CA1069004A - Electromagnetically operated fuel injection valve - Google Patents
Electromagnetically operated fuel injection valveInfo
- Publication number
- CA1069004A CA1069004A CA320,577A CA320577A CA1069004A CA 1069004 A CA1069004 A CA 1069004A CA 320577 A CA320577 A CA 320577A CA 1069004 A CA1069004 A CA 1069004A
- Authority
- CA
- Canada
- Prior art keywords
- fuel
- terminal
- valve
- inlet
- actuator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Fuel-Injection Apparatus (AREA)
Abstract
ABSTRACT
A fuel inlet assembly for a fuel injection valve comprises a coil bobbin having at least one terminal insulating post extending axially through a radial flange on the inlet connector. The post has an axial terminal slot therein to receive a thin section of a terminal and comprises a welding-and-dimple aperture directly over the terminal slot ending in a radial dimple locking wall thereover. The terminal comprises a dimple across substantially the entire narrow width thereof, the dimple cooperating with the dimple locking wall after the terminal is inserted into the terminal slot to retain the terminal therein.
A fuel inlet assembly for a fuel injection valve comprises a coil bobbin having at least one terminal insulating post extending axially through a radial flange on the inlet connector. The post has an axial terminal slot therein to receive a thin section of a terminal and comprises a welding-and-dimple aperture directly over the terminal slot ending in a radial dimple locking wall thereover. The terminal comprises a dimple across substantially the entire narrow width thereof, the dimple cooperating with the dimple locking wall after the terminal is inserted into the terminal slot to retain the terminal therein.
Description
This invention relates to a fuel inlet assembly for a fuel injection valve.
This is a divisional of copending Canadian Patent Application Serial No. 273,500 filed on March 8, 1977.
This application is related to commonly-assigned Canadian Applica-tion Serial NoO 273,~6~, filed March 8, 1977 by Bode and Kiwior, entitled "Fuel sreak~up Disc for Injec-tion Valve".
Description of Prior Art Conventional fuel injection valves, such as of the type disclosed in the U.S. patent to Kirsch 3,R28,247 issued June 25, 1973, comprise one of the most expensive components of fuel injection systems in current mass production for passenger vehicles. Such conventional injectors incur such comparatively high costs because most of the structural elements effecting fuel breakup, fuel spray angle, fuel metering, and flow on/off valving are made to extremely close tolerances. Meeting these tolerances requires specialized lapping by a tool that cannot be used again for final lapping, and the resulting parts are custom rather than randomly mated. Even then such conventional fuel injec-tion valves do not normally breakup the fuel into controllably uniformly small particles and thereby limit the attainment of both maximum fuel economy and minimum formation of undesirable emissions.
Moreover, comprising extremely-narrow and closely-toleranced fuel meteriny and breakup paths, such conven-tion~l valves are susceptible to the deleterious effects of contamination passing the inlet filters of the injectors or back flowing from engine inlet passages into the injector outlet sec-tions.
It is therefore desirable -to reduce the cos-t of fuel . - - 1 -sb/`~
injection va~ves by avoiding -the conven-tional lapping and redressincJ, cus-tom hand ma-ting, and generally tight tolerancing all over.
A prlmary factor imposing harsh tolerancing requirements on such conventional fuel injection valves is the use of different elements of just one part, a reciprocating pintle-type needle-valve member, to perform the breakup, metering, and valviny functions. Each such different element must be closely concentric not only with the other elements of the same part but also with each of the surrounding structures cooperating with such elements.
The present invention recognizes that at least the close concentricity tolerances could be substantially relaxed and in turn other gross cost savings obtained by effecting the on/off valving function by a structure substantially separa-te from that effecting the fuel break-up function and the metering function. More specifically, recognizing that a circular seating edge need not be closely concentric with the metering orifice, the inven-tion allows the use of no less than three cost saving processes:
1) the conventional loose-concen-tricity low-cost "ballizing"
process of forcing a final diameter precision ball through an initially undersized aperture to repeatedly provide highly finished uniform orifices; 2) the conventional loose-concentricity low-cost "coining" process of forcing a precision ball against a softer conical surface to repeatably provide a circular non-leaking sea-ting edge;
and 3) the conven-tional loose-tolerance ball valve head and oversized ball seat technique to repeatably effect the on/off valving. Thus, even though ~he U.S. patents to Mattson 1,360,558 issued Novembcr 30, 1920 and Seccombe sb/~ ~
~,5~7,269 issued June 2~, 1971 sugges-ts -the use oE
ballizing, even though the paten-t to Carlson 3,400,~40 issued September 10, 1968 sugges-ts a ~uel injection valve having a ball seat coined by a slightly larger ball, and even though the patent to Malec 3,490,701 issued April 22, 1968 suggests the use of a stem-mounted ball valve, such prior art not withstanding fuel injection valves are not known to have heretofore used any com-bination of a ballized metering orifice, with a coined valve seat, or a stem-moun-ted ball valve head, perhaps because o~ the severe concentricity requirements previously thought to be essential.
As indicated above, a primary function of a fuel injection valve is to break up a metered quantity of fuel into combustible particles. Generally, the smaller the fuel droplets, the more readily they vaporize for combustion and the more completely they burn. Moreover, the more complete and efficient the combustion, the better the brake specific fuel consump-tion or mileage and the less the generation and emission of undesirable exhaust emissions.
Conventional injectors of the type disclosed in the above-mentioned Kirsch patent develop a spray by forcin~ fluid between a closely toleranced needle and its single sur-rounding closely-toleranced annular orifice, and the resulting drop sizes comprising such spray are of varied sizes and distributions depending on the actual dimensions of the annular orifice. Moreover, while a fuel injector using a plurality of circular apertures through a thick plate is disclosed in the U.S. patent to Harper, Jr.
This is a divisional of copending Canadian Patent Application Serial No. 273,500 filed on March 8, 1977.
This application is related to commonly-assigned Canadian Applica-tion Serial NoO 273,~6~, filed March 8, 1977 by Bode and Kiwior, entitled "Fuel sreak~up Disc for Injec-tion Valve".
Description of Prior Art Conventional fuel injection valves, such as of the type disclosed in the U.S. patent to Kirsch 3,R28,247 issued June 25, 1973, comprise one of the most expensive components of fuel injection systems in current mass production for passenger vehicles. Such conventional injectors incur such comparatively high costs because most of the structural elements effecting fuel breakup, fuel spray angle, fuel metering, and flow on/off valving are made to extremely close tolerances. Meeting these tolerances requires specialized lapping by a tool that cannot be used again for final lapping, and the resulting parts are custom rather than randomly mated. Even then such conventional fuel injec-tion valves do not normally breakup the fuel into controllably uniformly small particles and thereby limit the attainment of both maximum fuel economy and minimum formation of undesirable emissions.
Moreover, comprising extremely-narrow and closely-toleranced fuel meteriny and breakup paths, such conven-tion~l valves are susceptible to the deleterious effects of contamination passing the inlet filters of the injectors or back flowing from engine inlet passages into the injector outlet sec-tions.
It is therefore desirable -to reduce the cos-t of fuel . - - 1 -sb/`~
injection va~ves by avoiding -the conven-tional lapping and redressincJ, cus-tom hand ma-ting, and generally tight tolerancing all over.
A prlmary factor imposing harsh tolerancing requirements on such conventional fuel injection valves is the use of different elements of just one part, a reciprocating pintle-type needle-valve member, to perform the breakup, metering, and valviny functions. Each such different element must be closely concentric not only with the other elements of the same part but also with each of the surrounding structures cooperating with such elements.
The present invention recognizes that at least the close concentricity tolerances could be substantially relaxed and in turn other gross cost savings obtained by effecting the on/off valving function by a structure substantially separa-te from that effecting the fuel break-up function and the metering function. More specifically, recognizing that a circular seating edge need not be closely concentric with the metering orifice, the inven-tion allows the use of no less than three cost saving processes:
1) the conventional loose-concen-tricity low-cost "ballizing"
process of forcing a final diameter precision ball through an initially undersized aperture to repeatedly provide highly finished uniform orifices; 2) the conventional loose-concentricity low-cost "coining" process of forcing a precision ball against a softer conical surface to repeatably provide a circular non-leaking sea-ting edge;
and 3) the conven-tional loose-tolerance ball valve head and oversized ball seat technique to repeatably effect the on/off valving. Thus, even though ~he U.S. patents to Mattson 1,360,558 issued Novembcr 30, 1920 and Seccombe sb/~ ~
~,5~7,269 issued June 2~, 1971 sugges-ts -the use oE
ballizing, even though the paten-t to Carlson 3,400,~40 issued September 10, 1968 sugges-ts a ~uel injection valve having a ball seat coined by a slightly larger ball, and even though the patent to Malec 3,490,701 issued April 22, 1968 suggests the use of a stem-mounted ball valve, such prior art not withstanding fuel injection valves are not known to have heretofore used any com-bination of a ballized metering orifice, with a coined valve seat, or a stem-moun-ted ball valve head, perhaps because o~ the severe concentricity requirements previously thought to be essential.
As indicated above, a primary function of a fuel injection valve is to break up a metered quantity of fuel into combustible particles. Generally, the smaller the fuel droplets, the more readily they vaporize for combustion and the more completely they burn. Moreover, the more complete and efficient the combustion, the better the brake specific fuel consump-tion or mileage and the less the generation and emission of undesirable exhaust emissions.
Conventional injectors of the type disclosed in the above-mentioned Kirsch patent develop a spray by forcin~ fluid between a closely toleranced needle and its single sur-rounding closely-toleranced annular orifice, and the resulting drop sizes comprising such spray are of varied sizes and distributions depending on the actual dimensions of the annular orifice. Moreover, while a fuel injector using a plurality of circular apertures through a thick plate is disclosed in the U.S. patent to Harper, Jr.
2,382,151 issued August 14, 1945, such circular apertures generate a generally pear-shaped solid cloud of fuel particles rather -than control the size or variation thereof sb/`~`
of the par-ticles. Moreover, circular holes o~ the requisi-te smallness are difficul-t -to fabricate repeatably even by etchiny. The analysis by Raylei~h in his "On the Capillary Pherlomena of Jets" (Proceedings of the Royal Society, XXIX pp 71-97, 1879, Rayleiyh, Scien-tifie Papers, Vol. 1, Dover Publications, 1964) is therefore also of interest to the present invention. There Rayleigh noted that non-circul.ar orifi.ces through thin plates produced flat broad thin liquid sheets of fluid. More recent analyses, such as by Keller and Koldner in the Journal of Applied Physics Vol.25 pp 918-21 (1954), show that thin sheets produce small droplets. However, it was not appreciated until recognized by the present .
invention that non-circular slots of the requisite small width could be etched more precisely than circular apertures with the result that the thin-plate-non-circular-slot thin-liquid-sheet small-droplet theory is not known to have heretofore been applied to ~uel injection valves. It is therefore desirable to improve fuel economy while at the same time reducing undesirable emissions by sb/
breaking up the metered fuel first into thin sheets and then into uniformly small fuel droplets. Conventional injection valves of the type noted above ~o l;ttle if anything to shape the envelope of the spray emitted from the annular orifice. This results in a wide angle spray that wets the sides of $ tne intake Passages so as to enter the combuskion chamber in an unevenly rich ; and lean distribution. The present invention recognizes that such wetting and uneven distribution ~ay be reduced by providing a spray-envelope~shaping nozzle as a part of the injector immediately downstream of the Fuel breakup disc.
The pressure drop across the fuel breakup means of a conventional fuel injection valve is another factor requiring very tight tolerancing of not only the metering or;fice but also the breakup apertures. Since the ; precision of the quantity of fuel injected on each injection pu1se is dependent on having a known flow rate while the inj~ection valve is op~n and since a known flow reqllires having a known pressure clrop across a known flow area, the area of any part of the flow path across which there is any si~nifican-t pressure drop must be known and therefore closely controlled.
The present invention therefore further recognizes that the size tolerances on the fuel breakup means could be relaxed by ef~ectins the breakllp function by a structure substantially separate From that effectin9 the metering Function ancl by then desiynin9 the Fuel breakup means so as to have a minimuln pressure drop thereacross. In otherworcls, the present invention recoynizes the desirability of providing fuel breakup nleans havin~ a sufFicient flo~l area and minimal axial thickness so as to not generate any pressure drop signifi-cant to Fu l flow accuracy. In this way the ^tolerances on the non~circularbreakup apertures could be determined, nok so as to effect a requisite pressure drop by means of a precisely known flow area therethrollgh, but rather to effect the renuisite drop size, the tolerances on the breakup apertures ~LC~ 3 4 being looser than those on a metering orifice. Moreover, the tolerances on the breakup apertures could then be held by the low co$t etching throu~h thin plates.
Convent;onal fuel injection valves introduce an undes;rable, and often vehicle disabling, "hot start" problem upon restarting or attempting to restart an overly hot engine before it has had sufficient time to cool do~,~n. More specifically, during the comparatively short time bet~een shutting down an engine in an overly hot environment and attempting to res-tart the engine, all the components under the hood exp~rience a ".hot soak" as the overly hot enyine conducts, convects, and radiates heat to the auxiliary componen~s. In the case of the ~uel injection valves, the temperatures thereof are so elevated compared to the temperatures associated with normal operation that the fuel is substantially vaporized before reaching the valving and metering elements. To the extent that the ., fuel is vapori~ed prior to bein9 metered, less liquid fuel is expelled : . .
from the injector during a given injection interval than is expelle~ under .nor~al operating conditions when the fuel is substantially .1iquid. Con-sequently~ to the.extent that more vaporized than liquid Fuel is injected into the inlet passa~es of the engine, a substantially leaner than desired 2q mixture is injected. Such leaner mixture is often insuFFicient to permitprnper i~nition, preventin9 i~lnition under the wor.~t cases and other~lise ef~ectin~ s~umbling to rough ignition under less severe cases as the mixtures richen up to the desired air-fuel ratio. The duration oF such undesirable lean mixture perForn1ance varies primarily with the difference between the hot soak and normal operat.-ing temperatu.re and the rate at which the hot soak thermal energy is removed From the injector.
~6--.
o~
To avoid such "hot restart" Droblems, it is desirable to reduce the problem-causin~ conduction, convection, and radiat;on o-f heat from the engine to the injectors and then to eliminate whatever hot soak energy is transfèred thereto as fast as possible upon hot restarting. More speciFi-cally, it is desirable to minimize the initial conduction oF hot soak energyto the injectors by minimizing the surface contact area between the engine and the injectors and by minimizill~ convection and radiation by increasing the air space between the exterior of the enyine and the exterior oF the in~ector. Furthermore, to reduce the time required to remove whatever heat has been transfered to the injectors, it is desirable to reduce the cross- .
sectional area oF the injectors so as to increase the air space between the engine and injector, to reduce the storect hot soak ener9y that must subse~
quently be removed, and to other~lise maximize the rate that heat is trans-ferred from the body oF the injectors.
