JPWO2013146703A1 - Intake device for internal combustion engine - Google Patents

Abstract

In an intake device for an internal combustion engine, a throttle valve (22) and an intake distribution valve (61) are provided in an intake passage (P). The downstream side of the intake distribution valve (61) is partitioned into an upper intake passage (Up) and a lower intake passage (Lp) by a partition plate (60). The intake air distribution valve (61) is pivotally attached to a position (61a) in the vicinity of the upstream end edge of the partition plate (60) and extends in the upstream direction. The ratio of the intake air flowing through the upper intake passage (Up) and the lower intake passage (Lp) is changed. The amount of intake air flowing through the upper and lower passages can be selectively distributed according to the load state, and the combustion efficiency is optimized by adjusting the strength of the tumble vortex.

Description

  The present invention relates to an intake device for an internal combustion engine mounted on a vehicle.

  In order to improve fuel efficiency in the low load region of an internal combustion engine, tumble is generated in the intake air taken in the combustion chamber, and fuel is sent around the ignition plug at the upper part of the combustion chamber to stratify the combustion efficiency. Inhalation devices are known.

  In this intake device, the intake port and the exhaust port extend from the intake valve port and the exhaust valve port on the ceiling surface of the combustion chamber of the cylinder head while curving in a direction away from each other, and the intake port guides the intake chamber to the combustion chamber. Among them, the intake air sucked into the combustion chamber from the inner edge side close to the cylinder axis of the intake valve port (the central axis of the cylinder bore) flows down toward the exhaust side and then moves down the exhaust side of the cylinder bore along the piston top surface. By bending the flow and raising the intake side, a vertical vortex, so-called tumble, is formed.

  Therefore, in order to increase the rate of intake air that is drawn from the inner edge near the cylinder axis of the intake valve port, the interior of the intake port is partitioned into upper and lower passages by a partition wall, and the lower passage is opened and closed upstream of the partition wall. An intake control valve is provided to close the lower passage immediately after engine startup, so that intake air flowing through the passage above the intake port is drawn into the combustion chamber from the inner edge side of the intake valve port, which is an extension of the upper passage. In this way, an intake device that generates a strong vortex tumble has been proposed (see Patent Document 1).

JP 2008-151078 A

In the intake device described in Patent Literature 1, the intake control valve provided on the upstream side of the partition wall of the intake port is pivotable with the shaft portion at the base end pivotally attached to the lower wall of the intake port. By turning the intake control valve around the shaft and lying down along the inner surface of the lower wall, the upstream opening of the lower passage opens, intake air flows through both the upper and lower passages, and the intake control valve By rotating upward so that the leading edge thereof contacts the upstream edge of the partition wall, the upstream opening of the lower passage is closed, and intake air flows only through the upper passage.
Therefore, immediately after the engine is started, the intake control valve closes the upstream opening of the lower passage, and the intake air flows through the upper passage and enters the combustion chamber, thereby generating a strong vortex tumble and increasing the combustion efficiency.

In the medium load region of the internal combustion engine, if the tumble vortex is too strong, reduction of fuel consumption is hindered by rapid combustion, and cranking noise may be generated due to rapid combustion.
Therefore, in the middle load region, it is desired to suppress the intake air flowing through the passage above the intake port. However, in the intake control by the intake control valve described in Patent Document 1, only the upstream opening of the upper passage is partially limited. It is impossible to suppress the intake air flowing in the upper passage by closing.

The present invention has been made in view of the above points, and the purpose of the present invention is to make it possible to selectively distribute the intake air amount flowing in the upper and lower passages according to the load state and to adjust the strength of the vortex flow of the tumble. An intake device for an internal combustion engine that can optimize the combustion efficiency is provided.
Another object of the present invention is to generate a strong vortex tumble in the low load region, suppress the occurrence of tumble in the medium load region, and maximize the cylinder intake air amount in the high load region. It is the point which provides the intake device of the internal combustion engine which can aim at the optimization of combustion efficiency by adjusting the intensity | strength of the vortex | eddy_current of a tumble according to a load state.

  In order to achieve the above object, according to the present invention, a combustion chamber is configured between a top surface of a piston slidably fitted in a cylinder bore of a cylinder block and a ceiling surface of the cylinder head opposed to the top surface. The intake port and the exhaust port that are opened in the ceiling surface of the cylinder head are formed to extend while curving in a direction away from each other, and an inlet pipe is connected to the intake port to continuously The intake pipe is provided with a throttle valve and an intake distribution valve downstream of the intake pipe, and the intake passage is partially downstream of the intake distribution valve and partially separated from the upper intake passage by a partition plate. The intake air is divided into side intake passages, the intake air flowing through the upper intake passage and the lower intake passage is controlled by the intake air distribution valve, and the intake air distribution means controls the intake air distribution passage. In the intake device of the internal combustion engine in which the valve is driven and controlled, the intake distribution valve is provided adjacent to the upstream end edge of the partition plate, and distributes intake air downstream from the throttle valve up and down and the upper intake passage and the Provided is an intake device for an internal combustion engine, wherein the ratio of intake air flowing through a lower intake passage is changed.

