WO2008056240A2 - Intake manifold for multi-cylinder engine - Google Patents

Intake manifold for multi-cylinder engine Download PDF

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Publication number
WO2008056240A2
WO2008056240A2 PCT/IB2007/003410 IB2007003410W WO2008056240A2 WO 2008056240 A2 WO2008056240 A2 WO 2008056240A2 IB 2007003410 W IB2007003410 W IB 2007003410W WO 2008056240 A2 WO2008056240 A2 WO 2008056240A2
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WO
WIPO (PCT)
Prior art keywords
cylinder
manifold
intake
surge tank
partition
Prior art date
Application number
PCT/IB2007/003410
Other languages
French (fr)
Other versions
WO2008056240A3 (en
Inventor
Yoichi Kobori
Naoki Osumi
Original Assignee
Toyota Jidosha Kabushiki Kaisha
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Toyota Jidosha Kabushiki Kaisha filed Critical Toyota Jidosha Kabushiki Kaisha
Publication of WO2008056240A2 publication Critical patent/WO2008056240A2/en
Publication of WO2008056240A3 publication Critical patent/WO2008056240A3/en

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Classifications

    • 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
    • F02M35/00—Combustion-air cleaners, air intakes, intake silencers, or induction systems specially adapted for, or arranged on, internal-combustion engines
    • F02M35/10—Air intakes; Induction systems
    • F02M35/104—Intake manifolds
    • F02M35/112—Intake manifolds for engines with cylinders all in one line
    • 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
    • F02B27/00—Use of kinetic or wave energy of charge in induction systems, or of combustion residues in exhaust systems, for improving quantity of charge or for increasing removal of combustion residues
    • F02B27/005—Oscillating pipes with charging achieved by arrangement, dimensions or shapes of intakes pipes or chambers; Ram air pipes
    • 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
    • F02M35/00—Combustion-air cleaners, air intakes, intake silencers, or induction systems specially adapted for, or arranged on, internal-combustion engines
    • F02M35/10—Air intakes; Induction systems
    • F02M35/10006—Air intakes; Induction systems characterised by the position of elements of the air intake system in direction of the air intake flow, i.e. between ambient air inlet and supply to the combustion chamber
    • F02M35/10026—Plenum chambers
    • F02M35/10045—Multiple plenum chambers; Plenum chambers having inner separation walls
    • 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
    • F02M35/00—Combustion-air cleaners, air intakes, intake silencers, or induction systems specially adapted for, or arranged on, internal-combustion engines
    • F02M35/10—Air intakes; Induction systems
    • F02M35/10006—Air intakes; Induction systems characterised by the position of elements of the air intake system in direction of the air intake flow, i.e. between ambient air inlet and supply to the combustion chamber
    • F02M35/10026—Plenum chambers
    • F02M35/10052—Plenum chambers special shapes or arrangements of plenum chambers; Constructional details
    • 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
    • F02M35/00—Combustion-air cleaners, air intakes, intake silencers, or induction systems specially adapted for, or arranged on, internal-combustion engines
    • F02M35/10—Air intakes; Induction systems
    • F02M35/10242—Devices or means connected to or integrated into air intakes; Air intakes combined with other engine or vehicle parts
    • F02M35/10295—Damping means, e.g. tranquillising chamber to dampen air oscillations
    • 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

