JP3052721B2 - Cylinder block for water-cooled internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in directing the flow of cooling water in a cylinder block of a water-cooled internal combustion engine.

[0002]

2. Description of the Related Art As a conventional cylinder block of a water-cooled internal combustion engine, for example, there is a cylinder block as shown in FIGS. 17, 18 and 19. The cylinder block 1 is formed by joining adjacent cylinder walls 2 to each other. A joint recess 6 sandwiched between the adjacent cylinder walls 2 and recessed in a concave shape
This is a so-called Siamese type in which the cylinder walls 2 are brought as close as possible to reduce the overall length of the engine.

[0003] Cooling water sent from a water pump flows in through an inlet 5 provided at the front end of the water jacket 3 and flows around each cylinder wall 22 as shown by the arrow in the figure. The heat is discharged from an outlet 9 provided in the section, and the heat of each cylinder wall 2 is taken away.

[0004]

However, such a conventional Siamese cylinder block 1 has a joint recess 6 which is sandwiched between adjacent cylinder walls 2 and is recessed. Therefore, a stagnation occurs in which the flow rate of the cooling water is significantly reduced at a portion of the water jacket 3 facing the joint concave portion 6.

FIGS. 20A and 20B show simulation data obtained by analyzing the flow rate and the heat transfer coefficient of the cooling water in the water jacket 3, respectively. However, it can be seen that heat radiation from the joint recess 6 to the cooling water is deteriorated. As a result, the temperature of the joint portion 7 of the adjacent cylinder wall 2 becomes higher than other portions of the cylinder wall 2, which may cause knocking or deform the cylinder bore.

[0006] Conventionally as this countermeasure, providing greatly narrow structure of the cylinder block 1 a passage width L ₂ of the water jacket 3 on its way, there is increasing the flow velocity of the cooling water flowing along the joining recess (JP-A 4-136461
Publication No.).

However, in this case, there is a problem that the water passage resistance increases due to a sudden change in the flow path cross-sectional area of the water jacket 3 and the drive loss of the water pump increases.

In addition, since the thickness of the core forming the water jacket 3 during casting of the cylinder block 1 is locally reduced, the core may be damaged by circumferential bending stress generated in the core. However, there is a problem that productivity is deteriorated.

An object of the present invention is to improve the cooling performance of a Siamese type cylinder block by focusing on the above problems.

[0010]

According to the first aspect of the present invention,
Cylinder walls adjacent in the cylinder row direction are joined to each other,
In a cylinder block of a water-cooled internal combustion engine, which has a joining concave portion which is sandwiched between adjacent cylinder walls and is concavely recessed, and a water jacket wall defining a water jacket through which cooling water circulates is provided outside these cylinder walls. A guide rib disposed substantially laterally of the center axis of the cylinder in the water jacket, the guide rib having its upstream end disposed substantially at the center in the vertical direction of the water jacket, and having the downstream end downstream from its upstream end. The water jacket has a shape that continuously expands in the vertical direction toward the end.

According to a second aspect of the present invention, in the first aspect of the invention, the guide rib is projected in a V shape toward the upstream side of the water jacket.

According to a third aspect of the present invention, in the first aspect of the present invention, the guide rib projects in a semicircular shape toward the upstream side of the water jacket.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the guide rib is raised from the water jacket wall toward the cylinder wall, and a gap is provided between the guide rib and the cylinder wall. Form.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, a notch for flowing cooling water is formed at a substantially central portion in the vertical direction of the guide rib.

[0015]

According to the first aspect of the present invention, a guide rib is provided substantially laterally of the center axis of the cylinder in the water jacket, and the upstream end of the guide rib is disposed substantially at the center of the water jacket in the vertical direction. At the same time, the cooling water flowing through the water jacket generates a vortex swirling facing the joint recess by forming a shape that continuously expands in the vertical direction of the water jacket from its upstream end to the downstream end. Thus, the flow velocity of the cooling water flowing along the joint recess can be increased.

