KR20110123669A - Improved monitoring of wear of bearing in a large two stroke diesel engine - Google Patents

Abstract

PURPOSE: Improved monitoring of wear of bearing in a large two-stroke diesel engine is provided to determine wear of a main bearing, a crankpin bearing and a crosshead bearing using two sensors and generate alarm if failure is imminent. CONSTITUTION: Improved monitoring of wear of bearing in a large two-stroke diesel engine comprises at least two sensors and a controller. The controller receives signals from each sensor(410). The controller compensates each signal depending on the operation conditions of an engine(420). The controller determine the excess of a critical value and if yes, the critical value is indicated(460). The controller generates a compensating table for the operation conditions of an engine during operation of the engine under learning by sampling the number of first sensor values to the number of second engine operation condition points during operation of the engine.

Description

Improved monitoring of wear of bearing in a large two stroke diesel engine

The present application relates to an apparatus and method for measuring bearing wear in large two-stroke diesel engines.

The main bearings, crankpin bearings and crosshead bearings of large two-stroke diesel engines have bearing shells at the top and bottom that form bearing surfaces for supporting corresponding bearing journals. The bearing barrels have a steel back with a bearing metal layer on top. The bearing metal is typically a tin-aluminum alloy or white metal alloy, which is a layer approximately 1.5 to 2 mm thick.

Despite much attention in the manufacture and operation of these engines, small failure rates exist. Since most large two-stroke diesel engines are marine vessels, engine failure due to bad bearings is very undesirable.

Moreover, the cost of overhauling the bearings can most often require, for example, regrinding of the crankshaft, which can substantially lead to engine downtime.

Classification societies require inspections to be carried out every four or five years in accordance with the classification so as to prevent such occurrences from occurring, during which the bearings are disassembled and inspected.

This inspection is rather complicated and requires disassembly of the bearings and reassembly of the bearings. This process involves the risk of substantial build errors, ie, errors introduced during the overhaul.

To alleviate the need for inspection, the prior art proposes to monitor bearing wear by measuring the distance of bearing wear.

US patent application US 2007/0017280 discloses measuring the position of a guide shoe of a crosshead by using two sensors for each cylinder. This enables detection of wear in the main bearings, crankpin bearings and crosshead bearings, and can also determine whether the wear is in the main bearings or crankpin bearings and crosshead bearings. These measurements are used to determine whether wear leads to failure and to generate a warning if the failure is imminent.

As noted above, the consequences of failure can be serious, so an efficient and accurate way of detecting wear of a bearing is very useful.

Summary of the Invention

In this context, there is provided an apparatus and method for improving the efficiency and accuracy of prior art systems by providing a method and apparatus designed to calibrate and / or interpret the reading of the sensor in an improved manner. Would be advantageous.

The first purpose for monitoring the wear of the bearing is to detect the bearing failure before the bearing failure develops to the extent that thermal damage is caused in other parts than the bearing lining. The parts that may be affected are bearing housings due to crossheads, crank-pins, vane bearing journals or distortions. If the bearing lining is worn and a contact is made between the shaft and the steel back of the bearing barrel, such damage will generally result.

Although the description below focuses on compensating engine speed, it should be noted that what is taught here also applies to compensation for propeller pitch level and load. These are examples of engine operating conditions that affect the bottom dead center of the movable part, such as some crossheads or guide shoes in the engine.

The disclosed embodiment provides an apparatus for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a large two-stroke diesel engine, the apparatus comprising at least two sensors, the sensors fixing the engine Arranged and configured to measure a bottom dead center for a crosshead or guide shoe of a given cylinder relative to a point, the apparatus further comprising a controller, the controller comprising: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; Determine a deviation in accepting factors affecting the sensor signal; Determine whether the threshold has been exceeded, and if so generate an indication of the exceeded threshold.

In one embodiment, the engine operating condition is engine speed.

In one embodiment, the engine operating condition is a propeller pitch level.

In one embodiment, the engine operating condition is a load.

By determining the deviation of the sensor signal, the controller can accept external influences that can affect one or more sensors or otherwise be interpreted as a change in the BDC level.

Aspects of the disclosed embodiments also provide a method of executing a device having a controller configured to perform instructions stored on a physical medium, the method of execution of crosshead bearings, crankpin bearings and main bearings of a large two-stroke diesel engine. Wherein the device comprises at least two sensors, the sensors arranged and configured to measure the bottom dead center for a crosshead or guide shoe in a given cylinder relative to a fixed point of the engine. Is: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; Determining a deviation in accommodating factors influencing the sensor signal; Determining whether the threshold has been exceeded, and if so generating an indication of the exceeded threshold.

Aspects of the disclosed embodiments also provide an apparatus for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a large two-stroke diesel engine, the apparatus comprising at least two sensors, the sensors comprising an engine Disposed and configured to measure a bottom dead center for a crosshead or guide shoe of a given cylinder relative to a fixed point of the device, the apparatus further comprising a controller, the controller comprising: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; Determine whether the threshold has been exceeded, and if so generate an indication of the exceeded threshold, wherein the controller is further configured to dynamically change the threshold in accordance with the current operation of the engine.

Aspects of the disclosed embodiments also provide a method of executing a device having a controller configured to perform instructions stored on a physical medium, the method of execution of crosshead bearings, crankpin bearings and main bearings of a large two-stroke diesel engine. For monitoring wear, the apparatus comprising at least two sensors, the sensors being arranged and configured to measure the bottom dead center for the crosshead of a given cylinder with respect to a fixed point of the engine, the method of implementation being: Receiving a signal from a sensor of the sensor; Compensating each signal according to the engine operating condition; Determining whether the threshold has been exceeded, and if so generating an indication of the exceeded threshold, the method of execution further comprising dynamically changing the threshold in accordance with the current operation of the engine.

Aspects of the disclosed embodiments also provide an apparatus for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a large two-stroke diesel engine, the apparatus comprising at least two sensors, the sensors comprising an engine Arranged and configured to measure the bottom dead center for a crosshead or guide shoe in a given cylinder for a fixed point of the at least two sensors, one in each cylinder one forward sensor and one rear sensor, Further comprises a controller, the controller: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; Determine whether the threshold has been exceeded, and if so create an indication of the exceeded threshold, the controller bearing by combining the signal of the front sensor of the first cylinder with the signal of the second sensor of the second cylinder. Determine whether it is worn, and / or combine the signal of the front sensor of the first cylinder with the signal of the second sensor of the second cylinder and combine the two sensor signals to compare the result of the two sensor signals to a threshold level. Thereby further determining whether the bearing is worn.

Aspects of the disclosed embodiments also provide a method of executing a device having a controller configured to perform instructions stored on a physical medium, the method of execution of crosshead bearings, crankpin bearings and main bearings of a large two-stroke diesel engine. Wherein the device comprises at least two sensors, the sensors arranged and configured to measure the bottom dead center for a crosshead or guide shoe in a given cylinder relative to a fixed point of the engine. Is: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; Determining whether the threshold has been exceeded, and if so generating an indication of the exceeded threshold, the method of execution combining the signal of the front sensor of the first cylinder with the signal of the latter sensor of the second cylinder. Thereby determining whether the bearing is worn or in critical condition, and / or combining the signal of the front sensor of the first cylinder with the signal of the second sensor of the second cylinder, and combining the two sensor signals, Comparing the result of the signals to a threshold level to determine whether the bearing is worn or in a critical condition.

Aspects of the disclosed embodiments also provide an apparatus for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a large two-stroke diesel engine, the apparatus comprising at least two sensors, the sensors comprising an engine Disposed and configured to measure a bottom dead center for a crosshead or guide shoe in a given cylinder for a fixed point of the apparatus, the apparatus further comprising a controller, the controller comprising: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; Determine whether the threshold has been exceeded, and if so generate an indication of the exceeded threshold, wherein the controller compares the received sensor signals with the average level of the signal values for a previous period of time Is further configured to detect a change.

Aspects of the disclosed embodiments also provide an apparatus for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a large two-stroke diesel engine, the apparatus comprising at least two sensors, the sensors comprising an engine Disposed and configured to measure a bottom dead center for a crosshead or guide shoe in a given cylinder for a fixed point of the apparatus, the apparatus further comprising a controller, the controller comprising: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; Determine whether the threshold has been exceeded, and if so, generate an indication of the exceeded threshold, wherein the controller updates the reference level for the sensor, updates the current level for the sensor, It is further configured to detect a sudden change in the bottom dead center level by determining whether a sudden change in the threshold level has been exceeded.

