US2195825A - Fuel system for engines - Google Patents

Description

April 2, 1940. vM Q PRICE 2,195,825

FUEL SYSTEM FOR ENGINES Filed May 11, 19.57 4 Sheets-Sheet 1 A TTORNE YS.

APl'l 2 l940- N. c. PRICE 2,195,825

FUEL SYSTEM FOR ENGINES Filed nay 11, 1937 4 sheets-sheet z 'INVENTORT Zal/'Fryk C. /ALQ April 2, l940 N. c. PRICE 2,195,825

FUEL SYSTEM FOR ENGINES Filed lay 11, 1937 4 Sheets-Sheet 3 E ig.5.

INVENTORY y BY 73M( ATTORNEYS.

April 2; 1940. I' N. c. PRlclzE Y 2,195,825'

I FUEL SYSTEH FOR ENGINES ined lay 11. 1957 sheets-sheet 4 Fig.'

Fue L Ti/ming IN VEN TOR.,

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ATTORNEYS.

Patented Apr. 2, 1940 PATENT OFFICE FUEL SYSTEM FOR ENGINES Nathan' C. Price, Berkeley, Calif., assigner to Universal Engine and Propeller Co., Alameda, Calif., a corporation of California Application May 11, 1937, Serial No. 142,001 v 9 Claims.

The present invention relates to a fuel induction system especially adapted for aircraft engmes.

The principal object of the invention is to provide a fuel induction system of the positive pressure or super-charger type in which the liquid fuel is properly proportioned to the air at all times and under all conditions of speed, load, and atmospheric pressure. A second object is to provide a system in which the air and liquid fuel are kept separate until just before entering the engine cylinder,`and in which the liquid fuel distribution lines leading to the various cylinders are housed within the air induction system,I

thereby improving vaporization of the fuel by subjecting it to the increased temperature of the air delivered by the super-charger blower, and eliminating any danger from re in the event of leakage from a fuel line. Another object is to provide a system in which the high tension ignition distributor and the conductors leading to the spark plugs of the cylinders are housed within the air induction system, thereby subjecting them to super-atmospheric pressure and pre'- venting corona discharge losses from said distributor and conductors under the conditions of reduced atmospheric pressure encountered at high altitudes.

These and other objects and advantages of the invention will become apparent from the following specication, which should be read with the understanding that changes, within the scope of the claims hereto appended, may be made in the form, construction, and arrangement of the several parts herein shown and described, without departing from the spirit of the invention as defined in said claims.

A preferred form of the invention is herein described and illustrated as embodied in an aircraft engine of theradial cylinder type. It willl be apparent, however,'that the invention can be applied to engines of other types without material change. Only such parts of the engine as are pertinent to the invention are shown and described herein.

In the drawings,

Fig. 1 is a partial rear end' elevation of an engine provided with my fuel induction system.

Fig. 2 is a part sectional front end elevation,v

enlarged, of the induction manifold.

Fig. 3 is a longitudinal section of the rear end portion of the engine taken on the line 3-3 of Fig. 1, and enlarged, showing the air blower and fuel distributor.

(Cl. 12S-119) Fig. 4 is a plan view, enlarged, of the fuel compensator.

Fig. 5 is a vertical section of the same, taken on the line 5-5 of Fig. 4.

Fig. 6 is a partial vertical section of the same, 5 taken on the line 6 6 of Fig. 4.

Fig. 7 is a part sectional side elevation of the rear end portion of the engine, showing the position of the fuel compensator with respect to the air intake and blower, the sectional portions 10 being taken in a vertical plane indicated by the line 'l-T of Fig. 1.

Fig. 8 is a diagram showing the functional arrangement of the several parts.

