JP7778003B2 - internal combustion engine - Google Patents

Description

The present invention relates to an internal combustion engine.

Internal combustion engines are known that are equipped with an oil drop passage that directs oil from the upper cylinder head to an oil sump, and a sub-oil return passage that directs oil from the oil sump into the lower crankcase. The position of the oil sump in the oil path within the cylinder block is set so that heat exchange can occur between the oil in the oil sump and the outer wall of the cylinder bore.

JP 2011-247218 A

In conventional internal combustion engines, oil absorbs heat in the oil sump. However, because the contact area between the oil flowing through the sump and the outer wall of the cylinder bore is small, the oil temperature does not rise easily.

The object of the present invention is to provide an internal combustion engine that can quickly increase the oil temperature.

To achieve the above-mentioned objective, the internal combustion engine of the present invention comprises a cylinder outer wall having a side facing outward, an opening recessed from the side and included in a passage through which oil flows, and a cover that closes the opening, and the passage includes a labyrinth portion that protrudes from at least one of the cylinder outer wall and the cover into the opening, and is provided with ribs that extend along the cylinder outer wall and in a direction intersecting the vertical direction, allowing oil to flow along the ribs.

With this configuration, the oil flows along the ribs in a direction that intersects the vertical direction, gradually moving downward. In other words, the distance the oil flows in the passage is longer than when the oil flows vertically downward at the opening. This increases the time the oil spends flowing through the passage, allowing the oil to absorb heat from the outer wall of the cylinder for a longer period of time in the passage. This promotes heat exchange between the outer wall of the cylinder and the oil, allowing the oil temperature to rise more quickly.

In addition, in the internal combustion engine according to the present invention, the passage includes multiple oil outlets that open into the interior of the opening and are connected to different flow paths.

With this configuration, oil can be discharged from multiple oil outlets at the opening where the labyrinth section is provided. As a result, oil that passes through the opening is supplied to different flow paths from the multiple oil outlets. This allows the internal combustion engine to distribute oil in different directions without providing a dedicated passage. Therefore, the internal combustion engine can reduce the number of machining points required to provide a dedicated passage, thereby reducing costs.

In addition, in the internal combustion engine according to the present invention, two of the multiple oil outlets open into the interior of the opening at both ends of the labyrinth portion in the lateral direction along the outer wall of the cylinder.

With this configuration, when oil flows through the passage, it follows the ribs provided in the labyrinth section. Two of the multiple oil outlets open into the opening at both ends of the labyrinth section in the horizontal direction along the outer wall of the cylinder, allowing the oil to flow laterally toward the two oil outlets. This allows the internal combustion engine to distribute oil in two opposite directions in the horizontal direction without providing a dedicated passage. Therefore, the internal combustion engine can reduce the number of machining steps required to provide dedicated passages, further reducing costs.

In addition, in the internal combustion engine according to the present invention, the multiple oil outlets open into the interior of the opening at different positions in the vertical direction, and at least one of the multiple oil outlets is provided on the upper surface of the rib.

With this configuration, when oil flows through the passage, it flows along the upper surface of the rib toward the oil outlet provided on the upper surface of the rib. In other words, the oil initially flows toward the oil outlet located higher among the multiple oil outlets. Then, the oil that does not fit into that oil outlet overflows and flows toward the oil outlet located lower. In this way, by providing one oil outlet at a higher position than the other oil outlet, the amount of oil flowing into one oil outlet can be made greater than the other oil outlet. This allows the internal combustion engine to adjust the amount of oil flowing into multiple oil outlets.

Furthermore, with this configuration, by providing at least one of the multiple oil outlets on the upper surface of the rib, the internal combustion engine is able to adjust the amount of oil without providing a dedicated passage. This reduces the number of machining steps required to provide a dedicated passage, further reducing costs.

In addition, in the internal combustion engine according to the present invention, the ribs include a first rib that protrudes from the outer wall of the cylinder toward the cover and is spaced apart from the cover, and a second rib that protrudes from the cover toward the outer wall of the cylinder and is spaced apart from the outer wall of the cylinder, with the upper surface of the first rib extending obliquely downward toward the cover and the upper surface of the second rib extending obliquely downward toward the outer wall of the cylinder.

