JP2022120556A - Cylinder block of internal combustion engine - Google Patents

Abstract

To provide a cooling structure which enables pinpoint cooling only to portions needing cooling of cylinders to prevent excessive cooling and insufficient cooling.SOLUTION: A group of cylinder bores 5, a water jacket 6, and a water delivery passage 9 are formed on an upper surface of a cylinder block 1. The water delivery passage 9 extends long in a crankshaft axis direction at the intake side. A wall part 12 which partitions the water delivery passage 9 from the water jacket 6 is formed with groove-like discharge passages 13 which jet jet flow of a coolant to upper parts of cylinders 7. Pinpoint cooling is performed at an upper end part, located at the intake side, of each cylinder 7 and thus excessive temperature rise of the air-fuel mixture is inhibited to inhibit knocking. Since the entire cylinder block 1 is kept warm, deterioration of heat efficiency does not occur.SELECTED DRAWING: Figure 1

Description

The present invention relates to a cylinder block of an internal combustion engine.

An internal combustion engine has a cylinder block, and a water jacket for cooling is formed in the cylinder block so as to surround a group of cylinders. The problem here is that the degree of temperature rise in the cylinder differs depending on the location, and for this reason, simply flowing cooling water through the water jacket will result in insufficient cooling or overcooling.

Regarding this point, for example, as disclosed in Patent Document 1, it is possible to insert a rectifying spacer in the water jacket to control the flow of the cooling water mainly to the upper portion and the portion between the bores of the water jacket. It is done. It has also been proposed to change the depth of the water jacket so that it is shallower on the intake side and deeper on the exhaust side, or that it is basically shallower but deeper between the bores (so-called shallow jacketing). .

JP 2018-131963 A

In recent internal combustion engines, combustion is suppressed so that heat is not wasted. Therefore, even if the temperature of the cylinder head rises, the temperature of the cylinder block tends not to rise so much. For this reason, simply passing water through the water jacket often results in supercooling, so the flow of cooling water is controlled by arranging spacers or making the jacket shallower.

On the other hand, an internal combustion engine has a knocking phenomenon in which fuel ignites before ignition and an abnormal noise is generated. However, in the conventional technology, it is only possible to change the flow of the cooling water, and it is not possible to perform concentrated cooling. I can say

In addition, the use of spacers as rectifying means increases the number of parts, which not only increases the cost, but also increases the weight, which may lead to deterioration in fuel efficiency.

The present invention is made to improve such a situation.

The present invention relates to an improvement of a cylinder block, and this cylinder block is
"A water jacket is formed so as to surround a group of cylinders, and a long water supply passage is formed in the direction of the crank axis at a portion located on the intake side across the water jacket,
A discharge passage for ejecting cooling water from the water supply passage toward the upper end of each cylinder is formed in a wall sandwiched between the water supply passage and the water jacket.
It is configured.

In the present invention, the water supply passage can be formed in a tunnel-shaped space, but in consideration of ease of manufacture and water permeability to the water jacket of the cylinder head, it is formed in the form of a groove that opens upward. Therefore, a gasket-sealed system is preferred.

Also, the discharge passage may be a hole formed by drilling or the like, but preferably has the form of a groove (or slit) opening upward. Also, the discharge passage may be provided at only one location corresponding to one cylinder, or may be provided at a plurality of locations. It is also possible to change the number of discharge passages for each cylinder.

In the present invention, the part of the cylinder on the intake side can be cooled intensively. Therefore, it is possible to prevent excessive temperature rise of the intake air and contribute to suppression of knocking. In addition, by suppressing partial expansion of the cylinder and maintaining the roundness of the cylinder, the effect of improving fuel efficiency by reducing friction of the piston and the effect of suppressing oil consumption by suppressing blow-by gas can be expected.

1 is a plan view of an embodiment; FIG. (A) is a cross-sectional view taken along line IIA-IIA in FIG. 1, and (B) is an enlarged view of a main portion of (A). It is a top view of example of another.

