US2841131A - Fuel metering system - Google Patents

Description

July 1, 1958 A. J. zuPANclc 2,841,131

FUEL METERING SYSTEM Filed Feb. 21, 1957 2 Sheets-Sheet l ATTORNEY July 1, 1958 A. J. ZUPANCIC 2,841,131

FUEL METERING SYSTEM Filed Feb. 21, 1957 2 Sheets-Sheet 2 IN V EN TOR. d e'zf'fzaazzczi: BY

ATTORNEY United States Patent FUEL METERING SYSTEM 'Albert J. Zupancic, Royal Oak, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application February 21, 1957, Serial No. 641,629

Claims. (Cl. 123-119) The present invention relates to an improved continuous flow type fuel metering system which is particularly adapted for use with a fuel induction system for an internal combustion engine.

The present system provides for the synchronized flow of fuel flow to all cylinders of the engine in sucha way as to insure an equalization of the power produced by each cylinder. Heretofore it has been the practice in most continuous flow fuel systems of the type to which the present invention relates to provide a single fuel metering valve for controlling the total quantity of fuel to be distributed to the individual cylinders. To thus meter fuel with a single valve requires relatively large ports or passages which inherently are less accurately controlled than small ports or passages. The present invention is directed to providing a unique metering system in which individual metering valves or their equivalents are utilized in supplying fuel to the individual cylinders. In this way more accurate control of fuel fiow is realized with a resultant economy in fuel consumption as Well as better engine response to operator demand.

The present fuel metering system also includes a unique device whereby the flow of fuel through the system is cut off under decelerating conditions resulting in the reduction of the amount of unburned hydrocarbons which are ungainfully exhausted from the engine. The present inventionalso includes adevice adapted to operate ,in conjunction with the deceleration fuel cut-01f device for at least periodically reestablishing the flow of fuel during condi-,

tions of incipient stalling While the engine is being decelerated, and which device also permits the engine m idle properly with the throttle valve closed.

Other improvements and advantages have resulted from the present invention as will be seen from a perusal of the detailed description which follows.

In the drawings: y

Figure l is a diagrammatic representation of the fuel system embodying thesubject invention;

Figure 2 is an isometric View of the fuel control valve; and

Figure 3 is a modification of the deceleration fuel cutoff system.

While the present fuel metering system has considerable general applicabilityv it is particularly adapted for use with a fuel induction system of the type which has-been shown diagrammatically in Figure 1. In Figure l the fuel metering device is shown generally at A, an air induc-' tion passage at B and a fuel supply pump at C. I

The metering device A includes a metering valve indicated generally at 10 and a servo'device 12 adapted to actuate the valve in response to certain engineoperating conditions as will now be more particularly described. The servo device 12 includes a pair of easing members 14 and 16 having a diaphragm member 18 peripherally clamped therebetween. has a spring supporting cavity 20 which houses one end of spring 22 the other end of which coacts with the diaphragm 18 and urges the latter in a downwardly direction.

The upper casing member 14 2,841,131 Patented July 1, 1958 A disc or washer-like member 24 is slidably disposed in casing portion 20 to provide an adjustable seat for spring 22. Disc 24 may be axially adjusted by a screw 26 to vary the rate of the spring 22 and thus vary the operation of the diaphragm 18.

A boss 28 is also formed in theupper casing member 14 and within which boss at fitting 30 is threadably mounted. Fitting 30 is adapted to connect with a passage 32 the other end of which communicates with a venturi portion 34 of the induction passage B anteriorly of throttle 35. A vacuum signal or force is created in passage 32 which is directly proportional to the mass of air flowing through the induction passage. This variable vacuum force is communicated to the chamber 36 defined by the diaphragm 18 and the upper casing member 14 and works in opposition to the spring 22 in controlling the movement of the diaphragm. As the mass of air flowing through induction passage B increases the vacuum transmitted to chamber 36 will similarly increase moving the diaphragm upwardly against the force of spring 22.

The diaphragm 18 has a rod 38 centrally fixed thereto which is adapted to move up and down with the movement of the diaphragm. A lever 40 is articulated intermediate its ends to the rod 38 and has one end 42 which is pivotally connected to the fuel metering valve 10. The other end 44 of lever 40 is appropriately articulated to a rod 46 to provide an adjustable fulcrum for the lever system 38-40.

