Realtime measurement of short chain alcohols in lubricating fluid systems

Abstract

The invention relates to a system, a sensing unit and a method, where the combination of a warning sensor with an identification sensor is used to detect presence of short chain alcohols in a lubricating fluid system. The warning sensor can be based on a membrane / polymer diffusion impedance / capacitance technology for water / moisture measurement, and the identification sensor can be based on electrical impedance principles to measure / characterize the dielectric properties of the lubricating fluid at various frequencies. The warning sensor can detect whether water or short chain alcohols are present while the identification sensor can detect whether the warning is caused by water or by a short chain alcohol.

Description

[0001] Realtime measurement of short chain alcohols in fluid

[0002] Background for the invention

[0003] The global need for reducing the CO2 emission has led to the introduction of various alternatives to fossil fuels used in internal combustion engines. Some of the alternatives are short chain alcohols and / or esters or ethers thereof. These short chain alcohols and / or esters or ethers thereof can be manufactured by power-to-X technology, bioethanol production and the like. Such fuels have the advantage of being made from renewable resources and they are therefore finding their ways into the transportation industry by being used as ship fuels, fuels for trucks and other machineries.

[0004] The introduction of such short chain alcohols and / or esters or ethers thereof introduces a risk that short chain alcohols can contaminate engine / machinery lubricating fluid systems also being used in the machinery.

[0005] As is well-known by the person skilled in the art, the alcohols are a break-down product from esters and ethers. Hence, using esters or ethers as fuel will also introduce the risk of short chain alcohol contamination.

[0006] The main parts of a lubricating fluid system are; a fluid reservoir where the fluid is stored when not in circulation, a fluid pump taking suction from the fluid reservoir and pumping the fluid under pressure through the lubrication system, a fluid filter that removes impurities and particles that can damage the engine, and a lubricating circuit consisting of ducts and galleries that carry the oil to the moving parts.

[0007] In engine lubricating oil systems, there is also a risk of contamination with water and therefore it is common practice to monitor possible water contamination and prepare preventive actions before reaching a limit, where it may impact the lubricating effect. The monitoring for water contamination may be done manually by taking samples with regular intervals or using a water-in oil sensor for continuous monitoring that can set a warning in the event of critical water contamination.

[0008] The lubricating fluid disclosed in this invention is a commercial engine lubricating oil, When a lubricant fluid system is contaminated with short chain alcohols, its lubricating effect changes significantly and hence in order to protect the machinery, it is vital to detect such a contamination fast. On the other hand, introducing selective alcohol sensors is expensive and there are a lot of interrupting components present in lubricating fluid systems that can disturb the measurements. Hence, there is a need for a fast, cheap, and reliable way of determining both the presence and optionally also the amount of short chain alcohols in the lubrication fluid systems.

[0009] Exposure and inhalation of short chain alcohol is also known to cause adverse health effects, also making it vital to detect such contamination of the lubricating fluid systems to protects operating, service, and maintenance engineers.

[0010] Known (commercially available) selective alcohol sensors are suitable for detecting or sniffing short chain alcohol vapor in a given atmosphere and not suitable for detecting short chain alcohols in a lubricating fluid system.

[0011] US20080289400A1 discloses a sensor system and a sensor method based on deflection of a piezo-resistive cantilever sensor for sensing a viscosity parameter in a lubricating oil. In other embodiments, the cantilever sensor may also be configured to detect oil contamination components such as ethanol or water by coating the cantilever with a chemical substance that interacts with the contaminating chemical. As the contamination chemical, such as ethanol or water, is absorbed, the coating will swell, deflecting the cantilever sensor corresponding to the amount of the contamination in the oil. With this technology, a sensor can detect only one specific chemical substance in a lubricating oil, for example ethanol or another example is water. In such a system, a viscosity sensor may alert that the lubrication fluid composition has changed, and a second sensor can identify if the cause is the presence of water, and a third sensor can identify if the cause is the presence of ethanol or other short- chain alcohol.

