DE102016212887B4 - Measuring arrangement for lubricating oil and measuring methods - Google Patents

Abstract

A measuring arrangement (14) for lubricating oil (8) in an oil circuit (6) of a plant (2), comprising a first sensor (16a) upstream of a plant component (4) to be lubricated by the lubricating oil (8) and downstream of an oil filter (10) the oil circuit (2) for a first value (W1) of a characteristic (K) of the lubricating oil (8) and a second sensor (16b) downstream of the system component (4) and upstream of the oil filter (10) for a second value (W2) same characteristic (K) of the lubricating oil (8), wherein the first (16a) and the second sensor (16b) is an ultrasonic sensor. In a method for determining the values (W1, W2), the first value (W1) upstream of the plant component (4) and downstream of the oil filter (10) is determined, and the second value (W2) downstream of the plant component (4) and upstream of Oil filter (10) determined, and the values determined by means of ultrasonic sensors.

Description

The invention relates to a measuring arrangement for lubricating oil in an oil circuit of a plant and a method for determining values of a characteristic for lubricating oil in an oil circuit of a plant.

Various plants, z. As vehicles or machines, each have an oil circuit for lubricating oil. The oil circuit contains a filtration system, eg. B. an oil filter.

Abrasive wear in equipment damages their system components until their function is limited. It is therefore the task of a system monitoring to detect the wear in good time before the abrasive wear causes irreversible damage.

From the DE 100 53 250 A1 an oil-state sensor device with an ultrasonic sensor is known, from whose sensor signal oil state variables are derived. As a result, a reliable predictions of the exhaustion of the oil or the necessary time of the oil change is possible and measures to protect the engine from wear, pollution and corrosion can be initiated.

From the US 2009/0241674 A1 It is known to aim at a rotary machine having a function to stably measure a degree of wear of a sliding surface in a slide bearing with high accuracy. Disclosed is a rotary machine including: a shaft rotated by a torque transmitted from a drive source, a bearing for supporting the shaft, an oil film portion between the shaft and the bearing, an ultrasonic sensor for applying an ultrasonic pulse to the sliding surface or to the reference step area available to the ultrasonic sensor installation surface and to receive an ultrasonic pulse reflected from the oil film section and a diagnostic unit to drive the ultrasonic sensor to compare a prestored intensity of the ultrasonic pulse in the oil film portion and an intensity of the ultrasonic pulse reflected from the oil film portion.

The publication DE 199 27 666 A1 discloses a method for determining the concentration of individual components in a liquid multicomponent system. In this case, a cuvette is filled with the liquid to be tested and tempered. Thereafter, the measurement of transit time and attenuation of the ultrasound in the medium takes place.

In the publication DE 199 06 940 A1 discloses an inspection method for determining the cleaning agent concentration of a liquid. Based on a viscosity measurement and the duration of ultrasound, a statement about the detergent concentration can be made.

From the publication DE 10 2007 045 837 A1 For example, a method is known that uses a condition monitoring device to monitor an oil lubricated component of an engine. The device uses a sacrificial component, the wear on the estimated life of the oil can be concluded.

The publication DE 10 2007 037 525 A1 , which forms the closest prior art, describes an oil filter system for filtering motor oil in motor vehicles. The oil filter system uses a sensor to measure the number and size of particles in the oil at the inlet to the filter element. Optionally, a second sensor is provided at the output of the filter. The filter may be, for example, an ultrasonic sensor.

The object of the invention is to improve the wear detection.

The object is achieved by a measuring arrangement according to claim 1. The measuring arrangement is one for lubricating oil in an oil circuit of a plant. The measuring arrangement contains a first sensor. The first sensor can be arranged upstream of a plant component to be lubricated by the lubricating oil. The first sensor is used to determine a first value of a characteristic of that lubricating oil that flows to the first sensor during operation of the system. The measuring arrangement contains a second sensor. The second sensor can be arranged downstream of the system component and serves to determine a second value of the same parameter of that lubricating oil which flows to the second sensor during operation of the system. The first sensor can also be located downstream of an oil filter of the oil circuit. The second sensor can also be arranged upstream of the oil sensor.

"Applicable" means that, when the measuring arrangement is installed as intended, the first and second sensors are actually arranged at the designated locations. "Up / Down" refers to the flow direction of the lubricating oil in the oil circuit during normal operation of the system. "In addition" means that both arrangement conditions apply to each sensor simultaneously or equally, ie both must be fulfilled. That is: The first sensor is located upstream of the system component and downstream of the oil filter when installed as intended. When properly installed, the second sensor is located downstream of the plant component and upstream of the oil filter. The first sensor is thus located in the flow path between the oil filter and the system component, the second sensor is located in the flow path between the system component and the oil filter.

