JPH06346784A - Cylinder cooling structure for two-cycle engine - Google Patents

Abstract

PURPOSE:To sufficiently cool down a rib of an exhaust port by providing a guide conduit guiding a cooling liquid from a radiator to a rib conduit communicating with a conduit of a cylinder in cooling structure, in which a conduit is formed in each of a crank case and a cylinder respectively. CONSTITUTION:In cylinder cooling structure 1A, between a radiator 2 and a cylinder 12, a cooling liquid is circulated by a water pump 4 through a circulating passage 5. The cylinder cooling structure 1A is also provided with a conduit 9A formed in a crank case 8A and a conduit 10A formed in the cylinder 12. In this case, a guide conduit guiding the cooling liquid from the radiator 2 to a rib conduit 26 is arranged in an outgoing conduit equivalent part in the crank case conduit 9A. The guide conduit consists of a guide groove 28, whose point end points the rib conduit 26, a through hole 24A formed in a gasket 22A, and a part other than the through hole 24A in the gasket 22A. In this way, the cooling liquid is easily introduced to the rib conduit 26, so that the rib 24 of the exhaust port is sufficiently cooled down.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder cooling structure for a two-cycle engine. More specifically, it relates to a cylinder cooling structure for a two-cycle engine that employs a so-called water jacket.

[0002]

2. Description of the Related Art A motorcycle engine is a type of internal combustion engine that burns gasoline and uses the thermal energy of the gasoline, so that it constantly becomes hot during operation. In particular, the inside of a cylinder, which is composed of a cylinder block and a cylinder head, always reaches around 300 ° C. Therefore, if this is left alone, the piston and the Pistonton ring inside the cylinder will burn to the cylinder and become useless, so it is necessary to cool them. One of the methods for cooling the cylinder is a water cooling method using cooling water. 10 to 12 show an example of an engine structure of a conventional water-cooled motorcycle.

According to the engine 1 employing the water cooling system,
The cooling liquid cooled by the radiator 2 (shown by an arrow A in FIG. 10) is circulated between the radiator 2 and a cylinder described later by the water pump 4.
That is, the cooling fluid, the hose 6 ₁ - water pump 4
Hose 6 ₂ -Crankcase 8 (left and right cases 8a, 8
It consists of b. ) Is a waterway block consisting of a plurality of waterway blocks 10 ₁ , 10 ₂ , ... 10 _X after passing through those crankcase waterways 9 ₁ , 6 ₂ , 6 ₂ , 9 in this order, Block 12 ₁ and cylinder head 12 ₂
It flows into the cylinder water channel 10 formed inside the outer wall 12b of the cylinder 12 so as to surround and cover the hollow portion 12a of the cylinder 12. Thereafter, the coolant is returned to the radiator 2 through the hose 6 _3, circulates between the Refrigerated again by the radiator 2 and the radiator 2 and the cylinder 12 through the above path. Therefore, the high heat of about 300 ° C. that the cylinder 12 has is absorbed by the cooling liquid when the cooling liquid passes through the cylinder water channel 10, and thus the high heat of the cylinder 1
2 is cooled. Hose from radiator 2 6 ₄
Is connected to a reservoir tank (not shown).

Reference numeral 14 denotes an exhaust hole which intersects with the cylinder water passage 10 of the cylinder 12 and communicates with the hollow portion 12a of the cylinder 12 and is surrounded by the cylinder water passage 10. As can be seen from FIG. 11 and FIG. 12, the joint portion 1 of the exhaust hole 14 with the cylinder 12
A water channel block 10 ₂ which is a part of the cylinder water channel 10 is also positioned around 2 ′.

[0005] The water passage block 10 _2, the shape as the opening upright face up "U" as shown in FIG. 12 (hereinafter referred to as "upright U-shape".) The is doing. In other words, waterways block 10 _2, Fig. 1
Bottom passage 10 _2c which is located in the spaced in the lateral direction and the lower end of the vertically extending side channel 10 _2a, 10 _2b and the side passage 10 _2a, 10 _2b when directly facing the 2 connecting these 10 _2a, 10 _2b Consists of. However, since the waterway block 10 ₂ has such an upright U-shape, the sideways 10 _2a , 1
It seems as if the flow is stagnated by the dead end 10 _2a ′, 10 _2b ′ of 0 _2b , but the cooling liquid circulates between the cylinder 12 and the radiator 2 as described above. Since there is a waterway block 10 ₂
The water channel block 10 so that the coolant that has entered does not become stagnant.
₂ has a connecting water channel 15 as shown in FIGS. 11 and 12.
Is provided, and the cooling liquid is connected to another water channel block (not shown) through the connection water channel 15.

