Lubricant dilution detection system

Abstract

Lubricant dilution detection systems and methods are disclosed. A method (300) for detecting lubricant dilution of a lubrication system (14) includes detecting a shutdown event of the lubrication system (14). The method includes measuring lubricant pressure during the shutdown event. The method further includes determining lubricant dilution based on the measured lubricant pressure during the shutdown event. In accordance with a determination that there is lubricant dilution, the method includes outputting an indication of the lubricant dilution.

Description

Technical Field

[0001] This disclosure generally relates to lubrication systems, and more specifically, to a lubricant dilution detection system for such lubrication systems. Background Technology

[0002] Lubrication systems supply one or more pressurized lubricants to various moving parts (e.g., bearings, gears, etc.) to lubricate them. The lubricants (e.g., oils) used in lubrication systems can become diluted over time for various reasons. For example, liquid fuel (e.g., diesel fuel) from the engine's fuel system and / or coolant from the oil cooler may leak into the lubrication system and mix with the lubricant. This can reduce the viscosity of the lubricant and thus its lubricating ability. Consequently, moving parts may be damaged over time due to diluted lubricant. Current methods for detecting lubricant dilution may require manual testing of the lubricant using samples and / or may not adequately detect lubricant dilution.

[0003] Japanese Patent Application Publication No. 2004293394 (“'394 Publication”), published on October 21, 2004, describes an oil dilution prevention device for an engine. The oil dilution prevention device includes means for detecting parameters related to the dilution rate of the engine oil. This parameter may include the pressure of the engine oil during engine idling operation. The oil dilution prevention device of '394 Publication detects engine oil dilution when the engine oil pressure is equal to or less than a threshold during idling. However, the device of '394 Publication may not adequately detect lubricant dilution and / or may erroneously diagnose lubricant dilution.

[0004] The lubricant dilution detection system disclosed herein can solve one or more of the problems described above and / or other problems in the art. However, the scope of the present disclosure is defined by the appended claims, and not by the ability to solve any particular problem. Summary of the Invention

[0005] In one aspect, a method for detecting lubricant dilution in a lubrication system is disclosed. The method includes: detecting a shutdown event of the lubrication system; measuring lubricant pressure during the shutdown event; determining lubricant dilution based on the lubricant pressure measured during the shutdown event; and outputting an indication of lubricant dilution based on the determination that lubricant dilution exists.

[0006] In another aspect, a lubricant dilution detection system is disclosed. The system includes: a lubrication system; a sensor for measuring lubricant pressure in the lubrication system; and a controller configured to: detect a shutdown event of the lubrication system; measure the lubricant pressure during the shutdown event; determine lubricant dilution based on the lubricant pressure measured during the shutdown event; and output an indication of lubricant dilution based on the determination that lubricant dilution exists.

[0007] In another aspect, a method for detecting lubricant dilution in a lubrication system is disclosed. The method includes: detecting a shutdown event of the lubrication system when one or more operating conditions associated with the lubrication system decrease to below a shutdown event threshold; measuring lubricant pressure during the shutdown event; comparing the measured lubricant pressure with a lubricant dilution threshold to determine whether the measured lubricant pressure is less than the lubricant dilution threshold; determining lubricant dilution based on the determination that the measured lubricant pressure is less than the lubricant dilution threshold; and outputting an indication of lubricant dilution based on the determination that lubricant dilution exists. Attached Figure Description

[0008] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various exemplary embodiments and, together with the description, serve to explain the principles of the disclosed embodiments.

[0009] Figure 1 This is a schematic diagram of an engine system with a lubricant dilution detection system according to aspects of this disclosure.

[0010] Figure 2 It is used for Figure 1 A schematic diagram of an exemplary lubricant dilution detection system for an engine system.

[0011] Figure 3 A flowchart is provided illustrating the process for detecting... Figure 1 An exemplary method for diluting the lubricant in a system.

[0012] Figure 4A and 4B It is a graph of lubricant pressure versus engine speed during shutdown, according to one or more embodiments. Detailed Implementation

[0013] The foregoing general description and the following detailed description are exemplary and illustrative only, and do not limit the claimed features. As used herein, the terms “comprise,” “comprising,” “has,” “having,” “include,” “including,” or other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article of manufacture, or apparatus that includes a list of elements includes not only those elements, but may also include other elements not expressly listed or inherent to such process, method, article of manufacture, or apparatus. In this disclosure, unless otherwise stated, relative terms, such as “about,” “substantially,” and “approximately,” are used to indicate possible variations of ±10% in the stated values.

