US3556488A

US3556488A - Carburetor with fluid elements

Info

Publication number: US3556488A
Application number: US840671A
Authority: US
Inventors: Toshinori Arikawa; Shigetaka Takada
Original assignee: Aisan Industry Co Ltd
Current assignee: Aisan Industry Co Ltd; Carter Automotive Co Inc
Priority date: 1968-07-10
Filing date: 1969-07-10
Publication date: 1971-01-19
Anticipated expiration: 1988-01-19

Abstract

A carburetor employing three pure fluid amplifiers for controlling the flow of fuel to a cylinder. Fuel from a source is supplied to the power input of a first amplifier. The power outputs of this amplifier are connected to the power inputs of the other two amplifiers. The fuel supplied to the two amplifiers may be controlled by the amplifiers to flow to the cylinder and/or to return to the fuel source. Pressure within the cylinder is sensed to control the fluid amplifiers whereby fuel is supplied to the cylinder from one of the two amplifiers during idling or partial power output and fuel is supplied to the cylinder from both of the two amplifiers during full power output.

Description

United States Patent Appl. No. Filed Patented Assignee Priority CARBURETOR WITH FLUID ELEMENTS 9 Claims, 8 Drawing Figs.

US. Cl 261/36, 123/119.261/69,261/41,137/8l.5

Int. Cl F02m 7/06 Field ofSearch..... 261/361, 69,69.l,4l; 137/8l.5; 123/119 References Cited UNITED STATES PATENTS 6/1965 Bauer Primary Examiner-Tim R. Miles Attorney-Griffin, Branigan & Kindness ABSTRACT: A carburetor employing three pure fluid amplifiers for controlling the flow of fuel to a cylinder. Fuel from a source is supplied to the power input of a first amplifier. The power outputs of this amplifier are connected to the power inputs of the other two amplifiers. The fuel supplied to the two amplifiers may be controlled by the amplifiers to flow to the cylinder and/or to return to the fuel source. Pressure within the cylinder is sensed to control the fluid amplifiers whereby fuel is supplied to the cylinder from one of the two amplifiers during idling or partial power output and fuel is supplied to the cylinder from both of the two amplifiers during full power output.

PATENTEUJAN 1 919?:

Fig.2

Fig. I

CARBURETOR WITII FLUID ELEMENTS PRIOR ART FIG. 1 shows a typical carburetor of the prior art employing a fluid amplifying element. It is made up of a fluid amplifying element 1, a fuel pump 2, a fuel tank 3, a cylinder 4 and a throttle valve 5. In this carburetor, the (fluid) circuit, which is connected to both terminals of the control circuit C l and C of the fluid amplifying element 1, is so arranged that it opens to both upstream and

downstream ports

6 and 7 of the throttle valve in the cylinder 4. The three power output terminals P P P of the fluid amplifying element 1 are respectively connected to the (fluid) circuits which open into the fuel tank 3, the ports 8 and 9 of the cylinder 4. This type of carburetor uses only one fluid element, and the fuel flowing out of the power output outlets of the fluid element is the only fuel which is used during both the idling and the full operation of the engine. Therefore, this carburetor cannot fully satisfy the fuel requirement of the engine, which varies very widely, i.e., the quantity of fuel required during idling is very small but during full operation is very large. In order to overcome this deficiency, various auxiliary equipment has to be added to the carburetor. Furthermore, mass production of this type of carburetor is difficult.

SUMMARY OF THE INVENTION An object of the present invention is to provide a carburetor employing plural fluid amplifying elements, said carburetor having none of the disadvantages of the prior art.

An object of the present invention is to provide a carburetor having a primary fluid amplifier and a secondary fluid amplifier, the amplifiers being interconnected whereby fuel from a supply source is applied through the primary and then the secondary amplifier to a cylinder, and means for controlling the amplifiers in response to the pressure in the cylinder.

An object of the present invention is to provide a carburetor employing first and second secondary fluid amplifiers, a primary fluid amplifier for proportioning the flow of fuel from a source to each of the secondary amplifiers, a cylinder, means for sensing the pressure in said cylinder for controlling all of the fluid amplifiers whereby the first secondary amplifier feeds fuel to the cylinder during periods of idling and partial power output and both the secondary amplifiers feed fuel to the cylinder during periods of full power output.