Definitions

  • the invention relates to an intake manifold for a multi-cylinder engine, in which a plurality of manifold branches are branched from a surge tank connected to an intake passage and the manifold branches are connected to the respective intake ports of the multi-cylinder engine.
  • a multi-cylinder engine which is for example a four-cylinder engine, is provided with an intake manifold through which an intake passage is connected to the respective intake ports of the engine.
  • an intake manifold typically, a plurality of manifold branches are branched from a surge tank that is connected to the intake passage and suppresses the pulsation of intake air, and the manifold branches are connected to the respective intake ports of the multi-cylinder engine. That is, in such multi-cylinder engines, intake air is drawn into the intake passage and then into the surge tank, after which the intake air flows from the surge tank into the respective manifold branches and then reach the respective combustion chambers via the intake ports for the respective cylinders.
  • 2004-308626 recites a multi-piece resin-made intake manifold that is consisted of two or more resin parts are joined together by welding such that the directions of the welding lines in the manifold branches of the intake manifold match the flow direction of intake air. This structure reduces the interference to the intake air flow and the intake air pulsations from the welding lines, thus effectively suppressing the reduction of the volumetric efficiency due to the pressure loss of intake air.
  • the volumetric efficiency can be reliably maintained high by forming the welding lines along the flow direction of intake air flow in the intake manifold as described above.
  • the time period corresponding to the intake stroke of one cylinder partially overlap the time period corresponding to the intake stroke of another cylinder, and the reduction of the volumetric efficiency due to such intake stroke time overlapping is not negligible.
  • FIG 14 illustrates the stroke transition of each cylinder of a four-cylinder engine in a typical combustion cycle.
  • ignition is performed in the order of the first cylinder #1, the third cylinder #3, the fourth cylinder #4, and the second cylinder #2.
  • partial intake stroke overlapping occurs during, for example, the time period corresponding to the latter stage of the intake stroke of the first cylinder #1 and the initial stage of the intake stroke of the third cylinder #3, the time period corresponding to the latter stage of the intake stroke of the third cylinder #3 and the initial stage of the intake stroke of the fourth cylinder #4, the time period corresponding to the latter stage of the intake stroke of the fourth cylinder #4 and the initial stage of the intake stroke of the second cylinder #2, the time period corresponding to the latter stage of the intake stroke of the second cylinder #2 and the initial stage of the intake stroke of the first cylinder #1.
  • the manifold branches are branched from the surge tank and the openings of the respective manifold branches are formed in an inner face of the surge tank. Therefore, for example, when the intake stroke of the fourth cylinder #4 starts in the latter stage of the intake stroke of the third cylinder #3, a portion of the intake air flowing, in the surge tank, into the opening of the manifold branch for the third cylinder #3 is drawn into the opening of the manifold branch for the fourth cylinder #4. In this case, the intake air pulsation pressure for the third cylinder #3 decreases, and the volumetric efficiency of the third cylinder #3 decreases accordingly. This phenomenon occurs to other cylinders.
  • the invention provides an intake manifold for a multi-cylinder engine, having a surge tank connected to an intake passage of the multi-cylinder engine and a plurality of manifold branches extending from manifold branch openings provided in an inner face of the surge tank to intake ports of the multi-cylinder engine, wherein at least one partition is provided on the inner face of the surge tank at a position between the manifold branch openings.
  • the manifold branch openings for the respective cylinders are formed in an inner face of the surge tank.
  • first cylinder if the latter stage of the intake stroke of a certain cylinder (will be referred to as "first cylinder") overlaps the initial stage of the intake stroke of other cylinder (will be referred to as "second cylinder), a portion of the intake air flowing into the manifold branch opening for the first cylinder is drawn into the manifold branch opening for the second cylinder, and this results in a decrease in the volumetric efficiency of the first cylinder.
  • the above-described intake manifold according to the invention may be such that, assuming that the inner face of the surge tank is the bottom face of the surge tank, the end of partition, for example, on the side opposite from where intake air flows into the surge tank extends to a side face of the surge tank.
  • the above-described intake manifold according to the invention may be such that the multi-cylinder engine is a four-cylinder engine having a first cylinder, a second cylinder, a third cylinder, and a fourth cylinder that are arranged in numeric order from one side to the other side of the multi-cylinder engine and one of the partitions is provided between the manifold branch opening for the first cylinder and the manifold branch opening for the second cylinder and the other of the partitions is provided between the manifold branch opening for the third cylinder and the manifold branch opening for the fourth cylinder.
  • the above-described intake manifold according to the invention may be such that the end of one of the partitions on the side where intake air flows into the surge tank and the end of the other of the partitions on the side where intake air flows into the surge tank are connected to each other.
  • the above-described intake manifold according to the invention may be such that one of the partitions is formed generally in the shape of the letter "L” having an extension portion that extends toward the side of the manifold branch opening for the second cylinder from the end of the same partition on the side where intake air flows into the surge tank, and the other of the partitions is formed generally in the shape of the letter "L” having an extension portion that extends toward the side of the manifold branch opening for the third cylinder from the end of the same partition on the side where intake air flows into the surge tank.
  • the intake air backflows between the manifold branch openings can be more reliably suppressed.
  • the above-described intake manifold according to the invention may be such that the multi-cylinder engine is a four-cylinder engine having a first cylinder, a second cylinder, a third cylinder, and a fourth cylinder that are arranged in numeric order from one side to the other side of the multi-cylinder engine and the partition is provided between the manifold branch opening for the second cylinder and the manifold branch opening for the third cylinder.
  • the intake air backflows can occur also between the branch pipe opening for the first cylinder #1 and the branch pipe opening for the third cylinder #3 and between the branch pipe opening for the fourth cylinder #4 and the branch pipe opening for the second cylinder #2.
  • the partition is provided between the manifold branch opening for the second cylinder and the manifold branch opening for the third cylinder of the four-cylinder engine, the intake air backflows can be effectively suppressed between the manifold branch openings for the intake-stroke-time-overlapping cylinders.
  • the above-described intake manifold according to the invention may be such that the partition is formed generally in the shape of the letter "T" having an extension portion that extends toward the side of the manifold branch opening for the second cylinder from the end of the partition on the side where intake air flows into the surge tank and another extension portion that extends toward the side of the manifold branch opening for the third cylinder from the same end of the partition.
  • the above-described intake manifold according to the invention may be such that the partition is formed generally in the shape of the letter "Y" having an extension portion that extends toward the side of the manifold branch opening for the second cylinder from the end of the partition on the side where intake air flows into the surge tank 11 and another extension portion that extends toward the side of the manifold branch opening for the third cylinder from the same end of the partition. According to these structures, the intake air backflows between the manifold branch openings can be more reliably suppressed.
  • the above-described intake manifold according to the invention may be such that the multi-cylinder engine is a four-cylinder engine having a first cylinder, a second cylinder, a third cylinder, and a fourth cylinder that are arranged in numeric order from one side to the other side of the multi-cylinder engine and a first one of the partitions is provided between the manifold branch opening for the first cylinder and the manifold branch opening for the second cylinder, a second one of the partitions is provided between the manifold branch opening for the third cylinder and the manifold branch opening for the fourth cylinder, and a third one of the partitions is provided between the manifold branch opening for the second cylinder and the manifold branch opening for the third cylinder.
  • this intake manifold may be such that, for example, an end of the partition provided between the manifold branch opening for the first cylinder and the manifold branch opening for the second cylinder and an end of the partition provided between the manifold branch opening for the third cylinder and the manifold branch opening for the fourth cylinder are connected to each other, the ends of the partitions being located on the side where intake air flows into the surge tank. According to this structure, the intake air backflows between the manifold branch openings can be more reliably suppressed.
  • the height of the partition may be lower than the height of a side face of the surge tank, and more specifically, the height of the partition may be approximately one-fourth the diameter of each of the manifold branch openings.
  • FIG 1 is a perspective view showing the structure of an intake manifold for a multi-cylinder engine according to the first example embodiment of the invention
  • FIG 2 is a cutaway view that cuts through the intake manifold according to the first example embodiment of the invention along the single-dotted line A in FIG 1;
  • FIG 3 shows is a cross-sectional view schematically showing the structure of the portion of the intake manifold according to the first example embodiment of the invention where a surge tank is formed;
  • FIG 4A is a graph indicating how the intake air pulsation pressure changed with respect to the crank angle while the four-cylinder engine incorporating an intake manifold according to the first example embodiment of the invention is running at 3500 rpm;
  • FIG 4B is a graph indicating how the intake air pulsation pressure changed with respect to the crank angle while a four-cylinder engine incorporating a conventional intake manifold is running at 3500 rpm;
  • FIG 5 is a graph illustrating the variation of the volumetric efficiency of a four-cylinder engine incorporating an intake manifold according to the first example embodiment of the invention with respect to the engine speed in comparison with the same volumetric efficiency variation of a four-cylinder engine incorporating a conventional intake manifold;
  • FIG 6 is a cross-sectional view schematically showing the structure of the portion of an intake manifold according to the first modification example of the first example embodiment of the invention where a surge tank is formed;
  • FIG 7 is a cross-sectional view schematically showing the structure of the portion of an intake manifold according to the second modification example of the first example embodiment of the invention where a surge tank is formed;
  • FIG 8 is a cross-sectional view schematically showing the structure of the portion of an intake manifold according to the second example embodiment of the invention where a surge tank is formed;
  • FIG 9 is a graph illustrating the variation of the volumetric efficiency of a four-cylinder engine incorporating an intake manifold according to the second example embodiment with respect to the engine speed in comparison with the same volumetric efficiency variation of a four-cylinder engine incorporating an intake manifold according to the first example embodiment and the same volumetric efficiency variation of a four-cylinder engine incorporating a conventional intake manifold;
  • FIG 10 is a cross-sectional view schematically showing the structure of the portion of an intake manifold according to the first modification example of the second example embodiment of the invention where a surge tank is formed;
  • FIG 11 is a cross-sectional view schematically showing the structure of the portion of an intake manifold according to the second modification example of the second example embodiment of the invention where a surge tank is formed;
  • FIG 12 is a cross-sectional view schematically showing the structure of the portion of an intake manifold according to another example embodiment of the invention where a surge tank is formed;
  • FIG 13 is a cross-sectional view schematically showing the structure of the portion of an intake manifold according to still another embodiment of the invention where a surge tank is formed;
  • FIG 14 is a stroke chart illustrating the relation between the cycle of each cylinder of a typical four-cylinder engine and its crank angle.
  • FIG 1 to 5 an intake manifold for a multi-cylinder engine according to the first example embodiment of the invention will be described with reference to FIG 1 to 5.
  • the intake manifold of the first example embodiment is incorporated in a four-cylinder engine. In this four-cylinder engine, ignition is performed in the order of the first cylinder #1, the third cylinder #3, the fourth cylinder #4, and the second cylinder #2.
  • FIG. 1 is a perspective view showing the structure of the intake manifold of the first example embodiment.
  • FIG 2 is a cutaway view taken along the single-dotted line A in FIG 1.
  • a surge tank 11 having a rectangular cross section is formed in the intake manifold.
  • a communication passage 12 which is connected to the intake passage of the engine and through which the intake passage and the inside of the surge tank 11 communicate with each other is formed at the left side of the surge tank 11 as viewed in FIG 2, and intake air is drawn from the intake passage into the surge tank 11 via the communication passage 12.