  According to a preferred embodiment of the present invention, the intake divergence valve has a proximal end pivotally attached to the inlet pipe at a position adjacent to the upstream end edge of the partition plate, and a distal end facing the upstream side of the intake is vertically moved. The flap valve is swingable.

  In a preferred embodiment of the present invention, a passage sectional area of the upper intake passage is smaller than a passage sectional area of the lower intake passage.

  Preferably, the downstream end of the partition plate is located in the intake port and adjacent to the intake valve stem.

  According to a preferred embodiment of the present invention, the intake valve port and the exhaust valve port face the combustion chamber one at a position opposite to each other with respect to the cylinder axis that is the central axis of the cylinder bore on the ceiling surface of the cylinder head. And the intake valve port is formed so as to be offset so as to have a crescent-shaped protrusion protruding outward from the circular hole of the cylinder bore as viewed in the cylinder axial direction.

  In the intake system for an internal combustion engine according to the present invention, the intake control means sets the intake distribution valve to a low load position so that when the internal combustion engine is in a low load state, the intake air is largely distributed upward and flows through the upper intake passage. In the middle load state, the intake valve is positioned at the middle load position so as to suppress the intake air flowing through the upper intake passage by allocating the intake air from the lower part to the lower part. Operates so as to position the intake air distribution valve at a high load position so as to distribute the intake air up and down in proportion to the partition plate.

  A preferred embodiment of the present invention includes an upper injector and a lower injector for injecting fuel in the upper intake passage and the lower intake passage of the inlet pipe, respectively, and the upper intake passage according to the swing state of the intake distribution valve. The injection amounts of the injector and the lower injector are controlled.

  According to the intake device for an internal combustion engine of the present invention, the intake distribution valve is provided adjacent to the upstream end edge of the partition plate, and distributes the intake air downstream from the throttle valve up and down to provide the upper intake passage and the lower intake passage. Since the ratio of the intake air flowing is changed, the intake air amount flowing in the upper and lower passages can be appropriately and selectively distributed according to the load state, and the combustion efficiency can be optimized by adjusting the strength of the tumble vortex.

  The intake divergence valve is a flap valve whose base end is pivotally supported by the inlet pipe at a position adjacent to the upstream end edge of the partition plate, and whose tip toward the intake upstream side is swingable up and down. The ratio of distributing intake air up and down can be easily changed by the swing position of the tip of the valve.

  Since the passage cross-sectional area of the upper intake passage is smaller than the passage cross-sectional area of the lower intake passage, the intake air passes through a narrow upper intake passage in a low load state and is sucked into the combustion chamber. It is possible to improve the combustion efficiency by generating vortex tumble.

  Since the downstream end of the partition plate is located in the intake port and in the vicinity of the intake valve stem, the intake air passing through the upper intake passage can be guided to the vicinity of the intake valve port in a low load state. The tumble can be easily generated.

  An intake valve port formed on the ceiling surface of the cylinder head is offset so as to have a crescent-shaped protruding portion protruding outward from the circular hole of the cylinder bore as viewed in the cylinder axial direction. The ratio of the opening perimeter of the protruding portion to the entire opening perimeter of the intake can be secured large, and intake from the outer edge side (the protruding portion side) of the intake valve port to the combustion chamber is hindered from the inner edge side of the intake valve port. By suppressing the occurrence of reverse tumble that suppresses the tumble generated by inhalation, it is possible to promote the generation of a strong vortex tumble.

  When the internal combustion engine is in a low load state, the intake control means can form a strong vortex tumble by positioning the intake distribution valve at a low load position so that most of the intake air is distributed upward and flows through the upper intake passage. In the middle load state, the intake air distribution valve is positioned at the middle load position so as to suppress the intake air flowing through the upper intake passage by lowering the ratio of the intake air from the lower part to the upper part of the intake passage, thereby suppressing the tumble vortex as much as possible and preventing rapid combustion. In high load conditions, the intake valve is positioned at a high load position so that intake air is divided up and down in the proportion divided by the partition plate, so that a sufficient amount of intake air flows through the upper intake passage. It can generate tumble and maintain good intake efficiency, and can optimize the combustion efficiency by adjusting the strength of the tumble vortex according to the load condition of the internal combustion engine, Costs can be reduced.

