CN117469065A

CN117469065A - Method for diagnosing a valve

Info

Publication number: CN117469065A
Application number: CN202310931249.3A
Authority: CN
Inventors: S·布切勒
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2022-07-27
Filing date: 2023-07-27
Publication date: 2024-01-30
Also published as: DE102022207728A1

Abstract

The invention relates to a method for diagnosing a valve, in particular a valve of an injector, wherein the valve is arranged between an actuator and a chamber, in which a fluid is present, and between the actuator and the valve a further fluid is present in a further chamber, and the chamber is at least indirectly connected to a sensor element, wherein in one operating state the fluid is introduced into the further chamber by a valve opening in accordance with a specification and from there into the actuator, and in another operating state the actuator acts on the further fluid between the actuator and the valve in a manner that alters the further fluid, wherein the sensor element as part of a sensor is able to detect an effect on the fluid at least after the actuator acts on the further fluid.

Description

Method for diagnosing a valve

Technical Field

The invention relates to a method for diagnosing a valve, in particular a valve of an injector. The invention further relates to a computer program, a machine-readable storage medium and a controller.

Background

The combustion engines or internal combustion engines should be operated with less and less carbon dioxide emissions, so that the consumption of these internal combustion engines is continuously further optimized. In the context of such optimization processes, so-called "miniaturisation concepts" are increasingly being pursued in the development of internal combustion engines. This means that the so-called boost power of the combustion engine increases, i.e. the power which can be output by the combustion engine per litre of displacement increases continuously further. Furthermore, these internal combustion engines are increasingly being operated in a supercharging mode, in particular with the aid of turbochargers. In an internal combustion engine optimized in this way, combustion conditions in which the combustion process tends to knock occur in the combustion chamber, especially at high-load operating points. In addition, particularly high exhaust gas temperatures can occur in this case, so that these internal combustion engines ultimately do not run at the optimum operating point in terms of consumption.

A well-known measure for reducing the tendency to knocking is to "retard" the actually optimal ignition timing. If the combustion process at the operating point with a specific rotational speed and a specific power (torque) triggered by ignition at a specific time is compared with the combustion process at the operating point at the same rotational speed at which the same specific power (torque) should be output triggered by ignition at a later time, it can be determined that the fuel consumption of the internal combustion engine will rise for the later ignition time with the same acquired power. In order to reduce the exhaust gas temperature, which is necessary for example to protect a catalyst located in the exhaust gas plant from damaging temperatures, a so-called mixture rich will be performed. This means that λ, which is a measure of the ratio of air and fuel, is set to a value smaller than 1. This results in additional consumption in the case of a rich mixture compared to an internal combustion engine which produces the same power at the optimum operating point.

As another possible technical measure for reducing the knocking tendency (klopf neighbor) and reducing the exhaust gas temperature, it is prescribed to reduce the combustion temperature in the combustion chamber by directly injecting water into the combustion chamber or the intake passage of the engine.

Such a device for spraying water into the combustion chamber of an internal combustion engine is known, for example, from german patent application publication DE 10 2019 202 392 A1.

From publication DE 10 2016 200 694 A1 a chamber for draining off water is known. For this purpose, the direction of delivery of the pump is reversed, the ejector (valve) is opened, and thereby water is delivered from the water-carrying part back into the container. If the water injection system is emptied, i.e. filled with air, after the vehicle is parked, the refilling of the system takes place after the internal combustion engine has been started. Here, the pump and the hydraulic system (lines, high-pressure reservoirs (rails) and corresponding ejectors) must be filled with water, and the air contained in the system must be discharged or blown out through the ejectors. In this case, the contained air must be removed as completely as possible before the active water spray starts, because the entrained air may lead to an undesirable reduction in the water supply, because in some cases, during the opening of the injector or valve, not only water but also air is discharged during the opening time of the injector. In such systems for introducing water into an internal combustion engine or combustion chamber, although methods for evacuating and refilling water injection systems are known, there are problems such as the possibility of water droplets remaining in the injectors. At the corresponding external temperature or temperature surrounding the injector, such water droplets may cause water droplets remaining in the injector to become ice and may damage the injector at such a location. For example, the tubular section of the injector in which the valve closure is guided may crack (break) due to water droplets remaining there, so that the valve of the injector can no longer be closed normally. Such permanent "secondary openings" of the injector may lead to a large amount of leakage, so that water can flow uncontrolled from the pressure reservoir (water rail) via the injector (valve) into the inlet pipe. If the water system is refilled in this state, it will be possible in this case for the leakage volume flow flowing into the inlet pipe per minute through a single injector to reach one liter of water. A disadvantage of this measure is that, for example, up to the point of filling or refilling of the water system, there is no information about whether the water-carrying system is in a normal state or not, and thus whether there is a possible injector leak. Since no such fault detection has been given, such a filling process may even lead to destruction of the internal combustion engine (water impact). However, by confirming that the minimum system pressure is reached during this filling process to perform an apparent plausibility check on the tightness of the water jet system, it is still not sufficient to identify in time a severe leak of the injector, so that appropriate countermeasures, such as shutting down the water jet system, switching off the pump, can also be taken.

A method for observing the pressure in a pressure chamber during a period of time when the pump is shut down by means of a pressure sensor is known from publication DE 10 2018 205 204 551A1. The pressure profile over time determines whether the sprinkler system is sealed or leaking.

