JP2009270545A - In-oil diluted fuel separating device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in-oil diluted fuel separating device of an internal combustion engine which can efficiently separate fuel contained in lubricating oil of an internal combustion engine while suppressing the deterioration of the oil. <P>SOLUTION: The device 20 is equipped with an oil storage part (an oil pan 18) which stores lubricating oil of an internal combustion engine and includes a first chamber 21 and second chamber 22 demarcated from the first chamber so as to introduce the lubricating oil in the first chamber, and an air-bubble generating mechanism 26 which generates air-bubbles in the lubricating oil in the first chamber. An oil passage 19 having an oil pump 36 for supplying the lubricating oil in the second chamber to a lubricated part in the internal combustion engine is connected to the inside of the second chamber. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an oil-in-oil diluted fuel separation device for an internal combustion engine, and more particularly, to an oil dilution in an internal combustion engine capable of efficiently separating fuel contained in lubricating oil of the internal combustion engine while suppressing deterioration of the oil. The present invention relates to a fuel separator.

2. Description of the Related Art Conventionally, an oil-in-oil diluted fuel separator for an internal combustion engine is known that evaporates and separates fuel contained in oil by heating the lubricating oil in order to suppress dilution due to fuel contamination of the lubricating oil (for example, Patent Document 1).
Patent Document 1 discloses that an oil heater is provided in the middle of an oil circuit of an internal combustion engine, and the lubricating oil flowing in the oil circuit is heated by this heater to vaporize and separate the fuel.
Further, Patent Document 2 discloses that a heater is provided at the bottom of the oil pan, and the lubricating oil in the oil pan is heated by this heater to vaporize and separate the fuel.

JP 2004-190513 A JP 2004-340056 A

  However, in Patent Document 1, a relatively large amount of lubricating oil that passes through an oil passage that connects the oil pan and the lubricated portion of the engine or a bypass passage provided in the oil passage is heated by a heater. There are problems such as large energy loss and heat deterioration of the oil. Moreover, in the said patent document 2, since all the oil in an oil pan is heated, the above-mentioned problem becomes very remarkable.

  The present invention has been made in view of the above situation, and provides a diluted fuel separation apparatus for an internal combustion engine that can efficiently separate the fuel contained in the lubricating oil of the internal combustion engine while suppressing deterioration of the oil. The purpose is to provide.

The present invention is as follows.
1. An oil storage section that stores lubricating oil of an internal combustion engine and has a first chamber and a second chamber partitioned from the first chamber so that the lubricating oil in the first chamber can be introduced;
A bubble generating mechanism for generating bubbles in the lubricating oil in the first chamber,
An oil passage having an oil pump for supplying lubricating oil in the second chamber to a lubricated part of the internal combustion engine is disposed in the second chamber. Fuel separator.
2. The oil storage volume of the first chamber is smaller than the oil storage volume of the second chamber. The oil-diluted fuel separator for an internal combustion engine as described.
3. In the main body of the internal combustion engine, there is provided an oil guide portion that guides the lubricating oil that has lubricated the piston that is the lubricated portion to the first chamber. Or 2. 2. An oil-in-diluted fuel separator for an internal combustion engine according to 1.
4). The said 1st chamber is arrange | positioned directly under the piston which is the said to-be-lubricated part. Or 2. 2. An oil-in-diluted fuel separator for an internal combustion engine according to 1.
5. The second chamber is disposed immediately below the passage for returning the lubricating oil lubricated around the head as the lubricated portion to the oil storage portion. To 4. An oil-in-oil diluted fuel separator for an internal combustion engine according to any one of the above.

