US2354403A

US2354403A - Fuel injection system

Info

Publication number: US2354403A
Application number: US346479A
Authority: US
Inventors: Reggio Ferdinando Carlo
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1940-07-20
Filing date: 1940-07-20
Publication date: 1944-07-25
Anticipated expiration: 1961-07-25

Description

July 25, 1944. F. c. REGGIQ 2,354,403

I FUEL INJECTION SYSTEM Filed July 20, 1940 e Sheets-Sheet 1 Q I L I INVENTOR July 25, 1944. F. c. REGGIO 2,354,403

FUEL INJECTION SYSTEM Filed July 20,1940 6 Sheets-Sheet 2 7 INVENTOR July 25, 1944. F. c. REGGIO FUEL INJECTION SYSTEM 7 v Filed July 20, 1940 6 Sheets-Sheet 3 R I M [/1 5 0 I 8 w 7 a 3 I B z 9 5 5 Z I M w B v I B .V\ 7 170 w 5 r I 2 m m W 9 6 2 5 INVENTOR y 1944. F.-c. REGGIO FUEL INJECTION SYSTEM 6 Sheets-Sheet 4 Filed July 20, 1940 lso ' INVENTOR Filed July 20, 1940 6 Sheets-Sheet 5 INVENTOR F. c. REGGIO 7 2,354,403

FUEL INJECTION SYSTEM July 25, 1944.

Filed July 20, 1940 6 Sheets-Sheet 6 INVENTOR duction manifold of the engine.

Patented July- 215, 1944 f UNl'lED STATES? PAT FUEL INJECTION "SYSTEM Ferdinando Carlo Reggio, Detroit,;Mich.,assignor* to Caterpillar Tractor Company, Peoria, Ill.

' Application July 20, 1940, Serial him 346,479

' 19 Claims; (cum-1'39) This invention relates to a fuel supply system for internal combustion engines and in particular to a fuel injection system for intermittently delivering liquid fuel under pressure and in measured quantities into the cylinders or into the in- More specifically, the invention relates to fuel injectors, including a fuel injection nozzle and a fuel pump mounted close together in a single housing or body so as to eliminate the necessity of having a long fuel line therebetweem Such lines containing a column of fuel of considerable volume r in relation to the volume of fuel discharged at each cycle by the pump and having a considerable length are particularly objectionable in "high-speed engines and in engines .in which the fuel is injected at high pressure, because the pressure sur-res and the eflect of the fuel corn pressibility therein, may adversely affect the accuracy of the'injection timing and the discharge characteristics of the nozzle.

Fuel injectors including an injection nozzle and a fuel pump arranged coaxially in a single body have long'been used. The pump is usually provided with a reciprocating plunger-actuated from the engine. camshaft by means of a tappet or reciprocating mechanism. One drawback of this arrangement is that the injector cannot be removed from the engine and replaced without disassembling the tappet mechanism. Further- -more, the injection timing has usually to be re- 1 adjusted every time that the injector is replaced.

- To obviate these disadvantages a desirable arrangement-consists of an injector unit including an injection nozzle element and a fuel pump element, said elements being mounted not coa'xially but at an-anglerelatively to one another. This angle may vary according to the specific re'quire- -ments of the engine. The injector may thus be mounted to one side of the engine cylinder where and connected with the cooperatingelements of the injector so as to eliminate the danger of distortion thereof. I I

Another object is to provide means for attaching the injector to theengine, whereby the'iniector maybe easilymounted and removed therefrom, and-whereby the timing adjustment of the injection may be. facilitated, 'or the necessity of suchan adjustment maybe eliminated.

- A still furtherobject is to providein an internal combustion engine .a fuel injection'system including interchangeable injectors of the character described which are mounted out of the zone of high temperatures from the combustion chamber; which areenclosed in the engine housing and readily accessible for inspection and replacement, and which maybe actuated from the engine camshaft-by meansv of inexpensive and compact reciprocating mechanism, whereby permitting an appreciable reduction in the cost and overall dimensions-of the engine. 1

The above and other objects of the invention will be apparent as the description proceeds; and

but they are intended to be as generic in-the apable, and which may be readily assembled;

which is economical to manufacture, and in which the accurately machined parts, such'as the pump barrel and the pump plunger are arranged Figure '7 is a section taken in a by lines 1-! in Figure 6;

- while I have. illustrated and described the pre- 1 .ferred embodiments ofthe' invention as they now appear tome, it will be understood that such changes may be made-as-fall within the scope of the appended claims. In thefollowing description and in the claims various details will be identified 'by specific names for convenience,

plication as the art will permit. The drawings show various embodiments of my invention.

