United States Patent [191
`Takada et al.
`
`[11]
`
`[45]
`
`4,276,745
`Jul. 7, 1981
`
`[54] EXHAUST GAS CONTROL APPARATUS
`[75]
`Inventors: Shigetaka Takada, Ohbu; Kazumichi
`Naruse; Yukihiro Watanabe, both of
`Nagoya, all of Japan
`[73] Assignee: Aisan Industry Co., Ltd., Aichi,
`Japan
`[21] Appl. No.: 56,759
`(22] Filed:
`Jul. 12, 1979
`[51]
`Int. Cl,3 ................................................ FOlN 3/10
`[52] u.s. Cl ......................................... 60/276; 60/289;
`60/307;417/471
`[58] Field of Search .................. 417/471; 60/307, 276,
`60/290, 289
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`1,883,459 10/1932
`Avigdor ............................... 417/471
`3,203,168
`8/1965
`Thomas .................................. 60/286
`3,986,352 10/1976
`Casey ... .................................. 60/289
`
`4,068,472
`4,099,377
`4,149,376
`
`1/1978
`7/1978
`4/1979
`
`Takata .................................... 60/290
`Yoshimura ............................. 60/289
`Masaki ................................... 60/290
`
`FOREIGN PATENT DOCUMENTS
`52-18519 2/1977 Japan ......................................... 60/307
`
`Primary Examiner-Douglas Hart
`
`ABSTRACT
`[57]
`An improved exhaust gas control apparatus, which
`utilizes a 3-way catalyst for reducing the contents of
`harmful components in exhaust gas, incorporates a dia(cid:173)
`phragm type air pump for supplying secondary air,
`upstream of the catalyst, to the exhaust gas. A chamber,
`which is formed on one side of the diaphragm in the air
`pump, is communicated through an electromagnetic
`changeover va!ve with the upstream side of the cata(cid:173)
`lyst.
`
`9 Claims, 2 Drawing Figures
`
`BOSCH-DAIMLER EXHIBIT 1005
`
`Page 1 of 5
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`

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`'.J ,, ,,
`11 ,, ,, ,, ,, ,,
`t_l..-- --
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`I
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`I
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`U.S. Patent
`
`Jul. 7, 1981
`
`.FIG. I
`
`4,276,745
`
`' , t I
`
`40
`
`FIG. 2
`
`59
`
`Page 2 of 5
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`

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`1
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`4,276,745
`
`EXHAUST GAS CONTROL APPARATUS
`
`BACKGROUND OF THE INVENTION
`This invention relates to an apparatus for controlling 5
`exhaust gas discharged from an internal combustion
`engine, and more particularly to an apparatus which is
`used for control of the exhaust gas in a closed loop in
`which the air-fuel ratio of the gas mix in the carburetor
`is so controlled by means of signals from an exhaust gas 10
`sensor that the air-fuel ratio is always maintained close
`to a theoretical air-fuel ratio in order to effectively
`utilize a (exhaust gas purification) cleaning function of a
`3-way catalyst, and which is adapted to supply, during
`the idle mode and during the cold mode of the engine, 15
`secondary air to the gas mix in a region between the
`exhaust gas sensor and the 3-way catalyst.
