US2727498A

US2727498A - Fuel supply apparatus for an internal combustion engine

Info

Publication number: US2727498A
Application number: US338646A
Authority: US
Inventors: Neville M Reiners
Original assignee: Cummins Engine Co Inc
Current assignee: Cummins Inc
Priority date: 1953-02-25
Filing date: 1953-02-25
Publication date: 1955-12-20
Anticipated expiration: 1972-12-20

Description

Dec, 269, 1955 N. M. REINERS FUEL SUPPLY APPARATUS FOR AN INTERNAL COMBUSTION ENGINE 6 Sheets-Sheet 1 Filed Feb. 25, 1953 Q1 j INVENTOR. Uil fifjzeimerg li e Dec. 20, W55 N. M. REHNERS 2,727,498

FUEL SUPPLY APPARATUS FOR AN INTERNAL COMBUSTION ENGINE IN V EN TOR.

Dam 7 AIM/ 1v Dec. 20, 1955 N. M. REINERS 2,727,498

FUEL SUPPLY APPARATUS F OR AN INTERNAL COMBUSTION ENGINE Filed Feb. 25, 1953 6 Sheets-Sheet 3 INVENTOR. A/eULZZe/Yfiewm BY EM ,4:

Dec. 20, 1955 N. M. REINERS FUEL SUPPLY APPARATUS FOR AN INTERNAL COMBUSTION ENGINE 6 Sheets-Sheet 4 Filed Feb. 25, 1953 A/ez/LZZe MW q J If Kw WW a a I QRN K 13 PL 1 NW 1% r @W Dec. 20, 1955 N. M. REINERS 2,727,498

FUEL. SUPPLY APPARATUS FOR AN INTERNAL COMBUSTION ENGINE Filed Feb. 25, 1953 6 Sheets-Sheet 5 162 F 'T 5 l 161 I 154' if 155 1 WP l J I i 130 y J J54 131% iflf/ [1 J53 133 J a J J45 J92 I1 144 .134 y 1414 a J35 J41 J36 J45 J J36 145 .743 Iii/m.

J43 J42 ez/illefffienem;

BY D ALAa W Dec. 20, 1955 N. M. REINERS FUEL SUPPLY APPARATUS FOR AN INTERNAL COMBUSTION ENGINE,

6 Sheets-Sheet 6 Filed Feb. 25, 1953 IIIVEN TOR. ZI/QULZZQMJZQL 11MB. ALVA? H dr United States Patent FUEL SUPPLY APPARATUS FOR AN INTERNAL COMBUSTION ENGINE Neville M. Reiners, Columbus,

Engine Company, of Indiana Ind., assignor to Cummins Inc., Columbus, Iud., a corporation The invention relates generally to fuel supply apparatus for internal combustion engines and more particularly to a fuel supply apparatus for a multi-cylinder engine of the diesel type.

The general object of the invention is to provide a novel fuel supply apparatus for delivering accurately metered quantities of fuel to the respective cylinders of the engine under varying load and speed conditions.

Another object is to provide a novel fuel supply apparatus of the foregoing character, in which the delivery of fuel to the cylinders is promptly responsive to adjusttnent of the manually operable throttle throughout the entire speed range of the engine.

More specifically, it is an object to provide a novel fuel supply apparatus in which any air entering the fuel supply passages of the apparatus from the cylinders is purged before the time in the cycle of operation when fuel is to be supplied to the cylinders so that adjustment of the manually operable throttle will become immediately etfective to vary the fuel supplied.

Still another object is to provide a novel fuel supply apparatus in which the metering of the fuel is dependent upon the pressure of the fuel and the fuel pressure is controlled in such a manner as to provide a predetermined torque curve for the engine throughout the speed range thereof.

A still further object is to provide a fuel supply apparatus in which flow of fuel in the various passages thereof occurs only for such time as is needed for purging the passage of air and for supplying the cylinders with fuel, thus reducing the demands on the pump.

A further object is to provide a novel fuel injector for an engine of the foregoing character.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings, in which:

Figure l is a side elevational view of a fuel supply unit constituting a portion of the apparatus embodying the features of the invention.

Figure 2 is an enlarged view, partially in section, of the left-hand end of the unit shown in Figure 1.

Figure 3 is a longitudinal vertical sectional view of the unit shown in Figure 1 and taken generally on the line 33 of Figure 2.

Figure 4 is a transverse vertical sectional view taken generally on the line 44 of Figure 3.

Figure 5 is a diagrammatic view of the complete apparatus, including parts of the supply unit shown in Figure l, as well as the injectors shown in Figures and 11.

Figures 6 to 9 inclusive are diagrammatic views showing different positions of the governor-operated valve constituting a portion of the supply unit shown in Figure 1.

Figures 10 and 11 are longitudinal sectional views of one of the injectors and showing the parts thereof in different positions.

Figures 12 and 13 are views similar to Figures 10 and 11 but showing a modified form of injector.

2,727,498 Patented Dec. 20, 1955 The fuel supply apparatus disclosed herein is similar in some respects to the apparatus disclosed in my copending application Ser. No. 265,698, filed January 9, 1952.

The present apparatus is adapted for delivering accurately metered quantities of fuel to the respective cylinders of a multi-cylinder engine of the diesel type under varying load and speed conditions. More particularly, the present apparatus is constructed so that the delivery of fuel to the engine cylinders is promptly responsive to adjustment of the manually operable throttle throughout the entire speed range of the engine. Engines of this character are utilized for many different driving requirements. In some instances, the engine is operated at a fairly constant speed and under fairly constant load conditions and the metering of fuel to the cylinders is easily controlled under such conditions. However, engines of this character are frequently utilized under widely varying conditions, that is, under wide variations of load and speed. One such instance is where the engine is used as the motive power for a vehicle. When so used, the engine may at one moment be subjected to a heavy load, as when the vehicle is climbing a hill, and then be relieved of such load with the engine operating at a high speed, as when the vehicle is going downhill with the engine in gear. Under such conditions, there is a tendency for air to accumulate in the passages supplying the fuel to the cylinders and, unless such air can be quickly purged from such passages, the engine will not respond promptly to the throttle when the latter is opened to meet increasing load conditions. The present apparatus is capable not only of providing accurately metered quantities of fuel to the respective cylinders of the engine but also is so constructed that the fuel supply will be promptly responsive to operation of the throttle so that the engine can meet rapidly changing load and speed conditions.

The apparatus shown herein is of the type in which a metering orifice of fixed size is provided for each cylinder with the orifices adapted to be opened and closed in a fixed timed relation to the engine cycle. Control of the flow of fuel through the meter'ng orifices is obtained by controlling the pressure of the fuel at the orifices, and the pressure is regulated in a manner to provide a predetermined torque curve for the engine. During certain portions of the engine cycle, air may be forced from the cylinders reversely through the metering orifices and into the fuel passages connected thereto. In the next cycle of operation, such air has to be purged before the proper amount of fuel will flow through the metering orifices. If the engine were operating under load at a speed above idling speed, the flow of fuel would normally be sufficient to prevent any accumulation of air. However, should the engine operate under a no-load condition but at speeds above idling, there is a tendency for the air to accumulate in the fuel passages. If the throttle is then opened to meet a condition of increased load, the incoming fuel will have to purge the passages of air before fuel under the desired pressure is obtained at the metering orifice. This of course renders the engine sluggish in its response to operation of the throttle.

The present apparatus meets this problem by causing a flow of fuel through the passages prior to the opening of the metering orifice and thus purging the system of air. While a continuous flow of fuel past the metering orifice would maintain the system purged of air, it is unnecessary to maintain such a constant flow, provided the flow starts prior to the opening of the metering orifices. In this Way the total amount of fuel supplied may be reduced.

The fuel supply apparatus comprises generally a fuel pump adapted to draw fuel from a supply tank, with a pressure regulator provided on the delivery side of the fuel pump to regulate the pressure of the fuel in a predetermined manner so as to provide the desired torque curve for the engine. Such fuel under pressure is supplied to injectors, one for each cylinder of the engine, and provision is made so that the fuel may flow past the metering orifices in the injectors and thence to a drain to carry away any air entering the passages in the injectors. The injectors are also provided with restrictive orifices beyond the metering orifices to cooperate with the pump and pressure regulator in providing the desired pressure at the metering orifices. The metering orifices are adapted to be opened and closed by engineroperated plungers in the injectors, and the movement of such plungers is also utilized to open and close the fuel supply passages in the injectors to prevent flow of fuel therein during a portion of the time when the metering orifices are closed. This reduces the requirements on the pump so that it may be of smaller size than if it were constantly causing a flow of fuel through the injectors to the drain. A hand throttle and a governor-operated valve are interposed in the connection between the pressure regulator and the injectors.

