US2326171A - Fuel injection device - Google Patents

Description

Aug. 10, 1943. REGGIO 2,326,171

FUEL INJECTION DEVICE Filed Aug. 17, 1940 3 Sheets-Sheet 1 w /--1o 4 5 I96 2 Q?" M Q o Q '20 Q us 4 I Q 4 ||z Q I22 at? l 4 as Aw -|sz I INVENTOR i m 4 F C Filed Aug. 17, 1940 3 Sheets-Sheet 2 INVENTOR 1943. F. c. REGGIO 2,326,171

FUEL INJECTION DEVICE Filed Aug. 17, 1940 3 Sheets-Sheet 3 23o I 236 Q] V A I fi- W zm F l LI 2 J INVENTOR F. C.

Patented Au 10, 1943 UNITED STATES PATENT OFFICE 2,326,171 FUEL INJECTION DEVICE Ferdinando Carlo Reggio, Detroit, Mich. Application August 17, 1940, Serial No. 353,002

16 Claims. (Cl. 123-139) This invention relates to a fuel supply system for internal combustion engines, and in particular to a fuel injection system for delivering liquid fuel under pressure and in measured quantities into the cylinders or into the induction manifold of the engine. More specifically the invention relates to an injector system including a governor having a hydraulic operating connection with the fuel metering pumps. In so far as the subject matter is common this invention is a continuation in part of my applications Ser. No. 236,249 filed October 21, 1938, Ser. No. 254,355 filed February 3, 1939, Ser. No. 333,529 filed May 6, 1940, and Ser. No. 346,479 filed July 20, 1940.

An object of the invention is to provide an improved arrangement of fuel system including a fuel injector, a governor, and hydraulic means for connecting the governor with the injector. Another object is to provide an. injector which may be readily removed from the engine and replaced thereon. Still another object is to provide an injector which may be quickly and easily connected with and disconnected from one or more fuel lines or conduits. A still further ob ject is to provide common means for clamping the injector on the engine, and simultaneously effecting the connection of one or more pipes or conduits therewith. Still another object is" to provide an engine fuel injector, or injection pump unit, which may be hydraulically controlled, or

vented or liquid cooled, so arranged that it may be quickly and easily mounted on the engine, and connected with one or more pipes or conduit containing liquid fuel or other-appropriate fluid such for example as lubricating oil, or other suitable liquid coolant. Another object is to provide a simple and compact governor which is relatively inexpensive to manufacture and accurate in operation. A still further object is to provide improved safety devices for stopping the fuel supply of the engine under predetermined operating conditions.

The above and other objects of the invention will be apparent as the description proceeds; and while I have illustrated and described the preferred embodiments of the invention as they now appear to me, it will be understood that such changes may be made as fall within the scope of the appended claims. In the following description and in the claims various details will be identified by specific names for convenience but they are intended to be as generic in the application as the art will permit.

The drawings show various embodiments of my invention: Figure 1 is a transverse section showing the injector of my invention and the governor for controlling the delivery of the injector. Figure 2 is a transverse elevational view of the injector of Figure 1 showing a detail of the fuel connections thereof. Figure 3 is in part a front view of the injector of Figures 1 and 2 and in part a section taken along the line 3--3 of Figure 1. Figure 4 is a partial modification of the governor shown in Figure 1. Figure 5 shows part in view and part in section safety devices for stopping the engine fuel supply. Figures 6 and I 7 show a modified form of injector.

is adapted to be reciprocated from an enginedriven cam M by a tappet mechanism IS. The plunger may be of any suitable construction, preferably of the type in which the quantity of fuel injected by the pump is controlled by an angular adjustment, or rotation of the plunger about its axis. Such type of construction is well-known and therefore it is regarded unnecessary to show and describe it in greater detail. Plunger I2 is slidably but non-rotatably mounted in pinion 18 which pinion is mounted with suitable axial and radial clearance in housing 6 and engages a rack 20 reciprocable in a bore of housing 6, so that an axial movement of the rack causes rotation of plunger I2 and in turn a variation of the delivery of the injector. A spacer 22 having a central fuel passage is clamped on the inner end of barrel 8. The housing 6 of the injector is provided with a passage 24 formed preferably at right angles with the axis of plunger [2 and in which is mounted a fuel conduit member 26 held in proper angular position by means of a dowel and slot connection 28. The outer end of conduit member 26 is seated aaginst the end of the wall of passage 24, while the inner end thereof is provided with a head 30 adapted to be clamped against spacer 22. A check or non-return valve, not shown in the drawings, is inserted in a, suitable cavity between head 30 and spacer 22. The central or intermediate portion of conduit member 26 is formed with a reduced section so as to be resilient and adapted to yield within designed limits.