`The 3-way catalyst has been used as means for simul(cid:173)
`taneously reducing the contents of three harmful com(cid:173)
`ponents, NOx, HC and CO contained in the exhaust gas 20
`discharge from internal combustion engines. For utiliz(cid:173)
`ing the 3-way catalyst in the most efficient manner, it is
`necessary to precisely control the air-fuel ratio of the
`gas mix being supplied to an engine so that the air-fuel
`ratio of the gas mix may be maintained as close to the 25
`theoretical air-fuel ratio as possible. For this purpose, an
`air-fuel ratio control apparatus of feedback type has
`been developed. With this conventional control appara(cid:173)
`tus, however, there are some cases where the cleaning
`function of the 3-way catalyst cannot be effectively 30
`obtained For example, in the case of a transition from
`the idle mode to the acceleration mode or during the
`shifting of the gears, the control is unable to follow a
`rapid variation in the air-fuel ratio. In the case of a cold
`start or in the case of a long time idling, the temperature 35
`of the exhaust gas sensor decreases resulting in an in(cid:173)
`creased internal impedance, thus making the normal
`control impossible to be obtained. As a result, large
`amounts of the harmful components, especially CO,
`may be discharged in the air. For preventing this, a 40
`system has been proposed wherein, at the time of idle or
`gear shift, for example, secondary air is supplied up(cid:173)
`stream of the 3-way catalyst to the exhaust gas to dilute
`the gas so that the 3-way catalyst can function in an
`oxidizing region, thereby to effectively eliminate CO .. 45
`As means for supplying such secondary air, an air sup(cid:173)
`ply device, which comprises an air pump of a vane type
`and an electromagnetic three-way valve, has been em(cid:173)
`ployed. In this system, however, since the air pump is
`driven through rotation of the engine, a part of the 50
`output of the engine is consumed in the air pump, result(cid:173)
`ing in a decreased effective output qf engine. Especially
`in a region of the running mode which requires the
`maximum output, a decrease in the effective output is
`significant because of an increased pressure of the ex- 55
`haust gas and an increased load put on the air pump.
`
`SUMMARY OF THE INVENTION
`The invention has been accomplished because of the
`above-described problems in the prior art.
`A-ccordingly, an object of the invention is to provide
`an improved exhaust gas control apparatus.
`According to the invention, an air supply device is
`communicated with a chamber, which is formed on one
`side of the diaphragm in a diaphragm type fuel pump, 65
`through an air intake port and an air discharge port
`communicating with the chamber, the diaphragm being
`driven by a rocker arm in an interlocked manner with
`
`60
`
`2
`the drive shaft of engine. The air discharge port is com(cid:173)
`municated through an electromagnetic valve to the
`upstream side of 3-way catalyst. With such diaphragm
`type air pump, secondary air can be supplied to the
`exhaust gas to reduce discharged amounts of CO with(cid:173)
`out causing a decrease in the output of the engine, as
`compared with the conventional vane type air pump.
`The above and other objects, features and advantages
`of the invention will become apparent from the follow(cid:173)
`ing detailed description of a preferred embodiment
`thereof made in connection with the accompanying
`drawings.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 schematically shows, partially in section, an
`exhaust gas control system according to the invention;
`and
`FIG. 2 is a sectional view of a diaphragm type air
`pump used in the system of FIG. 1.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`The invention will now be described in connection
`with a preferred embodiment thereof while making
`reference to the drawings. Referring now to FIG. 1
`which illustrates an embodiment of the invention, there
`are shown an engine 10, a suction manifold 11 thereto,
`an exhaust manifold 12 therefrom, an exhaust gas sensor
`13 disposed in the latter, and portion containing a 3-way
`catalyst 14 communicating with the exhaust gas mani(cid:173)
`fold 11. A water temperature switch 15 is provided in
`the water jacket of the engine. A carburetor 20 has an
`air bleed control port 21 for a main metering system,
`and an air bleed control port 22 for a slow speed system.
`An idling detection switch 23 is provided which coop(cid:173)
`erates with a switch member mounted jointly to the
`throttle valve, an air cleaner 24 communicates with the
`intake passage of the carburetor. A control circuit 30 is
`connected to the exhaust gas sensor 13 and to actuators
`40 and to an electromagnetic change-over valve 60
`which is connected to a diaphragm type air pump SO.
`FIG. 2 illustrates in detail the construction of the dia(cid:173)
`phragm type air pump SO. Referring now to FIG. 2, on
`one side of a diaphragm 52 is formed a diaphragm
`chamber 51, and, on the other side of the diaphragm 52
`is formed a fuel chamber 51'. The diaphragm chamber
`51 has an air intake port 53 and an air discharge port 54
`which are provided with a bevel valve 55 and a bevel
`valve 56, respectively. The fuel chamber 51' is commu(cid:173)
`nicated with a fuel intake port 59 through a check valve
`57, and with a fuel discharge port 59' through a check
`valve 58. The numeral 51' indicates a rocker arm.
