Note: Descriptions are shown in the official language in which they were submitted.
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This inVention relates to an attraction ~ethod for lean
air-fuel mixture to be supplied to the combustion chamber in a
- cylinder and an attraction electrode plug for use in the attraction
method.
The prior art and the present invention will now be
described with reference to the accompanying drawings, in which:
Fig. 1 is an explanatory view of a prior art lean air-
fuel mixture attraction method employing corona discharge electrode
plugs;
Fig. 2 is a view showing the relationship between the
strokes in an engine utilizing the prior art method shown in Fig.
1 and the voltage within the combustion chamber;
Fig. 3 is a view showing one embodiment of the lean air-
fuel mixture attraction method by the present invention;
Fig. 4 is a view showing the relationship between the
- engine strokes in an engine utilizing the present invention and
the voltage within the combustion chamber;
Fig. 5 is a performance comparison diagram of the prior
art method and the method of the present invention;
Fig. 6 is an elevational view in partial section of an
embodiment of the attraction electrode plug of the present inven-
tion;
Figs. 7, 8 and 9 are elevational views of other embodi-
ments of the attraction electrode plugs of the present invention in
partial section;
Fig. 10 is a cross-sectional view taken along the line
10-10 of Fig. 9;
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Fig. ll is an elevational view of another embodiment
of the attraction electrode of the present invention in partial
section;
Fig. 12 is a view showing another embodiment of the lean
air-fuel mixture attraction method of the present invention; and
Fig. 13, appearing on the same drawing sheet as Fig. l,
is a view of still another embodiment of the invention.
One prior art method for collecting fuel particles in a
lean air-fuel mixture to be supplied to the combustion chamber in
a cylinder and igniting the lean air-fuel mixture is designed to
cause corona discharge by means of a corona discharge electrode 90
to collectthe fuel particles and ignites the lean air-fuel mixture
as shown in Fig. l.
However, in the prior art method, since a negative pres-
sure generates in the cylinder on the suction stroke of the engine,
the corona discharge electrode 90 tends to cause glow discharge
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and the high voltage applied to the corona discharge electrode 90
drops suddenly as shown in Fig. 2 and is not capable of maintaining
the fuel particles at and about the spark gap 22 of the ignition
plug 20 resulting sometimes in failure of ignition.
The present invention is designed to eliminate the dis-
advantages inherent in the prior art method as mentioned hereinabove
and provide an attraction method for lean air-fuel mixture in which
the fuel particles in the lean air-fuel mixture are always attract-
ed to and about the spark gap of the ignition plug and maintained
there until the time of ignition to the degree that the combustion
of the fuel can be positively effected, an attraction electrode
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capable of attracting the fuel particles in the lean air-fuel
` mixture by electrostatic induction and an attraction method for
lean air-fuel mixture disposed in such a manner that the distribu-
tion of the fuel particles which flow into manifolds in communi-
cation with cylinders can be made evenly to the respective cylinders.
According to a broad aspect of the present invention,
there is provided an apparatus for igniting a lean air-fuel mixture,
said apparatus comprising means for defining a combustion chamber,
said means for defining a combustion chamber including a cylinder
head, a spark plug mounted in said cylinder head, said spark plug
including a straight longitudinally extending main electrode ex-
tending into the combustion chamber and exposed to the atmosphere
in the combustion chamber and a side electrode disposed adjacent
to said main electrode and electrically insulated from said main
electrode, an attraction plug mounted in said cylinder head at
a location offset to one side of and adjacent to said spark plug,
said attraction plug including a straight longitudinally extending
central electrode, a metal body connected with said cylinder head,
and insulator means at least partially encasing said central
electrode for electrically insulating said central electrode from
said metal body and said cylinder head and for isolating the por-
tion of said central electrode disposed in the combustion chamber
from the atmosphere in the combustion chamber, said central elec-
trode of said attraction plug having a longitudinal central axis
extending transversely to the longitudinal central axis of said
main electrode of said spark plug and an end portion which is
disposed adjacent to said main electrode and is encased by sa.id
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insulator means, means for applying an electrical potential to
said central electrode of said attraction plug to establish an
electrostatic field in the combustion chamber to attract fuel
particles to the vicinity of the end portion of said central elec-
trode of said attraction plug and to a gap between said main and
side electrodes of said spark plug without establishing a corona
discharge in the combustion chamber, and means for applying an
electrical potential to said main electrode of said spark plug to
establish a spark between said main and side electrodes to ignite
fuel particles attracted to the vicinity of said spark plug by the
electrostatic field from said attraction plug.