In solving this problem, the present inventinn recognizes that smoothly-flowiny normally-cooler fuel has a higher coefficient of heat transfer than turbu.lently flowing fuel and, not beincJ turbulent, can be metered more precisely. In this re~ard, the present invention recogni~es that it is desirable to incluce a substantially smooth flo~Y and to clo so by a substantially straight and llnimpeded central fl~el Plow innlecliatel;y upstream of the valve and orifice rather than the prior art sicle-ported and peripherally-chanelled fuel flow of the types producecl by tlle valves disclosed in the above mentioned patents.
A further primary function effected by a fuel injection valve is to repeatably and rapidly actuate the valve by the electromagnetic inter-action between the flux produced by a fixed coil acting on a moYable pl~lncgeror armature connected to the valve head. Conventionally, the actuator is electromagnetically opened to a position determined by the abutlllent of a shoulder protruding From the actuator,against suitable abutlnent on the valve body such abutment norn1ally being in the form oF a "C" ~Yasher. Upon ::de-energizat;on of the coil the actuator is sprin~ closed to a closed posi-tion determined by seating oF the valve head on the valve ~eat. To effect as rapid a response as possible with the establishment oF a threshold l~vel oF magnetomotive force by the coil, the actuator is made as light as possible and the magnetic lock up between the fixed and mavable elements is prevented by ma;nta;ning min-mum ma~netic air gaps for the magnetic flux. ~n addition to permitting a fa$ter opening response, a light actuator permits the use of a ~leaker closing spring to effect softer closing and thereby a1so reducing the pounding wear bet~Yeen the valve head and valve seat.
The outer surFace of a conventional actuator and the matin~ inner surface of a conventional actuator housing are therefore heat treated and closely toleranced as ~o diameter and squareness so as to pro~Jide a durable slidin9 metal-to-metal contact, Such close tolerancin~ is required: 1) to enable the actuator to precisely pilot and center the valve head on the valve seat;
23 to precisely pilot and center the.pintle needle in the metering orifice~
and 3) to maintain the minjmum magnetic air ~aps axially between the r~ar encl oF the armature and the Front of the Fuel inlet tube and also radially between the outqr diameter of the armatllre ancl the inner diameter oF the matin9 valve bocly. It is clesira~le to avoicl heat treatnlent and relax ~h~se tolerances especial'!y s1nce they must othenYise be ma;ntained on substant;ally blind and very small actuator housing bores.
The present invention reco~nizes that an actuator which is tubular in form enhances such lightness in adclition to also inducing a smoothing better-coolijn~-and-meterin~ eFFect on the central flow therethrough. Moreover, ~06~09~
' .
, the present invention further reco~nizes that, rather than providing a sliding metal-to-metal contact between the actuator and its housing, it is more desirable to do the opposite by providiny an ample positive clearance therebetween to allow the resulting surrounding pressurized fluid fuel to su-fficiently center the actua-tor to effect the necessary sea-ting and to - maintain the minimum air gaps. Also, lower actuation energy is requiredwhen the actuator slides on a fluid rather than me-tal surface, also per mitting a weaker closing spring resulting in lower closing impact and longer actuator life. The present invention further recognizes that a pos itive clearance between the actuator and its housing aiso enables the actuator to provide some of the flexing action otherwise required oP the stem ~o properly seat the stem-mounted ball valve head on the valve seat.
More specifically, the length of the actuator telescoping the stern and free to move in the positive clearance acts as extension oF the stem and thereby r~duces the life limitln~ flex stresses that would otherwise be imposed thereon.
A further cost imposing feature of conventional fuel injec-tion valves heretoFore used with commercial passen~er vehicle fue1 injection systems is that the electromagnetically responsive armature is mo~lnted on a non-magnetic actuator. Not only is the non ma~netic Inaterial more costly perpouncl by half again as much as the md9netic material, bilt the s~para~e armature and actuator parts require close tolerance machining oF the requisite mating concentric bores in the armature and receiving surfaces on the actuator followed by the close tolerance axial positionin~ of the armature on the actuator. The rnain reason requiring such separate materials apparently was the previous belief that, unless the actuator was oF non-magnetic material, tne motion limiting stop shoulder thereoF would efFect a magnetic lock-up with the magnetic return path of the valve body and would there~y unacceptably slow the opening and clos;n9 t;mes of the injector.
_9 The present invention recognizes that any ma~netic lock-up bet~leen the actuator shoulder and valve body is second order compa~ed to that possible between cylinclrical outer surface of the armature and valve body because the latter prov;des not only the shorter flux return path inherently efFected by magnetic flux but also provides more matin~ gap sur-face. The present further recognizes that, rather than suffering the cost and other penalties of provicling an armature and actuator of difFerent materials, it is fea$ible and more clesirable to do the opposite by making not just the armature and actuator but also the actuator housing out of the same material.
By doing so avoids the differential thermal expansion rates hereto-Fore resultin~ from different coefficients o~ expansion. Also avoitled is the growth of crystals in the gaps normally resulting from the galvanic corrosion reaction conventianally occuring between the dissimilar materials of the actua-tor and its housing, such similar material thereby further reduc;ng the friction therebetween while increasing valve life by avoiding catas trophic galvanic-growth-induced sei~ure of the actuator to its housing.
Yet another problem heretofore experienced with electromacgneti-cally actuated fuel injection valves is that the welded connections between the end oF coil wire and the output te ~I;nal of the injector oFten break when th~ output terminals are wig~led on the assembly, connector molclin~
testin~, shipping, or sub~sequent encJine mountirl9 ancl connection oP the injector. Conventional fuel in~ection valves oF the type noted above attempt to avoid these problems by the use of L-shaped terminals that enter the in-jector axially ancl then, make an "L" turn in opposing circumPerential direc-~5 tions so that the inside of coil bobbin and/or inlet connector flange prevents the terrninals from being rnoved axially. Such terminals of course are not stampecl out Prom lo~er cost straight r;bbon stock of term;nal wi~th. It f is -therefore desirable to provicle a straight narrow terminal that can be securely anchored within the bobbin.
., . I .
.
It is -therefore a primary object to provlde a new and useful fuel injection valve havin~ a cost substantially less than that of conventional fuel injection valves mass produced vehicle fuel injection systems.
It is a further object of the present invention to provide a fuel injection valve comprisiny a coil bobbin and terminals for electrical connection with the ends of the coil wherein the coil bobbin comprises an axially extending terminal-insulating-post having a dimple locking wall at one end of a welding aperture over a terminal slot and the terminal comprises a thin axially extending section having a dimple across sub-stantially the entire width thereof, the dimple being retained by the dimple locking wall.
1'he present invention resides in a fuel inlet assembly for a fuel injection valve having a fuel inlet connector comprising an inlet tube portion se~arated from an outlet tube portion by a radially extending flange portion, the flange portion having at least one terminal insulating post aperture therethrou~h between first and second flange sides. There is provided a coil and terminal assembly including a coil bobbin and a thin terminal. The coil bobhin has :Eirst and second radially extending flanges separated by an axially extendincJ
~-entral portion positioned on the outlet tube portion, one of the bobbin Elanges including a terminal insulating post extending axially therefrom throuyh the aper-ture.
The terminal insulating post has Eirst and second ends separated by a thin slot extending the axial length of the post, the first end terminating at the one bobbin flange and the second end terminating outboard the . .
. - 11 -~ sb/
~69(~
second inle-t conncctor flange side, the terminal post further including an oblong opening having a floor deEined by the thin slot and a dimple :locking wall extending radially outwards intermediate the first and second ;~
terminal post ends. The thin terminal has a narrow length portion received in the thin slot, the n~rrow leng-th portion having a di.mple across substan-tially the entire width thereo:E, the dimple beiny engaged by the dimple lockiny wall to restrain the thin -terminal from axial movement in the thin slot.
FIGURES
FIGURr~ 1 is an end vi.ew of a preferred embodiment of a fuel injection valve constructed in accordance with the present invention:
FIGURE 2 is a view of the fuel i.njection valve of Fiyure 1 taken along partially rotated view 2-2 thereof;
; FIGUP~E 3 is a view of the fuel :i.njector valve o:E Fiyure 2 taken alony view 3-3 thereof showing a fuel ~ breakup disc etch~d with thi.n-slot apertures therethrough .~ 20 in accordance wi-th a preferred configuration of the present invention;
FIGUR~ 3a, which appears on the same sheet as E'iyure 5, .is a plan view of an alternat.ive configuratlo of slots etched throuyh a thin breakup clisc;
FIGUR~' ~ is an en:Laryed and exaygerated view oE
the valve seat and o.rifice portion of the fuel injection valve of Figure l;
F:CGURF 5 is a plan view of a fuel injection valve of ~igure 2 taken aloncJ view 5-5 thereof so as to show :. 3~ the combination of an elec-trical terminal with an insulator post;
FIGURE 6a, 6b and 6c shows and compares the bra~e specific fuel consumptio~ (BSFC) and emission results a-t .
~ .2 -; sb/`
.. . . .. .. . . .
- ~69~
di~Eeren-t enc~ine loads and speeds for different air fuel ratios of the fuel injection valve of -the present invention (solid lines) and of -the prior ar-t (dashed lines), Fig~lre 6c appeaxs on the same she~t as Figure 5;
FIGURE 7 .is a sectional view of a conventional fuel injec-tion valve.
. With reference now to the conventional fuel injec-tion valve shown in Ficture 7, there is shown a pintle-type fuel injec-tion valve comprising a valve body A and a valve needle B that has its tip -forced tightly against a valve seat C in the valve body by a compression coil spring D, thereby tiyhtly closing the valve opening E. The needle valve B is provided wi.th an armature F of material which conduc-ts the magnetic flux generated by a mayne-tic coil G. The delivery o:E
exciti.ng current from a suitab:Le source to the magnetic coil will. cause the armature ~' to move in an axially direction (towards the riyht in Figure 7) until a projection Il on -the valve needl.e B abuts against ~ 20 a stop ~ in the valve body~ The valve needle ~ is centered '~ wi-thin a hore K of valve body A by a cylindrical first land L spaced axial.l.y ups-tream on valve needle B Erom plurali-ty of axially extendinct lands M pxojec-tincJ
xad:ially outwards from the valve needle B and provicliny corresponding plurality of axial:ly extending peripherical passages therebetween. When -the valve C is opened, fuel under sui.-table pressure is communicatecl by a suitable condu.i.-t N to a fuel i.nlet end P of the injector and flows centrally therethrough and throuyh a tubular core element ; 30 Q to the -tubular rear end of valve needle B. The cen-tral bore R of valve needle B extends axially inwards from the core end of -the valve needle B -to a point intermediate ' .
~-.;;.~, - 13 -sb/~
~` ~069~0~
lands I, and M and there passes r~dially outwards through a pair of suitable radial apertures S. The flow of fuel proceeds ~xially therefrom abou-t valve need].e B past land M and valve seat C exiting in the annu].us defined between valve opening E and needle T, the dimensions o~ the annulus between the needle T and opening E determining the size, distribution, and cone angle of the droplets comprising the fuel spray.
DETAILED DESCRIPTION OF INVENTION
` 10 Turning now to Figures 1 and 2, there is shown a fuel injection valve 10 adapted to be positioned by a resilient rubber grommet 12 and a gas back-flow shield cap 14 in a counterbore 16 suitably provided in an intake ~ passage 18 continuously or intermittently communicated with one or more combust:ion chambers (not shown) o:E an internal combustion engine 20. Fuel injection valve 10 is further adapted to be communicated with, and biased towards counterbore 16 by a fuel conduit means 22 such -:
as of the type disclosed in tlle commonly-assigned United States patent to Wertheimer et al 3,776,209, entitled "Fuel Injector ~anifold and Mounting Arrangement", issued December 4, 1973. At its injector end conduit means 22 . comprises a circular groove or counterbore 2~ ~or receiving an elasti~ ~nd deformable circ~llar seal 26. At its pump end, conduit means 22 is communicated with suitable ~uel pump means 28 adapted when energized to pump ~uel 30 at a suitable p.redetermined pressure such as 39 psig from a conventional fuel tank 32 via a suitable fuel line 3~.
Fuel injection valve 10 is fur-ther adapted to be electrically communicat~d by means of conduc-tors 36 and 37 and an electrical connector (now shown) with an electronic computing unit (ECU 38) comprising circuits ~ ' . .
sb/`~
: : .
' 3L069~04 o~ the type disclose~ in commonly-assigned United Sta-tes patents to Reddy 3,734,068, entitled "Fuel Injec-tion Control System," issued May 22, 1973, 3,725,67~ to Reddy, issued ~pril 3, 1973, 3,919,9~1 issued November 18, 1975.
Electronic computing unit 38 is suitably coupled electri- ~' cally and mechanically with engine 20 to receive information ; therefrom in the form of engine speed (RPM) signals 40, ~ temperature signals 42, and manifold air pressure signals : 44.
Starting at its outlet or left end as viewed with respect to Figure 2 and working clockwise towards its inlet or right end, fuel injection valve 10 comprises conical spray forming means in the form of an outlet nozzle 50, uniform fuel breakup means in the form of a thin break-up disc 60, metering means and valve seat means i.n the form of a valve seat and orifice means 70, a tubular actuator housing means 90, tubular valve body means 120, actuator means 1~0, a molded electrical connector plug assembly ; 170, and inlet connector means 190, and inlet filter means220, and a bobbin and terminal assembly means 2~0.
Nozzle 50 Nozzle 50 comprises a conical surface 52 there-through diverginy Erom an a~ial inlet end radial surface 5 to an outlet end radial surface 56, and 18 conical angle of conical surface 52 being selected to tailor the spray envelop of the fuel droplets ejected by injector 10 to be compatible with a particular configuration of inlet passage 18 and/or the combustion chamber intake valves ~not shown) of internal combustion engine 20. The circular pheriphery of noz~le 50 is positioned cen-trally in an outlet bore 92 of valve body 90 and comprises intermediate inlet end surface 54 and outlet end surface 56 suitable hold-in means in the form of a circular external shoulder 58 ~ 15 -sb/~
.
~L0~9~
.
for cooperating ~lith suitable valve bo~ly hold-in means in the forrn oF a raclially inwardly swayeable lip 94 to èFfectively secure no~zle 50,spray disc 60, and valve seat and oriFice 70 within housing outlet bore 92 a~ainst radial seat 96 counterbored at the inboard end thereof.
