DE102018214221B4 - Method for checking a device designed to determine at least one fluid property - Google Patents

Abstract

Method for checking a device (100) designed to determine at least one property of a fluid, a mixture of fuel and additive for an internal combustion engine of a vehicle, which is designed to transmit an electromagnetic source signal into the fluid along a signal path (122) and receiving two reception signals that are received at different angles (150, 160) relative to the transmission path (122), to determine the at least one property of the fluid and to output a first property signal indicating the at least one property, the method comprising: - operating of the internal combustion engine (10) in such a way that during the checking of the device (100) the property of the fluid is at least partially predetermined, - determining the first property value based on the property signal of the device (100), - determining at least one second property value based on at least a company parameters of the internal combustion engine (10) and / or a further property signal of a further device (100) designed to determine at least one property of a fluid, and determining that the device (100) is faulty if the first property value of the at least one second Property value differs by more than a property threshold value.

Description

The present invention relates to a method and a device for determining at least one property of a fluid, in particular a fluid mixture, such as a fuel-additive mixture for internal combustion engines, gear oils with foreign particles, hydraulic fluids with foreign particles or any other fluid that is an emulsion, suspension or dispersion.

The analysis of fluid properties is an important application in the process control of technical systems, especially in the high pressure area. The automotive sector can be mentioned as an example, in which efforts are currently being made to provide emulsion injections in the internal combustion engine. In particular, the fuel for internal combustion engines can liquids such. B. water, are added to improve the combustion, the pollutant emissions and / or the temperature behavior of the combustion. An unstable emulsion, which is generated, for example, by a high-pressure fuel pump, is injected into the combustion chamber. However, such emulsions are not necessary over the entire operating range of the engine, so that such emulsions do not have to be provided permanently with the same composition. In particular, gradient phases, i. H. Phases in which the generation of the emulsion is started or stopped involve the risk that the internal combustion engine will be provided with a fluid whose properties are unstable and unknown.

For this purpose, it is known to analyze the lambda control and the combustion fluctuations in order to be able to draw conclusions about the composition of the emulsion. The attempt is made to record a consequence of fluctuations in the emulsion properties by means of these two parameters and to adapt the application subsequently.

From the EP 2 430 465 B1 a particle detection and calibration of sensors is known. The method known therefrom comprises monitoring the optical energy that is scattered by particles of a liquid sample with at least one optical sensor and detecting a change in the magnitude of the optical energy monitored with the at least one optical sensor, since the change in the magnitude changes in the particles in the liquid sample. In response to the detection of the change in magnitude, the calibration of the at least one optical sensor used to detect the controlled optical energy is initiated.

From the DE 20 2008 014 667 U1 a measuring device for determining the mass concentration of a particle collective in a measurement gas is known.

The DE 600 35 460 T2 describes an in-line particle detector.

It is an object of the present invention to provide a method with which a device designed to determine at least one fluid property can be checked with regard to the plausibility of its signals. It is also an object of the present invention to calibrate such a device based on the plausibility check of the signals.

This object is achieved with a method according to independent claim 1. Advantageous refinements are given in the subclaims.

The present invention is essentially based on the idea of an optical device which is designed to at least one property, such as. B. to determine a concentration ratio of a mixture, of a fluid, to check the functionality. In particular, at least one operating parameter of the internal combustion engine from a model can serve to draw a conclusion about the at least one property of the fluid and to compare the property determined in this way with the property determined by means of the device. If the property value determined by means of the device deviates from the property determined by means of the model by more than a threshold value, the device can be determined to be faulty.

Such defects in the device can be due to aging and can be caused, for example, by dirt particles that are deposited in the device. In addition, impairments of the optical path, such as scratches on coupling and decoupling devices, can lead to falsified measurement results.

Consequently, a method for checking a device designed to determine at least one property of a fluid, in particular a mixture of fuel and additive for an internal combustion engine of a vehicle, is disclosed, which is designed to transmit an electromagnetic source signal into the fluid along a signal path and Receiving two reception signals that are received at different angles relative to the transmission path, determining the at least one property of the fluid and outputting a first property signal indicating the at least one property. The method according to the invention comprises an operation of the internal combustion engine in such a way that the property of the fluid is at least partially predetermined during the checking of the device, determining the first property value based on the property signal of the device, determining at least one second property value based on at least one operating parameter of the internal combustion engine and / or another Property signal of a further device designed to determine at least one property of a fluid and a determination that the device is faulty if the first property value deviates from the at least one second property value by more than one property threshold value.