To facilitate understanding of the invention, the apparatus is shown diagrammatically in Figure 5 where the fuel tank is indicated at It Extending from the tank It is a line 11 leading to a pump 12 which is preferably a gear pump having a rate of delivery varying with the speed at which it is driven. The gear pump 12 is adapted to be driven bythe engine, in the present instance, and thus has a delivery rate varying with the speed of the engine. A hand-operated valve 13 is provided to shut down the engine when desired and may be interposed in the line 11 between the tank 18 and the pump 12.

The fuel delivered by the pump passes through a line- 14 which may have a filter 15. therein and which is connected. to a pressure regulator indicated generally at 16. The pressure regulator is adapted to bypass a portion of the fuel delivered by the pump and thus cooperate with the pump and with restrictive orifices in the injectors, hereinafter described, to provide a predetermined variation in the pressure of the fuel applied to the metering orifices in the injectors. The pressure regulator 16 is of the type comprising a member movable by the pressure of the fuel supplied by the pump, the movement of the member being resisted by a spring. The pressure regulator is provided with a bypassing orifice 17 and the bypassed fuel may be returned through a line 2% to the intake side of the pump 12. The fiow through the orifice 17 varies with the pressure of the fuel supplied by the pump.

From the pressure regulator 16, fuel fiows through a passage 21 to a manually operable throttle indicated at 22. The throttle is adapted to be moved between two positions, namely, anidling position and a full position. The throttle 22 is provided with a transverse passage 23 communicating with the passage. 21 at all positions of the throttle and adapted to register with a delivery passage 24 for supplying fuel to the engine at speeds aboveidling. At full throttle, the passage 23 opens fully into the passage 24 and by rotating the throttle, communication between the passages 23 and 24 is gradually reduced as the throttle is moved towards idling position and finally communication therebetween is shut off when the throttle reaches idle position. For operating the. engine at idling speed, the throttle is provided with a longitudinal passage 25 communicating with one end of the transverse passage 23. The longitudinal passage 25 opens into an annular'passage 26 in the throttle which in turn communicates with a passage 27.

The flow of fuel through the passages 24 and 27 is controlled by a governor operated valve indicated generally at 30. The valve 3%) is adapted to be actuated by a governor driven in timed relation with the engine and comprises a valve body 31 and a movable valve member 32, The governor, as the speed of the engine increases, tends to move the valve member 32 to the right as shown in Fig. 5 and a spring means indicated generally at 33 is provided to resist movement of the valve member 32.

The valve. body 31 is provided with an idling supply passage 34 connected to the passage 27, and with an operating supply passage 35 connected with the passage 24. The valve body 31 is also provided with a delivery passage 36 and all three

passages

34, 35 and 36 open into a bore in the valve body in which the valve member 32 operates. The valve member 32 isprovided with a reduced portion 37 adjacent the

passages

34, 35 and 36 to provide communication from the

respective supply passages

34 and 35 t0 the delivery passage 36.

The movement of the valve member 32, under the control of the governor and the spring means 33, is such that, when the throttle 22 is set at idling position so that communication between the passages 23 and 24 is shut off, the shoulder 40 on the valve member 32 will control the flow of fuel through the idling supply passage 34 to maintain the proper supply of fuel to the'engine for operation at idling speed. If the engine tends to exceed idling speed, the shoulder 46 will cut olf the flow from the supply passage 3 and thus prevent the engine from exceeding such speed. As the speed of the engine is reduced, the valve member 32 will thereby be moved to the left to again open the passage to permit flow of fuel therefrom to the delivery passage 36. When the throttle 22 is shifted to a position above its idling speed position, the increased engine speed causes the governor to shift the valve member 32 to shut off the passage 34 out fuel then fiows from the throttle through the passage 24 and the operating supply passage 35. At the maximum speed of the engine, the shoulder 48 will move to close the supply passage 35 and thus prevent the engine from exceeding such maximum.

From the delivery passage 36, fuel flows through a passage 41 to a common supply rail or header 42 connected to all of the injectors, indicated at 43. As heretofore stated, each injector is provided with passages for permitting the fiow of fuel therethrough from the common rail orsupply line 42. Within each injector is a metering orifice for metering the fuel from the fuel sup plied by the rail 42. The quantity of fuel supplied to each injector is in excess of thatpassing through the metering orifice and the remainder of the fuel is carried by suitable passages in each injector to a, common re turn rail or line 44 which is connected by a line 45 to the tank 10 so that such fuel may be returned to the tank. Each injector also includes a restrictive orifice beyond the metering orifice, which cooperates with the pump 12 and the pressure regulator 16 in providingv predetermined variations in the fuel pressure to control the metering of the fuel throughout the speed range of the engine.

The governor-operated valve 3i} also includes a drain passage 46 which is adapted to be opened by the valve member 32 when the latter has moved to the maximum speed position. At this position, flow of fuel through the operating supply passage 35, has been cut ofi by the. Shoulder- 46 and communication is established between the drain passage 46 and the delivery passage 36 by means of the reduced portion 37 on the valve member to immediately relieve the pressure in the passage 41 leading to the injectors. The pressure at the metering orifices is thus immediately relieved, so that, supply of fuel to the engineis quickly reduced, thus preventing overspeeding of the engine. The drain passage 46 opens into the, housing of the fuel supply unit and, overflow from. the housing is carried away by a fitting 47' connected to the line 45 returningfuel to the tank 10;

When the flow of fuel through the operating supply passage 35 has been cut elf by the valve member 32, the pump. of course is still operating and the fuel delivered thereby tends. to. build up the pressure at the pressure regulator 15;. To provide for an outlet of such fuel and thereby prevent excessive; pressures, the pressure regulater is provided with a; dumping opening 50 which under the pressure existing at that time permits the. entire output of thetm p 2. obe r t r ed through the ne 0 to the intake side. of the pump; 7

From the foregoing description, the general layout of the present fuel supply system can be seen. The actual structure embodying this layrut is shown in Figs. 1 to 4, and includes a fuel supply unit in which the pump 12, the pressure regulator 16, the throttle 22, and the governor operated valve 30 are incorporated. The tank of course is separate from such unit and the injectors 43 are mounted in the respective cylinders of the engine so that the unit is thus connected by the line 11 to the tank 10 and by the common rail or supply line 42 to the injectors. The supply unit is also connected by the fitting 47 to the return line 45.

As shown in Figs. 1 to 4 inclusive, the fuel supply unit comprises a housing indicated generally at 51 and comprising a central section 52 and an end section 53. The pump 12 is adapted to be mounted in a separate housing 54 (see Figs. 1 and 3) secured to the right hand end of the central section 52 of the main housing. The pump 12 thus may be readily removed for servicing without the necessity of dismantling the entire unit.

The pump 12 is of the gear type and is adapted to be driven by a shaft 55 having one end arranged to extend into the central section 52 of the main housing and provided with a coupling 56 for connection with a main drive shaft 57. The latter extends through the central section 52 and the end section 53 and is provided at its outer end with a coupling 60 adapted to be driven by the engine. The intake of the pump 12 is connected to the tank 10 through the line 11 shown in Fig. l, the shut off valve 13 also being shown in this figure.

If it is desired to provide a tachometer with the engine. the drive therefor may be obtained from the shaft 57. Thus, a spiral gear 58 may be mounted on the shaft 57 within the central housing section 52 (see Figs. 2 and 3) to mesh with a pinion carried on the lower end of a tachometer drive shaft 59 shown in Fig. 2 and extending upwardly therefrom.

