CA1067014A - Exhaust gas purifier of an internal combustion engine - Google Patents
Exhaust gas purifier of an internal combustion engineInfo
- Publication number
- CA1067014A CA1067014A CA249,761A CA249761A CA1067014A CA 1067014 A CA1067014 A CA 1067014A CA 249761 A CA249761 A CA 249761A CA 1067014 A CA1067014 A CA 1067014A
- Authority
- CA
- Canada
- Prior art keywords
- exhaust
- cylinders
- exhaust gas
- valve
- gas purifier
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
- F01N3/30—Arrangements for supply of additional air
- F01N3/34—Arrangements for supply of additional air using air conduits or jet air pumps, e.g. near the engine exhaust port
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
- F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
- F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
- F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
- F01N3/30—Arrangements for supply of additional air
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/02—Engines characterised by their cycles, e.g. six-stroke
- F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
- F02B2075/027—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle four
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
- F02B75/18—Multi-cylinder engines
- F02B2075/1804—Number of cylinders
- F02B2075/1812—Number of cylinders three
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
- F02B75/18—Multi-cylinder engines
- F02B2075/1804—Number of cylinders
- F02B2075/182—Number of cylinders five
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
- F02B75/18—Multi-cylinder engines
- F02B2075/1804—Number of cylinders
- F02B2075/1824—Number of cylinders six
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
- F02B75/18—Multi-cylinder engines
- F02B75/20—Multi-cylinder engines with cylinders all in one line
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Exhaust Gas After Treatment (AREA)
- Exhaust-Gas Circulating Devices (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
Abstract
AN EXHAUST GAS PURIFIER OF
AN INTERNAL COMBUSTION ENGINE
ABSTRACT OF THE DISCLOSURE
An exhaust gas purifier of a four-stroke internal combustion engine has a plurality of cylinders consisting of cylinder groups, each of which has at least two cylinders, and the opening durations of the exhaust valves in any one group do not overlap. The exhaust passages of the cylinders of one of the cylinder groups are connected to the atmos-phere via a common reed valve.
AN INTERNAL COMBUSTION ENGINE
ABSTRACT OF THE DISCLOSURE
An exhaust gas purifier of a four-stroke internal combustion engine has a plurality of cylinders consisting of cylinder groups, each of which has at least two cylinders, and the opening durations of the exhaust valves in any one group do not overlap. The exhaust passages of the cylinders of one of the cylinder groups are connected to the atmos-phere via a common reed valve.
Description
~C)6~0~4 DESCRIPTION OF TH~ I~VENTION
~he present invention relates to an exhaust gas ~ purifier of an internal combustion engine.
Known internal combustion engines are provided with exhaust gas purifiers which use catalytic con~erters for eliminating harmful components from the exhaust gas, for example unburned gases HC and CO. In conventional catalytic converters of this type, a secondary air is fed to the catalytic converter by means of the secondary air feed pump driven by ~he engine and thus the oxidation of unburned HC and Co is promoted in the catalytic converter, thereby eliminating harmful components from the exhaust gas.
Consequently, conventional exhaust gas purifiers need to be provided with the secondary air feed pump.
An object of the present invention is to provide an improved exhaust gas purifier of a simple construction without the above-mentioned secondary air feed pump.
~ccording to the present invention, an improved ; exhaust gas purifier in a Eour-stroke internal combustion engine having a plurality of cylinders each having an intake valve, an exhaust valve and an exhaust passage, said cylinders being arranged in cylinder groups each of which group comprises at least two cylinders, the opening durations of the exhaust valves in any one group not overlapping, wherein the improvement comprises;
at least one air passage for connecting the exhaust passages of the cylinders of one of said cylinder groups with the atmosphere, and a valve means disposed in said air passage and arranged to open automatically in response to a decrease
~he present invention relates to an exhaust gas ~ purifier of an internal combustion engine.
Known internal combustion engines are provided with exhaust gas purifiers which use catalytic con~erters for eliminating harmful components from the exhaust gas, for example unburned gases HC and CO. In conventional catalytic converters of this type, a secondary air is fed to the catalytic converter by means of the secondary air feed pump driven by ~he engine and thus the oxidation of unburned HC and Co is promoted in the catalytic converter, thereby eliminating harmful components from the exhaust gas.
Consequently, conventional exhaust gas purifiers need to be provided with the secondary air feed pump.
An object of the present invention is to provide an improved exhaust gas purifier of a simple construction without the above-mentioned secondary air feed pump.
~ccording to the present invention, an improved ; exhaust gas purifier in a Eour-stroke internal combustion engine having a plurality of cylinders each having an intake valve, an exhaust valve and an exhaust passage, said cylinders being arranged in cylinder groups each of which group comprises at least two cylinders, the opening durations of the exhaust valves in any one group not overlapping, wherein the improvement comprises;
at least one air passage for connecting the exhaust passages of the cylinders of one of said cylinder groups with the atmosphere, and a valve means disposed in said air passage and arranged to open automatically in response to a decrease
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in pressure below a predetermined value in the exhaust passages of the cylinders of said one cylinder group to permit the supply of an air into the exhaust passages of ; the cylinders of said one cylinder group.