The invention will now be described in greater detail
with particular reference to Figs. 3-13 of the drawings.
Fig. 3 shows one embodiment of the lean air-fuel mixture
attraction method according to the present invention and as shown
in this figure, à combustion chamber 11 defined in the cylinder
head 10 is provided with an ignition plug 20 and an attraction
electrode plug 30 with the leading end 35 of the center electrode
32 of the attraction electrode plug 30 positioned adjacent to the
spark gap 22 of the ignition plug 20. The leading end 35 of the
center electrode 32 has an electrostatic induction means 36
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surrounding the leading end.
The ignition plug 20 is electrically conn~cted to an ignition
circuit 23 throu~h a terminal 21 provided at the end of the plug
remote from the spark gap 22 and the ignition circuit is
conventional and includes a battery 24, a prim.ary coil 25, a
secondary coil 26, a contact 27 and a distributor 28. The
ignition circuit 23 is regulated to work for ignition when fuel
particles 100 are attracted and accumulated at and about the
spark gap 23 to form an ignitable lean air-fuel mixture layer
101 there.
The attraction electrode plug 30 comprises a metal main
body 31 (Fig. 6) through which the center electrode 32 extends
and one end or the outer end 33 of the center electrode 32 is
electrically connected to a hlgh voltage application circuit 37
and the other or inner end 35 of the center electrode has the
electrostatic induction means 36 thereon. An intermediate
portion of the center electrode 32 between the opposite ends is
surrounded and supported by an electrical insulator 34. In one
embodiment, the electrostatic induction means 36 comprises an
electrical insulator surrounding the other end 35 of the center
electrode 32. The high voltage application circuit 37 has a
rectifier 38 and is directlv and electrically connected to the
secondary coil 26.
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In the illustrated embodiment, when a high negative voltage
or a peak voltage developing at the secondary coil 26 of the
ignition coil 23 is smoothed by the rectifier 38 and a floating
capacity (Cs) of the high voltage application circuit and applied
to the center electrode 32 of the attraction electrode plug 30,
an electric field is provided at or about the spark gap 22 of
the ignition plug 22 through effect of the center electrode 32
which is positioned in the cornbustion chamber 11 whereby the
fuel particles 100 in the lean air-fuel mixture supplied to the
combustion chamber 11 through a suction valve 12 are attracted
towards and accumulate about the inner end 35 of the center
electrode 32. Thus, the fuel particles 100 are attracted toward
and accumulated about the inner end 35 of the center electrode
32 having the electrostatic induction means 36 by the electro-
static induction action of the electric field maintained by the
high voltage application until the fuel particles form the
ignitable lean air-fuel mixture layer 101 about the spark gap
22 of the ignition plug 20.
~ Ihen the ignitable lean air-fuel mixture layer 101 is formed
about the spark gap 22 of the ignition plug 20, the ignitable
lean air-fuel mixture is ignited by the ignition plug 20 through
the ignition circuit 23 thereby causing the lean air-fuel mixture
to explode.
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In the illustrated embodiment, the fuel particles 100 in
the lean air-fuel mixture are attracted and accumulated by the
electrostatic induction action of the electric field provided
by the attraction plug to thereby form the ignitable lean air-fuel
mixture layer 101. Therefore, there is no sudden voltage drop
phenomenon due to the transition from a corona discharge to a
glow discharge in the fuel suction stage by negative pressure
and thus, as more clearly shown in Figs. 4 and 5, the vicinity
of at least the inner end 35 of the attraction electrode plug
is always maintained at a high voltage through the compression,
suction, discharge and expansion strokes of the engine whereby
the fuel particles 100 are attracted towards and held at and
about the spark gap 22 of the ignition plug 20 until the lean air-
fuel mixture within the combustion chamber 11 is ignited and
thus, the lean air-fuel mixture can be positively exploded.