Aspects of the disclosed embodiments also provide a method for monitoring wear of crosshead bearings, crankpin bearings and main bearings in large two-stroke diesel engines, the apparatus comprising at least two sensors, the sensors comprising an engine Disposed and configured to measure a bottom dead center for a crosshead or guide shoe in a given cylinder for a fixed point of the apparatus, the apparatus further comprising a controller, the controller comprising: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; Determine whether the threshold has been exceeded, and if so, generate an indication of the exceeded threshold, wherein the controller updates the reference level for the sensor, updates the current level for the sensor, It is further configured to detect a sudden change in the bottom dead center level by determining whether a sudden change in the threshold level has been exceeded.

Aspects of the disclosed embodiments also provide a method of executing a device having a controller configured to perform instructions stored on a physical medium, the method of execution of crosshead bearings, crankpin bearings and main bearings of a large two-stroke diesel engine. Wherein the device comprises at least two sensors, the sensors arranged and configured to measure the bottom dead center for a crosshead or guide shoe in a given cylinder relative to a fixed point of the engine. Is: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; Determining whether the threshold has been exceeded, and if so generating an indication of the exceeded threshold, wherein the method of execution comprises the abrupt increase of the BDC level by comparing the measured sensor values with an average level during the previous period. Detecting the change.

Aspects of the disclosed embodiments also provide an apparatus for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a large two-stroke diesel engine, the apparatus comprising at least two sensors, the sensors comprising an engine Disposed and configured to measure a bottom dead center for a crosshead or guide shoe in a given cylinder for a fixed point of the apparatus, the apparatus further comprising a controller, the controller comprising: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; Determine whether the threshold has been exceeded, and if so generate an indication of the exceeded threshold, wherein the controller is configured to determine the number of first sensor values to the number of second speed points during operation of the engine. Generate an engine speed compensation table during operation of the engine in the learning phase by sampling against and set a reference value by averaging received sample values for the speed point when the number of first samples is received for the speed point. It is composed.

Aspects of the disclosed embodiments also provide a method of executing a device having a controller configured to perform instructions stored on a physical medium, the method of execution of crosshead bearings, crankpin bearings and main bearings of a large two-stroke diesel engine. Wherein the device comprises at least two sensors, the sensors arranged and configured to measure the bottom dead center for a crosshead or guide shoe in a given cylinder relative to a fixed point of the engine. Is: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; Determining whether the threshold has been exceeded, and if so generating an indication of the exceeded threshold, the method of execution comprising: determining the number of first sensor values during operation of the engine at a second speed point; Generating an engine operating condition compensation table during operation of the engine in learning phase by sampling for the number of times and averaging the received sample values for the speed point when the number of first samples is received for the speed point. The method further includes setting a value.

Aspects of the disclosed embodiments also provide an apparatus for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a large two-stroke diesel engine, the apparatus comprising at least two sensors, the sensors comprising an engine Disposed and configured to measure a bottom dead center for a crosshead or guide shoe in a given cylinder for a fixed point of the apparatus, the apparatus further comprising a controller, the controller comprising: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; Determine whether the threshold has been exceeded, and if so generate an indication of the exceeded threshold, wherein the controller calculates an average of the offsets for the sensors that have been readjusted or replaced over a period of time. Recondition the reconditioned or replaced sensor by adjusting the signals from the readjusted or replaced sensor by compensating the signal value according to the compensatory lookup table, and offset the reference values for the affected sensor according to the calculated average offset. Is further configured.

Aspects of the disclosed embodiments also provide a method of executing a device having a controller configured to perform instructions stored on a physical medium, the method of execution of crosshead bearings, crankpin bearings and main bearings of a large two-stroke diesel engine. Wherein the device comprises at least two sensors, the sensors arranged and configured to measure the bottom dead center for a crosshead or guide shoe in a given cylinder relative to a fixed point of the engine. Is: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; Determining whether the threshold has been exceeded, and if so, generating an indication of the exceeded threshold, the method of execution comprising calculating an average of the offsets for the sensors that have been readjusted or replaced over a period of time; Reconditioning the reconditioned or replaced sensor by adjusting the signals from the readjusted or replaced sensor by compensating the signal value according to the engine operating condition compensation compendium and the reference value for the affected sensor according to the calculated average offset Offsetting them.

Aspects of the disclosed embodiments also provide an apparatus for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a large two-stroke diesel engine, the apparatus comprising at least two sensors, the sensors comprising an engine Disposed and configured to measure a bottom dead center for a crosshead or guide shoe in a given cylinder for a fixed point of the apparatus, the apparatus further comprising a controller, the controller comprising: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; And determine if the threshold has been exceeded, and if so create an indication of the exceeded threshold, wherein the controller is further configured to generate trend curves indicating whether any wear has occurred for a period of time.

Aspects of the disclosed embodiments also provide a method of executing a device having a controller configured to perform instructions stored on a physical medium, the method of execution of crosshead bearings, crankpin bearings and main bearings of a large two-stroke diesel engine. Wherein the device comprises at least two sensors, the sensors arranged and configured to measure the bottom dead center for a crosshead or guide shoe in a given cylinder relative to a fixed point of the engine. Is: receiving a signal from each sensor; Compensating each signal according to the engine operating condition; Determining whether the threshold has been exceeded, and if so generating an indication of the exceeded threshold, the method of execution further comprising generating trend curves indicating whether any wear has occurred during a period of time. Include.

An aspect of the disclosed embodiments is also to provide an engine comprising any device as described above.

The disclosed embodiment also provides a marine vessel comprising an engine as described above.

The disclosed embodiment also provides a computer readable medium comprising at least computer program code for monitoring the wear of a bearing of a large two-stroke diesel engine, the computer readable medium comprising any one or a plurality of the foregoing. It includes software code for executing the method.

Other objects, features, advantages and characteristics of the apparatus, method and computer readable medium according to the present application will become apparent from the detailed description.

In the following detailed description of the invention, the teachings of this application will be described in more detail with reference to the embodiments shown in the drawings.
1 is a schematic diagram of an engine according to one embodiment.
2 is a schematic view of a bearing according to one embodiment.
3 is a flow chart illustrating an overall method according to one embodiment.
4 is a flowchart illustrating a method according to an embodiment.
5 is a flowchart illustrating a method according to an embodiment.
6 is a diagram illustrating a curve according to an embodiment.
7 is a diagram illustrating a curve according to an embodiment.
8 is a flowchart illustrating a method according to an embodiment.
9 is a flowchart illustrating a method according to an embodiment.
10 is a diagram illustrating a curve according to an embodiment.

In the following detailed description, devices, methods, and software products in accordance with the teachings of the present application will be described by embodiments for opposing two-stroke diesel engines. Although only two-stroke engines are described, it should be noted that the teachings of the present application can be used with any engine, such as four-stroke engines, two-stroke gasoline engines and small two-stroke diesel engines.

1 is a cross-sectional view of the engine 100. The engine has a crankshaft with a main journal 100 and one or more crank pins 120, with each crosshead 130 connected to the crank pins.

There are at least three bearings for each cylinder, which are the main bearing 140 (not shown in FIG. 1 shown in dashed line), the crank pin bearing 150 and the crosshead bearing 160.

Two sensors 170 (only one shown) are disposed for each cylinder. In one embodiment, one sensor 170 is disposed behind the crosshead 130 and one sensor 170 is disposed in front of the crosshead 130. The sensors 170 are arranged to measure the distance between the crosshead 130 and the fixation point. As an alternative, the sensors are arranged to measure the distance between the point of attachment to the crosshead and the fixation point.

As an alternative, the sensors are arranged to measure the distance to the guide shoe 135.

In FIG. 1, the sensor 170 is disposed on the engine structure 100 and measures the distance to the reflective plate 175 attached to the guide shoe 135. It should be noted that different alternatives exist for what kind of sensor is used, how it is arranged, and what distance is measured.

In a preferred embodiment, the sensor 170 is placed on the engine structure to produce the most reliable reading when the sensor remains stationary.

In one embodiment, the sensor plate 175 is disposed on the crosshead pin to ensure reading while reducing variations due to angular motion of the guide shoe 135.

