JP2500963Y2 - Fuel supply system for 2-cycle engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to improvement of a fuel supply system for a two-cycle engine.

[Conventional technology]

The two-cycle engine uses a mixed oil in which lubricating oil is mixed in fuel and lubricates each part of the engine with the lubricating oil mixed in the fuel. However, since it is troublesome to make a mixed oil, a separate refueling, which is equipped with an oil pump that interlocks with the engine to feed a small amount of lubricating oil and injects the lubricating oil into the crank chamber etc. separately from the fuel, has become widely used. There is. There is also a fuel pump and an oil pump that send fuel and lubricating oil to a carburetor and mix the fuel and lubricating oil in the float chamber of the carburetor. See, for example, JP-A-60-13911.

[Problems to be solved by the device]

An oil pump that injects a small amount of lubricating oil separately from fuel into the crank chamber, etc., causes insufficient mixing of fuel and lubricating oil, resulting in parts with good lubrication and parts that cannot be sufficiently lubricated. There is a lot of white smoke in the exhaust that flows into the exhaust pipe, there is a lot of carbon clogging such as muffler, and the consumption of lubricating oil is large. Further, the vaporizer that mixes the fuel and the lubricating oil has a disadvantage that it cannot stir and the lubricating oil is accumulated in the float chamber.

In view of this point, the present invention, in which a small amount of lubricating oil is discharged by an oil pump, is sent together with fuel to a fuel pump and agitated in the fuel pump, and this is sent to a carburetor to agitate the fuel and lubricating oil well. An object of the present invention is to obtain a fuel supply system for a two-cycle engine that can lubricate the engine with the mixed oil.

[Means for solving the problem]

In order to achieve the above object, the present invention has the following configuration.

That is, the present invention includes a crankshaft 1 extending in a substantially horizontal direction in a crankcase 6, and a driven gear 4 that meshes orthogonally with a drive gear 2 of the crankshaft 1, and extends in a substantially vertical direction and extends in the crankcase 6 Is rotatably driven by the pump shaft 3 which is axially supported by the pump shaft 3 and the outer periphery of the upper end portion of the pump shaft 3 which is disposed in an upwardly opened recess 6b formed in the upper wall 6a of the crankcase 6. A fuel pump 5 and an oil pump 8 mounted on the crankcase 6 so as to overlap the drive shaft core C of the fuel pump 5 on the upper part of the fuel pump 5, and a drive provided at the lower end of the oil pump 8. The shaft 9 is fitted into and engaged with the center of the upper end portion of the pump shaft 3 from above, so that the fuel pump 5 and the oil pump 8 are simultaneously operated by one pump shaft 3. A fuel supply device for a driven two-cycle engine, wherein a fuel inlet 13a at one end is integrally provided on the upper wall 6a of the crankcase 6 and the other end is made of the fuel. The introduction side fuel passage 13 communicated with the pump 5 is integrally formed, and the fuel introduction port 13
A hose 15 communicating with the fuel tank 14 is connected to a, and a hose 12 communicating with the oil tank 11 is connected to the inlet 10 of the oil pump 8, while an outlet 16 of the oil pump 8 is connected.
Is connected via a hose 17 to an oil introduction port 13b integrally formed on the upper wall 6a of the crankcase 6, which communicates with the introduction side fuel passage 13 on the downstream side of the fuel introduction port 13a, Further, inside the upper wall 6a of the crankcase 6, a discharge side fuel passage 18 for pumping the mixed oil of fuel and oil from the fuel pump 5 is provided, and a discharge port at the downstream end of the discharge side fuel passage 18 is provided. A fuel supply device for a two-cycle engine is characterized in that a hose 19 having one end connected to a carburetor 20 is connected to 18a.

[Action]

When the pump shaft 3 rotates due to the operation of the engine, the oil pump 8 discharges a small amount of lubricating oil from the oil tank 11 to the oil introduction port 13b.

On the other hand, the fuel pump 5 sucks the fuel from the fuel tank 14 through the hose 15 and the introduction side fuel passage 13. At this time, the lubricating oil that has entered the oil introduction port 13b from the oil pump 5 merges with the fuel flowing through the introduction side fuel passage 13 and is introduced into the fuel pump 5 together with the fuel. Fuel pump 5
Inside, the fuel and the lubricating oil are satisfactorily agitated by the rotation in the fuel pump 5, and then become mixed oil and are sent to the carburetor 20 via the outlet side fuel passage 18 and the hose 19. Therefore, the mixed oil that has been stirred well from the carburetor 20 is sent to the crank chamber, and each part of the engine can be evenly and uniformly lubricated. Therefore, it is possible to reduce the amount of lubricating oil mixed in, reduce the amount of lubricating oil consumed, and reduce white smoke and carbon clogging in the exhaust gas.