The above-mentioned object of the invention may be more fully understood from the following description of a preferred embodiment of the invention and from the accom-panying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Fig. 1 is a schematic plane view of an internal t combustion engine having the exhaust gas purifier according to the present invention;
Fig. 2 is a cross-sectional view taken along the line II-II in Fig. l;
Fig. 3 is a view showing intake- and exhaust-valve timing;
Fig. 4 is a view showing valve lifts of an intake valve and an exhaust valve of each cylinder in a four-cylinder engine;
Fig. 5 is a schematic plane view of an embodiment showing the possible combinations of the cylinders which the branch conduits should be connected to;
Fig. 6 is a view similar to Fig. 5, showing j 25 another embodiment;
Fig. 7 is a view similar to Fig. 5, showing the other embodiment;
Fig. 8 is a view showing valve lifts of an intake valve and an exhaust valve of each cylinder in a six-cylinder engine;
. - 3 -10670~4 Fig. 9 is a schematic plane view of an embodiment showing the various possible combinations of cylinders which the branch conduits should be connected to;
Fig. 10 is a view similar to Fig. 9, showing another embodiment, and;
Fig. 11 is a pxospective view of the reed valve.
DESCRIPTION OF A PREFERRED EMBODIMENT
Fig. 1 shows a schematic plane view of the internal combustion engine having the exhaust gas purifier according to the present invention and Fig. 2 shows a cross-sectional view of a part of the engine shown in Fig. 1.
Referring to Figs. 1 and 2, the internal combustion engine comprises a cylinder block 1, a piston 3 reciprocatively movable in the cylinder 2 formed in the cylinder block 1, a cylinder head 4 fixed onto the cylinaer block 1, an intake valve (not shown), an exhaust valve 6 for controlling the opening and closing operation of an exhaust port 5, an exhaust manifold 7 and an intake manifold 8 which are fixed onto the cylinder head 4, an air cleaner 9 mounted on the intake manifold 8 and a catalytic converter 10.
-The gas to be exhausted which has been burned in a combustion ; chamber 11 is delivered into the catalytic converter 10 through the exhaust manifold 7, and then, the gas cleaned in the catalytic converter 10 is delivered to the atmosphere.
Fig. 3 shows the intake- and exhaust-valve timing.
In a conventional internal combustion engine having the intake valve and the exhaust valve, a duration of overlap between the intake valve and the exhaust valve occurs during which both the intake and the exhaust valves are each in an opened position immediately before the exhaust .. . , . . . . . .. ~ ... .
,1 .
valve is closed. As in shown in Fig. 3, for example, the exhaust valve A opens 50 before BDC (Bottom dead center) and closes 16D after TDC (Top dead center), and the intake valve B opens 16 before TDC and closes 50 after BDC.
Consequently, as is shown by arrow C, a duration of overlap occurs when both exhaust valve A and the intake valve B
are each in an opened position.
In Fig. 2, assuming that the engine is in an exhaust stroke position during which the exhaust valve 6 is in an opened position, tha gas to be exhausted in the combustion chamber 11 is delivered into the catalytic converter 10 ' via the exhaust valve port 5, the exhaust port 12 and the exhaust manifold 7 as the piston 3 is moved upwords in the ; cylinder 2. At this time, the pressure in the exhaust - lS port 12 and in the branch portion of the exhaust manifold 7 is greater than the atmospheric pressure. Then, when the intake valve opens and piston 3 is further moved upwards so as to reach its uppermost position (TDC), the pressure in the exhaust port 12 and in the branch portion of the exhaust manifold 7 becomes substantially the same as the atmospheric pressure. Then, when the piston 3 begins to move downwards, the fuel mixture is sucked into the combustion chamber 11 via the intake port (not shown).
At this time, the exhaust valve 6 is still in an opened ; 25 position. Thus, a part of the exhaust gas in the exhaust port 12 is again sucked into the combustion chamber 11, whereby the pressure in the exhaust port 12 and in the branch portion of the exhaust manifold 7 becomes slightly lower than the atmospheric pressure. As is aforementioned, if both the intake valve and the exhaust valve 6 are in .. . . . . ... ... . . . .... . . . . .. ... . . . .. ..