Referring to ~ig. 6, a second embodiment of the attraction
electrode plug of the invention is shown and the attraction - -
electrode plug 30 comprises a metal main body 31 and a center
electrode 32 which extends through the main body 31~
The outer periphery of the lower half portion of the metal
main body 31 is formed with threads 31' by means of which the
attraction electrode plug 30 is secured to the top wall of the
combustion chamber of the cylinder head.
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The center electrode 32 extends through the metal main
body 31 with the opposite ends 33 and 35 thereof extending
out of the main body 31.
One end 33 of the center electrode 32 is electrically
connected to the high voltage application circuit and the
intermediate portion of the center electrode 32 between the
opposite ends thereof is surrounded by an electric insulator
34. The other end 35 of the center electrode 32 is surrounded
by an electrostatic induction means 36 which is integral with
another electric insulator 40.
The attraction electrode plug 30 is secured to the top wall
of the combustion chamber in the cylinder head by inserting the
end 35 surrounded by the electrostatic induction means 36 into
the combustion chamber of the cylinder head and screwing the
threaded portion 31' of the main body 31 into the top ~7all of
the combustion chamber. When a high voltage is applied to the
end 33 of the center electrode 32, an electric field is provided
in the combustion chamber 11 as shown in Fig. 3 and the fuel
particles 100 in the lean air-fuel mixture supplied to the
combustion chamber 11 are attracted towards and accumulate at
and about the end 35 of the center electrode 32 hy the electrostatic
induction action of the electric field.
Fig. 7 shows another embodiment of the present invention
and in this e~bodiment, the electrostatic induction means 36
includes an electrically conductive material 41 whlch surrounds
the end 35 of the center electrode 32.
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Fig. 8 shows another embodiment of the present invention and
in this embodiment, the electrostatic induction means 36 includes
a floating electrode 42 rlade of an electrically conductive
material about the electric insulator 40 which surrounas the
end 35 of the center electrode 32 and the other parts of this
embodiment are substantially similar to the corresponding parts
of the preceding embodiment shown in Fig. 6. The floating
electrode 42 may be provided about the electrically conductive
material-41 as shown in Fig. 7.
Figs. 9 and 10 show another embodiment of the present
invent~on and in this embodiment, the electrostatic induction
means 36 includes an electric insulator 40 surrounding the end
35 of the center electrode 32 and provided with grooves 43 for
receiving fuel particles 100 and the other parts of this
embodiment are substantially similar to the corresponding parts
of the preceding embodiments. The grooves 43 may be provided
in the outer periphery of the electrically conductive material
41 as shown in Fig. 7 or the grooves 43 may be replaced by a
plurality of recesses of a suitable size.
Fig. 11 shows another embodiment o~ the attraction electrode
plug of the present invention and the attraction electrode plug
50 comprises a metal main body 51,- a first center ignition electrode
52, an outer electrode 55 and a second electrostatic center
electrode 57.
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The outer periphery of one half portion of the metal main
body 51 is provided with threads 51' and the attraction electrode
plug 50 is secured to the combustion chamber of the eylinder head
by screwing the threaded portion of the main body 51 into the top
wall of the eylinder head eombustion cham~er.
The first electrode 52 and seeond eleetrode 57 are disposed
within the metal main~body 51 in a spaced relationship to eaeh
other and embedded in an electric insulator 60 positioned within
the metal main body 51.
The first electrode 52 is electrically eonneeted at one end
53 to an ignition eireuit 62 and extends at the other end 54
beyond the adjacent end face of the electric insulator 60.
