JP3244908B2 - Engine intake control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake control system for an engine, and more particularly to an engine intake control device provided with a tumble generation variable means for generating a tumble in an intake flow introduced into a cylinder in accordance with an operation state of the engine. The present invention relates to an improvement in an intake control method capable of securing a required intake air amount even in a low-speed rotation range.

[0002]

2. Description of the Related Art It is known that it is effective to generate a vertical vortex, so-called tumble, in an intake air introduced into a cylinder in order to improve a combustion state of an engine, particularly in a low speed rotation range. As a means for generating the tumble, conventionally, for example, a method in which intake air is biased toward the top wall side of the intake passage to direct the intake air into the cylinder from the vicinity of the cylinder axis in the axial direction and to introduce the intake air into the cylinder (For example, see Japanese Patent Application No. 3-111185).

[0003]

The above-mentioned tumble generating means is constructed so as to generate the above-mentioned tumble by reducing the intake passage area by some means, especially in a low-speed rotation range of the engine. Therefore,
There is a tendency that the inflow resistance of the intake air flow becomes high and the amount of intake air tends to be insufficient. As a result, there is a concern that the combustion state can be improved but the output becomes lower than the designed value.

The present invention has been made in view of such circumstances, and provides an engine intake control device capable of improving a combustion state by generating a tumble and securing a required amount of air. It is intended to be.

[0005]

According to the first aspect of the present invention, there are provided a long passage and a short passage which are independent of each cylinder connected to an intake passage connected to an intake valve opening of each cylinder; An air inlet at each upstream end of the short passage is opened in the surge tank, a throttle valve is disposed at the air inlet to the surge tank, and a vertical vortex (hereinafter referred to as a tumble) flowing into the cylinder in the cylinder axial direction. ) And a non-tumble state in which a positive change is generated and a non-tumble state is generated in an inactive manner, and the short passage is opened and closed by a passage length switching valve to reduce the length of the intake passage. An intake passage length changing means for changing the length of the intake passage to a long side; andintake control means for changing the passage length to a long side when the tumble generation changing means is switched to a tumble state. It is an intake control device for an engine according to claim.

According to a second aspect of the present invention, in the first aspect, the tumble generation variable means adjusts a non-tumble position in which the intake passage is fully opened and a tumble is inactively generated, and an intake flow is a top wall of the intake passage. A tumble switching valve that pivots between a tumble position that positively generates a tumble by flowing to the side, and the intake control means,
In the low-speed rotation range of the engine, the tumble switching valve is rotated to a tumble position and the passage length switching valve is rotated to a closed position.

[0007] The invention of claim 3 is another specific example of each component in the invention of claim 1. First, this engine has the following configuration. The intake passage has three intake valve openings, and the intake passage is defined by a partition wall as a first passage connected to the two intake valve openings and a second passage connected to the remaining one intake valve opening. One intake valve opening is formed to direct intake air in the cylinder axial direction. Further, a long passage and a short passage are connected to a junction of the first and second passages.

Further, the tumble generation variable means includes a tumble switching valve for opening and closing the second passage. Furthermore, the intake passage length varying means includes a passage length switching valve for opening and closing the short passage. The intake control means is configured to rotate the tumble switching valve and the passage length switching valve to a closed position in a low-speed rotation range of the engine.

In the present invention, changing the length of the intake passage means that it is suitable for obtaining a so-called inertia supercharging effect, that is, changing the length of the intake passage according to the engine speed. The terms “shake” and “short” mean the intake passage length at which an inertial supercharging effect is obtained in a low-medium-speed rotation range and a high-speed rotation range of the engine, respectively.

In the present invention, inactive generation of tumble does not mean that tumble is not generated at all. For example, the flow of intake air is not controlled by turning the tumble switching valve. This means that a tumble to a degree caused by the shape of the intake port is generated.

[0011]

According to the intake control apparatus for an engine according to the present invention, when the tumble generation variable means is controlled to the tumble state, for example, in a low-speed rotation range of the engine, the intake control means sets the intake path length variable means to be long at the same time. Control the state.

