Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF T~E INVENTION
.
Field of the Invention
T~e invention pertains generally to electromagnetic
injector valves and is more particularly directed to a
5 fast acting high flow rate injector valve with predictable
fuel spray pattern.
Electromagnetic fuel injection valves are gaining
wide acceptance in the fuel metering art for both multi-
point and single point systems where an electronic control
10 apparatus produces a pulse width signal representative of
the quantity of fuel to be metered into an internal com-
bustion engine. The injectors operate to open and close
pressuriæed fuel metering orifices leading to the air
ingestion paths of the engine by means of a solenoid actu-
15 ated armature responding to the electronic signal. Thequantity of fuel in~ected can then be precisely tailored
to the operating conditions of the engine by controlling
the fuel pressure, orifice size, and the duration of the
injector on time. Because of recent advances, electro-
magnetic injectors are becoming very precise in their
metering qualities and very fast in their operation. With
these advantages the electromagentic fuel injector valve
will continue to assist the advances in electronic fuel
metering which have improved economy, reduced emissions,
25 and aided the driveability of the internal com~ustion
engine.
Present electromagnetic in~ectors are usually di-
vided into two sections wherein the first section or the
stator means generates a magnetic force to control the
30 second se¢tion or the valve assembly which meters the
fuel. The two sections are operably coupled by a mag-
netically attractable armature physically connected to a
valve member. The valve member is normally biased against
a valve seat hy a closure spring in an off mode and opens
35 in response to the magnetic force.
Many of these injector valves have fuel under
pressure input ~o an entry port at the stator end of the injcctor.
The fuel then Elows by a generall~ concentric central
path through the body of the injector to the valve assembly.
These structures are usually termed "top feed" injectors.
Other injector structures have been made whereby lower pressures
oE input fuel may he made to the valve assembly end. ~hese
structures are usually termed "bottom feed" injectors. The
lower fuel pressure of the "bo~tom feed" injector reduces the
demand for a more expensive fuel pump and pressurizing system
which is necessitated in the "top feed" injector. Further, with
a "bottom feed" injector more flexible mounting procedures
may be used to advan-tage. It is known that such "bottom feed"
injectors can be utilized either in single point or multi-point
systems.
Examples of "bottom feed" injectors and their mounting
structures in two advantageous single point systems are found
in Canadian Patent Application Serial No. 328,901 filed on
~une 1, 1979 in the name of W. B. Claxton, and Canadian Patent
Application Serial No. 319,879 filed on January 18, 1979 in the
name of G. L. Casey; both of which applications are commonly
assigned to ~he assignee of the present application.
These injectors meter fuel by the length of time that
the valve mechanism is open and have a static fuel flow rate
dependent upon the size of the exit orifice. Relatively small
chan~es in the meterin~ orifice size can substantially change
the flow rate of the injector and thus the exit orifice size must
be precisely controlled. Claxton discloses a means by which the
- static flow rate of the fuel injector may be tailored after
assembly withou~ reboring the exit oriflce lf lt is off-sized.
~ ~till other injcctors have prior to this been expensivcly
_ remanufactured if the static flow rate is out of tolerance.
Even with this flow rate trim, the Claxton injector
after normal use may deviate from its calibrated static fuel
rate. Contaminan-ts from cvaporating fuel and foreign particles
in the air ~low may lodge in the e~it orifice of the injector
creating a modification to the flow rate. There is nearly
always some contamination build-up on the injector tip after
extensive use in hostile engine environment. This is
especially true in a low pressure "bottom ~eed" injector
where the force of the fuel through the exit may not be
enough to clean contamination and debris from the exit
orifice. It would, therefore, be highly desirable to obtain
the advantages of an injector trim and orifice metering while
not basing the injector flow rate on the exit orifice diameter
which can change with contamination.
Further, Claxton discloses a fast-acting valve which
can be dynamicall~ cycled into the millisecond range because
- of its low mass armature and needle valve combination. Another
low mass armature and the needle combination is illustrated
in a Canadian Patent Application Serial No. 328,649 filed on
May 30, 1979 in the names o~ J.C. Cromas, et al. and 'assigned
commonly to the assignee of the present application.