The outlet of the pump 12 61 leading to a recess connects with a passage 62 formed in the main section 52 and the filter is mounted in the recess 62. From the filter 15, the fuel is permitted to flow through a passage 63 (see Fig. 4) provided in the main section 52 and extending to the inner end of a bore 64 formed in the central section 52 to receive the pressure regulator 16. The outer end of the bore 64 is enlarged as at 65, and the pressure regulator comprises a sleeve 66 mounted in the inner portion of the bore 64 and having a flange 67 seated in the enlarged portion 65. The sleeve 66 is held in place by a cup shaped cap 79 and within the sleeve is a slidable regulating member 71 of tubular form and having its inner end open to the interior of the bore 64 so that fuel supplied by the passage 63 may enter the interior of the regulating member 71. The regulating member is provided with a flange 72 adapted to seat against the fiange 67 of the sleeve 66 and is urged toward such seating engagement by a spring 73 located within the cup shaped cap 70. The bypassing orifice 17 of the pressure regulator is formed in the regulating member 71 by a plurality of radial holes therein and the effective area thereof may be varied by a pin 74 threaded in the outer end of the regulating member 71 and having its inner end extending adjacent the holes constituting the bypassing orifice 17. Thus, by adjusting the position of the pin 74 in the regulating member 71, the effective area of the bypassing orifice 17 may be varied.

With the foregoing construction, the pressure of the fuel supplied by the pump 12 and entering the inner end of the bore 64 will tend to force the regulating member 71 to the right, as viewed in Fig. 4, against the pressure of the spring 73 until the bypassing orifice 17 moves to the right of the flange 67 on the sleeve 66 to permit a portion of the fuel to be bypassed through the interior of the supply member 71 and the orifice 17 to the interior of the cap 70. The cap 70 is suitably apertured, as at 75, to communicate with the passage (see Fig. 3).

formed in the central section 52 and leading to the intake or" the pump 12 so that the bypassed fuel may thus be returned to the intake of the pump. The regulating member 71 is also provided with the dumping aperture 50 which, when the regulating member 71 is moved sulficiently to the right as shown in Fig. 4, will permit the entire output of the pump 12 to be returned to the intake side thereof, as heretofore described.

The fuel which flows past the pressure regulator is conducted by the passage 21 (see Fig. 4) to the throttle 22. The throttle 22 is adapted to be mounted in a bore in the central section 52 of the supply unit housing and comprises a sleeve or bushing 81 mounted therein. Within the bushing is a rotatable throttle member 82 which projects at one end to the exterior of the housing and has secured thereon a lever 83 by which the throttle member 82 may be rocked. The bushing 81 is provided with a port 84 registering with the passage 21 to receive fuel therefrom. The bushing 81 is also provided with a port 85 registering with the passage 24 for supplying the fuel for engine speeds above idling, and a port 85 registering with the passage 27 for supplying fuel at idling speed. The port 84 communicates with the longitudinally extending passage 25 formed by providing a fiat side on the throttle member 82, the passage 25 thus being open to the port 84 for all positions of the throttle member 82. The transverse passage 23 in the throttle member 82 provides communication between the ports 84 and 85 but is so dimensioned relative to the port 85 that when the throttle tion, the passage 23 is out of register with the port 85 so that no fuel can flow therethrough. When the throttle member 82 is moved to its fully opened position, the transverse passage 23 is fully opened to the port 85. Thus, by the rocking movement of the throttle member 82, the flow of fuel to the engine may be controlled by the extent to which the transverse passage 23 registers with the port 85, thereby permitting the hand throttle to regulate the speed of the engine between idling speed and maximum speed.

The flattened portion on the throttle member 82 providing the passage 25 extends longitudinally to a portion 87 of reduced diameter forming the annular passage 26 to provide communication between the longitudinal passage 25 and the port 86 registering with the passage 27. Fuel can thus flow from the passage 21 through the port 84, the passage 25, the annular the reduced portion 87, to the port 86 and the passage 2'7 for operation of the engine at idling speed.

As heretofore mentioned, the governor-operated valve 38 (see Figs. 3 and 4) comprises a valve body 31 and a movable valve member 32. The valve member 32 is adapted to be shifted by a governor, indicated generally at 90, and the movement of the valve member 32 by the governor is opposed by the spring means 33.

The governor, in this instance, comprises a pair of weights 91 pivotally mounted as at 92 on a carrier 93. The carrier 93 is mounted on a shaft 94 journaled in a bearing 95 mounted in the end section 53 of the housing, the shaft 94 projecting into the interior of the central section 52 where the carrier 93 is located. The shaft be driven from the The governor is engine in timed relation therewith.

The governor weights 91 are provided with inwardly projecting arms 101) which engage a collar 101 formed on the adjacent end of the valve member 32 so that, when the weights 91 move outwardly on increase in speed, the valve member 32 will be moved to the right as viewed in Figure 3. In order to avoid any possibility of the valve member 32 sticking in the valve body 31, the valve member 32 is constantly rotated. To this end, the collar 191 on the valve member 32 carries a pair of thus driven by the member 82 is turned to idle speed posiflange portions 102 which straddle the inner ends of the arms 100 and thus are rotated by the rotation of the carrier 93.

The governor is adapted to control the flow of fuel to the engine at idling speed and to limit the flow of fuel at the maximum engine speed, and the spring means 33 is constructed in a manner to effect this result. this purpose, the spring means 33 comprises a cylindrical casing 103 secured in the main section 52. Within the casing 103 is slidably mounted a sleeve 104 which in turn has mounted therein a plunger 105 abutting the end of the movable valve member 32. The sleeve 104 has a reduced portion 106 at its outer end to provide a shoulder 107 against which is seated a spring 110 located within the outer end. of the casing 103. The other end of the spring 110. seats. against a collar 111 anchored in the outer end of the casing 103. Mounted within the sleeve 104 is a second spring 112 which seats at one end against the plunger 105 and at its other end against a Washer 113 mounted on a screw 114 threaded in the outer end of the reduced portion 106 of the sleeve 104. The casing 103 projects beyond the. central housing section 52 and is enclosed by a cover 118 removably secured to the section 52 so that access may be readily obtained to the screw 114 for adjustingthe idling speed.

The spring 112 resists movement of the valve member 32 by the governor at idling speed, while the spring 110 is adapted to be compressed by the governor when the speed of the engine reaches maximum. Thus, when the engine is operating at idling speed, the spring 113 is of such strength that movement of the valve member 32 by the action of the governor weights 91 is limited to such extent that the shoulder 40 on the valve member will out 01f flow through the idling speed supply passage 34 at the desired idling speed. Adjustment of the engine speed at which this occurs may be made by turning the screw 114 in the sleeve 104 to vary the pressure exerted by the spring 112.

When the throttle is moved above its idling speed position to increase the engine speed, the action of the centrifugal weights 91 of; the governor is suflicient to further compress the spring 112 by movement of the plunger 105 to the right, as viewed in Figure 3. At a speed slightly above idling speed, the plunger 105 has been moved sufilciently to the right to engage an interior shoulder 115 formed within the sleeve 104. Thus, the force of the governor weights for further increases in engine speed is exerted against the sleeve 104, since the plunger 105 is in engagement therewith. Movement of the plunger 105 under the action of the governor weights is thereafter opposed by the spring 110. As the speed of the engine approaches a predetermined maximum, the force, exerted bythe governor weights is suflicient to compress the spring 110, thus permitting the valve member 32 to move farther to the right, as viewed in Fig. 3, to shut oil the flow of fuel through the operating supply passage 35, as heretofore generally described.

The valve body 31 of the governor-operated valve is preferably in the form of a cylindrical member mounted with a press fit in a bore, in the interior of the main body section 52 of the supply unit housing. The casing 103 of the spring means 33 also extends into the bore and is provided with a flange 116 seated in the bottom of the bore and held in place by the valve body 31. The valve member 32 extends through a bore 117 formed in the valve body 31 and thus connects the governor 90 with the spring means 33. The idling speed supply passage 34, heretofore described in connection with the diagrammatic view, Fig. 5, is shown in Figure 3 and opens into the bore 117 so that flow therethroughmay be controlled bythe shoulder 40 on the valve. member 32 The operating supply passage 35, which is shown in the diagrammatic view of Fig. v as comprising a single passage, is preferably formed in the actual structure by a For transverse groove 120 (see, Fig. 4) on one side of the valve body 31. The bore. in the central housing section 52 in which the valve body 31 is mounted intersects the pa sage 24 extending from the throttle 22 and the transverse groove 120 permits flow of fuel from the passage 24 into the valve body 31.- Extending radially from the transverse groove 120 are a plurality of drilled radial holes 121 opening into the bore 117 in which the valve member 32 ismounted. The reduced portion 37 on the valve member is located at the inner ends of the radial holes 121 so that the fuel can flow around the reduced portion 37.