Fuel Breakup Disc 60 As rnay be better understood in conjunction with Figure 3, fuel b,eakup disc 60 comprises a thin (0.05 mm) sheet having chemically etched tilerethrough Four-slot groups 61a-d, 62a-d, 63a-d, 64a-d, 65a-d~ and 66 a-d grollped by sectors and positioned radially outboard o-f a seventh equi-angularly-spaced three-slot group 67a, 67b, and 67c. One arcuate . end of each slot in groups 61-66 commences at an arcuate position rotated 5 clockwise when viewed with respect to Fi~ure 3 From the starting arcuate encl of the next radially inboard slot of the same group, and the other end of each slot in a group 61 to 66 terminates to include 6 more than the -15 nex-t radially inboard slot o-f the saml group. In this m~nner, the arcuately ,. shortest slot in group 61-66 is 30 and the longest, being the fourth slot and thereFore having ~4 greater de~rees of inclusion, is 48. Each of the three slots 67a-c include an angle of 60.
Each slot has a typical width oP 0.05-0.07 mm ancl has an illner raclius spaced from the inner rarlius of the next ad~iacent radially outboarcl slot of 0.1~3 to 0.25 mnl. Th~ 0.20-0.25 n~n radial spacing between the outer radial edge of one slot and the inner radial edge of the next rad;al outboard slot is selected to prevent congealing of shee~s of fuel developed byacljacenl: slots and a1so to permit efficient chemical etching thereof. The o.n5-0.07 mm radial slot thickness has been founcl to permit the breakup of fuel into uniformly smal l droplets oF less than 100 rnicrons in diameter ith a standard deviation of less than 100 microns and may be satisfactorily ~leveloped with conventional etching or possibly stamping processes.
'' . .
- 1 6 - ~
', 1.
.
~06~00~
The total number of slots, here 27, their radial ~/idths, and their arcuate len~ths are selected so that, for the 0.05 nlm typical thickness oF
the disc 60, and a typical fuel pressure of 39 psig, the total flow area through the slots is more than 150% of the flow area of orifice 76 valve seat and orifice means 70. With such dimensions and fuel pressure, substan-- tially the entire 39 psig is dropped across the metering orifice 76 so that the flow area of the metering orifice determines the magnitude of the Flow rate.
As sho~n in expanded detail in Fi9ure 4, to provide a suitable clamping surface between nozzle surface 54 and a radial surface 7~ at the outlet end of valve seat and metering orifice 70, fuel breakup disc 60 comprises an uninterrupted radial surFace 68 radially outboard oF the outer most arcuate slots 61a, 62a, 63a, 64a, 65a, and 66a. Moreover, so that unimpeded spray may be developed throu~h these outer slots, the inner dia~
meter oF the uninterrupted surface 68 is somewhat less than the inner dia-meter of either divergent nozzle inlet surFace 52 at its inlet side 54 or ; the outlet diameter of the divergent conical outlet surface 72 o-f valve seat and orifice 70.
While shown as a structure separate from that of actuator housing 90, nozzle 50 and valve seat and orifice 70 could both be macle as a part ; tllereof, A suitable disc receivin9 groove could then be un~l~r~llt radially between nozzle 50 and v~lve seat and oriFice 70 to allow thin fuel breakup disc 60 to be snapped into the undercut groove by suitably spring shapin~
the disc into a conical bevel form while pressing it uniFormly and evenly into nozzle 50 from its outlet end 56.
While a presently preferred embodinlent of the configuration of fue1 breakup disc 60 is shown in Figl~re 3, an alternate -Forrn thereof is shownin Fi~ure 3a wherein the arcuate lengths of the various radially adjo;ning arcuate slots are the satne as ttle arcuate lengths clescribed for slots of ~(~69~
.
sirnilar raciius with respect to and shown in Figure 3 the only signi~icant difference being that the slots are all equi-anyularly spaced ~ith respect : to other slots of the same racl;us rather than bein~ grouped by sector.
Valve Seat and Orifice 70 As may be better unders~ood in conjunction with the expanded view thereof oF Figure 4 valve seat and orifice 70 is annular about valve axis x-x and comprises a smoothly-finished substantially-centrally-located .
circular orifice 76 hav;n~ a 0.25 to 0.41 ~m axial-length less than its 0.4 mm up to 1.6 mm radial diameter. Orifice 76 communicates a divergent generally conical outlet surface 72 with a convergent 9enerally conical .
90 inlet surface 78 terminating at its outer diameter in an annular radial seatin9 surFace 80 the outer diameter of conicai surface 7~ being substantially the same as or mer~ing smoothly with an actuator housin~
~; ~ annulus bore 98 in actuator housin9 90. Intermediate its inlet and outlet seating surfaces 80 and 74 r~spectively valve seat and orifice 70 comprises a pheripheral cylindrical groove $2 containing an O ring ~4 suitably com-pressed aga;nst outlet bore 92 of actuator housin~ 90 to provide a seal thereat. Intermediate inlet seating surface ~0 and metering oriFice 76 the generally conical convergin~ inlets surFace 78 co~prises a sc.~mi-? spherical ball valve seat ~6 terminating at its outer cord ~7 in a finish~d circular seating edge 88 loosely conccntric with mPtering orifice 76.
Metering orifice 76 is fabricated by First drillin~ or other~ise roughly forming an initially-ùndersized aperture through valve seat and orifice 70 :.
and then forcing or "ballizing " a Finished precision bail of final orifice 25 diameter therethrough from the inlet side to the outlet sicle. Thereaftersemi-spherical ball valve seat 86 and circular valve seat eclge $8 are formed in a one step prncess of forcing o~ "coinin~" a Finishecl precision ball 89 of a diameter slightly greater than a ball valve 14~ of actuator 140 into the then unheat-~reated conical surface 7$. ThereaFter~ valve sea-t arld orifice 70is mechanically .deburred and pacivated anci heat treated. ~ .
, 1~ .
~0690ia 4 ':
Valve seat and oriFice 70 is suitably sized as to metering : diameters inlet surfaces and outlet surFaces etc. for each different engine application and can be made either as a separate element as shown . or as an integral part of actuator housing 90 thereby in one step saving at least the cost of an 0 ring 84 in addition to machining such surfaces as the outer diameter 91 of the valve seat and orifice 70 as well as groove 82 therein and inlet seating edge 80 thereof as well as outlet bore 92 ~nd counterbore seat 96 of actuator housing 90.
Actuator Housin~cJ gO
10 ... As has already been described with respect to outlet nozzle 50 .l and valve seat ancl oriFice 70 actuator housing.90 is generally tubular in form about valve axis x-x comprising an outlet bore 92 defining an outlet cavity 93 separated by a counterbored seat 96 From an actuator bore 98 defining an actuator cavity 127 and terminated at its axially-outboard - 15. outlet end by nozzle hold in means in the ~orm o-F radially inl~ardly s~ageable . lip 94. At its axially-opposite outboard inlet end actllltor housing 90 conlprises an axially extencling lip 100 cleFinecl by a collnterbored cavity 102; and tetmin~ted in a raclial abllting surFace ln~. Upon assembly ~Yith valve body 120~ radial abuting surFace 104 engages a first radial surFace 106 . 20 of a C washer 108 so as to secllrely posit.ion the other axial side 11~
ther~oF ~gainst an annular seat 122 counterbored into an annular hub 12~.
~ ~lub 12~ is located intermediate and actuator annulus or bore 126 bored into .. one end of the valve body 120 to thereby de-Fine an ac-tu~tor cavity 127 and inlet and coil asselnbly bore 12~ bored in-to ~he other encl ~lereof to thereby ; 25 define a coil and inlet assembly cavity 129.
, ~
~L()6~C~C74 Intermediate its radially swageable lip 9~ and axial lip 100, the periphery of actuator housing 90 comprises a shield cap peripheral surface 112 and a larger d;ameter valve body peripheral surface 114 .-separated by an undercut groove 116 and radial shoulder 117. Shield cap surface 112 is selected to provide a snug -Fit with the internal cylindrical surface 15 of shield cap 1~, and valve body peripheral surface 114 i5 selected to provide a snug fit with actuator housing bore 126 of valve body 120. Radial shoulder 117 comprises hold-in means cooperatin~ with mating hold-in means in the form of a radially inwardly swageable lip 130 of valve body 120 to urge actuator housing 90 and C washer 108 against counter-bored seat 122.
Suitable seal means in the form of an O rin~ 118 is captured in an O ring groove 119 on the periphery oF actuator housing 90 and suitably .~ . seals periphery 11~ thereof against actuator housing bnre 126 of valve body .
120.
; ~ VALVE BODY 120 As has already been described with respect to the actuator housing 90, valve body 120 is tubular about valve axis x-x and compresses there-through an actuator housing bore 126 separated by an annular hub 12~ From a .. . .
coil and inlet bore 128. The outboard outlet elld of actuator housing bore 126 is terminated by lip 130 that is radially swacleable inward~y to e~gage raclial shoulder 117 of annular lmdercut gronve 116 of actuator housing 90.
Annular hub 124 comprises an axially extending cylindrical surface 132 that together with an axially extending cylintlrical surface 1~2 of actuator 1~0 2S defines a predetermined m;nimum axial gaP 1~3 o~ about 0.23 to ~.38 mm.
At its inlet end, valve body inlet bore 128 compr;ses a counterbore 13~ --- 20 -- ~
69~
axially intcrmediate an annular raiclal seat 136 and a terminating radially in~ardly s~ageable lip 138. Ilhen swaged inwardly lip 13g that holds a flan~e 192 of inlet connector 190 against counterbDrecl seat 136 to position flange 192 both radially and axially with respect to valve body 120.
Actuator 140 comprises a one piece tubular armature 144 a flexible stem 146 and a ball valve 148 all located either about or along valve axis x-x. The tubular armature 144 in turn cornprises an armature element 150 separated from a guide element 154 by a radially outwardly extending shoulder element 152. A free end 147 of thin flexible stem 1~6 is ~elded to ball valve 148 ~\ fixed end of the stem 146 is centrally positioned in a small hore 149 through the rear quarter of armature element 150 and is suitably affixed ax1ally outboarcl thereof such as by brazin~
wel(ling or staking. Telescoping a substantial length of stem 1~6 is a celltral passage 156 opening at its outlet end into actuator bore 9~ towards ball valve 148 ancl terminating at its inboard end at bore 149. The internal diameter of central passage 156 is substantially greater than the ex-ternal diameter o~ flexible stem 146 so as ~o provide a free flowincJ 1.60 to 1.79 mm total clearance therebetween in which stem 146 may flex freely about its end fixed in bore 1~9 as ball valve head 148 seats in its slightly oversizecl ball valve seat 86 in comirlcJ to a closed position at circular ~dge 88 thereoP~Along the periphery 142 of armature element 150 are a pair of d-iametrically opposed slots 158 cut radially ~80 apart from the rear of armature elelnent 150 to a cliameter slightly less than tha~ the internal diameter of central passacJe 156 so as to provicle a firs~ free flowing 0.49 x 10.16 rnm passage 160 between central passage 156 and each axially extending peripheral slot 1~8 and a second free flowing 0.49 x 2.47 mm passage 162 through the ra(lial-exterlding end surface 164 o~ armature element 150.
.'' , '' . .
~Lof ;~90~4 ';.
Arnlature element passa~es 160 and 162 thereby freely con~unicate central passage 156 of actuator 140 with a central outlet bore 194 of inlet connec-tor 190 so as to provide an ample passa~e for fluid flow therebetween.
The periphery of armature tJuide element 154 comprises a cylindrical surface 166 of external diameter selected with respect to the internal . diameter of actuator bore 98 of actuator housing to ef-Fect a loose fit of about O.Q07 to 0.035 mm total positive clearance therebetween. The 8.1 mm ~IxiallY
-~ lerlgth of guide periphery 166 is selected to be sli~htly greater than twice the 4 mm diameter thereo-F. This positive clearance/loose fit ~etween the external periphery 166 of t~uide element 154 and the internal bore 98 of actuator housing 90 allows pressurized fuel to be forced between and thereby roucJhly center actuator 140 in both actuator housing bore 98 valve botly bore 132 so that with the actuator 140 ;n its open position defined whcn . raclial surface 153 of shoulder element 152 abuts radial surFace 106 of washer 108 the radial air gap 143 between the armature periphery 142 and hub axial surFace 132 is not less than about 0.22 mm and the axially air gap 168 bet~Jeen arrnature end surface 164 and a radial end surFace 196 oF
inlet connector 190 is not less than 0.06 mm.
MOLUED P~UG 170 Molded plug 170 comprises a rectanglllarly-shapecl connector recepticle portion 172 protrudintJ Prom an annular hllb portioll 174 ~t an an~le of about 60 with respect to the longitudinal actuation axis x-x oF
fuel injector 1~. Hu~ portion 174 ~rotrudes axiall.y fronl ~ Flange port-~on 176 encompassin~l and sealintJ the valve boflv lip 138 as l~ell as inlet connector ~ldnge 192 antl terminal insulator posts 2~2 and 244 oF coil arl(l bobbin assenbly 240. Hub portion 174 and flan~e ~portion 17~ are canivated axially in tgroove 198 of inlet connector 190 bet~Jeen a side 286 of inlet connector flange 192 and a shoulder 205 intermediate groove 198 and a shoulder 206.
Annular hub 174 comprises a pair oF oppositely clisposecl s~ake holes 17~ and . . .
9~4 ... .
1~0 extending radially therethrough to allow the ;nsertion o-F a stak;ng tool for the purpose of de~orming an annular sroove portlon 1~8 o-F inlet connec-tor 190 so as to position a sprin9 acljusting tube 200 in b~re 194 therenf.
Electrical recepticle portion 172 is terminated a~ its ou~.board end by a rectangular peripheral lip 182 t)ounding a rectangular tapered cavity 184 having a pair of inwardly tapered sides l~a and 186b clefining the long sides of the rectangular cavity 184 and telescopins so as to centrally position therebetween a pair oF electrical terminals 2~6 and 2~ protruding through hub portion 174 from terminal insulator posts 2~2 and 244 respectively.
Beveled downward into cavity 184 along a portion o-F tapered side 186b thereof is a inwardly-sloping down surface 187 having a ~air of remale semi-cylindri-cal key grooves ?88a and 188b formed therein. The long rectangular sides 186a and 186b and the short rectangular sides 189a and 189b of cavity 184 are tapered inwardly to provide a wedgin9 action against an electrical ; 15 connector (not shown~ when inserted -therein.