Although these injector valves have armature and
needle valve cor~inations which are particularly low in
mass and work well, they do require machining of the bearing
surfaces of their medial sections to produce the desired
results. High].y machined and smooth medial sections are
''` - 3 ~ '
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rec~ui.recl bec~use the bcaring surfaces must sllde
concentrica]ly to center the valve member into a conical
i
~'~ valve seat secure].y for sealing ~urposes.
Another fuel injector havi.n~ a low mass armature
: and val~e member combination is di.sclosecl in a U.S.
Patent 4,030,683 issued in the name of A. M. Kiwior on July 21,
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1977 and which is commonly assigned with the present
application. Kiwior discloses the use of a ball valve on
the end of a flexible stem mating with a conical valve
seat that has been coined. The armature and valve member
combination of this injector also utili2es bearing sur-
faces on the medial section for guiding purposes, although
it has a self-centering valve. Therefore, this injector
valve member and armature combination is fairly compli-
cated in structure primarily suitable for a "top feed"
injector. I~ would be desirable to provide an ~end feed"
injector with a low mass valve member and armature combin-
ation that i5 self-centering and does not necessitate
highly machined bearing surfaces on its medial section.
While all of the injectors discussed to this point
can be used in either single point or multi-point applica-
tions, it appears that single point applications will
become more and more prevalent~ One such single point
system gaining in popularity today requires an electromag-
netic injector that is mounted above the throttle blade of
the air ingestion path for the internal combustion engine.
When mounted in such a manner~ the most desirous spray
pattern for the injector is either full atomization or a
wide angled ~hollow conel' type of pattern. The hollow
cone ~pray pattern is termed such because much of the
injec~ed fuel is contained between an inner and outer cone
angle which have their apexes substantially at the point
of injection. The hollow cone pattern i~ advan~ageous in
above thro~tle blade injection because it does not wet the
sides of the throttle bore or the throttle plates ~ubstan-
tially and directs the fuel into the turbulent air betweenthe throttle blade and bore wall for excellent mix;ng and
atomization prior to engine ingestion~
One of the methods of generating a wide angle spray
i8 to generate a swirling or a vortex from the fuel
injector which spreads the fuel substantially uniformly
_5~ ~ 3 ~
: between the angles desired. In the application by Claxtona number of vortex generation techniques that are useful
to provide wide angle sprays are disclosed. Further, U.S.
Patent 3,241~168 issued to Croft illustrates a swirl gen-
eration means with a swirl chamber in an electromagnetic
fuel injector.
Croft and Claxton, however, generate wide angled
spray patterns that are difficult to control at lower
pulse widths for the injectorsO Both references have
swirl chambers that have relatively large residual volumes
when the injector is off When the injector is opened
there is a delay before the spray pattern is regenerated
and the vortex can be built up. Croft attempts to solve
this problem by using a complicated recirculation path to
continaully move fuel through the s~irl chamber when the
valve is closed. These injectors also meter fuel with
their exit orifices which, as has be~n explained before,
makes them subject to contamination problems. The valve
members of these injectors further extend into the valve
seats a substantial length and this extension tends to
disturb the vorte$ generated th~erein. The swirling fuel
tends to drag along the surfaces of the valve tip and lose
momentum.
It would, therefore, be desirable not only to provide
an injector with a swirl chamber haviny a mimimum residual
volume, but also one including an injector valve member
that does not extend substantially into the valve seat.
Since one would prefer an injector structure that
could be used in either single or multipoint injection and
a multiplicity of both types of designs are being prolif-
erated, it would be highly desirable to be able ~o control
the spray angle of the injector in the preferred hollow
cone pattern over a wide range. Generally, for single
point applications the farther away from the throttle
blade an injector is, the narrower the spray angle. Also,
3L~32~
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a very narrow spray angle can be utilized for most
multipoint applications. Wider spray angles can he used for
closer placement of the injector with respect to the throttle
blade in many other single point applications.
Wide control of the spray angle with a single common
structural element of the injector i9 diEficult for a low
pressure and high flow rate valve. One method of spray angle
control is illustrated in the application by Cromas~ et al.
where a protected pintle that has a deflection surface
perpendicular to the spray axis of the injector is used.
The distance away from the exit orifice and the diameter of
the deflection surface varies the spray an~le over a wide
range of injector pressures and flow rates. The deflection
surface, however, requires a very closely toleranced machining
operation and is relatively delicate in resulting structureO
It would be desirable to generate a controllable spray pattern
over wide ranges of pressures and flow rates without the
expense of the deflection pintle.