An object of the invention is to provide a carburetor as described above and including a further control means for the second secondary amplifier. In one embodiment, the control means comprises a fluid valve actuated by a mechanism that moves a throttle valve in the cylinder. In another embodiment, the control means comprises a mechanical valve operated by the pressure in the cylinder downstream of the throttle valve.

BRIEF EXPLANATION OF THE FIGURES FIG. 1 shows the pipe arrangement of a well-known carburetor with fluid elements;

FIG. 2 is a fluid element;

FIG. 3 shows the pipe arrangement of the carburetor;

FIG. 4 is a longitudinal section of the pressure regulator used in the carburetor shown in FIG. 3;.

FIG. 5A and B show the structures of other types of pressure regulators;

FIG. 6 is a longitudinal section of a pressure regulator having a structure different from that of the regulators mentioned above; and

FIG. 7 is a diagram showing the characteristic capacities of the carburetor described in FIG. 3.

This invention will be explained by the use of FIG. 2 to FIG.

outlets divided by the splitter 10. C and C are the terminals of the control circuit connected to the control nozzle. When high energy fluid is supplied to the supply port Pro at the fluid element 10, shown in FIG. 2, and if there is no input signal at the control circuit terminals C and C most of the high energy fluid supplied will rush directly to the power output outlet I because the main jet connected to the supply port P and the inlet connected to the power output outlet P are located on the straight line connecting Pm and Pig as judged from the shape of the splitter 10' shown in thc.FlG. Only a small quantity of the remaining fluid which has not been split completely is pushed through the power output outlet P As for the input signal, when (low energy) fluid flows from one terminal of the control circuit C to the other terminal C the main jet flow is deviated and the output is gradually transferred from one power output outlet P 0 the other power output outlet P depending on the size of the input signal given. In this way, the fluid element exerts its amplifying action by controlling the high energy fluid by the use of the low energy fluid. In FIG. 3, three

elements

10, and 30 are used as the fluid element.

In FIG. 3, the symbols used are the same as those used in I FIG. 2. For the symbol of the control circuit terminals, C is pump starts to operate first, the fuel flowing out of the fuel 6. FIG. 2 is an enlarged FIG. of the first fluid element 10 used with the number of tlie fluid element and the number of the control circuit terminal as its subscripts. For the power output outlet, the symbol P is used with the fluid element number and the number representing the power output terminal as its subscripts. The element 30 is the same as the element 10, but the element 20 is different in that it contains three power output outlets. As shown in FIG. 3, the control circuit terminals of each element, C C and C are connected to the pipe which opens to the port 6 located at the upstream of the throttle valve in the cylinder 4. The control circuit terminals C and C of the

elements

10 and 20 are opened to the atmosphere, and the control circuit terminal C of the element 30 is connected to the pressure regulator 15 through the pipe 17. The pressure regulator in turn is connected to the one terminal of the pipe 16, the other terminal of which opens to the port 7 located at the downstream of the throttle 5. Therefore, the control circuit terminal 32 will receive the manifold vacuum of the port 7 at the downstream of the throttle 5 through the pressure regulator 15. One of the three power output outlets P of the element 20 is connected to the fuel tank 3 through the return circuit 13; the output opening P is connected to the pipe which opens to the idle port 11 located at the downstream of the throttle, and the other output outlet P is connected to the pipe which opens to the port 8. 12 is the idle adjusting screw which regulates the quantity of fuel supplied from the power output outlet P to the idle port 11 during engine idling. The structure of this ad justing screw is the same as that of the adjusting screw used to control the amount of fuel supplied to the idle port of the conventional carburetor without the fluid element.

