JPH09209863A - Fuel supply device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriate an existing diaphragm pump capable of transmitting a large pulsating pressure change generated in an air intake route to a diaphragm pump by relaxing it and designed in consideration of a small pulastile change generated in a crankcase as it is without remodulling it. SOLUTION: A derived end part 3 of a pulsating pressure introduction passage 2 is connected to an air intake route 5 to a combustion chamber and a contracted part 6 is formed in the pulsating pressure introduction passage 2 in a fuel supply device of an engine devised to drive a diaphragm pump 1 in accordance with pulsating pressure generated on a pulsating pressure generating point 4 by using the diaphragm pump 1 as a fuel supply pump, deriving the pulsating pressure introduction passage 2 from this diaphragm pump 1 and connecting the derived end part 3 of this pulsating pressure introduction passage 2 to the pulsating pressure generating point 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply system for an engine, and more particularly to a system capable of suppressing malfunction of a diaphragm pump.

[0002]

2. Description of the Related Art As a prior art of a fuel supply device for an engine, a diaphragm pump is used as a fuel supply pump, a pulsating pressure introducing passage is led out from the diaphragm pump, and a leading end of the pulsating pressure introducing passage is drawn out from the diaphragm pump. There is a system in which the diaphragm pump is driven based on the pulsating pressure generated at this pulsating pressure generating point. In this conventional technique, the outlet end of the pulsating pressure introducing passage is connected to the inside of the crankcase, and the diaphragm pump is driven based on the pulsation generated in the crankcase due to the lifting and lowering of the piston.

[0003]

In the above-mentioned prior art, the oil droplets of engine oil scattered in the crankcase may enter the pulsating pressure introducing passage and block the passage, thereby impairing the operation of the diaphragm pump. .

An object of the present invention is to provide a fuel supply system for an engine capable of suppressing malfunction of the diaphragm pump.

[0005]

According to the present invention, as shown in FIG. 1, a diaphragm pump 1 is used as a fuel supply pump, a pulsating pressure introducing passage 2 is led out from the diaphragm pump 1, and the pulsating pressure introducing passage 2 is introduced. In the fuel supply device for the engine, the outlet end 3 of is connected to the pulsating pressure generating point 4 and the diaphragm pump 1 is driven based on the pulsating pressure generated at the pulsating pressure generating point 4. It is characterized by having done.

That is, the discharge end portion 3 of the pulsating pressure introducing passage 2 is connected to the intake passage 5 to the combustion chamber, and the throttle portion 6 is formed in the pulsating pressure introducing passage 2.

[0007]

According to the present invention, the following operational effects are obtained. Since the derivation end 3 of the pulsation pressure introduction passage 2 is connected to the intake passage 5, only atomized fuel in the spark ignition type engine and air in the diesel engine enter the pulsation pressure introduction passage 2, respectively, and the engine oil There is no possibility that such high-viscosity oil droplets will enter, and it is possible to suppress malfunction of the diaphragm pump 1 due to blockage of the pulsation pressure introduction passage 2.

Since the throttle portion 6 is formed in the pulsating pressure introducing passage 2, a large pulsating pressure change generated in the intake passage 5 can be alleviated and transmitted to the diaphragm pump 1, and a small pulsating change generated in the crankcase can be transmitted. The existing diaphragm pump designed on the assumption can be used as it is without modification.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. 1 and 2 are diagrams for explaining the first embodiment. As shown in FIG. 2, in the first embodiment, a vertical air-cooled gasoline engine is used. The structure of this engine is as follows. That is, the fan case 8 is assembled on the front side of the engine body 7, the fuel tank 9 is arranged on the side of the engine body 7, and the cylinder head 10 and the head cover 11 are assembled on the upper part of the engine body 7 from the front side of the cylinder head 10. The intake pipe 12 is led out sideways, and the carburetor 13 and the air cleaner 1 are attached to the lead-out end of the intake pipe 12.
4 and are attached.

