JP3133184B2 - Engine cooling structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for an engine in an automobile, and more particularly to a measure for improving the cooling efficiency of an engine having a water pump disposed at an end of a cylinder block.

[0002]

2. Description of the Related Art As a cooling structure for an engine in an automobile, a block-side water jacket formed around a cylinder liner of a cylinder block sends cooling water from one end of a cylinder row to one side of the cylinder row. Japanese Patent Laid-Open Publication No. Sho 63-193724 discloses a configuration in which a water jacket is caused to make a round along a cylinder row and cooling water is caused to flow into a water jacket on the cylinder head side through a communication hole therebetween. .

In this case, in order to reduce the size and weight and reduce the cost of the water pump, one end of a cylinder block in which the water pump is installed is also used as a pump casing, and an impeller is directly installed in a block-side water jacket. It is generally arranged at And, in order to bias the cooling water toward one side of the cylinder row, an introduction groove extending in the impeller rotation direction from an introduction port located at a lower portion of the rear wall is provided on the rear wall of the impeller so as to be biased toward the sending side. As shown in FIG. 11, when the impeller a rotates clockwise in FIG. 11, the cooling water flows as shown by the arrow in FIG. The cooling water returning to the side a flows into the head side water jacket d through the communication hole c located above the impeller a.

[0004]

However, in the above case, when the cooling water having returned to the impeller a after making a round around the block side water jacket b reaches the vicinity of the impeller a, the turbulent flow due to the rotation of the impeller a is reduced. Due to the interference, the flow of the cooling water to be directed to the communication hole c is pushed down, so that the flow rate of the cooling water flowing into the head-side water jacket d through the communication hole c tends to decrease. For this reason, there is a problem that a temperature variation occurs between the cylinders in the cylinder head, and in particular, the temperature of the combustion chamber becomes high in the cylinder located on the side of the impeller a at the end of the cylinder row.

To cope with this, it is conceivable to increase the capacity of the water pump by changing the water pump to a larger capacity. However, the water pump is generally used as a common part, and in that case, the layout of all models must be changed. In addition, there is also a problem of reliability of the gasket with respect to a water pressure that increases with an increase in capacity.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to prevent turbulence near the impeller from interfering with cooling water returning to the impeller after making a round around the water jacket on the block side. Accordingly, it is an object of the present invention to improve the cooling efficiency without using a large capacity water pump.

[0007]

In order to achieve the above object, according to the present invention, a projection is provided on the side of the impeller to which the cooling water returns, to cover the periphery of the impeller.

More specifically, according to the first aspect of the present invention, a block side water jacket formed around the cylinder liner of the cylinder block, and one end of the cylinder block inside the block side water jacket at one end of the cylinder block. A water pump that is disposed to face the cylinder liner at a position, and that causes the cooling water to flow radially outward by rotation of the impeller; and a water pump that is provided at the lower portion of the rear wall of the impeller of the water pump and has a block-side water jacket. An introduction port for introducing cooling water to the impeller, a communication hole provided at a position above the impeller, and a communication hole for communicating the block-side water jacket with the water jacket on the cylinder head side, and a rear wall of the impeller; Engine cooling structure with an inlet groove extending from the mouth in the impeller rotation direction It is.

A projection is provided so as to cover the periphery of the impeller from the end of the introduction groove to the front position in the impeller rotation direction of the introduction port. It is formed so that the interval with the cylinder liner in the section is narrowed.

According to a second aspect of the present invention, in the first aspect of the present invention, the projecting portion is formed so as to narrow the gap with the cylinder liner at the end of the cylinder row toward the lower end.

According to a third aspect of the present invention, in the second aspect of the present invention, the projecting portion is formed such that a space between the cylinder liner at the end of the cylinder row is increased at the upper and lower middle portions.