  • manifold branch openings 13a to 13d are formed in an inner face of the surge tank 11 (the bottom face of the surge tank 11 when viewed in FIG 2, and will be referred to as "bottom face") and manifold branches 20a to 2Od extend through the front side, the bottom side, the rear side, and the upper side of the intake manifold in this order as shown in FIG 1.
  • Flanges 21 are formed at the openings of the manifold branches 20a to 2Od to which the manifold branch openings 13a to 13d lead, and the manifold branches 20a to 2Od are connected to the intake ports for the first to fourth cylinders #l-#4 via the respective flanges 21.
  • the manifold branch opening 13a formed in the surge tank 11 as shown in FIG 2 is connected to the intake port for the first cylinder #1 via the manifold branch 20a
  • the manifold branch opening 13b is connected to the intake port for the second cylinder #2 via the manifold branch 20b
  • the manifold branch opening 13c is connected to the intake port for the third cylinder #3 via the manifold branch 20c
  • the manifold branch opening 13d is connected to the intake port for the forth cylinder #4 via the manifold branch 2Od.
  • intake air flows from the intake passage into the surge tank 11 via the communication passage 12, and the intake air then flows into the manifold branches 20a to 2Od via the manifold branch openings 13a to 13d and then reach the combustion chambers of the respective cylinders #1 to #4.
  • FIG 3 schematically shows the structure of the portion of the intake manifold where the surge tank 11 is formed as viewed from above.
  • the partition 14a is provided between the manifold branch opening 13a for the first cylinder #1 and the manifold branch opening 13b for the second cylinder #2
  • the partition 14b is provided between the manifold branch opening 13c for the third cylinder #3 and the manifold branch opening 13d for the fourth cylinder #4.
  • the partition 14c is provided such that the end of the partition 14a on the side where intake air flows into the surge tank 11 and the end of the partition 14b on the same side are connected to each other via the partition 14c.
  • FIG 4A illustrates the result of measurement of the intake air pulsation pressure that occurred during the actual operation of a four-cylinder engine incorporating an intake manifold structured according to the first example embodiment.
  • FIG 4B illustrates the result of measurement of the intake air pulsation pressure that occurred during the actual operation of a four-cylinder engine incorporating an intake manifold not having the partitions 14a to 14c, that is, a conventional intake manifold.
  • FIG 4A indicates how the intake air pulsation pressure changed with respect to the crank angle while the four-cylinder engine incorporating the intake manifold of the first example embodiment is running at 3500 rpm
  • FIG 4B indicates how the intake air pulsation pressure changed with respect to the crank angle while the four-cylinder engine incorporating the intake manifold not having the partitions 14a to 14c is running at 3500 rpm.
  • the maximum value of the intake air pulsation pressure in the latter stage of the intake stroke of the second cylinder #2 is much smaller than the maximum value of the intake air pulsation pressure in the latter stage of the intake pressure of the first cylinder #1.
  • the maximum value of the intake air pulsation pressure of the second cylinder #2 in the latter stage of its intake stroke is substantially equal to the maximum value of the intake air pulsation pressure of the first cylinder #1 in the latter stage of its intake stroke
  • the maximum value of the intake air pulsation pressure of the third cylinder #3 in the latter stage of its intake stroke is substantially equal to the maximum value of the intake air pulsation pressure of the fourth cylinder #4 in the latter stage of its intake stroke.
  • FIG 5 illustrates the variation of the volumetric efficiency of a four-cylinder engine incorporating the intake manifold of the first example embodiment with respect to the engine speed in comparison with the same volumetric efficiency variation of a four-cylinder engine incorporating an intake manifold with no partitions.
  • the variation of the volumetric efficiency of the four-cylinder engine incorporating the intake manifold of the first example embodiment is indicated by the solid sequential line and the variation of the volumetric efficiency of the four-cylinder engine incorporating the intake manifold with no partitions is indicated by the single-dotted sequential line.
  • the volumetric efficiency of the engine incorporating the intake manifold of the first example embodiment is lower than the volumetric efficiency of the engine incorporating the intake manifold with no partitions in the engine speed ranges near 2750 rpm and 5250 rpm, but is higher than the volumetric efficiency of the engine incorporating the intake manifold with no partitions in other engine speed ranges.
  • the partition 14a is provided on the bottom face of the surge tank 11 at the position between the manifold branch opening 13a for the first cylinder #1 and the manifold branch opening 13b for the second cylinder #2 and the partition 14b is provided on the bottom face of the surge tank 11 at the position between the manifold branch opening 13c for the third cylinder #3 and the manifold branch opening 13d for the fourth cylinder #4.
  • This structure reliably suppresses the intake air backflows between the manifold branch openings for the two cylinders that are fired consecutively, that is, between the manifold branch opening 13c for the third cylinder #3 and the manifold branch opening 13d for the fourth cylinder #4, and the manifold branch opening 13b for the second cylinder #2 and the manifold branch opening 13a for the first cylinder #1. Further, because the partition 14a and the partition 14b are connected to each other via the partition 14c, the effect of suppressing the intake air backflows is enhanced.
  • FIG 6 shows the first modification example of the intake manifold of the first example embodiment.
  • partitions 114a, 114b are formed on the bottom face of the surge tank 11 in place of the partitions 14a to 14c.
  • the partition 114a is formed generally in the shape of the letter "L” having an extension portion that extends toward the side of the manifold branch opening 13b for the second cylinder #2 from the end of the partition 114a on the side where intake air flows into the surge tank 11, and likewise, the partition 114b is formed generally in the shape of the letter "L” having an extension portion that extends toward the side of the manifold branch opening 13c for the third cylinder #3 from the end of the partition 114b on the side where intake air flows into the surge tank 11.
  • This partition arrangement provides effects that are the same as or similar to those obtained in the first example embodiment.
  • FIG 7 shows the second modification example of the intake manifold of the first example embodiment.
  • this modification example as shown in FIG 7, only the partitions 14a, 14b among the partitions 14a to 14c of the intake manifold of the first example embodiment are provided on the bottom face of the surge tank 11.
  • This structure also provides effects that are the same as or similar to those obtained in the first example embodiment if the height of each partition 14a, 14b and the intake air distribution are appropriately set.
  • an intake manifold for a multi-cylinder engine according to the second example embodiment of the invention will be described with reference to FIG 8 and FIG 9. This intake manifold is incorporated in a four-cylinder engine as in the first example embodiment.
  • the intake manifold of the second example embodiment is particularly different from the intake manifold of the first example embodiment in that the intake manifold of the second example embodiment is configured to suppress the intake air backflows between the manifold branch opening 13a for the first cylinder #1 and the manifold branch opening 13c for the third cylinder #3 and between the manifold branch opening 13d for the fourth cylinder #4 and the manifold branch opening 13b for the second cylinder #2.
  • the intake manifold of the second example embodiment will be described with focus on the differences from the intake manifold of the first example embodiment. Note that the appearance of the intake manifold of the second example embodiment is the same as that of the intake manifold of the first example embodiment shown in FIG 1 and FIG 2.
  • FIG 8 corresponds FIG 3, schematically showing the structure of the portion of the intake manifold where the surge tank 11 is formed as viewed from above.
  • a partition 214 is provided on the bottom face of the surge tank 11 at a position between the manifold branch opening 13b for the second cylinder #2 and the manifold branch opening 13c for the third cylinder #3. This arrangement of the partition 214 suppresses the intake air backflows between the manifold branch opening 13a and the manifold branch opening 13c and between the manifold branch opening 13b and the manifold branch opening 13d.
  • FIG 9 illustrates the variation of the volumetric efficiency of the four-cylinder engine incorporating the intake manifold of the second example embodiment with respect to the engine speed in comparison with the same volumetric efficiency variation of a four-cylinder engine incorporating an intake manifold with no partitions.
  • the variation of the volumetric efficiency of the four-cylinder engine incorporating the intake manifold of the second example embodiment is indicated by the solid sequential line
  • the variation of the volumetric efficiency of the four-cylinder engine incorporating the intake manifold with no partitions is indicated by the single-dotted sequential line
  • the variation of the volumetric efficiency of the four-cylinder engine incorporating the intake manifold of the first example embodiment is indicated by the double-dotted sequential line.
  • the volumetric efficiency of the engine incorporating the intake manifold of the second example embodiment is lower than the volumetric efficiency of the engine incorporating the intake manifold with no partitions in, for example, the engine speed range near 5250 rpm, but is higher than the volumetric efficiency of the engine incorporating the intake manifold with no partitions in other engine speed ranges.
  • the volumetric efficiency of the engine incorporating the intake manifold of the second example embodiment is just slightly lower than the volumetric efficiency of the engine incorporating the intake manifold of the first example embodiment in the speed ranges other than those near 2750 rpm and 4500 rpm.
  • the partition 214 is provided on the bottom face of the surge tank 11 at the position between the manifold branch opening 13b for the second cylinder #2 and the manifold branch opening 13c for the third cylinder #3, the intake air backflows are effectively suppressed between the manifold branch opening 13a for the first cylinder #1 and the manifold branch opening 13c for the third cylinder #3 and the manifold branch opening 13d for the fourth cylinder #4 and the manifold branch opening 13b for the second cylinder #2.
  • FIG 10 shows the first modification example of the intake manifold of the second example embodiment.
  • a partition 314 is provided on the bottom face of the surge tank 11 in place of the partition 214 of the second example embodiment.
  • the partition 314 is formed generally in the shape of the letter "T" having two extension portions, one extending toward the side of the manifold branch opening 13b for the second cylinder #2 from the end of the partition 314 on the side where intake air flows into the surge tank 11 and the other extending toward the side of the manifold branch opening 13c for the third cylinder #3 from the same end of the partition 314. According to this structure, the intake air backflows can be more reliably suppressed between the respective manifold branch openings.
  • FIG 11 shows the second modification example of the intake manifold of the second example embodiment.
  • a partition 414 is provided on the bottom face of the surge tank 11 in place of the partition 214 of the intake manifold of the second example embodiment.
  • the partition 414 is formed generally in the shape of the letter "Y" having two extension portions, one extending toward the side of the manifold branch opening 13b for the second cylinder #2 from the end of the partition 314 on the side where intake air flows into the surge tank 11 and the other extending toward the side of the manifold branch opening 13c for the third cylinder #3 from the same end of the partition 314. According to this structure, the intake air backflows can be more reliably suppressed between the respective manifold branch openings.
  • intake manifolds for a multi-cylinder engine will be described with reference to FIG 12 and FIG 13.
  • Each of these intake manifolds is incorporated in a four-cylinder engine as in the foregoing example embodiments.
  • partitions 514a to 514c are provided on the bottom face of the surge tank 11.
  • the partition 514a is provided between the manifold branch opening 13a for the first cylinder #1 and the manifold branch opening 13b for the second cylinder #2
  • the partition 514b is provided between the manifold branch opening 13c for the third cylinder #3 and the manifold branch opening 13d for the fourth cylinder #4
  • the partition 514c is provided between the manifold branch opening 13b for the second cylinder #2 for the second cylinder #2 and the manifold branch opening 13c for the third cylinder #3.
  • partitions 514a to 514d are provided on the bottom face of the surge tank 11.
  • the partition 514d is provided on the bottom face of the surge tank 11 in addition to the partitions 514a to 514c shown in FIG 12, such that the end of the partition 514a on the side where intake air flows into the surge tank 11 and the end of the partition 514b on the same side are connected to each other via the partition 514d. According to this structure, the intake air backflows can be more reliably suppressed between the manifold branch openings.
  • the partitions 514a, 514b of the intake manifold shown in FIG 12 may be replaced by the partitions 114a, 114b shown in FIG 6.
  • the partition 514c of the intake manifold shown in FIG 12 may be replaced by the partition 314 shown in FIG 10.
  • the partition 514c of the intake manifold shown in FIG 12 may be replaced by the partition 414 shown in FIG 11.
  • each partition extends to a side face of the surge tank 11. According to this structure, the intake air backflows can be more reliably suppressed between the manifold branch openings.
  • an intake manifold according to the invention may be embodied in various forms with at least one partition being formed upright on the bottom face of the surge tank at a position between two or more manifold branch openings so as to suppress the intake air backflow between the manifold branch openings.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Geometry (AREA)
  • Characterised By The Charging Evacuation (AREA)