Figures 1 to 4 showone formof injector of my invention in which the nozzleis of the open type arranged at right angles with the axis of the pump.-v Figure 1' is an elevational view;

Figures 2 and 3'are sections taken in planes indicated by lines 2-2 amid-3' in Figures 1 and 2 respectively. Figure 4 is a side elevational'view.

Figure 5 shows,'part in section and part in elevational view, another form of injector having ajnozzle of the open type.

Figures .6 and? show another form of injector having a. closed or difierential "type of nozzle. plane indicated Figures 8 to 10 show another form of injector having a closed-typenozzleh Figures 9 and 10 are sections taken inplanes. indicatedby lines 9-9 and l0|0 respectively in Figure 8.

Figure 11 shows a still different'fbrm of injec-'- tor provided with a nozzle-of the closed type;

I Figure 12 is-a sectional elevation of the mechathedelivery of the injecto provided with a passage vided between the fuel the latter leads fuel to rel 24 by means of a spacer 88,

assembled or taken apart.

. ing part of the invention includes a body or housing 22 inwhich is removably'mounted a pump barrel 24 provided with a fuel inlet port 28. A pump plunger 28 is mounted in barrel 24 and is I adapted to be reciprocated from an engine driven cam by a tappet mechanism 88. The plunger may be of any'suitable construction, preferably of the type inwhich the volume of fuel injected by the pump may be controlled by angular adjustment of the plunger about its axis. Such type of construction which usually includes annular groove 82 communicating with the pressure chamber 84 at the inner end of the plunger through an axial groove 88, and provided with at least one inclined scroll'edge 38 for covering and uncovering the fuel inlet port 28, is well-known in theart and it is therefore considered unnecessary to describe it in detail. A cap screw chined in the barrel 24 holds the latteragainst rotation. Plunger 28 is slidably but non-rotatably mounted in pinion 42 which engages a rack 44 reciprocable in a bore of body or housing 22, so that an axial movement of the rack causes a rotation, of plunger, 28 and in turn a variation of A- spacer 48 having a central fuel passage is mounted at the inner end of barrel 24', The housing 22 of the injector is with the axis of plunger 28 and in which is mounted a fuel conduit member 48 held in proper angular position by means of a dowel 88 engaging a slot formed'in the wall of passage". The outer end of-conduit member end'of the wall of passage 48, while the inner end thereof is provided with ahead 8| adapted to seat against spacer 45 and formed withacavity containing a check or non-return valve 82. The central or intermediate portion of conduit member 48 is formedwith a narrow section so as to be resilient and to yield within designed limits.

Against the outer end of such conduit member:

48 is mounted the nozzle tip member 88 held by means of cap 84 screwed onto the wall of passage 48. \A spring-loaded, non-return valve 88 is proconduit member 48 and nozzle tip member 88; and a duct axially drilled in the discharge orifice 81.

48 engaging a slot ma-.

48 formed at right angles 48 is seated against the The head 8| at the inner end of fuel conduit memheld against the barkept from rotatin groove'connection 88, which in by a screw plug 88. An annular ber 48 and thespacer 48 are by a screw and turn is clamped by the load applied to perpendicular to the axis of ass-1,403

tion thereof, hence, against spacer 48 by means of spacer 88 and screw plug 88 deformation of some element of the injector structure will necessarily occur. Since'the intermediate portion of conduit member 48 is made of comparatively narrow cross section, this portion will yield, that is bend, or twist, or both, without opposing any appreciable reaction that, transmitted to the barrel 24, might cause the latter to bend, thereby adversely aflecting the operation of the-pump.

when the head 8| is clamped The plunger 28 is formed with'a head 82 and v a groove 83 adjacent the outer end thereof adapted to provide a head and T-slot detachable connection with a tappet mechanism 88.

Fuel enters the injector communicating with port cess fuel flows through barrel 24 to passage through outlet 88 connected with passage 48. This flow of fuel, determined by a difference of pressure between fuel inlet 88 and fuel outlet 88, vents the injector of all bubbles of air, vapor or gas that separate from the fuel, and which, if it were permitted to reach 28 of barrel 24, and exgroove 81 machined in tached to the engine and held in an accurately determined position relative to the tapbet or reciprocating mechanism. To that end the injector 22 is formed with a flange I8 extending in a plane normal to the axis of the nozzle and which has spaced holes II for receiving, guiding and centering dowels l2, and spaced holes 14 for receivin securing cap screws or studs 18.