"Systems" are to be understood in the broadest sense and are in particular vehicles and machines that have lubrication through an oil circuit.

The invention is based on the following findings or considerations:
There is currently no analytical method that can provide online information about wear particles in the system or detect such wear particles online. "Online" means in real time or with a maximum delay in seconds or minutes, ie promptly during operation. At present, an oil sample must be taken from the corresponding system, for example a machine with an oil circuit (oil is the lubricating oil). After sampling, the wear particles or corresponding elements must then be determined by means of optical analysis methods or spectroscopy, for example infrared spectroscopy, in an external laboratory. These methods are very time consuming and costly. Online analysis methods currently only analyze mass and magnetic properties.

There are currently measuring methods for the determination of the concentration and the size of particles by means of ultrasound. In such a method, the waves of different frequency are used for the determination of different particle sizes. The ultrasonic measuring principle uses transmitters with piezo element and receiver of the signal. After damping the signal, the particle size is determined. This method is problematic for use in oils, because there are other disruptive factors besides wear particles, such as air or water bubbles, which dampen the signal.

It is assumed that, when worn on the system component, the oil property of the oil which is detectable by the sensor and changes that of the system component, since, for example, it varies. B. contains more abrasive particles. However, the oil flowing out of the oil filter does not change its corresponding property, since the oil filter z. B. also retains the additionally abraded particles and thus still emits the same purified oil. According to the invention, this results in the advantage that wear on the system component can be detected. According to the invention, there is an application of two measuring methods in the oil circuit. Two measuring devices (first and second sensor) each measure a parameter, in particular a signal attenuation, one of which is in the oil circuit before and the other according to the system component, in particular a motor or tribological system installed. The measuring devices are installed before and after an oil filter, as the controlled, d. H. monitored or measured system (oil circuit) is equipped with a filtration. By comparing the two signals, the differences between filtered or oil at the inlet of the plant component and unfiltered or oil from the outlet of the plant component can be defined.

According to the invention, the first sensor and the second sensor are each an ultrasonic sensor. By an appropriate sensor, an ultrasonic characteristic can be determined on the lubricating oil. Corresponding parameters are particularly meaningful for the aging or wear condition of oils.

According to the invention, each sensor, or each ultrasonic sensor, has a transmitter and a receiver, and the transmitter and receiver are spaced apart by a measuring path. The measurement of the parameter supplying the sensor result takes place along this measuring path. In the case of an ultrasonic sensor, an ultrasonic pulse propagates along the measuring path. The measuring section runs at least in sections through the lubricating oil. In particular, the measuring section is a straight line. According to the invention, a transmitter is arranged on one side of an oil-carrying line in the case of an intended installation of the measuring arrangement and a receiver on another, in particular opposite, side of the line. Such a sensor or ultrasonic sensor can be particularly easily integrated into an oil circuit to be examined.

In a preferred variant of this embodiment, at least during the determination of a value, the lubricating oil is at least part of a medium, wherein the medium influences the detected ultrasonic attenuation of the sensor. By using the lubricating oil as a damping medium in the ultrasonic sensor, it is particularly easy to determine an ultrasonic damping of the lubricating oil.

In a preferred embodiment, the parameter is therefore the ultrasonic attenuation of the lubricating oil.

In a preferred embodiment, the measuring arrangement contains a comparison module. The comparison module is used to determine a comparison value of the first value and the second value. By comparing or comparing the two values, in particular in the case of electrical capacities, the differences between filtered lubricating oil or oil at the inlet of the Plant component (between oil filter and system component) and unfiltered oil or oil at the outlet of the system component (between system component and oil filter) are defined or determined. A corresponding comparison value is, for example, the difference between the first value and the second value or the amount of the difference.

In a preferred embodiment, the plant component is a motor or a tribological system. For such system components, the measuring arrangement is particularly suitable, since wear in such system components is usually detectable at the interplay of respective first and second measured values.

In a preferred embodiment, the oil circuit is part of the measuring arrangement. In other words, then an oil circuit is claimed with measuring arrangement.

In a preferred variant of this embodiment, the lubricating oil in the oil circuit is part of the measuring arrangement. In other words, then an oil circuit with lubricating oil and measuring assembly is claimed.

