US1687793A - Liquid-fuel-feed system - Google Patents

Description

Oct. 16, 1928.

J. P. REMINGTON LIQUID FUEL FEED SYSTEM Original Filed Oct. 17. 1921 FICi I.

WITNESSES:

ATTORNEYS.

Patented Oct. 16, 1928.

UNITED STATES- J'OSEPH PERCY REMINGTON, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO REM- PATENT OFFICE.

INGTON MANUFACTURING COMPANY, or PHILAD LPHIA,'rENNsYLvANm, a

CORPORATION OF PENNSYLVANIA.

LIQUID-FUEL-FEED SYSTEM.

' Application filed October 17, 1921, Serial mobile is standin to which gravity systems are liable, throug leakage at the carbureter needle valve; the failure'of vacuum systems to furnish sufficient fuel at the very times when adequate supply is most imperative, when running at high speed and in hill climbing; and difliculty with the fuel supply owing to slight leakage of air from the system, as in tank pressure systems. While I prefer to feed the fuel under pressure, I am able to accomplish this without the necessity of maintaining pressure in the supply tank.

Other objects and attendant advantages of my invention will become readily apparent from the detailed description which follows:

In the drawings, Fig. I is av more or less diagrammatic illustration of an automobile fuel feeding system conventionally embody- I ing my invention.

Fig. II is a'longitudinal sectional view of a deivce for feeding the fuel from the supply tank to the carbureter and controlling the flow of fuel.

Fig. III is a horizontalsection of the pump taken as indicated by the line I IIIII in Fig. II.

In the fuel feeding system illustrated in Fig. I, the fuel storage or supply tank is conventionally represented at 1, and the carbureter at 2. Between the tank 1 and the carbureter 2, interposed in the pipe conduit comprising the sections 3 and 4, is a device 5 for feeding fuel and controlling its flow. This device 5 is connected by a pipe (3 with means capable of producing alternate impulses of rarification andcompression of the air in said pipe, here shown as an impelleror pulsator 7. This impeller or pulsator 7 comprises a cylinder 8 and a reciprocatory piston 9 which may be actuated by any appropriate means, preferably the cam shaft of the motorv to which fuel is to be supplied. As described hereinafter, the pul- Ne. 508,076. Renewed September 24; 1927.

I sator 7 and the device 5 cooperate as a pump in feeding the fuel under pressure, and the device 5 may also include means for regulating its pressure and flow. 1'

By reference to the larger illustrations,

'Figs. ,II and III of the drawings,'it will be seen that the device 5 comprises two up- 'right,'cyl indrical chambers 10 and 1 1, the former of which I will term a pump chamber, and the latter a pressure chamber for reasons which will presently become manifest. These chambers 10, 11 are formed by cavities or cups 12 and 13 in a common basemember 14 and removable caps or domes 15 and 16 screwed into enlarged brim flanges 17 and.18 of said cup cavities. The dome 15 has a screw threaded axial extension. or nipple 19 for attachment of the coupling 20 of the pipe 6 to the impeller or pulsator 7 The cup 12 of the .chamber 10 is similarly provided with an axial extension or nipple 21 for the attachment of the pipe conduit section 3 from the fuel supply tank 1.- Central stand 'pipe 22 in the chamber 10 (forming, in effect, an inward extension of the pipe line 3) serves as ameans of trapping a portion of the fuel drawn into said chamber during the suction strokes of the impeller or pulsator 7, as hereinafter explained. The displacement of the impeller or pu lsator 7 is, in practice, made such that suflicienbfuel is drawn from the tank 1 at each suction stroke to substantially fill the pipe line 3 and the chamber 10. Near its top, the stand pipe 22 is pierced with a series of apertures 23 for the passage of the fuel. The pipe 22 is almost wholly surrounded by a filtering screen 25 consisting of a cylinder of fine wire gauze, which at its bottom, is held concentrically spaced about the pipe 22 by an attached ferrule 26, and at its top by a cap piece 27 which closes the top of said pipe 25. e The cap piece 27, it will be perceived, extends to a point below the level of the apertures 23, so that the V stream of incoming fuel is directed downwardly and prevented from splashing up ward into the pipe 6 leading to the impeller or pulsator.7. Upon removal of the dome 15, the filtering screen 25 may be readily withdrawn'for cleaning when necessary.

