JP2024044643A - engine - Google Patents

Abstract

[Problem] An engine capable of quickly raising the temperature of oil without using an external heating source is disclosed. [Solution] A strainer 14 is disposed in the deep bottom 10 of an oil pan. An oil return section 16 is disposed behind the strainer 14. A heat pipe 17, in which a heat transfer medium (fluid) is sealed inside the pipe, is disposed so that a heat receiving section 17a is located in the oil return section 16 and a heat radiating section 17b is located near the lower end of the strainer 14. Heat is exchanged between the return oil, which has been circulating around the engine and is heating up, and the oil being drawn into the strainer 14. This causes a phenomenon similar to that in which the return oil is directly drawn into the strainer 14, allowing the temperature of the oil circulating around the engine to be raised quickly. As a result, friction in the sliding parts of the engine can be reduced early, contributing to improved fuel efficiency. [Selected Figure] Figure 2

Description

The present invention relates to an engine (internal combustion engine), and is characterized by a lubricating oil storage device.

Engines use oil for lubrication and other purposes, and this oil is stored in an oil pan. The oil stored in the oil pan is then sent to each part of the engine via an oil pump, and the oil that has completed its lubrication and other functions is returned to the oil pan through oil drainage passages provided in the cylinder head and cylinder block (some oil, such as piston cooling oil jets, flows down to the oil pan without passing through the oil drainage passages).

Now, since the viscosity of oil is inversely proportional to temperature, there is a problem that the viscosity of the oil is high when starting in a low-temperature environment, which increases friction and worsens fuel economy. Therefore, measures have been proposed to reduce friction by quickly raising the temperature of the oil.

As an example, Patent Document 1 discloses that, for the oil pan of an automobile engine, a heat sink made of a material with excellent thermal conductivity, such as aluminum, is placed under the oil pan, and a thermoactuator is used to change the position of the heat sink so that when the oil is cold, a space is created between the heat sink and the oil, and when the oil is hot, the heat sink is in close contact with the underside of the oil pan.

Japanese Patent Application Publication No. 2014-43835

One method for quickly heating the oil is to use an electric heater, but this has the problem of being costly. Also, because it requires electricity as a heat source, it is difficult to determine whether or not it contributes to improving fuel efficiency. In contrast, if the oil that has heated up as it circulates around the engine can be quickly sucked up by a strainer, it can be said that the oil can be heated quickly and contribute to improving fuel efficiency.

In light of this, we have found that oil is sucked up by a strainer, but in the oil pan of a vehicle engine, the strainer is located in the deepest part of the oil pan so that oil can be reliably sucked up even if the vehicle is driving uphill or the oil level drops. However, the oil drain passage is located away from the strainer on part of the outer periphery of the oil pan, making it difficult for the strainer to quickly suck up heated oil, and so oil that is not very heated is sucked up by the strainer.

Patent Document 1 focuses on heat dissipation from the oil pan, and suppresses heat dissipation from the oil pan when the oil is low temperature, and promotes heat dissipation from the oil pan using running wind when the oil becomes high temperature. Although it can be understood that even if there is a gap between the oil pan and the heat sink, it does not affect the temperature of the oil sucked up from the strainer, but instead causes the strainer to suck up the oil whose temperature gradually rises. Therefore, it is presumed that it does not contribute much to the early reduction of friction in low-temperature environments.

The present invention was made against this background, and aims to quickly reduce friction during low-temperature startup by effectively using a heat conductor (heat exchange member) such as a heat pipe.

The present invention is as defined in claim 1.
"An engine having an oil pan for storing oil, a strainer for sucking up oil from the bottom of the oil pan, and an oil return section through which reflux oil that has been heated through the engine flows into the oil pan,
A heat conductor having a heat receiving portion located above and a heat radiating portion located below is disposed in the oil pan such that the heat receiving portion is in contact with the oil flowing down from the oil return portion, and the heat radiating portion is in contact with the oil sucked into the strainer.
The structure is as follows.

The present invention includes various configurations. As an example, the invention of claim 2 is:
"The thermal conductor is a heat pipe, and the heat pipe has a horizontal part and an inclined part extending from one end of the horizontal part toward the bottom of the oil pan, and the heat pipe has a horizontal part. The end portion of the inclined portion serves as the heat receiving portion, and the end portion of the inclined portion serves as the heat radiating portion.”
The structure is as follows.

