U.S. patent number 3,866,585 [Application Number 05/081,706] was granted by the patent office on 1975-02-18 for high energy fuel atomization and a dual carburetion embodying same.
Invention is credited to Richard D. Kopa.
United States Patent |
3,866,585 |
Kopa |
February 18, 1975 |
HIGH ENERGY FUEL ATOMIZATION AND A DUAL CARBURETION EMBODYING
SAME
Abstract
A fuel atomizing carburetion system incorporating means for fuel
atomization and flash vaporization in a heated evaporation chamber,
separated from the main air induction system, and means for
transferring the fuel vapor into a cyclonic flow inductor in which
a mixing process with the cold inlet air occurs, for the purpose of
generating a well-homogenized combustible mixture of completely
vaporized fuel, inlet air, and recycled exhaust gas, with a minimal
temperature rise of the mixture, in order to avoid the consequent
increase of nitric oxide formation during the engine combustion
process. A fuel atomizing carburetion system incorporating a
pneumatic control system for the continuous control of the air-fuel
ratio, exhaust gas recycling rate, and of the heat transfer rate to
the atomized vaporizing fuel, in order to obtain an optimal
reduction of engine exhaust emission and optimal engine
performance.
Inventors: |
Kopa; Richard D. (Encino,
CA) |
Family
ID: |
22165863 |
Appl.
No.: |
05/081,706 |
Filed: |
October 19, 1970 |
Current U.S.
Class: |
123/442; 123/548;
123/568.15 |
Current CPC
Class: |
F02M
31/047 (20130101); F02M 29/06 (20130101); F02M
26/36 (20160201); F02M 7/12 (20130101); F02M
19/03 (20130101); F02M 1/00 (20130101); Y02T
10/12 (20130101) |
Current International
Class: |
F02M
31/04 (20060101); F02M 7/00 (20060101); F02M
29/06 (20060101); F02M 19/03 (20060101); F02M
7/12 (20060101); F02M 25/07 (20060101); F02M
19/00 (20060101); F02M 29/00 (20060101); F02M
31/02 (20060101); F02M 1/00 (20060101); F02m
025/06 () |
Field of
Search: |
;123/119A,127 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Burns; Wendell E.
Claims
1. A liquid fuel and air carburetion process for an internal
combustion engine, that comprises:
providing one confined minor and one confined major stream of
intake air spinning cyclonically about a longitudinal spin
axis;
jetting into the minor air stream, in the downstream direction
thereof, an expanding major spray of liquid fuel that is atomized
by impingement by a stream of pressurized gas directed downstream
along said axis so as to mix the atomized and vaporizing liquid
fuel with said minor air stream, and the recycled hot exhaust gas,
injected in close proximity of said expanding major spray of liquid
fuel;
guiding the resulting confined turbulent mixture stream through a
heated space where a complete vaporization of liquid fuel takes
place and transferring said mixture stream into another unheated
space where a mixing with a confined cyclonically spinning major
stream of unheated intake air takes place;
guiding the final confined cyclonically spinning mixture stream to
turn to one side and into a circular flow path closing on itself,
such that the mixture stream continues its cyclonic spin, and spins
additionally around said circular flow path;
drawing off vaporized and homogenized mixture from the mixture
stream
2. The subject matter of claim 1, including jetting, into the
spinning major stream of inlet air, in the downstream direction
thereof, an expanding minor spray of liquid fuel that is atomized
by impingement of
3. A carburetor for supplying a combustible, well-homogenized
air-fuel mixture to the intake manifold of an internal combustion
engine, comprising:
a housing having a dual induction air passage and a dual fuel
discharge means, a means for introducing recycled exhaust gas, a
means for evaporation of the atomized fuel and a means for cyclonic
homogeneous mixing of all gaseous components,
said dual induction air passage separating the flow of inlet air
into a minor portion of air entering into a fuel evaporation
chamber, and into a major portion of air entering directly into a
cyclonic flow inductor, said dual fuel discharge means delivering
the major portion of atomized fuel into said fuel evaporation
chamber and the said minor portion of atomized fuel into the inelt
of said cyclonic flow inductor, in order to further reduce the
temperature of said major portion of inlet air, said means for
introducing recycled exhaust gas into the said fuel evaporation
chamber, in order to increase the rate of vaporization of the
atomized fuel due to heat transfer from the hot recycled exhaust
gas to the atomized fuel droplets,
and means for transferring of the mixture of vaporized fuel,
recycled exhaust gas and of the minor portion of inlet air into the
said cyclonic flow inductor where the homogeneous intermixing of
all said gaseous components with said major portion of unheated