  An upper injector and a lower injector for performing fuel injection are respectively provided in the upper intake passage and the lower intake passage of the inlet pipe, and the injection amounts of the upper injector and the lower injector are controlled according to the swing state of the intake distribution valve. This makes it possible to further improve the combustion efficiency and optimize the air-fuel ratio by optimally controlling the injection amounts of the upper and lower injectors according to the swinging state of the intake distribution valve, that is, the vertical distribution state of the intake flow rate. Can do.

1 is a right side view of a motorcycle equipped with an internal combustion engine including an intake device according to an embodiment of the present invention. It is a partial cross section right side sectional view of the internal combustion engine. It is a top view of a cylinder block. It is a bottom view of a cylinder head. It is expansion explanatory drawing of the ceiling surface of a combustion chamber. It is principal part sectional drawing of the internal combustion engine in a low load state. It is principal part sectional drawing of the internal combustion engine in a medium load state. It is principal part sectional drawing of the internal combustion engine in a high load state. It is the IX-IX sectional view taken on the line of FIG. It is the XX sectional view taken on the line of FIG. It is a graph which shows the control of the intake distribution valve opening degree (phi) with respect to throttle opening (theta), and the change of the tumble ratio Rt. It is principal part sectional drawing of an internal combustion engine provided with the intake device which concerns on another embodiment. It is the XIII-XIII sectional view taken on the line of FIG. 13 is a graph showing control of an intake distribution valve opening φ and a fuel injection ratio r with respect to a throttle opening θ in the embodiment of FIG.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 is an overall side view of a motorcycle 1 equipped with an internal combustion engine 10 equipped with an intake device according to the present embodiment.

The body frame 2 of the motorcycle 1 has a pair of left and right main frame pipes 2b and 2b extending backward from the head pipe 2a. The main frame pipes 2b and 2b are bent downward after extending backward. Steeply inclined portions 2ba and 2ba are formed. The lower portions of the steeply inclined portions 2ba and 2ba are bent forward and reach the lower end.
In addition, a pair of left and right down frame pipes 2c, 2c are extended substantially parallel to the steeply inclined portion 2ba of the main frame pipe 2b in a side view when viewed from the side.

  The seat rails 2d, 2d extend rearward from the upper portions of the steeply inclined portions 2ba, 2ba of the main frame pipes 2b, 2b, and connect the central portion of the seat rails 2d, 2d and the lower portions of the steeply inclined portions 2ba, 2ba. Backstays 2e and 2e support seat rails 2d and 2d.

In the vehicle body frame 2 as described above, the front fork 3 is pivotally supported on the head pipe 2a, the front wheel 4 is pivotally supported at the lower end thereof, and the pivot plate 2f is fixed to the lower front part of the main frame pipes 2b and 2b. A rear fork 5 pivotally supported at the front end of the pivot plate 2f extends rearward, and a rear wheel 6 is pivotally supported at the rear end thereof. A cushion 7 is interposed.
A fuel tank 8 is installed on the main frame pipes 2b and 2b, and a seat 9 is supported behind the fuel tank 8 by seat rails 2d and 2d.

  The internal combustion engine 10 mounted on the vehicle body frame 2 is an SOHC type two-valve single-cylinder four-stroke internal combustion engine. The crankshaft 12 (FIG. 2) is oriented in the vehicle body width direction with respect to the vehicle body, and the cylinder is slightly tilted forward. Suspended in a standing posture.

  As shown in FIG. 2, in a crankcase 11 that rotatably supports the crankshaft 12 of the internal combustion engine 10, a transmission gear is provided between a main shaft 13 and a countershaft 14 that are disposed behind the crankshaft 12. A mechanism 15 is arranged. The counter shaft 14 is an output shaft, and a chain (not shown) is bridged between the counter shaft 14 and the rotating shaft of the rear wheel 6, and power is transmitted from the output shaft to the rear wheel 6 through the chain.

Referring to FIG. 2, a cylinder block 16 in which a cast iron cylinder liner 16L is cast is mounted on a crankcase 11, and a cylinder head 17 is mounted on the cylinder block 16 via a gasket. The cylinder block 16 and the cylinder head 17 are integrally fastened by stud bolts, and the cylinder head cover 18 covers the cylinder head 17 above.
The cylinder block 16, the cylinder head 17, and the cylinder head cover 18 stacked on the crankcase 11 extend upward from the crankcase 11 in a slightly tilted posture (see FIGS. 1 and 2).