In this way, by increasing the flow rate of the cooling water flowing along the joint recess, heat radiation from the joint recess to the cooling water is promoted, and the temperature distribution of the cylinder wall can be made uniform. As a result, while preventing knocking, suppressing deformation of the cylinder bore, making the piston gap uniform, reducing piston friction,
Oil consumption can be reduced.

According to a second aspect of the present invention, a pair of eddy currents swirling in a cooling water flowing through the water jacket so as to face the joint recess and face each other by the guide rib projecting in a V-shape toward the upstream side of the water jacket. And the flow rate of the cooling water flowing along the joint recess can be increased.

According to a third aspect of the present invention, a pair of guide ribs projecting in a semi-circular shape toward the upstream side of the water jacket are provided so as to face the cooling water flowing through the water jacket so as to face the joint concave portion and to pivotally oppose each other. A vortex is generated, and the flow velocity of the cooling water flowing along the joint concave portion can be increased.

According to the fourth aspect of the present invention, by forming a gap between the guide rib and the cylinder wall, a portion of the cylinder wall facing the guide rib during casting of the cylinder block is prevented from being excessively cooled, thereby improving productivity. Can be enhanced.

According to the fifth aspect of the present invention, since the cooling water flowing through the water jacket flows through the notch opened substantially at the center in the vertical direction of the guide rib, the vortex swirling facing the joint recess through the guide rib. The change in the flow path cross-sectional area of the water jacket can be reduced without impairing the action that occurs, and the flow resistance of the guide rib applied to the flow of the cooling water can be reduced.

[0021]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 2, the cylinder block 1 has four cylinder walls 2 arranged in series. The cylinder block 1 is of a so-called Siamese type in which adjacent cylinder walls 2 are joined to each other, and the cylinder walls 2 are made as close as possible to reduce the overall engine length. In the figure, reference numeral 8 denotes an oil drop hole.

The cylinder block 1 is provided with a water jacket 3 for circulating cooling water around each cylinder wall 2. The cylinder block 1 has a water jacket wall 4 defining a water jacket 3 with each cylinder wall 2.

The water jacket wall 4 is curved substantially along each cylinder wall 2 and has an inlet 5 at its front end and an outlet 9 at its rear end. Cooling water sent from the water pump flows into the water jacket 3 from the inlet 5, flows in the cylinder row direction (rearward) in the water jacket 3, is discharged from the outlet 9, and circulates through a radiator (not shown) or the like. ing.

The Siamese type cylinder block 1
Each of the adjacent cylinder walls 2 has a joining concave portion 6 which is concavely facing the water jacket 3.

As shown in FIG. 3, the guide ribs 10 for generating a pair of swirls which swirl toward the joint recesses 6 are formed in the cooling water flowing through the water jacket 3 as shown in FIG. It is provided substantially at the side of the central axis.

The guide rib 10 protrudes in a V-shape toward the upstream side of the water jacket 3.
Upstream end 11 arranged at the center in the vertical direction of
And two downstream ends 12 a and 13 from the upstream end 11.
It has an upper side portion 12 and a lower side portion 13 inclined toward a.

As shown in FIG. 4, the guide rib 10 is formed integrally between the cylinder wall 2 and the water jacket wall 4.

The operation will be described below.

The cooling water flowing into the water jacket 3 from the inlet 5 flows in the direction of the cylinders in the water jacket 3 and is discharged from the outlet 9 while absorbing the heat of the cylinder walls 2.

Since the V-shaped guide rib 10 is provided upstream of the joint recess 6 of the water jacket 3, the cooling water flowing through the water jacket 3, as shown by arrows in FIGS. A pair of vortices is generated which face the joint recess 6 and turn opposite to each other.

