JPH0518250A - Suction control device of engine - Google Patents

Abstract

PURPOSE:To provide the suction control device of an engine capable of improving fuel consumption during low speed torque and at a low speed period by preventing the occurrence of a problem on suction resistance during high speed operation and preventing the production of a rapid change in the sectional area of an intake air passage. CONSTITUTION:When suction control valve 21 to decrease the sectional area of a passage during low speed rotation low load operation is located in an intake air passage 17 having a suction valve opening 4c led out to a cylinder outer wall 4g, the control valve 21 has an axially extending suction recessed part 21a formed in a rod body in the shape of a circle in its cross section. The control valve 21 is arranged in parallel to and rotatably around the intake air passage 17 to a wall surface part on the mating surface 4a side with the cylinder block of the intake air passage 17. Further, when the control valve 21 is rotated to a closed position, the sectional area of the passage is decreased toward the suction valve opening 4c side and when it is rotated to a full opening position, the suction recessed part 21a forms approximately a continuous surface to the wall surface of the intake air passage 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake control device provided with an intake control valve for reducing the intake passage cross-sectional area when the engine is rotating at a low speed, and more particularly to the intake passage cross-sectional area at the intake valve opening side (downstream side). ) Relates to the improvement of the shape and arrangement of the intake control valve that can be gradually narrowed.

[0002]

2. Description of the Related Art An intake control system for an engine blows intake air into a combustion chamber in a directional manner by increasing the flow velocity even when the intake air amount is small, such as during low speed rotation or low load operation, to stabilize lean air-fuel ratio combustion. This is a device for improving the fuel consumption rate (hereinafter referred to as fuel consumption). As such an intake control device, there is a conventional one, for example, Japanese Patent Publication No. 59-576.
As disclosed in Japanese Patent Publication No. 7, an intake control plate is erected in the vicinity of the intake valve opening of the intake passage, and the control plate is erected during low speed rotation or low load operation to reduce the intake passage area. There is something I did.

[0003]

However, in the above-mentioned conventional intake control device, due to the structure in which the control plate is undulated, the control plate remains in the intake passage even when it is fully opened. There is a problem that the intake resistance increases when the intake air amount is large. Further, the above-mentioned conventional device has a structure in which only a part of the intake passage is throttled, so that the cross-sectional area of the intake passage changes abruptly, which is disadvantageous in improving low-speed torque and fuel efficiency at low speed.

The present invention has been made in view of the above-mentioned conventional problems, and it is possible to avoid the problem of intake resistance at the time of high-speed operation, etc., and to avoid a sudden change in the cross-sectional area of the intake passage to reduce low-speed torque and low-speed. It is an object of the present invention to provide an intake control device for an engine, which can improve the fuel efficiency during operation.

[0005]

SUMMARY OF THE INVENTION According to the present invention, an intake air of an engine is provided with an intake control valve for reducing a passage cross-sectional area during low speed rotation or low load operation in an intake passage leading out an intake valve opening to a cylinder outer wall. In the control device, the control valve is
An intake recess extending in the axial direction is formed in a rod body having a circular cross section, and a wall surface portion of the intake passage facing the cylinder block is rotated substantially parallel to the intake passage and around the axis. When the control valve is movably arranged and the control valve is rotated to the closed position, the passage cross-sectional area becomes narrower toward the intake valve opening side, and when the control valve is rotated to the fully open position, the intake recess is substantially continuous with the wall surface of the intake passage. It is characterized by

[0006]

According to the intake control device of the present invention, when the intake amount is small, such as during low speed rotation, the intake control valve is rotated to the closed position, whereby the cross-sectional area of the intake passage is closer to the intake valve opening side. It is gradually narrowed. Therefore, the equivalent pipe length becomes longer, the charging efficiency at the time of low speed rotation and the like is improved, and the low speed torque is improved. Further, even when the intake air amount is small, the intake air is blown into the combustion chamber in a state where the flow velocity thereof is increased, so that the lean air-fuel ratio combustion is stabilized and the fuel consumption at the time of low speed rotation is improved. Also, when the intake air amount is large, such as during high-speed rotation, the intake control valve rotates to the open position, and the intake recess is substantially flush with the wall surface of the intake passage. It is possible to prevent the intake resistance from increasing during rotation and the like.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 8 are views for explaining an intake control device for a 4-valve engine according to an embodiment of the present invention.

