JP6712947B2 - Water cooling engine cooling structure - Google Patents

Description

The present invention relates to a cooling structure applied to an industrial diesel engine or the like, and more specifically, to cooling a water-cooled engine including a plurality of cylinders arranged in a cylinder block and a water jacket formed around the plurality of cylinders. It is about structure.

As a cooling structure in a water-cooled engine, a water jacket is generally provided around a cylinder or a cylinder head, which is a heat generating point, and cooling water is circulated. In the case of a multi-cylinder engine having two or more cylinders such as an in-line 4-cylinder engine, cooling between adjacent cylinders, that is, cooling between bores is often necessary.

When there are two or more cylinders, it is preferable to arrange adjacent cylinders as close to each other as possible in order to make the engine length compact. However, the thermal load is most severe between the cylinders, which are also sources of heat, that is, between the bores. Therefore, conventionally, as disclosed in Patent Document 1, a means has been adopted in which a water hole is formed by punching a hole between the bores of the cylinder by post-processing.

By installing drill holes, cooling water is passed between the bores and the cooling performance is improved, but if the thermal load is higher, such as in high compression engines and large displacement engines, strengthening of inter-bore cooling is desired. .. Therefore, in the past, a means for further improving the cooling property has also been adopted, such as by using a core core, by clearly separating adjacent cylinders and providing a clear water jacket between the bores.

In the latter conventional technique, the cooling performance is improved, but the inter-bore distance is required for that amount, and as a result, the engine length tends to increase in size. The former conventional technique is advantageous in terms of engine length, but is inferior to the latter conventional technique in terms of cooling performance. As described above, the conventional cooling structure for a water-cooled engine has advantages and disadvantages in terms of suppressing an increase in engine length and improving cooling performance.

JP-A-2007-023824 JP, 2003-193836, A

An object of the present invention is to provide a cooling structure for a water-cooled engine, which is capable of achieving sufficient cooling between bores without increasing the length of the engine by further improving the structure and achieving both the miniaturization of the engine length and the cooling performance. Is in the point of providing.

The invention according to claim 1 is a cooling structure for a water-cooled engine,
A plurality of cylinders 2 arranged in a cylinder block 1,
A water jacket W formed around the plurality of cylinders 2;
The water jacket W has interbore channels 9 and 10 formed between adjacent ones of the barrel portions 4 forming the cylinder 2 in the cylinder block 1 .
Rib walls 21 extending in the axial direction of the cylinder 2 in the interbore channels 9 and 10 are formed so as to project from the outer peripheral wall 4A of the barrel portion 4 ,
The rib wall 21 is characterized in that it has a tapered shape whose width along the circumferential direction of the cylinder 2 becomes narrower as it approaches the cylinder head.

The invention according to claim 2 is the cooling structure for a water-cooled engine according to claim 1,
The rib wall 21 is provided at a portion opposite to the cylinder head side in the interbore passages 9 and 10 on a side opposite to the cylinder head side.

The invention according to claim 3 is the cooling structure for a water-cooled engine according to claim 1 or 2,
The taper angle θ of the rib wall 21 is set to 20±5 degrees.

The invention according to claim 4 is the cooling structure for a water-cooled engine according to any one of claims 1 to 3 ,
A damming wall 16 is formed to connect the opposite cylinder head side portions of the adjacent barrel parts 4 opposite to each other on the cylinder head side . 10 is formed,
It is characterized in that the width of the damming wall 16 along the circumferential direction of the cylinder 2 is formed in a tapered shape which becomes narrower toward the cylinder head side.

The invention according to claim 5 is the cooling structure for a water-cooled engine according to claim 4,
The taper angle γ of the damming wall 16 is set to 20±5 degrees.

The invention according to claim 6 is the cooling structure for a water-cooled engine according to claim 4 or 5, characterized in that the rib wall 21 is also formed so as to be raised from the damming wall 16 .