In one embodiment, the sensors are inferior to a structure in the engine that moves with or is attached to the crosshead (eg, a guide shoe as described above, but other structures are possible). It is arranged to determine the bottom dead center (BDC) level, where an indirect reading of the bottom dead center of the crosshead is determined. Thus, the measurement of the bottom dead center for such a structure allows determination of variations and deviations in the BDC level for the crosshead.

As an alternative, the sensors 170 may be disposed differently, and the sensors may be disposed at positions that are not linear with the shaft. However, if possible, it can be arranged parallel to the shaft. In addition, the sensors are preferably arranged axially spaced along the parallel to the shaft, as this allows determination of whether there is wear in the main bearing 140.

The sensors are thus configured to provide a measurement of the lowest point level, ie, bottom dead center, for the crosshead 130 during one revolution of the engine 100.

As will be apparent to those skilled in the art, there are a number of alternatives for implementing the sensor 170, such as, for example, an optical proximity sensor or a capacitance-measuring proximity sensor.

FIG. 2 shows the general structure of a bearing 200 having a core 210 of hard metal such as steel and a lining wall 220 of a soft metal such as white metal or tin-aluminum.

The thickness of the lining is typically in the range of 1.0 to 1.5 mm, and the sensors 170 are designed to repeatedly measure the level or distance with an accuracy of +/- 0.01 mm.

The controller is coupled to the sensors 170 and is configured to receive measurements from the sensors 170 and process the measurements to measure wear of the bearings. In one of the bearings 140, 150, 160, any change in the thickness of the bearing wall 220 of the loaded portion (due to wear or seizure) may cause one or more crossheads to the structure of the engine 100. Based on the fact that it will result in a corresponding change in the bottom dead center (BDC) level of the 130, the wear measurement is made. In the case of crank pin 150 or crosshead bearing 160 wear, the BDC of the cylinder in question will change, whereas in the case of main bearing 140 wear, one sensor 170 in one cylinder ) And the BDC level of one sensor in the adjacent cylinder will change.

The signal from the sensors 170 will contain some level of noise, which will affect the accuracy of the readings of the sensors.

Another factor that will affect the accuracy of the sensors is that the BDC level of the actual guide shoe or crosshead will change slightly due to small irregularities in engine parameters such as firing pressure and the like.

One other factor influencing the signal is the engine speed, ie the revolutions per minute (rpm) of engine 100.

One other factor that affects the signal is the propeller pitch level.

One other factor that affects the signal is the load the engine receives. One example of such a load is the load of cargo carried by a ship.

These are all examples of engine operating conditions, and although the following description is focused on compensating engine speeds, the teachings of the present invention may be applied alone or in combination to compensate other operating conditions.

Other factors, such as hull deformation from different ship drafts and engine temperatures, may have some effect on BDC levels, such as changes in the manufacturing of various engine parts.

Factors such as signal scattering of the bearing may also affect the measured BDC level.

The methods and apparatus disclosed herein are configured to provide a reliable measure in bearing wear of an engine in view of such factors and other factors.

3 shows a flow chart for a general method of embodiments herein.

In a first step 310 a signal from the sensors 170 is obtained by the controller. The signals are then modified and processed by compensating for various factors and calculating the deviation (320), and the results are evaluated (330), where it is determined whether a warning should be given.

There are many factors that affect bearing wear in the engine during operation. If the engine fails, it is important to isolate the source of the failure. In the case of bearing wear, it is important to understand the cause of the bearing wear increase, otherwise new bearings will wear out faster than expected.

As previously known and mentioned above, using two sensors for each cylinder allows the operator to separate the position of the bearing being worn. Identifying which bearing needs to be replaced helps to replace it, because engineers know where to open the engine, and do not have to do the unnecessary work of finding which bearing.

However, as the inventors of the present application understood, further information can be extracted from these two sensor readings as to which information is useful for identifying the cause of the (increased) wear, which the engineer solves the problem. And increased wear on the replacement bearings.

Further information may be used to accept situations where some or all of the sensors are affected without any damage present.

As shown below, the extracted information can be used to provide an early warning before the bearing wears, to help the operator heal the cause of the warning and prevent the bearings from wearing out, thus causing engine failure and consequent engine failure. Downtime can be prevented.

The apparatus and method of the present invention are thus very advantageous because it is possible to identify the cause of the increased wear, predict failures and perform without additional sensors.

Thus, the system can be easily integrated into existing engines with two sensors installed by connecting with an upgraded controller or possibly by updating an existing controller.

The most significant effect on the BDC level is the engine speed, and the signal value received from the sensor (s) should be compensated for the engine speed, or the BDC level will be lower as the engine speed is increased, and wear monitoring indicates that the bearings are worn. Will signal wrong.

Depending on the engine speed used, there may be a change of 0.3 mm or more in the BDC level depending on the engine size. Therefore, compensation for such effects is needed. Since the influence is individual for each facility, depending on the alignment and arrangement of the shaft line, etc., the compensation for each sensor must be set individually for each facility.

The signal value is compensated for engine speed through the use of a look up table with the BDC levels of each sensor over a wide speed range.

In one embodiment, the controller is configured to compensate for the speed based on a lookup table comprising normal or average signal values dependent on engine speed or rpm (reference value).

The normal value can vary significantly in small changes in engine speed.

In one embodiment, the lookup table has a resolution corresponding to dividing the speed range of standard engine speed into sub ranges, which is hereinafter referred to as speed point.

In one embodiment, the speed range corresponds to a range of 0% to 120% of standard engine speed.

In one embodiment, the speed range corresponds to a range of 20% to 110% of standard engine speed.

In one embodiment, a range of less than 20% of standard engine speed is not taken into account in monitoring the wear of the bearings.

In one embodiment, the controller is configured to consider whether the engine is reversing.

Due to the speed compensation, the measurement considered by the controller is not the actual BDC level, but it is the difference between the measured BDC level and the average BDC level at the current engine speed. This makes it possible to detect abnormal or unexpected changes in BDC levels due to wear of the bearings.

Thus the processing of the signal received from the sensor should be based on the value compensated for the signal.

In one embodiment, the controller is configured to determine the compensation signal value by subtracting the reference value from the received signal value:

S _comp = S _N -S _ref

In one embodiment, the controller is configured to filter sensor values.

To minimize the impact of noise, the values provided by the sensors 170 are filtered using a low pass filter in one embodiment.

In one embodiment, a simple filter is used, in which the moving average is updated for each sensor value, ie, once for each engine revolution. In one embodiment, the filter is represented as follows:

New filter value = old filter value * (1-x) + value * x

The value of x affects how quickly the controller responds to changes. High values make the controller very sensitive to change and therefore noise sensitive, while low values of x will cause a slow response to real events. In one embodiment, X is 0.05.

Some factors affect all sensors in common, and signals received from the affected sensors may be interpreted incorrectly.

One such factor is the changed engine temperature.

To distinguish between such changes and changes due to increased wear of the bearings, a deviation for each sensor value is calculated.

In one embodiment, the controller is configured to calculate the deviation of the signal of the sensors by comparing the values of the other sensors by subtracting the average of the other signals from the individual signal.

The sensor deviation d (S ₁ ) for sensor ₅ (S ₅ ) from the full set of _eight sensors S ₁ to S ₈ (corresponding to a four cylinder engine) can be expressed as have:

d (S ₅ ) = S _5- (S ₁ + S ₂ + S ₃ + S ₄ + S ₆ + S ₇ + S ₈ ) / 7

One other factor is the effect of deformation formed by the longitudinal shear of the engine structure, which is sometimes caused by a change in thrust. In some cases, this deformation causes the front and rear sensors in the cylinder to show changes with respect to each other.

The conclusions from careful monitoring and investigation of the engine during engine operation and careful analysis of the findings indicate that the variation for the two sensors indicates that the signal values are often in the reverse phase. Is the point. This causes the signal value for another sensor to increase when the signal value for one sensor decreases, and vice versa. This is hereinafter referred to as cylinder deviation.

In one embodiment, the controller is configured to remove such a change by measuring an average sensor value for two sensors of one cylinder and compare it to the average value of the sensors of the other cylinders.