In the figure, 1 is a water-cooled 4-cycle parallel 4
It is a 4-valve cylinder engine, which has a crankcase 2
The cylinder block 3 and the cylinder head 4 are stacked on top of each other in a forwardly inclined state and are joined by head bolts.
The upper cover is covered with the head cover 5. Pistons 7 are slidably inserted in the four cylinder bores 3a formed in the cylinder block 3, and each piston 7 is connected to a crankshaft (not shown) by a connecting rod 8.

On the lower mating surface 4a of the cylinder head 4 on the cylinder block 3 side, a combustion concave portion 4b forming a combustion chamber is formed.
Is recessed. A spark plug 9 is screwed into the center of the combustion recess 4b, and two intake valve openings 4c and two exhaust valve openings 4d are formed around the plug 9. The valve plate 1 of the exhaust valve 10 is provided in each of the exhaust valve openings 4d.
0a, the valve plate 11a of the intake valve 11 is arranged in the intake valve opening 4c so as to open and close the respective openings 4d, 4c. The valve shafts 10b and 11b of the exhaust and intake valves 10 and 11 extend obliquely in the cylinder axis direction so as to form a predetermined angle when viewed in the cam shaft direction, and the exhaust and intake lifters 12 and 13 are provided at the upper ends thereof. Are installed respectively. Each lifter 1
The exhaust and intake camshafts 1 for driving the exhaust camshafts 1 and 2
4, 15 are arranged in a direction perpendicular to the cylinder axis and parallel to each other. Although not shown, the exhaust gas,
A cam chain that connects the intake camshafts 14 and 15 to the crankshaft is arranged in a chain chamber formed in the center of the four cylinder bores 3a.

The two exhaust valve openings 4d are led out to the front wall 4f side of the cylinder head 4 through a bifurcated exhaust passage 16, and the exhaust device 2 is provided in the wall opening 16a of the exhaust passage 16.
7 exhaust manifold 27f is connected. As shown in FIG. 5, the merging portion 27 of the exhaust manifold 27f is provided.
The exhaust control valve 2 for controlling the exhaust passage cross-sectional area is shown in a.
7c is provided, and a drive pulley 27b is fixed to one end of the exhaust control valve 27c.

The two intake valve openings 4c are led out to the rear wall 4g side of the cylinder head 4 by bifurcated intake passages 17, 17. When viewed in the cylinder axis direction, each of the intake passages 17 extends slightly inwardly with respect to a line perpendicular to the cam axis, and when viewed in the cam axis direction, the intake valve opening 4 is formed.
After being bent in an arc shape from c to the cylinder rear wall 4g side, it extends substantially linearly. A carburetor 19 is connected to the wall surface opening 17 a of the intake passage 17 via an intake manifold 18. The intake manifold 18 includes a holding bracket 1 for holding an intake control valve drive mechanism described later.
8a and a cab joint 18b are integrated, a holding bracket 18a is connected and fixed to the wall surface opening 17a, and a discharge port of the carburetor 19 is connected and fixed to the cab joint 18b. The carburetor 19 is an automatic variable venturi type having a butterfly type throttle valve 19a which opens and closes by a throttle operation, and a piston valve 19b which automatically opens and closes by an intake negative pressure of the engine. An air cleaner 20 is connected to the suction port 19c of the carburetor 19.

A valve hole 17c is formed in the bottom wall portion of each intake passage 17 so as to open to the bottom wall surface. When viewed in the cylinder axis direction, the valve hole 17c is slightly inclined inward so that the intake passages 17 are located inward toward the outside, whereas the valve hole 17c is perpendicular to the straight line connecting the cylinder axes. (See Figure 2). On the other hand, when viewed in the cam shaft direction, the intake passage 17 is slightly inclined with respect to the intake valve opening 4c closer to the inside of the intake passage.

An intake control valve 21 for changing the passage sectional area of the intake passage 17 is provided in each of the valve holes 17c so as to be rotatable around its axis. This intake control valve 21
Forms a U-groove-shaped intake recess 21a on the round bar over its entire length, and forms an inclined surface 21c at its tip.
The pinion 21b is formed at the rear end of each. The intake recess 21a forms a continuous surface with the inner wall surface of the intake passage 17 when the control valve 21 is rotated to the fully open position (see FIGS. 6 and 7). When the control valve 21 is rotated to the fully closed position, the valve hole 17 is moved as described above.
Since c is oblique to the intake passage 17,
The passage cross-sectional area of the intake passage 17 is gradually narrowed toward the downstream side (see FIGS. 1, 3, and 4).