Next, embodiments of the present invention will be described based on the drawings. In this embodiment, the terms front-rear and left-right are used to specify the direction, and the front-rear direction is the direction of the crank axis, and the left-right direction is the direction perpendicular to the crank axis and the cylinder axis. Regarding the front and rear, the side on which the timing chain is arranged is the front, and the side on which the transmission is arranged is the rear. The directions are clearly indicated in FIG.

(1) Structure of the first embodiment This embodiment is applied to a gasoline internal combustion engine for automobiles. The internal combustion engine consists of a cylinder block 1 and a cylinder head 3 (Fig. 2), and a front cover (timing chain cover) 4 that is overlapped and fixed to the side surfaces of the cylinder block 1 and the cylinder head 3 .

The internal combustion engine of the present invention has three cylinders, and three cylinder bores 5 are formed in the cylinder block 1 in the direction of the crank axis, and a loop-shaped water jacket 6 is formed surrounding the group of the cylinder bores 5. ing. Accordingly, three cylinders 7 are formed by the group of cylinder bores 5 and the water jacket 6 , and the adjacent cylinders 7 are integrated through the inter-bore portion 8 .

A water supply passage 9 extending long in the crank axial direction (long along the group of cylinders 7) is formed in a portion of the cylinder block 1 located on the intake side with the water jacket 6 interposed therebetween. The water supply passage 9 is in the form of a groove that opens upward and is closed with a gasket 2 to form a passage.

An inflow port 10 communicates with the front end of the water supply passage 9 . The inlet 10 is located below the upper surface of the cylinder block 1 and opens to the intake side. Cooling water is pressure-fed from a water pump (not shown) to the inlet 10 . Therefore, the water pump is fixed to the intake side of the cylinder block 1 . In addition, the water pump is an electric type.

Cooling water is sent from the water supply passage 9 toward a water jacket (not shown) formed in the cylinder head 3 . 1, the water supply passage 9 is communicated with a communication passage 11 for blowing cooling water to the water jacket of the cylinder head 3. As shown in FIG. The communicating passages 11 are formed by making holes in the gasket 2 , and two communicating passages 11 are formed corresponding to each cylinder 7 .

By forming the water supply passage 9 in the cylinder block 1 , the cylinder block 1 is formed with a wall portion 12 sandwiched between the water jacket 6 and the water supply passage 9 . Discharge passages 13 for ejecting cooling water toward the cylinders 7 across the water jacket 6 are formed in portions of the wall portion 12 positioned on the left and right outer sides of the center of each cylinder 7 (or cylinder bore 5) in a plan view. It is The discharge passage 13 may be formed when the cylinder block 1 is cast, or may be formed by milling.

The discharge passage 13 is formed in a groove shape (slit shape) such as a semicircular cross section or a square cross section which opens upward, and is closed with a gasket 2 to form a tunnel. The discharge passage 13 may be formed with a constant depth as indicated by the solid line, or may be formed so as to become deeper toward the water jacket 6 as indicated by the one-dot chain line. The depth of the discharge passage 13 can be set arbitrarily.

In this embodiment, the water jacket 6 is shallowly formed to a depth of about half the radius of the cylinder bore 5 . Also, the water jacket 6 may be formed to have a constant depth. You may let When making the water jacket 6 shallow on the side of the center line of the cylinder 7, it may be applied only to the intake side, or may be applied to both the intake side and the exhaust side.

(2) Summary of the first embodiment In this embodiment, the cooling water in the water supply passage 9 is sent from each communication passage 11 to the water jacket of the cylinder head 3, while it is discharged to the water jacket 6 of the cylinder block 1. Although it is sent from the passage 13 , since the discharge passage 13 is narrow and narrow, the cooling water forms a jet flow across the water jacket 6 and hits the upper end of the cylinder 7 . That is, the upper end of the cylinder 7 is pinpoint-cooled by the jet water flow.

