US2877002A - Fuel injection system - Google Patents

Description

March 10, 1959 ...1. .lsoLzA Erm.

Filed Apr-11 a. 1 957 @wam/2M@ United States Patent FUEL INJECTION SYSTEM Application April 8, 1957, Serial No. 651,326 4 Claims. (Cl. 261-23) The present invention relates to a fuel metering system of the fuel injection type.

The present fuel system is basically of the mass air ow type in which the quantity of fuel supplied to the individual cylinders of the engine is proportional to the mass of air flowing through the system. In the previous systems from which the present invention is descended, a linkage system has been provided which connects a control diaphragm to a fuel metering valve to control the position of the valve in accordance with the magnitude of a vacuum signal acting on the diaphragm. It has been necessary heretofore to provide means acting in conjunction with such linkage whereby an enrichment of the fuel air mixture was possible under conditions of high power demand while insuring a more economical fuel llow under normal operating conditions. In these previous type systems the fuel enrichment for high demand operation was achieved by changing the mechanical advantage of the linkage system. The problems with this type of system are the inherent inertia of the linkage parts delaying the response to operator demand, the need for accurate balancing of parts and the general susceptibility to malfunctioning.

In the present device a fixed ratio linkage mechanism is employed and variations inthe fuel-air mixture obtained solely by controlling the magnitude of the metering vacuum signal acting on the diaphragm. In general, this is obtained by selecting a linkage ratio which will provide an air fuel ratio which is slightly richer than that required for full throttle operation and thereafter providing bleed means for reducing the metering vacuum to the level required for full throttle operation. In addition, however, additional bleed means responsive to engine load is provided for bleeding down the metering vacuum signal still further to the mixture required for maximum economy. In this way the fuel `control linkage is greatly simplified, made more responsive to operator demand, and the metering system in general made more reliable.

The drawing represents a diagrammatic representation of a fuel injection system embodying the subject invention.

The fuel injection system includes an air intake casing having a passage 12 including a portion cooperating with a plug 16 to define an annular venturi passage 18. A throttle valve 20 is mounted in the intake passage 12 posteriorly of the venturi 18.

An additional casing 22 is attached to intake casing 10 and forms a part of the intake passage 12. In order to provide an enriched fuel-air mixture forl cold starting and cold running operation it has been found desirable to provide an air or chokevalve 24 in casing 22. Valve 24 is adapted to reduce the quantity of air supplied to the engine when the engine temperatures are lowv as de.- termined by a suitable automatic control mechanism, not shown. The cold enrichmentdevice is described in detail in copending application Serial No. 658,091, led May 9, 1957, in the nameof Dolza and Kolbe. An air ICC 2 cleaner 26 is adapted to be mounted on casing 22 in order to filter the air being inducted into the system.v

The air from induction passage 12 communicates with a manifold or plenum chamber, not shown, from whence it flows to individual cylinder intake passages 30. The cylinder intake passages 30` each have 'a nozzle 32 dis-v; posed therein which through a conduit 34 delivers fuel to the cylinder from a metering mechanism indicated generally at 36. Thus the fuel and air are mixed just prior to entry into the cylinder.

The metering device 36 includes a casing 38 and a cover 40 between which there is peripherally clamped av flexible diaphragm 42. Diaphragm y 42 is connected through a linkage mechanism 44 to a metering valve 46 whereby the movement of the diaphragm will in turn impart a movement to the valve to meter the quantity of -fuel flowing to the individual cylinder nozzles. Casing 38 includes a bore 50 within which is disposed a fixed sleeve 52 having a bore 54 slidably receiving a valve member 56. The lower end of bore 50 is communicated through a port 58 and a conduit 60 with a source of fuel under pressure indicated generally at 62. The sleeveA 52 includes a plurality of radially disposed passages 64` communicating at their inner ends with bore 54 and at their outer ends with an annular passage 66 formed in the sleeve.