In this embodiment, as shown in FIG. 1, a diaphragm pump 1 is used as a fuel supply pump, and a pulsation pressure introducing passage 2 is led out from the diaphragm pump 1.
The leading end 3 of the pulsating pressure introducing passage 2 is connected to the pulsating pressure generating point 4
The diaphragm pump 1 is driven based on the pulsating pressure generated at the pulsating pressure generating point 4. Then, in order to suppress malfunction of the diaphragm pump 1, the discharge end portion 3 of the pulsation pressure introduction passage 2 is connected to the intake passage 5 to the combustion chamber, and the throttle portion 6 is provided in the pulsation pressure introduction passage 2.
Is formed.

The diaphragm pump 1 is fixed to the carburetor 13. The inside of the diaphragm pump 1 is the diaphragm 1
5 is divided into a fuel pressure feed chamber 16 and a pulsation pressure introduction chamber 17, the combustion pressure feed chamber 16 is communicated with the float chamber 18 of the carburetor 13 and the fuel tank 9, and the pulsation pressure introduction chamber 17 is passed through the pulsation pressure introduction passage 2. To communicate with the intake passage 5 and operate the diaphragm 15 by the intake pulsation pressure, whereby the fuel tank 9
From the fuel pumping chamber 16 to the float chamber 18 of the vaporizer 13
It is designed to supply fuel to.

In this embodiment, the outlet end 3 of the pulsating pressure outlet passage 2 is provided with a throttle portion 6 to suppress the atomized fuel from entering the pulsating pressure inlet passage 2 through the intake passage 5. The derivation end portion 3 of the pulsation pressure derivation passage 2 is connected downward toward the intake passage 5, and even if the fuel is condensed at the derivation end portion 3 of the pulsation pressure introduction passage 2, it is naturally dropped into the intake passage 5. Is done. The lead-out end 3 of the pulsating pressure lead-out passage 2 is composed of a metal pipe 19, and the end of the lead-out end 3 is press-fitted into a connection hole 20 formed in the intake pipe 12 so as to be fixed therein. The orifice 21 is fitted. This cylindrical orifice 21
Uses the fuel jet 22 of the carburetor 13 and is fixed to the end of the metal tube 19 by screw fitting.

In the second embodiment shown in FIG. 3, the lead-out end 3 of the pulsating pressure lead-out passage 2 is composed of a metal rod 24 having a drilled hole 23, and the small-diameter portion 25 of the drilled hole 23 is used as the throttle portion 6. is there. Other configurations are the same as those in the first embodiment, and the configuration shown in FIG.
Among them, the same elements as those of the first embodiment are denoted by the same reference numerals. Further, in the third embodiment shown in FIG. 4, the throttle valve 26 is used in the throttle portion 6 so that the throttle resistance can be adjusted. Other configurations are the same as those in the first embodiment, and in FIG.
The same elements as those in the first embodiment are designated by the same reference numerals.

The contents of the respective embodiments of the present invention are as described above, but the present invention is not limited to the above embodiments. For example, in the above embodiment, a gasoline engine has been described, but the present invention can also be applied to other spark ignition type engines such as gas engines and kerosene engines, and diesel engines.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a main part of a first embodiment.

FIG. 2 is an overall front view of the first embodiment.

FIG. 3 is a vertical cross-sectional view of a main part of the second embodiment.

FIG. 4 is a vertical cross-sectional view of a main part of a third embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Diaphragm pump, 2 ... Pulsation pressure introduction passage, 3 ... Derivation end part, 4 ... Pulsation pressure generation part, 5 ... Intake path, 6 ... Throttling part.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location // F04B 43/02 F04B 43/06 A

Claims (1)

[Claims] 1. A diaphragm pump (1) is used as a fuel supply pump, and a pulsating pressure introducing passage (2) is led out from the diaphragm pump (1), and a leading end portion (3) of the pulsating pressure introducing passage (2). Is connected to the pulsating pressure generating point (4), and the diaphragm pump (1) is driven based on the pulsating pressure generated at the pulsating pressure generating point (4). The outlet end (3) of the introduction passage (2) is connected to the intake passage (5) to the combustion chamber, and the throttle portion is provided in the pulsation pressure introduction passage (2).
An engine fuel supply device characterized in that (6) is formed.