[0012]

According to the above construction, according to the first aspect of the present invention, when the impeller of the water pump is rotated, cooling water is sucked into the block side water jacket from the inlet at the lower portion of the rear wall of the impeller, and this cooling water is While flowing in the impeller rotation direction along the introduction groove from the introduction port, the impeller is caused to flow radially outward by the impeller. Therefore, the introduced cooling water is sent out to the cylinder row mainly toward the side where the introduction groove is provided. Also, the cooling water sent out by the impeller at the end of the introduction groove is sent out to the side opposite to the above-mentioned side of the cylinder row, that is, the side where the cooling water returns around the block side water jacket and returns. This attempts to disrupt the flow of the cooling water that has returned to the impeller after making a circuit. At this time, the cooling water is prevented from being sent radially outward from the periphery of the impeller from the end of the introduction groove to the impeller rotation direction front position of the introduction port from the end of the introduction groove,
The returned cooling water can be prevented from being turned downward by the interference of the turbulent flow. The returned cooling water tends to pass between the protruding portion and the end of the cylinder row, that is, between the cylinder liner on the impeller side. At this time, the cooling water flows upward along the protrusion because the protrusion is narrowed at the upper end with the cylinder liner. As a result, the returned cooling water flows into the head side water jacket through the communication hole located above the impeller, and the combustion chamber of the cylinder located at the end of the cylinder row is moved to the head side water jacket in the head side water jacket. Can be cooled.

According to the second aspect of the present invention, the cooling water flowing toward the lower portion of the impeller among the cooling water that has returned to the impeller after making a round around the block-side water jacket flows as it is and approaches the inlet. When the cooling water sucked into the water jacket from the introduction port is caught in the introduction groove and enters the introduction groove, and there is a possibility that the temperature of the cooling water circulating through the water jacket may be increased, Since the distance between the lower end and the cylinder liner on the impeller side is narrowed, the returned cooling water can be prevented from approaching the inlet.

According to the third aspect of the invention, the space between the upper and lower ends of the protruding portion and the cylinder liner located on the impeller side of the cooling water that has returned to the impeller after making a round around the block side water jacket is reduced. Due to this, when there is a possibility that it becomes difficult to circulate between the protrusion and the cylinder liner, the cooling water may have an increased interval between the upper and lower middle part of the protrusion and the cylinder liner. Accordingly, the gas flows through the portion where the space is widened, and flows along the outer peripheral surface of the cylinder liner. At this time, the cylinder liner can be cooled.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 10 show, for example, an in-line four-cylinder engine according to this embodiment. This engine includes a block-side water jacket 3 formed around a cylinder liner 2 of a cylinder block 1 and a cylinder block 1 shown in FIG. At the end on the side shown, the block-side water jacket 3
A water pump 5 disposed to face the cylinder liner 2 at the end of the inner cylinder row, and for causing the cooling water to flow radially outward by rotation of the impeller 4, and a back surface of the impeller 4 of the water pump 5. An inlet 6 provided at the lower part of the wall for introducing cooling water into the block-side water jacket 3, and a block-side water jacket 3 provided at a position above the impeller 4 to the water jacket 8 on the cylinder head 7 side. There is provided a communication hole 9 for communication, and an introduction groove 10 provided in the rear wall of the impeller 4 and extending from the introduction port 6 in the impeller rotation direction (clockwise direction in FIG. 1).

The impeller 4 is rotatably supported by a housing 5a fitted in a circular hole 11 formed at the end of the cylinder block 1 in a watertight manner as shown in FIGS. The V-belt wound around the crankshaft is driven to rotate. The inlet 6 is provided at the lower right portion of the housing 5a in FIG.
Introduced grooves 10 open toward the back surface of the impeller 4 are formed in arcuate portions extending over three thirds of the circumference. The distance between the housing 5a and the impeller 4, that is, the depth of the groove is, as shown in FIG.
20 mm at the beginning of the opening, that is, at the position of the inlet 6, and 20 mm, 18 mm, 16
mm, 11 mm, and 7 mm in order, and 3 mm at the end. The interval between the end portion and the position immediately before the inlet 6 in the radial direction of the impeller is 3 mm.

As shown in FIG. 1, a portion around the impeller 4 at the end of the cylinder block 1 is used to guide the flow direction of the cooling water flowing radially outward from the impeller 4. The guide groove 12 is provided with the introduction groove 10.
The first guide groove 12a extends from the position of the inlet 6 to a position approximately 135 ° in the direction of rotation of the impeller.
The second guide groove 12b extends from the end of the first guide groove 12a to a position approximately 135 ° in the impeller rotation direction. The first guide groove 12a receives the cooling water discharged from the impeller 4 on the left side in FIG. 1 of the cylinder row, and the second guide groove 12b is formed in an involute curve along the impeller rotation direction. Each of the guides 4 is guided toward the communication hole 9 located at a position above the reference numeral 4.