Accordiny to the present invention there is provided
an electromagnetic fuel injector having an energizable stator
means for controlling the moveme~t of a valve member of a
valve assembly to open and close the injector and thereby
meter fuel, the valve assembly having a valve housing with a
valve housing bore terminating with a valve seat which is
connected to an exit orifice~
A valve member is provided which includes a ball
valve reciprocally located in the valve housing bore and being
operable to obturate the exit orifice by sealing the valve
seat with the ball valve, the ball valve having a diameter
A ~
~3~
su~stantially e~uivalent to the valve housing bore such
that a housing interface is formed. A swirl chamber is
provided for imparting to the fuel flow exhausted ~rom the
exit orifice a swirl componen-t -that is tangential with
respect to the spray axis of the injector. r~eans is provided
for supplying fuel from a pressurized source to the swirl
chamber, including at least one entr~ metering orifice of a
predetermined size communicatiny fuel between the source and
the swirl chamber and positioned between the housing interface
and the valve seat.
Turning now to features of a specific embodiment of
the invention, the valve assembly may be provided with a valve
member comprising a ball valve that has at least semi-spherical
sealing surface and which is attached to a cup-shaped armature
means via a stem member. The valve member mates with a
conical valve seat which, preferahly, has been coined with a
larger semi-spherical surface to fo~m a self-seating valve
along a circular sealing ridge of the coinment. This eliminates
the need for the bearing surfaces on the medial section of the
valve member to maintain the valve concentric against the
seat. Thus, a low mass valve member which is self-centering
is provided which enhances the actuation time of the injector.
The stator means includes a coil assembly with a
central bore into which is mounted a core member containing an
adjustment screw. The core member is located adjacent across
an air gap from the cup-shaped armature of the valve assembly
and the adjustment screw cooperates with a closure spring
that biases the valve member against the valve seat. These
two members provide an adjustable lift and closure force for
the injector valve. The static flow of the entry orifices
can further be trimmed by the adjus-tment of the core member
when the lift is altered.
According to another aspect of a specific embodiment of
the invention, the valve member may be manufactured by resist-
ance welding a spherical ball valve to one end of a flexible
stem member and welding at the other end a cup-shaped magnetic
armature. The cup-shaped magnetic armature may be stamped as
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a cup or machined out of bar stock to produce a facile
member for connection to the stem. Preferably, the arma-
ture may be coated by a friction reducing substance where
it slideably contacts an armature guide bore o~ the valve
housing during its reciprocation.
According to still another aspect of the invention/
the spray pattern of the injector i5 controllable from a
wide angle hollow cone spray pattern to a narrow pencil-
like stream. The spray angle control is provided by posi-
tioning the fuel entry orifices with respect to a swirlchamber just upstream of the valve member and valve seat
interface. The positioning controls the tangential com-
ponent of Euel flow with respect to the axia:L component of
flow.
- lS The spherical valve and the conical valve seat co-
operate to provide a minimum residual volume swirl
~hamber. A swirl chamber with a minimum residual volume
will not vary the spray angle considerably over the wide
variations of injector pulse widths necessary for single
point injection. Thus, a very uniform spray pattern may
be maintained over a considerable speed range of the
engine. This will produce a more even fuel distribution,
less condensation and wall wetting.
The swirl chamber is assisted by the conical surface
of tha valve seat which acts as a vortex amplifier to
produce the desired spray angle. Since the ball valve
does not extend significantly into the volume between the
exit orifice and the conical valve seat, an amplification
of the swirling effect takes place as the fluid is accel-
erated into the narrowing area of the valve seat.
In a first preferred embodiment, the positioning ofthe entry orifices is four orifices tangential to the
swirl chamber. The spray angle of the injector is con-
trolled by controlling the ratio of the cross-sectional
areas of the entry orifices with respect to the exit
orifice.
- 9 -
Another embodiment is shown in which the spray angle
i5 controlled by modifying the positioning of the entry
orifices such that the direction o fuel entry is varied
between a tangenti~l entry and a radial entry. The spray
angle pattern is controlled by the amourlt of offset from
the tangential position that the entry orifice has been
moved.