According to the fuel-in-oil diluted fuel separator for an internal combustion engine of the present invention, bubbles are generated in the lubricating oil in the first chamber of the oil reservoir by the bubble generating mechanism, and the fuel contained in the lubricating oil is vaporized by the bubbles. Promoted. Then, the lubricating oil from which the fuel is vaporized and separated in the first chamber is guided to the second chamber and supplied to the lubricated portion via the oil passage by the oil pump. As described above, since the bubble generation mechanism is provided and the vaporization of the fuel in the lubricating oil in the first chamber of the oil reservoir is promoted by the bubbles, the lubricating oil is heated to vaporize and separate the fuel as in the prior art. Compared to those, the fuel contained in the lubricating oil can be efficiently separated while suppressing the deterioration of the oil. In addition, since the oil storage part is provided with the first chamber and the second chamber partitioned from the first chamber so that the lubricating oil in the first chamber can be introduced into the second chamber, the lubricating oil in the first chamber is sufficiently supplied. It is possible to guide into the second chamber in a state of being defoamed. As a result, it is difficult for the oil pump to suck the lubricating oil mixed with air bubbles, and a reduction in the discharge capacity of the oil pump can be suppressed.
In addition, when the oil storage volume of the first chamber is smaller than the oil storage volume of the second chamber, the fuel can be separated more efficiently for a relatively small amount of lubricating oil in the first chamber, and in the second chamber A relatively large amount of lubricating oil can be secured and supplied to the lubricated part.
Further, in the case where an oil guide portion for guiding the lubricating oil that has lubricated the piston, which is the lubricated portion, to the first chamber is provided in the main body of the internal combustion engine, the lubricating oil containing a relatively large amount of fuel is provided. Since it is guided into the first chamber by the oil guide section, the separation efficiency of the fuel in the lubricating oil in the first chamber can be further improved.
Further, when the first chamber is arranged directly below the piston that is the lubricated part, the lubricating oil containing a relatively large amount of fuel falls directly into the first chamber, The separation efficiency of the fuel in the lubricating oil can be further improved.
Further, when the second chamber is arranged immediately below the passage for returning the lubricating oil lubricated around the head, which is the lubricated part, to the oil storage part, mixing of the fuel lubricated around the head is relatively difficult. Since a small amount of lubricating oil can be returned directly to the second chamber, it is easy to secure the lubricating oil in the second chamber.

1. Embodiment 1 An oil-diluted fuel separator for an internal combustion engine. The oil-diluted fuel separator for an internal combustion engine according to the present invention includes an oil reservoir and a bubble generation mechanism described below.

As long as the “oil storage section” has a second chamber that is partitioned from the first chamber so as to store the lubricating oil of the internal combustion engine and introduce the lubricating oil in the first chamber and the first chamber, The structure, shape, material, etc. are not particularly limited.
Examples of the oil reservoir include an oil pan provided in the lower part of the main body of the internal combustion engine, an oil tank provided separately from the main body of the internal combustion engine, and the like.

As a partition form of the first chamber and the second chamber, for example, (1) a form in which the first chamber and the second chamber are partitioned in a horizontal direction by a partition wall raised from the bottom wall of the oil reservoir ( 1), (2) an oil container is provided in the upper part of the oil reservoir, the internal region of the oil container is a first chamber, the lower internal region of the oil reservoir is a second chamber, The form (refer FIG. 2) etc. which the 2nd chamber is divided in the up-down direction can be mentioned.
According to the configuration (1), the height of the oil reservoir can be made compact, and the lubricating oil in the first chamber can be smoothly introduced into the second chamber. Moreover, according to the said (2) form, while the dimension of the horizontal direction of an oil storage part can be made compact, the lubricating oil of the state from which the bubble was fully degas | defoamed can be introduce | transduced into a 2nd chamber.

  In the form (1), for example, the lubricating oil in the first chamber can be introduced into the second chamber through a communication path formed at the upper end of the partition wall. Thereby, the lubricating oil in a state where the bubbles are sufficiently degassed can be smoothly introduced into the second chamber. Examples of the communication path include an upper end edge of the partition wall and a communication hole.

  For example, substantially all of the lubricating oil that lubricates the lubricated portion of the internal combustion engine and returns to the oil storage portion may be introduced into the first chamber, but a predetermined portion (for example, the lubricated portion of the internal combustion engine (for example, It is preferable to introduce a part of the lubricating oil that lubricates the piston and the like and returns to the oil reservoir. This is because the separation efficiency of the fuel in the lubricating oil can be improved.

An oil passage having an oil pump for supplying lubricating oil in the second chamber to a lubricated portion of the internal combustion engine is disposed in the second chamber.
When the oil reservoir is an oil pan, an oil strainer is usually provided at one end of the oil passage, and this oil strainer is disposed (connected) in the oil pan.
Examples of the oil passage include one or a combination of two or more of piping, a passage formed in a main body or a mechanism portion of an internal combustion engine, a space, and the like.
Examples of the oil pump include a trochoid type, an internal gear type, an external gear type, and an inner gear type. This oil pump can be operated, for example, by a driving force of an internal combustion engine, or can be operated by a drive source different from the internal combustion engine.