Abstract

For example, the intake manifold of a four-cylinder engine has a plurality of manifold branches that extend from corresponding manifold branch openings (13a to 13d) provided in an inner face of a surge tank (11). On that inner face of the surge tank (11), a partition (14a) is provided between the manifold branch opening (13a) for the first cylinder (#1) and the manifold branch opening (13b) for the second cylinder (#2), and another partition (14b) is provided between the manifold branch opening (13c) for the third cylinder (#3) and the manifold branch opening (13d) for the fourth cylinder (#4).

Description

INTAKE MANIFOLD FOR MULTI-CYLINDER ENGINE
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The invention relates to an intake manifold for a multi-cylinder engine, in which a plurality of manifold branches are branched from a surge tank connected to an intake passage and the manifold branches are connected to the respective intake ports of the multi-cylinder engine.
2. Description of the Related Art
[0002] A multi-cylinder engine, which is for example a four-cylinder engine, is provided with an intake manifold through which an intake passage is connected to the respective intake ports of the engine. In such an intake manifold, typically, a plurality of manifold branches are branched from a surge tank that is connected to the intake passage and suppresses the pulsation of intake air, and the manifold branches are connected to the respective intake ports of the multi-cylinder engine. That is, in such multi-cylinder engines, intake air is drawn into the intake passage and then into the surge tank, after which the intake air flows from the surge tank into the respective manifold branches and then reach the respective combustion chambers via the intake ports for the respective cylinders.
[0003] Meanwhile, in engines, it is also important to improve the volumetric efficiency by utilising the compression waves of intake air that occur in the respective intake manifold branches and the respective intake ports, that is, intake air pulsations. In the case of multi-cylinder engines, such as the one described above, in particular, the intake air pulsations in the respective intake manifold branches and intake ports need to be precisely matched with the cycles at which the intake strokes are executed in the respective cylinders, and the cycles of the intake air pulsations, the pressures of the intake air pulsation, and so on, need to be accurately ascertained and reflected to the designing. For example, Japanese Patent Application Publication No. 2004-308626 recites a multi-piece resin-made intake manifold that is consisted of two or more resin parts are joined together by welding such that the directions of the welding lines in the manifold branches of the intake manifold match the flow direction of intake air. This structure reduces the interference to the intake air flow and the intake air pulsations from the welding lines, thus effectively suppressing the reduction of the volumetric efficiency due to the pressure loss of intake air.
[0004] It is true that the volumetric efficiency can be reliably maintained high by forming the welding lines along the flow direction of intake air flow in the intake manifold as described above. However, in multi-cylinder engines, it is often the case that the time period corresponding to the intake stroke of one cylinder partially overlap the time period corresponding to the intake stroke of another cylinder, and the reduction of the volumetric efficiency due to such intake stroke time overlapping is not negligible.
[0005] FIG 14 illustrates the stroke transition of each cylinder of a four-cylinder engine in a typical combustion cycle. Referring to FIG 14, in this four-cylinder engine, ignition is performed in the order of the first cylinder #1, the third cylinder #3, the fourth cylinder #4, and the second cylinder #2. In this engine, partial intake stroke overlapping occurs during, for example, the time period corresponding to the latter stage of the intake stroke of the first cylinder #1 and the initial stage of the intake stroke of the third cylinder #3, the time period corresponding to the latter stage of the intake stroke of the third cylinder #3 and the initial stage of the intake stroke of the fourth cylinder #4, the time period corresponding to the latter stage of the intake stroke of the fourth cylinder #4 and the initial stage of the intake stroke of the second cylinder #2, the time period corresponding to the latter stage of the intake stroke of the second cylinder #2 and the initial stage of the intake stroke of the first cylinder #1. Further, in the intake manifold of such a four-cylinder engine, as mentioned above, the manifold branches are branched from the surge tank and the openings of the respective manifold branches are formed in an inner face of the surge tank. Therefore, for example, when the intake stroke of the fourth cylinder #4 starts in the latter stage of the intake stroke of the third cylinder #3, a portion of the intake air flowing, in the surge tank, into the opening of the manifold branch for the third cylinder #3 is drawn into the opening of the manifold branch for the fourth cylinder #4. In this case, the intake air pulsation pressure for the third cylinder #3 decreases, and the volumetric efficiency of the third cylinder #3 decreases accordingly. This phenomenon occurs to other cylinders.
SUMMARY OF THE INVENTION
[0006] It is an object of the invention to provide an intake manifold for a multi-cylinder engine, which effectively suppresses the reduction of the volumetric efficiency due to intake stroke time overlapping even if the intake manifold branches for the respective cylinders are branched from a single surge tank.
[0007] The invention provides an intake manifold for a multi-cylinder engine, having a surge tank connected to an intake passage of the multi-cylinder engine and a plurality of manifold branches extending from manifold branch openings provided in an inner face of the surge tank to intake ports of the multi-cylinder engine, wherein at least one partition is provided on the inner face of the surge tank at a position between the manifold branch openings.
[0008] In an intake manifold in which manifold branches for the respective cylinders of a multi-cylinder engine are branched from a single surge tank as described above, the manifold branch openings for the respective cylinders are formed in an inner face of the surge tank. In a multi-cylinder engine incorporating such an intake manifold, if the latter stage of the intake stroke of a certain cylinder (will be referred to as "first cylinder") overlaps the initial stage of the intake stroke of other cylinder (will be referred to as "second cylinder), a portion of the intake air flowing into the manifold branch opening for the first cylinder is drawn into the manifold branch opening for the second cylinder, and this results in a decrease in the volumetric efficiency of the first cylinder. However, even in the case where manifold branches for the respective cylinders of a multi-cylinder engine are branched from a single surge tank, by providing at lease one partition on an inner face of the surge tank so as to suppress the backflow of intake air between the manifold branch openings for the respective cylinders, it is possible to prevent a portion of intake air flowing into the manifold branch opening for a certain cylinder from being drawn into the manifold opening for other cylinder, and therefore the reduction of the volumetric efficiency due to the aforementioned intake stroke time overlapping can be effectively suppressed.
[0009] Further, the above-described intake manifold according to the invention may be such that, assuming that the inner face of the surge tank is the bottom face of the surge tank, the end of partition, for example, on the side opposite from where intake air flows into the surge tank extends to a side face of the surge tank.
[0010] Further, the above-described intake manifold according to the invention may be such that the multi-cylinder engine is a four-cylinder engine having a first cylinder, a second cylinder, a third cylinder, and a fourth cylinder that are arranged in numeric order from one side to the other side of the multi-cylinder engine and one of the partitions is provided between the manifold branch opening for the first cylinder and the manifold branch opening for the second cylinder and the other of the partitions is provided between the manifold branch opening for the third cylinder and the manifold branch opening for the fourth cylinder.
[0011] As in the example illustrated in FIG 14, in four-cylinder engines, ignition is performed typically in the order of the first cylinder #1, the third cylinder #3, the fourth cylinder #4, and the second cylinder #2. In general, when the manifold branch openings for two cylinders that are fired consecutively are formed in an inner face of the surge tank at the positions adjacent to each other, the aforementioned intake air backflows easily occur. More specifically, in this case, the intake air backflows tend to occur between the manifold branch opening for the third cylinder #3 and the manifold branch opening for the fourth cylinder #4 and between the manifold branch opening for the first cylinder #1 and the manifold branch opening for the second cylinder #2. Therefore, in the foregoing four-cylinder engine structure in which a partition is provided between the manifold branch opening for the first cylinder and the manifold branch opening for the second cylinder and another partition is provided between the manifold branch opening for the third cylinder and the manifold branch opening for the fourth cylinder, the intake air backflows can be reliably suppressed between the adjacent manifold branch openings.
[0012] For example, the above-described intake manifold according to the invention may be such that the end of one of the partitions on the side where intake air flows into the surge tank and the end of the other of the partitions on the side where intake air flows into the surge tank are connected to each other. Further, the above-described intake manifold according to the invention may be such that one of the partitions is formed generally in the shape of the letter "L" having an extension portion that extends toward the side of the manifold branch opening for the second cylinder from the end of the same partition on the side where intake air flows into the surge tank, and the other of the partitions is formed generally in the shape of the letter "L" having an extension portion that extends toward the side of the manifold branch opening for the third cylinder from the end of the same partition on the side where intake air flows into the surge tank. According to these structures, the intake air backflows between the manifold branch openings can be more reliably suppressed.
