U.S. patent number 3,797,240 [Application Number 05/222,900] was granted by the patent office on 1974-03-19 for exhaust emission control device.
This patent grant is currently assigned to Nippon Denso Kabushiki Kaisha, Toyota Jidosha Kogyo Kabushiki Kaisha. Invention is credited to Tokuta Inoue, Shunzo Yamaguchi.
United States Patent |
3,797,240 |
Inoue , et al. |
March 19, 1974 |
EXHAUST EMISSION CONTROL DEVICE
Abstract
This invention relates to an exhaust emission control device. A
vortical combustion chamber extends into an oxidation reaction
chamber so that the exhaust gases introduced into the oxidation
reaction chamber through the exhaust manifold may be brought into
direct contact with the outer wall surfaces of the vortical
combustion chamber.
Inventors: |
Inoue; Tokuta (Susono,
JA), Yamaguchi; Shunzo (Susono, JA) |
Assignee: |
Toyota Jidosha Kogyo Kabushiki
Kaisha (Aichi-ken, JA)
Nippon Denso Kabushiki Kaisha (Kariya-shi,
JA)
|
Family
ID: |
12535980 |
Appl.
No.: |
05/222,900 |
Filed: |
February 2, 1972 |
Foreign Application Priority Data
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|
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Jun 2, 1971 [JA] |
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46-38824 |
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Current U.S.
Class: |
60/303;
422/168 |
Current CPC
Class: |
F01N
3/26 (20130101); F01N 3/38 (20130101) |
Current International
Class: |
F01N
3/26 (20060101); F01N 3/38 (20060101); F01n
003/14 () |
Field of
Search: |
;60/286,303
;23/277C |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Hart; Douglas
Attorney, Agent or Firm: Stevens, Davis, Miller &
Mosher
Claims
What is claimed is:
1. In an exhaust emission control device comprising an oxidation
reaction chamber connected to an exhaust manifold of an internal
combustion engine to receive exhaust gases therefrom, and a
vortical combustion chamber receiving a supply of secondary air and
secondary fuel to produce an air-fuel mixture therein which is
ignited to burn in flames in vortical form, said flames in vortical
form being blown from said vortical combustion chamber into said
oxidation reaction chamber so as to subject unburned components of
the exhaust gases in the oxidation reaction chamber to
recombustion, the improvement in that at least a portion of said
vortical combustion chamber extends into said oxidation reaction
chamber so that the exhaust gases introduced into said oxidation
reaction chamber through said exhaust manifold may be brought into
direct contact with outer wall surfaces of the vortical combustion
chamber, and wherein fuel vaporizers made of a heat resisting
porous material comprise a central fuel exit portion and peripheral
fuel exit portion of one wall of said vortical combustion chamber
so as to facilitate vaporization of the secondary fuel in the
vortical combustion chamber.
2. The exhaust emission control device of claim 1, wherein said
central fuel exit portion is disposed around an ignition means.
3. An exhaust emission control device comprising:
an oxidation reaction chamber for receiving exhaust gases from an
internal combustion engine:
a cylindrical vortical combustion chamber having means for
introducing secondary fuel thereto and means for introducing
secondary air thereto tangentially to the inner surface of said
cylindrical chamber, for producing an air-fuel mixture therein for
burning in a vortical flame blown from said vortical chamber
through an open end thereof into said oxidation reaction chamber
for subjecting unburned components of said exhaust gases to
recombustion,
said cylindrical vortical combustion chamber extending along the
direction of its axis into said oxidation reaction chamber, and the
outside surface of said vortical chamber being adjacent an exhaust
gas inlet opening in said oxidation reaction chamber, for directly
contacting exhaust gases entering said reaction chamber with said
outside surface of said vortical chamber, and
a fuel vaporizer of heat resistant porous material at a closed end
of said cylindrical vortical combustion chamber, said vaporizer
comprising a central fuel exit portion near the axis of said
cylindrical chamber and a peripheral fuel exit portion near the
inner surface of said cylindrical chamber.
4. The exhaust emission control device of claim 3 wherein said
oxidation reaction chamber is also cylindrical, and said
cylindrical oxidation reaction chamber and said cylindrical
vortical combustion chamber are substantially coaxial.