Because the property of the fluid is at least partially predetermined, an expected second property value can be compared with the first property value determined by means of the device and, for example, recalibrated if there is an excessive deviation from one another.

Consequently, a defective device can be recognized with the method according to the invention.

In a preferred embodiment of the method according to the invention, the at least one operating parameter on which the second property value can be determined based on the lambda value, the knock tendency, the fluid injection quantity, the exhaust gas temperature, the ignition angle, injection duration, and / or the rotational uniformity.

The method according to the invention preferably further comprises calibrating the device by means of the second property value if it has been determined that the device is faulty. In this context, calibration means that the first property value determined by means of the device is corrected with the second property value. For example, the first property value can be replaced with the second property value and can thus adapt or shift a characteristic curve stored in the device.

The fluid is preferably a mixture of fuel and additive which has a predetermined concentration ratio. It is even more preferred that the fluid is essentially fuel and essentially free of additives. When the internal combustion engine is operated in this way with only fuel, the device should output a corresponding concentration value. If not, the device can be determined to be faulty.

The property threshold is in a range from about 1% to about 30%, preferably in a range from about 10% to about 20%. It is most preferred if the plausibility of the measurement results of the device is checked dynamically and continuously, for example even with very small deviations of less than 1% from the at least one second property value.

In a further embodiment of the method, it is preferred that the device has a signal source which is designed to transmit an electromagnetic source signal into the fluid along a transmission path, a first signal receiving device which is designed to transmit a first received signal along a to the transmission path below a at least one second signal receiving device, which is designed to receive a second received signal along a second receiving path running at a predetermined second angle to the transmission path to receive, wherein the second received signal corresponds to the electromagnetic source signal scattered by the fluid at least partially along the second receiving path, wherein the predetermined first angle is not equal to the predetermined two th angle, and a determination device which is designed to determine the at least one property of the fluid at least partially based on the first received signal and the at least one second received signal.

• 1 eine perspektivische Ansicht einer zum Bestimmen von zumindest einer Eigenschaft eines Fluids ausgebildeten Vorrichtung zeigt,
• 2 eine Schnittansicht durch die Vorrichtung der 1 zeigt,
• 3 eine weitere Schnittansicht durch die Vorrichtung entlang der Linie III-III der 2 zeigt,
• 4 eine schematische Ansicht einer Brennkraftmaschine mit der in der 1 dargestellten Vorrichtung zeigt, und
• 5 ein beispielhaftes Ablaufdiagramm eines erfindungsgemäßen Verfahrens zum Plausibilisieren des Signals der in der 1 dargestellten Vorrichtung zeigt.

Other objects and features of the present invention will become apparent to those skilled in the art by practicing the present teachings and reviewing the accompanying drawings, in which:

• 1 shows a perspective view of a device designed for determining at least one property of a fluid,
• 2 a sectional view through the device of 1 shows,
• 3 a further sectional view through the device along the line III-III of 2 shows,
• 4th a schematic view of an internal combustion engine with that in FIG 1 shows device shown, and
• 5 an exemplary flow chart of a method according to the invention for checking the plausibility of the signal in FIG 1 shows device shown.

In the context of the present disclosure, the term “fluid” describes any fluid and any fluid mixture that can consist of several components. In particular, it contains homogeneous and heterogeneous fluids and fluid mixtures including, for example, emulsions, suspensions and dispersions. Examples are fluid mixtures of several liquids, such as. B. fuel and water, mixtures of at least one liquid and at least one solid, such as hydraulic oil with foreign particles, and mixtures of at least one liquid and at least one gas, such as. B. fuel with air bubbles to mention. Furthermore, the term “fluid” includes multiphase one-component fluids, such as. B. a partially frozen urea solution, in which the urea solution is partially liquid and partially in the form of ice crystals. In addition, the refrigerant of an air conditioning system can be cited here, which can change its physical state between liquid and gaseous and can therefore exist in several phases.

In the context of the present invention, the described device describes at least one specific property, the qualitative and / or quantitative composition of the fluid. Furthermore, the at least one property of the fluid can include the size distribution of a component present in the fluid. In this way, conclusions can be drawn about the degree of mixing or homogenization of the fluid or fluid mixture. In addition, it is within the scope of the present invention to determine the stability of the fluid, the mass composition of the fluid and / or the structural sizes of the fluid.