[0013] Further, the above-described intake manifold according to the invention may be such that the multi-cylinder engine is a four-cylinder engine having a first cylinder, a second cylinder, a third cylinder, and a fourth cylinder that are arranged in numeric order from one side to the other side of the multi-cylinder engine and the partition is provided between the manifold branch opening for the second cylinder and the manifold branch opening for the third cylinder.
[0014] As already mentioned, in four-cylinder engines, ignition is typically performed in the order of the first cylinder #1, the third cylinder #3, the fourth cylinder #4, and the second cylinder #2. As long as the respective manifold branches are branched from a single surge tank, the aforementioned intake air backflows can occur not only between the adjacent manifold branch openings in the inner face of the surge tank, but also between any two non-adjacent manifold branch openings if the time periods of the intake strokes of the cylinders corresponding to the two manifold branch openings overlap each other. That is, in this case, the intake air backflows can occur also between the branch pipe opening for the first cylinder #1 and the branch pipe opening for the third cylinder #3 and between the branch pipe opening for the fourth cylinder #4 and the branch pipe opening for the second cylinder #2. Regarding this point, in the case of the foregoing structure, because the partition is provided between the manifold branch opening for the second cylinder and the manifold branch opening for the third cylinder of the four-cylinder engine, the intake air backflows can be effectively suppressed between the manifold branch openings for the intake-stroke-time-overlapping cylinders. Meanwhile, there are also four-cylinder engines in which ignition is performed in the order of the first cylinder #1, the third cylinder #3, the second cylinder #2, and the fourth cylinder #4. In such four-cylinder engines, based on the same principal as the one of the foregoing structure in which a partition is provided between the manifold branch opening for the first cylinder and the manifold branch opening for the second cylinder and another partition is provided between the manifold branch opening for the third cylinder and the manifold branch opening for the fourth cylinder, the intake air backflows can be reliably suppressed between the manifold branch opening for the second cylinder and the manifold branch opening for the third cylinder.
[0015] For example, the above-described intake manifold according to the invention may be such that the partition is formed generally in the shape of the letter "T" having an extension portion that extends toward the side of the manifold branch opening for the second cylinder from the end of the partition on the side where intake air flows into the surge tank and another extension portion that extends toward the side of the manifold branch opening for the third cylinder from the same end of the partition. Further, the above-described intake manifold according to the invention may be such that the partition is formed generally in the shape of the letter "Y" having an extension portion that extends toward the side of the manifold branch opening for the second cylinder from the end of the partition on the side where intake air flows into the surge tank 11 and another extension portion that extends toward the side of the manifold branch opening for the third cylinder from the same end of the partition. According to these structures, the intake air backflows between the manifold branch openings can be more reliably suppressed.
[0016] Further, the above-described intake manifold according to the invention may be such that the multi-cylinder engine is a four-cylinder engine having a first cylinder, a second cylinder, a third cylinder, and a fourth cylinder that are arranged in numeric order from one side to the other side of the multi-cylinder engine and a first one of the partitions is provided between the manifold branch opening for the first cylinder and the manifold branch opening for the second cylinder, a second one of the partitions is provided between the manifold branch opening for the third cylinder and the manifold branch opening for the fourth cylinder, and a third one of the partitions is provided between the manifold branch opening for the second cylinder and the manifold branch opening for the third cylinder.
[0017] According to this structure, because a partition is provided between the manifold branch openings for the first and second cylinders, another partition is provided between the manifold branch openings for the third and fourth cylinders, and another partition is provided between the manifold branch openings for the second and third cylinders, synergetic effects of the case where a partition is provided between the manifold branch openings for the first and second cylinders and another partition is provided between the manifold branch openings for the third and fourth cylinders and the case where a partition is provided between the manifold branch openings for the second and third cylinders can be obtained.
[0018] Further, this intake manifold may be such that, for example, an end of the partition provided between the manifold branch opening for the first cylinder and the manifold branch opening for the second cylinder and an end of the partition provided between the manifold branch opening for the third cylinder and the manifold branch opening for the fourth cylinder are connected to each other, the ends of the partitions being located on the side where intake air flows into the surge tank. According to this structure, the intake air backflows between the manifold branch openings can be more reliably suppressed. [0019] In the foregoing intake manifolds, the height of the partition may be lower than the height of a side face of the surge tank, and more specifically, the height of the partition may be approximately one-fourth the diameter of each of the manifold branch openings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The foregoing and further objects, features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings, wherein like numerals are used to represent like elements and wherein:
FIG 1 is a perspective view showing the structure of an intake manifold for a multi-cylinder engine according to the first example embodiment of the invention;
FIG 2 is a cutaway view that cuts through the intake manifold according to the first example embodiment of the invention along the single-dotted line A in FIG 1;
FIG 3 shows is a cross-sectional view schematically showing the structure of the portion of the intake manifold according to the first example embodiment of the invention where a surge tank is formed;
FIG 4A is a graph indicating how the intake air pulsation pressure changed with respect to the crank angle while the four-cylinder engine incorporating an intake manifold according to the first example embodiment of the invention is running at 3500 rpm;
FIG 4B is a graph indicating how the intake air pulsation pressure changed with respect to the crank angle while a four-cylinder engine incorporating a conventional intake manifold is running at 3500 rpm;
FIG 5 is a graph illustrating the variation of the volumetric efficiency of a four-cylinder engine incorporating an intake manifold according to the first example embodiment of the invention with respect to the engine speed in comparison with the same volumetric efficiency variation of a four-cylinder engine incorporating a conventional intake manifold;
FIG 6 is a cross-sectional view schematically showing the structure of the portion of an intake manifold according to the first modification example of the first example embodiment of the invention where a surge tank is formed;
FIG 7 is a cross-sectional view schematically showing the structure of the portion of an intake manifold according to the second modification example of the first example embodiment of the invention where a surge tank is formed;
FIG 8 is a cross-sectional view schematically showing the structure of the portion of an intake manifold according to the second example embodiment of the invention where a surge tank is formed;
FIG 9 is a graph illustrating the variation of the volumetric efficiency of a four-cylinder engine incorporating an intake manifold according to the second example embodiment with respect to the engine speed in comparison with the same volumetric efficiency variation of a four-cylinder engine incorporating an intake manifold according to the first example embodiment and the same volumetric efficiency variation of a four-cylinder engine incorporating a conventional intake manifold;
FIG 10 is a cross-sectional view schematically showing the structure of the portion of an intake manifold according to the first modification example of the second example embodiment of the invention where a surge tank is formed;
FIG 11 is a cross-sectional view schematically showing the structure of the portion of an intake manifold according to the second modification example of the second example embodiment of the invention where a surge tank is formed;
FIG 12 is a cross-sectional view schematically showing the structure of the portion of an intake manifold according to another example embodiment of the invention where a surge tank is formed;
FIG 13 is a cross-sectional view schematically showing the structure of the portion of an intake manifold according to still another embodiment of the invention where a surge tank is formed;
FIG 14 is a stroke chart illustrating the relation between the cycle of each cylinder of a typical four-cylinder engine and its crank angle. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0021] Hereinafter, an intake manifold for a multi-cylinder engine according to the first example embodiment of the invention will be described with reference to FIG 1 to 5. The intake manifold of the first example embodiment is incorporated in a four-cylinder engine. In this four-cylinder engine, ignition is performed in the order of the first cylinder #1, the third cylinder #3, the fourth cylinder #4, and the second cylinder #2.
