U.S. patent number 3,785,627 [Application Number 05/281,891] was granted by the patent office on 1974-01-15 for charge forming apparatus.
This patent grant is currently assigned to Borg-Warner Corporation. Invention is credited to Irving H. Hallberg, John J. Tuzson, James R. Vaughn.
United States Patent |
3,785,627 |
Tuzson , et al. |
January 15, 1974 |
CHARGE FORMING APPARATUS
Abstract
Charge forming apparatus for metering fuel in which a stream of
induction air impinges upon a stream of liquid fuel for changing
the shape thereof. Fuel is stripped from the reformed liquid stream
for dispersion into the air stream. Single or multiple fuel streams
may be employed. The apparatus avoids the use of a float thereby
facilitating up draft, side draft, or down draft mounting. One
embodiment eliminates the choke plate providing a compact structure
having a short air induction passage.
Inventors: |
Tuzson; John J. (Evanston,
IL), Hallberg; Irving H. (Des Plaines, IL), Vaughn; James
R. (Des Plaines, IL) |
Assignee: |
Borg-Warner Corporation
(Chicago, IL)
|
Family
ID: |
23079201 |
Appl.
No.: |
05/281,891 |
Filed: |
August 18, 1972 |
Current U.S.
Class: |
261/36.2;
261/DIG.39; 261/71; 261/39.5; 261/41.5 |
Current CPC
Class: |
F02M
7/106 (20130101); Y10S 261/39 (20130101) |
Current International
Class: |
F02M
7/10 (20060101); F02M 7/00 (20060101); F02m
007/14 () |
Field of
Search: |
;261/36A,DIG.39,71,4R,41D,41B,39R,39D,DIG.69 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
246,489 |
|
Jan 1927 |
|
GB |
|
740,036 |
|
Nov 1955 |
|
GB |
|
Primary Examiner: Miles; Tim R.
Attorney, Agent or Firm: Donald W. Banner et al.
Claims
What is claimed is:
1. Charge forming apparatus including a body member having fuel
passage means and an air induction passage defined therein, and
including an adjustable throttle member arranged for regulating the
rate of air flow through said induction passage,
said fuel passage means adapted for circulating a fuel stream
through said body including a fuel channel extending across said
air induction passage,
said fuel channel including a gap portion facing substantially
upstream of said air induction passage permitting impingement of an
air stream in said induction passage upon a fuel stream in said
fuel channel, the configuration of said gap portion defining
modulating surface for regulating the shape of the fuel stream in
said channel, said fuel channel including stripping surface
arranged and disposed for deflecting fuel from said channel into
said induction passage.
2. Charge forming apparatus according to claim 1 in which said fuel
channel comprises a hollow member extending across said air
induction passage having longitudinally extending slotted portions
formed in both the upstream and downstream side thereof, said
upstream slotted portion permitting impingement of air flowing in
said air induction passage upon a stream of fuel in said channel,
and said downstream slotted portion including an endwall edge
portion providing stripping surface for deflecting fuel into said
air induction passage.
3. Charge forming apparatus according to claim 1 in which said fuel
channel comprises a hollow member extending across said air
induction passage having a longitudinally extending slotted portion
formed on the upstream side thereof defining a pair of laterally
spaced wall edge portions and an end wall edge portion, said
laterally spaced edge portions permitting an increase in width of a
stream of fuel in said channel in response to impingement thereon
of air flowing in said air induction passage, and said end wall
edge portion providing stripping surface for deflecting fuel into
said air induction passage.
4. Charge forming apparatus according to claim 3 including an
adjustable sleeve member overlapping said slotted portion of said
channel hollow member, said sleeve member being movable for
modifying the configuration of said slotted portion exposed in said
air induction passage.
5. Charge forming apparatus according to claim 4 in which said
sleeve and slotted portions are longitudinally movable relative to
each other for modifying the length of the slotted portion exposed
in said air induction passage.
6. Charge forming apparatus according to claim 4 in which said
sleeve and slotted portions are rotatable relative to each other
for modifying the lateral extent of the slotted portion exposed in
said air induction passage.
7. Charge forming apparatus according to claim 3 in which said
laterally spaced wall edge portions extend at an angle with respect
to the upstream side of said hollow member.
8. Charge forming apparatus according to claim 1 in which said fuel
channel comprises a nozzle member and a receiver member in flow
alignment with each other, said nozzle member permitting
impingement of air in said air induction passage upon fuel in said
channel, said receiver member including stripping surface arranged
for deflecting fuel into said air induction passage.