The'dowels l2, permanently'secured to the engine and having accurate close lit in the holes hold the injector 22 centered in the proper position relative to the operating cam and reciprocating mechanism, and prevent the injector from being misaligned due to the thrust imparted thereto the plunger 28 by the tap- Furthermore, since the dowels 12 are the plunger 28' and the latter is centrally located relatively to the flange 18, no appreciable distortion or deformation of body 22, and in particular no bending of the walls of passage 48 may occur. The cap screws or studs 18 parallel to the dowels I2 pass with radial clearance through apertures 14 and have a threaded connection with a suitable part of the engine structure. They hold the nozzle gasket 18 or other equivalent sealing means clamped against a shoulder provided in the engine as it will be disclosed later in detail.

A further. embodiment lustrated in Figure 5 in which the injector body pet 38,

seal 8| interposed therebetweenprevents'leakage of fuel past the screw plug. All the parts of the injector In assembling, rack 44 is mounted in its bore; pinion 42, plunger 28, barrel 24 and spacer 48 may be introduced from the top in body 22; then the conduit member 48 is mounted endwise through passage 48 and clamped therein by means of nozzle tipmember 88 and cap 84. It will be realized that however accurate the machining of the various parts'involved may be, the head 8| of the inner part of conduit member 48 will hardly be in contact with spacer 48 at all points of its designed surface, but said contact will more likely be limited to some peripheral pormaybe very easily 8| mounted at right angles with barrel 24 and having a fuel passage therein in communication with, the nozzle discharge orifice 51. A

- wedge-shaped member 82 is adapted to be clamped means of a wedge-shaped spacer 84 held from simultaneously against the adjacent plane surfaces of spacer 45 and nozzle member 8| by rotation by a screw and slot connection 88 and clamped by screw plug 88. When the latter is tightened a load is transmitted by spacer 84 to member 82. The resultant of said load is applied to member 82 approximately at the point of intersection of the axis of the barrel 24 and nozzle member 8|, and is therefore decomposed in two component loads substantially coaxial with said b r l and said nozzle, thereby eliminating the 48 and leaves the injectorthe pressure chamber 84 through port 28, might interfere with the correct of the invention is ilthrough an inlet 88 r such conduit member needle valve I32,

- in which a split gear sector means of screw I45 and thus rethe plunger. A rack I41 slidably rectly on pump barrel 24, thus Y necessity of having an intermediate spacer simiar cavity provided danger of distortion or asymmetric deformation thereof. Member 02 has a fuel duct 80 therein to establish fuel communication between barrel 24 and nozzle member I. Check valve 52 and spring .-l0aded non-retum valve 50 are provided. This nozzle is otherwise similar to that disclosed in connection with Figures 1 to 4 and it is therefore regardedunnecessary indetail. a

The nozzles of the previously described injectors are of the open type. In Figures 6 and. '7 is illustrated a modified form of injector'in which the nozzle is of the closed or differential tyre Most-points of such injector are similar to those already described in the foregoing. Injector housing or body I includes a pump barrel 24 clamped in position by means of a screw p'ug 00 bearing against spacer I2 I, which in turn bears against inner head I22 of conduit member I23. having a narrow resil nt intermediate portion I24 extending through nzzle passage I25 providing a fuel cooling chamber.

A nozzle tip member I20 seats against the outer surface of conduit member I23 and is carrpcd in position by cap 54, a. pin and slot connection I serving to hold conduit member I23 in prop r angular adjustment relative to body I20. Norze' 20 includes an axially reciprocable needle valve I32 controlling the fiow'of fuel to the discharge orifice 133. A rod I34 extending with radial clearance through an opening provided in spacer I2 I and through passage I25 transmits the load of spring I35 to needle valve R2. Adjustable stop I30 serves to limit the lift of and a threaded cap I31 is pro vided to adjust the load of'spring I35 and thcr g by determine the fuel pressure at which the va ve I32 opens to allow delivery of fuel through to the orifice I33. The entire spring assembly is en-' closed'byacap I30.

Fuel enters the injector through the fuel inet line I40 detachably connected therewith. Excess fuel and leakage fuel that might flow past ihe needle valve I32 collects into passage I25 and is led back to the source through a fuel return tip member I line I thereby venting and cooling the injector I20. While the mechanism for controlling the angular adjustment of the pump plunger mi-bt be similar to those previously described, a sli htly modified construction is shown in Figures 6 and '1 I43 is secured to pump plunger I44 by ciprocates with I mounted in notches formed in extensions carried by housing I20 and held by a detachable reta ning' member I40v engages with gear sector I43 whereby axial reciprocation of rack I41 results n angular adjustment of plunger I44. The lower end 'of retaining memberI40 is adapted to ure- 7 vent the plunger I44 from being dropped while the injector I20 is not mounted on the engine and connected with the tappet the plunger I44 not mechanism. Also a slightly different arran ment of check valve is shown in Figure 1 in which valve I50, enclosed in suitable chamber formed in to again describe it mounted in passage I55 formed in injecto'r'hous-, ing I50. Su ch fuel conduit member I54-has an inner head I51 between

