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 Art

[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 are mixed into the oil. Aeration reduces the function of the oil that lubricates and cools each part inside the internal combustion engine. Conventionally, in order to mitigate the influence of aeration, a proposal has been made to equip a baffle member having a tray portion for storing oil (see, for example, Patent Document 1). The oil stored in the tray portion 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 an oil strainer and circulates inside the internal combustion engine.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the proposal of Patent Document 1, the air bubbles contained in the oil decrease while the oil is stored in the tray portion and passes through the baffle member. However, the proposal of Patent Document 1 is in a mode of waiting for the air bubbles to disappear naturally. Therefore, when the amount of air bubbles increases, it is assumed that the disappearance of the air bubbles cannot catch up and the existence ratio of the air bubbles in the oil becomes high.

[0005] Therefore, the invention disclosed in this specification aims to efficiently eliminate the air bubbles contained in the oil circulating inside the internal combustion engine.

Means for Solving the Problems

[0006] The above problem is solved by an internal combustion engine comprising: an oil reservoir where suction ports for oil supplied to each part of the internal combustion engine body are located; an oil passage through which bubble-containing oil flows back from each part of the internal combustion engine body to the oil reservoir; and a high-pressure section where the oil is supplied and the pressure becomes higher than atmospheric pressure, and an oil injection port is provided for injecting the oil into the bubble-containing oil flowing through the oil passage.

[0007] In the internal combustion engine with the above configuration, the high-pressure section is a balancer housing chamber in which a balancer provided in a balancer device is housed, and the oil injection holes can be provided in the housing that forms the balancer housing chamber.

[0008] In the internal combustion engine with the above configuration, the drive unit that rotates the balancer shaft provided in the balancer device may be housed in a drive unit housing chamber that is formed separately from the balancer housing chamber, creating a different space.

[0009] Furthermore, in the internal combustion engine with the above configuration, the high-pressure section is an oil discharge passage through which the oil pump discharges the oil drawn up from the suction section, and the oil injection holes can be provided in the oil discharge passage.

[0010] Furthermore, in the internal combustion engine with the above configuration, the oil passage may include an inclined surface through which the bubble-containing oil, which is returned to the oil reservoir, flows down, and the oil injection holes may be configured to inject the oil toward the inclined surface. [Effects of the Invention]

[0011] The invention disclosed herein can efficiently eliminate air bubbles contained in oil circulating within an internal combustion engine. [Brief explanation of the drawing]

[0012] [Figure 1]Figure 1 is a cross-sectional view of the internal combustion engine of the first embodiment, taken along the axial direction of the crankshaft and the axial direction of the cylinder. [Figure 2] Figure 2 is a cross-sectional view of the internal combustion engine of the first embodiment, taken along a direction perpendicular to the axial direction of the crankshaft. [Figure 3] Figure 3A is an exploded view showing the balancer device of the internal combustion engine of the first embodiment with the upper housing removed, and the first and second balancer shafts removed from the lower housing. Figure 3B is an explanatory diagram showing the balancer device of the internal combustion engine of the first embodiment with the upper housing removed. [Figure 4] Figure 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. [Figure 5] Figure 5A is a cross-sectional view of the balancer device in the second embodiment, taken along the axial direction of the second balancer shaft. Figure 5B is an explanatory diagram showing the balancer device in the second embodiment with the upper housing removed. [Figure 6] Figure 6 is a cross-sectional view of the internal combustion engine of the third embodiment, taken along the axial direction of the crankshaft and the axial direction of the cylinder. [Modes for carrying out the invention]

[0013] Embodiments of the present invention will be described below with reference to the accompanying drawings. In the drawings, the dimensions, proportions, etc., of each part may not be shown to be exactly the same as those of the actual parts. In some drawings, details are omitted.

[0014] (First Embodiment) [Configuration of an internal combustion engine] The internal combustion engine 1 of this embodiment is a gasoline-fueled inline four-cylinder engine for automobiles. As shown in Figures 1 and 2, the internal combustion engine 1 comprises a cylinder block 2, a cylinder head 3, and a crankcase 4. The cylinder head 3 is located on the upper side of the cylinder block 2. The crankcase 4 is located on the lower side of the cylinder block 2. An oil pan 5 is located on the lower side of the crankcase 4. The cylinder arrangement, number of cylinders, and fuel used in the internal combustion engine are not limited to these. 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 comprises four cylinders 2a arranged in series. The cylinder block 2 is provided with a crankshaft 6 whose axial direction is aligned with the arrangement direction of the cylinders 2a. A piston 8 is attached to the crankpin 6a of the crankshaft 6 via a connecting rod 7. Each piston 8 is reciprocally mounted within the cylinder 2a. The crankshaft 6 is equipped with a first gear 9. The first gear 9 drives the first balancer shaft 30 (see Figures 3A and 3B) of the balancer device 20, which will be described later.

