Engine oil consumption and condition monitoring

Abstract

This invention relates to a method for determining the lubricating oil conditions of a stationary gas engine, the method comprising the following steps: retrieving lubricating oil temperature information and retrieving lubricating oil level information from a lubricating oil level sensor, wherein the lubricating oil level sensor is a capacitive sensor, and a step of normalizing the lubricating oil level information based on the lubricating oil temperature information.

Description

Technical Field

[0001] This invention relates to a method for determining the lubricating oil conditions of a stationary gas engine. Furthermore, this invention relates to a stationary gas engine comprising a non-transitory computer-readable storage medium. Background Technology

[0002] Machine condition monitoring has become important for maintaining and extending the health of reciprocating machinery, especially stationary gas turbines. Real-time monitoring of machine health can significantly reduce operating costs by eliminating the need for costly machine downtime for inspections, which would otherwise be necessary to avoid the possibility of excessive component fatigue or failure during operation.

[0003] Engine oil condition is one of the parameters that provides a broad understanding of the health of mechanical components affected by relative motion. Besides oil condition, oil consumption is also a key indicator of component and engine health. Furthermore, since changes in oil can lead to engine shutdowns, predicting the remaining oil life is important. Being able to anticipate upcoming engine repairs or oil changes significantly benefits engine operation planning. Monitoring oil parameters helps prevent unexpected engine shutdowns.

[0004] Over time, lubricating oils undergo degradation, a process also known as aging. The three main mechanisms that lead to lubricating oil aging are oxidation, water contamination, and particulate contamination.

[0005] As an example, referring to particulate contamination, small wear debris particles with sizes ranging from 1 to 10 μm are typically generated during normal wear machine operation, while abnormal wear generates particles larger than 10 μm. The particle size and size gradually increase over time until machine failure. Based on this trend, lubricant degradation due to particulate contamination can be monitored by continuously analyzing the amount and size of wear particles present in the lubricating oil.

[0006] Lubricant analysis has become an effective means of providing early warnings in the progression of failures because it contains valuable information about the aging and damage of moving parts wetted by lubricant.

[0007] For this purpose, a dedicated lubricating oil quality sensor is known, which is installed on the engine to monitor a portion of the lubricating oil from the continuously circulating lubricating flow in situ during operation.

[0008] However, although dedicated lubricant quality sensors can indeed provide comprehensive and detailed information about lubricant conditions, these dedicated sensors are expensive and, in many cases, difficult to modify for existing stationary gas engines. Summary of the Invention

[0009] Considering the existing technology, the objective is to provide an improved method for determining the lubricating oil conditions of a stationary gas engine in a simple, robust, and cost-effective manner, preferably with the possibility of modifying an existing stationary gas engine. Furthermore, the objective is to provide a stationary gas engine that implements this method.

[0010] This objective is achieved by the stationary gas engine according to the present invention and the method for determining the lubricating oil conditions of the stationary gas engine according to the present invention. Preferred embodiments are described in this specification and the accompanying drawings.

[0011] Therefore, a method for determining the lubricating oil conditions of a stationary gas turbine engine is provided. The method includes the steps of retrieving lubricating oil temperature information, retrieving lubricating oil level information from a lubricating oil level sensor, wherein the lubricating oil level sensor is a capacitive sensor, and normalizing the lubricating oil level information based on the lubricating oil temperature information.

[0012] Additionally, a stationary gas engine is provided, comprising at least one lubricating oil temperature sensor and at least one lubricating oil level sensor of the type of capacitive sensor, as well as a computing device and a non-transitory computer-readable storage medium encoded with data and instructions, which, when executed by the computing device, causes the computing device to execute the method. Attached Figure Description

[0013] The invention will be more readily understood when considered in conjunction with the accompanying drawings, which are described in the following detailed description:

[0014] Figure 1 A diagram illustrating the retrieval of lubricating oil temperature information from the ETSI lookup table is shown schematically.

[0015] Figure 2 A flowchart illustrating a method for determining lubricating oil consumption is shown schematically.