spacers

45 and 50, and an outer seating part I clampedbetween nozzle tip member I28 and the walls of passage I by means of cap 54 and J'oined to head I51 by means of two integrally connected spaced arms I50 between which spring I52 is mounted. One of sa d arms has a fuel duct I00 therein connecting the check valve 52 with the needle valve I32. spacer I02 serves to limit the lift of needle valve I32. Arms I53 forming the intermediate portion of conduit member I54 have a small section and are thus highly resilient, whereby conduit member I54 ma bend or twist as it has already been disclosed in detail in connection with the injector of Figures 1 to 3, without opposing appreciable reactions tending to bend the pump barrel 24.

A stillfurther modification is indicated in Figure 11 showing an injector I05 substantially'similar to injector 00 of Figure 5 but .having a nozzle of the closed or differential type including a nozzle tip member I00 having'a reciprocable needle valve I32 therein loaded by spring I01 contained in the spring cage. I00 provided with a fuel duct about the nozzle tip member I06.

Figure 12 illustrates-the mechan sm of my in vention in association with an internal combustion engine of the compression-ignition or Diesel type having a cylinder I80 with a piston IOI reciprocable therein and a precombustion chamber I02 mounted in 'a suitable cavity provided in, the

engine block I03 at one side of the cylinder I80 and surrounded by a cooling water jacket I04.

Chamber I82 is connected through a passage I05 with cylinder I00, held in proper angular position relative thereto by a pin and groove connection I00, and.clamped in position by-the engine head I00 resting on the engine block I83 with theusual cylinder head gasket I03 interposed between the block and the head.

A sleeve I30 traversing the outer and inner walls of thewater-iacket I04 and the wall of the precombustion chamber I82 is provided with passage. I3I' extending from the chamber I02to the inJector compartment I02 and is adapted to receive the nozzle part I03 of an injector I34 which may beslmilar to any of the previously de- -.Figures l'to 5 and 6 to 11 of the drawings.

example, two studs 15 parellel to the axis of the Y inner end I22 of conduit member I23. rests dito that indicated by number 45 insom of the drawings previously referred-to.

The modification illustrated in Figures 8 to 10 6 and '1 in that the fuel conduit member I54 eliminating th e- I20 is contained in av 'SleeveI00 has a shoulder I against which the nozzle tip seating part, such assealing gasket I01 mounted at theend of the nozzle part I33, is adapted to be thrust byattaching means, for

nozzle I13 and secured to the wall I30 of the engine block iI83, and nuts I90. Spaced dowels 12, also para la] to the axis of nozzle I03 and fixedly secured to the wall I00 of the engine block I03, are adapted to be received with accurate fit in holes 1I- (shown in Figure 1) of flange 10 of injector, thus centering and holding the latter in a predetermined position. Radial clearance is provided between nozzle part I33 of the injector I34 and sleevel00 and between attaching studs '75 15: and receivingholes .14 therefor made in flange when the injector is clamped in position.

Axial reciprocation of rack 44 and thereby angular adjustment of pump plunger 28 of injector I94 is effected through a govemor-controlled fuel control mechanism which comprises a rod 28I parallel to rack 44 'slidably mountedin brackets 282 carried by engine wall I 98, and a connecting arm 288 secured to rod 28I and extending perpendicularly from'such rod to engage a slot formed in rack 44. Since the latter'is mounted in housing of injector I94 for axial reciprocation in a direction which is at right angles with guiding and centering dowels'12, and that portion of connecting arm 288 which engages rack 44 is parallel to such dowels, it is clear that variations in the position of injector I94 'such' as might be caused bychanges in the thickness of nozzle gasket I91 do not alter the position of rack 44 relative to injector I94 and therefore do not affect the fuel delivery thereof.

A camshaft 285 is supported in bearings carried by the-engine blockv I88 and serves to actuate through push rods 288 the inlet and exhaust valves, not shown in the drawings, mounted in thehead I88 of engine. Any suitable tappet mechanism for actuating the plunger 28 of injector I94 from said camshaft may be provided.

A convenient arrangement, shown in Figure 12,-

includes. a cam follower of the mushroom type 288 reciprocably mounted in a bearing 289, carried by the engine block I88 and provided witha cavity therein containing lower and upper seat members 2 and 2I2 respectively urged againstone another and.against the end of said cavity by the lower end of the coil spring 2I8, the upper end of which is seated against collar 2I4 held by retaining ring 2I5;mounted in a groove formed in bearing 289.