-opened positions during the time when the piston has a position at round TDC, the pressure in the exhaust port 12 and in the branch portion of the exhaust manifold 7 ap-proaches that of a vacuum. According to the invention, the internal combustion engine is provided with an auto-matically opening and closing reed valve 13 known per se in order to feed a secondary air for promoting the oxidation of unburned gas into the exhaust port 12 by using said ; vacuum, or by using the fluctuations of the exhaust gas pressure, said fluctuations are created by the opening and closing operation of the exhaust valve 6 and the intake valve. The reed valve 13 is connected to the dust portion of the air cleaner at a position opposite to the air inlet opening in the air cleaner 9 via conduit 14, an air filter 15 for filtering the secondary air, a silencer 16 for stopping a suction noise of the secondary air and a conduit 17, on one hand; and to a predetermined number of exhaust ports 12, as will be hereinafter explained, via an air suction manifold 18, branch conduits 19, air suction nozzles 20 disposed on the front ends of the branch conduits ;1 19 and passages 21 formed in the cylinder head 4, on the other hand. The reed valve 13 opens when the pressure in the branch conduits 19 becomes slightly lower than that in the conduit 17, i.e., the atmospheric pressure, or when a decrease in the pressure greater than a predetermined value takes place in the branch conduits 19. Consequently, when the pressure in the exhaust port 12 becomes similar to that in a vacuum or when the pressure drop takes place in the exhaust port 12, air is sucked into the exhaust port 12 from the air cleaner 9 via the conduit 17, the .. . , .. . . .. . . .. ..... . .. .. ~ . . ... . . . . ~ . .. . ... . .
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silencer 16, the air filter 15, the conduit 14, the reed valve 13, the air suction manifold 18, the branch conduits 19, the air suction nozzles 20 and the passages 21.
An internal combustion engine used for an automobile, for example, is generally provided with four, six or eight cylinders. Of course, it is possible to provide the reed valves and the air filters for every cylinder, however, this causes an increase in costs and difficulties in construction. Furthermore, it has been found that, for example, in an internal combustion engine having four cylinders, if the secondary air is fed into the exhaust passages, i.e. the exhaust port 12 or the branch portion of the exhaust manifold 7 of only two of the four cylinders, ; it is possible to supply the exhaust gas with a sufficient amount of air which is needed for effectively promoting the oxidation in the catalytic converter. ~onsequently, consideration must be directed as to which exhaust passages among those of the four cylinders the secondary air should be fed into.
As is shown in Figs. 5 through 7, assuming that an internal combustion engine is provided with four cylinders comprised of No.l cylinder, No.2 cylinder, No.3 cylinder and No.4 cylinder, and the firing order in this engine is No.l-No.3-No.4-No.2, the exhaust- and intake-valve timing in each cylinder is as shown in Fig. 4. In Fig. 4, the abscissa indicates the crank angle eand the ordinate indicates the valve lift of the exhaust valve and the intake valve in each cylinder. Each of the A curves indicated by the hatched line shows the respective exhaust valve lifts in No.l through No.4 cylinders, and each of the B curves shows the respective intake valve lifts in No.l through No.4 cylinders. Furthermore, the duration of an overlap between the exhaust valve and the intake valve is shown by C.
It is assumed that branch conduits 19 which are connected to a single reed valve 13 having the air filter 13 are connected to No.l and No.2 cylinders, respectively.
In this case, it is apparent from Fig. 4 that when the intake valve and the exhaust valve of No.2 cylinder, are, in a durational phase of an overlap and thus the pressure in the exhaust port 12 of No.2 cylinder is similar to that in a vacuum, the exhaust valve A of No.l cylinder is in an opened position. Thus, the pressure in the exhaust port 12 of No.l cylinder is greater than the atmospheric pressure.
As a result, the reed valve 13 is closed by the action of the pressure created in the exhaust port of No.l cylinder.
Conse~uently, in spite of the creation of the vacuum and the occurrence of the pressure drop in the exhaust port of No.2 cylinder, the secondary air cannot be fed into the exhaust port of No.2 cylinder. That is to say, if the branch conduits 19 are connected to said two cylinders that, when the intake valve and the exhaust valve of one of the cylinders are in the durational phase of an overlap, then, the exhaust valve of the other cylinder is in an ; 25 opened position. In other words, when said two cylinders are subjected to a condition wherein the opening durations of the exhaust valves of both cylinders overlap with each other, a secondary air cannot be fed into one of the two cylinders under the influence of the other cylinder.
Consequently, in order to supply two cylinders with the secondary air, the branch conduits 19 must be connected to said two cylinders such that the opening durations of the exhaust valves of both cylinders do not overlap with each other. Furthermore, it is considerably effective in the operation of supplying the secondary air to divide an exhaust manifold into two separate exhaust manifolds, one ,~ of which is used for said two cylinders, the other exhaust manifold being used for the remaining cylinders.
Referring to Fig. 5 while taking into consideration the above, the posslble combinations of two cylinders ~! which should be connected to the single reed valve 13 are either the combination of No.l cylinder with No.4 cylinder ' as shown in Fig.5, or the combination of No.2 cylinder i! ' with No.3 cylinder as shown in Fig~ 6. In either case, as lS aforementioned, it is further effective to divide an exhaust manifold into two separate exhaust manifolds as shown in F.ig. 1 and as shown by the broken line in Fig. 6.
