US3885537A - Road load modulated exhaust gas recirculation system - Google Patents

Road load modulated exhaust gas recirculation system Download PDF

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Publication number
US3885537A
US3885537A US413159A US41315973A US3885537A US 3885537 A US3885537 A US 3885537A US 413159 A US413159 A US 413159A US 41315973 A US41315973 A US 41315973A US 3885537 A US3885537 A US 3885537A
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United States
Prior art keywords
egr
vacuum
valve
air
port
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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 - Lifetime
Application number
US413159A
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English (en)
Inventor
Roy E Diehl
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ford Motor Co
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Ford Motor Co
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Filing date
Publication date
Application filed by Ford Motor Co filed Critical Ford Motor Co
Priority to US413159A priority Critical patent/US3885537A/en
Priority to AU73969/74A priority patent/AU477743B2/en
Priority to CA211,398A priority patent/CA1020827A/en
Priority to GB4620074A priority patent/GB1445933A/en
Priority to DE2451148A priority patent/DE2451148C3/de
Priority to JP12667774A priority patent/JPS5411852B2/ja
Application granted granted Critical
Publication of US3885537A publication Critical patent/US3885537A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/52—Systems for actuating EGR valves
    • F02M26/55—Systems for actuating EGR valves using vacuum actuators
    • F02M26/56—Systems for actuating EGR valves using vacuum actuators having pressure modulation valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M26/00—Engine-pertinent apparatus for adding exhaust gases to combustion-air, main fuel or fuel-air mixture, e.g. by exhaust gas recirculation [EGR] systems
    • F02M26/13—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
    • F02M26/17—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories in relation to the intake system
    • F02M26/21—Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories in relation to the intake system with EGR valves located at or near the connection to the intake system

