JP6223868B2 - Cylinder oil circulation supply system for 2-cycle diesel engine - Google Patents

Description

  The present invention relates to a circulation supply system and a circulation supply method for supplying cylinder oil into a cylinder of a two-cycle diesel engine.

  In order to suppress wear between parts that make up the engine, prevent engine failure, and reduce the frequency of overhauling the engine and the number of parts that must be replaced when overhauled, the cylinders of a two-cycle diesel engine are lubricated. It is important to supply cylinder oil with excellent properties.

  In a cross-head type two-cycle diesel engine used in ships, etc., system oil for fluid lubrication in a bearing is supplied into a crankcase, and sliding surface lubrication between a cylinder liner and a piston ring is provided in the cylinder. Cylinder oil for is supplied. The cylinder oil is supplied from a supply tank that stores the cylinder oil, and is injected into the cylinder through an oiling nozzle provided in communication with the cylinder liner. The cylinder oil supplied to the inside of the cylinder either burns together with the fuel or is scraped off from the inner wall surface of the cylinder liner to the lantern space installed below by the reciprocating motion of the piston ring.

  Conventionally, cylinder oil used for lubrication in a cylinder contains impurities such as metal wear powder, and therefore has not been reused because it promotes wear of piston rings and cylinder liners. For this reason, new cylinder oil is always supplied into the cylinder, and the cylinder oil scraped down by the piston ring is discharged as drain oil from a waste oil pipe provided in communication with the lantern space. Had been processed.

  In this way, in the conventional cylinder oil supply system, the cylinder oil is disposable after being used only once. Therefore, in a large engine used as power for a ship, the cylinder oil discharged as drain oil is used. The amount was extremely large, which not only led to an increase in cost, but also required consideration for the environment.

  For this reason, development of the cylinder oil circulation supply system which raises the lubrication effect in the cylinder of a 2-cycle diesel engine, can fully demonstrate the performance of an engine, and can eliminate cylinder oil discharged as drain oil is called for.

Japanese Patent Application Laid-Open No. 2011-231685

  The present invention provides a cylinder oil circulation supply system and a circulation supply method capable of enhancing the lubrication effect in a cylinder of a two-cycle diesel engine and eliminating the cylinder oil discharged as drain oil.

  As a result of studies conducted by the present inventors to solve the above-mentioned problems, a mixed cylinder oil obtained by mixing recovered cylinder oil containing fine particles recovered from the cylinder of a two-cycle diesel engine with a new oil at a predetermined ratio By re-supplying the oil into the cylinder, it is possible to effectively increase the lubrication between the parts in the cylinder, and by reusing the recovered cylinder oil, the cylinder oil discharged as drain oil can be eliminated. The present inventors have found that this can be done and have completed the present invention.

That is, the present invention provides circulation and purification tank for storing recovery cylinder oil two-stroke diesel engine which is recovered from the installation lanthanum space below the cylinder liner, the recovery cylinder oil in cleaning tank connected to said cleaning tank And a filter device that is connected to the purification tank and filters the collected cylinder oil in the purification tank through a number of thin papers arranged in parallel. Using a circulating supply system, the recovered cylinder oil adjusted so that the particle size distribution of the contained fine particles has a peak in the range of 0.1 to 0.5 μm is mixed with the new oil. The cylinder oil circulation supply method is characterized in that the mixed cylinder oil prepared so as to be 8 to 12 % by mass is supplied again into the cylinder.

Furthermore, the present invention collects cylinder oil adhering to the exhaust pipe in a purification tank and circulates between the purification tank, a filter device connected to the purification tank, and a centrifuge together with the recovered cylinder oil collected from the lantern space. This is a method of circulating and supplying cylinder oil.

  According to the circulation supply system (or circulation supply method) of the cylinder oil of the present invention, it is possible to effectively increase the lubrication between components in the cylinder and to stably operate the two-cycle diesel engine for a long period of time. . In addition, since the frequency of engine overhaul and parts replacement can be reduced, the time and cost required for maintenance can be greatly reduced.

