US2985159A

US2985159A - Cold starting means for carburetors

Info

Publication number: US2985159A
Application number: US682798A
Authority: US
Inventors: James T W Moseley
Original assignee: Holley Carburetor Co
Current assignee: Holley Performance Products Inc
Priority date: 1957-09-09
Filing date: 1957-09-09
Publication date: 1961-05-23
Anticipated expiration: 1978-05-23

Description

May 23, 1961 J. T. w. MOSELEY 2,985,159

GOLD STARTING MEANS FOR CARBURETORS Filed Sept. 9, 1957 2 Sheets-Sheet 1 I4 C 46 6W u l8 r- 1 2 52 I6 v 54 FUEL GASO- PUMP TANK 1 INVENTOR. 56 42 3O JAMES T.W. MO 5 ELEY 58 Fl 6.6.

34 v 36 ATTOR EYS May 23, 1961 J. T. W; MOSELEY COLD STARTING MEANS FOR CARBURETORS Filed Sept. 9, 1957 2 Sheets-Sheet 2 FIGQ 98 78 80 I0 f; 4 70 lo 48 1 5 28 4O 44 n 2 I26 4 W ll l '2 L h I no I20 I d 24 82 2 I18 FIGS INVENTOR.

JAMES T.W.MOSELEY BY COLD STARTING MEANS FOR CARBURETORS James T. W. Moseley, Grosse Pointe Park, Mich., assignor to Holley Carburetor Company, Van Dyke, Mich., a corporation of Michigan Filed Sept. 9, 1957, Ser. No. 682,798

20 Claims. (Cl. 123-119) This invention relates generally to carburetors and more specifically to means within the carburetor for decreasing the engine cranking time during the starting period.

Present carburetors are generally comprised of an air intake passage, a throttle body having throttle valves controlling the air intake passage, a fuel bowl and a float controlled valve determining the amount of fuel within said bowl. The problem which exists with this general structure is that when the engine has been shut down after it has attained operating temperature, excmsive amounts of heat are absorbed by the fuel bowl and surrounding structures. This excessive heat causes the fuel within the bowl to evaporate thereby boiling off the more volatile hydrocarbons and leaving only the low hydrocarbons.

This problem becomes more acute during cold weather because the fuel is made more highly volatile during that season. The result is that the same quantity of heat removes a greater amount of high hydrocarbons and leaves very little if any fuel within the fuel bowl. fore, after the engine has been shut down for a period of time there is no fuel of sufficient volatility to start the engine. This necessitates prolonged cranking of the engine until fresh fuel can be pumped, filling the fuel bowl.

An object of this invention is to provide means which will eliminate this excessive engine cranking when starting after a hot shut down.

More specifically, the object of this invention is to provide means which will automatically and instantaneously provide the engine with fresh fuel during the starting period.

Other objects and features of the invention Will be come apparent as the description proceeds, especially when taken in conjunction with the accompanying drawing, illustrating preferred embodiments of the invention, wherein:

Figure l is a side elevational view of a carburetor embodying the invention and having the fuel bowl sectioned.

Figure 2 is a front elevational view of the carburetor shown in Figure 1, with parts in section on line 2-2, Figure 1.

Figure 3 is a modification of the outlet nozzle shown in Figures 1 and 2.

Figure 4 is a modification of the invention.

Figure 5 is another modification of the invention.

Figure 6 is an enlargement of a portion of Figure 2, showing the starting chamber.

Referring in greater detail to the drawings, a carburetor 10 has a body 11, an induction passage 12, throttle valve 13 controlling the flow through said induction passage,

Therenited States Patent 0 i Patented May 23, 1961 at 36. A spring 38 is mounted within the fuel bowl directly below the float so that it increases the floats buoyancy. The arm 34 is in contact with needle 40 of valve assembly 30 and moves the needle which is slidable within body 42 according to the position of the float 32.

A generally cup-like structure 44 is secured to the body 42 of valve assembly 30 in such a manner as to perfect a seal about said body at the lower portion of the cup, and has its open end extending upwardly. A conduit 46 has one end within the air passage 12 of the carburetor and has its other end in communication with the chamber 48 formed generally by the cup 44. An adaptor plug 52 having a filter screen 54 secured to it supplies fuel to conduit 28 from the fuel tank. Fuel from the tank is supplied to the bowl by a fuel pump which ordinarily is actuated only when the engine is turning over as an incident to cranking, or is running.

Operation of invention as shown in Figures 1, 2 and 3 When the engine is shut down after it has reached normal operating temperatures, the heat Which has accumulated within the surrounding engine structure is trapped within the engine compartment. This causes the fuel bowl and fuel therein to rise to a temperature which results in the boiling off of the highly volatile hydrocarbons. The gasoline which remains in the fuel bowl, if any at all, does not have enough hydrocarbons of sufficiently high volatility to restart the engine.