Reference numeral 22 denotes a gasket provided between the cylinder block 12 ₁ and the crankcase 8, and the gasket 22 corresponds to the side passages 10 _2a and 10 _2b of the water channel block 10 _2. Through hole 2
2 _2a and 22 _2b are formed, and the crankcase water passage 9 and the water passage block 10 ₂ are communicated with each other through the through holes 22 _2a and 22 _2b .

The crankcase water passage 9, the cylinder water passage 10 and the through holes 22 _2a and 22 _2b provided in the gasket 22 are used to form the so-called water jacket 17.
Is formed.

By the way, in order to increase the output of the two-cycle engine, it is necessary to increase the opening area of the exhaust hole 14 to smoothly discharge the exhaust gas and improve the cooling efficiency of the cylinder 12. For this purpose, the exhaust hole 14
It is conceivable to increase the opening area of the piston 20. However, if the opening area of the exhaust hole 14 is simply increased, the piston 20
When the piston slides on the inner wall 19 of the cylinder.
Due to its elasticity, the piston ring 21 fitted in 0 faces the inside of the exhaust hole 14 from the opening end 14 ′ of the exhaust hole 14. Therefore, when the piston 20 slides in the cylinder 12 and the piston ring 21 passes through the exhaust hole 14, an abnormal noise may be generated. Therefore, as shown in FIG. 12, a rib 24 having a thin cross section extending in the axial direction of the cylinder 12, that is, in the direction in which the piston 20 moves in the cylinder 12, is provided in the hollow portion 12a of the cylinder as shown in FIG. It is formed so as to face, and the existence of the rib 24 prevents the Pistonton ring 21 from facing the exhaust hole 14, thereby preventing the generation of the abnormal noise. Also, this rib 2
4, a hollow 26 is formed in the longitudinal direction thereof as shown in FIG. 12 so that the cooling liquid also flows into the hollow 26, which prevents the ribs 24 from reaching a high temperature (for example, , Japanese Utility Model Publication No. 62-40217 and Japanese Utility Model Publication No. 2-83347).

However, since the water channel block 10 ₂ of the cylinder water channel 10 disposed in the vicinity of the exhaust hole 14 has the upright U-shape as described above, the crankcase water channel 9 also corresponds to that shape. Is shaped. That is, the crankcase waterway 9, as shown in FIG. 12, a Yokomichi 9 ₁ the coolant sent from the hose 6 ₂ extended in the lateral direction, up to the water channel block 10 in _two directions Yokomichi 9 ₁ Two floodways 9 _2a and 9 _2b are formed by being almost laid down from _two floodways 9 ₂ and 9 ₂ that are raised and separated by an island portion 27. _Are arranged so as to correspond to the side passages 10 _2a and 10 _2b of the U-shaped water channel block 10 ₂ , respectively, and the outflow passages 9 _2a and 9 _2b and the side passages 10 _2a ,
10 _2b has a gentle curved shape as shown by arrows B and B in FIG. 12, respectively.
The cooling liquid from _2a and 9 _{2b flows} to the side passage 1 of the water channel block 10 _2.
It is designed to fully cover 0 _2a and 10 _2b .

[0010]

However, there is a positional relationship in which the outlet channels 9 _2a and 9 _{2b of the} crankcase channel 9 correspond to the side channels 10 _2a and 10 _2b of the channel block 10 _{2 in} this way. Coolant is by-pass 1 of water block 10 _2.
0 _2a , 10 _2b , which is sufficient, but the ribs 24 of the exhaust holes 14 are hollow (hereinafter referred to as “rib channels”) 2.
No. 6 had a problem that the cooling liquid was not sufficiently distributed. For this reason, there is a problem in that the cooling liquid does not easily flow into the rib channel 26, and the rib 24 cannot be cooled sufficiently.

The present invention has been made in view of the above-mentioned conventional problems, and the problem to be solved is to facilitate the introduction of the cooling liquid into the rib channel to cool the rib of the exhaust hole. (EN) Provided is a cylinder cooling structure for a two-cycle engine which can be sufficiently made.