Disclosure of Invention

The method according to the invention is used for diagnosing a valve, in particular a valve of an injector, wherein the valve is arranged between an actuator and a chamber in which a fluid is present and which is arranged between the actuator and the valve or between the actuator and the valve and which is at least indirectly in connection with a sensor element and the sensor element acts on the other fluid between the actuator and the valve in such a way that the other fluid is changed, wherein the sensor element being part of the sensor is able to detect the effect on the fluid at least after the actuator acts on the other fluid, which method has the advantage that it is known whether the other fluid between the actuator and the valve and the fluid in the chamber can communicate through the valve. If it is possible to communicate, i.e. the sensor element as part of the sensor detects the effect produced by the actuator, this indicates that the valve may have an unusual opening. Such an irregular opening may be, for example, an opening that occurs in a part of the valve, for example, in that the mentioned icing occurs in the valve body against which the valve element or valve closure seals the valve. The unusual opening in the valve may also be caused by the introduction of foreign matter between the valve closure member and the corresponding counterpart, which foreign matter makes it impossible to normally close the valve opening by the valve closure member and thereby possibly communicate another fluid between the valve and the actuator with a fluid in said one chamber via the valve. It should be mentioned here that the valve need only be adapted to enable communication between one chamber and another chamber located between the valve and the actuator. Such an arrangement may be used, for example, in an internal combustion engine in which the valve allows water to be supplied to the mechanism of the engine. The means of the internal combustion engine may be, for example, a so-called intake manifold. The mechanism may also be essentially a combustion chamber of a cylinder of an internal combustion engine. Depending on the design of the device to which the method is to be applied, the fluid or fluids may be gaseous fluids only, whereby the actuator acts on the gaseous fluids and the gaseous fluids are likewise arranged in the chamber. Thus, the gaseous fluid will be in communication with another gaseous fluid in the chamber through the valve. In principle, a liquid fluid may also be arranged between the valve and the actuator, which liquid fluid is in or not in communication with another liquid fluid in the chamber through the valve. In principle, it is also possible to arrange a liquid fluid between the valve and the actuator and a gaseous fluid in the chamber, so that the liquid fluid is in or out of communication with the gaseous fluid through the valve. It is thus also possible in essence to arrange a gaseous fluid between the valve and the actuator and a liquid fluid in the chamber, such that the gaseous fluid is in or out of communication with the liquid fluid through the valve. In the case of the valve being an element of an injector of an internal combustion engine, which element is suitable or provided for injecting water, for example, the fluid on both sides of the valve may be air in the as yet unfilled state of the volume.

The mentioned actuator is essentially a driving element adapted to influence the further fluid between the valve and the actuator in such a way that the further fluid is changed. The actuator may be in a general form a gas driven element or a liquid driven element, such as an impeller machine, for example a fan, or a hydraulic driven element, such as a screw or a piston. In the case of executing the method in an internal combustion engine, the actuator may also be, for example, a piston in a cylinder of the internal combustion engine. The actuator is for example an actuator arranged outside the injector or the valve. A chamber which is at least indirectly connected to the mentioned sensor element is for example a cavity which is part of a so-called water rail, which cavity may alternatively also be referred to as a high-pressure reservoir or a pressurized reservoir or a water reservoir.

As already mentioned, another fluid located or arranged between the actuator and the valve may be arranged in the general chamber. In combustion engines, for example, the chamber may be a so-called intake pipe. The mentioned sensor element may for example be a part of the surface of the chamber facing the fluid in the chamber. For this purpose, for example, a pin can protrude through the opening into the housing, said pin being acted upon as a sensor element in the housing, for example by pressure. The sensor element may also rest against the outside of the chamber sleeve and thus, for example, indirectly detect changes in the chamber, which represent the effect of the actuator on the fluid in the chamber. The actuator acts on the fluid such that the fluid changes. The fluid can be compressed or depressurized, for example, to change its density. Here, one or more pressure waves may pass through the fluid, so that the density varies with time along the path under investigation. The manner in which the fluid is changed may also be achieved by simply compressing or simply releasing the actuator. In the case of a method implemented on an internal combustion engine, it is provided that if the actuator is a moving piston in a cylinder, a so-called inlet valve between the combustion chamber and the inlet line must be at least partially opened. The sensor element should be able to detect the effect on said one fluid at least after the effect of the actuator on said another fluid. Thus, the sensor element has previously and theoretically been able to detect the effect on the fluid in the chamber as well. Since the sensor element should be able to perform the detection at least after the action, it is provided in particular that the detection can also be performed, for example, during the action and before the action. It is also possible that the action of the actuator has ended, but that the legacy action still acts in one fluid in the chamber, or in another fluid between the valve and the actuator, i.e. for example to detect an attenuated wave in one or more fluids.

Thus, the effect on the fluid acting in the chamber can essentially be detected by the method, provided that the valve is capable of allowing fluid communication with the actuator and the valve, in particular if the valve has an unusual opening, i.e. a leak. However, it can also be determined by the method that the sensor element is able to detect an effect on the fluid after the actuator has acted, but is unable to detect a change in the fluid in the chamber, since the fluid does not undergo any change. In the latter case, this means that the valve has no unusual openings, i.e. no leaks.

Accordingly, according to another aspect of the invention, the effect of the actuator on the further fluid arranged between the valve and the actuator may be transferred to the one fluid by the valve and thus act on the one fluid. The transmission of the action through the valve may here comprise, for example, transmitting the action in a sealing gap of the valve, or, for example, enabling communication through the valve by means of another unsealing property, such as, for example, a crack in the valve element or an unconventional passage. The action of the actuator on the fluid in the chamber may depend, for example, on the pressure ratio, the fluid inflow into the chamber or the fluid outflow. The effect of the actuator may also be the pressure variation already mentioned.

According to another gist of the present invention, the action exerted on the fluid should act on the sensor element. The sensor element should receive this effect. The effect here can be, for example, a pressure increase or a pressure decrease on a sensor element, which is then configured as a pressure sensor element. In general, the effect can also be a temperature increase or a temperature decrease on a sensor element, which is then configured as a temperature sensor element.

According to a further embodiment, the sensor element transmits a signal to the receiving unit and derives an opening in the valve from the signal. According to another gist of the invention, a different pressure change caused by the actuator may be determined in the chamber between the valve and the actuator, after which the pressure change in the chamber is for example correlated with the pressure change caused by the actuator and/or the pressure change caused by the actuator is correlated with the same pressure change in the chamber and/or the pressure change in the chamber caused by the actuator causes a pressure change with a smaller amplitude and/or the pressure change between the valve and the actuator is correlated with the pressure change in the chamber such that it has a pressure offset compared to the pressure change between the valve and the actuator. The pressure deviations mentioned are in particular pressure deviations over time. Alternatively or additionally, it may be a pressure offset in terms of the magnitude of the pressure. An advantage of identifying the corresponding pressure change in the chamber is that the type of unconventional opening in the valve can or may not be inferred from the type of pressure change.

If the pressure changes are the same, it can be inferred here, for example, that there is a relatively large opening in the valve. A relatively large opening may be created because the closure member of the valve is not closed because of objects, such as debris or other dirt, deposited between the counterpart and the closure member. If the pressure change in the chamber is a pressure change of a smaller magnitude than the pressure change directly caused by the actuator, this may for example show that there is only a very small, non-conventional opening in the valve, which causes a smaller magnitude with a certain damping by the effect of the overflow.