Against the outer end of conduit member 28 there is mounted a nozzle tip member 32 clamped by means of a cap 34 screwed onto the wall of passage 24. A spring-loaded non-return fuel valve, also not shown in the drawings, is provided between the fuel conduit member 26 and the nozzle tip member 32; and a duct axially formed in the latter leads fuel to the discharge orifice 36 drilled at the 'end of nozzle tip member 32. The head 38 at the inner end of the fuel conduit member 26 and the spacer 22 are clamped against the barrel 8 by means of a spacer 38 which in turn is clamped by a screw plug 48. An annular seal 42 interposed between spacer 38 and screw plug 48 prevents leakage of fuel therepast. Thus all the parts of the injector may be very easily assembled or taken apart. In assembling, rack 28 is mounted in its bore; pinion I8, plunger l2, barrel 8, and spacer 22 may be introduced from the top of housing 6; then the conduit member 26 is mounted endwise through passage 24 and clamped therein by means of nozzle tip member 32 and cap 34, then the head 38 is clamped against spacer 22 by means of upper spacer 38 and screw plug 48. Since the intermediate portion of conduit member 26 has a comparatively reduced cross section, this portion will yield as it may be necessary to insure a uniformly distributed contactvpressure between said head 38 and spacer 22 when screw plug 48 is tightened, thereby eliminating the danger of fuel leakage therebetween and distortion of the pump barrel 8.

The plunger I2 is formed with a head 44 and a groove 46 adjacent the outer end thereof adapted to provide a head and T-slot detachable connection with the upper portion 41 of tappet mechanism I6. Fuel enters the injector through an inlet 48 communicating by means of a duct 49 having its outer end closed by a plug 58 with the groove axially machined in the barrel 8 and in the lower spacer 22, which groove establishes a fuel communication between the barrel port l8 and the passage 24. Excess fuel flows into passage 24 and leaves the injector through a duct 52 and an outlet 53. This fiow of fuel, determined by a fuel transfer pump, vents the injector of all bubbles of air, vapor, or gas that may separate from the fuel and which might otherwise reach the pressure chamber of the plunger I2 through port I8 and interfere with the correct operation of the pump. Such fiow of fuel also cools the various parts of the injector.

The rack 28, which controls the fuel delivery of the injector 6, is formed as a plunger slidable in a bore'formed in housing 6. One end of rack 28 extends into a chamber 54 closed by a plug 56, to which chamber fuel is led from the inlet port 48 through a duct 58. A calibrated coil spring 68 is mounted between the opposite end of rack 28 and a cap 62 having a threaded connection with injector housing 6. A rod 64 of small diameter fixedly connected with rack 28 and coaxial therewith extends through a central opening of cap 62 and can be manually operated to temporarily modify the axial adjustment of rack 28. I

The adjustment of rack 28 and in turn the fuel discharge of the injector are dependent on the value of the fuel pressure in the inlet port 48. An increase in fuel pressure causes a movement of rack 28 until the increased hydraulic load on the latter is balanced by a correspondingly increased resilient load of spring 68. The preferred arrangement is such that a displacement of rack 28 toward the left, as shown in Figure 3, determined by an increase in fuel pressure in inlet port 48 causes an increase of fuel delivery of the pump. The pressure of the fuel led to injector 6, and the fuel discharge thereof will therefore simultaneously increase or decrease according to a predetermined relationship; The maximum displacement of rack 28 toward the left is determined by cap 62; the maximum fuel discharge per stroke of the injector may therefore be set at a predetermined value by adjusting the thickness of gasket 66 interposed between cap 62 and housing 6. Furthermore, the spring 68 has a definite rate of deflection and its load is initially determined by adjusting the thickness of spacer 68 mounted at one end thereof so that with a given pressure at the inlet port 48 the pump 6 discharges a determined amount of fuel per plunger stroke. Pumps 6 are therefore interchangeable. Obviously, while in the example above disclosed the variable fuel pressure acts directly on rack 28, other pressure-responsive devices such as a piston, or flexible diaphragm or bellows may be provided for actuating the rack 28 or other injector fuel delivery control member.

Control of the engine fuel supply may thus be obtained by governing the pressure of the fuel led to the various injectors 6 thereof. Figures 1 t 3 of the drawings show the injector 6 applied to an internal combustion engine, either of the compression-ignition or of the spark ignition type, having a cylinder block I8 and a cylinder head I2 clamped thereon with a gasket I4 interposed therebetween, and adapted to discharge fuel into the chamber 16 formed in the cylinder head I2.

It is important that the injector be firmly attached to the engine and held in accurately determined position relative to the tappet or reciprocating mechanism I 6. To that end the injector 6 is provided with a flange 88 the lower surface of which is normal to the axis of plunger l2 and is adapted to be clamped on the upper surface of the cylinder block I8 or other suitable machined surface thereof. In the upper wall of the cylinder block I8 an opening is provided, through which the lower part of the injector 6 extends into the tappet compartment.

A fuel line element 82 has at one end an expanded head 84 adapted to be clamped on the tapered wall of fuel inlet 48 of the injector by means of the retaining member 86, and at the opposite end an expanded head 88 against which one extension 98 of the fuel inlet manifold 92 is clamped by meansof a threaded cap 94 thereby establishing a detachable fuel connection between inlet manifold 82 and inlet port 48 of injector 6. A fuel line element 96, similar to line element 82, forms a detachable fuel connection between the return outlet port 53 of the injector and the fuel return manifold 98.

The retaining member 86 is supported at one end against the edge of a cavity I88 formed in the cylinder block I8, while at the other end it is clamped by means of a stud I82 secured to the engine head I2 and a nut I84, thus exerting on the head 84 of fuel line element 82 and on the similar head of fuel line element 86 loads sufficient to prevent any fuel leakage. The arrangement of the retaining member 86 and its attachment are such that the resultantof such loads transmitted to the injector 8 passes through or near the point of intersection of the axis of plunger l2 and nozzle 32 thereof, and forms a suitable angle, shown as 45 degrees in the drawings, with said axes, whereby said resultant is resolved into two component loads, one having substantially the direction of plunger I2 and serving to clamp the injector on the engine block against the thrust transmitted to the plunger by tappet I6; and the other having substantially the direction of the axis of nozzle part 32 of the injector and serving to clamp the latter and the gasket I06 thereof, or equivalent sealing means, against a suitable shoulder provided in the engine head 12.