According to the present invention, the outer peripheral wall of the barrel portion forming the interbore channel is formed with a rib wall having a tapered shape whose width becomes narrower toward the cylinder head side. A guide action occurs in which the flowing cooling water is guided and guided to the cylinder head side by the left and right side surfaces of the rib wall. Therefore, in the flow path between the bores, the flow on the cylinder head side, which has severe thermal conditions, is promoted, and cooling can be performed more efficiently than in the conventional cooling structure.
As a result, by further devising the structure, it is possible to perform sufficient inter-bore cooling without increasing the engine length, and to provide a cooling structure for a water-cooled engine that achieves both a reduction in engine length and cooling performance. be able to.

Instead of the rib wall, an interbore channel is formed on the upper side of the damming wall connecting the lower parts of the adjacent barrels, and the damming wall is tapered so that the width becomes narrower toward the cylinder head side. Even when the configuration is adopted, the above-mentioned effects can be obtained similarly.

Top view of the cylinder section showing the cylinder block A line aa sectional view of the cylinder block shown in FIG. Bb line sectional view of the cylinder block shown in FIG. 2 is a sectional view taken along the line cc of the cylinder block shown in FIG. Shows the flow of cooling water in the water jacket, (a) when the guide walls are in opposite directions, (b) is when the guide walls are in the same direction

An embodiment of a cooling structure for a water-cooled engine according to the present invention will be described below as being applied to a vertical in-line 3-cylinder water-cooled diesel engine with reference to the drawings.

As shown in FIGS. 1 and 4, in this engine, a plurality of (three) cylinders 2 are arranged in series in a cylinder block 1, and a water jacket (cylinder jacket) W formed around the plurality of cylinders 2 is provided. It is equipped with a water-cooled engine. The water jacket W includes barrel portions (cylinder walls) 4, 4, 4 which are formed upright in a substantially tubular shape to form each cylinder 2 in the cylinder block 1, a cylinder outer frame portion 5 in the cylinder block 1, and a cylinder ceiling. It is an internal space for cooling water circulation formed between the wall 3 and the wall 3. A portion of the front side of the cylinder block 1 that extends to the left side is a fuel injection case portion 26.

1 and 4, the intake side of the cylinder block 1 is left, the exhaust side is right, the side with the cooling water inlet 6 to the water jacket W is the front, and the opposite side is the rear.
The water jacket W is a pair of main flow passages that are formed outside the cylinder 2 (barrel portion 4) in a state of extending in the cylinder arrangement direction, that is, an intake-side main flow passage 7 and an exhaust-side main flow passage 8, and a pair of main flow passages 7. , 8 connect the first and second inter-bore channels 9 and 10 formed between adjacent cylinders 2 (barrel portion 4) in a state of connecting them, and the main flow channels 7 and 8 start and end ends It is configured to have front and rear end channels wf and wr.

As shown in FIGS. 1 and 4, in the cylinder ceiling wall 3 to which the cylinder head (not shown) is connected to its upper surface 3A via a gasket (not shown), a bolt insertion hole 3a, a communication hole 3b, a drill hole, and a hole are formed. The hole 3c is formed. The bolt insertion holes 3 a are holes through which bolts for connecting the cylinder block 1 and the cylinder head (not shown) are inserted, and are formed at a plurality of positions (14 positions) around each cylinder 2. The communication hole 3b is a relatively large passage for allowing the cooling water to flow from the water jacket W to the water jacket (cylinder head jacket: not shown) of the cylinder head, and is in a state of communicating with either of the main flow paths 7 and 8. It is formed in plural (12 places).

The drill holes 3c are formed at a total of four positions at the front and rear ends of the cylinder ceiling wall 3 so as to communicate with the front end channel wf and the rear end channel wr of the water jacket W, respectively. In addition, between the adjacent cylinders 2 and 2 of the cylinder ceiling wall 3, in a state of communicating with the first inter-bore channel 9 and the second inter-bore channel 10, respectively, an oblique hole extending from the upper left to the lower right is formed. , Each of which is formed at one place.

3 and 4, the hole provided at the front end of the cylinder block 1 so as to face the front end flow path wf is an auxiliary device such as a thermostat (not shown) or a sensor (not shown) for measuring the cooling water temperature. It may be a mounting hole 25 for mounting.