  In this way, the inlet pipe 20 extends through the connecting pipe 19 from the cylinder head 16 which is erected with the internal combustion engine 10 mounted on the vehicle body frame slightly inclined forward, and the inlet pipe 20 includes a throttle valve. A butterfly-type throttle body 21 incorporating 22 is provided, an injector 23 is mounted, and an intake air distribution valve 61 described later is further provided.

As shown in FIG. 1, an air cleaner 24 connected to the rear end of the inlet pipe 20 is disposed in a space surrounded by the steeply inclined portion 2ba, the seat rail 2d, and the backstay 2e of the main frame 2b in a side view. (See FIG. 1).
Further, the exhaust pipe 27 extending forward from the cylinder head 17 is bent downward and further bent rearward, and is arranged rearward along the lower surface of the crankcase 11 and on the right side of the rear wheel 6 toward the right side. It is connected to the muffler 26.

  Referring to FIG. 2, crankcase 11 is divided into left and right crankcase halves, and the lower end of cylinder liner 16L is fitted into an opening formed in the mating surface of the left and right crankcase halves. It projects slightly upward and protrudes upward. A piston 25 is slidably fitted in a cylinder bore 16b inside the cylinder liner 16L, and a connecting rod 26 is connected between a piston pin 25p of the piston 25 and a crank pin 12p of the crankshaft 12 to provide a crank mechanism. Is configured.

A combustion chamber 40 is formed between the top surface 25t of the piston 25 sliding in the cylinder bore 16b of the cylinder block 16 and the ceiling surface 41 of the cylinder head 17 facing the same top surface 25t.
The cylinder head 17 has an intake valve port 42 and an exhaust valve port 43 (FIGS. 4 and 6) on the ceiling surface 41 one at a position opposite to each other in the diametrical direction with respect to the cylinder axis C that is the central axis of the cylinder bore 16 b. The intake port 44 and the exhaust port 45 are formed so as to be curved and extend in directions away from each other from the intake valve port 42 and the exhaust valve port 43, respectively.

In FIG. 2, the intake port 44 extends from the intake valve port 42 to the rear of the motorcycle, communicates with the inlet pipe 20 through the connection pipe 19, and the exhaust port 45 is connected to the exhaust pipe 27 (FIG. 1).
An intake valve 46 and an exhaust valve 47 that are slidably supported by valve guides 34i and 34e fitted integrally with the cylinder head 16 are driven by a valve mechanism 30 provided on the cylinder head 13, The intake valve port 42 of the intake port 44 and the exhaust valve port 43 of the exhaust port 45 are opened and closed in synchronization with the rotation of the crankshaft 12.

  The valve operating mechanism 30 is a valve operating mechanism of an SOHC type internal combustion engine in which one camshaft 31 is axially supported on the cylinder head 17 in the left-right direction. The rocker arm shafts 32e and 32i are supported diagonally forward and backward of the cam shaft 31, the intake rocker arm 33i is pivotally supported by the rear rocker arm shaft 32i, and the exhaust rocker arm 33e is rockable by the front rocker arm shaft 32e. Is supported at the center.

  One end of the intake rocker arm 33i is in contact with the intake cam lobe of the cam shaft 31, the other end is in contact with the upper end of the valve stem 46s of the intake valve 46 biased by a spring via an adjustment screw, and one end of the exhaust rocker arm 33e is The exhaust cam lobe of the shaft 31 is in contact with the upper end of the valve stem 47s of the exhaust valve 47 biased by a spring via an adjusting screw, and the intake rocker arm 33i and the exhaust rocker arm 33e are swung by the rotation of the cam shaft 31. Then, the intake valve 46 and the exhaust valve 47 are opened and closed.

FIG. 3 is a top view of the cylinder block 16. A circular hole of the cylinder bore 16b and a rectangular hole of the chain chamber 16c through which a chain for transmitting power to the valve mechanism 30 is inserted in the mating surface 16f with the cylinder head 17. Has been.
FIG. 4 is a bottom view of the cylinder head 17 superimposed on the cylinder block 16. The ceiling surface 41 of the combustion chamber 40 is recessed in the mating surface 17f facing the mating surface 16f of the cylinder block 16 corresponding to the cylinder bore 16b. In addition, a chain chamber 17c communicating with the chain chamber 16c is formed.

A circular opening edge 41s of the ceiling surface 41 of the combustion chamber 40 at the mating surface 17f of the cylinder head 17 coincides with the circular hole of the cylinder bore 16b.
A large-diameter intake valve port 42 is opened on the rear side of the ceiling surface 41, and an exhaust valve port 43 that is somewhat smaller in diameter than the intake valve port 42 is opened on the front side of the ceiling surface 41.
The ceiling surface 41 is provided with a plug hole 48 through which a spark plug (not shown) protrudes.