Sufficient radial clearance is provided between the horizontally extending nozzle part 32 and cap 34 of the injector and the cavity of the cylinder head 12 in which saidnozzle part and cap are mounted so as to avoid any binding when the injector is clamped into position, regardless of the changes in the thickness of gasket 14 interposed between the engine block 10 and the cylinder head 12. By this arrangement the danger of bending the housing of injector 6 and asymetrically deforming the barrel 8 thereof is eliminated.

A camshaft I4 is supported in bearings carried by the engine block 10 and serves to actuate through push rods IIO the inlet and exhaust valves, not shownin the drawings, mounted in the head 12 of the engine. Any suitable tappet mechanism for actuating the plunger I2 of injector 6 from said camshaft may be provided. A convenient arrangement, shown in Figure 1,

includes a cam follower of the mushroom type II2 reciprocably mounted in a guide II4 carried by the engine block 10 and provided with a cavity therein containing a retainer II6 urged against the spherical inner end of said cavity by the lower end of the coil spring H8, the upper end of which is held by cap I having a threaded connection with guide I I4. The tappet rod I6 is provided at its lower end with an expanded head I22 held with small clearance between the end of said cavity and retainer H6, while at its upper end it carries a connecting member 41 having a permanent press fit in rod I6. Such connecting member 41 includes a head formed with a T-slot having a close fit with the head 44 formed at the lower end of pump plunger I2. A U-shaped retaining member I24 slidably mounted about the connecting member 41 is upwardly urged by a spring I26 to laterally close the T-shaped slot and eliminate the danger that the head 44 of plunger l2 may be accidently disconnected from the connecting member 41. Said retaining member I24 is shown in its operating position in the drawings, but it may be displaced against the load of spring I26 to a position in which the tappet rod I6 may be disconnected from the pump plunger I2.

It is therefore clear that tappet rod I6 is centered at its lower and upper ends by the cam follower I I2 and by the pump plunger I2 respectively, thus eliminating the necessity of providing guiding or supporting means therefor, and furthermore, it may be readily detached from the pump plunger I2. Thus, spring II8 holding the cam follower H2 in contact at all times with the cooperating cam carried by camshaft I4 also effects the return or suction stroke of pump plunger I2 of injector 6.

In the preferred embodiment of the invention the cam follower H2 and the tappet rod I6 are coaxial or substantially coaxial with the pump plunger I2 of the injector 6; hence slight changes in the position of injector 6, such as might be caused by changes in the thickness of nozzle gasket I06, do not cause any appreciable modification in the adjustment of pump plunger I2 and therefore do not affect the tim- 1118 of the injection. Furthermore, it is to be noted that, although the injection is effected through the walls of cylinder head 12 into the chamber 16, the distance of the injector 6 from the camshaft I4 is determined by the distance between the latter and the machined upper surface of the cylinder block 10 and is therefore independent of changes in the thickness of the cylinder head gasket 14. According to the preferred embodiment of the invention the distance between the camshaft I4 and the upper machined surface of the cylinder block 10 on which the injector 6 is clamped, the radii of the cam and the length of the tappet mechanism between cam and plunger I2 are all accurately kept within close predetermined tolerances: the result being that when the camshaft I4 is in a given angular adjustment, forexample corresponding to-the point of minimum lift of the tappet mechanism, the T-shaped slot of the connecting member 41 thereof and in turn the head 44 of the pump plunger I2 are within a close predetermined tolerance at a definite distance from the machined surface of flange 80. Preferably, the various elementary parts included in the tappet mechanism are machined within strict tolerances so that they may be individually replaced without affecting the total length thereof. Furthermore, in injector 6, when the head 44 of pump plunger I2 is at a definite distance from the lower surface of flange 80, that portion of plunger I2 which is adapted to cover and uncover the inlet port I0 of barrel 8, and thus controls the injection, is atcorrespondingly predetermined distance from said port I0, whereby all injectors 6 are interchangeable. Thus the injectors as well as the various parts of the tappet mechanism and the cylinder head gasket 14 may be replaced without requiring adjustment of the injection timing.

It may be shown that slight variations in the lengths of the various parts of the tappet mechanism and of the injector within reasonable manufacturing tolerances cause variations in the injection timing that usually are considerably smaller than one degree of crank shaft rotation. Injection timing is therefore far more accurate than with the conventional injection system including separate injection nozzle and fuel pump interconnected by a comparatively long highpressure fuel line wherein pressure surges and fuel compressibility adversely affect the injection characteristic and the accuracy of the timing thereof.

The tappet mechanism compartment in the cylinder block 10 is enclosed by a cover I30, and the injector compartment in the cylinder head 12 is enclosed by another cover I32.