[0016] The cylinder head 3 includes an intake valve and an exhaust valve that are openable and closable relative to a combustion chamber (not shown). The cylinder head 3 also includes a valve drive mechanism for opening and closing the intake valve and exhaust valve. In Figures 1 and 2, the intake valve, exhaust valve, and valve drive mechanism are omitted.

[0017] The top of the crankcase 4 is open. The inside of the crankcase 4 is in communication with the inside of the cylinder block 2. The bottom of the crankcase 4 is open. An oil pan 5 is provided to close the opening at the bottom of the crankcase 4. A balancer device 20 is provided inside the crankcase 4.

[0018] The oil pan 5 corresponds to an oil storage portion and can store oil 80 therein. Inside the oil pan 5, an oil strainer 10 corresponding to a suction portion of the oil 80 is disposed. 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 from inside the oil pan 5 to each part 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 also be driven by other conventionally known mechanisms.

[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. Each part of these internal combustion engine bodies is supplied with the oil 80 discharged by the oil pump 11. 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 into the oil pan 5. The inner peripheral wall surface 4a of the crankcase 4 forms an oil passage 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 a bubble-containing oil containing bubbles 80a. For example, the oil 80 supplied around the rotating crankshaft 6 may generate aeration and contain bubbles 80a.

[0020] The balancer device 20 includes a first balancer shaft 30 and a second balancer shaft 35 housed in a housing 2.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 is removed. FIG. 3A further shows a state in which the first balancer shaft 30 and the second balancer shaft 35 are removed from the lower housing 23.

[0021] The housing 21 includes journal sections 24 that rotatably support the first balancer shaft 30 and the second balancer shaft 35, respectively. The journal sections 24 include an oil supply port 24a. Oil 80 is supplied to the oil supply port 24a via an oil discharge passage 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 form different spaces.

[0022] The first balancer shaft 30 comprises 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 the first gear 9 on the crankshaft 6. The third gear 33 meshes with the 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 that of 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 the 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 section 24. At this time, the first balancer 31 and the second balancer 36 are housed in the first chamber 25 as indicated by arrow 15b. The first chamber 25 corresponds to the balancer housing chamber. The second gear 32, the third gear 33 and the fourth gear 37 are housed in the second chamber 27 as indicated by arrow 15c. The second chamber 27 corresponds to the drive unit housing chamber.

[0026] When the internal combustion engine 1 is operating, the pressure inside the first chamber 25 is higher than atmospheric pressure. As shown in the enlarged view of part X1 in Figure 1 and part X2 in Figure 2, an oil injection hole 26 is provided in the part of the housing 21 corresponding to the first chamber 25. The oil 80 supplied into the first chamber 25 is injected to the outside of the first chamber 25 through the oil injection hole 26, as indicated by arrow 15a.

[0027] Here, with reference to Figures 3B and 4, we will explain how the pressure inside the first chamber 25 increases. First, the crankshaft 6 (see Figure 1), on which the first gear 9 is attached, rotates. Then, the first balancer shaft 30, which has a second gear 32 that meshes with the first gear 9, rotates as indicated by arrow 15d. Next, the second balancer shaft 35, which has a fourth gear 37 that meshes with the third gear 33 on the first balancer shaft 30, rotates as indicated by arrow 15e. When the first balancer shaft 30 rotates, the first balancer 31 rotates inside the first chamber 25. When the second balancer shaft 35 rotates, the second balancer 36 rotates inside the first chamber 25. As 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 inside the first chamber 25 increases.

[0028] Oil 80 is supplied into the first chamber 25 through the oil supply port 24a. The oil 80 supplied into the first chamber 25 is jet-injected from the high-pressure first chamber 25 through the oil injection port 26.

[0029] The oil 80 is injected toward the inner circumferential wall surface 4a of the crankcase 4. The high-pressure jet injection of oil 80 crushes the air bubbles 80a contained in the oil 80 as it flows along the inner circumferential wall surface 4a. As a result, the air bubbles in the oil 80 disappear. Consequently, the air bubble ratio of the oil 80 decreases.

[0030] The inner circumferential wall surface 4a includes a portion that becomes an inclined surface when the internal combustion engine 1 is mounted on a vehicle. An inclined surface is a surface other than a horizontal plane perpendicular to the vertical direction. Surfaces that include the vertical direction can be included as inclined surfaces. In short, any surface on which oil 80 can flow is included as an inclined surface. The oil injection holes 26 are provided to inject oil 80 toward such an inclined surface. The bubble-containing oil is returned from the cylinder block 2 to the oil pan 5 via the inner circumferential wall surface 4a. By injecting oil 80 toward the inner circumferential wall surface 4a, which includes the inclined surface, the bubbles can be efficiently crushed.