For example, in the third aspect of the present invention, the tumble switching valve rotates to the tumble position, the intake air flows toward the ceiling wall side, is introduced into the cylinder from the intake valve opening in the axial direction, and is tumbled. Occurs. In the invention of claim 2,
A tumble switching valve closes the second passage, and intake air flows only through the first passage, and at least a portion of the intake air flows in an axial direction into the cylinder from an intake valve opening shaped to generate tumble on the first passage. The tumble is generated. In this case, in any case, the tumble switching valve is controlled to the tumble state, and at the same time, the intake passage length switching valve closes the short passage. Introduced through the passage.

Therefore, according to the present invention, when the tumble generating means is in a tumble generating state by, for example, reducing the area of the intake passage in a low-speed rotation range of the engine, the intake passage length varying means closes the short passage and the intake air is supplied at a low speed. It is introduced through a long passage that provides an inertial supercharging effect in the rotation range. As a result, a tumble is generated, the combustion state is improved, and a required intake air amount is obtained by inertia supercharging, and a required output is secured.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 10 are views for explaining an intake control device for a V-type engine according to an embodiment (first embodiment) of the first and second aspects of the present invention, and FIG. 1 is a schematic front view of the engine of the present embodiment. 2, FIG. 2 is a sectional front view of the apparatus of the embodiment, FIG. 3 is a plan view of the engine of the embodiment, FIG. 4 is a sectional view taken along line IV-IV of FIG. 3, FIG. 5 is a bottom view of the intake system, and FIG. FIG. 7 is a plan view of a tank portion, FIG. 7 is a plan view of a tumble switching valve, FIGS.
FIG. 3 is a schematic diagram for explaining the operation of the device of the present embodiment.

In the figure, 1 is a water-cooled 4-cycle V-type 8
The engine 1 is an engine 1 in which an oil pan 3 forming a lower portion of a crank chamber is coupled to a lower mating surface of a skirt portion 2a forming an upper portion of a crank chamber of a cylinder block 2,
The left and right cylinder heads 4 and 5 are connected to the mating surfaces of the left and right cylinder portions 2b and 2c forming the V bank of the cylinder block 2 with head bolts.
5 has left and right head covers 6 and 7 mounted on the upper mating surface. The engine of this embodiment includes left and right cylinder units 2b and 2c, left and right cylinder heads 4 and 5,
Since the left and right head covers 6 and 7 and the valve mechanisms disposed inside are symmetrical left and right, the following description and illustration will be made only for either the left or right.

Four cylinder bores (cylinders) 2d are formed in each of the cylinder portions 2b and 2c in parallel with each other, and a piston 8 slidably inserted into each of the cylinder bores 2d is connected via a connecting rod 9. It is connected to the crankshaft 10.

Each of the left and right cylinder heads 4, 5 is provided with four combustion recesses 11 which form combustion chambers on the block side mating surfaces 4a, 5a.
In FIG. 1, three intake valve openings 11a to 11c and two exhaust valve openings 11d and 11e are formed. The exhaust valve openings 11d and 11e are opened and closed by an exhaust valve 12, and the exhaust valves 12 are opened and closed by an exhaust cam shaft 13. The intake valve openings 11a, 11b, 11c are opened and closed by intake valves 14a, 14b, 14a, respectively.
The intake cam shaft 15 is driven by the intake cam shaft 15 to open and close.

Each of the exhaust valve openings 11d and 11e is led out to the bank outer wall of each of the cylinder heads 4 and 5 by one exhaust port 16, and an exhaust manifold 17 is provided at an external connection opening 16a of each of the exhaust ports 16. It is connected.

The intake valve openings 11a to 11c are led out through the intake ports 18 to the inner side walls of the banks of the cylinder heads 4 and 5, respectively. An intake unit 19 is connected to the external connection opening 18a of the intake port 18. The intake unit 19 includes the left and right cylinder portions 2b and 2c,
The shape is set so as to fill the V bank space A formed by the left and right cylinder heads 4 and 5 and the left and right head covers 6 and 7. The intake unit 19 includes left and right valve bodies 20 connected to the external connection opening 18a.
a, 20b and an intake manifold 21 arranged in an arched manner between the two valve bodies 20a, 20b.
And a surge tank 22 suspended below the intake manifold 21.