In the context of the present invention, the term “property value” describes a value that can indicate at least one physical and / or chemical property of the fluid. For example, the property value can indicate the concentration ratio of the fluid, the degree of mixing of the fluid and / or the size distribution of the droplets or solid particles in the case of a fluid present as an emulsion or suspension.

The 1 shows a perspective view of a device designed to determine the at least one property of the fluid 100 who have favourited an enclosure 110 has, in which one extends along a flow axis 102 (see also 3 ) extending flow channel 112 is arranged through which a fluid along the flow axis 102 can flow. The fluid is, for example, a fuel-additive mixture for an internal combustion engine 10 (please refer 4th ), which by means of a high pressure fuel pump 20th into a high pressure storage device 30th , such as a common rail, the internal combustion engine 10 can be promoted and which under high pressure by means of combustion chamber lines 32 , 34 , 36 , 38 and these associated injection devices (not explicitly shown) the combustion chambers 12 , 14th , 16 , 18th the internal combustion engine 10 can be fed. As additives that can be mixed with the fuel, water or an aqueous urea solution can be cited as examples.

In the in the 1 The embodiment shown is the flow channel 112 shown with a substantially rectangular cross-section. In further refinements of the device according to the invention, the flow channel has 112 a circular, oval, triangular and any other cross-sectional shape for flow channels 112 on.

Of the 1 can be seen that the device 100 also a signal source 120 has that in the 1 to 3 illustrated embodiment in the form of a light source such. B. an LED light source is provided. Alternatively, however, the signal source can be any signal source which is designed to emit an electromagnetic source signal into the fluid along a transmission path 122 (please refer 2 and 3 ) to send out. In the 1 are the connecting cables 121 the signal source 120 indicated schematically.

From the 1 also shows that the device according to the invention 100 also a first signal receiving device 130 which is designed to send a first received signal along a to the transmission path 122 at a predetermined first angle 150 (please refer 2 ) running first receive path 132 to recieve. The first received signal essentially corresponds to that of the fluid from the transmission path 122 in the first receive path 132 scattered electromagnetic source signal.

In the in the 1 to 3 In the embodiments shown, the predetermined first angle is 0 ° or 180 °, so that the first receiving path 132 essentially a straight line extension of the transmission path 122 is. In particular, is the first signal receiving device 130 relative to the flow channel 112 opposite to the signal source 120 arranged so that the first signal receiving device 130 can detect the extinction of the electromagnetic source signal. In the 1 are also the connecting cables 131 the first signal receiving device 130 indicated.

The device 100 further comprises a second signal receiving device 140 which is designed to send a second received signal along one to the transmission path 122 at a predetermined second angle 160 (please refer 2 ) running second receiving path 142 to recieve. The second received signal essentially corresponds to that of the fluid from the transmission path 122 into the second receive path 142 scattered electromagnetic source signal. In the 1 are also the electrical connection cable 141 the second signal receiving device 140 indicated.

It is preferred that the predetermined first angle 150 unequal to the predetermined second angle 160 is. In addition, it is preferable that the predetermined first angle 150 and the predetermined second angle 160 not symmetrical to the transmission path 122 are arranged.

In further refinements, further second signal receiving devices can be provided, which are each designed to receive further second received signals along further second receiving paths. The angles between the send path 122 and the plurality of second reception paths 142 each can be different.

With reference to the 2 showing a sectional view through the device according to the invention 100 of the 1 represents, can be seen that the signal source 120 , the first signal receiving device 130 and the second receiving device 140 each in corresponding recesses in the housing 110 are used. In the in the 1 to 3 The illustrated embodiment are both the first signal receiving device 130 as well as the second signal receiving device 140 each designed as light-sensitive photodiodes which are each set up to generate a first response signal or a second response signal based on the first received signal or the second received signal. The first and second response signals are generated by means of the electrical connection line 131 or the electrical connection cables 141 to a determination unit (not explicitly shown in the drawings), which is then designed to determine the at least one property of the fluid at least partially based on the first received signal or first response signal and the at least one second received signal or second response signal. In particular, the determination unit is designed to output a received signal which indicates the at least one property of the fluid or corresponds to a first property value of the fluid.

