JPS6229625B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a cylinder hole formed in a cylinder block, a piston slidably fitted into the cylinder hole, and a combustion chamber formed in a cylinder head above the piston, all of which have an oval cross section. This relates to a four-stroke internal combustion engine (hereinafter referred to as an elliptical engine) that has an oval or oval shape.

The present applicant has already proposed the four-stroke internal combustion engine which is compact overall and can obtain high output, but such an elliptical engine has a combustion chamber with a circular cross section compared to a normal internal combustion engine. Since the longitudinal axis is long, there is a technical issue in the combustion of the mixture within the combustion chamber.The engine burns the mixture more quickly and evenly, achieving high combustion efficiency comparable to that of the conventional engine. It is desirable that the

The present invention has been proposed in view of the above, and improves the arrangement, number, etc. of intake and exhaust ports opened into the combustion chamber, improves intake and exhaust efficiency, and improves the combustion effect of the air-fuel mixture within the combustion chamber. 〓〓〓〓〓〓〓〓〓〓〓
The object of the present invention is to provide a four-stroke internal combustion engine that satisfies the requirements and has a simple configuration.

In order to achieve the above object, the present invention includes a cylinder block having a cylinder hole into which a piston is slidably fitted, and a cylinder head which is polymerically bonded to the cylinder block and forms a combustion chamber above the piston. , a four-stroke internal combustion engine comprising: a crankcase which is polymerized and bonded below the cylinder block and rotatably supports a crankshaft which is connected to the piston via a connecting rod; and the cross-sectional shape of the combustion chamber is formed into an oval or elliptical shape, and one half of the combustion chamber wall in the longitudinal direction of the combustion chamber cross section has a plurality of pieces arranged in parallel with each other along the longitudinal direction. An intake valve port is opened in the other half, and a plurality of exhaust valve ports are opened in parallel with each other along the longitudinal direction in the other half, and the outer ends of the cylinder head are respectively opened in the upper surface of the head. and a main intake port and a main exhaust port extending linearly, and a plurality of ports equally branched from the inner ends of the main intake port and the main exhaust port and communicating with the intake valve port and the exhaust valve port, respectively. a plurality of intake valves and exhaust valves provided in the cylinder head to open and close the intake valve port and the exhaust valve port, respectively; and the main intake port and the main exhaust port. Both are arranged substantially radially from a point on a plane passing through the longitudinal center line of the cylinder hole and along the crankshaft axis, and substantially along the longitudinal direction of the cross section of the combustion chamber.

A first embodiment of the present invention will be described below with reference to FIGS. 1 to 6. This embodiment is a four-cylinder four-cycle internal combustion engine, and the engine body has a cylinder head 2 superimposed on the upper part of a cylinder block 1, and a crankcase 3 superposed on the lower part thereof, and these three parts are tightened. It is constructed by being tied together with a connecting bolt such as a bolt.

As clearly shown in FIG. 2, the cylinder block 1 has four cylinder holes 4, 4, . The center lines l-l along the longitudinal direction are parallel to each other and the cylinder block 1
, i.e., perpendicular to the axis of the crankshaft 10 when viewed from above. A piston 5 having an oval or oval cross section is slidably fitted into each of the four cylinder holes 4, 4, and a small end of a connecting rod 6 is fitted into each of these pistons 5. The connecting rods 7 are connected via a piston pin 9, and the large end 8 of the connecting rod 6 is connected to a crank pin 11 of a crankshaft 10 rotatably mounted on the crank case 3. There is.

The cylinder head 2 has a combustion chamber 12 having an oval or elliptical cross section and a substantially arcuate vertical cross section perpendicular to the rotational axis of the crankshaft 10.
is formed. In one half of the combustion chamber 12 wall in the longitudinal direction of the cross section of the combustion chamber (the right half in FIG. 1), four intake valve ports 13, 13, . In the other half (the left half in FIG. 1), four exhaust valve ports 14, 14, . . . are opened at the intersections of two parallel lines perpendicular to each other. The four intake valves 13, 13... and the exhaust valve ports 14, 14...
are arranged symmetrically with respect to the centerline s--s along the direction perpendicular to the longitudinal direction of the cross section of the combustion chamber 12.

The four intake valve ports 13, 13, . Intake port 15 _1,1
52 , ₁₅₃ and ₁₅₄ are in communication with each other, and these intake ports ₁₅₁ to ₁₅₄ are connected to the cylinder head 2.
The main intake ports 16 are formed in a straight line and are evenly branched from the inner end thereof.