The time-type pressure excursion may be due to the damping effect created by the overflow through the opening (intermediate case between very large opening and no opening). The absolute value of the sensor, e.g. the pressure value, is shifted up or down, possibly due to drift of the (pressure) sensor.

According to another gist of the invention, the pressure change caused by the actuator between the valve and the actuator may be related to a pressure change in the chamber, which pressure change in the chamber delays to occur and/or results in a smooth pressure drop in the chamber.

According to another gist of the invention, a pressure change is induced in the chamber, the frequency of which is different from the frequency of the pressure change between the valve and the actuator. This change in frequency may occur through the possible superposition of pressure waves generated during flooding due to reflections or periodically formed and detached turbulence. This occurs even for a plurality of unsealed valves. This has the advantage that the algorithm used for identifying the leak will be more robust when looking at this characteristic.

According to a further feature of the invention, it is provided in the context of the method that the pressure change caused by the actuator in the chamber between the valve and the actuator forms a pressure curve which changes with a delay, smoothly, with a smaller amplitude and with a pressure offset.

According to another gist of the method, the sensor element determines no effect or no effect detectable on the fluid because the valve is sealed. The detection of this state results in a positive state of the valve being determined, since the valve operates in a manner that corresponds to a valve that is technically normal. According to another gist of the invention, provision is made according to the method for the difference between the pressure characteristic in the chamber and the pressure characteristic between the valve and the actuator to be compared with a threshold value. This has the advantage that a deviation or difference between the pressure characteristic in the chamber and the pressure characteristic between the valve and the actuator can be evaluated in terms of magnitude. If, for example, the pressure characteristic between the valve and the actuator has a certain magnitude, it can be determined, for example, by means of a threshold value, whether the difference from the pressure characteristic in the chamber is sufficiently small (in the sense of "not less than") in order to infer a valve damage or infer an unconventional opening state of the valve. The valve may also allow for instance the pressure characteristics in the chamber to be slightly influenced by the actuator due to wear. According to a further gist of the invention, it is provided that a so-called pressure offset of the sensor element is taken into account. The pressure shift corresponds to the "pressure deficiency high" acquired, i.e. the pressure difference, which for technical reasons causes the acquired pressure to appear to be higher than the actual pressure by the pressure shift. For example, if an actuation of the actuator results in a pressure reduction between the valve and the actuator which, although at least partly transferred to the chamber, takes into account the mentioned pressure offset when taking the pressure in the chamber, the pressure difference between the chamber and the position between the actuator and the valve eventually results in an excessively high pressure difference. Thus, disregarding the pressure offset will result in a possible error in the evaluation of the valve, as a valve that is not actually sealed may be identified as being sealed. The just mentioned pressure offset can advantageously be obtained if the pressure in the chamber and the pressure between the valve and the actuator are obtained before the actuator is applied. If it is provided by the technical means that, as specified, an ambient pressure prevails in the chamber before the actuation of the actuator and that an ambient pressure should likewise prevail between the valve and the actuator, the magnitude of the error in determining the chamber pressure, in particular the pressure offset mentioned, can be determined, in particular, if the pressure between the valve and the actuator is properly determined. The value of the pressure offset is preferably obtained from these two pressures.

According to a further embodiment of the invention, a time integral of the difference between the pressure in the chamber and the pressure between the valve and the actuator is obtained. This has the advantage that the pressures can be observed over a longer time interval and thus the time delay of the physical reaction to the pressure in the chamber can also be taken into account by integration.

According to a further embodiment of the method, a time profile of the action of the actuator on the chamber between the actuator and the valve and a time profile of the action of the actuator on the chamber are acquired, and a correlation of these time profiles is deduced from the acquired characteristics. The advantage of this measure is that one or more dynamics formed in the time curve are thereby made available for comparing the two pressure curves in order to obtain a possible correlation. Very particularly, it is provided that the degree of correlation of the time profile is acquired by means of machine learning. This enables the effect of the actuator on the chamber on the valve side to be identified, which is not straightforward. If such an influence is recognized, for example, an unambiguous analysis value can be output, which indicates, for example, the presence or absence of an influence, so that a "unsealed" or "sealed" can be determined.

Furthermore, a computer program is proposed for performing all the steps of one of the above-mentioned methods or programmed such that a method according to one of the proposed methods is performed when the computer program is run on a computer. Furthermore, a machine-readable storage medium is proposed, on which the computer program mentioned is stored or on which a computer program for use in the aforementioned method is stored. A controller is furthermore proposed, which is adapted to perform all steps of the aforementioned methods or is programmed to be applied in one of the aforementioned methods.

Drawings

Embodiments of the invention are illustrated in the accompanying drawings and are set forth in more detail in the description that follows. Wherein:

fig. 1 shows a first embodiment of an apparatus on which the method according to the invention is to be performed;

FIG. 2 illustrates a method;

fig. 3 shows a second embodiment of an apparatus on which the method according to the invention is to be performed;

FIG. 4 shows a schematic representation of a motor vehicle with an internal combustion engine and a carrier system or water-carrying system;

fig. 5 schematically shows an internal combustion engine;

FIG. 6 shows signal curves or pressure curves for a carrier fluid system or a valve of a carrier water system as a function of time according to different conditions;

fig. 7 to 17 show different examples of pressure curves;

FIGS. 18-24 illustrate different diagnostic examples based on examples of pressure curves; and

fig. 25 shows an example of a neural network.

Detailed Description

Fig. 1 shows a first embodiment of a device 1 on which the method according to the invention is performed. The device 1 has a valve 2 between a further chamber 3 and a chamber 4. The further chamber 3 is located between the valve 2 and the actuator 5. Said chamber 4 is located between the valve 2 and the sensor element 6. The device 1 shown schematically here may be, for example, part of an internal combustion engine not shown here. The device 1 shown in fig. 1 can be in various operating states. The valve 2 shown can be opened, for example, as specified, and can likewise be closed as specified. If the valve 2 is opened as prescribed, the further chamber 3 and the one chamber 4 may communicate with each other, so that, for example, a further fluid 7 located in the further chamber 3 may be delivered to a fluid 8 in the one chamber 4. This transport is likewise possible in the other direction by opening the valve 2 according to the regulations: the fluid 8 may be fed to the further fluid 7 in the further chamber 3 or penetrate there through an open valve. The device shown here can, for example, introduce the one fluid 8 at least partially into the other chamber 3 with the valve 2 open after filling the one chamber 4 with the one fluid 8 via an inlet line not shown here. Provision is then made, for example, for the further fluid 7 and the fluid 8 to be led from the further chamber 3 towards the actuator 5 or into the actuator.