The cylinder deviation d (cyl _i ) of the cylinder ₃ (cyl ₃ ) from the whole set of four cylinders with _eight sensors S ₁ to S ₈ can be expressed as follows.

d (cyl ₃ ) = (S ₅ + S ₆ ) / 2-(S ₁ + S ₂ + S ₃ + S ₄ + S ₇ + S ₈ ) / 6

Both cylinder and sensor deviations reduce the effects of signal scattering. However, cylinder deviation is more efficient in reducing signal scattering.

Therefore, calculating cylinder deviation is useful for reducing signal scatter.

For situations where only one sensor detects damage to the bearing, the deviation of the cylinder is less sensitive because the detected change will be halved during the deviation calculation.

Therefore, it is desirable to calculate both cylinder and sensor deviations to allow for reliable detection of bearing damage.

In one embodiment, the controller is configured to calculate both cylinder and sensor deviations.

One example of a situation where one or more sensors are affected is when one or more bearings are damaged. This may be the result of a common corrosion process in which several or all bearings deteriorate. Such a situation may be the result of oil contamination or a failure in oil supply.

Such a situation can be easily detected from cylinder deviation and sensor deviation since the effects can be canceled by the average process of the calculations.

However, such a situation can be detected from the engine speed compensation value for each signal.

In one embodiment, the controller is configured to calculate cylinder deviation, sensor deviation, and engine speed compensation signal values.

In the embodiment according to the above, the controller is configured to extract information from the signal values in consideration of several factors affecting the reliability of the sensor reading.

The controller of the device according to the invention can thus produce reliable readings for monitoring the wear of the engine bearings.

In one embodiment, the controller is configured to determine whether the damage is urgent or about to occur and evaluate the readout.

In one embodiment, the controller is configured to compare the current reading for the cylinder or bearing with the average value taken over a period of time. In one implementation the period is 6 hours. In one embodiment, the controller is configured to determine whether the difference between the current reading and the time average is greater than the threshold level, and if so, to activate the proactive alert action. In one embodiment, the pre-alarm limit is +/- 0.25 mm.

If the pre-alarm level is exceeded, it indicates that the condition of the bearing being monitored is changing.

In one embodiment, the controller is configured to store a pre-alert in a log file.

In one embodiment, the controller is configured to receive an input that resets the pre-alert action.

Since only the condition of the bearings that have started to change is detected, the engine may not be at any risk for at least several hours, thus enabling the engine to continue operation by resetting the pre-alarm action.

In one embodiment, the controller is configured to compare the current reading of the cylinder or bearing to an alarm threshold. If such threshold is exceeded, the controller is configured to activate an alarm.

The alarm indicates that the affected bearings are beginning to wear or are wearing out and must be inspected.

In one embodiment, the alarm threshold for the sensor value is +/− 0.5 mm.

In one embodiment, the alarm threshold for sensor deviation is +/- 0.4 mm.

In one embodiment, the alarm threshold for cylinder deviation is +/- 0.3 mm.

In one embodiment, the controller is configured to store the alarm action in a log file.

If a large change is detected, a request for deceleration of the engine speed may occur. Engine speed has the greatest impact on bearing load and bearing wear, and in some situations slowing the engine speed can prevent or delay engine failure resulting from damaged bearings. In severe cases, the engine will have to be completely stopped to prevent failure.

In one embodiment, the controller is configured to compare the current reading for the cylinder or bearing with a slow-down threshold. If such a threshold is exceeded, the controller is configured to generate a deceleration request. In one embodiment, the threshold for sensor values is +/- 0.7 mm. In one embodiment, the deceleration threshold for sensor deviation is +/− 0.5 mm.

In one embodiment, the controller is configured to automatically slow down the engine speed upon such a deceleration request.

In one embodiment, the controller is configured to automatically stop the engine upon such deceleration requests.

In one embodiment, the controller is configured to store the deceleration request in a log file.

4 illustrates a general method of monitoring wear of a bearing in accordance with an embodiment of the present application.

In one embodiment, the controller is configured to perform the steps of FIG. 4 in parallel for all sensors.

In one embodiment, the controller is configured to perform the steps of FIG. 4 for one cylinder. In one such embodiment, each cylinder has one controller. In one such embodiment, the controller is configured to receive signal values from the controller for other cylinders.

In a first step 410, the value is received or a signal (S _N) by the controller.

In one embodiment, the controller is configured to calculate the compensation value through subtracting the reference value from the received signal (420):

S _comp = S _N -S _ref

In one embodiment, the controller is further configured to apply a filter to reduce noise in the received signal (430).

In one embodiment, the controller is configured to calculate a sensor deviation, d (S _sensor ):

d (S _sensor ) = S _sensor -mean of other sensors

In one embodiment, the controller is configured to calculate the cylinder deviation, d (cylinder):

d (cylinder) = (S _{cylinder , fore} + S _{cylinder , aft} ) / 2-average of other sensors

Both deviations in FIG. 4 are calculated at step 440.

In one embodiment, the controller is configured to determine whether the alarm threshold for the sensor value has been exceeded (450) and if so activate (460) the alarm.

In one embodiment, the controller is configured to determine whether the alarm threshold for sensor deviation has been exceeded (450) and if so activate (460) the alarm.

In one embodiment, the controller is configured to determine whether the alarm threshold for cylinder deviation is exceeded (450) and if so activate (460) the alarm.

In FIG. 4 all three decisions about the alarm limit are performed at 450.

If the controller determines that the alarm should be activated, the controller is further configured to store the event in a log file (460).

In one embodiment, the controller determines whether the deceleration limit for the sensor deviation is exceeded (480) and if so activates the request for the deceleration process (490).

In one embodiment, the controller is configured to return to step 410 for receiving a new signal value.

In one embodiment, the controller is configured to perform steps 410 through 440 for each rotation.

In one embodiment, the controller is configured to perform steps 450 through 490 for each rotation.

In one embodiment, the controller is configured to perform steps 450 to 490 at intervals. In one embodiment, the spacing is in the range of 1 to 50 revolutions. In one embodiment, the interval is 30 turns. This is indicated by the dashed line in FIG. 4.

In one embodiment, the controller is configured to recalculate the average of signal values for each sensor at 50 time intervals at each speed point. This allows the system to adapt and respond to changes in the engine structure.

In one embodiment, it is determined whether the reference value for any engine speed is changed by a value greater than the update critical when compared with a valid compensation value initially obtained, and if so, by activating indicating it. The controller is configured to generate an alarm. In one embodiment, the update threshold is 0.2 mm.

In one embodiment, the controller is configured to dynamically change the threshold for at least one of pre-warning, alarm and deceleration in accordance with the current operation of the engine.

During normal operation of a large two-stroke diesel engine, the engine is set to run at one engine speed for a long time. During this period, the engine's environment is fairly stable. For example, since there is no acceleration, deformation due to thrust does not occur.

When the engine speed changes, the environment becomes less stable, which affects the BDC level of the bearing and the BDC level changes and / or varies accordingly. During such period, the controller is configured to raise the threshold level to accommodate such a change without generating any alarm.

One example of another situation that affects the engine environment or engine operation is when the load on the vessel being propelled by the engine increases and the vessel enters deep into the water.

The controller is configured to lower the threshold when engine operation again stabilizes as may be at the new engine speed.

In one embodiment, the controller is configured to lower the at least one threshold level after the delay period has passed. This allows for a post-effect of accepting a change in operation without unnecessarily generating an alarm.

In one embodiment, two sensors are arranged in each cylinder, one of which is a front sensor and one of which is a rear sensor, and as described above, the controller may determine whether the main bearing or crosshead and / or crankpin bearing are worn. Is configured to determine. To determine if the main bearing is worn or in critical condition, the front sensor of the first cylinder is compared with the rear sensor of the second cylinder. The front sensor of the first cylinder is combined with the rear sensor of the same cylinder to determine if the crosshead and / or crank pin bearings are worn or in critical condition.

Thus there are two sensor readings that can be used for the main bearing and the crosshead and / or crank pin bearings.

In one embodiment, the controller is configured to combine the readings of the two sensors and compare the results of the two sensor readings to the alarm threshold level.