[0012]

A cylinder cooling structure for a two-cycle engine according to the present invention solves the above problems and is as follows. That is, the cylinder cooling structure of the two-cycle engine of the present invention is
A crankcase water channel provided at an upper end portion of the crankcase, a cylinder water channel communicating with the crankcase water channel and formed in a cylinder integral with the crankcase and formed of a plurality of water channel blocks, the crankcase and the A water jacket, which comprises a through hole provided in a gasket located between the cylinder and the water jacket, is a part of a circulation path for circulating a cooling liquid between a radiator and the cylinder by a water pump. An exhaust hole is formed in the cylinder so as to intersect with the cylinder water channel and communicate with a hollow portion of the cylinder and surrounded by the cylinder water channel. A rib extending in the axial direction of the cylinder is formed in a central portion of the exhaust hole. Is formed so as to face the hollow portion, and a rib channel that extends in the longitudinal direction and communicates with the cylinder channel is formed in the rib, and the tip of the end of the crankcase channel faces the rib channel. The guide groove, the through hole of the gasket provided corresponding to the tip of the guide groove, and the portion of the gasket other than the through hole guide the cooling liquid from the radiator to the rib channel. It is characterized as a guide channel. In addition, a water conduit that guides the cooling liquid that has passed through the rib channel to the radiator side may be arranged on the outlet side of the rib channel that is a part of the circulation channel.

[0013]

Therefore, according to the cylinder cooling structure of the two-cycle engine of the present invention, the end of the crankcase water channel is
By the guide groove whose tip is directed to the rib channel, the through hole of the gasket provided corresponding to the tip of this guide groove, and the portion of the gasket other than this through hole, the cooling liquid from the radiator Is a guide channel that guides the rib channel to the rib channel, so that the cooling liquid that has entered the crankcase channel is advanced toward the rib channel by the guide channel.

Since the water conduit for guiding the cooling liquid passing through the rib canal to the radiator side is arranged on the outlet side of the rib canal which is a part of the circulation channel, the cooling liquid discharged from the rib canal mainly enters the water conduit and The cooling liquid that has entered the water conduit is guided toward the radiator side in the circulation path.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A cylinder cooling structure 1A for a two-cycle engine according to the present invention will be described in detail below with reference to the accompanying drawings with reference to the drawings. Since the present invention is different from the prior art in that the guide means for guiding the cooling liquid to the rib channel is formed and the portion related thereto, the different portion will be described and the other same portions will be the same. The reference numerals are given and the description is omitted. Therefore, regarding FIGS. 10 to 12 used in the description of the prior art section,
The present invention described below is also applicable.

(Embodiment 1) FIGS. 1 to 6 show a first embodiment of a cylinder cooling structure for a two-cycle engine according to the present invention. FIG. 1 is an overall side view, and FIG. 2 is a direction of arrow II in FIG. 3 is a perspective view seen from FIG. 3, FIG. 3 is a sectional view taken along line III-III of FIG.
3 is an enlarged view of a region IV in FIG. 3, FIG. 5 is a plan view of a crankcase, FIG. 6 is a plan view of a gasket, FIG. 7 is a view showing a modification of FIG. 6, FIG. 8 is a view showing a second embodiment, and FIG. 9 is a diagram showing a third embodiment.

According to the cylinder cooling structure 1A for the two-cycle engine of the present invention, the water jacket 17A, which is a part of the circulation path 5 for circulating the cooling liquid between the radiator 2 and the cylinder 12 by the water pump 4,
A crankcase water channel 9A provided at an upper end portion 8Aa of the crankcase 8A and a cylinder 12 communicating with the crankcase water channel 9A and integrated with the crankcase 8A.
Is formed inside of and a plurality of waterways blocks 10 ₁ - 10
It is composed of a cylinder water channel 10A consisting of A ₂ ... 10 _X and through holes 24A, 24A provided in a gasket 22A located between the crankcase 8A and the cylinder 12 for communicating the crankcase water channel 9A and the cylinder water channel 10 with each other. . The through holes 24A, 24A may be combined into one large track-shaped hole.

In the crankcase water channel 9A,
Outflow channel 9 of crankcase channel 9 described in the section of prior art
_2a, crankcase waterway 9A is a portion corresponding to 9 _2b
The portions 9A _2a and 9A _2b of the guide grooves 28 and 28 having the tip (the tip here means the end in the direction in which the cooling liquid flows) of the rib channel 26 and the gasket 22A. Through holes 24A, 24A and through holes 24A,
A guide water channel 30 is provided which is formed by a portion 22Aa of the gasket 22A other than 24A and which guides the cooling liquid from the radiator 2 to the rib water channel 26.