The valve 2 mentioned here can be opened and closed normally, since it is opened or closed on the basis of a predefined actuation of the valve 2. The third, non-conventional, i.e. unexpected, operating state of the valve 2 may be caused, for example, by the presence of, for example, foreign bodies, such as fragments resulting from the manufacture of parts connected to the system or parts of the system, between the sealing contours of the valve 2, not shown here. However, the valve 2 may not be normally closed due to another foreign matter such as "dirt", so that the valve leaks. Another abnormal state of the valve may occur, for example, by the fluid 8 solidifying, for example, due to a low ambient temperature, exerting an unacceptably high force in the valve, for example, due to expansion, and thereby causing damage to the valve 2, for example. Such damage may be caused, for example, by cracks.

The state of the valve 2 can be diagnosed by the method described below and shown in fig. 2. The actuator 5 acts here on the further fluid 7 between the actuator 5 and the valve 2 in step S1, so that the further fluid 7 changes. The further fluid 7 is here changed, for example, in terms of its density, i.e. the further fluid 7 is compressed or relieved, for example. The actuator 5 is in this case designed as a general drive element, for example as a piston machine or a fan. As a driving element of this kind, the actuator 5 may for example generate a pressure wave in the further fluid 7, which pressure wave travels through the further chamber 3 and, depending on the state of the valve 2 (open, closed, unsealed, i.e. leaking), causes the driven further fluid 7 not to flow through or past the valve 2 (closed) and thus not to influence the fluid 8. In the first-mentioned case (valve 2 open), the sensor element 6, as part of a sensor not fully shown here, can detect the effect on the fluid 8 at least after the effect of the actuator 5 on the further fluid 7 (step S2). If the sensor element 6 is part of, for example, a pressure sensor, the sensor element 6 is able to detect the pressure effect on the fluid 8. If the valve 2 is closed in the course of performing the method, the sensor element 6 cannot detect the effect of the actuator 5 on the further fluid 7, since no effect is transferred to the one fluid 8 (no communication between the chambers 3, 4). If the valve 2 transmits an action to said fluid 8, it is provided that the action affects the sensor element 6 and is received or perceived accordingly. The sensor element 6 then preferably transmits a signal to the receiving unit 9. The opening in the valve 2 can then be deduced from this signal (step S3). In addition to this, the signal is particularly preferably an electrical signal which is processed and/or analyzed in the receiving unit 9 or in another unit, for example a controller.

Fig. 3 shows a second embodiment of a device 1 on which the method according to the invention is to be performed. The device 1 according to fig. 3 differs from the device 1 according to fig. 1 in that a further valve 10 is arranged between the further chamber 3 and the actuator. Although in the device 1 according to fig. 1 the actuator 5 may be identical to that in the device 1 according to fig. 3, in fig. 3 the actuator 5 is actually exemplarily designed as a piston machine with a piston 11. The valve 10 can be opened or closed in this case. In order to determine the effect on the fluid 8 in the chamber 4, the actuator 5, here with its piston 11, acts on the further fluid 7 through the open valve 10, so that the further fluid changes, when the device 1, here the valve 2, is diagnosed. As already described for the embodiment according to fig. 1, the action of the actuator 5 is then transferred (valve 2 open or leaking) by means of the further fluid 7 or not (valve 2 closed) to the fluid 8.

Fig. 4 shows a schematic illustration of a motor vehicle 12 with an internal combustion engine 13 and a fluid or water carrier system 16. The motor vehicle 12 has an internal combustion engine 13 as a drive, which is also shown here in a very schematic manner. The internal combustion engine has a device 1, which is embodied here as a water injection system. The water injection system or the device is used to influence the combustion carried out there, if necessary, in different operating situations of the internal combustion engine 13. The device 1 or the water injection system has a tank 19, which serves here as a water reservoir. The device 1 furthermore has a conveying device 22 and a device configured as a spraying device. A water pump 28, which is part of the conveying means 22, is located between the tank 19 and the apparatus 1. The water pump 28 or its delivery unit may be driven by an engine 30. In the section of the supply line 33 between the tank 19 and the water pump 28, in the tank 19, there is a filter 36 (prefilter). Between the filter 36 and the water pump 28 is a portion of a shut-off valve 39, here electrically operated. The shut-off valve 39 has two different switching positions. In the switching position shown in fig. 4, the shut-off valve 39 is in the "off" position. In a further switching position, the shut-off valve 39 serves to continuously switch on the supply line 33 ("channel open"). This enables the fluid 8 (water) to be delivered from the tank 19 to the apparatus 1 (spraying device) through the shut-off valve 39 and the water pump 28. In parallel with the line of the transfer line 33 extending between the water pump 28 and the tank 19, there is a parallel line of the transfer line 33. This line of the transfer line 33 is connected to the transfer line 33 line between the water pump 28 and the device 1 by a T-connection 40. This line of the transfer line 33 serves as an overflow in case the water pressure in the transfer line 33 has reached the target pressure. To substantially maintain this target pressure, the water pump 28 continuously pumps. However, if no water (the fluid 8) is injected into the mechanism of the internal combustion engine 13, for example by the device 1, the fluid 8 fed by the water pump 28 is fed back into the tank 19, if necessary, via the T-connection 40. The returned water or fluid 8 is here, for example, passed firstly through a so-called perforated plate 42 and then through a check valve 44 in order to finally flow back into the tank 19. The device 1 has a so-called high-pressure reservoir, which corresponds to the one chamber 4 (water rail) already mentioned with respect to fig. 1 and 3. The one chamber 4 is filled by a transfer line 33. The pressure or water pressure in the high-pressure reservoir (the one chamber 4) is monitored by a pressure measuring device (the sensor element 6). From the high-pressure reservoir (the one chamber 4), the ejector 52 and its valve 2 are supplied with fluids 7, 8 (water). For an in-line engine with a cylinder bank (four, five, six, … …) the number of valves 2 is typically equal to the number of cylinders of the internal combustion engine 13. For an engine or internal combustion engine 13 having a plurality of cylinder groups and a high pressure reservoir for each cylinder group, the number of valves 2 is typically equal to the number of cylinders of the cylinder group.