That is, the cooling water flowing through the water jacket 3 is directed upward along the upper side 12 of the guide rib 10 and then hits the upper wall 15 of the water jacket so as to descend along the joint recess 6 while being guided by the guide rib 10. After being directed downward along the lower side 13 of the 10, it hits the lower wall 16 of the water jacket and rises along the joint recess 6. The flows of the cooling water diverted through the guide ribs 10 as described above come into contact with each other at the central portion of the joint recess 6 and flow backward toward the rear of the guide ribs 10, thereby generating two vortices.

FIG. 5A shows simulation data obtained by analyzing the flow rate of the cooling water flowing through the water jacket 3. The cooling water flowing along the joint recess 6 is formed by the vortex of the cooling water generated by the guide ribs 10. It can be seen that the flow rate is increased.

FIG. 5B shows simulation data obtained by analyzing the heat transfer coefficient in the water jacket 3. It can be seen that the guide rib 10 promotes heat radiation from the joint recess 6 to the cooling water. By increasing the amount of heat radiated from the joint concave portion 6 to the cooling water, the temperature of the joint portion 7 of the adjacent cylinder wall 2 is suppressed from becoming higher than other portions of the cylinder wall 2, and the temperature distribution of the cylinder wall 2 is reduced By making it uniform, the occurrence of knocking can be suppressed, the deformation of the cylinder wall 2 can be suppressed, the piston gap can be made uniform, friction can be reduced, and oil consumption can be reduced.

FIGS. 6A and 6B show simulation data obtained by analyzing the flow velocity and the heat transfer coefficient when the guide rib 10 is made smaller. Both the flow rate and the heat transfer coefficient tend to decrease.

Further, since the cylinder block 1 is not to narrow large passage width L ₁ of the water jacket 3 as the conventional device in the middle, along with suppressing the flow resistance, the water jacket during casting of the cylinder block 1 The thickness of the core forming 3 can be prevented from being locally reduced, a sufficient section modulus for the circumferential bending stress generated in the core can be secured, and the core can be prevented from being damaged. Increases productivity.

FIGS. 7A and 7B show the flow rate and the heat transfer coefficient of another embodiment in which the guide ribs 17 project in a semicircular shape toward the upstream side of the water jacket 3 as another embodiment. The simulation data analyzed respectively are shown. The vortex of the cooling water generated by the guide ribs 17 increases the flow velocity of the cooling water flowing along the joint recess 6 and promotes the heat radiation from the joint recess 6 to the cooling water. It is understood that it is.

On the other hand, FIGS. 8A and 8B show simulation data obtained by analyzing the flow velocity and the heat transfer coefficient of a structure in which the guide rib 18 is formed in a cylindrical shape unlike the present invention. Guide rib 18
In some cases, the vortex of the cooling water is not effectively generated,
The flow velocity of the cooling water flowing along the joining recess 6 cannot be increased,
It can be seen that the heat radiation from the joint recess 6 to the cooling water deteriorates. The structure in which a cylindrical object is interposed in the water jacket is disclosed in Japanese Utility Model Laid-Open No. 56-101442.

Next, in another embodiment shown in FIGS. 9 and 10, a V-shaped guide rib 20 is provided on the water jacket wall 4.
And a gap 21 is formed between the guide rib 20 and the cylinder wall 2. 2 and 3 are designated by the same reference numerals.

In this case, the portion of the cylinder wall 2 facing the guide rib 20 during casting is prevented from being excessively cooled, and the productivity is increased.

Next, in another embodiment shown in FIGS. 11 and 12, a casting sand hole 2 formed in a water jacket wall 4 is formed.
A V-shaped guide rib 27 is formed on a plug 26 for sealing 5. The parts corresponding to those in FIG. 4 are denoted by the same reference numerals.

In this case, when providing the guide ribs 27, it is not necessary to change the shape of the core for molding the water jacket 3. Further, by simplifying the shape of the core, the strength of the core can be increased.

Next, in another embodiment shown in FIGS. 13 and 14, a notch 31 through which cooling water flows is formed at the center of the guide rib 30 in the vertical direction. 1 and 3 are denoted by the same reference numerals.

