JPS61205575A - Fuel feeder for motorcycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a fuel supply system for a motorcycle that improves running performance and reduces fuel vaporization.

(Prior art) In motorcycles, a fuel tank is mounted on a body frame on which an internal combustion engine is mounted, and fuel is supplied from the fuel tank to a carburetor provided in an intake system that communicates with the cylinders of the internal combustion engine. be.

Incidentally, the load on the fuel tank changes as the vehicle travels, and this load fluctuation causes a change in the ratio of the load shared between the front wheels and the rear wheels, and therefore, the driving performance also changes.

Moreover, since the fuel tank is located behind the carburetor, and this carburetor is located above the internal combustion engine, heat from the internal combustion engine is transferred to the fuel pipe that communicates the fuel tank and the internal combustion engine, resulting in excessive heat from the internal combustion engine. When the heat of the internal combustion engine is transferred, there is a risk that percolation, in which the fuel vaporizes, may occur, particularly in fuel piping where the heat capacity is small and fuel convection is difficult to occur.

(Problem to be Solved by the Invention) Therefore, it is desired that the fuel tank of a motorcycle be placed as close as possible to the center of gravity of the vehicle, including the rider, from the perspective of stabilizing running performance. There is a need for something that prevents percolation from occurring in small fuel pipes.

The present invention was made against this background, and aims to stabilize driving performance and effectively reduce vaporization of fuel due to heat of an internal combustion engine.

(Means for Solving the Problems) In order to solve the above problems, the present invention disposes the fuel tank above the internal combustion engine and immediately in front of the seat, and also moves the intake system above the cylinders of the internal combustion engine. The fuel tank is characterized in that it extends and communicates the fuel tank with the carburetor of the intake system located at the front via a fuel pipe.

(Function) In this invention, the fuel tank is placed above the internal combustion engine, just in front of the seat, and is close to the center of gravity of the vehicle. Therefore, due to load fluctuations in the fuel tank caused by driving, the front wheels and rear wheels are Changes in the ratio of shared loads can be suppressed as much as possible.

Therefore, the influence of the driving performance by the load fluctuation of the fuel tank is reduced, and the driving performance is stabilized.

In addition, the cylinders of the internal combustion engine are tilted so that the intake system extends from above the cylinders, and the fuel tank is placed at the rear of the intake system, thereby shortening the fuel piping that supplies fuel to the carburetor. Wind flows into the fuel tank, cooling the fuel pipes and reducing percolation, where fuel vaporizes due to heat.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

In the figure, reference numeral 1 denotes a body frame of a motorcycle, and a front fork 3 is rotatably supported by a head pipe 2 constituting the body frame 1 via a steering shaft (not shown). A front wheel (not shown) is supported at the lower end of the front fork 3, and a handle 4 is attached to the upper part.

A hollow box-shaped frame 5 is connected to the head pipe 2. This box-shaped frame 5 is made of aluminum and includes a joint 6, a main frame 7, and a rear frame 8.

The joint part 6 is formed by welding five aluminum plates into a box shape, and the joint part 6 is provided with a partition wall 6a inside for rigidity, and the head pipe 2 is welded to the front center part. The front end portion of the main frame portion 7 is connected to both left and right sides of the one box portion 6, and the rear end portion extends rearward and has a shape bifurcated from the joint portion 6.

This main frame section 7 is constructed by welding a divided body formed by bending two aluminum plates into a U-shaped cross section at the base surface.
b and sleeve 7C are provided to ensure rigidity. The rear end portion of the main frame 7 is welded to the carrier frame portion 8.

Further, brackets 9 are welded to both sides of the lower surface of the joint portion 6, and a pair of left and right down tubes 1 are attached to the brackets 9.
0 is removably connected to the front end thereof, and the rear end thereof is removably connected to the lower end of the rear frame portion 8.

In this way, the parallel multi-cylinder internal combustion engine 11 is mounted within the space formed by the head pipe 2, the box-shaped frame 5, and the down tube 10, and in this embodiment, a parallel four-cylinder four-stroke internal combustion engine is employed. Each cylinder 12 is inclined forward from the front upper part of the crankcase 13 along the down tube 10, and the crank case 13 extends rearward and is attached to the main frame section 7 and the rear catcher frame section 8 of the down tube 10. (゛ru.

The sprocket 14 of the internal combustion engine 11 is connected to a sprocket 17 of a rear wheel 16 via a chain 15, and the rear wheel 16 is swingably supported by the rear frame portion 8 via a rear arm 18.

An exhaust pipe 19 is connected to the front side of each cylinder 12, and this exhaust pipe 19 passes below the internal combustion engine 11 and extends rearward.

On the other hand, an intake passage 20 constituting an intake system is integrally formed above each cylinder 12.

This intake passage 20 extends straight upward.

A carburetor 21 is connected to this intake passage 20 via a connecting pipe 22, and an outside air intake pipe 23 is further connected to the carburetor 21.
is connected. This carburetor 21 and outside air intake pipe 23
extends upward from the cylinder 12, and the traveling wind passing over the cylinder 12 directly contacts and cools them.

The connecting pipe 22 absorbs vibrations caused by the driving of the internal combustion engine 11, reduces vibrations of the carburetor 21, and prevents heat conduction.

