Internal combustion engine

Abstract

To efficiently dissipate air bubbles included in oil circulating within an internal combustion engine.SOLUTION: An internal combustion engine includes: an oil storage part in which a suction part of oil to be supplied to each part of an internal combustion engine body is disposed; an oil flow passage in which air bubble-containing oil to be returned from each part of the internal combustion engine body to the oil storage part flows; and a high pressure part to which the oil is supplied, in which pressure becomes higher than the atmospheric pressure and that has an oil injection hole for injecting the oil toward the air bubble-containing oil flowing in the oil flow passage.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an internal combustion engine. [Background technology]

[0002] Engine oil (hereinafter simply referred to as "oil") circulates inside an internal combustion engine. Aeration may occur in the oil circulating inside the internal combustion engine. Aeration is a phenomenon in which air bubbles become mixed into the oil. Aeration reduces the oil's ability to lubricate and cool various parts inside the internal combustion engine. In the past, in order to mitigate the effects of aeration, it has been proposed to provide a baffle member having a tray section for storing oil (see, for example, Patent Document 1). The oil stored in the tray section is returned to the oil pan through an oil return hole provided in the baffle member. The oil returned to the oil pan is sucked up again by the oil strainer and circulates inside the internal combustion engine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-281177 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the proposal of Patent Document 1, air bubbles contained in the oil are reduced while the oil is stored in the tray and passes through the baffle member. However, the proposal of Patent Document 1 is a mode in which the air bubbles are left to disappear naturally. Therefore, it is expected that when the amount of air bubbles increases, the air bubbles cannot disappear quickly enough, and the proportion of air bubbles in the oil increases.

[0005] Therefore, an object of the invention disclosed in this specification is to efficiently eliminate air bubbles contained in oil circulating inside an internal combustion engine. [Means for solving the problem]

[0006] The above-mentioned object is achieved by an internal combustion engine comprising an oil reservoir in which an oil suction section is arranged for oil to be supplied to each part of the internal combustion engine body, an oil flow path through which air-containing oil flows to be returned from each part of the internal combustion engine body to the oil reservoir, and a high-pressure section in which the pressure of the oil becomes higher than atmospheric pressure as the oil is supplied, and in which an oil injection hole is provided for injecting the oil toward the air-containing oil flowing through the oil flow path.

[0007] In the internal combustion engine having the above configuration, the high pressure section may be a balancer storage chamber in which a balancer included in a balancer device is stored, and the oil injection hole may be provided in a housing that defines the balancer storage chamber.

[0008] In the internal combustion engine having the above configuration, a drive unit that rotates a balancer shaft provided in the balancer device can be accommodated in a drive unit storage chamber that is formed separately so as to be a different space from the balancer storage chamber.

[0009] In addition, in the internal combustion engine having the above configuration, the high pressure section can be an oil discharge passage through which the oil pump discharges oil sucked up from the suction section, and the oil injection hole can be provided in the oil discharge passage.

[0010] Furthermore, in the internal combustion engine having the above configuration, the oil flow path can include an inclined surface along which the bubble-containing oil returned to the oil reservoir flows, and the oil injection hole can be configured to inject the oil toward the inclined surface. Effect of the Invention

[0011] The invention disclosed in this specification can efficiently eliminate air bubbles contained in oil circulating inside an internal combustion engine. [Brief description of the drawings]

[0012] [Figure 1]FIG. 1 is a cross-sectional view of an internal combustion engine according to a first embodiment, taken along the axial direction of a crankshaft and the axial direction of a cylinder. [Diagram 2] FIG. 2 is a cross-sectional view of the internal combustion engine according to the first embodiment taken along a direction perpendicular to the axial direction of the crankshaft. [Diagram 3] Fig. 3A is an exploded view showing a state in which an upper housing is removed from the balancer device provided in the internal combustion engine of the first embodiment, and further a first balancer shaft and a second balancer shaft are removed from the lower housing. Fig. 3B is an explanatory view showing a state in which the upper housing is removed from the balancer device provided in the internal combustion engine of the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view of the balancer device taken along a direction perpendicular to the axial direction of the first balancer shaft and the second balancer shaft. [Diagram 5] Fig. 5A is a cross-sectional view of the balancer device according to the second embodiment taken along the axial direction of a second balancer shaft, and Fig. 5B is an explanatory view showing a state in which an upper housing is removed from the balancer device according to the second embodiment. [Figure 6] FIG. 6 is a cross-sectional view of an internal combustion engine according to a third embodiment taken along the axial direction of a crankshaft and the axial direction of a cylinder. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the drawings, the dimensions, ratios, and the like of each part may not be illustrated to be completely consistent with the actual ones. In some drawings, details are omitted.