  By reusing the recovered cylinder oil, the cylinder oil discharged as drain oil can be eliminated. For this reason, it is possible to reduce the cost without wastefully discharging the cylinder oil, and to reduce the problem of environmental pollution.

The conceptual diagram which shows the cylinder oil circulation supply system of the two-cycle diesel engine of this invention Conceptual diagram showing the structure of a crosshead type two-cycle diesel engine Graph showing the results of the shell four-ball friction test Conceptual diagram of shell four-ball friction test equipment Graph showing the particle size distribution of fine particles in the recovered cylinder oil ((a) When purified by a centrifuge, (b) When purified by combined use of a centrifuge and a filter device) Graph showing the transition of the supply amount of mixed oil (mixed oil of recovered cylinder oil and new oil) supplied into the cylinder during the operation test Graph showing changes in piston ring wear Graph showing changes in the amount of cylinder liner wear State diagram of piston ring (drawing substitute photo) State diagram of cylinder liner (drawing substitute photo)

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  In the present invention, a recovered cylinder oil containing fine particles recovered from the cylinder of a two-cycle diesel engine is mixed with a new oil, and prepared so that the amount of the recovered cylinder oil is 0.1 to 30% by mass. A cylinder oil circulation supply system characterized in that mixed cylinder oil is re-supplied into the cylinder (FIG. 1).

  FIG. 2 shows an example of a marine crosshead type two-cycle diesel engine (2). The piston (3) and the piston ring (4) externally fitted to the piston (3) are reciprocated up and down in the cylinder liner (5). The piston rod (6) extending from the lower end of the piston (3) is rotatably connected to the cross head pin (8) at the upper end of the connecting rod (7), and the lower end of the connecting rod (7). Is rotatably attached to the tip of the eccentric arm portion (9a) of the crankshaft (9). The up and down reciprocating sliding of the piston (3) is converted into a rotational motion of the crankshaft (9) through the piston rod (6), the cross head pin (8), and the connecting rod (7) and outputted.

  The cylinder liner (5) is fixed to the cylinder jacket (10) and installed on the upper part of the crankcase (11). A cylinder cover (13) containing an exhaust valve (12) for exhaust gas exhaust is attached to the upper part of the cylinder liner (5).

  The system oil (19) is used as the lubricating oil supplied to each part in the crankcase (11). The system oil is used repeatedly, unlike the cylinder oil, and is replaced after a predetermined period of use.

  The bottom of the cylinder jacket (10) is slidably sealed by the piston stuffing box (14) and the piston rod (6) is slidable. Is forming. When the piston (3) descends, the air taken into the lantern space (15) from the intake port (16) on the side of the cylinder jacket (10) is sucked into the cylinder liner (5) through the scavenging holes (17), and the piston ( It is compressed and burned with fuel by the rise of 3). The exhaust gas generated by the combustion passes through the exhaust valve (12) and is discharged to the exhaust pipe (28).

  An oiling nozzle (18) is provided in communication with the cylinder liner (5), and cylinder oil for lubricating the cylinder liner (5) and the piston ring (4) is injected. In the present invention, the mixed cylinder oil (20) prepared by mixing the recovered cylinder oil (24) recovered from the lanthanum space (15) and the unused new oil (25) at a predetermined ratio is fed from the supply tank (21). It is supposed to be.

  The cylinder oil supplied from the oil supply nozzle (18) into the cylinder is burned together with the fuel or scraped off into the lantern space (15) by the reciprocating motion of the piston (3).

  Conventionally, the cylinder oil that has been scraped off contains a large amount of metal powder generated by abrasion inside the engine and carbon generated after combustion of the fuel, and is considered difficult to reuse. The cylinder oil that had fallen into the tank was discharged from a drain pipe (22) provided in communication with the lantern space (15), and was incinerated or drained as drain oil. A part of the cylinder oil supplied into the engine passes through the exhaust valve (12) together with the exhaust gas and adheres to the exhaust pipe (23). In the past, it was incinerated. As described above, conventionally, cylinder oil dropped in the lantern space or cylinder oil adhering to the exhaust pipe is incinerated or waste oil treated, and new cylinder oil is always supplied into the cylinder.