The cups 12 and 13 of the base member 14 are joined by a Web 29, and communicate through a duct in said web. This duct the chamber 11 has a depending extension or nipple which serves for the attachment of the coupling 36 of the pipe conduit section 4 leading to the carbureter 2. In order that the pump device 5 may be readily secured to the dash board or other fixture of the automobile, the base member 14 is provided with integral extensions or wings 37-37 which are appropriately slotted as at 3838 for screws or any other convenient securing means.

The operation is as follows:

During the first suction stroke of the pump impeller or pulsator 7, fuel is drawn from the supply tank 1 through theconstantl open conduit 3 and 'into the chamber 10. uring the succeeding pressure stroke, fuel that has been drawn in by the suction is forced through the duct 30, past the valve 33, into the chamber 11, whence it flows to the carbureter 2.. If the carbureter 2 is entirely empty at starting, a few strokes may be required to expel air from the system through the carbureter, and to fill or charge the system (particularly the carbureter) with fuel. Upon closure of the ,needle valve controlling fuel admission to the carbureter 2 (by the accumulation of fuel in the carbureter) the succeeding pressure stroke or strokes of the pulsator 7 can still pass fuel through the check-valve 33 into the chamber 11 and accumulate it there; but this can go on only until the resulting pressure of the air entrapped and confined in the 'dome 16 substantially balances the pressure impulses fromthe pulsa or. Accordingly, the building upof pressure in the system is limited'by the fact that flow of fuel Via the pipe 22 is absolutely free and unrestricted, so that fuel (and even air) from aboye the stand-pipe apertures 23 can always .return through the supply conduit 3 to the tank 1, relieving any excess pressure due to the pulsator 7. In practice, the pres sure maintained in the chamber 11 depends on the displacement of the impeller or pulsator 7; and I prefer to so proportion this that a substantially constant pressure in the neighborhood of two pounds is maintained aid chamber s soon as the carbureter needle valve pens again, even slightly, fuel will flow I from the chamber 11 into the carbureter 2 under the accumulated air pressure in said chamber 11. The next pressure stroke of the pulsator 7 will then force fuel'from the pump chamber 10 into the pressure chamber 11, and thence (if the needle valve still remains open) into the carbureter 2; while during the succeeding suction stroke, fuel drawn from the tank 1 will replace. what has been injected into the carbureter. Such action will continue and recur so long as and whenever the carbureter needle valve is open.

From this'it will be seen that while fuel is surged to and fro (or at least inward) in the supply conduit comprising the pipe line 3 and the pump chamber 10 at every double stroke (suction and pressure) of the pulsator'7, yet it is only as and when permitted by the carbureter regulation'that the pressure impulses unseat the check-valve 33 and feed fuel through the delivery connection including the passage 30 and the chamber 11: i. e., only when-the outflow from the carbureter under the demand for fuel (as represented by opening of the carbureter needle valve) reduces the back-pressure in the chamber 11 that is maintained by the needle valve when closed. When the carbureter 2 is full, the pump automatically ceases to be operative, except for idle surging of fuel; when the carbureter is taking fuel, the pump becomes operative, and the surging'ceases to be idle, only to the extent of the demand. Any excess of the charge drawn into the chamber 10 on one suction stroke over the current requirements is always permitted to return through the supply line 3 on the succeeding pressure stroke.

It will be seen, therefore, that by reason of the absence of the usual check-valve or the like fromthe supply line 3, it is practicable to use an impeller or pulsator of sufficient displacement'to feed a quantity of fuel exceeding any possible requirements, without incurring any substantial variation in the pressure under which the fuel is fed.

This delivery of fuel even with the conduit open toward the supply, without any check against return of excess fuel, is made possible by energetic inward surging of the fuel. under rapid alternations of suction and pressure, such as results from actuation ot' the pulsator 7 from an automobile engine as described above. For when the pulsator 7 reverses at the end of a suction stroke and begins to exert pressure on the fuel through the elastic fluid cushion in the pipe 6, etc, the inertia of the body of liquid in the supply line 3 serves as a check-valve to allow the pressure to force the liquid'out through the check-valve 33 in the delivery (if conditions in the chamber 11 permit) ,--by virtue of the energy of the inward surge offuel induced by the precedingsuction stroke, as well as of the energy due to the succ eding pressure inpulse. And since these efle is increase in an ever-increasing proportion with the speed of the engine and the frequency With the stand-pipe 22 in the pump chamber 10, moreover, an adequate delivery of fuel at even the slowest speeds (as in cranking by hand) is safely assured by the trapping of fuel in the chamber 10. For while the chamber is substantially filled through the pipe 22 at each suction stroke, yet on the succeeding pressure stroke the fuel below the holes 23 cannot start to return, but tends to pass out through the check-valve 33 the very instant that pressure makes itself felt in the chamber.