Here, for example, the oil storage volume of the first chamber can be smaller than the oil storage volume of the second chamber. The ratio (C1 / C2) between the oil storage volume C1 of the first chamber and the oil storage volume C2 of the second chamber is preferably 0.2 to 0.5 (particularly 0.25 to 0.3). This is because the fuel separation efficiency in the first chamber can be further increased and a large amount of lubricating oil can be secured in the second chamber.
In the above-described form (1), for example, the bottom wall of the oil reservoir is formed in a stepped shape, and the bottom wall constituting the first chamber is set at a higher level than the bottom wall constituting the second chamber. The storage volume can be made smaller than the oil storage volume of the second chamber. Thereby, the dimension of the height direction of an oil storage part can be made more compact.

  As long as the “bubble generating mechanism” generates bubbles in the lubricating oil in the first chamber, the structure, bubble generation mode, timing, etc. are not particularly limited. Here, the fuel contained in the lubricating oil is prevented from evaporating due to the viscosity resistance of the lubricating oil. However, by generating bubbles in the lubricating oil by the bubble generating mechanism, the fuel is wrapped in the bubbles. And / or pushed up to promote vaporization of the fuel contained in the lubricating oil.

  As the bubble generating mechanism, for example, (1) a plurality of bubble holes are formed in the bottom wall and / or the side wall constituting the first chamber of the oil reservoir, and one end side of each of the bubble holes has a compressor or the like. A configuration in which the other end of the air passage connected to the air source is connected (see FIGS. 1 and 2). (2) One end of the oil passage is connected to an air source such as a compressor. A configuration (see FIG. 3) in which a bubble tube connected to the other end of the air passage and formed with a plurality of bubble nozzles is arranged.

  In the modes (1) and (2), for example, a control valve for opening and closing the air passage is provided in the middle of the air passage, and the control valve is opened and closed by the control unit based on the rotational speed, hydraulic pressure, oil temperature, etc. of the internal combustion engine. You may make it control. As a result, the fuel can be intensively separated when the fuel dilution in the lubricating oil of the internal combustion engine is relatively large.

  The diameter of the bubbles generated by the bubble generation mechanism can be, for example, 0.1 to 5 mm (preferably 1 to 2 mm). Thereby, the fuel contained in lubricating oil can be more efficiently separated.

  Examples of the “lubricated part of the internal combustion engine” include a crankshaft, a connecting rod, a piston, a camshaft, and a drive system. Of these, relatively large amount of fuel leaking from the gaps in the cylinder inner wall surface of the piston is mixed in the lubricating oil that circulates around the piston such as the crankshaft, the connecting rod, and the piston and is returned to the oil reservoir. . On the other hand, almost no fuel is mixed in the lubricating oil that circulates around the head such as the camshaft and the drive system and is returned to the oil reservoir. Further, the lubricating oil circulating around the piston is usually returned to the oil reservoir through a gap between the piston and the cylinder. On the other hand, the lubricating oil that circulates around the head is usually returned to the oil reservoir through a communication path that is formed in the cylinder block and cylinder head of the engine and connects the crank chamber and the space in the head cover. Or returned to the oil reservoir through the case or belt case.

Embodiment 1 For example, the oil-diluted fuel separator for an internal combustion engine according to the present invention includes (1) an oil guide portion that guides the lubricating oil that lubricates the piston, which is the lubricated portion, to the first chamber in the main body of the internal combustion engine. Form (see FIGS. 1 and 4) provided, (2) Form (see FIG. 2) in which the first chamber is disposed immediately below the piston as the lubricated portion, (3) The second chamber However, a configuration (see FIGS. 1 and 4) in which the lubricating oil that has lubricated around the head, which is the lubricated portion, is disposed directly below the passage that returns the oil to the oil storage portion. Among these, it is preferable that they are a combination of the above forms (1) and (3) and a combination of the above forms (2) and (3). This is because the fuel separation efficiency in the first chamber can be further improved and the lubricating oil in the second chamber can be easily secured.
In the above (1) mode, examples of the main body of the internal combustion engine include an oil reservoir and a crankcase.

  In the embodiments (1) and (2), for example, (a) the main body of the internal combustion engine is formed in a cylinder block and a cylinder head of the engine and passes through a communication path that connects the crank chamber and the space in the head cover. Another oil guide for guiding the lubricating oil returned to the oil reservoir to the second chamber is provided, or (b) in the oil reservoir through the chain case or the belt case of the engine in the main body of the internal combustion engine. Another oil guide part for guiding the lubricating oil returned to the second chamber to the second chamber may be provided. Accordingly, the lubricating oil in which almost no fuel is mixed can be guided and introduced into the second chamber by the other oil guide portion, and the separation efficiency of the fuel in the lubricating oil in the first chamber can be further improved. From the viewpoint of further improving the separation efficiency, a combination of the above forms (a) and (b) is preferable.