9. Charge forming apparatus according to claim 8 in which said
nozzle member includes a portion extending telescopically within
said receiver member.
10. Charge forming apparatus according to claim 9 in which said
nozzle and receiver members are mounted for adjustment movement
relative to each other permitting modification of the configuration
of said gap portion.
11. Charge forming apparatus according to claim 1 in which said
fuel channel is disposed in said air induction passage upstream of
said throttle member, said body including an auxiliary air bleed
passage communicating with said air induction passage between said
fuel channel and said throttle member.
12. Charge forming apparatus according to claim 11 including a
choke member disposed in said air induction passage upstream of
said fuel channel, said auxiliary air bleed passage having an inlet
end communicating with said air induction passage between said fuel
channel and choke member and an outlet end communicating with said
air induction passage between said fuel channel and said throttle
member.
13. Charge forming apparatus according to claim 1, said fuel
channel being disposed upstream of said throttle member, said
apparatus having a selectively operable fuel enrichment device
comprising an auxiliary fuel conduit extending across said air
induction passage including an elongated slotted portion formed in
a wall thereof, and a rotatably mounted cover member partially
enveloping said conduit, said cover member having control means
extending externally of said body whereby said cover member is
capable of rotation for selectively uncovering said slotted portion
of said conduit.
14. Charge forming apparatus according to claim 1, said fuel
channel having a gap portion configuration selected for providing a
portion of a desired fuel requirement, said apparatus including
additional fuel channel means having a gap portion configuration
selected for providing another portion of said fuel requirement.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to apparatus for dispersing liquid
into an air stream and more particularly to apparatus for
dispersing fuel into an air stream for forming a combustible
mixture.
2. Description of the Prior Art
The prior art includes aspiration devices such as carburetors and
jet receiver apparatus for inducing fuel into an air stream.
Carburetors typically employ a venturi section in an air induction
passage which creates a pressure drop across a metering orifice for
aspirating fuel into the air stream. An objection to such devices
arises from the limitation on air flow through the restriction at
the venturi throat. Another objection arises from the difficulty
encountered in calibration of the metering orifice. Many prior
carburetors employ floats which are sensitive to tilting, and many
require an accelerating pump to supplement fuel delivery.
In one form of jet receiver apparatus, fuel deflection is carried
out in an auxiliary chamber by means of a fluid amplifier. An
objection to such an apparatus arises from the added fluid
amplifier system. In other forms of jet receiver apparatus, the
fuel stream is diverted from the receiver during timed intervals
such as by means of ultrasonic vibration or by an auxiliary air
blast. Objections to such prior jet receiver apparatus arise from
the auxiliary apparatus required to regulate fuel pressure and/or
the duration and repetition rate of jet deflection intervals.
SUMMARY OF THE INVENTION
An object of the present invention is to provide improved charge
forming apparatus in which fuel is dispersed from a fuel channel
into an air stream in accordance with changes in shape of the fuel
stream resulting from impingement of the air stream on the fuel
stream;
Another object of the invention is to provide charge forming
apparatus which avoids the use of a float thereby facilitating
inclined operation;
A further object of the invention is to provide charge forming
apparatus in which the proportions of fuel in the mixture are
regulated by the configuration of a cap in the fuel channel;
A still further object of the invention is to provide charge
forming apparatus having a gap in the fuel channel in which the
configuration of the gap is subject to adjustment for regulating
the rate of fuel dispersion into an air stream; and
An additional object of the invention is to provide charge forming
apparatus having excess fuel available in the air induction passage
for responding to increases in fuel requirement;
these and other objects and advantages of the invention will become
more evident through consideration of the drawings and following
description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevation view of one embodiment of charge forming
apparatus according to the present invention;
FIG. 2 is a section elevation view taken along the line 2--2 of
FIG. 1 showing an arrangement of fuel channels in the air induction
passage;
FIG. 3 is a section view taken along the line 3--3 of FIG. 1
showing fuel passages and channels;
FIG. 4 is a fragmentary section view taken along the line 4--4 of
FIG. 1, showing an auxiliary air passage;