inlet air takes place, in order to produce well-homogenized
combustible mixture, substantially below the equilibrium
temperature of said vaporized fuel, persisting in "super
4. The subject matter of claim 3, including auxiliary throttle
valves mounted in the outlet of said cyclonic flow inductor in
exactly the same location in respect to the engine inlet manifold
as the throttle valves of a conventional carburetor,
said auxiliary throttle valves synchronized by means of a "lost
motion linkage" with the primary and secondary throttle valves,
located in said dual induction air passage of the carburetor, in
such a way as to allow a small advance in the opening as well as in
the closing motion of the auxiliary throttle valves, in order to
obtain smooth idling of the engine and to decrease the emission of
unburned hydrocarbons during the
5. The subject matter of claim 3, including step-baffles arranged
in the vicinity above the heated sloping of said cyclonic flow
inductor in such a way as to prevent the heat transfer from said
heated wall to the combustible mixture, however, to permit any
liquid fuel which remained unvaporized to flow between the
step-baffles onto a heated wall and have
6. The subject matter of claim 3, including means for aerodynamical
draw-off of the gaseous mixture from said evaporation chamber into
said
7. The subject matter of claim 3, including means for additional
control of air flow through said dual induction air passage at cold
as well as hot engine operation during sudden opening and the wide
open position of said primary throttle valve.
Description
This invention relates generally to carburetors for internal
combustion engines and has more particular reference to
improvements in fuel atomizing carburetors. It has become apparent
from research in automotive air pollution that the three major
contaminants present in the exhaust gas emissions from gasoline
powered motor vehicle engines are carbon monoxide, hydrocarbons,
and nitrogen oxides. The inventions disclosed in my previous U.S.
Pat. Nos.--3,376,027 entitled Fuel Atomizing Carburetors, 3,336,017
entitled Compound Cyclonic Flow Inductor and Improved Carburetor
Embodying Same, 3,395,899 entitled Carburetor, and 3,384,059
entitled Carburetion System with Improved Fuel-Air Ratio Control
System--propose certain new and unique carburetion techniques which
are effective to reduce substantially the air contaminants,
particularly the three major contaminants just listed, which are
present in automotive gas emissions. More specifically, my prior
inventions, just referred to, relate to improved fuel atomizing
carburetors which utilize, among others, two effective techniques
for reducing exhaust gas contaminants. One of these techniques is
that of introducing exhaust gas, or other inert fluid, either
liquid or gaseous, into the iar-fuel mixture entering the engine to
reduce the peak combusion temperature of the mixture, and thereby,
the formation of nitrogen oxides. It should be noted that when
emitted into the atmosphere, the nitric oxide converts to nitrogen
dioxide--a toxic fgas--which upon exposure to sunlight acts as a
photoreceptor and, in the presence of unburned hydrocarbons,
triggers the photochemical reactions in contaminated atmosphere
leading to the manifestations commonly called "smog." The second
technique is that of effecting substantially total vaporization of
the fuel and substantially complete homogeneous intermixing of the
fuel vapor, induction air, and recycled exhaust gas in such manner
as to permit engine operation at an air-fuel ratio with a
substantial excess of air and thereby achieve more complete
combustion of the hydrocarbons in the fuel and reduce the formation
of carbon monoxide. To preserve at the same time a good engine
operating characteristic, it is necessary to ensure that every
cylinder of a multicylinder engine is supplied with a
well-homogenized combustible mixture of the same air-fuel ratio
from cylinder to cylinder and from cycle to cycle. The inventions
disclosed in my previous patents accomplish this task by the
following means: (1) fuel atomization, (2) instant vaporization of
fuel droplets, (3) recycling of exhaust gas for the control of
nitric oxide, and (4) homogenation of the combustible mixture by
cyclonic mixing of the vaporized fuel, inlet air, and the recycled
exhaust gas. In particular, my U.S. Pat. No. 3,336,017, Compound
Cyclonic Flow Inductor and Improved Carburetor Embodying Same,
describes a carburetion process for complete vaporization of
atomized fuel in air which is subjected to compound cyclonic motion
in a specially designed flow inductor-mixing chamber. The heat
necessary for the vaporization of fuel is supplied by means of a
heated fluid jacket enveloping the outer periphery of the mixing
chamber.
