CH702986B1 - Improved monitoring the wear of bearings in a two-stroke large Diesel engine. - Google Patents

Abstract

The invention relates to a device and a method for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a two-stroke large diesel engine. The apparatus includes at least two sensors arranged and configured to measure a level of bottom dead center for the crosshead or a sliding block in a particular cylinder with respect to a fixed point of the engine. In a learning phase, a table is generated with reference values for compensation of engine operating conditions. Normal operation includes the steps of: receiving a signal from each sensor; Compensating each signal (420) with a reference value in response to the current engine operating condition; Determining if a threshold has been exceeded (450) and, if so, outputting an exceeded threshold indication.

Description

area

The present invention relates to an apparatus and a method for measuring and monitoring the wear of bearings in a two-stroke large diesel engine.

background

The main bearings, the crank pin bearings and the crosshead bearings of two-stroke large diesel engines have a lower and an upper bearing shell, which define a bearing surface for supporting a corresponding journal. The bearing shells have a steel support shell with a bearing metal layer thereon. The bearing metal is normally a tin-aluminum alloy or a white metal alloy in a layer about 1.5 to 2 mm thick.

Despite great caution in the production of these engines and the operation, there is a small failure rate. Since most two-stroke large diesel engines are seagoing, a motor failure due to a faulty bearing is highly undesirable.

In addition, the cost of a bearing overhaul can be increased if, for example, a regrinding of the crankshaft is required, which can lead to a significant downtime for the engine.

[0005] In order to prevent this from happening, the classification societies require that, depending on the classification society, inspections be carried out every four or five years during which the bearings are dismantled and tested.

These tests are quite complex and require the dismantling of the bearings and then the re-assembly of the bearings. This process involves a significant risk of installation error, i. an error introduced during the overhaul.

In order to reduce the need for tests, the prior art proposed to monitor the wear of a bearing by measuring its distance.

US patent application US2007 / 0 017 280 discloses measuring the position of a sliding jaw of a crosshead by using two sensors for each cylinder. This allows the detection of wear on the main bearings, the crankpin bearings and crosshead bearings as well as determining whether the wear on the main bearings or on the crankpin bearings and the crosshead bearings is. These measurements are used to determine whether the wear is about to result in a failure or not and to issue a warning when a failure is imminent.

As already mentioned, the consequences of a failure can be bad, so that an effective and accurate way of detecting the wear of a bearing is of great use.

Summary

Against this background, it would be advantageous to provide an apparatus and method that improve the effectiveness and accuracy of the prior art systems by providing a method and apparatus that can be used to calibrate and / or interpret the sensor readings better way are designed.

The main objective of monitoring the wear of bearings is to detect a bearing failure before it develops so much that heat causes damage to parts other than the bearing sliding surface. Parts that could be affected are the crosshead, crankpin, main journal, or bearing housing due to deformation. Such damage is generally the result when the bearing sliding surface is worn through and contact is made between the shaft and the steel support shell of the bearing shell.

It should be noted that, although the following description places emphasis on compensating for engine speed, the teachings herein also apply to compensating for a propeller pitch level and a load. These are examples of engine operating conditions that affect bottom dead center (BDC) for a moving part, such as a crosshead or sliding jaw, for example, in an engine.

The invention is characterized by the features of the independent claims 1 and 15. Advantageous embodiments of the invention are specified in the dependent claims 2 to 12. Advantageous uses of the invention with reference to claims 1-12 defined in claims 13 and 14. Important aspects of the invention will be explained in more detail below.

The disclosed embodiments provide an apparatus for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a two-stroke large diesel engine, the device comprising at least two sensors, the sensors being arranged and configured to have a bottom dead center for the crosshead and a sliding block of a particular cylinder with respect to a fixed point of the motor, the device further comprising a controller configured to: receive a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining a deviation to account for factors affecting the sensor signal; Determining if a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold.

In one embodiment, the engine operating condition is an 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 a deviation of a sensor signal, the controller is able to account for external influences that affect more than one sensor and that would otherwise be interpreted as a change in BDC level.

The aspects of the disclosed embodiments further relate to providing a method of implementation in a device having a controller adapted to execute instructions stored on a physical medium, the method of monitoring wear of a crosshead bearing, a Crankpin bearing and a main bearing in a two-stroke large diesel engine, and the device comprises at least two sensors, wherein the sensors are arranged and configured to a bottom dead center for the crosshead or a sliding block in a particular cylinder with respect to a fixed point of Motor, the method comprising: receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining a deviation to account for factors affecting the sensor signal; Determining if a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold.

The aspects of the disclosed embodiments further relate to providing a device for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a two-stroke large diesel engine, the device comprising at least two sensors, the sensors being arranged and configured such that they measure a bottom dead center for the crosshead or a sliding block in a particular cylinder with respect to a fixed point of the motor, the device further comprising a controller configured to: receive a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold, and wherein the controller is further configured to dynamically alter the threshold according to a current operation of the engine.

The aspects of the disclosed embodiments further relate to providing a method of implementation in a device having a controller adapted to execute instructions stored on a physical medium, the method of monitoring wear of a crosshead bearing, a Crankpin bearing and a main bearing in a two-stroke large diesel engine, and the device comprises at least two sensors, wherein the sensors are arranged and configured so that they have a bottom dead center (BDC) for the crosshead or a sliding block of a particular cylinder with respect to a fixed Point of the engine, the method comprising: receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold, and wherein the method further comprises dynamically changing the threshold according to a current operation of the engine.

The aspects of the disclosed embodiments further relate to providing a device for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a two-stroke large diesel engine, the device comprising at least two sensors, wherein the sensors are arranged and configured such that they measure a bottom dead center for the crosshead or a slide shoe in a particular cylinder with respect to a fixed point of the engine, and wherein the at least two sensors are arranged so that there are two sensors in each cylinder, a front and a rear sensor, the apparatus further comprising a controller configured to: receive a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold, and wherein the controller is further configured to: determine by linking the signal of the front sensor of a first cylinder to the signal of the rear sensor of one second cylinder that a bearing is worn, and / or determining by associating the signal of the front sensor of a first cylinder with the signal of the rear sensor of the same cylinder that a bearing is worn, and linking at least two such linked sensor signals and comparing the result this link to the threshold.

The aspects of the disclosed embodiments further relate to providing a method of implementation in a device having a controller adapted to execute instructions stored on a physical medium, the method of monitoring wear of a crosshead bearing, a Crankpin bearing and a main bearing in a two-stroke large diesel engine, wherein the device comprises at least two sensors, wherein the sensors are arranged and configured to a bottom dead center for the crosshead or a sliding block in a particular cylinder with respect to a fixed point of Motor, the method comprising: receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold, and wherein the method further comprises determining by associating the signal of the front sensor of a first cylinder with the signal of the rear sensor of a second cylinder in that a bearing is worn or in a critical condition, and / or determining by linking the signal of the forward signal of a first cylinder to the signal of the rear sensor of the same cylinder that a bearing is worn or in a critical condition, and linking the two Sensor signals and comparing the result of the two sensor signals with the threshold.

The aspects of the disclosed embodiments also relate to providing a device for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a two-stroke large diesel engine, the device comprising at least two sensors, wherein the sensors are arranged and configured such that they measure a bottom dead center for the crosshead or a sliding block in a particular cylinder with respect to a fixed point of the motor, the device further comprising a controller configured to: receive a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold, and wherein the controller is further configured to: detect a rapid change in the BDC level by comparing the received sensor signals with a mean level of Signal values for a previous period of time.

The aspects of the disclosed embodiments further relate to providing a device for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in an engine, the device comprising at least two sensors, wherein the sensors are arranged and configured to provide one measuring dead center for the crosshead or a sliding jaw in a particular cylinder with respect to a fixed point of the engine, the apparatus further comprising a controller configured to: receive a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold, and wherein the controller is further configured to: detect a rapid change of a bottom dead center level by updating a reference level for a sensor; Updating a current level for a sensor and determining a reference value and determining whether the reference value exceeds a threshold level of rapid change.

The aspects of the disclosed embodiments also relate to providing a method for monitoring wear of a crosshead bearing, a crankpin bearing, and a main bearing in an engine, the device comprising at least two sensors, the sensors being arranged and configured to provide one measuring dead center for the crosshead or a sliding jaw in a particular cylinder with respect to a fixed point of the engine, the apparatus further comprising a controller configured to: receive a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold, and wherein the controller is further configured to: detect a rapid change of a bottom dead center level by updating a reference level for a sensor; Updating a current level for a sensor and determining a reference value and determining whether the reference value exceeds a threshold level of rapid change.

The aspects of the disclosed embodiments further relate to providing a method of implementation in a device having a controller adapted to execute instructions stored on a physical medium, the method of monitoring wear of a crosshead bearing, a Crankpin bearing and a main bearing in a two-stroke large diesel engine, wherein the device comprises at least two sensors, wherein the sensors are arranged and configured to have a bottom dead center for the crosshead or a sliding block of a particular cylinder with respect to a fixed point of the motor measure, the method comprising: receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold, and wherein the method further comprises: detecting a rapid change in a BDC level by comparing the measured sensor values to a mean level for a previous one period of time.