Definitions

  • ABSTRACT The carburetor has an exhaust gas recirculation vac- 22 Filed: Nov. 5, 1973 [21] App]. No.: 413,159
  • uum port located above the closed position of the throttle valve, the vacuum providing a signal to an EGR valve to open it upon the attainment of a prede- [52] U.S. 123/119 A termined vacuum level to pass exhaust gases into the engine intake manifold, the vacuum line containing a [58] Field of pair of flow restrictors and an air bleed device to at times bleed air into the vacuum line to cause the EGR valve to schedule EGR flow at. a rate proportional to load during part throttle operations [56] References Cited UNITED STATES PATENTS 3,783,847 1/1974 Kolody............................123/119A 3D 3,796,049 3/1974 Hayashi].
  • This invention relates, in general, to an internal combustion engine. More particularly, it relates to a system for controlling the recirculation of exhaust gases back into the engine through the intake manifold.
  • Devices for recirculating a portion of the exhaust gases to control the emission of unburned hydrocarbons and lower the output of oxides of nitrogen. These devices have included valving to prevent recirculation of the exhaust gases at undesired times and generally are controlled by movement of the carburetor throttle valve to prevent recirculation during engine idle and wide-open throttle operations. This is desirable because at engine idle, exhaust gas scavenging is inefficient, while at wide-open throttle position, maximum power is limited by the availability of oxygen.
  • EGR exhaust gas recirculation
  • EGR port the level of manifold vacuum in a port traversed by the carburetor throttle valve
  • Another object of the invention is to improve engine drivability by reducing exhaust gas recirculation during light engine loads when the recirculation required to control NO, output, for example, generally is less than that which is usually scheduled.
  • FIG. 1 is a cross-sectional view of a portion of an internal combustion engine and associated carburetor embodying the invention
  • FIG. 2 is a cross-sectional view taken on a plane indicated by and viewed in the direction of the arrows 2-2 of FIG. 1;
  • FIG. 3 is a schematic illustration of the control portion of the invention.
  • FIG. 1 illustrates a portion of one-half of a twobarrel carburetor of a known downdraft type. It has an air horn section 12, a main body portion 14, and a throttle body 16, joined by suitable means not shown.
  • the carburetor has the usual air/fuel induction passage 18 open at their upper ends 20 to fresh air from the conventional air cleaner, not shown.
  • the passages 18 have the usual fixed area venturies 22 cooperating with booster venturies 24 through which the main supply of fuel is induced,.by means not shown.
  • Flow of air and fuel through induction passages 18 is controlled by a pair of throttle valve plates 26 each fixed on a shaft 28 rotatably mounted in the side walls of the carburetor body.
  • the throttle body 16 is flanged as indicated for bolt ing to the top of the engine intake manifold 30, with a spacer element 32 located between.
  • Manifold 30 has a number of vertical risers or bores 34 that are aligned for cooperation with the discharge end of the carburetor induction passages 18.
  • the risers 34 extend at right angles at their lower ends 36 for passage of the mixture out of the plane of the figure to the intake valves of the engine.
  • the exhaust manifolding part of the engine cylinder head is indicated partially at 38, and includes an exhaust gas crossover passage 40.
  • the latter passes from the exhaust manifold, not shown, on one side of the engine to the opposite side beneath the manifold trunks 36 to provide the usual hot spot beneath the carburetor to better vaporize the air/fuel mixture.
  • the spacer 32 is provided with a worm-like recess 42 that is connected directly to crossover passage 40 by a bore 44. Also connected to passage 42 is a passage 46 alternately blocked or connected to a central bore or passage 48 communicating with the risers 34 through a pair of ports 50. Mounted to one side of the spacer is a cup shaped boss 52 forming a chamber 54 through which passages 46 and 48 are interconnected.
  • passage 46 normally is closed by a valve 56 that is moved to an open position by a servo 58.
  • the servo includes a hollow outer shell 64 containing an annular flexible diaphragm 66. The latter divides the interior into an air chamber 68 and a signal vacuum chamber 70. Chamber 68 is connected to atmospheric pressure through a vent 72, while chamber 70 is connected to a vacuum signal forcethrough a line 74.
  • the stem of valve 56 is fixed to a pair of retainers 76 secured to diaphragm 66. They serve as a seat for a compression spring 77 normally biasing the valve to its closed position.
  • the stem slidably and sealingly projects through a plate 78 closing chamger 54.
  • the carburetor contains an exhaust gas recirculating (EGR) port 80 that is located above the closed position of throttle valve 26, to be traversed by the edge of the throttle valve as it moves open.
  • EGR exhaust gas recirculating
  • the pressure in port 80 thereby varies from atmospheric to the manifold vacuum level as a function of the opening of throttle valve 28.
  • Port 80 is connected to a passage 86.
  • Passage 86 is connected to servo vacuum line 74 through apparatus that at times lowers the vacuum signal to a different value at the servo than exists at port 80, for a purpose to be described. More specifically, line 86 contains a pair of fixed area orifices or flow restricting devices 90 and 92 interconnected by a passage 94. The line 74 is connected to passage 94.
  • a manifold vacuum controlled air bleed device 84 Downstream of orifice 92 is a manifold vacuum controlled air bleed device 84. It has an outer housing 98 divided into two chambers 1(l 0 and 102 by an annular flexible diaphragm 104. The lower shell portion is formed with two passages 106 and 108. Passage 108 is formed at its chamber end with a conical seat 110 cooperating with the diaphragm 104 acting as a valve seat and valve combination, respectively.