A tappet rod 2I'I is provided at its lower end withan expanded head 2 I8 held with small clearance between seat members 2 and 2 I2, while at its upper end it carries a connecting member 228 attached to said rodby means of a-threaded connection and a lock nut 22I. Such connecting member 228 includes a head 222 formed with a' T-shaped slot 228' having a close fit with a head 224 and'a groove 225 formed at the lower end of pumpplunger 28. A U-shaped retaining member 221 slidably mounted about connecting member '228 is. upwardly urged by a spring 228 to lat-.

'It is therefore clear that tappet rod 211' is,

centered at its lower and upper ends by the cam follower 288 and by the pump plunger 28 respectively, thus eliminating the necessity of providing guiding or supporting meanstherefor,.and

the pump plunger 28. Thus, spring 2I8-holding cam follower 288 in contact at all times with the cooperating cam carried by camshaft 285 also effects the return or suction stroke of the pump plunger 28 of injector I94.

" In the preferred embodiment of the invention the cam follower 288 and the tappet rod 2I'I are coaxial or substantially coaxial with the pump -p1'unger 28 of the injector I 94; hence, slight I8 of injector I94 so as to avoid any binding" changesinthe'position of injector I84 compatible with the centering action-of dowels I2, that is slight variation in the position of the injector.

along the axis of the nozzle part I98 which is-at right angles with thepump plunger-28, such asv might be caused by changes in the. thickness of nozzle gasket I91, do not cause any appreciable modification in the adjustment ofpump plunger 28 relative to dowel 24 and therefore do not affect the timing of the injection. Furthermore-1th to'be noted that in the example of Figure 12 both the centering dowels I2 for the injector I94 and the bearings bf the camshaft 288 are supported by the engine block I88. According to the invention the distance therebetween, the radii of the cam, and the length of the tappet mechanism are all accurately kept within close predetermined tolerances; the result being that when the camshaft 288 is in a given angular adjustment, for example corresponding-to the point of minimum lift of the tappet mechanism, the T-shaped slot 228 of the connecting member 228 thereof and in turn the head 224 of pump plunger 28 are with- "in a close predetermined tolerance at a definite distance from the guiding and centering dowels I2. Preferably, the various elementary parts included in the tappet mechanism which determine the total length thereof are machined within strict tolerances so that they are interchangeable and may be individually replaced without modifying the position of pump plunger 28 relative to the dowels I2.

In injector I94, when the head 224 of pump plunger 28 is ,at a definite distance from the receiving holes II for the centering dowels I2, that portion of the plunger 28 which is adapted to cover and uncover the inlet port 28, and. thus controlsthe injection, is at corresponding predetermined axial distance, from said port 28, whereby all injectors I 84 are interchangeable and may be replaced without'afl'ectingthe injection timing.

It may be shown that slight variations in the lengths of the various parts of the tappet mechanism and ofthe injector within reasonable manufacturing tolerances causevariations 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 separat injection nozzle and fuel pump interconnected by a comparatively long highpressurefuel line wherein pressure surges and fuel compressibility adversely affect the injection characteristic.

' The injection compartment I92 is enclosed by a cover 288. Fuel is led to the injector and the excess'th'ereof is returned to the source' through fuel lines detachably connected Withthe injector such as that indicated by 28I in Figure 12. From the foregoing it will be appreciated that'the injector I94 may be readily inspected and replaced,

which is important not only in manufacturing but also in servicing in the field. In order to replace the injector I94 it is sufficient to remove cover 288, disconnect fuel lines 28I from the injector, disconnect the tappet mechanism 2" from the pump plunger 28 while the retaining member 221 is being held in the position indicated in Figure 14, and remove nuts I99, whereupon, th injector may be withdrawn. v