For an embodiment with four cylinders each cylinder is arranged with two sensors (S _F1 ; S _A1 ), (S _F2 ; S _A2 ), (S _F3 ; S _A3 ) and (S _F4 ; S _A4 Provides all eight sensors, denoted by), S _F1 is the front sensor for cylinder 1 and S _A1 is the rear sensor for cylinder 1, where cylinder 1 is the closest to the engine output ( That is, the cylinder 1 is the rearmost cylinder in the example herein), the combined sensor value S _M12 for the main bearing between the cylinder 1 and the cylinder 2 is:

S _M12 = S _F1 + S _A2 ; ego,

The combined sensor value S _CC1 for the crosshead and / or crank pin bearing of the cylinder 1 is:

S _CC1 = S _F1 + S _A1 .

In one embodiment, the sensor values are compensated by subtracting the reference value as before. In one such embodiment, the controller is configured to sum the compensated sensor values and calculate the absolute value of the sum.

For the main bearing between cylinder 1 and cylinder 2 S _M12 is as follows:

S _M12 = S _F1 -S _F1ref + S _A2 -S _A2ref

Since any change in BDC level is doubled before comparison, the sensitivity of the measurement is further improved by comparing the sum of the two sensors, which is advantageous because the difference is very small.

It should be noted that the threshold levels for alarm, prewarning and deceleration are not the same for single sensor values because they are combined sensor values.

In one embodiment, the controller is configured to detect a sudden change in sensor values.

As bearings wear, small changes in BDC levels are expected over time during engine operation. However, such changes occur very slowly and are difficult to distinguish from other changes such as changed engine environment (temperature, thrust, etc.) and the controller is configured to focus on the BDC level instead of the level change.

However, a sharp change in BDC levels can indicate that something is just going wrong. This is the case when some contaminants enter the oil system and the bearings wear more quickly.

Although the change is still within the acceptable limits (below the threshold limit for various alarms), the rate of change can lead to serious damage if not stopped in time, and in some cases an alarm is generated if the change is rapid. It may be too late.

In one embodiment, the controller is configured to detect a sudden change in BDC level by comparing sensor values with previous but recent levels. This allows the controller to determine whether there is a significant change in the last period even if such change is within acceptable limits.

In one embodiment, the controller is configured to determine whether a sudden change is occurring by performing an arithmetic analysis by comparing sensor values with at least one previous period (see below).

One advantage of arithmetic analysis is that the compensation table is finely tuned.

In one embodiment, the controller is configured to determine whether a sudden change is occurring by performing exponential analysis by comparing the sensor values with a floating reference level (see below).

One advantage of exponential analysis is that it does not need to store many values and is therefore faster and resource friendly.

In one embodiment, the controller is configured to detect a sudden change in the BDC level by comparing the sensor values with the average level for the previous short period.

In one embodiment, the period is an interval of 1 to 20 minutes. In one embodiment, the period is an interval of 1 to 10 minutes. In one embodiment, the period is 5 to 10 minutes apart. In one embodiment, the duration is 10 minutes. In one embodiment, the period is 5 minutes.

In one embodiment, the time period being compared precedes the measurement by the second time period. In one embodiment, such second period is between 1 and 20 minutes apart. In one embodiment, the second period is an interval of 1 to 10 minutes. In one embodiment, the period is 5 minutes. In one such embodiment, the controller is configured to compare the current measurement with the average level of the first period, with the first period preceding the current time by the second period. In one example where the first period is 10 minutes and the second period is 5 minutes, the measurement of time T is compared to the mean for T-5 and T-15.

 In order to accommodate false readings and other short variations, in one embodiment, the controller is configured to compare the average of the last reading to the average of the sensor signals of the previous period.

In one embodiment, the set includes the number of last received sensor values, the number being in the range of 5-10. In one embodiment, the set is the last five received sensor values. In one embodiment, the set includes the last ten received sensor values.

In order to accommodate false readings and other short variations, in one embodiment, the controller is configured to compare the average of the last five readings with the average of the previous period.

The controller is configured to determine the rate of change from the difference between the average level of the previous period and the current (average) level.

In one embodiment, the controller is configured to determine whether the difference exceeds a threshold level and if so the controller is configured to send a notification to the worker. In one embodiment, the threshold level is 0.2 mm.

In one embodiment, the controller is configured to determine whether the difference exceeds a threshold level, and if so, the controller is configured to send a notification to the log.

In one embodiment, the controller is configured to determine whether the difference exceeds a threshold level, and if so, the controller is configured to generate an alarm.

In one embodiment, the controller is configured to determine whether the difference exceeds a threshold level, and if so, the controller is configured to request deceleration.

Thus, in such a situation, by early indicia, it may be possible to provide which can prevent a potentially serious engine failure.

Rapid change detection through exponential analysis

In one embodiment, the controller is configured to perform exponential analysis of sensor values and determine whether an alarm should be generated.

In one embodiment, the controller is configured to determine the current level by determining a reference level and calculating an exponential average.

In one embodiment, the controller is configured to update the reference level S _reflevel by updating the old reference to the compensation value S _comp using a low pass filter with an update factor. .

In one embodiment, this is expressed as follows.

S _refleverlnew = S _reflevelold * (1-x) + S _comp * x

Where x is the update factor.

The reference level is an indication of the current normal level and should therefore work relatively slowly. Therefore, the update factor should be chosen small. In one embodiment, the update factor x is chosen to be 0.0001.

In one embodiment, the controller updates the current state level S _pres by updating the old reference state to the compensation value S _comp using a low pass filter with an update factor. It is configured to.

In one embodiment, this is expressed as follows.

S _presnew = S _presold * (1-y) + S _comp * y

Where y is the update factor.

The current state level is an indication of the current state of the BDC level and should therefore react relatively quickly to respond to rapid changes. Therefore, the update factor should be chosen to be large. In one embodiment, the update factor y is chosen to be 0.2.

In one embodiment, the controller is configured to calculate a S _refvalue . In one embodiment, the reference value is the difference between the reference level and the current state:

S _refvalue = S _pres -S _reflevel

In one embodiment, the controller is configured to analyze the reference value to determine whether an alarm should be generated.

9 illustrates a method for detecting abrupt changes in the BDC level of a bearing using an exponential algorithm in accordance with embodiments herein.

In steps 910 and 920 a signal indicative of the BDC level is received and compensated according to the engine operating condition compensation table.

In step 930, calculations for the reference level, current state, and reference value as described above are performed.

In one embodiment, the controller is configured to analyze the reference value of a single sensor to determine if a sudden change is occurring. If the reference value exceeds the threshold, it is determined that a sudden change occurs. In FIG. 9 such calculations are performed at step 960.

Determining wear from only one sensor reading enables uneven wear detection (in the axial direction) of the bearing.

In one embodiment, the threshold level for only one sensor is 120.

In one embodiment, the threshold level for only one sensor exceeds 120.

In one embodiment, the threshold level for only one sensor exceeds 110.

In one embodiment, the controller is configured to analyze the sum SUM of the reference values of the sensors of a single cylinder to determine that a sudden change is taking place. If the sum exceeds the threshold, it is judged that a sudden change occurs. Sudden changes can occur in the cylinder's crosshead bearings or crank pins. Such calculations are performed at (alternative) step 940 of FIG. 9, and a determination as to whether the limit of the alarm is exceeded is performed at step 960.

Determining wear from the readings of the two sensors allows for rapid detection of the bearing since such readings simultaneously increase and thus the sum of readings doubles quickly. In one embodiment, the threshold level for the sum (SUM) is greater than the threshold level for a single sensor to accept that the sum is greater than two individual sensor readings.

In one embodiment, the threshold level for the sensors in the cylinder is 170.

In one embodiment, the threshold level for the sensors in the cylinder exceeds 170.

In one embodiment, the threshold level for the sensors in the cylinder is greater than 160.

In one embodiment, the controller is configured to analyze the sum of the reference values of the sensors from one cylinder with a reference value of one sensor of a neighboring cylinder to determine that a sudden change is occurring. If the sum exceeds the threshold, it is judged that a sudden change is occurring. A sudden change can be in the main bearing between the two cylinders. Such calculations are performed in (alternative) step 950 of FIG. 9, and a determination as to whether the limit of the alarm is exceeded is performed in step 960.

Determining wear from the readings of two sensors of two different cylinders makes it possible to detect wear of the main bearing much faster since the two readings appear to grow faster than with the sensors in the set of cylinders. In one embodiment, the threshold level for neighboring cylinders is greater than the threshold level for the collection of cylinders so as to accept an increasing sum more than in the collection of cylinders.

In one embodiment, the threshold level of the sensors in neighboring cylinders is 220.