[0014] (First embodiment) [Configuration of an internal combustion engine] The internal combustion engine 1 of this embodiment is an in-line four-cylinder engine for an automobile that uses gasoline as fuel. As shown in Figs. 1 and 2, the internal combustion engine 1 includes a cylinder block 2, a cylinder head 3, and a crankcase 4. The cylinder head 3 is provided above the cylinder block 2. The crankcase 4 is provided below the cylinder block 2. An oil pan 5 is provided below the crankcase 4. Note that the cylinder arrangement method and number of cylinders in the internal combustion engine, and the fuel used are not limited to those described above. Furthermore, the application of the internal combustion engine is not limited to automobiles. The internal combustion engine may also be used in ships and general machinery.

[0015] The cylinder block 2 has four cylinders 2a arranged in series. The cylinder block 2 is provided with a crankshaft 6 whose axial direction coincides with the arrangement direction of the cylinders 2a. A piston 8 is provided on a crank pin 6a of the crankshaft 6 via a connecting rod 7. Each piston 8 is provided reciprocally within the cylinder 2a. The crankshaft 6 has a first gear 9. The first gear 9 drives a first balancer shaft 30 (see Figures 3A and 3B) provided in a balancer device 20 described later.

[0016] The cylinder head 3 is provided with an intake valve and an exhaust valve that are openable and closable relative to a combustion chamber (not shown). The cylinder head 3 is provided with a valve drive mechanism that opens and closes the intake valve and the exhaust valve. The intake valve, the exhaust valve, and the valve drive mechanism are omitted in Figures 1 and 2.

[0017] The upper part of the crankcase 4 is open. The interior of the crankcase 4 is in communication with the interior of the cylinder block 2. The lower part of the crankcase 4 is open. An oil pan 5 is provided in the opening at the lower part of the crankcase 4 to cover this opening. A balancer device 20 is provided inside the crankcase 4.

[0018] The oil pan 5 corresponds to an oil storage section, and can store oil 80 therein. An oil strainer 10 corresponding to a suction section for the oil 80 is disposed inside the oil pan 5. The oil strainer 10 is connected to an oil pump 11 via an oil suction passage 12. The oil pump 11 supplies the oil 80 sucked up from inside the oil pan 5 to each section of the internal combustion engine body via an oil discharge passage 13. The oil pump 11 is driven via a sprocket provided in a valve drive mechanism. The oil pump 11 may be driven by another conventionally known mechanism.

[0019] The internal combustion engine body includes a cylinder block 2, a cylinder head 3, a crankshaft 6, an intake valve, an exhaust valve, and a valve drive mechanism. Oil 80 discharged by an oil pump 11 is supplied to each part of the internal combustion engine body. The oil 80 supplied to each part of the internal combustion engine body and used for lubrication and cooling passes through the inside of the cylinder block 2 and the crankcase 4 and is returned to the oil pan 5. The inner peripheral wall surface 4a of the crankcase 4 forms an oil flow path through which the oil 80 returned from each part of the internal combustion engine body to the oil pan 5 flows. The oil 80 supplied to each part of the internal combustion engine body may be bubble-containing oil containing air bubbles 80a. For example, the oil 80 supplied around the rotating crankshaft 6 may generate aeration and contain air bubbles 80a.

