JP2010229831A - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal combustion engine for enhancing an oil cooling effect while suppressing an increase in manufacturing cost. <P>SOLUTION: The internal combustion engine 1 includes a body B and a guide member 46. The body B includes a cylindrical cylinder, a valve chamber arranged on the upper side of the cylinder, a water jacket formed around the outer circumference of the cylinder to flow cooling water, a crank chamber arranged on the lower side of the cylinder, an oil return passage arranged adjacent to the water jacket to connect the valve chamber to the crank chamber, and an intermediate wall for partitioning the water jacket and the oil return passage. The guide member is arranged in the oil return passage to receive at least part of oil flowing down from the valve chamber, and provided to guide at least part of the oil toward the intermediate wall. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for cooling oil in an internal combustion engine.

A conventional internal combustion engine mainly includes a cylinder block, a cylinder head provided at the upper part of the cylinder block, an oil pan provided at the lower part of the cylinder block, and a head cover provided at the upper part of the cylinder head. ing. A valve chamber is formed in the cylinder head. A valve operating mechanism for intake and exhaust of the combustion chamber is disposed in the valve operating chamber. A crank chamber is formed by the cylinder block and the oil pan. Oil is stored in the oil pan.
In a conventional internal combustion engine, oil stored in an oil pan is supplied to a valve operating chamber by a hydraulic pump. The oil supplied to the valve operating chamber, after lubricating or cooling the valve operating mechanism, flows on the upper deck of the cylinder head and returns to the oil pan through the return oil passage provided in the cylinder head and the cylinder block. .

  The cylinder head and the cylinder block are provided with a water jacket formed so as to surround the outer periphery of the cylinder. Cooling water is supplied to the water jacket by a cooling water pump. By arranging the aforementioned return oil passage adjacent to this water jacket, the oil can be cooled by the water jacket (see, for example, Patent Document 1).

JP-A 61-160510

However, in the conventional structure, depending on the amount of oil flowing through the return oil passage and the flow state, the oil may return to the oil pan without contacting the inner wall on the water jacket side among the inner walls forming the return oil passage. In such a flow state, the cooling efficiency of the oil by the water jacket is lowered.
In order to reliably cool the oil, it is conceivable to separately provide an oil cooler. However, since the manufacturing cost is greatly increased, the installation of the oil cooler is not realistic.
The subject of this invention is providing the internal combustion engine which can heighten the cooling effect of oil, suppressing the increase in manufacturing cost.

The internal combustion engine according to the present invention includes a main body portion and a guide member. The main body is disposed in a cylindrical cylinder, a valve operating chamber disposed on the upper side of the cylinder, a water jacket formed on the outer peripheral portion of the cylinder so that cooling water flows, and a lower side of the cylinder. The crank chamber includes a return oil passage that is disposed adjacent to the water jacket and connects the valve chamber to the crank chamber, and an intermediate wall that partitions the water jacket and the return oil passage. The guide member is disposed in the return oil passage and is provided so as to guide at least a part of the oil toward the intermediate wall.
Here, the “main body portion” may be a member that can form a water jacket or a return oil passage, and may be an integral member as a whole or may be composed of a plurality of members. For example, the case where the main-body part is formed with the head cover, the cylinder head, the cylinder block, and the oil pan can be considered. Further, the guide member may be integrally formed with the main body portion or may be a separate member from the main body portion. Furthermore, the guide member itself may be integrally formed or may be composed of a plurality of members.

“Upper side” and “lower side” mean an upper side and a lower side when the internal combustion engine is mounted on a vehicle.
In this internal combustion engine, the oil flowing from the valve operating chamber is guided toward the side wall on the water jacket side by the guide member. Cooling efficiency can be increased.

  As described above, in this internal combustion engine, the oil cooling effect can be enhanced while suppressing an increase in manufacturing cost.