The delivery passage 36 in the valve member 32 is also formed by a plurality of radially drilled holes 122 extend? ing from the bore 117 on the opposite side of the valve member from the holes 121. The holes 122 open into a second transverse groove 123 in the valve body 31, and the central section 52 of the housing is provided with the passage 41 which extends from the transverse groove 123 first horizontally and then vertically in the housing section 52 to connect with a pipe 124 leading to the common supply rail 42 for the injectors.

As heretofore described, the valve body 31 also inciudes the passage 46 for draining, fuel from the passage 41 when the governor causes the valve member 32 to shut oft how of fuel from the operating supply passages comprising the holes 121. The passage 46 in the valve body 31 is shown in Fig. 3 and extends from the bore 117 in which the valve member 32 is mounted to a passage 125 formed in and extending longitudinally of the valve body 31 and emptying into the interior of the housing. As heretofore described, when the shoulder 40 of the valve member 32 cuts oil flow through the operating supply passage 35 comprising the holes 121, the passage is opened by the valve member so that the pressure of the fuel in the passage 41 leading to the injectors may be relieved by draining the fuel into the interior of the housing. The fuel which is thus drained into the housing, together with any fuel collected in the housing from leakage, fills the interior of the housing and may overflow therefrom through the fitting 47 on the top of the central section 52 for return to the fuel tank 10 through the line 45 which also carries the return from the injectors.

The common rail or header 42 by which fuel is supplied to all of the injectors 43 is connected to the individual injectors by branch supply lines 126 leading to passages formed Within the injectors and extending therethrough for connection with the return rail 44 by means of branch return lines 127. The fuel passage extending through each injector comprises generally a supply portion, an intermediate portion, and a return portion. The supply portion of the passage, in the form of injector, shown in Figs. 10, and '11, comprises a drilled passage 130 extending generally radially of the injector and connecting with a second drilled passage 131 extending generally longitudinally thereof. At its lower end, the drilled passage 131 opens into a smaller drilled passage 132 extending to the lower end of the injector body 133 and opening into an annular chamber or passage 1'34 constituting the intermediate portion of the complete passage'through the injector. The annular passage 134 is formed between a reduced lower end 135' on the injector body and a conical nozzle member 136'.

The injector body 133 is provided with a centrally located plunger bore 140 opening at its lower end into a conical fuel chamber 141 formed in the nozzle member 136. At its lower end, the nozzle member 136 is provided with a central projection 142 through which a plurality of small radial holes 143 are drilled to extend from the fuel chamber 141 and constituting the nozzle proper for discharging fuel into the engine cylinder.

Fuel is supplied to the fuel chamber 141 in the nozzle member through a metering; orifice 144 extending radialiy from the annular passage 134 through the reduced lower end 135 of the injector body to the interior of the plunger bore 140. Within the plunger bore 140 is a longitudinally reciprocable plunger 145 having a conical lower end 146 adapted to fit and fully occuoy the fuel chamber 141 in the nozzle member when the plunger is in its lowermost position, as shown in Figure 10. During reciprocation of the plunger 145, the lower conical end 146 thereof is raised sufiiciently, as shown in Figure 11, to admit fuel through the metering orifice 144 into the fuel chamber 141, the pressure of the fuel in the annular passage 134 determining the quantity of fuel flowing into the fuel chamber 141. When the plunger 145 is next moved downwardly, the metering orifice 144 is closed thereby and the fuel which has entered the fuel chamber 141 is forced outwardly through the radial holes 143 in the nozzle into the cylinder.

The return portion of the passage through each injector includes a restrictive orifice which cooperates with the fuel pump 12 and the pressure regulator 16 in determing the pressure of the fuel in the annular passage 134 and hence the pressure of the fuel applied to the metering orifice 144. Thus the return portion includes a passage 150 extending longitudinally of the injector and upwardly from the annular passage 134 and having a reduced portion or restrictive orifice 151 at its upper end. Such restriction in the return portion of the fuel passage is correlated in size to the capacity of the pump and the action of the pressure regulator so that the desired pressure is obtained in the annular passage 134.

As heretofore mentioned, it is unnecessary to have a constant flow of fuel through the passages in the injector since such a constant flow would increase the demands upon the pump. It is necessary to have a flow through these passages in the injector only during the time that the metering orifice 144 is opened by the plunger 145 and sufiiciently before such opening in order that any air in the passages may be purged and solid fuel is present at the metering orifice when it is opened. To this end, the return portion of the passage through this form of injector is adapted to be opened and closed to alternately permit and prevent flow of fuel therethrough and preferably the movement of the plunger 145 is utilized for this purpose, with a portion of the plunger bore included as part of the return passage. Thus, the restrictive orifice 151 opens into a cross passage 152 extending into the plunger bore 140. At some distance above the cross passage 152 is a second cross passage 153 extending from the plunger bore 140 and communicating with a vertical passage 154. Adjacent the upper end of the injector, the passage 154 communicates with a radial passage 155 connected to the branch return line 127 for discharging fuel into the return rail or header 44 to be carried back to the tank by the line 45.

Fuel is permitted to flow from the cross passage '152' to the second cross passage 153 through the plunger bore 140 under the control of the movement of the plunger 145. To this end, the plunger 145 is provided intermediate its ends with a reduced portion 156 which extends below the cross passage 152 for all positions of the plunger. The reduced portion 156 of the plunger extends upwardly to a shoulder 157 which is adapted to open and close the second cross passage 153 during pre determined portions of the cycle of operation.

Since it is desired to open the return portion of the passage through the injector prior to the time when the metering orifice 144 is opened, the shoulder157 on the injector plunger 145 is so positioned that it begins to open the cross passage 153 shortly before the plunger opens the metering orifice 144. Thus, as soon as the cross passage 153 is open, as shown in Fig. 11, fuel starts to flow through the various passages in the injector and any air which may have accumulated in the annular pas sage 134 by being forced outwardly through the metering orifice 144 is carried away, by the incoming flow of fuel, through the return portion so that solid fuel is present in the annular passage 134 and particularly at the metering orifice 144. Thus, the return portion is opened shortly before the metering orifice is opened so that any air in the passages may be purged therefrom. This flow continues until after the metering orifice is closed by the plunger since the shoulder 157 will not completely close the cross passage 153 until after the meeting orifice has been closed.

To get rid of any fuel leaking upwardly along the plunger, an annular drain groove is cut in the plunger a short distance above the shoulder 157 and when the shoulder 157 closes the cross passage 153, the groove 160 opens into the cross passage 153, as shown in Fig. 10, to permit any leakage to pass out through the

passages

153, 154 and 155 to be returned to the fuel tank.

The plungers 145 of the injectors are adapted to be operated by the engine and means for doing this is shown diagrammatically in Figure 11. Thus, the upper end of the plunger 145 is engaged by a rocker arm 161 pivoted at 162 intermediate its ends, and the other end is engaged by a push rod 163 actuated by an engine driven cam 164. The reciprocation of the plungers 145 thus occurs in fixed timed relation to the cycle of the engine.

The form of injector shown in Figs. 12 and 13 is generally similar to the form heretofore described but provides better assurance that none of the air that may collect in the fuel passages adjacent the nozzle will work back into the common supply line 42. Thus the form of injector shown in Figs. 12 and 13 is provided with a fuel passage extending therethrough, which comprises generally a supply portion, an intermediate portion, and a return portion. This form of injector is also provided with a fuel chamber adjacent the nozzle, and a metering orifice for admitting fuel from the intermediate portion of the supply passage into said chamber. The return portion of the fuel passage in the injector also has a restrictive orifice which cooperates with the pressure regulator 16 and the pump 12 in providing the desired range of pressure in the fuel applied to the metering orifice. The main difference in this form of injector lies in the fact that the supply portion of the fuel passage is adapted to be opened and closed in timed relation to the opening and closing of the metering orifice. By this means, air forced into the chamber in the nozzle is definitely prevented from Working back into the supply line 42.