In order to inspect the operation of the injectors 6 in a multicylinder engine it is suflicient to remove the cover I30 and, while the engine is operating, push successively the rods 64 extending from the various injectors thereby temporarily shutting off the fuel delivery thereof. It may thus be promptly ascertained whether all the injectors 6 are operating correctly. In order to replace one of the injectors, the retaining member I24 of the tappet rod is -m0ved downward against spring I26, and tappet rod I6 is disconnected from plunger I2. Then the cover I32 is removed, the threaded caps 94 are untightened to loosen the fuel line elements 82 and 96, and the nut I04 is unscrewed to permit removal of retaining member 86. Fuel line elemerit? and 96 are moved sidewise away from the injector 6 and the latter may be withdrawn with a translation at first horizontal in order to clear the nozzle tip 32, then vertical so that the lower expanded portion of the indector may pass through a suitable opening provided in the upper wall of cylinder block 16; whereupon the injector 6 may be removed' from the cylinder head 12. The same operations in inverted order are necessary for a sembling the injector on the engine.

The fuel manifolds 92 and 98 are attached to cylinder block I6 and need not be removed when the cylinder head I2 is disassembled. From the foregoing it will be appreciated that the injectors 6 may be readily and easily inspected and replaced, which is important not only in manufacturing but also in servicing in thefleld. It has been stated in the foregoing that the fuel supply of the engine is controlled by adjusting the pressure of the fuel led to the injectors 6.:

To that end a fuel transfer pump I36 shown as a pump of the gear type mounted in a housing I38 attached to a wall of thecylinder block I6 includes a gear I46 driven from the engine camshaft I4 and meshing with an idler gear I44. The pump I36 draws fuel through supply lines I46 and I48 and discharges it under pressure into lines I56 and I52 and inlet manifold 92. In a multi-cylinder engine having several injectors 6, the latter are connected in parallel between fuel inlet manifold 92 and fuel return manifold 98. The fuel discharge of the transfer pump I 36 is thus equally divided among the injectors, and the excess of said discharge, that is the amount of fuel which is not injected into the engine cylinders, serves to vent and cool the injectors, and is thereafter led through line I54 to a duct I56 communicating with a bore formed in valve body I58, in which bore is slidably and rotatably mounted a pressure regulating valve of the plunger type I66.

A speed governor includes a shaft I62 rotatable in a sleeve I64 and driven from camshaft I4 of the engine or other suitable shaft thereof. Shaft I62 coaxial with valve "I66 carries fiyballs I66 having inwardly extending arms which engage the lower end of valve I66, while the upper end of said valve carries the inner race of a ballbearing I68. A governor spring I I6 is mounted between the outer race of bearing I68 and seat I12 slidably mounted on a guide pin I'l4 carried by cover I16. A floating lever I 86 is connected at one end with lever I82 carried by a shaft to which the throttle lever I 84 is secured, at the other end with the plunger I86 slidably mounted in a bore formed in body I56, and at intermediate point with seat "2 of governor spring "6.

An annular groove I96 machined in the intermediate portion of valve I66 is in permanent communication with duct I56, while it communicates with groove I92 connected with line I48 through an annular opening whose area is dependent on the axial adjustment of valve I66. Plunger I86 is urged upwardly by the pressure of fuel in line I56 applied to its lower end, while the upper end thereof is loaded by a spring I94 wound about threaded screw I96 adjustably mounted in cap I98 and provided with a. lock nut. The upper coil of spring I94 extends radially into a groove or opening provided in cap I98 so as to prevent angular rotation of the spring relative to the cap, the result being that the number of free or active coils of spring I94, and in turn its rate of deflection, may be varied by rotating the screw I96 relative to cap I98. Furmg increase of pressure in the fuel lines.

thermore cap I96 has a threaded connection with cover I16 and is also provided with a locking nut.

When the engine is inoperative the pressure in all fuel lines is the same as in thesupply lines I46 and I46. The inJectors 6 are adjustedfor no delivery. The valve I66 is in its lower position and closes the communication between grooves I96 and I92. The plunger I66 is also in its lower position. Assuming the engine. to, be cranked, the fuel transfer pump I36 draws fuel from the supply line I46 and discharges it through lines I56 and I52 into the fuel inlet manifold 92. The fuel pressure rises rapidly and reaches its maximum value, which may be regulated byadjusting cap I98 relatively to cover "6, whereupon plunger I66 opens the by-pass 266 and prevents a further increase in pressure. Fuel is thus circulated through injectors 6, which helps remove all gas or vapor bubbles therefrom. Accordingly, the injectors 6 are adjusted for maximum fuel delivery and, actuated by tappet mechanism I6, inject fuel into the engine cylinders. As firing occurs in the latter and the engine speed increases and approaches the value corresponding to the setting of the throttle lever I84, valve I66 is lifted by the fiyballs and establishes a fuel communication between grooves I96 and I92.

Since the capacity of the fuel transfer pump I36 is in excess of the total maximum discharge of injectors 6, when the engine is operating under the control of the governor, that is when the duct 266 is closed by plunger I86, the excess fuel is by-passed through the open area of the annular opening between grooves I96 and I92 controlled by valve I66. A downward displacement of the latter causes a reduction of area of said opening and therefore an increase in speed of the fuel flowing therethrough and a correspond- Conversely, an upward displacement of valve I66 causes an increase of said area, a reduction of speed of the fuel by-passed therethrough and a corresponding decrease of pressure in the fuel manifold. The adjustment of valve I66 relative to groove I 92 is dependent on the simultaneous actions of the load of spring I16 and of the centrifugal force transmitted by fiyballs I66. It is therefore dependent on the adjustment of the throttle lever I84, on the engine speed and on the adjustment of plunger I86.