FIGS. 5, 5a, 6, 6a, 7 and 7a are fragmentary views to enlarged
scale showing gap configurations of fuel channels employed in the
embodiment of FIGS. 1 through 4;
FIGS. 5b, 6b, and 7b are graphical representations of flow
characteristics typical of the fuel channel gap configurations
shown in FIGS. 5, 5a, 6, 6a, 7 and 7a;
FIG. 8 is a graphical representation further illustrating typical
fuel delivery characteristics of the embodiment of FIGS. 1 through
4;
FIGS. 9, 9a and 9b are fragmentary views to enlarged scale showing
an alternate form of fuel channel and gap configuration;
FIG. 9c is a graphical representation of flow characteristics
typical of the alternate form of fuel channel gap configuration
shown in FIGS. 9, 9a and 9b;
FIGS. 10, 10a and 10b are fragmentary views to enlarged scale
showing an alternate form of fuel channel and gap configuration
included in the embodiment of FIGS. 11 and 12;
FIG. 10c is a graphical representation illustrating flow
characteristics typical of the fuel channel of FIGS. 10, 10a and
10b;
FIG. 11 is a section elevation view taken along the line 11--11 of
FIG. 12 showing another embodiment of the invention employing a
fuel channel as shown in FIGS. 10, 10a and 10b;
FIG. 12 is an elevation view of the embodimnt shown in FIG. 11;
FIG. 13 is an elevation view of another embodiment of the invention
characterized by a short air induction passage, and a fuel
enrichment means as shown in FIG. 17 which permits the elimination
of a choke plate;
FIG. 14 is a section view taken along the line 14--14 of FIG. 13
showing fuel passages and channels;
FIG. 15 is a section view taken along the line 15--15 of FIG. 13
showing the fuel enrichment means in greater detail;
FIG. 16 is a semi-schematic section elevation view taken along the
line 16--16 of FIG. 13; and
FIG. 17 is an enlarged section view of the fuel enrichment means
taken along the line 17--17 of FIG. 15.
DETAILED DESCRIPTION OF THE INVENTION
Referring now in more detail to the drawings and more particularly
to FIGS. 1 through 4 thereof, the reference character 20 indicates
charge forming apparatus according to the present invention. A body
21 includes an air induction passage extending therethrough defined
by the inlet or upstream end portion 22, the mid portion 23 and the
outlet or downstream end portion 24. If desired, the air inlet
passage may be formed with a constant diameter throughout its
length, however, as shown in the drawings the diameters of the
three passage portions differ, having been chosen to provide
substantially equal flow areas in view of the areas occupied by the
fuel channels and the choke and throttle plates and shafts.
A choke plate 26 and choke shaft 27 are mounted in the inlet or
upstream end portion 22 of the air induction passage. The shaft is
rotatably mounted in body 21 and secured to lever 28 by means of
which choke plate 26 can be turned to obstruct the air induction
passage.
A throttle plate 36 and throttle shaft 37 are mounted in the outlet
or downstream portion 24 of the air induction passage. Shaft 37 is
rotatably mounted in body 21 and secured to lever 38 for turning
the throttle plate to regulate the rate of flow of air through the
air induction passage. The portion of body 21 adjacent the inlet or
upstream end 22 of the air induction passage is provided with a
boss portion 29 for receiving an air cleaner or filter device not
shown in the drawings. The opposite portion of body 21 adjacent
outlet end 24 of the air induction passage is provided with
mounting flanges 31, 31 for connection to the inlet manifold of an
internal combustion engine not shown in the drawings. An auxiliary
air passage 32, 33, 34 extends in flow parallel with respect to mid
portion 23 of the air induction passage. If desired, the body 21
can be provided with a fitting 39 which is arranged to provide a
manifold vacuum signal for connection to components used in clean
air systems.
Body 21 is provided with a system of internal fuel passages
including the fuel inlet 41, inlet passages 42, 43, outlet passages
44, 46 and outlet port 47 interconnected by fuel channels 48, 49
and 51. The fuel channels are provided with surface interruptions
defining gap portions 52, 53, 54 facing upstream toward the inlet
end 22 of the air induction passage. As will be described more
fully hereinafter, the gap portions of fuel channels 48, 49, and 51
are provided with different configurations for responding to idle,
mid range and wide open throttle operation.
Idle fuel channel 51 includes nozzle 56 and receiver 57 mounted to
define the gap zone 54 off center of air passage 23. Nozzle 56 is
secured to a fitting 62 which intersects inlet fuel passage 43
between a pair of spaced seals 63, 63. Fitting 62 includes an
aperture 64 and groove 66 for conducting fuel from passage 43 to
nozzle 56. Fitting 62 is secured in a bore 67 in body 21 by means
of a retainer ring 68 and set screw 69, the retainer ring securing
the fitting against displacement from passage 43 and the set screw
securing the fitting and nozzle 56 against rotation with respect to
the upstream end 22 of the air induction passage.