Evidently, the heating of the inlet air as required for complete
vaporization of the supplied fuel will result in a rise in the
temperature of the combustible mixture. It is well known, however,
that an increase in air-fuel mixture temperature will result in
higher combustion temperature and, consequently, in higher emission
of nitric oxide. The general objective of the present invention is
to eliminate this particular deficiency and further to improve
several other aspects of the inventions disclosed in my previous
patents.
Briefly, the objects of the invention are attained by providing a
means for separating the flow of inlet air into a minor portion
passing through an evaporation chamber and the major portion of air
passing through the cyclonic flow inductor. In this manner, only
that amount of the total air flow is heated--about 10%--which is
necessary for the vaporization of fuel in the evaporation chamber,
and 90% remains cold, to be later homogenized in the cyclonic flow
inductor, along with the recycled exhaust gas, fuel vapor, and the
aforementioned small amount of warm air. Thus a reduction in the
temperature of the combustible mixture and a concomitant reduction
in the formation of nitric oxides is effected. It should be noted
that the relationship between the formation ot the nitrogen oxides
and the combustion temperature is an exponential one. Accordingly,
even a small decrease in the peak combustion temperature results in
a substantial reduction in the formation of nitrogen oxides.
Of course, the system must be effective under twofold conditions,
to wit, during steady state engine operation, e.g., cruising and
idling, and during transient engine operation, e.g., acceleration
and deceleration. To this end, the present carburetor has been
provided with a control system which maintains the correct air-fuel
ratio for optimum engine performance and optimum emission control
throughout the entire operating range of the engine.
With these and other objects in view, the invention consists in the
construction, arrangement, and combination of the various parts of
the invention, whereby the objects contemplated are attained, as
hereinafter set forth, pointed out in the appended claims, and
illustrated in the accompanying drawings.
The invention will be now described in greater detail by reference
to the attached drawings, wherein:
FIG. 1 illustrates the principle of High Energy Fuel Atomization
according to this invention;
FIG. 2 is a vertical section through the carburetor, the cyclonic
mixing chamber, and the engine inlet manifold; taken on 2--2
FIG. 3 is a horizontal section through the carburetor and the
mixing chamber;
FIG. 4 is a horizontal section through the carburetor main
body;
FIG. 5 is a vertical section through the carburetor primary
barrel;
FIG. 6 is a vertical section through the carburetor secondary
barrel; and
FIG. 7 is a section taken on line 7--7 in FIG. 4.
The principle of high energy fuel atomization and flash
vaporization is schematically presented in FIG. 1. Air enters the
inlet 1 of a compound cyclonic flow inductor 2, passes through the
main throttle valve 3 and helical veins 4 located circumferentially
around the venturi 5. Fuel enters through a duct 6 the pneumatic
atomizing nozzle 7 and is atomized by means of preheated atomizing
air supplied through a duct 8 and injected into evaporation chamber
9, which is enveloped by a fluid heating jacket 10. A small amount
of secondary air, less the 10% of the total air-inlet quantity,
passes through the evaporation chamber 9 in order to increase the
rate of flow-through and promote the turbulence and fuel
evaporation process in the evaporation chamber 9. The rate of flow
of the secondary air is controlled by a throttle valve 11 which is
synchronized with the main throttle valve 3 by means of linkage 12.
Hot recycled exhaust gas, primarily for the control of nitric
oxide, is injected in close vicinity to the atomizing nozzle 7
through a duct 13. The heat of the recycled exhaust gas contributes
to instant vaporization of the atomized fuel droplets. The mixture
of vaporized fuel, secondary air, and recycled exhaust gas is
aspirated through the venturi 5 and is discharged into the primary
air stream which is spinning cyclonically about a longitudinal axis
of the inlet section 14 of the compound cyclonic flow inductor 1.
The resulting confined cyclonically spinning mixture stream is
guided to turn to one side and into a circular flow path closing on
itself, such that the mixture stream continues its cyclonic spin,
and spins additionally around the circular flow path, effecting an
intensive turbulent intermixing of all components. The homogenized
combustible mixture is drawn off through a large number of holes in
a perforated baffle 15 into the inlet barrels 16 of the engine
inlet manifold. The cyclonic flow inductor 2 has no heating jacket,
and consequently no heat from the heating fluid is transferred, to
the primary inlet air entering through the main throttle valve 3.