  • a compression spring 112 is seated between a spacer 1 l4 riveted to the diaphragm and an adjustable stop 116. Adjusting the stop will change the spring preload to a desired level.
  • the air bleed device controls the bleed of air into EGR vacuum line 94 as a function of manifold vacuum level.
  • Chamber 100 is connected by a passage 118 to a manifold vacuum port 120 located below the closed position of throttle valve 28.
  • Lower passage 106 is vented to atmosphere, while passage 108 is connected to the downstream side of the flow restrictor 92. If the force of spring 112 is chosen, for example, to be such as to keep diaphragm 104 against seat 110 until the manifold vacuum rises above 7 inches Hg., then the diaphragm will block off the bleed of air into passage 108 for all vacuum levels below 7 inches Hg.
  • the vacuum level in line 74 is reduced proportional to the size of the restrictors or orifices 90 and 92, the size of which can be a matter of choice to provide the desired vacuum level schedule. For example, if the orifices are of equal size, then the vacuum signal force in line 74 will be one-half of the true value at the EGR port 80. If orifice 90 has a flow area of two times that of orifice 92, then the vacuum signal force in line 74 will be about two-thirds that of the EGR port vacuum level.
  • a branch line 122 containing a one-way check valve 124, bypasses the orifice 90 to allow full flow of the then higher pressure at the EGR port in line 86 to line 74. This is desired so the EGR valve will close quickly during decelerations, for example.
  • the invention is used to reduce the EGR servo vacuum signal to a level below that at the carburetor EGR port 80, at particular modes of engine operation. This improves drivability while maintaining a given NO emission level since the volume of EGR flow called for by the EGR port vacuum level during cruising or light load operations generally is in excess of that actually needed to maintain a low NO, level. Conversely, when the signal is at full value, the NO emissions will be lowered while maintaining a given drivability.
  • the bleed valve device will remain open, bleeding air into passage 108 and through orifice 92 to the passage 74.
  • the EGR vacuum in port will be a mod ulated manifold vacuum as the throttle valve traverses the EGR port.
  • the bleed device will decay the EGR vacuum signal force to the EGR valve 56, thus providing only a small amount of EGR flow and one corresponding essentially to the light load operation.
  • the one-way check valve opens when the pressure at EGR port 80 goes to atmosphere, or when it becomes greater than the vacuum downstream of the check valve plus the force of the spring closing the check valve, if a spring is used. This is desirable to provide a fast closing of the EGR valve at this time because there is no need for EGR to reduce NO During decelerations, the engine is not producing horsepower and therefore is not producing N0 The air-fuel mixture is already excessively lean during decelerations; therefore, adding EGR would only further hinder its burning.
  • the invention provides an EGR flow rate during part load operations that is nearly proportional to engine load so that during maximum accelerations a maximum flow capacity is obtained, whereas during light load operation, only little flow is provided. Likewise, it will be seen that the invention prevents large flow when wide open throttle conditions of operation occur because at that time the EGR port vacuum is nearly zero.
  • An exhaust gas recirculating system for an internal combustion engine having a throttle valve controlling flow through a carburetor induction passage, comprising, a duct connecting the exhaust gases to the engine intake manifold, a spring closed exhaust gas recirculation (EGR) valve normally closing the duct to prevent recirculation and movable to an open position by a signal vacuum connected thereto, the induction passage containing an exhaust gas recirculating (EGR) port lo cated relative to the throttle valve so as to be at essentially atmospheric pressure at closed throttle positions with decreases in pressure level in proportion to the progressive opening of the throttle valve until EGR port vacuum reaches the level of manifold vacuum, conduit means operatively connecting the EGR port signal vacuum to the valve to move the same, and vacuum signal control means in the conduit means for at times reducing the EGR flow by reducing the level of the EGR vacuum signal at the EGR valve to a value below the value.at the EGR vacuum port, and below the level necessary to maintain the EGR valve open, the control means including an air bleed means responsive
  • the air bleed means including an atmospheric air passage, a flexible diaphragm type vacuum valve having spring means biasing the dia' phragm against the air passage closing the same, and means applying engine manifold vacuum to the diaphragm to move the vacuum valve above a predetermined manifold vacuum level to open the air passage and bleed down the EGR vacuum.
  • bleed means comprising an air source, second conduit means connecting the air source to the first mentioned conduit means, a spring closed air bleed valve normally blocking the second conduit means, a vacuum servo operably connected to the air bleed valve and movable in response to the attainment of a predetermined manifold vacuum to open the valve and bleed air into the conduit means.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust-Gas Circulating Devices (AREA)
US413159A 1973-11-05 1973-11-05 Road load modulated exhaust gas recirculation system Expired - Lifetime US3885537A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US413159A US3885537A (en) 1973-11-05 1973-11-05 Road load modulated exhaust gas recirculation system
AU73969/74A AU477743B2 (en) 1973-11-05 1974-10-03 Road load modulated exhaust gas recirculation system
CA211,398A CA1020827A (en) 1973-11-05 1974-10-15 Road load modulated exhaust gas recirculation system
GB4620074A GB1445933A (en) 1973-11-05 1974-10-25 Exhaust gas recirculation system
DE2451148A DE2451148C3 (de) 1973-11-05 1974-10-28 Abgasrückführeinrichtung bei Verbrennungsmotoren
JP12667774A JPS5411852B2 (de) 1973-11-05 1974-11-05