With this configuration, when the internal combustion engine is stopped and oil flow stops, the oil flows downward through the gap between the first rib and the cover and the gap between the second rib and the outer wall of the cylinder. This prevents oil from stagnating in the labyrinth section.

Furthermore, with this configuration, the oil that flows down the gap between the second rib and the outer wall of the cylinder flows down along the outer wall of the cylinder. Because the oil flows down along the outer wall of the cylinder, it can absorb heat from the outer wall of the cylinder. This allows the internal combustion engine to raise the oil temperature even more quickly.

This invention allows the oil temperature to rise quickly.

FIG. 1 is a cross-sectional view showing a partial configuration of an internal combustion engine according to this embodiment. FIG. 2 is a cross-sectional view showing the internal combustion engine of this embodiment taken along line F2-F2 in FIG.

(Embodiment)
An internal combustion engine 1 according to this embodiment will be described below with reference to the drawings. The configuration of the embodiment described below, as well as the actions and results (effects) brought about by this configuration, are merely examples and are not limited to the following description. Note that in this specification, ordinal numbers are used only to distinguish between parts and members, and do not indicate order or priority.

Figure 1 is a cross-sectional view showing the configuration of a portion of an internal combustion engine 1 according to this embodiment, and Figure 2 is a cross-sectional view showing the internal combustion engine 1 of this embodiment along line F2-F2 in Figure 1. Note that the internal combustion engine 1 of this embodiment is a reciprocating engine, but is not limited to this. Furthermore, the number of cylinders in the internal combustion engine 1 is not limited.

As shown in Figure 2, the internal combustion engine 1 includes a cylinder block 2 and a cover 3. Note that the cylinder block 2 may be divided into, for example, a cylinder block and a cylinder head located above the cylinder block. The upper surface of the cylinder block 2 is covered by a head cover or the like.

As shown in Figure 1, the cylinder block 2 is provided with a cylinder bore 22. The cylinder bore 22 is a cylindrical space provided in the cylinder block 2. The cylinder bore 22 also forms a combustion chamber. The cylinder bore 22 is an example of a cylinder.

The cylinder block 2 has an outer wall 22a of the cylinder bore 22. The outer wall 22a is a part of the cylinder block 2 that defines the inner circumferential surface of the cylinder bore 22. In other words, the outer wall 22a is the part of the cylinder block 2 that surrounds the cylinder bore 22.

The cover 3 covers the opening 52 (described below), thereby including the opening 52 and forming the oil drain passage 5 through which oil flows.

The internal combustion engine 1 is also provided with an oil drop passage 5. Note that the oil drop passage 5 is one example of a passage.

The oil drop passage 5 is a passage for guiding oil that has lubricated the cylinder block 2, for example, to the bottom of the internal combustion engine 1. The oil drop passage 5 is located in a position that does not interfere with bolt holes, etc. The oil drop passage 5 has a hole portion 51, an opening portion 52, a labyrinth portion 53, and two oil outlets 54.

The hole 51 is a space that extends substantially vertically downward from the space in which the cam is disposed, for example. In this embodiment, the hole 51 is provided along the outer wall 22a of the cylinder bore 22 and approximately in the center between the cylinder bores 22 in the horizontal direction (left-right direction in FIG. 1) that is perpendicular to the up-down direction, but the position of the hole 51 is not limited to this. In this embodiment, the hole 51 is a space that extends substantially vertically downward, but the hole 51 may be inclined or curved, for example, as long as its shape allows oil to be guided downward by gravity.

The opening 52 is provided in the outer wall 22a of the cylinder bore 22. For example, as shown in FIG. 2, the outer wall 22a has a substantially flat side surface 22a1 facing outward. The opening 52 is included in the oil drop passage 5 through which oil flows. The opening 52 is a hole recessed from the side surface 22a1 toward the cylinder bore 22 and open to the outside.