As compared to the carburetion process described in my previous
U.S. Pat No. 3,336,017, where the entire combustible mixture is
heated to the fuel vaporization temperature, the process of this
invention represents a substantial reduction of necessary heat
input for the total vaporization of atomized fuel and also a
substantial reduction in the resulting temperature of the
combustible mixture. The magnitude of this reduction becomes
evident when one considers that a mass of fifteen, or more, pounds
of air is carbureted with the mass of every one pound of fuel.
Since in this process the resulting temperature of the combustible
mixture is below the equilibrium temperature of the fuel vapor, the
fuel vapor after mixing with the primary cool air becomes "super
colled." However, because of the high flow velocity of the
combustible mixture in the entire carburetion and engine inlet
system, there is not sufficient time for condensation of the fuel
vapor back to liquid state. Therefore, the fuel persists in a
gaseous state until it arrives to the individual cylinders of the
engine.
A physical embodiment of the above principle is presented in FIG. 2
and FIG. 3. For the reason of compactness, the evaporation chamber
9 is "wrapped around" the cyclonic flow inductor 2. In this way,
the primary air throttle valve 3 and the secondary air throttle
valve 11 can be mounted on a common shaft 17 in a single carburetor
body 18 containing side by side a primary air inlet barrel 19 and
secondary barrel 20. The mixing venturi 5 is replaced by a series
of blades 21 located circumferentially around the cyclonic flow
inductor 2 in such a fashion that they replace a major part of the
outer wall of the flow inductor 2 and permit the flow of the fuel
vapor, secondary air, and recycled exhaust gas mixture from the
evaporation chamber 9 into the cyclonic flow inductor 2 but
prevent, because of aerodynamic forces, the flow in the reverse
direction, namely, from the cyclonic flow inductor 2 into the
evaporation chamber 9. The evaporation chamber 9 is on its outer
circumference and bottom part enveloped by a heating jacket 10,
which extends also over the bottom part of the cyclonic flow
inductor 2. The heat transfer from the jacket 10 to the combustible
mixture in the cyclonic flow inductor 2 is barred by means of a set
of circular concentric step-baffles 22 arranged in the vicinity
above the sloping bottom wall 23 of the flow inductor 2. The
step-baffles 22 permit, however, any liquid fuel which was injected
directly into the cyclonic flow inductor 2 and remained unvaporized
to flow through the circular clearances 24 between the step-baffles
22 onto the heated sloping wall 23 and have another chance to be
vaporized.
At light and medium loads of engine operation, the major portion of
the supplied fuel (about 90percent) is atomized by means of the
pneumatic atomizing nozzle 7 located in the secondary barrel 20 and
injected into the evaporation chamber 9. The minor portion of the
supplied fuel, about 10%, is atomized by means of the pneumatic
atomizing nozzle 25 located in the primary barrel 19 and injected
directly into the cyclonic flow inductor 2. At the same time, the
inlet air flow distribution ratio is the reverse. That is, in the
same way as indicated in FIG. 1, a major portion of inlet air
(about 90%) flows through the primary barrel 19, and the minor
portion of inlet air flows through the secondary barrel 20. The
minor portion of fuel atomized directly into the cyclonic flow
inductor 2 vaporized partially or completely by means of heat which
it extracts from the surrounding (major) inlet air, which in turn
is efficiently cooled below its original ambient temperature. On
the other hand, the major portion of fuel atomized into the
evaporation chamber 9 is instantly vaporized by the efficient heat
transfer from the recycled hot exhaust gas, injected through
openings 26 circumferentially distributed at the entrance of the
evaporation chamber 9, and from the super-heated minor portion--or
secondary--inlet air and the fuel vapor. The optimal super-heating
of the combustible mixture inside the evaporation chamber can be
attained by the design for optimal ratio of the mixture mass flow
rate through the jacket-heated evaporation chamber 9 to the flow
rate of the heating fluid through the heating jacket 10. The
heating jacket 10 has inlet and exhaust flanges 27, which are
connected to short bypass ducts 28. The bypass ducts 28 are fitted
into the openings drilled in the cross-over heating passage 29 of
the engine inlet manifold 30. The ducts 28 are sealed against a
leakage by means of copper sleeves 31 clamped to the inlet manifold
30. The inserted portions of the ducts 28 are shaped in such a way
as to block off the flow of exhaust gases through the crossover
heating passage 29 and divert the flow through the heating jacket
10. By these means, first, an undue heating of the already
homogenized combustble mixture in the engine inlet manifold 30 is
prevented, and, secondly, because of the short length of the bypass
ducts 28, the radiation heat losses of the heating fluid are
minimized. Between one flange 27 and duct 28 is mounted a throttle
valve 32. The opening position of valve 32 is set by a pneumatic
actuator 33 which responds to the controlled vacuum from controller
34. The controller 34 responds to several pertinent input signals,
such as the engine manifold vacuum 35, engine temperature 36,
exhaust gas emission level 37, and so forth, and its function is to
control certain carburetor operational parameters in order to
maintain the lowest possible engine exhaust emissions. The
operation of the controller 34 and the associate systems will be
discussed in greater detail. below.