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US413159A US3885537A (en) 1973-11-05 1973-11-05 Road load modulated exhaust gas recirculation system

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US3885537A true US3885537A (en) 1975-05-27

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US413159A Expired - Lifetime US3885537A (en) 1973-11-05 1973-11-05 Road load modulated exhaust gas recirculation system

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US (1) US3885537A (de)
JP (1) JPS5411852B2 (de)
CA (1) CA1020827A (de)
DE (1) DE2451148C3 (de)
GB (1) GB1445933A (de)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4002154A (en) * 1975-02-06 1977-01-11 Dana Corporation Vacuum delay and shutoff valve
US4041915A (en) * 1975-01-14 1977-08-16 Nissan Motor Company Limited Apparatus to control the recirculation of exhaust gases into the intake passage in an internal combustion engine
US4106452A (en) * 1976-03-11 1978-08-15 Toyota Jidosha Kogyo Kabushiki Kaisha Exhaust gas recirculator
US4111172A (en) * 1974-11-30 1978-09-05 Nissan Motor Company, Limited System to feed exhaust gas into the induction passage of an internal combustion engine
US4267809A (en) * 1978-07-05 1981-05-19 Nissan Motor Company, Limited Exhaust gas recirculation control system

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS521233A (en) * 1975-06-23 1977-01-07 Toyota Motor Corp Exhaust gas recirculation device control system
JPS543221Y2 (de) * 1976-10-28 1979-02-14
JPS53136414U (de) * 1977-04-04 1978-10-28

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3783847A (en) * 1972-12-06 1974-01-08 Ford Motor Co Engine spark control and exhaust gas recirculation vacuum signal selector
US3796049A (en) * 1971-12-25 1974-03-12 Nissan Motor Exhaust gas recirculation system for an internal combustion engine

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2154417A (en) * 1937-11-06 1939-04-18 Harold D Church Fuel control for internal combustion engines
FR2088638A5 (de) * 1970-04-20 1972-01-07 Brev Etudes Sibe
US3884200A (en) * 1971-08-03 1975-05-20 Ranco Inc Exhaust gas recirculation control system for internal combustion engines
US3768452A (en) * 1972-04-04 1973-10-30 Ford Motor Co Engine exhaust gas recirculating control
JPS5065726A (de) * 1973-10-16 1975-06-03

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3796049A (en) * 1971-12-25 1974-03-12 Nissan Motor Exhaust gas recirculation system for an internal combustion engine
US3783847A (en) * 1972-12-06 1974-01-08 Ford Motor Co Engine spark control and exhaust gas recirculation vacuum signal selector

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4111172A (en) * 1974-11-30 1978-09-05 Nissan Motor Company, Limited System to feed exhaust gas into the induction passage of an internal combustion engine
US4041915A (en) * 1975-01-14 1977-08-16 Nissan Motor Company Limited Apparatus to control the recirculation of exhaust gases into the intake passage in an internal combustion engine
US4002154A (en) * 1975-02-06 1977-01-11 Dana Corporation Vacuum delay and shutoff valve
US4106452A (en) * 1976-03-11 1978-08-15 Toyota Jidosha Kogyo Kabushiki Kaisha Exhaust gas recirculator
US4267809A (en) * 1978-07-05 1981-05-19 Nissan Motor Company, Limited Exhaust gas recirculation control system

Also Published As

Publication number Publication date
JPS5411852B2 (de) 1979-05-18
JPS5074025A (de) 1975-06-18
AU7396974A (en) 1976-04-08
DE2451148B2 (de) 1981-01-08
DE2451148A1 (de) 1975-05-07
DE2451148C3 (de) 1981-10-08
CA1020827A (en) 1977-11-15
GB1445933A (en) 1976-08-11

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