  The present invention newly found out that the recovered cylinder oil recovered from the lanthanum space (15) has an excellent lubricating effect, and has developed and completed an effective and practical recovery system for recovered cylinder oil. . The lubricity of the recovered cylinder oil will be described below.

  There is a shell four-ball friction test (ASTM D 2783) as a test method for evaluating the lubricating effect of lubricating oil. In the shell four-ball friction test, lubricating oil is put into a sample container in which three steel balls having a diameter of 1/2 inch are fixed. Then, one rotating sphere is pressed from above so as to contact each of the three fixed spheres (FIG. 4). The rotating sphere is rotated at a predetermined speed while applying a predetermined load, and a load (seizure generation pressure) when the rotating sphere is fused (seized) is obtained. Therefore, the larger the value of the load (seizure generation pressure), the less seizure occurs in the engine, and the better the function as a lubricating oil.

  The cylinder oil to be evaluated is unused cylinder oil (new oil), recovered cylinder oil recovered from the lantern space (recovered oil), and mixed oil (new oil: Recovered oil = 7: 3 or new oil: recovered oil = 9: 1), and the seizure generation pressure was measured for each test oil. The recovered oil was recovered from the lanthanum space and then purified with a centrifuge and a filter device.

  Table 1 shows the numerical value of the seizure generation pressure measured for each test oil. From the numerical values shown in the table, it can be confirmed that the recovered oil recovered from the lanthanum space has a higher pressure at which seizure occurs than the new oil, and is excellent in lubricity. In addition, since the seizure generation pressure of the mixed oil is equal to or higher than that of the new oil, it can be confirmed that the lubricity of the new oil can be improved by mixing the recovered oil with the new oil ( (Figure 3).

  Table 2 shows the physical properties and components of the test oil subjected to the shell four-ball friction test.

  In the table, when comparing the content of new oil and recovered oil, the content of insoluble content of pentane in the new oil is 0.02%, whereas the content of insoluble content in recovered pentane is 1.11%. In the recovered oil, it was confirmed that the content of pentane insoluble matter was increased about 50 times. It can also be confirmed that the amount of insoluble pentane in the mixed oil prepared by mixing the recovered oil with the new oil to a predetermined ratio is increased.

  These results indicate that the recovered oil recovered from the lanthanum space contains a large amount of fine particles shown as insoluble in pentane, and exhibits an excellent effect in preventing seizure. This also shows that the lubricity is improved and seizure can be suppressed by mixing. The ratio of recovered oil to be mixed with the new oil is 0.02% for the insoluble content of pentane and 1.11% for the recovered oil. Even if 0.1% of the recovered oil is added to the new oil, The amount of penta-insoluble matter is increased by 0.001%, and the amount of pentane-insoluble matter contained in the new oil is equivalent to increasing by 5%, so that it can be expected to have a sufficient effect for preventing seizure. . Therefore, the ratio of the recovered oil to be blended with the new oil is preferably 0.1% or more.

  On the other hand, the larger the amount of recovered oil blended with the new oil, the more effective the prevention of seizure can be expected. However, when a two-cycle diesel engine is stably operated continuously as a power engine in a ship, etc. It was confirmed that the upper limit of the amount of oil (recovered oil) was about 30% by mass of the cylinder oil supplied into the cylinder. For this reason, as a circulation system for operating a two-cycle diesel engine for a long period, it is preferable that the ratio of the recovered oil blended with the mixed oil is 30% as an upper limit.

  Thus, the lubricating oil circulation supply system of the present invention mixes the recovered cylinder oil containing fine particles recovered from the cylinder of the two-cycle diesel engine with the new oil, and the recovered cylinder oil is 0.1 to 30 mass. %, The wear of the two-cycle diesel engine is suppressed, and the engine can be stably operated continuously over a long period of time.