In the 2 the send path falls 122 with the section line III-III together. In addition, the 2 be taken that the second receive path 142 at the predetermined second angle 160 to the send path 122 runs. In the example shown, the predetermined second angle is 160 about 90 °. In further refinements, the predetermined second angle can 160 be every corner.

The device 100 also has one of the signal sources 120 assigned and also on the housing 110 attached coupling device 124 which is designed to transfer the electromagnetic source signal, in particular the light emitted by the LED source, into the through the flow channel 112 coupling flowing fluid. Similarly, one of the first signal receiving devices 130 assigned and also on the housing 110 attached first decoupling device 134 and one of the second signal receiving means 140 assigned and also on the housing 110 attached second decoupling device 144 intended. The first decoupling device 134 is designed to decouple the first received signal from the fluid and to the first signal receiving device 130 to direct. The second decoupling device is corresponding 144 designed to decouple the second received signal from the fluid and the second signal receiving device 140 forward.

The coupling device 124 , the first decoupling device 134 and the second decoupling device 144 are each provided as conically shaped glass elements that fit into corresponding recesses in the housing 110 are used. It is preferred that the respective cone of the coupling device 124 , the first decoupling device 134 and the second decoupling device 144 is arranged such that the end with the larger diameter the flow channel 112 is facing. It can thereby be ensured that in the case of a fluid flowing under high pressure, the respective conically shaped glass elements are relative to the flow axis 102 at least partially radially outwards against the correspondingly conically shaped recesses in the housing 110 pressed and thus a fluid seal between the glass elements and those in the housing 110 provided recesses can be improved. Accordingly, the signal source can 120 , the first signal receiving device 130 and the second signal receiving means 140 compared to that in the flow channel 112 flowing fluid are arranged fluid-tight.

Although in the design of the 1 to 3 the send path 122 , the first receive path 132 and the second receive path 142 each perpendicular (ie radial) to the flow axis 102 run, it can be advantageous in other embodiments according to the invention if the transmission path 122 and / or the first receive path 132 and / or the second receive path 142 at non-perpendicular angles (ie, not radial) to the flow axis 102 run away. For example, it may be preferred to provide a further second receiving device which receives a further second received signal along a further second receiving path that is to the flow axis 102 does not run vertically, whereas the second receive path 142 the second receiving device 140 still perpendicular to the flow axis 102 runs.

The 3 shows a cross-sectional view of the device according to the invention 100 along the line III-III of the 2 . In the 3 the arrow points 103 the direction of flow of the fluid through the fluid channel 112 along the flow axis 102 on. The device 100 is designed to be arranged in a fuel supply system in an internal combustion engine in such a way that the flow channel 112 the device according to the invention 100 corresponds to at least part of the fuel line. This can be done in the housing 110 corresponding connection arrangements are provided, such as flanges, threaded bores, etc. Alternatively, the device according to the invention forms 100 part of a fluid line that conducts the fluid to be measured. It can also be possible that the flow channel 112 at least part of a fluid container, e.g. B. an oil pan or a hydraulic oil reservoir, in which the fluid to be measured is located.

The 4th shows schematically an internal combustion engine 10 with a high pressure fuel pump 20th that sucks fuel from a fuel tank, not shown, and delivers it under high pressure. In addition, the internal combustion engine 10 an additive injection device (not explicitly shown) which is designed to deliver an additive, such as. B. water, in the fuel upstream of the high pressure fuel pump 20th inject. Consequently, the high-pressure fuel pump is designed to deliver fuel or a mixture of fuel and additive into a high-pressure storage device 30th to promote, which is designed to store the fuel or the fuel-additive mixture and via the combustion chamber line 32 , 34 , 36 , 38 the combustion chambers 12 , 14th , 16 , 18th the internal combustion engine 10 feed.

The internal combustion engine 10 also has an outlet tract (not shown) for discharging and post-treating the exhaust gases from the internal combustion engine 10 on.

The 5 shows an exemplary flow chart of a method according to the invention for checking the functionality of the device 100 . That is, with the method according to the invention, the device 100 output signals can be checked for plausibility.

The method according to the invention starts at step 300 and then comes to the step 310 where the device 100 outputs a signal indicative of the at least one property of the fluid. In particular, based on that of the device 100 output signal a first property value can be determined. A property value can indicate, for example, the concentration ratio of the fuel-additive mixture or the degree of mixing of the fuel-additive mixture.