In one embodiment, the threshold level of the sensors in neighboring cylinders exceeds 220.

In one embodiment, the threshold level of the sensors in neighboring cylinders exceeds 210.

It should be noted that all these steps 940 and 950 need not be performed.

In one embodiment, the controller is configured to generate an alarm request (not shown) if it is determined that a sudden change (step 965) has occurred.

In one embodiment, the controller is configured to generate a deceleration request (step 970) if it is determined that a sudden change (step 965) has occurred. Since the changes are rapid, it is important that the measurements be made quickly to prevent damage from occurring and that the deceleration provides the fastest healing for rapid changes.

In one embodiment, the controller is configured (step 980) so that information about sudden changes is stored in a logfile.

It allows the controller to react quickly to sudden changes without having to store multiple values for each sensor and also to prevent further wear or damage to the bearings.

A dynamic alarm limit or threshold level may be used when monitoring abrupt changes to handle variations in BDC levels due to engine speed changes.

In one embodiment, the dynamic alarm limit or threshold level is calculated based on a change in engine speed RPM (Revolution Per Minute) and the dynamic threshold level increases as the engine speed increases.

In one embodiment, the controller is configured to receive an input indicating the new speed or the current speed, indicated by RPM _N.

The controller is configured to update the reference speed based on the new speed. In one embodiment, the controller is configured to update the reference speed via an exponential moving average as follows:

RPM _refnew = RPM _refold * (1-z) + RPM _N * z

The controller is also configured to calculate the change in RPM, expressed in ΔRPM, by calculating the absolute value of the difference between the current speed (RPM _N ) and the reference speed:

ΔRPM = │RPM _N -RPM _ref │

In one embodiment, ΔRPM is set to be 3 for all values greater than three. This ensures that the alarm limit is increased without getting too high.

Depending on which sensor combination (single sensor, or the same cylinder or neighboring cylinder) should be monitored, the basic threshold level or basic alarm limit indicated by alarm _basic is set to be one of the thresholds listed above.

In one embodiment, the controller is further configured to calculate the first candidate dynamic threshold level (denoted by alarm 1) based on the amplification constant denoted by k as follows:

alarm 1 = alarm _basic (1 + ΔRPM * k)

In one embodiment, the controller is set to use the first candidate threshold level as the dynamic threshold level.

 In one embodiment, the controller has a number of engine speed readings received at the last time the threshold level was increased, denoted by H, an amplification constant denoted by k, and a delay constant denoted by β, as follows. Is further configured to calculate a dynamic threshold level of the second candidate based on the.

alarm 2 = alarm _basic (1 + ΔRPM * k * Exp (-H / β))

In one embodiment, the controller is set to use the threshold level of the second candidate as the dynamic threshold level.

As the alarm level increases, the amplification constant increases. Examples of amplification constants are 0.1, 0.15, 0.2, 0.25 and 0.3. In one embodiment, the amplification constant is in the range of 0.05 to 0.4.

Examples of delay constants are 190, 200, and 210. In one embodiment, the delay constant is in the range of 150 to 200.

In one embodiment, the controller is configured to determine the highest threshold level of candidate threshold levels and use it as the dynamic threshold level:

Dynamic threshold level = max (alarm 1, alarm 2)

The controller can thus be adapted to variations and still detect rapid changes in bearing wear.

It should be noted that the exponential analysis of the abrupt changes described above is appropriate for four-stroke engines. In one embodiment, the engine is a two-stroke engine. In one embodiment, the engine is a four stroke engine.

To handle all variable factors in the monitoring of the engine, the monitor device is initially calibrated during the learning phase.

A look-up table of engine speed compensation should be obtained during the "learning process" performed by the controller.

In one embodiment, the learning phase has a duration of 500 hours.

In one embodiment, the controller is configured to set a speed compensation table for each sensor 170.

In the case of a wear monitoring system installed in a newly built engine, it is important that the system can protect the bearings from the earliest possible time when performing running tests at the factory or commissioning at sea. Thus, a rough calibration curve will be established as soon as an average value of 10 minutes is achieved from one fixed engine speed. This calibration curve is readjusted so that three fixed engine speeds are used during the learning process.

5 shows an overall flow chart for providing a schematic calibration. The controller has a curve of BDC level versus engine speed and is configured to make a rough estimate of engine speed compensation by calculating an approximation of the table values.

This rough estimate allows some control during the learning phase.

In one embodiment, the controller receives 510 values for each sensor at one given engine speed (or rpm). The values are averaged (520), and a preliminary curve is created from the estimated change in engine size over the speed range and the averaged engine speed-BDC-level coordinates or control point (530). In one embodiment, the expected change is precomputed and stored in a table such as Table 1.

Expected change by engine type Engine type (bore, cm)  mm change (20-110% rpm)  80 to 98  -0.35  60 to 70  -0.25  Up to 50  -0.15

6 is a preliminary curve or curve of a rough estimate of curve 600, which has a control point 610 for the average BDC level of a particular engine speed.

Curve 600 is a rough estimate and the controller is configured to use it as a reference only during the rough calibration curve.

In one embodiment, a second speed is selected and the controller receives 540 a value for each sensor at the second engine speed. The values are averaged 550 and the curve is updated 560 to process the second averaged engine speed-BDC-level coordinate or control point.

In one embodiment, the controller is configured to repeat steps 540-560 for the third speed. Such is indicated by the dashed line in FIG. 5.

In step 570 the controller completes the rough correction curve 700 by interpolating between the control points 710, 720, 730 and extrapolating to cover the entire range of engine speed.

In one embodiment, the engine speed range is 0-120%. In one embodiment, the engine speed range is 20 to 110%.

7 shows an exemplary curve of a schematic correction 700 with three control points 710, 720, 730 of average BDC level for three engine speeds.

In one embodiment, the engines are run for 10 minutes each at each speed. It should be noted that other driving times may also be used.

In one embodiment, the controller is configured to select three speeds according to Table 2.

Speed and corresponding speed interval  Speed number  speed  One 20 to 50% of standard speed  2 50 to 80% of standard speed  3 80-100% of standard speed

In one embodiment, the controller is configured to space the selected three speeds at intervals of at least 20% of the standard speed to ensure that the control points are properly spaced in the curve 700.

In one embodiment, the controller is configured to use a rough calibration curve 700 during the remainder of the learning phase to allow some threshold of wear during the learning phase.

In one embodiment, the controller is further configured to receive sensor values and update the table of BDC-level vs. engine speeds during free operation of the engine at various speeds.

8 shows a method of an embodiment of the present application for completing an engine speed-BDC table.

In one embodiment, the steps of FIG. 8 are performed in parallel for all sensors.

In a first step 810, the value or signal (S _N) is received by the controller. The controller then determines whether the compensation is valid for the current speed.

Since a predetermined number of samples has been received for one engine speed, the controller calculates a reference value for that engine speed and generates a first reasonable compensation value by averaging the received samples for that sensor at that speed. And the engine speed compensation table is updated.

In one embodiment, the controller is configured to receive and sample 1000 samples for each engine speed.

If the compensation is determined to be reasonable, the controller is configured to calculate the compensation value by subtracting the reference value from the received signal (step 820):

S _comp = S _N -S _ref

If it is determined that the compensation is not valid, the controller is configured to calculate the compensation value by subtracting the reference value from the received signal (step 825);

S _comp = S _N -S _{ref, rough}

In one embodiment, the controller is further configured to apply a filter to reduce noise in the received signal.

In one embodiment, the controller is configured to then calculate a sensor deviation d (S _sensor ):

d (S _sensor ) = S _sensor -mean of other sensors

In one embodiment, the controller is further configured to calculate the cylinder deviation d (cylinder):

d (cylinder) = (S _{cylinder , fore} + S _{cylinder , aft} ) / 2-average of other sensors

In step 840 of Figure 8 both deviations are calculated.

In one embodiment, the controller is configured to determine whether the alarm threshold for the sensor value has been exceeded (850) and if so activate (860).

In one embodiment, the controller is configured to determine whether the alarm threshold for cylinder deviation has been exceeded (850) and if so activate (860).

In one embodiment, the controller is configured to determine whether the alarm threshold for sensor deviation has been exceeded (850) and if so activate (860).

Three determinations related to the alarm threshold in FIG. 8 are performed at step 850.