In a preferred embodiment, the system is part of the measuring arrangement. In other words, then a system (with oil circuit, optionally with lubricating oil) claimed with measuring arrangement.

The object of the invention is also achieved by a method according to claim 6. The method is used to determine values of a parameter for lubricating oil in an oil circuit of a plant, wherein the measuring arrangement according to the invention is used. In the method, a first value of the characteristic value of such lubricating oil is determined that is upstream of a system component to be lubricated by the lubricating oil. A second value of the same characteristic is determined on such lubricating oil, which is located downstream of the plant component. The first value is further determined on such lubricating oil that is downstream of an oil filter present in the oil circuit and the second value is determined on such lubricating oil that is upstream of the oil filter. The values, ie the first value and the second value, are respectively determined with the aid of a respective ultrasound sensor. The method and at least part of its embodiments as well as the respective advantages have been explained analogously already in connection with the measuring arrangement according to the invention.

In a preferred embodiment, first and second values are determined at a first time or at the same time. The first time is one at which the oil circuit is known to be in a proper condition. From these values, a first comparison value is formed. At least one later second time or at the same time, the first and second values are determined again and a respective second comparison value is formed. A measure is taken in such cases if the respective second comparison value deviates from the first comparison value by more than an allowable tolerance measure.

"Time" or "at the same time" means that no appreciable or measurable changes are to be expected in a possible period between measurements, at least with regard to changes in the properties of the lubricating oil. The measurements are considered to be simultaneous if they take place within a particular period up to one second, in particular one minute or in particular one hour.

In this context, "time" is understood as a period or any time within a period in which, as is known or expected, no changes in the oil quality or plant quality are to be expected.

A measure to be taken is, for example, the issuing of a warning message or an error message, a stop of the system, a repair or replacement of the system component, and so on.

At the first time, therefore, a first comparison value is determined as the reference value, wherein here all system parameters, properties of the lubricating oil, its specific consistency, temperatures, and so on, which could influence the measured values, are also included in the measured value. No further setting or presetting or selection of parameters or the like is required. Based on this reference value, the second measurements are carried out or the second comparison values are formed, in particular several times in succession. For each of the comparison values is respectively monitored or checked whether its difference to the first comparison value exceeds the allowable tolerance level or not. As long as this does not exceed the tolerance level, it is assumed that the system - from its intended condition - has not changed or has changed only insignificantly and therefore no measures have to be taken in this regard.

If the difference or deviation exceeds the tolerance, it is assumed that the oil circuit or the system component or the oil filter is no longer in the intended condition, eg. B. the oil is then more polluted by the plant component, what a Indication of increased wear in the component is. Then the defined action is taken.

In a preferred embodiment, the first and second values are determined by means of a respective passage measurement by the lubricating oil along a measuring path, in particular a straight line. Thus, in particular the o. G. Continuity sensor are used, the transmitter is attached to one and the receiver on another side of an oil-carrying line, etc.

In the context of the invention, lubricating oil is always mentioned here. However, the invention is analogously applicable to other lubricants in corresponding lubricant circuits.

Embodiments of the invention, also in combinations of the above-mentioned embodiments, if appropriate also previously not mentioned embodiments, are summarized as follows:
According to the invention, an online analysis method for measuring wear results from the determination of values of a parameter, in particular the ultrasonic damping, of the oil in an oil circuit of a plant. The first sensor or reference sensor is located in the oil circuit in an inlet line of the system component (filtered oil, which is supplied to the system component). This shows the ultrasonic damping of the oil in front of the engine or tribosystem. A working sensor is installed in the outlet circuit (the oil flowing from the system component, which is fed to the filter) and shows an altered by the wear of the ultrasonic damping of the oil.

It is assumed that the oil from the plant components, eg. B. from a motor or tribological system, flowing oil at normal conditions always has a standardized deviation with respect to the measured values of clean oil flowing from the oil filter. If the abrasion in the system component or the tribological system increases, the deviation signal (deviation from the first and second measured value) - or its amount - will also increase. This increase or increase then indicates an exceptional condition, i. H. a system that no longer functions as intended. Gas or water bubbles and other wear irrelevant factors are excluded from the analysis according to the invention, since their proportion does not change after filtration.

The sensors, in particular in the form of ultrasonic sensors, are thus installed not only in relation to the system components, but also in relation to the oil filter and the flow direction of the lubricating oil before and after the oil filter, since the system to be monitored is equipped with a filtration , According to the invention thus results in an application of sensors, in particular ultrasonic sensors, in the oil circuit. At least two sensors measure values of the parameter, in particular an ultrasonic attenuation. One of the sensors is provided or installed in the oil circuit upstream of the system component, the other according to the system component with respect to the flow direction of the lubricating oil.