Throughout the following specification, the l5 word fuel will be used as meaning liquid fuel capable of being vaporized or atomized and burned in the engine cylinder when mixed in proper proportions with air and suitably compressed. The fuel may be gasolineof high Volatility, for which the particular engine herein illustrated has been designed, or it may be some other fuel of lower volatility. The invention contemplates al blower or other means for supplying air to the cylinders under super-atmospheric pressure, means for supplying fuel under constant pressure, a fuel compensator for regulating the amount of fuel supplied in proper proportion to the amount of air under all conditions of operation, and a conduit system for separatelyY conducting the air and the fuel to the intake ports of the cylinders, said fuel being sprayed into the air stream at points close to said intake ports.

Referring more particularly to the drawings, the reference numeral Il designates the main shaft of the engine, I2 is the crankcase, and I3,

Figs. 1 and 2, are the rear cylinders of two adjacent banks or rows. The number of cylinders in each bank is immaterial, as is the number of banks. All the cylinders of each two adjacent banks are served by a common intervening manifold I4 having suitably spaced branches I5 connected with the cylinder inlet ports I6. The 'exhaust manifolds and the inlet and exhaust valves of the cylinders are immaterial to the present invention, and are therefore illustrated conventionally in the diagram, Fig. 8, in which only one cylinder is shown for the sake of simplicity.

At the rear end of the engine the manifold I 4 50 turns inwardly, i. e. toward the shaft I I, and connects with a branch II leading outwardly from the discharge duct I8 of a blower I9, Fig. 3, which surrounds and is driven by the shaft II, and has an inlet chamber 20. The blower draws air in through an inlet pipe 2|, Fig. 7, having a butterfly valve 22 which is the throttle valve of the engine. It will be seen that the parts hereinbefore described constitutes an air induction system, the air being drawn in through the throttle controlled intake 2| by the blower I9, and forced out to the various cylinders, at superatmospheric pressure, through the manifold I4. There may be as many manifolds as is necessary to supply all the cylinders, each such manifold being connected as described with the common discharge duct I 8 of the blower.

Fuel is supplied at constant pressure from any suitable source, not shown, and its flow is regulated in a compensator 23 mounted at the rear of the engine as indicated in Figs. 1 and 7. This compensator, which is shown in detail in Figs. 4, 5 and 6, has a fuel regulating valve which is controlled both by the ow or velocity pressure of the air in the intake 2| and by the flow or velocity pressure of fuel itself. The fuel enters the unit through a pipe 24, and passes through a venturi throat 25, thence through the regulating valve and out through a pipe 26. The regulating valve is a plug 21, slidable in a cylinder 28. The upper end of said plug moves toward and away from a seat 29, thereby varying the ffow of fluid through the outlet 26. The valve plug 21 has a small central port 30, which is closed at its lower end by a needle formed upon the upper end of a stem 3|. A piston 32 on said stem operates in a cylinder 33. The lower end of said cylinder, below the piston 32, is open to the pressure of the fuel in the supply line, through a passage 34. The upper end of the cylinder 33, above said piston 32, communicates with the throat of the venturi through passages 35. The piston 32 is therefore affected by a pressure differential which is a function of the fuel flow, an increased flow increasing the pressure differential and tending to raise the piston, and a decreased flow tending to lower said piston. The arrangement of the ported valve plug 21 is such that it tends to keep itself seated lightly on the stem 3|, and therefore follows the movements of said stem. A needle valve 36, adjustable from the exterior, is provided to regulate the effective area of the venturi throat.

'I'he stem 3| extends downwardly through a guide bushing 31, and carries a second and larger piston 38, operating in a cylinder 39. The lower end of said cylinder 39, below the piston 38, is connected by a passage 40 and pipe 4|, Fig. 7, with the air intake 2|. The upper end of said cylinder, above the piston 38, is open to the atmosphere through a passage 42 and a screen 43, Fig. 6. The lower side of said piston 38 is thereforeexposed to the sub-atmospheric pressure in the air intake 2|, and its upper side is exposed to atmospheric pressure. Hence the piston 38 is acted on by the pressure differential existing between the air intake and the atmosphere, which is a function of the flow of air to the engine. A spring 44 tends to resist the effect of said air pressure differential.