[0020] The balancer device 20 includes a first balancer shaft 30 and a second balancer shaft 35 housed in a housing 21. The housing 21 includes an upper housing 22 and a lower housing 23. Fig. 3A shows a state in which the upper housing 22 of the housing 21 has been removed. Fig. 3A further shows a state in which the first balancer shaft 30 and the second balancer shaft 35 have been removed from the lower housing 23.

[0021] The housing 21 includes a journal portion 24 that rotatably supports the first balancer shaft 30 and the second balancer shaft 35. The journal portion 24 includes an oil supply port 24a. Oil 80 is supplied to the oil supply port 24a via the oil discharge flow path 13. The oil 80 supplied to the oil supply port 24a also flows into the housing 21. The housing 21 includes a first chamber 25 and a second chamber 27. The first chamber 25 and the second chamber 27 are formed separately to be different spaces.

[0022] The first balancer shaft 30 includes a first balancer 31, a second gear 32, and a third gear 33. The first balancer 31 is an eccentric weight. The second gear 32 meshes with a first gear 9 included in the crankshaft 6. The third gear 33 meshes with a fourth gear 37, which will be described later.

[0023] The second balancer shaft 35 includes a second balancer 36 and a fourth gear 37. The second balancer 36 is an eccentric weight similar to the first balancer 31. The fourth gear 37 meshes with the third gear 33.

[0024] The second gear 32, the third gear 33 and the fourth gear 37 correspond to a drive unit that rotates the first balancer shaft 30 and the second balancer shaft 35.

[0025] The first balancer shaft 30 and the second balancer shaft 35 are installed in the housing 21 so as to be supported by the journal portion 24. At this time, the first balancer 31 and the second balancer 36 are housed in the first chamber 25 as shown by the arrow 15b. The first chamber 25 corresponds to the balancer storage chamber. The second gear 32, the third gear 33 and the fourth gear 37 are housed in the second chamber 27 as shown by the arrow 15c. The second chamber 27 corresponds to the drive unit storage chamber.

[0026] When the internal combustion engine 1 is operating, the pressure inside the first chamber 25 becomes higher than atmospheric pressure. As shown in enlarged views of part X1 in Fig. 1 and part X2 in Fig. 2, an oil ejection hole 26 is provided in a portion of the housing 21 corresponding to the first chamber 25. Oil 80 supplied into the first chamber 25 is ejected to the outside of the first chamber 25 through the oil ejection hole 26 as shown by arrow 15a.

[0027] Here, the increase in pressure in the first chamber 25 will be described with reference to FIG. 3B and FIG. 4. First, the crankshaft 6 (see FIG. 1) on which the first gear 9 is provided rotates. Then, the first balancer shaft 30 having the second gear 32 meshing with the first gear 9 rotates as shown by the arrow 15d. Then, the second balancer shaft 35 having the fourth gear 37 meshing with the third gear 33 provided on the first balancer shaft 30 rotates as shown by the arrow 15e. When the first balancer shaft 30 rotates, the first balancer 31 rotates in the first chamber 25. When the second balancer shaft 35 rotates, the second balancer 36 rotates in the first chamber 25. When the positions of the first balancer 31 and the second balancer 36, both of which are eccentric weights, change sequentially in the circumferential direction, the pressure in the internal space of the first chamber 25 increases.

[0028] Oil 80 is supplied through the oil supply port 24a into the first chamber 25. The oil 80 supplied into the first chamber 25 is jet-injected through the oil injection hole 26 from the first chamber 25, where the oil 80 has become highly pressurized.

[0029] The oil 80 is jetted toward the inner circumferential wall surface 4a of the crankcase 4. The oil 80 jetted at high pressure crushes the air bubbles 80a contained in the oil 80 flowing along the inner circumferential wall surface 4a. This causes the air bubbles contained in the oil 80 to disappear. As a result, the air bubble ratio of the oil 80 decreases.

