JP2010007672A - Method for detecting abnormality of diesel engine for marine use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a sliding abnormality between a cylinder 2 and a piston 3 in a marine diesel engine 1 and to install a gas temperature detector by an inexpensive and easy construction method and to perform an effective abnormality detection. provide.
A temperature detector (10) is installed near a scavenging port (7) through a scavenging chamber outer wall (11). The detector 10 makes an abnormality determination by directly measuring the high-temperature gas leaked when the cylinder 2 and the piston 3 slide abnormally. In addition, the scavenging tube temperature detector 12 can be installed so that it can respond to changes in the outside air temperature, or the reference value corresponding to the engine load can be further incorporated into the determination to improve the accuracy of the abnormality determination. it can.
[Selection] Figure 3

Description

  The invention according to claim relates to an abnormality detecting device for detecting a sliding abnormality such as blow-by and scuffing in a sliding portion between a cylinder and a piston in a marine two-cycle diesel engine.

  In the operation of a diesel engine, a sliding abnormality such as seizure may occur between the cylinder and the piston in the case of poor combustion due to the use of poor fuel oil or the like. Sliding abnormalities not only cause a decrease in output, but also cause damage to cylinders and pistons, which may make it impossible to operate the engine.

  Conventionally, there is a document shown below for detecting a sliding abnormality between a cylinder and a piston. That is, in Patent Documents 1 and 2 and Non-Patent Documents 1 and 2, a technique for detecting the occurrence of abnormal sliding by sensing a rise in the outer wall temperature with a temperature detector embedded in the outer wall of the cylinder liner (or cylinder). Is described.

In patent document 1, the detection signal in the 1st temperature detector installed in the position which does not receive the influence of abnormality very much and the 2nd temperature detector which detects the high temperature produced at the time of abnormal friction generation are compared, and the result is a normal state. The abnormal temperature detection apparatus which judges as abnormal when different is shown.
Non-Patent Document 2 discloses an apparatus for detecting abnormality of temperature by detecting a temperature pattern that appears as a sign in order to detect scuffing (abnormal wear of a cylinder) at an early stage.
In any of the techniques described in any of the documents, abnormal wear between the cylinder and the piston is detected by a temperature detector incorporated in the outer wall of the cylinder liner to determine an abnormal state. In Patent Document 1, there is a portion described as “detecting a high-temperature combustion gas temperature”, but the temperature measured by a temperature detector embedded in the outer wall is merely handled as the temperature of the combustion gas.

Japanese Patent Laid-Open No. 60-32941 Japanese Patent Laid-Open No. 7-198544

Journal of the Japan Marine Engineering Society Vol. 38, No. 12 (2003-12) "Cause of Scuffing in Diesel Engine Cylinder Liners, Predictive Diagnosis and Preventive Maintenance" Journal of Japan Marine Engineering Vol.41, No.6 (2006) “T-MAS to detect scuffing before excessive wear occurs”

In the methods described in the above-mentioned documents, it is necessary to make a hole in the outer wall of the cylinder liner. However, the cylinder liner outer wall has a high stress level during operation of the diesel engine, requires special consideration for drilling, and the cost required for machining is also high.
Moreover, in the technique of each said literature, since the temperature of the metal part of an outer wall is detected, the gas temperature cannot be detected directly. Therefore, it is difficult to detect the blow-by phenomenon (gas leakage from between the piston ring and the cylinder liner) based on a seal failure due to abnormal wear of the piston ring installed around the piston.
The above technique is not preferable in terms of durability of the detector. That is, since the cylinder liner part is a part that directly receives the explosive force, the detector embedded in the cylinder liner part is always subjected to a large vibration, and the durability tends to decrease.

  The claimed invention has been made in consideration of the above points, facilitates the processing necessary for mounting the temperature detector, enables detection of blow-by, and improves the durability of the detector. An abnormality detection method for a marine diesel engine that can also be provided is provided.