It will be seen that the air piston 38 and the fuel piston 32 work in opposition. As the throttle 22 is opened and more air flows through the intake 2|, its pressure falls and theair piston 38 and the stem 3| move down, thereby opening the fuel valve 21 and allowing-more fuel to flow. Such increased now of fuel, however, increases the pressure differential affecting the fuel piston 32, which resists the downward movement of the stem 3|. By properly proportioning the various parts, the device can be made to regulate the fuel in proper ratio to the air supply under all conditions of the latter.

The fuel compensator provides a further automatic regulating function, to compensate for variations in atmospheric pressure due to changes in altitude. This function is accomplished by an aneroid element 45, Fig. 6, mounted in a chamber 46 and exposed to the atmosphere through an aperture 41. The upper end of said aneroid element is fixed at 48, and its lower end carries a needle valve 49 which obstructs, to a greater or less extent, the air inlet 42 leading to the air cylinder 39. The passage below the valve 49, shown at 50 in Fig. 6, is for construction purposes only, and has no operating function. 'Ihere is a constant ow of air through the passage 42, due to the pressure differential on the piston 3B and the leakage around it. As the atmospheric pressure decreases, due to altitude, the element 45 expands, causing its valve 49 to move down and further obstruct the passage 42. This reduces the flow of air through the cylinder 39, thereby reducing the effect of the sub-atmospheric pressure in the air intake 2 I, and reducing the fuel to airl ratio. Thus the proper proportions of fuel and air are automatically maintained under all conditions of throttle opening and atmospheric pressure.

From the compensator 23, the fuel passes through the pipe 26 to one or more timing and distributing Valves 26a. (Fig. 8), the number thereof depending upon the number and arrangement of the engine cylinders. The drawings herein illustrate one such timing and distributing valve, designed to distribute fuel to all cylinders of the two banks served by the air induction manifold I4.

At the rear of the engine, the crankcase is provided with a suitable extension 5I, Figs. 1 and 3, in which the fuel distributor is housed immediately behind the blower and approximately in line with the end of the manifold I4. The distributor comprises a fixed member bolted to the housing and having an annular upper head 52, Fig. 3, and a central shank 53 extending downwardly therefrom. Within the head 52 is a hardened and ground annular sleeve 54, and within said sleeve is a rotor 55 fixed upon a vertical shaft 56. A plate 51 is bolted to and. closes the top of the headl 52, said plate having an upward extension in which is mounted a ball bearing 58 for the shaft 56. 'Ihe lower end of said shaft carries a bevel gear 59, and a second ball bearing 60 is mounted between an upstanding iiange on said gear and the stationary shank 53. The two bearings 58 and 60 centralize the rotor 55 accurately within the stationary sleeve 54.

Packing 5| is provided around the shaft 58, preferably at three points, viz): the upper and lower ends of the shank 53, and in the shank of the cover plate 51. Each packing is compressed by a spring 62 held in place by a suitable retainer 63.

'Ihe head 52 and its sleeve 54 are provided with a radially disposed inlet opening 64 with which the fuel inlet pipe 26 communicates, and with a plurality of properly spaced radial discharge openings, one of which is shown at 65, said discharge openings being positioned in a horizontal plane above the inlet opening B4. The inlet opening admits the fuel to a space below the rotor 55, and the peripheral ange of said rotor is provided with a port 66 which registers successively with the several discharge ports 85 to permit discharge of said fuel. The rotor is driven lby suitable gearing 61 connecting the gear I8 with the engine shaft II.