At a subsequent step 320 At least one second property value can be determined on the basis of at least one operating parameter of the internal combustion engine. The operating parameter can include, for example, the lambda value, the knock tendency, the fluid injection quantity, the exhaust gas temperature, the ignition angle, injection duration and / or the rotational uniformity. The determination of the at least one second property value is preferably based on an operating parameter of the internal combustion engine in order to be able to draw conclusions about the composition of the fluid or fluid mixture. Alternatively or additionally, the internal combustion engine 10 at least one other device 100 be assigned, which outputs a property signal, on the basis of which a second property value can be determined. For example, the device 100 in the combustion chamber line 32 be arranged, the further device 100 in one of the combustion chamber lines 34 , 36 , 38 can be arranged.

On a next step 330 the first property value is compared with the second property value. If the first property value deviates from the second property value by more than a property threshold value, the step 340 determines that the device 100 is faulty. The property threshold value can, for example, be in a range from approximately 1% to approximately 30%, preferably in a range from approximately 10% to approximately 20%.

Are two or more devices 100 provided, can at the crotch 340 that device 100 determined to be defective, its property value from the property values of the other devices 100 deviates the most. The process then ends at step 350 .

In a preferred embodiment, after determining that the device 100 is faulty, a calibration of this faulty device 100 respectively. To this end, it can be advantageous to pass a fluid through the device 100 to promote that has predetermined or known properties. For example, a fuel-additive mixture with a known concentration ratio can be delivered. Furthermore, it can be advantageous, instead of a fuel-additive mixture, to only deliver fuel that is free from additive (s).

When the fluid with known properties is conveyed, the second property value determined via the at least one operating parameter can then be used as a calibration value for the device 100 serve. Alternatively, when pumping fuel without an additive, that of the device 100 determined first property value can be used as calibration value (zero offset).

Claims (7)

Method for checking a device (100) designed to determine at least one property of a fluid, a mixture of fuel and additive for an internal combustion engine of a vehicle, which is designed to transmit an electromagnetic source signal into the fluid along a signal path (122) and receiving two received signals, which are received at different angles (150, 160) relative to the transmission path (122), to determine the at least one property of the fluid and to output a first property signal indicating the at least one property, the method comprising: - Operating the internal combustion engine (10) in such a way that the property of the fluid is at least partially predetermined while the device (100) is being checked, - determining the first property value based on the property signal of the device (100), - determining at least one second property value based on at least one operating parameter of the internal combustion engine (10) and / or a further property signal of a further device (100) designed to determine at least one property of a fluid, and - Determining that the device (100) is faulty if the first property value deviates from the at least one second property value by more than a property threshold value. Procedure according to Claim 1 , wherein the at least one operating parameter, on the basis of which the second property value can be determined, has: lambda value, knock tendency, fluid injection quantity, exhaust gas temperature, injection duration, ignition angle and / or rotational uniformity. Method according to one of the preceding claims, further comprising: - Calibrating the device (100) by means of the second property value if it has been determined that the device (100) is defective. A method according to any one of the preceding claims, wherein the fluid is a mixture of fuel and additive having a predetermined concentration ratio. Method according to one of the Claims 1 to 3 wherein the fluid is fuel and free of additives. Method according to one of the preceding claims, wherein the property threshold value is in a range from about 1% to about 30%, preferably in a range from about 10% to about 20%. Method according to one of the preceding claims, wherein the device (100) comprises: - A signal source (120) which is designed to transmit an electromagnetic source signal into the fluid along a transmission path (122), - A first signal receiving device (130) which is designed to receive a first received signal along a first receiving path (132) extending to the transmission path (122) at a predetermined first angle (150), the first receiving signal being that of the fluid along the first Receiving path (132) corresponds to scattered electromagnetic source signal, - At least one second signal receiving device (140) which is designed to receive a second received signal along a second receiving path (142) extending to the transmission path (122) at a predetermined second angle (160), the second receiving signal at least partially that of the fluid corresponds to the electromagnetic source signal scattered along the second receiving path (142), the predetermined first angle (150) not being equal to the predetermined second angle (160), and - a determination device which is designed to determine the at least one property of the fluid at least partially based on the first received signal and the at least one second received signal.

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