Although the engine construction lS made slightly com-plicated, in order to supply all of the cylinders with the I ~ 20 secondary air, as shown in Fig. 7, the engine may be ¦ provided with the branch conduits l9 connected to No.l cylinder-and No.4 cylinder, the reed valve 13 connected to the branch conduits 19, the branch conduits 19' connected to No.2 cylinder and No.3 cylinder, the reed valve 13' connected to the branch conduits 19' and the air filter 15 connected to the reed valves 13 and 13'.
Figs. 8 and 10 show another embodiment in the case of applying the present invention to a six-cylinder engine.
In Figs. 8 through 10, the description of the components is omitted because Fig. 8 is depicted in a similar manner as Fig. 4 and also Figs. 9 and 10 are depicted in a similar manner as Figs. 5 through 7. Referring to Fig. 8, in a six-cylinder engine, the possible combination of two cylinders which should be connected to the single reed valve 13 is, for example, the combination of No.l cylinder with No.6 cylinder, or the combination of No.2 cylinder with No.5 cylinder, or the combination of No.3 cylinder with No.4 cylinder as shown in Fig. 9. Furthermore, in a si~-cylinder engine, three cylinders such as No.l, No.2 and No.3 cylinders or No.4, No.5 and No.6 cylinders can be 1 combined and connected to the single reed valve 13. That , is to say, it is possible to combine said three cylinders in such a way that the crank angles of these three cylinders, , which cause the opening of the intake valves, are 240 apart from o~e another. In the case of combining the above-mentioned three cylinders, these three cylinders are affected much more by the remaining cylinders than would the two cylinders be affected by the remainlng cylinders in the case of combining two cylinders, crank angles for opening the intake valves of said two cylinders being 360 apart from each other. However, when it is sufficient to supply a small amount of a secondary air to the above-mentioned three cylinders connected to the single reed valve, the combination of three cylinders can be used. Of ~5 course, in Figs. 9 and 10, the engine is provided with a plurality of reed valves and with a single air filter as shown in Fig. 7, thereby feeding a secondary air into all of the cylinders. Fig. 11 shows the reed valve. The reed valve comprises a reed valve body 22, a valve seat 24 forming thereon a pair of valve ports 23 and a pair of ~67Q14 valves 25 normally closing the valve ports 23.
In the em~odiment shown in Fig. 1, the passage 21 connected to the branch conduit 19 opens into the exhaust port 12. However, the branch conduit 19 may directly open into the branch portion of the exhaust manifold 7.
As is described hereinbefore, according to the present invention, the exhaust gas purifier of an extremely simple construction ensures the feeding of a secondary air into the exhaust passages.
~ Furthermore, as shown in Figs. 5 and 6, if the exhaust gas delivered from the cylinder which is not connected to the reed valve 13 is recirculated into the intake air system 28, for example the intake manifold 8 via an exhaust recirculation control valve 26 for controlling the flow rate of the exhaust gas and an exhaust gas passage 27, said exhaust gas containing no air, that is to say, inert gas can be recirculated into the intake manifold, thereby bringing about an effective reduction of the harmful conponent NOX in the exhaust gas. Furthermore, if the duration of an overlap between the intake valve and the exhaust valve in each cylinder which is connected to the reed valve is extended compared with those durations in the remaining cylinders not connected to the reed valve, thereby increasing the feed amount of a secondary air into the former cylinders, it is then possible to improve the purifying efficiency and also improve the engine performance.
In addition, the atmospheric side of the reed valve 13 is connected to the dust portion of the air cleaner 9 at a position opposite to the air inlet opening in the air -- 11 -- .
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cleaner 9 via the air filter 15 and the silencer 16.
Thus, when the occurrence of a malfunctioning of the reed valve 13 causes the exhaust gas to flow reversely into the air cleaner via the branch conduit 19, the conduits 18 and 17, the exhaust gas must not be delivered to the atmosphere; and said gas can be sucked again into the ~, combustion chamber.
:. The present invention is hereinbefore described with a reference to the preferred embodiment in which the engine is.provided with a catalytic converter in its exhaust system. However, the catalytic converter can be replaced by a manifold reactor or an after-burner.
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in pressure below a predetermined value in the exhaust passages of the cylinders of said one cylinder group to permit the supply of an air into the exhaust passages of ; the cylinders of said one cylinder group.