The outer wall 22a has a bottom surface 22a2 of the opening 52. The bottom surface 22a2 is a roughly cylindrical curved surface that conforms to the cylinder bore 22. The opening 52 is formed by a peripheral wall 22a3 that protrudes from the bottom surface 22a2. The end surface of the peripheral wall 22a3 is the side surface 22a1.

Opening 52 is a space for temporarily storing oil flowing from hole 51. For example, hole 51 is connected to the upper end 52a of opening 52. However, hole 51 may also be connected to another part located above the lower end 52b of opening 52.

When the opening 52 is covered (blocked) by the cover 3, it functions as a passage for guiding oil downward into the internal combustion engine 1. At this time, the area between the side surface 22a1 and the cover 3 around the opening 52 is sealed, for example, by a sealing member, preventing oil from leaking from the opening 52.

The labyrinth portion 53 is provided in the opening 52. In this embodiment, the labyrinth portion 53 is included in the opening 52. The labyrinth portion 53 is provided with a plurality of ribs 531. The labyrinth portion 53 can also be referred to as, for example, a serpentine portion.

The multiple ribs 531 include a first rib 531a and a second rib 531b. The number of ribs 531 may be changed as appropriate.

The first rib 531a protrudes from the outer wall 22a of the cylinder bore 22 into the opening 52. In this embodiment, the first rib 531a protrudes from the bottom surface 22a2 of the opening 52 toward the cover 3. The first rib 531a is spaced apart from the cover 3. In other words, a gap is provided between the first rib 531a and the cover 3.

A portion of the first rib 531a is positioned below the outlet of the hole 51. The first rib 531a extends along the outer wall 22a of the cylinder bore 22 and in a direction intersecting the vertical direction of the internal combustion engine 1, allowing oil to flow along the first rib 531a. In this embodiment, the first rib 531a is inclined obliquely downward toward one end 531a1 of the first rib 531a.

The end 531a1 of the first rib 531a is located at one end of the labyrinth portion 53 in the lateral direction. The end 531a1 of the first rib 531a is connected to the peripheral wall 22a3. Note that the end 531a1 may be spaced apart from the peripheral wall 22a3.

The first rib 531a has an oil contact surface 531a2 that comes into contact with the oil flowing from the outlet of the hole 51. The oil contact surface 531a2 is the upper surface of the first rib 531a and faces generally upward. The oil contact surface 531a2 faces the outlet of the hole 51.

As shown in FIG. 2, the oil contact surface 531a2 of the first rib 531a extends obliquely downward toward the cover 3 when the opening 52 is closed by the cover 3. For example, the first rib 531a protrudes from the outer wall 22a of the cylinder bore 22 so as to taper toward the cover 3.

The second rib 531b protrudes from the cover 3 into the opening 52. In this embodiment, the second rib 531b protrudes from the cover 3 toward the bottom surface 22a2 of the opening 52. The second rib 531b is spaced apart from the outer wall 22a. In other words, a gap is provided between the second rib 531b and the outer wall 22a.

The second rib 531b is spaced downward from the first rib 531a. The second rib 531b is located between the first rib 531a and the lower end 52b of the opening 52. A portion of the first rib 531a and a portion of the second rib 531b overlap in the vertical direction.

The second rib 531b extends along the outer wall 22a of the cylinder bore 22 and in a direction intersecting the vertical direction of the internal combustion engine 1. In this embodiment, the second rib 531b extends approximately parallel to the first rib 531a. Note that the extending direction of the first rib 531a and the extending direction of the second rib 531b may be different from each other.

The second rib 531b has an oil contact surface 531b1 that comes into contact with the oil flowing from the first rib 531a. The oil contact surface 531b1 is the upper surface of the second rib 531b and faces generally upward. The oil contact surface 531b1 faces the first rib 531a.

When the opening 52 is closed by the cover 3, the oil contact surface 531b1 of the second rib 531b extends obliquely downward toward the bottom surface 22a2 of the outer wall 22a of the cylinder bore 22. For example, the second rib 531b protrudes from the cover 3 so as to taper toward the bottom surface 22a2 of the outer wall 22a.