Inlet Connec-tor 190 Inlet connector 190 cotnpri$es a radial flange portion 192 inter-mediate an inlet tube portion 202 and an outlet tube portion 20~. FJan~e surface 286 comprises radially extending knurled identations 193 at the radiallyoutboard edges thereoF to lock flanye 176 of molcled plug 170 and also lip 13~ of valve body 120 against relative circumFerential motion about valve body axis x-x. The periphery of inlet tube portion 202 comprises the de-formable circular yroove 198 intermediate flange portion 192 and a circular raised shoulder 206. At its inlet end, inlet tube 202 comprises a recessed surface 208 terminated in a radially outward extending shoulder 210 for seatin~ 0 ring 26. Passing c~ntrally through inlet connector is a stepped-bore comprising an inlet bore 212 and the smaller outlet bore 194. Inlet bore ; 212 extends into inlet tube portion 202 a length sufficient to anl~ly enclose inlet filter assembly 220, and outlet bore 19~ passes throush the ren1ainder - 23 - ~ :
:, :
o~
oF inlet tube 202 as well as throu~h flange 192 and o~ltlet tube portion 204.
Outlet tube portion 202 terminates in the annular radial surface 196 wh;ch Forms one side of the axial air ~ap 16~ the other side oF which is formed by ter~inating radial end surface 164 of armature ele!nent 150.
Suitably positioned within outlet bore 19~ are the spring posit-- ioning tube 200 anci a helical sprin9 214. The outer cylindrical periphery of spring positionin~ tube 200 is knurled or othenYise suitably deformed so as to suitably lock against outlet bore 194 when annular srQove 198 is deformed . inwarcily by staking upon assembly throu~h molded plug apertures 178 and/or . 10 180. When stakecl, the axial position oF t~bular spring positioning tube : 200 within outlet bore lg4 is selected so that "~ith one end oF helical spring ; 214 positioned against an annular radial terminating shoulder 216 and the . . other end positioned against the radial end surFace 164 of actuator element j; 150, spring 214 imparts to actuator 140 the proper bias to efFect the . 15 desired opening and closing dynamics characteristics thereof. Moreover, to more carefully tailor the maynetic circuit provided by coil and bobbin assembly : 240 when energized, a pair oF thin slots 218a and 218b (not shown) are cut 180 apart on the periphery 219 at the outlet end of outlet tube portion 204, the axial slots 218 also further enhancing smooth flow oP Fuel into passacJes ZQ 158 of armature element 150 ~lhile also reducin~ the edd~ currents produced in inlet connector 190.
'. Inlet Filter Assembly 220 . .; .
.;j As described above with reFerence to the inlet connector 90, ~ . .
. inlet Filter assembly 220 is con~ained within inlet bore 212 oF inleL
connector 190. The inlet Filter assembly 220 forms a flat-end-shaped axially-'`'t extendin~ pocket formed by a pair oF screens 222 and 224 of about.325 mesh.
The screens 222 and 22~ are joinecl by suitably inte~rally molding their ~eri-phery into a common frame havin~ a pair of webs ~27 connecting a flat end 226 ~ith an annular collar 22~ formin~ an inlet opening at the mouth of inlet j~
~.... 30 connector 190. Annlllar collar 22~ is molded over the per.iphery of screens .~,. . .
,~- 222 and 22~ and is pressed fitted into inlet bore 212.
':
' ~ ' . .
;9~
The above described fuel injection valve is also disclosed and is claimed in above-identified parent application Serial number 273,500.
Bobbin and Coil ~ssembly 240 Bobbin and coil assembly 240 comprises a coil 250 of about 306 turns of magnetic wire wound on a spool like bobbin 252, coil 250 comprising a beginning inner end 254 and a terminating outer end 256 seen better in Figure 5. Spool 252 comprises an armature end radially extendiny flange portions 258 and a flange and radially extending flange portion 260, flange portion 258 and 260 being integral with but separated axially by a central axial portion 262 positioned along valve axis x-x within valve body cavity 129. The axially outboard sides of flanges 258 and 260 comprise respective annular lips 264 and 266 protruding axially therefrom. Lip 264 comprises - an external shoulder 268 cooperating with flange 258 to urge an 0 ring 270 outwardly against valve body bore 128, and lip 266 comprises an internal shoulder 272 cooperating with flange portion 260 to urge an 0 ring 274 of the same diameter as 0 ring 118 inwardly against periphery 219 of outlet tube portion 204.
At its axially outboard end annular lip 266 terminates in an annular radial surface 278 seated against a coil and spool side 280 of connector flange 192, and a small sector of flange 260 and lip 266 thereof compris~s the terminal insulating post 242 and 244 as also seen more clearly with respect to Figure 5. Terminal insulating posts 242 and 244 project axially through a pair of circular apertures 282 and 284 (not shown) provided through connector flange 192 and respectively receive terminals 246 and 248 inserted from the inlet connector side 286 .
sb/ ~ - 25 -6900~
of connector flange 192. ~he leng-th o:E each of the terminals 246 and 24~ comprises a narrow leng-th portion 288 separated by a neck 290 from a comparatively wicler length portion 292, narrow portion 288 having an upwardly protruding conical dimple 294 formed su.bstantially thereacross. Each of the terminals insulating post sb/
~9~4 comprises an arcuately narro~.l slot 296 passin9 axially therethrough and of a radial thic~ness substantially the same as the radial thickness of the narro~.~ portions 288 of terminals 242 and 244. Each of the terminal insu-lating post 242 and 244 comprises a respective rectan9ular weld and dimple opening 298 ancl 300 opening radially outwards ~rom a -floor 301 deFined by the radially inboard surface of each of the slots 298 and 300 and extending axially in~ards from a front wall 302 to a rear wall in the form of flange 260, front wall 302 rising radially above slot 296. The terminals 246 ancl 248 are assembled into terminal insulating posts 242 and 2~4 prior to the molding of molded plug 170 by softly forcing the narrow length portion 2~8 and dimple 294 of each terminal throu~h the terminal slot Z06 until a rear surface 304 of each terminal abuts a~ainst flange 260 at which point dimple 294 axially clears front wall 302 of each openin9 298 and 300 to be a~equately restrained from axial movement therein. After the terminals 2L~2 and 244 are thus securely inserted into slots 298 and 300 the beginning and terminating ends 254 and 256 respectively oF the coil 250 are positioned in radial slots 306 and 308 throu~h flange 260 and then suitably electrically connected to narrow.ternlinal portion 288 in opening 29g and 300 as by spot ~elding at a ~/el~ point 310 intermediate each dimple 294 and the flange 260.
Radial slot 306 further commurlicates with a down-slot 312 Formed on the coil side of flan~e 260 to ~)rovide a suitable wire protection pocket extenclinc~
radially from the outer cylindrical surface of central portion 262 to the opening floor 301 to provide a suitable pocket therebetween to protect the beginning end 254 of the coil wire 250 from abrasion while winding the re-2S rnainder of the coil therenf.
. ~ . - . . . . . . .
~69()04 , MATERIALS
As has been indicated above with respect to actuator 140, armature 144 thereo-f comprises an armature element 150, a shoulder element i52, and a guide element 154, all of which integral with each other since they are being macle from the same piece of bar-stock material. So that the exhibits the proper electrolnagnetic response to the field createcl by coil 250 upon energization thereof, armature 144 is made from a ferro magnetic ~aterial such as 182 FM provided by the Carpenter Steel Corporation or 18-2 FM
provided by Universal Cyclops Uniloy Corporation. Moreover, to afFord a uniform coefficient of thermal expansion with armature 144 while at the same time avoiding cell-growing galvanic action with certain dissinlilar materials, actuator housing 90 is also made froln the same ferro magnetic material. Thin fuel brea~ up disc 60 is made of AISI type L corrosion resistant steel, and the tubular valve body 120 and tubular inlet connector 190 are each made from fully annealed steel AISI 12Ll~. The molded pluy is made from nylon-glass fiber (30%-40%) type 6 nylon reinForced, such material when molded shrinking about the flange 138 of valve body 120 and axial groove 198 to provide a tight seal aga;nst one side oF connectoi . flange 192. Moreover, the overall outer diameter.of fuel injection valve 10 is made materially smaller than that of conventional ~uel injection valves oF the type shown in the Prior Art Figure and the outer envelop PR
of which is shown dotted in about the outer envelope of the ~uel injection valve 10 shown in Figure 2.
~;9()~4 SUBSTANT~ALLY LAMINAR CENTRAL FUEL FLO~
.. Fuel injection valve 10 is speciFically designed to effect a smooth flow of Fuel from the inlet bore 212 thereof to the ball valve head and seat 148 and 86 respectively. When Fuel injection valve 10 is connected .-~lith fuel rail 22 to receive fuel under a 39 psig pressure and ~hen coil 250 is energized to pull actuator 140 back until shoulder 153 abuts a(Jainst ~asher 108 fuel flows into the inlet bore 212 and is there Fjltered by fuel inlet filter assembly 220. ThereaFter the fuel proceeds centrally ` through the ample bore of spring adjusting tube 200 and Flows axially into end openings 162 oF axially slots 158 o-F armature element 150. Progressing slightly in~lardly through passages 160 communicating slots 158 ~Jith central guide passage 156 the fuel is substantially straigten ancl smooth by the rel~aining length of the guide passage 155 the Reynold's number for the . flo~;J between the stem 146 and the actuator annulus 156 being calculated to 'be in the region oF 2900 Emerging from the mouth of the actuator 140~ the fluid -Flows between the stem 146 and the housin~ annulus 98 with a calculated Reynold's number of a stable laminar 1200 through the opening bet~;een the ball valve 148 and the housing annulus 98 where the Reynold's number jumps momentarily to approxima-tely 10 000. However with the :.
housing annulus 98 mergetl smoothly with the outer diameter oF the conical surFace 78 and with an actuatin~ stroke sufFicient to provide a 0.0~ to 0.15 mm clearance between the ball valve head 148 and the conical sur-Face 78 the flow therebetween drops to a low liminer Reynold's number oF 1900.
COMPARATIVE PERFORMANCE RESULTS
The superior performance oF the fuel inj~ction valve o~ the present . :~
invention may be better unders~ood as reference to Figures 6a 6b ancl 6c ~herein al'l the solid lines represent the reslllts obtained usiny an early developmental model oF the Fuel injection valve of the type shown in ~6 , Fi~ures 2-5 and wherein the dotted lines represent results obtained us;ny a conventional fuel injection valve of the ty~e shown ;n the Prior Art Figure. As sho~n in Figure 6a, the developmental fuel injection valve of the type disclosed herein provided noticeably better (lower) brake specific fuel consumption BSFC for all air fuel ratios up to 18.5:1 in the case of a 120 ft. lb. dynamometer load at 2,000 engine rpm or 19.5:1 in the case of a 70 ft. lb. load at 1600 rpm. As shown in Figure 6b, at an engine load of 70 ft. lb. at an speed of 1600 rpm the fuel injection valve of the present invention produces sli~h-tly lower carbon monoxide ; 10 (CO) emissions up to an air fuel ratio of 15:1, substantially lower hydro-carbon (HC) emissions out to an air ~uel ratio o-F 18:1 lower nitrogen oxide s ~rlOx) emission are generated above air fuel ratios of about 15~5 1a and the improvelnent becomes nlore pronounced and uniform at higher loads and - speeds where shown in Fi~ure 6c the fuel injection valve 10 of the present invention procluces uniFormly and substantiallY lower nitrogen oxide (NOx) emissions for all air fuel ratios, substantially lower hydro-carbon (HC) emissions, and slightly low carbon monoxide (CO) emissions.
RECAPITULATION
- As fully explained above, the fue1 injection valve 10 of the present invention is adapted to be sui~ably moun~ed on an internal combustion eng;ne 20 so as to be communicated with an intake passaye 18 thereof and comprises a tubular valve body 120 having a central s~epped bore 126 and 128 therethrough along a longitudinal valve body ax;s x-x. The valve body 120 comprises " annular hub means 124, C washer stop me~ns 108a and axially separated first and secondhold in means in the form of inwardly swageable lips 130 and 13~.
- The hub means 124 separate the stepped bore 126 and 128 into a coil and ~ inlet means cavity 129 and comprises the stop means pos-itionin~ surface 122 :,. .
.
and a first circumferential flux path surface 132 definin~ one side of a two sided radial air gap 1~3. The C washer stop means 108 ar~ positioned axially against the stop means positioning surface 122 of the h~lb means 124 and extend radially inwards therefrom so as to be abutable a~ainst radial surface 153 of ac-tuator shoulder element 152. The inlet connector means 190 are secured in the coil and inlet means cavity 129 by means of the in~lardly swageable lip 138 actin~ axially sn as to seat flan9e 192 against a seat 135 counterbored in the tubular body 120. The tubular inlet connec~
tor 190 comprises an outwardly extending flange portîon 192 intermediate an inlet tube portion 202 and an outlet tube portion 204. The inlet tube portion 202 is adapted to be connected as by fuel rail means 22 with a source of pressurized fuel and -together with the outlet tube portion 204 has a central fuel passage 194-212 therethrough along the valve body axis x-x.
. The outlet tube port;on 204 further comprises an annular terminating surFace 196 defining one side of a two sided axially air gap 168.
Fuel injection valve lO further comprises actuator housing means 90 secured in the actuator housing cavity formed by bore 126Of tubular valve body 120 and is held therein by the other of the valve body hold in means comprising inwardly s~ageable lip 130. The actuator housing means 90 has a central stepped-bore extending therethrough along the valve body ~.
axls x-x this stepped bore being separated by the valve seat and oriFice n-eans seat 96 into a fuel outlet bore portion 92 ancl an actuator bore portion 98. The fuel outlet bore portion 92 is terminated in fuei outlet . .
hold-in means in the form oF the inwardly swageable lip 94 and the actuator bore portion 98 has shoulder abutment means in the Form af lip 104 of counterbore 102 abuting against the valve body stop means in the form oF C washer 108. The valve seat and me-~eri~1g oriFice means 70 has an inlet side $0 and an outlet side 74 and comprises intermediate therebetween a centrally-located metering ori-Fice 76 the outlet end of which is con-~`
: tiyuous with an outlet surface 72 diverging towards the outlet sicle 74 and the inlet end of which is contiguous with two conticJuous inlet surfaces ~8 . and 86. Inlet surface 78 is conical and inlet surface 86 is partly spherical to define at their intersect;on the circular valve seat edge 88. Secured in the fuel outlet bore portion 92 against the outlet side 74 oF the valve seat and metering oriFice 70 are fuel outlet means in the form of the guide nozzle 50 and the thin fuel breakup disc 60. The fuel breakl~p disc - 60 colnprises a plurality of thin arcuate slots etched therethrough, each : slot havinJ a radial width of optimally not greater than 0.1 mm and an arcua~e length not less than twice this radial width. The number and lengths o-f tbe arcuate slots are selected to effect a total slot area whicll is at least 150~ of the area of the metering orifice 76.