The above-mentioned object of the invention may be more fully understood from the following description of a preferred embodiment of the invention and from the accom-panying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
Fig. 1 is a schematic plane view of an internal t combustion engine having the exhaust gas purifier according to the present invention;
Fig. 2 is a cross-sectional view taken along the line II-II in Fig. l;
Fig. 3 is a view showing intake- and exhaust-valve timing;
Fig. 4 is a view showing valve lifts of an intake valve and an exhaust valve of each cylinder in a four-cylinder engine;
Fig. 5 is a schematic plane view of an embodiment showing the possible combinations of the cylinders which the branch conduits should be connected to;
Fig. 6 is a view similar to Fig. 5, showing j 25 another embodiment;
Fig. 7 is a view similar to Fig. 5, showing the other embodiment;
Fig. 8 is a view showing valve lifts of an intake valve and an exhaust valve of each cylinder in a six-cylinder engine;
. - 3 -10670~4 Fig. 9 is a schematic plane view of an embodiment showing the various possible combinations of cylinders which the branch conduits should be connected to;
Fig. 10 is a view similar to Fig. 9, showing another embodiment, and;
Fig. 11 is a pxospective view of the reed valve.
DESCRIPTION OF A PREFERRED EMBODIMENT
Fig. 1 shows a schematic plane view of the internal combustion engine having the exhaust gas purifier according to the present invention and Fig. 2 shows a cross-sectional view of a part of the engine shown in Fig. 1.
Referring to Figs. 1 and 2, the internal combustion engine comprises a cylinder block 1, a piston 3 reciprocatively movable in the cylinder 2 formed in the cylinder block 1, a cylinder head 4 fixed onto the cylinaer block 1, an intake valve (not shown), an exhaust valve 6 for controlling the opening and closing operation of an exhaust port 5, an exhaust manifold 7 and an intake manifold 8 which are fixed onto the cylinder head 4, an air cleaner 9 mounted on the intake manifold 8 and a catalytic converter 10.
-The gas to be exhausted which has been burned in a combustion ; chamber 11 is delivered into the catalytic converter 10 through the exhaust manifold 7, and then, the gas cleaned in the catalytic converter 10 is delivered to the atmosphere.
Fig. 3 shows the intake- and exhaust-valve timing.
In a conventional internal combustion engine having the intake valve and the exhaust valve, a duration of overlap between the intake valve and the exhaust valve occurs during which both the intake and the exhaust valves are each in an opened position immediately before the exhaust .. . , . . . . . .. ~ ... .
,1 .
valve is closed. As in shown in Fig. 3, for example, the exhaust valve A opens 50 before BDC (Bottom dead center) and closes 16D after TDC (Top dead center), and the intake valve B opens 16 before TDC and closes 50 after BDC.
Consequently, as is shown by arrow C, a duration of overlap occurs when both exhaust valve A and the intake valve B
are each in an opened position.
In Fig. 2, assuming that the engine is in an exhaust stroke position during which the exhaust valve 6 is in an opened position, tha gas to be exhausted in the combustion chamber 11 is delivered into the catalytic converter 10 ' via the exhaust valve port 5, the exhaust port 12 and the exhaust manifold 7 as the piston 3 is moved upwords in the ; cylinder 2. At this time, the pressure in the exhaust - lS port 12 and in the branch portion of the exhaust manifold 7 is greater than the atmospheric pressure. Then, when the intake valve opens and piston 3 is further moved upwards so as to reach its uppermost position (TDC), the pressure in the exhaust port 12 and in the branch portion of the exhaust manifold 7 becomes substantially the same as the atmospheric pressure. Then, when the piston 3 begins to move downwards, the fuel mixture is sucked into the combustion chamber 11 via the intake port (not shown).
At this time, the exhaust valve 6 is still in an opened ; 25 position. Thus, a part of the exhaust gas in the exhaust port 12 is again sucked into the combustion chamber 11, whereby the pressure in the exhaust port 12 and in the branch portion of the exhaust manifold 7 becomes slightly lower than the atmospheric pressure. As is aforementioned, if both the intake valve and the exhaust valve 6 are in .. . . . . ... ... . . . .... . . . . .. ... . . . .. ..
-opened positions during the time when the piston has a position at round TDC, the pressure in the exhaust port 12 and in the branch portion of the exhaust manifold 7 ap-proaches that of a vacuum. According to the invention, the internal combustion engine is provided with an auto-matically opening and closing reed valve 13 known per se in order to feed a secondary air for promoting the oxidation of unburned gas into the exhaust port 12 by using said ; vacuum, or by using the fluctuations of the exhaust gas pressure, said fluctuations are created by the opening and closing operation of the exhaust valve 6 and the intake valve. The reed valve 13 is connected to the dust portion of the air cleaner at a position opposite to the air inlet opening in the air cleaner 9 via conduit 14, an air filter 15 for filtering the secondary air, a silencer 16 for stopping a suction noise of the secondary air and a conduit 17, on one hand; and to a predetermined number of exhaust ports 12, as will be hereinafter explained, via an air suction manifold 18, branch conduits 19, air suction nozzles 20 disposed on the front ends of the branch conduits ;1 19 and passages 21 formed in the cylinder head 4, on the other hand. The reed valve 13 opens when the pressure in the branch conduits 19 becomes slightly lower than that in the conduit 17, i.e., the atmospheric pressure, or when a decrease in the pressure greater than a predetermined value takes place in the branch conduits 19. Consequently, when the pressure in the exhaust port 12 becomes similar to that in a vacuum or when the pressure drop takes place in the exhaust port 12, air is sucked into the exhaust port 12 from the air cleaner 9 via the conduit 17, the .. . , .. . . .. . . .. ..... . .. .. ~ . . ... . . . . ~ . .. . ... . .