Cross section of internal combustion engine 1 (II cross section of FIG. 3) Top view of cylinder head 3 Top view of cylinder block 4 III-III sectional view of FIG. The perspective view of the guide member 46 and its periphery A plan view of the guide member 46 and its surroundings Perspective view of guide member 46 (A) Side view of guide member 46, (B) VIIB-VIIB sectional view of FIG. 6, (C) VIIC-VIIC sectional view of FIG. (A)-(C) The figure which shows the flow of oil The perspective view of the guide member 146 and its periphery The perspective view of the guide member 246 and its periphery The perspective view of the guide member 346 and its periphery (A) And (B) Sectional view of guide member 446, (C) Sectional view of guide member 546

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<Overall configuration of internal combustion engine>
The internal combustion engine 1 will be described with reference to FIGS. In the following description, a direction parallel to the rotation axis A of the crankshaft 17 is defined as an “axial direction”. Therefore, the direction perpendicular to the paper surface of FIG. 1 coincides with the axial direction, and the horizontal direction of FIGS. 2 and 3 coincides with the axial direction. In FIG. 1, the right side is defined as the “intake side” and the left side is defined as the “exhaust side” with respect to the left and right positions of the rotation axis A. The following “upper side” and “lower side” mean the upper side and the lower side when the internal combustion engine 1 is mounted on a vehicle.
As shown in FIG. 1, the internal combustion engine 1 mainly includes a head cover 2, a cylinder head 3, a cylinder block 4, an oil pan 5, and a valve mechanism 6.

As shown in FIGS. 1 and 2, the cylinder head 3 has an upper deck 32 disposed on the upper side of the cylinder block 4. A head cover 2 is fixed to the cylinder head 3, and a valve operating chamber 34 in which the valve operating mechanism 6 is disposed is formed by the cylinder head 3 and the head cover 2. The valve mechanism 6 is a mechanism for switching between intake and exhaust of a combustion chamber 15 (described later), and is disposed on the upper deck 32.
As shown in FIG. 1, a crank chamber 10 in which a crankshaft 17 is disposed is formed by the cylinder block 4 and the oil pan 5. The crank chamber 10 is disposed below the cylinder block 4. Oil is accumulated in the oil pan 5, and the crank chamber 10 is connected to a hydraulic pump 9. The hydraulic pump 9 is driven by utilizing the rotational motion of the crankshaft 17 and supplies oil stored in the oil pan 5 to the periphery of the valve mechanism 6. The oil that has flowed onto the upper deck 32 returns to the crank chamber 10 through a first return oil passage P1 to a third return oil passage P3 (described later).

As shown in FIG. 3, the cylinder block 4 has a cylindrical first cylinder 13a to a fourth cylinder 13d. The first cylinder 13a to the fourth cylinder 13d are arranged at an equal pitch in the axial direction. As shown in FIG. 1, pistons 14 are movably arranged inside the first cylinder 13a to the fourth cylinder 13d (only the third cylinder 13c is shown in FIG. 1). 14 is connected to a crankshaft 17 via a connecting rod 16. Four combustion chambers 15 are formed by the cylinder head 3, the first cylinder 13 a to the fourth cylinder 13 d, and the piston 14.
As shown in FIGS. 1 and 3, the water jacket W is formed in the cylinder head 3 and the cylinder block 4 so as to surround the outer peripheral portions of the first cylinder 13a to the fourth cylinder 13d. A cooling water pump 8 is connected to the water jacket W, and the cooling water supplied from the cooling water pump 8 flows through the water jacket W. The cooling water flowing out of the water jacket W is radiated by a heat exchanger such as a radiator (not shown) and then returns to the water jacket W again. With these configurations, the first cylinder 13a to the fourth cylinder 13d can be cooled.