[0012] US2008 / 00532020A1 discloses a method for detecting two phasing as well as the onset of two phasing in a gasoline tank, where water and / or ethanol is present, primarily by using a capacitive sensor, measuring the impedance response according to the composition of the fluid. In particular, the method allows discrimination between fuel and / or fuel+additives such as ethanol, and ethanol+water mixtures, provided that response for each condition is known. Summary of the Invention

[0013] The present invention is based on a first sensor that can determine if the composition of the oil has changed and a second sensor that can identify if the cause is water or short chain alcohol. Both the first sensor and the second are based on well-proven technology and there is no requirement for a sensor calibrated for a given short chain alcohol to detect such contaminating of a lubricating system or of providing a third sensor.

[0014] The technology disclosed in this invention is particularly suited to mainstream engine lubricating system oil with base number below 20 mg KOH / g.

[0015] The inventors have found that by combining a warning sensor with an identification sensor, a cheap and reliable way of detecting short chain alcohols in a lubricating fluid system is provided.

[0016] According to the invention, a method is provided for detecting the presence of short chain alcohols in lubricating fluid systems, said method comprising the steps of:

[0017] Bringing a lubricating fluid into contact with a warning sensor and an identification sensor,

[0018] Measuring a first signal with the warning sensor,

[0019] Based on the first signal, determining whether there is a risk event, Measuring a second signal with the identification sensor,

[0020] Based on the second signal, determining whether the risk event is caused by water or a short chain alcohol.

[0021] Preferably, the first signal determines, whether there is a risk event caused by either water or a short chain alcohol.

[0022] The invention is based on the realization that a warning sensor can detect whether there is either a short chain alcohol or water present in the lubricating fluid system. However, the warning sensor cannot distinguish between water and short chain alcohols. Further, the warning sensor does not detect changes in components other than short chain alcohols or water. Hence, it provides a warning that there is either an amount of water or an amount of short chain alcohols present in the lubricating fluid system and thereby delivers a warning of a risk event. The identification sensor reacts to various components in the lubricating fluid systems, but is has a distinct difference in the sensor results to water and short chain alcohols. Hence, by combining the results collected with the warning sensor and the identification sensor, the presence of short chain alcohols can be determined. It is not important in which order the signals from the warning sensor and the identification sensor are collected and in which order the determination is done, it will lead to the same result.

[0023] If a warning from the warning sensor is determined, then it is known that there is either water or short chain alcohol present. If this is the case, then the identification sensor will also detect a change and based on that, it is known whether it is water or short chain alcohols that are the cause. If the order is reversed, then the identification sensor detects a change that can be caused by multiple components. If the warning sensor does not detect anything, then the change detected by the identification sensor is not caused by water or short chain alcohols and there is no need for fast action. If on the other hand, there is also a detection by the warning sensor it is known that the signal from the identification sensor is caused by water or short chain alcohols and the event caused can be determined.

[0024] This method enables a simple, cost-effective and fast real time detection of the presence of short chain alcohols in lubricating fluid systems.

[0025] The term short chain alcohol is meant to cover methanol, ethanol, propanol, isopropanol, butanol, iso-butanol and tert-butanol. Preferably, the short chain alcohols are methanol or ethanol. Most preferred, the short chain alcohol is methanol.

[0026] In a preferred embodiment, the short chain alcohol is methanol.

[0027] In another aspect, the invention relates to a method for detecting the presence of short chain alcohols in lubricating fluid systems, said method comprising the steps of:

[0028] Bringing a lubricating fluid into contact with a warning sensor and an identification sensor,

[0029] Measuring a first signal with the warning sensor,

[0030] Based on the first signal, determining whether there is a risk event caused by either water or a short chain alcohol,

[0031] Measuring a second signal with the identification sensor, Based on the second signal, determining whether the risk event is caused by water or the short chain alcohol.

[0032] In an even further aspect, a method relates to a method for detecting the presence of methanol in lubricating fluid systems, said method comprising the steps of:

[0033] Bringing a lubricating fluid into contact with a warning sensor and an identification sensor,

[0034] Measuring a first signal with the warning sensor,

[0035] Based on the first signal, determining whether there is a risk event caused by a component selected from the group consisting of water and methanol,

[0036] Measuring a second signal with the identification sensor,

[0037] Based on the second signal, determining whether the risk event is caused by water or methanol.

[0038] By using calibration, it is also possible to determine the actual amount of short chain alcohols and in particular the amount of methanol.