Further, since the fuel pump 5 is disposed in the upwardly opened concave portion 6b formed in the upper wall 6a of the crankcase 6, the pump case is eliminated as compared with the fuel pump housed in its own pump case. The number of parts can be reduced and the structure for sealing oil can be simplified.

Further, the fuel passage (the fuel introduction passage 13 and the fuel discharge passage 18) communicating with the fuel pump 5 and the introduction-side fuel passage
Since the oil inlet 13b communicating with 13 is formed integrally with the upper wall 6a of the crankcase 6, it is possible to reduce the number of members for joining the lubricating oil path and the fuel path, and at the same time, to reduce the crankcase 6 Since the piping structure of each hose is simplified around the upper wall 6a, the hoses do not intersect with each other.

Moreover, since the fuel pump 5 and the oil pump 8 are overlapped and driven by one pump shaft 3, the structure can be simplified.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The figure shows the case of a two-cycle engine mounted as power for a scooter.

The fuel supply system for a two-cycle engine according to the present embodiment includes a crankshaft 1 extending in a substantially horizontal direction in a crankcase 6, and a driven gear 4 that meshes with a drive gear 2 of the crankshaft 1 at right angles. Pump shaft 3 extending in the direction of the crankcase 6 and axially supported by the crankcase 6, and the outer circumference of the upper end of the pump shaft 3
Disposed in the upper open recess 6b formed in the upper wall 6a,
A fuel pump 5 that is rotationally driven by a pump shaft 3 and an oil pump 8 that is mounted on a crankcase 6 coaxially with a drive shaft center C of the fuel pump 5 are provided above the fuel pump 5. Then, the drive shaft 9 provided at the lower end of the oil pump 8 is fitted into and engaged with the center of the upper end of the pump shaft 3 from above, so that the fuel pump 5 and the oil pump 8 can be operated by one pump shaft 3. Driven at the same time.

The fuel pump 5 is a rotary type such as a trochoid pump having a case integrally provided with the crankcase 6, and connects the pump inner 7 to the pump shaft 3. The oil pump 8 is of a rotary plunger type, and the rotary shaft 9 is meshed with the tip of the pump shaft 3.

Inside the upper wall 6a of the crankcase 6, a fuel introduction port 13a at one end is integrally projectingly provided on the upper wall 6a, and an introduction side fuel passage 13 communicating with the fuel pump 5 at the other end is integrally formed. . A hose 15 communicating with the fuel tank 14 is connected to the fuel inlet 13a. The hose 12 communicating with the oil tank 11 is connected to the inlet 10 of the oil pump 8, while the outlet 16 of the oil pump 8 communicates with the introduction side fuel passage 13 on the downstream side of the fuel introduction port 13a. Upper wall 6a of case 6
It is connected via a hose 17 to an oil introducing port 13b which is integrally provided on the upper side. Further, inside the upper wall 6a of the crankcase 6, a discharge side fuel passage 18 for pumping the mixed oil of fuel and lubricating oil from the fuel pump 5 is provided, and a discharge port at the downstream end of the discharge side fuel passage 18 is provided. The other end of the hose 19 whose one end is connected to the vaporizer 20 is connected to 18a. In addition, vaporizer
20 is connected to the intake pipe 21 of the engine.

According to the present embodiment configured as described above, the lubricating oil discharged by the oil pump 8 is sucked into the fuel pump 5 together with the fuel, and is sufficiently agitated by the rotation of the inner 7 in the fuel pump 5 to obtain the fuel. A mixed oil of oil and lubricating oil can be sent to the carburetor 20 and sent to the crankcase of the engine. Therefore, each part of the engine can be evenly and uniformly lubricated. Therefore, the mixing ratio of the lubricating oil can be reduced, the consumption of the lubricating oil can be reduced, the exhaust gas can be reduced, and the muffler can be less clogged with carbon. Moreover, since the fuel pump 5 and the oil pump 8 are superposed and driven by one pump shaft 3,
The structure can be simplified. Since the fuel is sucked by the fuel pump 5, the position of the fuel tank 14 may be lowered.

