JP3028705B2 - Two-cycle engine cylinder cooling structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A motorcycle engine burns gasoline and is a type of internal combustion engine that utilizes the heat energy thereof. In particular, the inside of a cylinder composed of a cylinder block and a cylinder head always reaches about 300 ° C. Therefore, if left alone, the piston and the piston ring inside the cylinder are burned to the cylinder and become useless, so it is necessary to cool them. One of the methods for cooling a cylinder is a water cooling method using cooling water. 10 to 12 show an example of an engine structure of a motorcycle employing a conventional water cooling system.

According to the engine 1 employing the water cooling system,
The cooling liquid cooled by the radiator 2 (indicated by an arrow A in FIG. 10) is circulated by the water pump 4 between the radiator 2 and a cylinder described later.
That is, the coolant is supplied to the hose 6 ₁ -water pump 4-
Hose 6 ₂ - after undergoing (. Left not shown, consisting of the right case) crankcase 8 forward in their 6 ₁ crankcase waterway 9 formed on the upper end portion of the 4,6 _2, 9, a plurality of waterways blocks a waterway consisting _{10 1 · 10 2 · ... 10} X, the cylinder block 12 ₁ and the cylinder head 12 ₂
The fluid flows into a cylinder 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 (see FIG. 11). Thereafter, the coolant is returned through a hose 6 ₃ (see FIG. 10) to the radiator 2, 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. which the cylinder 12 has is caused by the cooling liquid flowing through the cylinder channel 1.
When passing through zero, the cylinder 12 is cooled because it is absorbed by the cooling liquid. Hose 6 ₄ coming out of the radiator 2 are those leading to a reservoir tank (not shown).

Reference numeral 14 denotes an exhaust hole which crosses the cylinder water passage 10 of the cylinder 12 (see FIG. 11), communicates with the hollow portion 12a of the cylinder 12, and is surrounded by the cylinder water passage 10. As it can be seen from FIGS. 11 and 12, waterways block 10 ₂ which is part of the cylinder water passage 10 to the periphery of the joint 12 'of the cylinder 12 of the exhaust hole 14 is located.

[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 are doing. In other words, the waterway block 10 ₂
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, waterway block 10 _2, because it such a upright U-shape, at first glance the side path 10 _2a, 1
It seems as if the flow is stagnated by the dead ends 10 _2a ′, 10 _2b ′ of O _2b , but the coolant circulates between the cylinder 12 and the radiator 2 as described above. There is a waterway block 10 ₂
The water block 10
₂ includes a connection channel 15 as shown in FIG. 11 and FIG.
The coolant is connected to another water channel block (not shown) via the connection water channel 15.

[0006] indicates the sign 22 is a gasket disposed between the cylinder block 12 ₁ and the crankcase 8, the gasket 22 corresponding to the bypass 10 _2a, 10 _2b waterways block 10 ₂ Through hole 2
2 _2a, 22 _2b, is formed, are communicated crankcase waterway 9 and waterways block 10 ₂ are communicated via the through hole 22 _2a, 22 _2b.

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

Incidentally, in order to increase the output of the two-stroke engine, it is necessary to increase the opening area of the exhaust hole 14 so as to discharge the exhaust gas smoothly and to increase the cooling efficiency of the cylinder 12. For this reason, the exhaust holes 14
It is conceivable to increase the opening area of the piston 20.
When the piston slides on the inner wall 19 of the cylinder, the piston 2
The elasticity of the piston ring 21 fitted to zero causes the opening end 14 ′ of the exhaust hole 14 to reach the inside of the exhaust hole 14. For this reason, when the piston 20 slides in the cylinder 12 and the piston ring 21 passes through the exhaust hole 14, there is a possibility that an abnormal noise may be generated. For this reason, as shown in FIG. 12, a rib 24 having a narrow cross section extending in the axial direction of the cylinder 12, that is, the direction in which the piston 20 moves in the cylinder 12, is provided in the center of the opening of the exhaust hole 14 in the hollow portion 12a of the cylinder. The piston 24 is formed so as to face the piston ring 21.
Is prevented from reaching the exhaust hole 14 so as to prevent the generation of the abnormal noise. The rib 24 has a hollow 26 in its longitudinal direction as shown in FIG.
Is formed so that the cooling liquid flows through the hollow 26, thereby suppressing the temperature of the ribs 24 from becoming high (for example, Japanese Utility Model Laid-Open No. 62-40217 and Japanese Utility Model Laid-Open No. 2-83347). Gazette).