During engine acceleration and or high engine load operation, the
ratio of air flow through secondary barrel 20 to air flow through
primary barrel 19 is increased in order to intensify the mixing
process in chamber 9 as well as in the cyclonic flow inductor 2.
This is accomplished by a special shape of the throttle valve 11 as
shown in FIG. 6. At the same time, the ratio of fuel injection rate
from the atomizing nozzle 25 to the fuel injection rate from the
atomizing nozzle 7 is increased in order to obtain good
acceleration response and maximum power at full load operation.
This is accomplished by the mechanism described in FIG. 4 through
FIG. 7. The rate of exhaust gas recycling is adjusted by a throttle
valve 38, which is positioned by a pneumatic actuator 39 responsive
to the regulated vacuum from the controller 34. The controller 34
optimizes the exhaust recycling rate to achieve the lowest nitric
oxide emission and the best engine performance trade-off. During
engine deceleration, the over-all air-fuel ratio is adjusted to
obtain the lowest emission of unburned hydrocarbons by means of the
controller 34 and the regulators 40 and 41, as described in detail
in FIG. 6 and FIG. 7.
The engine cylinder inlet and exhaust valve timing, the inlet
manifold configuration and volume, and the conventional carburetor
have to be "tuned together" in order to obtain a reliable idling of
the engine at low RPM. If the conventional carburetor is replaced
by a fuel atomizing carburetor with a cyclonic mixing chamber of
considerable volume, the original "gas-dynamical tune-up" of the
induction system is likely to be upset, and the engine will not
satisfactorily idle at factory specified RPM. To eliminate this
problem, the fuel atomizing carburetor described herein is provided
with auxiliary throttle valves 42 attached to the shaft 43 in
exactly the same location in respect to the inlet manifold 30 as
were the throttle valves of the original conventional carburetor.
The motion of shaft 43 of the auxiliary valves 42 is synchronized
by means of linkage with the motion of the shaft 17 of the primary
throttle valve 3 and the secondary throttle valve 11. The linkage
is designed so as to allow a small advance in the opening motion to
the auxiliary valves 42 in order to transmit a full manifold vacuum
to the space inside the flow inductor and evaporation chamber
assembly. To prevent eventual damage of the carburetor from
accidental backfire in the induction system, the cyclonic mixing
chamber is provided with a spring-loaded lid 43 for instantaneous
release of the explosion pressure.