Still another embodiment is shown where a combination
; of radial entry orifices and tangential orifices are used
:lO and whereby the spray angle is controlled by the rat.io of
the radial 10w component as compared to the tangential
flow component.
Yet another embodiment is shown wherein any one of
the first three embodiments may include an angular offset
from the horizontal to change the spray angle of the
injector.
These and other features/ advantages and aspects of
the invention will be more fully understood and better
explained if a reading of the detailed description is
undertaken in conjunction with the appended drawings
wherein:
'
DESCRIPTION OF THE DRAWINGS
,
FI5U~E l is a partially sectioned side-view of a
single point injection system with a high flow rate fast
acting electromagnetic injector valve constructed in ac-
cordance with the invention;
FIGURE 2 is a cross-sectional side-view of the elec-
tromagnetic injector valve illustrated in Figure l;
FIGURES 3 and 4 are sross-sectional top and side
views, respectively, of the injector valve housing illus-
trating the positioning of the entry ports for one embodi-
ment of the invention;
FI~URES ~ and 6 are cross-sectional top and side
views of an injector valve housing illustrating the posi-
tioning of the fuel entry ports for another embodiment of
the invention;
FIGURES 7 and 8 are cross-~ectional top and side
views, respectively, of an injector valve housing illus-
trating the fuel entry ports or still another embodiment
of the invention;
FIGURES g and 10 are cross-sectional side views of
alternate embvdiments of the valve member of the fuel
injector illustrated in Figure 20
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference now to Figuxe 1, there is shown an
electronic single point fuel :injection system for the
metering of fuel to an internal combustion engine. The
system comprises an electromagnetic injector valve 10
which is electrically corlnected by a pair of conductors
14tl6, of a connector 12 to a c:ontrol unit 18. A plur-
ality of ensine operating parameters can be input to the
control unit 18 including the speed or RPM at which the
engine is turning, the absolute presssure of the intake
: manifold (MAP), the temperature of the air ingested, (AIR
~EMP3, and the engine coolant tempera~ure (COOLANT TE~P)
by means of conventional sensors via input lines 15 a-d.
The injector 10 fits within an injector fuel
jacket 22 centrally located in a single air induction bore
34 of a throttle body 25 communicating with an intake
mani old 42 of the internal combustion engine (not shown).
For throt~le bodies with multiple air induction bores, an
injector per bore can be utili~ed. Air flow for engine
ingestion i~ regulated by a conventional throttle plate 30
which is rotatably mounted below the injector jacket 22.
Upon the sensing of the operatihg conditions of the
engine, the control unit 18 will calculat0 pulse width
electronic injection signals representative of fuel quan-
tity desired for injection and transmit them to the
injector 10 through connector 12, The injector opens and
closes relative to the leading and trailing edges of the
pulse signal respectively to meter fuel from the injector
jacket 22 into the incomminy air flow.
The fuel is metered in a wide ~pray angle pattern for
optimum mixture with the incoming air and delivery into
the intake manifold. The wide spray or hollow cone
pattern directs sub~tantially all of the injected fuel
between the area formed between the open throttle plate 30
and the bore 34.
Fuel under pressure is delivered to the injector
jacket 22 by a fuel inlet 20 and is circulated through the
interior of the injector jacket and thereafter to an exit
passage 24 where a pressure regulator 40 maintains the
systemic pressure constant. Spent fuel is returned to a
reservoir, such as a fuel tank, where it can be pumped
under pressure to the fuel jacket 22 once more.
The injector is sealed in the jacket by suitable
resilient means, such as an O-ring 28 at the bottom end of
the jacket, and an o-ring 26 resting against a shoulder at
the top end of the jacket. The injector 10 is restrained
in the jacket 22 against the O-rings by a spring clip 36
fi~edly positioned by by a screw 38. A fuel filter 27 may
be slip-fitted over the injector end to rest against the
lower O-ring 28.