Any governor of conventional character (with the exception of isochronous type) in order to be stable must regulate the speed of its engine in such a manner that the speed is lower for full load than for no load. If the difference between maximum and minimum speed divided by the average speed, or speed' droop" is high the speed regulation is soft and the change from a given amount of engine fuel supply to another caused by a change of load on the engine is not abrupt but gradual. A smaller speed droop causes a more abrupt speed regulation because small speed variations involve large changes in the engine fuel supply. When the engine is operating under steady load the valve I66 is in stable equilibrium; if the engine load increases the engine speed decreases and the centrifugal force acting on fiyballs I66 also decreases causing a downward movement of ,valve I66 and an increase of fuel pressure in the upwardly against the load of spring I94 thus raising the left end 01' floating lever I80 and the seat I12 of spring I10. The load of the governor spring I being reduced, the equilibrium of the governor will be re-established at an engine speed corresponding to that value of the centrifugal force of flybalis I 66 that balance the new load of spring I10. The engine speed under the heavier engine load will therefore be lower than the engine speed under lighter engine load.

Conversely, when a drop in engine load occurs the engine accelerates and the fiyballs I66 lift the valve I60 causing a reduction of fuel pressure in the fuel manifolds. The fuel discharge of in- Jectors 6 decreases causing a diminution of engine speed and determining a downward displacement of plunger I86 which in turn increases the load of governor spring I10. The decrease in engine load will therefore cause an increase of engine speed. The condition of stability of the governor, that is the ability to cause the engine speed to decrease when the engine load increases, is thus satisfied. The desired nominal engine speed is set by means of throttle lever I84, which may be adjusted by the operator or by automatic devices. Anti-clockwise rotation of lever I84 increases the load of spring I10 and in turn the engine speed; A stop may be provided to limit the anti-clockwise rotation of lever I84 thereby determining the maximum engine speed, while anadjustable resilient stop may limit the clockwise rotation of the lever to set the engine idling speed. Neither of the stops are shown in the drawings. Clockwise rotation of lever I84 beyond its position determined by the resilient stop causes valve I60 .to substantially increas the area of passage between grooves I90 and I92 thereby stopping the engine.

Figure 4 shows a partially modified governor in which the speed droop is adjusted not by varying the number of active coils of spring I94 thereby changing the deflection rate thereof, but by controlling the rate of pressure change in compensating chamber 2| 0 at the lower end of plunger I86, which chamber communicates with fuel lines I48 and I56 through orifices whose open areas may be adjusted by means of needle valves 2I2 and 2I4 respectively. If the orifice controlled by valve 2I4 is closed While the orifice controlled by valve 2I2 is open, the fuel pressure in chamber 2I0 is the same as in fuel supply line I46, the engine speed droop has its minimum value, substantially zero, and the governor is likely to be unstable. If needle valve 2I2 is closed and needle valve 2I4 is open the speed droop has its maximum designed value.

Obviously, when both needle valve 2I2 and 2I4 are open the fuel pressure in valve 2I0 has a value comprised between the pressures in lines I56 and I48. Assuming that the pressure in the latter is equal to the surrounding atmospheric pressure, the effective pressure p in the compensating chamber 2I0 is (5.) where 211 is the effective pressure in line I56, and a1 and as are the open areas of the orifices controlled by needle valves 2I4 and 2 I2 respectively. That is, the ratio between the fuel pressures in chamber 2I0 and in line I56 may be varied between one and zero by properly adjusting the needle valves 2 I 2 and 2I4. The speed droop varies substantially in proportion with said ratio.

Any determined value of speed droop within the designed limits of the governor corresponds to a definite ratio between the open areas controlled by needle valves 2I2 and 2I4. Yet the open area of one or the other of said orifices may be arbitrarily chosen so as to obtain a suitable dampening eIiect,-or dash pot" action, on plung er I86.

The only friction that the governor has to overcome is that opposing the axial displacements of plunger I86 and valve I60. Since the latter rotates together with fiyballs I66 the friction opposing its axial movement has a very low value. Friction opposing the axial displacement of racks 20 of the injectors 6 does not influence the operation of the governor. If one of the pump plungers I2 should stick in its barrel and remain stationary at the end of its discharge stroke with the load of spring II8 insufficient to bring it back, the pump would stop delivering fuel to its cylinder but it would not interfere with the control of the remaining injectors, while with the conventional mechanical linkage interconnecting all the racks 20 the damaged injector might prevent the regulation of the other injectors thereby putting the engine out of control.

The effect of the frictional resistance opposing the axial movement of the racks 20 is reduced or eliminated by the pressure surges caused by the rapid opening and closing of ports I0 and transmitted to the chambers 54 through conduit 58. Owing to said surges the hydraulic load applied to the racks 20 has a pulsating character. The range of said high-frequency pulsation of the load applied to the racks may be reduced, if it should appear desirable, by reducing the section of conduit 56 or otherwise increasing the resistance to the flow of fuel therethrough.

Non-adjustable orifices may obviously be substituted for one or both of the needle valves 2I2 and 2I4. The fuel manifolds 92 and 88, and the conduits connecting the latter with duct I56 of the governor are of such large sections that under all operating conditions the fuel pressure in the injectors and in duct I56 is substantially the same. Between the discharge port of the transfer pump I36 and the fuel line I50 a fuel strainer or filter, not shown in the drawings, may be in serted.