The metering valve 10 shown in Figures 1 and 2 includes a plurality of stepped or tapered portions 50. Valve 10 is slidably mounted within a casing 52. A flat spring element 54 is disposed between the casing 52 and the sliding bar valve member 10 to retain the latter in position within the casing. As better shown in Figure 2, casing. 52 has a plurality of longitudinally spaced ports 56 formed therein. An equal number of axially aligned ports 58 are disposed on opposite sides of the casing. The sliding valve member 10 is adapted to slidably move between the oppositely disposed sets of ports 56 and 58 such that each tapered valve portion controls the flow of fuel to an oppositely disposed pair of ports 56 and 58. Casing 52 has a boss 60 formed therein which is adapted to have one end of a passage 62 connected thereto, the other end of the passage connecting with the fuel pump C which continuously supplies fuel under pressure to the casing 52. Each of the ports 56 and 58 has a fuel line 64 connected thereto and each of which lines 64 is adapted to supply fuel for one cylinder of the engine.

An additional casing 68 is provided as a part of the fuel metering device A and is contiguously disposed with respect to casing 52 having a wall 70 in common therewith. Casings 52 and 68 are in communication through an opening 72 in wall 70. An outlet 74 is formed in the bottom of casing 68 and communicates with any suitable passage means 76 leading back to a fuel supply tank. The

- opening 72 is positioned that regardless of the position of the sliding bar valve 10 communication will at all times be established between the casings 52 and 68 providing a continuous flow of fuel through the fuel casing 52 to insure the fuel lines are at all times filled with fuel. Without providing for the continuous flow of fuel through the fuel metering system there would be a problem of air or vapor getting into the fuel lines resulting in an uneven flow of fuel in a line so affected.

In the species of fuel control valve shown in Figures 1 and 2 each tapered or wedged shaped surface 50 of the valve 10 is'adapted to coact with a pair of axially aligned ports to control the fuel flow thereto as determined by the valves position within the casing 52, as described in the copending application Serial No. 633,349 filed January 9, 1957. The position of valve 10 is determined by the diaphragm member 18 which, as already noted, is positioned in accordance with the mass of air flowing through induction passage B.

A pair of conduits 80 and 81 are connected in parallel with the passage 32 in order to insure an adequate diaphragm controlled force under idling or low engine speed conditions. Conduit 80 communicates at one end with the air induction passage immediately anterior of the throttle 35 and at its other end with passage 32. Conduit 81 communicates at one end With the induction passage immediately posterior to the throttle 35 and likewise at its other end with passage 32. When the throttle is closed no air will be flowing through the induction passage, therefore, there will be no vacuum from venturi 34 in passage 32. Under this condition manifold vacuum in the induction passage posteriorly of the throttle 35 will be transmitted through conduit 81 to passage 32 and hence to chamber 36 whereby the diaphragm will be moved upwardly against the force of spring 22 to an extent which will cause the slide valve to at least partially uncover the ports 56 and 58 leading to the conduits 64- feeding fuel to the individual cylinders, as described in Serial No. 633,349. In order to prevent atmospheric air from being bled into passage 32 and hence destroying the idle vacuum signal in conduits 81 and 32, a restrictor or orifice 82 is formed in passage 32 which permits the maintenance of a sufiicient vacuum force in the metering chamber 36 to insure the requisite flow of fuel for idling. An adjusting screw 84 is provided in conduit 81 to permit adjustment of the quantity of idling fuel.

Conduit 80 provides an elf-idle vacuum control force under conditions when the throttle is slightly opened and at which time the quantity of air flowing through the induction passage is still too small to provide an adequate control force in chamber 36. Under this condition the air flowing around throttle will create a vacuum in conduit which insures an adequate vacuum control force in chamber 36 until such time as the air begins to flow in greater quantity through the venturi 34 to develop a suitable vacuum signal. An adjusting screw 85 is likewise provided in conduit 80 for adjusting the fuel flow under off-idle conditions.

An idle air passage 86 also communicates with the induction passage posteriorly of the throttle valve 35 and includes an adjusting screw 87 whereby the idle air flowing into the induction passage may be controlled thereby controlling the idling speed of the engine.

