JPH09177599A - Cooling device for siamese cylinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To strongly cool the part closer to a head of a continuous thick wall part to relatively reduce the size and weight of a multiple cylinder engine and increase the output of the engine, and easily tamp casting sand within a cooling water passage situated between jacket communicating passages. SOLUTION: A water passage forming member 10 is casted to the continuous thick wall part 5 of a Siamese cylinder, and the cooling water of a cylinder jacket is discharged to a head jacket through the water passage forming member 10. The water passage forming member 10 has lateral jacket communicating passages 12, 12, lateral cooling water inlet parts 13, 13 opened toward the cylinder jacket, and non-cavity parts 11 and cooling water passages 15 alternately formed in vertical multistage. A casting sand tamping hole 12a is provided on at least one outside surface of the lateral outside surfaces of the jacket communicating passages 12, 12 in opposition to each cooling passage 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling system for a Siamese cylinder of a multi-cylinder engine, in which the strength of a continuous wall portion of the cylinder is increased, and the head side portion is strongly cooled so that the multi-cylinder engine is relatively small. We provide products that can reduce weight and increase output.

[0002]

2. Description of the Related Art In recent years, it has been necessary to reduce the size and weight of a multi-cylinder engine so that the intervals between the cylinder bores are narrowed, or to increase the displacement to increase the engine output. Siamese cylinders whose wall thickness is as thin as possible have been adopted. Examples of conventional techniques of this kind include, for example, SAIKAI Sho 59
The one disclosed in Japanese Patent Publication No.-68155 is known.

FIG. 6 shows the above-mentioned conventional example. FIG. 6A is a longitudinal sectional view of a main part of a Siamese cylinder, and FIG. 6B is a cross-sectional plan view taken along the line BB in FIG. 6A. (C) of the figure shows the head-side portion 4a of the continuous wall portion 4 of the Siamese cylinder.
It is a perspective view of the water channel formation member cast in. In this conventional example, a plurality of cylinders 3 are arranged side by side in a front and rear direction in a cylinder block 1, and adjacent cylinders 3 and 3 are connected by a continuous wall portion 4 to form a siamese cylinder 2 so that the siamese cylinder 2 is surrounded. A cylinder jacket 8 is formed in the above, and a water channel forming member 10 is cast in the continuous wall portion 4.

The water channel forming member 10 is shown in FIGS. 6 (A) and 6 (B).
As shown in (C), a cooling water passage 15 that communicates the left and right cylinder jackets 8 of the continuous wall portion 4, and a pair of left and right cooling water passages 15 that are located at both left and right ends of the cooling water passage 15 and communicate with the cooling water passage 15. And a pair of left and right cooling water introducing portions 13 and 13 which are located below the respective jacket communication passages 12 and 12 and open toward the respective cylinder jackets 8 and 8. The cooling water that has flowed in from the cooling water introduction portion 13 flows through the cooling water passage 15 and also to the head jacket (not shown) located above the head leaning portion 4a via the jacket communication passage 12. It flows out, and in the meantime, the head leaning part 4 of the continuous meat wall part 4
It is configured to cool a.

In the above conventional example, since the cooling water passage 15 is flat, there is a risk of insufficient strength in the corresponding portion of the cooling water passage 15 in the machining of the cylinder bore 3a, which in turn causes local distortion of the cylinder bore 3a. . In order to avoid this, it is necessary to increase the thickness of the continuous wall portion 4 to some extent. That is, in this conventional example, since the wall thickness of the continuous wall portion 4 cannot be made sufficiently thin,
There is a problem in narrowing the interval between the cylinder bores 3a or increasing the displacement to increase the output of the engine.

Further, the cooling water introducing portion 13 is formed by cutting out the lower portion of each jacket communication passage 12, but since the cooling water introducing portion 13 has a small frontage, a large amount of cooling water is introduced into the cooling water passage 15. It cannot be introduced smoothly. Therefore, there is a problem that the flow velocity in the cooling water passage 15 cannot be increased and the head-side portion 4a of the continuous wall portion 4 cannot be cooled strongly. As described above, if the head-side portion 4a of the continuous wall portion 4 cannot be strongly cooled and the heat radiation ability is low, it is impossible to increase the output of the engine.