Receiver 57 is secured to a second fitting 71 which includes an
aperture 72 and groove 73 for conducting fuel from the receiver to
outlet passage 46. A seal 74 is arranged to prevent leakage along
the bore 76 in body 21. FItting 71 includes a threaded portion 77
and a slot 78 by means of which receiver 57 can be moved toward and
from nozzle 56 for adjusting the length of the gap zone 54. A lock
nut 79 is provided for securing receiver 57 against displacement
from its adjusted position.
As shown more clearly in FIGS. 5 and 5a, nozzle portion 56 and
receiver portion 57 are formed of hollow tubing and arranged in
flow alignment with each other. Nozzle portion 56 is beveled on its
upstream side and spaced from receiver 57 to provide the
interrupted zone or gap portion 54. The configuration of the inner
surface 58 and the oval ring surface formed by beveled wall portion
59 provide a fuel stream modulating surface by which a jet or
stream of fuel in nozzle 56 is flattened and widened in the gap or
interrupted zone 54 by impingement thereon of the air stream. The
end surface 61 of receiver 57 provides stripping surface for
deflecting fuel from the margins of the stream and dispersing the
stripped portion of fuel into the air stream. The angularity and
shape of the beveled surface 59 facing the upstream end 22 of the
air passage, the length of gap portion 54 and the inner diameter of
receiver 57 are selected to regulate the amount of fuel dispersed
into the air stream. While the angle of the beveled surface 59 and
the inner diameter of the receiver are fixed values, the nozzle may
be slightly rotated with respect to the air passage and the
receiver may be moved toward and from the nozzle to provide
adjustment of the gap configuration for regulating the fuel
delivery characteristics of the channel.
Mid range fuel channel 49 is mounted in body 21 in a manner similar
to the mounting of idle channel 51. Nozzle portion 81 of channel 49
is secured in a fitting 83 which includes an aperture 84 and groove
86 disposed in fuel inlet passage 42 permitting flow of fuel from
the inlet passage through the fuel channel. Seals 87, 87 are
arranged on opposite sides of passage 42 to prevent leakage between
the fitting and the wall of bore 88. Fitting 83 is secured in bore
88 by retainer ring 89 and set screw 91.
Receiver portion 82 of fuel channel 49 is secured to a fitting 92
which includes an aperture 93 and groove 94 permitting fuel flow
from receiver 82 to outlet passage 44. Fitting 92 includes a
threaded portion 96 for adjustment of receiver 82 with respect to
nozzle 81 permitting regulation of the size of the gap portion 53.
A lock nut 97 provides means for securing receiver 82 against
displacement from its adjusted position.
As shown in FIGS. 6 and 6a, the end of nozzle member 81 is
telescopically received in receiver member 82 such that the gap
portion 53 occurs in the upstream surface of the channel but not in
the downstream surface. The beveled surface 117 and inner surface
118 of nozzle 81 provide fuel stream modulating surface by means of
which the shape of a stream of fuel in nozzle 81 is changed by
impingement thereon of a stream of air in the air induction
passage. Impingement of air on fuel in the gap zone 53 causes the
fuel stream to become flatter and wider such that the lateral
margins of the fuel stream extend outwardly of or strike the
stripping surface formed by end wall 119 of receiver 82. Thus
portions of the fuel in the fuel stream are dispersed into the air
stream.
High range fuel channel 48 includes a nozzle member 98 and receiver
member 99 having a gap portion 52. Nozzle 98 is secured to fitting
101 which includes aperture 102 and groove 103 intercepting fuel
passage 42 permitting flow of fuel from the inlet passage to the
nozzle. Fitting 101 is received in bore 104 of body 21 and secured
therein by retainer ring 106 and set screw 107. Seals 108, 108 are
employed to prevent leakage along the surface of bore 104. Receiver
member 99 is secured to fitting 109 which includes aperture 111 and
groove 112 permitting fuel flow from the receiver to outlet passage
44. Fitting 109 includes a threaded portion 113 by means of which
the receiver can be moved longitudinally in bore 114 for adjusting
the position of receiver 99 with respect to nozzle 98 which in turn
results in adjustment of the length of gap portion 52. A lock nut
116 is provided for securing fitting 109 and receiver 99 against
displacement from the adjusted position. As shown more clearly in
FIGS. 7 and 7a, the end of nozzle 98 has a beveled surface 121
which together with inner surface 122 provide modulating surface in
gap zone 52 permitting a change of shape of a stream of fuel in the
channel. The end 123 of receiver 99 provides stripping surface for
deflecting fuel from the channel into the air induction
passage.