Since all parts are enclosed within the engine blocl: and therefore protected from dirt, dust, and water,vthus eliminating all danger of oxidation the foregoing operations may be readily acc'oml plished. The inverted operations are made when the injector is mounted on the engine: in doing so the groove formed in rack 44 may be easily indicated in Figure 15 shows an engine in which the camshaft 205 is supported in the engine block 234, but in which the precombustion chamber 236 is located in the cylinder head 23! clamped on the engine block with the usual cylinder head gasket 238 interposed therebetween. In such type of engine an injector I94 which may be similar to any of the previously described injectors I is provided to inject fuel into the precombustion chamber 23' thereof. As previously stated, it is important that the distance from the cam profile on camshaft 205 to the guiding and centering dowels 12 be held within close limits in order to obtain correct timing of the injection. However, variations in the initial thickness of gasket 238 and in the degree of compression thereof when clamped between head 23'! and block 234 cause changes in the distance therebetween. Thus, instead of securing the guiding and centering dowels 12 to the cylinder head 231, they are carried at a closely determined distance" from the camshaft by suitable supporting means accurately positioned on the engine block 234. The bracket 240 centered on cylinder block 234 by means of dowel pins 242 and secured, thereto by studs threaded into the block and nuts 243, has spaced upwardly extending arms 244 in which theguiding and centering dowels 12 have a press flt. The injector I94 is guided and centered by said dowels, while studs 246 secured in the cylinder head 23'! and passing with suitable radial clearance through openings 14 of flange and nuts I99 having a threaded connection therewith are provided for clamping the injector I94 so that the sealing gasket I91 mounted on the nozzle part I33 thereof is thrust against shoulder 243 adjacent combustion chamber 236. Nozzle part I33 is mounted in the cylinder head with radial clearance so as to avoid any binding as the injector is clamped-in position.

Any suitable tappet mechanism may be pro- I vided for actuating the pump plunger 23 from the camshaft 205. In the embodiment of the invention, shown in Figure 15the tappet mechanism includes a cam follower 250 provided with a roller 252 and mounted for axial reciprocation in a bearing provided in bracket 240. .A spring 254 maintains roller 252 at all times in contact,

with the cam. The upper end 30 of cam follower 250 connected with pump plunger 28 is in detail in connection with the arrangement illustrated in Figure 12.

In the foregoing, two examples have been disclosed in which the engine camshaft is supported in bearings carried by the engine block, fuel being injected either in the engine block or in the cylinder head, the arrangement being such that the injectors may be replaced without requiring timing adjustment of the injection. According to the invention the same result may be obtained when the camshaft from which the injector is actuated is supported in bearings carried by the cylinder head, the fuel being injected either in the cylinder head or inthe cylinder block, the essential necessary condition being that the centering dowels for the injector be accurately held at a predetermined distance from the camshaft.

similar'tothat shown in Figure 2, and since the cam follower 253 is guided and maintained at all times coaxial with pump plunger 28, no retaining member similar to that indicatedby numeral 221 in'Figures l2 to 14 is required; Injector rack 44 is controlled by arm 233 secured to rod 20L Tappet mechanism for actuating intake and exhaust valves mounted in cylinder head 23! (not shown). from camshaft 205 may be provided, including cam followers guided in suitable bearings formed in bracket 240 and tappet rods 24$.

' It will be apparent that the accuracy of the injection timing, the elimination of the timing ad justment and the interchangeability and accessibility of the various parts of the modification ascompression-ignition, or Diesel engines.

In the foregoing, injectors have been described in combination with liquid-cooled internal combustion engines'of the type generally referred to It is to be clearly understood that according to the invention the injectors may be used in combination with any suitable type of internal combustion engine including both. spark-ignition and compression-ignition engines, the latter having either direct injection or precombustion chamber, Furthermore, the injectors may discharge the liquid fuel not only in a precombustion chamber or in the main combustion chamber of the engine cylinder but also in the engine induction system, for instance'in the engine intake manifold of a spark-ignition engine ahead of the intake valve. Figure 16 illustrates, as as exam- 4 pie, the application of an injector 280 discharging fuelinto the combustion chamber 282 of an air-cooled engine having a cylinder head 284 secured to. the engine cylinder 286. Such air-cooled engine maybe either of the spark-ignition or of the compression-ignition type. Injector 230,

which may be provided with cooling fins 283.

head 284 by means of guiding and centering dowels 233 secured thereto and having at their outwardly extending end a threaded connection with the nuts 232 serving for clamping the injector 283 on the cylinder head 234 with the usual nozzle gasket 23. interposedtherebetween or equivalent sealing means. Fuel lines, not shown, are provided for detachable connection with the fuel inlet 29l and fuel return port of the injector. A control linkage, also not shown in the drawings, is provided for controlling the rack 44 of ,the injector. The tappet mechanism operating the pump plunger 23 from a suitable cam is shown similar to that described in connection with Figures 12 to 14 and is enclosed by a tubular memher 300 as it is customary in aviation engines of the radial type. Injector 23fl,may be of the design inwwhich the nozzle part thereof is at right angles with the pump plunger- 23 and the arrangement may be such that the tappet ,mechanism is coaxial with the plunger 28, in which case if the distance between the dowels 230- and the cam profile is kept within close limits no timing adjustment is required, as it has been point- 0 7 2" and pump plunger 28 thereof may be slightly larger than degrees, in which case if the thickness of gasket 2" is keptwithin close limits the injector 283- may still be replaced without reshown in Figure 15 are similar to those described In quiring readjustment of injection timing thereof.

