JPS6229722A - Fuel pump device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To make relatively large capacity generable, besides simple in structure, by interconnecting a suction pressure chamber of a fuel pump to a suction pressure source via a solenoid valve to be opened or closed according to an engine running state. CONSTITUTION:When a solenoid valve to be opened or closed by an engine running state is opened, suction pressure to be taken out of a suction pressure port at the upstream of a throttle valve is led into a suction pressure chamber 45 of a fuel pump. Two diaphragms 43 and 44 are displaced in a sense to come nearer to each other against spring force of a compression coiled spring 48. With this constitution, volume in an empty chamber 57 increases, a valve plate 65 is opened, and fuel out of a fuel tank is led into this empty chamber 57. When the solenoid valve is closed, the atmosphere is led into the suction pressure chamber 45 via an air filter 50 and a jet 51, and these diaphragms 43 and 44 are separated from each other. The volume of the empty chamber 57 decreases, a valve 66 opens, and fuel in the empty chamber 57 is led into a fuel storage part of a carburetor. A supply of fuel is propotioned to on-off frequency of the solenoid valve.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a fuel pump device installed between a fuel tank of an internal combustion engine and a fuel supply device consisting of a carburetor or the like.
In particular, the present invention relates to a fuel pump device for an internal combustion engine of the type described above which is operated by negative pressure.

<Conventional Technology> Conventionally, mechanically driven pumps connected to the output shaft of the internal combustion engine, motorized pumps driven by electric power, solenoid pumps, etc. have been widely used as fuel pumps to supply fuel to internal combustion engines. .

In addition, a fuel pump that utilizes changes in the internal pressure of the crank chamber and pulsations in the intake negative pressure has been proposed, and Japanese Patent Laid-Open No. 58-1
Publication No. 5oo6a@ proposes a fuel pump that utilizes the oil pressure of lubricating oil.

<Problems to be solved by the invention> However, mechanically driven fuel pumps are susceptible to layout constraints because they directly utilize engine output, and are installed adjacent to the engine body, so The problem is heat transfer from the

Electrically driven fuel pumps are generally expensive due to their complex construction. Furthermore, in the case of a diaphragm pump that utilizes the pulsations of the crankcase internal pressure and suction negative pressure, the discharge pressure and discharge area tend to be insufficient.

In view of these drawbacks of the prior art, the main object of the present invention is to provide a fuel pump for an internal combustion engine that has a simple structure and can generate a relatively large capacity.

Means for Solving the Problems According to the present invention, the inside of the casing is partitioned into a pump chamber and a negative pressure chamber by a diaphragm biased by a spring toward the pump chamber. and the pump chamber is divided by two check valves into a suction chamber that directly communicates with the suction port, a discharge chamber that directly communicates with the discharge port, and a variable volume chamber that is located between the two chambers and is in contact with the diaphragm. The internal combustion engine is characterized in that the negative pressure chamber communicates with a negative pressure source via an electromagnetic on-off valve that is controlled to open and close depending on the operating state of the engine, and also communicates with the atmosphere via a leak jet. This is accomplished by providing an engine fuel pump device.

<Operation> In this way, if the negative pressure introduced into the negative pressure chamber is intermittent by the electromagnetic on-off valve and the negative pressure is gradually released by the leak jet, changes in the negative pressure in the negative pressure chamber can be prevented. The diaphragm reciprocates accordingly, providing a pumping effect. Moreover, by appropriately setting the amount of negative pressure related to the electromagnetic on-off valve and the intermittent frequency of negative pressure depending on the operating state of the engine, desired pump characteristics can be obtained extremely easily.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic vertical sectional view of a carburetor to which a fuel pump device according to the present invention is applied, and is composed of an air horn portion 3 having an air bone 2 and a carburetor body 1 having an intake passage 4, and is a so-called down-type carburetor. It is a draft type vaporizer. A venturi 5 is formed inside the intake passage 4, and
A throttle valve 7 is pivotally supported by a valve shaft 6 on the downstream side thereof.

On the side of the intake passage 4, a fuel storage chamber 8 is formed between the two casings, and a cylindrical portion 9 having an upper opening is erected on the bottom surface of the fuel storage chamber 8.

A fuel supply pipe 11 is connected to a side surface of the cylindrical portion 9, and the other end of the supply pipe is connected to a discharge pipe 11a of a pump 10. Further, a fuel storage portion 9a is formed inside the cylindrical portion 9, and an annular chamber 9b is formed around the fuel storage portion 9a. The bottom of the annular chamber 9b is connected to the pump 10 via a fuel return outlet 12 and a fuel return line 12a. Furthermore,
A fuel passage 1 is provided on the bottom surface of the fuel storage portion 9a inside the cylindrical portion 9.
4 is connected to one end, and the other end of the nuclear fuel passage is connected to the empty chamber 15.

The open end of the fuel passage 14 that opens toward the cavity 15 forms a valve seat that cooperates with a valve body 17, and the valve body 17 is driven by a solenoid 18 to open and close the open end of the fuel passage 14. I can do it. The cavity 15 communicates with the interior of the air horn 2 via a bleed air passage 16, and also with a main nozzle 19 fitted with, for example, porous ceramic.