The aspects of the disclosed embodiments further relate to providing a device for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a two-stroke large diesel engine, the device comprising at least two sensors, the sensors being arranged and configured such that they measure a bottom dead center for the crosshead or a sliding block in a particular cylinder with respect to a fixed point of the motor, the device further comprising a controller configured to: receive a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an exceeded threshold indication, and wherein the controller is further configured to: generate a table for compensating engine speed during operation of the engine during a learning phase by sampling one first number of sensor values with respect to a second number of speed points during operation of the engine, and determining, when the first number of samples for a speed point has been received, determining a reference value by averaging the received samples for that speed point.

The aspects of the disclosed embodiments further relate to providing a method of implementation in a device having a controller adapted to execute instructions stored on a physical medium, the method of monitoring wear of a crosshead bearing, a Crankpin bearing and a main bearing in a two-stroke large diesel engine, wherein the device comprises at least two sensors, wherein the sensors are arranged and configured to a bottom dead center for the crosshead or a sliding block in a particular cylinder with respect to a fixed point of Motor, the method comprising: receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining whether a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold, and wherein the method further comprises: generating a table for compensating engine operating conditions during operation of the engine during a learning phase by sampling a first number of sensor values relating to a second number of speed points during operation of the engine and determining, when the first number of samples for a speed point have been received, determining a reference value by averaging the received samples for that speed point.

The aspects of the disclosed embodiments further relate to providing a device for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a two-stroke large diesel engine, the device comprising at least two sensors, wherein the sensors are arranged and configured such that they measure a bottom dead center for the crosshead or a slide block in a particular cylinder with respect to a fixed point of the motor, the device further comprising a controller configured to: Receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an exceeded threshold indication, and wherein the controller is further configured to: re-adjust a replaced or adjusted sensor by adjusting the signals from a newly adjusted or replaced sensor Compensating the signal value according to a look-up table to compensate for operating conditions by calculating an average of an offset for the newly adjusted or replaced sensor over a period of time and offsetting the reference values for an affected sensor according to the calculated average offset.

The aspects of the disclosed embodiments further relate to providing a method of implementation in a device having a controller adapted to execute instructions stored on a physical medium, the method of monitoring wear of a crosshead bearing, a Crankpin bearing and a main bearing in a two-stroke large diesel engine, wherein the device comprises at least two sensors, wherein the sensors are arranged and configured to a bottom dead center for the crosshead or a sliding block in a particular cylinder with respect to a fixed point of Motor, the method comprising: receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining whether a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold, and wherein the method further comprises: re-adjusting a replaced or adjusted sensor by adjusting the signals from a newly adjusted or replaced sensor by compensating the sensor A signal value according to a look-up table for compensating operating conditions by calculating an average of an offset for the newly adjusted or replaced sensor over a period of time and offsetting the reference values for an affected sensor according to the calculated average offset.

The aspects of the disclosed embodiments further relate to providing a device for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a two-stroke large diesel engine, the device comprising at least two sensors, the sensors being arranged and configured such that they measure a bottom dead center for the crosshead or a sliding block in a particular cylinder with respect to a fixed point of the motor, the device further comprising a controller configured to: receive a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold, and wherein the controller is further configured to: generate trend curves indicating whether a wear has occurred during a time interval.

The aspects of the disclosed embodiments further relate to providing a method of implementation in a device having a controller adapted to execute instructions stored on a physical medium, the method of monitoring wear of a crosshead bearing, a Crankpin bearing and a main bearing in a two-stroke large diesel engine, wherein the device comprises at least two sensors, wherein the sensors are arranged and configured to have a bottom dead center for the crosshead or a sliding block of a particular cylinder with respect to a fixed point of the motor measure, the method comprising: receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold, and wherein the method further comprises: generating trend graphs indicating whether a wear has occurred during a time interval.

The aspects of the disclosed embodiments further relate to providing a motor comprising any device according to the above.

The aspects of the disclosed embodiments also relate to providing a marine vessel comprising an engine according to the foregoing.

The aspects of the disclosed embodiments further relate to providing a computer-readable medium comprising at least computer program code for monitoring wear of a bearing in a two-stroke, large diesel engine, the computer-readable medium comprising software code for executing one or a plurality of the methods of the foregoing ,

Other objects, features, advantages, and features of the apparatus, method, and computer-readable medium of the present invention are apparent from the detailed description.

Brief description of the drawings

In the following detailed section of the present description, the teachings of the present application will be explained in more detail with reference to the exemplary embodiments illustrated in the drawings, wherein: <Tb> FIG. 1 <sep> is a schematic view of a motor according to an embodiment; <Tb> FIG. Fig. 2 <sep> is a schematic view of a bearing according to an embodiment; <Tb> FIG. 3 is a flowchart describing a general method according to an embodiment; <Tb> FIG. 4 is a flow chart describing a method according to one embodiment; <Tb> FIG. Fig. 5 is a flowchart describing a method according to an embodiment; <Tb> FIG. Fig. 6 is a diagram illustrating a curve according to an embodiment; <Tb> FIG. Fig. 7 is a diagram illustrating a curve according to an embodiment; <Tb> FIG. Fig. 8 is a flowchart describing a method according to an embodiment; <Tb> FIG. 9 is a flowchart describing a method according to an embodiment; and <Tb> FIG. Fig. 10 is a diagram illustrating a curve according to an embodiment.

Detailed description

In the following detailed description, the apparatus and method according to the teachings of this invention will be described by the embodiments relating to a two-stroke, large diesel engine. It is to be noted, however, that while only a two-stroke diesel engine is described and claimed, the teachings of this application may be used in any engines, such as four-stroke engines, two-stroke gasoline engines, and two-stroke, small diesel engines.

Fig. 1 is a sectional view of an engine 100. The engine has a crankshaft with a main journal 110 and one or more crankpins 120, each connected to a crosshead 130.

At least three bearings are provided for each cylinder, a main bearing 140 (not visible in FIG. 1, indicated by a dashed line), a crankpin bearing 150 and a crosshead bearing 160.

Two sensors 170 (only one is shown) are arranged for each cylinder. In one embodiment, a sensor 170 is disposed behind the crosshead 130, and a sensor 170 is disposed in front of the crosshead 130. The sensors 170 are arranged to measure a distance between the crosshead 130 and a fixed point. Alternatively, the sensors are arranged to measure a distance between a point set at the crosshead and a fixed point.

Alternatively, the sensors are arranged to measure the distance for a sliding jaw 135.

In Fig. 1, a sensor 170 is disposed on the motor structure 100 and measures the distance to a reflective plate 175 which is attached to the sliding jaw 135. It should be noted that there are various alternatives with regard to which type of sensor is used, how it is arranged and what distance it measures.

In a preferred embodiment, the sensor 170 is disposed on the engine structure to produce the most reliable measurements when the sensor is held stationary.

In one embodiment, the sensor plate 175 is disposed on the cross-head pin to provide a measurement with reduced variation due to angular movement of the slide shoe 135.

In one embodiment, the sensors are arranged to determine the level of bottom dead center for a structure (eg, the sliding jaw, as previously described, although other structures are possible) in the motor attached to the crosshead or itself moves with it, whereby an indirect measurement of the bottom dead center is determined for the crosshead. Thus, measuring the bottom dead center level for such a structure allows determination of deviations and changes in bottom dead center levels for a crosshead.

Alternatively, the sensors 170 may be arranged differently, and may even be disposed in positions that are not in correspondence with the shaft. Preferably, however, they are arranged parallel to the shaft. Moreover, the sensors are preferably arranged axially spaced along a parallell to the shaft, as this allows determining that the wear in the main bearing 140 is.

The sensors are thus configured to provide a measurement of the lowermost level, i. of bottom dead center, for the crosshead 130 during one revolution of the motor 100.

As one skilled in the art would recognize, there are a number of alternatives for implementing a sensor 170, such as an optical proximity sensor or a capacitance-sensing proximity sensor.

Fig. 2 illustrates the general structure of a bearing 200 having a core 210 made of a hard metal, such as steel, and a sliding surface wall 220 made of a softer metal, such as white metal or tin-aluminum.

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

A controller is connected to the sensors 170 and configured to receive and process the measurements from the sensors 170 to measure the wear of the bearings. The measurement of wear is based on the fact that any change in the thickness of the bearing wall 220 in the loaded part of one of these bearings 140, 150, 160 (due to wear or seizure) will result in a corresponding change in the bottom dead center (BDC) of one or more the crossheads 130 with respect to the structure of the motor 100 leads. In the case of wear of the crankpin bearing 150 or the crosshead bearing 160, the BDC level of the respective cylinder changes, while in the case of wear of the main bearing 140, the BDC level of a sensor 170 in one cylinder and a sensor in the adjacent cylinder changes.

The signal from the sensors 170 contains a certain level of noise that affects the accuracy of the measurements of the sensors.

Another factor affecting the accuracy of the sensors is that the actual BDC level of the sliding jaw or crosshead varies slightly due to minor irregularities in the engine parameters such as ignition pressure, etc.

Another factor affecting the signal is the engine speed, i. the revolutions per minute (RPM) for the engine 100.

Another factor that affects the signal is the propeller pitch level.

Another factor that affects the signal is the load to which the engine is exposed. An example of such a load is the freight load carried by a ship.