The actuator means 140 comprises the armature means 1~4, and ball valve head 148, and the stem 146 and is loosely su~ported with a 0.007 to 0.035 ~m total clearance relative to the actuator bore portion 98 of actuator .. housing means 90 and are adapted to reciprocate axially therein along the valve body axis x-x between an open position and a closed position. The armature means 144 comprises a one piece guide element 15~, abutment element . :
. 152, and armature element 150. The abutment ele~ent lS2 is adapted to .; 20 abut a~ainst the valve body C washer stop means 108 to there establish the : open position of the armature. The armature element 150 comprises a second circumferential flux path surface 142 and a second transverse flux , .
path surface 164 cooperating with the first circum-ferentially flux surface 132 of hub 124 and the first transverse flux path sur~ace 196 of the outlet 25 tube portion 18~ to respectively define the otner sicles of the radial clir gap 1~3 and the axial air gap 168. The gu-ide element 154 of the armature ~eans 144 has an arcuate peripheral surface 166 loosely enga~ing .
the ac-tuator bore portion 98 so as to suFficiently center the actuator . nlealls to prevent the ~.lidth of the first and-second air gap 143 and 166 from ~: ~
.' ~ .
.
~ ~9~)04 bein~ less than first and second predeternlinecI air Japs. The guide element 154 and the armature element 150 of the armature means 144 also have a flo~l smoothing fue1 passage means 156~ 160, 158 and 162 therethrough .~ communicating with the central ;nlet passage 194 means 218 and 212 of the inle-t connector 190.
The valve head and stem means 1~8 and 146 have a free end terminated in the partly spherical valve head 148, a fixecl end terminated centrally in at bore 149 of armature element 150, and a stem length inter-mecliate this free end and fixed end telescoped by the portion 156 oF the central lq -Flow smoothing passage means. The stem 146 has a radial clearance in bore 156 as the partly spherical valve head 148 is guided by the partly spherical valve surface 186 to sea-t on the circular valve seat edge 88 and there establish the closed position oF the actuator means `140.
. Spring means in the form of the helical spring 214 are positioned between the fixed radial end 216 of the outlet tube portion 204 of the inlet connector 190 and the reciprocable terminating radial end 264 oF armature element 150 to normally biased the actuator mean$ 140 in a direction l~rom :~
the tubular inlet means 190 toward the valve seat and orifice means 70.
; Electromagnetic coi.l means 250 are positioned in the coil and , . .
inlet means cavity 129. Intermediate the valve body hub means 12~ and the inlet flange portion 192 and are operative when energized to establish . . a magneto motive force on the armature element i44 sufficient to overcome : the closing bias o-f spring 214 to move the actuator means 140 from its closecl position to its open position.
:~ .
,. , .
. . ,.
::`
.
~a~o~
CONCLUSION
Havin~ described several embodiments of the invention, it is understood that the specific terms and examples are employed herein ;n a descriptive sense only and not for the purpose of limitation. Other 5 embodiments of the invention, modiFication thereof, and alternat-ives thereto will be obvious to those skilled in the art and may be made with-out departing from my invention. I thereFore aim in the apended claims to cover the modifications and chan~es as I would in the true scope and spirit o~ my invention.
,. . :
.
.
. .
of the par-ticles. Moreover, circular holes o~ the requisi-te smallness are difficul-t -to fabricate repeatably even by etchiny. The analysis by Raylei~h in his "On the Capillary Pherlomena of Jets" (Proceedings of the Royal Society, XXIX pp 71-97, 1879, Rayleiyh, Scien-tifie Papers, Vol. 1, Dover Publications, 1964) is therefore also of interest to the present invention. There Rayleigh noted that non-circul.ar orifi.ces through thin plates produced flat broad thin liquid sheets of fluid. More recent analyses, such as by Keller and Koldner in the Journal of Applied Physics Vol.25 pp 918-21 (1954), show that thin sheets produce small droplets. However, it was not appreciated until recognized by the present .
invention that non-circular slots of the requisite small width could be etched more precisely than circular apertures with the result that the thin-plate-non-circular-slot thin-liquid-sheet small-droplet theory is not known to have heretofore been applied to ~uel injection valves. It is therefore desirable to improve fuel economy while at the same time reducing undesirable emissions by sb/
breaking up the metered fuel first into thin sheets and then into uniformly small fuel droplets. Conventional injection valves of the type noted above ~o l;ttle if anything to shape the envelope of the spray emitted from the annular orifice. This results in a wide angle spray that wets the sides of $ tne intake Passages so as to enter the combuskion chamber in an unevenly rich ; and lean distribution. The present invention recognizes that such wetting and uneven distribution ~ay be reduced by providing a spray-envelope~shaping nozzle as a part of the injector immediately downstream of the Fuel breakup disc.
The pressure drop across the fuel breakup means of a conventional fuel injection valve is another factor requiring very tight tolerancing of not only the metering or;fice but also the breakup apertures. Since the ; precision of the quantity of fuel injected on each injection pu1se is dependent on having a known flow rate while the inj~ection valve is op~n and since a known flow reqllires having a known pressure clrop across a known flow area, the area of any part of the flow path across which there is any si~nifican-t pressure drop must be known and therefore closely controlled.
The present invention therefore further recognizes that the size tolerances on the fuel breakup means could be relaxed by ef~ectins the breakllp function by a structure substantially separate From that effectin9 the metering Function ancl by then desiynin9 the Fuel breakup means so as to have a minimuln pressure drop thereacross. In otherworcls, the present invention recoynizes the desirability of providing fuel breakup nleans havin~ a sufFicient flo~l area and minimal axial thickness so as to not generate any pressure drop signifi-cant to Fu l flow accuracy. In this way the ^tolerances on the non~circularbreakup apertures could be determined, nok so as to effect a requisite pressure drop by means of a precisely known flow area therethrollgh, but rather to effect the renuisite drop size, the tolerances on the breakup apertures ~LC~ 3 4 being looser than those on a metering orifice. Moreover, the tolerances on the breakup apertures could then be held by the low co$t etching throu~h thin plates.
Convent;onal fuel injection valves introduce an undes;rable, and often vehicle disabling, "hot start" problem upon restarting or attempting to restart an overly hot engine before it has had sufficient time to cool do~,~n. More specifically, during the comparatively short time bet~een shutting down an engine in an overly hot environment and attempting to res-tart the engine, all the components under the hood exp~rience a ".hot soak" as the overly hot enyine conducts, convects, and radiates heat to the auxiliary componen~s. In the case of the ~uel injection valves, the temperatures thereof are so elevated compared to the temperatures associated with normal operation that the fuel is substantially vaporized before reaching the valving and metering elements. To the extent that the ., fuel is vapori~ed prior to bein9 metered, less liquid fuel is expelled : . .
from the injector during a given injection interval than is expelle~ under .nor~al operating conditions when the fuel is substantially .1iquid. Con-sequently~ to the.extent that more vaporized than liquid Fuel is injected into the inlet passa~es of the engine, a substantially leaner than desired 2q mixture is injected. Such leaner mixture is often insuFFicient to permitprnper i~nition, preventin9 i~lnition under the wor.~t cases and other~lise ef~ectin~ s~umbling to rough ignition under less severe cases as the mixtures richen up to the desired air-fuel ratio. The duration oF such undesirable lean mixture perForn1ance varies primarily with the difference between the hot soak and normal operat.-ing temperatu.re and the rate at which the hot soak thermal energy is removed From the injector.
~6--.
o~
To avoid such "hot restart" Droblems, it is desirable to reduce the problem-causin~ conduction, convection, and radiat;on o-f heat from the engine to the injectors and then to eliminate whatever hot soak energy is transfèred thereto as fast as possible upon hot restarting. More speciFi-cally, it is desirable to minimize the initial conduction oF hot soak energyto the injectors by minimizing the surface contact area between the engine and the injectors and by minimizill~ convection and radiation by increasing the air space between the exterior of the enyine and the exterior oF the in~ector. Furthermore, to reduce the time required to remove whatever heat has been transfered to the injectors, it is desirable to reduce the cross- .
sectional area oF the injectors so as to increase the air space between the engine and injector, to reduce the storect hot soak ener9y that must subse~
quently be removed, and to other~lise maximize the rate that heat is trans-ferred from the body oF the injectors.
In solving this problem, the present inventinn recognizes that smoothly-flowiny normally-cooler fuel has a higher coefficient of heat transfer than turbu.lently flowing fuel and, not beincJ turbulent, can be metered more precisely. In this re~ard, the present invention recogni~es that it is desirable to incluce a substantially smooth flo~Y and to clo so by a substantially straight and llnimpeded central fl~el Plow innlecliatel;y upstream of the valve and orifice rather than the prior art sicle-ported and peripherally-chanelled fuel flow of the types producecl by tlle valves disclosed in the above mentioned patents.
A further primary function effected by a fuel injection valve is to repeatably and rapidly actuate the valve by the electromagnetic inter-action between the flux produced by a fixed coil acting on a moYable pl~lncgeror armature connected to the valve head. Conventionally, the actuator is electromagnetically opened to a position determined by the abutlllent of a shoulder protruding From the actuator,against suitable abutlnent on the valve body such abutment norn1ally being in the form oF a "C" ~Yasher. Upon ::de-energizat;on of the coil the actuator is sprin~ closed to a closed posi-tion determined by seating oF the valve head on the valve ~eat. To effect as rapid a response as possible with the establishment oF a threshold l~vel oF magnetomotive force by the coil, the actuator is made as light as possible and the magnetic lock up between the fixed and mavable elements is prevented by ma;nta;ning min-mum ma~netic air gaps for the magnetic flux. ~n addition to permitting a fa$ter opening response, a light actuator permits the use of a ~leaker closing spring to effect softer closing and thereby a1so reducing the pounding wear bet~Yeen the valve head and valve seat.
The outer surFace of a conventional actuator and the matin~ inner surface of a conventional actuator housing are therefore heat treated and closely toleranced as ~o diameter and squareness so as to pro~Jide a durable slidin9 metal-to-metal contact, Such close tolerancin~ is required: 1) to enable the actuator to precisely pilot and center the valve head on the valve seat;
23 to precisely pilot and center the.pintle needle in the metering orifice~
and 3) to maintain the minjmum magnetic air ~aps axially between the r~ar encl oF the armature and the Front of the Fuel inlet tube and also radially between the outqr diameter of the armatllre ancl the inner diameter oF the matin9 valve bocly. It is clesira~le to avoicl heat treatnlent and relax ~h~se tolerances especial'!y s1nce they must othenYise be ma;ntained on substant;ally blind and very small actuator housing bores.
The present invention reco~nizes that an actuator which is tubular in form enhances such lightness in adclition to also inducing a smoothing better-coolijn~-and-meterin~ eFFect on the central flow therethrough. Moreover, ~06~09~
' .
, the present invention further reco~nizes that, rather than providing a sliding metal-to-metal contact between the actuator and its housing, it is more desirable to do the opposite by providiny an ample positive clearance therebetween to allow the resulting surrounding pressurized fluid fuel to su-fficiently center the actua-tor to effect the necessary sea-ting and to - maintain the minimum air gaps. Also, lower actuation energy is requiredwhen the actuator slides on a fluid rather than me-tal surface, also per mitting a weaker closing spring resulting in lower closing impact and longer actuator life. The present invention further recognizes that a pos itive clearance between the actuator and its housing aiso enables the actuator to provide some of the flexing action otherwise required oP the stem ~o properly seat the stem-mounted ball valve head on the valve seat.
More specifically, the length of the actuator telescoping the stern and free to move in the positive clearance acts as extension oF the stem and thereby r~duces the life limitln~ flex stresses that would otherwise be imposed thereon.
A further cost imposing feature of conventional fuel injec-tion valves heretoFore used with commercial passen~er vehicle fue1 injection systems is that the electromagnetically responsive armature is mo~lnted on a non-magnetic actuator. Not only is the non ma~netic Inaterial more costly perpouncl by half again as much as the md9netic material, bilt the s~para~e armature and actuator parts require close tolerance machining oF the requisite mating concentric bores in the armature and receiving surfaces on the actuator followed by the close tolerance axial positionin~ of the armature on the actuator. The rnain reason requiring such separate materials apparently was the previous belief that, unless the actuator was oF non-magnetic material, tne motion limiting stop shoulder thereoF would efFect a magnetic lock-up with the magnetic return path of the valve body and would there~y unacceptably slow the opening and clos;n9 t;mes of the injector.
_9 The present invention recognizes that any ma~netic lock-up bet~leen the actuator shoulder and valve body is second order compa~ed to that possible between cylinclrical outer surface of the armature and valve body because the latter prov;des not only the shorter flux return path inherently efFected by magnetic flux but also provides more matin~ gap sur-face. The present further recognizes that, rather than suffering the cost and other penalties of provicling an armature and actuator of difFerent materials, it is fea$ible and more clesirable to do the opposite by making not just the armature and actuator but also the actuator housing out of the same material.
By doing so avoids the differential thermal expansion rates hereto-Fore resultin~ from different coefficients o~ expansion. Also avoitled is the growth of crystals in the gaps normally resulting from the galvanic corrosion reaction conventianally occuring between the dissimilar materials of the actua-tor and its housing, such similar material thereby further reduc;ng the friction therebetween while increasing valve life by avoiding catas trophic galvanic-growth-induced sei~ure of the actuator to its housing.
Yet another problem heretofore experienced with electromacgneti-cally actuated fuel injection valves is that the welded connections between the end oF coil wire and the output te ~I;nal of the injector oFten break when th~ output terminals are wig~led on the assembly, connector molclin~
testin~, shipping, or sub~sequent encJine mountirl9 ancl connection oP the injector. Conventional fuel in~ection valves oF the type noted above attempt to avoid these problems by the use of L-shaped terminals that enter the in-jector axially ancl then, make an "L" turn in opposing circumPerential direc-~5 tions so that the inside of coil bobbin and/or inlet connector flange prevents the terrninals from being rnoved axially. Such terminals of course are not stampecl out Prom lo~er cost straight r;bbon stock of term;nal wi~th. It f is -therefore desirable to provicle a straight narrow terminal that can be securely anchored within the bobbin.
., . I .
.
It is -therefore a primary object to provlde a new and useful fuel injection valve havin~ a cost substantially less than that of conventional fuel injection valves mass produced vehicle fuel injection systems.
It is a further object of the present invention to provide a fuel injection valve comprisiny a coil bobbin and terminals for electrical connection with the ends of the coil wherein the coil bobbin comprises an axially extending terminal-insulating-post having a dimple locking wall at one end of a welding aperture over a terminal slot and the terminal comprises a thin axially extending section having a dimple across sub-stantially the entire width thereof, the dimple being retained by the dimple locking wall.