That is, the piston ring (not shown) is cooled through the cylinder wall. However, if the heat radiating ability of the head-side portion 4a is low, the top ring is particularly attached to the top of the piston in order to prevent seizure of the piston ring. There is no choice but to mount it at a certain distance from the surface. This means that a ring-shaped dead space that does not contribute to combustion occurs on the outer circumference of the piston top. For this reason, it is not possible to improve the air utilization rate, which in turn cannot increase the output of the engine. In particular, in recent years, it has been demanded to further reduce the size and weight of the engine and increase the output of the engine.
We cannot fully meet these demands.

Therefore, in order to solve the above-mentioned difficulties, the applicant of the present invention has previously proposed a water channel forming member as shown in FIG. 5 (Japanese Patent Application No. 7-60818: hereinafter referred to as a previously proposed example). The water channel forming member 10 includes a pair of left and right jacket communication passages 12 and 12 located in the upper half and the jacket communication passage 12 described above.
・ A pair of left and right cooling water introduction parts 13 ・ 13 located below 12 and opening toward each cylinder jacket 8 ・ 8,
Between the left and right jacket communication passages 12 and 12 and between the left and right cooling water introduction portions 13 and 13, respectively, a non-hollow portion 11 and a hollow portion that constitutes the cooling water passage 15 are alternately formed in a multistage structure. There is.

According to the previously proposed example, the non-hollow portion 11
Functions as a rib that mechanically reinforces the continuous wall portion 4, so that the cooling water passages 15 formed alternately with the non-hollow portions 11 in the upper and lower stages are compared with the flat and vertically long cooling water passages 15 of the conventional example. The mechanical strength of the cylinder bore 3
There is no possibility that partial distortion will occur in the hole machining of a. Further, since the frontage of the pair of left and right cooling water introduction portions 13 is large, a large amount of cooling water is introduced to enhance the cooling effect, the head side portion 4a is strongly cooled, and the piston ring is inserted through the cylinder wall. Cool strongly. This makes it possible to bring the top ring as close as possible to the top surface of the piston and minimize the ring-shaped dead space that does not contribute to combustion on the outer circumference of the piston to improve the air utilization rate.

Further, according to the above proposed example, the position of the piston pin is brought as close as possible to the piston top surface as the top ring is brought as close as possible to the piston top surface, and the crankshaft is moved by that much. The swinging length can be increased, and the piston stroke and eventually the displacement can be increased without changing the connecting rod or engine physique (height). That is, it is possible to reduce the size of the multi-cylinder engine relatively and increase the output of the engine. On the contrary, when the piston stroke is not changed, the connecting rod can be set longer as much as the position of the piston pin is closer to the top surface of the piston, so that the piston side pressure can be reduced and, as a result, the friction loss can be reduced.

[0011]

However, the above-mentioned proposed example has the following problems. That is, when the water channel forming member 10 is cast into the head-side portion 4a of the continuous wall portion 4, it is necessary to previously fill the jacket communication channel 12 and the cooling water channel 15 of the water channel forming member 10 with the casting sand. And there is no problem in the case where the molding sand is press-fitted with high pressure air and packed by a blow molding machine, etc.
When packing sand in the cooling water passage 15 formed in multiple stages by a manual molding machine, the left and right jacket communication passages 12,
It is not possible to tamper with the casting sand in the cooling water passage 15 located between the twelve. The present invention has been made in view of such circumstances, and when the casting sand in the cooling water passage located between the jacket communication passages is packed, the casting sand can be easily compacted. This is a technical issue.

[0012]

In order to solve the above problems, the present invention is configured as follows. That is, the basic configuration of the cooling device for the Siamese cylinder according to the present invention is the head-side portion 4 of the continuous wall portion 4 of the Siamese cylinder 2.
The water channel forming member 10 is cast into a and the cylinder jacket 8
The cooling water in 8 is configured to flow out to the head jacket 22 located above the continuous meat wall portion 4 via the water channel forming member 10.

According to the first aspect of the present invention, in the Siamese cylinder cooling device having the above basic structure, the water channel forming member 10 includes a pair of left and right jacket communication channels 12 and 12 located in an upper half portion, and the jacket. Communication passage 1
Located on the lower side of 2/12, each cylinder jacket 8.8
Pair of left and right cooling water inlets 13, 13 opening toward
And between the left and right jacket communication passages 12 and 12 and between the left and right cooling water introduction portions 13 and 13, respectively, a non-cavity portion 11 and a cavity portion forming the cooling water passage 15 which are alternately formed in upper and lower stages. It is equipped with the above-mentioned jacket communication passage 12.1.
The at least one outer surface of the left and right outer surfaces of 2 is provided with a hole 12a for sand filling, and the hole 12a for sand filling is opened so as to oppose each cooling water passage 15 formed in multiple stages. .