Fuel channels 48, 49 and 51 are shown to enlarged scale in FIGS. 5,
5a, 6, 6a, 7 and 7a wherein differences in the gap configuration
are illustrated in more detail. Fuel dispersion characteristics
typical of channels 48, 49 and 51 are illustrated graphically in
FIGS. 5b, 6b and 7b.
The idle fuel channel 51 as shown in FIGS. 5 and 5a is constructed
to have a relatively small flow area in the nozzle portion 56
sufficient for idle fuel and light load requirements of an engine
with which the apparatus is to be used. The nozzle 56 and receiver
57 are spaced apart at the upstream and downstream walls providing
a gap 54. The gap 54 permits a stream of fuel in the nozzle to
become flatter and wider as a result of the impingement thereon of
air flowing in the air induction passage. An increase in gap length
increases sensitivity to low air flow rates up to a point at which
substantially the entire stream of fuel is deflected from the
receiver.
The line 124 of FIG. 5b illustrates dispersion characteristics
typical of idle channel 51. An example of channel 51 was
constructed in which the internal diameter of both the nozzle and
receiver were 0.032 inches, the angle of surface 59 was thirty
degrees with respect to the downstream side of the nozzle, and the
gap length was approximately 0.100 inches. A fuel channel
constructed as above was tested on flow bench calibration equipment
and was found to be capable of flowing approximately 127 cubic
centimeters of fuel per minute. At no air flow, the jet or stream
of fuel issuing from the nozzle portion expanded in the gap zone
and approximately 20 cubic centimeters of fluid per minute was
stripped from the stream and deflected into the air induction
passage by the stripping surface 61 of receiver 57. As the air flow
rate in the air induction passage was increased, the fluid stream
became flatter and wider in the gap zone such that increasing
amounts of fluid were stripped from the stream and deflected into
the air passage until an air flow rate of approximately 80 cubic
feet per minute was reached at which point the entire fluid stream
of 127 cubic centimeters per minute was deflected below receiver 57
into the air induction passage. In the example channel, the inner
diameter of the receiver and the gap length were selected to
provide a fluid dispersion rate for supplying the idle fuel
requirements and a portion of the light load fuel requirement of a
six cylinder internal combustion engine. In general, a decrease in
the inner diameter of the receiver or an increase in the gap length
results in an increase in initial fuel dispersion. Conversely, a
larger receiver inner diameter or a shorter gap length tends to
decrease initial fuel dispersion.
The line 126 of FIG. 6b illustrates the flow characteristics of an
example embodiment of intermediate channel 49. In the example
embodiment, the inner diameter of the nozzle was 0.052 inches, the
angle of bevel surface 117 was fifteen degrees with respect to the
downstream surface of the nozzle, and the gap length 53 was 0.150
inches. When tested on flow bench calibration equipment, the fuel
channel was capable of flowing 440 cubic centimeters of fluid per
minute. As indicated by the line 126 the amount of fluid dispersed
from the channel increased with increasing air flow in the air
induction passage. It was substantially linear with air flow from
appproximately 55 cubic feet per minute of air to approximately 165
cubic feet per minute of air. In general, an increase in the length
of gap portion 53 tends to increase the slope of the linear portion
of characteristic line 126.
The line 127 of FIG. 7b illustrates flow characteristics of an
example embodiment of high range fuel channel 48. In the example
embodiment, the inner diameter of nozzle 98 was 0.052 inches, the
angle of bevel surface 121 was 45.degree. with respect to the
downstream surface of the nozzle, and the length of gap zone 52 was
0.060 inches. The fuel channel was capable of flowing 440 cubic
centimeters of fluid per minute. As indicated by the line 127, the
amount of fuel dispersed from the channel increased with increases
in the flow rate of air in the air induction passage, the rate of
increase being more pronounced at high air flows. In general, an
increase in the length of gap 52 tends to result in increased rate
of fuel delivery at higher air flow rates.