Such a single point fuel injection system ~s shown is
particularly adaptable tv run a 2.2 liter engine having
four cylinders. By injecting twice every revolution or
180 of crankshaft movement, an air/fuel charge per each
cylinder firing i~ obtainedO The injection is preferably
35 made at a predetermined angle relative to an engine event,
-12-
~uch as ju~t prior to top dead center (TDC) of the
number 1 cylinder on the intake stroke, and thereafter
cylicly related to that point. The injection timing of
firing just before the opening of a particular intake
valve allows much o the uel and air charge to be trans-
ported to the particular cylinder injected. This reduces
condenæation and helps eliminate cylinder-to-cylinder
di~tribution errorsO
To inject a system as that described above, an
injector with a high single poin~ fuel rate of 400-600
cm3/min. and with a dynamic characteristic linear into the
one millisec range is needed. The invention provides ~uch
an electromagnetic injector valve 10 with an advantageous
construction.
With reference now to Figure 2~ the high flow rate
injector valve 10 is shown in cross~section to advantage
and comprises a tubular injector body 100 which may be
constructed from seamed or unseamed tubing which has been
cut to length. The injector body 100 is cold-formed at
each end to form a shoulder 101 with a radially offset rim
portion 102 at the front end and a shoulder 103 with
another radially offset rim portion 104 at the rearward
end. As the tubular body 100 is part of the magnetic
circuit of the injector, the material used is preferably
standard low carbon steel mechanical tubing. This
material provides excellent mechanical strength and
exhibits adequate magnetic permeability at low cost. ~he
body 100, as well as all other outside surfaces of the
injector valve 10, can be treated by conventional methods
for corrosion resistance and environmental hazards.
A front end cap 106 has a centrally bored cylindrical
body that is flanged to abut against the shoulder 101 and
i~ fixed in position by crimping or swaging the rim 102
against a bevel 108 machined on the flange. Similarly, a
rear end cap 110 compri~ing a centrally bored cylindrical
~ 7
-13-
body is flanged and abuts the shoulder 103 and iq a~ixed
thereat by deforming rim 104 to make with a bevel 112
machined in the flange of the cap.
Withln the chamber defined by the inner wall of the
injector body 100 and the inwardly facing surfaces of the
front end cap 106 and rear end cap 110, i5 a generally
elongated molded bobbin 114 wound with a plurality of
turns of magnet wire forming a coil 116. The coil 116 is
electrically connected to a set of terminal pins 120 (only
10 one shown) which rearwardly exit through an oval-shaped
aperture 122 in the rear end cap 110 and are protected by
a connector 118 integrally molded as part of the bob-
bin 114. The terminal pins 120 mate with suitable ter-
minals of the connector 12 to electrically connect the
injector to the control unit 18.
Bobbin 114 has a centrally located longitudinal
~ bobbin bore 124 which is substantially coaxial with a
- threaded rear end cap bore 126. A rod-shaped core mem-
ber 128 of a soft magnetic material is screwed into the
threads of the end cap bore 126 and extends substantially
the length of the bobbin bore. The core member 128 is
sloted at its thre2ded end 130 to provide for adjustment
of its extension into the bobbin bore 124. The adjustment
of the core member determines the initial air gap distance
and, hence, the lift of the valve. An adjustment
screw 132 is threaded into an internal bore of the core
member 128 to provide an adjustment of the valve closure
force and kime by means of a pin 140 moving against a
spherical ball member 136.
The internal bore of the core member 128 is sealed by
an O-ring 138 slipped over the pin 140 and sealing against
: the inner surface of the bore. The bobbin bore 124 is
hydraulically sealed at the internal face of the rear end
cap 110 by an O-ring 139 and the tubular body 100 is
hydraulically sealed at the front end cap 106 by an
O-ring 141.
-14-
Located in the central bore of the front end cap 106
is a single step dividing the bore into an armature guide
bore 142 and a mounting bore 1440 A valve housing 146 is
received in the mounting bore 144 until it abuts the
internal shoulder 145 formed at the step. The valve hous-
ing 146 is held in place by bending the front rim of the
mounting bore 144 over a chamfer in the valve housin~ 146.
The valve housing 146 has a centrally located longitudinal
valve housing bore 148 which communicates on one end with
the armature guide bore 142 and at the other end is ter-
minated with a conical valve seat 150 and a cylindrical
exit orifice 154.
According to one aspect of the invention reciprocal
in the valve housing bore 143 is a valve member 159 which
comprises a flexible stem 160 connected at one end to a
magnetically attractable cup-shaped armature 162 and at
the other to a ball valve 164. The ball valve 164 has at
least a semi-spherical sealing surface 165 which prefer-
ably mates against a coined portion of the conical valve
seat lS0. The valve seat 165 has been coined with a
larger spherical surface to alLow the ball valve 164 to
seat against the lower circul;3r edge of the coinment.