Further features, effects and advantages of the invention will become apparent from the following description of a preferred embodiment of the invention and the accompanying figures. This shows in a schematic outline sketch:

1 a system with oil circuit and measuring arrangement according to the invention,

2 a chronological sequence of measurements.

1 shows a plant 2 with a plant component 4 , here a motor or alternatively a tribological system. The attachment 2 contains an oil circuit 6 with lubricant in the form of lubricating oil 8th , or the plant component 4 supplies or lubricates. The oil circuit 6 contains a filtration system, here an oil filter 10 , The lubricating oil 8th flows through during normal operation of the system 2 the oil circuit 6 in the direction of the arrows 12 ,

The lubricating oil 8th or the oil circuit 6 or the plant 2 is a measuring arrangement 14 assigned. The measuring arrangement 14 contains a first sensor 16a that is in the oil cycle 6 upstream of the plant component 4 and downstream of the oil filter 10 is arranged. The measuring arrangement 14 contains a second sensor 16b downstream of the plant component 4 and upstream of the oil filter 10 is arranged. In the flow direction 12 happens lubricant 8th So in a circuit the oil filter 10 , the first sensor 16a , the plant component 4 and the second sensor 16b until it returns to the filtration system 10 returned to be cleaned there.

The first sensor 16a determines a first value W1 a characteristic K, here an ultrasonic damping of the lubricating oil 8th , which is the first sensor during operation of the system 16a flows against. The second sensor determines in the same way 16b a second value W2 of the same characteristic K of the lubricating oil 8th which is in operation of the plant 2 the second sensor 16b flows against. The sensors 16a . 16b are ultrasonic sensors. The lubricating oil 8th forms at least during the determination of the values W1, W2 at least part of the detected ultrasonic attenuation of the sensors 16a . 16b influencing medium.

The measuring arrangement 14 contains a comparison module 18 , The comparison module 18 determines a comparison value VW of first value W1 and second value W2, in the example the comparison value is the difference amount VW = | W2 - W1 |.

The sensors 16a . 16b each contain a transmitter 102 , b and a receiver 102 , b. Regarding the oil circuit 6 or a leading oil line 106 are each the transmitter 100a , b on one side of the line and the receivers 102 , b at the other, here in a cross-sectional plane opposite side of the oil line 106 arranged. A measuring section 104a , b between the respective transmitter 100a , b and the receiver 102 , b runs through the oil line 106 and thus at least in sections by the lubricating oil 8th , First value W1 and second value W2 are thus determined by means of a respective passage measurement by the lubricating oil 8th along the measuring route ( 104a , b), here a straight line, determined.

2 illustrates symbolically on a time beam over the time t the following method: In a method for determining the values W1, W2 of the characteristic K for lubricating oil 8th in the oil circuit 6 the plant 2 becomes a first value W1 of the characteristic K on such lubricating oil 8th determined upstream of the plant component 4 and downstream of the filtration system 10 is located, so here at the first sensor 16a , The second value W2 of the parameter K is based on such lubricating oil 8th determined downstream of the plant component 4 and upstream of the filtration system 10 , here, for example, at the location of the sensor 16b located.

First value W1 and second value W2 are first determined at a first time t0 at which the oil circuit 6 or the plant component 4 or the plant 2 is known to be in a proper condition, so in particular "in order" is. In other words, the plant is at this time 2 in this regard, without errors or in a desired state. From the thus determined values W1, W2, a first comparison value VW0 is formed.

First value W1 and second value W2 do not actually have to be determined at the same point in time t0, but in particular within one second, within one minute or within one hour. At respective subsequent times t1, t2,..., Respective further value pairs W1, W2-in the above sense at the same time-are determined and respective comparison values VW1, VW2,... Are formed. As soon as the absolute value difference between the comparison values VW1, VW2,... And the first comparison value VW0 is greater than an allowable tolerance measure T, a measure M is taken. Here measure M is the implementation of a replacement of the system component 4 in the oil circuit 6 because of excessive wear.

At time t1, the difference in magnitude between VW1 and VW0 is smaller than the tolerance dimension T, which is why nothing is done symbolically represented by an X. At time t2, the difference in magnitude between VW2 and VW0 is greater than the tolerance measure T, which is why measure M is taken.