Now, the cooling water sent from the cooling water inlet 6 to the water jacket W by the water pump (not shown) is first separated into the left and right from the front end flow passage wf, and goes back through the intake side main flow passage 7 and the exhaust side main flow passage 8. To the first and second inter-bore channels 9, 10 on the way. Then, the cooling water flows backward as well as upward in the water jacket W, flows into the cylinder head jacket (not shown) through the plurality of communication holes 3b and the plurality of perforation holes 3c, and flows into the cylinder head jacket (not shown). It flows toward the cooling water outlet (not shown).

As shown in FIG. 4 and FIG. 5( a ), in the cylinder block 1, guide walls h (11 to 14) capable of guiding the cooling water flowing through the main flow paths 7 and 8 to the interbore flow paths 9 and 10. Are formed at four locations. Specifically, the first guide wall 11 protruding from the front side portion of the front and rear intermediate second barrel portion 4 into the intake side main flow passage 7 and the first guide wall 11 protruding from the rear side portion of the front side first barrel portion 4 into the exhaust side main flow passage 8 2 guide walls 12, a third guide wall 13 protruding from the rear part of the front and rear intermediate second barrel part 4 into the intake side main flow path 7, and a front part of the rear side third barrel part 4 to the exhaust side main flow path 8. The protruding fourth guide wall 14 constitutes a guide wall h.

The first guide wall 11 having an arc shape along the circumferential direction of the first cylinder 2 on the front side when viewed in the vertical direction allows the cooling water flowing from the front to the rear in the intake-side main flow path 7 near the first cylinder 2. , A guiding action for guiding the first inter-bore channel 9 to the right is exhibited. Flowing from left to right (from the intake side to the exhaust side) in the first inter-bore flow passage 9 by the second guide wall 12 having an arc shape along the circumferential direction of the second cylinder 2 in the front-rear direction in the vertical direction. A guiding action is exhibited in which the cooling water is guided obliquely rearward to the right and merges with the exhaust-side main flow path 8.

By the fourth guide wall 14 having an arcuate shape along the circumferential direction of the second cylinder 2 when viewed in the vertical direction, the cooling water flowing from the front to the rear in the exhaust side main flow path 8 near the second cylinder 2 is left. A guiding action of guiding the second inter-bore flow path 10 toward is exerted. Flowing from right to left (from exhaust side to intake side) in the second inter-bore flow passage 10 by the third guide wall 13 having an arcuate shape along the circumferential direction of the rear third cylinder 2 when viewed in the vertical direction. A guiding action is exhibited in which the cooling water is guided to the left rear obliquely and merges with the intake side main flow path 7.

As described above, the first guide wall 11 and the third guide wall 13 corresponding to the inter-bore channels 9 and 10 adjacent to each other in the cylinder arranging direction have opposite directions in which the cooling water is guided to the inter-bore channels 9 and 10. It is formed in a direction. Then, to the second guide wall 12 for restricting the inflow of the cooling water flowing through the exhaust side main flow path 8 into the first inter-bore flow path 9, and the second inter-bore flow path 10 for the cooling water flowing through the exhaust side main flow path 8. The fourth guide walls 14 that promote the entry of the guides are also formed so as to guide each other in opposite directions.

As a result, in the water jacket W, as shown in FIG. 5A, the cooling water flows from the front to the rear in the pair of main flow paths 7 and 8 by the guide action of the first to fourth guide walls 11 to 14. And a flow flowing from left to right through the first inter-bore channel 9 and a flow flowing from right to left through the second inter-bore channel 10. Due to this smooth flow of the cooling water, a sufficient flow rate (also the flow rate of the cooling water per unit time) is secured in the first and second inter-bore flow paths 9 and 10, and between the bores that are difficult to cool, A structure that can efficiently cool the cylinders 2 and 2 can be realized without widening the arrangement interval.