Assume that the engine has been shut down and the fuel bowl in the carburetor as shown in Figures 1 and 2 is almost completely dry, and that the thermostat 16 has closed the choke valve 14. Under these conditions the float 32 will have moved counterclockwise about pivot 36 causing needle valve 40 to move away from its seat.

When the engine is cranked, the fuel pump will deliver fuel from the tank, through the filter 54 and into conduit 28. Needle valve 40, being off of its seat, allows fuel to pass through the valve 30 and out through the orifice 56, of which there may be one or more in body 42. The fresh fuel being thus pumped through orifice 56, fills chamber 48 which is in communication with the intake end 58 of conduit 46. The manifold vacuum caused by the cranking of the engine draws the fuel into conduit 46 and out through its nozzle end 60 into the induction passage 12. The rate of fuel flow being greater from the fuel pump than through conduit 46, cause the chamber g8 to fill rapidly and spill over thereby filling the fuel owl.

The foregoing description of operation was based on the assumption that hot percolation had completely emptied the fuel bowl 18. In many cases, the fuel bowl is not completely emptied, and in this condition the difficulty and delay in starting may be even worse than when the bowl is emptied. If the bowl is empty, the delay in starting is only that required to deliver a new supply of full content fuel to the bowl and allow it to be drawn through the usual jet and well into the air induction passage. But if the bowl contains a substantial quantity of fuel from which the more volatile fractions have been driven off by hot percolation, the fuel in the bowl may resist ignition and starting will not occur. In addition, the fresh fuel delivered by the fuel pump which contains the volatile fractions facilitating ignition, will not be available as such, but instead are diluted by the low boiling point fuel fractions remaining in the bowl. The continued inflow of fresh fuel will eventually enrich the mixture in the bowl with suflicient volatile fractions to perrnit starting. Thus, a longer delay than when the bowl is dry may be entailed.

The present invention also takes care of this eventuality, since the fresh fuel is not delivered to the bowl to be mixed with and diluted by the fuel therein from which the volatile fractions have been removed. Instead, a supply of the fresh fuel is set apart for delivery directly to the air induction passage 12.

' It will further be noted that delivery of fresh fuel from the chamber 48 is to the air induction passage between the choke valve 14 and throttle plate 13, so that the fresh starting fuel is drawn through conduit 46 only during starting while the engine is choked. After starting when the choke valve is opened, fuel does not flow through conduit 46, and all of the fuel passing valve 30 spills over the top of cup 44 into the fuel bowl.

Figure 3 is a modification of the nozzle end 60 of the conduit 46. The nozzle end 6ll-A of Figure 3 is bent as shown and protrudes into the induction passage 62. Its end is also beveled so that the port at the end thereof faces partly downstream.

Modification of Figure 4 Figure 4 is a modification of the invention; all of the details which are alike or similar to those in Figures 1 and 2 are identified with like numerals. The carburetor 10 in Figure 4 also illustrates main and idle fuel metering systems as shown by

passages

64, 66 and 68, and main nozzle 70 and idle nozzles 72.

A passage 74 leads from chamber 4-8 to a chamber 76 having an orifice 78 adapted to be controlled by a valve 80. A conduit 82 communicates with port 78 and extends into the induction passage 12.

The position of valve 88 is controlled by a pressure responsive diaphragm assembly which 'is substantially comprised of

housings

84 and 86 between which a diaphragm 88 is suitably secured. The valve 80 is secured to the diaphragm through a stem portion '90. A spring 92 is placed within chamber 94, formed by housing 86 and diaphragm 88, and normally biases the diaphragm and valve downwardly. Chamber 94 communicates with the intake manifold 22 by means of conduit 96 while chamber 98 is vented to the atmosphere through port 100.

This modification operates in the same general manner as disclosed in Figures 1 and 2; however, the modification includes automatic means for positively shutting ofl the fuel flow through the auxiliary conduit means after the engine has started.

During engine cranking, the manifold vacuum will draw fresh fuel from chamber 48 up through conduit 82 and into the induction passage 12. However, because of the calibration of spring 92 there is not a sufiicient pressure differential across diaphragm 88 to move said diaphragm and valve 80 against the spring.

When the engine becomes self sustaining, the manifold vacuum will rise to a value causing a suflicient pressure difierential across diaphragm 88 which will move sit against the force of spring 92 and shut the fuel flow off through conduit 82.

