JPH1077902A - Cylinder block of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a rise in temperature of lubricating oil of an oil gallery when the depth of a water jacket is shallowed. SOLUTION: Upward from an oil gallery 11 located at the lower deck part of a cylinder block 1, a cooling water passage 17 along the front and rear direction of an engine is formed side by side with the oil gallery 11. Lubricating oil of the oil gallery 11 is separately cooled with cooling water flowing in this cooling water passage 17. Lubricating oil which flows down from an oil return hole 23 and becomes a high temperature collides against the upper part wall 25 of the cooling water passage 17 stretching to the inside of an oil return chamber 24. Heat transfer from this high temperature lubricating oil to the oil gallery 11 is prevented by the cooling water passage 17 and lubricating oil flowing down to a crank case 26 receives a cooling action.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a cylinder block in a water-cooled internal combustion engine typified by an internal combustion engine for an automobile.

[0002]

2. Description of the Related Art Generally, a cylinder block, which is a main part of an internal combustion engine, is integrally cast using an aluminum alloy, cast iron, or the like. A plurality of cylinders are arranged along the engine front-rear direction. In addition, a skirt portion constituting an upper portion of the crankcase is integrally formed with the lower portion thereof. A plurality of bulkheads are provided so as to partition the inside of the skirt, and a main bearing for supporting the crankshaft is formed at the center of the bulkhead. In order to supply lubricating oil to each of the plurality of main bearings, a lubricating oil passage having a relatively large cross-sectional area along the engine front-rear direction, that is, an oil gallery is formed inside the lower deck along the lower end of the cylinder. ing. In this oil gallery, lubricating oil is introduced from an oil pump driven by a crankshaft via an oil filter, and is passed from an oil gallery formed in each bulkhead to each main bearing through an oil hole. The lubricating oil is distributed and supplied to the section.

Further, as a water-cooling type cooling device, a water jacket through which cooling water flows is formed so as to surround the outer periphery of the cylinder. That is, the water jacket wall is cast outside the cylinder wall, and the water jacket is formed between the two in a manner that is continuous in the front-rear direction of the engine.

The water jacket around the cylinder is generally formed between the upper deck portion and the lower deck portion of the cylinder block, that is, over substantially the entire axial length of the cylinder. In such a configuration, the oil gallery is close to the bottom of the water jacket, so that the lubricating oil flowing in the oil gallery is cooled by the cooling water.

On the other hand, in recent years, a configuration in which the depth of a water jacket around a cylinder is reduced to prevent excessive cooling of a cylinder wall is known (for example, Japanese Unexamined Utility Model Publication No. 1-173361). ).

That is, the bottom of the water jacket surrounding the outer periphery of the cylinder is provided at an intermediate height of the cylinder, and at the lower part of the cylinder, the outer peripheral surface of the cylinder wall is exposed outside without being surrounded by the water jacket. . Therefore, the temperature of the inner wall surface of the cylinder is maintained relatively high at the lower portion of the cylinder, friction loss due to piston sliding is reduced, and fuel efficiency can be improved.

[0007]

However, in the configuration in which the water jacket is made shallow and the outer peripheral surface of the cylinder wall below the cylinder is exposed to the outside as described above, the oil gallery formed on the lower deck portion and the water jacket bottom portion are formed. Are thermally separated from each other, and the cooling effect of the cooling water in the water jacket on the lubricating oil flowing in the oil gallery is extremely weak. Therefore, when the high load operation is continued, the temperature of the lubricating oil supplied to each part through the oil gallery may be excessively high.

An oil return passage for returning lubricating oil from the cylinder head side into the crankcase below the cylinder block is formed vertically through the cylinder block. In the cylinder block having the above configuration, when the oil return passage is arranged on the side of the cylinder block on the oil gallery side, heat is transmitted from the high-temperature return lubricating oil to the lubricating oil in the oil gallery, and from the oil gallery to each part. The temperature of the lubricating oil supplied to the tank is further increased.

[0009]

According to the present invention, a bottom portion of a water jacket formed so as to surround an outer periphery of a cylinder is located at an intermediate height of the cylinder, and an outer peripheral surface of a cylinder wall at a lower portion of the cylinder is exposed to the outside. Along with
In a cylinder block of an internal combustion engine in which an oil gallery is formed along the engine front-rear direction at a height position along the lower end of the cylinder, a cooling water passage is formed along the engine gallery along the oil gallery. Features.

That is, the water jacket around the cylinder is formed shallow, and the cylinder wall below the cylinder is kept at a relatively high temperature. Lubricating oil flowing in the oil gallery is separately cooled by cooling water flowing through a cooling water passage formed alongside the oil gallery.

