JPS646331B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an intake system for a motorcycle equipped with a single-cylinder engine.

[Prior art]

In motorcycles that have a single-cylinder engine and are equipped with two intake ports on the left and right at the rear of the cylinder, these intake ports are connected to an air cleaner located at the rear via an intake pipe. It is becoming more and more like this. In this arrangement of the engine and air cleaner, there is no problem if there are no obstacles between the engine and the air cleaner, but if there are body structures such as the body frame or shock absorber intervening as obstacles. This causes a problem in that the intake pipe interferes with the vehicle body structure.

In particular, re-cylinder engines arranged in the above order,
If the three components, the vehicle body structure and the air cleaner, are lined up in the longitudinal direction at the center in the vehicle width direction, and the single-cylinder engine has two intake ports at the rear of the cylinder, the above problem becomes even more pronounced. Appears with age. In other words, in the above-mentioned single-cylinder engine, the intake ports are arranged close to each other on the left and right, so if the intake pipes connected to each intake port were to extend in parallel to the rear air cleaner, it would cause problems with the vehicle body structure. Interference becomes inevitable.

Furthermore, if the arrangement of the vehicle body structure is changed in order to solve the above problem, the weight balance near the center of gravity of the vehicle changes, which affects maneuverability and complicates the design.

[Purpose of the invention]

An object of the present invention is to solve the above-mentioned conventional problems and to interpose a vehicle body structure between an air cleaner and a single-cylinder engine having two intake ports on the left and right at a narrow interval at the rear of the cylinder, and to When arranging them side by side, the left and right intake pipes are provided independently so that they do not interfere with the vehicle body structure or affect maneuverability.
Furthermore, under these conditions, the engine performance was improved by allowing the air-fuel mixture to flow smoothly in both intake pipes and by preventing any misalignment in operation between the two carburetors installed in both intake pipes. The purpose of the present invention is to provide an intake device for a motorcycle.

[Structure of the invention]

An intake system for a motorcycle according to the present invention that achieves the above object includes a single-cylinder engine having two left and right intake ports at the rear of the cylinder, and one air cleaner arranged front and rear at the center in the width direction of the vehicle body. A vehicle body structure extending vertically is interposed between the cylinder engine and the air cleaner, and the two intake ports and one air cleaner are connected by independent left and right intake pipes. The air intake pipes are gradually expanded outward in the vehicle width direction toward the air cleaner, and are connected to the air cleaner after bypassing both outside sides of the vehicle body structure, and are connected to the left and right intake pipes located forward of the vehicle body structure. The present invention is characterized in that two carburetors are connected to each other, and an interlocking mechanism for driving the throttle valve of each carburetor is provided between the two carburetors.

〔Example〕

Hereinafter, the present invention will be explained with reference to embodiments shown in the drawings.

In the figure, 1 is a body frame that constitutes the body of a motorcycle, 1a is a main frame extending front and rear in the center in the width direction of the vehicle body, 1b is a down tube extending downward from the front side of main frame 1a, and 1c is a main frame. It is a center frame extending downward from the rear side of 1a. An engine 2 is mounted in a space surrounded by the main frame 1a, down tube 1b, and center frame 1c, and located at the center in the width direction of the vehicle body.

The engine 2 consists of a single cylinder, and two intake ports and two exhaust ports are provided on the left and right at the rear and front of the combustion chamber 2a in the upper part of the cylinder, respectively. and.
Intake ports provided with intake valves 6, 6 are connected to mutually independent carburetors 3, 3 via left and right independent intake pipes 5, 5, respectively, and intake ports extending rearward from these two carburetors 3, 3 are connected to mutually independent carburetors 3, 3, respectively. The pipes are distributed to both left and right sides of the center frame 1c, which is a vehicle body structure, and are connected to one air cleaner 4 disposed at the rear center in the width direction of the vehicle body. Here, when the left and right intake pipes 5, 5 are connected to the rear air cleaner 4, they each extend rearward from the two intake ports so as to gradually expand outward in the width direction of the vehicle body, and are further positioned at the center in the width direction of the vehicle body. The center frame 1c extends rearward along both sides of the center frame 1c.

The carburetor 3 is provided at a position in front of the center frame 1c with respect to the intake pipe 5 as described above. Reference numerals 8, 8 are throttle valves within the carburetors 3, 3, which are rotatably provided around rotating shafts 8a, 8a. The left and right rotational axes 8a, 8a are parallel to each other, and are provided perpendicular to the plane containing the intake passages 5a, 5a (ie, the paper plane of FIG. 3). Arms 9 and 10 are fixed to the upper ends of these rotating shafts 8a and 8a, respectively.
Rods 11 and 12 are rotatably connected to the other end of the arm 13, and the other ends of these rods 11 and 12 are rotatably connected to both ends of the arm 13, respectively.
The arm 13 is rotatable about a shaft 13a. A wire 14 is connected to the arm 10, and when the wire 14 is pulled in the direction of the arrow at a handle portion (not shown), the arm 10
0, 13, and 9 are rotated in the direction of the arrow via rods 12 and 11, thereby forming an interlocking mechanism in which the throttle valves 8 and 8 are simultaneously opened.