The head cover 2, the cylinder head 3, the cylinder block 4, and the oil pan 5 form a valve body 34, a crank chamber 10, a water jacket W, and a first return oil path P1 to a third return oil path P3. Is configured.
<First to third return oil passages>
As shown in FIG. 3, in order to return the oil supplied to the valve operating chamber 34 to the crank chamber 10, the internal combustion engine 1 has four first return oil passages P <b> 1 that connect the valve operating chamber 34 to the crank chamber 10. A third return oil passage P3 is provided. As shown in FIG. 1, the first return oil passage P1 to the third return oil passage P3 are arranged adjacent to the water jacket W, and the oil flows in the first return oil passage P1 to the third return oil passage P3. Is cooled by the water jacket W. In FIG. 4, only the cylinder head 3 and the cylinder block 4 are shown, and other configurations are omitted.

Here, the first return oil path P1 to the third return oil path P3 will be described in detail.
Each of the first return oil passage P1 to the third return oil passage P3 includes a plurality of oil passages. Specifically, as shown in FIG. 2, the cylinder head 3 includes a first upper oil passage 33a, a second upper oil passage 33b (an example of a first oil passage), and a third upper oil passage 33c (first oil passage). Example) and a fourth upper oil passage 33d. The first upper oil passage 33 a to the fourth upper oil passage 33 d communicate with the valve operating chamber 34. The first upper oil passage 33a to the third upper oil passage 33c are disposed on the exhaust side, and the fourth upper oil passage 33d is disposed on the intake side. The upper surface of the upper deck 32 is inclined so as to descend from the vicinity of the center toward the intake side and the exhaust side, so that the oil on the upper deck 32 can easily flow into the first upper oil passage 33a to the fourth upper oil passage 33d.
On the other hand, as shown in FIGS. 1 to 3, the cylinder block 4 includes a first lower oil passage 43a, a second lower oil passage 43b (an example of a second oil passage), and a third lower oil passage 43d. Is formed. The first lower oil passage 43a, the second lower oil passage 43b, and the third lower oil passage 43d communicate with the crank chamber 10.

The first lower oil passage 43a is disposed on the exhaust side of the first cylinder 13a and the second cylinder 13b, and is disposed below the first upper oil passage 33a. The first upper oil passage 33a communicates with the first upper oil passage 33a, and a first return oil passage P1 is formed by the first upper oil passage 33a and the first lower oil passage 43a.
The second lower oil passage 43b is disposed on the exhaust side of the second cylinder 13b and the third cylinder 13c, and is disposed on the lower side of the third upper oil passage. The second lower oil passage 43b communicates with the second upper oil passage 33b and the third upper oil passage 33c. The second upper oil passage 33b, the third upper oil passage 33c, and the second lower oil passage 43b Two return oil paths P2 (an example of a return path) are formed.
Further, the third lower oil passage 43d is disposed on the intake side of the third cylinder 13c, and is disposed below the fourth upper oil passage 33d. Since the third lower oil passage 43d communicates with the fourth upper oil passage 33d, a third return oil passage P3 is formed by the fourth upper oil passage 33d and the third lower oil passage 43d.

As shown in FIG. 4, unlike the first return oil path P1 and the third return oil path P3, the second return oil path P2 has a shape in which a space in the middle is widened. Specifically, the second lower oil passage 43b has an enlarged portion 49a and a discharge portion 49b.
The enlarged portion 49a is an oil passage that has a larger cross-sectional area than the second upper oil passage 33b, the third upper oil passage 33c, and the discharge portion 49b (see FIGS. 3 and 4). Here, the channel cross-sectional area means an area in a cross section perpendicular to the direction in which the oil flows as a whole (that is, the vertical direction) in the second return oil passage P2.
As shown in FIGS. 1 and 3, the enlarged portion 49 a is disposed on the side (exhaust side) of the water jacket W. Specifically, the enlarged portion 49a is disposed adjacent to the water jacket W across the intermediate wall 41a. The intermediate wall 41a partitions the water jacket W and the second return oil passage P2. A plate-like bottom portion 42b extending in a substantially horizontal direction is provided in a portion where the flow path is narrowed from the enlarged portion 49a to the discharge portion 49b.