[0016] Figure 3 A diagram illustrating the calculation of lubricating oil level information is shown schematically.

[0017] Figure 4 A flowchart illustrating a method for determining changes in lubricating oil is shown schematically.

[0018] Figure 5 A flowchart illustrating a method for determining abnormal lubricating oil conditions according to a first embodiment is shown schematically.

[0019] Figure 6 A diagram illustrating a method for determining abnormal lubricating oil conditions according to a second embodiment is shown schematically.

[0020] Figure 7 A diagram illustrating the determination of the dielectric constant value of the lubricating oil is shown schematically; and

[0021] Figure 8 A diagram illustrating the determination of abnormal lubricating oil conditions is shown schematically. Detailed Implementation

[0022] The invention will now be explained in more detail with reference to the accompanying drawings. In the drawings, the same elements are indicated by the same reference numerals, and repeated descriptions thereof may be omitted to avoid repetition.

[0023] Figure 1 A diagram illustrating the retrieval of lubricating oil temperature information 10 from the ETSI (Engine Condition Temperature Indicator) lookup table 12 is shown schematically. This lookup table 12 includes a first row containing reference engine lubricating oil temperature values ​​and subsequent rows containing temperature reference values. The ETSI diagram 14, containing all temperature reference values, can be populated based on the engine cooling circuit design. In other words, the engine lubricating oil temperature signal 16 measured in the engine is not directly used as lubricating oil temperature information 10, but rather a temperature reference value is retrieved from the ETSI lookup table 12 as lubricating oil temperature information 10. Therefore, this value can be used as lubricating oil temperature information 10 in the step of retrieving lubricating oil temperature information S10. As a result, the Engine Condition Temperature Indicator (ETSI) can be used as the normalization step S30 (… Figure 1 Enabler (not shown in the image).

[0024] The term Engine Condition Temperature Indicator (ETSI) can be used equivalently to describe the temperature of the engine and the lubricating oil reservoir.

[0025] Figure 2 A flowchart illustrating a method for determining lubricating oil consumption is shown schematically. The engine's operating status can be monitored when starting the engine. Once the engine is running, Figure 2 The algorithm described herein can be effective and can continue to check the engine temperature status related to the engine lubricating oil temperature. More specifically, the Engine Condition Temperature Indicator (ETSI) information is retrieved in retrieval step S10. In the illustrated embodiment, the retrieved ETSI value is then checked against a predetermined threshold during the waiting step S100.

[0026] Once the required threshold for the ETSI value is reached, according to Figure 2 The algorithm can wait for counter 110 to become valid. Counter 110 can be a simple function of time and can be calibrated to have values ​​stored and processed at desired time intervals. Simultaneously, lubricating oil level information, which can be used as a sensor output, can be stored in storage step S120.

[0027] The lubricating oil level information can be stored in a ring memory. According to the illustrated embodiment, the ring memory can, for example, store up to n values ​​at a time and can operate on a first-in, first-out (FIFO) principle. Subsequently, in step S130, the lubricating oil level difference ΔL is determined at predetermined time intervals. The determined lubricating oil level differences can also be stored. In step S140, lubricating oil consumption is determined by utilizing predetermined lubricating oil correlations.

[0028] This correlation can include the correlation between engine oil level and oil volume, as well as a further correlation between volume and weight. Additionally, a power generator counter can be provided using generator power signals and operating hours. Thus, oil consumption can be calculated based on g / kWh.

[0029] Figure 3 A diagram illustrating the calculation of lubricating oil level information is shown schematically. Such calculations can be applied to determine S130, etc. Figure 2 The steps discussed herein involve the difference in lubricating oil level at predetermined time intervals. According to... Figure 3 The example shown monitors the lubricating oil consumption of the engine and lubricating oil reservoir. For this purpose, at least the following input parameters are required: a) engine operating status, b) engine lubricating oil level, c) lubricating oil level in the lubricating oil reservoir, and d) the corresponding engine temperature status indicator (ETSI) information.