The guide rib 30 has an upper side portion 32 and a lower side portion 33 which extend straight from the notch 31 toward the downstream side in a vertical direction. The guide rib 30 is integrally formed between the cylinder wall 2 and the water jacket wall 4.

In this case, the cooling water flowing through the water jacket 3 has a notch 31 opened at the center of the guide rib 30.
, The change in the flow path cross-sectional area of the water jacket 3 is reduced. That is, as shown in FIG. 15, channel width of the water jacket 3, whereas the A ₁ at the site where the guide rib 30 is not provided, the upper side portion 32 and the lower side at the site where the guide ribs 30 are provided Only the width of the part 33 is reduced, and at its upstream end A ₁ + A ₂ + A ₃ ,
Next A ₄ + A ₅ + A ₆ at its downstream end, approximately equal to A _1. Since the change in the flow path cross-sectional area of the water jacket 3 is small, the flow resistance of the guide rib 30 to the flow of the cooling water can be suppressed to a small value, the driving loss of the water pump is small, and the fuel consumption is reduced.

Further, as shown in FIG.
By forming the upper side portion 42 and the lower side portion 43 extending in the vertical direction with the 0 notch 41 interposed therebetween, the cooling water is formed along the upper side portion 42 and the lower side portion 43 as shown by arrows in the figure. The velocity component in the vertical direction becomes strong, and a strong vortex can be generated behind the guide rib 40, that is, in the vicinity of the joint concave portion 6.

[0047]

As described above, according to the first aspect of the present invention, the adjacent cylinder walls in the cylinder row direction are joined to each other, and the joint recesses are sandwiched between the adjacent cylinder walls and are concavely recessed. In a cylinder block of a water-cooled internal combustion engine, a water jacket wall defining a water jacket through which cooling water circulates is provided outside these cylinder walls.
A guide rib is provided substantially at the side of the cylinder center axis in the water jacket. The guide rib has its upstream end located substantially at the center in the vertical direction of the water jacket, and has its upstream end located downstream from its downstream end. Part, the shape of the water jacket extends continuously in the vertical direction, so that the flow rate of cooling water flowing along the joint recess is increased,
Heat radiation from the joint recess to the cooling water is promoted, and the temperature distribution on the cylinder wall can be made uniform. As a result, engine power is improved by preventing knocking,
The deformation of the cylinder bore is suppressed, the piston gap is made uniform, the friction of the piston is reduced, and the oil consumption can be suppressed.

According to a second aspect of the present invention, in the first aspect of the present invention, since the guide ribs are projected in a V-shape toward the upstream side of the water jacket, the guide ribs face cooling water flowing through the water jacket so as to face the joint recess. A pair of vortices swirling opposite to each other are generated, and the flow velocity of the cooling water flowing along the joint recess can be effectively increased.

According to a third aspect of the present invention, in the first aspect of the present invention, since the guide ribs are projected in a semicircular shape toward the upstream side of the water jacket, the guide ribs face the cooling recess flowing through the water jacket. As a result, a pair of swirls swirling opposite to each other are generated, and the flow velocity of the cooling water flowing along the joint recess can be effectively increased.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the guide rib is raised from the water jacket wall toward the cylinder wall, and a gap is provided between the guide rib and the cylinder wall. Due to the formation, the portion of the cylinder wall facing the guide ribs during casting of the cylinder block is prevented from being excessively cooled, so that the quality can be improved and the productivity can be increased.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, a notch for circulating cooling water is formed at a substantially central portion in a vertical direction of the guide rib. The change in the cross-sectional area of the flow path of the water jacket is reduced and the resistance of the guide ribs to the flow of the cooling water is reduced, without impairing the action of generating a vortex that swirls facing the joint recess through And
The drive loss of the water pump is small, and the fuel consumption is reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a cylinder block showing an embodiment of the present invention.

FIG. 2 is a sectional view of the cylinder block.