The invention of claim 3 is the same as claim 1 or 2,
"A portion of the heat conductor is connected to a baffle plate disposed inside the oil pan."
The structure is as follows.

In the present invention, the heat of the recirculated oil that has been heated around the engine is transferred to the oil sucked into the strainer via the heat conductor. Therefore, it is possible to create a situation similar to that in which the oil returned from the engine is directly sucked up by a strainer, and to quickly raise the temperature of the oil circulating in the engine. As a result, even when starting in a low-temperature environment, friction in the sliding parts can be reduced quickly, contributing to improved fuel efficiency.

If engine rotation can be stabilized by reducing the friction of the sliding parts of the engine, it becomes possible to supply EGR gas earlier. Therefore, in the present invention, it is possible to promote cleaner exhaust gas, and it is also possible to improve fuel efficiency through early injection of EGR gas.

Heat pipes, in which a heat transfer fluid is sealed inside the pipe, have excellent heat transfer efficiency and are suitable as heat conductors. And, as in claim 2, by making the horizontal part of the heat pipe the heat receiving part and the tip of the inclined part the heat dissipating part, the return oil can be brought into contact over a wide area of the horizontal part, increasing the amount of heat received, while by positioning the tip of the inclined part close to the strainer, heat can be efficiently exchanged with the oil sucked into the strainer.

A baffle plate is placed in the oil pan to prevent oil from splashing up, but if the baffle plate supports a heat conductor such as a heat pipe as in claim 3, the structure can be simplified accordingly. can be converted into Furthermore, since the temperature of the baffle plate is raised by the oil jet for cooling the piston, heat is transferred from the baffle plate etc. to a heat conductor such as a heat pipe, which further contributes to raising the temperature of the oil.

In addition, the baffle plate needs to be provided with ribs to connect the thermal conductor, which also contributes to improving the strength of the baffle plate.

FIG. 2 is a plan view of the first embodiment. FIG. 2 is a longitudinal cross-sectional side view taken along II-II in FIG. 1; FIG. 2 is a sectional view taken along III-III in FIG. 1; (A) is a sectional view of a main part of a second embodiment, and (B) is a sectional view of a main part of a third embodiment. FIG. 4 is a diagram showing a fourth embodiment, in which (A) is a longitudinal side view, and (B) is a BB cross-sectional view of (A). FIG. 13 is a plan view of the fifth embodiment.

Next, embodiments of the present invention will be described based on the drawings. In the following, words such as "front and rear" and "left and right" are used to specify the direction, but the direction of the crank axis is taken as the front and rear direction. Regarding the front and rear, the side where the timing chain is placed is the front, and the side where the transmission case is placed is the back. This embodiment is applied to an automobile engine, and the engine is mounted horizontally in the engine room with the crank axis elongated in the vehicle width direction, and the exhaust side is directed toward the front of the vehicle body, and the engine is placed on the intake side. is facing toward the rear of the vehicle.

(1).Structure of the first embodiment First, the first embodiment shown in FIGS. 1 to 3 will be described. The engine of this embodiment has three cylinders, and the three cylinder bores 1 are shown in dashed lines in FIG. 1, and the three pairs of crank arms 2 are shown in dashed lines in FIG. They are actually out of phase, but are shown at the same height for convenience.)

The oil pan is fixed to the underside of the cylinder block (not shown) that constitutes the engine body. A front cover (not shown) that covers the timing chain is fixed to the front of the cylinder block (and cylinder head). In this embodiment, the entire front cover is located above the oil pan, but the lower part of the front cover may be overlapped and fixed to the front of the oil pan.

The oil pan has left and right side walls 3, a front wall 4, a rear wall 5, and a bottom plate 6, and is open upward, and has a flange 7 around the entire circumference at the upper edge for fixing to the cylinder block. It is formed by The lower half of the transmission case is fixed to the rear wall 5. The oil pan of this embodiment is a metal casting or die casting product, or a resin molding product.