  FIG. 5 is a view of the combustion chamber 40 of the cylinder head 17 as viewed in the axial direction of the cylinder axis C, that is, as viewed in the cylinder axial direction. With reference to FIG. A portion of the periphery of the intake valve port protrudes outward from the circular ceiling surface opening edge 41s corresponding to the circular hole of the cylinder bore 16b of the 40 ceiling surface 41, and the intake valve port 42 is offset. It has a crescent-shaped protruding portion 42a protruding from the ceiling surface opening edge 41s (the portion indicated by the dotted points in FIG. 5).

  When the ratio of the opening circumferential length of the protruding portion 42a to the entire opening circumferential length of the opening edge 42s of the intake valve port 42 is a masking rate Rm, the masking rate Rm due to the offset of the intake valve port 42 is about 20 to 50%.

  Referring to FIG. 5, the ceiling surface 41 is formed with a dome-shaped recess 51 having an elliptical cross-sectional shape surrounding the intake valve port 42 and the exhaust valve port 43 on both sides in the major axis direction. Squishes 52 and 52 are formed in a pair of right and left crescent-shaped portions outside the dome-shaped recess 51 in the ceiling surface 41, respectively.

  A pair of guide wall surfaces 53, 53 curved around the opening edge 42 s of the intake valve port 42 from both ends of the crescent protrusion 42 a of the intake valve port 42 around the outer periphery of the intake valve port 42, Opposite to each other, they are formed so as to gradually expand toward the exhaust valve port 43 side.

  With respect to the ceiling surface 41 of the combustion chamber 40 of the cylinder head 17 formed as described above, the cylinder bore 16b of the cylinder block 16 has a cylinder bore 16b as shown in FIG. 3, FIG. 6, FIG. 7, and FIG. A notch in which the rear side portion of the opening edge on the head 17 side facing the protruding portion 42a of the intake valve port 42 is cut out in the moving direction of the intake valve 46 to the maximum valve lift position along the periphery of the ridge portion 46p of the intake valve 46 A circular curved surface 55 is formed.

  As shown in FIGS. 7, 8, and 9, the cut-out circular curved surface 55 covers the upper end surface of the flangeless cylinder liner 16L of the aluminum alloy cylinder block 16 in which the cast iron cylinder liner 16L is cast. It is formed by notching diagonally at the part.

  Since the peripheral edge of the cap portion 46p of the intake valve 46 moves along the notched circular curved surface 55 and close to the notched circular curved surface 55, the intake valve port 42 is opened while the intake valve 46 is opened and moved to the maximum valve lift position. The intake air from the outer edge side (the protruding portion 42a side) of the intake valve 46 must pass through a very narrow gap between the peripheral edge of the umbrella portion 46p of the intake valve 46 and the notched circular curved surface 55, and the intake into the combustion chamber 40 is almost hindered and masked. It is in the state that was done.

Therefore, masking is performed from the outer edge side of the intake valve port 42 and intake air is only slightly sucked into the combustion chamber 40, and suction is mainly performed from the inner edge side of the intake valve port 42. The structure is easy to generate.
It should be noted that the maximum valve lift position of the intake valve 46 may be at a position slightly beyond the notched circular curved surface 55.

  As shown in FIG. 6, the portion of the peripheral surface of the top surface 25t of the piston 25 that faces the protruding portion 42a of the intake valve port 42 is cut away in parallel with the outer peripheral end surface of the cap portion 46pf of the intake valve 46. A notch surface 56 is formed (see FIG. 6). When the intake valve 46 opens and lifts as the piston 25 descends during the intake stroke, the intake inflow direction from the outer edge side of the intake valve port 42 and the piston cut-off Since the notch surface (56) is vertical, intake of intake air is not urged from the outer edge side of the intake valve port 42 to the combustion chamber 40, and the occurrence of reverse tumble is further suppressed.

  In the intake system, the intake passage P extending from the inlet pipe 20 to the intake port 44 via the connecting pipe 19 is separated from the upper intake passage Up by the partition plate 60 from the downstream portion of the inlet pipe 20 to the curved portion of the intake port 44. A side intake passage Lp is partitioned.

The partition plate 60 is formed integrally with the inlet pipe 20, the upstream end portion of the partition plate 60 is provided on the inside of the inlet pipe 20 so as to partition the top and bottom, and the extended portion that protrudes greatly downstream is the intake port 44. Has been inserted.
As shown in FIG. 9, the strip-like extended portion of the partition plate 60 has both side edges extending along the inner peripheral surface of the intake port 44.
The partition plate 60 approaches the intake passage P upward, and the passage sectional area of the upper intake passage Up is smaller than the passage sectional area of the lower intake passage Lp (see FIG. 9).