The abnormality detection device for a marine diesel engine according to the invention may include a scavenging port temperature detector that detects a gas temperature in the vicinity of the scavenging port in the scavenging chamber.
When blow-by occurs due to abnormal wear of the cylinder liner or piston ring, the gas temperature near the scavenging port rises due to the hot gas leaking from the scavenging port. According to this abnormality detection device, the high temperature gas leaking to the vicinity of the scavenging port by blow-by can be directly detected by the temperature detector (scavenging port temperature detector) installed in the vicinity of the scavenging port. Since blow-by always occurs in the initial stage before scuffing occurs, scuffing can also be detected in advance by detecting blow-by in this way.
Moreover, in this abnormality detection apparatus, since it is not necessary to embed a temperature detector in the cylinder liner outer wall which is difficult to process, the processing cost for installing the detector can be reduced. Since it is away from the cylinder liner which is the largest vibration source of the diesel engine, it is desirable also from the viewpoint of durability of the temperature detector.

The abnormality detection device may be attached by the scavenging port temperature detector being inserted into a hole provided in the wall of the scavenging chamber from the outside of the wall and fixed outside the wall. .
Because the temperature detector is attached to a hole provided in the wall of the scavenging chamber where a more general material is used rather than to the outer wall of the cylinder liner, which is difficult to process, Costs are particularly reduced. Since the temperature detector is attached in such a manner that it is inserted from the outside of the wall of the scavenging chamber and fixed on the outside of the wall, its attachment and removal are also easy. It is the same as the above-described apparatus relating to the invention that the detector can directly detect the high-temperature gas that leaks out in the event of an abnormality and is also preferable in terms of durability of the detector. If there is an open / close hatch for inspection near the scavenging port, it is also preferable to install a temperature detector on the hatch as the wall of the scavenging chamber.

The abnormality detection device may include a determination unit that receives a signal from the scavenging port detector and generates an abnormality signal when a temperature indicated by the signal exceeds a reference value.
By using such a determination device (for example, a temperature abnormality determination device described later), abnormality determination that does not depend on human judgment can be performed, and determination accuracy is improved.

An abnormality detection device related to the invention includes a scavenging port temperature detector that detects a gas temperature in the vicinity of the scavenging port in a scavenging chamber, and a scavenging tube temperature detector that detects a gas temperature in the scavenging tube, and detects the temperature thereof. It is preferable to have a determiner that receives the signal of the detector and emits an abnormal signal when the difference in temperature indicated by the signals of both temperature detectors exceeds a reference value.
According to this, the above-mentioned detection can be made more accurate by correcting the influence of the outside air temperature due to the operation area, the weather, or the like.
In other words, a ship equipped with an engine sails over a wide area, and there are areas where the outside air temperature is high and low, and the weather changes greatly. When the outside air temperature rises, the scavenging tube temperature rises accordingly, and the scavenging port temperature also rises accordingly. Therefore, it may be difficult to determine that the scavenging port temperature has risen due to the blow-by phenomenon only by increasing the scavenging port temperature.
Therefore, in this detection device, by providing a scavenging tube temperature detector that detects the gas temperature in the scavenging tube, the difference between the scavenging port temperature and the scavenging tube temperature is taken, and the range of change of this temperature difference from the normal state is determined as a judgment condition. And Then, when the scavenging port temperature rises, it can be determined with higher accuracy whether it is due to blow-by, that is, due to abnormal cylinder sliding or simply due to a rise in outside air temperature.

In the abnormality detection device related to the invention, a scavenging port temperature detector for detecting a gas temperature in the vicinity of the scavenging port in the scavenging chamber, a scavenging tube temperature detector for detecting a gas temperature in the scavenging tube, and an engine load are detected. A load detector and a signal of the temperature detector and the load detector, and a difference in temperature indicated by the signals of the two temperature detectors is associated with an engine load indicated by the signal of the load detector. It is preferable to have a determination device that emits an abnormal signal when the reference value is exceeded. A dynamometer can be used as a load detector, but a turbocharger speed detector or a governor rack position detector is used, and the turbocharger speed or the governor rack position detected by them is detected by the engine. It may be replaced with a load.
In this abnormality detection device, it is possible to further improve the determination and judgment in consideration of the fact that the combustion gas temperature changes according to the load of the diesel engine as follows.
In a diesel engine, the combustion chamber gas temperature generally increases as the operating load increases. Therefore, when the temperature difference between the scavenging port temperature detector and the scavenging pipe temperature detector output exceeds the value that is standardized by the operational load state of the ship, it is determined that there is an abnormality, thereby detecting the detected temperature difference. It is possible to determine whether the increase of is due to abnormal cylinder sliding or simply due to a change in engine load. Since the determination is made based on the temperature difference between the scavenging port temperature and the scavenging pipe temperature, it goes without saying that it can be prevented from being affected by changes in the outside air temperature.