These are all examples of engine operating conditions, and it should be noted that while the following description places emphasis on compensating for engine speeds, the teachings may be applied to compensating for the other operating conditions alone or in combination.

Other factors, such as hull deformation from varying vessel draft and engine temperature, may also have an effect on the BDC level, as can variations in the manufacturing process of various engine parts.

Factors such as signal scattering of the bearings may also have an impact on the measured BDC levels.

The method and apparatus disclosed herein are designed to take into account factors such as those mentioned above and others, and to provide a reliable measure of the wear of bearings in an engine.

FIG. 3 illustrates a flowchart for a generic method of the embodiments herein.

In a first step 310, the controller detects signals from the sensors 170. The signals are then processed by compensating various factors and corrected, 320, by calculating deviations, and the results are evaluated 330, after which it is determined whether or not a warning should be issued.

There are many factors that affect the wear of a bearing in an engine during operation. When a motor fails, it is important to isolate the source of the fault. In the case of wear of a bearing, it is important to understand the cause of the increased wear of the bearing, as a new replacement bearing would most likely be prematurely worn out as well.

As already mentioned, the use of two sensors for each cylinder allows an operator to isolate the position of the bearing being worn out.

Identifying which bearing needs to be replaced helps with the replacement because the technicians know where to open the engine and do no unnecessary work to try to find out about the bearing in question.

However, as recognized by the inventors of this application, further information may be gathered from the readings of these two sensors, which information is also useful for identifying the cause of the (increased) wear, and this allows a technician the problem to remedy and to prevent increased wear for the replacement bearing.

The further information may also be used to account for situations in which several or all of the sensors are involved without any damage being present.

As will be shown below, the extracted information may also be used to prevent a bearing from being worn out by issuing an early warning that will allow operators to eliminate the cause of the wear before the bearing wears out , which prevents engine failure and the resulting downtime for this engine.

Accordingly, the apparatus and method of this disclosure are extremely advantageous in that they can identify the cause of the increased wear and predict errors, and do so without additional sensors.

The system can therefore be easily integrated into existing motors with two sensors installed simply by connecting an upgraded controller or possibly by updating the existing controller.

The greatest influence on the BDC level has the engine speed, and the signal value received from the sensor (s) must be compensated for the engine speed or the BDC level is lower as the engine speed increases, and the Wear monitoring incorrectly signals that the bearings are worn.

Depending on the engine speed used, which depends on the engine size, there may be a variation of more than 0.3 mm in the BDC level. Therefore, a compensation of this influence is required. Since the influence on each installation is individual depending on the arrangement and orientation of the waveguide, etc., the compensation for each sensor must be set individually for each installation.

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

In one embodiment, a controller is configured to compensate for the speed based on a look-up table that includes the normal or average signal values versus speed or rpm (reference values).

The normal value may change significantly within a small change in engine speed.

In one embodiment, the look-up table has a resolution that corresponds to the division of the speed range of the rated speed of the engine into portions, hereinafter referred to as speed points.

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

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

In one embodiment, the range below 20% of the rated speed of the motor is not considered for monitoring wear in bearings.

In one embodiment, the controller is configured to take into account whether the engine is being run backwards or not.

Due to the speed compensation, the measurement taken into account by the controller is not the actual BDC level but the difference between the measured BDC level and the mean BDC level at the current engine speed. This allows detection of an abnormal or unexpected change in BDC level due to bearing wear.

Thus, the processing of the signal received by the sensor should be based on a compensated value for the signal. In one embodiment, the controller is configured to determine a compensated signal value by subtracting a reference value from the received signal value: Scomp = SN - Sref

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

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

In one embodiment, a simple filter wherein a moving average is updated for each sensor value, that is, once for each motor revolution. In one embodiment, the filter is expressed as: New filtered value = age filtered value * (1-x) + value * x

The value of x affects how quickly the controller responds to changes. A high value causes the controller to be very sensitive to changes and therefore to noise, while low values of x result in a slow response to an actual event. In one embodiment, x is 0.05.

Some factors affect all the sensors in common, and the signals received from the affected sensors may not be interpreted correctly.

One such factor is a changed engine temperature.

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

In one embodiment, the controller is configured to calculate a deviation of the signal of one sensor compared to the values of the other sensors by subtracting the average of the other signals from the single signal.

The sensor deviation (d (Si)) for sensor 5 (S5) from a total set of 8 sensors S1 to S8 (corresponding to a four-cylinder engine) can be expressed as: d (S5) = S5- (S1 + S2 + S3 + S4 + S6 + S7 + S8) / 7

Another factor is the influence of longitudinal deformation of the engine structure, which is sometimes caused by a variation of thrust forces. In some cases, this deformation causes the front and rear sensors in a cylinder to have variations in relation to each other.

By closely monitoring and inspecting engines during operation and thoroughly analyzing the results, it was concluded that the variation for the two sensors is that the signal levels are often in antiphase. This causes the signal value of one sensor to increase as the signal value for the other sensor decreases, and vice versa. This is referred to below as cylinder deviation.

In one embodiment, the controller is configured to eliminate this variation by determining an average sensor value for the two sensors of one cylinder and comparing it to the average of the sensors of the other cylinders.

The cylinder deviation (d (cyli)) for cylinder 3 (cyl3) from a total of 4 cylinders, which together comprise 8 sensors S1 to S8, can be expressed as: d (cyl3) = (S5 + S6) / 2 - (S1 + S2 + S3 + S4 + S7 + S8) / 6

Both the cylinder and sensor deviations reduce the influence of signal scattering. The cylinder deviation, however, is more efficient in reducing signal dispersion.

Therefore, calculating the cylinder deviation is useful for reducing signal dispersion.

Cylinder deviations are less sensitive to situations in which only one sensor registers damage to a bearing since the registered change would be halved during the calculation of the deviation.

Therefore, it is preferable to calculate both the cylinder and sensor deviation to allow reliable detection of damage to a bearing.

In one embodiment, a controller is configured to calculate both a cylinder and a sensor deviation.

An example of a situation in which more than one sensor is involved is when more than one bearing is damaged. This can be the result of a common erosion process that worsens several or all of the bearings. Such a situation may be the result of contaminated oil or oil supply failure.

Such a situation is not easily recognizable from the cylinder and sensor deviations, since the effects would be canceled by the averaging process of these calculations.

However, it is possible to detect such a situation from the engine speed compensated value for each signal.

In one embodiment, a controller is configured to calculate a cylinder offset, a sensor offset, and a engine speed compensated signal value.

Thus, in one embodiment according to the above, a controller is configured to extract information from the signal values considering a plurality of factors that affect the reliability of the sensor measurements.

Control of a device according to what has been said herein is thus capable of producing reliable measurements for monitoring the wear of a bearing in an engine.

In one embodiment, a controller is configured to evaluate the measurements and determine whether damage is imminent or occurring immediately.

[0110] In one embodiment, a controller is configured to compare the current measured value for a cylinder or bearing with an average value determined over a period of time. In one embodiment, the time period is 6 hours. In one embodiment, a controller is configured to determine that the difference between the current measured value and the time average is greater than a threshold level, and to activate an early warning, if so. In one embodiment, the prewarning limit is +/- 0.25 mm.

If the prewarning level is exceeded, this is an indication that the state of a monitored warehouse is changing.

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

In one embodiment, a controller is configured to receive an input to reset the prewarning action.

If it is detected that the state of the bearing has just started to change, the engine may not be at risk for at least several hours more, and it is therefore possible to reset the prewarning action and proceed with the operation of the engine ,

In one embodiment, a controller is configured to compare the current reading for a cylinder or bearing with an alarm threshold. The controller is configured to activate an alarm when such a threshold is exceeded.

An alarm is an indication that the warehouse in question is starting to wear out or is about to become worn and should be checked.

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

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

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

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

Should a major change be detected, a request may be issued to slow the engine speed. Since engine speed has the greatest impact on bearing load and bearing wear, in some situations it is possible to delay or prevent engine failure resulting from damaged bearings by slowing down the engine. In severe cases, the engine must be stopped completely to prevent a failure.

In one embodiment, a controller is configured to compare the current measured value for a cylinder or bearing with a deceleration threshold. The controller is configured to issue a request for deceleration when such a threshold is exceeded. In one embodiment, the threshold for a sensor value is +/- 0.7 mm. In one embodiment, the sensor deviation deceleration threshold is +/- 0.5 mm.

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

In one embodiment, a controller is configured to automatically stop the engine after such a deceleration request.

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

Fig. 4 illustrates a general method of monitoring the wear of a bearing according to an embodiment of the present application.

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

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

In a first step 410, a value or signal SN is received by the controller.

[0130] In one embodiment, the controller is configured to calculate a compensation value by subtracting the received signal with a reference value (420): Scomp = SN - Sref

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 (Ssensor): d (Ssensor) = Ssensor - average of other sensors

In one embodiment, the controller is also configured to calculate a cylinder deviation d (cylinder): d (cylinder) = (scylinder, front + scylinder, rear) / 2 - Mean of other sensors

In FIG. 4, both deviations are calculated in step 440.

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

In one embodiment, the controller is configured to determine if the sensor deviation alarm threshold is exceeded, 450, and activate an alarm 460, if so.