[0009] Thus, as waterways block 10 ₂ of the exhaust hole 14 cylinder waterway 10 disposed near, since the a-shaped upright U as, crankcase waterway 9 also corresponds to the shape It 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 The two water passages 9 _2a and 9 _2b which are raised and separated from each other with the island portion 27 interposed therebetween are almost sideways and have a “H” shape, and have two water passages 9 _2a and 9 _{2b. Are} adapted to correspond to the side passages 10 _2a and 10 _2b of the U-shaped channel block 10 ₂ , respectively, and the drainage passages 9 _2a and 9 _2b and the side passage 1
And 0 _2a, 10 _2b is an arrow B in FIG. 12, are adapted to assume a gentle curve shape as shown respectively by B, coolant from exiting waterway 9 _2a, 9 _2b is waterways block 10 ₂ The side roads 10 _2a and 10 _2b are sufficiently distributed.

[0010]

[SUMMARY OF THE INVENTION However, when a positional relationship that this way the water passage 9 _2a of the crankcase waterway 9 with respect to waterways block 10 ₂ of the bypass 10 _2a, 10 _2b, 9 _2b corresponding bypass one coolant water channel block 10 ₂
0 _2a , 10 _2b , which will be sufficiently distributed, but the hollow of the rib 24 of the exhaust hole 14 (hereinafter referred to as “rib channel”) 2.
No. 6 had a problem that the cooling liquid was not sufficiently distributed. Therefore, there is a problem that the cooling of the ribs 24 cannot be sufficiently performed because the cooling liquid does not easily flow through the rib water passages 26.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object to be solved is to make it easier to introduce a cooling liquid into a rib channel and to cool a rib of an exhaust hole. An object of the present invention is to provide a cylinder cooling structure of a two-stroke engine that can be sufficiently provided.

[0012]

SUMMARY OF THE INVENTION A cylinder cooling structure for a two-stroke engine according to the present invention solves the above-mentioned problems and is as follows. That is, the cylinder cooling structure of the two-stroke engine of the present invention
A crankcase water passage provided at an upper end of the crankcase, a cylinder water passage communicating with the crankcase water passage and being formed inside a cylinder integral with the crankcase and including a plurality of water passage blocks; A water jacket, which is a part of a circulation path for circulating a coolant between the radiator and the cylinder by a water pump, comprising a through hole provided in a gasket located between the cylinder and the cylinder. An exhaust hole is formed in the cylinder so as to intersect with the cylinder water passage and communicate with a hollow portion of the cylinder, and the periphery of the cylinder is surrounded by the cylinder water passage. A rib extending in the axial direction of the cylinder is formed at the center of the exhaust hole. Are formed so as to face the hollow portion, and the rib is formed with a rib channel extending in the longitudinal direction thereof and communicating with the cylinder channel, and a distal end of the crankcase channel is directed toward the rib channel. The cooling liquid from the radiator is guided to the rib channel by the provided 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. It is a guide channel. In addition, a water guide pipe that guides the coolant that has passed through the rib water channel to the radiator side may be arranged at the outlet side of the rib water channel that is a part of the circulation channel.

[0013]

Therefore, according to the cylinder cooling structure of the two-stroke engine of the present invention, the end of the crankcase waterway is
The cooling liquid from the radiator is formed by a guide groove having a tip directed to the rib channel, a through hole of the gasket provided corresponding to a tip of the guide groove, and a portion of the gasket other than the through hole. Is guided by the rib channel, the coolant entering the crankcase channel is advanced toward the rib channel by the guide channel.