  As the form (3), for example, (a) the second chamber is formed in the cylinder block and the cylinder head of the engine and is disposed immediately below a communication path that connects the crank chamber and the space in the head cover. Form (refer to FIG. 1), (b) The second chamber may be disposed directly below the chain case or belt case of the engine (refer to FIG. 4). From the standpoint that lubricating oil can be more easily secured, a combination of the above-described forms (a) and (b) is preferable.

  In a cylinder injection type internal combustion engine, in addition to main injection for injecting fuel into the cylinder in the vicinity of compression top dead center, sub-injection for injecting fuel into the cylinder before and after the main injection (for example, pilot injection, When performing post injection or the like, the injected fuel is likely to adhere to the inner wall surface of the cylinder, and the attached fuel is likely to be mixed into the lubricating oil. Therefore, the first embodiment. The oil-diluted fuel separator for an internal combustion engine according to the above can be suitably used as an oil-diluted fuel separator for an in-cylinder injection type internal combustion engine that performs sub-injection before and after main injection.

Hereinafter, the present invention will be described in detail with reference to the first and second embodiments with reference to the drawings.
In this embodiment, as an “internal combustion engine” according to the present invention, an in-cylinder injection type engine that performs sub-injection before and after main injection is illustrated.

Example 1
(1) Engine Configuration As shown in FIG. 1, the engine 1 according to the first embodiment includes a cylinder block 1a in which a cylinder 2 is formed, and a cylinder head 1b fixed to the upper portion of the cylinder block 1a. ing. A piston 3 is supported in the cylinder 2 of the cylinder block 1a so as to be able to reciprocate. In addition, a crankcase 1c configured to rotatably support the crankshaft 4 is fixed to the lower portion of the cylinder block 1a. The crankshaft 4 is connected to the piston 3 via a connecting rod 5. A combustion chamber 6 surrounded by the top surface of the piston 3, the wall surface of the cylinder head 1b, and the wall surface of the cylinder 2 is formed above the piston 3.

  The cylinder head 1b has an intake port 8a having one end connected to the intake pipe 7a and the other end connected to the combustion chamber 6, and one end connected to the exhaust pipe 7b and the other end connected to the combustion chamber 6. The exhaust port 8b is formed. The cylinder head 1b is provided with an intake valve 9a for opening and closing the intake port 8a and an exhaust valve 9b for opening and closing the exhaust port 8b, and camshafts 10a and 10b for driving the intake valve 9a and the exhaust valve 9b, respectively. It is supported rotatably. Further, a cylinder head cover 1d that covers the valve mechanism is attached to the upper portion of the cylinder head 1b. One end side of the intake pipe 7 a is connected to the air cleaner box 11. In the middle of the intake pipe 7a, a throttle valve 12 for adjusting the amount of intake air flowing through the intake pipe 7a is provided.

  The space 13 in the cylinder head cover 1d is connected through the PCV valve 15a to the other end of the first return path 15 whose one end is connected to the downstream side of the throttle valve 12 of the intake pipe 7a. Further, the space 13 in the cylinder head cover 1d is connected to the other end side of the second return path 16 whose one end side is connected to the upstream side of the throttle valve 12 of the intake pipe 7a.

  An oil pan 18 (illustrated as an “oil storage section” according to the present invention) for storing lubricating oil is attached to the lower portion of the crankcase 1c. The oil pan 18 and the lubricated part of the engine 1 are connected via an oil circulation path (not shown) including an oil passage 19.

(2) Configuration of the oil-diluted fuel separator The oil-diluted fuel separator 20 according to the first embodiment includes the oil pan 18 having the first chamber 21 and the second chamber 22, as shown in FIG. ing. The first chamber 21 and the second chamber 22 are partitioned adjacent to each other in the horizontal direction by a partition wall 24 raised from the bottom wall 23 of the oil pan 18. Further, the bottom wall 23 of the oil pan 18 is formed in a stepped shape, and the bottom wall 23 a constituting the first chamber 21 is at a higher level than the bottom wall 23 b constituting the second chamber 22. The oil storage volume C1 of the first chamber 21 is set to about 1.2 liters, and the oil storage volume C2 of the second chamber 22 is set to about 4 liters. Therefore, the ratio (C1 / C2) between the oil storage volume C1 of the first chamber 21 and the oil storage volume C2 of the second chamber 22 is set to 0.3.