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

In Fig. 4, all three determinations are made with respect to the alarm limits, 450.

The controller is further configured such that when the controller determines that an alarm is to be activated, the controller stores 460 the event in a log file.

In one embodiment, the controller is configured to determine if a sensor deviation deceleration limit is exceeded, 480, and activate a deceleration procedure request 490, if that is the case.

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

In one embodiment, the controller is configured to execute 410-440 for each revolution.

In one embodiment, the controller is configured to execute 450 to 490 for each revolution.

In one embodiment, the controller is configured to execute 450 to 490 at intervals. In one embodiment, the interval is in the range of 1 to 50 revolutions. In one embodiment, the interval is in the range of 10 to 30 revolutions. In one embodiment, the interval is 30 revolutions. This is indicated in Fig. 4 by the dashed line.

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

In one embodiment, the controller is configured to determine whether a reference value for any engine speed is changed by a value greater than an update threshold when compared to the first received valid compensation value and an alarm indicating this activated, if this is the case. In one embodiment, the update threshold is 0.2 mm.

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

During normal operation of a two-stroke large diesel engine, the engine is set to run at an engine speed for a long period of time. During this time period, the environment of the engine is quite stable. For example, if there are no accelerations, there will be less deformation due to shear forces.

As the engine speed changes, the environment becomes less stable, which affects the BDC level of the bearings, and these BDC levels change and / or fluctuate accordingly. The controller is configured to raise the threshold levels during such time periods to accommodate such changes without sounding an alarm.

An example of another situation that affects the engine environment or operation of the engine is when the load of a ship powered by the engine increases and the ship lies deeper in the water.

The controller is configured to lower the thresholds when the operation of the engine, possibly at a new engine speed, becomes stable again.

In one embodiment, the controller is configured to lower the at least one threshold level upon expiration of a delay time. This allows the after effects of changes in the operation to be accommodated without unnecessarily alarming.

In one embodiment, two sensors are disposed in each cylinder, front and rear sensors, and as previously mentioned, the controller is configured to determine whether a main bearing or a crosshead and / or crankpin bearing is worn , To determine that a main bearing is worn or in a critical condition, the front sensor of a first cylinder is compared with the rear sensor of a second cylinder. To determine that a crosshead and / or crank pin bearing is worn or in a critical condition, the front sensor of a first cylinder is linked to the rear sensor of the same cylinder.

There are therefore two sensor readings available for the main bearing and for the crosshead and / or crankpin bearings.

In one embodiment, the controller is configured to associate the two sensor readings and compare the result of the two sensor readings to an alarm threshold level.

For an embodiment with 4 cylinders, each arranged with two sensors, giving a total of 8 sensors identified as (SF1, SA1), (SF2, SA2), (SF3, SA3), and (SF4, SA4 , where SF1 is the front sensor for cylinder 1, and SA1 is the rear sensor for cylinder 1, where cylinder 1 is the cylinder closest to the engine output (in other words, cylinder 1 is the rearmost cylinder in it) Example), is the associated sensor value SM12 for the main bearing between cylinders 1 and 2: SM12 = SF1 + SA2: and the associated sensor value SCC1 for the crosshead and / or crankpin bearing of cylinder 1 is: SCC1 = SF1 + SA1.

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

For the main bearing between cylinders 1 and 2, SM12 is then: SM12 = I SF1 - SF1ref + SA2 - SA2ref I

By comparing the sum of the two sensors, the sensitivity of the measurement is further increased because any change in the BDC level is doubled before the comparison, which is advantageous because the differences are so small.

It should be noted that the threshold levels for the alarm, the prewarning and the deceleration are not the same for individual sensor values as they are for associated sensor values.

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

During operation of the engine, a small change in BDC level is expected over time as the bearings wear out. However, these changes are very slow and difficult to distinguish from other changes, such as a changed engine environment (temperature, thrust, etc.), and the controller is configured to focus on the BDC level rather than the level change.

However, a rapid change in the BDC level may be an indication that something is going to go wrong. One such situation is when contamination has entered the oil system and the bearings wear out more quickly.

Even if the change is still within the tolerable limits (below the thresholds for the various alarms), the rate of change may result in serious damage if it is not stopped in time, and in some cases it may be too late when alarm is hit when the change is fast.

In one embodiment, the controller is configured to detect a rapid change in the BDC level by comparing the sensor values to a previous but recent level. This allows the controller to determine if there is a significant change in the last time period, even though this change is well within the tolerance limits.

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

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

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

An advantage of the exponential analysis is that it does not require storing many values and therefore is faster and more resource-friendly.

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

In one embodiment, this time period is in the interval of 1 to 20 minutes. In one embodiment, this time period is in the interval of 1 to 10 minutes. In one embodiment, this time period is in the interval of 5 to 10 minutes. In one embodiment, this time period is 10 minutes. In one embodiment, this time period is 5 minutes.

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

A controller is configured to, in one embodiment, compare the average of the last measurements to the average of sensor signals of the previous period to account for erroneous measurements and other short variations.

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

A controller is configured to, in one embodiment, compare the average of the last five measurements with the average of the previous period to account for erroneous measurements and other short variations.

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

In one embodiment, the controller is configured to determine if the difference exceeds a threshold level, and the controller is configured to issue a message to an operator if so. In one embodiment, the threshold level is 0.2 mm.

In one embodiment, the controller is configured to determine if the difference exceeds a threshold level, and the controller is configured to output a message to a log if it is.

In one embodiment, the controller is configured to determine if the difference exceeds a threshold level, and the controller is configured to sound the alarm if it does.

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

Accordingly, in such situations, an early warning may be given which may possibly prevent serious engine failure.

Detect rapid changes through exponential analysis

In one embodiment, the controller is configured to perform an exponential analysis of the sensor values and determine whether or not an alarm should be issued.

In one embodiment, the controller is configured to determine a reference level and determine a current state level by calculating exponential averages.

In one embodiment, the controller is configured to update a reference level Srefleveld by updating an old reference with a compensated value Scomp using a low-pass filter with an update factor.

In one embodiment, this is expressed as: Sreflevel, new = Sreflevel, old * (1-x) + Scomp * x where x is the update factor.

The reference level is a representation of the current normal level and should therefore respond relatively slowly. Therefore, the update factor should be chosen to be small. In one embodiment, the update factor is chosen to be 0.0001.

In one embodiment, the controller is configured to update a current state level Spres by updating an old current state with a compensated scomp using a low-pass filter with an update factor.

In one embodiment, this is expressed as: Spres, new = Spres, old * (1-y) + Scomp * y where y is the update factor.

The current state level is an illustration of the current state of the BDC level and should therefore respond 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 also calculate a reference value Srefvalue. In one embodiment, the reference value is the difference between the reference level and the current state: Srefvalue = Spres - Sreflevel

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

FIG. 9 illustrates a method for detecting rapid changes in BDC levels in warehouses using exponential algorithms according to the embodiments herein.

A signal representing a BDC level is received and compensated in steps 910 and 920 according to a table for compensation of engine operating conditions.

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

In one embodiment, the controller is configured to analyze the reference value of a single sensor to determine that a rapid change is taking place. It is determined that the rapid change takes place when the reference value exceeds a threshold. In FIG. 9, these calculations are performed in step 960.

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

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

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

In one embodiment, the threshold level for one sensor is over 110 microns.

In one embodiment, the controller is configured to analyze the sum of the reference values of sensors of a single cylinder to determine that a rapid change is taking place. It is determined that the rapid change occurs when the sum exceeds a threshold. The quick change could be in the crankpin or crosshead bearing of the cylinder. In FIG. 9, these calculations are performed in (alternative) step 940 and the determination of whether an alarm limit is exceeded or not in step 960.

Determining wear from the readings of two sensors allows a quick detection of bearing wear, since the two readings grow simultaneously and thus their sum increases twice as fast. To account for the sum being greater than the two individual sensor readings, in one embodiment, the threshold level for a sum is greater than the threshold level for a single sensor.

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

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

In one embodiment, the threshold level for sensors in a cylinder is over 160 microns.

In one embodiment, the controller is configured to analyze the sum of a reference value of a sensor from a cylinder with a reference value of a sensor in an adjacent cylinder to determine that a rapid change is taking place. It is determined that the rapid change occurs when the sum exceeds a threshold. The quick change could be in the main bearing between the two cylinders. In FIG. 9, these calculations are performed in (alternative) step 950 and the determination of whether an alarm limit is exceeded or not in step 960.

Determining wear on readings from two sensors of two different cylinders allows even faster detection of wear of a main bearing, as the two readings appear to grow faster than the sensors in the cylinder sum. This therefore provides additional security. To account for the sum growing faster than the cylinder sum, in one embodiment, the threshold level for the adjacent cylinders is greater than the threshold level for the cylinder sum.

In one embodiment, the threshold level for sensors in adjacent cylinders is 220 micrometers.

In one embodiment, the threshold level for sensors in adjacent cylinders is over 220 micrometers.

In one embodiment, the threshold level for sensors in adjacent cylinders is over 210 microns.

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

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

In one embodiment, the controller is configured to issue a deceleration request (step 970) when it is determined that a rapid change has occurred (step 965). If the changes are fast, it is important that measurements be done quickly to prevent damage, and a slowdown provides the fastest means against the rapid change.