In Figure 5 automatic safety devices are shown for shutting off the engine fuel supply. The engine-driven fuel transfer pump I36 including gears I40 and I44, draws fuel at substantially constant pressure from supply line I46 and discharges a weight of fuel proportional to the engine speed through a line 2I8 and an orifice adjustable by needle valve 220 into line 222 leading to the inlet manifold 92, thus determining on opposite sides of said orifice a difference of pressure that is proportional to the square of the engine speed. A plunger 224 slidably mounted in a bore formed in pump housing 226 is provided with an annular groove 226 in constant communication with line 222 and, through duct 230 drilled in plunger 224, with a chamber 232 formed at the lower end of the plunger and closed by a threaded cap. The upper and lower ends of plunger 224 are submitted to the pressure of the fuel respectively ahead and beyond the orifice controlled by needle valve 220 whereby a downwardly directed hydraulic load proportional to the square of the engine speed is applied to said plunger against the load of the spring mounted in chamber 232. When a predetermined engine speed is reached plunger 224 moves downward establishing by means of its groove 228 a communication between line 222 and a groove 234 connected with low pressure fuel supply line I48, thereby opening a by-pass between the discharge and inlet ports of transfer pump I36, thus causing the pressure in the fuel manifold to drop and stopping the fuel discharge of injectors 8. The engine speed at which the plunger 224 by-passes the transfer pump I38 may be adjusted by means of needle valve 220, or by varying the thickness of gasket 238 and th load of the spring mounted in chamber 232. Said speed is preferably substantially higher than the maximum speed at which the main governor may be set, and plunger 224 is therefore an auxiliary independent over-speed shut-off device intended to operate in case of failure of the main governor. It may, however, be used as a maximum-speed governor, for example, in connection with an internal combustion engine of automotive type.

Other simple, compact, and inexpensive safety devices may be provided for shutting off the engine fuel supply in response to variations beyond predetermined limits of temperatures, or pressures connected with the operation of the engine. In their preferred embodiment they include means for controlling a by-pass adapted to con- .nect the fuel pressure lines communicating with the fuel manifolds 92 and 98 with a low pressure supply line I48.

An example of temperature-responsive shut-off device is shown in Figure 5, in which a bulb 240 containing a liquid having a boiling point of a value such that at a predetermined temperature the fluid will produce a substantial increase of pressure in chamber 242 suitably connected with bulb 240 and closed by a membrane or bellows 244 adapted to actuate an axially slidable plunger 246 against the load of spring 248. Upward displacement of plunger 246 causes the groove 250 connected with line 222 to communicate with chamber 252 connected with low-pressure supply line I48, thereby determining a drop of pressure in the fuel manifolds and stopping the engine fuel supply. By means of a suitable duct drilled in plunger 246 the fuel pressure at the upper end thereof is kept at the same value as in chamber 252. Bulb 240 or equivalent temperature-responsive devices adapted to actuate plunger 246 may be mounted and arranged in suitable places so as to actuate plunger 246 and stop the engine when the exhaust temperature, or the lubricating oil temperature, or the cooling water temperature, or the temperature of any suitable part of .the engine reaches a predetermined value.

An example of pressure-responsive device is also shown in Figure 5, in which a fluid is led through pipe 260 to a chamber 262 closed by a membrane or bellows 264 adapted to actuate an axially slidable plunger 266 against the load of a spring. An annular groove 268 provided in plunger 266 is connected by means of suitable ducts with a chamber at the upper end of plunger 266 and chamber 210 communicating with the low pressureline I48. When the pressure of the fluid contained in line 260 and chamber 262 drops below a predetermined value plunger 266 moves downwardly thereby establishing a communication between groove 212 and chamber 210 through annular groove 268 and the axial duct drilled in the plunger, thus by-passing the transfer pump I36. An increase in pressure in tween groove 212 and chamber 210, as It has already been described in detail in connection with plunger 246. Line 260 may be connected with the lubricating oil line of the engine, the result being that when the pressure in said line is below a given value no fuel is injected into engine cylinders. The. fuel injection is also stopped when the pressure in said line increases beyond a determined value, as may happen when the oil filter is clogged.

In Figures6 and 7 there is shown an injector 280 similar to injector 6 but provided with different attaching means and fuel connections. Injector 280 has a flange 282 the lower surface of which is machined and adapted to be clamped on the upper machined surface of cylinder block 284 (or other suitable surface thereof), in which is provided an opening through which the lower part of injector 280 may be introduced in the tappet compartment 286. The injector fuel inlet 290 and fuel return outlet 292 are formed in said flange, communicating with fuel ducts 294 and 296 drilled in the engine block 284 and connected with fuel inlet conduit 298 and fuel return conduit 300 respectively, these conduits having the same function as the fuel manifolds 92 and 98 of Figure 1. Small fuel filters or strainers 302 may be provided in the fuel inlet and fuel outlet of injector 280, together with sealing means 304 consisting preferably of an annular member made of plastic or resilient material for preventing fuel leakage between flange 282 and cylinder block 284. A cap screw 306 having a threaded connection with the cylinder head 308 serves to clamp injector 280 in position, the load transmitted therebetween indicated by arrow 3I0, being substantially in line with the point of intersection of the axes of plunger I2 and noz zle 32, and having preferably the approximate direction of the bisectrix of the angle formed by said axes so as to be resolved into component loads indicated by arrows 3I2 and 3I4 of substantially equal magnitudes. Said components coincide approximately with said axes, thus eliminating the danger of bending the pump and nozzle parts of the injector, clamping the gasket I06 between nozzle tip 32 and cylinder head 308 and clamping flange 282 of injector 280 on cylinder block 284 thereby holding fuel seals 304 of the inlet and outlet of the injector 280 under compression. Centering shoulders 320 and 322 cooperating with cap screw 306 are provided in injector 280 for centering the latter and preventing sidewise displacement thereof.