In other words, in the first inter-bore flow path 9, the cooling water intake (water intake) promoting action by the first guide wall 11 and the drainage promoting action by the second guide wall 12 are exhibited, so that the inter-bore width is widened. It is possible to obtain an efficient water cooling effect through a sufficient flow rate. Similarly, in the second inter-bore flow path 10, since the cooling water intake (water intake) promoting action by the third guide wall 13 and the drainage promoting action by the fourth guide wall 14 are exhibited, the inter-bore width is reduced. It is possible to obtain an efficient water cooling effect through a sufficient flow rate without spreading.

In the cooling structure including the guide wall h having the configuration shown in FIG. 5A, the guide walls 11(h) and 13(h) corresponding to the inter-bore channels 9 and 10 adjacent in the cylinder arrangement direction are The directions in which the cooling water is guided to the interbore channels 9 and 10 are formed in opposite directions. Therefore, the movement path of the cooling water flowing through the two inter-bore flow paths 9 and 10 can be lengthened, and the heat absorbing action of the cooling water can be efficiently exhibited.
Further, since the guide wall h has an arcuate shape that is concentric or substantially concentric with the cylinder bores of the interbore channels 9 and 10 to which the cooling water is sent, the intercooling channels 9 and 10 can flow the cooling water more smoothly. Can be sent to.

As shown in FIGS. 2 and 3, the water jacket W includes a jacket bottom 15 and has a depth (vertical width) substantially equal to the vertical length of the barrel portion 4.
As shown in FIG. 2, between the bores, a dam wall 16 that integrates the lower halves of the adjacent barrel portions 4 and 4 is formed so as to rise up from the jacket bottom 15, and A point connecting wall 17 is formed that integrates the upper portions of the barrel portions 4 and 4 that fit together with a small cross-sectional area.

As shown in FIG. 2, the dam wall 16 which is long in the left and right and short in the front and back is provided with left and right inclined side surfaces 18 and 19 and has a trapezoidal shape with an upper constriction. It has a left-right length comparable to the left-right length. Alternatively, the sloped side surfaces 18 and 19 may be formed as vertical side surfaces and may be a rectangular dam wall 16 as viewed in the front-back direction. The cooling water that tries to flow into the interbore channels 9 and 10 is guided by the inclined side surfaces 18 and 19, so that in the interbore channels 9 and 10, the component of the flow flowing diagonally upward is promoted. Become. The upper surfaces of the interbore channels 9 and 10 may be formed as a bowl-shaped curved ceiling surface 20, so that in the interbore channels 9 and 10, the flow in the upper part is relatively promoted. It is configured.

As shown in FIG. 2 and FIG. 4, the damming wall 16 is formed in a state in which the adjacent cylinder head side portions of the barrel portions 4 forming the cylinder 2 are connected and integrated. The inter-bore channels 9, 10 are formed on the cylinder head side of the stop wall 16. The width of the dam wall 16 along the circumferential direction of the cylinder 2 is formed in a taper shape that becomes narrower toward the cylinder head side, and the taper angle γ is set to 20±5 degrees (15 degrees≦γ≦25 degrees). ..

Due to the presence of the dam wall 16 that connects the barrel portions 4 and 4 on the side opposite to the cylinder head, the height (depth) of the inter-bore channel is narrower than that of the main channels 7 and 8 and the inter-bore channels 9 and 10 are The cooling efficiency can be improved by increasing the flow rate. Further, since the taper angle γ of the damming wall 16 is set to 20±5 degrees, the left and right side walls 18 and 19 do not hinder the flow from the main flow paths 7 and 8 to the interbore flow paths 9 and 10. The cooling water can flow smoothly.

Between the upper and lower sides of the damming wall 16 and the point connecting wall 17, an upper narrowed trapezoidal lower rib wall (an example of a rib wall) 21 is formed so as to project back and forth from the outer peripheral wall 4A of the barrel portion 4. Is provided. An upper rib wall 22 is provided on the upper side of the point connection wall 17 so as to extend forward and backward from the barrel portion 4. The lower rib wall 21 and the upper rib wall 22 regulate the path width (front-rear width) of the interbore channels 9, 10 and thus have the effect of accelerating the flow rate of the cooling water and the effect of leading it upward.