The outer electrode 55 projects beyond the adjaeent end of
the metal main body 51 and the leading or free end of the outer
: electrode 55 is bent towards the end 54 of the first eleetrode
52 to define a spark gap 56 by the end 54 of the first eleetrode
52 and the outer electrode 55.
: The second electrode 57 is electrically eonnected at one end
58 to a high voltage application circuit 63 and the other end
59 of the second electrode 57 is positioned between the first
electrode 52 and the outer electrode 55 and is formed with an
electrostatic induction means 61 which is surrounded by the
~ electrostatic insulator 60.
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; The attraction electrode plug 50 is mounted in the combustion
chamber by positioning the spark gap 56 and the end S9 of the
second electrode 57 ~hich end is formed with the electrostatic
induction means 61 within the combustion chamber~ When a high
voltage is applied to the second electrode 57, an electric field
is formed about the end 59 of the second electrode 57 to attract
and accumulate the fuel particles in the lean air-~uel mixture
supplied to the combustion chamber towards and about the spark
gap 56 by the electrostatic induction action. The accumulated
fuel particles form an ignitable lean air-fuel mixture layer
whereupon a voltage is applied to the spark gap 56 through the
first electrode 52 to ignite the lean air-fue; mixture. Thus,
the attraction electrode plug 50 has the dual functions of an
inherent attraction electrode plug and an ignition plug.
Fig. 12 shows another embodiment of the lean air-fuel mixture
attraction method according to the present invention. The device
for performing the attraction method generally comprises a
carburetor 70, a main lean air-fuel mixture passage 71, manifolds
72, 73, 74, 75 and cylinders 76, 77, 78 and 79 connected to the
carburetor 70 through the main lean air-fuel mixture passage 71
and manifolds 72, 73, 74, 75, respectively. Attraction electrode
plugs 80, 81, 82, 83 are provided in the manifolds 72, 73, 74,
75, respectively in the upper streams of these manifolds and fuel
concentration measuring means 84, 85, 86, 87 are provided in the
downstreams of the manifolds within the manifolds.
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The attraction electrode plugs 80, 81, 82, 83 serve to
positively attract the fuel particles in the lean air-fuel
mixture distributed into the manifolds 72, 73, 74, 75,
respectively and also feed the fuel particles through the manifolds
along the axes of the manifolds.
The concentration measuring means 84, 85, 86, 87 measure
the concentration of the lean air-fuel mixture within the manifolds
72, 73, 74, 75 and based on the measuring results, the voltage
to be applied to the attraction electrode plugs 80, 81, 82, 83
is controIled in inverse proportion to the concentration to
thereby control the distribution amount of the lean air-fuel
mixture to be attracted to the manifolds 72, 73, 74, 75.
According to the present invention, since the voltage applied
to the attraction electrode plugs 80, 81, 82, 83 is controlled
by the concentration of the lean air-fuel mixture to he fed to the
manifolds 72, 73, 74, 75 and the attraction function of the
attraction electrode plugs 80, 81, 82, 83 is controlled, the
amount of the lean air-fuel mixture to be fed to the cylinders
76, 77, 78, 79 is adjusted whereby the--concentration of the lean
air-fuel mixture is made uniform and the lean air-fuel mixture
is guided along the axes of the manifolds 72, 73, 7~, 75 and the
lean air-fuel mixture is prevented from adhering to the inner
surfaces of the manifold walls.
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~ ig. 13 shows still another embodiment of the lean air-fuel
mixture attraction method according to the present invention.
The device of Fig. 13 is substantially the same as the device of
Fig. 12. However, the device of Fig. 13 is preferred, in certain
situation~ at least, since the attraction electrode plugs and
measuring means are closer to the c~linders~ The device for
performing the attraction method generally comprises a carburetor
70a, a main lean air-fuel mixture passage 71a, relatively short
manifolds 72a, 73a, 74a, 75a and cylinders 76a, 77a, 78a, 79a
connected to the carburetor 70a through the main lean air-fuel
mixture passage 71a and manifolds 72a, 73a, 74a, 75a, respectively.