Figure 17 shows the application of injector 280 to a spark-ignition engine having a combustion chamber 304 in the cylinder head 306 thereof communicating through port 308 controlled by intake valve 3I0 with manifold 3l2. Injector 280 intermittently discharges liquid fuel in said manifold 3|! ahead of valve 3). Usually when fuel is injected in the manifold of spark-ignition engines'the duration of the injection is considerably is therefore to be expressly understood that the invention is not limited to the specific embodiments shown but may be usedin 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 defined in thefollowing claims.

What I claim is:

1. An interchangeable fuel injector unit for internal combustion engine including a delivery nozzle body and a plunger pump mounted in said -unit tranversely with respect to one another;

means independent of said nozzle body for guiding and centering said injector unit on said en-' gine; and fuel control means in said injector unit including cooperating rack and gear for controlling the angular adjustment of the plunger of said pump, said rack having its' axis in a plane normal to the axis of said plunger and to the axis of said nozzle body.

2. In combination with an internal combustion engine, a fuel injector therefor including housing means, a plunger pump and a nozzle valve mounted therein with their axes at right angles; an engine-driven cam; a tappet mechanism for imparting a reciprocating motion of constant stroke to the plunger 'of said pump from said engine and injector including centering dowels whereby said injector is guided in the direction of the axis of said nozzle and centered on said engine in a predetermined position relative to said tappet mechanism whereby said injector may be replaced without requiring adjustment of the injection timing thereof.

5.'In combination with an internal combustion engine, an interchangeable fuel injector therefor including a delivery nozzle valve and a plunger pump mounted therein with their axes at right angles, said injector being adapted to be clamped on said engine with sealing means interposed between said nozzle valve and said engine; ran engine-driven cam supported in bearings carried by said engine; tappet means in said engine .for actuating said injector from said cam;

and dowels carried by said engine and cooperating with-bores formed in said injector for holding the latter with the axis of said nozzle valve at a definite distance from said cam whereby said injector may be replaced without requiring adjustment of the injection timing regardless of "changes of initial dimensions and deformations of cam; and guiding means at opposite sides of said plunger for centering said injector with respect to said engine. whereby said injector ismounted thereon and removed therefrom with a movement of translation in the direction of the axis of said nozzle valve without necessitating disassembling of said tappet mechanism.

3. In combination with an internal combustion engine, a fuel injector unit therefor including a nozzle valve part and a plunger pump part mounted therein with their axes at right angles;

an engne-driven cam; guiding means independent of said nozzle valve part for centering said injector with respect to said engine at a predetermined distance from said cam; and a tappet mechanism including a tappet rod substantially coaxial with said pump for imparting a'reciproeating motion of constant stroke to the plunger thereof from said cam. v

4. In combination with an internal combustion engine, an interchangeable fuel injector therefor including an injection nozzle valve and a pump having their axes at right angles; said pump including a cylinder having port means and a plunger reciprocable in said cylinder and controlling said port means; an engine-driven cam; tappet mechanism for transmitting a reciprocating motion of constant stroke to said plunger from said cam; and cooperating means in said said nozzle and said engine; means including a rod substantially coaxial with said plunger for reciprocating said plunger from an engine-driven cam; centering means for guiding said injector with respect to said engine in the direction of the axis of said nozzle; fuel control means carried by said injector and including cooperating rack and gear for controlling the angular adjustment of the plunger of said pump, said rack having its axis in a plane normal to the axis of said nozzle and a detachable connection at right angles with control means carried by said engine, whereby changes in the position of said injector relative to said engine in the direction of the axis of said nozzle due to variation of the dimensions of said sealing means affect neither the delivery of said injector nor the injection timing thereof.

7. In combination with an internal combustion engine, an interchangeable injector having housing means; a fuel delivery nozzle and a plunger pump mounted in said housing means transversely with respect to one another; centering means carried by said engine for guiding said injector in a direction parallel to axis of the said nozzle; an engine-driven cam, tappet mechanism for actuating the plunger of said pump from said cam and including a cam follower and a tappet rod. both substantially coaxial with said plunger; a detachable head and T-slot connection between said plunger andsaid rod whereby said plunger and rod may be connected and disconnected by means of a sidewise relative displacement therebetween; removable retaining means for preventing said sidewise relative displacement; and resilient means in said tappet mechanism for holding said tappet rod in contact with said cam follower and the latter in contact with said cam whereby the suction stroke of said plunger is effected by said resilient means through said tappet rod.