While the system as thus far described is sufficient to provide adequate fuel to the engine during idling and normal road load conditions, it is necessary to provide a full load enrichment device, indicated generally at 90, which will provide for additional fuel under high load or power conditions. Device 90 includes a servo mechanism comprising upper and lower casing members 92 and 94 having a diaphragm 96 peripherally clampedtherebetween and which diaphragm is urged downwardly by a spring member 98 disposed between the diaphragm 96 and the upper casing member 92. The lower casing is suitably apertured to slidably mount the rod 46 therein which is centrally fixed to the diaphragm 96. As already noted rod 46 has one end of lever 40 articulated thereto. The upper casing 92 through a suitable connection 100 connects with any suitable passage communicating with the engine intake manifold whereby the chamber 102 defined by the upper casing 92 and the diaphragm 96 has manifold vacuum communicated thereto. Manifold vacuum acts on the diaphragm 96 in opposition to the force of spring 98 to determine the position of rod 46. Under normal operating conditions the manifold vacuum in chamber 102 will be of a sufficiently high value to move the diaphragm to its upper position, shown in Figure 1, to provide a road load .position for the fulcrum end 44 of .lever 40.

When the operator depresses the accelerator pedal, efiecting an increased .power demand, manifold vacuum will decrease permitting the spring 98 to shift the rod 46 downwardly to its full load enrichment position and in so doing shift the sliding valve 10 upwardly to completely uncover the fuel ports 56 and 58 to provide the maximum amount of fuel to the cylinders. As soon as the maximum power situation has been satisfied manifold vacuum will again increase shifting the rod 46 once again to its upper or road load position for more economical operation. The upper casing member 92 has an adjustment screw 104. mounted therein for adjustably determining the road'load position of the rod 46 which abuts thereagainst in its upward travel. Similarly an adjustment screw 106 is provided in casing 94 against which the lower end of rod 46 is adapted to abut to determine the full load position of the rod. It is apparent that the adjustment screws 104 and 106 may be regulated in accordance with the type of engine operation desired. When the rod 46 is shifted either under the influence of spring 98 or manifold vacuum the point of connection of rod 40 and lever 38 momentarily becomes the fulcrum point of the lever 40.

There are occasions in the operation of the engine when it is desirable to completely out off the supply of fuel to the fuel lines 64. Such an occasion arises when the vehicle is decelerating under which condition fuel normally continues to be supplied to the engine cylinders and at least part of said fuel is pumped therefrom in an unburned state. As is well known such a condition is both wasteful of fuel and contributes to the contamination of the air.

To insure the cutting off of fuel to the engines cylinders when the engine is decelerating a valve mechanism indicated generally at 110 is provided. Mechanism 110 includes a valve body 112 within which is slidably disposed a spindle type valve 114 having axially spaced lands 116 and 118. A passage 32' leads from valve body 112 to the diaphragm casing 14 and is in communication at all times with the space between lands 116 and 118. An atmospheric vent passage communicates with the valve body 112 as does the vacuum passage 32. With the valve in the position shown in Figure 1 land 116 blocks communication between vacuum passage 32 and passage 32' while land 118 permits atmospheric passage 120 to bleed atmospheric pressure to chamber 36 causing spring 22 to shift the diaphragm 18 and metering valve 10 to a position completely closing the fuel metering ports 5658. Spindle valve 114 is in the position shown in Figure 1 only under engine decelerating conditions as will now be described. Valve 114 is axially shifted by a solenoid 122 which when energized, as shown in Figure 1, moves the valve to the right against the force of a return spring 124. Solenoid 122 is adapted to be energized by a switch 126 suitably mounted on the induction passage casing. A lever 128 is connected with the throttle valve 35 in such a way that when the throttle is closed lever 128 closes the contacts of switch 126 which conditions the circuit for energization of the solenoid 122. However, in order for current to be supplied to the solenoid from the generator 130 the generator voltage output must be sufliciently high .to close a relay 132. The generator voltage will always be of a sufiiciently high value during normal engine operating as well as decelerating conditions to close the relay 132 and thus will always energize the solenoidlZZ when the throttle is closed. To insure pr per idling of the engine it is necessary that the spindle valve 114 be shifted to its normal running position in which land 116 uncovers vacuum passage 32 permitting vacuum to act on diaphragm 18 for idling purposes as already described. Accordingly, relay 132 is so adjusted that the generator output under idling conditions is insufficient to maintain the relay in a closed position and 1hence, -notwithstanding that throttle valve 35 has closed the switch '126, current cannot flow :to the solenoid 122. Therefore, spring 124 will move the solenoid armature 134 to the left causing land 116 to uncover passage 32 and at the same time causing land 118 to block the atmospheric passage 120. In this way a control mechanism is provided whereby fuel is prevented from flowing to the cylinders when the engine is decelerating but which mechanism permits metered fuel to flow to the cylinders under idling conditions.