The guide groove 28 is formed in the island portion 27A,
As shown in FIG. 4, it comprises a flat surface portion 28a and a sloped surface portion 28b. By appropriately changing the inclination angle of the inclined surface portion 28b with respect to the flat surface portion 28a, the flow direction of the cooling liquid toward the rib water channel 26 is determined. Also,
The number of guide channels 30 does not have to be two, and may be one as shown in FIG. 7. In this case, the flat surface portion 28a of the guide groove 28 is lengthened so that the tip of the guide groove 28 is located almost directly below the rib channel 26, and the inclination angle of the inclined surface portion 28b with respect to the flat surface portion 28a is approximately 90 °. To do so. As a result, the cooling liquid flows toward the rib water channel 26 from directly under the rib water channel 26. Further, as a matter of course, the number of the through holes 24A of the gasket 22A is also one.

The water conduit 32 is provided to facilitate the introduction of the cooling liquid through the rib channel to the outlet side of the rib channel 26, which is a part of the circulation channel 5, to further cool the rib 24. It is fixed to the cylinder head 12 ₂ by a fixing means. The end 32a of the rib channel side
In the cylinder barrel outer circumference 34 that contacts the upper wall surface of the cylinder 12 and faces the outlet of the rib channel 26 and is separated by an appropriate distance (in this embodiment, the separation distance is indicated by symbol S. The separation). Distance S is rib 24
The length is appropriately determined depending on the cooling degree. That is, the smaller the separation distance S is, the larger the amount of the cooling liquid passing through the rib 24 is, so that the rib 24 is cooled. ) It has been straightened upward. Then, the end 32b on the side opposite to the rib is located at the opening 3 of the water outlet cap 36 of the cylinder head 12 _2.
It is placed in 6a. The water outlet cap 36 is in communication with the radiator 2 via a radiator inlet hose 38.

As described above, according to the first embodiment of the cylinder cooling structure for the two-cycle engine of the present invention, since the guide water passage 30 is formed, the cooling liquid which has entered the crankcase water passage 9A is guided by the guide water passage 30. By rib channel 2
It will flow toward 6. Therefore, the rib channel 2
The cooling liquid can be easily introduced into the cooling holes 6, and the ribs 24 of the exhaust holes 14 can be sufficiently cooled.

Further, the rib channel end 32a of the water conduit 32 is provided.
Face the outlet of the rib channel 26, and the non-rib channel end 32b is attached to the water outlet cap 36.
Since it is inside, the cooling liquid easily enters the water guiding pipe 32, and the cooling liquid flows vigorously inside the water guiding pipe 32 by receiving the suction force on the negative pressure side of the water flow by the water pump 4. As a result, the flow of the cooling liquid in the rib channel 26 also becomes faster, so that the cooling effect of the rib 24 can be enhanced.

Further, since the cooling effect of the ribs also improves the cooling performance of the entire cylinder, the gap between the piston and the cylinder can be further reduced, and so-called cylinder noise when the piston moves in the cylinder is generated. Occurrence can be effectively prevented. The reference numeral 33 indicates the left and right cases 8l, 8 of the crankcase 8.
It is a case mating surface of r.

(Second Embodiment) FIG. 8 shows a second embodiment. Since the second embodiment is different from the first embodiment only in the portion corresponding to the water conduit 32 and the portion related thereto, the same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

According to the cylinder cooling structure 1B of the two-cycle engine according to the second embodiment, the water conduit 32 of the first embodiment is provided.
The water conduit 32B corresponding to the above is integrally or integrally coupled to the rib 24 so that the length of the rib 24 is substantially increased. Therefore, the cooling liquid passing through the ribs 24 is surely guided into the water outlet cap 36.
Therefore, according to the second embodiment, the cooling effect of the rib 24 can be further enhanced. Further, the auxiliary hole 38 allows a new flow of the cooling liquid to be formed around the water conduit 32 on the outer periphery 34 of the cylinder barrel, which also improves the cooling effect.

(Third Embodiment) FIG. 9 shows a third embodiment. The third embodiment is different from the first embodiment only in that a water conduit 32C corresponding to the water conduit 32 of the first embodiment is longer than the water conduit 32 and a related portion due to the difference, and thus the other same. The same reference numerals are given to the parts and the description thereof will be omitted.