Alternatively, the valve seat lS0 may be conventionally
- lapped to where it forms a tight seal with the ball valve.
The spherical shape of the sealing surface 165 allows
the valve member to seat against the valve seat 150 in a
sure manner, even if the valve member closes slightly non-
concentric. There may al60 be some slight flexing of the
stem 159 to assist the seating of the ball valve 164 when
it closes. This produces a self-centering valve without
the necessity of the medial sections used in prior va~ves.
The cup-shaped armature 162 receives a closure
spring 137 within an inner spring mounting recess 147 of
the armature. Separating the armature 162 from the core
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member 128 is a working air gap maintained by the compres-
sion of the closure spring 137. The cup-shape of the
armature 162 reduces eccentric forces from the closure
spring 137 and provides an excellent magnetic path for
enhancing the opening time of the injector valve.
The armature slideably contacts the armature guide
bore 142 and is provided with a riction reduciny material
161 along the surface of contact. Alternatively, the
friction reducing material can be provided on the inner
surface of the armature guide bore.
The friction reducing material 161 allows the arma-
ture to be guided in the armature guide bore easily with
less of an air gap therebetween. A smaller air gap across
the sliding contact area of the armature side walls will
provide a higher flux through the armature and a greater
magnetic force across the working air gap during opening.
Preferably, the friction reducing material can also be
non-magnetic to aid the closing time and prevent the arma-
ture from sticking.
The closure spring 137 is compressed by the ball
member 136 against the spring recess 147 to produce a
clo~ure force on the valve member which can be adjusted by
turning adjustment screw 132. Torsional winding forces
are not generated during adjustment as the pin 140 will
turn on the ball member 136 and cause only axial movement
~ of member. Any tendency on the part of the closure spring
-~ to wind up will cause slippage against the surface of the
ball member and dissipation of the torsional force com-
ponen~.
Allowing fuel to enter a swirl chamber 151 of the
valve housing 146 are four tangentially located entry
orifices or ports 1490 The swirl chamber 151 is defined
when the valve 10 is closed by the area between the ball
valve 164 and the valve hou~ing bore beginning where the
valve seals against seat 150 and ending a~ its greatest
-16-
diameter where it interfaces the valve housing bore. When
the valve member 151 is in a closed position, the swirl
chamber is constrained to a very small volume, generally
crescent shaped in cross-section. The residual fuel held
5 in this small area will not substantially affect the spray
pattern generation at very small pulse widths.
The configuration including the spherical shape of
the ball valve 164, the cylindrical shape of valve housing
bore 148, and the conical shape of the valve seat 150
contribute to the provision of a minimum volume swirl
chamber. This configuration provides a facile structure
where the entry ports can be positioned between the valve
seal and the interface at the diameter of the ball valve
and valve housing bore 148, The ball valve 164 because of
-15 its geometric shape closes the swirl chamber at two places
and can be readily manufactured to acceptable tolerances
for these interfaces. When the valve is open, the lower
spherical surface of the ball valve becomes the top of a
larger swirl chamber. This allows the swirl chamber to
grow in volume as the injector opens.
In operation, when current in the form of an injec-
tion signal from the control umit 18 is supplied to the
terminal pi~s 120 from the cclnnector 12~ and thus~ to
;coil 116, a magnetic field is set up through the core
member 128, the rear end cap 110, the injector body 100~
and the front end cap 106 to attract the sofk magnetic
material of the armature 158 across the air gap to abut a
nonmagnetic shim 135 on the face of the core member. The
shim 135 aids the closing time of the valve by maintaining
a minimum working air gap during energization.
;When the magnetic attraction overcomes the force of
the closure spring, the valve member will be lifted away
from the valve seat and fuel will be metered by the entry
orifices 149 until the current to the terminal pins 120 is
terminated and the closure spring force overcomes the
collapsing magnetic force to seal the valve once more.
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The tangential vorticity imparted to the fuel begins
to generate a vortex in the swirl chamber 151 when the
valve i~ open. The swirling fuel is then accelerated by
vortex amplification through the conical valve seat and
ejected from the valve by means of the wide exit ori-
fice 154.
