurements to be taken for the characteristics of non-same-type injection components, i. H. For example, nozzle holder combinations with one or two spring holders, stage holders, unit injector nozzles and injectors with electrical control. Preferably, the controller is already designed for driving injectors, so that a typgemäßer operation of active injection elements can be performed on the test device.

Furthermore, the test device preferably comprises measuring devices for automatically checking the combination density and the pitting behavior. The seat tightness and spray pattern may be evaluated by the operator, with the test apparatus enabling a suitable type-specific operating point of the injection component to be controlled. Preferably, elements for operation and operator guidance and a display are provided immediately adjacent to the specimen mounting unit (40, 140, 240, 340).

If the high-pressure pump includes a buffer volume or if the high-pressure pump is equipped with a buffer volume, the high-pressure pump can build up a buffer of the pressurized oil, which can be quickly and quickly retrieved without having to quickly change the pressure build-up of the pump. Preferably, the buffer volume is adapted to correspond to the volume that corresponds to a common rail injector pump to map the pressure profile of a common rail high pressure pump type, if a common rail injector to be checked as injection component.

Claims (9)

1. Test device for checking injection components, comprising:

   a control unit (150, 250) ;

   a pressure generation unit (10, 110, 210) which is actuated by the control unit (150, 250), and

   a test-object holding unit (40, 140, 240, 340) which is set up for fastening a test object and is connected to the pressure generation unit (10, 110, 210), the control unit (150, 250) actuating the pressure generation unit (10, 110, 210) in such a way that the pressure generation unit (10, 110, 210) provides different, selectable pressure profiles for the test object which can be fastened on the test-object holding unit (40, 140, 240, 340), characterized in that the different, selectable pressure profiles comprise the pressure profile of a common rail high-pressure pump and the pressure profile of an in-line pump.
2. Test device according to Claim 1, the pressure generation unit (10, 110, 210) comprising a high-pressure pump and a throttle (30) which is connected to it and the throughflow rate of which can be controlled by means of the control unit (150, 250).
3. Test device according to Claim 2, the high-pressure pump being a common rail high-pressure pump which comprises a buffer volume (20).
4. Test device according to one of the preceding claims, a selection between the different, selectable pressure profiles being carried out by means of a selection device which is connected to the control unit (150, 250).
5. Test device according to one of the preceding claims, which test device comprises a measuring device which is connected to the control unit (150, 250), is in fluid communication with the test-object holding unit (40, 140, 240, 340) and the pressure generation unit (10, 110, 210), and which is set up for measuring at least one physical variable on the test object, selected from the set: mass, throughflow speed, throughflow volumetric rate, throughflow mass rate, pressure, temperature, current and voltage.
6. Test device according to Claim 5, the physical variable comprising the pressure, the throughflow volumetric rate and the mass, and the measuring device being set up for measuring the first and second opening pressures if the test object is a nozzle-holder combination, and the measuring device being set up, furthermore, to measure a discharge quantity and a return quantity at associated pressures if the text object is an injector.
7. Test device according to one of the preceding claims, the control unit (150, 250) comprising a memory (260), in which at least two actuating characteristics are stored which correspond to the respective temporal profile of at least two corresponding different, selectable pressure profiles, on the basis of which the control unit (150, 250) generates electric signals for actuating the pressure generation unit (10, 110, 210).
8. Method for checking injection components, having the following steps:

   generation of a first pressure profile by means of a pressure generation unit (10, 110, 210);

   setting of the pressure generation unit (10, 110, 210) to a second pressure profile which differs from the first pressure profile; and

   generation of a second pressure profile by means of the pressure generation unit (10, 110, 210), the setting of the pressure generation unit (10, 110, 210) comprising the setting of an actuation of the pressure generation unit (10, 110, 210), without performing physical changes on the pressure generation unit (10, 110, 210),

   characterized by an actuation of a common rail high-pressure pump according to the first or according to the second pressure profile, the first and the second pressure profiles being pressure profiles which simulate the behaviour of an in-line pump.
9. Method according to Claim 8 or 9, which method comprises, furthermore, the step:

   measuring of a pressure, a throughflow rate, an injection quantity or a return quantity,

   evaluation of the pressure, the throughflow rate, the injection quantity or the return quantity with regard to the compliance with one or more standard values according to an evaluating operation which corresponds to the checking of injection components by means of an in-line pump.

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