In one embodiment, the controller is also configured to cause information about the rapid changes to be stored in a log file (step 980).

This allows a controller to respond quickly to rapid changes without having to store multiple values for each sensor and prevent further wear or damage to a bearing.

To account for variations in BDC levels due to changes in engine speed, a dynamic alarm limit or a dynamic threshold level may be used in monitoring for rapid changes.

In one embodiment, the dynamic alarm limit or the dynamic threshold level is calculated based on the change in engine speed RPM (rpm), and the dynamic threshold level increases with increasing engine speed.

In one embodiment, the controller is configured to receive an input indicative of the current or a new speed, referred to as RPMN.

[0218] The controller is configured to update a reference speed based on the new speed. In one embodiment, the controller is configured to update the reference speed by an exponential moving average, as in: RPMref, new = RPMref, old * (1-z) + RPMN * z

The controller is also configured to calculate a change in RPM, referred to as ΔRPM, by calculating the absolute value of the difference between the current speed RPMN and the reference speed: ΔRPM = | RPMN - RPMref |

In one embodiment, ΔRPM is set to be 3 rpm for all values above 3 rpm. This ensures that the alarm limit rises without becoming too high.

A base threshold level or base alarm limit, referred to as Alarm Basic, is determined as one of the thresholds listed previously, depending on which sensor combination is to be monitored (single sensor, same cylinder or adjacent cylinder).

In one embodiment, the controller is further configured to calculate a first candidate dynamic threshold level (referred to as alarm 1) based on a gain constant, referred to as k, as in: Alarm 1 = alarmbasic (1 + ΔRPM * k)

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

In one embodiment, the controller is configured to set a second candidate dynamic threshold level (referred to as Alarm 2) based on the number of engine speed measurements received since the last increase in the threshold level and designated H Gain constant, denoted as k, and a delay constant, denoted as β, calculated as in: Alarm 2 = Alarmbasic (1 + ΔRPM * k * Exp (-H / β)

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

The higher the amplification constant, the faster the alarm level rises. Examples of the gain constant are: 0.1, 0.15, 0.2, 0.25 and 0.3. In one embodiment, the gain constant is in the range of 0.05 to 0.4.

Examples of the delay constant are: 190, 200, 210. In one embodiment, the delay constant is in the range of 150 to 250.

In one embodiment, the controller is configured to determine a highest threshold level of the candidate threshold levels and to use this as the candidate dynamic threshold level: Dynamic threshold level = max (alarm 1, alarm 2).

Thus, a controller is capable of adapting to variations yet capable of detecting rapid changes in wear of a bearing.

It should be noted that the exponential analysis of the rapid changes, as previously discussed, is also suitable 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 account for all variable factors in monitoring an engine, the monitor is first calibrated during a learning phase.

The engine speed compensation look-up table must be created during a "learning process" performed by the controller.

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

[0234] In one embodiment, the controller is configured to create a speed compensation table for each sensor 170.

[0235] In the case of a wear monitoring system integrated with a newly built engine, performing a factory test or performing a test ride, it is important that the system can provide protection for the bearings from the earliest possible time. Therefore, a coarse calibration curve is created as soon as a 10-minute average of a fixed engine speed is reached. This curve is then readjusted to use three fixed engine speeds started during the learning process.

FIG. 5 illustrates a general flow chart for providing coarse calibration. The controller is configured to first make a rough estimate of engine speed compensation by approximating the table values with a BDC level vs. the engine speed created.

This rough estimate allows some control during the learning phase.

In one embodiment, the controller receives the values for each sensor at a given engine speed (or rpm), 510. The values are averaged 520, and a preliminary curve is computed from the averaged engine speed BDC level coordinate or the averaged engine speed BDC level control point and an expected change depending on the engine size across the speed range, 530. In one embodiment, the expected change is precalculated and stored in a table such as Table 1. <tb> Engine Type (Bore, cm) <sep> mm Change (20-110% RPM) <tb> 80 to 98 <sep> -0.35 <tb> 60 to 70 <sep> -0.25 <tb> Up to 50 <sep> -0.15

Table 1 Expected Change for Engine Types.

FIG. 6 illustrates a plot of a preliminary or rough estimate of the curve 600 with a mean BDC level control point 610 for a particular engine speed.

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

In one embodiment, a second speed is selected and the controller receives the values for each sensor at the second engine speed, 540. The values are averaged 550, and the curve is updated, 560, by the second averaged engine speed BDC Level coordinate or the second averaged engine speed BDC level checkpoint.

In one embodiment, the controller is configured to repeat steps 540-560 for a third speed. In Fig. 5, this is indicated by a dashed line.

In step 570, the controller finishes the coarse calibration curve (700) by interpolating between the control points (710, 720, 730) and extrapolating to cover the full engine speed range.

[0245] In one embodiment, the engine speed range is between 0 and 120%. In one embodiment, the engine speed range is between 20 and 120%.

FIG. 7 illustrates an example gross calibration curve 700 having three control points 710, 720, and 730 for the average BDC level for three engine speeds.

In one embodiment, the engine is operated at each speed for every 10 minutes. It should be noted that other operating times are also available.

In one embodiment, the controller is configured to select the three speeds shown in Table 2. <Tb> Speed number <sep> Speed <tb> 1 <sep> 20 to 50% of the rated speed <tb> 2 <sep> 50 to 80% of the rated speed <tb> 3 <sep> 80 to 100% of the rated speed

[0249] Table 2 Speeds and Corresponding Speed Intervals.

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

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

In one embodiment, the controller is further configured to receive sensor values during idle operation of the engine at various speeds and to reduce the table of BDC levels vs. VDC. Engine speeds updated.

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

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

In a first step 810, a value or signal SN is received by the controller. The controller then determines whether the compensation for the current speed is valid or not, 815.

The controller is configured to, when a predetermined number of samples of engine speed has been received, calculate a reference value for that engine speed by averaging the received samples for that sensor at that speed and generating a first valid compensation value, and Motor speed compensation table is updated.

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

The controller is configured to calculate, if it is determined that the compensation is valid, a compensation value by subtracting the received signal with a reference value (step 820): Scomp = SN-Sref

The controller is configured to calculate, if it is determined that the compensation is not valid, a compensation value by subtracting the received signal with a reference value (step 825): Scomp = SN - Sref, rough

In one embodiment, the controller is further configured to apply a filter to reduce noise in the received signal 830.

In one embodiment, the controller is configured to next calculate a sensor deviation d (Ssensor): d (Ssensor) = Ssensor average of other sensors

In one embodiment, the controller is also configured to calculate a cylinder deviation d (cylinder): d (cylinder) = (scylinder, front + scylinder, rear) / 2 - average of other sensors

In FIG. 8, both deviations are calculated in step 840.

In one embodiment, the controller is configured to determine if the alarm threshold for the sensor value is exceeded, 850, and activate an alarm, 860, if so.

In one embodiment, the controller is configured to determine if the cylinder deviation alarm threshold is exceeded, 850, and activate an alarm, 860, if so.

In one embodiment, the controller is configured to determine if the sensor deviation alarm threshold is exceeded, 850, and activate an alarm, 860, if so.

In Fig. 8, all three determinations are made with respect to the alarm thresholds in step 850.

In one embodiment, the alarm threshold for a sensor value during the learning phase is +/- 0.8 mm.

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

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

The controller is also configured such that when the controller determines that an alarm is to be activated, it stores the event in a log file 870.

In one embodiment, the controller is configured to determine whether a sensor deviation slowdown limit is exceeded 880 and activate a slowdown procedure request 890 if so.

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

[0274] In one embodiment, the controller is configured to return to step 810 to receive a new signal value.

In one embodiment, the controller is configured to execute 810-840 for each revolution.

In one embodiment, the controller is configured to execute 850 to 890 for each revolution.

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

The controller is configured to receive samples for various engine speeds over the range of available engine speeds to ensure that the entire engine range is detected during the learning phase.

[0279] In one embodiment, the controller is configured to receive samples for 100 engine speeds.

[0280] In one embodiment, the controller is configured to receive samples from each sensor for each engine speed, that is, to receive samples for each possible revolution per minute in the region of the engine.

In one embodiment, the controller is configured to determine a reference point for each speed point that was not validated during the learning phase. In one embodiment, the controller is configured to determine the reference point by interpolating from the reference values of the adjacent speed points. In one embodiment, the controller is configured to determine the reference point by extrapolating from the reference values of the coarse estimate reference points.

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

In one embodiment, the controller is configured to determine whether a reference value for any engine speed is changed by a value greater than an update threshold when compared to the first received valid compensation value and an alarm indicating this activated, if this is the case. In one embodiment, the update threshold is 0.2 mm.

In order to ensure a reliable monitoring of the wear of a bearing during an extensive learning phase, the learning phase is divided into three steps. The first step is to make a very rough preliminary estimate, which will be used as a reference for the second step in which a full rough estimate is completed. The full rough estimate is then used by the rest of the learning phase (step 3).

This ensures that the wear of bearings is monitored even during startup of the engine. This allows detection of increased wear, for example, due to faulty installations and irregularities, resulting in increased motor downtime protection for the motor.

Simple calibration could not take into account such commissioning problems, and the learning phase disclosed herein is therefore extremely advantageous.