To describe the form of injector shown in Figs. 12 and 13 in detail, each injector is provided with a radial passage connected to the common supply line 42. The radial passage 170 at its inner end opens into a vertically extending passage 171 constituting a part of the supply portion of the fuel passage through the injector. The passage 171 extends part way down the injector and opens into a transverse passage 172 which extends inwardly to a plunger bore 173 formed in the injector body. A short distance below the transverse passage 172 is a second transverse passage 174 which also extends from the plunger bore 173 and which communicates with a small downwardly extending passage 175. The latter opens at'its lower end into an annular passage 176 constituting the intermediate portion or chamber of the fuel passage through the injector. The annular chamber 176 is formed between a reduced portion on the lower end of the injector body and a nozzle member 177. The nozzle member 177 is provided with a fuel chamber 180 similar to the chamber in the other form of injector and constituting the lower end of the plunger bore 173.

Fuel is supplied to the fuel chamber 180 in the nozzle through a metering orifice 181 extending radially inward from the annular chamber 176 to the plunger bore 173. Within the bore 173 is a plunger 182 which extends upwardly therethrough and which has a conical lower end 183 adapted to fit and fully occupy the fuel chamber 180. The plunger 182 is reciprocably mounted within the plunger bore and when the plunger is in its raised position, as shown in Fig. 13, the conical lowerend thereof is at a sufficient height to admit fuel through the metering rifi 181 into he fuel hambe 180; the pr ure f e of this form comprises an upwardly extending passage 184 having a reduced portion 185 at its upper end, constituting a restrictive orifice. This orifice cooperates with the, pressure regulator 16 and the pump 12 to provide the desired pressures in the annular chamber 176 to effect desired metering of fuel through the metering orifice 1 81. Beyond the, restrictive orifice 185, the passage is enlarged as at 186 and extends upwardly to a radial passage 187 which is connected to the return line 44 common to all of the injectors.

As heretofore. mentioned, the supply portion of the fuel passage through this form of injector is provided with means for opening and closing such portion in timed relation to the opening and closing of the metering orifice 181. To this end, the plunger 182 is provided with a reduced portion 190 intermediate its ends and located ad-.

jacent the transverse passages 172 and 174. The reduced portion 190 is of sufiicient length and is so positioned that when the plunger 182 is in its raised position, as shown in Fig. 13, communication is provided between the two passages 172 and 174 by the space within the plunger bore 171 around the reduced portion 199. The upper end of the reduced portion 190 provides a shoulder 191 which is adapted to close the transverse passage 172. shortly after the plunger 182 has closed the metering orifice 181. With this position of the shoulder 191, the transverse passage 172 will be'opened to communicate with the passage 174 through the plunger bore 173 prior to the opening of the metering orifice 181 Thus the fuel which is supplied under pressure to the injectors by the common supply line 42, starts to flow through the passages in each injector just prior to the time that the metering orifice 181 is opened, and such flow is stopped shortly after plunger 182 moves downwardlytto close the metering orifice 181. With this arrangement, air which may accumulate within the lower portions of the fuel passages in the injector will be prevented from working upwardly into the supply line, since the communication therewith is cut ofi" by closing the transverse passage 172. When the plunger again opens the transverse passage 172, the fiow of fuel through the passages will carry away any air that may remain therein. However, during the period when the passage 172 is closed, any air; that may have entered the fuel passages in the injector, particularly the portions of the passage in the lower end thereof, is; free to pass to the return line 44 since the return passage in the injector remains continuously open throughout the operation of the injector. Thus there is very little tendency for air to accumulate in the portions of the fuel passage in the lower end of the injector and by closing the supply portion of the fuel passage, it is definitely prevented from working upwardly into the supply line.

With an injector of the form shown in Figs. 12, and 13, no leakage collecting groove is necessary. The annular space within the plunger bore 173 about the reduced portion 190 of the plu ger is subjected to fuel under pressure only for the short period of time when the plunger is raised to admit fuel through the metering. orifice and consequently very little leakage along the, plunger can occur during that period of time. When the plunger is in its lowermost position, the annular space about the reduced portion 190 is in communication with he return passage through the cross passage 174, the vertical pas-. sage 175,, and the annular chamber 176; Thus at that tim f in. h ann l pace ab ut the reduced. portion 1% has been, reduced in pressure so that, no leakage will occur along the plunger.

- Io eser be the oper ion f th app h d grammatie views of Figs. 6 to 9, inclusive, have been included to show various positions of the governor-operated valve 30 in order that varying conditions of operation may be discussed. Considering first the condition where the engine is stopped, the position of the parts of the governor-operated-valve for such condition is shown in Figs. 3 and 6, With the engine stopped, the governor weights 91 of course exert no force against the valve member; 32 so that the spring means 33 holds the valve member to its extreme left position, as shown in those figures. In this position, it will be noted that the reduced portion 37 onthe valve member 32 has moved to the left of the delivery passage 36 so that the latter is closed, thus preventing fuel from draining from the line 41 and the common supply rail 42. The shoulder 40 on the valve member is to the left of the idling speed supply passage 34 in the valve body 31, and the throttle 22 is in its idling speed position so that the fuel previously supplied by the pump 12 before the engine was stopped fills the passages from the pump through to the annular passage provided by the reduced portion 37 of the valve member 32. Since the pump is not operating, the spring 73 of the pressure regulator 16 has shifted the regulating member 71 so that the lay-passing orifice 17 is closed. Thus, all of the passages from the pump to the governoroperated valve are filled with fuel ready for operation when the engine is started, and the passages extending from the governor-operated valve to the injectors are likewise filled with fuel.

On starting the engine, the main shaft 57 will be rotated through its driving connection with the engine and consequently the governor weights 91 will start to move outwardly. The force exerted by these weights begins to compress the spring 112 in the spring means 33 by shifting the valve member 32 to the right. Movement of the valve member 32 to the right opens the delivery passage 36 so that communication is established between the idling speed supply passage 34 and the delivery passage 35. Fuel will thereby be supplied to the injectors 43 so that the engine may start. As the speed of the engine increases on starting, the governor weights 91 move outwardly still, farther to shift the valve member 32 farther to the right against the opposing pressure of the spring 112. At normal idling speed, the shoulder 40 is adjacent the opening of the idling speed supply passage 34 into the bore117 for the valve member 32 and fuel thus continues to flow across the bore 117 to the delivery passage 36 so long as this speed is maintained. However, should the speed of the engine increase above the. desired idling speed, the shoulder 40 on the valve member 32 will shift farther to the right and partially or comple ely dos th id ing spe d pp y P g thus decreasing or stopping the supply of fuel to the engine so. that its speed will be reduced until the desired idling speed is attained and the shoulder iii again opens the idling speed supply passage 34. During this condition of operation, the operating supply passage 35 is also open into the bore 117 but no fuel flows therethrough because the transverse passage 23 in the throttle member 82 is out of register with thev port 85.

As heretofore mentioneithe speed at which the engine idles may be adjusted as desired by means of the screw 114 in the spring means 33 By turning the screw to shift it to the left as. shown in Fig. 3, the pressure on the spring 112 will be increased, thereby requiring a higher speed of rotation to, effect a given movement by the governor weights 9.1 to the valve member 32. Thus, the she der 40. will cut oif flow through the, idling speed suppiy passage 34. at a higher engine speed. Of course, adjusting the screw 114 to the, right will lower the speed at which the engine idles, since less force is required to compress spr 112., I

When it is. desired to. increase. the speed of the engine above idling speed, the lever 83. of the throttle 22 is,

13 turned away from idling speed position toward the maximum speed position to shift the transverse passage 23 of the throttle member 82 into register with the port 85 so that fuel may fiow through the operating supply passage 35 in the valve body 31. The increased speed of the engine causes the governor weights 91 to exert a greater force on the valve member 32 so that the shoulder 40 closes off the idling speed supply passage 34 in the valve body 31. Thus, fuel is supplied to the injectors solely through the operating speed supply passage 35 for engine speeds above idling speed. During such movement of the valve member 32 to the right, the idling speed spring 112 is further compressed.