  A bubble generating mechanism 26 that generates bubbles in the lubricating oil in the first chamber 21 is connected to the first chamber 21. The bubble generating mechanism 26 includes a plurality of bubble holes 27 formed in the bottom wall 23 a of the first chamber 21. The plurality of bubble holes 27 have a diameter of about 1 mm and are formed at equal pitch intervals over the entire area of the bottom wall 23a. Further, below the bottom wall 23 a of the oil pan 18, a lower wall 29 that forms an air space 28 connected to each bubble hole 27 is provided. The air space 28 is connected to the other end of an air pipe 31 whose one end is connected to the compressor 30. In the middle of the air pipe 31, there is provided an electromagnetic valve 33 that is electrically connected to a control unit 32 comprising a CPU, RAM, ROM and the like. The control unit 32 opens the electromagnetic valve 33 to open the air pipe 31 when the engine is started, and closes the air pipe 31 by closing the electromagnetic valve 33 when the engine is stopped.

  An oil strainer 35 provided on one end side of the oil passage 19 is disposed in the second chamber 22. An oil pump 36 for supplying the lubricating oil in the second chamber 22 to the lubricated part of the engine 1 is provided in the middle of the oil passage 19. The second chamber 22 is formed in the cylinder block 1a and the cylinder head 1b of the engine 1 and is disposed immediately below a communication path 37 that connects the crank chamber 14 and the space 13 in the cylinder head cover 1d.

  A plate-like oil guide portion 38 that guides the lubricating oil returned to the oil pan 18 through the gap between the piston 3 and the cylinder 2 to the first chamber 21 at the lower portion of the crankcase 1 c and the upper portion of the oil pan 18. Is provided.

(3) Operation of the oil-in-diluted fuel separation device Next, the operation of the oil-in-diluted fuel separation device 20 having the above configuration will be described.
In the present embodiment, the cylinder injection engine 1 that performs the sub-injection before and after the main injection is employed, so that the fuel adhering to the inner peripheral surface of the cylinder is mixed with the lubricating oil and the gap between the piston 3 and the cylinder 2 The fuel dilution rate in the lubricating oil that passes through and returns to the oil pan 18 increases.

  During engine operation, lubricating oil that circulates around the pistons such as the crankshaft 4, the connecting rod 5, and the piston 3 as a lubricated part of the engine passes through the gap between the piston 3 and the cylinder 2 and passes to the oil guide part 38. It is guided and returned into the first chamber 21 of the oil pan 18. On the other hand, lubricating oil that circulates around the heads of the camshafts 10a and 10b, the drive system, etc., as a lubricated part of the engine is returned to the second chamber 22 of the oil pan 18 through the communication path 37, or Are returned to the second chamber 22 of the oil pan 18 through a chain case or belt case (not shown).

During engine operation, compressed air from the compressor 30 is sent to the bubble hole 27 through the open air pipe 31 and the air space 28, and a large number of bubbles are contained in the lubricating oil in the first chamber 21. Has been generated. The fuel contained in the lubricating oil in the first chamber 21 is encapsulated or pushed up by the generated bubbles, and vaporization is promoted against the viscosity resistance of the lubricating oil. The vaporized fuel is mixed with air naturally degassed from the lubricating oil and blow-by gas, and is sent from the crank chamber 14 to the space 13 in the cylinder head cover 1d through the communication path 37. The blow-by gas is recirculated to the intake pipe 7a through the first return path 15 in a low-load operation state of the engine 1 (an operation state in which the throttle valve is open), and the engine 1 is in a high-load operation state (throttle valve operation). In an operation state where the opening degree is large), the refrigerant is recirculated to the intake pipe 7 a via the second recirculation path 16 in addition to the first recirculation path 15.
When the engine 1 is in a low load operation state, fresh air flowing upstream of the throttle valve 12 of the intake pipe 7a via the second return path 16 is sucked into the space 13 in the cylinder head cover 1d and blow-by in the space 13 is blown. Gas will be ventilated.

  On the other hand, the lubricating oil from which the fuel is vaporized and separated in the first chamber 21 gets over the upper edge of the partition wall 24 and is introduced into the second chamber 22. Then, the lubricating oil in the second chamber 22 is pumped to the lubricated part of the engine 1 through the oil passage 19 via the oil strainer 35 by the operation of the oil pump 36.