[0039] According to the invention, a method is provided to determine the amount of short chain alcohols present in a lubricating fluid system, said method comprising the steps of:

[0040] Bringing a lubricating fluid into contact with a warning sensor and an identification sensor,

[0041] Measuring a first signal with the warning sensor,

[0042] Based on the first signal, determining whether there is a risk event,

[0043] Measuring a second signal with the identification sensor,

[0044] Based on the second signal, determining whether the risk event is caused by water or a short chain alcohol,

[0045] Comparing the second signal with a laboratory-calibrated reference and based on said laboratory-calibrated reference, determining the amount of short chain alcohols present in the lubricating fluid system.

[0046] In a preferred embodiment, the warning sensor is a sensor based on a membrane / poly- mer diffusion impedance / capacitance technology for water / moisture measurement.

[0047] Examples of suitable identification sensors are sensors based on electrical impedance principles to measure / characterize the dielectric properties of the lubricating fluid at various frequencies or voltage / current excitation sensors to measure / characterize the dielectric properties of the lubricating fluid at a single frequency with different amplitudes.

[0048] In a preferred embodiment, the identification sensor is based on electrical impedance principles to measure / characterize the dielectric properties of the lubricating fluid at various frequencies.

[0049] In a preferred embodiment, the method further comprises the step of measuring the temperature in the lubricating oil. This has the advantage that it is possible to correct the measurements with the warning sensor and / or the identification sensor for temperature variations of the measured property e.g. the electrical impedance dependence on temperature.

[0050] According to the invention, there is further provided a sensing unit for determining presence of short chain alcohols in lubricating fluid systems, said sensing unit comprising:

[0051] - A warning sensor capable of measuring a parameter that can be used to detect whether water or short chain alcohols are present in the lubrication fluid system,

[0052] - An identification sensor capable of measuring a parameter that can be used to distinguish between presence of water and presence of short chain alcohols,

[0053] - An evaluation unit adapted to correlate the measured parameters and to evaluate whether a short chain alcohol is present or not.

[0054] Preferably, the warning sensor is capable of detecting whether water or short chain alcohols are present in the lubrication system without detecting other impurities in the lubrication system.

[0055] In a preferred embodiment, the sensing unit further comprises a temperature sensor.

[0056] In a preferred embodiment, the warning sensor for the sensing unit is a sensor based on a membrane / polymer diffusion impedance / capacitance technology for water / moisture measurement.

[0057] In a preferred embodiment, the identification sensor for the sensing unit is based on electrical impedance principles to measure / characterize the dielectric properties of the lubricating fluid at various frequencies. In another aspect, the invention relates to a system for determining the presence of short chain alcohols in lubricating fluid systems, the system comprising:

[0058] - A system inlet for receiving an inlet flow of lubricating fluid,

[0059] - A system outlet for releasing an outlet flow of tested lubricating fluid,

[0060] - A sensing unit for determining presence of short chain alcohols in lubricating fluid systems, said sensing unit comprising: o A warning sensor capable of measuring a parameter that can be used to detect whether water or short chain alcohols are present in the lubrication fluid system, o An identification sensor capable of measuring a parameter that can be used to distinguish between presence of water and presence of short chain alcohols, o An evaluation unit adapted to correlate the measured parameters and to evaluate whether a short chain alcohol is present or not.

[0061] In a preferred embodiment, the system further comprises a filtration unit in fluid communication with the system inlet and the system outlet, the filtration unit comprising a filter which is adapted to receive contaminated lubricating fluid and releasing filtered lubricating fluid.

[0062] Detailed description

[0063] In the following, the invention will be described in further details. The invention relates to the method for detecting the presence of short chain alcohols in lubricating fluid systems, a sensing unit adapted to carry out the method and a lubrication fluid system comprising a sensing unit adapted to carry out the method. The overall principle is based on the fact that a group of sensors responds with the same response to the presence of water or the presence of short chain alcohols, while other sensors respond differently to the presence of water or the presence of short chain alcohols. The last group of sensors (i.e. the identification sensors), however, also responds to the presence of other components in the lubricating fluid. Hence, a true determination of the presence of a short chain alcohol can only be done with the combination of a warning sensor and an identification sensor. Using only an identification sensor will result in false positive as the identification sensor also responds to components like particles, soot or the like. The table below illustrates the principle of the short chain alcohol detection based on a warning sensor and an identification sensor:

[0064] Where up represents an increase in the signal from the sensor and down represents a decrease. However, as is known to the person skilled in the art, a sensor can be configured to return the opposite signal. Hence, the principle will work equally well if the warning sensor is configured to return a decrease in signal instead of an increase. An example of such inversion is the electrical impedance sensor that can return the result as either the conductivity or the resistance. These two parameters relate to the same property but with opposite responses.