As mentioned above, the engine of this embodiment has a front exhaust, so as shown in FIG. 2, a notch 9 in which the horizontal part of the exhaust pipe 8 is placed is formed in a carved state in about half of the underside of the rear side. Therefore, the bottom plate 6 is composed of a deep bottom part 10 located on the front side, a shallow bottom part 11 located on the rear side, and a step part 12 connecting the two. In a plan view, the second cylinder bore 1 and the step part 12 overlap.

A deep bottom portion 10 of the oil pan serves as an oil reservoir 13, and a strainer 14 is disposed in front of the oil reservoir 13. Although the strainer 14 is arranged at the middle between the left and right sides of the oil reservoir 13, it can be moved toward the exhaust side or the intake side. Further, the front and back positions of the strainer 14 can also be set arbitrarily.

The upper end 14a of the strainer 14 is connected to an oil pump via a bracket. The oil pump can be either a direct-coupled type in which a rotor is provided on the crankshaft, or a type in which the rotating shaft is driven by the crankshaft via a chain or the like. In the case of the direct connection type, the front cover also serves as the pump housing.

In FIG. 1, the upper end 14a of the strainer 14 is indicated by a chain line, and as can be understood from this display, the strainer 14 is in an inclined position when viewed from the front. This is to prevent the upper end 14a of the strainer 14, the bracket, etc. from interfering with block side members such as the crank arm 2.

As shown by the dashed line in FIG. 2, an oil drop passage 15 is formed in the exhaust side wall of the cylinder block, and the lower part of the oil drop passage 15 serves as an oil return portion 16 of the oil pan. In the embodiment, the oil drop passage 15 is located outside the inter-bore area between the second cylinder bore 1 and the third cylinder bore 1, and is closer to the exhaust side of the inner peripheral surface of the oil pan. . The oil return portion 16 is located near the connecting portion between the shallow bottom portion 11 and the stepped portion 12. Therefore, the recirculated oil quickly flows into the deep bottom portion 10.

In this embodiment, a heat pipe 17 is used as a heat conductor. The heat pipe 17 has a fluid (heat transfer medium) that controls heat transfer sealed inside the pipe, and one end is a heat receiving part 17a, and the other end is a heat radiating part 17b. The heat receiving part 17a is arranged in the oil return part 16, and the heat radiating part 17b is arranged near the lower end of the strainer 14. Therefore, the height of the heat receiving part 17a is high, and the heat receiving part 17a is located above the oil pan. On the other hand, the height of the heat radiation part 17b is low, and the heat radiation part 17b is located below the oil pan.

The heat pipe 17 also has a horizontal portion 17c, the tip of which is the heat receiving portion 17a, and an inclined portion 17d that extends diagonally downward from the end of the horizontal portion 17c. The horizontal portion 17c forms the heat receiving portion 17a. The inclined portion 17d extends from one end of the horizontal portion 17c toward the deep bottom portion 10 of the oil pan. The end of the inclined portion 17d (the end opposite the horizontal portion 17c) forms the heat dissipation portion 17b. Furthermore, since the oil return portion 16 is closer to the exhaust side, while the strainer 14 is located in the middle of the deep bottom portion 10, the horizontal portion 17c of the heat pipe 17 is bent in a U-shape in a plan view, and the inclined portion 17d is straight in a plan view. The heat dissipation section 17b of the heat pipe 17 (the end of the inclined section 17d) is provided with multiple fins 18 to promote heat transfer, but it is also possible to provide fins 18 on the heat receiving section 17a (horizontal section 17c).

As shown in FIG. 3, the horizontal portion 17c of the heat pipe 17 is fixed to a boss portion 19 provided on the side wall 3 of the oil pan with a screw 21 via a bracket 20. As shown in FIG. In this embodiment, the bracket 20 is configured in a cantilever shape with a folded metal plate or resin plate, and is fixed to the boss portion 19 with screws 21 while holding the horizontal portion 17c of the heat pipe 17. There is. It is also possible to erect a columnar boss part from the stepped part 12 of the oil pan and fix the horizontal part 17c to the upper surface of the boss part 19 with a presser member and screws 21, but in this embodiment, A cantilever-shaped bracket 20 is used so as not to obstruct the flow of circulating oil.