Similarly, the four exhaust valve ports 14, 14
... have four exhaust ports 17 ₁ , 17 2 , and 17 , two inner rows near the center of the combustion chamber 12 and _two outer rows near the outside of the chamber 12 .
₃ , 17 _{and 4} are communicated with each other, and these exhaust ports 17
₁ to ₁₇₄ are equally branched from the inner end of one main exhaust port 18 formed linearly in the cylinder head 2.

The one main intake port 16 and the main exhaust port 1
8 is inclined outward in the longitudinal direction of the cross section of the combustion chamber 12 with respect to the longitudinal axis LL of the cylinder hole 4;
They are arranged in a V-shape with each other, and each outer end thereof opens at the upper surface of the cylinder head 2.

The outer end of the main intake port 16 is connected to the carburetor 19.
The outer end of the main exhaust port 18 is communicated with an exhaust pipe 20.

The cylinder head 2 has the four intake valve ports 1
Four intake valves 21 ₁ , 2 that open and close 3, 13...
1 ₂ , 21 ₃ , and 21 ₄ are fitted in such a way that they can be raised and lowered, and these intake valves 21 ₁ to 21 ₄ are aligned with the longitudinal axis L of the cylinder hole 4 so as to surround the main intake port 16 .
The cross section of the combustion chamber 12 is inclined outward in the longitudinal direction with respect to L, and the two intake valves 21 ₁ , 21 ₂ in the inner row near the center of the combustion chamber 12 are closer to each other than the main intake port 16 . Two intake valves 21 ₃ , 21 ₄ of the outer row on the inside and outside the combustion chamber 12
is located outside the main intake port 16, and the intake valve 2
1 ₁ , 21 ₂ , main intake port 16 and intake valve 2
Each of the axes 1 ₃ , 21 ₄ passes through the longitudinal axis LL of the cylinder hole 4 and extends approximately radially from a point O on a plane along the axis of the crankshaft 10, and approximately along the longitudinal direction of the cross section of the combustion chamber 12. It is arranged like this.
The inner and outer rows of intake valves 21 ₁ , 21 ₂ ,
Suction cam shafts 22 and 23 are rotatably mounted on the cylinder head 2 on the _{21 3} and 21 ₄ , respectively.
are arranged in the same direction as the crankshaft 10, and the cams 24, 24... on the intake camshafts 22, 23 are
The intake valve 21 ₁ ,
21 ₂ , 21 ₃ , 21 ₄ . Furthermore, a valve seat 27 is fitted onto the upper end of each of the intake valves 21 ₁ , 21 ₂ , 21 ₃ , 21 ₄ via a connector 26 , and the valve seat 27 and the valve seat surface 28 formed on the cylinder head 2 Valve springs 29 and 30 are interposed between them.

Furthermore, the cylinder head 2 has four exhaust valves 31 that open and close the four exhaust valve ports 14, 14...
₁ , 31 ₂ , 31 ₃ , 31 ₄ are fitted so as to be able to move up and down, and these exhaust valves 31 ₁ , 31 ₂ , 31 ₃ , 3
1 ₄ is inclined outward in the longitudinal direction of the cross section of the combustion chamber 12 with respect to the longitudinal axis LL of the cylinder hole 4 so as to surround the main exhaust port 18 , and a portion 1 4 is inclined toward the outside in the longitudinal direction of the cross section of the combustion chamber 12 so as to surround the main exhaust port 18 . Two exhaust valves 31 ₁ , 31 ₂ in an inner row are located inside the main exhaust port 18 , and two exhaust valves 31 ₃ , 31 ₄ in an outer row located outside the combustion chamber 12 are located inside the main exhaust port 18 . The axes of the exhaust valves 31 ₁ , 31 ₂ , the main exhaust port 18 , and the exhaust valves 31 ₃ , 31 ₄ pass through the longitudinal axis LL of the cylinder hole 4 and along the axis of the crankshaft 10 . They are disposed approximately radially from a point O on the plane and approximately along the longitudinal direction of the cross section of the combustion chamber 12 . Above the inner and outer rows of exhaust valves 31 ₁ , 31 ₂ and 31 ₃ , 31 ₄ , exhaust valve camshafts 32 and 33, which are rotatably mounted on the cylinder head 2, are connected to the crankshaft 10.
are arranged in the same direction as the exhaust valve camshafts 32, 3.
The cams _{34 , 34 ,} . Further, a valve seat 37 is fitted to the upper end of each of the exhaust valves 31 ₁ , 31 ₂ , 31 ₃ , 31 ₄ via a connector 36 , and a gap between the valve seat 37 and a valve seat surface 38 formed on the cylinder head 2 is provided. Valve springs 39, 40 are interposed therein.