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silencer 16, the air filter 15, the conduit 14, the reed valve 13, the air suction manifold 18, the branch conduits 19, the air suction nozzles 20 and the passages 21.
An internal combustion engine used for an automobile, for example, is generally provided with four, six or eight cylinders. Of course, it is possible to provide the reed valves and the air filters for every cylinder, however, this causes an increase in costs and difficulties in construction. Furthermore, it has been found that, for example, in an internal combustion engine having four cylinders, if the secondary air is fed into the exhaust passages, i.e. the exhaust port 12 or the branch portion of the exhaust manifold 7 of only two of the four cylinders, ; it is possible to supply the exhaust gas with a sufficient amount of air which is needed for effectively promoting the oxidation in the catalytic converter. ~onsequently, consideration must be directed as to which exhaust passages among those of the four cylinders the secondary air should be fed into.
As is shown in Figs. 5 through 7, assuming that an internal combustion engine is provided with four cylinders comprised of No.l cylinder, No.2 cylinder, No.3 cylinder and No.4 cylinder, and the firing order in this engine is No.l-No.3-No.4-No.2, the exhaust- and intake-valve timing in each cylinder is as shown in Fig. 4. In Fig. 4, the abscissa indicates the crank angle eand the ordinate indicates the valve lift of the exhaust valve and the intake valve in each cylinder. Each of the A curves indicated by the hatched line shows the respective exhaust valve lifts in No.l through No.4 cylinders, and each of the B curves shows the respective intake valve lifts in No.l through No.4 cylinders. Furthermore, the duration of an overlap between the exhaust valve and the intake valve is shown by C.
It is assumed that branch conduits 19 which are connected to a single reed valve 13 having the air filter 13 are connected to No.l and No.2 cylinders, respectively.
In this case, it is apparent from Fig. 4 that when the intake valve and the exhaust valve of No.2 cylinder, are, in a durational phase of an overlap and thus the pressure in the exhaust port 12 of No.2 cylinder is similar to that in a vacuum, the exhaust valve A of No.l cylinder is in an opened position. Thus, the pressure in the exhaust port 12 of No.l cylinder is greater than the atmospheric pressure.
As a result, the reed valve 13 is closed by the action of the pressure created in the exhaust port of No.l cylinder.
Conse~uently, in spite of the creation of the vacuum and the occurrence of the pressure drop in the exhaust port of No.2 cylinder, the secondary air cannot be fed into the exhaust port of No.2 cylinder. That is to say, if the branch conduits 19 are connected to said two cylinders that, when the intake valve and the exhaust valve of one of the cylinders are in the durational phase of an overlap, then, the exhaust valve of the other cylinder is in an ; 25 opened position. In other words, when said two cylinders are subjected to a condition wherein the opening durations of the exhaust valves of both cylinders overlap with each other, a secondary air cannot be fed into one of the two cylinders under the influence of the other cylinder.
Consequently, in order to supply two cylinders with the secondary air, the branch conduits 19 must be connected to said two cylinders such that the opening durations of the exhaust valves of both cylinders do not overlap with each other. Furthermore, it is considerably effective in the operation of supplying the secondary air to divide an exhaust manifold into two separate exhaust manifolds, one ,~ of which is used for said two cylinders, the other exhaust manifold being used for the remaining cylinders.
Referring to Fig. 5 while taking into consideration the above, the posslble combinations of two cylinders ~! which should be connected to the single reed valve 13 are either the combination of No.l cylinder with No.4 cylinder ' as shown in Fig.5, or the combination of No.2 cylinder i! ' with No.3 cylinder as shown in Fig~ 6. In either case, as lS aforementioned, it is further effective to divide an exhaust manifold into two separate exhaust manifolds as shown in F.ig. 1 and as shown by the broken line in Fig. 6.
Although the engine construction lS made slightly com-plicated, in order to supply all of the cylinders with the I ~ 20 secondary air, as shown in Fig. 7, the engine may be ¦ provided with the branch conduits l9 connected to No.l cylinder-and No.4 cylinder, the reed valve 13 connected to the branch conduits 19, the branch conduits 19' connected to No.2 cylinder and No.3 cylinder, the reed valve 13' connected to the branch conduits 19' and the air filter 15 connected to the reed valves 13 and 13'.