The operation of the carburetor shown in FIG. 3 will be explained next. When the engine is not in operation and the fuel pump 2 will return to the fuel tank 3 from the power output outlet P of the fluid element 10 through the power output. outlet P of the fluid element 30. The remaining fuel, which has not been separated completely in the direction of the power output outlet P of the fluid element 10, will return to the fuel tank 3 from the power output outlet I through the power output outlet P of the fluid element 20 and the retum circuit 13. Therefore, no fuel is supplied to the cylinder 4 at this moment. When the engine starts to operate, a slight negative pressure will form at the port 6 connected to the control circuit terminal during the idling, and thus the negative pres sure will appear as an input signal on the control circuit terminals ll, 21, and 31 of the respective fluid elements I0, 20 and 30. However, the negative pressure from the port 7 at the downstream of the throttle will appear on the other control circuit terminal C of the fluid element 30, and thus the fluid element 30 will not operate. In this case, the

fluid elements

10 and 20 will operate first. In other words, the output of the fluid element 10, which has appeared almost completely at the power output outlet P will now be slightly shifted to the other power output outlet P, and thus the quantity of fuel supplied to the fluid element 20 is increased. In the fluid element 20, the fuel which has appeared almost completely at the power output outlet P due to the input signal. i.e., the negative pressure on the control circuit terminal C will also be transferred to some extent to the power output outlet P Furthermore, the suction vacuum of the engine will cause the formation of strong vacuum at the power output outlet P Consequently, the fuel is more easily transferred to the output outlet P and is supplied to the idle port 11.

When the throttle 5 is opened and the engine is in the state of partial power output, the vacuum input signal of the control circuit terminals C and C will become bigger due to the vacuum at the port 6. Subsequently, more fuel from the power output outlet P will be supplied to the fluid element 20, and the output fuel of the fluid element will be transferred further from the power output outlet P to the other power output outlet P Therefore, sufficient quantities of fuel can be supplied to the port 8.

The formation of the controlling vacuum depends on the amount of air sucked in by the engine, and the fuel flow may shift from the power output outlet P to P or'undergo successive shift from P to P to P depending on the pressures. In this way, the appropriate quantity of fuel for partial power output can be supplied to the port 8 of the cylinder from the power output outlet P through the partial power output nozzle 18.

As in the case of idling, the vacuum at the one control circuit terminal C of the fluid element 30 is larger than that at the other terminal C during the partial power output of the engine. The output fuel of the fluid element 30 therefore is always shifted to the direction of the power output outlet P .and is returned to the fuel tank 3 via the return circuit 14.

Even though the quantity of air sucked in by the engine is increased and the negative pressure at the port 7 becomes extremely large, the controlling vacuum at the control circuit terminal C will not exceed the preset value because of the action of the pressure regulator 15. Therefore, during the full power output of the engine, the controlling vacuum at the control circuit terminal C caused by the port 6 is larger than that at C and the output fuel of the fluid element 30 is shifted from the power output outlet P to P3,. Consequently, the fuel will also be supplied to the engine from the full power output nozzle 9 which opens at the port 19.

The structure of the pressure regulator is shown in FIG. 4.

The main body 21 contains the

openings

16 and 17"connected respectively to the

pipes

16 and 17 mentioned above, and also the ventilation hole 22 connected to atmospheric air. It is also equipped with regulating

screws

23 and 24 which adjust the throttle resistance of the opening 17 and the ventilation hole 22. When this pressure regulator is installed on the carburetor shown in FIG. 3, the vacuum at the port 7 located at the downstream of the throttle valve is lowered by at as mentioned before during the full power output with the' manifold vacuum greater than 60 mm. Hg. Consequently, the fuel can also be supplied from the full power output nozzle 19 depending on the quantity of air sucked in by the engine (namely, suction vacuum).

FIG. 5 shows another type of pressure regulator. This regulator does not regulate the pressure directly. Rather, it acts like a switch valve and exerts the same regulating effect as that of the pressure regulator shown in FIG. 4. As shown in FIG. 5,

the main body contains the opening 17 connected to the pipe 17 shown in FIG. 3 and the ventilationhole 22 connected to atmospheric air. The piston 26 connected to the cam interlocked with the throttle valve 5 is located within the main body 21 and can be moved freely. The spring 27 always presses the piston 26 against the cam 25. The piston 26 has a through hole 26 which can be connected to either the opening 17 or the ventilation hole 22 asshown in FIG. 5(B), depending on the position of the piston 26. One can adjust the relative position of the cam 25 and the throttle valve 5 in such a way that when the opening of the throttle valve exceeds the preset degree of opening, the cam 25 vvilI cause the opening 17 to be connected to the ventilationhole 22 as shown in FIG. 5(B). When the opening of the throttle valve is below the preset degree of opening, the piston 26 will shut off the connection between the opening 17' and the ventilation hole 22 as shown in FIG. 5(A). In this way, the fluid element 30 will start to operate only during the period of the full power output in which the opening of the throttle valve exceeds the preset degree of opening as mentioned above, and the fuel is also supplied through the full power output nozzle.