  The long extension portion of the partition plate 60 is bent along the curved shape of the intake port 44, and the downstream end portion 60e at the tip is an intake valve located at the curved portion of the intake port 44 as shown in FIG. 46, the downstream end portion 60 e is formed with a recessed portion 60 u that is recessed in a U shape from the leading edge, and the intake valve stem 46 s passes through the U-shaped recessed portion 60 u. .

  The downstream end 60e is a flat plate that is not curved, and is linearly inserted into the curved portion of the intake port 44. The left and right sides of the downstream end 60e face the curved portion of the intake port 44 from side to side. The left and right concave grooves 44v and 44v are inserted and fixedly supported.

In the inlet pipe 20, an intake distribution valve 61 is provided downstream of the throttle valve 22 and upstream of the partition plate 60.
Referring to FIGS. 6, 7, and 8, in the intake distribution valve 61, the rotation shaft 61 a at the base end is pivotally supported by the inlet pipe 20 in the vicinity of the upstream end edge of the partition plate 60 and directed toward the intake upstream side. A flap valve whose tip can be swung up and down is swung by a motor drive mechanism 62.

  The intake divide valve 61 swings with the tip toward the upstream throttle valve 22, and distributes the intake air downstream from the throttle valve 22 up and down to change the proportion of intake air flowing through the upper intake passage Up and the lower intake passage Lp. can do.

  An ECU (electronic control unit) 65 (FIG. 2) that controls the internal combustion engine 10 includes intake control means 66, which analyzes the operating state of the internal combustion engine 10 and uses the intake control means 66 to control the throttle valve 21 of the intake system. While the injector 23 is driven and controlled, the intake distribution valve 61 is also driven and controlled by the intake control means 66.

Referring to FIG. 6, the throttle opening θ of the throttle valve 22 is a fully open state when it is rotated from the fully closed state and becomes parallel to the intake passage, and indicates a load state of the internal combustion engine 10.
The intake distribution valve 61 is controlled to swing according to the load state of the internal combustion engine 10, and the intake distribution valve opening φ, which is the swing angle of the intake distribution valve 61, is the intake distribution in the low load state shown in FIG. The swing angle increases clockwise in FIG. 6 with the low load position of the valve 61 as the reference 0 degree.

The tumble state can be represented by a tumble ratio Rt which is the number of rotations of the tumble per revolution of the crankshaft 12.
Tumble ratio Rt = Tumble rotation angular velocity / Crankshaft angular velocity If the tumble ratio Rt is large, a strong vortex tumble is generated.

FIG. 11 shows a change in the intake distribution valve opening φ and a change in the tumble ratio Rt for swing control of the intake distribution valve 61 according to the throttle opening θ.
Hereinafter, the swing control of the intake distribution valve 61 according to the load state of the internal combustion engine 10 and the tumble ratio Rt will be considered with reference to FIG.

  When the internal combustion engine 10 is in a low load operation state, as shown in FIG. 6, the throttle valve 22 is opened small (throttle opening θ: small), and the intake distributing valve 61 has a leading edge below the intake passage P. Since it is positioned at a low load position (intake distribution valve opening φ = 0 °) in contact with the peripheral surface, the intake distribution valve 61 distributes the intake air mostly upward, and the intake air flows through the upper intake passage Up.

  Accordingly, the intake air that has passed through the slightly opened opening of the throttle valve 22 is guided to the relatively narrow upper intake passage Up by the intake air distribution valve 61 and flows at a high speed, and the intake port 44 is curved. Because the partition plate 60 extending to the intake valve stem 46s located in the section is guided to the vicinity of the intake valve port 42, most of the intake air is discharged from the inner edge side (cylinder axis C side) of the intake valve port 42 to the combustion chamber 40. As shown in FIG. 6, a strong vortex tumble is generated (the tumble ratio Rt is increased).

  The intake valve port 42 is offset so as to have a crescent-shaped protruding portion 42a protruding outward from the circular hole of the cylinder bore 16b in the cylinder axial direction, and the outer edge side (the protruding portion 42a side) of the intake valve port 42 is masked. In addition, since there is almost no intake air passing through the lower intake passage Lp, there is no intake air to be sucked into the combustion chamber 40 from the outer edge side of the intake valve port 42, no reverse tumble that prevents tumble is generated, and tumble is generated more strongly. The tumble ratio Rt becomes high, and the combustion efficiency at low load can be improved.