[0065] As can be seen from the table, water has the combination of up for the warning sensor and down for the identification sensor while short chain alcohols have the combination of up for the warning sensor and up for the identification sensor. This is also the case in if case other components causing the identification sensor to react are present, because the warning sensor will not react to presence of such components. Hence, by combining the inputs from the sensors, a simple, fast and reliable detection system is available.

[0066] Engine lubricating oil is typically designed to dissolve smaller amounts of water, such as 0.05% (500 PPM) or 0.1 % (1000 PPM) or 0.2% (2000 PPM) or 0.3% (3000 PPM) before risk of two-phasing of water and oil impacting the lubricating effect.

[0067] As well known, short chain alcohol is soluble in water. Should both water contamination and short chain alcohol contamination occur concurrently, the (critical) contamination will be identified as water contamination (at the onset of two-phasing of water and oil). As the signal from the warning sensor and / or the identification sensor can be temperature dependent, the reliability of the method can be further improved by adding a temperature sensor. The temperature sensor can be integrated in either the warning sensor or in the identification sensor or alternatively, it can be a separate sensor. The use of a temperature sensor is particularly important in cases where the lubricant fluid is prone to large temperature changes.

[0068] In a preferred embodiment, the method further comprises determination of the amount of short chain alcohols present in the lubricating fluid. Such determination can be done by comparing the response from the warning sensor and / or the identification of sensor with a laboratory-calibrated reference, a standard curve or a database with single or multiple calculated references. The advantage of a quantitative determination together with the warning is that a control system being either manually or automated can decide whether a shut-down of the engine / machinery is required or if the situation can be managed with increased cleaning or other counter measures e.g. addition of alcohol scavengers.

[0069] In a preferred embodiment, the evaluation unit further comprises means for comparing measured parameters from the sensors with reference data to make a quantitative determination of the amount of short chain alcohols present in the lubricating fluid. The means for comparing the measured parameters can be a processor unit that can calculate the amount based on datasets of signal output and concentration / amount of short chain alcohols. The datasets may consist of laboratory-calibrated references or data sourced from external databases.

[0070] List of figures

[0071] Figure 1 shows the laboratory set-up for an experiment in a system, where the warning sensor and the identification sensors are located in a fluid reservoir provided with an agitator system.

[0072] Figure 2 shows the laboratory set-up for an experiment in a system, where the reservoir is provided with a pump and a circulation line, and where the warning sensor and the identification sensor are located in the fluid circulation system.

[0073] Figure 3 shows the measurement result from a warning sensor and an identification sensor with MeOH injections from the set-up in figure 1. Figure 4 shows the measurement result from a warning sensor and an identification sensor with water injections from the set-up in figure 1

[0074] Figure 5 shows the measurement result from a warning sensor and an identification sensor with MeOH injections from the set-up in figure 2.

[0075] Figure 6 shows the measurement result from a warning sensor and an identification sensor with water injections from the set-up in figure 2.

[0076] Figure 7 shows the evolution of the relative humidity as a function of concentration of water and MeOH, respectively. Error bars represent one standard deviation of uncertainty. Where error bars are not shown, they are smaller than the data point, or replicas have not been performed. Figure 8 is an illustration of a sensing unit provided in a lubricating system fluid reservoir.

[0077] Figure 9 is an illustration of a sensing unit provided directly in the flow stream of the lubricating circulation system.

[0078] Figure 10 is an illustration of a lubricating system further comprising a cleaning system.

[0079] Figure11 is an illustration of a lubricating system further comprising a cleaning system and a parallel sensing unit.

[0080] Example 1

[0081] Example 1 applies to the set-up in figure 1.

[0082] The warning sensor and the identification sensor are submerged in a reservoir filled with a fixed amount of known lubricating fluid. An agitator system is provided in the reservoir to ensure constant circulation of the fluid in the reservoir. This lets the two sensors be in constant contact with the fluid and thus measure any changes in the fluid. The sensors are connected to a data collecting system. From this, the data is extracted in the form of graphs in real time.