The discharge portion 49b is an oil passage having a smaller flow path cross-sectional area than the enlarged portion 49a, and is disposed below the third upper oil passage 33c. The flow passage cross-sectional area of the discharge part 49b is set larger than the second upper oil passage 33b and the third upper oil passage 33c. Since the upper half of the discharge part 49b is disposed on the side (exhaust side) of the water jacket W, oil cooling by the water jacket W can be expected in the upper half of the discharge part 49b.
<Guide members and fins>
As described above, the first return oil passage P1 to the third return oil passage P3 are disposed adjacent to the water jacket W in order to cool the oil.
However, depending on the amount and flow state of the oil, the oil may return to the crank chamber 10 without contacting the intermediate wall 41a, and the water jacket W may not be able to cool the oil effectively.

Therefore, as shown in FIGS. 3 to 5, in the internal combustion engine 1, the guide member 46 is disposed in the second return oil path P <b> 2 so that the oil flows along the intermediate wall 41 a on the water jacket W side. Further, four fins 48 are provided on the intermediate wall 41a. Here, the fin 48 and the guide member 46 will be described in detail.
(1) Fins As shown in FIGS. 4 to 6, the cylinder block 4 is provided with four fins 48 protruding from the intermediate wall 41 a of the water jacket W. The fins 48 are plate-like portions that are long in the vertical direction, and are disposed in the second lower oil passage 43b with an interval in the axial direction. The fin 48 protrudes from the intermediate wall 41a to the side opposite to the water jacket W. The fins 48 are disposed below the upper surface 4a of the cylinder block 4 (a divided surface between the cylinder head 3 and the cylinder block 4). In this embodiment, since the cylinder block 4 is integrally formed by casting, the fin 48 is integrally formed with the intermediate wall 41a. The heat transfer area of the second return oil passage P2 can be increased by the fins 48.

(2) Guide member As shown in FIGS. 4 and 5, a guide is provided to guide the oil flowing from the second upper oil passage 33 b and the third upper oil passage 33 c to the space around the intermediate wall 41 a and the fins 48. The member 46 is arrange | positioned in the 2nd return oil path P2. The guide member 46 is disposed so as to surround the fin 48 in the enlarged portion 49a of the second lower oil passage 43b, and the guide member 46 is disposed on the bottom portion 42b. The guide member 46 is fixed to the side wall of the bottom 42b or the second lower oil passage 43b with an adhesive or the like. The guide member 46 is an integrally formed resin member. As the material of the guide member 46, a resin having relatively high heat resistance is conceivable, and examples thereof include PA66 (66 nylon), PA6 (6 nylon), PBT (Polybutylene terephthalate), PET (Polyethylene terephthalate), and PP (polypropylene). It is done.

As shown in FIGS. 4 to 8C, the guide member 46 mainly includes a guide portion 46f that inclines so as to descend to the water jacket W side, and an opposing surface that extends downward from the guide portion 46f along the intermediate wall 41a. 46g.
As shown in FIG. 7 to FIG. 8C, the guide portion 46f removes at least part of the oil flowing from the second upper oil passage 33b and the third upper oil passage 33c on the water jacket W side (intermediate wall 41a side). It is arranged to guide you. Specifically, the guide part 46f has a plate-like inclined part 46c and a side wall part 46b.
The inclined portion 46c has a guide surface 46h that is inclined so as to descend toward the water jacket W side (intermediate wall 41a side). In the present embodiment, the guide surface 46h is a flat surface. The side wall portion 46b protrudes upward from the three edges of the inclined portion 46c so that the oil falling on the inclined portion 46c easily flows to the water jacket W side, and the water jacket W side of the inclined portion 46c. It is not provided at the edge. Unlike the guide surface 46h, the upper surface of the side wall portion 46b is substantially horizontal, and the upper surface of the side wall portion 46b is set at a position higher than the upper surface of the fin 48 (see FIGS. 8A to 8C). .