The connection surfaces of the external connection openings 18a of the left and right cylinder heads 4 and 5 are formed flush and parallel to the crankshaft.
b has a flat plate shape. This left and right valve body 2
0a and 20b, 1 extends parallel to the crankshaft 10.
A tumble switching valve 23 in which one valve plate 23b is fixed to each cylinder is disposed on the valve shaft 23a. The valve plate 23b is formed with a notch 23c located outside the V bank when the valve plate 23b is turned to the fully closed position. Therefore, when the intake port 18 is closed by the valve plate 23b, the intake air flows toward the top wall 18b side of the intake port 18 and is introduced from the center of the cylinder in the axial direction, so that tumble is easily generated. I have.

A fuel injection valve 24 is mounted on each of the valve bodies 20a and 20b so as to be substantially vertical, one for each cylinder.
3 and the intake camshaft 15. Each of the fuel injection valves 24 is located substantially on the center line of the intake port 18 when viewed from a plane, and its fuel injection port is directed to each of the intake valve openings 11a to 11c.

In this embodiment, the following configuration is employed in order to more reliably generate the tumble.
The axis P of the ignition plug 41 is inclined outward by an angle θ3 with respect to the cylinder axis H to the outside of the bank, and the intake valves 14a,
14b is raised on the cylinder axis H side as compared to the exhaust valve 12, and a space is secured inside the bank for forming the intake port more vertically. The intake valves 14a,
The distance from the cylinder axis H to the exhaust camshaft 13 is L1 while the distance from the cylinder axis H to the intake camshaft 15 is small as L2 due to the upright position of 14b. The intake port 18 is formed so as to rise as much as possible on the cylinder axis H side, and the notch 23c of the tumble switching valve 23 is located on the top wall 18b side. As a result, the intake air flow that is biased toward the top wall 18b due to the closing of the tumble switching valve 23 is more strongly directed from the vicinity of the cylinder center toward the cylinder axis H, and the tumble is reliably generated. Further, the fuel from the fuel injection valve 24 is injected so as to intersect with the skewed intake air flow, thereby improving the mixing of the air and the fuel.

The intake manifold 21 has a merging passage 21a connected to the valve body 20a or 20b.
Is extended obliquely inward and upward in the V bank space A, and the long passage 21b is extended downward by bending the long passage 21b from the upper end of the merging passage 21a.
It has a structure in which a short passage 21c having a larger cross-sectional area and a shorter length is branched.

The lower end opening 21d of the long passage 21b is provided.
A long tube 25 is provided at the lower end opening 21 of the short passage 21c.
A short pipe 26 is connected to each of e. The long tube 25 and the short tube 26 extend downward in the surge tank 22, and lower end openings 25 a, 26 of the two tubes 25, 26 are provided.
a is expanded in a trumpet shape and is directed toward the side wall 22a of the surge tank 22 on the cylinder side. This allows
Each short tube 21c can be arranged in the crankshaft direction without any gap (see FIG. 4), and the opening 26a of the adjacent short tube 26 is provided.
The short tube 26 can be made large in diameter without causing interference between them.

Further, the length of the passage on the long side is approximately twice as long as the length of the passage on the short side due to the above-mentioned structure. Further, the lower end openings 25a, 26a of the two tubes 25, 26 and the side wall are formed. A relatively large space B is formed between the space B and the space 22a. Thereby, the flow of air in the crankshaft direction in the surge tank 22 is improved. The long tube 25 and the short tube 26 are desirably made of resin or pipe in order to reduce the weight.

The long passage 21 of the intake manifold 21
b and the lower end opening 21 of the merging passage 21a
f is flush with the end face of the short passage 21c.
The end face of the lower end opening 21e is
d, 21f are located above the lower end surface. This is to avoid interference between the drive actuator of the passage length switching valve and the throttle valve, as described later.

All the short passages 21c are positioned so as to overlap on a straight line parallel to the crankshaft, and one valve shaft 27a is provided in the short passage 21c.
And an intake passage length switching valve 2 in which one valve plate 27b is fixed to the valve shaft 27a for each cylinder.
7 are provided. The valve shaft 27a is parallel to the valve shaft 23a of the left and right tumble switching valves 23 described above.