A slide hole 18c is formed in the holding bracket 18a of the intake manifold 18 in a direction perpendicular to the control valves 21, and a plug 18d is screwed into the tip opening of the slide hole 18c. ing. The drive shaft 22 having a rack 22a is slidably inserted into the slide hole 18c, and the pinion 21b of the control valve 21 is engaged with the rack 22a. Further, one end of a drive arm 22b pivotally supported by the holding bracket 18a is connected to an outer end portion of the drive shaft 22, and a drive cable 25a is connected to the other end of the drive arm 22b.

Drive cable 25a for the intake control valve 21
The drive cable 25b connected to the drive pulley 27b of the exhaust control valve 27c is connected to the drive motor 23a, and the drive of the drive motor 23a is controlled by the control unit 23b. Note that 23c is a main switch and 23d is a battery.

Next, the function and effect of this embodiment will be described. When the intake air amount is small, such as when the engine runs at low speed or at low load, as shown in FIGS. 1, 3, and 4,
The intake control valve 21 is rotated to the fully closed position. Therefore, the intake passage 17 is narrowed from the bottom wall surface side, and only the top wall surface side is opened. In this case, since the intake control valve 21 is inclined inward of the intake passage 17 as viewed in the camshaft direction, the intake control valve 21 is gradually narrowed toward the intake valve opening 4c side. Further, when viewed in the cylinder axis direction, the intake passage 17 is oblique with respect to the line connecting the cylinder axes, whereas the intake control valve 21 is at a right angle. Is gradually narrowed down. As a result, the equivalent pipe length of the intake passage 17 is increased, the volume efficiency at low speed rotation is improved (see FIG. 8), and the low speed torque is increased accordingly. Further, the flow rate of intake air is gradually increased by the intake control valve 21 and is blown into the combustion chamber at high speed with directionality, and a vertical swirl is generated as indicated by an arrow in FIG.
As a result, combustion can be stabilized even if the air-fuel ratio is made lean, and fuel efficiency can be improved. In addition, each intake control valve 21
Since they are arranged in parallel with each other, it is possible to cope with a multi-cylinder engine without making the structure so complicated. Furthermore, when rotating at a low speed, etc., the exhaust manifold 27
The exhaust control valve 27c disposed in the collecting portion 27a of f rotates in conjunction with the intake control valve 21 to reduce the exhaust passage area. As a result, the exhaust efficiency is improved, and also from this point, the charging efficiency can be improved and the low speed torque can be improved.

When the intake air amount is large, such as when the engine is rotating at high speed or under high load operation, the intake control valve 2 is used.
1 is rotated to the fully open position, whereby the intake recess 21a forms a continuous surface with the wall surface of the intake passage 17 (see FIGS. 6 and 7), and the intake control valve 21 does not act as intake resistance.

9 and 10 show modified examples of the intake concave portion of the intake control valve, in which the same reference numerals as those in FIGS. 3 and 4 indicate the same or corresponding portions. In this modification, an inclined surface 21d is formed on the back side of the intake recess 21a of the intake control valve 21. When viewed in the intake passage direction, the inclined surface 21d is formed so that the boundary portion between the adjacent intake passages 17, 17, that is, the cylinder central portion, becomes lower. As a result, when the intake control valve 21 is rotated to the fully closed position, the portion of the intake passage corresponding to the center of the cylinder opens larger,
Therefore, a large amount of intake air flows into the center of the combustion chamber.

11 and 12 show an embodiment in which the present invention is applied to a fuel injection engine. In the drawings, the same symbols as those in FIG. 1 indicate the same or corresponding parts. In the present embodiment, the fuel injection valve 26 is mounted on the top wall portion of the intake passage 17, and the injection nozzle of the fuel injection valve 26 is installed through the injection hole 26a.
It is directed to the tip portion of No. 1, that is, the portion extending from the most narrowed intake passage area to the back surface of the valve plate 11a of the intake valve 11. A throttle body 24 is connected to the rear wall opening 17a of the intake passage 17 via an intake manifold 18, and a throttle valve 24a is rotatably arranged in the body 24. Although not shown, the throttle valve 24a is drive-controlled in conjunction with the drive shaft 22. In the present embodiment, the fuel injected from the fuel injection valve 26 also hits the intake control valve 21, so that the control valve 21 can be cooled. Further, since the fuel is injected into the most narrowed portion of the intake passage area, the fuel transfer delay is small,
And the atomization becomes good.