During the life of an engine, it undergoes a series of maintenance operations and overhauls. For example, if a holder that holds the sensor (s) has been removed as a result of overhauling a main bearing. When the bracket is replaced, it is expected that the sensor (s) will be rearranged differently. There is also the possibility that a sensor must be replaced after it has been damaged or otherwise rendered inoperative. A sensor may also need to be readjusted if the mount holding the sensor is slightly bent.

This requires a readjustment of the speed compensation table or curve for one or more of the sensors.

The adjustment is made by adjusting the offset of a single sensor.

In one embodiment, the controller is configured to adjust the signals from the sensor by compensating the signal value according to the existing speed compensation look-up table or curve. During normal operation, the difference between the measured BDC level and the reference value is zero (at least in average). The compensated value therefore reflects the offset for the sensor since the absolute value of the compensated value is now greater than zero (at least on average).

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

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

However, since there is a lapse of time between sensor failure and sensor replacement and this timing may be relatively long under some circumstances, there is a risk of undetected wear on a bearing during this timeout.

The controller is configured to, in order to accommodate any such wear of a bearing, re-match based on a combination of the signals from the adjacent sensor and an average value determined over a period of time before and after the replacement. In one embodiment, the time period is 500 hours.

FIG. 10 is a plot of the speed compensation curves for two sensors, where: a1t1 + b1 is the curve for the first sensor during the 500 hours before the failure of the sensor; a2t2 + b2 is the curve for the first sensor during the 500 hours after sensor replacement; and a3t3 + b3 is the curve for the adjacent sensor during the time that the first sensor was faulty.

In these formulas, "a" denotes the slope, "t" is the time, and "b" is a constant that indicates the starting point for the curve for t = 0.

In one embodiment, the controller is configured to determine these three straight lines based on the average of compensated and filtered sensor values over 6 hours, by the least squares adjustment of the deviations.

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

[0299] After the sensor readjustment period 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, and in one embodiment, this is done by: O = O1 + a3tb + Ta2 in which: O1 is the offset during the time the sensor was defective; tb is the time during which the sensor was defective; and T is the time period (in the above embodiment, T = 500 hours).

In one embodiment, the controller is configured to preclude a replaced sensor from calculating sensor deviation and / or cylinder deviation for the other sensors during the period of time after replacement of the sensor or the time period of retuning for the sensor.

In one embodiment, the controller is configured not to calculate a sensor deviation and / or cylinder deviation for a replaced sensor during the time period of retuning for the sensor.

In one embodiment, the controller is configured to refrain from activating an alarm or issuing a sensor value slowdown request that results from the replaced sensor during the time period of retuning.

This allows a learning phase only for the affected or replaced sensor and does not require a complete repetition of the learning phase for all sensors. This allows for safer monitoring during the readjustment phase, as there would have been a complete repetition of the learning phase for all sensors.

The data storage in the warehouse wear monitoring system serves two purposes. The first purpose is to be able to retrieve the data if bearing damage has occurred. In one embodiment, this is implemented as a "black box" function.

The second purpose is related to the testing of the bearings. Traditionally, bearings are opened for routine testing on a schedule. For example, every warehouse has to be opened in, say, four- or five-year intervals. In order to avoid unnecessary opening of the bearings, it is desirable to move from time-based tests to condition-based tests. For this purpose, the stored data can be used to generate trend curves that show whether wear has occurred during the test interval. Such curves can be presented to a classification surveyor.

In one embodiment, the controller is configured to allow storage for each sensor of filtered values timestamps available from the last 24 hours. In one embodiment, such filtered values are stored in a temporary memory. In one embodiment, a set of data is required for every 30 engine revolutions. A controller is configured to separately store a copy of the short term memory as a "frozen" copy if an alarm limit is exceeded. In one embodiment, the controller is configured to place data in the copy for 5 minutes after the time of the alarm.

In one embodiment, the controller is configured to allow storage for each sensor of filtered maximum, minimum, and average values. In one embodiment, such filtered maximum, minimum and average values are stored in a long term memory. In one embodiment, the filtered maximum, minimum, and average values are stored for every 6 hours of operation. In one embodiment, the filtered maximum, minimum and average values are stored with a time stamp.

In one embodiment, an event log is also stored. In one embodiment, an event log contains the following information: Any alarms, slowdowns or alerts that are issued, or changes during the learning process; possible replacement and / or offset adjustments of any sensors; Changes the sensor reference from coarse calibration to fine calibration; and all resets of the alert alert level.

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

In one embodiment, a device for downloading stored data and event logs to an external device such as a personal computer is configured. These data may serve the purpose of the submission before surveyors of classification societies.

[0312] In one embodiment, the data includes: Motor piece of information. This contains information about the ship and the engine. In one embodiment, the information is as follows. <tb> Name of the vessel <sep> = <sep> xxxxxxx <Tb> IMO number <sep> = <sep> xxxxxxx <tb> Classification Register No. <sep> = <sep> xxxxxxx <Tb> Component <sep> = <sep> xxxxxxx <Tb> Engine licensors <sep> = <sep> xxxxxxx <Tb> Engine Manufacturer <sep> = <sep> xxxxxxx <Tb> Engine Type <sep> = <sep> xxxxxxx <Tb> Motor-Ser. <Sep> = <sep> xxxxxxxx <Tb> CM system type <sep> = <sep> bearing wear monitoring system <Tb> CM system producer <sep> = <sep> XXXXXXXX <Tb> CM-system hardware <sep> = <sep> xxxxxx <Tb> CM system software <sep> = <sep> xxxxxxx <tb> Trend data period from <sep> = <sep> YYYY-MM-DD <tb> Trend data period until <sep> = <sep> YYYY-MM-DD <tb> engine operating hours from <sep> = <sep> 99999 <tb> engine operating hours to <sep> = <sep> 99999

[0313] The log part with all changes to the system status and sensor status according to the event log. The format is [DATE] [TIME] [EVENT].

[0314] Trend part filtered values. Derived from "long-term storage". The following data should be displayed for each sensor every six engine hours of operation: timestamp, engine operating hours and filtered 6-hour averages. The format is in one embodiment [DATE AND TIME: YYYY-MM-DD hh: mm: ss]; [ENGINE HOURS: h]; [DISTANCE: mm].

[0315] Status part. The purpose of this file is to provide a quick overview of each cylinder to show whether opening the bearings with respect to that cylinder is warranted for verification due to detected wear or other circumstances. These circumstances could be a detection of wear exceeding the "significance limit" during a sensor replacement, or a loss of reference. In one embodiment, the status is displayed as a representation on four levels. The four levels are: Normal «N» indicates that no wear was detected beyond the prewarning limit; Prewarning «W», indicates that wear beyond the prewarning limit has been detected; Alarm «A» indicates that an alarm has been triggered by sensors connected to this cylinder; and Unknown "U", indicates that a sensor of this cylinder has lost reference or that its reference curve has been corrected due to wear detected by its "neighbor" during the replacement. The same indication must be given if a damaged sensor remains unchanged.

In one embodiment, an apparatus is also configured to provide the full data of the long term memory, the short term memory and the reference curves of each sensor.

The various aspects of what has been previously described may be used alone or in various combinations. The teachings of this application may be implemented by a combination of hardware and software, but may also be implemented in hardware or software. The teachings of this application may also be implemented as computer readable code on a computer readable medium.

The teaching of the present invention has numerous advantages. Various embodiments or implementations may yield one or more of the following advantages. It should be noted that this is not an exhaustive list and that there may be other benefits not described herein. For example, an advantage of the teachings of this application is that a device as set forth herein provides reliable monitoring that accounts for multiple (external) factors.

[0319] Another exemplary advantage of the teaching of the present application is that wear monitoring accommodates deformation caused by shear forces.

Another exemplary advantage of the teaching of the present application is that the monitoring of wear in bearings is also reliable during a calibration phase.

Another exemplary advantage of the teachings of the present application is that replacement of a sensor can be more reliably performed and adjusted.

It goes without saying that, despite the desire in the preceding specification to focus on those features of the invention which are believed to be particularly important, the Applicant is under the claims protection with respect to all patentable features or combinations of features claimed hereinbefore and / or illustrated in the drawings, whether or not they have been particularly emphasized.

[0323] The term "comprising" as used in the claims does not exclude other elements or steps. The term "on" or "an" as used in the claims does not exclude a plurality. A unit or other means may perform the functions of several units or means mentioned in the claims.

As part of a summary and supplement, the claims defined in the priority application are listed and numbered hereto as part of the disclosure in order to allow the various points of the invention illuminated herein to be inter-related. The invention relates on the one hand to devices and on the other hand to methods, namely:

An apparatus for monitoring wear of a crosshead bearing, a crankpin bearing, and a main bearing in a two-stroke large diesel engine, the apparatus comprising at least two sensors, the sensors being arranged and configured to have a bottom dead center level in one measure certain cylinder with respect to a fixed point of the engine, the device further comprising a controller configured to: Receiving a signal from each sensor; Compensating each signal in response to an operating condition; Determining a deviation to account for factors affecting the sensor signal; Determining if a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold.

2. The apparatus of item 1, wherein the controller is configured to determine a sensor deviation for each sensor based on the received sensor values to determine the deviation of each sensor from the average of the other sensors.