In one embodiment, the alarm threshold for sensor values during the learning phase is +/− 0.8 mm.

In one embodiment, the alarm threshold for sensor deviation during the learning phase is +/− 0.5 mm.

In one embodiment, the alarm threshold for cylinder deviation during the learning phase is +/− 0.4 mm.

If the controller determines that the alarm is active, the controller is further configured to store the event in a log file (870).

In one embodiment, the controller is configured to determine if the deceleration limit for the sensor deviation has been exceeded (880) and if so activate the request of the deceleration process (890).

In one embodiment, the deceleration threshold for the sensor value during the learning phase is +/- 0.9 mm. In one embodiment, the deceleration threshold for sensor deviations during the learning phase is +/- 0.7 mm.

In one embodiment, the controller is configured to return to step 810 for receiving a new signal value.

In one embodiment, the controller is configured to perform steps 810-840 for each rotation.

In one embodiment, the controller is configured to perform steps 850 through 890 for each rotation.

In one embodiment, the controller is configured to perform steps 850-890 at intervals. In one embodiment, the spacing is in the range of 1 to 50 revolutions. In one embodiment, the spacing is in the range of 10 to 30 revolutions. In one embodiment, the interval is 30 turns. This is indicated by the dashed line in FIG. 8.

To ensure that the full engine range is included in the learning phase, the controller is configured to receive samples for different engine speeds over the range of available engine speeds.

In one embodiment, the controller is configured to receive samples for 100 engine speeds.

In one embodiment, the controller is configured to receive samples from each sensor for each engine speed, ie receive samples for each possible revolution per minute within engine range.

In one embodiment, the controller is configured to determine a reference point for each speed point that was not valid during the learning phase. In one embodiment, the controller is configured to determine the reference value by interpolation from the reference values of adjacent speed points. In one embodiment, the controller is configured to determine the reference value by extrapolation from the reference values of the reference points of the rough estimate.

In one embodiment, the controller is configured to recalculate the average of signal values for each sensor at 50 time intervals at each speed point. This allows the system to adapt and respond to changes in engine structure.

In one embodiment, the controller determines whether the reference value for any engine speed has been changed by a value greater than the update threshold when compared to a valid compensation value first obtained, and if so activates an alarm informing it. It is composed. In one embodiment, the update threshold is 0.2 mm.

The learning phase is divided into three stages to ensure reliable monitoring of the wear of the bearings during the broad learning phase. The first stage produces a very rough preliminary estimate, which is used as a reference for the second stage in which a complete rough estimate is completed. A rough completion estimate is then used throughout the rest of the learning phase (step 3).

This ensures that the wear of the bearings is monitored even during engine start. This makes it possible to detect an increase in wear due to, for example, incorrect installation and irregularities, which protects the bearing even during engine downtime.

Simple correction cannot take into account problems during startup and therefore the learning phase disclosed herein is very advantageous.

During the life of the engine, the engine will undergo a series of maintenance actions and overhauls. For example, the bracket supporting the sensor (s) should be removed due to overhaul of the main bearings. When reinstalling the bracket, it should be expected that the sensor (s) will be positioned differently. It may also be necessary to replace the sensor after it has been damaged or has failed. The sensor may also need to be readjusted if the bracket holding the sensor is slightly bent.

This will require recalibration of the speed compensation table or the speed compensation curve for one or several of the sensors.

The adjustment is made by adjusting the offset of the individual sensor.

In one embodiment, the controller is configured to adjust the signals from the sensor by compensating the signal value according to an existing speed compensation lookup table or speed compensation curve. The difference between the measured BDC level and the reference value during normal operation is zero (at least on average). Thus the compensated value will reflect the offset to the sensor since the absolute value of the compensated value will now be greater (at least on average) than zero.

In one embodiment, the controller is configured to calculate an average of the offsets over a period of time. In one embodiment, the period is 50 hours.

In one embodiment, the controller is configured to offset reference values for the affected sensor according to the calculated average offset.

However, since there is a time lapse between the failure of the sensor and the replacement of the sensor and the time lapse is relatively long in some circumstances, there is a risk that the wear of the bearing will not be detected during such time lapse.

To accommodate any wear of the bearing, the controller is configured to perform reconditioning based on a combination of signals from the average and neighbor sensors taken over a period of time before and after replacement. In one embodiment, the period is 500 hours.

10 is a schematic diagram of a speed compensation curve for two sensors, wherein

a ₁ t ₁ + b ₁ is the curve for the first sensor for 500 hours before sensor failure;

a ₂ t ₂ + b ₂ is the curve for the first sensor for 500 hours after sensor replacement;

a ₃ t ₃ + b ₃ is the curve for the neighbor sensor during the time the first sensor failed.

In this formula, 'a' represents slope, 't' is time, and 'b' is a constant representing the starting point of the curve for t = 0.

In one embodiment, the controller is configured to generate these three lines by performing three different root mean square lines that best fit based on the average of the compensated and filtered sensor values over six hours. It is composed.

In one embodiment, the controller is configured to use speed compensation for neighboring sensors during readjustment of the sensors.

After the period for reconditioning the sensor has elapsed, the offset O for the replaced sensor can be calculated.

In one embodiment, the controller is configured to calculate the offset for the replaced sensor, in one embodiment, it is as follows:

O = O ₁ + a ₃ t _b + Ta ₂

Where O ₁ is the offset during which the sensor failed;

t _b is the time the sensor failed;

T is a period (in one embodiment, T = 500).

In one embodiment, the controller is configured to exclude the replaced sensor when calculating sensor deviation and / or cylinder deviation for other sensors during the period after replacement of the sensor or period reconditioning for the sensor.

In one embodiment, the controller is configured not to calculate sensor deviation and / or cylinder deviation for the replaced sensor after the period readjustment for the sensor.

In one embodiment, the controller is configured to suppress generating a deceleration request or activating an alarm for sensor values resulting from the replaced sensor during the reconditioning period.

This enables a learning phase only for the affected or replaced sensor and does not require a complete restart of the learning phase for all sensors. This allows for safer monitoring during the re-adjustment phase than a total rerun of the learning phase for all sensors that would have been equipped.

In bearing wear monitoring systems, data storage serves two purposes. The primary purpose is to be able to retrieve the data if any bearing damage has occurred. In one embodiment, it is implemented as a "black box" function.

The second object relates to the inspection of bearings. Traditionally, bearings are opened for routine inspection on a time-based schedule. For example, all bearings must be opened at four or five year intervals. In order to avoid unnecessary opening of the bearings, it is desired to switch from time-based inspection to state-based inspection. For this purpose, the stored data can be used to generate trend curves that indicate whether any wear occurred during the inspection period. Such curves can be presented to a class surveyor.

In one embodiment, the controller is configured to facilitate storage of filtered values having a time stamp available from the last 24 hours for each sensor. In one embodiment, such filtered values are stored for short term storage. In one embodiment, a data set is needed every 30 revolutions of the engine. In case the alarm limit is exceeded, the controller is configured to store a copy of the short term storage separately as a "frozen copy". In one embodiment, the controller is configured to include data for five minutes after the alarm time in copy.

In one embodiment, the controller is configured to facilitate storage of maximum, minimum and average filtering values for each sensor. In one embodiment, such maximum, minimum and average values are stored for long-term storage. In one embodiment, the maximum, minimum and average filtering values are stored for uptimes every six hours. In one embodiment, the maximum, minimum and average filtering values are stored with a time stamp.

In one embodiment, an event log is also stored. In one embodiment, the event log includes the following information:

Any alarms, slowdowns or emitted advance warnings or changes during the learning process;

Offset adjustment and / or possible replacement of any sensors;

Change in sensor reference from coarse correction to fine correction;

Random reset of the reference level to advance warning.

In one embodiment, all information is time stamped and all storage and event logs are kept in nonvolatile memory.

In one embodiment, the device is configured to download stored data and events to an external device such as a PC. Such data may be for presentation to the Surveyor of the Society.

In one embodiment, the data includes the following.

Engine Information Part. This includes information on ships and engines. In one embodiment, the information is as follows.