As shown in FIG. 2, the entire horizontal part 17c of the heat pipe 17 is located above the oil reservoir part 13, and the heat receiving part 17a is arranged in the oil return part 16, so that the oil flowing back from the oil return part 16 flows. exposed to (contact with oil). The end of the inclined part 17d of the heat pipe 17 is located at the deep bottom part 10 (oil reservoir part 13) of the oil pan, and the heat dissipation part 17b is arranged near the lower end of the strainer 14 so that the heat flows into the strainer 14. in contact with oil.

(2) Summary of the First Embodiment In the above configuration, the oil returned to the oil return section 16 is heated by frictional heat at the sliding section, and is also heated by passing through the exhaust side of the cylinder head. The heat of the heated returned oil is transferred to the heat receiving section 17a of the heat pipe 17, and then transferred to the heat dissipating section 17b through the medium sealed in the heat pipe 17, and then transferred to the oil flowing into the strainer 14.

As a result, the temperature of the oil sucked into the strainer 14 rises, but the temperature rises due to heat exchange, and the oil sucked into the strainer 14 circulates around the engine and rises in temperature, causing the temperature of the oil sucked into the heat pipe 17 to rise again. By repeating this cycle, the temperature of the oil circulating in the engine is accelerated, and the friction of each sliding part is quickly reduced, contributing to improved fuel efficiency. In addition, since operation is stable even at low speeds, it is possible to introduce EGR gas early, and as a result, it is possible to enjoy the effects of promoting exhaust gas purification and improving fuel efficiency due to the EGR system.

Now, the oil used in the piston cooling oil jets and the oil that seeps out from the sliding parts of the crankshaft flow down into the oil pan, but most of the oil that returns to the oil pan is oil that flows back from the oil drop passage 15, and the oil that returns to the oil return section 16 tends to flow toward the strainer 14 due to the pushing action of the flow and the pulling action of the strainer 14. In other words, there is a main flow that flows from the oil return section 16 toward the strainer 14, as shown by the arrow 22.

In the present embodiment, the heat dissipation section 17b of the heat pipe 17 is located around the inlet of the strainer 14 in a direction facing the oil return section 16, so that the heat dissipation section 17b is exposed to the mainstream 22 of oil. Therefore, heat can be efficiently transferred to the oil sucked into the strainer 14. Therefore, the heat exchange efficiency of the heat pipe 17 is increased, greatly contributing to early reduction of friction. It is preferable to provide the fins 18 on the heat radiating portion 17b as in the embodiment, since the heat exchange performance can be further improved.

(3) Other embodiments Next, other embodiments will be described with reference to Fig. 4 and subsequent figures. In the second embodiment shown in Fig. 4(A), the heat radiating portion 17b of the heat pipe 17 is disposed below the strainer 14. The heat radiating portion 17b is in a horizontal position. In this embodiment, the exposure function of the heat radiating portion 17b to the oil sucked into the strainer 14 is improved, so that the heat exchange performance can be further improved.

In the fourth embodiment shown in FIG. 4(B), the heat radiating part 17b is arranged below the strainer 14 while maintaining its inclined position. In this case, the lower part of the strainer 14 in the deep bottom part 10 is formed into a recess 10a to allow the heat radiation part 17b to enter. In this example as well, the function of exposing the heat radiating portion 17b to the oil sucked into the strainer 14 is enhanced.

In the fourth embodiment shown in FIG. 5, a baffle plate 23 is arranged inside the oil pan, and a horizontal portion 17c of the heat pipe 17 is suspended by a plurality of hanging pieces (ribs) 24 provided downwardly protruding from the baffle plate 23. I support you. The baffle plate 23 is shaped to generally close the oil pan, but is notched at the oil return portion 16, so that oil flows downward from the oil return portion 16 to the bottom of the baffle plate 23.

The baffle plate 23 is fixed to a plurality of bosses 25 provided in the oil pan with screws 26. Although not shown, the baffle plate 23 is provided with an opening for allowing oil to escape downward.

The planar shape of the heat pipe 17 is the same as in the first embodiment. The hanging piece 24 is formed in an upward hook shape, and by narrowing the opening, the horizontal part 17c of the heat pipe 17 is forcibly inserted against elasticity. The baffle plate 23 is made of, for example, synthetic resin, and has a slit 27 created to form the hanging piece 24 by injection molding. By bringing the oil flowing down from the slit 27 into contact with the horizontal part 17c of the heat pipe 17, the horizontal part 17c can be heated. Therefore, the amount of heat directed to the heat dissipation part 17b can be increased.