LIST OF REFERENCE NUMBERS

2

investment

4

plant component

6

Oil circuit

8th

oil

10

oil filter

12

arrow

14

measuring arrangement

16a

first sensor

16b

second sensor

18

comparison module

100a, 100b

transmitter

102a, 102b

receiver

104a, 104b

measuring distance

106

oil line

M

measure

T

of tolerance

t

Time

t0, t1, t2

time

VW, VW0, VW1, VW2

comparison value

W1, W2

value

K

parameter

Claims (8)

Measuring arrangement ( 14 ) for lubricating oil ( 8th ) in an oil circuit ( 6 ) of a plant ( 2 ), - with a first sensor ( 16a ), which upstream of a through the lubricating oil ( 8th ) to be lubricated plant component ( 4 ) the plant ( 2 ) and which serves to generate a first value (W1) of a characteristic (K) of the first sensor ( 16a ) during operation of the installation ( 2 ) oncoming lubricating oil ( 8th ), - with a second sensor ( 16b ) located downstream of the plant component ( 4 ), and which serves to generate a second value (W2) of the same characteristic (K) of the second sensor during operation of the system ( 16b ) oncoming lubricating oil ( 8th ), characterized in that The first sensor ( 16a ) additionally downstream of an oil filter ( 10 ) of the oil circuit ( 2 ) and - the second sensor ( 16b ) additionally upstream of the oil filter ( 10 ) can be arranged and - the first sensor ( 16a ) and the second sensor ( 16b ) is an ultrasonic sensor - the first sensor ( 16a ) and the second sensor ( 16b ) one transmitter each ( 100a . 100b ) and a receiver ( 102 . 102b ) and respective transmitter ( 100a . 100b ) and respective recipient ( 102 . 102b ) through a respective measuring section ( 104a . 104b ) are spaced from each other, - the transmitter ( 100a . 100b ) on one side of an oil line ( 106 ) and a receiver on another side of the oil line ( 106 ), - the measuring section ( 104a . 104b ) between the respective transmitter ( 100a . 100b ) and the recipient ( 102 . 102b ) through the oil line ( 106 ) runs and at least partially through the lubricating oil ( 8th ). Measuring arrangement ( 14 ) according to claim 1, characterized in that the lubricating oil ( 8th ) at least during the determination of a value (W1, W2) at least part of the detected ultrasonic attenuation of the first sensor ( 16a ) and the second sensor ( 16b ) influencing medium is. Measuring arrangement ( 14 ) according to one of the preceding claims, characterized in that the parameter (K) the ultrasonic attenuation of the lubricating oil ( 8th ). Measuring arrangement ( 14 ) according to one of the preceding claims, characterized in that the measuring arrangement ( 14 ) a comparison module ( 18 ), which serves to determine a comparison value (VW) of the first value (W1) and the second value (W2). Measuring arrangement ( 14 ) according to one of the preceding claims, characterized in that the plant component ( 4 ) is a motor or a tribological system. Method for determining first and second values (W1, W2) of a parameter (K) for lubricating oil ( 8th ) in an oil circuit ( 2 ) of a plant ( 2 ), in which a measuring arrangement according to any one of claims 1 to 5 is used, wherein - the first value (W1) of the characteristic (K) by means of the first sensor ( 16a ) of such lubricating oil ( 8th ), which is upstream of that through the lubricating oil ( 8th ) to be lubricated plant component ( 4 ), - the second value (W2) of the same parameter (K) with the aid of the second sensor ( 16b ) of such lubricating oil ( 8th ) located downstream of the plant component ( 4 ), characterized in that - the first value (W1) of such lubricating oil ( 8th ) located downstream of an oil circuit ( 6 ) existing oil filter ( 10 ), and - the second value (W2) of such lubricating oil ( 8th ), which is located upstream of the oil filter ( 10 ) is located. A method according to claim 6, characterized in that - first value (W1) and second value (W2) are determined at a first time (t0) at which the oil circuit ( 6 ) is known to be in a proper state and a first comparison value (VW0) of first value (W1) and second value (W2) is formed, - first value (W1) and second value (W2) at least one respective later second time (t1 , t2, ...) are determined and a respective second comparison value (VW1, VW2, ...) is formed, - a measure (M) is taken when the respective second comparison value (VW1, VW2, first comparison value (VW0) deviates by more than an allowable tolerance measure (T). A method according to claim 7, characterized in that the first value (W1) and second value (W2) by means of a respective passage measurement by the lubricating oil ( 8th ) along a measuring section ( 104a . 104b ) be determined.

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