The marine diesel engine relating to the invention is preferably provided with the above-described abnormality detection device.
In such an engine, the above-described preferable abnormality detection can be performed while suppressing the cost required for mounting the temperature detector.

An abnormality detection method for a marine diesel engine related to the invention detects a scavenging port temperature that is a gas temperature in the vicinity of the scavenging port in a scavenging chamber, or further detects a scavenging tube temperature that is a gas temperature in the scavenging tube. When the scavenging port temperature exceeds the reference value, or when the temperature difference between the detected scavenging port temperature and the scavenging tube temperature exceeds the reference value, it is preferable to make an abnormality.
This method can be implemented using the above-mentioned apparatus, for example, a) abnormal wear of a cylinder liner or the like can be detected from the blow-by stage, b) a cylinder liner made of a special material to detect temperature For example, it is not necessary to perform a difficult process to attach a temperature detector, and c) it is possible to improve the durability of the means for detecting the temperature. In addition, if the temperature of the scavenging tube is also detected and the temperature difference between the detected scavenging port temperature and the scavenging tube temperature exceeds the reference value, it will be abnormal. Thus, it is possible to detect an abnormality with higher accuracy.

The abnormality detection method related to the invention is to detect a scavenging port temperature that is a gas temperature in the vicinity of a scavenging port in a scavenging chamber, a scavenging tube temperature that is a gas temperature in the scavenging tube, and an engine load. It is preferable that an abnormality occurs when the temperature difference between the temperature and the scavenging tube temperature exceeds a reference value associated with the detected engine load.
In this way, in addition to the merits of the above method, it is possible to correct the influence of the temperature change due to the engine load and perform more accurate abnormality detection.

In addition to the above method, the abnormality detection method related to the invention averages the temperature difference between the detected scavenging port temperature and the scavenging tube temperature and averages the detected engine load, and then performs the above-described reference value. At the stage when the detected engine load is settled, it is determined whether or not the above-mentioned temperature difference that has been averaged exceeds the reference value by the above-mentioned correspondence. It is good to be abnormal when it exceeds. This method can be performed, for example, by the procedure shown in FIG.
According to this method, preferable abnormality detection can be performed even when the scavenging port temperature, the scavenging pipe temperature, and further the operating load of the engine change over time. That is, for engine operation, the output is increased sequentially from startup, and the output may change depending on the operation state even during steady operation. The temperature difference between the detected scavenging port temperature and the scavenging pipe temperature and the detected engine load are each averaged, and the engine load determines the timing for determining whether the temperature difference exceeds the reference value. By setting the settling time, it is possible to prevent an instantaneous or continuous change from being erroneously determined as abnormal.

The abnormality detection method for a marine diesel engine according to the present invention detects a scavenging port temperature that is a gas temperature in the vicinity of the scavenging port in the scavenging chamber in order to detect a sliding abnormality between the cylinder and the piston. The scavenging tube temperature, which is the gas temperature, is detected, and the average value is obtained by averaging the temperature difference between the scavenging port temperature and the scavenging tube temperature. It is characterized by being abnormal when it is rising.
In addition to this,
・ The scavenging port temperature detector that detects the scavenging port temperature above has a temperature sensing part located just outside the scavenging port where hot gas leaks when blow-by occurs.
The scavenging port temperature detector is attached to a hole provided in the wall of the scavenging chamber by being inserted from the outside of the wall and fixed outside the wall;
・ The engine load is detected together with the scavenging port temperature and scavenging pipe temperature, and the abnormality is determined in consideration of the detected engine load.
It is also preferable that the engine load is replaced with the supercharger speed detected by the supercharger speed detector.