For the sake of convenience, relay 132 may be incorporated as a part of the voltage regulator by adding an additional set 'of relay points thereto and connecting switch 126 to one terminal thereof.

In lieu of the electrical deceleration fuel cut-ofi system shown in Figure 1 it is possible to utilize a mechanical system in which manifold vacuum controls a valve 140. In this case valve 140 is controlled by a servo 142 which includes a diaphragm 144 to which the valve stem 146 is centrally secured. A spring 148 within servo 142 normally biases diaphragm 144 to the right, as viewed in Figure 3, in which valve 140 communicates passages 32 and 32'.

A casing 149 is suitably mounted on the induction passage casing and communicates with the passage posteriorly of'throttle 35 through a conduit 150. A valve element 152 is disposed within casing 149 and projects through conduit 150in a manner permittingan enlarged head portion 154 to block flow through the conduit. A spring 156 normally biases valve 152 to a position closing conduit 150. The other end 158 of valve 152 projects within the induction passage and is adapted to be engaged by an arm 160 fixed to throttle 35. When throttle 35 is closed arm 160 moves valve 152 to the open position admitting manifold vacuum to casing 149.

Another conduit 162 connects casing 149 with servo 142 admitting manifold vacuum thereto when valve 152 is open. Thus with the throttle closed and the engine decelerating the high manifold vacuum posterior to throttle 35 will enter servo 142 and overcome spring 148 causing valve 140 to block passage 32 and open passage 120 so as to bleed atmospheric pressure into metering chamber 36 causing fuel flow to be completely out ofi as already described.

Since manifold vacuum under idling conditions is less than when the engine is decelerating spring 148 is cali brated to overcome idling manifold vacuum in servo 142 and shift valve 140 to the position shown in Figure 3 which permits the idling force to again control metering diaphragm 18.

The various embodiments of the invention as shown and described are illustrative and various structural modifications may be made within the scope of the invention as hereinafter set forth in the appended claims.

I claim:

1. A fuel metering system for an internal combustion engine comprising an induction passage for delivering airto the cylinders of said engine, a throttle valve for controlling the quantity of air flowing through said passage, a source of fuel under pressure, a plurality of fuel conduits each of which is adapted to deliver fuel to one cylinder of said engine, valve means for metering the quantity of fuel delivered to said fuel conduits, first servo means connected to said metering valve, a venturi in the induction passage, a first conduit adapted to communicate the venturi with said servo means whereby said servo and metering valve are responsive to the mass of air flowing through the system, a second conduit adapted to communicate atmospheric pressure to the servo means, a valve device for controlling flow through said conduits, a second servo for controlling said valve device, and throttle controlling means for actuating said second servo means whereby with the throttle at least partially open said valve device will communicate the first conduit with said first servo means while with the throttle closed and the engine decelerating said valve device will communicate 6 the second conduit with the first servo means thereby cutting ofi the flow of fuel to the cylinders.

2. A fuel metering system for an internal combustion engine comprising an induction passage for delivering air to the cylinders of said engine, a throttle valve for controlling the quantity of air flowing through said passage, a source of fuel under pressure, a plurality of fuel conduits each of which is adapted to deliver fuel to one cylinder of said engine, valve means for metering the quantity of fuel delivered to said fuel conduits, first servo means connected to said metering valve, a venturi in the induction passage, a first conduit adapted to communicate the venturi with said servo means whereby said servo and metering valve are responsive to the mass of air flowing through the system, a second conduit adapted to communicate atmospheric pressure to the servo means, a valve device for controlling flow through said conduits, a second servo for controlling said valve device, throttle controlling means for actuating said second servo means whereby with the throttle at least partially open said valve device will communicate the first conduit with said first servo means while the throttle closed and the engine decelerating said valve device will communicate the second conduit with the first servo means thereby cutting off the flow of fuel to the cylinders, and means responsive to engine speed for modifying the actuation of said second servo means by the throttle controlling means.

3. A fuel metering system as defined in claim 2 in which the engine speed responsive means causes the second servo means to communicate the first conduit with the first servo whenever the engine is idling.