Fig. 5 schematically shows an internal combustion engine 13. In said fig. 5 a cylinder 55 is shown. The piston 11 slides in said cylinder 55. The piston 11 is articulated by means of a connecting rod 61 to a drive shaft of the internal combustion engine 13, which is not shown here. The drive shaft may be a crankshaft. The combustion chamber 65 is located above the piston 11-and thus between the piston 11 and the cylinder head 63. The cylinder head 63 has in addition to this a cylinder head which normally encloses a combustion chamber 65, but also other components, such as a so-called bonnet, for example. In this embodiment, a nozzle 68 is inserted into the cylinder head 63 (cylinder head), which in this case injects or is able to inject fuel directly into the combustion chamber 65. On the inlet side, the combustion chamber 65 is closed by means of an inlet valve 70, which in the embodiment according to fig. 3 may for example correspond to the valve 10. On the outlet side, the combustion chamber 65 is closed by means of an outlet valve 72. An inlet pipe 75 (e.g., also referred to as an intake pipe) is located upstream of the combustion chamber 65 (suctioning air), via which air is suctioned into the combustion chamber 65 when the inlet valve 70 is opened. In addition, a throttle 78 is provided in the inlet pipe 75. Also attached to the inlet pipe 75 is the already mentioned injector 52 (nozzle for water) with the mentioned valve 2. The injector 52 is oriented such that it is capable of injecting water or the further fluid 7 into an inlet pipe 75 (corresponding to the further chamber 3 according to fig. 1 and 3) during operation of the internal combustion engine 13. Depending on the design of the internal combustion engine 13, a glow plug (not shown) is also arranged in the cylinder head or cylinder head 63, which, in the case of a self-igniting engine/diesel engine, serves to reliably ignite the mixture of fuel and air in the combustion chamber 65 in the still cold state of the internal combustion engine 13. If the internal combustion engine 13 is configured as an external ignition engine (gasoline engine), a spark plug is usually attached in the cylinder head 63, by means of which the fuel-air-mixture in the combustion chamber 65 is ignited. After ignition of the fuel-air mixture, the fuel-air mixture is discharged as exhaust gas into the outlet pipe 80 through an opening opened by the outlet valve 72. The exhaust gas flows via the outlet pipe 80 into a mechanism for converting the exhaust gas, not shown here.

The already mentioned methods or method steps S1, S2 and S3 applied to the device described in fig. 1 and 3 can also be applied directly in the embodiments according to fig. 4 and 5.

Each injector 52 then has a valve 2, in the embodiment according to fig. 4 and 5 an internal combustion engine 13 is provided as actuator 5, which engine has at least one piston 58 that moves up and down, in the embodiment according to fig. 4 and 5 the chamber 4 corresponds to the high-pressure reservoir 46, in which, before filling the high-pressure reservoir 46, gas, which at least mainly consists of air, is first present as the one fluid 8 instead of water. Furthermore, in this exemplary embodiment, the further chamber 3 is designed as an inlet line 75 or an intake line, so that here too, between the actuator 5 designed as a piston 58 and the valve 2 integrated into the injector 52, there is the further fluid 7, i.e. air, which is located in the further chamber 3 designed here as an inlet line 75 or an intake line. A chamber 4, which is embodied here as a high-pressure reservoir 46, is also at least indirectly connected to the sensor element 6. At least in operative connection in such a way that the sensor element 6 can acquire the properties of the fluid in the chamber 4 or the high-pressure reservoir 46. If the internal combustion engine 13 according to the embodiment shown in fig. 4 and 5 is started, i.e. cranked, by a drive element, such as a starter (monorail starter, crankshaft starter or other drive element) in a known manner, the actuator 5, i.e. here the piston 11, performs a reciprocating movement in the cylinder 55. With the inlet valve 70 open, the actuator moves the further fluid 7 between the piston 11 and the valve 2 (here in the injector 52), so that the actuator 5 here also acts on the further fluid 7 between the actuator 5 and the valve 2 in such a way that the further fluid 7 is changed. By means of, for example, a downward movement of the piston 11, the air pressure in the combustion chamber 65 and in the further chamber 3 (inlet pipe) is reduced, so that this reduced air pressure acts in front of the valve 2 in the injector 52. If the piston 11 as an actuator moves in the direction of the top dead center, the air pressure in the combustion chamber 65 or the inlet pipe 75 increases again, so that the air pressure before the valve 2 in the injector 52 also increases again. According to the method provided herein, the sensor element 6, which is part of the sensor, is able to detect the effect on the fluid 8 in the high-pressure reservoir 46 at least after the effect of the actuator 5 (piston 11) on the further fluid 7. If the valve 2 opens due to the already mentioned fragments or other objects in the closing seam of the valve 2, the action of the actuator piston 11 on the further fluid 7 (air pressure drop, air pressure rise) is transmitted through the valve 2 to the one fluid 8 and thereby acts on the one fluid 8, i.e. increases the air pressure or decreases the air pressure. In this case, it is provided that the action, i.e. the increase or decrease in the air pressure, acts on the sensor element 6. It is provided here that the sensor element 6 transmits a signal to a receiving unit, here the receiving unit 53, and that the opening in the valve 2 is deduced from the signal.

FIG. 6 shows a signal or pressure curve p ₈ How this may vary over time from the moment tign when the ignition of the internal combustion engine is switched on (corresponding to the pressure profile p, depending on the different conditions for the valve 2 ₈₁ To p ₈₆ ). Thus, curve p ₈₁ A constant pressure rise is shown, which may be, for example, due to a temperature T4 rise in the one chamber 4. Pressure curve p ₈₂ A pressure rise with a constant slope is shown until the heat loss from the one chamber 4 (water rail, high pressure reservoir) and the waste heat supply from the combustion engine 13 reach a stable equilibrium. Pressure curve p ₈₃ Showing that the overall constant pressure is generally maintained, typically due to (simultaneously) achieving a stable equilibrium or neither heat supply nor heat dissipation. According to curve p ₈₄ For example, shows a slightly decreasing pressure profile, since for example the temperature in the one chamber 4 effectively decreases. This situation may occur when a vehicle with such an internal combustion engine 13 is driven into a cold environment after start-up or after start-up in an electric operating mode (vehicle with hybrid drive) from a somewhat warm garage and the internal combustion engine of the vehicle is subsequently switched on for driving purposes13 thereafter. By operation of the internal combustion engine 13, the temperature in the chamber 4 is raised, which explains the pressure curve p ₈₄ Rise of (3). Pressure curve p ₈₅ A non-linear course of the initially rising pressure curve is shown, i.e. the temperature rises as a result of the heating of the internal combustion engine 13, and after a certain time a steady balance of heat loss and heat supply is likewise entered. Pressure curve p ₈₆ A possible actual course of the pressure curve is also shown, wherein the vehicle initially moves from a warm parking space into a cooler environment and subsequently heats the chamber 4 by starting the internal combustion engine 13. These curves represent typical cases of a valve 2 that is technically normal.