[0030] During the storage step, for example Figure 2 The storage step S120 shown can store lubricating oil level information 20 each time the engine stops and starts. Therefore, two values ​​of lubricating oil level information can be stored, namely lubricating oil level engine 1, OLE1 and lubricating oil level engine 2, OLE2. Similarly, two values ​​of lubricating oil level information are stored for the lubricating oil reservoir, namely lubricating oil level reserve 1, OLR1 and lubricating oil level reserve 2, OLR2.

[0031] Alternatively or additionally, during storage step 120, the lubricating oil level information 20 may be stored not only each time the engine stops and starts, but also—or alternatively—based on predetermined conditions (e.g., operating hour intervals). For this purpose, the values ​​of those lubricating oil level information obtained from lubricating oil level engine 1 and lubricating oil level engine 2 may be stored. Similarly, the values ​​of the lubricating oil level information are stored for the lubricating oil reservoir.

[0032] like Figure 3As shown in the table, the engine's operating hours are also stored. Finally, lubricant consumption can be calculated by considering the lubricant level in the reservoir ΔR = OLR1 - OLR2 and the difference in operating hours associated with that operating period. The sum of all volume differences ∑ΔR divided by the relevant operating hours ΔHr can then be converted to lubricant consumption in g / kWh, provided that the density of the lubricant and the work generated are also stored.

[0033] Figure 4 A flowchart illustrating a method for determining changes in lubricating oil is shown schematically. According to... Figure 4 The example shown checks whether there has been a change in the lubricating oil in the engine and lubricating oil reservoir.

[0034] Figure 4 A flowchart illustrating a method for detecting changes in lubricating oil is shown schematically. The engine's operating status can be monitored during engine start-up. Once the engine is running, Figure 4 The algorithm described herein can be effective and can continue to check the engine temperature status related to the engine lubricating oil temperature. More specifically, the Engine Condition Temperature Indicator (ETSI) information is retrieved in retrieval step S10. In the illustrated embodiment, the retrieved ETSI is then checked against a predetermined threshold during the waiting step S100. Subsequently, lubricating oil level information that can be used as a sensor output can be stored in the storage step S120.

[0035] In monitoring step S150, the change in lubricating oil level is monitored between engine stop conditions and subsequent engine start conditions. In this step, it is possible to continuously check whether a change in lubricating oil level has occurred between engine stop conditions and subsequent engine start conditions. Possible parameters in monitoring step S150 may include, for example, the change in lubricating oil level and the maximum difference ΔL in lubricating oil level.

[0036] If the lubricating oil level in the engine or lubricating oil reservoir is confirmed to be empty or nearly empty during engine shutdown, a lubricating oil change can be indicated. Therefore, if the lubricating oil level drops below a predetermined threshold during monitoring step S150 during the start-end stop conditions, a lubricating oil change can be indicated in indication step S160. For example, if the lubricating oil level engine value drops below 10% of the initial lubricating oil level in the engine, a lubricating oil change can be indicated. Additionally or optionally, if the lubricating oil level in the lubricating oil reservoir drops below 10% of its initial value, a lubricating oil change can be indicated. In this case, the method may include indication step S160 indicating that a lubricating oil change has occurred.

[0037] Furthermore, the counter used for subsequent lubricant changes can be updated in the update step S170, which includes the normalization step S30. This allows the lubricant life counter to be reset. Similarly, engine operating hours can be stored in the remaining operating hours until the next lubricant change can be updated. Additionally, the updated lubricant remaining service life (RUL) value based on the predetermined lubricant life and operating hours can be calculated in the update step S170.

[0038] According to Figure 4 Further steps, not shown, may be provided for checking any active diagnostics or anomalies of the lubricating oil level sensor in order to make the lubricating oil change indication qualified step S160.

[0039] Figure 5 A flowchart illustrating a method for determining abnormal lubricating oil conditions according to a first embodiment is shown schematically. When the engine condition indicator is activated, determining the ETSI information means performing the step S10, retrieving the lubricating oil temperature information. In this specific case, the lubricating oil temperature information is retrieved in the form of engine temperature condition indicator ETSI information, as described above. Figure 1 As described in the discussion. Simultaneously, or in a subsequent step, in retrieval step S20, lubricating oil level information is retrieved from the capacitive sensor.