`Normally, the control circuit 30 actuates, due to sig(cid:173)
`nals given from the exhaust gas sensor 13, the actuators
`40 for controlling amounts of bleed airs in the main
`metering system and in the slow speed system, thereby
`controlling the air-fuel ratio of the gas mix, which is to
`be supplied to the engine 10, so that air-fuel ratio of the
`gas mix may be maintained close to the theoretical air(cid:173)
`fuel ratio, while the 3-way characteristic of the 3-way
`catalyst 14 is utilized 'for effectively reducing dis(cid:173)
`charged amounts of the three harmful components
`NOx, CO and HC.
`When the rocker arm 51" is pushed by a cam (not
`shown) driven by the drive shaft of the engine, the
`diaphragm 52 is moved downwardly, and fuel is intro(cid:173)
`duced from the fuel intake port 59, passes through the
`
`Page 3 of 5
`
`

`

`25
`
`3
`check valve 57, which is provided on the fuel inlet, and
`flows into the fuel chamber 51'. At the same time, the
`bevel valve 55, which is provided on the air intake port,
`is closed, and thus air in the diaphragm chamber 51 is
`compressed and is discharged out therefrom by forcing 5
`the bevel valve 56, which is provided on the air dis(cid:173)
`charge port, to open. When the locker arm 51" is re(cid:173)
`leased from the cam, the diaphragm 52 is moved up(cid:173)
`ward by a diaphragm spring S, pressure of the fuel in
`the fuel chamber 51' is increased and the fuel is dis- 10
`charged from the fuel discharged port 59' through the
`check valve 58 which is provided on the fuel outlet. At
`the same time, pressure in the diaphragm chamber 51
`becomes negative, the bevel valve 56, which is pro(cid:173)
`vided on the air discharge port, is closed, the bevel 15
`valve 55, which is provided on the air intake port, is
`opened, and air is introduced through the air intake port
`53 into the diaphragm chamber 51. When a signal is
`applied from the water temperature switch 15 or the
`idling detection switch 23, the control circuit 30 applies 20
`an ON/OFF signal to the electromagnetic changeover
`switch 60. When the changeover valve 60 is turned to
`ON, air, which is sent therein from the air pump 50 via
`conduit 50a, is sent to the upstream side of the 3-way
`catalyst 14 and conduit 60a. When the changeover
`valve 60 is turned to OFF, air, which is sent in there
`from the air pump 50 via conduit 50a, is sent to the air
`cleaner 24 via conduit 60b.
`As will be apparent from the above description, ac(cid:173)
`cording to the invention, secondary air is supplied,
`depending on the idling signal and the water tempera- 30
`ture signal, to the upstream side of the 3-way catalyst
`for reducing the CO content, thus satisfactorily effect(cid:173)
`ing the original performance of the catalyst, while al(cid:173)
`lowing the air pump to perform its function without
`degrading the function of the conventional mechanical 35
`fuel pump. Accordingly, a large amount of surplus in
`output can be obtained with an apparatus which is
`smaller in size and lighter in weight as compared with
`the prior art apparatus; thus an increased loading capac(cid:173)
`ity and a reduction in fuel cost is obtained. Further, cost 40
`can be reduced as compared with the conventional air
`pump.
`While the invention has been described in connection
`with the preferred embodiment thereof, it should be
`understood that the invention is not limited to the above 45
`and various changes and modifications can be made
`without departing from the spirit and scope of the in(cid:173)
`vention.