It will be appreciated that injector 280 may b readily and easily removed from the engine and replaced thereon, without requiring any timing adjustment of the injection In order to remove the injector, cover 230 is disassembled and tappet rod I6 is disconnected from plunger I2; then cover 232 is removed and cap screw 306 is unscrewed, whereupon injector 280 may be withdrawn from the cylinder head 308. The same operations in inverted order are necessary for assembling the injector on the engineand reestablishing the fuel connections therebetween.

In the foregoing examples of preferred embodiments of the invention hydraulically controlled injectors have been disclosed, whose fuel delivery appropriate fluid other than the engine fuel may chamber 262 beyond a predetermined limit also causes a communication to be established bebe employed as hydraulic medium for the pressure-actuation of the injector rack 20, or other variable pressure may be used for actuating the fuel delivery control member thereof. Furthermore, a continuous flow of lubricating oil or other appropriate liquid coolant may be used to cool the injector. In any case theinjector is to be connected with one or more pipes or conduits for leading thereto, and possibly returning therefrom, an appropriate fluid such as the engine fuel, lubricating oil or other suitable liquid coolant, etc., and accordingly one of the objects of the invention resides in the provision of common means for readily and simultaneously clamping the injector on the engine and connecting it in flow communication with one or more pipes or conduits containing such fuel or other fluid. It will be readily understood that th injector 6 of Figs. 1 to 3. may be so modified, if desired, that one of the pipes 82 connected therewith will supply low pressure fuel to the inlet port I!) of the pump cylinder 8 thereof, while the other pipe may be used to lead another fluid, for example lubricating oil under variable pressure, to the chamber '54 at one end of rack 20 for the hydraulic actuation of the latter. In such a case the hydraulic governor will be used to control the ressure of lubricating oil in the latter pipe.

It will be further understood that in the case of the injector 280 of Figs. 6 and 7, more than two ducts opening in the injector flange and cooperating with an equal number of conduits opening in the corresponding flange-supporting engine surface may be provided. Thus in addition to the low pressure fuel lines connected with the inlet port I of the pump cylinder 8 for delivering fuel thereto, and venting the injector to prevent vapor-lock, two more conduits connected with chamber 54 and with appropriate cooling passages in the injector, may be provided for establishing a continuous flow of a suitable fluid such as lubricating oil we fer variable pressure to cool the injector, and exert an operative variable pressure-load on the control rack 20 thereof. In this arrangement said lubricating oil is employed as hydraulic medium in the governor of Fig. 1, and in the control devices of Fig. for the control of the engine fuel supply. No matter What the number of conduits Opening in the injector attachment flange and in the corresponding supporting engine surface, and no matter what the fluid 0r fluids in said conduits may be, a common fastening element such as bolt 306 may be used. The modifications which may be required in the injectors in order to use a fluid other than the engine fuel to cool the pump 8, and hydraulically control the rack 20, are evident and obvious to those skilled in the art.

It is further to be understood that according to the invention the injector need not be of the type including a pump and a nozzle body mounted transversely with respect to one another, but that any suitable type of injector adapted to be connected in flow communication with one or more fluid conduits, may be used in combination with common means for simultaneously clampin the injector on the engine, and tightly connecting said injector with said conduit or conduits.

These embodiments of the invention have been shown merely for purpose of illustration and not as a limitation of the scope of the invention. It

is therefore to be expressly understood that the invention is not limited to the specific embodiments shown, butmay be used in various other ways, and various modifications may be made to suit different requirements. and that other changes, substitutions, additions and omissions may be made in the construction, arrangement and manner of operation of the parts within the limits or scope of the invention as deflned in the following claims. Where the claims are directed to less than all of the elements of the complete system disclosed, they are intended to cover possible uses of the recited elements in installations which may lack the non-recited elements.

Certain features disclosed herein are claimed in my copending patent applications referred to above.

What I claim is:

1. In combination with an nternal combustion engine including a cylinder block having a machined surface, a detachable fuel injector ineluding an injection nozzle and a plunger pump having their axes substantially at right angles; a gasket at the end of said nozzle; flange means for said injector whereby the latter may be clamped on said surface with the axis of said pump perpendicular thereto; a fuel inlet and a fuel return outlet in said injector; fuel lines having their ends adapted. to be detachably connected with said inlet and said outlet; and attaching means for clamping said ends of said lines on said inlet and said return outlet thereby transmitting to said injector a load which is resolved into two component loads substantially in line with said two axes for clamping said flange means against said machined surface, and for applying sealing pressure to said gasket.