[0014] Figure 1 A schematic diagram of an engine system 10 with a lubricant dilution detection system 100 is shown. The engine system 10 includes an engine 12, such as an internal combustion engine. The engine 12 may include, for example, a diesel engine, a gasoline engine, a dual-fuel engine (e.g., an engine capable of operating on both gaseous and / or liquid fuels), or any other type of engine known in the art. The engine 12 can be used in generator applications, mobile machinery (e.g., vehicles), other types of heavy machinery or equipment, etc. Operation of the engine 12 can generate power. For example, the engine 12 may include one or more cylinders (not shown) and a crankshaft (not shown) for providing power to a flywheel (not shown), etc. Figure 1 As shown, engine system 10 also includes lubrication system 14, lubricant dilution detection system 100, and output indicator 16. Engine system 10 may include other components and / or systems, such as transmission systems and / or other mechanical systems including moving and / or rotating parts.

[0015] The lubrication system 14 may include a lubricant supply device 18 (e.g., a lubricant pan), a pump 20, and a filter 22, which are in communication with each other via a lubricant supply line 24 (e.g., a lubricant passage). The lubricant may include oil or any other type of liquid lubricant known in the art. The pump 20 may include a mechanical pump for pressurizing the fluid (e.g., the lubricant) to produce a flow of lubricant from the lubricant supply device 18 through the lubrication system 14. For example, the pump 20 may include a gear pump driven by a gear train from a crankshaft or other rotating component of the engine 12. Furthermore, the pump 20 may be driven by other means and may include, for example, an electrically driven pump, a hydraulically driven pump, and / or any other type of pump. The pump 20 may include a pressure regulating valve 26 for reducing and regulating the pressure of the lubricant leaving the pump 20 and reducing the pressure to a predetermined level, as described in further detail below. The valve 26 may receive a pressure signal from the lubricant supply line 24 (e.g., as shown by the dashed line connected to the valve 26), such that the valve 26 can be controlled by the pressure signal between an open position and a closed position for regulating the pressure to a predetermined level.

[0016] Lubricant supply line 24 may include a series of pipes or passages for supplying lubricant from lubricant supply device 18 to various components of engine 12. For example, lubrication system 14 may supply lubricant to crankshaft, piston, camshaft (not shown), bearing (not shown), and / or any other component of engine 12. Excess lubricant may flow back into lubricant supply device 18. Filter 22 may remove particulates or other contaminants from the lubricant to prevent damage to components of engine 12. It should be understood that lubrication system 14 may include any number and / or combination of valves or other components known in the art, such as one or more lubricant coolers (not shown), purge pumps (not shown), pressure reducing valves, and / or other types of filters (e.g., suction filters and / or centrifugal lubricant filters). Furthermore, although exemplary embodiments describe lubrication system 14 for engine 12, it should be understood that aspects of this disclosure can be used for lubrication systems of any other type of mechanical system (e.g., transmission system) having moving and / or rotating components.

[0017] As detailed below, output indicator 16 can indicate lubricant dilution in lubrication system 14. Output indicator 16 may include a display, instrument, light, speaker, etc. For example, output indicator 16 may indicate the value (numerical value, percentage, etc.) of lubricant dilution in lubrication system 14 and / or may indicate (e.g., via notification) when lubricant has been diluted. Indicator 16 may be located as part of engine system 10 (e.g., in the operator's cab of a mobile machine) and / or may be located away from engine system 10. Although only a single output indicator 16 is described herein, it should be understood that output indicator 16 may include one or more indicators and may include any type of indicator for indicating lubricant dilution in lubrication system 14.