The slidable valve member 56 'has a longitudinal .pas-A sage 68 formed therein and which is in open communication at its lower end with the bore 50 and at its upper^ end communicates with a radially relieved portion 70 of the valve through radial ports 72. Thus, with the valve in the position shown fuel under pressure will be supplied to the lower end of bore 50 from which .it will flow through passage 68, radial ports 72 to annular chamber 70 and to the radial passages 64. Casing 38 has formed therein outlet passages 76, corresponding in number to the cylinders of the engine, which communicate with the annular passage 66 in sleeve 52. A fitting 78 is adapted to be threaded within the casing to connect the` fuel conduits 34 with the metered fuel outlet passages 76.

In order to maintain a continuous ow of fuel through the metering system, the fuel source 62 provides a quantity of fuel which is normally in excess of the requirements of the engine. The slidable valve member 56 is adapted, in accordance with conditions to be subsequently conv sidered, to meter the requisite quantity of fuel to the fuel nozzles with the excess fuel being bypassed and returned to the fuel source. To this end, sleeve 52 has additional radial passages formed therein which similarly communicate at their inner end with bore 54 and at their outer ends with an annular passage 82. The annular passage 82 communicates with the fuel source 62 through a passage 84 and a fuel return conduit 86. The end 88 of the slidable valve member 56 coacts with radial passages 80 to vary the opening thereof and thus the quantity of fuel bypassed through conduit 86 back to fuel source 62. In this way the quantity of fuel delivered to the radial fuel outletl passages 64 is determined by the amount of fuel bypassed through radial spill passages 80. Under maximum power requirements the valve member 56 will, as shown in the drawing, block the bypass or spill passages 80 permitting the full flow of fuel from the fuel source 62 to be delivered to the radial fuel outlet passages 64 and the fuel nozzles 32. The function of the fuel system as thus far described is essentially the same as set forth indetail in copending application Serial l No. 608,853, Dolza, led September 10, 1956. I

The slidable valve member 5.6 has a link 90 articulatedthereto andthe other end of which link is similarly connected to a lever 92 tixedly pvoted at 94 to a supportingf bracket 96 mounted within casing' 38. .The end of lever 9 2 remote Yfrom the `:metering.valve .46. basa. controlrod;

3 9'8 articulated thereto and the other end of whichcontrol rod is c/e'ntrllylired toth'vnitering diaphragm 42. The control rod 98 projects through a seat 100 formed in the upper wall 102 of casing 3 8 and isY fixed to the. diaphragm through a mountingplug 104..

With the slidable plunger 56 in the position shown, the engine is inthe process of being started. The signal modifier blade 24 effects a depression between itself and throttle blade 20. This depression is imposed upon diaphragm 42 through conduit 108 and via associated linkages, positioning thevalve 56 as shown. A pump 161 supplies low pressure make-up fuel from the gasoline tank to fuel source 62 through a conduit 162. The supply p ump 161 also pumps fuel through the fuel filter 163 in conduit. 16,4 into port 16S andv sleeve passage 166 where it enters metering valve annulus 70 to supplement the quantity of fuel supplied to the cylinders during cranking. As soon as the engine starts fuel pressure pushes the slidable valve 56 up to the operative metering position uncovering spill ports 80 and covering passage 165.

When the engine is stopped the hot fuel in the supply pump 161, filter 162, and associated lines and ports expands. If allowed to ow into the port 30, the engine will be flooded. Thus a means is incorporated to hold the slidable valve 56 in the uppermost position when the engine is inoperative. To this end, a threaded rod 101 is. mounted in a tapped opening in casing 38 and cover 40. A spring 103 is connected at one end to rod 101 and at theV other end to lever 92 to retain the metering valve member 56 in its uppermost position when the system is inoperative. It is also apparent that by adjusting the nut 105 on rod 101 the rate of actuation of the metering valve 46 may be varied, if desired.