5. The exhaust emission control device of claim 3, wherein said
central fuel exit portion is disposed around an ignition means.
Description
This invention relates to an exhaust emission control device for
internal combustion engines for motor vehicles or the like designed
to subject unburned noxious components of exhaust gases of such
engines to recombustion to remove such noxious components from the
exhaust gases.
In one type of exhaust emission control device known in the art in
which exhaust gases of an internal combustion engine are subjected
to recombustion in an oxidation reaction chamber, a supply of
secondary fuel is delivered to a cylindrical combustion chamber
disposed adjacent the oxidation reaction chamber, and a supply of
secondary air is injected into the cylindrical combustion chamber
tangentially thereto to produce a forced vortex flow of the
air-fuel mixture in a central portion of the cylindrical combustion
chamber and natural vortex flows of the air-fuel mixture in outer
peripheral portions of the combustion chamber. Flames are produced
in cylindrical form by igniting the air-fuel mixture in such forced
vortex flows, and blown through an opening or pipe into the
oxidation reaction chamber where a mixture of exhaust gases and
excess air is ignited by such flames in cylindrical form to subject
the exhaust gases to recombustion, thereby removing unburned
noxious components of the exhaust gases before they are vented to
the atmosphere.
Some disadvantages are associated with the exhaust emission control
device of this type. In the conventional exhaust emission control
device of the type described, the oxidation reaction chamber and
the cylindrical combustion chamber are separated from each other,
and the flames produced in the cylindrical combustion chamber are
blown into the oxidation reaction chamber. Thus, wall surfaces of
the reaction chamber remain cool for a while after the internal
combustion engine is started, thereby delaying the ignition of the
exhaust gases in the oxidation reaction chamber by the flames from
the cylindrical combustion chamber. This may result in an
incomplete oxidation reaction taking place in the exhaust gases,
thereby achieving little or no result in removing noxious unburned
components from the exhaust gases.
Besides, after the exhaust gases are ignited, complete combustion
of the exhaust gases may not be possible in the oxidation reaction
chamber due to large variations in the quantities of exhaust gases,
particularly of unburned components of the exhaust gases when the
engine is in a transient condition as the time of rapid
acceleration of the engine.
This invention has as its object the provision of a device which is
capable of effecting perfect exhaust emission control even if
quantities of exhaust gases, particularly of unburned noxious
components of exhaust gases therein, undergo large fluctuations as
when the internal combustion engine is started or accelerated
rapidly.
This invention permits effecting exhaust emission control
satisfactorily by obviating the aforementioned disadvantages of the
prior art by the features as set forth in the claims appended
hereto.
Other and additional objects are those inherent in the invention
hereinafter shown, described and claimed, and will become evident
as the description proceeds.
In the drawings:
FIG. 1 is a schematic side view of the exhaust emission control
device according to this invention as incorporated in an internal
combustion engine of a motor vehicle; and
FIG. 2 is a vertical sectional view, on an enlarged scale, of the
oxidation reaction chamber of the device.
FIG. 3 is an enlarged sectional view of the fuel vaporizer of FIG.
2.
In FIG. 1, an exhaust manifold 12 connected at one end to exhaust
ports 11 of an internal combustion engine 30 is connected at the
other end to an oxidation reaction chamber 10 which is provided
with an exhaust pipe 13 for venting purified exhaust gases to the
atmosphere.
In FIG. 2, a vortical combustion chamber 20 is mounted at an end of
oxidation reaction chamber 10 opposite to the end thereof at which
exhaust pipe 13 is provided. Vortical combustion chamber 20 has a
portion 17 which extends into the interior of oxidation reaction
chamber 10 and which is formed with a flame ejection port 16 in a
wall thereof with respect to the interior of oxidation reaction
chamber 10. Exhaust manifold 12 opens at an opening 18 thereof in
oxidation reaction chamber 10 which is disposed in a position such
that the exhaust gases introduced into oxidation reaction chamber
10 through exhaust manifold 12 are brought into direct contact with
the portion 17 of vortical combustion chamber 20.
As shown in FIG. 1, an air pump 19 operated by internal combustion
engine 30 or an electric motor is connected to exhaust manifold 12
and vortical combustion chamber 20 by air lines 14 and 15
respectively, air line 15 being tangentially connected to a base of
vortical combustion chamber 20 through an opening 22 thereof to
supply secondary air tangentially to the base of vortical
combustion chamber 20.