As shown in FIG. 6, the guide member 46 has a second lower oil passage 43b that overlaps at least a part of the second upper oil passage 33b and at least a part of the third upper oil passage 33c when viewed from above. Is placed inside. More specifically, the inclined portion 46c is provided under the second upper oil passage 33b and the third upper oil passage 33c so as to receive oil flowing from the second upper oil passage 33b and the third upper oil passage 33c. Is arranged. In the present embodiment, when viewed from the upper side, the second upper oil passage 33b and the third upper oil passage 33c are within the range of the guide portion 46f (the inclined portion 46c and the side wall portion 46b). Thereby, most of the oil flowing from the second upper oil passage 33b and the third upper oil passage 33c can be received by the guide portion 46f, and the oil is guided to the water jacket W side by the guide portion 46f.
As shown in FIGS. 5 and 6, the facing portion 46g includes a first facing portion 46a and two plate-like second facing portions 46d arranged on the sides of the first facing portion 46a. is doing. The first facing portion 46 a is disposed so as to surround the fin 48 and has a shape complementary to the fin 48. Specifically, the first facing portion 46a has four grooves 46e into which the fins 48 are inserted on the surface on the intermediate wall 41a side. The dimension (width) of the groove 46e in the axial direction is larger than the dimension (thickness) of the fin 48 in the axial direction, and a gap is secured between the first facing portion 46a and the fin 48. Further, a gap is also secured between the first facing portion 46a and the intermediate wall 41a. As a result, oil flows between the first facing portion 46a and the fin 48 or between the first facing portion 46a and the intermediate wall 41a.

The second facing portion 46d is a plate-like portion disposed so as to face the intermediate wall 41a, and is disposed on the side of the first facing portion 46a in the axial direction. A gap is also secured between the second facing portion 46d and the intermediate wall 41a.
Further, it can be said that the guide member 46 partitions a part of the second return oil passage P2 into two spaces. Specifically, a first space S1 is formed on the water jacket W side of the guide member 46, and a second space S2 (an example of an auxiliary flow path) is formed on the opposite side of the guide member 46 from the water jacket W. Has been.
The first space S1 is a space between the guide member 46 and the fin 48 (more specifically, a space between the facing portion 46g and the fin 48), and a space between the guide member 46 and the intermediate wall 41a ( More specifically, the space between the opposing portion 46g and the intermediate wall 41a), and the oil guided by the guide portion 46f flows downward in the first space S1. The second space S2 is a space formed on the opposite side of the guide member 46 from the water jacket W. For example, the oil that overflows from the guide portion 46f flows through the second space S2.

<Oil flow>
Here, the flow of oil will be described in detail.
As shown in FIG. 1, when the crankshaft 17 rotates, the hydraulic pump 9 pumps oil stored in the oil pan 5 to the upper part of the valve mechanism 6. The supplied oil lubricates or cools the sliding portion of the valve mechanism 6 and falls onto the upper deck 32 of the cylinder head 3 and flows into the first return oil path P1 to the third return oil path P3.
For example, in the case of the second return oil passage P2, as shown in FIGS. 9A and 9B, the oil flowing into the second upper oil passage 33b or the third upper oil passage 33c is transferred to the second lower oil passage 43b. It flows into the inside (in the enlarged portion 49a) and falls onto the guide portion 46f. At this time, since the guide surface 46h of the inclined portion 46c is inclined toward the water jacket W, the oil flows toward the intermediate wall 41a along the guide surface 46h, and between the first facing portion 46a and the fin 48. , And flows between the first facing portion 46a and the intermediate wall 41a and further between the second facing portion 46d and the intermediate wall 41a. The oil that has flowed between the guide member 46 and the intermediate wall 41a returns to the crank chamber 10 through the discharge portion 49b. Thus, the oil can be reliably brought into contact with the intermediate wall 41a and the fin 48 by the guide member 46, so that the oil cooling efficiency can be increased.