FIG. 3 is a sectional view of the cylinder block taken along line AA of FIG. 2;

FIG. 4 is a sectional view of the cylinder block taken along the line BB of FIG. 2;

FIG. 5 is a distribution diagram of a flow rate of a cooling water and a distribution diagram of a heat transfer coefficient in the water jacket.

FIG. 6 is a distribution diagram of a flow rate of cooling water and a distribution diagram of a heat transfer coefficient in a water jacket when a guide rib is miniaturized as another embodiment.

FIG. 7 is a distribution diagram of a flow rate of cooling water and a distribution diagram of a heat transfer coefficient in a water jacket when a guide rib is formed in a semicircular shape as still another embodiment.

FIG. 8 is a distribution diagram of a flow rate of cooling water and a distribution diagram of a heat transfer coefficient in a water jacket when a guide rib is formed in a cylindrical shape as a comparative example.

FIG. 9 is a sectional view of a cylinder block showing still another embodiment.

FIG. 10 is a sectional view of the cylinder block taken along line AA of FIG. 9;

FIG. 11 is a sectional view of the cylinder block taken along the line BB in FIG. 9;

FIG. 12 is a distribution diagram of a flow velocity of a cooling water and a distribution diagram of a heat transfer coefficient in the water jacket.

FIG. 13 is a perspective view of a cylinder block showing still another embodiment.

FIG. 14 is a sectional view of the same cylinder block.

FIG. 15 is a side view of a guide rib, a water jacket, and the like.

FIG. 16 is a side view of a guide rib, a water jacket, and the like showing still another embodiment.

FIG. 17 is a sectional view of a cylinder block showing a conventional example.

FIG. 18 is a cross-sectional view of the cylinder block along the line AA in FIG.

FIG. 19 is a sectional view of the cylinder block taken along line BB of FIG. 13;

FIG. 20 is a distribution diagram of a flow rate of cooling water and a distribution diagram of a heat transfer coefficient in the water jacket.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder wall 3 Water jacket 4 Water jacket wall 6 Joining recess 10 Guide rib 11 Upstream end 12a Downstream end 13a Downstream end 17 Guide rib 20 Guide rib 27 Guide rib 30 Guide rib 31 Notch 40 Guide rib 41 Notch

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-136461 (JP, A) JP-A-1-69162 (JP, U) JP-A-63-63553 (JP, U) JP-A-62 135842 (JP, U) Japanese Utility Model Showa 57-109223 (JP, U) Japanese Utility Model Showa 61-17444 (JP, U) Japanese Utility Model Showa 58-183943 (JP, U) (58) Field surveyed (Int. ⁷ , DB name) F02F 1/00-1/42 F01P 3/02

Claims (5)

(57) [Claims] 1. A water in which adjacent cylinder walls in the cylinder row direction are joined to each other, and have joint recesses which are sandwiched between adjacent cylinder walls and are recessed, and cooling water circulates outside these cylinder walls. In a cylinder block of a water-cooled internal combustion engine provided with a water jacket wall that defines a jacket, a guide rib disposed substantially laterally of a cylinder center axis in the water jacket is provided, and the guide rib has an upstream end that is vertically above and below the water jacket. A cylinder block for a water-cooled internal combustion engine, wherein the cylinder block is arranged at a substantially central portion in a direction and has a shape that continuously extends in a vertical direction of a water jacket from an upstream end to a downstream end thereof. 2. The cylinder block for a water-cooled internal combustion engine according to claim 1, wherein the guide ribs are projected in a V-shape toward the upstream side of the water jacket. 3. The cylinder block for a water-cooled internal combustion engine according to claim 1, wherein the guide ribs are projected in a semicircular shape toward the upstream side of the water jacket. 4. A guide rib is raised from a water jacket wall toward a cylinder wall to form a gap between the guide rib and the cylinder wall.
A cylinder block for a water-cooled internal combustion engine according to any one of the above. 5. A cylinder block for a water-cooled internal combustion engine according to claim 1, wherein a notch for circulating cooling water is formed at a substantially central portion in a vertical direction of the guide rib. .