[0022] To begin with, the structure of the intake manifold of the first example embodiment will be described with reference to FIG 1 to FIG 3. FIG. 1 is a perspective view showing the structure of the intake manifold of the first example embodiment. FIG 2 is a cutaway view taken along the single-dotted line A in FIG 1. Referring to FIG 2, a surge tank 11 having a rectangular cross section is formed in the intake manifold. A communication passage 12 which is connected to the intake passage of the engine and through which the intake passage and the inside of the surge tank 11 communicate with each other is formed at the left side of the surge tank 11 as viewed in FIG 2, and intake air is drawn from the intake passage into the surge tank 11 via the communication passage 12. In this intake manifold, manifold branch openings 13a to 13d are formed in an inner face of the surge tank 11 (the bottom face of the surge tank 11 when viewed in FIG 2, and will be referred to as "bottom face") and manifold branches 20a to 2Od extend through the front side, the bottom side, the rear side, and the upper side of the intake manifold in this order as shown in FIG 1. Flanges 21 are formed at the openings of the manifold branches 20a to 2Od to which the manifold branch openings 13a to 13d lead, and the manifold branches 20a to 2Od are connected to the intake ports for the first to fourth cylinders #l-#4 via the respective flanges 21. That is, the manifold branch opening 13a formed in the surge tank 11 as shown in FIG 2 is connected to the intake port for the first cylinder #1 via the manifold branch 20a, the manifold branch opening 13b is connected to the intake port for the second cylinder #2 via the manifold branch 20b, the manifold branch opening 13c is connected to the intake port for the third cylinder #3 via the manifold branch 20c, and the manifold branch opening 13d is connected to the intake port for the forth cylinder #4 via the manifold branch 2Od. According to this structure, intake air flows from the intake passage into the surge tank 11 via the communication passage 12, and the intake air then flows into the manifold branches 20a to 2Od via the manifold branch openings 13a to 13d and then reach the combustion chambers of the respective cylinders #1 to #4.
[0023] In the intake manifold of the first example embodiment, as shown in FIG 2, partitions 14a to 14c are provided upright on the bottom face of the surge tank 11. The height of each partition 14a to 14c is large enough to suppress intake air backflows that may occur between the manifold branch openings 13a to 13d, and, for example, the partition height is set approximately one-fourth the diameter of each manifold branch opening 13a to 13d. FIG 3 schematically shows the structure of the portion of the intake manifold where the surge tank 11 is formed as viewed from above.
[0024] Referring to FIG 3, in the first example embodiment, the partition 14a is provided between the manifold branch opening 13a for the first cylinder #1 and the manifold branch opening 13b for the second cylinder #2, the partition 14b is provided between the manifold branch opening 13c for the third cylinder #3 and the manifold branch opening 13d for the fourth cylinder #4. The partition 14c is provided such that the end of the partition 14a on the side where intake air flows into the surge tank 11 and the end of the partition 14b on the same side are connected to each other via the partition 14c. By at least arranging the partitions 14a, 14b as described above, intake air backflows can be suppressed between the adjacent manifold branch openings 13a, 13b and between the adjacent manifold branch openings 13c, 13d., Further, connecting the partition 14a and the partition 14b by the partition 14c as described above enhances the effect of suppressing intake air backflows between the adjacent manifold branch openings.
[0025] FIG 4A illustrates the result of measurement of the intake air pulsation pressure that occurred during the actual operation of a four-cylinder engine incorporating an intake manifold structured according to the first example embodiment. FIG 4B, on the other hand, illustrates the result of measurement of the intake air pulsation pressure that occurred during the actual operation of a four-cylinder engine incorporating an intake manifold not having the partitions 14a to 14c, that is, a conventional intake manifold. More specifically, FIG 4A indicates how the intake air pulsation pressure changed with respect to the crank angle while the four-cylinder engine incorporating the intake manifold of the first example embodiment is running at 3500 rpm, and FIG 4B indicates how the intake air pulsation pressure changed with respect to the crank angle while the four-cylinder engine incorporating the intake manifold not having the partitions 14a to 14c is running at 3500 rpm.
[0026] Referring to FIG 4B, in the case of the engine having the intake manifold with no partitions, which is a comparative example, the maximum value of the intake air pulsation pressure in the latter stage of the intake stroke of the second cylinder #2 is much smaller than the maximum value of the intake air pulsation pressure in the latter stage of the intake pressure of the first cylinder #1. This indicates that a portion of the intake air flowing into the manifold branch opening 13b for the second cylinder #2 flows back and into the manifold branch opening 13a for the first cylinder #1 at the moment the intake stroke of the second cylinder #2 and the intake stroke of the first cylinder #1 partially overlap during the time period corresponding to the latter stage of the intake stroke of the second cylinder #2 and the initial stage of the intake stroke of the first cylinder #1. Likewise, the maximum value of the intake air pulsation pressure in the latter stage of the intake stroke of the third cylinder #3 is much smaller than the maximum value of the intake air pulsation pressure in the latter stage of the intake pressure of the fourth cylinder #4. This indicates that a portion of the intake air flowing into the manifold branch opening 13c for the third cylinder #3 flows back and into the manifold branch opening 13d for the fourth cylinder #4 at the moment the intake stroke of the third cylinder #3 and the intake stroke of the fourth cylinder #4 partially overlap during the time period corresponding to the latter stage of the intake stroke of the third cylinder #3 and the initial stage of the intake stroke of the fourth cylinder #4.
[0027] On the other hand, in the case of the engine incorporating the intake manifold of the first example embodiment, referring to FIG. 4A, the maximum value of the intake air pulsation pressure of the second cylinder #2 in the latter stage of its intake stroke is substantially equal to the maximum value of the intake air pulsation pressure of the first cylinder #1 in the latter stage of its intake stroke, and likewise, the maximum value of the intake air pulsation pressure of the third cylinder #3 in the latter stage of its intake stroke is substantially equal to the maximum value of the intake air pulsation pressure of the fourth cylinder #4 in the latter stage of its intake stroke. This indicates that the use of the intake manifold of the first example embodiment prevents a portion of the intake air flowing into one of the manifold branch openings for the respective cylinders from being drawn into the other of the manifold branch openings as mentioned above.
[0028] FIG 5 illustrates the variation of the volumetric efficiency of a four-cylinder engine incorporating the intake manifold of the first example embodiment with respect to the engine speed in comparison with the same volumetric efficiency variation of a four-cylinder engine incorporating an intake manifold with no partitions. In FIG 5, the variation of the volumetric efficiency of the four-cylinder engine incorporating the intake manifold of the first example embodiment is indicated by the solid sequential line and the variation of the volumetric efficiency of the four-cylinder engine incorporating the intake manifold with no partitions is indicated by the single-dotted sequential line.
[0029] Referring to FIG 5, the volumetric efficiency of the engine incorporating the intake manifold of the first example embodiment is lower than the volumetric efficiency of the engine incorporating the intake manifold with no partitions in the engine speed ranges near 2750 rpm and 5250 rpm, but is higher than the volumetric efficiency of the engine incorporating the intake manifold with no partitions in other engine speed ranges. This makes it clear that the use of the intake manifold of the first example embodiment reliably suppresses the reduction of the volumetric efficiency due to the above-described intake stroke time overlapping.
[0030] In the intake manifold of the first example embodiment, as described above, the partition 14a is provided on the bottom face of the surge tank 11 at the position between the manifold branch opening 13a for the first cylinder #1 and the manifold branch opening 13b for the second cylinder #2 and the partition 14b is provided on the bottom face of the surge tank 11 at the position between the manifold branch opening 13c for the third cylinder #3 and the manifold branch opening 13d for the fourth cylinder #4. This structure reliably suppresses the intake air backflows between the manifold branch openings for the two cylinders that are fired consecutively, that is, between the manifold branch opening 13c for the third cylinder #3 and the manifold branch opening 13d for the fourth cylinder #4, and the manifold branch opening 13b for the second cylinder #2 and the manifold branch opening 13a for the first cylinder #1. Further, because the partition 14a and the partition 14b are connected to each other via the partition 14c, the effect of suppressing the intake air backflows is enhanced.
[0031] The structure of the intake manifold of the first example embodiment may be modified in various forms as in the following examples. FIG 6 shows the first modification example of the intake manifold of the first example embodiment.
[0032] Referring to FIG 6, in this modification example, partitions 114a, 114b are formed on the bottom face of the surge tank 11 in place of the partitions 14a to 14c. The partition 114a is formed generally in the shape of the letter "L" having an extension portion that extends toward the side of the manifold branch opening 13b for the second cylinder #2 from the end of the partition 114a on the side where intake air flows into the surge tank 11, and likewise, the partition 114b is formed generally in the shape of the letter "L" having an extension portion that extends toward the side of the manifold branch opening 13c for the third cylinder #3 from the end of the partition 114b on the side where intake air flows into the surge tank 11. This partition arrangement provides effects that are the same as or similar to those obtained in the first example embodiment.