The length measured along the passage axis from the opening 26a of the short passage 26 to each of the intake valve openings 11a to 11c is, for example, a length at which the inertia supercharging effect is obtained in a high-speed rotation range of 4600 rpm or more. Is set to
The length measured along the axis of the passage from the opening 25a of the long passage 25 to each of the intake valve openings 11a to 11c is, for example, a length at which an inertial supercharging effect is obtained in a low-speed rotation region of less than 4600 rpm. Is set.

The surge tank 22 has a bowl-like shape with a transverse cross section bulging downward, and has a connection flange 22b having an upper end opening.
To the lower end openings 21d and 21f of the intake manifold 21.
It is sealed by connecting to a mating surface formed flush with the above. An air inlet 22c is formed at one end in the crankshaft direction of the surge tank 22, and a throttle body 30b is provided at the air inlet 22c with a pair of valve plates 30a rotatably arranged in a throttle body 30b. Valve 30
Is connected.

Here, the intake air is introduced into the surge tank from the air inlet 22c, and is sucked into the engine from the long pipe 25 and the short pipe 26 through the intake manifold 21. In a multi-cylinder engine such as that described above, the air inlet 22c
Is provided, there is a possibility that the intake air amount varies. Therefore, in the present embodiment, as shown in FIG. 5, the long pipe 25 'at a position away from the air inlet 22c is opened toward the upstream with respect to the air flow, and the position near the air inlet 22c is increased. The long tube 25 ″ is opened toward the downstream side. This suppresses imbalance in the amount of air. Further, since the long tubes 25 ', 25 "are obliquely disposed to achieve the above object, as shown in FIG. 4, the height of these long tubes 25'(25" is not shown) is increased. As a result, the front and rear corner portions 22 ′ of the surge tank 22 can be reduced, and the arrangement space as a whole can be reduced.

A diaphragm valve 28 as an actuator is provided at an outwardly protruding end of the valve shaft 27a of the intake passage length switching valve 27, and an output shaft of the diaphragm valve 28 is connected to the valve shaft 27a. ing. The diaphragm valve 28 is supported by a boss 21g of the intake manifold 21, which is the same member as the one on which the intake passage length switching valve 27 is provided, and the diaphragm 29 is provided with the tumble switching valve 23. It is supported by valve bodies 20a and 20b which are the same members as those provided. Therefore, it is possible to avoid the occurrence of an assembly error between each switching valve and the diaphragm valve, and it is possible to smoothly perform the opening and closing operation.

As described above, the intake passage length switching valve 27
Is disposed higher than the tumble switching valve 23, thereby avoiding interference with the throttle body 30 disposed on the same side as the intake passage length switching valve 27.

Next, the function and effect of this embodiment will be described. In FIG. 8, reference numeral 40 denotes an ECU for controlling the opening and closing of the tumble switch 23, the intake passage length switching valve 27, the throttle valve 30a, and the like. This indicates an engine operating state such as the throttle valve opening a and the engine speed b. A signal is input, and the tumble switching signal A and the passage length switching signal B are output according to the operating state of the engine.

First, as shown in FIG. 8, in the low-speed low-load operation range in which the engine speed is, for example, 2600 rpm or less and the throttle opening is, for example, about 10%, the tumble switching valve 23 of the diaphragm valve 29 is set in the tumble state. Switching signal A is supplied, whereby the tumble switching valve 23 is rotated to the tumble position, that is, the closed position (only the position shown in FIG. 2) in which only the top wall side of the intake passage 18 is open. As a result, the intake air flows toward the top wall side of the intake passage 18 and is introduced in the axial direction from the vicinity of the cylinder shaft to generate a tumble. In this case, as described above, the intake port 18 is formed upright so as to be closer to the cylinder axis H side by the inclined arrangement of the spark plug 41 and the intake valves 14a and 14b, and the notch 23c is located on the top wall 18b side. Therefore, occurrence of tumble is more reliable.

At this time, the diaphragm valve 28 is supplied with a switching signal B for making the passage length switching valve 27 longer so that the passage length switching valve 27 becomes shorter as shown in FIG. The passage 21c is closed, and the intake air is introduced from the long pipe 25 into the cylinder through the long passage 21b. As a result, the intake passage length is such that an inertial supercharging effect can be obtained in the low-speed rotation range, and a sufficient intake amount can be secured while generating the above-mentioned tumble.