When the internal combustion engine 10 is in a medium load operation state, as shown in FIG. 7, the throttle valve 21 opens to a medium opening (throttle opening θ: medium), and the intake distribution valve 61 has a leading edge above the intake passage P. It is positioned at a medium load position (intake distribution valve opening φ = β degrees) approaching the circumferential surface. For this reason, the intake distribution valve 61 distributes the intake air in a smaller proportion from the lower side to the upper side.
Accordingly, as indicated by the arrows in FIG. 7, sufficient intake air flows through the lower intake passage Lp, but intake air flowing through the upper intake passage Up is suppressed.

  Therefore, even if the suppressed intake air flowing through the upper intake passage Up enters the combustion chamber 40 from the inner edge side of the intake valve port 42, the suppressed intake air is weak and therefore only a weak vortex tumble is generated. There is some intake air that is sucked into the combustion chamber 40 from the outer edge side of the 42 and a reverse tumble is generated to suppress the tumble. Therefore, the tumble is suppressed as much as possible, and the tumble ratio Rt is reduced.

  When the internal combustion engine 10 is in a high load operation state, as shown in FIG. 8, the throttle valve 21 is fully open (throttle opening θ: fully open), and the intake distribution valve 61 is a high load position that is flush with the partition plate 60. (Intake distribution valve opening φ = α degrees). For this reason, the intake air distribution valve 61 distributes the intake air up and down to the ratio of the intake air divided by the partition plate (60).

  Therefore, as indicated by arrows in FIG. 8, sufficient intake air flows through the upper intake passage Up and the lower intake passage Lp, and the intake air that has flowed through the upper intake passage Up enters the combustion chamber 40 from the inner edge side of the intake valve port 42. The intake air that has been inhaled to generate a tumble and flows through the lower intake passage Lp enters the combustion chamber 40 from the outer edge side of the intake valve port 42 while being masked, and causes some reverse tumble, but from the upper intake passage Up Since a sufficient amount of intake air is inhaled, a moderate vortex tumble with a relatively high tumble ratio Rt can be generated, and the intake efficiency can be well maintained by sufficient intake.

  As described above, the intake device of the internal combustion engine 10 can optimize the combustion efficiency by adjusting the strength of the tumble vortex according to the load state of the internal combustion engine.

  This intake divide valve 61 is a flap valve in which a pivot shaft 61a at the base end is pivotally supported by the inlet pipe 20 in the vicinity of the upstream end edge of the partition plate 60, and the tip toward the intake upstream side is swingable up and down. Therefore, the ratio of the intake air to be vertically distributed can be easily changed depending on the swing position of the tip.

In the intake device according to the above-described embodiment, the injector 23 is mounted only on the upper intake passage Up of the upper intake passage Up and the lower intake passage Lp that are vertically divided by the partition plate 60, but the lower intake passage Lp An embodiment in which an injector is also mounted is shown in FIGS.
An upper injector 71 is attached to the upper intake passage Up, and a lower injector 72 is attached to the lower intake passage Lp. Other members are the same as those in the above embodiment, and the same reference numerals are used.

FIG. 14 shows the fuel injection ratio r (lower injection amount / upper injection amount) between the upper injector 71 and the lower injector 72.
As the throttle opening θ increases, the intake distribution valve opening φ is simply increased from 0 degree in the low load state to α degree in the high load state.

In a low load state, that is, when intake air flows only through the upper intake passage Up, the fuel injection ratio r is 0%, and the lower injector 72 does not inject fuel and only the upper injector 71 injects fuel.
When the throttle opening θ increases and the load increases, the fuel injection amount of the lower injector 72 increases as the intake distribution valve opening φ increases and the ratio of the intake air flowing through the lower intake passage Lp to the upper intake passage Up increases. The fuel injection ratio r is increased.
In a high load state, the fuel injection ratio r is made substantially equal to the ratio of the partition plate 60 that partitions the intake passage P up and down (the ratio of the intake air flowing through the lower intake passage Lp with respect to the upper intake passage Up).

  As described above, the injection amount (fuel injection ratio r) of the upper injector 71 and the lower injector 72 is optimally controlled according to the swinging state of the intake distribution valve 61, that is, the intake flow upward / downward distribution state (intake distribution valve opening φ). As a result, the combustion efficiency can be further improved and the air-fuel ratio (A / F) can be optimized.