The oil outlet 54 includes a first oil outlet 541 and a second oil outlet 542. The multiple oil outlets 54 open into the interior of the opening 52 at both ends of the labyrinth section 53 in the lateral direction and are connected to different flow paths 55.

The first oil outlet 541 is provided on the oil contact surface 531a2 of the first rib 531a, near the end 531a1 of the first rib 531a. That is, the first oil outlet 541 opens into the opening 52 at one end of the labyrinth portion 53 in the lateral direction. The first oil outlet 541 may also be provided at another position on the oil contact surface 531a2.

The second oil outlet 542 is located below the first oil outlet 541. That is, the first oil outlet 541 and the second oil outlet 542 open into the interior of the opening 52 at different positions in the vertical direction. The second oil outlet 542 opens into the peripheral wall 22a3 at the other end of the labyrinth portion 53 in the horizontal direction.

The flow path 55 includes a first flow path 551 and a second flow path 552. The first flow path 551 is connected to the first oil outlet 541 and extends downward, leading to, for example, the vicinity of the rear ball bearing 6 that supports the balance shaft. The outlet of the first flow path 551 is located above at least a portion of the rear ball bearing 6. Therefore, the first flow path 551 can supply oil to the rear ball bearing 6.

The second flow path 552 is connected to the second oil outlet 542, extends in a generally horizontal direction, and is connected, for example, to the vicinity of the front ball bearing 7 that supports the balance shaft. The outlet of the second flow path 552 is located above at least a portion of the front ball bearing 7. Therefore, the second flow path 552 can supply oil to the front ball bearing 7.

In this embodiment, the diameter of the first oil outlet 541 is smaller than the diameter of the second oil outlet 542. In other words, the cross-sectional area of the first oil outlet 541 is smaller than the cross-sectional area of the second oil outlet 542. However, the diameter of the oil outlet 54 may be changed as appropriate to correspond to the amount of oil flowing through the oil drop passage 5.

In the internal combustion engine 1 described above, for example, oil that has lubricated the interior of the cylinder block 2 flows vertically downward through the hole 51 of the oil drop passage 5. The oil flowing from the hole 51 flows into the labyrinth portion 53 of the opening 52.

Oil that flows from the outlet of the hole 51 into the opening 52 flows along the oil contact surface 531a2 of the first rib 531a located below the hole 51 toward the first oil outlet 541 located on the oil contact surface 531a2. As the oil comes into contact with the outer wall 22a of the cylinder bore 22, it receives heat from the outer wall 22a and increases in temperature. Some of the oil, whose viscosity has decreased due to the temperature increase, passes from the first oil outlet 541 through the first flow path 551 and is supplied to the rear ball bearing 6.

Meanwhile, the oil that continues to flow from the hole 51 eventually overflows from the first oil outlet 541. As a result, another portion of the oil flows to the second rib 531b located below the first rib 531a.

At this time, because the first rib 531a protrudes from the outer wall 22a of the cylinder bore 22 and the oil contact surface 531a2 is inclined diagonally downward toward the cover 3, some of the oil flows down into the gap between the first rib 531a and the cover 3. The oil may also flow downward, over the upper end of the first rib 531a.

Oil flowing from the first rib 531a flows along the oil contact surface 531b1 of the second rib 531b toward the second oil outlet 542, which is located below the first oil outlet 541. As the oil comes into contact with the outer wall 22a of the cylinder bore 22, it receives heat from the outer wall 22a and increases in temperature. The oil, whose viscosity has decreased due to the temperature increase, is supplied from the second oil outlet 542 through the second flow path 552 to the front ball bearing 7.

At this time, the second rib 531b protrudes from the cover 3, and the oil contact surface 531b1 is inclined diagonally downward toward the outer wall 22a of the cylinder bore 22, causing some of the oil to flow down into the gap between the second rib 531b and the bottom surface 22a2 of the outer wall 22a of the cylinder bore 22. As a result, the oil flows down the bottom surface 22a2 of the outer wall 22a, absorbing heat from the outer wall 22a, and flows to the second oil outlet 542.