According to the abnormality detection device related to the invention, not only scuffing but also a blow-by phenomenon occurring in the previous stage can be detected, and abnormal wear of the cylinder liner and the piston ring can be detected at an early stage. The processing cost for attaching the detector can be reduced, and it is also preferable from the viewpoint of ensuring the durability of the temperature detector.
In the other abnormality detection device relating to the invention, the installation of the temperature detector is particularly easy and inexpensive, and the attachment and removal of the temperature detector for maintenance or the like is also easy.
By employing another abnormality detection device relating to the invention, it is possible to make an abnormality determination that does not depend on human subjectivity, and human error can be prevented.

By adopting another abnormality detection device relating to the invention, it becomes possible to incorporate an abnormality determination condition according to a change in the outside air state, and the accuracy of abnormality determination is improved.
In other detection devices related to the invention, various engine load conditions during operation are taken into the determination determination, and the accuracy of the abnormality determination is further improved.

  In the diesel engine relating to the invention, it is possible to make a preferable abnormality determination using the above-described abnormality detection device, and it is possible to reduce the cost required for mounting the temperature detector. When an abnormality is detected by the abnormality detection device, appropriate measures can be taken, such as adjusting the amount of lubrication toward the inner wall of the cylinder or the piston ring, or checking the cylinder before the abnormality proceeds. .

According to the abnormality detection method relating to the invention, it is possible to detect abnormal wear of the cylinder liner etc. at an early stage from the blow-by stage, and it is easy to attach the temperature detection means, and the durability of the means can be improved. is there. It is also possible to detect the abnormality with higher accuracy by correcting the influence of the outside air temperature.
According to another abnormality detection method related to the invention, it is possible to perform abnormality detection with higher accuracy by eliminating the influence of a temperature change caused by the engine load.
If other detection methods relating to the invention are employed, it is possible to improve the accuracy of detecting the abnormality of the diesel engine, in particular, by eliminating errors due to instantaneous and temporal changes.

The form about embodiment of invention is shown, The diesel engine 1 shown with sectional drawing, the scavenging port temperature detector 10 installed in the scavenging port 7 vicinity, etc. are shown. It is a conceptual diagram of the abnormality detection apparatus incorporating the scavenging port temperature detector 10. It is a conceptual diagram of the abnormality detection apparatus which further incorporated the scavenging tube temperature detector 12. Furthermore, it is a conceptual diagram of the abnormality detection apparatus which incorporated engine load into abnormality determination. It is a functional block diagram which shows the logic example of abnormality determination.

The first embodiment is introduced in FIGS.
FIG. 1 shows a two-cycle marine diesel engine 1. At the upper part of the engine 1 is a cylinder 2 and a piston 3 that moves in the cylinder 2. The fuel injected into the cylinder 2 and the sucked air are mixed and explode, and the piston 3 is pushed down. The movement of the piston 3 moves the crank 5 via the connecting rod 4 and gives a rotational motion to the main shaft 6. The rotational movement of the main shaft 6 becomes the output of the diesel engine 1. A plurality of cylinders 2 are arranged in the length direction of the main shaft 6, and a piston 3 and a connecting rod 4 are provided for each.

  A scavenging port 7 for taking in combustion air is provided at the bottom of each cylinder 2. There is a scavenging chamber 8 for each cylinder 2 around the scavenging port 7. Each scavenging chamber 8 is connected by a scavenging tube 9 that communicates with the outside air.

In the example of FIGS. 1 and 2, a temperature detector (scavenging port temperature detector) 10 is installed in the vicinity of the scavenging port 7.
If sliding abnormalities occur in the sliding part between the cylinder 2 and the piston 3 due to poor maintenance or lack of lubricating oil, friction on the sliding surface increases, blow-by phenomenon occurs and scuffing tends to occur thereafter. is there. When blow-by occurs, high-temperature exhaust gas leaks under the piston 3 and flows out to the scavenging port 7, and the temperature in the vicinity rises. In this case, the scavenging port temperature detector 10 directly detects the temperature of the high-temperature combustion gas leaked by blow-by, thereby detecting a sliding abnormality at an early stage.