By the way, in the present invention, since the intake control valve for controlling the intake passage area is provided, the lean air-fuel ratio combustion can be stabilized, CO can be reduced and fuel consumption can be improved, but the exhaust temperature is lowered. However, there is a concern that the treatment of HC by the catalyst will be difficult to perform. Particularly in the case of a high-speed engine, it is considered that the catalyst is arranged as far as possible from the engine in order to reduce the resistance of the exhaust gas, so that the exhaust gas temperature is further lowered and the above problem becomes more remarkable. On the other hand, when the catalyst is brought close to the engine by simply shortening the exhaust pipe, there is a concern that the exhaust efficiency will deteriorate at low speed rotation and the engine performance will decrease.

FIGS. 13 and 14 show a catalyst arrangement structure in which the catalyst can be arranged as close to the engine as possible in order to solve the problem caused by the decrease in exhaust temperature. In the drawing, 27 is an exhaust device, which is an exhaust manifold connected to the exhaust port of each cylinder (see reference numeral 27f in FIG. 1).
Each exhaust pipe 27g connected to the
7a, and the catalyst chamber 27e
Is integrally formed with the silencer 2 in the chamber 27e.
It has a structure in which 7d is connected. Inside the collecting portion 27a, an exhaust control valve 27c for controlling the area of the opening 27h inside the collecting portion of each of the exhaust pipes 27g, that is, the area of the exhaust passage is disposed, and the catalyst chamber 27e following the collecting portion 27a. A catalyst unit 28 is arranged inside. The exhaust control valve 27c is controlled in conjunction with the intake control valve via a wire cable (not shown) wound around the pulley 27b.

In this arrangement structure, the exhaust control valve 27c for narrowing the exhaust passage area is provided when the engine rotates at low speed, so that the operation at low speed can be stabilized even if the exhaust pipe length is shortened.
As described above, when the exhaust pipe length is shortened, the negative pressure wave of the exhaust acts on the exhaust valve opening at the time of high speed rotation to improve the exhaust efficiency, but the positive pressure wave of the exhaust acts on the exhaust valve opening at the time of low speed rotation. Efficiency is reduced. However, in this embodiment, the positive pressure wave of the exhaust can be canceled by the exhaust control valve 27c, and the above-described stabilization can be achieved. Therefore, as compared with the case where the exhaust control valve is not provided, the catalyst 28 can be brought closer to the exhaust port of the engine, and the decrease in exhaust temperature can be suppressed accordingly, which is advantageous in the treatment of HC. In addition, the heat capacity of the exhaust pipe is reduced by the amount of shortening the exhaust pipe length, which shortens the time until the activation of the engine at the start.

As described above, the present arrangement structure in which the exhaust control valve 27c is provided and the catalyst 28 is disposed immediately downstream of the exhaust control valve 27c is stabilized by controlling the intake passage area as in the above embodiment. It is effective for the engine that can.

FIGS. 15 to 18 show that the exhaust pipe length can be lengthened at low and medium speeds of the engine and shortened at high speeds.
Further, it is another catalyst arrangement structure capable of suppressing a decrease in exhaust temperature, and in the drawings, the same reference numerals as those in FIGS. 13 and 14 indicate the same or corresponding portions. In this arrangement structure, each exhaust pipe is divided into a front exhaust pipe 27g and a rear exhaust pipe 27i, and a valve chamber 27j and a catalyst chamber 27e are provided therebetween. A catalyst 28 is arranged in the catalyst chamber 27e. The catalyst 28 is of a monolith type in which a large number of lattice-shaped passages 28a pass through from the upstream side to the downstream side. The rear exhaust pipes 27i are gathered on the left side in the drawing, and the valve chamber 27j has a shape that bulges upward.

A sluice valve 30 is provided in the valve chamber 27j.
However, each of the front exhaust pipes 2 and the standby position located in the bulging portion
It is arranged so as to be rotatable in the vertical direction between a partition position located on the extension of 7 g. This sluice valve 30 has a valve shaft 30.
The five valve plates 30b are fixed to a and each of the valve plates 3
The upper surface of 0b is covered with a cover plate 30d. Further, the sluice valve 30 is controlled to be opened / closed by a control motor (not shown) via a drive pulley 30c mounted on the outward protruding end of the valve shaft 30a and a drive cable 30e wound around the drive pulley 30c.