[0018] The lubricant dilution detection system 100 includes a controller 104, such as an engine control module (ECM), and a sensor system 30 connected to the controller 104. The sensor system 30 may include one or more sensors for measuring operating conditions, such as pressure sensors, temperature sensors, flow sensors, speed sensors, etc. For example, the sensor system 30 may include a lubricant pressure sensor 32, an engine speed sensor 34, and / or a lubricant temperature sensor 36. The lubricant pressure sensor 32 may be located in the lubricant supply line 24 downstream of the pump 20 and can sense a value indicating the pressure of the lubricant in the lubrication system 14. The engine speed sensor 34 may be located at the crankshaft of the engine 12 and can sense a value indicating the engine speed. The engine speed sensor 34 may be located anywhere on the engine 12, such as on a crankshaft pulley, flywheel, camshaft, or crankshaft. The lubricant temperature sensor 36 may be located in the lubricant supply line 24 downstream of the pump 20 and can sense a value indicating the temperature of the lubricant in the lubrication system 14. For example, the lubricant temperature sensor 36 may directly sense the temperature of the lubricant. In some embodiments, the lubricant temperature sensor 36 can sense the temperature of the coolant in the cooling system (not shown) of the engine system 10. The temperature of the coolant can correspond to the temperature of the lubricant. As used herein, "lubricant temperature" can correspond directly to either the lubricant temperature or the coolant temperature, or both. It should be understood that sensors 32, 34, and 36 can include any type of sensor, such as a resistive sensor, an inductive sensor, a capacitive sensor, a piezoelectric sensor, an optical sensor, a microelectromechanical system sensor, etc. Furthermore, the sensor system 30 can include physical sensors and / or virtual sensors (e.g., sensors whose values ​​are indirectly determined by the controller 104 based on other sensed values), and can include any number and / or combination of sensors required to sense or measure operating conditions.

[0019] Figure 2A schematic diagram of an exemplary lubricant dilution detection system 100 for operating and / or controlling at least a portion of an engine system 10 is shown. System 100 may include input 102, controller 104, and output 106. Input 102 may include, for example, a lubricant pressure signal 110 from pressure sensor 32, an engine speed signal 112 from speed sensor 34, and a lubricant temperature signal 114 from temperature sensor 36. Output 106 may include, for example, a lubricant dilution indication signal 120. Controller 104 may also receive additional inputs (not shown) from other sensors or components of engine 12, such as an engine shutdown signal, and / or signals from sensors indicating one or more engine operating conditions. Controller 104 also includes a lubricant dilution detection module 108. Lubricant dilution detection module 108 may receive input 102, implement a method 300 for detecting lubricant dilution in lubrication system 14, and control output 106, as referenced below. Figure 3 As stated above.

[0020] The controller 104 may be embodied as a single microprocessor or multiple microprocessors, and may include means for detecting lubricant dilution in the lubrication system 14. For example, the controller 104 may include memory, auxiliary storage, and a processor, such as a central processing unit or any other means for performing tasks consistent with this disclosure. The memory or auxiliary storage associated with the controller 104 may store information that may assist the controller 104 in performing its functions (e.g., ...). Figure 3 The controller 104 may contain data and / or software routines (the functions of method 300). Furthermore, a memory or auxiliary storage device associated with the controller 104 may store data received from various inputs 102 associated with the lubricant dilution detection system 100. Many commercially available microprocessors can be configured to perform the functions of the controller 104. It should be understood that the controller 104 can be readily embodied as a general-purpose machine controller capable of controlling many other machine functions. Furthermore, the controller 104 or portions thereof may be located remotely from the engine system 10. Various other known circuits may be associated with the controller 104, including signal conditioning circuits, communication circuits, hydraulic or other actuation circuits, and other suitable circuits.

[0021] Controller 104 may also include stored values ​​for use by module 108. For example, stored values ​​may include a shutdown event threshold and a lubricant dilution threshold. The shutdown event threshold may include one or more thresholds for various operating conditions of engine system 10 (e.g., engine speed, fuel pump flow rate, intake air, etc.) that indicate a shutdown event of engine system 10, and thus, a shutdown event of lubrication system 14. For example, a shutdown event threshold may include an engine speed threshold (e.g., 850 RPM). When one or more operating conditions (e.g., engine speed) decrease below the corresponding shutdown event threshold, controller 104 may determine that lubrication system 14 (e.g., engine 12) is shutting down. Shutdown may be commanded by the operator of engine 12 (e.g., via an engine shutdown event) and / or may be commanded by controller 104 (e.g., by one or more operating conditions exceeding a threshold).

[0022] The lubricant dilution threshold may include one or more thresholds for indicating lubricant dilution in the lubrication system 14. For example, the lubricant dilution threshold may include one or more lubricant dilution pressure thresholds. One or more lubricant dilution pressure thresholds may include variable thresholds as a function of engine speed during a shutdown event (e.g., ...). Figure 4A and 4B (As shown in threshold 410). For example, one or more lubricant dilution pressure thresholds may include different pressure thresholds for different engine speeds during a shutdown event, provided in a mapping or lookup table. The information used to derive the values ​​of the mapping or lookup table can be determined through empirical analysis. Such empirical data can be obtained, for example, by operating the test engine system 10 under predetermined conditions (e.g., under specific operating conditions) during bench testing. For example, the thresholds may be correlated with values ​​of engine operating conditions (e.g., engine speed). It should be understood that the mapping or lookup table can provide values ​​of lubricant dilution pressure thresholds as a function of any type of input, such as other operating conditions (e.g., values ​​indicating lubricant temperature), as needed.