When the engine is operating under load, the throttle is shifted to its fully open position and the position of the valve member 32 in relation to the supply passage 35 is shown in Fig. 7. Thus, the idling speed supply passage 34 is shown as being closed and fuel is permitted to flow from the operating supply passage 35 around the reduced portion 37 of the valve member 32 to the delivery passage 36 for supplying the injectors with fuel. When the throttle is fully opened and the load on the engine is relieved to such an extent that its speed would tend to exceed a predetermined maximum, the supply of fuel to the engine is cut off so as to prevent excessive speed. Under this condition, the governor weights 91 exert sufficient force on the valve member 32 to compress the spring 112 until the plunger 105 engages the shoulder 115 on the sleeve 104, and also to begin to compress the spring 110. Under such conditions, the valve member 32 moves still farther to the right to the position shown in Fig. 8 and the shoulder 40 on the valve member 32 first reduces and then cuts off flow through the operating supply passage 35. Thus, no fuel can flow to the engine.

At the time when such flow is stopped to limit the speed of the engine to a predetermined maximum, the pressure of the fuel in the lines leading to the injectors is also relieved so as to promptly stop flow through the metering orifices of the injectors. To this end, the reduced portion 37 on the valve member 32 opens the drain passage 46 so that communication is provided between the delivery pasage 36 and the drain passage 46 to relieve the pressure of the fuel in the injectors. The fuel passing out through the drain passage 46 flows through the longitudinal passage 125 into the interior of the housing section 52, and the overflow from the latter is carried through the fitting 47 and the line 45 to the tank 10. When the speed of the engine is reduced below its maximum by stoppage of the supply of fuel, the valve member 32 is forced to the left by the spring 110, and the drain passage 46 is closed and the operating supply passage 35 is again opened for continued flow of fuel to the engine.

When the operating supply passage 35 is closed because of the speed of the engine, the pump of course continues to deliver fuel and the pressure of the fuel tends to build up in the pressure regulator 16. Such increase in pressure moves the regulating member 71 to the right, as shown in Fig. 4, far enough to open the dumping aperture 50 and permit the entire delivery from the pump to be bypassed back to the intake side of the pump, thereby avoiding excessive pressures in the passages between the pump and the governor-operated valve. When the speed of the engine drops below maximum and the operating supply passage 35 is again opened, the pressure in the pressure regulator drops sufficiently to cause the regulating member 71 to be shifted by its spring 73 so as to close the dumping aperture 50, leaving only the orifice 17 in the pressure regulator open for bypassing fuel. The pin 74 may be adjusted to control the effective area of the orifice 17 so that the pressure at the metering orifices will result in the desired charges of-fuel being supplied to the cylinders to control the engine power.

The plungers in the injectors are reciprocated in timed relation with the cycle of the engine. Thus, each plunger 145, in the form of injector shown in Figs. 10 and 11, is raised to open the metering orifice 144 at the time that the piston in the associated cylinder is on a compression stroke. The pressure of the fuel in the annular passage 134 in the injector causes a flow of a predetermined quantity of fuel through the metering orifice into the fuel chamber 141 within the time that the metering orifice is open. On the subsequent downstroke of the injector plunger 145, the metering orifice is closed thereby and the fuel in the fuel chamber 141 is forced outwardly through the radial holes 143 into the cylinder for combustion therein.

The restrictive orifices 151 in the return portion of the passage through the injectors cooperate with the pump 12 and the pressure regulator 16 to provide the desired pressures in the annular passages 134 to effect flow through the metering orifices that will result in the desired torque curve for the engine. Since the size of the restrictive orifices 151 is fixed and the pump 12 supplies fuel at a predetermined rate varying with the speed of the engine, the pressure regulator 16 may be constructed so as to provide the desired variation in the pressure of the fuel at the metering orifices throughout the speed range of the engine.

Since the desired metering of fuel by the metering orifices 144 can be obtained only if solid fuel free of any air is present in the annular passages 134 in the injectors, any air that may be forced outwardly through the metering orifices because of the compression in the cylinders must be purged before the metering orifices are opened. While a constant fiow of fuel through the injectors would carry away such air, such constant flow would increase the demand on the pump 12 in order to maintain the constant flow. Since air cannot pass outwardly through the metering orifices during the periods of time when these orifices are closed by their plungers, it is unnecessary to maintain a flow through the injector passages during such periods of time. Consequently, with the form of injector shown in Figs. 10 and 11, the shoulder 157 on the injector plunger 145, in each injector, stops the flow through the injector by closing the cross passage 153, and closure of this passage occurs after the metering orifice has been closed by the plun'ger.

Shortly before the metering orifice is opened by the plunger, the flow through the injector is again permitted to start by movement of the shoulder 157 to open the cross passage 153. Since such flow starts prior to the opening of the metering orifice, any air that has accumulated in the annular passage 134 is carried out through the return portion of the injector passage by the inflow of fuel from the pump. Consequently when the metering orifice is opened, the annular passage 134 has been purged of air and solid fuel under pressure is present at the metering orifice to effect metering of the desired charge to the cylinder.

When the plunger 145 moves downwardly and the shoulder 157 closes the cross passage 153, the pressure of the fuel in the plunger bore 1 40 around the reduced portion 156 of the plunger is relatively high since at that time it approximates the pressure in the annular passage 134 which effects themetering. Such pressure of the fuel in the plunger bore would tend to produce leakage along the plunger but, by virtue of the groove 160 in the plunger, such leakage is collected therein and may pass into the cross passage 153 where the pressure is low and be carried back to the fuel tank 10. When the plunger is moved upwardly to permit flow through the portion of the plunger 140 adjacentv the reduced portion 156 of the plunger, the pressure of the fuel therein is lower than the pressure of the fuel in the annular passage 134, since the plunger bore is then in communication with the cross passage 153 and the restrictive orifice 151 maintains the pressure of the fuel in the annular passage 134 higher than the pressure of the fuelbeyond 'I have provided a novel fuel 15 the restrictive orifice. Thus, when the groove 160 is out of communication with the cross passage 153 very little leakage will occur along the plunger because the pressures are low at that time;

The injectors of the form shown in Figs. 12 and 13 operate in a similar manner to the other form of injectors, the main difference lying chiefly in the fact that, with this form of injector, the supply portion of the fuel passage therethrough is adapted to be opened and closed by the injector plunger. This form of injector avoids any tendency for air to accumulate in the intermediate chamber 176, since this chamber is continuously connected to the return passage and air passing outwardly through the metering orifice is therefore free to pass to the return line at all times. When the metering orifice 181 is closed, the transverse passage 172 is also closed so that the air cannot work back into the supply line but may freely pass to the return line. When the passage 172 is again opened, the flow of fuel therethrough will carry out any remaining air before the metering orifice 181 is opened.

The fuel returned from the injectors to the common return rail 44 carries all the accumulated air with it and discharges both the fuel and air into the fuel tank 10. To prevent air returned to the tank from building up and thereby producing a back pressure, the tank is vented as at 170 to permit the air to escape and to maintain the pressure in the tank at atmospheric pressure. This also avoids any accumulation of air in the entire system, since the 'fuel withdrawn from the tank by the pump 12 will be freed of air.

From the foregoing description, it will be apparent that supply apparatus in which a predetermined torque curve for the engine is obtained by effecting a predetermined variation in the pressure of the'fuel supplied to the injectors throughout the speed range of the engine. The restrictive action of the orifices in the return passages of the injectors, the variation in delivery of the pump 12 in accordance with the engine speed and the bypassing action of the pressure regulator g 16 are all correlated so that the desired metering of fuel occurs. Moreover, by establishing flow of fuel through the injectors before the metering orifices are opened, any air in the passages is purged so that solid fuel under pressure is present at the metering orifices when they are opened. Consequently the engine is promptly responsive to the operation of the throttle. However, excessive pump capacity is avoided by preventing flow through the injectors during the time when the metering orifices are closed. It will also be apparent that the injectors employed in this apparatus are of a novel construction.

I claim:

1. A fuel supply apparatus for a multi-cylinder internal combusiton engine,'comprising means for supplying fuel under pressure, a manually operable throttle connected to 'said means for receiving fuel therefrom and having an idling speed passage and an operating speed passage, a governor-operated valve having an idling speed passage connected to the idling speed passage of the throttle, an operating speed passage connected to the operating speed passage of the throttle, and a delivery passage to receive fuel from both said idling speed passage and said operating speed passage of said governor-operated valve, a supply line connected to said delivery passage, a return line, and a plurality of injectors, each having a passage connected at its respective ends to said supply and return lines, and a metering orifice extending from said last-mentioned passage and communicating with a cylinder for metering fuel to be injected into the cylinder.