When the internal combustion engine 1 is stopped, oil is discharged from the first oil outlet 541 to the outside of the opening 52, and is also discharged from the second oil outlet 542 through the gap between the first rib 531a and the cover 3 and the gap between the second rib 531b and the outer wall 22a of the cylinder bore 22. Therefore, the labyrinth portion 53 prevents oil from remaining in the opening 52.

As described above, the internal combustion engine 1 of this embodiment includes the outer wall 22a of the cylinder bore 22 and the cover 3. The outer wall 22a of the cylinder bore 22 has a side surface 22a1 facing outward, is included in the oil drop passage 5 through which oil flows, and has an opening 52 recessed from the side surface 22a1. The cover 3 closes the opening 52. The oil drop passage 5 includes a labyrinth portion 53. The labyrinth portion 53 has ribs 531 that protrude from at least one of the outer wall 22a of the cylinder bore 22 and the cover 3 into the opening 52, extend along the outer wall 22a of the cylinder bore 22, and extend in a direction intersecting the vertical direction, allowing oil to flow along the ribs 531.

As a result, the oil flows gradually downward along the rib 531 in a direction intersecting the vertical direction. In other words, the distance the oil flows in the oil drop passage 5 is longer than when the oil flows vertically downward at the opening 52.

As a result, the oil flows through the oil drop passage 5 for a longer period of time, allowing the oil to receive heat from the outer wall 22a of the cylinder bore 22 in the oil drop passage 5 for a longer period of time. This promotes heat exchange between the outer wall 22a of the cylinder bore 22 and the oil, allowing the oil temperature to rise more quickly.

In addition, in this embodiment, the oil drop passage 5 opens into the opening 52 and includes multiple oil outlets 54 connected to different flow paths 55.

For example, in an opening 52 provided with a labyrinth section 53, oil can be discharged from multiple oil outlets 54. Therefore, oil that passes through the opening 52 is supplied to different flow paths 55 from the multiple oil outlets 54.

This allows the internal combustion engine 1 to distribute oil in different directions without the need for dedicated passages. Therefore, the internal combustion engine 1 can reduce the number of machining steps required to create dedicated passages, thereby reducing costs.

In addition, in this embodiment, the first oil outlet 541 and the second oil outlet 542 open into the opening 52 at both ends of the labyrinth portion 53 in the horizontal direction along the outer wall 22a of the cylinder bore 22.

For example, when oil flows through the oil drop passage 5, it flows along the ribs 531 provided in the labyrinth portion 53. The first oil outlet 541 and the second oil outlet 542 open into the opening 52 at both ends of the labyrinth portion 53 in the horizontal direction along the outer wall 22a of the cylinder bore 22, so that the oil flows toward the first oil outlet 541 and the second oil outlet 542 while splitting in the horizontal direction along the outer wall 22a of the cylinder bore 22.

This allows the internal combustion engine 1 to distribute oil in two opposite lateral directions without the need for dedicated passages. Therefore, the internal combustion engine 1 can reduce the number of machining steps required to create dedicated passages, further reducing costs.

In addition, in this embodiment, the multiple oil outlets 54 open into the opening 52 at different positions in the vertical direction, and the first oil outlet 541 of the multiple oil outlets 54 is provided on the oil contact surface 531a2 of the first rib 531a.

For example, when oil flows through the oil drop passage 5, it flows along the oil contact surface 531a2 of the first rib 531a toward the first oil outlet 541 provided on the oil contact surface 531a2 of the first rib 531a. In other words, the oil initially flows toward the upper oil outlet 54 (first oil outlet 541) of the multiple oil outlets 54. Subsequently, the oil that does not fit into that oil outlet 54 overflows and flows toward the lower oil outlet 54 (second oil outlet 542). In this way, by providing one oil outlet 54 at a higher position than the other oil outlet 54, the amount of oil flowing into one oil outlet 54 can be made greater than the other oil outlet 54. This allows the internal combustion engine 1 to adjust the amount of oil flowing into the multiple oil outlets 54.