The scavenging port temperature detector 10 is attached by being inserted from the outside into a hole formed so as to penetrate the outer wall 11 of the scavenging chamber 8. The detector 10 is fixed from the outside of the scavenging chamber 8 by fitting the screw portion of the detector 10 to the screw portion provided in the hole of the outer wall 1. The temperature sensing part at the tip of the detector 10 is positioned just outside the scavenging chamber 8 facing the scavenging port 7 so that the temperature of the gas leaking from the scavenging port 7 (scavenging port temperature) can be measured. . Since the outer wall 11 of the scavenging chamber 8 is made of general cast iron, the above hole can be easily processed.
If there is a cover for inspection purposes or the like near the outside of the scavenging port 7, a hole for mounting the temperature detector 10 can be processed into the cover. If such a lid can be processed, it becomes easier to attach the temperature detector 10 and maintain it.
The scavenging port temperature detector 10 uses a resistance temperature detector, but can be similarly implemented using a thermocouple.

  In this case, the output of the scavenging port temperature detector 10 is sent to a determination device so that the determination device determines the occurrence of a sliding abnormality in the diesel engine 1. The determination device (not shown) is connected to the tip of the signal line 13 shown in FIG. 2, and when the output of the temperature detector 10 (temperature near the scavenging port 7) deviates from the normal state, an abnormality is determined and an alarm is issued. Like to do.

  Next, FIG. 3 shows a second embodiment. In this example, in addition to the scavenging port temperature detector 10 being attached as in the examples of FIGS. 1 and 2, a temperature detector (scavenging tube temperature detector) 12 is also installed in the scavenging tube 9. That is, drilling is performed on the outer wall of the scavenging tube 9, the temperature detector 12 is inserted and fixed from the outside of the outer wall, and the temperature sensing part at the tip is inserted into the scavenging tube 9, and the internal gas temperature (scavenging tube). Temperature).

  In the normal operation state without any abnormality, the output of the scavenging port temperature detector 10 and the scavenging tube temperature detector 12 is slightly different, but a sliding abnormality occurs between the cylinder 2 and the piston 3 and the combustion gas blows by. When this happens, only the scavenging port temperature, which is the output of the scavenging port temperature detector 10, rises, and a difference occurs with the output of the scavenging tube temperature detector 12 to deviate from the normal state. The example of FIG. 3 detects an abnormality based on the difference between the outputs (that is, the temperature difference). The determination of abnormality is made to be performed by a determination device (temperature abnormality determination device) 14, and the output of the scavenging port temperature detector 10 and the output of the scavenging tube temperature detector 12 are transmitted to the determination device 14 through signal lines 13 and 15. .

4 and 5 show a third embodiment. In this example as well, the scavenging port temperature detector 10 and the scavenging tube temperature detector 12 are attached as in the example of FIG. 3, and their outputs are sent to the determination device (temperature abnormality determination device) 14 to determine abnormality. Yes. However, in this example, the accuracy of abnormality detection is further increased by putting a reference value corresponding to the load of the diesel engine 1 in the determination condition as described below.
The combustion gas temperature of the diesel engine 1 changes according to the load, for example, the temperature increases as the engine load increases. Therefore, the difference between the output of the scavenging port temperature detector 10 and the output of the scavenging tube temperature detector 12 is abnormal depending on whether or not it deviates more than a certain value compared to a reference value that is normal according to the engine load. Determine. In this example, a turbocharger speed detector is used as the engine load detector 16 and the engine load is substituted by the supercharger speed. However, the governor rack position signal, the output of the dynamometer, or the engine It is also possible to substitute with the number of rotations.

FIG. 5 shows an abnormality determination logic example (functional block diagram) performed by the determination unit 14 in the example of FIG.
In the marine diesel engine 1, there are temporal variations in various data including a load state at the time of start-up and operation. Therefore, in order not to erroneously determine instantaneous data fluctuations as abnormal, the detected output values are averaged to be input values, and abnormalities can be determined by excluding instantaneous or short-term temporal change events. To do.