The entry orifices, which are of controlled diameter
for metering, can be preci ely sized by ballizing the pas-
sageways with a predetermined size of hardened spherical
10 die. ~s the entry oriices are of a predetermined size,
the metering of the fuel is substantially accomplished by
the entry orifices and contamination of the exit orifice
will not drastically change the static flow rate as in
previous valves~
::~ 15 After assembly, the lift and air gap can be adjusted
by turning core member 128 and the closure force adjusted
by turning adjustment screw 132~ The two adjustments will
complement each other to calibrate the static and dynamic
~:~ fu~l flow and can thereafter be locked by a potting com-
20 pound 121.
Returning for an instant to Figure 1, the spray
pattern or angle of fuel of the exhaust flow is a function
of the tangential component, Tc, of the fuel flow as com~
pared to the axial component, Ac, of the fuel flow. The
resultant component, Rc, will be the direction of fuel
spray angle. The w~dth of the angle will depend on the
magnitude of the exhaust velocity as measured by resultant
~: component Rc. Therefore, maximizing the tangential com-
~: ponent T~ and the resultant exhaust velocity will maximize
the spray angle A measured from the vertical. Minimizing
~: these parameters will conversely minimize the spray
: angle A.
With attention now directed to Figure 3, there is
: shown cross~sectioned top and slde views of an embodiment
of the valve housing 146 which has a vortex generating
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means creating a wide angle spray pattern for injection.
In this embodirnen~ ~ vortex of fuel is generated by four
tangentially-located, precisely-sized entry orifices
149 a-d. The positioning of these entry orifices at the
extreme diametral spacing generates a maximum tangential
or swirl component in the pressurized fuel as it enters
the swirl chamber 151. The tangential velocity of the
fluid is then further increased as it travels through the
conical valve seat ahead of the exit orifice 154. The
conical valve seat, because of the non-extension of the
ball valve into the seat area, allows a wide area for
vortex amplification.
There are two factors, as illustrated in Figure 3,
which the invention utilizes to control the tangential
flow component Tc and the maqnitude of the exhaust
velocity. The primary factor is input fuel velocity with
respect to both magnitude and direction. By varying the
diametral spacing, Dl, of the entry ports 149 a-d with
respect to the axis A-A of the valve~ the tangential
versus radial component of the input velocity can be
varied, and hence the magnitude of the tangential output
component Tc, which is directly related thereto. Adjust-
ing the spacing between the spray axis A~A and the axis of
the entry port along a diameter perpendicular to the port
axis is the same as varying the entry direction of the
- fuel between tangential ~maximum diametral spacing1 and
radial (minimum diametral spacing).
The magnitude of the input fuel velocity is a func-
tion of the cross-sectional area of the entry orifices for
a given pressure. Generally, the greater the pressure
drop across each entry port, the higher the input velocity
will be. This is consistent with the aspect of the inven-
tion which provides for the metering of the fuel to be
substantially accomplished by the entry ports. Since to
obtain a significant pressure drop and high input velocity
--19--
the ports must be small, a plurality of entry ports are
used to generate the desired static flow rate by multiply-
ing the flow for each individual port times the number of
ports.
In the preferred embodimentl however, not all of the
fuel pressure is dissipated across the entry ports asl
according to another aspect of the inventionl the static
flow rate is controllable by the lift of the valve. Thus,
the ball valve and seat interface create a restriction
which is adjustable and can be used to adjust the static
fuel flow rate~ No pressure drop is needed across the
exit orifice 154 and a wide exit is used.
It has been determined in a low press~re "bottom
feed" injector having an input fuel pressure of approxi-
mately 15 PSI that an advantageous configuration is to
dissipate most of the pressure across the entry ports~ but
to allow a pressure drop across the ball valve and seat
- inSerface that can be used to vary the static flow rate
approximately 10~.
The sécond factor that influences the tangential com-
ponent Tc and exhaust velocity .is the gain of the vortex
amplifier or the conical surface oE valve seat 150. By
the conservation of momentum, theoretically, as the radius
ratio R2/Rl (input compared to output) increasesl the ~an-
gential velocity component of a non-viscous fluid will
increase in a manner functional:Ly related to this ratio.