According to a second aspect of the present invention, at least one of the vertically extending oil return passages for returning the lubricating oil from the cylinder head side to the crankcase is provided on a side having the oil gallery and the cooling water passage. I have.

According to a third aspect of the present invention, the cooling water passage is located above the oil gallery, and lubricating oil flowing down from the cylinder head through the oil return passage collides with the upper surface of the upper wall of the cooling water passage. like,
The upper wall is formed to protrude into the oil return passage.

In this configuration, the cooling water passage is located so as to separate the flow of the high-temperature lubricating oil and the oil gallery from the high-temperature lubricating oil returning from the cylinder head side to the crankcase. Is not transmitted to the lubricating oil in the oil gallery, and the temperature rise of the lubricating oil supplied from the oil gallery to each part is suppressed. At the same time, the high-temperature lubricating oil flowing down to the crankcase through the oil return passage is cooled by contacting the upper wall of the relatively low-temperature cooling water passage.

In the present invention, the upper surface of the upper wall is inclined so as to guide the lubricating oil to the inner wall surface of the crankcase.

[0015] As a result, the lubricating oil flowing down through the oil return passage flows along the inner wall surface of the crankcase, thereby suppressing collision with a rotating object such as a crankshaft or a connecting rod.

According to a fifth aspect of the present invention, the oil return passage is connected to an oil return hole formed in a straight line in the same cross section in the vertical direction from the top surface of the cylinder block, to a lower portion of the oil return hole, and to be connected to the oil return passage. It consists of an oil return chamber that extends beyond the opening of the hole,
An upper wall of the cooling water passage protrudes in the oil return chamber so as to intersect a center line of the oil return hole.

That is, the lubricating oil used on the cylinder head side flows through the oil return hole, and tends to linearly flow from the lower end opening into the oil return chamber. This lubricating oil collides with the upper surface of the upper wall of the cooling water passage,
It exchanges heat with the cooling water in the cooling water passage.

[0018]

According to the cylinder block of the internal combustion engine according to the present invention, the temperature rise of the lubricating oil flowing in the oil gallery can be suppressed even when the outer peripheral surface of the cylinder wall at the lower part of the cylinder is exposed to the outside. In particular, since the oil gallery and the cooling water passage are close to each other over a long range along the longitudinal direction of the engine, it is necessary to circulate a relatively small amount of cooling water to effectively cool the lubricating oil in the oil gallery. Can be.

According to the second, third and fifth aspects of the present invention, it is possible to prevent the lubricating oil in the oil gallery from rising in temperature due to the high-temperature lubricating oil flowing through the oil return passage, and at the same time, return to the crankcase. It is possible to cool the hot lubricating oil. Therefore, the oil return passage can be provided on the side of the cylinder gallery on the oil gallery side, and the degree of design freedom is improved.

According to the fourth aspect of the present invention, since the lubricating oil flowing down through the oil return passage is guided along the inner wall surface of the crankcase, a collision between the lubricating oil and the crankshaft or the like can be avoided.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 3 show an embodiment in which the present invention is configured as a cylinder block 1 of an in-line four-cylinder internal combustion engine.

This cylinder block 1 is made by casting each part integrally using cast iron, and has four cylinders 2 arranged in series along the engine front-rear direction.
Left and right skirts 4 are formed below the lower deck 3 along the lower end of each cylinder 2. Partition-shaped bulkheads 5 are formed at the positions between the cylinders and at the front and rear ends of the engine so as to partition the inside of the skirt portion 4 for each cylinder. A main bearing 6 for supporting a crankshaft (not shown) is formed at the center of the lower edge of the bulkhead 5. This embodiment is of a so-called deep skirt type as shown in FIGS. 2 and 3, and the skirt portion 4 extends below the rotation center of the crankshaft. An oil pan (not shown) is mounted on the oil pan mounting flange 10 at the lower end of the skirt 4.

As shown in FIG. 3, a water jacket wall 7 is formed outside a cylinder wall 9 constituting the cylinder 2, and a water jacket 8 surrounding the cylinder 2 is formed between the two. The water jacket 8 is continuous over four cylinders along the longitudinal direction of the engine. In this embodiment, the water jacket 8 is not provided between the cylinders, and the cylinder walls 9 of the adjacent cylinders are continuous with each other (see FIG. 2). The water jacket 8 has a shallower depth than the entire length of the cylinder 2 in the axial direction, and a bottom portion 8 a is provided at an intermediate height position of the cylinder 2. Accordingly, as shown in FIG. 3, at the lower part of the cylinder 2, the outer peripheral surface of the cylinder wall 9 is exposed to the outside without being covered by the water jacket 8.