(4) Effects of Embodiment 1 As described above, in Embodiment 1, the bubble generating mechanism 26 is provided in the oil pan 18 to promote the vaporization of the fuel in the lubricating oil in the first chamber 21 of the oil pan 18 by the bubbles. Since it did in this way, the fuel contained in lubricating oil can be efficiently isolate | separated by suppressing deterioration of oil compared with what heats lubricating oil conventionally and vaporizes and separates fuel. Further, since the oil pan 18 is provided with the first chamber 21 and the second chamber 22 partitioned from the first chamber 21, the lubricating oil in the first chamber 21 can be introduced into the second chamber 22. The lubricating oil in the chamber 21 can be guided into the second chamber 22 in a sufficiently defoamed state. As a result, it is difficult for the oil pump 36 to suck the lubricating oil mixed with air bubbles, and the occurrence of problems such as heat generation when the air bubbles are crushed and the air bubbles are crushed by the oil pressure is suppressed, and the discharge capacity of the oil pump 36 is reduced. Can be suppressed. Further, the fuel vaporized and separated from the lubricating oil is mixed with a large amount of air and blow-by gas naturally degassed from the lubricating oil, and is sent from the crank chamber 14 to the space 13 in the cylinder head cover 1d via the communication path 37. Regardless of the operating state of the engine 1, that is, the opening degree of the throttle valve 12, ventilation of the blow-by gas in the space 13 can be promoted.

  Further, in the first embodiment, the oil storage volume C1 of the first chamber 21 is made smaller than the oil storage volume C2 of the second chamber 22, so that a relatively small amount of lubricating oil is targeted in the first chamber 21. In addition to being able to separate efficiently, a relatively large amount of lubricating oil can be secured in the second chamber 22 and supplied to the lubricated part. In particular, the bottom wall 23 of the oil pan 18 is formed in a stepped shape, the bottom wall 23a of the first chamber 21 is set to a higher level than the bottom wall 23b of the second chamber 22, and the oil storage volume C1 of the first chamber 21 is set to the second level. Since it is smaller than the oil storage volume C2 of the chamber 22, the dimension of the oil pan 18 in the height direction can be made more compact.

  Further, in the first embodiment, the lubricating oil returning to the oil pan 18 is guided to the first chamber 21 through the gap between the piston 3 and the cylinder 2 that are the lubricated portions in the oil pan 18 and the crankcase 1c. Since the oil guide portion 38 is provided, the lubricating oil mixed with a relatively large amount of fuel lubricated around the piston can be guided into the first chamber 21 by the oil guide portion 38, and the lubricating oil in the lubricating oil in the first chamber 21 can be guided. The fuel separation efficiency can be further improved.

  Further, in the first embodiment, the second chamber 22 is disposed immediately below a communication path 37 formed in the cylinder block 1a and the cylinder head 1b of the engine 1 and connecting the crank chamber 14 and the space 13 in the cylinder head cover 1d. As a result, the lubricating oil in which almost no fuel is mixed can be dropped directly into the second chamber 22 by the communication path 37, and the separation efficiency of the fuel in the lubricating oil in the first chamber 21 is further improved. Can be made.

  In the first embodiment, since the first chamber 21 and the second chamber 22 are partitioned in the horizontal direction by the partition wall 24 raised from the bottom wall 23 of the oil pan 18, the dimension in the height direction of the oil pan 18 is determined. The lubricating oil in the first chamber 21 can be smoothly introduced into the second chamber 22.

  Furthermore, since the lubricating oil in the first chamber 21 is introduced into the second chamber 22 over the upper edge of the partition wall 24, the lubricating oil in a state where the bubbles are sufficiently degassed is supplied to the second chamber 22. The oil pump 36 can be introduced into the oil pump, and the decrease in the discharge capacity of the oil pump 36 can be more reliably suppressed.

(Example 2)
Next, the in-oil diluted fuel separator 40 according to the second embodiment will be described. Note that in the oil-in-diluted fuel separator 40 according to the second embodiment, the same components as those in the oil-diluted fuel separator 20 in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

(1) Structure of the oil-in-diluted fuel separator As shown in FIG. 2, the oil-in-diluted fuel separator 40 according to the second embodiment includes an oil pan 42 having a saucer-like oil container 41 at the upper center side. I have. An internal region of the oil container 41 is a first chamber 43, a lower internal region of the oil pan 18 is a second chamber 44, and the first chamber 43 and the second chamber 44 are partitioned in the vertical direction. The first chamber 43 is disposed directly below the piston 3 that is the lubricated portion.