It is further to be remarlfied that notwithstanding the periodicity of the fuel delivery by the pump, the feeding of fuel to the carbureter 2 is not intermittent, but continuous, owing to the air pressure head or cushion at all times maintained above the fuel in the chamber 11, which causes the fuel to flow to the carbureter in a steady stream so long as the needle valve remains open. And besides equalizing the flow of fuel to the carburetor 2, the elastic cushion afforded the liquid in the delivery connection by this chamber 11 absorbs the momentary peaks of the delivery pressure impulses from the pump, and thus cooperates With the free return of liquid through the supply line 3 in maintaining a substantially constant and limited delivery pressure,well below any value that might overpower the .carbureterregulation, force open the needle valve, and flood the carbureter 2 with a supply exceeding the real demand for fuel.

As regards the elastic fluid cushion through which the pulsator 7 acts on the liquid fuel, it is to be noted that with the supply tank 1 below the pump device 5, as shown, preponderance of vacuum such as would cause fuel to rise excessively highin the pump chamber 10 cannot occur, because the displacement on the pressure stroke of the pulsator 7 cannot exceed that on the suction stroke. On the other hand, preponderance of the pressure stroke arising from leakage of external air into the system at the pulsator 7, or the pipe lines or connections, is always automatically corrected by expulsion of such air from the chamber .10 into the chamber 11 and its ultimate discharge into the air chamber of the carbureter 2, which is open to the atmosphere.

When a pressure of 2 lbs. is maintained on the surface of the fuel in the chamber 11, as hereinbefore described, the conditions for the feed of fuel are exactly the same as when the standard pressure of 2 lbs. is maintained on the surface of the fuel in the supply tank of a pressure feed systeml'such as heretofore used. For such parity of! operating conditlons, my system only-requires a pressure of 2 lbs. to be raised in a chamber of a few cubic inches capacity, which can be done in a few turns of the engine; whereas the other type of system requires 2 lbs: pressure to be built up in a large fuel tank,-which may be nearly empty at starting. My system is, therefore, much quicker and more efficient in starting than a tank pressure system: indeed, with the parts proportioned, as hereinbefore described, to maintain 2 lbs. pressure in the chamber 11, an ordinary carburetor can b filled in from 5 to 10 seconds.

Inasmuch as the pulsator 7 is actuated from the cam shaft of the engine at onehalf the speed of the crank shaft, the range of variation of the impeller speed is from Bl I about strokes per minute during cranking by hand to about 1500 for full speed of the engine,-or in the ratio'of 1 to 100. Assuming acar travelling 10 miles per gallon of fuel consumed, its requirement would be 6 gallons per hour for steady operation at a speed of miles per hour, and almost twice this during rapid acceleration,as when the throttle is suddenly opened at a speed of 5 miles per hour and held open until maximum speed is reached,-since under this condition the charge is taken into the engine at atmospheric pressure, and the load is a maximum. Assuming that the motor needs 10 gal. per hour at the 3000 R. P. Mfspeed, its requirement at 300 ,B. P. M., as in idling would apparently be just as much, or 1 gal. per hour. However, the motor is unloaded in idling, and only takes in about of its piston displacement (owing to the 20 in. vacuum then existing in the intake manifold) at each intake stroke; hence it would actually use only gal. in idling.

Besides the extreme range of the variations of speed and of the fuel requirements indicated above, there is the extreme abruptness of the variation in fuel demand represented by instant opening of the throttle of an idling engine. In other words, the fuel supply needs to be increased thirty-fold on the instant; yet the pressure under which it is fed must remain approximately the same. These extreme requirements I am enabled .to meet by virtue of the unchecked return of excess fuel permitted by the absence of the usual valves or the like from the supply line. This, as already mentioned, allows a pulsator 7 of suflicient displacement to feed the requisite quantity in excess of any possible requirements to be employed, yet obviates excessive fuel supply at any time and prevents substantial variation of pressure under even the most extreme variations in operating conditions,as between high speed, when the carbureter needle valve is open most of the time, and idling, when the mg fuel, as required by the demand, even with the conduit substantially open at the supply side of the check-valve means; and permitting fuel in excess of the requirements that is drawn inward by the suction to return through the conduit under the pressure.