The baffle plate 23 can also be made of a metal plate. In this case, the heat of the baffle plate 23 can be efficiently transferred to the horizontal portion 17c. If the baffle plate 23 is made of a metal plate, the suspension piece 24 can be formed by cutting and raising, or can be made separately and welded.

As in this embodiment, when the heat pipe 17 is connected to the baffle plate 23, the heat of the baffle plate 23 or the heat of the oil flowing down onto it can be effectively utilized. Also, since it is not necessary to provide a support means such as a boss portion 19 on the oil pan, the structure of the oil pan can be prevented from becoming complicated. Furthermore, in this embodiment, the strainer 14 is cut obliquely to open widely toward the main flow 22 of the oil so that the main flow 22 of the oil can flow efficiently into the lower end of the strainer 14. Therefore, the heat dissipation portion 17b of the heat pipe 17 is strongly exposed to the main flow 22 of the oil.

In the fifth embodiment shown in FIG. 6, an oil drop passage 15 and an oil return section 16 are arranged on each side of the two bore spaces. Therefore, the heat pipe 17 has the entire horizontal section 17c as the heat receiving section 17a. Many engines are equipped with multiple oil drop passages 15, but by exposing the heat receiving section 17a of the heat pipe 17 to multiple flows of return oil, the heat exchange performance can be greatly improved. When there are multiple oil drop passages 15 and oil return sections 16, multiple heat pipes 17 may be arranged.

In this embodiment, the heat pipe 17 has the entire horizontal section 17c as the heat receiving section 17a, but it is also possible to arrange the entire pipe in an inclined position without forming the horizontal section 17c, with the heat receiving section 17a at the top and the heat dissipation section 17b at the bottom. It is also possible to provide the heat receiving section 17a at the inclined top and the horizontal heat dissipation section 17b at the bottom as shown in Figure 4(A).

Furthermore, in this embodiment, the horizontal portion 17c of the heat pipe 17 is connected to the baffle plate 23, but the inclined portion 17d of the heat pipe 17 may be connected to the baffle plate 23, or the horizontal portion 17c and Both the inclined portion 17d and the heat pipe 17d may be connected to the baffle plate 23 (if the entire heat pipe 17 is inclined as described above, the inclined portion is naturally connected to the baffle plate 23).

Although the embodiments of the present invention have been described above, the present invention can be embodied in various other ways. For example, when a baffle plate is provided, it is also possible to form a gutter-like part that sends the returned oil to the left and right intermediate parts of the oil pan, and to arrange the horizontal part of the heat pipe 17 inside the gutter-like part.

The present invention can be embodied in an engine. Therefore, it can be used industrially.

1 Cylinder bore 2 Crank arm 6 Bottom plate 8 Exhaust pipe 10 Deep bottom 11 Shallow bottom 12 Step 13 Oil reservoir 14 Strainer 15 Oil drop passage
16 Oil return part 17 Heat pipe as an example of a heat conductor 17a Heat receiving part 17b Heat radiation part 17c Horizontal part 17d Inclined part 18 Fin 23 Baffle plate 24 Suspension piece

Claims (3)

An engine comprising an oil pan that stores oil, a strainer that sucks up oil from the bottom of the oil pan, and an oil return section that allows recirculated oil heated through the engine to flow into the oil pan, the engine comprising:
A heat conductor having a heat receiving part located above and a heat radiating part located below is disposed in the oil pan, the heat receiving part is in contact with the oil flowing down from the oil return part, and the heat radiating part is connected to the strainer. placed so as to be in contact with the oil being sucked in,
engine. The heat conductor is a heat pipe, and the heat pipe has a horizontal portion and an inclined portion extending from one end of the horizontal portion toward the bottom of the oil pan, the horizontal portion serving as the heat receiving portion and an end of the inclined portion serving as the heat dissipating portion.
2. An engine as claimed in claim 1. A portion of the heat conductor is connected to a baffle plate disposed inside the oil pan.
An engine as claimed in claim 1 or 2.

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