On one side of the lower deck 3 located at the lower end of the cylinder 2, a lubricating oil passage, that is, an oil gallery 11 having a relatively large cross-sectional area along the longitudinal direction of the engine is provided.
Are formed. The oil gallery 11 is secondarily drilled after the cylinder block 1 is cast, and is formed linearly. As shown in FIG. 2, oil holes 12 reaching the main bearings 6 are connected to the oil gallery 11, respectively. Also, an oil filter mounting seat 13 provided on the side surface of the cylinder block 1.
The oil gallery 11 communicates with a central lubricating oil inlet 14 via a lubricating oil introduction passage 15. That is, the lubricating oil pressurized by the oil pump driven by the crankshaft (not shown) is supplied to the oil filter mounting seat 1.
After being filtered through an oil filter (not shown) mounted on the oil filter 3, the oil is introduced into the oil gallery 11, and is supplied from the oil gallery 11 to the main bearings 6 via oil holes 12.

Above the oil gallery 11, there is formed a bulging portion 16 that is linearly continuous in the front-rear direction of the engine, with one side of the lower deck portion 3 being thick in the axial direction of the cylinder 2. (See FIG. 1). The bulging portion 16 has a hollow tubular shape integrated with the lower portion of the cylinder wall 9, and has a cooling water passage 17 formed therein along the longitudinal direction of the engine. This cooling water passage 17 is formed by a core at the time of casting the cylinder block 1, and as shown in FIG.
Except for the front and rear end portions, it is substantially straight, and is formed along the upper side of the oil gallery 11 and in parallel with the oil gallery 11.

The cooling water passage 17 has a circular passage cross section having a diameter substantially equal to that of the oil gallery 11, as shown in FIGS. The cooling water passage 17 has a front end communicating with a cooling water introduction chamber 18 at the front end of the cylinder block 1, and a rear end connected to a cooling water discharge passage 19. The cooling water introduction chamber 18 communicates with a discharge port of a water pump (not shown), and the water jacket 8 and the cooling water passage 17 are communicated through the cooling water introduction chamber 18.
And the cylinder head side water jacket (not shown)
Cooling water is distributed to the workers. The upper end of the cooling water discharge passage 19 formed along the vertical direction of the cylinder block 1 communicates with a not-shown cylinder head side water jacket. Therefore, a part of the cooling water pumped by a water pump (not shown) is introduced into the cooling water passage 17 through the cooling water introduction chamber 18 and flows through the cooling water passage 17 to the rear of the engine to discharge the cooling water. The fluid flows through the passage 19 to the cylinder head side water jacket.

As shown in FIG. 2, on both sides of the cylinder block 1, oil return passages 21 and 22 for returning lubricating oil from the cylinder head (not shown) into the crankcase 26 are respectively formed along the vertical direction. It is formed. These oil return passages 21 and 22 are formed substantially at the center of the cylinder block 1 in the front-rear direction, that is, between the # 2 cylinder and the # 3 cylinder. As shown in FIG. 2, the oil return passage 21 provided on the side opposite to the oil gallery 11 has an upper end opened on the upper surface of the cylinder block 1, and a lower end provided with a communication port 21a.
6 communicates with the upper part.

Oil gallery 11 and cooling water passage 17
The other oil return passage 22 provided on the side having the upper portion has an upper oil return hole 23 and a lower oil return chamber 24. The oil return hole 23 is secondarily drilled, has an upper end opening on the upper surface of the cylinder block 1, and is formed in a straight line parallel to the cylinder 2. The oil return chamber 24 is formed by hollowing out the skirt portion 4 of the cylinder block 1 as shown in FIG. It is slightly spread. The oil gallery 11 and the cooling water passage 17 project into the oil return chamber 24. In other words, the upper wall 25 projects laterally so that the lubricating oil that has flowed downward from the lower end opening of the oil return hole 23 collides with the upper wall 25 that covers the upper part of the cooling water passage 17. , The center line of the oil return hole 23 intersects the upper wall 25. This is a relative positional relationship between the oil return passage 22 and the cooling water passage 17, and as described above, the cooling water passage 17 and the oil gallery 1
1 itself is formed linearly. In other words,
The oil return passage 22 is formed so as to bypass the cooling water passage 17 and the oil gallery 11 from above to the side. The upper surface 25a of the upper wall 25 against which the lubricating oil collides is inclined sideways so as to guide the colliding lubricating oil to the inner wall surface 27 of the crankcase.