[0023] The lubricant dilution threshold may also include a range of various operating conditions during a downtime event, used to limit the data points used in measurements compared to the threshold. For example, the range may include an engine speed range (e.g., 250-850 RPM), a lubricant pressure range (e.g., 50-600 kPa), and / or a lubricant (e.g., or coolant) temperature range (e.g., 65-105°C or 80-95°C). Therefore, any measured data points of lubricant pressure during periods when the corresponding operating conditions (e.g., engine speed, lubricant pressure, lubricant temperature) fall outside the corresponding range can be ignored, allowing noise in the data to be filtered out. Furthermore, it should be understood that the ranges provided are merely exemplary, and the engine speed range, lubricant pressure range, and / or lubricant temperature range may include any other ranges required for the respective application.

[0024] The lubricant dilution indication signal 120 may include control over aspects of the engine system 10. For example, the lubricant dilution indication signal 120 may include a controller 104 output signal to display a value indicating lubricant dilution in the lubrication system 14 on an output indicator 16 (e.g., on a display). The lubricant dilution indication signal 120 may also include an alarm output by the controller 104 in the presence of lubricant dilution, such as a visual, audible, or display alarm. The lubricant dilution indication signal 120 may also include mitigation or remediation recommendations. For example, module 108 may recommend maintenance intervals, lubrication system tests, fuel system tests, and / or any other maintenance techniques for locating, mitigating, and / or remediating the causes of lubricant dilution. The lubricant dilution indication signal 120 may also include the controller 104 regulating the engine system 10. For example, the controller 104 may de-delegate or shut down the engine system 10 or a portion thereof.

[0025] Industrial applicability

[0026] The disclosed aspects of the lubricant dilution detection system 100 can be used in any lubrication system 14 that supplies pressurized lubricant.

[0027] refer to Figure 1During operation of engine system 10, engine 12 can drive pump 20, causing pump 20 to draw lubricant from lubricant supply device 18. Pump 20 then supplies pressurized lubricant exiting pump 20 to components of engine 12 via supply line 24, thereby lubricating the components of engine 12. For example, as engine speed increases, pump 20 speed can increase, causing lubricant pressure to increase. During operation of engine system 10, pressurized lubricant in supply line 24 can be regulated at predetermined pressures via valve 26 at certain engine speeds, as detailed above. For example, when engine speed increases beyond a predetermined value, valve 26 can open proportionally, ensuring lubricant pressure does not exceed a predetermined pressure value (e.g., 600 kPa). In some cases, lubricant may become diluted, causing its viscosity to decrease for various reasons, as detailed above. For example, coolant from the lubricant cooler of lubrication system 14 and / or fuel (e.g., diesel) from one or more fuel injectors of the fuel system of engine 12 may leak into lubricant supply device 18. Coolant and / or fuel may have a lower viscosity than lubricant, resulting in a lubricant-coolant / fuel mixture with a viscosity lower than that of the lubricant itself. When the lubricant is diluted, components of engine 12 may be damaged due to reduced lubrication capacity. Furthermore, because valve 26 regulates lubricant pressure at relatively high engine speeds, lubricant dilution may be difficult to detect when valve 26 is open. For example, even if the lubricant is diluted, the lubricant pressure may reach a predetermined value to open valve 26. Therefore, lubricant dilution may not be adequately detected at relatively high engine speeds when valve 26 is open. Additionally, in some types of engine systems, valve 26 may not close when the engine is operating (e.g., during idling). Therefore, refer to the following... Figure 3 In detail, the lubricant dilution detection system 100 can detect lubricant dilution during a shutdown event of the engine system 10 when valve 26 is closed (e.g., at an engine speed of less than 850 RPM).

[0028] Figure 3A flowchart is shown illustrating an exemplary method 300 for detecting lubricant dilution in lubrication system 14. In step 305, module 108 may detect a shutdown event of lubrication system 14 (e.g., shutdown of engine system 10). For example, module 108 may receive a shutdown signal (e.g., engine shutdown or command from controller 104) and / or may otherwise measure engine speed and determine that the engine speed is decreasing below a predetermined shutdown threshold. As detailed above, module 108 may utilize other operating condition parameters and corresponding shutdown event thresholds (e.g., engine speed, fuel pump flow rate, intake air, etc.). Based on determining that the corresponding operating condition has decreased below the corresponding shutdown event threshold, module 108 may determine a shutdown event of lubrication system 14. It should be understood that module 108 may detect a shutdown event of lubrication system 14 by any other method known in the art.