Name of ship = XXXXXXX

IMO Number = XXXXXXX

Tier Registration Number = XXXXXXX

Component = XXXXXXX

Engine licenser = XXXXXXX

Engine maker = XXXXXXX

Engine type = XXXXXXX

Engine serial no. = XXXXXXX

CM system type = bearing wear monitoring system

CM System Maker = XXXXXXX

CM system hardware = XXXXXXX

CM system software = XXXXXXX

Trend data period from = YYYY-MM-DD

Trend data period until = YYYY-MM-DD

Engine operating time from = 99999

Engine runtime up to = 99999

The log portion of all changes in system state and sensor state following an event load. The format is [DATE] [TIME] [EVENT].

Trent part of the filtered value. Derived from "Long term storage". The following data is presented for each sensor every six hours of engine run time: time stamp, engine run time, and average filtering value of six hours. The format is, in one embodiment, [DATE AND TIME: YYYY-MM-DD hh: mm: ss]; [ENGINE OPERATING HOURS: h]; [DISTANCE: mm].

Status part. The purpose of this pile is to provide a quick overview of each cylinder indicating whether the opening of the bearing associated with the cylinder for inspection is justified due to detected wear or other circumstances. Such an environment may be the detection of a loss of baseline or wear exceeding a "significance limit" during sensor exchange. In one embodiment, the state appears as four levels of presentation. The four levels are as follows:

Normal "N" indicating no wear was detected above the pre-warning limit;

Prewarning "W" indicating that wear above the prewarning limit has been detected;

Alarm "A" indicating that an alarm was generated from sensors connected to the cylinder, and

Unknown "U" indicating that the sensor of the cylinder has lost its reference or the sensor's reference curve has been modified due to wear detected by the "neighbor" of the sensor during exchange. If the damaged sensor remains unchanged, the same indication is given.

In one embodiment, the apparatus is configured to provide long term storage, short term storage and complete data of reference curves for each sensor.

Various aspects of the above may be used alone or in various combinations. The teachings of the present application may be implemented by a combination of hardware and software, but may also be implemented in hardware or software. The teachings of the present application may be embodied as computer readable code on a computer readable medium.

What is taught in this application has several advantages. Different embodiments or implementations can yield one or more of the following advantages. It should be noted that it is not an exclusive enumeration and that there may be other advantages not described here. For example, one advantage of the teachings of the present application is that the device according to the present application provides reliable monitoring that accepts several (external) factors.

Another exemplary advantage of the teachings of the present application is that the monitoring of wear accommodates deformations caused by thrust.

Another exemplary advantage of the teachings of the present application is that monitoring of bearing wear is reliable even in the correction phase.

Another exemplary advantage of the teachings of the present application is that replacement of the sensor can be made and readjusted in a more reliable manner.

Although attention has been paid to features of the invention believed to be of particular importance in the foregoing specification, the Applicant, whether or not specifically emphasized, does not apply to any patentable feature or combination of features described above and / or shown in the drawings. Claim protection.

Terms such as "comprising" described in the claims do not exclude other elements or steps. The indefinite article described in the claims does not exclude a plurality. The unit or other means may perform the function of several units or means described in the claims.

Claims (15)

A device for monitoring the wear of crosshead bearings, crankpin bearings and main bearings in large two-stroke diesel engines.
The apparatus comprises at least two sensors, the sensors arranged and configured to measure a bottom dead center level in a given cylinder relative to a fixed point of the engine, the apparatus further comprising a controller,
The controller is:
Receive a signal from each sensor;
Compensating each signal according to the engine operating condition;
Determine whether the threshold has been exceeded, and if so generate an indication of the exceeded threshold,
The controller,
Generate an engine operating condition compensation table during operation of the engine in learning phase by sampling the number of first sensor values against the number of second engine operating condition points during operation of the engine,
Crosshead bearing, crankpin bearing, and in a large two-stroke diesel engine, further configured to set a reference value by averaging the received sample values for a speed point when the number of first samples has been received for engine operating conditions. Device for monitoring the wear of the main bearings. The method of claim 1,
The controller is:
Receive a signal value from at least one sensor over a period of time for a first engine operating condition;
Average signal values to produce a first reference value;
To set a rough calibration estimate of engine operating condition compensation by extrapolating other engine operating conditions based on a first reference value for the engine operating condition using a predetermined estimate change factor. Composed,
And the controller is configured to compensate for further received signals in accordance with a rough correction estimate during the learning phase. The apparatus of claim 1, wherein the wear of the crosshead bearing, crankpin bearing and main bearing in a large two-stroke diesel engine. The method of claim 2,
The controller,
Receive a signal value from at least one sensor over a period of time for one second engine operating condition;
Average the signal values to produce a second reference value;
Interpolating between a first reference value and a second reference value for velocities that are between the first speed and the second speed; Further configured to update the coarse correction estimate by extrapolating engine operating conditions that lie outside the first and second engine operating conditions based on first and second reference values using a predetermined estimate change factor,
And the controller is configured to further compensate the received signal values in accordance with the coarse correction estimate during the learning phase. 2. The apparatus of claim 1, wherein the wear of the crosshead bearing, the crankpin bearing and the main bearing in a large two-stroke diesel engine. The method of claim 1,
Wherein the operating condition is engine speed and the engine operating condition point is a speed point. The apparatus for monitoring wear of crosshead bearings, crankpin bearings and main bearings in a large two-stroke diesel engine. The method of claim 1,
And said operating condition is a propeller pitch level. A device for monitoring wear of crosshead bearings, crankpin bearings and main bearings in large two-stroke diesel engines. The method of claim 1,
Wherein said operating condition is a load, the apparatus for monitoring wear of crosshead bearings, crankpin bearings and main bearings in large two-stroke diesel engines. The method of claim 4, wherein
The controller is configured to receive signals for three engine speeds, wherein the three engine speeds are:
A first engine speed taken from the 20-50% range of standard engine speed;
A second engine speed taken from the 50-80% range of standard engine speed; And,
Apparatus for monitoring wear of crosshead bearings, crankpin bearings and main bearings in large two-stroke diesel engines, the third engine speed being taken from a range of 80 to 100% of standard engine speed. The method of claim 3, wherein
Wherein the controller is further configured to update the coarse correction estimate with an engine operating condition compensation table during the learning phase. 4. The apparatus of claim 1, wherein the wear of the crosshead bearing, the crankpin bearing and the main bearing in a large two-stroke diesel engine. The method of claim 2,
The controller is further configured to update the engine operating condition compensation table with new reference values by resetting the reference value for each engine operating condition point at intervals of time, crosshead bearing, crankpin in a large two-stroke diesel engine. Device for monitoring the wear of bearings and main bearings. The method of claim 9,
The controller is further configured to determine whether the reference value for the engine operating condition point has been changed by a factor in comparison with the obtained first reference value and, if so, further activate the alarm to cross in a large two-stroke diesel engine. Device for monitoring wear of head bearings, crankpin bearings and main bearings. The method of claim 8,
The controller is further configured to update the engine operating condition compensation table after the learning phase by interpolating and extrapolating between the values of the engine operating condition compensation table and the rough calibration estimate. Device for monitoring the wear of crosshead bearings, crankpin bearings and main bearings in the engine. The method according to any one of claims 1 to 11,
The apparatus includes two or more sensors, and the controller is configured to determine a sensor deviation for each sensor based on received sensor values to determine a deviation of each sensor from an average of other sensors. , For monitoring the wear of crosshead bearings, crankpin bearings and main bearings in large two-stroke diesel engines. The method according to any one of claims 1 to 12,
Wherein the engine is a large two-stroke marine diesel engine, the apparatus for monitoring wear of crosshead bearings, crankpin bearings and main bearings in a large two-stroke diesel engine. A marine vessel comprising the engine according to any one of claims 1 to 13. A method of executing a device having a controller configured to perform a command stored on a physical medium, the method comprising:
The practice is to monitor the wear of the crosshead bearings, crankpin bearings and main bearings of large two-stroke diesel engines,
The apparatus comprises at least two sensors, the sensors arranged and configured to measure the bottom dead center level in a given cylinder relative to a fixed point of the engine,
The execution method is
Receiving a signal from each sensor;
Compensating each signal according to the engine operating condition;
Determining whether the threshold has been exceeded, and if so generating an indication of the exceeded threshold,
The execution method is
Generating an engine operating condition compensation table during operation of the engine in learning phase by sampling the number of first sensor values against the number of second engine operating condition points during operation of the engine;
And setting a reference value by averaging the sample values received for the engine operating condition point when the number of first samples has been received for the engine operating condition point. Method of execution of the device having a.

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