[0014] Since a water conduit for guiding the coolant passing through the rib channel to the radiator side is disposed at the outlet side of the rib channel, which is a part of the circulation channel, the coolant discharged from the rib channel mainly enters the water conduit, and The cooling liquid that has entered the water pipe is guided toward the radiator side in the circulation path.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, a two-stroke engine cylinder cooling structure 1A according to the present invention will be described in detail with reference to the illustrated embodiments. It should be noted that the present invention is different from the prior art in that a guide means for guiding the cooling liquid to the rib channel is formed and a portion related thereto, so that the different portion will be described, and the other same portions will be the same. The description is omitted by attaching reference numerals. Therefore, with reference to FIGS. 10 to 12 used in the description of the related 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-stroke engine according to the present invention. FIG. 1 is an overall side view, and FIG. 2 is an arrow II direction in FIG. FIG. 3 is a sectional view taken along line III-III of FIG. 1, and 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, and FIG. FIG. 9 shows a third embodiment.

According to the cylinder cooling structure 1A of the two-stroke engine of the present invention, the water jacket 17A which is a part of the circulation path 5 for circulating the coolant between the radiator 2 and the cylinder 12 by the water pump 4 has:
A crankcase water passage 9A provided at an upper end 8Aa of the crankcase 8A is connected to a cylinder 12 which communicates with the crankcase water passage 9A and is integral with the crankcase 8A.
Is formed inside of and a plurality of waterways blocks 10A ₁ · 1
.. 0A ₂ ... 10A _X, and through holes 24A, 24 provided in a gasket 22A located between the crankcase 8A and the cylinder 12 to communicate the crankcase water passage 9A and the cylinder water passage 10A.
A. The through holes 24A, 24A may be combined into one larger track-shaped hole.

In the crankcase water passage 9A,
Flood channel 9 of crankcase channel 9 described in the section of the prior art.
_2a, crankcase waterway 9A is a portion corresponding to 9 _2b
In the portions 9A _2a and 9A _2b of the gasket 22A, the guide grooves 28, 28 whose tips are directed to the rib water channel 26 (the term “tip” means the end in the direction in which the coolant flows). Through holes 24A, 24A, and through holes 24A,
A guide water passage 30 is formed by a portion 22Aa of the gasket 22A other than 24A (see FIG. 7) and guides the cooling liquid from the radiator 2 to the rib water passage 26.

The guide groove 28 is formed in the island 27A,
As shown in FIG. 4, it comprises a flat portion 28a and a slope portion 28b. By appropriately changing the inclination angle of the slope 28b with respect to the plane 28a, the flow direction of the coolant toward the rib channel 26 is determined. Also,
The number of guide channels 30 need not be two, but may be one as shown in FIG. In this case, the flat 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 portion 28b with respect to the flat portion 28a is substantially 90 °. To do. As a result, the coolant flows toward the rib channel 26 from almost immediately below the rib channel 26. Also, needless to say, the gasket 22A has one through hole 24A.

The water conduit 32 is provided for facilitating the passage of the cooling liquid through the rib water channel to the outlet side of the rib water 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. Then, the end 32a on the rib channel side
Are separated from each other by an appropriate distance so as to face the outlet of the rib channel 26 on the outer periphery 34 of the cylinder barrel in contact with the upper wall surface of the cylinder 12 (the separation distance is indicated by a symbol S in this embodiment. Distance S is rib 24
The length is determined as appropriate depending on the degree of cooling. That is, the smaller the distance S, the larger the amount of the cooling liquid that passes through the ribs 24, so that the ribs 24 are cooled. ) It is straightened upward. Then, the anti-rib waterways end 32b, the opening 3 of the cylinder head 12 ₂ of the water outlet cap 36
6a. The water outlet cap 36 is connected to the radiator 2 via a radiator inlet hose 38.

As described above, according to the first embodiment of the cylinder cooling structure of the two-stroke engine of the present invention, since the guide water passage 30 is formed, the coolant entering the crankcase water passage 9A can be used as the guide water passage 30A. By the rib channel 2
Flow toward 6. Therefore, the rib channel 2
6 can be easily introduced, and the ribs 24 of the exhaust holes 14 can be sufficiently cooled.

The rib channel end 32a of the water guide pipe 32 is also provided.
Face the outlet of the rib channel 26, and the water outlet cap 36
The cooling water easily flows into the water guide pipe 32 and receives the suction of the water flow from the water pump 4 on the negative pressure side, so that the coolant flows vigorously through the water guide pipe 32. As a result, the flow of the cooling liquid in the rib water passage 26 is also increased, so that the cooling effect of the rib 24 can be enhanced.