[0029] In step 310, when module 108 detects a shutdown event of lubrication system 14, module 108 can measure the lubricant pressure of lubrication system 14 during the shutdown event. For example, controller 104 can receive lubricant pressure signal 110 and determine or otherwise derive the lubricant pressure of lubrication system 14. Module 108 can also determine the rate of change of lubricant pressure over time based on lubricant pressure signal 110. Furthermore, eventually when lubrication system 14 completely shuts down (e.g., when the shutdown event completes), the lubricant pressure will approach and decrease to zero. Therefore, when the engine speed is within the engine speed range (e.g., between 250-850 RPM), module 108 can limit the measurement window of method 300, as detailed above.

[0030] In step 315, module 108 can determine whether the measured lubricant pressure is less than a threshold (e.g., a lubricant dilution threshold based on operating conditions, as detailed above). For example, when there is no dilution or the dilution is negligible, and the lubrication system 14 is shut down, the lubricant pressure will be higher than the corresponding lubricant dilution threshold for the corresponding operating conditions (e.g., engine speed). Therefore, when the measured lubricant pressure is greater than or equal to the threshold (step 315: No), module 108 can repeat method 300 and continue to detect shutdown events (step 305).

[0031] When the lubricant is diluted, the lubricant pressure can decrease to below a corresponding lubricant dilution threshold during shutdown. Therefore, in step 320, based on determining that the measured lubricant pressure is less than the threshold (step 315: Yes), module 108 can output an indication of lubricant dilution. For example, module 108 can display the lubricant dilution indication on output indicator 16 (e.g., on a display and / or as a notification, such as a light, audible alarm, display alarm, etc.). Module 108 can then repeat method 300 and continue detecting shutdown events (step 305). Furthermore, module 108 can store the lubricant dilution indication (e.g., as a flag) so that module 108 can indicate lubricant dilution when lubrication system 14 is restarted. Module 108 can also generate recommendations for mitigating lubricant dilution and output these recommendations (e.g., via output indicator 16).

[0032] In some embodiments, module 108 may store values ​​or instances of lubricant pressure measured during multiple shutdown events. For example, module 108 may detect several different shutdown events and store the measured lubricant pressure values. (See reference...) Figure 4A and 4B Module 108 can generate graphs 400a and 400b of the measured lubricant pressure over time for different shutdown events. For example, Figure 4A A graph 400a showing lubricant pressure versus engine speed during downtime, according to the first embodiment, is provided. Similarly, Figure 4B A graph 400b showing lubricant pressure versus engine speed during downtime, according to a second embodiment, is provided. Graphs 400a and 400b may include a graphical representation of various data points 405a and 405b of measured lubricant pressure for various engine speeds. Furthermore, dashed lines indicate lubricant dilution thresholds 410 for various engine speeds. Figure 4A As shown, when the engine speed decreases during a shutdown event (e.g., engine speed is less than 850 RPM, as indicated by...), Figure 4A When the vertical dashed line is shown in the figure, the lubricant dilution threshold 410 can be substantially linear. However, in embodiments where pump 20 is driven by engine 12 (e.g., crankshaft), there is a second-order relationship between the lubricant pressure exiting pump 20 and engine speed. For example, there may be a delay between the decrease in engine speed and the decrease in pump 20 speed, thus causing a delay in the decrease in lubricant pressure as engine speed decreases. Therefore, the relationship between lubricant pressure and engine speed may not be perfectly linear. Therefore, as... Figure 4BAs shown, the lubricant dilution threshold 410 is not perfectly linear as engine speed decreases. For example, threshold 410 could be exponential, or it could include another type of relationship between lubricant pressure and engine speed. Therefore, lubricant dilution may occur when one or more data points 405b drop below the corresponding lubricant dilution threshold 410 for the corresponding engine speed during a shutdown. As detailed above, it should be understood that graphs 400a, 400b could include lubricant pressure versus other operating conditions besides engine speed, such as lubricant temperature or any other operating condition.