[0040] In the normalization step S30, the dielectric constant value of the lubricating oil is obtained to detect anomalies in lubricating oil degradation. The voltage output of the sensor capacitor is used to sense the dielectric constant value of the lubricating oil. The sensing of this value is normalized on the lubricating oil temperature (ETSI) within the normalization step S30. Subsequently, in the determination step S200, the dielectric constant value of the lubricating oil is obtained from a predetermined reference degradation map. In the identification step S210, it is determined whether the dielectric constant value of the lubricating oil is outside the acceptable threshold of the reference degradation map.

[0041] The dielectric constant of the lubricating oil takes into account several physical properties of the lubricating oil. It is based on the value of a physical signal capacitance sensor, which can then be normalized according to the lubricating oil temperature information.

[0042] This capacitive lubricating oil level sensor can be configured to measure various performance parameters, such as viscosity, wear particle quantity, total acid value, or pH value, by means of changes in dielectric constant.

[0043] The dielectric constant, also known as the inductance, can be calculated by measuring the capacitance of a lubricating oil level sensor in the form of a capacitive sensor.

[0044] As a general rule, with increasing pollution, abrasive particles, total acid value or pH value, oxidized water pollution or particulate pollution lead to different dielectric constants.

[0045] Before performing identification step S210, an experimental design of experiment (DOE) can be provided to investigate the effects on the dielectric constant of the lubricating oil and the capacitance provided by a capacitance sensor. Furthermore, the latter must be performed on various lubricating oil samples at different temperatures and degradation stages. This data is used to develop a physical model of one or more lookup table shapes. In return, the values ​​provided within the lookup table can be used as factors to normalize the effects of various parameters in order to clearly observe the effect of degradation on capacitance. Again, as the output of this lookup table, the lubricating oil dielectric constant value is obtained. For this purpose, a predetermined graph for acceptable dielectric constant values ​​can be provided based on experimental tests.

[0046] Furthermore, continuous checks can be performed to determine whether the determined real-time dielectric constant value is within an acceptable threshold or deviates from its expected curve. If an abnormal trend is detected, a lubricant sample testing request is triggered in step S220, which indicates that sample testing is required.

[0047] Figure 7 A diagram illustrating the use of a lookup table to obtain the dielectric constant value of the lubricating oil is shown schematically. As described above, normalization occurs during normalization step S30.

[0048] The lookup table includes a first row containing the Engine Temperature Status Indicator (ETSI) value. The second row lists the lubricating oil dielectric constant values ​​for a given ETSI value. The third row provides a reference value from the lubricating oil condition for each ETSI value, with the default condition set to 0.1. The lowest row provides the sensor value ε corresponding to a given ETSI value. To retrieve the temperature normalized to the lubricating oil dielectric constant value, the sensor value ε is plotted relative to temperature in the first step. In the second step, the sensor value ε is normalized relative to temperature by multiplying the lubricating oil condition by the ETSI value. The result is a single value, referred to as ε. N Therefore, the default state for lubricating oil is set to 0.1, and the default state for ETSI is set to 1.0. The initial oil state can be updated using a separate algorithm after oil changes or additions. The default oil state can be defined as 0.1.

[0049] Figure 8 A diagram illustrating the determination of abnormal lubricating oil conditions is shown schematically. To determine abnormal lubricating oil conditions, a reference degradation chart is required. This reference degradation chart may include a first row covering the lubricating oil values ​​over a given operating hour and a second row covering the lubricating oil dielectric constant values ​​for that given operating hour. For each lubricating oil, this reference degradation chart must be experimentally determined to examine various SAE40 lubricating oils. Furthermore, various applications must be examined to find a suitable deviation window.