As shown in FIG. 9, when the engine speed is, for example, 2600-4600 rpm and the throttle opening is, for example, about 40%, a medium-speed rotation medium load range, the tumble switching valve 23 is fully opened, that is, in the non-tumble position. On the other hand, the passage length switching valve 27 keeps the passage length in a long state.
As a result, the throttle for generating tumble is released, and a larger amount of intake air is secured.

Further, as shown in FIG. 10, in the high-speed and high-load operation range where the engine speed is, for example, 4600 rpm or more and the throttle opening is substantially fully open, the passage length switching valve 27 opens the short passage 21c. Is introduced into the cylinder through a short passage having a length that provides an inertial supercharging effect in the high-speed rotation region, and the remainder is introduced into the cylinder through the long passage, so that a large amount of intake air is secured in the high-speed rotation region.

As described above, in this embodiment, when the tumble switching valve 23 is rotated to the tumble position in the low-speed rotation range to generate a tumble, the passage length switching valve 27 is switched to the long side to thereby reduce the inertia. Since the supercharging effect is obtained, the reduction in intake air volume due to the inflow resistance caused by the generation of tumble can be compensated for by inertial supercharging. And a decrease in output can be avoided.

In this embodiment, each of the switching valves 23, 27,
Since the three valve shafts 23a, 27a, 23a are arranged in parallel with the crankshaft, many passages can be opened and closed by one switching valve, and the structure can be simplified. In this case, the intake passage length switching valve 27 located at the center of the V bank
Since the valve shaft 27a is disposed above the valve shafts 23a of the other two switching valves 23, the throttle body 30
Can be avoided.

FIGS. 11 to 13 are schematic diagrams for explaining an intake control device according to an embodiment (second embodiment) of the first and third aspects of the present invention. In the present embodiment, the intake valve opening 1
An intake port 18 that leads 1a to 11c to the inner wall of the bank of each cylinder head 4, 5 is provided with a first intake port 18a connected to the intake valve openings 11a and 11b by a partition wall 18d.
And a second intake port 18 connected to the intake valve opening 11c.
b.

Here, of the intake valve openings 11a to 11c, the opening 11b located at the center is set in a so-called tumble port shape. That is, as shown in FIG. 2, the cylinder shaft H is supplied to the intake air taken into the cylinder bore.
In order to generate a tumble by setting the direction, the angle θ1 between the axis V1 of the intake valve opening 11b (which coincides with the axis of the intake valve 14b) and the cylinder axis H is set to, for example,
The axis of the right intake valve opening 11a, 11c (the intake valve 14a,
The shape is set smaller than the angle θ2 formed between V2 and the cylinder axis H (which coincides with the axis of 14c), that is, the shape is more oriented in the cylinder axis direction.

In the valve bodies 20a and 20b,
A partition wall 20 continuous with a partition wall 18d of the intake port 18 is provided in a merging passage 21a of the intake manifold 21.
c, 21h are formed. The above valve body 2
0a and 20b, 1 extends parallel to the crankshaft 10.
A tumble switching valve 23 in which one valve plate 23b is fixed to each cylinder is disposed on the valve shaft 23a. The valve plate 23b is located on the second intake port 18b side,
When the second intake port 18b is closed by the valve plate 23b, the intake air flows only through the first intake port 18a.

In the second embodiment, as shown in FIG. 11, in the low-speed rotation and low-load operation range, the second intake port 18b is fully closed by the tumble switching valve 23, and the intake air is supplied only to the first intake port 18a. As a result, the air is introduced into the cylinder from the intake valve opening 11a and the tumble port 11b in the axial direction, and tumble occurs. In the middle-speed rotation middle-load operation range and the high-speed rotation high-load operation range, the tumble switching valve 23 is fully opened, and the intake air passes through both the first and second intake ports 18a and 18b. It is almost the same.