According to the cylinder cooling structure 1C for a two-cycle engine according to the third embodiment, the length of the water conduit 32C is set so as to protrude from the water outlet cap 36C corresponding to the water outlet cap 36 in the first embodiment. It is, are communicated both 40,2a hose 6 ₅ is interposed between the Roatanku 2a of the protruding part is a water outlet 40 and the radiator 2. Note that reference numerals 42 and 44 indicate a union and a union pipe, respectively, and the hose 6
₅ is connected to the radiator 2.

Therefore, according to the cylinder cooling structure 1C of the two-cycle engine according to the third embodiment, the water outlet 40-
Hose 6 ₅ - that Roatanku 2a, since dedicated path for cooling ribs 24 (short circuit) is formed, it is possible to further enhance the cooling effect of the further ribs 24.

[0029]

According to the cylinder cooling structure of the two-cycle engine of the present invention, since the guide water passage is formed, the cooling liquid having entered the crankcase water passage can be advanced toward the rib water passage. Therefore, it is possible to facilitate the introduction of the cooling liquid into the rib channel and to sufficiently cool the rib of the exhaust hole. In addition, since a water conduit that guides the cooling liquid that passed through the rib canal to the radiator side is arranged on the outlet side of the rib canal, which is a part of the circulation channel, the cooling liquid that comes out of the rib canal will enter almost only the water conduit. Therefore, the cooling liquid that has entered the water guide pipe is guided toward the radiator side in the circulation path. Therefore, the cooling effect of the ribs can be further enhanced. Further, since the cooling effect of the ribs is improved, the cooling performance of the entire cylinder is also improved, so that the gap between the piston and the cylinder can be further reduced. Therefore, it is possible to effectively prevent generation of so-called cylinder noise when the piston moves in the cylinder.

[Brief description of drawings]

FIG. 1 is an overall side view.

FIG. 2 is a perspective view as seen from the direction of arrow II in FIG.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is an enlarged view of a region IV in FIG.

FIG. 5 is a plan view of a crankcase.

FIG. 6 is a plan view of a gasket.

FIG. 7 is a diagram showing a modification of FIG.

FIG. 8 is a diagram showing a second embodiment.

FIG. 9 is a diagram showing a third embodiment.

FIG. 10 is an overall perspective view showing a conventional technique.

FIG. 11 is a vertical sectional view of a cylinder.

12 is a sectional view taken along line XII-XII in FIG.

[Explanation of symbols]

1A Two-cycle engine cylinder cooling structure 2 Radiator 4 Water pump 5 Circulation path 8A Crankcase 8Aa Upper end of crankcase 9A Crankcase water channel 10 Cylinder water channel 10 ₁ Water channel block 10A ₂ 〃 10 _X 〃 10A Cylinder block 12 Cylinder 12a Cylinder hollow Part 14 Exhaust hole 17 Water jacket 22A Gasket 22Aa Gasket part 24 Rib 24A Gasket through hole 26 Rib channel 28 Guide groove 30 Guide channel

Claims (2)

[Claims] 1. A crankcase water channel provided at an upper end portion of a crankcase, and a cylinder water channel communicating with the crankcase water channel and formed inside a cylinder integral with the crankcase and including a plurality of water channel blocks. A water jacket consisting of a through hole provided in a gasket located between the crankcase and the cylinder, which is a part of a circulation path for circulating a cooling liquid between a radiator and a cylinder by a water pump. In a cylinder cooling structure for a two-cycle engine, the cylinder has an exhaust hole that intersects with the cylinder water channel and communicates with a hollow portion of the cylinder and is surrounded by the cylinder water channel. A rib extending in the axial direction of the cylinder in the central portion Is formed so as to face the hollow portion, and a rib channel that extends in the longitudinal direction and communicates with the cylinder channel is formed in the rib, and the tip of the end of the crankcase channel faces the rib channel. The guide groove, the through hole of the gasket provided corresponding to the tip of the guide groove, and the portion of the gasket other than the through hole guide the cooling liquid from the radiator to the rib channel. A cylinder cooling structure for a two-cycle engine characterized by being used as a guide channel. 2. A cylinder cooling system for a two-cycle engine according to claim 1, wherein a water pipe for guiding the cooling liquid passing through the rib channel to the radiator side is arranged on the outlet side of the rib channel which is a part of the circulation channel. Construction.