The fuel atomizing nozzles 7 and 25 are described in FIG. 4 through
FIG. 7. Both nozzles are of the external mixing type; this means
that the atomizing air which enters the carburetor body 18 through
a channel 44, and is distributed by means of the branch 45 to
nozzle 7 and branch 46 to nozzle 25, expands at high velocity
through clearances 47 and 48, respectively, and atomizes by a
mechanism of molecular collision the fuel emerging from nozzle
mouths 49 and 50, respectively. The rate of fuel flow is controlled
by means of the needle 51 positioned in the metering orifice 52 of
the atomizing nozzle assembly 7 and by the needle 53 and orifice 54
for the nozzle 25, FIG. 7, as well as by the suction pressure
maintained in the space 55 on the discharge side of the orifice 52
and in the space 56 on the discharge side of the orifice 54. The
suction pressure is regulated by means of the pressure regulator 40
or the regulator 41, selectively, in the following way: If the
teflon sliding valve 57 is in closed position in respect to channel
58, then the atmospheric air can enter only the bottom side of the
regulating diaphragm 59 of the regulator 40 by means of the channel
60. The suction pressure existing in the space 61 is communicated
to the upper side of the diaphragm 62 by means of the feedback
channel 63. The pressure difference between the atmospheric
pressure on the bottom side of 59 and the suction pressure at the
upper side of 62 exerted over the area of the diaphragms 59 and 62
balances the spring 64, which forces the diaphragm 59 against the
seat 65, in such a way that a nearly constant suction pressure in
the space 52 and the space 56 is maintained independently of the
manifold vacuum fluctuation in the evaporation chamber 9 and the
cyclonic flow inductor 2. The tension of the spring 64 in the
regulator 40 is adjusted by means of screw 66, so as to maintain a
certain suction pressure level corresponding to a desired air-fuel
ratio setting of the carburetor at cold start and cold engine
operation. As the engine warms up, a conventional thermostat
rotates the shaft 67 to pull the teflon valve in the open position
so that the atmospheric air is transferred by means of channel 58
to the regulator 41. The tension of the spring 68 is adjusted by
means of screw 69 to a substantially lesser value, and consequently
the suction pressure in the spaces 52 and 56 will be maintained at
a level corresponding to a leaner air-fuel ratio setting as
required during hot engine operation. The system described above
maintains a constant air-fuel ratio over a wide range of the
manifold vacuum, with a progressive enrichment of the air-fuel
ratio as the manifold vacuum approaches lowest values at high load
engine operation. It is essential, however, that the air-flow as
regulated by the pressure regulator 40 or 41 is directed against
the discharge side of the metering orifices 52 and 54 in such a way
that a stagnation pressure corresponding to the regulated pressure
level exists at the metering orifices. The geometry of the spaces
56 and 52 is apparent in FIG. 6 and FIG. 7.
Since the atomizing nozzle 25 is remote from the metering orifice
54, the mixture of fuel and air emerging from the apace 56 is
transferred by means of channel 70, which merges tangentially into
the swirl cavity 71 located in the proximity of the atomizing
nozzle discharge mouth 50. By the resulting swirling motion in
cavity 71, the air bubbles are separated from the aspirated fuel,
as is essential for even discharge and smooth atomization of fuel
by the atomizing nozzle 25. At full throttle operation, the
manifold vacuum reduces to nearly atmospheric pressure, and
consequently both regulators 40 and 41 will maintain the same
suction pressure in spaces 56 and 52, resulting in the same
air-fuel ratio. To compensate for this deficiency, an air valve 72
is provided in the primary barrel 19. The air valve 72 is mounted
on shaft 73 with attached torsional spring 74. The end of the
spring 74 engages with a pin 75 located on a slide 76, which is
positioned by arm 77 attached to the thermostat shaft 67. At cold
engine operation, the thermostat shaft 67 is rotated clockwise,
closing the teflon valve 57 and moving the slide 76 to a position
in which the pin 75 engages with the spring 74. The air valve 72
which is opened in proportion to air flow through the primary
barrel 19 must rotate against the tension of spring 74, and
therefore exerts a choking effect on the air flow through the
barrel 19. At hot engine operation, the thermostat shaft 67 is
rotated counterclockwise, and the pin 75 is disengaged from the
spring 74 so that the air valve 72 can rotate freely. A hydraulic
dashpot can be attached to the shaft 73 so that at a sudden opening
of the throttle valve 3 the air valve 72 opens progressively, thus
effecting a temporary enrichment of the air-fuel mixture during
acceleration. An additional enrichment of the air-fuel mixture
during acceleration and high load operation is provided by means of
an auxiliary power nozzle 78, which is supplied with fuel from a
conventional diaphragm fuel chamber 79. The diaphragm 80 becomes
inoperative, however, at high inlet manifold vacuum, corresponding
to lighter engine load. This is accomplished by immobilizing the
diaphragm 80 on the seat 81 by means of suction in the conduit 82.
The suction in the conduit 82 results when the air bleeder flow
through the orifice 83 is unbalanced by the suction flow through
the orifice 84 at elevated manifold vacuum.
As mentioned above, the emission of unburned hydrocarbons during
deceleration can be substantially reduced if the air-fuel ratio of
the combustible mixture is temporarily increased. Such transient
increase of air-fuel ratio can be conveniently accomplished by
means of a controller with a built-in variable-lead function, as
shown in FIG. 7. A controller 85, which represents a simplified
version of a more complex controller system 34 as indicated in FIG.