When rotating at a low speed, the sluice valve 30 rotates to a sluice position, whereby the front exhaust pipe 27g has a passage formed by the sluice plate 30b, the cover plate 30d and the bottom surface of the valve chamber 27j, and the catalyst. It communicates with the rear exhaust pipe 27i via a passage constituted by 28. Further, at the time of high speed rotation, the sluice valve 30 rotates to the standby position, whereby the front exhaust pipes 27g are gathered by the valve chamber 27j, so that the exhaust pipe length becomes shorter than that at the low speed rotation.

As described above, in the present arrangement structure, the exhaust pipes are separated into the front and the rear, and the catalyst 28 is arranged between them, so that the catalyst 28 is close to the exhaust port, and the temperature decrease of the exhaust gas can be suppressed accordingly. Also, at low speed rotation, the sluice valve 30,
By connecting the front and rear exhaust pipes with the catalyst 28, the exhaust pipe length can be increased, and the exhaust pipe length can be shortened by collecting the front exhaust pipe 27g in the valve chamber 27j during high speed rotation. As a result, it is possible to improve the output during both low speed rotation and high speed rotation.

As described above, according to the intake control device for an engine of the present invention, the intake control valve is a rod-shaped member and is arranged in the bottom wall portion of the intake passage in the direction of the passage. Can gradually reduce the cross-sectional area of the intake passage toward the downstream side, which increases the equivalent pipe length during low-speed rotation, etc., and has the effect of improving charging efficiency and improving low-speed torque. The intake air can be blown into the combustion chamber at a high flow rate, lean air-fuel ratio combustion can be stabilized, and low-speed fuel consumption can be improved. Furthermore, at the time of high speed rotation and the like, since the intake recess of the intake control valve forms a substantially continuous surface with the wall surface of the intake passage, intake resistance does not increase.

[Brief description of drawings]

FIG. 1 is a sectional side view of an intake control device for an engine according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

5 is a sectional view taken along line VV of FIG.

FIG. 6 is a cross-sectional view showing a state of the intake control valve of the above embodiment during high speed rotation and the like.

FIG. 7 is a cross-sectional view showing a state of the intake control valve of the above embodiment during high speed rotation and the like.

FIG. 8 is an engine speed-volume efficiency characteristic diagram for explaining the function and effect of the above embodiment.

FIG. 9 is a cross-sectional view showing a modification of the intake control valve portion of the above embodiment.

FIG. 10 is a cross-sectional view showing a modification of the intake control valve portion of the above embodiment.

FIG. 11 is a cross-sectional side view showing an embodiment when the present invention is applied to a combustion injection type engine.

12 is a sectional view taken along line XII-XII in FIG.

FIG. 13 is a cross-sectional plan view showing a catalyst arrangement structure suitable for an engine equipped with the intake control device of the above embodiment.

FIG. 14 is a sectional side view of the catalyst arrangement structure.

FIG. 15 is a cross-sectional side view showing another catalyst arrangement structure suitable for an engine equipped with the intake control device of the above embodiment.

FIG. 16 is a cross-sectional plan view of the another catalyst arrangement structure.

17 is a sectional view taken along line XVII-XVII in FIG.

18 is a sectional view taken along line XVIII-XVIII in FIG.

[Explanation of symbols]

 1 Engine 4a Interfacing 4c Intake valve opening 4g Cylinder outer wall 17 Intake passage 21 Intake control valve 21a Intake recess

Claims (1)

Claim: What is claimed is: 1. An intake control device for an engine, comprising an intake control valve for reducing a passage cross-sectional area during low-speed rotation or low-load operation, in an intake passage leading out an intake valve opening to an outer wall of a cylinder. In the above, the control valve is formed by forming an intake recess extending axially in a rod body having a circular cross section, and
The intake passage is disposed on a wall surface portion of the intake passage facing the cylinder block so as to be rotatable about the axis and substantially parallel to the intake passage. When the control valve is rotated to the closed position, the passage cross-sectional area is the intake air. An intake control device for an engine, characterized in that the intake recess is narrowed toward the valve opening side and the intake recess forms a substantially continuous surface with the wall surface of the intake passage when rotated to the fully open position.