As shown in FIGS. 2 and 4, the lower rib wall 21 is formed on the outer peripheral wall 4A of the barrel portion 4 so as to extend from the damming wall 16 in the axial direction of the cylinder 2 (vertical direction). The width of the cylinder 2 along the circumferential direction is narrowed as it approaches the cylinder head. That is, the lower rib wall 21 is provided in the portion between the bores 9 and 10 on the side opposite to the cylinder head side. A narrowed angle θ formed by the right and left side surfaces 21a, 21a having a small width of the lower rib wall 21 is set to 20±5 degrees (15 degrees≦θ≦25 degrees). The amount of protrusion of the lower rib wall 21 from the outer peripheral wall 4A is 0.5 to 2 mm, and preferably 0.5 to 1 mm.

Since the lower rib wall 21 is provided on the side of the inter-bore channels 9 and 10 opposite to the cylinder head (lower side), the cooling water flowing through the lower portion of the inter-bore channels 9 and 10 is guided to the cylinder head side. Therefore, it is possible to smoothly and smoothly flow the cooling water preferentially to the cylinder head side under severe thermal conditions. Since the amount of protrusion of the lower rib wall 21 is as thin as about 1 mm, there is almost no possibility of narrowing the flow paths 9 and 10 between the bores and obstructing the flow.

Since the taper angle θ of the lower rib wall 21 is set to 20°±5°, the left and right side walls 21a guide the flow across the interbore channels 9 and 10 to the cylinder head without obstructing the flow. The flow is smoothly performed, and a highly efficient cooling effect in the interbore channels 9 and 10 is obtained. Further, since the damming wall 16 and the lower rib wall 21 are continuous in the cylinder axial direction (up and down direction), both of these 16 and 21 enable intensive cooling and efficiency on the cylinder head side in the interbore channels 9 and 10. Both good cooling and smooth cooling can be performed smoothly.

Further, a drill hole 3c vertically penetrating the cylinder ceiling wall 3 is formed as an inclined hole extending obliquely upward from the bottom to the left in the middle of the upper and left sides of the inter-bore channels 9, 10. The drill holes 3c allow the flow from the tops of the interbore channels 9 and 10 to the cylinder head jacket (not shown) to increase the flow velocity in the interbore channels 9 and 10 and increase the cooling area. It is configured to enhance cooling efficiency.

Thus, between the adjacent barrel portions 4 and 4 of the water jacket W, there is the dam wall 16 in the lower half, and the upper portion of the cylinder 2 has a cross-sectional area which is about half the depth of the main flow passages 7 and 8. Are formed in the inter-bore channels 9 and 10 in the state of being located at. Barrel portions 4 and 4 are integrated with each other by the damming wall 16 and the point connecting wall 17, so that the cylinder block 1 can be improved in strength and rigidity.

As shown in FIGS. 2 and 3, the lower ends of the guide walls 11 to 14 are integrally formed so as to stand upright from the jacket bottom 15. The upper ends of the first and third guide walls 11 and 13 are located in the upper and lower middle portions of the interbore passages 9 and 10, and are 2/3 to 3/4 of the vertical width (depth) of the water jacket W. The height is set to be the height. The upper ends of the second and fourth guide walls 12 and 14 are slightly lower than the first and third guide walls 11 and 13 in the upper and lower middle portions of the interbore passages 9 and 10, and the upper and lower widths (depth) of the water jacket W are increased. The height is set to be 1/2 to 2/3 of the height.

Note that the guide wall h may have the configuration shown in FIG. That is, the third guide wall 13 is formed in an arc shape along the circumferential direction of the second cylinder 2 in the front-rear direction in the up-down direction, and protrudes from the third barrel portion 4 to the intake-side main flow path 7. ing. The fourth guide wall 14 is formed in an arc shape along the circumferential direction of the rear side third cylinder 2 when viewed in the vertical direction, and is formed to project from the second barrel portion 4 to the exhaust side main flow path 8. ing. The first and second guide walls 11 and 12 are basically the same as those in the first embodiment.