3. The apparatus of item 1, wherein the engine further comprises at least one cylinder, and the controller is further configured to determine a cylinder deviation for each cylinder based on the received sensor values by determining the deviation of the sensor values from each individual cylinder from the average of the sensor values of the other sensors.

4. The device of item 1, wherein the controller is configured to determine whether a threshold is exceeded by comparing a threshold to a compensated sensor value.

5. The device of item 1, wherein the controller is configured to determine whether a threshold is exceeded by comparing a threshold with a deviation.

6. The device of items 2 and 5, wherein the controller is configured to determine whether a threshold is exceeded by comparing a threshold to a sensor deviation.

7. The device of items 3 and 5, wherein the controller is configured to determine whether a threshold is exceeded by comparing a threshold to a cylinder deviation.

8. The device of item 1, wherein a threshold corresponds to one taken from a group comprising an alert, an alarm, and a slowdown.

9. The device of item 1, wherein the operating condition is an engine speed.

10. The device of item 1, wherein the operating condition is a propeller pitch level.

11. The device of item 1, wherein the operating condition is a load.

[0336] 12. A method of implementation in a device having a controller adapted to execute instructions stored on a physical medium, the method for monitoring wear of a crosshead bearing, a crankpin bearing, and a main bearing in a two-stroke cycle. A large diesel engine, the apparatus comprising at least two sensors, the sensors being arranged and configured to measure a level of bottom dead center in a particular cylinder with respect to a fixed point of the engine, the method comprising: Receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining a deviation to account for factors affecting the sensor signal; Determining if a threshold has been exceeded and outputting, if so, an indication of the exceeded threshold.

13. A device for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a two-stroke large diesel engine, the device comprising at least two sensors, wherein the sensors are arranged and configured to a level of bottom dead center in a measure certain cylinders with respect to a fixed point of the engine, the device further comprising a controller configured to: receive a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an exceeded threshold indication, and wherein the controller is further configured to: dynamically changing the threshold according to the current operation of the engine.

14. The device of item 13, wherein the controller is configured to detect that an operating condition is changing and to raise the threshold level in response thereto.

15. The device of item 13, wherein the operating condition is an engine speed.

16. The device of item 13, wherein the operating condition is a propeller pitch level.

17. The device of item 13, wherein the operating condition is a load.

18. The apparatus of item 14, wherein the controller is configured to determine that the operating condition is not changing, and in response, to lower the threshold level.

19. The device of item 21, wherein the controller is configured to lower the threshold level after a delay time has elapsed since the operating condition changed.

[0344] 20. A method of implementation in a device having a controller adapted to execute instructions stored on a physical medium, the method for monitoring wear of a crosshead bearing, a crankpin bearing, and a main bearing in a two-stroke cycle. A large diesel engine, the apparatus comprising at least two sensors, the sensors being arranged and configured to measure a level of bottom dead center in a particular cylinder with respect to a fixed point of the engine, the method comprising: Receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an exceeded threshold indication, and wherein the method further comprises: dynamically changing the threshold according to the current operation of the engine.

21. A device for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a two-stroke large diesel engine, the device comprising at least two sensors, wherein the sensors are arranged and configured to a level of bottom dead center in a certain cylinders with respect to a fixed point of the engine, and wherein the at least two sensors are arranged so that there are two sensors in each cylinder, a front and a rear sensor, wherein the device further comprises a controller configured to: Receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an exceeded threshold indication, and wherein the controller is further configured to: Determining that a main bearing is worn or in a critical state by linking the front cylinder first sensor signal to the second cylinder rear sensor signal and / or determining that a main bearing is worn or in a critical condition by linking the signal of the front sensor of a first cylinder with the signal of the rear sensor of the same cylinder and comparing the result of the two sensor signals with the threshold level.

22. The apparatus of item 21, wherein the controller is configured to compare a linked signal value to a doubled threshold level.

23. The device of item 21, wherein the operating condition is an engine speed.

24. The device of item 21, wherein the operating condition is a propeller pitch level.

25. The device of item 21, wherein the operating condition is a load.

[0350] 26. A method of implementation in a device having a controller adapted to execute instructions stored on a physical medium, the method for monitoring wear of a crosshead bearing, a crankpin bearing, and a main bearing in a two-stroke cycle. A large diesel engine, the apparatus comprising at least two sensors, the sensors being arranged and configured to measure a level of bottom dead center in a particular cylinder with respect to a fixed point of the engine, the method comprising: Receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an exceeded threshold indication, and wherein the method further comprises: Determining that a main bearing is worn or in a critical condition by comparing the front sensor signal of a first cylinder with the rear sensor signal of a second cylinder and / or determining that a main bearing is worn or in a critical condition by comparing the signal of the front sensor of a first cylinder with the signal of the rear sensor of the same cylinder and linking the two sensor signals and comparing the result of the two sensor signals with the threshold level.

27. An apparatus for monitoring wear of a crosshead bearing, a crankpin bearing, and a main bearing in a two-stroke, large diesel engine, the apparatus comprising at least two sensors, the sensors being arranged and configured to have a bottom dead center in one measure certain cylinder with respect to a fixed point of the engine, the device further comprising a controller configured to: Receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an exceeded threshold indication, and wherein the controller is further configured to: Detecting a rapid change in the bottom dead center level by comparing the received sensor signals with a mean level of sensor signals for a previous period of time.

28. The device of item 27, wherein the time period being compared precedes the measured sensor values by a second time period.

29. The device of item 27, wherein the controller is configured to compare the average of a set of received sensor signals with the mean level of the previous time period.

30. The apparatus of item 27, wherein the controller is configured to determine a rate of change from the difference between the mean level of a previous time period and the current level.

31. The device of item 27, wherein the operating condition is an engine speed.

[0356] 32. The device of item 27, wherein the operating condition is a propeller pitch level.

[0357] 33. The device of item 27, wherein the operating condition is a load.

[0358] 34. A method of implementing in a device having a controller adapted to execute instructions stored on a physical medium, the method of monitoring wear of a crosshead bearing, a crankpin bearing, and a main bearing in a two-stroke A large diesel engine, the apparatus comprising at least two sensors, the sensors being arranged and configured to measure a level of bottom dead center in a particular cylinder with respect to a fixed point of the engine, the method comprising: Receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an exceeded threshold indication, and wherein the method further comprises: Detecting a rapid change in BDC level by comparing the received sensor signal with a mean level of sensor signals for a previous time period.

35. An apparatus for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a two-stroke large diesel engine, the device comprising at least two sensors, the sensors being arranged and configured to have a bottom dead center level in one measure certain cylinder with respect to a fixed point of the engine, the device further comprising a controller configured to: Receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an exceeded threshold indication, and wherein the controller is further configured to: Detecting a rapid change of a bottom dead center level by updating a reference level for a sensor; Updating a current level for a sensor and determining a reference value and determining whether the reference value exceeds a threshold level of rapid change.

[0360] 36. The device of item 35, wherein the controller is configured to update the reference level based on an exponential moving average.

[0361] 37. The device of item 36, wherein an exponential moving average update factor indicates a slow update.

[0362] 38. The device of item 35, wherein the controller is configured to update the current level based on an exponential moving average.

[0363] 39. The device of item 38, wherein an exponential moving average update factor indicates a fast update.

40. The device of item 35, wherein the reference value is the difference between the reference level and the current level for a sensor.

[0365] 41. The apparatus of item 36, wherein the reference value is a sum of the difference between the reference level and the current level for a sensor associated with a cylinder and the difference between the reference level and the current level for the other sensor, which belongs to the same cylinder.

[0366] 42. The apparatus of item 35, wherein the reference value is a sum of the difference between the reference level and the current level for a sensor associated with a cylinder and the difference between the reference level and the current level for the other sensor, which belongs to a neighboring cylinder.

[0367] 43. The device of item 35, wherein the operating condition is an engine speed.

[0368] 44. The device of item 35, wherein the operating condition is a propeller pitch level.

[0369] 45. The device of item 35, wherein the operating condition is a load.

[0370] 46. The device of item 35, wherein the fast change threshold level is dynamic.

47. The device of item 35, wherein the controller is configured to determine the dynamic threshold level based on a change in engine speed.

48. The apparatus of item 47, wherein the controller is further configured to determine the dynamic threshold level based on a change in engine speed compared to a reference speed, wherein the reference speed is an exponential moving average of engine speeds.

49. The device of item 48, wherein the controller is further configured to determine the dynamic threshold level based on a change in engine speed and a boosting constant.

50. The device of item 48, wherein the controller is further configured to adjust the dynamic threshold level based on a change in engine speed, a deceleration constant, a number of received engine speeds since a last determination of a fast change threshold level and a boosting constant certainly.

[0375] 51. The device of item 35, wherein the engine is a two-stroke large diesel engine.

52. A method of monitoring wear of a crosshead bearing, a crankpin bearing, and a main bearing in an engine, the device comprising at least two sensors, the sensors being arranged and configured to sense a bottom dead center level in a particular cylinder with respect to a fixed point of the engine, the device further comprising a controller configured to: Receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an exceeded threshold indication, and wherein the controller is further configured to: Detecting a rapid change of a bottom dead center level by updating a reference level for a sensor; Updating a current level for a sensor and determining a reference value and determining whether the reference value exceeds a threshold level of rapid change.