Figs. 8 and 10 show another embodiment in the case of applying the present invention to a six-cylinder engine.
In Figs. 8 through 10, the description of the components is omitted because Fig. 8 is depicted in a similar manner as Fig. 4 and also Figs. 9 and 10 are depicted in a similar manner as Figs. 5 through 7. Referring to Fig. 8, in a six-cylinder engine, the possible combination of two cylinders which should be connected to the single reed valve 13 is, for example, the combination of No.l cylinder with No.6 cylinder, or the combination of No.2 cylinder with No.5 cylinder, or the combination of No.3 cylinder with No.4 cylinder as shown in Fig. 9. Furthermore, in a si~-cylinder engine, three cylinders such as No.l, No.2 and No.3 cylinders or No.4, No.5 and No.6 cylinders can be 1 combined and connected to the single reed valve 13. That , is to say, it is possible to combine said three cylinders in such a way that the crank angles of these three cylinders, , which cause the opening of the intake valves, are 240 apart from o~e another. In the case of combining the above-mentioned three cylinders, these three cylinders are affected much more by the remaining cylinders than would the two cylinders be affected by the remainlng cylinders in the case of combining two cylinders, crank angles for opening the intake valves of said two cylinders being 360 apart from each other. However, when it is sufficient to supply a small amount of a secondary air to the above-mentioned three cylinders connected to the single reed valve, the combination of three cylinders can be used. Of ~5 course, in Figs. 9 and 10, the engine is provided with a plurality of reed valves and with a single air filter as shown in Fig. 7, thereby feeding a secondary air into all of the cylinders. Fig. 11 shows the reed valve. The reed valve comprises a reed valve body 22, a valve seat 24 forming thereon a pair of valve ports 23 and a pair of ~67Q14 valves 25 normally closing the valve ports 23.
In the em~odiment shown in Fig. 1, the passage 21 connected to the branch conduit 19 opens into the exhaust port 12. However, the branch conduit 19 may directly open into the branch portion of the exhaust manifold 7.
As is described hereinbefore, according to the present invention, the exhaust gas purifier of an extremely simple construction ensures the feeding of a secondary air into the exhaust passages.
~ Furthermore, as shown in Figs. 5 and 6, if the exhaust gas delivered from the cylinder which is not connected to the reed valve 13 is recirculated into the intake air system 28, for example the intake manifold 8 via an exhaust recirculation control valve 26 for controlling the flow rate of the exhaust gas and an exhaust gas passage 27, said exhaust gas containing no air, that is to say, inert gas can be recirculated into the intake manifold, thereby bringing about an effective reduction of the harmful conponent NOX in the exhaust gas. Furthermore, if the duration of an overlap between the intake valve and the exhaust valve in each cylinder which is connected to the reed valve is extended compared with those durations in the remaining cylinders not connected to the reed valve, thereby increasing the feed amount of a secondary air into the former cylinders, it is then possible to improve the purifying efficiency and also improve the engine performance.
In addition, the atmospheric side of the reed valve 13 is connected to the dust portion of the air cleaner 9 at a position opposite to the air inlet opening in the air -- 11 -- .
~ 067014 ;
cleaner 9 via the air filter 15 and the silencer 16.
Thus, when the occurrence of a malfunctioning of the reed valve 13 causes the exhaust gas to flow reversely into the air cleaner via the branch conduit 19, the conduits 18 and 17, the exhaust gas must not be delivered to the atmosphere; and said gas can be sucked again into the ~, combustion chamber.
:. The present invention is hereinbefore described with a reference to the preferred embodiment in which the engine is.provided with a catalytic converter in its exhaust system. However, the catalytic converter can be replaced by a manifold reactor or an after-burner.
..
. - 12 -:
Claims (10)
1. An improved exhaust gas purifier in a four-stroke internal combustion engine having a plurality of cylinders each having an intake valve, an exhaust valve and an exhaust passage said cylinders being arranged in first and second cylinder groups, said first cylinder group comprising at least two cylinders, of which the opening durations of the exhaust valves do not overlap, wherein the improvement comprises:
an exhaust pipe, an intake manifold, first and second independent and separate exhaust manifolds joined at the downstream end to said exhaust pipe, said first cylinder group being connected to said first exhaust manifold and said second cylinder group to said second exhaust manifold, an exhaust gas conduit connecting said second exhaust manifold to said intake manifold, an air passage for connecting the exhaust passages of the cylinders of said first group with the atmosphere, and a valve means disposed in said air passage and arranged to open automatically in response to a decrease in pressure below a predetermined value in the exhaust passages of the cylinders of said first cylinder group to permit a supply of air from the atmosphere into the exhaust passages of only the cylinders of said first cylinder group and not said second cylinder group.
an exhaust pipe, an intake manifold, first and second independent and separate exhaust manifolds joined at the downstream end to said exhaust pipe, said first cylinder group being connected to said first exhaust manifold and said second cylinder group to said second exhaust manifold, an exhaust gas conduit connecting said second exhaust manifold to said intake manifold, an air passage for connecting the exhaust passages of the cylinders of said first group with the atmosphere, and a valve means disposed in said air passage and arranged to open automatically in response to a decrease in pressure below a predetermined value in the exhaust passages of the cylinders of said first cylinder group to permit a supply of air from the atmosphere into the exhaust passages of only the cylinders of said first cylinder group and not said second cylinder group.