  As shown in FIG. 1, the recovered cylinder oil (24) recovered from the lantern space (15) is temporarily stored in the recovery tank (26). The cylinder oil can be collected using an oil drain pipe (22) provided in communication with the lantern space. The recovery tank (26) is a cylinder that is continuously scraped into the lantern space (15) until the purification process of the recovered cylinder oil (24) stored in the purification tank (27) connected thereto is completed. The oil is collected and temporarily stored. After the purification process of the purification tank (27) is completed and the cylinder oil in the purification tank is transferred to the supply tank (21), the collection cylinder in the collection tank (26) The oil is transferred to the purification tank (27). Therefore, it is preferable that the recovery tank (26) has a volume sufficient to recover and store the cylinder oil accumulated in the lantern space (15) while the recovery cylinder oil in the purification tank (27) is purified.

  A part of the cylinder oil supplied into the engine passes through the exhaust valve (12) together with the exhaust gas and adheres to the exhaust pipe (23) (FIG. 2). Cylinder oil adhering to such an exhaust pipe (23) has been conventionally incinerated or waste oil treated, but by collecting it in the recovery tank (26), recovered cylinder oil (24) recovered from the lantern space (15) ) And can be purified and reused (FIG. 1).

  The recovery cylinder oil (24) stored in the recovery tank (26) is transferred to a purification tank (27) connected to the recovery tank (26). The purification tank (27) stores the recovered cylinder oil (24) and circulates the recovered cylinder oil between the centrifuge (28) connected to the purification tank (27) or the filter device (29). Thus, impurities such as metal powder having a large particle diameter and carbon contained in the recovered cylinder oil are removed to purify the cylinder oil.

  The centrifuge (28) and the filter device (29) can be freely connected to the purification tank (27) .For example, the centrifuge (28) and the filter device (29) are arranged in series or in parallel. Although it is possible to connect to the purification tank, as shown in FIG. 1, the centrifuge (28) is connected to the purification tank (27), and the recovered cylinder oil is circulated between the purification tank and the centrifuge. In addition to forming the first circulation circuit (A), a filter device (29) is connected between the purification tank (27) and the centrifuge (28) separately from the first circulation circuit (A). It is preferable to form a second circulation circuit (B) for returning the recovered cylinder oil (24) from the purification tank (27) to the purification tank (27) through the filter device (29) and the centrifugal separator (28). By forming such a circulation circuit, the first purification process of the cylinder oil by the first circulation circuit (A) and the second purification of the cylinder oil by the second circulation circuit (B) according to the situation. Processing can be efficiently performed simultaneously or continuously. In addition, by using a common centrifuge for the first purification process and the second purification process, space can be saved, and the purification system can be easily incorporated in a limited space in the ship. It is possible to operate while purifying while the engine is in operation, such as a ship.

  The centrifuge (28) is intended to remove impurities having a large particle size contained in the recovered cylinder oil (24). The filter device (29) is for the purpose of microfiltration of the recovered cylinder oil. For example, the filter device (29) is mixed into the cylinder oil using a microfiltration device that uses a filter element in which many thin papers are stacked. It is preferable to remove particles such as metal powder generated by engine wear and carbon generated by fuel combustion by attaching them to paper fibers using Brownian motion. Such a microfiltration device is disclosed in Japanese Patent Application Laid-Open No. 11-257038, and includes a filter element in which a large number of thin papers such as tissue papers are laminated. Impurities such as metal powder and carbon contained in are attached to paper fibers and removed by Brownian motion of particles.

  The filter element may have a structure in which long paper is wound in the form of toilet paper, or may be a stack of a large number of papers cut into a disk shape. Filtration with such a microfiltration means is achieved by the impurities mixed in the cylinder oil moving in the oil by Brownian motion and adhering to the paper fibers. Therefore, in order to achieve effective filtration of impurities, it is required that the impurities be in a state that can exhibit a sufficient Brownian motion in oil. If the percentage of impurities is large, the Brownian motion of impurities in the oil decreases, the movement of impurities adhering to the engine inner wall etc. into the oil decreases, and the amount of impurities present in the oil also decreases. However, the amount of paper attached to the fiber is reduced, and the filtration efficiency is lowered.

  Therefore, when the concentration of impurities contained in the recovered cylinder oil (24) in the purification tank (27) is high, first, the first purification process of the recovered cylinder oil by the first circulation circuit (A) is performed. In addition, if the second purification process of the recovered cylinder oil by the second circulation circuit (B) is performed, since the large impurities are removed first by the centrifuge, it is possible to reduce the clogging of the filter. Impurity removal efficiency can be increased.