According to a second aspect of the present invention, in the cooling device for the Siamese cylinder according to the first aspect, the cooling water passages 15 are bilaterally symmetrical so that the tips formed in a wedge shape in plan view face the center. In addition to being configured, the wedge-shaped tip portions are communicated with each other through a minute gap S.

[0015]

According to the invention described in claim 1, in addition to the same operation and effect as the invention according to the previously proposed example, the jacket communication passage 12
A hole 12a for sand filling is formed in at least one of the left and right outer surfaces of the outer surface 12, and the hole 12a for sand filling is opened so as to face the cooling water passages 15 formed in multiple stages. When the casting sand in the cooling water passage 15 located between the communication passages 12 is packed, the casting sand can be easily compacted.

In the invention according to claim 2, since the respective cooling water passages 15 are configured symmetrically so that the tips formed in a wedge shape in plan view face the center, the thickness of the continuous wall portion 4 is increased. In the thinnest central portion, the water channel forming member 10 can be made even thinner, and thus the continuous wall portion 4 can be made as thin as possible. As a result, the wall thickness of the continuous wall portion 4 can be further reduced, and the pitch between the cylinder bores can be reduced. Further, since the wedge-shaped tips of the cooling water passages 15 are communicated with each other through the minute gaps S, when the casting sand is packed in the cooling water passages 15, the casting sand can be easily tamped from the left and right sides. You can

[0017]

Embodiments of the present invention will be described below with reference to the drawings. 1 shows a water channel forming member according to a first embodiment of the present invention, FIG. 1 (A) is a perspective view of the water channel forming member, and FIG. 1 (B) is a plan view in which the right half of the water channel forming member is broken. FIG. 1C is a side view of the water channel forming member. FIG. 2 shows a main part of a vertical multi-cylinder engine equipped with a cooling device for a Siamese cylinder according to the present invention,
2A is a partial vertical cross-sectional view, and FIG. 2B is a partial plan view of the cylinder block. Further, FIG. 3 is a vertical cross-sectional view of a main part of a vertical multi-cylinder engine equipped with a cooling device for a Siamese cylinder according to the present invention.

In this vertical multi-cylinder engine E, as shown in FIG. 3, a cylinder head 20 is fixed with a head bolt 6 on a cylinder block 1 integrally formed with a crankcase, and a cylinder formed in the cylinder block 1 is provided. The jacket 8 and the head jacket 22 formed on the cylinder head 20 are communicated with each other through a large number of jacket communication holes 24 formed in a portion other than the continuous wall portion 4, and the cylinder head 20 is cooled with cooling water that has cooled the cylinder block 1. Is configured to.

The cooling device for the Siamese cylinder according to the present invention has the same structure as the previously proposed example. That is, as shown in FIG. 2 and FIG. 3, a plurality of cylinders 3 are arranged side by side in the cylinder block 1 in the front-rear direction, and adjacent cylinders 3 and 3 are connected by a continuous wall portion 4 to form a siamese cylinder 2. A cylinder jacket 8 is formed so as to surround the Siamese cylinder 2. A water channel forming member 10, which will be described later, is cast into the continuous wall portion 4.

As shown in FIGS. 1 and 2, the water channel forming member 10 has two metal plate-like bodies 10a, 10a symmetrically formed by press-molding, which are overlapped with each other so as to face each other. The outer edge joints 17 and 17 formed by projecting in the outer vertical direction at the outer edges of the communication passages 12 and the non-hollow portions 11 are arc spot welded to be integrally formed. Thereby, the two metal plate-shaped bodies 10a formed in the same shape can be simply and inexpensively manufactured by simply fixing them to each other. It should be noted that the seam welding of the second embodiment described later and the arc spot welding may be replaced with each other.

The water channel forming member 10 is located at a pair of left and right jacket communication passages 12 and 12 located in the upper half portion and below the jacket communication passages 12 and 12, and is directed toward each cylinder jacket 8 8. A pair of left and right cooling water inlets 13 and 13 that open and the left and right jacket communication paths 12 and 12 and the left and right cooling water inlets 13 and 13 that are alternately formed with the non-cavity portions 11a and the cooling Cylinder jacket 8, 8 comprising a cavity forming a water channel 15.
The cooling water therein flows out to the head jacket 22 located above the continuous meat wall portion 4 through the pair of left and right cooling water introduction portions 13, 13, the cooling water passages 15, 15, and the jacket communication passages 12, 12 in order. Is configured to let.