2. A method of feeding liquid fuel under pressure, in amounts adapted to varying demand, in a conduit unchecked as against return of excess fuel, but with check-valved delivery; which method comprises exerting sufficiently rapid alternations of suction and pressure-on the liquid in said conduit to surge the same inward under the suction impulses with sutficient energy to enable delivery to be made under the pressure impulses, by virtue of the energy of the lDCOl11- ing fuel, as required by the demand, even with the conduit substantially open at the supply side of the check-valve means; permitting fuel in the excess of the requirements that is drawn inward by the suction to return through the conduit under the pressure, and'at each passage of fuel through the check-valve means also trapping fuel at the supdply side thereof against return as aforesa1 i 3. A method of feeding liquid fuel under pressure through a check-valved feed conduit to a carburetor with regulated admission, in amounts adapted to varying demand; which method comprises exerting sufliciently rapid alternations of suction and pressure on the liquid at the supply side of the checkvalve means, through an elastic fluid cushion, to surge the fuel inward in the conduit under the suction impulses with sufficient energy to enable delivery to be made, by virtue of the inertia of the incoming fuel, when permitted by the carbureter regulation, even with said conduit substantially open toward the supply; and elastically cushioning the liquid in the delivery connection to the carbureter and thereby safe-guarding the latter against flooding by the pressure 1mpulses.

4:. The processes of conveying liquid fuel from a source of supply to a point of use through a system comprising a chamber amounts of use, even with the inlet substantially open;

and permitting the remainder of the charges to return through the inlet.

5. A method of feeding liquid fuel under pressure to a motor vehicle engine, in adapted to varying demand, through a system comprising a check-valved feed conduit with a confined body of elastic fluid maintained in contact with the liquid fuel at the supply side of the check-valve means; which method comprises exerting alternations of suction and pressure on the elastic fluid, with a frequency proportional to the speed of the engine, and thereby surging the fuel inward in said conduit with corresponding frequency, so that the varying inertia of fuel in the supply end of the conduit for varying frequencies. of alternation enables fuel which is drawn inward by the I suction to be passed through the check-valve means under the pressure, as required by the varying demand, even with the conduit substant'ally open at the supply side of the check-valve means; and permitting fuel in excess of the requirements that is drawn inward as aforesaid to return through the conduit under the pressure.

6. A system of the character described for feeding liquid fuel under pressure, selfadapting to varying demand; said system comprising a substantially closed checkvalved feed conduit, with a confined body of elastic fluid in contact with the liquid fuel therein at the supply side of the check-valve means, and means for exerting alternate suction and pressure on the elastic fluid and thereby surging fuel in the conduit; said conduit remaining open at the supply s de of its check valve means to permit surging back and forth therein during periods 2f low demand, and the inertia of the fuel in the supply end of the conduit enabling delivery to be made throughsaid check-valve means under the pressure impulses, even with the conduit open.

7. A system for feeding liquid fuel under pressure, substantially closed from fuel supply to fuel delivery, and self-adapting, as hereinafter described, to variations 1n the demand for fuel; said system comprising a a pump with means of producing alternate suction and compression; a check-valved delivery from said pump; a fuel supply ill] conduit to said pump permitting return, under the pressure stroke of the pump during periods of low fuel demand, of fuel in excess of the demand that has been drawn into the pump by the suction; and means for trapping in the pump a portion of the fuel drawn in as aforesaid, to prevent its return; the inertia of fuel in the supply conduit enabling the pump to deliver under pressure without closure of said conduit, and the return of fuel as aforesaid preventing excessive pressure when the demand falls below the potential pump capacity.

8. A fuel pump comprising a pumping chamber containing gas, means for causmg alternate compression and rarefaction of said gas, an outlet passage from said chamber having therein a check-valve, means to restrict the outflow through said valve at times to less than the maximum capacity of the pump, and an inlet conduit connecting said chamber to a source of supply, said conduit being open to permit the liquid en-' tering said chamber in excess of the permitted outflow to surge back through the said c onduit under the influence of the compression of the gas, the discharge checkvalve being constructed and arranged to 7 open under the compression stroke by reason of the inertia of the inflowing liquid, without closure of the inlet conduit.

9. A system for feeding liquid fuel under pressure to a motor vehicle engine, selfadapting, as hereinafter described. to variations in the demand for fuel, and comprising a pump with an elastic fluid pulsator, driven by the engine for producing alternate suction and compression, a check-valved delivery from said pump, and a fuel supply conduit to said pump permitting return, under the pressure stroke of the pump during periods of low demand, of fuel in excess of the demand that has been drawn into the pump by the suction; the inertia of fuel in the supply conduit enabling the pump to deliver under pressure without closure of said conduit, and the return of fuel as aforesaid preventing excessive pressure when the demand falls below the potential pump capacity.