4. A fuel metering system for an internal combustion engine comprising an induction passage for delivering air to the cylinders of said engine, a throttle valve for controlling the quantity of air flowing through said passage, a source of fuel under pressure, a plurality of fuel conduits each of which is adapted to deliver fuel to one cylinder of said engine, valve means for metering the quantity of fuel delivered to said fuel conduits, first servo means connected to said metering valve, a venturi in the induction passage, a first conduit adapted to communicate the venturi with said servo means whereby said servo and metering valve are responsive to a vacuum force which is proportional to the mass of air flowing through the system, a second conduit adapted to communicate atmospheric pressure to the servo means, a valve device for controlling flow through said conduits, a second servo for controlling said valve device, throttle controlling means for actuating said second servo means whereby with the throttle at least partially open said valve device will communicate the first conduit with said first servo means while with the throttle closed and the engine decelerating said valve device will communicate the second conduit with the first servo means thereby cutting off the flow of fuel to the cylinders, and third conduit means communicating the induction passage proximate the throttle valve with the first servo means whereby manifold vacuum will be delivered tosaid latter servo means when the venturi vacuum force is insufficient to control the first servo means.

5. A fuel metering system as defined in claim 4 in which the third conduit means comprises a pair of passages connected in parallel relation with the first conduit, one of said pair of passages communicating with the induction passage immediately anterior of the throttle valve and the other of said passages similarly communicating immediately posterior of the throttle valve.

6. A fuel metering system for an internal combustion engine comprising an induction passage for delivering air to the cylinders of said engine, a throttle valve for controlling the quantity of air flowing through said passage, a source of fuel under pressure, a .plurality of fuel conduits each of which is adapted to deliver fuel to one cylinder of said engine, valve means for metering the quantity of fuel delivered to said fuel conduits, first servo means con- I nected to said metering valve, a venturi in the induction passage, a first conduit adapted to communicate the venturi with said servo means whereby said servo and metering valve are responsive to the mass of air flowing through thesystem, a second conduit adapted to communicate atmospheric pressure to the servo means, a valve device for controlling flow through said conduits, a solenoid for controlling said valve device, means normally biasing said valve device in a position communicating said first conduit with the first servo means, a switch for actuating said solenoid, said throttle being adapted when closed to close said switch to energize the solenoid causing the valve device to communicate the second conduit with the first servo'means whereby the metering valve cuts off the flow of fuel to the cylinders, and engine speed responsive means for deenergizing said solenoid when the engine reaches idling speed.

7. A fuel metering system as defined in claim 6 in which said engine speed responsive means comprises an engine driven generator and a relay serially connected with said switch and said solenoid circuit, said relay being adapted to open said circuit when the engine reaches idling speed.

8. A fuel metering system for an internal combustion engine comprising an induction passage for delivering air to the cylinders of said engine, a throttle valve for controlling the quantity of air flowing through said passage, a source of fuel under pressure, a plurality of fuel conduits each of which is adapted to deliver fuel to one cylinder of said engine, valve means for metering the quantity of fuel delivered to said fuel conduits, first servo means connected to said metering valve, a venturi in the induction passage, a first conduit communicating the venturi with said servo means whereby said servo and metering valve are responsive to the mass of air flowing through the system, a second conduit adapted to communicate atmospheric pressure to the servo means, a first valve device for controlling flow through said conduits, means normally biasing said valve to a position communicating the first conduit with said first servo means, a second servo for controlling said valve device, a second valve device disposed in the induction passage posterior to the throttle valve, a third conduit connecting said second valve device with the second servo, and an element operable by the throttle valve when closed to open the second valve device to permit manifold vacuum to actuate the second servo means and thereby communicate the second conduit with the first servo means to cut off the flow of fuel to the cylinders.

9. A fuel metering system as defined in claim 8 in which the valve biasing means is calibrated to exceed the force of manifold vacuum acting on the second servo means under engine idling conditions whereas under engine decelerating conditions the manifold vacuum force exceeds that of the valve biasing means.

10. A fuel metering system as defined in claim 8 in which the second valve device includes spring means normally closing said device and thereby precluding manifold vacuum from entering said third conduit.

No references cited.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,841,131 July .1, 1958 Albert J Zupanoic It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, line 47, after "idling" insert be vacuum Signed and sealed this 7th day of October 1958.

SEAL) ttest:

KARL H-o .AXLINE Attesting Oflicer ROBERT C. WATSON Commissioner of Patent;

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