53. An apparatus for monitoring wear of a crosshead bearing, a crankpin bearing, and a main bearing in a two-stroke, large diesel engine, the apparatus comprising at least two sensors, the sensors being arranged and configured to have a bottom dead center level in one measure certain cylinders with respect to a fixed point of the engine, the device further comprising a controller configured to: receive a signal from each sensor; Compensating each signal in response to an engine operating condition; and wherein the controller is further configured to: Re-adjusting the compensation for a sensor by adjusting the signals from a sensor by compensating the signal value according to a look-up table to compensate for operating conditions by calculating an average of an offset for the sensor over a period of time and offsetting the reference values for an affected sensor according to the calculated average offset.

54. The device of item 53, wherein the controller is configured to base the retuning on a combination of the signals from an adjacent sensor and an average value determined over a period of time before and after the event that caused the retuning required.

[0379] 55. The device of item 53, wherein the controller is configured to use the table to compensate for operating conditions for an adjacent sensor when re-fitting the sensor.

[0380] 56. The device of item 53, wherein the controller is further configured to calculate an offset (0) for the sensor after a time period for re-adjusting the sensor has elapsed, wherein the controller is configured to set the sensor Offset for the sensor calculated by: O = O1 + a3tb + Ta2 in which O1 is the offset during the time the sensor was defective; tb is the time during which the sensor was defective; and a2 is the slope of a curve that corresponds to the values of a table to compensate for operating conditions during the retuning period, a3 is the slope of a curve corresponding to the values of a table for compensating operating conditions for an adjacent sensor, and T is the time period for re-fitting the sensor.

[0381] 57. The apparatus of item 54, wherein the controller is configured to send a sensor for calculating the sensor deviation and / or cylinder deviation for the other sensors during the time period after the event that required the time period of readjustment for the sensor, excludes.

58. The device of item 53, wherein the operating condition is one of an engine speed, a propeller pitch level, and a load.

[0383] 59. A method of implementing in a device having a controller adapted to execute instructions stored on a physical medium, the method of monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a two-stroke A large diesel engine, the apparatus comprising at least two sensors, the sensors being arranged and configured to measure a level of bottom dead center in a particular cylinder with respect to a fixed point of the engine, the method comprising: Receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an exceeded threshold indication, and wherein the method further comprises: Re-adjusting the compensation for a sensor by adjusting the signals from a sensor by compensating the signal value according to a look-up table to compensate for operating conditions by calculating an average of an offset for the sensor over a period of time and offsetting the reference values for an affected sensor according to the calculated average offset.

60. An apparatus for monitoring wear of a crosshead bearing, a crankpin bearing, and a main bearing in a two-stroke large diesel engine, the apparatus comprising at least two sensors, the sensors being arranged and configured to have a bottom dead center level in one measure certain cylinders with respect to a fixed point of the engine, the device further comprising a controller configured to: receive a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an exceeded threshold indication, and wherein the controller is further configured to: Generating trend curves that show if a wear occurred during a time interval.

61. The device of item 60, wherein the controller is configured to store filtered values with a time stamp for each sensor in a short term memory and store filtered maximum, minimum and average values for each sensor in a long term memory.

[0386] 62. The device of item 60, wherein the controller is configured to determine if an alarm limit is exceeded and to store a copy of the short term memory in a long term memory if that is the case.

63. The device of item 62, wherein the controller is configured to capture data into the copy for 5 minutes after the time of the alarm.

64. The device of item 60, wherein the controller is further configured to store the filtered maximum, minimum and average values every six hours of operation.

[0389] 65. A method of implementing in a device having a controller adapted to execute instructions stored on a physical medium, the method for monitoring wear of a crosshead bearing, a crankpin bearing, and a main bearing in a two-stroke A large diesel engine, the apparatus comprising at least two sensors, the sensors being arranged and configured to measure a level of bottom dead center in a particular cylinder with respect to a fixed point of the engine, the method comprising: Receiving a signal from each sensor; Compensating each signal in response to an engine operating condition; Determining if a threshold has been exceeded and outputting, if so, an exceeded threshold indication, and wherein the method further comprises: Generating trend curves that show if a wear occurred during a time interval.

[0390] 66. Engine comprising a device according to item 1, 13, 21, 27, 53 or 60, wherein the engine is a two-stroke large diesel engine for ships.

67. Seagoing vessel comprising a motor according to one of the points 51 or 66.

The articles for which protection is claimed are defined in the following claims.

Claims (15)

An apparatus for monitoring wear of a crosshead bearing, a crankpin bearing and a main bearing in a two-stroke large diesel engine, the apparatus comprising at least two sensors and a controller configured to process the signals provided by the sensors, the sensors being arranged and are configured to measure a level of bottom dead center for the crosshead or a sliding block in a particular cylinder with respect to a fixed point of the engine, the controller being further configured to acquire in a learning phase a table of reference values to compensate for engine operating conditions and that is also configured for normal operation for: Receiving a signal from each sensor; Compensating each signal with a reference value depending on the respective engine operating condition; and Determining if a threshold has been exceeded and, if so, outputting an exceeded threshold indication. 2. The apparatus of claim 1, wherein the controller is configured to determine the reference values in the learning phase and store them in the table by: Sampling a first number of sensor values with respect to a second number of engine operating conditions during operation of the engine, and Determining, when the first number of samples for an engine operating condition has been received, determining a reference value by averaging the received samples for that engine operating condition point. 3. The apparatus of claim 1, wherein the controller is configured to determine and store in the table the reference values in the learning phase, namely, in a first phase, receiving signal values from at least one sensor over a period of time for a first engine operating condition; Averaging the signal values to produce a first reference value; and in a second phase with other engine operating conditions, each further engine operating condition comprising the steps of: Receiving signal values from the at least one sensor and generating an associated reference value by averaging the received signal values, Estimating a compensation value using the first reference value as a coarse calibration by determining the compensation value by extrapolating the reference value using a predetermined estimated change factor, Compensating the reference value associated with the current engine operating condition with the estimated compensation value; and Determining if a threshold has been exceeded and, if so, outputting an exceeded threshold indication. 4. The apparatus of claim 1, wherein in the learning phase the controller is configured to determine the reference values in two phases and store them in the table, namely, in a first phase, receiving signal values from the at least one sensor over a period of time and generating a reference value by averaging the received signal values for a predetermined fixed number of engine operating conditions; and in a second phase with other engine operating conditions, each further engine operating condition comprising the steps of: Receiving signal values from the at least one sensor and generating an associated reference value by averaging the received signal values, Estimating a compensation value using already determined reference values as a coarse calibration by comparing the compensation value by interpolating between the reference values of two adjacent engine operating conditions when the current engine operating condition is within the range of engine operating conditions already being performed and extrapolating the reference value using a predetermined estimated variation factor if the current engine operating condition is outside the range of engine operating conditions already in operation, it is determined Compensating the reference value associated with the current engine operating condition with the estimated compensation value; and Determining if a threshold has been exceeded and, if so, outputting an exceeded threshold indication. 5. The apparatus of claim 1, wherein the operating condition is an engine speed and the engine operating condition point is a speed point. 6. Device according to one of claims 1 to 4, wherein it is at the operating condition to a propeller pitch level. 7. Device according to one of claims 1 to 4, wherein it is a load in the operating condition. 8. The apparatus of claim 4, wherein the fixed number of engine operating conditions of the first phase of the learning phase is three, wherein the engine operating condition is an engine speed and the engine operating condition point is a speed point, and wherein the three engine speeds are: a first engine speed taken from the range of 20 to 50% of a rated engine speed; a second engine speed taken from the range of 50 to 80% of the rated engine speed; and a third engine speed taken from the range of 80 to 100% of the rated engine speed. 9. The apparatus of claim 1, wherein the controller is further configured to redetermine the reference value for at least one engine operating condition point in a time interval and to update the engine operating condition compensation table with the new reference value. 10. The apparatus of claim 9, wherein the controller is further configured to determine whether the new reference value for an engine operating condition point is changed by a factor compared to the old reference value and to activate an alarm if it is. 11. The apparatus of claim 8, wherein the controller is further configured to update the table to compensate for engine operating conditions after the learning phase by interpolating and extrapolating between values of the engine operating condition compensation table. 12. The device of claim 1, comprising more than two sensors, wherein the controller is configured to determine a sensor deviation for each sensor based on the received sensor values to determine the deviation of each sensor from the average of the other sensors , 13. An engine comprising an apparatus according to any one of claims 1 to 12, wherein the engine is a two-stroke large diesel engine for ships. 14. seagoing vessel comprising an engine according to claim 13. 15. A method of monitoring wear of a crosshead bearing, a crankpin bearing, and a main bearing in a two-stroke, large diesel engine comprising a learning phase in which a table of reference values for compensating engine operating conditions is generated and a phase for normal operation comprising the steps of: Receiving a signal from at least two sensors arranged and configured to measure a level of bottom dead center for the crosshead or a sliding jaw in a particular cylinder with respect to a fixed point of the engine; Compensating each signal with a reference value in response to the current engine operating condition; Determining if a threshold has been exceeded and, if so, outputting an exceeded threshold indication.