[0033] FIG 7 shows the second modification example of the intake manifold of the first example embodiment. In this modification example, as shown in FIG 7, only the partitions 14a, 14b among the partitions 14a to 14c of the intake manifold of the first example embodiment are provided on the bottom face of the surge tank 11. This structure also provides effects that are the same as or similar to those obtained in the first example embodiment if the height of each partition 14a, 14b and the intake air distribution are appropriately set. [0034] Next, an intake manifold for a multi-cylinder engine according to the second example embodiment of the invention will be described with reference to FIG 8 and FIG 9. This intake manifold is incorporated in a four-cylinder engine as in the first example embodiment. The intake manifold of the second example embodiment is particularly different from the intake manifold of the first example embodiment in that the intake manifold of the second example embodiment is configured to suppress the intake air backflows between the manifold branch opening 13a for the first cylinder #1 and the manifold branch opening 13c for the third cylinder #3 and between the manifold branch opening 13d for the fourth cylinder #4 and the manifold branch opening 13b for the second cylinder #2. Hereinafter, the intake manifold of the second example embodiment will be described with focus on the differences from the intake manifold of the first example embodiment. Note that the appearance of the intake manifold of the second example embodiment is the same as that of the intake manifold of the first example embodiment shown in FIG 1 and FIG 2.
[0035] FIG 8 corresponds FIG 3, schematically showing the structure of the portion of the intake manifold where the surge tank 11 is formed as viewed from above. As shown in FIG 8, in the intake manifold of the second example embodiment, a partition 214 is provided on the bottom face of the surge tank 11 at a position between the manifold branch opening 13b for the second cylinder #2 and the manifold branch opening 13c for the third cylinder #3. This arrangement of the partition 214 suppresses the intake air backflows between the manifold branch opening 13a and the manifold branch opening 13c and between the manifold branch opening 13b and the manifold branch opening 13d.
[0036] FIG 9 illustrates the variation of the volumetric efficiency of the four-cylinder engine incorporating the intake manifold of the second example embodiment with respect to the engine speed in comparison with the same volumetric efficiency variation of a four-cylinder engine incorporating an intake manifold with no partitions. In FIG 9, the variation of the volumetric efficiency of the four-cylinder engine incorporating the intake manifold of the second example embodiment is indicated by the solid sequential line, the variation of the volumetric efficiency of the four-cylinder engine incorporating the intake manifold with no partitions is indicated by the single-dotted sequential line, and the variation of the volumetric efficiency of the four-cylinder engine incorporating the intake manifold of the first example embodiment is indicated by the double-dotted sequential line.
[0037] As shown in FIG 9, the volumetric efficiency of the engine incorporating the intake manifold of the second example embodiment is lower than the volumetric efficiency of the engine incorporating the intake manifold with no partitions in, for example, the engine speed range near 5250 rpm, but is higher than the volumetric efficiency of the engine incorporating the intake manifold with no partitions in other engine speed ranges. Further, the volumetric efficiency of the engine incorporating the intake manifold of the second example embodiment is just slightly lower than the volumetric efficiency of the engine incorporating the intake manifold of the first example embodiment in the speed ranges other than those near 2750 rpm and 4500 rpm. Thus, as in the case of the intake manifold of the first example embodiment, when the intake manifold of the second example embodiment is used, the reduction of the volumetric efficiency is suppressed as compared to when the intake manifold with no partitions is used.
[0038] According to the intake manifold of the second example embodiment, as described above, because the partition 214 is provided on the bottom face of the surge tank 11 at the position between the manifold branch opening 13b for the second cylinder #2 and the manifold branch opening 13c for the third cylinder #3, the intake air backflows are effectively suppressed between the manifold branch opening 13a for the first cylinder #1 and the manifold branch opening 13c for the third cylinder #3 and the manifold branch opening 13d for the fourth cylinder #4 and the manifold branch opening 13b for the second cylinder #2.
[0039] There are also four-cylinder engines in which ignition is performed in the order of the first cylinder #1, the third cylinder #3, the second cylinder #2, and the fourth cylinder #4. In such four-cylinder engines, too, by incorporating the principal of the intake manifold of the first example embodiment, the intake air backflows can be reliably suppressed between the manifold branch opening 13b for the second cylinder #2 and the manifold branch opening 13c for the third cylinder #3.
[0040] The intake manifold of the second example embodiment can by modified in various forms as in the following examples. FIG 10 shows the first modification example of the intake manifold of the second example embodiment.
[0041] Referring to FIG. 10, in this modification example, a partition 314 is provided on the bottom face of the surge tank 11 in place of the partition 214 of the second example embodiment. The partition 314 is formed generally in the shape of the letter "T" having two extension portions, one extending toward the side of the manifold branch opening 13b for the second cylinder #2 from the end of the partition 314 on the side where intake air flows into the surge tank 11 and the other extending toward the side of the manifold branch opening 13c for the third cylinder #3 from the same end of the partition 314. According to this structure, the intake air backflows can be more reliably suppressed between the respective manifold branch openings.
[0042] FIG 11 shows the second modification example of the intake manifold of the second example embodiment. Referring to FIG 11, in the second modification example, a partition 414 is provided on the bottom face of the surge tank 11 in place of the partition 214 of the intake manifold of the second example embodiment. The partition 414 is formed generally in the shape of the letter "Y" having two extension portions, one extending toward the side of the manifold branch opening 13b for the second cylinder #2 from the end of the partition 314 on the side where intake air flows into the surge tank 11 and the other extending toward the side of the manifold branch opening 13c for the third cylinder #3 from the same end of the partition 314. According to this structure, the intake air backflows can be more reliably suppressed between the respective manifold branch openings.
[0043] Next, intake manifolds for a multi-cylinder engine according to other example embodiments of the invention will be described with reference to FIG 12 and FIG 13. Each of these intake manifolds is incorporated in a four-cylinder engine as in the foregoing example embodiments. In the example embodiment illustrated in FIG. 12, partitions 514a to 514c are provided on the bottom face of the surge tank 11. More specifically, referring to FIG 12, on the bottom face of the surge tank 11, the partition 514a is provided between the manifold branch opening 13a for the first cylinder #1 and the manifold branch opening 13b for the second cylinder #2, the partition 514b is provided between the manifold branch opening 13c for the third cylinder #3 and the manifold branch opening 13d for the fourth cylinder #4, and the partition 514c is provided between the manifold branch opening 13b for the second cylinder #2 for the second cylinder #2 and the manifold branch opening 13c for the third cylinder #3. This arrangement of the partitions 514a to 514c provides synergistic effects of the first example embodiment (more specifically, the first modification example of the first example embodiment) and the second example embodiment.
[0044] On the other hand, in the example embodiment illustrated in FIG 13, partitions 514a to 514d are provided on the bottom face of the surge tank 11. Referring to FIG 13, in this example embodiment, the partition 514d is provided on the bottom face of the surge tank 11 in addition to the partitions 514a to 514c shown in FIG 12, such that the end of the partition 514a on the side where intake air flows into the surge tank 11 and the end of the partition 514b on the same side are connected to each other via the partition 514d. According to this structure, the intake air backflows can be more reliably suppressed between the manifold branch openings.
[0045] As well as the structures employed in the foregoing example embodiments, various other structures may be incorporated. For example, the partitions 514a, 514b of the intake manifold shown in FIG 12 may be replaced by the partitions 114a, 114b shown in FIG 6. The partition 514c of the intake manifold shown in FIG 12 may be replaced by the partition 314 shown in FIG 10. Further, the partition 514c of the intake manifold shown in FIG 12 may be replaced by the partition 414 shown in FIG 11.
[0046] In all the foregoing example embodiments described above, preferably, each partition extends to a side face of the surge tank 11. According to this structure, the intake air backflows can be more reliably suppressed between the manifold branch openings.
[0047] While the invention has been embodied as an intake manifold for a four-cylinder engine irt the foregoing example embodiments, it may be embodied as an intake manifold for a multi-cylinder engine having a different number of cylinders, such as a six-cylinder engine. That is, an intake manifold according to the invention may be embodied in various forms with at least one partition being formed upright on the bottom face of the surge tank at a position between two or more manifold branch openings so as to suppress the intake air backflow between the manifold branch openings.
[0048] While the invention has been described with reference to example embodiments thereof, it is to be understood that the invention is not limited to the example embodiments or constructions. To the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the example embodiments are shown in various combinations and configurations, which are example, other combinations and configurations, including more, less or only a single element, are also within the spirit and scope of the invention.