Fig. 7 shows the pressure p in the inlet pipe 75 or the inlet pipe ₇₅ Is an example of a curve. The theoretical curve of the pressure detected by the sensor element 6 or the sensor serves to illustrate the considerations set forth below. This basic curve of the pressure is used in other embodiments to explain different and possible transfer functions.

Fig. 8 shows the pressure p in the further chamber 3 detected or measured by the pressure sensor 90 (fig. 5, inlet pipe, air inlet pipe) ₃ And the pressure p in said one chamber 4 ₄ A theoretical first transfer function therebetween. As can be seen here, the pressure difference Δp is at pressure p ₃ Or p ₄ Is constant throughout the curve of (c). The pressure difference Δp corresponds, for example, to a value of a so-called absolute amplitude offset or a so-called pressure deviation. Such different curves are due, for example, to technical differences in the sensor elements or pressure sensors. This technical difference between the sensor elements or sensors then leads to an offset of the otherwise identical pressure curve in the further chamber 3 or in the inlet pipe or inlet pipe and in the one chamber 4 or in the water rail or in the water high-pressure reservoir. Such a pressure curve or correlation of pressure curves or pressure p ₃ And p ₄ The correlation of the curves of (2) thus essentially corresponds to the conclusion that the two pressure curves are correlated with each other.

As can be clearly seen from the two pressure curves, the pressure changes Δp ₃ And Δp ₄ In this case it is the same as the case may be,so that the pressure change between the valve 2 and the actuator 5 caused by the actuator 5 is related to the same pressure change in said one chamber 4. Although the view in fig. 8 is based on the technical differences of the sensor elements and thus the pressure in the one chamber 4 is acquired higher than the pressure in the other chamber 3, the pressure can also be determined in such a way that the pressure acquired by the sensor elements in or for the one chamber 4 is lower than the pressure acquired by the sensor elements in the other chamber 3 and thus the pressure curves can be interchanged.

FIG. 9 shows the pressure p ₃ And p ₄ Another view of the theoretical curve of (a). Pressure p ₃ And p ₄ Both start from a common pressure value p, which has been generated by the stationary state of the vehicle. If the further chamber 3 is excited by the movement of the actuator 5, here in this example by a downward movement of the piston 58, the pressure p in the further chamber 3 ₃ Descending. The pressure change in the chamber 4 is delayed, as shown here, by a constant time difference Δt.

FIG. 10 shows the pressure p ₃ And p ₄ Is a further correlation of the curves of (a). Here shows the pressure p ₃ At pressure p ₄ How the amplitude decay appears in the curve of (a). This phenomenon represents a loss process when overflowing from the further chamber 3 to the one chamber 4 via the valve 2 or a leak site there. Accordingly, the amplitude of the pressure variation in the one chamber 4 is smaller than the amplitude of the pressure variation in the other chamber 3 caused by the actuator 5.

Fig. 11 shows another theoretical curve for different pressures. If the pressure p ₃ As shown here, the pressure p in the one chamber 4, for example ₄ Can be varied as in the first variant, for example as a function of the pressure p ₄₁ Shown in the graph of (2). Such a curve corresponds to a smoothing, i.e. for example to a filtering of the frequency, which is reflected for example in the pressure p ₃ Is shown in the figure). Such frequency filtering may be performed, for example, by a leak site, or may be a device1 or a plurality of unsealed valves 2 in the internal combustion engine 13. A plurality of such unsealed valves 2 or ejectors 52 representing them result in a superimposed effect in said one chamber 4. The pressure p in the second variant drawn here ₄ Is a curve p of (2) ₄₂ Without offset, as can be seen in particular at the end of the curve drawn here, while another curve p ₄₁ With an offset which in turn can be attributed to a different sensor element 6 or a differently calibrated or de-calibrated sensor element 6.

FIG. 12 shows the pressure p ₃ And p ₄ Which also start from the same initial value. As shown here, if the pressure change between the valve 2 and the actuator 5 caused by the actuator 5 is transmitted via the valve 2 to the one chamber 4 and the medium located there or the one fluid 8, a frequency reduction may occur when transmitting via the valve 2.

Fig. 13 shows a so-called identical transfer. This means that a pressure change acting by the actuator 5 in the further chamber 3 between the valve 2 and the actuator 5 causes the same pressure change or the same pressure curve in the one chamber 4 via the valve 2.

Fig. 14 shows how multiple transfer effects through one or more valves 2 are superimposed. Here it is shown how the pressure p is generated by a time delay Δt ₄ Is a curve of the movement of the curve. Furthermore, a pressure offset Δp is shown here, which can be produced, for example, by the sensor differences already mentioned. Furthermore, the pressure p is shown ₃ Is the curve and the pressure p of (2) ₄ Amplitude decay between the curves of (a). Further, fig. 13 shows the slave pressure p ₃ To the pressure p ₄ Is described, and frequency variation. In practice it can be assumed that the transfer from the further chamber 3 (inlet pipe 75 or inlet pipe) via the leak point to the one chamber 4 (high-pressure reservoir 46 or water rail) is approximately the same.

Fig. 15 shows another embodiment of a pressure curve. Here is shown the pressure p caused by the actuator ₃ Is not affected by the pressure p ₄ So that the sensor element 6 does not detect an effect on said fluid 8, because the valve 2 is normally sealed.

Possible diagnostic methods will be further discussed in the subsequent figures. Based on the different transfer functions shown in the above figures, a number of possible diagnostic methods can be derived. These diagnostic methods are described as exemplary below.