[0050] Can represent Figure 8The graph depicted in the figure is used to interpret and determine whether the lubricating oil is in an abnormal state. Based on this graph, the normalized sensor value ε is plotted relative to the operating hours. N Combining the reference degradation map introduced above, the desired curve (solid line) and the allowable deviation curve (dashed line) are obtained. The curves shown in the figure can be obtained through a regression function of the data points stored in the degradation map, and based on experimentally determined conditions for a given lubricant.

[0051] Therefore, if the dielectric constant of the lubricating oil is detected to be outside the indicated threshold, and thus follows an abnormal trend to the extent that it exceeds the allowable deviation curve, an abnormal lubricating oil condition is indicated.

[0052] It will be apparent to those skilled in the art that these embodiments and items merely depict examples of a variety of possibilities. Therefore, the embodiments shown herein should not be construed as limiting these features and configurations. Any possible combination and configuration of the described features can be selected according to the scope of the invention.

[0053] A method for determining lubricating oil conditions in a stationary gas turbine engine can be provided. The method includes the following steps:

[0054] - Steps for retrieving lubricating oil temperature information

[0055] - Retrieve lubricating oil level information from the lubricating oil level sensor.

[0056] The lubricating oil level sensor is a capacitive sensor. Furthermore, the method includes the following steps:

[0057] - Standardize the lubricating oil level information based on the lubricating oil temperature information.

[0058] When starting the engine, its operating status can be monitored. Once the engine is running, methods for determining lubricating oil conditions can be effective, and this process can continue to retrieve lubricating oil temperature and level information. Lubricating oil temperature information can be retrieved from a temperature sensor, and lubricating oil level information can be retrieved from a lubricating oil level sensor, which functions as a capacitive sensor.

[0059] Similar to temperature sensors, lubricating oil level sensors are readily available in stationary gas engines. More specifically, in the applicant's prior art stationary gas engines, capacitive temperature sensors and lubricating oil level sensors are provided. Such lubricating oil level sensors are standard components that provide output information corresponding to the lubricating oil level in the stationary gas engine or lubricating oil reservoir.

[0060] Typically, stationary gas engines include additional sensors for determining lubricating oil conditions. However, providing such additional sensors comes with higher costs and increased complexity.

[0061] Capacitive sensors are widely used to detect changes in the physical properties of liquid media. Simply put, the capacitive sensor according to the present invention can detect changes in the conductivity of a medium. For this purpose, the sensor may include two adjacent probes that are conductive and in contact with the medium to be measured. During measurement, a voltage can be applied to the probes. If the properties or mixture of the contact medium changes, the conductivity of the contact medium changes. Therefore, the change in conductivity can be measured by the voltage change at the sensor probes, and corresponds to the change in the medium in contact with the probes.

[0062] Therefore, using such a capacitive sensor, which has already been implemented in engines, represents a cost-effective and simple source of information, upon which methods for determining lubricating oil conditions can be performed.

[0063] By standardizing the lubricating oil level information based on the lubricating oil temperature information in the standardization step, a robust method can be provided, and this method can also be implemented cost-effectively.

[0064] The proposed method can be used in stationary gas engines and in the lubricating oil reservoirs of stationary gas engines. However, the method is not limited to this application and can be used in conjunction with any engine, such as stationary or mobile engines, gas propellant or liquid propellant driven engines, or reciprocating or continuously operating engines.

[0065] The retrieved lubricating oil temperature information and / or the retrieved lubricating oil level information can be understood as signals retrieved directly or indirectly from the sensor.

[0066] Specifically, lubricating oil temperature information can be provided as Engine Temperature Status Indicator (ETSI) information retrieved from an ETSI lookup table, preferably wherein the lookup table comprises an ETSI diagram filled based on a predetermined engine cooling circuit design. This engine temperature status indicator information can be used as an enabler for the normalization process. In the broadest sense, ETSI information can refer to the value of temperature status in a dimensionless representation.