As a result, it is possible to intensively cool the upper end portion of the intake side portion of the cylinder 7 and prevent the air-fuel mixture from excessively increasing in temperature during the intake stroke. As a result, knocking can be prevented or significantly suppressed. In addition, by preventing the cylinder 7 from partially expanding and ensuring the roundness of the cylinder 7, the friction of the piston (not shown) can be reduced to improve fuel efficiency, and blow-by gas can be suppressed. Oil consumption can be suppressed.

Furthermore, in the present embodiment, the cooling water hits only the upper end portion of each cylinder 7 on the side of the center and performs pinpoint cooling. is not cooled, and most of the other parts are kept warm. Therefore, it is possible to prevent the cylinder block 1 from being too cold and to effectively utilize the heat. As described above, in this embodiment, heat insulation and cooling of the cylinder block 1 can be achieved at the same time, thereby contributing to an improvement in fuel efficiency.

If the water jacket 6 is shallow at least on the intake side, the cooling water jetted from the discharge passage 13 can be prevented from diffusing downward, and a strong water flow can hit the upper end of the cylinder 7 .

In this embodiment, the cooling water jetted from each discharge passage 13 flows through the water jacket 6 from the intake side toward the exhaust side, and is discharged to the water jacket of the cylinder head 3 through a communication path (not shown). Therefore, the cooling water jetted toward the central cylinder 7 passes through the sides of the cylinders 7 at both front and rear ends toward the exhaust side. Therefore, if the depth of the water jacket 6 located at both front and rear ends is set deeper than the depth of the central cylinder 7 side portion, the flow of cooling water can be made smooth.

Since the temperature of the cylinder 7 also rises in the portion between the bores 8, the portion between the bores 8 can also be cooled intensively. As cooling means for the inter-bore portion 8 , the discharge passage 13 may be formed in the wall portion 12 as in the present embodiment, or jet water may be ejected from the water jacket of the cylinder head 3 .

(3). Other Embodiments In the second embodiment shown in FIG. Also, the discharge passage 13 is inclined with respect to the center line of the left-right longitudinal direction so as to face the end of the water jacket 6 . Therefore, the discharge passage 13 located on the side of the cylinder 7 located midway between the front and rear has a pair of forward and backward slanted passages in plan view, forming an inverted V shape in plan view. , the discharge passages 13 corresponding to the cylinders 7 at both front and rear ends are slanted in the same direction in a plan view. That is, the discharge passages 13 corresponding to the front and rear cylinders 7 are inclined forward in plan view, and the discharge passages 13 corresponding to the front and rear cylinders 7 are inclined rearward in plan view.

When one discharge passage 13 is provided corresponding to each cylinder 7, the discharge passage 13 corresponding to the cylinder 7 located in the middle is oriented right sideways, and the discharge passages 13 corresponding to the front and rear cylinders 7 are The discharge passages 13 corresponding to the cylinders 7 located on the front side incline forward in plan view, and the discharge passages 13 corresponding to the cylinders 7 located in the rear side incline backward in plan view. Let it be.

Although the embodiments of the present invention have been described above, the present invention can be embodied in various other ways. For example, the target internal combustion engine is not limited to a 3-cylinder engine, but can be applied to a 1-cylinder internal combustion engine or a multi-cylinder internal combustion engine other than a 3-cylinder internal combustion engine.

Moreover, the discharge passage may be formed so that the cross-sectional area becomes smaller toward the water jacket so that a stronger water flow is generated. Conversely, if some degree of diffusivity is desired, the cross-sectional area may increase toward the water jacket.

The present invention can be embodied in a cylinder block of an internal combustion engine. Therefore, it can be used industrially.

Reference Signs List 1 cylinder block 3 cylinder head 5 cylinder bore 6 water jacket 7 cylinder 8 portion between bores 9 water supply passage 12 wall portion 13 discharge passage

Claims (1)

A water jacket is formed so as to surround a group of cylinders, and a long water supply passage is formed in the crank axial direction at a portion located on the intake side across the water jacket,
A discharge passage for ejecting cooling water from the water supply passage toward the upper end of each cylinder is formed in a wall sandwiched between the water supply passage and the water jacket.
Cylinder block of an internal combustion engine.

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