  On the other hand, when the concentration of impurities contained in the recovered cylinder oil in the purification tank is low, the first purification process by the first circulation circuit (A) and the second purification process by the second circulation circuit (B). Can be performed simultaneously in parallel, and the recovered cylinder oil can be efficiently purified.

  The recovered cylinder oil (24) is mixed with water generated by the combustion of the fuel, and the lubrication performance is degraded. For this reason, it is preferable that the purification tank (27) is heated to about 110 to 120 ° C. and the contained cylinder oil is heated to evaporate the contained water to restore the lubricating performance.

  The particle size distribution of the fine particles contained in the recovered cylinder oil purified in the purification tank (27) is purified using only the centrifuge (28), and the centrifuge (28) and the filter device (29) FIG. 5 shows a case where purification is performed in combination.

  As shown in FIG. 5, both the case of purification using only the centrifuge (28) (a) and the case of purification using the centrifuge (28) and the filter device (29) (b) are collected. The particle size distribution of the fine particles contained in the cylinder oil has a peak in the range of 0.1 to 1 μm. Further, when the two graphs are compared, when the purification is performed using only the centrifuge (28), there is a peak in the range of the particle size of 6 to 60 μm, while the centrifuge (28 ) And the filter device (29) for purification (b), there is no particle of 10 μm or more, and there is a main peak in the particle size range of 0.1 to 1 μm. A sharp peak appears in the range of ˜0.5 μm. If particles with a large particle size of 10 μm or more are mixed, the surface of the engine parts may be damaged to promote wear and the engine may be damaged. As such, it is preferable to use one that has been purified by a filter device.

  The purified recovered cylinder oil (24) and unused cylinder oil (new oil) (25) are mixed by injecting cylinder oil (new oil) (25) into the purification tank (27). The mixed oil (20) prepared in the purification tank (27) is transferred to the supply tank (21), and is lubricated between the cylinder liner (5) and the piston ring (4) for lubrication. ) Is again injected into the engine.

  Although FIG. 1 shows an example in which the recovered cylinder oil (24) and unused cylinder oil (new oil) (25) are mixed in the purification tank (27), they need to be mixed in the purification tank (27). It is also possible to prepare mixed oil in the supply tank (21).

  The recovery cylinder oil is transferred from the recovery tank (26) to the purification tank (27) where the transfer of the recovery cylinder oil (24) to the supply tank (20) is completed, and the recovery process of the recovery cylinder oil is performed again. In this way, the recovery tank (26), the purification tank (27), and the supply tank (21) are connected, and the recovery cylinder oil (24) is sequentially transferred to recover and purify the cylinder oil for each tank. Since the supplying process can be repeated step by step, an efficient purification process can be performed while the engine is running.

  The pump (P) is arranged in the middle of the pipe for transferring the cylinder oil between the tanks. FIG. 1 shows an example of the pump, but the cylinder oil can be transferred smoothly. There is no particular limitation, and the arrangement of the pumps may be adjusted as appropriate depending on the length and thickness of the transfer pipe.

  An effect confirmation test conducted on the cylinder oil circulation supply system (circulation supply method) of the present invention will be described as an example.

"Verification test 1"
The cylinder oil circulation supply system of the present invention is installed in a ship (high-speed cargo ship) equipped with a 2-cycle diesel engine (Mitsubishi Heavy Industries, Ltd. 9UEC52LSE). Carried out. During the navigation test, the amount of new oil and recovered oil that make up the mixed oil supplied to the cylinder was measured.

  FIG. 6 shows a graph showing the transition of the supply amount of the new oil and the recovered oil constituting the mixed oil to be supplied into the cylinder. Here, the vertical axis of the graph shows the numerical value obtained by converting the supply amount of new oil and recovered oil supplied to the engine as the supply amount required per unit work of the engine (consumption rate per unit work). Yes. Specific numerical values on the graph are shown in Table 3.