1'he present invention resides in a fuel inlet assembly for a fuel injection valve having a fuel inlet connector comprising an inlet tube portion se~arated from an outlet tube portion by a radially extending flange portion, the flange portion having at least one terminal insulating post aperture therethrou~h between first and second flange sides. There is provided a coil and terminal assembly including a coil bobbin and a thin terminal. The coil bobhin has :Eirst and second radially extending flanges separated by an axially extendincJ
~-entral portion positioned on the outlet tube portion, one of the bobbin Elanges including a terminal insulating post extending axially therefrom throuyh the aper-ture.
The terminal insulating post has Eirst and second ends separated by a thin slot extending the axial length of the post, the first end terminating at the one bobbin flange and the second end terminating outboard the . .
. - 11 -~ sb/
~69(~
second inle-t conncctor flange side, the terminal post further including an oblong opening having a floor deEined by the thin slot and a dimple :locking wall extending radially outwards intermediate the first and second ;~
terminal post ends. The thin terminal has a narrow length portion received in the thin slot, the n~rrow leng-th portion having a di.mple across substan-tially the entire width thereo:E, the dimple beiny engaged by the dimple lockiny wall to restrain the thin -terminal from axial movement in the thin slot.
FIGURES
FIGURr~ 1 is an end vi.ew of a preferred embodiment of a fuel injection valve constructed in accordance with the present invention:
FIGURE 2 is a view of the fuel i.njection valve of Fiyure 1 taken along partially rotated view 2-2 thereof;
; FIGUP~E 3 is a view of the fuel :i.njector valve o:E Fiyure 2 taken alony view 3-3 thereof showing a fuel ~ breakup disc etch~d with thi.n-slot apertures therethrough .~ 20 in accordance wi-th a preferred configuration of the present invention;
FIGUR~ 3a, which appears on the same sheet as E'iyure 5, .is a plan view of an alternat.ive configuratlo of slots etched throuyh a thin breakup clisc;
FIGUR~' ~ is an en:Laryed and exaygerated view oE
the valve seat and o.rifice portion of the fuel injection valve of Figure l;
F:CGURF 5 is a plan view of a fuel injection valve of ~igure 2 taken aloncJ view 5-5 thereof so as to show :. 3~ the combination of an elec-trical terminal with an insulator post;
FIGURE 6a, 6b and 6c shows and compares the bra~e specific fuel consumptio~ (BSFC) and emission results a-t .
~ .2 -; sb/`
.. . . .. .. . . .
- ~69~
di~Eeren-t enc~ine loads and speeds for different air fuel ratios of the fuel injection valve of -the present invention (solid lines) and of -the prior ar-t (dashed lines), Fig~lre 6c appeaxs on the same she~t as Figure 5;
FIGURE 7 .is a sectional view of a conventional fuel injec-tion valve.
. With reference now to the conventional fuel injec-tion valve shown in Ficture 7, there is shown a pintle-type fuel injec-tion valve comprising a valve body A and a valve needle B that has its tip -forced tightly against a valve seat C in the valve body by a compression coil spring D, thereby tiyhtly closing the valve opening E. The needle valve B is provided wi.th an armature F of material which conduc-ts the magnetic flux generated by a mayne-tic coil G. The delivery o:E
exciti.ng current from a suitab:Le source to the magnetic coil will. cause the armature ~' to move in an axially direction (towards the riyht in Figure 7) until a projection Il on -the valve needl.e B abuts against ~ 20 a stop ~ in the valve body~ The valve needle ~ is centered '~ wi-thin a hore K of valve body A by a cylindrical first land L spaced axial.l.y ups-tream on valve needle B Erom plurali-ty of axially extendinct lands M pxojec-tincJ
xad:ially outwards from the valve needle B and provicliny corresponding plurality of axial:ly extending peripherical passages therebetween. When -the valve C is opened, fuel under sui.-table pressure is communicatecl by a suitable condu.i.-t N to a fuel i.nlet end P of the injector and flows centrally therethrough and throuyh a tubular core element ; 30 Q to the -tubular rear end of valve needle B. The cen-tral bore R of valve needle B extends axially inwards from the core end of -the valve needle B -to a point intermediate ' .
~-.;;.~, - 13 -sb/~
~` ~069~0~
lands I, and M and there passes r~dially outwards through a pair of suitable radial apertures S. The flow of fuel proceeds ~xially therefrom abou-t valve need].e B past land M and valve seat C exiting in the annu].us defined between valve opening E and needle T, the dimensions o~ the annulus between the needle T and opening E determining the size, distribution, and cone angle of the droplets comprising the fuel spray.
DETAILED DESCRIPTION OF INVENTION
` 10 Turning now to Figures 1 and 2, there is shown a fuel injection valve 10 adapted to be positioned by a resilient rubber grommet 12 and a gas back-flow shield cap 14 in a counterbore 16 suitably provided in an intake ~ passage 18 continuously or intermittently communicated with one or more combust:ion chambers (not shown) o:E an internal combustion engine 20. Fuel injection valve 10 is further adapted to be communicated with, and biased towards counterbore 16 by a fuel conduit means 22 such -:
as of the type disclosed in tlle commonly-assigned United States patent to Wertheimer et al 3,776,209, entitled "Fuel Injector ~anifold and Mounting Arrangement", issued December 4, 1973. At its injector end conduit means 22 . comprises a circular groove or counterbore 2~ ~or receiving an elasti~ ~nd deformable circ~llar seal 26. At its pump end, conduit means 22 is communicated with suitable ~uel pump means 28 adapted when energized to pump ~uel 30 at a suitable p.redetermined pressure such as 39 psig from a conventional fuel tank 32 via a suitable fuel line 3~.
Fuel injection valve 10 is fur-ther adapted to be electrically communicat~d by means of conduc-tors 36 and 37 and an electrical connector (now shown) with an electronic computing unit (ECU 38) comprising circuits ~ ' . .
sb/`~
: : .
' 3L069~04 o~ the type disclose~ in commonly-assigned United Sta-tes patents to Reddy 3,734,068, entitled "Fuel Injec-tion Control System," issued May 22, 1973, 3,725,67~ to Reddy, issued ~pril 3, 1973, 3,919,9~1 issued November 18, 1975.
Electronic computing unit 38 is suitably coupled electri- ~' cally and mechanically with engine 20 to receive information ; therefrom in the form of engine speed (RPM) signals 40, ~ temperature signals 42, and manifold air pressure signals : 44.
Starting at its outlet or left end as viewed with respect to Figure 2 and working clockwise towards its inlet or right end, fuel injection valve 10 comprises conical spray forming means in the form of an outlet nozzle 50, uniform fuel breakup means in the form of a thin break-up disc 60, metering means and valve seat means i.n the form of a valve seat and orifice means 70, a tubular actuator housing means 90, tubular valve body means 120, actuator means 1~0, a molded electrical connector plug assembly ; 170, and inlet connector means 190, and inlet filter means220, and a bobbin and terminal assembly means 2~0.
Nozzle 50 Nozzle 50 comprises a conical surface 52 there-through diverginy Erom an a~ial inlet end radial surface 5 to an outlet end radial surface 56, and 18 conical angle of conical surface 52 being selected to tailor the spray envelop of the fuel droplets ejected by injector 10 to be compatible with a particular configuration of inlet passage 18 and/or the combustion chamber intake valves ~not shown) of internal combustion engine 20. The circular pheriphery of noz~le 50 is positioned cen-trally in an outlet bore 92 of valve body 90 and comprises intermediate inlet end surface 54 and outlet end surface 56 suitable hold-in means in the form of a circular external shoulder 58 ~ 15 -sb/~
.
~L0~9~
.
for cooperating ~lith suitable valve bo~ly hold-in means in the forrn oF a raclially inwardly swayeable lip 94 to èFfectively secure no~zle 50,spray disc 60, and valve seat and oriFice 70 within housing outlet bore 92 a~ainst radial seat 96 counterbored at the inboard end thereof.
Fuel Breakup Disc 60 As rnay be better understood in conjunction with Figure 3, fuel b,eakup disc 60 comprises a thin (0.05 mm) sheet having chemically etched tilerethrough Four-slot groups 61a-d, 62a-d, 63a-d, 64a-d, 65a-d~ and 66 a-d grollped by sectors and positioned radially outboard o-f a seventh equi-angularly-spaced three-slot group 67a, 67b, and 67c. One arcuate . end of each slot in groups 61-66 commences at an arcuate position rotated 5 clockwise when viewed with respect to Fi~ure 3 From the starting arcuate encl of the next radially inboard slot of the same group, and the other end of each slot in a group 61 to 66 terminates to include 6 more than the -15 nex-t radially inboard slot o-f the saml group. In this m~nner, the arcuately ,. shortest slot in group 61-66 is 30 and the longest, being the fourth slot and thereFore having ~4 greater de~rees of inclusion, is 48. Each of the three slots 67a-c include an angle of 60.
Each slot has a typical width oP 0.05-0.07 mm ancl has an illner raclius spaced from the inner rarlius of the next ad~iacent radially outboarcl slot of 0.1~3 to 0.25 mnl. Th~ 0.20-0.25 n~n radial spacing between the outer radial edge of one slot and the inner radial edge of the next rad;al outboard slot is selected to prevent congealing of shee~s of fuel developed byacljacenl: slots and a1so to permit efficient chemical etching thereof. The o.n5-0.07 mm radial slot thickness has been founcl to permit the breakup of fuel into uniformly smal l droplets oF less than 100 rnicrons in diameter ith a standard deviation of less than 100 microns and may be satisfactorily ~leveloped with conventional etching or possibly stamping processes.
'' . .
- 1 6 - ~
', 1.
.
~06~00~
The total number of slots, here 27, their radial ~/idths, and their arcuate len~ths are selected so that, for the 0.05 nlm typical thickness oF
the disc 60, and a typical fuel pressure of 39 psig, the total flow area through the slots is more than 150% of the flow area of orifice 76 valve seat and orifice means 70. With such dimensions and fuel pressure, substan-- tially the entire 39 psig is dropped across the metering orifice 76 so that the flow area of the metering orifice determines the magnitude of the Flow rate.
As sho~n in expanded detail in Fi9ure 4, to provide a suitable clamping surface between nozzle surface 54 and a radial surface 7~ at the outlet end of valve seat and metering orifice 70, fuel breakup disc 60 comprises an uninterrupted radial surFace 68 radially outboard oF the outer most arcuate slots 61a, 62a, 63a, 64a, 65a, and 66a. Moreover, so that unimpeded spray may be developed throu~h these outer slots, the inner dia~
meter oF the uninterrupted surface 68 is somewhat less than the inner dia-meter of either divergent nozzle inlet surFace 52 at its inlet side 54 or ; the outlet diameter of the divergent conical outlet surface 72 o-f valve seat and orifice 70.
While shown as a structure separate from that of actuator housing 90, nozzle 50 and valve seat and orifice 70 could both be macle as a part ; tllereof, A suitable disc receivin9 groove could then be un~l~r~llt radially between nozzle 50 and v~lve seat and oriFice 70 to allow thin fuel breakup disc 60 to be snapped into the undercut groove by suitably spring shapin~
the disc into a conical bevel form while pressing it uniFormly and evenly into nozzle 50 from its outlet end 56.
While a presently preferred embodinlent of the configuration of fue1 breakup disc 60 is shown in Figl~re 3, an alternate -Forrn thereof is shownin Fi~ure 3a wherein the arcuate lengths of the various radially adjo;ning arcuate slots are the satne as ttle arcuate lengths clescribed for slots of ~(~69~
.
sirnilar raciius with respect to and shown in Figure 3 the only signi~icant difference being that the slots are all equi-anyularly spaced ~ith respect : to other slots of the same racl;us rather than bein~ grouped by sector.
Valve Seat and Orifice 70 As may be better unders~ood in conjunction with the expanded view thereof oF Figure 4 valve seat and orifice 70 is annular about valve axis x-x and comprises a smoothly-finished substantially-centrally-located .
circular orifice 76 hav;n~ a 0.25 to 0.41 ~m axial-length less than its 0.4 mm up to 1.6 mm radial diameter. Orifice 76 communicates a divergent generally conical outlet surface 72 with a convergent 9enerally conical .
90 inlet surface 78 terminating at its outer diameter in an annular radial seatin9 surFace 80 the outer diameter of conicai surface 7~ being substantially the same as or mer~ing smoothly with an actuator housin~
~; ~ annulus bore 98 in actuator housin9 90. Intermediate its inlet and outlet seating surfaces 80 and 74 r~spectively valve seat and orifice 70 comprises a pheripheral cylindrical groove $2 containing an O ring ~4 suitably com-pressed aga;nst outlet bore 92 of actuator housin~ 90 to provide a seal thereat. Intermediate inlet seating surface ~0 and metering oriFice 76 the generally conical convergin~ inlets surFace 78 co~prises a sc.~mi-? spherical ball valve seat ~6 terminating at its outer cord ~7 in a finish~d circular seating edge 88 loosely conccntric with mPtering orifice 76.
Metering orifice 76 is fabricated by First drillin~ or other~ise roughly forming an initially-ùndersized aperture through valve seat and orifice 70 :.
and then forcing or "ballizing " a Finished precision bail of final orifice 25 diameter therethrough from the inlet side to the outlet sicle. Thereaftersemi-spherical ball valve seat 86 and circular valve seat eclge $8 are formed in a one step prncess of forcing o~ "coinin~" a Finishecl precision ball 89 of a diameter slightly greater than a ball valve 14~ of actuator 140 into the then unheat-~reated conical surface 7$. ThereaFter~ valve sea-t arld orifice 70is mechanically .deburred and pacivated anci heat treated. ~ .
, 1~ .
~0690ia 4 ':
Valve seat and oriFice 70 is suitably sized as to metering : diameters inlet surfaces and outlet surFaces etc. for each different engine application and can be made either as a separate element as shown . or as an integral part of actuator housing 90 thereby in one step saving at least the cost of an 0 ring 84 in addition to machining such surfaces as the outer diameter 91 of the valve seat and orifice 70 as well as groove 82 therein and inlet seating edge 80 thereof as well as outlet bore 92 ~nd counterbore seat 96 of actuator housing 90.
Actuator Housin~cJ gO
10 ... As has already been described with respect to outlet nozzle 50 .l and valve seat ancl oriFice 70 actuator housing.90 is generally tubular in form about valve axis x-x comprising an outlet bore 92 defining an outlet cavity 93 separated by a counterbored seat 96 From an actuator bore 98 defining an actuator cavity 127 and terminated at its axially-outboard - 15. outlet end by nozzle hold in means in the ~orm o-F radially inl~ardly s~ageable . lip 94. At its axially-opposite outboard inlet end actllltor housing 90 conlprises an axially extencling lip 100 cleFinecl by a collnterbored cavity 102; and tetmin~ted in a raclial abllting surFace ln~. Upon assembly ~Yith valve body 120~ radial abuting surFace 104 engages a first radial surFace 106 . 20 of a C washer 108 so as to secllrely posit.ion the other axial side 11~
ther~oF ~gainst an annular seat 122 counterbored into an annular hub 12~.