  A bubble generating mechanism 46 that generates bubbles in the lubricating oil in the first chamber 43 is connected to the first chamber 43. The bubble generating mechanism 46 includes a plurality of bubble holes 47 formed in the bottom wall 41 a of the oil container 41. The plurality of bubble holes 47 have a diameter of about 1 mm and are formed at equal pitch intervals over the entire area of the bottom wall 41a. A lower wall 49 is provided below the bottom wall 41 a of the oil container 41 to form an air space 48 connected to each bubble hole 47. The air space 48 is connected to the other end of an air pipe 31 whose one end is connected to the compressor 30.

(2) Operation of the oil-in-diluted fuel separator Next, the operation of the oil-in-diluted fuel separator 40 having the above configuration will be described.
During engine operation, the lubricating oil that circulates around the pistons such as the crankshaft 4, the connecting rod 5, and the piston 3 as a lubricated part of the engine passes through the gap between the piston 3 and the cylinder 2 and flows through the oil container 41. It falls back into one chamber 43 and is returned. On the other hand, lubricating oil that circulates around the heads of the camshafts 10a and 10b, the drive system, etc. as the lubrication parts of the engine is formed in the cylinder block 1a and the cylinder head 1b, and the space 13 in the crank chamber 14 and the cylinder head cover 1d. Is returned to the second chamber 44 of the oil pan 42 through a communication path 37 that connects the two, or is returned to the second chamber 44 of the oil pan 42 through a chain case or a belt case (not shown) of the engine 1. .

  During engine operation, compressed air from the compressor 30 is sent to the bubble hole 47 through the open air pipe 31 and the air space 48, and a large number of bubbles are contained in the lubricating oil in the first chamber 43. Has been generated. The fuel contained in the lubricating oil in the first chamber 43 is encased in the generated bubbles or pushed up, and vaporization is promoted against the viscosity resistance of the lubricating oil.

  On the other hand, the lubricating oil from which the fuel is vaporized and separated in the first chamber 43 gets over the upper edge of the oil container 41 and falls into the second chamber 44 and is introduced. The lubricating oil in the second chamber 44 is pumped to the lubricated portion of the engine 1 through the oil passage 19 via the oil strainer 35 by the operation of the oil pump 36.

(3) Effects of Second Embodiment As described above, the second embodiment provides substantially the same operations and effects as the first embodiment, and an oil container 41 is provided in the upper part of the oil pan 42, Since the area is the first chamber 43, the internal area below the oil pan 42 is the second chamber 44, and the first chamber 43 and the second chamber 44 are partitioned in the vertical direction, the horizontal dimension of the oil pan 42 is compact. In addition, the lubricating oil in a state where the bubbles are sufficiently defoamed can be dropped into the second chamber 44 and introduced, and the reduction in the discharge capacity of the oil pump 36 can be more reliably suppressed.

  Furthermore, in the second embodiment, since the first chamber 43 is disposed directly under the piston 3 that is the lubricated portion, the lubricating oil mixed with a relatively large amount of fuel is directly dropped into the first chamber 43. The separation efficiency of the fuel in the lubricating oil in the first chamber 43 can be further improved.

In the present invention, the present invention is not limited to the first and second embodiments, and various modifications can be made within the scope of the present invention depending on the purpose and application. That is, in the first and second embodiments, a plurality of bubble holes 27 and 47 are formed in the bottom walls 23a and 41a of the first chambers 21 and 43, and one end side of each of the bubble holes 27 and 47 is the compressor 30. Although the bubble generating mechanisms 26 and 46 formed by connecting the other end side of the air pipe 31 connected to are illustrated, the present invention is not limited to this. For example, as shown in FIG. As a bubble generating mechanism 52 in which a bubble tube 51 in which one end side is connected to the other end side of the air pipe 31 connected to the compressor 30 and a plurality of nozzles for bubbles 50 is formed is disposed in the chamber 43). Good. In this case, it is preferable that the plurality of bubble nozzles 50 are formed downward. This is because the intrusion of the lubricating oil into the bubble tube 51 can be suppressed.
Examples of the arrangement form of the intake pipe 51 include a form in which a plurality of linear intake pipes 51 are provided side by side, a form in which a spiral or bellows-like intake pipe 51 is arranged, and the like. it can.