A chamber 106 is formed by diaphragm 42 and cover 40 and is communicated with the venturi throat 18 by a conduit 108 whereby the chamber is maintained under a vacuum which is proportional to the mass of air flowing through the venturi. Thus, in general, as the mass of air flowing through the venturi increases so will the vacuum in chamber 106 increase to raise diaphragm 42, control rod 98 and to lower the metering valve member 56 thereby increasing the quantity of fuel supplied to nozzles 32. The chamber 110 delined by the diaphragm 42 and the upper wall 102 of casing member 38 is maintained at substantially atmospheric pressure through a branch conduit 112 which communicates with atmospheric conduit 114.

While the variations in vacuum in chamber 106 are sufcent to meter the fuel being supplied to nozzles 32 under normal operating conditions, it is necessary to provide means whereby a maximum amount offuel may be supplied to the nozzles under conditions of high engine load. Accordingly, a mechanism 118 is provided in which the vacuum force in chamber 106v may be bled or modulated to reect changes in engine load. Cover 40 is formed to provide an annular recess 120 which, in combination with a diaphragm l122 peripherally clamped between cover 40 and a recessed casing 124, defines a chamber 126. Chamber 126 communicates through a conduit 128 to atmospheric conduit 114. The cover 40 is further formed to provide passages 130 and 132 which connect vacuum chamber 106 with the atmospheric chamber 126. Flow through passages 130-132 is controlled by an adjustable needle valve member 134. As already noted, the linkage mechanism 44 is originally adjusted to provide a fuelair ratio slightly richer than that required for full power operation. By adjusting needle valve 134 atmospheric pressure may be bled into chamber 106 reducing the vacuum force therein to a value determining the full power fuel ow through the metering valve 46. Thus, by screwing in the atmospheric bleed valve 134 the metering signal in chamber 106 may be increased and, correspondingly, may be decreased by opening the atmospheric bleed.

`Cover 40 has an additional bleed passage 140 formed through-a boss 142 and which passage-is connected in asraooa 4 parallel with the maximum power fuel-air ratio adjustment passages and 132 to communicate vacuum chamber 106 with the atmspheric chamber 126. Cover 124 and diaphragm 122 define a chamber 146 which is communicated through a port 148 and a conduit 150 to the induction passage 12 posteriorly of the throttle valve 20. Diaphragm 122 has a valve member 152 centrally mounted thereon which is biased by a spring 154 to close bleed passage 140. Manifold vacuum is adapted to act upon the diaphragm 122 to move the latter and valve 152 upwardly against the force of spring 154. Under normal operating conditions manifold vacuum in conduit 150 s sutlicient to unseat valve 152 to connect the chamber 106 to the atmospheric chamber 126 thereby bleeding the metering vacuum signal down to-a level which positions the metering valve 46 for normal engine operation. However, in the event of a sudden demand for power, as by depressing the acceleration pedal, whichV is followed by a decrease in manifold vacuum in chamber 146, spring 154 will seat valve 152 blocking atmospheric bleed passage 140. Seating valve 152 in turn raises the vacuum force in chamber 106 and provides for the maximum delivery of fuel to the nozzles as already described. After the load on the engine is reduced manifold vacuum in a chamber 146 will again increase suciently to open atmospheric bleed passage 140 reducing the fuel-air ratio to its economy level.

Diaphragm control spring 15,4 seats upon a washer 156 which is axially adjustable within the chamber 146by a screw 158 which may adjust the rate of spring 154 to vary the operation of bleed control valve 152. Further, the adjusting screw 158 is mounted in an axially adjustable sleeve 160 rotatably mounted within casing 124 and which sleeve is Yadapted to regulate the amount of opening of valve 152 and thereby the maximum quantity of atmos pheric air bled through passage 140.

We claim:

l. A fuel injection system for an internal combustion engine comprising an intake passage for supplying air to the individual cylinders of the engine, venturi means formed in said passage, a throttle valve disposed in said passage posteriorly of the venturi, a source of fuel under. pressure, conduit means communicating said fuel source with the individual cylinders of said engine, a metering valve disposed in said conduit means for varying the quantity of fuel supplied to said cylinders, servo means operatively connected to said valve, rst conduit means communicating said servo with said venturi whereby a vacuum force is created in said servo which is proportional to the mass of air owing through the said venturi, second conduit means adapted to communicate atmos-. pheric pressure with said servo, a first valve providing a continuous atmospheric bleed into the servo to control the vacuum force acting on said servo, the atmospheric bleed of said lirst valve acting on the same side of said servo as said vacuum source, a second atmosphericbleed valve, a third conduit connecting the intake passage posteriorly of the throttle with the second valve whereby manifold vacuum may open said latter valve, and means biasing said second valve toward a closed position against the force of manifold vacuum.