[0044]

As described above, according to the engine intake control apparatus of the present invention, when the tumble generation variable means is in the tumble state, the intake passage length variable means is simultaneously in the long state. For example, in the invention of claim 2, when the tumble switching valve rotates to the tumble position, the intake passage length switching valve closes the short passage, and in the invention of claim 3, when the tumble switching valve closes the second passage, the intake passage length changes. A switching valve closes the short passage. Therefore, in the present invention, when the tumble generating means is in a tumble generating state by narrowing the intake passage area or the like in a low-speed rotation region of the engine, the intake passage length varying means closes the short passage, and the intake air in the low-speed rotation region. It is introduced through a long passage that provides an inertial supercharging effect. As a result, a tumble is generated, the combustion state is improved, and a required intake air amount is obtained by inertial supercharging, so that a required output is secured.

[Brief description of the drawings]

FIG. 1 is a first embodiment of the invention according to claims 1 and 2 (first embodiment);
1 is a front view of an engine including an intake control device according to the first embodiment.

FIG. 2 is a sectional front view of the engine of the first embodiment.

FIG. 3 is a plan view of the engine of the first embodiment.

FIG. 4 is a cross-sectional side view of the engine of the first embodiment (shown in FIG. 3).
IV-IV section).

FIG. 5 is a bottom view of the intake manifold of the engine of the first embodiment.

FIG. 6 is a plan view of a surge tank portion of the engine of the first embodiment.

FIG. 7 is a front view of the tumble switching valve of the first embodiment.

FIG. 8 is a schematic diagram for explaining the operation of the engine of the first embodiment.

FIG. 9 is a schematic diagram for explaining the operation of the engine of the first embodiment.

FIG. 10 is a schematic diagram for explaining the operation of the engine of the first embodiment.

FIG. 11 is a schematic diagram for explaining an operation of an engine provided with an embodiment (second embodiment) of the first and third aspects of the present invention.

FIG. 12 is a schematic diagram for explaining the operation of the engine of the second embodiment.

FIG. 13 is a schematic diagram for explaining the operation of the engine of the second embodiment.

[Explanation of symbols]

 Reference Signs List 1 engine 2d cylinder bore (cylinder) 11a to 11c intake valve opening 18 intake passage 18a first intake port (first passage) 18b second intake port (second passage) 18d, 20c, 21h partition 21b, 25 long passage, long Long pipes 21c, 26 Short passages, short pipes 23 Tumble switching valve 27 Intake passage length switching valve 40 ECU (intake control means) H Cylinder shaft

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-116226 (JP, A) JP-A-5-302562 (JP, A) JP-A-2-61326 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) F02B 27/02 F02B 31/00 331 F02B 31/02

Claims (3)

(57) [Claims] An intake passage connected to an intake valve opening of each cylinder.
Independent long and short passages for each cylinder connected to
Road and the upstream end of each of the long passage and the short passage.
Open the air inlet into the surge tank,
A throttle valve is provided at the air inlet to the cylinder, and a tumble state in which a longitudinal vortex (hereinafter referred to as a tumble) flowing in the cylinder axial direction into the cylinder is positively generated and a non-tumble state in which the non-actively generated vertical vortex is generated. Tumble generation variable means for switching, and opening and closing the short passage by a passage length switching valve.
The length of the intake passage that changes the intake passage length to the short side and the long side
Varying means and the intake control device for an engine of the tumble generating variable means the intake passage length varying means when switching the tumble state characterized by comprising an intake control means for varying the path length in the long side. 2. The system according to claim 1, wherein the tumble generation varying means biases the intake flow toward a top wall of the intake passage and a non-tumble position at which the intake passage is fully opened to generate a tumble inactively. A tumble switching valve that rotates between a tumble position at which a tumble is actively generated by flowing the fuel; and the intake control means rotates the tumble switching valve to the tumble position in a low-speed rotation range of the engine. An intake control device for an engine, wherein the control device is configured to rotate the passage length switching valve to a closed position. 3. The engine according to claim 1, wherein
And two intake valve openings. The intake passage is defined by a partition as a first passage connected to the two intake valve openings and a second passage connected to the remaining one intake valve opening. Three intake valve openings are formed so as to direct intake air flow in the cylinder axial direction, and a long passage and a short passage are connected to a junction of the first and second passages. , The tumble generation variable means,
A tumble switching valve for opening and closing the second passage;
The intake passage length changing means includes a passage length switching valve for opening and closing the short passage, and the intake control means turns the tumble switching valve and the passage length switching valve to a closed position in a low-speed rotation range of the engine. An intake control device for an engine, wherein the control device is configured to be operated.