10. A fuel supply system of the character described comprising a carbureter and its fuel admission valve, a pumping chamber with delivery connection to said carbureter, an elastic fluid pulsator for producing-alternations of suction and compression in said chamber, and a fuel conduit from the source of supply to said pump chamber which 'is open during normal functioning of the device to permit back flow of liquid whenever the resistance to outflow through the delive 'y connection into the carbureter exceeds the operating resistance to such back flow. I

11. A pressure-feedmg fuel supply system it inward under the suction impulses with sufficient energy to enable delivery to be made under the pressure impulses, when permitted by the carbureter valve regulation, even with said conduit substantially open toward the supply.

12. A pressure-feeding liquid fuel supply system comprising, in combination with a carbureter and its fuel admission valve, a

conduit leading to the carbureter from the supply unchecked as againstreturn of excess fuel; an elastic fluid pulsator for exertmg sufficiently rapid alternations of suction and pressure on the liquid to surge it inward under the suction impulses with sufficient energy to enable delivery to be made under the pressure impulses, when permitted by the carbureter valveregulation, even with said ,conduit substantially open toward the supply; and a check-valve in the delivery connecti n of said conduit to the carbureter adapted to remain closed under the back-pressure maintained by the carbureter valve when closed, and to pass the fluid to the carbureter under the pulsator impulses when the carbureter valve is open.

13. A pressure-feeding liquid fuel supply system-comprising, in combination with ,a carbureter and its fuel admission valve, a conduit leading to the carbureter from the supply unchecked as against return of excess fuel; an elastic fluid pulsator for exerting sufiiciently rapid alternations of suction and pressure on the liquid to surge it inward under the suction impulses with sufficient energy to enable delivery to be made under the pressure impulses, when permitted by the carbureter valve regulation, even with said conduit. substantially open toward the supply; and a check-valve in the delivery connection of said conduit to the carbureter, with means affording an elastic cushion for the liquid in said connection and thereby safeguarding the carbureter against flooding by the pressure impulses.

14. A pressure-feeding fuel supply system comprising, in combination with, a carbureter and its fuel admission valve, a pump with a motor-driven elastic fluid pulsator for producing'alternate suction and compression and a fuel supply connection unchecked as against return of excess fuel, and a delivery connection to the carbureter with a pressure chamber and a check-valve; so that on the pressure strokes fuel may flow from the pump toward the supply as well as toward the carbureter, and flooding of the latter by the pressure impulses may be prevented. V

15. A system of the character described for feeding liquid fuel under pressure in a substantially continuous flow, self adapting', as hereinafter described, to variations in the demand; said system comprising a substantially closed check-valved feed conduit with an elastic fluid cushion at the supply side of its check-valve means, a pressure chamber beyond said check-valve means, and means beyond said pressure chamber for controlling the delivery from said conduit according to demand, so that back-pressure may be imposed on the fuel; and means for producing sufliciently rapid alternations of suction and pressure impulses on the fuel at the supply side of 'said check-valve means through said cushion to surge the fuel inward in said conduit with such energy that the inertia of the fuel in the supply end of the conduit enables delivery to be made through said check-valve means, even with the conduit substantially open at the supply,

side of said check-Valve means, whenever flow from said chamber under the demand has reduced the pressure therein below that due to the pressure impulses.

16. A fuel supply system for a motor ve- 1,es7,7es a hicle engine comprising a carburetor with means for controlling the admission of fuel thereto according to the demand, so that back pressure may be imposed on the fuel; a pump with an elastic fluid pulsator for producing alternate suction and pressure impulses, in frequency proportional to the speed of the engine; a cheek-valved delivery connection from said pump to said carburetor, provided with a pressure chamber beyond its check-valve means; and a fuel supply conduit to said pump permitting return therethrough, under the pressure stroke of .the pump during periods of low fuel demand, of fuel in excess of the demand that has been drawn intothe pump by the suction; the inertia of the fuel in the conduit enabling delivery to be made through said check-valve means under the pressure impulses, even with the supply conduit open, whenever flow from said chamber under the demand has reduced the pressure in said chamber below that due to said pressure impulses.

In testimony whereof, I have hereunto signed my name at Philadelphia, Pennsylvania, this 29th day of September, 1921.

JOSEPH PERCY REMINGTON.

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