The non-hollow portion 11a formed in the upper and lower multi-steps functions as a rib for mechanically reinforcing the continuous wall portion 4, and the cooling water passages 15 alternately formed in the non-hollow portion 11a are formed in the upper and lower multi-steps. The mechanical strength is remarkably increased as compared with the flat and vertically long cooling water passage 15 of the example. As a result, there is no possibility that partial distortion will occur in the drilling of the cylinder bore 3a.

The characteristic features of the present invention will be described below. A hole 12a for filling sand with sand is formed in the outer surface of one of the jacket communication paths 12, 12. The casting sand filling hole 12a is opened so as to face each of the cooling water passages 15 formed in multiple stages, and when the casting sand in the cooling water passage 15 located between the jacket communication passages 12 is packed, Cast sand can be easily compacted.

The pair of left and right cooling water introduction parts 13 and 13 are provided with a pair of front and rear cooling water guide plates 14 and 14 which are provided on the left and right sides, respectively.
The outer peripheral surfaces 3b of the cylinders 3 and 3 adjacent to each other in the front and rear
-It is constructed by expanding along 3b. As a result, the frontage of the cooling water introducing portions 13 is formed large. Therefore, most of the cooling water is the cylinder jacket 8.8.
A large amount of water flows into the cooling water passage 15 and the jacket communication passage 12 from the cooling water introduction portion 13 that is expanded toward the head, and the head is located above the continuous meat wall portion 4 through the jacket communication passage 12 and 12. Exit to the jacket 22.

That is, since the piston ring can be strongly cooled through the cylinder wall by powerfully cooling the head side portion 4a, the top ring can be brought as close as possible to the piston top surface to burn the outer periphery of the piston top. The ring-shaped dead space that does not contribute can be minimized to improve the air utilization rate. Further, along with this, the sticking of the top ring due to the carbonization of the unburned portion of the fuel can be eliminated.

Moreover, the position of the piston pin is moved as close as possible to the piston top surface as the top ring is moved as close as possible to the piston top surface, and the swinging dimension of the crankshaft is lengthened accordingly. The connecting rod engine can be made relatively small without changing its height and the piston stroke can be increased to increase the displacement. Further, since the head-side portion 4a can be strongly cooled, the exhaust amount can be increased by increasing the diameter of the cylinder bore 3a. Further, by applying the present invention to a multi-cylinder engine equipped with a turbocharger, it is possible to achieve relative miniaturization and increase in engine output. On the contrary, when the piston stroke is not changed, the connecting rod can be set longer as much as the position of the piston pin is closer to the top surface of the piston, so that the piston side pressure can be reduced and, as a result, the friction loss can be reduced.

FIG. 4 shows a water channel forming member according to a second embodiment of the present invention, FIG. 4 (A) is a perspective view of the water channel forming member, and FIG. 4 (B) is a broken right half of the water channel forming member. A plan view and FIG. 4C are side views of the water channel forming member. In this embodiment, as shown in FIG. 4, the outer edge joints 17 and 17 formed by projecting in the outer longitudinal direction on the outer edges of the left and right jacket communication passages 12 and the non-cavity portions 11 at the lower end. Are seam welded together and fixed together. Further, the same sand sand filling hole 12a as that of the water channel forming member according to the first embodiment is formed in one outer surface of the jacket communication passages 12, 12. Hereinafter, differences from the water channel formation member according to the first embodiment will be described.

As shown in FIG. 4 (A), the non-hollow portion 11a formed in multiple stages has front and rear wall connecting holes 16 formed in a long hole.
Having. As a result, there is an advantage that the continuous wall portion 4 can more strongly oppose the pressure applied to the continuous wall portion 4 during the processing of the cylinder bore or the engine operation. In addition, as shown in FIGS. 4A and 4B, each cooling water passage 15 is formed in a wedge shape in a plan view, and is symmetrically configured so that its tip faces the center.

That is, the wall thickness of the continuous wall portion 4 is thinnest in the central portion and thickest in the left and right end portions, but the cooling water passage 15 is flattened in correspondence with the wall thickness of the continuous wall portion 4. The water channel forming member 10 can be made thinner than the conventional example by forming it in a wedge shape and being symmetrically configured so that its tip faces the center, and thus the continuous wall portion 4 can be made even thinner. As a result, the pitch between the cylinder bores can be reduced. Alternatively, by increasing the diameter of the cylinder bore, it is possible to increase the exhaust amount and thus the output.