2. In combination with an internal combustion engine having a machined surface and a thrust surface, a fuel injector having a flange for attachment to said machined surface and including a plunger pump perpendicular to said flange and a nozzle body extending parallel to said flange and adapted to be held against said thrust surface; and attaching means for simultaneously clamping said flange against said machined surface and thrusting said nozzle body against said thrust surface.

3. In combination with an internal combustion engine having a plane surface and an annular seat for a nozzle body, a fuel injector having a face adapted for attachment to said plane surface, and a nozzle body substantially parallel to said face; and means for simultaneously clamping said face on said plane surface and thrusting said nozzle body against said seat.

4.. In combination with an internal combust on engine having a seat for an injection nozzle body, a plane surface and a fuel feed duct opening in said surface, a fuel injector unit including flange means for attachment to said surface, a plunger pump perpendicular to said flange means, conduit means opening in said flange means for leading fuel from said duct to said pump, and a nozzle body extending transversely with respect with said pump; and common means for holding said unit with said flange means and nozzle body clamped on said surface and seat respectively.

5. In combination with an internal combustion engine having a seat for a nozzle body, a plane surface, and fuel feed and excess fuel return ducts opening in said surface, a fuel injector unit including flange means for attachment to said surface, a plunger pump perpendicular to aid flange means, conduit means opening in said flange means for establishing a fuel flow communication between said pump and said feed and return ducts to ventand cool said injector, and

including a finished face, a fuel plunger pump perpendicular to said face, a delivery valve body extending transversely with respect to said pump and fuel inlet means, fuel conduit means adapted for connection with said inlet means, and common means for attaching said conduit means to said inlet means, clamping said face on said surface and thrusting said valve body on said seat.

7. In combination with an engine, a fuel injector including a plunger pump, a nozzle valve body extending transversely with respect with said pump, and a flange perpendicular to said pump for attachment to said engine, conduit means adapted for detachable connection with said injector to circulate a liquid coolant therein, and common means for connecting said conduit means with said injector and applying to the latter clamping loads in the directions of said pump and valve body.

8. In combination with an engine having a camshaft, inlet and exhaust valves actuated from said camshaft, a finished surface at definite distance from said camshaft, and a nozzle body seat, a fuel injector including a flange for attachment to said surface, a pump having a reciprocable plunger actuated from said camshaft and perpendicular to said flange, and a nozzle body extending transversely with respect to said plunger and a single threaded member for holding said injector with said flange clamped on said surface, and said nozzle body thrust against said seat.

9. In combination with an engine having a cylinder block provided with a machined surface, a cam at definite distance from said surface, and a cylinder head mounted on said block with a gasket interposed between block and head, a passage provided with a seat in said head, a fuel injector having a face for attachment to aid surface, a plunger pump perpendicular to said face and actuata-ble from said cam, and a nozzle body extending transversely with respect to said pump, and common means for holding said injector with said face clamped on said surface and said noz- -zle body thrust against said seat, with sufficient radial clearance between said passage and nozzle body to compensate for variations in the thickness of said gasket.

10. In combination with an internal combustion engine, a fuel pump and injection nozzle unit therefor, a seat in said engine for said unit, fuel conduit means adapted for detachable connection with said unit, and common attachment means for simultaneously connecting said conduit means with said unit and clamping said unit on said seat.

11. In combination with an internal combus tion engine, a fuel injector unit therefor including a plunger pump and a nozzle body, a. seat in said engine for said nozzle body, fuel pipes adapted for detachable connection with said unit to lead low pressure fuel to said pump and return the excess fuel therefrom, and common attachment means for connecting said pipes with said unit and thrusting said nozzle body on said seat.

12. In combination with an internal combustion engine, a. fuel injector therefor, a seat in said engine for said injector, duct means in said injector, conduit means adapted for detachable connection with said duct means for the circulation of a liquid coolant in said injector, and

vcommon attachment means for simultaneously connecting said conduit means with said duct sive means in said injector for controlling the fuel delivery thereof, a fluid conduit adapted for detachable connection with said injector for leading thereto fluid under variable pressure to actuate said pressure responsive means, and common means for simultaneously clamping said flange on said engine and connecting said conduit with said injector.

-14. An engine fuel injection pump having a fuel discharge passage, a thrust surface surrounding said passage and a plane surface substantially parallel to said passage for attachment of said pump to the engine, and a threaded member connected with said pump for exerting simultaneous fastening loads in the directions of said thrust and plane surfaces.

15. In combination with an engine having a plane surface and a seat, a fuel injection pump therefor including a fuel discharge passage, a thrust surface surrounding said passage, a flange substantially parallel to said passage, and fuel ducts opening in said flange, fuel conduits in said engine opening in said plane surface and adapted for connection with said ducts to lead fuel to said pump and return the excess fuel therefrom, sealing means deformable upon application 'of said flange on said plane surface to prevent fuel leakage therebetween, and a threaded member for simultaneously clamping said flange and thrust surface on said plane surface and seat respectively.

16. In combination with an internal combustion engine, a fuel injector unit therefor including a pump, a nozzle body, and fluid pressure responsive means for controlling the fuel delivery of said pump, a seat in said engine for said nozzle body, a pipe adapted for detachable connection with said unit for leading thereto fluid under variable pressure to actuate said pressure responsive means, and a retaining member for simultaneously connecting said pipe with said unit and clamping said nozzle body on said seat.

FERDINANDO C. REGGIO.

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