Further, since the fuel pump 5 is disposed in the upwardly opened concave portion 6b formed in the upper wall 6a of the crankcase 6, the pump case is eliminated as compared with the fuel pump housed in its own pump case. Only the number of parts can be reduced and the structure for sealing oil can be simplified. Further, since the fuel passage (the fuel introduction passage 13 and the fuel discharge passage 18) communicating with the fuel pump 5 and the oil introduction port 13b communicating with the introduction side fuel passage 13 are integrally formed with the upper wall 6a of the crankcase 6, the lubricating oil It is possible to reduce the number of members for merging the fuel passage and the fuel passage, and since the piping configuration of each hose around the upper wall 6a of the crankcase 6 is simplified, the hoses do not intersect with each other, and ,
The hose connecting the oil pump 3 and the fuel pump 8 can be made short.

[Effect of device]

As described above, according to the present invention, it is possible to lubricate the engine parts evenly and uniformly with the well-mixed oil, so that the amount of lubricating oil mixed and the amount of lubricating oil consumed can be reduced to reduce the amount of white smoke in the exhaust gas. Generation and clogging of carbon can also be prevented.

Further, since the pump case is removed, the number of parts can be reduced and the structure for sealing the lubricating oil can be simplified.

Further, it is possible to reduce the number of members for merging the lubricating oil path and the fuel path, and the hoses do not intersect with each other around the upper wall 6a of the crankcase 6.

Furthermore, since the fuel pump 5 and the oil pump 8 are overlapped and driven by one pump shaft 3, the structure can be simplified.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a partially longitudinal side view of a main portion, and FIG. 2 is a side view. 1 ... Crank shaft, 2 ... Drive gear, 3 ... Pump shaft, 4 ... Driven gear, 5 ... Fuel pump, 6 ...
… Crankcase, 6a …… Crankcase top wall, 6b…
… Concave part, 8 …… Oil pump, 9 …… Drive shaft, 10
…… Oil pump inlet, 11 …… Oil tank, 12 ……
Hose, 13 …… Inlet side fuel passage, 13a …… Fuel inlet, 1
3b …… Oil inlet, 14 …… Fuel tank, 15 …… Hose, 16 …… Oil pump outlet, 17 …… Hose, 18 ……
Outlet side fuel passage, 18a ... Outlet port, 19 ... Hose, 20 ...
... carburetor, C ... drive shaft core.

Claims (1)

(57) [Scope of utility model registration request] 1. A crankshaft (1) extending in a substantially horizontal direction in a crankcase (6), and a driven gear (4) which meshes with a driving gear (2) of the crankshaft (1) at a right angle, and extends in a substantially vertical direction to a crankcase (6). The pump shaft 3 is rotatably supported, and is rotatably driven by the pump shaft 3 which is arranged in an upper open outer recess 6b formed in the upper wall 6a of the crankcase 6 at the outer periphery of the upper end of the pump shaft 3. Fuel pump 5
And an oil pump 8 mounted on the crankcase 6 coaxially with the drive shaft core C of the fuel pump 5 on the upper part of the fuel pump 5, and a drive shaft 9 provided at the lower end of the oil pump 8.
A fuel supply device for a two-cycle engine in which the fuel pump 5 and the oil pump 8 are simultaneously driven by one pump shaft 3 by being fitted into and engaged with the center of the upper end portion of the pump shaft 3, Inside the upper wall 6a of the case 6, a fuel introduction port 13a at one end is integrally projected on the upper wall 6a, and an introduction side fuel passage 13 communicating with the fuel pump 5 at the other end is integrally formed. Further, a hose 15 communicating with a fuel tank 14 is connected to the fuel introduction port 13a, and a hose 12 communicating with an oil tank 11 is connected to the inlet 10 of the oil pump 8, while the oil pump 8 Exit of
16 is connected via a hose 17 to an oil introduction port 13b integrally formed on the upper wall 6a of the crankcase 6, which communicates with the introduction side fuel passage 13 on the downstream side of the fuel introduction port 13a. Further, inside the upper wall 6a of the crankcase 6, a lead-out side fuel passage 18 for pumping the mixed oil of fuel and lubricating oil from the fuel pump 5 is provided, and a downstream end of the lead-out side fuel passage 18 is provided. A fuel supply device for a two-cycle engine, characterized in that a hose 19 having one end connected to the carburetor 20 is connected to the outlet 18a.