[0067] As an example, the ETSI lookup table may include a header row and at least one subsequent row, the header row including a reference engine oil temperature value, and the subsequent rows including dimensionless values ​​corresponding to the reference engine oil temperature value. In other words, instead of directly using the oil temperature value as the oil temperature information, the latter is indirectly obtained from an ETSI lookup table in the form of dimensionless ETSI values. For different reference temperature ranges and for a given oil, an ETSI graph can be populated within the ETSI lookup table.

[0068] Alternatively, the ETSI lookup table may also include information on different lubricants. In this case, it may be necessary to retrieve information about the lubricant currently used in the engine or reservoir.

[0069] In a further development, the method can include a step of waiting after engine start until the lubricating oil temperature reaches a predetermined temperature threshold. This avoids the method from generating continuous false alarms, for example, due to the engine not being in a steady-state operating mode. Furthermore, the temperature threshold can be varied depending on the type of lubricating oil used in the engine. Therefore, the temperature threshold can be changed or adjusted to suit new lubricating oils. Changing the temperature threshold does not require changing the algorithm implemented by the method.

[0070] The lubricating oil temperature information can be retrieved from the engine and / or lubricating oil reservoir. Similarly, the temperature threshold can include temperature data obtained from the engine or lubricating oil reservoir.

[0071] The following describes the determination of lubricating oil consumption using the disclosed method. Therefore, lubricating oil conditions may include conditions representing lubricating oil consumption. To this end, the method may further include the following steps:

[0072] -Wait for the counter to become valid.

[0073] - Store at least one lubricating oil level information.

[0074] - Determine and store the differences in lubricating oil levels at predetermined time intervals, and

[0075] - The lubricant consumption is determined by utilizing a predetermined lubricant correlation.

[0076] Preferably, the counter can be a function of time and can be calibrated to store and process values ​​at desired time intervals. Furthermore, at least one stored lubricating oil level information can be in the form of sensor output. The determination of lubricating oil level differences can be made at predetermined time intervals and can also be stored. This predetermined lubricating oil correlation can include lubricating oil characteristics utilizing similar density, lubricating oil type, and engine oil pan details. This correlation can include the correlation between engine oil level and lubricating oil volume, and further, the correlation between volume and weight. Additionally, a power generation counter can be provided using generator power signals and operating hours. Thus, lubricating oil consumption can be calculated based on g / kWh.

[0077] In a further development, during this storage step, the at least one lubricating oil level information is stored in a ring memory, preferably wherein the ring memory can store n values ​​at a time, and preferably wherein the ring memory operates according to the first-in, first-out (FIFO) principle. This ensures that there are sufficient data points available in the memory. Furthermore, it guarantees that the correct data points are used in the processing of lubricating oil information.

[0078] Alternatively or additionally, the differences in lubricating oil levels can be determined at predefined time intervals, and the determined differences in lubricating oil levels can also be stored. This yields a consistent dataset, which can then be used for data post-processing purposes.

[0079] In another embodiment, the lubricating oil conditions may include conditions representing the detection of changes in lubricating oil. The method may further include the following steps:

[0080] - Store at least one lubricating oil level information.

[0081] - Monitor changes in lubricating oil level between engine stop conditions and subsequent engine start conditions, and

[0082] If the lubricating oil level drops below a predetermined threshold during this monitoring step,

[0083] - Indication (S160) indicates that a change in lubricating oil has occurred.

[0084] If a change in the lubricating oil is detected,

[0085] - Update (S170) the counter for subsequent lubricant changes.

[0086] Based on the lubricating oil conditions determined by this algorithm, it should be indicated whether any changes in lubricating oil occurred during the subsequent engine start-up and shutdown process. This provides a fail-safe and convenient way to update service intervals.

[0087] Due to the nature of lubricant changes, an indication that a lubricant change has occurred requires that the engine and / or lubricant reservoir be empty during engine shutdown and subsequent start-up. For example, a lubricant change can be confirmed if the engine oil level I value drops to less than 10% of the initial lubricant level in the engine and / or lubricant reservoir. In any case, the value can be conveniently selected such that potential residual lubricant remaining in the engine or reservoir can be considered without leading to erroneous results.