FIG. 8 illustrates an air fuel ratio obtainable by use of the above
described example embodiments of fuel channels 48, 49 and 51. The
line 128 is related to the line 124 of FIG. 5b and indicates the
rate of fuel delivery from idle channel 51. The line 129 is related
to line 126 of FIG. 6b and indicates the rate of fuel delivery from
both idle channel 51 and intermediate channel 49. The line 131 is
related to line 127 of FIG. 7b and indicates the total rate of fuel
delivery of the three channels 48, 49 and 51. It is to be noted
that the particular gap configuration employed in the examples
provides idle fuel requirements at low air flow rates, and then
provides a substantially constant air fuel ratio at higher air flow
rates as indicated by the linearity of line 131.
FIGS. 9, 9a and 9b are enlarged fragmentary views of an alternate
form of fuel channel 132 including a nozzle member 133 and a
receiver member 134. Nozzle member 133 and receiver 134 are adapted
for connection to fuel inlet and outlet passages. Nozzle member 133
includes a slot 136 in the upstream wall and a slot 137 in the
downstream wall. In this embodiment of fuel channel, air flowing in
an air induction passage impinges on a stream of fuel in nozzle
member 133 by means of the upstream slot 136. Impingement of the
air stream on the fuel stream forces fuel into the downstream slot
137 where portions of the fuel strike stripping surface 138 defined
by the end of slot 137 or stripping surface 139 defined by the end
of receiver member 134. Referring to FIG. 9c, the line 141
illustrates the fuel dispersion characteristic of the fuel channel
132 when the receiver 134 is in the full line position shown in
FIGS. 9 and 9a. When receiver 134 is adjusted to the dash line
position indicated as 142, the fuel dispersion characteristics is
as illustrated by line 143. In a similar manner, adjustment of
receiver 134 to the dash line position 144 provides a fuel
dispersion characteristic represented by line 146, and adjustment
to the position indicated 147 results in a fuel dispersion
characteristic as represented by line 148. It is to be noted that
channel 132 disperses increased amounts of fuel at higher air flow
rates similar to high range channel 48. The channel 132 provides an
advantage over the channel 48 in that the end of nozzle 133 is
telescopically received in receiver 134 which provides and
maintains flow alinement in the channel over a wide range of
adjusted positions. FIGS. 10, 10a and 10b are enlarged fragmentary
views illustrating the gap configuration of fuel channel 151
employed in the embodiment of charge forming apparatus shown in
FIGS. 11 and 12. Nozzle member 152 is connected to an inlet fuel
passage and has an end portion telescopically received in receiver
153 which is connected to a fuel outlet passage. A slot is formed
in the upstream surface of nozzle 152 defining a pair of side wall
edge portions 154, 156 and an end wall edge portion 157.
A stream of fuel in nozzle 152 undergoes a change of shape as a
result of the impingement of air thereon becoming wider in the gap
zone 159. The reformed stream of fuel extends laterally over the
sidewall edge portions 154, 156 such that portions of the stream
strike stripping surface 157 formed by the end of the slot or the
stripping surface 158 formed by the end of receiver 153. The
lateral margins of the reformed fuel stream are dispersed into the
air stream.
Referring to FIG. 10c, the line 161 graphically illustrates typical
fuel dispersion characteristics of channel 151 when the receiver
153 is in the full line position providing a maximum length of gap
159. Line 162 represents the fuel dispersion characteristics when
the gap length has been decreased by movement of the receiver to
the dash line position indicated as 163. Line 164 represents fuel
dispersion characteristics of channel 151 when the gap length has
been decreased approximately 50 percent as indicated by the dash
line position 166 of receiver 153. Similarly line 167 represents
the fuel delivery characteristics of channel 151 when approximately
three quarters of the gap length is obstructed as indicated by the
dash line position 168 for receiver 153.
The alternate embodiment of charge forming apparatus shown in FIGS.
11 and 12 is designated by the reference character 171 and includes
a body 172 similar to the body 21 of embodiment 20. Embodiment 171
employs a single fuel channel and an idle orifice. Body 172
includes an air induction passage extending therethrough having an
inlet or upstream portion 173, a mid portion 174 and an outlet or
downstream portion 176. The air induction passage may have a
constant diameter if desired, however, as shown in the drawings the
portions of the passage have different diameters selected to
provide substantially equal flow areas in view of the intrusion
into the induction channel of the choke, throttle, and fuel
channel. The upstream end of body 172 is provided with a boss 177
for mounting an air cleaner, while the downstream end of body 172
is provided with flange portions 178, 178 for securing the
apparatus to the induction manifold of an internal combustion
engine. A choke plate 179 and choke shaft 181 are mounted in
upstream portion 173 of the air induction passage in a conventional
manner. Throttle plate 182 and throttle shaft 183 are mounted in
downstream portion 176 of the air induction passage in a
conventional manner. An auxiliary air passage 184 has an outlet
port 187 in downstream portion 176 such that it by-passes mid
portion 174 of the air induction passage in which fuel channel 151
is located.