As a feature of the present invention, at a portion around the impeller 4 at the end of the cylinder block 1,
The protrusion 1 covering the periphery of the impeller 4 from the end of the introduction groove 10 to the front of the introduction port 6 in the impeller rotation direction.
3 are disposed substantially vertically. This protrusion 13
Water jacket 3 on the block side of cylinder block 1
2 to 8 are formed so as to bulge toward the cylinder liner 2 located on the impeller 4 side from the basic surface indicated by the imaginary line in FIGS. The intervals T1 and T2 are narrowed, and the intervals T2 and T
7 are formed so as to be expanded. Further, the protruding portion 13 has an upper end portion directed toward the communication hole 9 located above the impeller 4 and a lower end portion positioned at the inlet 6.
Are respectively extended downward along.

With the above configuration, in this embodiment, when the impeller 4 of the water pump 5 is rotated, the cooling water is sucked into the block-side water jacket 3 from the inlet 6 at the lower portion of the back wall of the impeller 4, The cooling water flows radially outward by the impeller 4 while flowing in the impeller rotation direction from the inlet 6 along the introduction groove 10. Therefore, the introduced cooling water is sent out to the cylinder row mainly toward the side where the introduction groove 10 is provided. Further, the cooling water sent out by the impeller 4 at the end of the introduction groove 10 is sent out to the side opposite to the above-mentioned side of the cylinder row, that is, the side where the cooling water goes around the block side water jacket 3 and returns. As a result, the flow of the cooling water that has returned to the impeller 4 after making a round is attempted to be disturbed. At this time, the cooling water is prevented from being sent radially outward from the periphery of the impeller 4 from the end of the introduction groove 10 to the front position in the impeller rotation direction of the introduction port 6 by the protrusion 13. Thus, as shown in FIG. 10, the returned cooling water can be prevented from changing its flow direction downward due to turbulent flow interference. The returned cooling water tends to pass between the protrusion 13 and the end of the cylinder row, that is, between the cylinder liner 2 on the impeller 4 side. At this time, the cooling water flows upward along the projection 13 because the interval T1 between the projection 13 and the cylinder liner 2 is narrowed at the upper end side. As a result, the returned cooling water flows into the head-side water jacket 8 through the communication hole 9 located above the impeller 4, and the combustion chamber of the cylinder located at the end of the cylinder row is moved to the head-side water jacket. Cooling can be performed in the water jacket 8.

In this way, the projection 13 prevents the water flow of the impeller 4 from interfering with the cooling water flowing toward the communication hole 9 near the impeller 4 after making a round around the block-side water jacket 3. It is possible to increase the flow rate of the cooling water flowing from the communication hole 9 to the head-side water jacket 8 without using a large-capacity water pump, thereby increasing the cooling efficiency of the impeller 4 side cylinder with respect to the combustion chamber. it can.

Of the cooling water that has returned to the impeller 4 after making a round around the water jacket 3 on the block side, the cooling water flowing toward the lower portion of the impeller 4 will approach the inlet 6 if it flows as it is. However, the cooling water sucked into the water jacket 3 from the inlet 6 gets caught in the flow groove 10 and gets into the introduction groove 10, which may increase the temperature of the cooling water circulating through the water jacket 3. . In this case, since the interval T2 between the protrusion 13 and the cylinder liner 2 on the side of the impeller 4 is narrowed at the lower end, the returned cooling water can be prevented from approaching the inlet 6. . As a result, it is possible to suppress a decrease in cooling efficiency due to the cooling water being sucked into the impeller 4 in the vicinity of the inlet 6 and sent out to the block-side water jacket 3 again.