2. An improved exhaust gas purifier as recited in claim 1, wherein said valve means is a reed valve.
3. An improved exhaust gas purifier as recited in claim 1 including an air cleaner having an air inlet opening and an outlet, wherein said air passage extends from said outlet of said air cleaner to said valve means and to the exhaust passages of the cylinders of said one cylinder group, said outlet of said air cleaner being at a position opposite to the inlet opening thereof.
4. An improved exhaust gas purifier as recited in claim 3, wherein an air filter is disposed between the valve means and the air cleaner.
5. An improved exhaust gas purifier as recited in claim 3, wherein a silencer and an air filter are disposed between the valve means and the air cleaner.
6. An improved exhaust gas purifier as recited in claim 1, wherein said second exhaust manifold is connected to an intake manifold of the engine via an exhaust recirculation control valve.
7. An exhaust gas purifier as claimed in claim 1 or 2, wherein the durations of the overlap of the intake valves with the exhaust valves in said first cylinder group are longer than those in said second cylinder group.
8. An exhaust gas purifier as claimed in claim 1 where-in said purifier further comprises a catalytic converter in the exhaust passage of the engine.
9. An exhaust gas purifier as claimed in claim 1 where-in said purifier further comprises a manifold reactor in the exhaust passage of the engine.
10. An exhaust gas purifier as recited in claim 1 wherein said purifier further comprises a thermal reactor in the exhaust passage of the engine.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CA320,993A CA1068217A (en) | 1975-12-26 | 1979-02-05 | Exhaust gas purifier of an internal combustion engine |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP50154848A JPS5279120A (en) | 1975-12-26 | 1975-12-26 | Exhaust gas purifier for internal combustion engine |
Publications (1)
Publication Number | Publication Date |
---|---|
CA1067014A true CA1067014A (en) | 1979-11-27 |
Family
ID=15593210
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA249,761A Expired CA1067014A (en) | 1975-12-26 | 1976-04-07 | Exhaust gas purifier of an internal combustion engine |
Country Status (3)
Country | Link |
---|---|
JP (1) | JPS5279120A (en) |
CA (1) | CA1067014A (en) |
DE (1) | DE2617245C2 (en) |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5344732A (en) * | 1976-10-04 | 1978-04-21 | Mazda Motor Corp | Exhaust gas purifier for engine |
JPS5540338Y2 (en) * | 1977-02-25 | 1980-09-20 | ||
JPS5423817A (en) * | 1977-07-22 | 1979-02-22 | Toyota Motor Corp | Internal combustion engine exhaust purifier |
JPS6038531B2 (en) * | 1978-06-16 | 1985-09-02 | 日産自動車株式会社 | Secondary air introduction device |
DE102006018200A1 (en) | 2006-04-19 | 2007-10-25 | Volkswagen Ag | Internal combustion engine, has secondary air pump provided for supply of secondary air to exhaust gas and connected with few exhaust gas flows by secondary air valve, where remaining gas flows are separated from pump and valve |
JP6217678B2 (en) * | 2015-03-25 | 2017-10-25 | トヨタ自動車株式会社 | cylinder head |
DE102020127506B4 (en) | 2020-10-19 | 2023-11-02 | Pierburg Gmbh | Internal combustion engine |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3500807A (en) * | 1968-03-04 | 1970-03-17 | Atlantic Richfield Co | Exhaust recycle system |
GB1244808A (en) * | 1968-07-10 | 1971-09-02 | Nissan Motor | Internal combustion engine exhaust gas oxidizing system |
GB1305996A (en) * | 1969-05-30 | 1973-02-07 | ||
GB1368286A (en) * | 1970-09-22 | 1974-09-25 | Alfa Romeo Spa | Exhaust system for internal combustion engines |
JPS5653049Y2 (en) * | 1974-05-30 | 1981-12-10 |
-
1975
- 1975-12-26 JP JP50154848A patent/JPS5279120A/en active Granted
-
1976
- 1976-04-07 CA CA249,761A patent/CA1067014A/en not_active Expired
- 1976-04-20 DE DE2617245A patent/DE2617245C2/en not_active Expired
Also Published As
Publication number | Publication date |
---|---|
DE2617245A1 (en) | 1977-07-07 |
JPS5279120A (en) | 1977-07-04 |
DE2617245C2 (en) | 1984-02-23 |
JPS539665B2 (en) | 1978-04-07 |
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