[0031] Depending on the shape of the oil pan 5, the oil 80 may be sprayed towards the bubble-containing oil flowing along the inner circumferential wall surface of the oil pan 5.

[0032] In this embodiment, the balancer device 20 is provided with a first chamber 25 and a second chamber 27 separated. This is because the rotation of the second gear 32, third gear 33, and fourth gear 37 causes the oil 80 to foam, and there is a possibility that 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, contains as few air bubbles 80a 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] This embodiment includes an oil injection port 26 in the high-pressure section, which is at a pressure higher than atmospheric pressure. By jetting oil 80 from the oil injection port 26 towards the bubble-containing oil flowing through the oil passage, the bubbles can be crushed.

[0034] In this embodiment, the high-pressure section is designated as the first chamber 25, which is a balancer housing, and an oil injection hole 26 is provided in the housing 21 that forms the first chamber 25. This embodiment utilizes the high pressure inside the first chamber 25 to efficiently crush air bubbles 80a in the oil 80.

[0035] In this embodiment, the first chamber 25 and the second chamber 27, which houses the drive unit, are provided separately. This makes it possible to suppress the mixing of air bubbles 80a into the oil 80 in the first chamber 25.

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

[0037] The first balancer shaft 60 comprises 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 the first gear 9 on the crankshaft 6. The third gear 63 meshes with the 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 that of 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 the drive unit that rotates the first balancer shaft 60 and the second balancer shaft 65.

[0040] Unlike the housing 21 in the balancer device 20 of the first embodiment, the housing 51 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 section 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. The third chamber 55 is provided with an oil injection port 56. As the first balancer 61 and the second balancer 66 rotate within the third chamber 55, the pressure within the third chamber 55 becomes higher than atmospheric pressure. This allows the oil in the third chamber 55 to be jet-injected from the oil injection port 56. The oil 80 jet-injected from the oil injection port 56 can crush the air bubbles 80a in the air bubble-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 units are in operation, it is conceivable that bubbles 80a may be generated in the third chamber 55. However, the pressure inside the third chamber 55 is higher than atmospheric pressure. Therefore, compared to the case where the oil 80 is agitated outside the third chamber 55, the generation of bubbles 80a is expected to be suppressed. Furthermore, 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 Figure 6, the internal combustion engine 90 of the third embodiment is equipped with a balancer device 91 in place of the balancer device 20 provided in the internal combustion engine 1 of the first embodiment. In the balancer device 91, the oil injection holes 26 that were provided in the balancer device 20 have been eliminated. The third embodiment is equipped with oil injection holes 14 provided in the oil discharge passage 13 in place of the oil injection holes 26.

[0045] The oil discharge passage 13 corresponds to the high-pressure section. Oil 80, discharged from the oil pump 11 and now at a pressure higher than atmospheric pressure, flows through the oil discharge passage 13. As a result, the oil 80 is injected from the oil injection holes 14, as indicated by arrow 15f. The oil 80 injected from the oil injection holes 14 can crush the air bubbles 80a in the air bubble-containing oil.

[0046] The embodiments described above are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention, and it is obvious from the above description that various other embodiments are possible within the scope of the present invention. [Explanation of Symbols]

[0047] 1, 90…Internal combustion engine, 4…Crankcase, 4a…Inner circumferential wall (oil passage), 5…Oil pan, 6…Crankshaft, 9…First gear, 10…Oil strainer (suction section), 11…Oil pump, 12…Oil suction passage, 13…Oil discharge passage, 14, 26, 56…Oil injection holes, 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 port, 80...Oil, 80a...Air bubbles

Claims

1. An oil reservoir is located where the oil intake ports for supplying oil to various parts of the internal combustion engine body are situated, An oil passage through which bubble-containing oil flows, which is returned from various parts of the internal combustion engine body to the oil reservoir, The system includes a high-pressure section to which the oil is supplied and the pressure becomes higher than atmospheric pressure, and which is provided with oil injection holes for injecting the oil into the bubble-containing oil flowing through the oil passage. The high-pressure section is an oil discharge passage through which the oil pump discharges the oil drawn up from the suction section, and the oil injection holes are provided in the oil discharge passage. Internal combustion engine.

2. The oil passage includes an inclined surface through which the bubble-containing oil flows back to the oil reservoir, and the oil injection holes inject the oil toward the inclined surface. The internal combustion engine according to claim 1.

Images