[0088] In a preferred development, the method may further include a step of checking for any active diagnostics or anomalies in the lubricating oil level sensor to ensure the lubricating oil change indication step is qualified. This avoids false alarms. The method for determining whether a lubricating oil change has occurred can always be initiated, excluding any lubricating oil level sensor power failure or malfunction—which could potentially trigger a signal equivalent to that of an empty engine or reservoir.

[0089] According to another embodiment, lubricating oil conditions may include a state indicating abnormal lubricating oil conditions. To this end, the method may further include the following steps:

[0090] - Determine the condition of the engine oil; and

[0091] - Identifying that the lubricating oil condition is an abnormal lubricating oil condition preferably includes the following subsequent steps:

[0092] - Indicates that a sample test is required.

[0093] In this way, any abnormal lubricating oil conditions that can be detected by a capacitive lubricating oil level sensor can be determined using only lubricating oil temperature and level information. In other words, there is no need to install a dedicated liquid lubricating oil quality sensor in the engine or lubricating oil reservoir. This provides a convenient, inexpensive, and robust method for detecting abnormal lubricating oil conditions.

[0094] Further developments include obtaining the dielectric constant of the lubricating oil in the standardization step, and obtaining the dielectric constant of the lubricating oil from a predetermined reference degradation map in the determination step. Additionally, in the identification step, it is determined whether the dielectric constant of the lubricating oil is outside the acceptable threshold of the reference degradation map.

[0095] It is known in the prior art that conventional capacitive lubricating oil level sensors can detect a wide range of changes in physical properties and the presence of contaminants in the lubricating oil. For example, it is known that acid value, iron content, and moisture content in lubricating oil lead to an increase in dielectric constant. Therefore, changes in dielectric constant may be related to abnormal conditions.

[0096] According to another embodiment, the reference degradation map may include a lookup table comprising degradation curves as a function of operating hours, preferably wherein these degradation curves represent experimentally determined conditions for the lubricating oil. To quantify lubricating oil conditions, changes in dielectric constant, expressed as variations in the lubricating oil level sensor voltage, can be identified within a specific degradation map. Therefore, for a given lubricating oil, a predetermined degradation over time can be provided. This has the advantage that if one type of lubricating oil is replaced by another, only the degradation map needs to be updated, not the algorithm or method itself.

[0097] According to a further embodiment, the degradation curve can be based on a regression function. The regression function allows for convenient interpolation of data points obtained from individual experiments. Therefore, a continuous function can be implemented even for data ranges without specific experimentally obtained data points. This saves time and effort in filling in the degradation map.

[0098] Preferably, lubricating oil level information can be provided as a processed signal, particularly a pulse width modulation (PWM) signal, as output information corresponding to a given lubricating oil level. The processed signal can be any signal that has been modified, altered, multiplied, filtered, cut, separated, or selected based on the original signal provided by the probe. The advantage of using a processed signal is that the chaotic original signal provided by the probe can sometimes be processed before being used in subsequent applications. Therefore, the obtained lubricating oil level information can be processed and analyzed more conveniently. For this purpose, pulse width modulation (PWM) is a method of reducing the average power transmitted by an electrical signal by effectively separating it into discrete components. The advantage of using a PWM signal is that capacitive pulses generated by contaminants, droplets, or sudden changes in fill height in the lubricating oil are softened within the signal output. Therefore, the obtained lubricating oil level information can be processed and analyzed more conveniently.

[0099] Furthermore, a stationary gas turbine engine includes at least one lubricating oil temperature sensor and at least one lubricating oil level sensor of the type of capacitive sensor, as well as a computing device and a non-transitory computer-readable storage medium encoded with data and instructions, which, when executed by the computing device, causes the computing device to perform the aforementioned method. Therefore, the technical features described in conjunction with the method for determining lubricating oil conditions can also be applied to the proposed stationary gas turbine engine, and vice versa.

[0100] Therefore, the technical features described in conjunction with the above methods can also be applied to the proposed construction machinery and / or computer systems, and vice versa.