Thus~ fuel input into the swirl chamber 151 will have its
tangential component amplified. All fuels, however, have
viscosity which wlll provide a damping effect on the
vortex amplification which al50 increases with velocity
and radius ratio. Therefore/ for a real fluid there is
generally some radius ratio of vortex amplifier which will
maximize the gain of the vorticity. For a single point
valve, such as that illustrated and used for fuel injec-
tion, it has been empirically demonstrated such a ratio isapproximately 4:1.
~3~
-20~
With the foregoing in mind, one embodiment of the
invention can utilize the ratio of the d;ameter of the
entry orifices to the diameter of the exit orifice to vary
the exhaust spray angle. In this embodiment the magnitude
of the input velocity can be varied with respect to the
gain of the vortex amplifier to regulate the tangential
component Tc and axial component Ac. Preferably, the
~: input velocity direction is fixed at the maximum diametral
spacing.
In another embodiment, the gain of the vortex ampli-
fier is fixed and likewise the magnitude of the input
velocity, The tangential component Tc may then be con-
trolled by varying the diametral spacing of the entry
orifices to ad~ust the resultant direction of the input
velocity. This, as stated before, directly modifies the
ratio of the radial to tangential components of the input
v~lo~ity.
Another embodiment of the invention for varying the
: spray angle of the injector is illustrated in Figures 5
and 6 which show the injector valve housing 146 in side
and top cross-sectional views. The entry orifces 178 and
180 in this embodiment are p:rovided tangential to the
vortex amplification means and spaced at a maximum dia~
~: metral spacing with respect to the swirl chamber. Addi
tionally, two radial entry orifices 184 and 18? are
provided to produce a component of fluid entering the
injector substantially directed toward the axial center of
~ the exit orifice 154. The spray angle for this embodiment
- will again be a function of the ratio between the tangen-
tial and radial flow components.
Figures 7 and 8 illustrate still another embodiment
- for changing the spray angle of the injector where cross-
sectional top and side views of the injector valve housing
146 are shown~ Entry orifices 186,188,190 and 192 are
provided tangen~ial to the vortex amplification means but
-21-
are canted at an angle ~ from the horizontal to provide
a vertical component to the entry of the fuel flow. The
vertical offset has the same effect as the mixing of the
radial and tangential component flow in the other plane.
That is to say, that the spray angle will additionally be
a function of the vertical component to the horizontal
component.
By any of these methods, or a combination thereof,
- the spray angle for the injector can be adjusted from
nearly a solid, pencil-like æ~ream to a hollow cone spray
pattern having an included angle exceeding 90.
All o~ the entry orifices illustrated in Figures 2-8
can additionally include counterbores on their source side
to allow the smooth entry flow of fuel therein. A
counterbore will tend to increase the orifice flow
coefficient such that higher input velocities with lower
pressure drops may be obtained.
Alternate embodiments of t:he valve member 159 are
illustrated in Figures 9 and 10 where each generally com-
prises a generally cup-shaped armature means connected by
means of a f lexible stem member to a ball valve. In
: Figure 9 an armature means 200, which is machined from bar
stock of a magnetic material, is overlayered with a
friction reducing material 202. The armature means 200 is
thereafter connected to a flexible skem member 204 which
in turn is connected to valve 206 to form a val ve member.
The connections are preferably made by resistance welds
- 203 and 205.
Likewise, in Figure 10, an armature means 208 is con-
nected to a flexible stem member 212 which is connected toa ball valve 214 by means of resistance welds 209 and 213,
respectively. The armature means 210 in this embodiment
is stamped from a sheet into the cup-shape and thereafter
coated with a friction reducing material 210. It is noted
in thls embodiment that the friction reducing material 210
2(~ '7
overlayers thc armature where it will contact the core member
128 (Figure 2). Choosing the material 210 for this implementation
to be non-magnetic wili eliminate the need for the non-magnetic
shim 135.
i The layer of friction reducing material described
for the various preferred embodiments throughout the specifi-
cation may be selected from the group comprising polytetra-
flourethylene, sold under the trade mark T~LFON, electro].ess
nickel, copper with a nickel or tin overcoat, or similar materials.
While the preferred embodimentsof the invention have
; been shown, it will be obvious tothose skilled in the art
that modifications and changes may be made to the disclosed
- system without departin~ from the spirit and scope of the invention
~ as defined by the appended claims.
:;`
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~mt~ -22-
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