[0030] The inner peripheral wall surface 4a includes a portion that becomes an inclined surface when the internal combustion engine 1 is mounted on a vehicle. The inclined surface is a surface other than a horizontal surface that is perpendicular to the vertical direction. A surface that includes the vertical direction can be included in the inclined surface. In other words, a surface through which the oil 80 can flow down is included in the inclined surface. The oil injection hole 26 is provided so as to inject the oil 80 toward such an inclined surface. The oil containing air bubbles is returned from the cylinder block 2 to the oil pan 5 along the inner peripheral wall surface 4a. By injecting the oil 80 toward the inner peripheral wall surface 4a including the inclined surface, the air bubbles can be efficiently crushed.

[0031] Depending on the shape of the oil pan 5, the oil 80 may be sprayed toward the oil containing air bubbles flowing along the inner peripheral wall surface of the oil pan 5.

[0032] In the balancer device 20 of this embodiment, the first chamber 25 and the second chamber 27 are provided separately. This is in consideration of the possibility that the oil 80 may foam due to the rotation of the second gear 32, the third gear 33, and the fourth gear 37, and air bubbles 80a may be mixed into the oil 80. It is preferable that the oil 80 itself, which is injected to crush the air bubbles 80a, does not contain air bubbles 80a as much as possible. In this embodiment, by providing the first chamber 25 and the second chamber 27 separately, it is possible to suppress the mixing of air bubbles 80a into the injected oil 80.

[0033] [effect] In this embodiment, a high pressure section that has a pressure higher than atmospheric pressure is provided with an oil injection hole 26. By jetting oil 80 from the oil injection hole 26 toward the air bubble-containing oil flowing through the oil flow path, the air bubbles can be crushed.

[0034] In this embodiment, the high pressure portion is the first chamber 25 which is a balancer housing chamber, and an oil injection hole 26 is provided in the housing 21 which forms the first chamber 25. In this embodiment, air bubbles 80a in the oil 80 can be efficiently crushed by utilizing the high pressure inside the first chamber 25.

[0035] In this embodiment, the first chamber 25 and the second chamber 27, which is a drive unit storage chamber, are provided separately. This makes it possible to prevent air bubbles 80a from being mixed into the oil 80 in the first chamber 25.

[0036] Second embodiment Next, a second embodiment will be described. In the second embodiment, a balancer device 50 shown in Fig. 5A is adopted instead of the balancer device 20 of the first embodiment. The balancer device 50 includes a housing 51, a first balancer shaft 60, and a second balancer shaft 65. The housing 51 includes an upper housing 52 and a lower housing 53. Fig. 5A is a cross-sectional view of the balancer device 50 taken along the axial direction of the second balancer shaft 65. Fig. 5B is an explanatory diagram showing a state in which the upper housing 52 is removed from the balancer device 50.

[0037] The first balancer shaft 60 includes a first balancer 61, a second gear 62, and a third gear 63. The first balancer 61 is an eccentric weight. The second gear 62 meshes with a first gear 9 included in the crankshaft 6. The third gear 63 meshes with a fourth gear 67, which will be described later.

[0038] The second balancer shaft 65 includes a second balancer 66 and a fourth gear 67. The second balancer 66 is an eccentric weight similar to the first balancer 61. The fourth gear 67 meshes with the third gear 63.

[0039] The second gear 62, the third gear 63, and the fourth gear 67 correspond to a drive unit that rotates the first balancer shaft 60 and the second balancer shaft 65.

[0040] The housing 51 is different from the housing 21 in the balancer device 20 of the first embodiment in that it includes a third chamber 55. The third chamber 55 is provided in place of the first chamber 25 and the second chamber 27 in the first embodiment. The third chamber 55 functions as a balancer storage chamber and a drive unit storage chamber.

[0041] The first balancer shaft 60 and the second balancer shaft 65 are installed in the housing 51 so as to be supported by the journal portion 64. At this time, the first balancer 61, the second gear 62, the third gear 63, the second balancer 66, and the fourth gear 67 are all housed in the third chamber 55.