In the configuration of the above embodiment, the cylinder 2
Since the water jacket 8 is not provided at the lower part of the cylinder 2 and the cylinder wall 9 at the lower part of the cylinder 2 is exposed, the cylinder wall 9 in this part is not excessively cooled, and the friction loss is reduced. The oil gallery 11 located away from the water jacket 8 is separately cooled by cooling water flowing through a cooling water passage 17 formed alongside the oil gallery 11. The above oil gallery 1
Since the cooling water passage 1 and the cooling water passage 17 are adjacent to each other over substantially the entire length of the cylinder block 1, the lubricating oil in the oil gallery 11 can be effectively used by flowing a relatively small amount of cooling water. Is cooled. Therefore, the lubricating oil supplied to the main bearing 6 and the like does not become excessively hot.

The lubricating oil used on the cylinder head side (not shown) flows down to the crankcase 26 through the oil return passages 21 and 22, but the high-temperature lubricating oil passes through the oil return passage 22 on the oil gallery 11 side. Collides with the upper wall 25 above the cooling water passage 17 as shown by an arrow in FIG. Therefore, the cooling water passage 17 is interposed between the oil gallery 11 and the upper wall 25 where the high-temperature lubricating oil contacts, and the high-temperature lubricating oil flowing through the oil return passage 22 The transfer of heat to the relatively cool lubricating oil is prevented. That is, the lubricating oil in the oil gallery 11 is not heated by the return lubricating oil from the cylinder head side. At the same time, the lubricating oil flowing down the oil return passage 22 is cooled by coming into contact with the upper wall 25 of the cooling water passage 17.

When the lubricating oil flowing through the oil return passage 22 tries to linearly fall downward from the lower end opening of the oil return hole 23, it collides with the upper surface 25a of the upper wall 25. And scatters to the side as shown by the arrow, and adheres to the inner wall surface 27 of the crankcase. Then, it flows down along the inner wall surface 27 of the crankcase. Therefore, the lubricating oil does not collide with the crankshaft, the connecting rod, and the like that rotate at high speed in the crankcase 26, and it is possible to avoid mixing of air into the lubricating oil and an increase in mechanical loss.

In the above-described embodiment, an example in which the present invention is applied to a series internal combustion engine has been described. However, the present invention can be similarly applied to, for example, a V-type internal combustion engine.

[Brief description of the drawings]

FIG. 1 is a side view showing one embodiment of a cylinder block according to the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG. 1;

FIG. 3 is a sectional view taken along the line BB of FIG. 1;

FIG. 4 is an explanatory diagram showing a flow of lubricating oil through an oil return passage.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cylinder block 8 ... Water jacket 11 ... Oil gallery 17 ... Cooling water passage 22 ... Oil return passage 23 ... Oil return hole 24 ... Oil return chamber 25 ... Upper wall

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location F02F 1/00 F02F 1/00 N

Claims (5)

[Claims] 1. A bottom portion of a water jacket formed so as to surround the outer periphery of a cylinder is located at an intermediate height position of the cylinder, an outer peripheral surface of a cylinder wall at a lower portion of the cylinder is exposed to the outside, and In a cylinder block of an internal combustion engine in which an oil gallery is formed at a height along the engine longitudinal direction, a cooling water passage is formed along the oil gallery along the engine longitudinal direction in the cylinder block of the internal combustion engine. Engine cylinder block. 2. An oil return passage for returning lubricating oil from a cylinder head side to a crankcase in a vertical direction is provided on a side having the oil gallery and the cooling water passage. The cylinder block for an internal combustion engine according to claim 1, wherein 3. The cooling water passage is located above the oil gallery, and the upper wall is formed such that lubricating oil flowing down from the cylinder head through the oil return passage collides with the upper surface of the upper wall of the cooling water passage. 3. A cylinder block for an internal combustion engine according to claim 2, wherein said cylinder block protrudes into said oil return passage. 4. The cylinder block according to claim 3, wherein an upper surface of the upper wall is inclined so as to guide lubricating oil to an inner wall surface of the crankcase. 5. The oil return passage, wherein the oil return passage is formed in a straight line with the same cross section in the vertical direction from the top surface of the cylinder block, and is connected to a lower portion of the oil return hole. 5. An oil return chamber which is also widened, wherein an upper wall of the cooling water passage projects in the oil return chamber so as to intersect a center line of the oil return hole. A cylinder block for an internal combustion engine according to claim 1.