FIG. 6 shows the structure of another device whose function is the same as that of the pressure regulator 15. The piston 28 is always pushed to the right by the spring 29. The manifold vacuum at the opening 16, connected to the pipe which opens at the port 7 located at the downstream of the throttle valve, will suck the piston 28 to the left to shut off the opening 17' which was originally connected to atmospheric air via the through hole 28. If the force of the spring 29 is so adjusted by the use of the regulating screw 31 that the piston 28 will be sucked to the left to shut off the opening 17' when the manifold vacuum is about 60 mm. Hg, the piston 28 will be pushed to the right by the reaction of the spring 29 during the period of full power output, and the opening 17 .is connected to atmospheric air. Subsequently, the fluid element 30 will start to operate and the fuel is also supplied from the full power output nozzle.

The pressure regulators (or pressure regulators which act like a switch valve) shown in FIGS. 4 to 6 can regulate the input signal applied on the control circuit terminals of the fluid element 30 in accordance with the quantity of air sucked in and the degree of opening of the throttle valve. It is also possible to operate the pressure regulators electrically by the use of widely-known devices.

Instead of adjusting the input signal (controlling vacuum) placed on the control circuit terminal by the action of the fluid element during the period of full power output, the expected result could also be obtained by the procedures mentioned below. One control circuit terminal C of the fluid element 30 is connected to atmospheric air, and a switch valve is installed on the passage between the power output outlet P and the full power output nozzle 19. The degree of opening of the throttle valve or the manifold vacuum is then so adjusted that the switch valve will open only during the period of full power output.

The controlling vacuum of all elements is obtained from the vacuum outlet which opens to the common port 6. It is also possible to have different vacuum outlets for each element with different controlling vacuums.

Adjustable throttling devices such as idle adjusting screws or jets can be installed on part or on the entire portion of the passage between the power output outlet P of each element and the control circuit terminals C to achieve the microadjustment of the quantity of fuel supplied to the engine.

The fuel characteristics of the carburetor shown in FIG. 3 are given in FIG. 7. During the period of idling and partial power output in which the vacuum at the cylinder is relatively small, the fuel is supplied almost entirely from the power output outlets P and P of the element 20. During the period of full power output, the power output outlet 31 of the element 30 can also supply the fuel additively to the engine, and thus the engine is sufficiently supplied with the fuel.

In the carburetor shown in the FlGS., the first fluid element used has the structural capacity of supplying almost all the output fuel from one power output outlet P in the absence of the input signal. However, fluid elements with a main jet or splitter, by which the output fuel can be supplied almost equally from the two output openings P and P in the absence of the input signal, can also be used.

The carburetor invented can supply a very small quantity of fuel during idling and a very large quantity of fuel during the period of full power output. The fluid amplifying elements used in the carburetor can automatically control the quantity of fuel flow within a very wide range as required by the engine. The cost of manufacture of the carburetor is low and its mass production is feasible. The fluid element used has a long life.

We claim: 1. A carburetor for an internal combustion engine, said carburetor comprising:

a primary fluid amplifier through which all fuel must flow to reach said engine;

said primary fluid amplifier having a power input for receiving said fuel, first and second power outlets, and a control input for selectively proportioning the fuel received at said power input between said power outlets;

first and second secondary fluid amplifiers, said secondary amplifiers each having a power input, first and second power outlets, and a control input for selectively proportioning fuel received at said power input between said power outlets;

first means connecting the first and second power outlets of said primary amplifier to the power inputs of said first and second secondary amplifiers, respectively;

a cylinder;

second means connecting the second power outlet of each secondary amplifier to said cylinder; and

third means for sensing the pressure in said cylinder and conveying an indication of said pressure to the control inputs of said primary amplifier and said secondary amplifiers.