2, is connected to the inlet manifold by means of a threaded port
86. The sudden rise in manifold vacuum during engine deceleration
is transmitted to the cavity 87 below the diaphragm 88, and through
a restricting orifice 89 to the cavity 90 above the diaphragm 88.
Because the cavity 90 is larger than cavity 87 and communicates
with the manifold vacuum through the restriction 89, any change in
pressure signal at 86 will manifest itself more slowly in cavity 90
than in cavity 87. Consequently, a sudden increase of manifold
vacuum will cause the diaphragm to move downward and to open the
valve 91. Therefore, the manifold vacuum will be transmitted to the
channel 91, and by means of conduit 93 to the space between the
diaphragms 59 and 62 of the pressure regulators 41 and 40. The
diameter and corresponding surface of the diaphragm 59 is larger
than that of diaphragm 62. Therefore, the supplied vacuum will
result in a differential pressure upward against the tension of the
springs 64 and 68, with the effect of a leaner adjustment of the
air-fuel ratio. As soon as the pressure in caivity 90 equalizes
with the pressure in cavity 87, the spring 94 closes the valve 91,
and the vacuum in the conduit 93 dissipates through the bleeder
orifice 95 so that the steady state condition is reestablished. The
duration and timing function of this transient leaning can be
modified by the choice of the volume ratio of cavities 87 and 90,
and by the choice of the proper size of orifices 89 and 95.
Superimposed on this method can be a steady state modification of
the air-fuel ratio as a function of the manifold vacuum by means of
a bleeder orifice 96 continuously communicating the manifold vacuum
signal to the channel 92.
It is evident that similar controller-regulator systems can be
employed to control the exhaust recycling valve 38 or the heat
input control valve 32 of the jacket 10. All such components can be
combined in one integral controller unit 34, as suggested in FIG. 2
and FIG. 3, and developed to the desired degree of sophistication
in order to satisfy best the trade-off of requirements for low
emmission, engine performance, and simplicity of the whole
system.
The positioning motion of the needle valves 51 and 53 is
synchronized with the opening motion of the throttle valves 3 and
11, so as to maintain a nearly constant opening ratio of the total
air flow area to the total fuel flow area throughout the entire
operating range. The motion from the shaft 17, FIG. 4 through FIG.
7, is transmitted by means of the attached arm 97 and a roller 98
to a pivoted actuating arm 99. The arm 99 rests against an
actuating pin 100, which is supported by a compression spring 101.
At the lower extension of the pin 100 is attached needlle valve 53,
and by means of brace 102 is attached needle valve 51. Needle valve
53 penetrates through the fuel metering orifice 54 into a fuel
collector 103, and needle valve 51 penetrates through fuel metering
orifice 52 into fuel collector 104.
For a reliable start of the cold engine, a large amount of fuel has
to be supplied during the cranking operation. This is accomplished
in the present invention in the following way: During cold start,
the teflon slide valve 57, FIG. 6, closes off the channel 58. A
similar valve actuated from the thermostat shaft 67 located beside
the valve 57 closes off channel 105, FIG. 7. Channel 105
communicates with the well 106 and the discharge channel 107, FIG.
4. The well 106 is vented by a bleeder vent 1076. During cranking
of the engine, the spring 108 holds the diaphragm 109 away from the
seat 110, and fuel is aspirated from the fuel float chamber 111
into the discharge channel 107, and through the discharge port 112
into the conduit 113. Conduit 113, FIG. 4, delivers the fuel
directly to inlet barrels 16, FIG. 3, above the engine inlet
manifold 30. Once the engine starts, the manifold vacuum is
transmitted through the conduit 113 into the cavity 114 above the
diaphragm 109, which is pulled against the seat 110 and shuts off
further delivery of the starting fuel. As soon as the engine warms
up, the thermostat shaft 67 rotates counterclockwise and a teflon
slide valve opens the channel 105. If the engine is being
restarted, no starting fuel is aspirated, since the suction in the
discharge channel 107 is abosrbed by the air flow through the open
channel 105.
While the invention has herein been shown and described in what is
conceived to be its most practical and preferred embodiments, it is
recognized that departures may be made therefrom within the scope
of the invention, which is not to be limited to the details
disclosed herein, but is to be accorded the full scope of the
claims so as to embrace any and all equivalent devices.
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