  In the first and second embodiments, the second chambers 22 and 44 are arranged immediately below the communication path 37. However, the present invention is not limited to this. For example, as shown in FIG. In addition to disposing 44 directly below the communication path 37 or replacing the second chambers 22 and 44 directly below the communication path 37, the second chambers 22 and 44 are connected to the chain case 54 of the engine 1 or You may make it arrange | position directly under a belt case.

  In the first embodiment, the oil pan 18 in which the plurality of bubble holes 27 are formed at equal pitch intervals over the entire area of the bottom wall 23a of the first chamber 21 is illustrated. As shown in FIG. 5, an oil pan 18 is formed by forming a plurality of bubble holes 27 by decreasing the number of the bottom wall 23 a of the first chamber 21 toward the side adjacent to the second chamber 22. Also good. Thereby, the lubricating oil in a state where the bubbles are more reliably degassed can be introduced into the second chamber 22.

  Further, in the first and second embodiments, the bubble generation mechanisms 26 and 46 always generate bubbles during engine operation. However, the present invention is not limited to this. For example, the rotation speed, hydraulic pressure, oil temperature, etc. of the engine 1 The electromagnetic valve 33 may be controlled to be opened and closed by the control unit 32 based on the above. As a result, the fuel can be more efficiently separated when the fuel dilution in the lubricating oil of the engine 1 is relatively large.

  In the first and second embodiments, the lubricating oil that circulates around the piston in the portion to be lubricated of the engine 1 is returned into the first chambers 21 and 43, and the lubricating oil that circulates around the head is returned to the second chamber 22. However, the present invention is not limited to this. For example, substantially all of the lubricating oil circulating through the lubricated portion of the engine 1 may be returned into the first chambers 21 and 43.

  In the first and second embodiments, a heater for heating the lubricating oil in the first chambers 21 and 43 is provided, and the fuel in the lubricating oil in the first chambers 21 and 43 is generated by the bubble generating mechanisms 26 and 46. In addition to vaporization and separation by the generated bubbles, vaporization and separation may be performed by heating a heater.

  Further, in the first and second embodiments, the mode in which the bubble generating mechanisms 26 and 46 are provided in the oil pans 18 and 42 of the wet sump engine is illustrated, but the present invention is not limited to this. For example, in the oil tank of the dry sump engine A bubble generation mechanism may be provided.

  It is widely used as a technique for separating diluted fuel contained in lubricating oil of an internal combustion engine. In particular, it is suitably used as an in-oil diluted fuel separator for a direct injection internal combustion engine that performs sub-injection before and after main injection.

1 is a longitudinal sectional view of an in-oil diluted fuel separator according to Embodiment 1. FIG. FIG. 5 is a longitudinal sectional view of a main part of an in-oil diluted fuel separator according to a second embodiment. It is a longitudinal cross-sectional view of the bubble generation mechanism of another form. It is a longitudinal cross-sectional view of the oil dilution fuel separation apparatus of another form. It is a cross-sectional view of the oil pan of other forms.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1; Engine, 3; Piston, 18, 42; Oil pan, 19; Oil passage, 20, 40; Oil-in-diluted fuel separator, 21, 43; First chamber, 22, 44; Second chamber, 26, 46 , 52; bubble generating mechanism, 36; oil passage, 38; oil guide, 41; oil container.

Claims (5)

An oil storage section that stores lubricating oil of an internal combustion engine and has a first chamber and a second chamber partitioned from the first chamber so that the lubricating oil in the first chamber can be introduced;
A bubble generating mechanism for generating bubbles in the lubricating oil in the first chamber,
An oil passage having an oil pump for supplying lubricating oil in the second chamber to a lubricated part of the internal combustion engine is disposed in the second chamber. Fuel separator.   The oil-diluted fuel separator for an internal combustion engine according to claim 1, wherein the oil storage volume of the first chamber is smaller than the oil storage volume of the second chamber.   3. The oil in the internal combustion engine according to claim 1, wherein an oil guide portion is provided in the main body of the internal combustion engine for guiding the lubricating oil that has lubricated the piston that is the lubricated portion to the first chamber. Diluted fuel separator.   The in-oil diluted fuel separation device for an internal combustion engine according to claim 1 or 2, wherein the first chamber is disposed immediately below a piston that is the lubricated portion.   5. The internal combustion engine according to claim 1, wherein the second chamber is disposed immediately below a passage for returning lubricating oil lubricated around the head as the lubricated portion to the oil storage portion. 6. Oil-diluted fuel separator.

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