~ ~lub 12~ is located intermediate and actuator annulus or bore 126 bored into .. one end of the valve body 120 to thereby de-Fine an ac-tu~tor cavity 127 and inlet and coil asselnbly bore 12~ bored in-to ~he other encl ~lereof to thereby ; 25 define a coil and inlet assembly cavity 129.
, ~
~L()6~C~C74 Intermediate its radially swageable lip 9~ and axial lip 100, the periphery of actuator housing 90 comprises a shield cap peripheral surface 112 and a larger d;ameter valve body peripheral surface 114 .-separated by an undercut groove 116 and radial shoulder 117. Shield cap surface 112 is selected to provide a snug -Fit with the internal cylindrical surface 15 of shield cap 1~, and valve body peripheral surface 114 i5 selected to provide a snug fit with actuator housing bore 126 of valve body 120. Radial shoulder 117 comprises hold-in means cooperatin~ with mating hold-in means in the form of a radially inwardly swageable lip 130 of valve body 120 to urge actuator housing 90 and C washer 108 against counter-bored seat 122.
Suitable seal means in the form of an O rin~ 118 is captured in an O ring groove 119 on the periphery oF actuator housing 90 and suitably .~ . seals periphery 11~ thereof against actuator housing bnre 126 of valve body .
120.
; ~ VALVE BODY 120 As has already been described with respect to the actuator housing 90, valve body 120 is tubular about valve axis x-x and compresses there-through an actuator housing bore 126 separated by an annular hub 12~ From a .. . .
coil and inlet bore 128. The outboard outlet elld of actuator housing bore 126 is terminated by lip 130 that is radially swacleable inward~y to e~gage raclial shoulder 117 of annular lmdercut gronve 116 of actuator housing 90.
Annular hub 124 comprises an axially extending cylindrical surface 132 that together with an axially extending cylintlrical surface 1~2 of actuator 1~0 2S defines a predetermined m;nimum axial gaP 1~3 o~ about 0.23 to ~.38 mm.
At its inlet end, valve body inlet bore 128 compr;ses a counterbore 13~ --- 20 -- ~
69~
axially intcrmediate an annular raiclal seat 136 and a terminating radially in~ardly s~ageable lip 138. Ilhen swaged inwardly lip 13g that holds a flan~e 192 of inlet connector 190 against counterbDrecl seat 136 to position flange 192 both radially and axially with respect to valve body 120.
Actuator 140 comprises a one piece tubular armature 144 a flexible stem 146 and a ball valve 148 all located either about or along valve axis x-x. The tubular armature 144 in turn cornprises an armature element 150 separated from a guide element 154 by a radially outwardly extending shoulder element 152. A free end 147 of thin flexible stem 1~6 is ~elded to ball valve 148 ~\ fixed end of the stem 146 is centrally positioned in a small hore 149 through the rear quarter of armature element 150 and is suitably affixed ax1ally outboarcl thereof such as by brazin~
wel(ling or staking. Telescoping a substantial length of stem 1~6 is a celltral passage 156 opening at its outlet end into actuator bore 9~ towards ball valve 148 ancl terminating at its inboard end at bore 149. The internal diameter of central passage 156 is substantially greater than the ex-ternal diameter o~ flexible stem 146 so as ~o provide a free flowincJ 1.60 to 1.79 mm total clearance therebetween in which stem 146 may flex freely about its end fixed in bore 1~9 as ball valve head 148 seats in its slightly oversizecl ball valve seat 86 in comirlcJ to a closed position at circular ~dge 88 thereoP~Along the periphery 142 of armature element 150 are a pair of d-iametrically opposed slots 158 cut radially ~80 apart from the rear of armature elelnent 150 to a cliameter slightly less than tha~ the internal diameter of central passacJe 156 so as to provicle a firs~ free flowing 0.49 x 10.16 rnm passage 160 between central passage 156 and each axially extending peripheral slot 1~8 and a second free flowing 0.49 x 2.47 mm passage 162 through the ra(lial-exterlding end surface 164 o~ armature element 150.
.'' , '' . .
~Lof ;~90~4 ';.
Arnlature element passa~es 160 and 162 thereby freely con~unicate central passage 156 of actuator 140 with a central outlet bore 194 of inlet connec-tor 190 so as to provide an ample passa~e for fluid flow therebetween.
The periphery of armature tJuide element 154 comprises a cylindrical surface 166 of external diameter selected with respect to the internal . diameter of actuator bore 98 of actuator housing to ef-Fect a loose fit of about O.Q07 to 0.035 mm total positive clearance therebetween. The 8.1 mm ~IxiallY
-~ lerlgth of guide periphery 166 is selected to be sli~htly greater than twice the 4 mm diameter thereo-F. This positive clearance/loose fit ~etween the external periphery 166 of t~uide element 154 and the internal bore 98 of actuator housing 90 allows pressurized fuel to be forced between and thereby roucJhly center actuator 140 in both actuator housing bore 98 valve botly bore 132 so that with the actuator 140 ;n its open position defined whcn . raclial surface 153 of shoulder element 152 abuts radial surFace 106 of washer 108 the radial air gap 143 between the armature periphery 142 and hub axial surFace 132 is not less than about 0.22 mm and the axially air gap 168 bet~Jeen arrnature end surface 164 and a radial end surFace 196 oF
inlet connector 190 is not less than 0.06 mm.
MOLUED P~UG 170 Molded plug 170 comprises a rectanglllarly-shapecl connector recepticle portion 172 protrudintJ Prom an annular hllb portioll 174 ~t an an~le of about 60 with respect to the longitudinal actuation axis x-x oF
fuel injector 1~. Hu~ portion 174 ~rotrudes axiall.y fronl ~ Flange port-~on 176 encompassin~l and sealintJ the valve boflv lip 138 as l~ell as inlet connector ~ldnge 192 antl terminal insulator posts 2~2 and 244 oF coil arl(l bobbin assenbly 240. Hub portion 174 and flan~e ~portion 17~ are canivated axially in tgroove 198 of inlet connector 190 bet~Jeen a side 286 of inlet connector flange 192 and a shoulder 205 intermediate groove 198 and a shoulder 206.
Annular hub 174 comprises a pair oF oppositely clisposecl s~ake holes 17~ and . . .
9~4 ... .
1~0 extending radially therethrough to allow the ;nsertion o-F a stak;ng tool for the purpose of de~orming an annular sroove portlon 1~8 o-F inlet connec-tor 190 so as to position a sprin9 acljusting tube 200 in b~re 194 therenf.
Electrical recepticle portion 172 is terminated a~ its ou~.board end by a rectangular peripheral lip 182 t)ounding a rectangular tapered cavity 184 having a pair of inwardly tapered sides l~a and 186b clefining the long sides of the rectangular cavity 184 and telescopins so as to centrally position therebetween a pair oF electrical terminals 2~6 and 2~ protruding through hub portion 174 from terminal insulator posts 2~2 and 244 respectively.
Beveled downward into cavity 184 along a portion o-F tapered side 186b thereof is a inwardly-sloping down surface 187 having a ~air of remale semi-cylindri-cal key grooves ?88a and 188b formed therein. The long rectangular sides 186a and 186b and the short rectangular sides 189a and 189b of cavity 184 are tapered inwardly to provide a wedgin9 action against an electrical ; 15 connector (not shown~ when inserted -therein.
Inlet Connec-tor 190 Inlet connector 190 cotnpri$es a radial flange portion 192 inter-mediate an inlet tube portion 202 and an outlet tube portion 20~. FJan~e surface 286 comprises radially extending knurled identations 193 at the radiallyoutboard edges thereoF to lock flanye 176 of molcled plug 170 and also lip 13~ of valve body 120 against relative circumFerential motion about valve body axis x-x. The periphery of inlet tube portion 202 comprises the de-formable circular yroove 198 intermediate flange portion 192 and a circular raised shoulder 206. At its inlet end, inlet tube 202 comprises a recessed surface 208 terminated in a radially outward extending shoulder 210 for seatin~ 0 ring 26. Passing c~ntrally through inlet connector is a stepped-bore comprising an inlet bore 212 and the smaller outlet bore 194. Inlet bore ; 212 extends into inlet tube portion 202 a length sufficient to anl~ly enclose inlet filter assembly 220, and outlet bore 19~ passes throush the ren1ainder - 23 - ~ :
:, :
o~
oF inlet tube 202 as well as throu~h flange 192 and o~ltlet tube portion 204.
Outlet tube portion 202 terminates in the annular radial surface 196 wh;ch Forms one side of the axial air ~ap 16~ the other side oF which is formed by ter~inating radial end surface 164 of armature ele!nent 150.
Suitably positioned within outlet bore 19~ are the spring posit-- ioning tube 200 anci a helical sprin9 214. The outer cylindrical periphery of spring positionin~ tube 200 is knurled or othenYise suitably deformed so as to suitably lock against outlet bore 194 when annular srQove 198 is deformed . inwarcily by staking upon assembly throu~h molded plug apertures 178 and/or . 10 180. When stakecl, the axial position oF t~bular spring positioning tube : 200 within outlet bore lg4 is selected so that "~ith one end oF helical spring ; 214 positioned against an annular radial terminating shoulder 216 and the . . other end positioned against the radial end surFace 164 of actuator element j; 150, spring 214 imparts to actuator 140 the proper bias to efFect the . 15 desired opening and closing dynamics characteristics thereof. Moreover, to more carefully tailor the maynetic circuit provided by coil and bobbin assembly : 240 when energized, a pair oF thin slots 218a and 218b (not shown) are cut 180 apart on the periphery 219 at the outlet end of outlet tube portion 204, the axial slots 218 also further enhancing smooth flow oP Fuel into passacJes ZQ 158 of armature element 150 ~lhile also reducin~ the edd~ currents produced in inlet connector 190.
'. Inlet Filter Assembly 220 . .; .
.;j As described above with reFerence to the inlet connector 90, ~ . .
. inlet Filter assembly 220 is con~ained within inlet bore 212 oF inleL
connector 190. The inlet Filter assembly 220 forms a flat-end-shaped axially-'`'t extendin~ pocket formed by a pair oF screens 222 and 224 of about.325 mesh.
The screens 222 and 22~ are joinecl by suitably inte~rally molding their ~eri-phery into a common frame havin~ a pair of webs ~27 connecting a flat end 226 ~ith an annular collar 22~ formin~ an inlet opening at the mouth of inlet j~
~.... 30 connector 190. Annlllar collar 22~ is molded over the per.iphery of screens .~,. . .
,~- 222 and 22~ and is pressed fitted into inlet bore 212.
':
' ~ ' . .
;9~
The above described fuel injection valve is also disclosed and is claimed in above-identified parent application Serial number 273,500.
Bobbin and Coil ~ssembly 240 Bobbin and coil assembly 240 comprises a coil 250 of about 306 turns of magnetic wire wound on a spool like bobbin 252, coil 250 comprising a beginning inner end 254 and a terminating outer end 256 seen better in Figure 5. Spool 252 comprises an armature end radially extendiny flange portions 258 and a flange and radially extending flange portion 260, flange portion 258 and 260 being integral with but separated axially by a central axial portion 262 positioned along valve axis x-x within valve body cavity 129. The axially outboard sides of flanges 258 and 260 comprise respective annular lips 264 and 266 protruding axially therefrom. Lip 264 comprises - an external shoulder 268 cooperating with flange 258 to urge an 0 ring 270 outwardly against valve body bore 128, and lip 266 comprises an internal shoulder 272 cooperating with flange portion 260 to urge an 0 ring 274 of the same diameter as 0 ring 118 inwardly against periphery 219 of outlet tube portion 204.
At its axially outboard end annular lip 266 terminates in an annular radial surface 278 seated against a coil and spool side 280 of connector flange 192, and a small sector of flange 260 and lip 266 thereof compris~s the terminal insulating post 242 and 244 as also seen more clearly with respect to Figure 5. Terminal insulating posts 242 and 244 project axially through a pair of circular apertures 282 and 284 (not shown) provided through connector flange 192 and respectively receive terminals 246 and 248 inserted from the inlet connector side 286 .
sb/ ~ - 25 -6900~
of connector flange 192. ~he leng-th o:E each of the terminals 246 and 24~ comprises a narrow leng-th portion 288 separated by a neck 290 from a comparatively wicler length portion 292, narrow portion 288 having an upwardly protruding conical dimple 294 formed su.bstantially thereacross. Each of the terminals insulating post sb/
~9~4 comprises an arcuately narro~.l slot 296 passin9 axially therethrough and of a radial thic~ness substantially the same as the radial thickness of the narro~.~ portions 288 of terminals 242 and 244. Each of the terminal insu-lating post 242 and 244 comprises a respective rectan9ular weld and dimple opening 298 ancl 300 opening radially outwards ~rom a -floor 301 deFined by the radially inboard surface of each of the slots 298 and 300 and extending axially in~ards from a front wall 302 to a rear wall in the form of flange 260, front wall 302 rising radially above slot 296. The terminals 246 ancl 248 are assembled into terminal insulating posts 242 and 2~4 prior to the molding of molded plug 170 by softly forcing the narrow length portion 2~8 and dimple 294 of each terminal throu~h the terminal slot Z06 until a rear surface 304 of each terminal abuts a~ainst flange 260 at which point dimple 294 axially clears front wall 302 of each openin9 298 and 300 to be a~equately restrained from axial movement therein. After the terminals 2L~2 and 244 are thus securely inserted into slots 298 and 300 the beginning and terminating ends 254 and 256 respectively oF the coil 250 are positioned in radial slots 306 and 308 throu~h flange 260 and then suitably electrically connected to narrow.ternlinal portion 288 in opening 29g and 300 as by spot ~elding at a ~/el~ point 310 intermediate each dimple 294 and the flange 260.
Radial slot 306 further commurlicates with a down-slot 312 Formed on the coil side of flan~e 260 to ~)rovide a suitable wire protection pocket extenclinc~
radially from the outer cylindrical surface of central portion 262 to the opening floor 301 to provide a suitable pocket therebetween to protect the beginning end 254 of the coil wire 250 from abrasion while winding the re-2S rnainder of the coil therenf.
. ~ . - . . . . . . .