Further, when the amount of oil flowing through the second return oil passage P2 is large, the oil overflows from the side wall portion 46b as shown in FIG. Oil also flows through the two spaces S2. For this reason, even when the amount of oil is large, a part of the oil is reliably cooled by flowing through the first space S1, and the remaining oil is also reliably transferred to the crank chamber 10 by flowing through the second space S2. Return.
<Features>
(1)
As described above, in the internal combustion engine 1, the oil flowing from the valve operating chamber 34 is guided toward the intermediate wall 41 a by the guide member 46. More specifically, since the guide member 46 has the guide surface 46h inclined so as to descend toward the water jacket W, the oil flow direction is likely to change toward the intermediate wall 41a. Becomes easy to contact the intermediate wall 41a. For this reason, the oil flowing into the second return oil passage P2 is easily cooled by the water jacket W, and the oil cooling efficiency can be enhanced with a simple configuration. That is, in the internal combustion engine 1, the oil cooling efficiency can be increased while suppressing an increase in manufacturing cost.

(2)
As shown in FIG. 7, since the guide member 46 has a facing part 46g extending downward from the guide part 46f along the intermediate wall 41a, the oil guided toward the intermediate wall 41a by the guide surface 46h. It becomes easy to flow along the intermediate wall 41a. It can be said that the guide member 46 has a function of adjusting the flow of oil. For this reason, even if the oil flow state in the second upper oil passage 33b or the third upper oil passage 33c changes, the oil can be reliably brought into contact with the intermediate wall 41a, and the oil cooling efficiency can be improved. it can.
(3)
As shown in FIG. 6, since the cylinder block 4 has four fins 48 protruding from the intermediate wall 41a toward the opposite side of the water jacket W, heat transfer between the water jacket W and the oil is performed. The area can be increased, and the oil cooling efficiency can be further increased. Since the fin 48 is arranged on the side where the oil is guided by the guide surface 46h, it can be expected that the cooling efficiency of the oil is greatly improved by the guide member 46 and the fin 48.

(4)
As shown in FIG. 6, the facing portion 46 g has a groove 46 e into which the fin 48 is inserted, and the width of the groove 46 e is larger than the thickness of the fin 48. That is, a gap is secured between the facing portion 46 g and the fin 48. For this reason, the oil easily flows along the fins 48, and heat transfer between the oil and the fins 48 is promoted.
(5)
As shown in FIGS. 1 and 5, since the fins 48 are arranged below the upper surface 4a of the cylinder block 4 (the divided surface of the cylinder head 3 and the cylinder block 4), the upper surface 4a of the cylinder block 4 is machined. The fins 48 need not be taken into consideration when machining, and damage to the fins 48 during machining and an increase in machining costs due to the fins 48 can be prevented. Further, the gap between the fin 48 and the cylinder head 3 can be used for an oil passage through which oil flows. For example, when the amount of oil is large, the fin 48 does not easily prevent the oil flow.

(6)
As shown in FIG. 6, since the guide member 46 is disposed in the second lower oil passage 43b so as to overlap the second upper oil passage 33b and the third upper oil passage 33c when viewed from the upper side, Most of the oil flowing through the second upper oil passage 33 b and the third upper oil passage 33 c falls on the guide member 46. For this reason, the oil can be reliably guided toward the intermediate wall 41a by the guide member 46.
(7)
Since the flow passage cross-sectional area of the enlarged portion 49a is larger than the flow passage cross-sectional areas of the first upper oil passage 33a and the second upper oil passage 33b, it is possible to ensure a large surface area of the intermediate wall 41a that forms the side surface of the enlarged portion 49a. The contact area between the oil and the intermediate wall 41a can be increased. Thereby, the cooling efficiency of oil can be improved.