  In Confirmation Test 1, a mixed cylinder oil (mixed oil) containing about 8-12% of recovered oil was re-supplied into the cylinder (Table 3), and a navigation test for about 10 months (travel time about 4,040) It was possible to effectively suppress the internal wear of the engine in time) and to complete the navigation safely.

"Verification test 2"
By disassembling the engine during or after the navigation test of Confirmation Test 1, measure the surface condition of each component (piston ring, cylinder liner, etc.) or the dimensions of each part, and compare with the condition before the navigation test starts. The degree of engine wear was evaluated.

  FIG. 7 is a graph showing changes in the amount of wear of the piston ring based on the numerical value obtained by measuring the diameter of the piston ring after 1,784 hours of operation. The wear rate of the piston ring in the operational test is 0.024 mm per 1,000 hours. Normally, the wear limit of the piston ring is 3 mm, so it can be considered that navigation is possible for approximately 125,000 hours. This indicates that it is possible to operate continuously without exchanging the piston ring for a long period of 30 years if it is a normal operation, generally in a cycle of 2 to 3 years. The service life of the conventional two-cycle diesel engine, which is supposed to be overhauled, is dramatically improved.

  FIG. 8 is a graph showing changes in the amount of wear of the cylinder liner based on the numerical values obtained by measuring the inner diameter of the cylinder liner after 3,222 hours of operation. The wear rate of the cylinder liner in the operational test is 0.027 mm per 1,000 hours. Usually, the wear limit value of the cylinder liner is 3.5 mm, so it is considered that navigation is possible for about 130,000 hours. This indicates that it is possible to operate continuously without replacing the cylinder liner for a long period of 31 years under normal operation. The period until the overhaul in the 3-year cycle) can be significantly improved.

  FIG. 9 shows the state of the piston ring observed during the operation test. As shown in the figure, there was no change in the surface of the piston ring, and it was confirmed that a good state was maintained during the test period.

  FIG. 10 shows the state of the cylinder liner (replica surface image) after 1,784 hours of operation. The wear of the cylinder liner was evaluated by an image obtained by photographing the surface of the replica obtained from the inner surface of the cylinder liner. As shown in the figure, it was confirmed that there was no significant change in the surface of the cylinder liner, and that it maintained a good state.

DESCRIPTION OF SYMBOLS 1 Cylinder oil circulation supply system 2 2 cycle diesel engine 3 Piston 4 Piston ring 5 Cylinder liner 6 Piston rod 7 Connecting rod 8 Crosshead pin 9 Crankshaft 9a Arm part 10 Cylinder jacket 11 Crankcase 12 Exhaust valve 13 Cylinder cover
14 Piston stuffing box 15 Lantern space 16 Intake port 17 Scavenging hole 18 Lubrication nozzle 19 System oil 20 Mixed cylinder oil (mixed oil)
21 Supply tank 22 Drain oil pipe 23 Exhaust pipe 24 Recovery cylinder oil (recovered oil)
25 Unused cylinder oil (new oil)
26 Recovery tank 27 Purification tank 28 Centrifuge 29 Filter device P Pump A First circulation circuit (first purification process)
B Second circulation circuit (second purification process)

Claims (2)

A purification tank for storing recovery cylinder oil two-stroke diesel engine which is recovered from the installation lanthanum space below the cylinder liner, centrifugation purifying circulating the recovery cylinder oil in cleaning tank connected to said cleaning tank A cylinder oil circulation supply system comprising: a separator; and a filter device that is connected to the purification tank and filters the collected cylinder oil in the purification tank through a plurality of thin papers arranged in parallel. The recovered cylinder oil adjusted so that the particle size distribution of the contained fine particles has a peak in the range of 0.1 to 0.5 μm is mixed with the new oil, and the blended amount of the recovered cylinder oil is 8 to 12 % by mass. A cylinder oil circulation supply method, wherein the mixed cylinder oil prepared so as to be re-supplied into the cylinder. Cylinder oil adhering to the exhaust pipe is collected in a purification tank, and is circulated between the purification tank, a filter device connected to the purification tank, and a centrifuge together with the recovered cylinder oil collected from the lantern space. circulating supply method of a cylinder oil according to claim 1 Symbol placement.