[0101] Therefore, the technical features described in conjunction with the above methods can also be applied to the proposed construction machinery and / or computer systems, and vice versa.

[0102] Industrial applicability

[0103] Referring to the accompanying drawings, the method for determining lubricating oil conditions as described above can be applied to any suitable engine, such as a stationary gas engine.

Claims

1. A method of determining a lubricating oil condition of a stationary gas engine, comprising the steps of - retrieving lubricating oil temperature information, and - retrieving lubricating oil level information from a lubricating oil level sensor, wherein the lubricating oil level sensor is a capacitive sensor, characterized in that a step of normalizing the lubricating oil level information according to the lubricating oil temperature information, wherein the lubricating oil temperature information is provided as ETSI (Engine Temperature Status Indicator) information retrieved from an ETSI lookup table, wherein the ETSI lookup table comprises an ETSI map populated based on a predetermined engine cooling circuit design, wherein the method further comprises a step of waiting until the lubricating oil temperature information reaches a predetermined temperature threshold after starting the engine, wherein the lubricating oil condition comprises a condition indicative of a lubricating oil change detection, wherein the method further comprises the steps of: - storing at least one lubricating oil level information; - monitoring a change in lubricating oil level between an engine stop condition and a subsequent engine start condition; and wherein if the lubricating oil level drops below a predetermined threshold during the monitoring step, - indicating that a lubricating oil change has occurred, wherein if a lubricating oil change is detected, - updating a counter for a subsequent lubricating oil change.

2. The method according to claim 1, wherein the lubricating oil condition comprises a condition indicative of a lubricating oil consumption, wherein the method further comprises the steps of: - waiting for a counter to be valid; - storing at least one lubricating oil level information; - determining a difference in lubricating oil level at predetermined time intervals and storing the difference; and - determining the lubricating oil consumption by utilizing a predetermined lubricating oil correlation.

3. The method according to claim 2, wherein in the storing step, the at least one lubricating oil level information is stored in a ring memory.

4. The method according to claim 3, wherein the ring memory is capable of holding n values at a time.

5. The method according to claim 3, wherein the ring memory operates according to a first-in-first-out principle.

6. The method according to claim 1, further comprising a step of checking (S180) any active diagnostics or abnormalities of the lubricating oil level sensor in order to qualify the lubricating oil change indication step.

7. The method according to claim 1 or 2, wherein the lubricating oil condition comprises a condition indicative of an abnormal lubricating oil condition, wherein the method further comprises the steps of: - determining an engine lubricating oil status; and - identifying that the lubricating oil condition is an abnormal lubricating oil condition.

8. The method according to claim 7, wherein the method comprises the following subsequent steps: - indicating that a sample test is required.

9. The method according to claim 7, wherein - in the normalizing step, a lubricating oil dielectric constant value is obtained, - in the determining step, a lubricating oil dielectric constant value is obtained from a predetermined reference degradation map; and - in the identifying step, it is determined whether the lubricating oil dielectric constant value is outside an acceptable threshold of the reference degradation map.

10. The method according to claim 9, wherein the reference degradation map comprises a look-up table comprising degradation curves as a function of operating hours.

11. The method according to claim 10, wherein the degradation curves represent experimentally determined conditions of the lubricating oil.

12. The method according to claim 10, wherein the degradation curves are based on a regression function.

13. The method according to claim 9, wherein the reference degradation map is designed such that it takes into account the effect of lubricating oil lubrication contaminants of at least one of wear particles, oxidation particles, acid number, pH value and water content.

14. The method according to any one of claims 1 to 6, wherein the lubricating oil level information is provided as a processed signal as output information corresponding to a given lubricating oil level.

15. The method according to claim 14, wherein the processed signal is a pulse width modulated, PWM, signal.

16. A stationary gas engine comprising at least one lubricating oil temperature sensor and at least one lubricating oil level sensor of the capacitive sensor type and a computing device and a non-transitory computer readable storage medium encoded with data and instructions that, when executed by the computing device, cause the computing device to perform the method according to any one of claims 1 to 15.

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