[0083] At certain time intervals, a measured amount (400 ppm) of either water or short chain alcohol in form of MeOH is pipetted into the reservoir. After a given time, the same measured amount is pipetted into the reservoir again. This continues in steps of 400 ppm per injection. Figure 3 shows the results measured with a warning sensor, where the impedance is converted to relative humidity and an identification sensor based on inverse impedance principle. In the figure, at the vertical dashed line, there is a 400 ppm injection with a short chain alcohol in form of MeOH. As can be seen, the signal from the warning sensor increases sharply, when the short chain alcohol is introduced, i.e. creates a warning / event and / or change in response. At the same point in time, the dielectric properties measured with the identification sensor also increase sharply. Therefore, the two sensors both measure an increase after the injection. The same pattern follows after additional injections which then provide the basis for a quantification of the amount of short chain alcohols.

[0084] In summary, the plot in figure 3 shows the immediate response in trend when 400ppm MeOH is added to the lubrication fluid (grey dotted lines) for identification sensor (full line), sharp increase; and warning sensor (dashed lines), sharp increase.

[0085] Figure 4 shows the results measured with the same sensors as in figure 3, i.e. a warning sensor and an identification sensor. In the figure, at the vertical dashed line, there is a 400 ppm injection with water. It can be seen that after the injection, the signal from the warning sensor sharply increases, i.e. creates a warning. At the same point in time, dielectric properties measured with the identification sensor decreases. Therefore, the warning sensor measures an increase, while the identification sensor measures a decrease.

[0086] In summary, the plot in figure 4 shows the immediate response in trend when 400ppm water is added to the lubrication fluid (grey dotted lines) for identification sensor (full line), sharp decrease; and warning sensor (dashed lines), sharp increase.

[0087] Example 2

[0088] Example 2 applies to the set-up in figure 2.

[0089] From a reservoir filled with a fixed amount of known lubricating fluid, a pump is connected. This pump acts as a circulation pump and returns the pumped fluid back to the reservoir. The pump has a flow rate of 1 litre per minute. Between the reservoir and pump, thus being on the suction side of the string, the warning sensor and indicating sensor are submerged in a pipe. This lets them be in constant contact with the circulated fluid and thus measure any changes in the fluid. The sensors are connected to a data collecting system. From this, the data is extracted in the form of graphs in real time. The same procedure as in example 1 is applied, i.e. at certain time intervals, a measured amount (400 ppm) of either water or short chain alcohol in form of MeOH is pipetted into the reservoir. After a given time, the same measured amount is pipetted into the reservoir again. This continues in steps of 400 ppm per injection.

[0090] Figure 5 shows the results measured with the warning sensor and the identification sensor, where both sensors are based on exactly the same principles as described in example 1 . In the figure, at the vertical dashed line, there is a 400 ppm injection with a short chain alcohol in form of MeOH. As can be seen, the signal from the warning sensor again increases sharply, when the short chain alcohol is introduced, i.e. creates a warn- ing / event and / or change in response. At the same point in time, the dielectric properties measured with the identification sensor again increase sharply. Therefore, the two sensors both measure an increase after the injection. The same pattern follows after additional injections which then provide the basis for a quantification of the amount of short chain alcohols.

[0091] In summary, the plot in figure 5 shows the immediate response in trend when 400ppm MeOH is added to the lubrication fluid (grey dotted lines) for identification sensor (full line), sharp increase; and warning sensor (dashed lines), sharp increase.

[0092] Figure 6 shows the results measured with the same sensors as in figure 5, i.e. a warning sensor and an identification sensor. In the figure, at the vertical dashed line, there is a 400 ppm injection with water. It can be seen that after the injection, the signal from the warning sensor sharply increases, i.e. creates a warning. At the same point in time, dielectric properties measured with the identification sensor decreases. Therefore, the warning sensor again measures an increase, while the identification sensor measures a decrease.

[0093] In summary, the plot in figure 6 shows an immediate response in trend when 400ppm water is added to the lubrication fluid (grey dotted lines) for identification sensor (full line), sharp decrease; and warning sensor (dashed lines), sharp increase.

[0094] The warning sensor used in the laboratory experiments is a sensor based on principle to measure moisture, where the measurement principle is impedance converted to relative humidity for moisture detection. The identification sensor is based on electrical inverse impedance principle to meas- ure / characterize the dielectric properties of the lubricating fluid at various frequencies.