Claims

1. An intake manifold for a multi-cylinder engine, having a surge tank (11) connected to an intake passage of the multi-cylinder engine and a plurality of manifold branches (20a to 2Od) extending from manifold branch openings (13a to 13d) provided in an inner face of the surge tank (11) to intake ports of the multi-cylinder engine, characterised by comprising: at least one partition (14a to 14c, 114a, 114b, 214, 314, 414, 514a to 514d) that is provided on the inner face of the surge tank (11) at a position- between the manifold branch openings (13a to 13d).
2. The intake manifold according to claim 1, wherein assuming that the inner face of the surge tank (11) is the bottom face of the surge tank (11), the end of partition (14a to 14c, 114a, 114b, 214, 314, 414, 514a to 514d) extends to a side face of the surge tank (11).
3. The intake manifold according to claim 2, wherein assuming that the inner face of the surge tank (11) is the bottom face of the surge tank (11), the end of partition (14a to 14c, 114a, 114b, 214, 314, 414, 514a to 514d) on the side opposite from where intake air flows into the surge tank (11) extends to a side face of the surge tank (11).
4. The intake manifold according to any one of claims 1 to 3, wherein the multi-cylinder engine is a four-cylinder engine having a first cylinder, a second cylinder, a third cylinder, and a fourth cylinder that are arranged in numeric order from one side to the other side of the multi-cylinder engine, and one of the partitions (14a) is provided between the manifold branch opening (13a) for the first cylinder and the manifold branch opening (13b) for the second cylinder and the other of the partitions (14b) is provided between the manifold branch opening (13c) for the third cylinder and the manifold branch opening (13d) for the fourth cylinder.
5. The intake manifold according to claim 4, wherein the end of one of the partitions (14a) on the side where intake air flows into the surge tank (11) and the end of the other of the partitions (14b) on the side where intake air flows into the surge tank (11) are connected to each other.
6. The intake manifold according to claim 4, wherein one of the partitions (114a) is formed generally in the shape of the letter "L" having an extension portion that extends toward the side of the manifold branch opening (13b) for the second cylinder from the end of the same partition (114a) on the side where intake air flows into the surge tank (11), and the other of the partitions (114b) is formed generally in the shape of the letter "L" having an extension portion that extends toward the side of the manifold branch opening (13c) for the third cylinder from the end of the same partition (114b) on the side where intake air flows into the surge tank (11).
7. The intake manifold according to any one of claims 1 to 3, wherein the multi-cylinder engine is a four-cylinder engine having a first cylinder, a second cylinder, a third cylinder, and a fourth cylinder that are arranged in numeric order from one side to the other side of the multi-cylinder engine, and the partition (214) is provided between the manifold branch opening (13b) for the second cylinder and the manifold branch opening (13c) for the third cylinder.
8. The intake manifold according to claim 7, wherein the partition (314) is formed generally in the shape of the letter "T" having an extension portion that extends toward the side of the manifold branch opening (13b) for the second cylinder from the end of the partition (314) on the side where intake air flows into the surge tank (11) and another extension portion that extends toward the side of the manifold branch opening (13c) for the third cylinder from the same end of the partition (314).
9. The intake manifold according to claim 7, wherein the partition (414) is formed generally in the shape of the letter "Y" having an extension portion that extends toward the side of the manifold branch opening (13b) for the second cylinder from the end of the partition (414) on the side where intake air flows into the surge tank (11) and another extension portion that extends toward the side of the manifold branch opening (13c) for the third cylinder from the same end of the partition (414). (
10. The intake manifold according to any one of claims 1 to 3, wherein the multi-cylinder engine is a four-cylinder engine having a first cylinder, a second cylinder, a third cylinder, and a fourth cylinder that are arranged in numeric order from one side to the other side of the multi-cylinder engine, and a first one of the partitions (514a) is provided between the manifold branch opening (13a) for the first cylinder and the manifold branch opening (13b) for the second cylinder, a second one of the partitions (514b) is provided between the manifold branch opening (13c) for the third cylinder and the manifold branch opening (13d) for the fourth cylinder, and a third one of the partitions (514b) is provided between the manifold branch opening (13b) for the second cylinder and the manifold branch opening (13c) for the third cylinder.
11. The intake manifold according to claim 10, wherein
> an end of the partition (514a) provided between the manifold branch opening (13a) for the first cylinder and the manifold branch opening (13b) for the second cylinder and an end of the partition (514b) provided between the manifold branch opening (13c) for the third cylinder and the manifold branch opening (13d) for the fourth cylinder are connected to each other, the connected ends of the partitions (13a, 13b) being located on the side where intake air flows into the surge tank (11).
12. The intake manifold according to any one of claims 1 to 11, wherein assuming that the inner face of the surge tank (11) is the bottom face of the surge tank (11), the height of the partition (14a to 14c, 114a, 114b, 214, 314, 414, 514a to 514d) is lower than the height of a side face of the surge tank (11).
13. The intake manifold according to claim 12, wherein the height of the partition (14a to 14c, 114a, 114b, 214, 314, 414, 514a to 514d) is approximately one-fourth the diameter of each of the manifold branch openings (13a to 13d).
PCT/IB2007/003410 2006-11-09 2007-11-08 Intake manifold for multi-cylinder engine WO2008056240A2 (en)

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JP2006-304290 2006-11-09
JP2006304290A JP2008121469A (en) 2006-11-09 2006-11-09 Intake manifold for multi-cylinder engine

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WO2008056240A3 WO2008056240A3 (en) 2008-08-14

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102013019026A1 (en) * 2013-11-13 2015-05-13 Daimler Ag Charge air housing for a motor vehicle engine

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5077775B2 (en) * 2009-02-18 2012-11-21 株式会社デンソー High pressure pump
JP7540388B2 (en) 2021-04-20 2024-08-27 トヨタ紡織株式会社 Intake manifold

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60173363A (en) * 1984-02-17 1985-09-06 Nissan Motor Co Ltd Suction pipe for internal-combustion engine
JPS60222524A (en) * 1984-04-19 1985-11-07 Mazda Motor Corp Suction device of engine
JPH01300047A (en) * 1988-05-25 1989-12-04 Suzuki Motor Co Ltd Air cleaner for multicylinder engine
JPH02207133A (en) * 1989-02-03 1990-08-16 Honda Motor Co Ltd Suction device for internal combustion engine
JPH03189321A (en) * 1989-12-18 1991-08-19 Mazda Motor Corp Intake device of engine
US5704326A (en) * 1992-12-10 1998-01-06 Hitachi, Ltd. Air induction system for internal-combustion engine
JP2003074428A (en) * 2001-09-03 2003-03-12 Honda Motor Co Ltd Intake device for multicylinder internal combustion engine
US20030111036A1 (en) * 2001-12-19 2003-06-19 Aisan Kogyo Kabushiki Kaisha Vehicle intake manifolds
FR2868132A1 (en) * 2004-03-26 2005-09-30 Mann & Hummel Gmbh Air supply installation for internal combustion engine, has air collector comprising air guide installation that extends until half of admission tube so that half of tube is covered by guide installation
WO2005119044A1 (en) * 2004-06-01 2005-12-15 Stephen Wessels Fluid distribution manifold

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60173363A (en) * 1984-02-17 1985-09-06 Nissan Motor Co Ltd Suction pipe for internal-combustion engine
JPS60222524A (en) * 1984-04-19 1985-11-07 Mazda Motor Corp Suction device of engine
JPH01300047A (en) * 1988-05-25 1989-12-04 Suzuki Motor Co Ltd Air cleaner for multicylinder engine
JPH02207133A (en) * 1989-02-03 1990-08-16 Honda Motor Co Ltd Suction device for internal combustion engine
JPH03189321A (en) * 1989-12-18 1991-08-19 Mazda Motor Corp Intake device of engine
US5704326A (en) * 1992-12-10 1998-01-06 Hitachi, Ltd. Air induction system for internal-combustion engine
JP2003074428A (en) * 2001-09-03 2003-03-12 Honda Motor Co Ltd Intake device for multicylinder internal combustion engine
US20030111036A1 (en) * 2001-12-19 2003-06-19 Aisan Kogyo Kabushiki Kaisha Vehicle intake manifolds
FR2868132A1 (en) * 2004-03-26 2005-09-30 Mann & Hummel Gmbh Air supply installation for internal combustion engine, has air collector comprising air guide installation that extends until half of admission tube so that half of tube is covered by guide installation
WO2005119044A1 (en) * 2004-06-01 2005-12-15 Stephen Wessels Fluid distribution manifold

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102013019026A1 (en) * 2013-11-13 2015-05-13 Daimler Ag Charge air housing for a motor vehicle engine

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