For this purpose, first, the difference (T ₁ −T ₂ ) between the temperature T ₁ that is the output of the scavenging port temperature detector 10 and the temperature T ₂ that is the output of the scavenging tube temperature detector 12 is taken, and this is taken as the PBP temperature T _3. And Cylinder 2 and the piston 3 between the sliding abnormality occurs in that the blow-by gas coming out leaks, PBP temperature T ₃ becomes abnormally large. However, in order to eliminate erroneous determinations from instantaneous movements, an averaging process S ₁ is performed to take a time average for the temperature T ₃ .
On the other hand, since the combustion temperature of the gas in the cylinder 2 changes according to the load, an abnormality determination line (determination value function; lower part of FIG. 5) indicating the reference value of the PBP temperature according to the load (for example, the supercharger rotation speed) Is determined and stored in the determiner 14.
With continuously measured by the engine load detector 16 of FIG. 4 the rotational speed L for example supercharger performs settling judgment S ₂ For operation of the diesel engine 1, the determination by the change in PBP temperature T ₃ at the time the operation has settled To start. Settling judgment S _2, for example supercharger speed L is determined to settle with a case older than 30 minutes fluctuations within 2% ±.
For even supercharger rotational speed L corresponding to an engine load, a perform averaging processing S ₃ in order to eliminate the instantaneous motional changes, an average supercharger rotational speed obtained by it, the determination unit 14 of the abnormality performs change determination S ₄ by applying the decision line. As a result, if the above measured by the averaging process S ₁ to have been abnormal determination line PBP temperature T _3, it determines that the sliding abnormality occurs, an alarm S ₅ to that effect in a lamp or a buzzer or the like .
Such an abnormality determination logic can be easily realized by combining with a microcomputer, a PLC (programmable logic controller) or the like.
When an abnormality is determined and an alarm is issued, the operator can increase the amount of oil supply or reduce the load according to the state.

As a simplest method, the detection of the sliding abnormality can be performed only by the degree of increase in the output of the scavenging port temperature detector 10. In that case, it is good to make a determination device detect a rise, and to determine abnormality, but a person (operator) can also judge temperature visually.
The determination may be made using only the above-described PBP temperature without considering the engine load. For example, when a situation is detected in which the average value of the PBP temperature has increased abnormally (for example, + 4 ° C.) compared to 30 minutes ago, it is determined that a sliding abnormality has occurred.

DESCRIPTION OF SYMBOLS 1 Diesel engine 2 Cylinder 7 Scavenging port 8 Scavenging chamber 9 Scavenging tube 10 Scavenging port temperature detector 11 Scavenging chamber outer wall 12 Scavenging tube temperature detector 14 Judgment device (temperature abnormality judging device)
16 Engine load detector

Claims (5)

In order to detect sliding abnormalities between the cylinder and the piston, the scavenging port temperature, which is the gas temperature in the vicinity of the scavenging port in the scavenging chamber, and the scavenging tube temperature, which is the gas temperature in the scavenging tube, are detected.
The average value is obtained by averaging the temperature difference between the scavenging port temperature and the scavenging tube temperature, and if it is higher than the standard compared to the average value obtained in the same way before that, it is regarded as abnormal. An abnormality detection method for marine diesel engines.   2. The scavenging port temperature detector for detecting the scavenging port temperature is characterized in that a temperature sensing part is positioned just outside the scavenging port through which high-temperature gas leaks when blow-by occurs. An abnormality detection method for marine diesel engines described in 1.   The scavenging port temperature detector is attached to a hole provided in a wall of the scavenging chamber by being inserted from the outside of the wall and fixed outside the wall. 2. An abnormality detection method for marine diesel engines described in 2.   The marine diesel engine according to any one of claims 1 to 3, wherein an engine load is detected together with a scavenging port temperature and a scavenging pipe temperature, and an abnormality is determined in consideration of the detected engine load. Anomaly detection method.   5. The marine diesel engine abnormality detection method according to claim 4, wherein the engine load is substituted by a supercharger rotational speed detected by a supercharger rotational speed detector.

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