Further, when the cooling effect of the ribs is enhanced, the cooling performance of the entire cylinder is also improved, so that the gap between the piston and the cylinder can be further reduced. Generation can be effectively prevented. Reference numeral 33 indicates the left and right cases 81, 8 of the crankcase 8.
r is the case mating surface.

(Embodiment 2) FIG. 8 shows an embodiment 2. The second embodiment is different from the first embodiment only in the part corresponding to the water pipe 32 and the parts related thereto. Therefore, the same reference numerals are given to the same parts as in the first embodiment, and the description will be omitted.

According to the cylinder cooling structure 1B of the two-stroke engine according to the second embodiment, the water pipe 32 of the first embodiment is used.
Is integrally or integrally connected to the rib 24 so that the length of the rib 24 becomes substantially longer. Therefore, the coolant 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 ribs 24 can be further enhanced. Further, the auxiliary hole 38 allows a new flow of the cooling liquid to be formed around the water guide tube 32 on the outer periphery 34 of the cylinder barrel, so that the cooling effect can be improved.

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 only relevant parts due to the difference. The same reference numerals are given to the portions and the description is omitted.

According to the cylinder cooling structure 1C of the two-stroke engine according to the third embodiment, the length of the water guide pipe 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. Reference numerals 42 and 44 indicate a union and a union pipe, respectively,
₅ is connected to the radiator 2.

Therefore, according to the cylinder cooling structure 1C of the two-stroke 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-stroke engine of the present invention, since the guide channel is formed, the coolant entering the crankcase channel can be advanced toward the rib channel. For this reason, it is possible to easily introduce the cooling liquid into the rib channel, and to sufficiently cool the rib of the exhaust hole. In addition, since a water guide pipe that guides the coolant that has passed through the rib water channel to the radiator side is arranged at the outlet side of the rib water channel that is a part of the circulation channel, the coolant that has flowed out of the rib water channel almost enters only the water pipe. Thus, the coolant entering the water pipe is guided toward the radiator in the circulation path. Therefore, the cooling effect of the rib can be further enhanced. Further, when the cooling effect of the ribs is enhanced, 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, generation of so-called cylinder noise when the piston moves in the cylinder can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is an overall side view.

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

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

FIG. 4 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 diagram showing a modification of FIG. 4;

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 longitudinal sectional view of a cylinder.

FIG. 12 is a sectional view taken along line XII-XII of FIG. 11;

[Explanation of symbols]

1A second stroke engine cylinder cooling structure 2 Radiator 4 water pump 5 circulation 8A crankcase 8Aa crankcase upper section 9A crankcase waterway 10 cylinder water passage 10 ₁ waterway block 10A ₂ 〃 10 _X 〃 10A cylinder block 12 cylinder 12a cylinder hollow Part 14 Exhaust hole 17 Water jacket 22A Gasket 22Aa Part of gasket 24 Rib 24A Gasket through hole 26 Rib channel 28 Guide groove 30 Guide channel

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F01P 3/02 F02F 1/10-1/22

Claims (2)

(57) [Claims] A crankcase water passage provided at an upper end of the crankcase, a cylinder water passage communicating with the crankcase water passage and being formed inside a cylinder integral with the crankcase and comprising a plurality of water passage blocks; A water jacket comprising a through hole provided in a gasket located between the crankcase and the cylinder, and being a part of a circulation path for circulating a coolant between the radiator and the cylinder by a water pump; In the cylinder cooling structure of a two-stroke engine provided with: an exhaust hole is formed in the cylinder so as to intersect with the cylinder water passage and communicate with a hollow portion of the cylinder, and the periphery is surrounded by the cylinder water passage. A centrally extending rib in the center of the cylinder Is formed so as to face the hollow portion, and the rib is formed with a rib channel which extends in the longitudinal direction and communicates with the cylinder channel, and a distal end of the crankcase channel has a tip directed toward the rib channel. The cooling liquid from the radiator is guided to the rib channel by the provided 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. A cylinder cooling structure for a two-stroke engine, which is a guide channel. 2. A cylinder cooling system for a two-stroke engine according to claim 1, wherein a water guide pipe for guiding a cooling liquid passing through the rib water channel to a radiator side is disposed at an outlet side of the rib water channel which is a part of the circulation channel. Construction.