Nozzle 152 of fuel channel 151 is secured to a fitting 189 which
includes an aperture 191 and groove 192 permitting the passage of
fuel from an inlet passage to the nozzle. Fitting 189 is secured in
a bore 193 in body 172 similar to the manner in which fittings 62,
83 and 101 are securd in body 21. Seals 194, 194 surround fitting
189 on either side of groove 192 to prevent leakage between the
surface of the fitting and the wall of bore 193. A retainer ring
196 and set screw 197 secure the fitting and nozzle against
rotation and displacement with respect to the body.
Receiver 153 extends telescopically over nozzle 152, and as shown
in FIG. 11 is in a position similar to position 163 of FIG. 10
providing a gap configuration having fuel delivery characteristics
similar to line 162 of FIG. 10c. Receiver 153 is secured to a
fitting 198 which includes an aperture 199 and groove 201
permitting flow of fuel from the receiver to outlet passage 202.
Fitting 198 is received in bore 203 in body 172 having a seal 204
to prevent leakage between the wall of the bore and the surface of
the fitting. An end portion of fitting 198 is provided with a slot
206 and a threaded portion 207 by means of which the receiver can
be adjusted with respect to the nozzle to provide the desired
length of gap 159. A lock nut 208 on threaded portion 207 provides
means for securing fitting 198 and receiver 153 against
displacement from its adjusted position.
The downstream portion 176 of the air induction passage includes an
idle orifice 209 connected with a fuel passage 211 which is
connected to fuel outlet port 212. An idle adjusting screw 213 is
adjustable toward and from passage 211 by means of external slotted
portion 214 to provide a variable restriction for regulating the
fuel delivery capacity of idle orifice 209. While the idle orifice
209 is not essential to the operation of the embodiment 171, it is
beneficial for providing idle enrichment, particularly when its
location is below the closed position of the throttle plate
indicated by dash line 216 in FIG. 11. The idle orifice is exposed
to manifold vacuum when the throttle is closed, which results in
drawing fuel from the passage 211 even though there is minimal air
flow in the air induction passage.
The embodiment of FIGS. 1 through 4 is provided with a choke plate
26 in the inlet or upstream portion 22 of the air induction passage
and the embodiment of FIGS. 11 and 12 includes a similar choke
plate 179 is the upstream portion 173 of the air induction passage.
Each of the choke plates is mounted to permit rotation in the air
induction passage to form a variable restriction therein. The
pressure drop across the choke plate results in a lower ambient
pressure surrounding the fuel channel or channels in the
intermediate portion of the air induction passage. When the ambient
pressure surrounding the gap zone of a fuel channel is lowered, the
stream of fuel tends to expand more fully in the gap zone
permitting the dispersion of more fuel from the channel thus
providing a richer mixture. The use of choke plates in combination
with fuel channels is therefore beneficial during engine starting
and warm-up.
Referring now to FIGS. 13 through 17, an alternative embodiment of
charge forming apparatus is shown and described, characterized in
that it is more compact by reason of having a shorter air induction
passage. The shorter air induction passage is made possible by
elimination of the choke plate. Cold enrichment of the mixture is
provided by means of an enrichment channel.
The charge forming apparatus 220 includes a body 221 having an air
induction passage extending therethrough defined by an upstream
portion 222 and a downstream portion 223 which may be of the same
or different diameters depending upon whether it is desired to
compensate for differences in flow area resulting from the throttle
plate 224 and throttle shaft 226 extending across the passage.
One end of body 221 includes a boss portion 227 surrounding the
upstream end 222 of the air induction passage for mounting an air
cleaner thereon. The opposite end of body 221 includes flanges 228,
228 providing means for mounting the charge forming apparatus on an
inlet manifold of an internal combustion engine.