2. A fuel injection system for an internal combustion engine comprising an intake passage for supplying air to the individual cylinders of the engine, venturi means formed in said passage, a throttle valve disposed in said passage posteriorly of the venturi, a source of fuel under pressure, conduit means communicating said fuel source with the individual cylinders of said engine, a metering valve `disposed in said conduit means for varying the quantity of fuel supplied to said cylinders, servo means operatively connected to said valve, first `conduit means communicating said servo with said venturi whereby a vacuum force is created in said servo `which is proportional to the mass of air tiowin-g through the said venturi,' second conduit means adapted to communicate atmos-` pheric pressure with said servo, a first valve providing a continuous atmospheric bleed into the servo to control the vacuum force acting on :,-raid servo, the atmospheric bleed of said rst valve acting on the same side of said servo as said vacuum source, a second atmospheric bleed valve, a servo device connected to the second valve, a third conduit connecting the intake passage posteriorly of the throttle with the second valve servo device whereby manifold Vacuum may open said latter valve, and means biasing said second valve toward a closed position against the force of manifold vacuum.

3. A fuel injection system for an internal combustion engine comprising an intake passage for supplying air to the individual cylinders of the engine, venturi means formed in said passage, a throttle valve disposed in said passage posteriorly of the venturi, a source of fuel under pressure, conduit means communicating said fuel source with the individual cylinders of said engine, a casing, a metering valve disposed in said casing and coacting with said conduit means for varying the quantity of fuel supplied to said cylinders, a cover for the casing, a diaphragm clamped between the cover and casing, linkage means operatively connecting said valve and diaphragm, conduit means communicating said diaphragm with said venturi whereby a vacuum force acts on the diaphragm which is proportional to the mass of air owing through the said Venturi, a pair of passages formed in said cover for permitting atmospheric pressure to act on the same side of said diaphragm, an adjustable needle valve controlling iiow through one of the atmospheric passages, a diaphragm actuated valve for controlling the flow through the other atmospheric passage, spring means biasing the diaphragm actuated valve in a closed position, and a conduit connecting the diaphragm actuated valve with the intake passage posteriorly of the throttle permitting manifold vacuum to open said valve.

4. A fuel injection system for an internal combustion engine comprising an intake passage for supplying air to the individual cylinders of the engine, venturi means formed in said passage, Va throttle Valve disposed in said passage posteriorly of the venturi, a source of fuel under pressure, conduit means communicating said fuel source with the individual cylinders of said engine, a casing, a metering valve disposed in said casing and coacting with said conduit means for varying the quantity of fuel supplied to said cylinders, a cover for the casing, a diaphragm clamped between the cover and casing, linkage means operatively connecting said valve and diaphragm, conduit means communicating said diaphragm with said venturi whereby a vacuum force acts on the diaphragm which is proportional to the mass of air owing through the said venturi, a pair of passages formed in said cover for permitting atmospheric pressure to act on the same side of said diaphragm, an adjustable needle valve controlling flow through one of the atmospheric passages, a `diaphragm actuated valve for controlling the ow through the other atmospheric passage, spring means biasing the diaphragm actuated valve in a closed position, a conduit connecting the diaphragm actuated valve with the intake passage posteriorly of the throttle permitting manifold vacuum to open said valve, means for adjusting the rate of the spring means, and an adjustable stop for said diaphragm actuated valve.

References Cited in the file of this patent UNITED STATES PATENTS 2,502,679 Stanly Apr. 4, 1950 2,541,316 Winkler Feb. 13, 1951 2,580,294 Griffon Dec. 25, 1951

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