As described above, the intake system for a motorcycle according to the present invention has a single-cylinder engine 2 and an air cleaner 4 disposed front and back at the center position in the width direction of the vehicle body, and a space between the engine 2 and the air cleaner 4 located at the center of the vehicle body structure. The frame 1c is vertically penetrating, and the single cylinder engine 2 has two narrowly spaced intake ports on the left and right sides at the rear of the cylinder. However, the left and right independent intake pipes 5, 5 extending rearward from these intake ports are directed outward in the vehicle width direction, and are detoured along both left and right sides of the center frame 1c (vehicle body structure). Since they are extended, these intake pipes 5, 5 can be connected to the air cleaner 4 without interfering with the vehicle body structure.

In addition, this type of intake pipe connection does not require any changes in the layout of the vehicle body structure, so it does not change the weight balance near the vehicle's center of gravity, and therefore does not affect maneuverability. It has no effect.

In addition, an intake pipe 5 connected to the two intake ports,
5 gradually spreads outward in the width direction of the vehicle body so as not to provide much resistance, so that the air-fuel mixture flows smoothly, thereby ensuring that the air-fuel mixture is evenly supplied from the carburetor 3 to the engine 2. This makes it possible to improve engine output. Further, the air-fuel mixtures supplied to the combustion chamber 2a from these two intake pipes 5, 5 collide with each other to promote the generation of swirl. Therefore, combustion efficiency can be improved and engine performance can be improved.
Further, such a swirl promoting effect can be achieved by making the opening direction of the throttle valves 8, 8 rotate toward the engine 2 side, as shown by the arrows, as in the above embodiment. It can be made even higher.

Also, for the left and right intake pipes 5, 5, the carburetor 3,
3 is the center frame 1 of the vehicle body structure, respectively.
Since the carburetors 3 and 3 are disposed at a narrower position forward of point c, both the left and right carburetors 3 are brought close to each other, and the width of the vehicle body is not unnecessarily increased. Further, between the two carburetors 3, 3, which are close to each other in this way, the throttle valves 8, 8 of the two carburetors,
Since an interlocking mechanism is provided to drive 8, the interlocking mechanism can be shortened and rigidity and accuracy can be increased, allowing both valves to operate reliably as set and without any misalignment. It is possible to improve the performance of a single-cylinder engine.

〔Effect of the invention〕

As described above, the intake system for a motorcycle according to the present invention includes a single-cylinder engine having two left and right intake ports at the rear of the cylinder, and one air cleaner arranged front and rear at the center in the width direction of the vehicle body. A vehicle body structure extending in the vertical direction is interposed between the engine and the air cleaner, and the two intake ports and one air cleaner are connected by independent left and right intake pipes, and these left and right intake pipes are connected to the rear air cleaner. gradually expanding outward in the width direction of the vehicle body, bypassing both outer sides of the vehicle body structure, and then connecting to the air cleaner;
Further, a carburetor is connected to each of the left and right intake pipes located in front of the vehicle body structure, and an interlocking mechanism for driving a throttle valve of each carburetor is provided between both carburetors. It is.

Therefore, even in the case of a single-cylinder engine in which the two left and right intake ports are narrowly provided at the rear of the cylinder, the left and right independently provided intake pipes can be connected to the air cleaner without interfering with the vehicle body structure. In addition, in order to prevent interference with the car body structure,
There is no need to consider this change in the arrangement of the vehicle body structure, and there is no change in weight balance due to the change in arrangement, so maneuverability is not affected. Under these intake pipe piping conditions, the intake pipe gradually expands outward from the intake port in the width direction of the vehicle body, so the air-fuel mixture flows smoothly and is supplied to the carburetor and combustion chamber. This can contribute to improving the output of the engine.

In addition, carburetors are installed in both intake pipes, which are narrower in front of the car body structure, so there is no need to increase the car body width. Since this interlocking mechanism can be shortened and rigidity and accuracy can be increased, both carburetors can be operated according to the settings without any deviation, and in conjunction with the above-mentioned smooth air-fuel mixture flow, the single cylinder The output of the engine can be improved.

[Brief explanation of drawings]

Fig. 1 is a side view showing the main parts of a motorcycle equipped with an intake system according to an embodiment of the present invention, Fig. 2 is a plan view of the same, and Fig. 3 is a schematic enlarged view of the engine and carburetor. FIG. 1...Frame, 1a...Main frame, 1b...
...down tube, 1c...center frame,
2...engine, 3...carburizer, 4...air cleaner, 5...intake pipe, 5a...intake passage, 6...
Intake valve, 8... Throttle valve, 9, 10, 1
3... Arm, 11, 12... Rod, 14...
wire.

Claims (1)

[Claims] 1. A vehicle body structure in which a single-cylinder engine with two left and right intake ports at the rear of the cylinder and one air cleaner are arranged front and back at the center in the width direction of the vehicle body, and extend vertically between the single-cylinder engine and the air cleaner. The two intake ports and one air cleaner are connected by independent left and right intake pipes through the body, and the left and right intake pipes are gradually expanded outward in the width direction of the vehicle body toward the rear air cleaner. Both outside sides of the vehicle body structure are connected to the air cleaner after being bypassed, and carburetors are connected to the left and right intake pipes located forward of the vehicle body structure, and each carburetor is connected between the two carburetors. An intake device for a motorcycle, characterized by being provided with an interlocking mechanism for driving a throttle valve of the motorcycle.