Attraction electrode plugs 80a, 81a, 82a, 83a are provided in the
manifolds 72a, 73a, 74a, 75a, respectively in the upper streams
of these manifolds and fuel concentration measuring means 84a, 85a,
86a, 87a are provided in the do~nstreams of the manifolds within
the manifolds.
The attraction electrode plugs 80a, 81a, 82a, 83a servé
to positively attract the fuel particles in the lean air-fuel
mixture distributed into the manifolds 72a, 73a, 74a, 75a,
respectively and also feed the fuel particles through the
manifolds along the axes of the manifolds.
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The concentration measuring means 84a, 85a, 86a, 87a measurethe concentration of the lean air-fuel mixture within the
manifolds 72a, 73a, 74a, 75a and based on the measuring results,
the voltage to be applied to the attraction electrode plugs
80a, 81a, 82a, 83a is controlled in inverse proportion to the
concentration to thereby control the distribution amount of the
lean air-fuel mixture to be attracted to the manifolds 72a, 73a,
7aa, 75a.
~ ccording to the present invention, since the voltage
applied to the attraction electrode plugs 80a, 81a, 82a, 83a
is controlled ~y the concentration of the lean air-fuel mixture
to be fed to the manifolds 72a, 73a, 74a, 75a and the attraction
function of the attraction electrode plugs 80a, 81a, 82a, 83a
is controlled, the amount of the lean air-fuel mixture to be fed
to the cylinders 76a, 77a, 78a, 79a is adjustea whereby the
concentration of the lean air-fuel mixture is made uniform
and the lean air-fuel mixture is guided along the axes of the
manifolds 72a, 73a, 74a, 75a and the lean air-fuel mixture is
prevented from adhering to the inner surfaces of the manifold
walls.
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With the above-mentioned construction and function of the
attraction electrode plugs of the present invent.ion, by the
first embodiment of the attraction electrode plug, a uniform
electric field is always provided (an electrostatic field is
provided even in the negative pressure suction stroke) at or
about the spark gap in the combustion chamber, and since the
electric field attracts and accumulates the fuel particles in
the lean air-fuel mixture by the electrostatic induction action
and the lean air-fuel mixture is ignited only after an ignitable
lean air-fuel mixture layer has been formed at and about the spark
gap of :the ignition plug, there are no:disadvantages as seen in
the prior art lean air~fuel mixture ignition methods such as
sudden drop in volta~e to be appl~ed to the corona discharge
electrode plug in the transit from corona discharge to glow
discharge resulting in insufficient attraction of fuel particles
leading to insufficient ignition. The present invention can
positively perform the attraction and accumulation of the fuel
particles in the lean air-fuel mixture, the drawing of the fuel
particles and the ignition of the lean air-fuel mixture.
In the second embodiment of the invention, since the end of
the center electrode positioned in the combustion chamber is formed
with the electrostatic induction means to which a voltage higher
than that applied to the prior art electrode is applied, the
electric field attracts and accumulates the fuel particles in the
lean air-fuel mixture into the combustion chamber and maintains
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the accumulated fuel particles in their attracted condition
and thus the fuel particle attraction method as mentioned
hereinabove can ~e perfectly performed.
In the third embodiment of the present invention, since
the single metal main body includes the first electrode and
the outer electrode forming the spark gap with the second
electrode forming the attraction electrode plug, the single
electrode asse~bly concurrently performs as the ignition plug
and attraction electrode plug.
In the fourth embodiment of the present invention, the
attraction electrode plugs are disposed adjacent to the
connection between the main lean air-fuel mixture passage and
the manifolds in the upper streams within the manifolds and the
voltage applied to the attraction electrode plug is controlled
so as to make the concentration of the lean air-fuel mixture
uniform to thereby adjust the amount of the lean air-fuel mixture
fed to the cylinders and equalize the concentration of the lean
air-fuel mixture. And the fuel particles in the lean air-fuel
mixture supplied to the manifolds are fed alon~ the axes of the
manifolds by the attraction action of the attraction electrode
plugs whereby adhering of the fuel particles to the walls of the
manifolds can be prevented.
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