The inner row intake valves 21 ₁ , 21 ₂ , the main intake port 16 and the outer row intake valves 21 ₃ ,
21 ₄ and the inner row exhaust valves 31 ₁ , 31 ₂ ,
Main exhaust port 18 and outer row exhaust valve 31 ₃ ,
₃₁₄ is arranged symmetrically with respect to the longitudinal axis LL of the cylinder bore 4.

As is clear from FIG. 1, the inner and outer rows of intake valves 21 ₁ , 21 ₂ and 21 ₃ , 21
₄ , and the longitudinal center lines Ii-Ii and Io-Io of the inner and outer rows of exhaust valves 31 ₁ , 31 ₂ and 31
The vertical center lines Ei-Ei and Eo-Eo _{of 3,314} are
Both of them extend substantially radially at equal intervals from a point O on a plane passing through the longitudinal axis LL of the cylinder hole 4 and along the axis of the crankshaft 10, and two intake camshafts 22, 23. And the rotation centers a, b, c, d of the two exhaust valve camshafts 32, 33 are the vertical center lines Ii-Ii, Io-Io, of the intake valves 21 ₁ to 21 ₄ and the exhaust valves 31 to 31 ₄ , and Ei―Ei, Eo―Eo
The rotation centers a, b, c, and d are located at the intersections of the circular arc CC drawn with the one point O as the center, and the intervals on the circular arc CC are equal. On the intake valve camshafts 22, 23 and the exhaust valve camshafts 32, 33, as shown in FIG.
42, 43, 44 are fixed, and these gears 41
~44 are meshed sequentially, and they are idle gears 4
5 and 46, the intake valve camshafts 22 and 23 and the exhaust valve camshafts 32 and 33 are driven to rotate at 1/2 of the rotation speed of the crankshaft 10. .

〓〓〓〓〓
At the center of the oval or elliptical combustion chamber 12, that is, at the intersection of the center line l-l and ss,
A spark plug 48 is provided.

Next, the operation of the first embodiment of the present invention will be explained. Now that the engine is being operated, during the intake stroke in which the piston 5 descends, the four intake valves 21 ₁ , 21 ₂ are rotated by the rotation of the intake valve camshafts 22 and 23. ,21 ₃ ,21
₄ are both opened, and the air-fuel mixture adjusted to an appropriate air-fuel ratio by the carburetor 19 is fed to one main intake port 1.
6 to four intake ports 15 ₁ to 15 ₄ and flows into the combustion chamber 12 . In this case, the four intake valves 21 ₁ to 21 ₄ surround the main intake port 16 and are substantially concentrated at one point on the longitudinal axis LL of the cylinder hole 4.
The air-fuel mixture is evenly distributed to the four intake ports 15 ₁ to 15 ₄ and flows into the combustion chamber 12 . The air-fuel mixture that has entered the combustion chamber 12 flows from one end in the longitudinal direction of the cross section of the chamber 12 to the center thereof, and near the end of the compression stroke in which the piston 5 rises, the ignition plug 4 is struck.
The combustion flame is quickly propagated in the longitudinal direction of the cross section of the combustion chamber 12, and the air-fuel mixture in the combustion chamber 12 is quickly and evenly combusted during the downward expansion stroke of the piston. During the upward exhaust stroke of the piston 5, the combustion gas also flows in the longitudinal direction of the cross section of the combustion chamber 12, passes through the four exhaust ports ₁₇₁ to ₁₇₄ , and is collected into one main exhaust port 18, from which the exhaust pipe 20 to the atmosphere. In this case, the combustion gas in the combustion chamber 12 is discharged through four exhaust ports 17 ₁ to 17 ₄ extending radially along the longitudinal direction of the cross section of the combustion chamber 12.
Since the air is exhausted through the ports, it can flow evenly to those ports to increase exhaust efficiency.

A second embodiment of the invention is shown in FIGS. 7 and 8. In this second embodiment, two intake valve ports 13, 13 and two exhaust valve ports 14, 14 are opened on the center line l-l along the longitudinal direction of the cross section of the combustion chamber 12. The two intake ports 15 ₁ ′, 15 ₃ ′ communicate with the main intake port 16 , and the exhaust valve ports 14 , 1 communicate with the main intake port 16 .
Two exhaust ports 17 ₁ ′, 17 communicated with 4
₃ ' communicates with one main exhaust port 18. Further, the ignition plug 48 is provided so as to be biased to one side on the center line ss along the direction orthogonal to the longitudinal direction of the cross section of the combustion chamber 12. This second embodiment also has the same effect as the first embodiment. In this second embodiment, the combustion chamber 12 can be formed more compactly.

As described above, according to the present invention, the cylinder hole 4,
The cross-sectional shapes of the piston 5 and the combustion chamber 12 are both oval or elliptical, and on one half of the combustion chamber 12 wall in the longitudinal direction of the combustion chamber cross section, they are arranged parallel to each other along the longitudinal direction. A plurality of intake valve ports 13, 13 are provided in the other half, and a plurality of exhaust valve ports 1 are arranged in parallel with each other along the longitudinal direction.
The cylinder head 2 has a main intake port 16 and a main exhaust port 18 each having an open outer end on the top surface of the head 2 and extending linearly, and a main intake port 16 and a main exhaust port 18, respectively. 16
and a plurality of intake ports 15 ₁ , 15 ₃ ; 15 ₂ , 15 4 which are equally branched from the inner end of the main exhaust port 18 and communicate with the intake valve ports 13 , 13 and the exhaust valve ports 14 , 14 _, respectively. ;15
₁ ′, 15 ₃ ′ and exhaust port 17 ₁ , 17 ₃ ; 1
7 ₂ , 17 ₄ ; 17 ₁ ′, 17 ₃ ′, and a plurality of intake valves 21 provided in the cylinder head 2 to open and close the intake valve ports 13, 13 and the exhaust valve ports 14, 14, respectively. ₁ ,21 ₃ ;21 ₂ ,2
1 ₄ and exhaust valves 31 ₁ , 31 ₃ ; 31 ₂ , 31
₄ , the main intake port 16 and the main exhaust port 18 are arranged approximately radially from a point O on a plane passing through the longitudinal axis LL of the cylinder hole 4 and along the axis of the crankshaft 10, and furthermore, the combustion chamber 12 Since the main intake port 16 is arranged substantially along the longitudinal direction of the cross section of the main intake port 16, the plurality of intake ports 15 ₁ , 15 ₃ ;
5 ₂ , 15 ₄ ; 15 ₁ ', 15 ₃ ' to the plurality of intake valve ports 13, 13 can be made approximately equal, and each intake valve 21 ₁ , 21 ₃ ; 21
₂ , 21 ₄ ; 21 ₁ ′, 21 ₃ ′, the air-fuel mixture is distributed almost equally to the main intake port 16 and the number of intake valves is plural, so that intake resistance is reduced. Together with the reduced effect, this can greatly contribute to improving the intake efficiency of the engine. Moreover, a plurality of exhaust ports 17 ₁ , 17 ₃ ; 17 ₂ , 17 ₄ ; 17 ₁ ′, 1
7 ₃ ′ to the main exhaust port 18 can be made approximately equal, and each exhaust valve 31 ₁ , 3
1 ₃ ; 31 ₂ , 31 ₄ ; 31 ₁ ′, 31 ₃ ′. Therefore, the main exhaust port 18 is
The linear shape and the plurality of exhaust valves reduce exhaust resistance, which together can greatly contribute to improving the exhaust efficiency of the engine.

Further, the mixtures flowing into the combustion chamber 12 through the plurality of intake valve ports 13, 13 flow from one end to the center along the longitudinal direction of the cross section of the combustion chamber 12, which has an oval or elliptical cross section. The combustion flame ignited by the spark ignited by the spark plug also propagates along the longitudinal direction of the cross section of the combustion chamber 12.
The air-fuel mixture in the combustion chamber 12 can be quickly combusted, and the combustion gas can also flow to the other end in the longitudinal direction of the cross section of the combustion chamber 12 and smoothly flow out radially from the plurality of exhaust valve ports 14, 14. Therefore, even if the cross section of the combustion chamber 12 is oval or elliptical, the combustion efficiency of the air-fuel mixture within the chamber 12 can be significantly improved.

Furthermore, the main intake port 16 and the main exhaust port 18, each of which has an open outer end on the top surface of the cylinder head 2, are
The ports themselves are formed in a straight line, and a plurality of intake valves 21 ₁ , 21 ₃ ; 21 ₂ , 2 are arranged radially along the longitudinal direction of the cross section of the combustion chamber 12 .
1 ₄ ; 21 ₁ ', 21 ₃ ' and exhaust valves 31 ₁ , 31
₃ ; 31 ₂ , 31 ₄ ; 31 ₁ ′, and 31 ₃ ′, the outer end opening positions of both ports 16 and 18 are arranged as far as possible in the longitudinal direction of the cross section of the combustion chamber 12. Therefore, the amount of protrusion of the intake and exhaust system components connected to the outer ends of the ports 16 and 18 to the side of the cylinder head 2 can be reduced as much as possible. This is advantageous in making the engine more compact in the cross-sectional and longitudinal direction of the combustion chamber 12.

[Brief explanation of the drawing]

1 to 6 show a first embodiment of the present invention.
The figure is a vertical cross-sectional view along the line of Figure 2, Figure 2 is a cross-sectional view along the line of Figure 3, Figure 3 is a longitudinal cross-sectional view along the line of Figure 2, and Figure 4 is a longitudinal cross-sectional view along the line of Figure 1. FIG. 5 is a partial cross-sectional view along the line of FIG. 1, FIG. 6 is a front view showing the transmission gear system of the intake camshaft and exhaust camshaft, and FIGS. A second embodiment is shown, and FIG. 7 is the same cross-sectional view as FIG. 2, and FIG. 8 is a partial sectional view taken along the line of FIG. 7. 1... Cylinder block, 2... Cylinder head, 3... Crank case, 4... Cylinder hole,
5...Piston, 6...Connecting rod,
10...Crankshaft, 12...Combustion chamber, 13...
Intake valve port, 14...Exhaust valve port, 15 ₁ to 15 ₄ ...
...Intake port, 16...Main exhaust port, 17 ₁ ~
17 ₄ ...Exhaust port, 18...Main exhaust port,
21 ₁ to 21 ₄ ... Intake valve, 31 ₁ to 31 ₄ ...
exhaust valve. 〓〓〓〓〓

Claims (1)

[Claims] 1. A cylinder block 1 having a cylinder hole 4 into which a piston 5 is slidably fitted, a cylinder head 2 which is bonded to the cylinder block 1 and forms a combustion chamber 12 above the piston 5, and the cylinder block 1. In a four-cycle internal combustion engine, the four-cycle internal combustion engine is equipped with a crankcase 3 which is overlappingly connected to the bottom of the cylinder hole 4 and rotatably supports a crankshaft 10 which is connected to the piston 5 via a connecting rod 6. , the cross-sectional shapes of the piston 5 and the combustion chamber 12 are both oval or elliptical, and one half of the wall of the combustion chamber 12 in the longitudinal direction of the cross-section of the combustion chamber 12 has a groove along the longitudinal direction. A plurality of intake valve ports 13, 13 arranged in parallel with each other,
The other half has a plurality of exhaust valve ports 14, 14 opened in parallel with each other along the longitudinal direction, and the cylinder head 2 has outer ends opened at the upper surface of the head 2. In addition, each main intake port 16 and main exhaust port 18 extend linearly, and the inner ends of the main intake port 16 and the main exhaust port 18 are equally branched to form the intake valve ports 13, 13 and the exhaust valve. Mouth 14,1
Each plurality of intake ports 15 communicate with each of 4.
₁ , 15 ₃ ; 15 ₂ , 15 ₄ ; 15 ₁ ', 15 ₃ ' and exhaust port 17 ₁ , 17 ₃ ; 17 ₂ , 17
₄ ; 17 ₁ ′, 17 ₃ ′, and the intake valve port 1
A plurality of intake valves 21 ₁ , 21 ₃ ; 21 ₂ , 21 ₄ and exhaust valves 31 ₁ , 31 ₃ ; 31 ₂ are provided in the cylinder head 2 to open and close the exhaust valve ports 14 and 14, respectively. ,31 ₄ and
Both the main intake port 16 and the main exhaust port 18 are arranged approximately radially from a point O on a plane passing through the longitudinal axis LL of the cylinder hole 4 and along the axis of the crankshaft 10, and in a cross section of the combustion chamber 12. A four-stroke internal combustion engine that is arranged approximately along the longitudinal direction.