[0095] From example 1 and example 2 and figures 3 and 4 respectively figures 5 and 6 taken in combination, it can be seen that a warning is created when water or a short chain alcohol is present by the increase in the signal from the warning sensor. Afterwards it is identified whether the warning is caused by water or a short chained alcohol by the different reactions on the identification sensor.

[0096] The graphs in figure 7 show the evolution of the relative humidity (the warning sensor) as a function of concentration of water and methanol, respectively, representing data sets from both example 1 and example 2. An immediate ingress of water or methanol will lead to the warning sensor showing different responses. For water, few hundreds of ppm lead to an abrupt change in relative humidity (>80 % change) in the engine oil. For methanol, the response in warning sensor is less rapid at a few hundreds of ppm added to the motor oil. The saturation level for the warning sensor for water is reached at -2000 ppm and for methanol at -10000 ppm.

[0097] The results disclosed in example 1 and example 2 are based on conditions where water and short chain alcohol, respectively, are present in an emulsified state. The applied lubricating fluid is a commercially available lubricant characterized as a SAE30 (viscosity grade), with base number of 5 mg KOH / g.for use in diesel engine lubricating systems. In both examples, the temperature can be measured as an auxiliary. The method works without the temperature measurement, but its accuracy can be increased especially if the amount of short chain alcohols is to be quantified by reference to a laboratory-calibrated reference or a database.

[0098] In the following, the invention will be described in further details with reference to the figures.

[0099] Figure 8 is an illustration of a system according to the invention. There a lubricating system 1 with a circulation pump 3 is connected with a lubricating system fluid reservoir. The lubricating system 1 lubricates an engine or the like. The lubricating system further comprises an evaluation unit 6 that again comprises a warning sensor 4 and an identification sensor 5. In the version illustrated in figure 4, the testing is done in the lubrication system fluid reservoir. The advantage being that the system may monitor continuously also when the engine or the main circulating pump is not operated, but one must be aware that layering of fluids with different density may cause inaccurate measurements, when the lubricating fluid system is not operated. And when the lubricating fluid system is operated, foaming may disturb the measurements.

[0100] Figure 9 illustrates an alternative position of the evaluation unit 6 with its warning sensor 4 and identification sensor 5. There the monitoring is done directly in the flow of lubricating fluid in the lubricating system 1. With this position of the sensor system, the condition of the monitored fluid will always be representative for the components in the fluid system - but only when the engine or the main circulation pump is operated.

[0101] Figure 10 illustrates an embodiment of a system according to the invention. There the lubricating system 1 has a lubricating system fluid reservoir 2 from which the lubricating fluid with aid of a circulation pump 3 is conveyed to the device needing lubrication with the lubrication fluid. The sensing unit with the evaluation unit 6, the warning sensor 4 and the identification sensor 5 can be placed at any convenient position within the system. Most likely it is placed in conjunction with a cleaning system 8 such as a filter, a centrifugal separator system or other lubricating fluid cleaning systems. The cleaning system 8 can be in-line cleaning systems and / or off-line cleaning system 8. In figure 6, an offline cleaning system is illustrated. In the illustrated off-line cleaning system 8, an off-line cleaning system pump 7 is provided for circulation of the lubrication oil to be cleaned. The sensing unit is provided upstream of the cleaning system 8. In a particularly preferred embodiment, the sensing unit further comprises a temperature sensor. The advantage of this position is that the monitored fluid is representative for the fluid in the fluid reservoir also when the engine or the main circulating pump is not operated and the condition of the fluid system is continuously monitored, provided that the off-line cleaning system is operated.

[0102] Figure 11 illustrates an embodiment of the system from figure 6. There the sensing unit is provided in a separate loop i.e. in parallel position to the cleaning system 8. A sensor system supply pump 9 is provided in a separate loop. This setup has the advantage that it is easier to combine the sensing unit of the present invention, i.e. the sensing unit comprising a warning sensor 4, an identification sensor 5 and an evaluation unit 6 with other monitoring sensors. This can be sensors for determining the particulate contamination and / or other unwanted impurities. List of reference numbers

[0103] 1 Lubricating system

[0104] 2 Lubricating system fluid reservoir 3 Circulation pump

[0105] 4 Warning sensor

[0106] 5 Identification sensor

[0107] 6 Evaluation unit (calculate contamination condition)

[0108] 7 Off-line cleaning system pump 8 Cleaning system

[0109] 9 Sensor system supply pump

Claims

Claims1. A method for detecting the presence of short chain alcohols in a lubricating fluid system, said method comprising the steps of:Bringing a lubricating oil into contact with a warning sensor and an identification sensor,Measuring a first signal with the warning sensor,Based on the first signal, determining whether there is a risk event,- Measuring a second signal with the identification sensor,- Based on the second signal, determining whether the risk event is caused by water or a short chain alcohol.