On the other hand, the cooling water that has returned to the impeller 4 side by making a round around the block side water jacket 3 is
Due to the narrowing of the intervals T1 and T2 between the upper and lower ends of the cylinder 3 and the cylinder liner 2 located on the impeller 4 side, there is a possibility that it becomes difficult to flow between the protrusion 13 and the cylinder liner 2. There is. In this case, the cooling water is supplied to the space T3 between the upper and lower middle portions of the protrusion 13 and the cylinder liner 2.
-T7 is expanded, and flows through this portion and flows along the outer peripheral surface of the cylinder liner 2. At this time, the cylinder liner 2 can be cooled, and the cylinder liner on the impeller 4 side can be cooled. 2 can be prevented from lowering in cooling efficiency.

[0023]

As described above, according to the first aspect of the present invention, the projecting portion prevents the water flow of the impeller from interfering with the cooling water flowing toward the communication hole near the impeller after the block side water jacket has made one round. The flow rate of the cooling water flowing into the head-side water jacket through the communication hole can be increased without using a large-capacity water pump, thereby reducing the combustion of the impeller-side cylinder. It is possible to increase the cooling efficiency for the chamber and suppress the temperature of the combustion chamber from becoming higher than the combustion chambers of the other cylinders.

According to the second aspect of the present invention, it is possible to prevent the heated cooling water after flowing around the block side water jacket from flowing toward the inlet at the lower end side of the projecting portion. A decrease in cooling efficiency due to the cooling water being sucked into the impeller near the inlet and being sent out again to the block-side water jacket can be suppressed.

According to the third aspect of the present invention, when the cooling water that has returned to the impeller after making a round around the water jacket on the block side cools the cylinder liner on the impeller side, the cooling water is applied to the upper and lower intermediate portions of the projecting portion. And the cylinder liner can be easily passed through, so that a decrease in cooling efficiency for the cylinder liner can be suppressed.

[Brief description of the drawings]

FIG. 1 is a front view showing an end of an engine block in an engine according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part taken along line II-II of FIG.

FIG. 3 is an enlarged sectional view of a main part taken along line III-III of FIG. 1;

FIG. 4 is an enlarged sectional view of a main part taken along the line IV-IV in FIG. 1;

FIG. 5 is an enlarged sectional view of a main part taken along line VV of FIG. 1;

FIG. 6 is an enlarged sectional view of a main part taken along line VI-VI of FIG. 1;

FIG. 7 is an enlarged sectional view of a main part taken along line VII-VII of FIG. 1;

FIG. 8 is an enlarged sectional view of a main part taken along line VIII-VIII of FIG. 1;

FIG. 9 is a schematic view showing a depth dimension of each part of the introduction groove in the impeller rotation direction.

FIG. 10 is a perspective view schematically showing a flow of cooling water in the present embodiment.

FIG. 11 is a perspective view schematically showing a flow of cooling water in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder liner 3 Block side water jacket 4 Impeller 5 Water pump 6 Inlet 7 Cylinder head 8 Head side water jacket 9 Communication hole 10 Introducing groove 13 Projection

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyoshi Togita 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) References JP-A-58-93926 (JP, A) -57525 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F01P 5/10 F01P 3/02

Claims (3)

(57) [Claims] 1. A block-side water jacket formed around a cylinder liner of a cylinder block, and one end of the cylinder block facing a cylinder liner at an end of a cylinder row in the block-side water jacket. A water pump for causing the cooling water to flow radially outward by rotation of the impeller; and an inlet provided at the lower portion of the rear wall of the impeller of the water pump for introducing cooling water into the block-side water jacket. A communication hole that is provided above the impeller and communicates the block-side water jacket with the water jacket on the cylinder head side; and an introduction groove that is provided on the back wall of the impeller and extends in the impeller rotation direction from the introduction port. In the engine cooling structure provided with A protruding portion arranged to cover the periphery of the impeller over the front position in the impeller rotation direction, and the protruding portion is narrowed toward the upper end with the cylinder liner at the end of the cylinder row. An engine cooling structure characterized by being formed. 2. The cooling structure for an engine according to claim 1, wherein the projecting portion is formed so as to narrow a gap with a cylinder liner at an end of the cylinder row toward a lower end side. Engine cooling structure. 3. The engine cooling structure according to claim 2, wherein the projecting portion is formed so as to increase the interval between the cylinder liner at the end of the cylinder row at the upper and lower intermediate portions. Cooling structure.