'2. A 'fuel supply apparatus for a multi-cylinder internal combustion engine, comprising means for supplying fuel under pressure, a manually operable throttle connected to said means for receiving fuel therefrom and having an idling speed passage open at all positions of the throttle and an operating speed passage adapted to be opened by movement of throttle .from idle speed position, a governor-operated valve having an idling speed passage connected to the idling speed passage of the throttle and adapted to be closed by said valve when the engine exceeds idling speed, an operating speed passage connected to the operating speed passage of said throttle to receive fuel therefrom at engine speeds above idling speed and adapted to be closed by said valve when the engine speed exceeds a predetermined maximum speed, and a delivery passage for receiving fuel from both of said valve passages, delivery passage, a return line, and a plurality of injectors, each having a passage connected at its respective ends to said supply and return lines, and a metering orifice extending from an intermediate part of said last-mentioned passage and communicating with a cylinder for metering fuel to be injected into the cylinder.

3. A fuel supply apparatus for a multi-cylinder internal combustion engine, comprising means for supplying fuel under pressure, a manually operable throttle connected to said means for receiving fuel therefrom and having a pair of passages connected to said means, one for conducting fuel when the engine'is operating at idling speed and the other for conducting fuel when the engine is operating above idling speed, a governor-operated valve having a pair of passages respectively connected to the pair of passages in the throttle, a delivery passage to receive fuel from both of said valve passages, a drain passage, and a movable valve member, a supply line connected to said delivery passage, a return line, and a plurality of injectors, each having a passage connected at its respective ends to said supply and return lines, a metering orifice extending from the injector passage and communicating with a cylinder, and a restrictive orifice between said metering orifice and said return line cooperating with said first-mentioned means to establish a predetermined pressure in the fuel at said metering orifice, said valve member being adapted, when the engine exceeds a predetermined maximum speed, to close said pair of passages of said valve and to connect said delivery and drain passages to relieve the pressure in said supply line and the injector passages.

4. A fuel supplyapparatus for a multi-cylinder internal combustion engine, comprising a fuel pump, a pressure regulator for by passing a portion of the fuel delivered by the pump to vary the delivery pressure of the pump and having an enlarged opening for dumping the entire delivery of the pump at a predetermined maximum pressure, a governor-operated valve connected to receive fuel from said pump and having a delivery passage, a drain passage, and a movable valve member for controlling the flow of fuel through said valve, a supply line connected to said delivery passage, a return line, and a plurality of injectors, each'having a passage connected at its respective ends to said supply and return orifice extending from said injector passage and communicating with a cylinder, and a restrictive orifice in said injector passage between said metering orifice and said return line and cooperating with said pump and said pressure regulator to establish a predetermined pressure in the fuel at said metering orifice, said valve member being adapted, when .the engine exceeds a predetermined speed, to stopfiow from the pump whereby said enlarged opening in the pressure regulator is opened to dump the flow from thepump, and being adapted to connect said delivery passage and said drain passage to relieve the pressure of. the fuel at the metering orifices to prevent flow therethrough.

5. A fuel supply apparatus for a multi-cylinder internal combustion engine, comprising means for supplying fuel under pressure, a governor-operated valve connected to receive-fuel from said means and having a delivery passage, a drain passage, and a movable valve member for controlling the how of fuel to said passages, and a plurality of injectors, each having a passage cona supply line connected to said lines, a metering necte'd at-one end :to rece've fuel from :said adelivery passage and at the other end to drain, :a metering :orifice extending from ,said iinjector passage and communicating with a cylinder 'for metering fuel to :be injected :into "the cylinder, and a restrictive orifice in :said injector passage between said meterin'g orifice and 'said :other end of the passage and =cooperating with :said means to establish 'a. predetermined pressurein the fuel at said metering orifice. said valve member being adapted, when :the engine 'exceeds a predetermined maximum speed, to shut off the flow of fuel from said means to said valve and to connect said delivery and drain .passage to relieve the pressure of the fuel at the metering orifices to prevent flow therethrough.

6. A fuel supply apparatus for a multi-cylinder '.in-

ternal combustion engine, comprising a fuel tank, a :supply dinit comprising a housing, means associated with said housing and connected to said tank for supplying fuel under pressure, and a governor-operated 'valve mounted in said housing :and connected to said means to receive fuel therefrom, said valve having a delivery passage, a drain passage opening into the interior of the housing, and a movable valve member for control- *Iing the flow of fuel to said passages, a :suppl-y'line connected to said delivery passage, :21 return line connected i to said tank, and a plurality of injectors, each having a passage connected at its respective :ends to said supply and return lines, said valve meniber'being adapted, when the engine exceeds :a predetermined maximum speed, to shut off the flow from .said means and to connect :said defiv'ery and-drain passages to drain fuel 'from said supply line and the injector passages into the housing, said hous- 'inghaving an overflow connection :with said return line *to return the overflow to said tank.

'7. An injector for injecting fuel into :the cylinder of an internal combustion-engine, comprising :an injector body hai/ ing a passage extending ltherethrough and adapted to be connected at its respective ends :to fuel supply and return lines for the circulation .of fuel through said passage, said body 'also having a chamber having an opening for communication with a cylinder and 'a metering vorifice extending from said passage to said chamber for metering dual to be injected into associated cylinder and means for injecting *fuel from said chamber through said opening, said passage having a restrictive orifice between said meterin'g orifice and the end of the passage adapted to be connected to the return line to establish a predetermined pressure in the fuel in said passage at said metering :orifice.

8. An injector for injecting fuel into the cylinder for '-an'-i mernal combustion comprising an injector body-including a nozzle :and having a passage adapted to be 'connected at its respective end-s40 fuel :supply and return line's a portion of the passage located adjacent sziiall nozzle, saidbody also having a chamber communicit'ing with said- ;n'oz'zle and 'a'metefing orifice extending tronisuid portion to 'said cham'berfor metering fuel to said nozzle, and means for forcing 'fuel from said chamher: through said nozzle, said passage having a restrictive orifice between said portion and the end of the passage ,ladap'tcd to be. connected to the .re'turn .line to establish a predetermin ed pressure .in the fuel in said portion.

9v. injector for injecting fuel into the cylinder of intennal mmbustion engine, comprising an injector :bodyincluding :a nozzle and having a plunger bore extending to :said :nozzle and :having a plunger mounted in said bore, said body having a passage haningone end adapted to be connected to a supply line and the other endmdapted to be connected to a return line and an intermediate portion- 'located adjacent nozzle, said :body

also-haulage imeteringionifice extending :from said inter- ,anedinte portion to said plunger ibore :for .metering'rfuel to maid nozzle, said passage having a restrictive orifice intermediate portion :and said other end 18 to establish a predetermined pressure in the fuel in said intermediate :portion.

10. An injector for injecting fuel into a cylinder :of an internal combustion engine, comprising an elongated body having a nozzle at one end, said body having a longitudinal plunger bore extending to said nozzle and a plunger reciprocably mounted in said bore for injecting fuel from said bore through said nozzle, said body also having a supply passage adapted to receive fuel from a supply line, a return passage adapted to discharge fuel to a return line, an intermediate passage located adjacent said nozzle and connecting said supply and return passages to permit circulation of fuel therethrough, and a metering orifice extending from said intermediate passage -to said plunger bore for metering fuel from said intermediate passage into said bore, said return passage having a restrictive orifice to establish a predetermined pressure in the fuel in said intermediate passage.

11. An injector for injecting fuel into the cylinder of an internal combustion engine, comprising an injector body including a nozzle and having a plunger bore with one end extending to said nozzle and a plunger reciprocably mounted in said bore for injecting fuel :fromzsaid bore through said nozzle, said body having a supply passage adapted to be connected to a supply line, 'a return passage adapted to be connected to a return line, an intermediate chamber located adjacent said nozzle and connecting said supply and return passages to permit circulation of fuel therethrough, and a metering orifice extending from said intermediate chamber to said plunger bore for metering fuel into said bore and adapted to be opened and closed by movement of said plunger, one'of said passages including va portion of said bore as a part thereof with said portion adapted to be opened and closed by movement of said plunger.