2. A method according to claim 1 , where based on the first signal it is determined, whether there is a risk event caused by either water or a short chain alcohol.

3. A method according to any one of the preceding claims where the short chain alcohol is methanol.

4. A method according to any one of the preceding claims, where the short -, where the lubricating fluid system is a system oil with base number below 20 mg KOH / g.

5. A method according to any one of the preceding claims, where the method further comprises the step of measuring a temperature of the lubricating fluid.

6. A method according to any one of the preceding claims, where the warning sensor is a sensor based on principles to measure water / moisture I of lubricating fluids.

7. A method according to any one of the preceding claims, where the identification sensor is a sensor based on electrical impedance principles to measure / characterize the dielectric properties of the lubricating fluid at various frequencies.

8. A method according to any one of the preceding claims, where the warning sensor is a membrane / polymer diffusion impedance / capacitance sensor for water / moisture measurements.

9. A method for determining the amount of short chain alcohols present in a lubricating fluid system, said method comprising the steps of:Bringing a lubricating fluid into contact with a warning sensor and an identification sensor,Measuring a first signal with the warning sensor,Based on the first signal, determining whether there is a risk event,Measuring a second signal with the identification sensor,Based on the second signal, determining whether the risk event is caused by water or a short chain alcohol,Comparing the second signal with a laboratory-calibrated reference database and based on said laboratory-calibrated reference determining the amount of short chain alcohols present in the lubricating fluid system.

10. A method according to claim 9 that further comprises the step of measuring a temperature of the lubricating fluid.

11. A method according to any one of claim 9 or 10, where the warning sensor is a sensor based on principles to measure water / moisture of lubricating fluids.

12. A sensing unit to determine presence of short chain alcohols in lubricating fluid systems, said sensing unit comprising:A warning sensor capable of measuring a parameter that can be used to detect whether water or short chain alcohols are present in the lubrication fluid system, An identification sensor capable of measuring a parameter that can be used to distinguish between presence of water and presence of short chain alcohols, An evaluation unit adapted to correlate the measured parameters and to evaluate whether or not a short chain alcohol is present.

13. A Sensing unit according to claim 12, wherein the warning sensor is capable of detecting whether water or short chain alcohols are present in the lubrication system without detecting other impurities in the lubrication system.

14. A sensing unit according to claim 12 or 13, where the sensing unit further comprises a temperature sensor.

15. A sensor unit according to any one of claims 12 to 14, where the warning sensor is a sensor based on principles to measure water / moisture of lubricating fluids.

16. A sensing unit according to any one of claims 12 to 15, wherein the evaluation unit further comprises means for comparing the measured parameters with reference data to make a quantitative determination of the amount of short chain alcohols present in the lubricating fluid.

17. A system for determining the presence of short chain alcohols in lubricating fluid systems, the system comprising:- A system inlet for receiving an inlet flow of lubricating fluid,- A system outlet for releasing an outlet flow of tested lubricating fluid,- A sensing unit for determining presence of short chain alcohols in lubricating fluid systems, said sensing unit comprising: o A warning sensor capable of measuring a parameter that can be used to detect whether water or short chain alcohols are present in the lubrication fluid system, o An identification sensor capable of measuring a parameter that can be used to distinguish between presence of water and presence of short chain alcohols, o An evaluation unit adapted to correlate the measured parameters and to evaluate whether or not a short chain alcohol is present.

18. A system according to claim 17, wherein the warning sensor is capable of detecting whether water or short chain alcohols are present in the lubrication system without detecting other impurities in the lubrication system.

19. A system according to claim 16 or 17, wherein the warning sensor is a sensor based on principles to measure water / moisture of lubricating fluids.

20. A system according to any one of claims 16 to 19, where the sensing unit further comprises a temperature sensor.

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