Furthermore, by providing the first oil outlet 541 of the multiple oil outlets 54 on the oil contact surface 531a2 of the first rib 531a, the internal combustion engine 1 is able to adjust the amount of oil without providing a dedicated passage. This allows the internal combustion engine 1 to reduce the number of machining points required to provide a dedicated passage, further reducing costs.

In this embodiment, the rib 531 includes a first rib 531a and a second rib 531b. The first rib 531a protrudes from the outer wall 22a of the cylinder bore 22 toward the cover 3 and is spaced apart from the cover 3. The second rib 531b protrudes from the cover 3 toward the outer wall 22a of the cylinder bore 22 and is spaced apart from the outer wall 22a of the cylinder bore 22. The oil contact surface 531a2 of the first rib 531a extends obliquely downward toward the cover 3, and the oil contact surface 531b1 of the second rib 531b extends obliquely downward toward the outer wall 22a of the cylinder bore 22.

For example, when oil flows through the oil drop passage 5, it flows over the oil contact surface 531a2 of the first rib 531a and the oil contact surface 531b1 of the second rib 531b. Because the oil contact surface 531a2 extends diagonally downward toward the cover 3, the oil flowing over the oil contact surface 531a2 of the first rib 531a flows toward the cover 3 and drops into the gap between the first rib 531a and the cover 3. Because the oil contact surface 531b1 of the second rib 531b extends diagonally downward toward the outer wall 22a of the cylinder bore 22, the oil flowing over the oil contact surface 531b1 of the second rib 531b flows toward the outer wall 22a of the cylinder bore 22 and drops into the gap between the second rib 531b and the outer wall 22a of the cylinder bore 22.

When the internal combustion engine 1 is stopped and oil flow stops, the oil flows downward through the gap between the first rib 531a and the cover 3 and the gap between the second rib 531b and the outer wall 22a of the cylinder bore 22. This prevents oil from stagnating in the labyrinth portion 53.

In addition, the oil that flows down the gap between the second rib 531b and the outer wall 22a of the cylinder bore 22 flows down along the outer wall 22a of the cylinder bore 22. Because the oil flows down along the outer wall 22a of the cylinder bore 22, it can absorb heat from the outer wall 22a of the cylinder bore 22. This makes it possible to raise the oil temperature even more quickly.

The above describes an embodiment of the present invention, but the above embodiment is merely an example and is not intended to limit the scope of the invention. The above embodiment can be implemented in a variety of other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, the specifications of each configuration, shape, and the like (structure, type, direction, format, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be modified as appropriate.

1 Internal combustion engine 22 Cylinder bore (cylinder)
22a Outer wall 22a1 Side surface 3 Cover 5 Oil drain passage (passage)
52 Opening 53 Labyrinth portion 531 Rib 531a First rib 531a2 Oil contact surface (upper surface)
531b Second rib 531b1 Oil contact surface (upper surface)
54 Oil outlet 55 Flow path

Claims (4)

an outer wall of the cylinder having an outwardly facing side, the outer wall including an oil passage and having an opening recessed from the side;
a cover that closes the opening;
Equipped with
The passage includes a labyrinth portion having ribs that protrude into the opening from at least one of the outer wall of the cylinder and the cover and extend along the outer wall of the cylinder in a direction intersecting the up-down direction, allowing the oil to flow along the ribs , and a plurality of oil outlets that open into the opening and are connected to different flow paths .
Internal combustion engine. two of the plurality of oil outlets open into the opening at both ends of the labyrinth portion in a lateral direction along the outer wall of the cylinder;
2. The internal combustion engine according to claim 1. the plurality of oil outlets open into the opening at positions different from one another in the up-down direction,
At least one of the plurality of oil outlets is provided on the upper surface of the rib.
3. An internal combustion engine according to claim 1 or 2. The rib includes a first rib that protrudes from the outer wall of the cylinder toward the cover and is spaced apart from the cover, and a second rib that protrudes from the cover toward the outer wall of the cylinder and is spaced apart from the outer wall of the cylinder,
an upper surface of the first rib extends obliquely downward toward the cover;
The upper surface of the second rib extends obliquely downward toward the outer wall of the cylinder.
An internal combustion engine according to any one of claims 1 to 3.