`What is claimed is:
`1. In an exhaust gas control apparatus having an ex- 50
`haust gas sensor means, disposed in the exhaust system
`of an internal combustion engine having an engine shaft,
`for detecting the air-fuel ratio of an air-fuel mixture
`supplied to the engine, a carburetor supplying an air(cid:173)
`fuel mixture to the engine having main and slow sys- 55
`terns and an air cleaner upstream of the carburetor,
`temperature detector means for detecting a non-warm
`condition of the engine, actuator means disposed in the
`main and slow systems of the carburetor for controlling
`the air-fuel ratio of the mixture supplied to the engine, 60
`control circuit means for driving said actuator means in
`accordance with a signal from the exhaust gas sensor, a
`3-way catalyst disposed in the exhaust system at a
`downstream side of said exhaust gas sensor, idle detec(cid:173)
`tor means for detecting an idle condition of the engine, 65
`an air supply means for supplying secondary air to the
`exhaust system at an upstream side of said 3-way cata(cid:173)
`lyst in accordance with a signal from the temperature
`
`4,276,745
`
`4
`detector means for detecting the non-warm condition of
`the engine, the improvement wherein
`said air supply means comprises a diaphragm type
`fuel pump means, having a diaphragm and a rocker
`arm operatively connected thereto, for being
`driven by the engine shaft via said rocker arm,
`said detector means are connected to said control
`circuit means,
`said air supply means defining a chamber at one side
`of the diaphragm and having an air inlet port and
`air discharge port communicating therewith,
`change-over solenoid valve means for being driven
`by said control circuit means in accordance with
`signals from said detector means and for communi(cid:173)
`cating therethrough said air discharge port with
`the upstream side of the 3-way catalyst and the air
`cleaner respectively.
`2. The exhaust gas control apparatus according to
`claim 1, wherein
`said diaphragm type fuel pump means includes,
`a displaceable rod connected at one end to said dia(cid:173)
`phragm and at another end to said rocker and con(cid:173)
`stituting means for moving said diaphragm, an(cid:173)
`other chamber being defined at the other side of the
`diaphragm and having a fuel intake port and a fuel
`discharge port communicating therewith,
`oppositely acting check valves disposed in said an(cid:173)
`other chamber and communicating with said fuel
`intake port and said fuel discharge port, respec(cid:173)
`tively.
`3. The exhaust gas control apparatus according to
`claim 2, further comprising
`oppositely acting bevel valves disposed in said first(cid:173)
`mentioned chamber communicating with said air
`intake port and said air discharge port, respec-
`tively.
`·
`4. The exhaust gas control apparatus according to
`claims 1, 2 or 3, further comprising
`spring means for biasing said diaphragm.
`5. The exhaust gas control apparatus according to
`claim 2, further comprising
`first spring means for biasing the said another end of
`said rod.
`6. The exhaust gas control apparatus according to
`claim 1, wherein
`said air supply means communicates with the exhaust
`system between the 3-way catalyst and the exhaust
`gas sensor means.
`7. The exhaust gas control apparatus according to
`claim 1, wherein
`said air intake port communicates with the air
`cleaner.
`8. The exhaust gas control apparatus according to
`claim 1, wherein
`said change-over solenoid valve means for switching
`over to connect said air discharge port with said
`upstream side of the 3-way catalyst when said tem(cid:173)
`perature detector means detects the non-warm
`condition and said idle detector means detects the
`idle condition, respectively.
`9. The exhaust gas control apparatus according to
`claim 1, further comprising
`a throttle valve at the carburetor,
`said temperature detector means is an engine water
`switch,
`said idle detector means comprises a member con(cid:173)
`nected jointly to said throttle valve and a switch
`cooperating with said member.
`* * * * *
`
`Page 4 of 5
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`

`

`UNITED STATES PATENT AND TRADEMARK OFFICE
`CERTIFICATE O:F CORRECTION
`4,276,745
`July 7, 1981
`Shigetaka Takada et al
`
`PATENTNO.
`DATED
`
`:
`
`INVENTOR(S) :
`
`It is certified that error appears in the above-identified patent and that said Letters Patent
`are hereby corrected as shown below:
`
`Insert on the first page:
`
`--[30] Foreign Application Pr~ority Data
`
`Aug. 7, 1978 [JP] Japan 95997/1978--
`
`In Item [75]
`
`delete 11 0hbu 11 and change 11 both of Nagoya,
`
`II
`
`to read --all of AICHI,--
`5igncd and 5calcd this
`Sixth Day of OctoiH; 1981
`
`Attest:
`
`ISE:ALJ
`
`-1t
`
`~~·
`
`Attesting Ojficer
`
`Commissioner of Patents and Trademarks
`
`GERALD J. MOSSINGHOFF
`
`•
`
`\
`
`Page 5 of 5
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`