The pair of left and right cooling water passages 15 are shown in FIG.
As shown in (B) and (C), since the central portion (wedge-shaped tip portion) is formed so as to communicate with each other through the minute gap S, for example, a wedge-shaped cooling water channel is formed by a manual molding machine. When the casting sand is packed in 15, it is convenient because it can be compacted from one side in the left-right direction. The upper edge 15b of the wedge-shaped cooling water passage 15 is formed in an upward slope outward in the left-right direction. That is, each wedge-shaped cooling water channel 1
Even if the cooling water boils in 5 to generate water vapor, the water vapor has an upper edge 15b of each cooling water passage 15 formed in an upward gradient.
The cooling performance is maintained high because it moves upward along the path and escapes to the head jacket 22 through the jacket communication passage 12.

[Brief description of the drawings]

1 shows a water channel forming member according to a first embodiment of the present invention, FIG. 1 (A) is a perspective view of the water channel forming member, and FIG. 1 (B) is a cutaway right half of the water channel forming member. Top view, Figure 1
1C is a vertical cross-sectional view taken along the line C-C in FIGS. 1A and 1B.

FIG. 2 shows a main part of a vertical multi-cylinder engine equipped with a Siamese cylinder cooling device according to the present invention.
FIG. 2A is a partial vertical sectional view thereof, and FIG. 2B is a partial plan view of the cylinder block.

FIG. 3 is a vertical cross-sectional view of a main part of a vertical multi-cylinder engine equipped with a cooling device for a Siamese cylinder according to the present invention.

FIG. 4 is a view corresponding to FIG. 1 showing a water channel forming member according to a second embodiment of the present invention.

FIG. 5 is a view corresponding to FIG. 1 showing a water channel forming member according to the previously proposed example.

6 shows a conventional example, FIG. 6 (A) is a vertical cross-sectional view of a main part of a Siamese cylinder of a vertical engine, and FIG. 6 (B) is a cross-sectional plane taken along the line BB in FIG. 6 (A). FIG. 6C is a perspective view of the water channel forming member.

[Explanation of symbols]

1 ... Cylinder block, 2 ... Siamese cylinder, 3
... Cylinder 3a ... Cylinder bore 3b ... Cylinder outer peripheral surface 4 ... Continuous wall portion 4a ... Head portion of continuous wall portion 8 ... Cylinder jacket 10 ... Water channel forming member,
11. 11a ... Non-hollow part, 12 ... Jacket communication passage, 1
2a ... Hole for casting sand filling, 13 ... Cooling water introduction part, 15 ... Cooling water channel, 22 ... Head jacket, S ... Minute gap.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hoichi Kamata 64 Ishizukitamachi, Sakai City, Osaka Prefecture Kubota Sakai Co., Ltd. (72) Nobuhiro Yamamoto 64, Ishizukitamachi, Sakai City, Osaka Prefecture Kubota Sakai Co., Ltd. (72) ) Inventor Kazuyoshi Morioka 64 Ishizukitamachi, Sakai City, Osaka Prefecture, Kubota Sakai Co., Ltd.

Claims (2)

[Claims] 1. A water channel forming member (1) is provided at a head portion (4a) of a continuous wall portion (4) of a siamese cylinder (2).
0) is cast, and cooling water in the cylinder jackets (8) (8) is located above the continuous wall portion (4) via the water channel forming member (10) and the head jacket (22).
In the cooling device of the Siamese cylinder configured to flow out to the above, the water channel forming member (10) includes a pair of left and right jacket communication passages (12) (12) located in the upper half portion, and the jacket communication passage (12). A pair of left and right cooling water introduction portions (13) and (13) located below the (12) and opening toward the cylinder jackets (8) and (8), and left and right jacket communication passages (12) and (12). Between and on the left and right cooling water inlets (1
3) (13), the non-cavity portion (11) and the cavity portion forming the cooling water channel (15) which are alternately formed in upper and lower stages are provided between the jacket communication passages (12) and (12). ), A hole for filling with sand (12a) is formed in at least one of the outer side surfaces, and the hole (12a) for filling with sand is opened so as to face each of the cooling water channels (15) formed in multiple stages. A cooling device for a Siamese cylinder characterized by the above. 2. The cooling water passages (15) are bilaterally symmetrical so that the tips formed in a wedge shape in plan view face toward the center, and the wedge tips have a minute gap (S).
The cooling device for the siamese cylinder according to claim 1, which is in communication with each other via a.