Each discharge port 65 of the distributor head 52. communicates, through a suitable connection 68, with a fuel line 69 leading to one of the engine cylinders. All such fuel lines 69 are led through an open passage 10 which connects the interior of the distributor housing 5I with the blower discharge branch I1 and the air induction manifold I4, and thence are carried inside said manifold, as indicated in Figs. ll and 2, to the respective, cylinders connected therewith. In Fig. 3,

only four fuel lines 69 are shown, to avoid confusion, but it is to be understood that there will beas many such fuel lines as there are cylinders supplied by that particular distributor. In Figs. 1 and 2, eight fuel lines are shown within the air manifold I6. They may be mounted in 4the manifold in any suitable manner. i

At each branch I5 of the manifold I4, one fuel line 69 is led off into said branch, and terminates in a socket 1I formed in the wall of said branch adjacent the cylinder inlet port I 6. An injection nozzle 12, of4 any suitable type, is mounted in the socket 1I, and serves to spray the fuel into the air stream as said air passes into the cylinder inlet port.

It will be seen from .the foregoing and by reference to Fig. 8 that the fuel distributor and the fuel distribution lines leading to the various cylinders are 'housed within the air induction system. 'I'he interior of the distributor housing 5I is open to the air manifold through the passage 10. Any

v fuel which may leak from a broken or defective fuel line will be drawn into the engine through the air manifold.' Any fuel that may leak from .the distributorvcan be drained off from the bottom of the housing .5I in any suitable manner, as for example by a small aperture 13, Fig. 3, leading into the air intake chamber 28, from which it will be drawn into the engine. The only exposed lfuel pipes are the inlet pipe 24 leading from the pump or other source of supply of the compensator 23, and the short pipe 26 leading from said compensator to the distributor. The danger from fire in the event of a broken or leaky fuel line is therefore reduced to a. minimum. Moreover,

housing the fuel distribution lines within the air manifold subjects the fuel to the temperature of the air within said manifold, which is valways above atmospheric temperature because of its super-atmospheric pressure, and thereby improvesvaporlzation of said fuel. In order to insure equal distribution of fuel to all cylinders,

the shorter fuel distribution llines' are made I slightly smaller in ,diameter than the longer lines.

been omitted from the drawings.

By properly proportioning the diameter of said lines to their length, the friction in all can be made equal.

An ignition distributor 14, Fig. 3, is mounted in the upper portion of the housing 5I above the fuel distributor, and is driven by the shaft 56.

channel 11 formed in the crank case at the rear being shown in Fig. 3, the shield conduit 19 is connected with the cover plate 18 by a bushing 80 which is pressure tight, as well as providing an electrical ground for said shield.

As a result of this construction, the ignition distributor 14 and the high-tension conductors 15 are subjected to the super-atmospheric pressure of the air induction system. Suitable apertures 8I are provided between the base of the ignition distributor 14 and the housing flange 82 on which it rests, so that the pressure within the fuel distributor housing passes into the ignition .distributor housing, and thence through the passage 16 into the channel 11. The ignition distributor housing is provided with a tight cover 2' 83. The pressure tight bushings 88 permit the super-atmospheric pressure to the channel 11 to pass into the flexible shield conduits 19 of the conductors 15, so that said conductors are maintained under super-atmospheric pressure throughout their length. Corona losses, which would otherwise occur through the'insulation and from the various conducting elements of the ignition distributorat the reduced air pressure encountered at high "altitudes, are thereby prevented. In as much as the fuel is not mixed with the air until just before it enters the cylinder, there is no danger of ignition of said fuel by accidental electrical discharge from those portions of the electrical system that are housed within the air induction system.

I claim:

1. In an internal combustion engine having a cylinder, means for supplying air to said cylinder under super-atmospheric pressure, means for supplying fuel to said cylinder, an-electric ignition system including a distributor for the ignition current, and an air tight housing inclosing said distributor, the interior of said housing being exposed to the pressure of said air supply.

2. In an internal combustion engine having a cylinder, an air induction system therefor operating at super-atmospheric pressure, means for supplying fuel to said cylinder, and an electric ignition system having a portion thereof housed within said air induction system.