Intake path 4 near the upstream side of throttle valve 7 in the fully open position
The slow nozzle 21 opens toward
1 communicates with a slow fuel passage 20 via a cavity 22, and the slow fuel passage 20 communicates with the bottom of the fuel storage portion 9a via a passage (not shown). Slow fuel passage 20
The open end facing the empty chamber 22 forms a valve seat that cooperates with a valve body 23, and the valve body 23 is driven by a solenoid 24.

Two negative pressure ports for taking out negative pressure are bored in the intake passage 4 slightly upstream of the throttle valve 7, and are connected to the intake passage 4 via a conduit 30, a surge tank 31, a solenoid valve 32, and a conduit 33, which will be described later. It is connected to the fuel pump 10. solenoid 18,
The solenoid 24 and the solenoid valve 32 are connected to the signal line 26.
Opening and closing are controlled by the control unit 25 via 27 and 28.

FIG. 2 shows in detail a first embodiment of the fuel pump device according to the present invention, in which an intermediate casing 40 made of an annular member and sub-casings 41 connected to both ends of the intermediate casing 40 via diaphragms 43 and 44, respectively. It consists of .42.

A negative pressure chamber 45 defined by the intermediate casing 40 and both diaphragms 43 and 44 is connected to the negative pressure passage 33 via a negative pressure inlet 49 and is connected to the atmosphere via a leak jet 51 and an air filter 50. It's communicating. Also, both diaphragms 43 and 44 have retainers 46 and 47, respectively.
are biased in directions away from each other by a compression coil spring 48 via. The other side of the retainer 46.47 has a support portion 4 integrally formed with the sub-casing 41.42.
1a and 42a.

Inside the sub casing 41 is a liner 54 having a substantially bottomed cylindrical shape.
The liner 54 and the diaphragm 43 form an annular cavity 57 as a variable volume chamber surrounding the support portion 41a. The sub-casing 41 is provided with bulging portions 41a and 41b that bulge out into a substantially bottomed cylindrical shape, and these bulging portions 41a and 41b and the liner 54 form cavities 56 and 58. In this way, a pump chamber consisting of empty chambers 57, 56, and 58 is formed within the subcasing 41. The empty space 56 as a suction chamber is the suction port 52
The empty chamber 58 serving as a discharge chamber communicates with the discharge port 53.

The liner 54 is provided with communication holes 59.60 corresponding to the empty chambers 56.58, and these communication holes 59.60 are as follows.
They are closed by valve plates 65,66 which are biased by helical compression springs 63,671 against retainers 61,62 each secured to liner 54. However, the valve plates 65, 66 of both sections are provided on different sides of the liner 54, respectively.

The inside of the sub-casing 42 also has the same configuration as the inside of the sub-casing 41, and is arranged symmetrically with respect to each other, and corresponding parts are given the same reference numerals. Note that the empty chambers 56 and 58 of the sub-casing 42 communicate with an inlet port 67 and a discharge port 68, respectively.

Next, the operation of the fuel pump 10 shown in FIG. 2 will be explained.

In FIG. 1, the intake negative pressure introduced from the negative pressure boat 29 reaches the solenoid valve 32 via the pipe line 30 and the surge tank 31, and the solenoid valve 32 is controlled in duty ratio by the control unit 25, and is operated intermittently. Negative pressure is introduced into the negative pressure chamber 45 of the fuel pump 10 via the conduit 33.

When the solenoid valve 32 is in the open state, both diaphragms 43.4
4 are displaced toward each other against the spring force of the compression coil spring 48. In the pump chamber on the sub-casing 41 side, the volume of the empty chamber 57 increases, so the valve plate 66 is held in the closed state, but the valve plate 65 resists the spring force of the spring 63 and does not open. The fuel introduced into the cavity 56 from the fuel tank 13 via the pipe line 34 passes through the communication hole 59 and is introduced into the cavity 57.

Next, when the solenoid valve 32 closes, the atmosphere enters the air filter 5.
The diaphragm 43.
44 are driven away from each other by the spring force of the compression coil spring 48.

As a result, the volume of the empty chamber 57 decreases, and the valve plate 65 becomes closed, but the valve plate 66 opens against the spring force of the compression coil spring 64, and the fuel in the empty chamber 57 flows into the communication hole 60. and vacant room 5
8 and is discharged from the discharge port 53, and introduced into the fuel storage section 9a of the carburetor via the pipe line 11a.

In this way, as the solenoid valve 32 opens and closes, the fuel tank 1
3 of the fuel is supplied to the carburetor, and its supply has a proportional relationship with the frequency of opening and closing of the solenoid valve 32. In particular, since the intake port 29 is provided on the upstream side of the throttle valve 7, a relatively small amount of negative pressure is introduced into the fuel pump 10 when the throttle is closed, which does not consume much fuel, resulting in an excessive supply of fuel. Waste can be avoided.