Furthermore, when the channel cross-sectional area of the enlarged portion 49a is large, it becomes easy to secure a space for arranging the guide member 46, and the degree of freedom in design is increased.
(8)
Since the second space S2 is secured on the opposite side of the guide member 46 from the intermediate wall 41a, the second space S2 functions as a buffer according to the amount of oil flowing into the second return oil passage P2. Specifically, as shown in FIGS. 9A and 9B, when the amount of oil is small, most of the oil that has flowed into the second lower oil passage 43b is introduced into the first space S1 by the guide member 46. It flows in and comes into contact with the fin 48 and the intermediate wall 41a.
On the other hand, as shown in FIG. 9C, when the amount of oil is large, part of the oil that has flowed into the second lower oil passage 43b flows into the first space S1 by the guide member 46, and the first space S1. Then, the remaining oil that cannot flow completely overflows from the guide portion 46f, flows through the second space S2, and returns to the crank chamber 10 through the discharge portion 49b.

Thus, by securing the space (flow path) on the intermediate wall 41a side and the opposite side of the guide member 46, the cooling efficiency of the oil is prevented without hindering the function as the original oil path of the second return oil path P2. Can be increased. In particular, by adopting such a configuration, stable oil cooling efficiency can be realized regardless of the amount of oil.
<Other embodiments>
The specific configuration of the present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the scope of the invention.
In addition, about the structure which has the substantially same function as the above-mentioned structure, the same code | symbol is attached | subjected and the detailed description is abbreviate | omitted.
(A)
The shape and quantity of the fins 48 are not limited to the above-described embodiment. For example, if the heat transfer area increases, the fins 48 may have other shapes. Further, it is sufficient that at least one fin 48 is provided in the second lower oil passage 43b, and there is a case where the fin 48 is not provided at all. When the fin 48 is not provided, the above-described guide member 46 may be used.

In this case, for example, a guide member 146 shown in FIG. 10 can be considered as the guide member. The guide member 146 includes a guide portion 46f and a flat plate-like facing portion 146g disposed so as to face the intermediate wall 41a. A first space S1 is formed between the facing portion 146g and the intermediate wall 41a. Since the fin 48 is not provided, the guide member 146 does not have the above-described groove 46e.
Further, even when the fin 48 is not provided at all, the above-described guide member 46 may be disposed in the second lower oil passage 43b. In this case, a large cross-sectional area of the flow path between the intermediate wall 41a and the guide member 46 can be secured, and a margin can be given to the discharge capacity of the second return oil passage P2 while ensuring the cooling efficiency of the oil.
Furthermore, it is conceivable that the guide member 46 does not have the side wall portion 46b, or does not have the second facing portion 46d, or does not have the facing portion 46g. That is, as the simplest guide member, a guide member 246 as shown in FIG. 11 can be considered. The guide member 246 is fixed to the side wall of the second lower oil passage 43b, for example.

(B)
The guide member 46 may be formed integrally with the cylinder block 4. For example, as shown in FIG. 12, a guide member 346 having substantially the same shape as the guide member 146 may be integrally formed with the cylinder block 4. The guide member 346 has an inclined portion 346c inclined toward the water jacket W side, and an opposing portion 346g extending downward from the inclined portion 346c along the intermediate wall 41a. Even with such a configuration, the oil cooling efficiency can be increased as in the above-described embodiment.
Further, the guide member 46 may not be fixed to the cylinder block 4, and the guide member 46 may simply be placed on the bottom portion 42b.
(C)
The guide surface 46h does not have to be a flat surface, and as long as it is inclined downward toward the intermediate wall 41a, as shown in FIGS. 13A and 13B, the guide member in which the guide surface 446h is curved. 446 is also conceivable. Furthermore, as shown in FIG. 13C, a part of the guide surface 546h may include an inclined surface.