Modification of Figure Figure 5 is another modification of the invention. This modification substitutes mechanical means instead of the pressure responsive means of Figure 4 for shutting off the fuel flow through the auxiliary conduits after the engine has started. The details which are alike or similar to those in Figures 1, 2 and 4 are identified with like numerals.

Port 78 is controlled by valve 80' whose position is determined by a cam 110 rigidly secured to the choke shaft 112. A chamber 114 communicating with orifice 78 and conduit 82, contains a generally cylindrical guide member 116 and spring 1 18 biasing the guide member upwardly. A plunger portion 128 is connected to valve 80 through the guide member 116 and a stem 122. A lever 124, pivoted at some fixed point 126 operatively engages the plunger 120 and cam 110 simultaneously.

On starting, the choke valve 14 will be in a closed position thereby rotating the cam 110 counterclockwise from the illustrated position, and causing the lever 124 to also rotate counterclockwise. This will in turn depress plunger 1211 thereby pushing the valve 80 off of its seat in port 78. The fresh fuel will be drawn from chamber 48 (Figure 4) through passage 74, port 78, conduit 82 and into the induction passage 12. When the engine becomes self-sustaining and the choke moved a certain number of degrees clockwise, the cam 110 would allow the spring .118 to move the plunger 120 and valve 80 upwardly thereby rotating lever 124 clockwise and positively shutting off the flow of fresh fuel through orifice 78.

The drawings and the foregoing specification constitute a description of the improved cold starting means for carburetors in such full, clear, concise and exact terms as to enable any person skilled in the art to practice the invention, the scope of which is indicated by the appended claims.

What I claim as my invention is:

1. In an internal combustion engine having a fuel pump, a carburetor including a fuel bowl and an air induction passage, the improvement which comprises means for intercepting fresh fuel delivered by the fuel pump before it reaches the fuel bowl, means for delivering said intercepted fuel to the air induction passage during cranking of the engine, and means for terminating said delivery of fuel to said air induction passage when the engine starts.

2. Cold start means for an internal combustion engine having a fuel pump connected to a carburetor fuel bowl and an air induction passage comprising means responsive to cranking of the engine for passing fresh fuel from the pump to the air induction passage without allowing mixing of any of said fresh fuel with fuel in the carburetor fuel bowl.

3. Cold start means for an internal combustion engine having a fuel pump connected to a carburetor fuel bowl and an air induction passage comprising means responsive to cranking of the engine for bypassing fresh fuel from the pump around the carburetor bowl to the air induction passage, and means responsive to starting of the engine to terminate such bypass delivery of fuel to the air induction passage.

4. A cold start carburetor comprising an air induction passage and a fuel bowl of substantial volumetric capacity having a valved fuel supply passage connecting to the interior thereof and adapted to be connected to a fuel pump, a container of relatively small volumetric capacity in said bowl in position to receive fuel delivered through said valved passage and to deliver only overflow fuel to said bowl, and a fuel supply passage having an intake port in said container and a discharge port in said air induction passage.

5. A cold start system for delivering fuel to an air induction passage of an internal combustion engine having a choke valve and throttle plate, a fuel pump, a carburetor fuel bowl, a passage connecting said pump and bowl, a small volume container in said bowl positioned to receive fuel from said pump and to deliver overflow fuel to the interior of said bowl, said container being operable to prevent mixing of the fuel therein and the fuel in the interior of said bowl, and a fuel supply passage having an intake port in said container and a discharge port in said air induction passage downstream from said choke valve.

6. A cold start carburetor comprising an air induction passage and a fuel bowl of substantial volumetric capacity having a valved fuel supply passage connecting to the interior thereof and adapted to be connected to a fuel pump, a container of relatively small volumetric capacity in said bowl in position to receive fuel delivered through said valved passage and to deliver overflow fuel to said bowl, a fuel supply passage having an intake port in said container and a discharge port in said air induction passage, and means responsive to starting of the engine to close said fuel supply passage.

7. Structure as defined in claim 6 in which said last named means is pressure responsive and is connected to the engine manifold.

8. Structure as defined in claim 6 in which said last named means comprises cam mechanism operatively connected to said choke valve.

9. A method of starting an engine having a main fuel reservoir and carburetor with a float chamber controlled by a float valve, said method being particularly suited for starting said engine when said float chamber has boiled so as to leave a low level of less volatile fuel and comprising the steps of providing fresh volatile fuel from the main fuel reservoir completely independent of the fuel in the float chamber for starting purposes and reverting back to the fuel in the float chamber after said engine has started.

10. The method of starting an internal combustion engine having an engine operated fuel pump, a carburetor having a float controlled fuel chamber, an air induction passage, and means connecting said chamber and passage, the method comprising the step of providing a flow of fresh volatile fuel from the pump to said passage in bypassing relation to said chamber during cranking of the engine, and discontinuing such flow upon starting of the engine.