Incidentally, since the discharge amount of the fuel pump 10 is set to at least slightly exceed the actual fuel consumption amount, the fuel supplied to the fuel storage portion 9a is constantly distributed from the upper end of the cylindrical portion 9 to the outer peripheral portion. overflow towards the target. The overflowing fuel is transferred to the sub-casing 4 via the return outlet 12 at the bottom of the annular chamber 9b on the outer periphery of the cylindrical portion 9 and the return fuel pipe 12a.
The fuel reaches the suction port 67 associated with the pump chamber on the second side and is returned to the fuel tank 13 via the discharge port 68 and the return line 35 by the action of the fuel pump 100. In this way, the fuel is circulated by the pump 10 from the fuel tank 13 to the carburetor, and from the carburetor to the fuel tank 13.
The same head of fuel is always stored in the fuel storage section 9a of the carburetor.

The fuel stored in the fuel storage part 9a inside the cylindrical part 9 is
The main nozzle 1 is connected through the fuel passage 14 from the bottom of the same part.
9 will be supplied.

The control unit 25 has intake negative pressure P8, throttle opening θ, engine speed N, cooling water temperature t1, and atmospheric temperature t.
, acceleration 91 atmospheric pressure Pa, oxygen concentration in exhaust gas C1
A signal indicating the operating state of the engine, such as the state 19 of the ignition switch, is input, and the solenoid 18.24 is driven by a predetermined map control, thereby controlling the amount of fuel discharged from the main nozzle 19 and the slow nozzle 21. Amount controlled. Similarly, the solenoid valve 32 associated with the pump 10 is also controlled to open and close by the control unit 25.

FIG. 3 shows a second embodiment of the fuel pump device according to the present invention, and parts corresponding to those in the previous embodiment are given the same reference numerals and detailed explanations will be omitted. This embodiment differs from the embodiment described above only in that the sub-casing 41 is provided only on one side of the intermediate casing 40, and the internal structure of the sub-casing itself is the same as that of the embodiment described above. In the embodiment, two such pump devices are used.

Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above, and can be implemented with various modifications and changes. For example, the means for opening and closing the negative pressure pipeline is not limited to the above-mentioned solenoid valve 32, but may be a rotary valve driven by a motor. Further, the fuel pump device of the present invention can be widely applied not only to the carburetor of the above embodiment but also to other types of carburetors.

<Effects of the Invention> As described above, according to the present invention, it is possible to generate a capacity equivalent to that of an electric pump with a configuration as simple as that of a conventional negative pressure responsive diaphragm pump, and it is possible to reduce costs. It has a big effect.

In addition, there are fewer restrictions on the layout, and the pump characteristics can be controlled extremely easily using signals from the control device, making it possible to achieve the appropriate amount of fuel supply corresponding to the operating conditions of the engine. is extremely large.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical sectional view showing the entire carburetor to which a fuel pump device according to the present invention is applied. FIG. 2 is a longitudinal sectional view showing in detail a first embodiment of the fuel pump device according to the present invention. FIG. 3 is a longitudinal sectional view showing in detail a second embodiment of the fuel pump device according to the present invention. 1... Carburetor body 2... Air horn 3...
Air horn part 4...Intake path 5...Venturi
6... Valve shaft 7... Throttle valve 8... Fuel storage part 9... Cylindrical part 9a... Fuel storage part 9b... Annular chamber 10... Fuel pump 11
...Fuel population 11a...Discharge pipe 12...
Fuel return outlet 12a...Return pipe line 13...Fuel tank 14...Fuel passage 15...Empty room
16... Air bleed passage 17... Valve body
18... Solenoid 19... Main nozzle 20.
...Slow fuel passage 21...Slow nozzle 22...
・Vacancy 23...Valve body 24...Solenoid 25...Control unit 26-28...Signal line 29
...Negative pressure port 30...Pipe line 31...Surge tank 32...Solenoid valve 33-35...Pipe line 4
0... Intermediate casing 41.42... Sub casing 41a, 42a... Support portion 43.44... Diaphragm 45... Negative pressure chamber 46.47... Retainer 4
8... Compression coil spring 49... Negative pressure inlet 50...
・Air filter 51...Leak jet 52...
Suction port 53...Discharge port 54...Liner
56.57.58... Vacancy 59.60... Communication hole 61.62... Retainer 63.64... Compression coil spring 65.66... Valve plate 68... Inlet port 66.・・・
Discharge port patent applicant: Honda Motor Co., Ltd. Representative: Patent attorney: Yo Oshima - Figure 2

Claims (2)

[Claims] (1) The inside of the casing is divided into a pump chamber and a negative pressure chamber by a diaphragm biased by a spring toward the pump chamber, and the pump chamber has a suction chamber that directly communicates with the suction port, and a discharge port. A discharge chamber that communicates directly with the diaphragm, and a variable volume chamber located between the two chambers and in contact with the diaphragm are divided by two check valves, and the negative pressure chamber is an electromagnetic valve that is controlled to open and close depending on the operating state of the engine. A fuel pump device for an internal combustion engine, characterized in that it communicates with a negative pressure source via an on-off valve and communicates with the atmosphere via a leak jet. (2) The fuel pump device for an internal combustion engine according to claim 1, wherein two pump chambers are arranged substantially symmetrically on both sides of the negative pressure chamber.