Fig. 16, for example, shows a variant of the diagnostic method, according to which, if at pressure p ₃ And p ₄ At least once at time t, an absolute pressure difference Δp greater than a predetermined absolute pressure threshold is detected, valve 2 is diagnosed as normal. Since the pressure difference Δp is greater than the mentioned threshold value Y at least once in the example shown in fig. 16, the result of the diagnosis here is that the valve 2 is normal. Furthermore, for this example, in a further variant, it may be provided that, if the method is at time t _ign After the start and after a defined time interval tdiag has elapsed, i.e. before the end of the defined time interval, the threshold Y is exceeded, the valve 2 is considered normal. Such a time interval may be, for example, 10 seconds. According to this diagnostic variant, it is provided that the pressure characteristic in the chamber 4 is matched to the pressure characteristic p between the valve 2 and the actuator 5 ₃ The difference between them is compared with a threshold Y.

The pressure offset Δp, which is plotted, for example, in fig. 8 and 14, can of course also occur in the case shown in fig. 16. A disadvantage is that in some cases, if the pressure offset Δp is too high, the unsealed valve 2 (injector 52) may be diagnosed as sealed. For example, this may occur on the basis of the pressure curve p ₃ And p ₄ As shown in the view according to fig. 17. Here, a pressure offset corresponding to a defined Δp greater than the threshold value Y is determined between the two curves and over the entire curve thereof. This will correspond to the diagnosis to be made, according to which the valve 2 is normal, corresponding to the previous example according to fig. 16. However, due to pressure p ₃ And p ₄ The curve of the synchronization of the two here, it is clear that the actuation of the other chamber 3 by the actuator 5 is transmitted to the one chamber 4 via the valve 2 and the valve 2 or the injector 52 is diagnosed as faulty accordingly.

According to FIG. 18The diagnostic embodiment provides that the pressure p in the chamber 4 is acquired before the actuator 5 is activated ₄ And the pressure p between the valve 2 and the actuator 5 ₃ And according to the two pressures p ₃ 、p ₄ The pressure offset Δp is preferably obtained. If the method is carried out on the internal combustion engine 13, the respective pressure values are acquired and stored before starting the internal combustion engine 13, and the acquired differences are then compared with one another if necessary. Thus, after the start of the method or after the start of influencing the further chamber 3 by means of the actuator 5, the currently measured pressure p should be taken on the one hand at any time ₄ And the last pressure sensor value p before the engine start or the internal combustion engine start ₄₀ Difference between them. Likewise, for the pressure in the further chamber 3, a currently measured pressure value p is acquired ₃ And the pressure sensor value p before the start of the internal combustion engine 10 ₃₀ Differences between them. Then can be based on the difference Δp= (p ₄ -p ₄₀ )-(p ₃ -p ₃₀ ) In comparison with a threshold value or threshold value Y it is determined whether the valve 2 is normal. If the value of Δp is greater than threshold Y, valve 2 should be considered normal. This diagnostic variant will advantageously be independent of the offset value of the sensor. According to the view of fig. 18, essentially the ideal situation is again shown, according to which there is no time offset between the two pressure curves. However, if there is a time offset, such a time offset may pose a problem in that the valve 2 is so sealed, since the query about the threshold Y may again be above the threshold. The unsealed valve 2 may then be erroneously declared sealed.

Fig. 19 shows another diagnostic method according to which the integrated difference value is to be obtained. The integrals are acquired over the same longer time interval between t1 and t2, respectively. This difference should be compared with the already mentioned threshold value Y in order to obtain a more reliable diagnostic criterion. Here, for example, it is provided that the integral or integral value is determined at the beginning of the influence of the actuator 5 of the further chamber 3 and is calculated at a later point in time t 2. This has the advantage that the time delay of the physical reaction can be taken into account by integration. Thus the valve 2 and the valve in said one chamber 4 will be taken upPressure p between actuators 5 ₃ 、p ₄ And then compared to a threshold.

However, as becomes clear from a comparison with the view according to fig. 20, it is again problematic here that the pressure offset Δp may lead to a difference between the two integrals (shaded areas) between t1 and t2 leading to an excessively large value which is greater than the threshold value Y, whereby the valve 2 may possibly be diagnosed as normal, but in particular the pressure curve p ₄ With pressure curve p ₃ Clearly, the comparison of (2) shows that the valve 2 is clearly diagnosed as faulty here. Furthermore, in the embodiment or diagnosis according to fig. 20, it is disadvantageous if the pressure p in the further chamber 3 (intake line) is the same as that of the other chamber ₃ The feedback on the chamber 4 becomes smaller or the integrated value itself is not decisive, but is, for example, a dynamic minimum curve, for example, a pressure p which is hardly identifiable but exists ₃ Related pressure p ₄ The minimum fluctuation of (2) is decisive, the integration method also reaches its limit. Because in this case the whole dynamics will degenerate into a single value, i.e. not resolved, nor will its complexity be assessed.

Thus, for example, according to a further embodiment of the diagnostic method, it is proposed to acquire and analyze a time profile of the action of the actuator 5 on the further chamber 3 between the actuator 5 and the valve 2 and a time profile of the action of the actuator 5 on the one chamber 4, and to infer from the acquired characteristics the degree of correlation of the time profiles of the pressures p3, p 4. Thus, for example, it is proposed according to the embodiment of fig. 21 to apply a pressure p ₃ 、p ₄ The extreme points (valley points or minima TP3, TP4; peak points or maxima HP3, HP 4) or inflection points WP31, WP41, WP32, WP42 in the curve of (a) are used for analysis. This has the advantage that a plurality of features of the dynamics (dynamics features), such as the just mentioned inflection point and extreme point, can be used for comparing the pressure p ₃ 、p ₄ To infer that a possible correlation is obtained.

According to a further embodiment for the diagnostic method, it is proposed that the leak detection of the valve 2 is performed by means of an algorithm that is associated with machine learning. For this purpose, for example, nerves can be consideredNetwork to identify pressure p ₄ Pressure p to water rail ₃ The smallest, but not simplified, representation of the effect of (c). Thus, for example, along the respective pressure curves p ₃ 、p ₄ The measured values represented by integers at a particular location will represent a so-called characteristic that is an input parameter for the neural network. In the embodiment according to fig. 22, these are, for example, for each pressure curve p ₃ 、p ₄ Twenty-three features are given. By means of the neural network, the pressure p can be detected by the tightness/leakage of the injector 52 or of the valve 2 ₃ To pressure p ₄ (water rail pressure) cannot be represented simply. A value of 1 or 0 may be given as a result, wherein a value of 1 for example represents the presence of an influence or an unsealability, or a value of 0 represents the absence of an influence and thus the tightness of the valve 2 or the injector 52.