[0042] The third chamber 55 functions as a high-pressure section. An oil ejection hole 56 is provided in the third chamber 55. When the first balancer 61 and the second balancer 66 rotate in the third chamber 55, the pressure in the third chamber 55 becomes higher than atmospheric pressure. This allows the oil in the third chamber 55 to be jet-ejected from the oil ejection hole 56. The oil 80 jet-ejected from the oil ejection hole 56 can crush the air bubbles 80a in the air-containing oil.

[0043] The balancer device 50 houses the second gear 62, the third gear 63, and the fourth gear 67 in the third chamber 55. When these drive parts are operated, air bubbles 80a may be generated in the third chamber 55. However, the pressure in the third chamber 55 is higher than the atmospheric pressure. Therefore, it is considered that the generation of air bubbles 80a is suppressed compared to the case where the oil 80 is stirred outside the third chamber 55. In addition, since the balancer device 50 combines the first chamber 25 and the second chamber 27 in the first embodiment into one, it can be configured more compactly than the balancer device 20.

[0044] Third embodiment Next, a third embodiment will be described. As shown in Fig. 6, an internal combustion engine 90 of the third embodiment includes a balancer device 91 instead of the balancer device 20 included in the internal combustion engine 1 of the first embodiment. In the balancer device 91, the oil ejection hole 26 provided in the balancer device 20 is eliminated. In the third embodiment, an oil ejection hole 14 provided in the oil discharge passage 13 is provided instead of the oil ejection hole 26.

[0045] The oil discharge flow path 13 corresponds to a high-pressure section. Oil 80 discharged from the oil pump 11 and having a pressure higher than atmospheric pressure flows through the oil discharge flow path 13. Therefore, the oil 80 is sprayed from the oil injection hole 14 as shown by the arrow 15f. The oil 80 sprayed from the oil injection hole 14 can crush the air bubbles 80a in the air-containing oil.

[0046] The above-described embodiments are merely examples for implementing the present invention, and the present invention is not limited to these. Various modifications of these embodiments are within the scope of the present invention. Furthermore, it is self-evident from the above description that various other embodiments are possible within the scope of the present invention. [Explanation of symbols]

[0047] Reference Signs List 1, 90... internal combustion engine, 4... crankcase, 4a... inner peripheral wall surface (oil flow passage), 5... oil pan, 6... crankshaft, 9... first gear, 10... oil strainer (suction portion), 11... oil pump, 12... oil suction flow passage, 13... oil discharge flow passage, 14, 26, 56... oil injection hole, 20, 50, 91... balancer device, 21, 51... housing , 25...first chamber (balancer storage chamber), 27...second chamber (drive unit storage chamber), 30, 60...first balancer shaft, 31, 61...first balancer, 32, 62...second gear, 33, 63...third gear, 35, 65...second balancer shaft, 36, 66...second balancer, 37, 67...fourth gear, 55...third chamber, 56...oil injection hole, 80...oil, 80a...air bubbles

Claims

1. an oil reservoir in which an oil suction portion for oil supplied to each portion of the internal combustion engine body is disposed; an oil flow path through which air-containing oil flows and is returned from each portion of the internal combustion engine body to the oil reservoir; a high-pressure section in which the oil is supplied and the pressure becomes higher than atmospheric pressure, and the high-pressure section is provided with an oil injection hole that injects the oil toward the air-bubble-containing oil flowing through the oil flow path; An internal combustion engine equipped with

2. The high pressure section is a balancer storage chamber in which a balancer included in a balancer device is stored, and the oil injection hole is provided in a housing forming the balancer storage chamber.

2. The internal combustion engine of claim 1.

3. A drive unit that rotates a balancer shaft provided in the balancer device is accommodated in a drive unit accommodation chamber that is formed separately from the balancer accommodation chamber so as to be a different space.

3. The internal combustion engine according to claim 2.

4. The high pressure portion is an oil discharge passage through which the oil pump discharges the oil sucked up from the suction portion, and the oil injection hole is provided in the oil discharge passage.

2. The internal combustion engine of claim 1.

5. The oil flow path includes an inclined surface along which the air-containing oil returned to the oil reservoir flows, and the oil injection hole injects the oil toward the inclined surface.

2. The internal combustion engine of claim 1.

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