According to the guide walls 11 to 14 having this configuration, the third guide wall 13 exerts a guide action so as to promote the flow of the cooling water flowing through the intake-side main flow passage 7 to the second inter-bore flow passage 10. .. Then, by the fourth guide wall 14, the cooling water flowing from the intake side to the exhaust side (from left to right) through the second inter-bore flow passage 10 is smoothly joined to the exhaust side main flow passage 8 while being guided obliquely to the right rear. Guide action is demonstrated.

That is, as shown in FIG. 5B, the guide wall h (11 to 14) allows the cooling water to flow from left to right (from the intake side to the exhaust side) in any of the inter-bore channels 9, 10. Guided to flow. It is the same as the case shown in FIG. 5A except that the flow direction in the second inter-bore channel 10 is different. Although the flow direction is different from that in the case shown in FIG. 5A, the same effect can be achieved with respect to the water cooling effect of the interbore channels 9 and 10.

In this case, as shown in FIG. 5B, the protrusion amount of the first guide wall 11 closer to the cooling water inlet 6 than the third guide wall 13 to the intake-side main flow path 7 is set to be that of the third guide wall 13. It is convenient to make it smaller than the above and to balance the inflow amounts of the cooling water into the first and second inter-bore channels 9 and 10 so as to be equal to each other. It is also effective to make the height of the third guide wall 13 from the jacket bottom 15 (see FIG. 2) higher than that of the first guide wall 11.

In the cooling structure shown in FIG. 5B, the guide walls 11(h) and 13(h) corresponding to the inter-bore channels 9 and 10 adjacent to each other in the cylinder arranging direction pass the cooling water to the inter-bore channel. 9 and 10 are formed in a state in which the leading directions are the same. Therefore, the cooling water flows to the two inter-bore channels 9 and 10 from the intake side main channel 7 to the exhaust side main channel 8, and the smooth flow in the water jacket W improves the efficiency. The cooling effect can be obtained.

[Another embodiment]
The width of the lower rib wall 21 (width in the cylinder circumferential direction), the amount of protrusion from the outer peripheral wall 4A, or the taper angle θ can be appropriately changed and set. Similarly, the length of the lateral width, height, and taper angle γ of the dam wall 16 can be appropriately changed and set.

1 Cylinder block 2 Cylinder 4 Barrel part 4A Outer peripheral wall 9 and 10 Flow path between bores 16 Damming wall 21 Rib wall W Water jacket θ Tapered angle γ Tapered angle

Claims (6)

A plurality of cylinders arranged in a cylinder block, and a water jacket formed around the plurality of cylinders,
The water jacket has an interbore channel formed between adjacent ones of barrel portions forming the cylinder in the cylinder block ,
The rib wall extending in the axial direction of the cylinder in the flow path between the bores is formed so as to project from the outer peripheral wall of the barrel portion ,
The cooling structure for a water-cooled engine, wherein the rib wall has a tapered shape whose width along the circumferential direction of the cylinder becomes narrower as it approaches the cylinder head. The cooling structure for a water-cooled engine according to claim 1, wherein the rib wall is provided at a portion opposite to the cylinder head side in the inter-bore flow passage, which is opposite to the cylinder head side. The cooling structure for a water-cooled engine according to claim 1, wherein the tapered angle of the rib wall is set to 20±5 degrees. A damming wall is formed that connects the anti-cylinder head side portions of the adjacent barrel parts opposite to each other on the cylinder head side, and the interbore passage is formed on the cylinder head side of the damming wall. ,
The cooling structure for a water-cooled engine according to any one of claims 1 to 3, wherein a width of the damming wall along the circumferential direction of the cylinder is formed in a tapered shape that becomes narrower toward the cylinder head side. The cooling structure for a water-cooled engine according to claim 4, wherein a taper angle of the damming wall is set to 20±5 degrees. The cooling structure for a water-cooled engine according to claim 4 , wherein the rib wall is also formed so as to be raised from the damming wall .

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