12. An injector for injecting fuel into the cylinder of an internal combustion engine, comprising an injector body including a nozzle and having a plunger bore one end extending to said nozzle and a plunger reciprocably mounted in said bore for injecting fuel from said bore through said nozzle, said body having a supply passage adapted to the connected to a supply line, a return passage adapted to be connected to a return line, an intermediate chamber located adjacent said nozzle and connecting said supply and return passages to permit circulation of fuel therethrough, and a metering orifice extending from said intermediate chamber to said plunger bore for .rnetering fuel into said bore .and adapted to be opened :and closed by movement of said plunger, one of said passages comprising two separated portions both opening into :sajdbore and-connected thereby with one of said portions adapted to 'be opened and closed by movement of said plunger.

' '13. An injector for injecting fuel into the cylinder of an internal combustion engine, comprising an injector flnody'zincluding a nozzle and having a plunger :bore with one end extending to said nozzle and a plunger reciprocably mounted in said bore for injecting fuel from said bore through said nozzle, said body having a supply passage adapted to vbe connected to a supply line, a return passage adapted to be connected toaa return line, an intermediate chamber located adjacent said nozzle and com :necting said supply and return passages to permit tionaof fuel therethrough, and a metering orifice extending 65 from said intermediate chamber to said plunger bore for metering fuel into said here and adapted "to be opened and closed by movement of said plunger, one of said passages :having a portion adapted to be opened and closed as an incident to movement of said plunger.

14. An injector for injecting fuel into the cylinder :of an internal combustion engine, comprising an injector body :including a nozzle and having .a plunger ebore -with one end extending to said nozzle and a plunger reciprocably-mounted in said bore for injecting fuel rfroin said 75 bore through said nozzle, said body having a supply passage adapted to be connected to a supply line, a return passage adapted to be connected to a return line, an intermediate chamber located adjacent said nozzle and connecting said supply and return passages to permit circulation of fuel therethrough, and a metering orifice extending from said intermediate chamber to said plunger bore for metering fuel into said bore and adapted to be opened and closed by movement of said plunger, said plunger having a portion associated with one of said passages andadapted to close said one passage to prevent flow through the injector body when said metering orifice is closed.

15. An injector for injecting fuel into the cylinder of an internal combustion engine, comprising an injector body including a nozzle and having a plunger bore with one end extending to said nozzle and a plunger reciprocably mounted in said bore for injecting fuel from said bore throughsaid nozzle, said body having a supply passage adapted to be connected to a supply line, a return passage adapted to be connected to a return line, an intermediate chamber located adjacent said nozzle and connecting said supply and return passages to permit circulation of fuel therethrough, and a metering orifice extending from said intermediate chamber to said plunger bore for metering fuel into said bore and adapted to be opened and closed by movement of said plunger, said plunger having a portion associated with one of said passages to open and close the latter, said portion being adapted to open said one passage before said metering orifice is opened to permit the flow of fuel to purge said passages of air before the metering orifice is opened.

16. An injector for injecting fuel into the cylinder of an internal combustion engine, comprising an injector body including a nozzle and having a plunger bore with one end extending to said nozzle and a plunger reciprocably mounted in said bore for injecting fuel from said bore through said nozzle, said body having a supply passage adapted to be connected to a supply line, a return passage adapted to be connected to a return line, an intermediate passage located adjacent said nozzle and connecting said supply and return passages to permit circulation of fuel therethrough, and a metering orifice extending from said intermediate passage laterally into said bore adjacent said end thereof so that it is closed by the plunger when the latter moves toward said end and is open for metering fuel into said bore when the plunger moves away from said end, said return passage having two separated portions both opening laterally into said bore intermediate the ends thereof and said plunger having a reduced portion extending between said separated portions to permit flow therebetween through said bore, one end of said reduced portion being adapted to move across one of said separated portions to open and close the latter to prevent flow through said passages when the metering orifice is closed;

17. An injector for injecting fuel into a cylinder of an internal combustion engine, comprising an injector body including a nozzle and a fuel chamber'adjacent the nozzle, said body having a supply passage adapted to be connected to a fuel supply line, a return passage to be connected to fuel return line, an intermediate passage connecting said supply and return passages, and a metering orifice connecting said intermediate passage with said chamber, and a plunger reciprocably mounted in said injector body and having an end portion movable into said chamber for injecting fuel therefrom and movable across said metering orifice to open and close the latter, and another portion associated with said return passage for opening and closing the latter to prevent flow through said passages when said metering orifice is closed.

18. An injector forinjecting fuel into a cylinder of an internal combustion engine, comprising an injector body including a nozzle and a fuel chamber adjacent the nozzle, said body having a supply passage adapted to adapted vline, an intermediate pass plunger bore and connected thereby,

tions by movement of said plunger.

:20 be connected to a fuel supply line, to be connected to fuel return line, an intermediate passage connecting'said supply and'retur'n passages, and a metering orifice connecting said-intermediate passage with said chamber, and a plunger reciprocably mounted in said injector bodyand having an end portionmovable into said chamber for injecting fuel therefrom and movable across said. metering orifice to open and close the latter, and another portion associated with said return passage for opening and closing the latter to prevent flow through said passages when said metering orifice is closed, said return passage having a restrictive orifice to establish a predetermined pressure in the fuel in said intermediate passage when said return passage is open. a

19. An injector for injecting fuel into a cylinder of an internal combustion engine, comprising an injector body including a nozzle and a fuel chamber adjacent the nozzle, said body having a; supplypassageadapted to be connected to a fuel supply line, a return. passage adapted to be connected to fuel return line, an intermediate passage connecting said supply and return passages, and a metering orifice connecting said intermediate passage with said chamber, and a plunger reciprocably mounted in said injector body and having an end portion movable into said chamber for injecting fuel therefrom and movable across said metering orifice to open and close the latter, and another portion associated with said return passage for opening and closing the latter to prevent flow through said passages when said metering orifice is closed, said other portion of the plunger being adapted to open said return passage prior to the opening of .said metering orifice to permit flow of fuel through saidpassages to purge them of air before said meteringorificeis opened, said return passage having a restrictive orifice therein to establish a predetermined pressure in the fuel flowing through said intermediate passage. 7

20. An injector for injecting fuel into a cylinder of an internal combustion engine,,comprising an injector body including a nozzle and having a plunger bore with one end extending to said nozzle and a plunger reciprocably mounted in said bore for injecting fuel from'said end of the bore through said nozzle, said body having a fuel passage adapted at its respective ends to be connected to a supply line and a return line and extending adjacent a return passage adapted said nozzle, and a metering orifice extending from said fuel passage to said plunger bore, said fuel passage between said supply line and said metering orifice including a portion of said plunger bore as a part thereof with said portion adapted to ,be opened and closed by movement of said plunger. f v

21. Anlinjector for injecting fuel into a cylinder of an internal combustion engine, comprising an injector body including a nozzle and having a plunger bore with one end extending to said nozzle and a plunger reciprocably mounted in said bore for injecting fuel from said end of the bore through said nozzle, said body having a supply passage adapted to be connected toja supply line, a return passage adapted to be connected to a return age located adjacent said nozzle, and a metering orifice extending from said intermediate passage to said'plunger bore and adapted to be opened and closed by'movement of said plunger, said supply line comprising two separated portions both opening into said said plungerhaving a reduced portion to permit flow of fuel between said two portions, and said'reduced portion providing a shoulder adapted to open and close one of said .two por- 22. An injector for injecting fuel into a cylinder of an internal combustion engine, comprising "an-injector body including a nozzle and having a plunger borewith one end extending to said nozzle and a plunger reciprocably mounted in said bore for injecting fuel from said end of the bore through said nozzle, said body having a supply passage adapted to be connected to -a-supply- 'line,

a return passage adapted to be connected to a return line, an intermediate passage located adjacent said nozzle, and a metering orifice extending from said intermediate passage to said plunger bore and adapted to be opened and closed by movement of said plunger, said supply line including a portion of said plunger bore as a part thereof with said portion adapted to be opened and closed by movement of said plunger, and said return line having a restrictive orifice to establish a predetermined pressure in the fuel in said intermediate passage.

References Cited in the file of this patent UNITED STATES PATENTS Fisher Jan. 1, 1918 Fisher Mar. 16, 1920 Widdowson Jan. 4, 1927 Riegels Dec. 14, 1937 Nichols Oct. 21, 1952 FOREIGN PATENTS France Oct. 11, 1932 Switzerland Nov. 16, 1939 Great Britain July 6, 1950