In FIG. 2 and 3, fuel vaporizers 24 and 25 made of a heat resisting
porous material, such for example as sintered metal, are provided
in a central portion and peripheral portion of a surface of a wall
23 of vortical combustion chamber 20 opposite to the wall in which
flame ejection port 16 is formed, and connected through a fuel line
26 and a fuel pump 29 shown in FIG. 1 to a secondary fuel supply
source (not shown). An ignition plug 27 is mounted in the central
portion of wall 23.
In operation, air pump 19 and fuel pump 29 are operated when
internal combustion engine 30 is started. Secondary air is
tangentially supplied through the opening 22 of air line 15 into
vortical combustion chamber 20 and formed into vortex flows in the
vortical combustion chamber comprising forced vortex flows in a
central portion of the chamber and natural vortex flows in
peripheral portions of the chamber. At the same time, secondary air
is supplied through fuel line 26 to fuel vaporizers 24 and 25 which
are impregnated with the secondary fuel. The secondary fuel with
which vaporizers 24 and 25 are impregnated is vaporized by the
flows of the secondary air to produce an air-fuel mixture.
The air-fuel mixture is ignited by ignition plug 27 such that first
the air-fuel mixture in forced vortex flows is ignited, and then
the air-fuel mixture in natural vortex flows is ignited till all
the air-fuel mixture in vortical combustion chamber 20 is ignited
and burns. Thus, combustion of the air-fuel mixture takes place
vigorously in vortical combustion chamber 20 and the outer wall
surfaces of the chamber are rapidly heated.
On the other hand, exhaust gases are introduced through the opening
18 of exhaust manifold 12 into oxidation reaction chamber 10. When
necessary, secondary air supplied through air line 14 is introduced
into oxidation reaction chamber 10 together with the exhaust gases.
The exhaust gases with or without secondary air are brought into
direct contact with the outer wall surfaces of vortical combustion
chamber 20, and unburned noxious components thereof at once undergo
oxidation reaction and are readily burned by flames in cylindrical
form ejected through flame ejection port 16 into oxidation reaction
chamber 10.
Unburned noxious components of exhaust gases, such for example as
carbon monoxide, hydrocarbons and the like, are burned completely
in this way so that the exhaust gases are rendered innocuous and
vented to the atmosphere through exhaust pipe 13.
In the aforementioned construction and operation of the device
according to this invention, any shape as desired may be given to
the vortex flows in vortical combustion chamber 20 by suitably
selecting the shape of flame ejection port 16. It is to be
understood that the vortical combustion chamber may be of any form
as desired so long as its outer wall surfaces can be maintained at
elevated temperatures or in a red hot state.
In the aforementioned embodiment of this invention, the body of the
vortical combustion chamber extends into the oxidation reaction
chamber. This arrangement permits a high efficiency in exhaust
emission control immediately after the internal combustion engine
is started, in spite of the fact that the temperature of exhaust
gases introduced into the exhaust emission control device is low
because the internal combustion engine, exhaust manifold and
oxidation reaction chamber are cool at the time the engine is
started. The exhaust gases introduced into the oxidation reaction
chamber are immediately warmed and ignited because they are brought
into direct contact with the red hot outer wall surface of the
vortical combustion chamber.
The aforementioned embodiment of this invention also permits
complete combustion of unburned noxious components of exhaust gases
to take place even in cases where the conventional exhaust emission
control device is unable to maintain combustion of exhaust gases in
the oxidation reaction chamber because a sudden increase in the
quantity of exhaust gases cools off the exhaust gases and reduces
the proportions of unburned noxious components in the exhaust gases
as when engine speed is rapidly increased.
In the aforementioned embodiment of this invention, fuel vaporizers
made of a heat resisting porous material are provided in a central
and peripheral portion of one wall of the vortical combustion
chamber. This arrangement is effective first to positively ignite
the air-fuel mixture in forced flows in the central portion of the
vortical combustion chamber and then to ignite the air-fuel mixture
in natural vortex flows in the peripheral portions thereof. This
makes it possible to heat the outer wall surfaces of the vortical
combustion chamber to a red hot state in a short interval of
time.
* * * * *