(D)
The guide member 46 should just be arrange | positioned in the lower side of at least one of the 2nd upper side oil path 33b and the 3rd upper side oil path 33c. Specifically, when viewed from above, the guide member 46 is placed in the second lower oil passage 43b so as to overlap with at least a part of the second upper oil passage 33b or at least a part of the third upper oil passage 33c. It only has to be arranged. If the oil is guided to the intermediate wall 41a side by the guide portion 46f, the oil cooling efficiency can be increased.
(E)
The configuration of the internal combustion engine is not limited to the above-described configuration. The present invention is applicable to any internal combustion engine having a water jacket W and a second return oil passage P2.

The main body B may be a member that forms the water jacket W or the second return oil passage P2, and may be partly or entirely formed integrally, or may be divided into finer members than those in the above-described embodiment. It may be.
(F)
The guide member 46 is made of resin, but may be formed of metal or other material.

  Since the internal combustion engine according to the present invention can improve the oil cooling efficiency, the present invention is useful in the field of internal combustion engines.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Head cover 3 Cylinder head 32 Upper deck 33a 1st upper oil path 33b 2nd upper oil path (an example of 1st oil path)
33c Third upper oil passage (an example of a first oil passage)
33d Fourth upper oil passage 4 Cylinder block 41a Intermediate wall 42b Bottom 43a First lower oil passage 43b Second lower oil passage (an example of the second oil passage)
43d Third lower oil passage 46 Guide member 46a First opposing portion 46b Side wall portion 46c Inclined portion 46d Second opposing portion 46e Groove 46f Guide portion 46g Opposing portion 46h Guide surface 49a Enlarged portion 49b Discharge portion 5 Oil pan 6 Valve mechanism P1 1st return oil path P2 2nd return oil path (an example of a return oil path)
P3 3rd return oil path S1 1st space S2 2nd space (an example of a flow path)

Claims (10)

A cylindrical cylinder, a valve operating chamber disposed on the upper side of the cylinder, a water jacket formed on the outer periphery of the cylinder and through which cooling water flows, and a crank disposed on the lower side of the cylinder A main body having a chamber, a return oil passage disposed adjacent to the water jacket and connecting the valve operating chamber to the crank chamber, and an intermediate wall separating the water jacket and the return oil passage;
A guide member disposed in the return oil passage and provided to guide at least a part of the oil toward the intermediate wall;
Internal combustion engine equipped with. The guide member has a guide surface that is inclined so as to descend toward the intermediate wall.
The internal combustion engine according to claim 1. The guide member includes a guide portion having the guide surface, and a facing portion that extends downward from the guide portion and is disposed to face the intermediate wall.
The internal combustion engine according to claim 2. The main body has at least one fin protruding from the intermediate wall to the opposite side of the water jacket.
The internal combustion engine according to any one of claims 1 to 3. The guide member has a groove into which the fin is inserted and whose size is larger than the thickness of the fin.
The internal combustion engine according to claim 4. The fin is disposed below the dividing surface of the main body,
The internal combustion engine according to claim 4 or 5. The return oil passage has a first oil passage that is disposed above the guide member and communicates with the valve operating chamber,
The guide member is disposed so as to overlap at least a part of the first oil passage when viewed from above.
The internal combustion engine according to any one of claims 1 to 6. The return oil passage has a second oil passage that communicates with the first oil passage and is disposed below the first oil passage.
The guide member is disposed in the second oil passage.
The internal combustion engine according to claim 7. The second oil passage communicates with the first oil passage and has an enlarged portion having a larger flow passage cross-sectional area than the first oil passage, and the enlarged portion is connected to the crank chamber and is disconnected from the enlarged portion. A discharge section having a small area,
The guide member is disposed in the enlarged portion.
The internal combustion engine according to claim 8. An auxiliary flow path is secured on the side opposite to the intermediate wall of the guide member,
The internal combustion engine according to any one of claims 1 to 9.

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