3. In an internal combustion engine having a cylinder, an air induction system therefor operating at super-atmospheric pressure, a fuel sup-l ply system, and an electric ignition system, portions of said fuel and ignition systems being inclosed within said air induction system and exposed to the super-atmospheric pressure thereof.

4. In an internal combustion engine having a cylinder, an air induction system therefor. operating at super-atmospheric pressure, a fuel supply system including a timing and distributing valve, an electric ignition system including a distributor for the ignition current, a housing enclosing said fuel distributing valve and said ignition distributor, and means for conducting the super-atmospheric pressure of said airinduction system to the interior of said housing.

5, In an internal combustion engine having a plurality of cylinders, means for supplying air under super-atmospheric pressure, a manifold for conducting said air to said cylinders, means for supplying fuel, means for automatically maintaining a predetermined fuel to air ratio, a fuel distributing valve, and conduits for conducting the fuel from said distributing valve to the respective cylinders. said conduits being positioned wholly withinl said manifold and discharging said fuel into the supplied air adjacent the cylinder intakes.

6. In an internal combustion engine having a. cylinder, an air induction conduit for supplying air to the intake of said cylinder, means in said conduit driven by the engine for raising the pressure of the air flowing therethrough above atmospheric pressure, means for supplying fuel, a mov` able valve operated by the engine for timing the supply of fuel to the cylinder, an air-tight housing inclosing said fuel timing valve, a branch conduit connecting said air induction conduit with said housing, and a fuel distribution pipe leading from said timing valve through said branch conduit and said air induction conduit, said pipe terminating at a fuel discharge orifice positioned within said air induction conduit adjacent to the cylinder intake.

7. In an internal combustion engine having a cylinder, an air induction conduit for supplying air to the intake of said cylinder, means in said conduit driven by the engine for raising the pressure of the air flowing therethrough above atmospheric pressure, means for supplying fuel, a movable valve operated by the engine for timing the supply of fuel to the cylinder, an air-tight housing inclosing said fuel timing valve, a branch conduit connecting said air induction conduit with said housing, a fuel distribution pipe leading from said timing valve through said branch conduit and said air induction conduit, said pipe terminating at a fuel discharge orifice positioned within said air induction conduit adjacent to the cylinder intake, and a drain conduit connecting said housing with said air induction conduit.

8. In an internal combustion engine having a cylinder, an air induction conduit for supplying air to the intake of said cylinder, means in said conduit driven by the engine for raising the pressure of the air flowing therethrough above atmospheric pressure, means for supplying fuel, a shaft rotated by the engine, a fuel timing valve and an electric ignition timer positioned in adjacent relation and driven by said shaft, an airtight housing inclosing said fuel timing valve and said ignition timer, a branch conduit connecting said air induction conduit with said housing to raise the pressure therein, a fuel distribution pipe leading fromsaid timing valve through said branch conduit and said air induction conduit to a discharge orifice adjacent the cylinder intake, an electric conductor leading from said ignition timer to the cylinder, and an air-tight conduit surrounding said conductor, the last mentioned conduit opening into said housing and receiving pressure therefrom.

9. In an internal combustion engine having a cylinder, an air induction system having a pressure tight conduit for supplmng air under superatmospheric pressure to the intake of said cylinder, means for supplying fuel under super-atmospheric pressure, fuel metering means for maintaining a predetermined fuel to air ratio, said metering means being outside said air induction system and being controlled by the pressure differentials between the air in said induction system, the fuel, and the atmosphere, a movable valve operated by the engine-for receiving the fuel from said metering means and timing the supply thereof to the cylinder, said valve being Apositioned Within a portion of said air induction conduit, and a fuel pipe leading from said valve, through said conduit, said pipe terminating at a discharge orice within said conduit adjacent to the cylinder intake.

NATHAN C. PRICE.

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