8. In combination with an internal combustion engine, an interchangeable fuel injector therefor having a housing, a fuel delivery nozzle and a plunger. pump mounted therein transversely with respect to' one another; a reciprocating mechanism' for actuating the plunger of said pump; guiding means carried by said engine and cooperating with receiving means fixedly connected with said housing on opposite sides of said plunger whereby said injector is adapted to be guided in the. direction of v the axis of said nozzle; the axis of said plunger being centrally located between the cooperating portions of said guiding and receiving means whereby the load transmitted by said reciprocating mechanism to said plunger does not cause any appreciable deformation of'said housing.

9. In combination with an internal combustion engine having a cylinder and an engine-driven .cam, a fuel injector unit adapted to be detachably mounted on one side of said cylinder and including a delivery nozzle body extending transversely with the axis of said cylinder and a plung- 13. A combination as set forth in claim 2, said inject r housing means also including removable connecting means for establishing a fuel flow 114s. In combination with an engine having a fuel injection nozzle passage, an injection unit -having housing means comprising a plunger er pump directed toward said canij a reciprocating mechanismsubstantially coaxial with the plunger 'of said pump and detachablyconnected therewith for actuating the latter from said cam; and centering meansindependent of-said nozzle body for holding said injector in a predetermined position relativ to said tappet mechanism corresponding to a definite injection timing without causing deflection of said nozzle body.

10. In combination with an internal combustion engine having a cylinder block and a cylinder head on said'block, a gasket between said block and said head; a'n interchangeable fuel injector unit supported by said block and including a delivery nozzle body and a plunger pump arranged transversely with respect to said body; said nozzle body extending'with radial clearance into a nozzle passage formed in said head; an

engine-driven cam supported in bearings carried pump and a nozzle valve body removabiy mounted therein at right angles with respect to one another and removable connecting means for establishing a fuel flow communication between saidpump and valve body; means for clamping said connecting means on said pump and valve body with sealing pressure, directed substantially along the axes of said pump and valve respectively whereby no distortion of the injection unit parts occurs upon assembly thereof; and cooperating means in said engine and unit for cening'means in said housing means for establishing said connecting means on said pump and another portion thereof on said yalve, part of said connecting means between saidportions thereof having reduced section thereby rendering the latter a tappet mechanism fOnreciprocating the plunger of said pump froman engine driven cam, and bores insaid unit parallel to saidvalve and.coopcrating with positioning means carried by said cylinder for centering said-unit at a predetermined distance fromsaid cam.

12. In combination with an internalcombustion engine, an interchangeable fuel injection unit including a delivery nozzle and a plunger pump mounted transversely with respect to one another; cooperating guiding means in said englue and unit whereby the latter is mounted on and removed from saidengine'with a translation in direction of the axis of said nozzlei reciprocable tappet in us substantially coaxial with the plunger of s id pump for actuating said plunger from an engine driven cam; a detachable head and T-slot connection between said means adapted to yield to conform with the cooperating surfaces of said pump and valve without transmitting appreciable distorting reactions thereto,means for reciprocating the plunger of said pump, and cooperating means in said engine and unit for holding the latter at opposite sides of said plunger.

16. In combination with an internal combustion engine, an interchangeable fuel injector therefor having housing means, a nozzle valve and a plunger pump mounted therein with their axes at right angles, flexible conduit means in said housing means for leading fuel from said pump to said valve, means for clamping one end of said conduit means on said pump and the other end thereof on said valve, and cooperating means in said engine and housing means for guiding said injector in the direction of the axis of said nozzle valve.

17. In combination with an internal combus tion engine, a fuel injection unit including a plunger pump and a nozzle valve arranged trans-,

versely with respect to one another, flexible con' duit means in said unit for leading fuel from said pump to said valve, means for connecting said conduit 'means'with said pump and valve,

and means for securing said unit on said engine without causing distortion of said nozzle valve. 18. In combination with an engine having a cam, a fuel'supply unit therefor having housing means, a cylinder and fuel pressure outlet valve means non-coaxially held by said housing means, a plunger in said cylinder actuated from said cam, flexible fuel conduit means connecting said cylinder and valve means, and means symmetri cally arranged with respect to said cylinder for attaching said housing means to said engine.

19. In combination with an engine having a cam, a fuel supply unit therefor having a cylinder and fuel outlet valve means at right angles, a plunger in said cylinder actuated from said cam, two cylindrical bores formed in said unit parallel to said valve means and symmetrical with respect to-said cylinder, two centering dowels carried by said engine fitting into saidbores to bear the operative load transmitted to said unit from said cam, and threaded clamping members also parallel to said valve means andarranged symmetrically with respect thereto for securing said unit to said engine.

FERDINANDO C. REGGIO.