DESCRIPTION OF SYMBOLS 1 ... Motorcycle, 2 ... Body frame, 10 ... Internal combustion engine, 11 ... Crankcase, 12 ... Crankshaft, 13 ... Main shaft, 14 ... Countershaft, 16 ... Cylinder block, 16b ... Cylinder bore, 17 ... Cylinder head, 18 ... Cylinder head cover, 19 ... Connecting pipe,
20 ... Inlet pipe, 21 ... Throttle body, 22 ... Throttle valve, 23 ... Injector, 24 ... Air cleaner, 25 ... Piston, 26 ... Connecting rod,
30 ... Valve mechanism, 31 ... Cam shaft, 32e, 32i ... Rocker arm shaft, 33i ... Intake rocker arm, 33e ... Exhaust rocker arm, 34i, 34e ... Valve guide,
40 ... Combustion chamber, 41 ... Ceiling surface, 42 ... Intake valve port, 42a ... Projection part, 43 ... Exhaust valve port, 44 ... Intake port, 45 ... Exhaust port, 46 ... Intake valve, 46pf ... Bulk part, 46s ... Intake Valve stem, 47 ... exhaust valve, 48 ... plug hole,
51 ... Dome-shaped recess, 52 ... Squish, 53 ... Guide wall, 55 ... Notched circular surface, 56 ... Piston notched surface,
60 ... partition plate, 61 ... intake distribution valve, 62 ... motor drive mechanism, 65 ... ECU, 66 ... intake control means, 71 ... upper injector, 72 ... lower injector.
Up: upper intake passage, Lp: lower intake passage, P: intake passage.

Claims (7)

Combustion between the top surface of the piston (25) slidably fitted in the cylinder bore (16b) of the cylinder block (16) and the ceiling surface (41) of the cylinder head (17) facing the top surface Chamber (40) is constructed,
While the intake port (44) and the exhaust port (45) are curved away from each other from the intake valve port (42) and the exhaust valve port (43) opened on the ceiling surface (41) of the cylinder head (17), Formed to extend,
An inlet pipe (20) is connected to the intake port (44) to form a continuous intake passage (P),
The inlet pipe (20) is provided with a throttle valve (22) and an intake distribution valve (61) downstream thereof,
The intake passage (P) is partially divided into an upper intake passage (Up) and a lower intake passage (Lp) by a partition plate (60) downstream from the intake distribution valve (61), and the intake distribution valve ( 61) controls the intake air flowing through the upper intake passage (Up) and the lower intake passage (Lp),
In the intake device of the internal combustion engine in which the intake distribution valve (61) is drive-controlled by the intake control means (66),
The intake air distribution valve (61) is provided adjacent to the upstream edge of the partition plate (60), and distributes intake air downstream from the throttle valve (22) up and down, and the upper intake passage (Up) and the lower intake passage (Up). An intake device for an internal combustion engine, wherein a ratio of intake air flowing through the side intake passage (Lp) is changed.   The intake divide valve (61) is pivotally mounted on the inlet pipe (20) at a position adjacent to the upstream end edge of the partition plate (60) and swings the tip toward the intake upstream side up and down. 2. An intake device for an internal combustion engine according to claim 1, wherein the flap valve is a free flap valve.   The intake device for an internal combustion engine according to claim 1 or 2, wherein a passage sectional area of the upper intake passage (Up) is smaller than a passage sectional area of the lower intake passage (Lp).   The downstream end (60e) of the partition plate (60) is located in the intake port (44) and adjacent to the intake valve stem (46s). An intake device for an internal combustion engine according to any one of the preceding claims. The intake valve port (42) and the exhaust valve port (43) are arranged on the ceiling surface (41) of the cylinder head (17) one at a position opposite to each other with respect to the cylinder axis (C) which is the central axis of the cylinder bore (16b). ) Is opened facing the combustion chamber (40), and the intake valve port (42) has a crescent-shaped protrusion (42a) protruding outward from the circular hole of the cylinder bore (16b) in the cylinder axial direction. The intake device for an internal combustion engine according to any one of claims 1 to 4, wherein the intake device is formed by being offset.   The intake air control means (66) positions the intake air distribution valve (61) at a low load position so that when the internal combustion engine is in a low load state, the intake air is largely distributed upward and flows through the upper intake passage (Up). In the middle load state, the intake distribution valve (61) is positioned at the medium load position so as to suppress the intake air flowing through the upper intake passage (Up) by allocating the intake air from the lower part to the lower part. 6. The internal combustion engine according to claim 5, wherein the intake air distribution valve (61) is positioned at a high load position so as to distribute the intake air up and down in a ratio divided by the partition plate (60) in a load state. Inhalation device. The upper intake passage (Up) and the lower intake passage (Lp) of the inlet pipe (20) includes an upper injector (71) and a lower injector (72) for performing fuel injection, respectively.
The intake control means (66) controls an injection amount of the upper injector (71) and the lower injector (72) according to a swinging state of the intake distribution valve (61). The intake device for an internal combustion engine according to any one of claims 1 to 6.

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