Fig. 23 and 24 exemplarily show the pressure p ₃ The transfer effect to said one chamber 4 and thus to the pressure p ₄ The transfer effect of the size or curve of (a) can be very small. If, for example, the above-mentioned method with threshold value Y is used, it is likely that a valve 2 or injector 52 seal is inferred, despite the even very slight transfer effect from the further chamber 3 to the one chamber 4. To further improve the method it is proposed to use the feature space of the machine learning algorithm to improve the predictive capability of the neural network. Thus, for example, as shown in fig. 24, along the individual pressure curves p ₃ 、p ₄ The measured values represented by integers at specific locations are also denoted here as so-called features as input parameters for the neural network. In the embodiment according to fig. 24, these are, for example, for each pressure curve p ₃ 、p ₄ Twenty-three features are given. This can be applied for example to two pressures p in the further chamber 3 and the one chamber 4 or in the water rail and the air inlet pipe ₃ 、p ₄ The difference between them.

As shown in fig. 25, a trained neural network 80 for diagnosing leakage may be established based on the forty-six input values exemplarily shown. For example, a vector X with forty-six features can be input in the input layer L1, and the neural network can ultimately give an output of "1=unsealed" or "0=sealed" based on the forty-six input features, with the aid of two hidden layers and the use of three transfer functions in layers L2 and L3 (hidden layers), respectively. The number of layers (depth of the neural network) and the corresponding number of transfer functions, here with three weighting factors each, can be adapted in software for optimization purposes.

Claims

1. Method for diagnosing a valve (2), in particular a valve (2) of an injector (52), wherein the valve (2) is arranged between an actuator (5) and a chamber (4) in which a fluid (8) is present and between the actuator (5) and the valve (2) a further fluid (7) is present in a further chamber (3), and the chamber (4) is at least indirectly connected to a sensor element (6), wherein in one operating state the fluid (8) is introduced into the further chamber (3) by the valve (2) opening in accordance with a specification and from there into the actuator (5), and in another operating state the actuator (5) acts on the further fluid (7) between the actuator (5) and the valve (2) in such a way that the further fluid (7) is changed, wherein the sensor element (6) as a part of a sensor is able to act on the further fluid (8) at least after the actuator (5) has acted on the further fluid (7).

2. Method according to claim 1, characterized in that the action of the actuator (5) on the further fluid (7) is transmitted through the valve (2) to the fluid (8) and acts on the fluid (8).

3. A method according to claim 2, characterized in that the effect affects the sensor element (6).

4. A method according to claim 3, characterized in that the sensor element (6) transmits a signal to a receiving unit (9) and from the signal it is deduced that an opening is present in the valve (2).

5. Method according to any of the preceding claims, characterized in that the pressure change (Δp) caused by the actuator (5) between the valve (2) and the actuator (5) ₃ )：

-and the pressure variation (Δp) in said one chamber (4) ₄ ) Correlation; and/or

-the same pressure variation (Δp) as in the one chamber (4) ₄ ) Correlation; and/or

-a pressure variation (Δp) in said chamber (4) ₄ ) Is smaller than the pressure variation (Δp) caused by the actuator (5) ₃ ) Is a magnitude of (2); and/or

-a pressure variation (Δp) between the valve (2) and the actuator (5) and a pressure variation (Δp) in the chamber (4) ₄ ) In relation, the pressure change in the chamber is related to the pressure change (Δp) between the valve (2) and the actuator (5) ₃ ) With a pressure offset.

6. Method according to any of the preceding claims, characterized in that the pressure change (Δp) caused by the actuator (5) between the valve (2) and the actuator (5) ₃ ) And the pressure change (Deltap) in the chamber (4) ₄ ) In relation to each other,

-a delay in the occurrence of pressure variations in said one chamber; and/or

-a pressure change in the one chamber results in a smooth pressure drop in the one chamber (4).

7. Method according to any of the preceding claims, characterized in that the pressure change (Δp) caused by the actuator (5) between the valve (2) and the actuator (5) ₃ ) At a frequency and causing a pressure change (Δp) in the one chamber (4) at another frequency ₄ )。

8. The method according to any of the preceding claims, characterized in that the actuator (5) is positioned in the position of the actuatorPressure variation (Δp) caused between valve (2) and actuator (5) ₃ ) Forming a pressure curve (p) in the chamber (4) ₄ ) The pressure curve varies with delay, smoothly and with smaller amplitude and pressure offset.

9. Method according to claim 1, characterized in that the sensor element (6) does not detect the effect on the fluid (8) because the valve (2) is sealed.

10. Method according to any of the preceding claims, characterized in that the difference between the pressure characteristic in the one chamber (4) and the pressure characteristic between the valve (2) and the actuator (5) is compared with a threshold value (Y).

11. Method according to claim 10, characterized in that the pressure offset (Δp) of the sensor element (6) is taken into account.

12. Method according to any of the preceding claims, characterized in that the pressure (p) in the one chamber (4) is taken before the actuator (5) is activated ₄ ) And the pressure (p) between the valve (2) and the actuator (5) ₃ ) And preferably by the two pressures (p ₃ 、p ₄ ) The pressure offset (Δp) is obtained.

13. Method according to claim 12, characterized in that the pressure (p) in the chamber (4) is obtained ₄ ) And the pressure (p) between the valve (2) and the actuator (5) ₃ ) The time integral of the difference between them and then compared in particular with a threshold value (Y).

14. Method according to any of the preceding claims, characterized in that a time profile of the action of the actuator (5) on the further chamber (3) between the actuator (5) and the valve (2) and a time profile of the action of the actuator (5) on the one chamber (4) are obtained and the degree of correlation of the time profile is deduced from the obtained characteristics.

15. A method according to any of the preceding claims, characterized in that the degree of correlation of the time profile is obtained by means of machine learning.

16. A computer program for performing all the steps of one of the methods according to any one of claims 1 to 15, or programmed to perform the method according to any one of claims 1 to 15 when said computer program is run on a computer.

17. A machine readable storage medium on which a computer program according to claim 16 is stored or on which a computer program according to claim 16 is stored for use in a method according to claims 1 to 15.

18. A controller for performing all steps of one of the methods according to any one of claims 1 to 15 or programmed for use in a method according to any one of claims 1 to 15.