An auxiliary air passage is defined by inlet port 229, passage 231,
port 232, passage 233 and outlet port 234. During the wide open
throttle operation, the auxiliary air passage is ineffective
inasmuch as the ambient pressures at inlet port 229 and outlet port
234 are substantially equal. The auxiliary air passage is also
ineffective at closed throttle because the edge 236 of throttle
plate 224 is slightly downstream of outlet port 234 in the closed
position such that the inlet and outlet ports are exposed to
substantially the same pressure. As throttle plate 224 is turned
from closed toward wide open position, the edge 236 moves upstream
of outlet port 234. At part throttle, the pressure drop across the
throttle plate results in a somewhat lower pressure at the outlet
port 234 causing a portion of the air requirements to bypass the
fuel channels. Since a portion of the air requirement does not act
upon the fuel channels, a leaner mixture is provided for part
throttle operation.
Body 221 has a system of fuel passages including fuel inlet port
237, fuel inlet passages 238, 239, 241, fuel outlet passages 242,
243, 244, fuel outlet port 246, fuel channels 247, 248, 249, and
enrichment channel 251. In the illustrated embodiment, three fuel
channels are employed, however, the number, type and configuration
of fuel channels to be used may be varied to provide a desired fuel
delivery characteristic as described in connection with FIGS. 5
through 10c.
Nozzle fittings 252, 253 provide for flow of fuel from passage 238
to fuel channels 247, and 248 and are mounted in body 221 in a
manner similar to the mounting of fittings 83 and 101 of FIG. 3.
Nozzle fitting 254 is mounted in body 221 in a manner similar to
the mounting of fitting 62 and provides for flow of fuel from
passage 238 and 239 to fuel channel 249.
Receiver fittings 256, 257 and 258 are adjustably mounted in body
221 in a manner similar to the mounting of fittings 71, 92 and 109
and provide for flow of fuel from fuel channels 247, 248 and 249 to
fuel outlet passages and outlet port 246.
The arrangement of the fuel channels and passages is similar to the
arrangement described in connection with the embodiment of FIGS. 1
through 4 and it is believed that a more detailed description is
not required.
Referring now to FIGS. 15, 16, and 17, the enrichment channel 251
will be described in more detail. Enrichment channel 251 extends
across the downstream portion 223 of the air induction passage
downstream of the closed position of throttle plate 224. An inner
tubular nozzle member 261 is secured to a fitting 262 which is
nonrotatably secured in bore 263 of body 221. Fitting 262 includes
an aperture 264 and groove 266 which permit flow of fuel from
passages 238 and 241 to the tubular nozzle member 261. Seals 267
and 268 are located on opposite sides of groove 266 to prevent
leakage between fitting 262 and the wall of bore 263. The upstream
wall of nozzle member 261 is interrupted for a substantial portion
of its length defining side walls 271, 272 to provide an elongated
gap 269.
A rotatable receiver sleeve 273 extends across air induction
passage 223 surrounding nozzle member 261 being received in the
apertures 274, 276. Receiver sleeve 273 has a portion of the wall
interrupted to provide an elongated gap portion substantially
coextensive with the gap 269. Receiver sleeve 273 is secured to
fitting 277 which is rotatably mounted in bore 278 of body 221. An
aperture 279 and groove 281 permits flow of fuel from receiver 273
to fuel outlet passage 244. A seal 282 extends around fitting 277
to prevent leakage along the wall of bore 278. The seal and fitting
are secured against longitudinal displacement from bore 278 by a
retainer plate 283. An end portion 284 of fitting 277 extends
externally of body 221 and is secured to a lever 286 by means of
which the fitting and sleeve can be rotated.
Enrichment channel 251 is employed instead of a choke where an
enriched mixture is required as for cold starting and warm up of an
engine. For cold starting and warm up, the throttle plate 224 is
turned to its closed position where it lies upstream of enrichment
channel 251. Receiver sleeve 273 is rotated to the position shown
in FIG. 17 wherein the gap in the upstream portion of nozzle 261 is
exposed. Under these conditions the gap is exposed to
subatmospheric pressures from the engine manifold. A stream of fuel
in the gap zone 269 expands more fully in the presence of a
subatmospheric ambient pressure resulting in an enriched mixture.
As the engine progresses through warm up, the receiver sleeve 273
is rotated around nozzle 261 to progressively cover the gap zone
269. Rotation of sleeve 273 in the closing sense confines a greater
portion of the fuel stream in the channel such that the mixture
becomes less rich. When sleeve 273 is rotated to a fully closed
position (180.degree. from the position of FIG. 17), the fuel
stream in nozzle 261 is confined in the channel such that its
enrichment function is nullified.
It is to be recognized that the foregoing description relates to
exemplary embodiments of the invention which may be adapted and
modified as required for providing desired mixture
requirements.
* * * * *