~69()04 , MATERIALS
As has been indicated above with respect to actuator 140, armature 144 thereo-f comprises an armature element 150, a shoulder element i52, and a guide element 154, all of which integral with each other since they are being macle from the same piece of bar-stock material. So that the exhibits the proper electrolnagnetic response to the field createcl by coil 250 upon energization thereof, armature 144 is made from a ferro magnetic ~aterial such as 182 FM provided by the Carpenter Steel Corporation or 18-2 FM
provided by Universal Cyclops Uniloy Corporation. Moreover, to afFord a uniform coefficient of thermal expansion with armature 144 while at the same time avoiding cell-growing galvanic action with certain dissinlilar materials, actuator housing 90 is also made froln the same ferro magnetic material. Thin fuel brea~ up disc 60 is made of AISI type L corrosion resistant steel, and the tubular valve body 120 and tubular inlet connector 190 are each made from fully annealed steel AISI 12Ll~. The molded pluy is made from nylon-glass fiber (30%-40%) type 6 nylon reinForced, such material when molded shrinking about the flange 138 of valve body 120 and axial groove 198 to provide a tight seal aga;nst one side oF connectoi . flange 192. Moreover, the overall outer diameter.of fuel injection valve 10 is made materially smaller than that of conventional ~uel injection valves oF the type shown in the Prior Art Figure and the outer envelop PR
of which is shown dotted in about the outer envelope of the ~uel injection valve 10 shown in Figure 2.
~;9()~4 SUBSTANT~ALLY LAMINAR CENTRAL FUEL FLO~
.. Fuel injection valve 10 is speciFically designed to effect a smooth flow of Fuel from the inlet bore 212 thereof to the ball valve head and seat 148 and 86 respectively. When Fuel injection valve 10 is connected .-~lith fuel rail 22 to receive fuel under a 39 psig pressure and ~hen coil 250 is energized to pull actuator 140 back until shoulder 153 abuts a(Jainst ~asher 108 fuel flows into the inlet bore 212 and is there Fjltered by fuel inlet filter assembly 220. ThereaFter the fuel proceeds centrally ` through the ample bore of spring adjusting tube 200 and Flows axially into end openings 162 oF axially slots 158 o-F armature element 150. Progressing slightly in~lardly through passages 160 communicating slots 158 ~Jith central guide passage 156 the fuel is substantially straigten ancl smooth by the rel~aining length of the guide passage 155 the Reynold's number for the . flo~;J between the stem 146 and the actuator annulus 156 being calculated to 'be in the region oF 2900 Emerging from the mouth of the actuator 140~ the fluid -Flows between the stem 146 and the housin~ annulus 98 with a calculated Reynold's number of a stable laminar 1200 through the opening bet~;een the ball valve 148 and the housing annulus 98 where the Reynold's number jumps momentarily to approxima-tely 10 000. However with the :.
housing annulus 98 mergetl smoothly with the outer diameter oF the conical surFace 78 and with an actuatin~ stroke sufFicient to provide a 0.0~ to 0.15 mm clearance between the ball valve head 148 and the conical sur-Face 78 the flow therebetween drops to a low liminer Reynold's number oF 1900.
COMPARATIVE PERFORMANCE RESULTS
The superior performance oF the fuel inj~ction valve o~ the present . :~
invention may be better unders~ood as reference to Figures 6a 6b ancl 6c ~herein al'l the solid lines represent the reslllts obtained usiny an early developmental model oF the Fuel injection valve of the type shown in ~6 , Fi~ures 2-5 and wherein the dotted lines represent results obtained us;ny a conventional fuel injection valve of the ty~e shown ;n the Prior Art Figure. As sho~n in Figure 6a, the developmental fuel injection valve of the type disclosed herein provided noticeably better (lower) brake specific fuel consumption BSFC for all air fuel ratios up to 18.5:1 in the case of a 120 ft. lb. dynamometer load at 2,000 engine rpm or 19.5:1 in the case of a 70 ft. lb. load at 1600 rpm. As shown in Figure 6b, at an engine load of 70 ft. lb. at an speed of 1600 rpm the fuel injection valve of the present invention produces sli~h-tly lower carbon monoxide ; 10 (CO) emissions up to an air fuel ratio of 15:1, substantially lower hydro-carbon (HC) emissions out to an air ~uel ratio o-F 18:1 lower nitrogen oxide s ~rlOx) emission are generated above air fuel ratios of about 15~5 1a and the improvelnent becomes nlore pronounced and uniform at higher loads and - speeds where shown in Fi~ure 6c the fuel injection valve 10 of the present invention procluces uniFormly and substantiallY lower nitrogen oxide (NOx) emissions for all air fuel ratios, substantially lower hydro-carbon (HC) emissions, and slightly low carbon monoxide (CO) emissions.
RECAPITULATION
- As fully explained above, the fue1 injection valve 10 of the present invention is adapted to be sui~ably moun~ed on an internal combustion eng;ne 20 so as to be communicated with an intake passaye 18 thereof and comprises a tubular valve body 120 having a central s~epped bore 126 and 128 therethrough along a longitudinal valve body ax;s x-x. The valve body 120 comprises " annular hub means 124, C washer stop me~ns 108a and axially separated first and secondhold in means in the form of inwardly swageable lips 130 and 13~.
- The hub means 124 separate the stepped bore 126 and 128 into a coil and ~ inlet means cavity 129 and comprises the stop means pos-itionin~ surface 122 :,. .
.
and a first circumferential flux path surface 132 definin~ one side of a two sided radial air gap 1~3. The C washer stop means 108 ar~ positioned axially against the stop means positioning surface 122 of the h~lb means 124 and extend radially inwards therefrom so as to be abutable a~ainst radial surface 153 of ac-tuator shoulder element 152. The inlet connector means 190 are secured in the coil and inlet means cavity 129 by means of the in~lardly swageable lip 138 actin~ axially sn as to seat flan9e 192 against a seat 135 counterbored in the tubular body 120. The tubular inlet connec~
tor 190 comprises an outwardly extending flange portîon 192 intermediate an inlet tube portion 202 and an outlet tube portion 204. The inlet tube portion 202 is adapted to be connected as by fuel rail means 22 with a source of pressurized fuel and -together with the outlet tube portion 204 has a central fuel passage 194-212 therethrough along the valve body axis x-x.
. The outlet tube port;on 204 further comprises an annular terminating surFace 196 defining one side of a two sided axially air gap 168.
Fuel injection valve lO further comprises actuator housing means 90 secured in the actuator housing cavity formed by bore 126Of tubular valve body 120 and is held therein by the other of the valve body hold in means comprising inwardly s~ageable lip 130. The actuator housing means 90 has a central stepped-bore extending therethrough along the valve body ~.
axls x-x this stepped bore being separated by the valve seat and oriFice n-eans seat 96 into a fuel outlet bore portion 92 ancl an actuator bore portion 98. The fuel outlet bore portion 92 is terminated in fuei outlet . .
hold-in means in the form oF the inwardly swageable lip 94 and the actuator bore portion 98 has shoulder abutment means in the Form af lip 104 of counterbore 102 abuting against the valve body stop means in the form oF C washer 108. The valve seat and me-~eri~1g oriFice means 70 has an inlet side $0 and an outlet side 74 and comprises intermediate therebetween a centrally-located metering ori-Fice 76 the outlet end of which is con-~`
: tiyuous with an outlet surface 72 diverging towards the outlet sicle 74 and the inlet end of which is contiguous with two conticJuous inlet surfaces ~8 . and 86. Inlet surface 78 is conical and inlet surface 86 is partly spherical to define at their intersect;on the circular valve seat edge 88. Secured in the fuel outlet bore portion 92 against the outlet side 74 oF the valve seat and metering oriFice 70 are fuel outlet means in the form of the guide nozzle 50 and the thin fuel breakup disc 60. The fuel breakl~p disc - 60 colnprises a plurality of thin arcuate slots etched therethrough, each : slot havinJ a radial width of optimally not greater than 0.1 mm and an arcua~e length not less than twice this radial width. The number and lengths o-f tbe arcuate slots are selected to effect a total slot area whicll is at least 150~ of the area of the metering orifice 76.
The actuator means 140 comprises the armature means 1~4, and ball valve head 148, and the stem 146 and is loosely su~ported with a 0.007 to 0.035 ~m total clearance relative to the actuator bore portion 98 of actuator .. housing means 90 and are adapted to reciprocate axially therein along the valve body axis x-x between an open position and a closed position. The armature means 144 comprises a one piece guide element 15~, abutment element . :
. 152, and armature element 150. The abutment ele~ent lS2 is adapted to .; 20 abut a~ainst the valve body C washer stop means 108 to there establish the : open position of the armature. The armature element 150 comprises a second circumferential flux path surface 142 and a second transverse flux , .
path surface 164 cooperating with the first circum-ferentially flux surface 132 of hub 124 and the first transverse flux path sur~ace 196 of the outlet 25 tube portion 18~ to respectively define the otner sicles of the radial clir gap 1~3 and the axial air gap 168. The gu-ide element 154 of the armature ~eans 144 has an arcuate peripheral surface 166 loosely enga~ing .
the ac-tuator bore portion 98 so as to suFficiently center the actuator . nlealls to prevent the ~.lidth of the first and-second air gap 143 and 166 from ~: ~
.' ~ .
.
~ ~9~)04 bein~ less than first and second predeternlinecI air Japs. The guide element 154 and the armature element 150 of the armature means 144 also have a flo~l smoothing fue1 passage means 156~ 160, 158 and 162 therethrough .~ communicating with the central ;nlet passage 194 means 218 and 212 of the inle-t connector 190.
The valve head and stem means 1~8 and 146 have a free end terminated in the partly spherical valve head 148, a fixecl end terminated centrally in at bore 149 of armature element 150, and a stem length inter-mecliate this free end and fixed end telescoped by the portion 156 oF the central lq -Flow smoothing passage means. The stem 146 has a radial clearance in bore 156 as the partly spherical valve head 148 is guided by the partly spherical valve surface 186 to sea-t on the circular valve seat edge 88 and there establish the closed position oF the actuator means `140.
. Spring means in the form of the helical spring 214 are positioned between the fixed radial end 216 of the outlet tube portion 204 of the inlet connector 190 and the reciprocable terminating radial end 264 oF armature element 150 to normally biased the actuator mean$ 140 in a direction l~rom :~
the tubular inlet means 190 toward the valve seat and orifice means 70.
; Electromagnetic coi.l means 250 are positioned in the coil and , . .
inlet means cavity 129. Intermediate the valve body hub means 12~ and the inlet flange portion 192 and are operative when energized to establish . . a magneto motive force on the armature element i44 sufficient to overcome : the closing bias o-f spring 214 to move the actuator means 140 from its closecl position to its open position.
:~ .
,. , .
. . ,.
::`
.
~a~o~
CONCLUSION
Havin~ described several embodiments of the invention, it is understood that the specific terms and examples are employed herein ;n a descriptive sense only and not for the purpose of limitation. Other 5 embodiments of the invention, modiFication thereof, and alternat-ives thereto will be obvious to those skilled in the art and may be made with-out departing from my invention. I thereFore aim in the apended claims to cover the modifications and chan~es as I would in the true scope and spirit o~ my invention.
,. . :
.
.
. .
- 3~ -
Claims
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a fuel inlet assembly for a fuel injection valve (a) A fuel inlet connector comprising an inlet tube portion separated from an outlet tube portion by a radially extending flange portion, said flange por-tion having at least one terminal insulating post aperture therethrough between first and second flange sides; and (b) a coil and terminal assembly comprising a coil bobbin and a thin terminal, i) said coil bobbin having first and second radially extending flanges separated by an axially extending central portion positioned on said outlet tube portion, one of said bobbin flanges comprising a terminal insulating post extending axially therefrom through said aperture, said terminal insulating post having first and second ends separated by a thin slot extending the axial length of said post, said first end terminating at said one bobbin flange and said second end terminating outboard said second inlet connector flange side, said terminal post further comprising an oblong opening having a floor defined by said thin slot and a dimple locking wall extending radially outwards intermediate said first and second terminal post ends, and ii) said thin terminal having a narrow length portion received in said thin slot, said narrow length portion having a dimple across substantially the entire width thereof, said dimple being engaged by said dimple locking wall to restrain said thin terminal from axial movement in said thin slot.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA320,577A CA1069004A (en) | 1976-06-17 | 1979-01-31 | Electromagnetically operated fuel injection valve |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/697,173 US4030668A (en) | 1976-06-17 | 1976-06-17 | Electromagnetically operated fuel injection valve |
| CA273,500A CA1065707A (en) | 1976-06-17 | 1977-03-08 | Electromagnetically operated fuel injection valve |
| CA320,577A CA1069004A (en) | 1976-06-17 | 1979-01-31 | Electromagnetically operated fuel injection valve |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1069004A true CA1069004A (en) | 1980-01-01 |
Family
ID=27164958
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA320,577A Expired CA1069004A (en) | 1976-06-17 | 1979-01-31 | Electromagnetically operated fuel injection valve |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1069004A (en) |
-
1979
- 1979-01-31 CA CA320,577A patent/CA1069004A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4057190A (en) | Fuel break-up disc for injection valve | |
| US4101074A (en) | Fuel inlet assembly for a fuel injection valve | |
| US4030668A (en) | Electromagnetically operated fuel injection valve | |
| US5190221A (en) | Electromagnetically actuatable fuel injection valve | |
| EP1581737B1 (en) | Spray pattern control with non-angled orifices formed on a dimpled fuel injection metering disc having a sac volume reducer | |
| EP0918155B1 (en) | Fuel injection valve | |
| US7344090B2 (en) | Asymmetric fluidic flow controller orifice disc for fuel injector | |
| US6739525B2 (en) | Fuel injection valve | |
| US4520962A (en) | Magnetic fuel injection valve | |
| US4651931A (en) | Injection valve | |
| US6929196B2 (en) | Fuel injection valve and internal combustion engine mounting the same | |
| EP1392968B1 (en) | Spray pattern control with non-angled orifices in fuel injection metering disc | |
| US4653694A (en) | Intermittent type swirl injection nozzle | |
| JP2004514834A (en) | Fuel injection valve | |
| US20040056114A1 (en) | Spray pattern control with angular orientation in fuel injector and method | |
| US4917307A (en) | Fuel injector | |
| US6929197B2 (en) | Generally circular spray pattern control with non-angled orifices in fuel injection metering disc and method | |
| RU2059867C1 (en) | Solenoid nozzle | |
| GB2147949A (en) | Fuel injector for an I.C. engine | |
| CA1069004A (en) | Electromagnetically operated fuel injection valve | |
| US6851629B2 (en) | Fuel injection valve | |
| US6824085B2 (en) | Fuel injector | |
| US20040055566A1 (en) | Fuel injection valve | |
| JP2004511719A (en) | Fuel injection valve | |
| US7334746B2 (en) | Seat-lower guide combination |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |