JP3170934B2 - Two-cycle V-type engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-cycle V with equalized intake performance between two cylinder assemblies.
Type engine.

[0002]

2. Description of the Related Art FIG. 3 is a right side view showing an example of a two-cycle V-type engine mounted on a motorcycle or the like.
The two cylinder assemblies 101 and 102 included in the two-cycle V-type engine 100 are respectively installed on the upper part and the front part of a crankcase 103 so as to sandwich an axis O of a crankshaft (not shown). 101 is arranged on the left side, and the cylinder assembly 102 is arranged on the right side. FIG. 4 is a single view of the crankcase 103 as viewed from the arrow IV in FIG.

An intake passage 104 for the cylinder assembly 101 and an intake passage 105 for the cylinder assembly 102 are provided in the crankcase 103. In the intake passages 104 and 105, reed valves 106 and 107 are provided, respectively. Are installed, and the intake passages 104 and 10
The carburetors 110 and 111 are connected to the openings 5 through intake manifolds 108 and 109, respectively.

[0004] The carburetors 110 and 111 generate a mixture of air and fuel, and the mixture is mixed with intake manifolds 108 and 109 and intake passages 104 and 1.
After being sucked into the crankcase 103 through the cylinder 05, the compressed air is primarily compressed in the crankcase 103, and then supplied to the cylinder assemblies 101 and 102.

[0005]

By the way, in such a two-cycle V-type engine 100, the reed valve 107 for the right cylinder assembly 102 tends to interfere with the left cylinder assembly 101 due to the layout. To prevent this, the pitch P between the cylinder assemblies 101 and 102 is increased, or the reed valve 107 is installed vertically as shown in FIGS. 3 and 4, and the intake passage 105 is formed in a substantially S-shape. Thus, it is conceivable to avoid interference between the reed valve 107 and the cylinder assembly 101.

However, in the former case, the engine width becomes large, which is not preferable. In the latter case, the degree of freedom of the engine layout is impaired and the intake passage 10
5 becomes longer than necessary, the length of the intake passage differs greatly between the left and right cylinder assemblies 101 and 102. At the same time, the flow of the air-fuel mixture in the intake passage 105 is not straight, The intake performance may be uneven between the assemblies 101 and 102.

In addition, since the internal volume of the intake passage 105 is increased, the primary compression pressure of the air-fuel mixture in the crankcase 103 is reduced, the output of the cylinder assembly 102 is reduced, and the responsiveness of the engine speed to throttle operation is reduced. There was a problem such as worsening.

[0008] In addition, when the intake performance and output characteristics between the left and right cylinder assemblies 101 and 102 become uneven as described above, a number of experiments and trial productions must be performed to determine conditions, and engine development is performed. Evils such as a very long period occur.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to make the intake performance of two cylinder assemblies uniform without increasing the width of the engine and without impairing the flexibility of the engine layout. It is an object of the present invention to provide a two-cycle V-type engine capable of performing the following.

[0010]

In order to achieve the above object, a two-cycle V-type engine according to the present invention has two cylinder assemblies installed in a V-shape in a crankcase, and supplies an air-fuel mixture to each of the cylinder assemblies. Do 2
In a two-stroke V-type engine in which two intake passages are provided in a crankcase, at least one of the two cylinder assemblies is installed in the crankcase in a form rotated by a predetermined angle about a cylinder axis. The center line of the intake passage extends substantially in parallel with the rotation direction of the cylinder assembly, and extends in a direction away from the other cylinder assembly.

Further, the shape and the length of the two intake passages are substantially the same.

[0012]

According to the two-stroke V-type engine having the above-described structure, the intake passage of the cylinder assembly rotated by a predetermined angle about the cylinder axis extends straight in a direction away from the other cylinder assembly. The possibility that the reed valve incorporated in the passage interferes with the other cylinder assembly is eliminated. For this reason, without increasing the pitch between the two cylinder assemblies, without being restricted by layout restrictions such as installing the reed valve vertically and forming the intake passage in an S-shape.
It is possible to equalize the intake performance of the two cylinder assemblies.

Further, since the two intake passages have substantially the same shape and length, the flow of the air-fuel mixture supplied from the carburetor is uniform, and the intake performance between the two cylinder assemblies is further equalized.

[0014]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a two-cycle V to which the present invention is applied.
It is a right view which shows an example of a type | mold engine. This two-cycle V-type engine 1 has two cylinder assemblies 2
3 is installed in the crankcase 4 in a V-shape with the axis O of a crankshaft (not shown) interposed therebetween. For example, the cylinder assembly 2 is disposed on the left side, and the cylinder assembly 3 is disposed on the right side. FIG. 2 is a single view of the crankcase 4 as viewed from the direction of the arrow II in FIG.

As shown in FIGS. 1 and 2, cylinder openings 5 and 6 are formed in the crankcase 4, and the cylinder assemblies 2 and 3 are fixed to the cylinder openings 5 and 6, respectively. . At this time, the cylinder assemblies 2 and 3 are fixed to the cylinder openings 5 and 6 by four bolts (not shown), and the bolts are bolt holes 7 and 8 formed around the cylinder openings 5 and 6.
Is concluded.

The crankcase 4 has two intake passages 9, 1 for supplying an air-fuel mixture to the two cylinder assemblies 2, 3.
The reed valves 11 and 12 are built in the respective intake passages 9 and 10, and the intake passages 9 and 10 are provided.
Carburetors 15 and 16 are connected to the openings through intake manifolds 13 and 14, respectively.

As shown in FIG. 2, the cylinder opening 6
The four bolt holes 8 formed around the cylinder opening 6 are formed in the crankcase 4 at an angle θ with respect to the center line 2a of the two-cycle V-type engine 1. For this reason, the cylinder assembly 3 is fixed to the crankcase 4 so as to rotate by the angle θ about the cylinder shaft 3a.

The passage center line 1 of the intake passage 10
0a extends substantially in a straight line in parallel with the direction of the angle θ and in a direction away from the other cylinder assembly 2. The shapes and lengths of the two intake passages 9 and 10 are substantially the same.

With this configuration, even if the intake passage 10 is short and straight, the reed valve 12
Does not interfere with the other cylinder assembly 2. For this reason, without increasing the pitch P between the two cylinder assemblies 2 and 3, the reed valve 12
The intake performance of the two cylinder assemblies 2 and 3 can be made uniform without being restricted by a layout such as installing the cylinder vertically or forming the intake passage 10 in an S-shape.

Further, since the length of the intake passage 10 can be minimized, the internal volume of the intake passage 10 does not expand. Therefore, the primary compression pressure of the air-fuel mixture in the crankcase 4 is kept uniform between the cylinder assembly 2 side and the cylinder assembly 3 side, and the output characteristics become uniform. Further, there is no possibility that a problem such as deterioration of responsiveness of the engine speed to the throttle operation occurs.

As described above, since the intake performance and output characteristics are equal between the left and right cylinder assemblies 2 and 3, there is no need to perform many experiments and trial productions for determining the conditions, and the engine development period is extremely short. Is shortened to

Further, if the present invention is applied, the pitch P between the cylinder assemblies 2 and 3 of the two-cycle V-type engine 1 can be reduced, and the angle between the cylinder assemblies 2 and 3 can be reduced. The two-cycle V-type engine 1 can be made compact.

In the present embodiment, the cylinder assembly 3 is installed on the crankcase in such a manner that only the cylinder assembly 3 is rotated, but the cylinder assembly 2 may also be installed in the crankcase 4 by rotating. In this case, the passage center line 9 a of the intake passage 9 is inclined in a direction away from the cylinder assembly 3.

[0025]

As described above, in the two-stroke V-type engine according to the present invention, two cylinder assemblies are installed in the crankcase in a V-shape, and two intake passages for supplying a mixture to each of the cylinder assemblies are provided. In a two-cycle V-type engine provided in the crankcase,
At least one of the two cylinder assemblies is installed in a crankcase in a form rotated by a predetermined angle about the cylinder axis, and the center line of the intake passage of the cylinder assembly is set in parallel with the rotation direction of the cylinder assembly. It is characterized in that it extends substantially straight in a direction away from the other cylinder assembly.

Accordingly, there is no possibility that the reed valve built in the intake passage interferes with the other cylinder assembly. For this reason, the two cylinder assemblies can be used without increasing the pitch between the two cylinder assemblies and without being restricted by a layout such as a vertically installed reed valve or an S-shaped intake passage. It is possible to equalize the intake performance of the assembly.

Further, the two-stroke V-type engine according to the present invention is characterized in that the shape and length of the two intake passages are substantially the same, so that the flow of the air-fuel mixture supplied from the carburetor And the intake performance between the two cylinder assemblies is further equalized.

[Brief description of the drawings]

FIG. 1 is a right side view showing an example of a two-cycle V-type engine to which the present invention is applied.

FIG. 2 is a view showing one embodiment of the present invention, and is a single view of the crankcase as viewed in the direction of arrow II in FIG. 1;

FIG. 3 is a right side view of a two-cycle V-type engine showing a conventional technique.

FIG. 4 is a single view of the crankcase as viewed from an arrow IV in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 2 cycle V-type engine 2, 3 cylinder assembly 4 Crank case 5, 6 Cylinder opening 9, 10 Intake passage 11, 12 Reed valve 13, 14 Intake manifold 15, 16 Carburetor 2a Center line of 2 cycle V-type engine 3a cylinder Shaft 10a Passage center line of the intake passage θ Angle at which the cylinder assembly is rotated P Pitch between the two cylinder assemblies

Claims (2)

(57) [Claims] 1. A two-cycle V-type engine in which two cylinder assemblies are installed in a crankcase in a V-shape, and two intake passages for supplying an air-fuel mixture to each of the cylinder assemblies are provided in the crankcase. At least one of the cylinder assemblies is installed in the crankcase in a form rotated by a predetermined angle about the cylinder axis, and the center line of the intake passage of the cylinder assembly is substantially straight in parallel with the rotation direction of the cylinder assembly. A two-stroke V-type engine extending in a direction away from the other cylinder assembly. 2. The two-stroke V-type engine according to claim 1, wherein the two intake passages have substantially the same shape and length.