2. A carburetor as claimed in claim 1 wherein:

the internal configuration of said primary amplifier is such that a major portion of the fuel received at its power input is directed to its second outlet during periods of engine idling when the pressure sensed in said cylinder is at its maximum, a minor portion being directed to the first power outlet of said first amplifier; and

said primary amplifier directing proportionately more of said fuel to its first power outlet as the pressure in said cylinder decreases.

3. A carburetor as claimed in claim 2 wherein fuel flow into said first secondary amplifier is divided and flows out its first and second power outputs during periods of engine idle, said carburetor further including:

a throttle valve in said cylinder;

said second means including a fluid passage connecting the second power outlet of said first secondary amplifier to said cylinder downstream of said throttle valve; and

idle adjusting means for controlling the flow of fluid through said passage.

4. A carburetor as claimed in claim 3 wherein said first secondary fluid amplifier includes a third power outlet, said power outlets being positioned with respect to the power input and control input whereby more fuel is delivered to said second and said third power outputs as pressure in said cylinder decreases.

5. A carburetor as claimed in claim 3 and further comprising:

a second control input for said second secondary amplifier;

and

further means for applying a signal to said second control input.

6. A carburetor as claimed in claim 5 wherein said further means comprises a fluid passage means terminating at an opening in said cylinder, and pressure regulating means in said fluid assa e means.

7. car uretor as claimed in claim 5 wherein said further means comprise a normally closed fluid valve, and means mechanically linked with said throttle valve for operating said fluid valve, said fluid valve, when operated, connecting said second control input to the atmosphere.

8. A carburetor as claimed in claim 5 wherein said further means comprise means for sensing the pressure downstream from said throttle valve, and valve means responsive to said last named means for connecting said second control input to the atmosphere.

9. A carburetor as claimed in claim 5 and further comprising:

a source of fuel;

means connecting said source to the power input of said primary amplifier; and

means connected to said first power outputs of said secondary amplifiers for returning fuel to said source.

Claims

1. A carburetor for an internal Combustion engine, said carburetor comprising: a primary fluid amplifier through which all fuel must flow to reach said engine; said primary fluid amplifier having a power input for receiving said fuel, first and second power outlets, and a control input for selectively proportioning the fuel received at said power input between said power outlets; first and second secondary fluid amplifiers, said secondary amplifiers each having a power input, first and second power outlets, and a control input for selectively proportioning fuel received at said power input between said power outlets; first means connecting the first and second power outlets of said primary amplifier to the power inputs of said first and second secondary amplifiers, respectively; a cylinder; second means connecting the second power outlet of each secondary amplifier to said cylinder; and third means for sensing the pressure in said cylinder and conveying an indication of said pressure to the control inputs of said primary amplifier and said secondary amplifiers.

2. A carburetor as claimed in claim 1 wherein: the internal configuration of said primary amplifier is such that a major portion of the fuel received at its power input is directed to its second outlet during periods of engine idling when the pressure sensed in said cylinder is at its maximum, a minor portion being directed to the first power outlet of said first amplifier; and said primary amplifier directing proportionately more of said fuel to its first power outlet as the pressure in said cylinder decreases.

3. A carburetor as claimed in claim 2 wherein fuel flow into said first secondary amplifier is divided and flows out its first and second power outputs during periods of engine idle, said carburetor further including: a throttle valve in said cylinder; said second means including a fluid passage connecting the second power outlet of said first secondary amplifier to said cylinder downstream of said throttle valve; and idle adjusting means for controlling the flow of fluid through said passage.

5. A carburetor as claimed in claim 3 and further comprising: a second control input for said second secondary amplifier; and further means for applying a signal to said second control input.

6. A carburetor as claimed in claim 5 wherein said further means comprises a fluid passage means terminating at an opening in said cylinder, and pressure regulating means in said fluid passage means.

7. A carburetor as claimed in claim 5 wherein said further means comprise a normally closed fluid valve, and means mechanically linked with said throttle valve for operating said fluid valve, said fluid valve, when operated, connecting said second control input to the atmosphere.

9. A carburetor as claimed in claim 5 and further comprising: a source of fuel; means connecting said source to the power input of said primary amplifier; and means connected to said first power outputs of said secondary amplifiers for returning fuel to said source.