11. The method of starting an internal combustion engine having an engine operated fuel pump, a carburetor having a float controlled fuel chamber, an air induction passage, and means connecting said chamber and passage, the method comprising the step of providing a flow of fresh volatile fuel from the pump to said passage in bypassing relation to said chamber While manifold vacuum remains at a value resulting from cranking the engine, and discontinuing such flow when manifold vacuum reaches a value resulting from starting of the engine.

12. The method of starting an internal combustion engine having an engine operated fuel pump, a carburetor having a float controlled fuel chamber, an air induction passage having a choke valve and throttle plate therein, and means connecting said chamber and passage, the method comprising the step of providing a flow of fresh volatile fuel from the pump to said passage at a point downstream from said choke valve, in bypassing relation to said chamber during cranking of the engine, and discontinuing such flow upon starting of the engine.

13. The method of starting an internal combustion engine having an engine operated fuel pump, a carburetor having a float controlled fuel chamber, an air induction passage having a choke valve and throttle plate therein, and means connecting said chamber and passage, the method comprising the step of providing a flow of fresh volatile fuel from the pump to said passage at a point intermediate said choke valve and throttle plate, in bypassing relation to said chamber during cranking of the engine, and discontinuing such flow upon starting of the engine.

14. In a carburetor for an internal combustion engine having an air induction passage and a fuel bowl provided with a float valve controlled fuel inlet port adapted to be connected With a fuel pump, a chamber comprising an upwardly open cup of relatively small capacity in said bowl positioned to receive only fresh fuel delivered through said inlet port, said chamber having means for delivering overflow fuel to said bowl, and a fuel supply passage having an intake port in said chamber and a discharge port in said air induction passage.

15. In a carburetor for an internal combustion engine having an air induction passage and a fuel bowl provided with a float valve controlled fuel inlet port adapted to be connected with a fuel pump, a chamber of relatively small capacity in said bowl positioned to receive only fresh fuel delivered through said inlet port, said chamber having means for delivering overflow fuel to said bowl, a fuel supply passage having an intake port in said chamber and a discharge port in said air induction passage, valve means in said fuel supply passage, and means for closing said valve means when said engine is running.

16. In a carburetor for an internal combustion engine having an air induction passage and a fuel bowl provided with a float valve controlled fuel inlet port adapted to be connected with a fuel pump, a chamber of relatively small capacity in said bowl positioned to receive only fresh fuel delivered through said inlet port, said chamber having means for delivering overflow fuel to said bowl, a fuel supply passage having an intake port in said chamber and a discharge port in said air induction passage, valve means in said fuel supply passage, and means for closing said valve means when engine manifold reaches a predetermined value.

17. In a carburetor for an internal combustion engine having an air induction passage and a fuel bowl provided with a float valve controlled fuel inlet port adapted to be connected with a fuel pump, a chamber of relatively small capacity in said bowl positioned to receive only fresh fuel delivered through said inlet port, said chamber having means for delivering overflow fuel to said bowl, a fuel supply passage having an intake port in said chamber and a discharge port in said air induction passage, valve means in said fuel supply passage, and means for closing said valve means when the usual engine choke valve reaches a predetermined open position.

18. In a carburetor for an internal combustion engine having an air induction passage and a fuel bowl provided with a float valve controlled fuel inlet port adapted to be connected with a fuel pump, a chamber of relatively small capacity in said bowl positioned to receive fresh fuel delivered through said inlet port and maintain said fresh fuel completely separate from the fuel in said fuel bowl, said chamber having means for delivering overflow fuel to said bowl, and a fuel supply passage having an intake port in said chamber and a discharge port in said air induction passage.

19. In a carburetor for an internal combustion engine having an air induction passage and a fuel bowl provided with a float valve controlled fuel inlet port adapted to be connected with a fuel pump, a chamber of relatively small capacity in said bowl positioned to receive fresh fuel delivered through said inlet port, said chamber having means for delivering overflow fuel to said bowl, a fuel supply passage having an intake port in said chamber and a discharge port in said air induction passage, and valve means in said fuel supply passage.

20. In an internal combustion engine having a fuel pump, a carburetor including a fuel bowl and an air induction passage having a throttle valve, choke valve and venturi therein, the improvement which comprises means for intercepting fresh fuel delivered by the fuel pump before it reaches the fuel bowl, means for delivering said intercepted fuel to the air induction passage between the throttle and choke valve and outside of the venturi during cranking of the engine, and means for terminating said delivery of fuel to said air induction passage when the engine starts.

References Cited in the file of this patent UNITED STATES PATENTS 2,647,735 Haynie Aug. 4, 1953