[0033] Furthermore, to reduce or eliminate erroneous triggering of lubricant dilution detection, module 108 may include one or more predetermined ranges for various operating conditions. For example, module 108 may consider data points 405a, 405b for measured lubricant pressure when the value indicating engine speed is between 250-850 RPM, the value indicating lubricant temperature (e.g., as measured from lubricant temperature signal 114) is between 65-105°C (or 80-95°C), and / or the value indicating lubricant pressure is between 50-600 kPa. Therefore, when the corresponding operating conditions are outside the corresponding ranges, module 108 may ignore or otherwise eliminate the measured lubricant pressure data points. To further reduce or eliminate erroneous triggering of lubricant dilution detection, module 108 may also include de-jittering conditions. For example, de-jittering conditions may include a predetermined threshold for the amount of time (e.g., 3 seconds) during which the measured lubricant pressure is less than a lubricant dilution threshold. Similarly, module 108 may also include an amount of data points 405b that need to be less than a lubricant dilution threshold as a function of the total amount of data points 405a, 405b. For example, if 3 out of 15 data points are below the lubricant dilution threshold, module 108 can determine lubricant dilution.

[0034] The lubricant dilution detection system 100 can provide an indication of lubricant dilution in the lubrication system 14. For example, the lubricant dilution detection system 100 can detect lubricant dilution caused by, for example, fuel leaks in the fuel system of engine 12, coolant leaks from the lubricant cooler, lubricant aging, and / or any other dilution cause. Furthermore, by detecting lubricant dilution during downtime events, the lubricant dilution detection system 100 can ensure that valve 26 is closed, allowing the system 100 to detect lubricant dilution more fully. Therefore, the lubricant dilution detection system 100 can more accurately or fully detect lubricant dilution in the lubrication system 14 and proactively alert users (e.g., operators, technicians, etc.) so that they can repair and / or replace the corresponding components to mitigate lubricant dilution.

[0035] Various modifications and alterations can be made to the disclosed system without departing from the scope of this disclosure, as will be apparent to those skilled in the art. Other embodiments of the system will become apparent to those skilled in the art upon consideration of the description and practice of the system disclosed herein. The specification and examples are intended to be considered exemplary only, and the true scope of this disclosure is defined by the following claims and their equivalents.

Claims

1. A method for detecting lubricant dilution in a lubrication system (14), comprising: Detect shutdown events of the lubrication system (14); Lubricant pressure was measured during the shutdown event; Lubricant dilution is determined based on the lubricant pressure measured during the downtime event; as well as Based on the determination that lubricant dilution exists, an indication of lubricant dilution is output; Determining lubricant dilution includes: Compare the measured lubricant pressure with the lubricant dilution pressure threshold; Determine whether the measured lubricant pressure is less than the lubricant dilution pressure threshold; and Lubricant dilution is determined by determining that the measured lubricant pressure is less than the lubricant dilution pressure threshold, wherein the lubricant dilution pressure threshold is a variable threshold based on the engine speed during a shutdown event.

2. The method of claim 1, wherein detecting the shutdown event includes detecting an engine shutdown signal or a shutdown command signal.

3. The method of claim 1 or 2, wherein detecting the shutdown event includes detecting that the engine speed decreases below a speed threshold.

4. The method according to claim 1 or 2, further comprising: Lubricant dilution is determined based on lubricant pressure measured during multiple downtime events.

5. The method according to claim 1, further comprising: Lubricant dilution is determined when the measured lubricant pressure is less than the lubricant dilution pressure threshold for a predetermined time.

6. The method according to any one of claims 1, 2 and 5, further comprising determining lubricant dilution based on lubricant pressure measured during the shutdown event when the value indicating the lubricant temperature is between 65 and 105°C.

7. The method according to any one of claims 1, 2, and 5, wherein outputting the indication of lubricant dilution comprises: Generate recommendations for mitigating lubricant dilution; as well as Output the recommendations.

8. A lubricant dilution detection system (100), comprising: Lubrication system (14); Sensor (32), the sensor being used to measure the lubricant pressure in the lubrication system (14); as well as Controller (104), the controller is configured to: Detect shutdown events of the lubrication system (14); Lubricant pressure was measured during the shutdown event; Lubricant dilution is determined based on the lubricant pressure measured during the downtime event; as well as Based on the determination that lubricant dilution exists, an indication of lubricant dilution is output; Determining lubricant dilution includes: Compare the measured lubricant pressure with the lubricant dilution pressure threshold; Determine whether the measured lubricant pressure is less than the lubricant dilution pressure threshold; and Lubricant dilution is determined by determining that the measured lubricant pressure is less than the lubricant dilution pressure threshold, wherein the lubricant dilution pressure threshold is a variable threshold based on the engine speed during a shutdown event.

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