A fuel tank 24 is placed above the internal combustion engine 11 on the main frame portion 7 and a seat rail 25, and a seat 26 is placed on the seat rail 25 behind the fuel tank 24.

A fuel pump 28 forming a fuel system is accommodated in a recess 27 formed in the front wall of the fuel tank z4, and this fuel pump 28 is supported by a mounting band 29. The fuel pump 28 is mounted on the front wall of the fuel tank 24, at a position above the fuel tank 24 which is relatively easily exposed to direct wind from the vehicle. Therefore, due to the wind while driving, "fuel pump 2
The heat generation of the fuel pump 8 itself can be suppressed, and the pressure of the fuel applied to the fuel pump 28 can be made appropriate.

The suction side of the fuel pump 28 is connected to the bottom of the fuel tank 24 via a fuel pipe 30. On the other hand, fuel pump 2
The projecting side of 8 branches the fuel pipe 31 into two at the middle part, and further branches between the outer and inner carburetors 12 and communicates with the float chambers of each carburetor 21. are mixed and supplied to the combustion chamber.

An ignition electrical component 32 is disposed above the node 6, and the ignition electrical component 32 includes an ignition coil 33 and an ignition unit 34 such as an igniter.The ignition coil 33 has a high tension cord 35. The spark plug 36 is connected to the spark plug 36 via the spark plug 36.

The air-fuel mixture in the combustion chamber of the internal combustion engine 11 is rapidly combusted.

Next, the operation of this embodiment will be explained.

When the fuel pump 28 is operated, fuel is taken out from the fuel tank 24 via the fuel pipe 30, and this fuel is supplied to the float chamber of the carburetor 21 via the fuel pipe 31.

Then, by operating the throttle valve, the fuel and air are mixed at a predetermined ratio and are passed through the intake passage 20 to the internal combustion engine.
1 combustion chamber.

Incidentally, the load on the fuel tank 24 changes as the vehicle travels, and the fuel tank 24 is disposed immediately before the seat 26 and above the crankcase 13 of the internal combustion engine 11. In this way, since the fuel tank 24 is located as close as possible to the center of gravity of the vehicle, changes in the ratio of the load shared between the front wheels and the rear wheels due to changes in the load on the fuel tank 24 are reduced.

Therefore, changes in driving performance due to changes in the load on the fuel tank 24 can be suppressed as much as possible.

Furthermore, heat is generated by the operation of the internal combustion engine 11, and the heat is transferred to the fuel pipes 31, 30 of the fuel system or is affected by radiant heat.
Since the fuel pipes 31 and 1 are arranged close to each other and the fuel pipes 31 and 30 are shortened, the occurrence of cooperation is reduced.

Further, since the fuel pump 28, which is susceptible to association like the fuel pipes 31 and 30, is housed in the recess 27 of the fuel tank 24, the influence of heat is small.

Further, since the cylinder 12 of the internal combustion engine 11 is tilted forward and the intake passage 20 and the carburetor 21 protrude above the cylinder 12, the running wind flows over the cylinder 12, causing the intake passage 20 and the carburetor to Cool the container 21. Furthermore, this running wind flows at a high position from the road surface and contains little mud, dust, etc., and this running wind flows down along the front wall of the fuel tank 24 located at the rear. As a result, cooling of the fuel pipes 30, 31 and the fuel pump 28, which have small heat capacities, is facilitated, and the influence of heat from the internal combustion engine 11 can be minimized.

(Effects of the Invention) As described above, in this invention, since the fuel tank is placed above the internal combustion engine immediately before the seat and close to the center of gravity of the vehicle, load fluctuations in the fuel tank that occur as the vehicle runs This minimizes changes in the ratio of the load shared between the front wheels and the rear wheels, and stabilizes driving performance.

Furthermore, since the cylinders of the internal combustion engine are tilted so that the intake system extends from above the cylinders, and the fuel tank is disposed at the rear of the intake system, the fuel piping that supplies fuel to the carburetor can be shortened. Furthermore, the running air flows from above the internal combustion engine into the fuel tank and flows down along the front wall of the fuel tank to cool the fuel pipes, further reducing percolation where fuel vaporizes due to the heat of the internal combustion engine. can do.

[Brief explanation of drawings]

Figure 1 is a side view of a motorcycle to which this invention is applied;
The figure is a plan view of the main parts. l...Vehicle frame 2...Head pipe 5...
・Box-shaped frame 6... Joint part 7... Main frame part 8... Rear frame part lO... Down tube 11... Parallel multi-cylinder internal combustion engine

Claims (1)

[Claims] A fuel tank and a seat are mounted on a vehicle body frame on which the cylinders of an internal combustion engine are tilted forward, and fuel is supplied from the fuel tank to a carburetor installed in an intake system that communicates with the cylinders of the internal combustion engine. In a fuel supply system for a two-wheeled vehicle, a fuel tank is disposed above the internal combustion engine and immediately in front of the seat, the intake system is extended above the cylinders of the internal combustion engine, and the fuel tank is connected to the intake system located in front of the engine. A motorcycle fuel supply system that communicates with a carburetor via a fuel pipe.