JP3279600B2 - 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, in which the flow rate can be increased even when the amount of intake air is small by narrowing an intake passage area at low or medium speed rotation. More specifically, the present invention relates to a structure capable of simultaneously generating both a so-called vertical swirl and a horizontal swirl.

[0002]

2. Description of the Related Art In order to improve the fuel efficiency of an engine, it is effective to increase the flow velocity even at a low intake air amount to generate, for example, a vertical swirl in a combustion chamber to stabilize the combustion of a lean mixture. Conventionally, as an intake control device capable of generating such a vertical swirl, as disclosed in Japanese Patent Publication No. 59-5767, for example, a control plate is arranged so as to be able to undulate near an intake valve opening of an intake passage so as to be low. In some cases, the control plate is raised when the engine rotates at a medium speed to reduce the area of the intake passage.

[0003]

Incidentally, in order to further improve the fuel efficiency in the low-medium-speed rotation or low-medium load operation range of the engine, it is desirable that horizontal swirl can be generated simultaneously in addition to the above-described vertical swirl. In the conventional device, the simultaneous occurrence of such vertical and horizontal swirl is not considered.

[0004] The present invention has been made in view of the above-mentioned conventional situation, and it is possible to simultaneously generate vertical swirl and horizontal swirl, thereby further improving the atomization of fuel and the uniformity of air-fuel mixture distribution. It is an object of the present invention to provide an intake control device for an engine that can stabilize combustion with a lean air-fuel mixture and consequently improve fuel efficiency.

[0005]

SUMMARY OF THE INVENTION The present invention provides two cylinders per cylinder.
An intake passage composed of two branch passages for leading two intake valve openings to the outer wall of the cylinder head is provided, and two round bars are provided on the bottom wall portion facing the cylinder block downstream of the branch point of the intake passage. The intake recess is recessed, and in the fully open position, it is immersed in the bottom wall to fully open the two branch passages. An intake control valve to be opened is arranged, and both of the branch passages are opened at a fully open position on the upstream side of the intake control valve,
In the fully closed position, an auxiliary throttle valve that opens one of the branch passages and closes the other is provided.In the low-speed rotation range or the low-load operation range, the auxiliary throttle valve and the intake control valve are rotated to the fully closed position. In the middle-speed rotation range or the middle-load operation range, the auxiliary throttle valve is opened first, and then the intake control valve is opened.In the high-speed rotation or the high-load operation range, the auxiliary throttle valve and the intake control valve are fully opened. An intake control device for an engine, comprising a valve opening / closing control means for rotating the valve to a position.

[0006]

According to the intake control device of the present invention, when the intake air amount is small, such as in the low-speed rotation or low-load operation range, the auxiliary throttle valve closes the other branch passage and opens only one branch passage. In addition, the intake control valve rotates to the closed position to narrow the branch passage from the bottom wall side. As a result, the intake air flows to the branch passage on the side where the auxiliary throttle valve is open, and flows to the ceiling wall side of the branch passage on the side. As a result, the intake air is combusted while generating a horizontal swirl going from the intake valve opening on the side where the auxiliary throttle valve is open to the opposite side and generating a vertical swirl going downward from the ceiling wall side. It will be blown into the room. Thereby, a vertical swirl and a horizontal swirl are generated at the same time, and the atomization of the fuel and the uniformity of the mixture distribution are promoted. Further, in the middle-speed rotation or middle-load operation range, the auxiliary throttle valve starts to open first, and the intake control valve starts to open later. Changes smoothly to a combustion state in which no combustion occurs.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to 4 are views for explaining an intake control device for a four-valve engine according to one embodiment of the present invention. FIG. 1 is a plan view, and FIGS. 2 and 3 are II-II and III- of FIG.
FIG. 4 is an engine speed-valve opening degree characteristic diagram showing the operation of each valve.

In the figure, 1 is a water-cooled 4-cycle parallel 4
It is a four-cylinder cylinder engine, which has two crankcases.
The cylinder block 3 and the cylinder head 4 are stacked on the upper side in a forwardly inclined state and connected with a head bolt.
And a structure in which a head cover 5 is put on the upper mating surface of the head. A piston 7 is slidably inserted into each of 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.

A lower surface 4a of the cylinder head 4 on the side of the cylinder block 3 has a combustion recess 4b forming a combustion chamber.
Is recessed. An ignition 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 opened around the plug 9. The valve plate 1 of the exhaust valve 10 is provided in each exhaust valve opening 4d.
In the intake valve opening 4c, a valve plate 11a of the intake valve 11 is disposed so as to open and close the openings 4d and 4c, respectively. The valve shafts of the exhaust and intake valves 10 and 11 extend obliquely upward in the cylinder axial direction so as to form a predetermined included angle when viewed in the cam axis direction, and exhaust and intake lifters 12 and 13 are respectively mounted on upper ends thereof. Have been. On each of the lifters 12, 13,
Exhaust and intake camshafts 14 and 15 for driving this are arranged in a direction perpendicular to the cylinder axis and parallel to each other.

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 an exhaust pipe (not shown) is formed in the wall opening 16a of the exhaust passage 16. Is connected. Further, the two intake valve openings 4c are provided with a bifurcated intake passage 17 composed of a turning inside passage (branch passage) 17g and a turning outside passage (branch passage) 17h.
At the rear wall 4g side of the cylinder head 4. The intake passage 17 extends in a direction substantially perpendicular to the camshaft 15 when viewed in the cylinder axis direction, and after being bent in an arc shape from the intake valve opening 4c to the cylinder rear wall 4g side when viewed in the camshaft direction. , And extend substantially linearly. And the above intake passage 1
An auxiliary valve body 27 is connected to the wall opening 17a of the throttle 7, a throttle body 24 is connected to the body 27 via a joint 18, and an air cleaner 20 is further connected to the body 27.

A valve hole 17c is formed in the vicinity of the arc-shaped bent portion 17b of the intake passage 17 in the cam axis direction. The valve hole 17c is formed so that its axis is located near the bottom wall 17d surface of the intake passage 17 and near the bent portion 17b between the axis of the intake valve 11 and the intake side head bolt. And penetrates two adjacent intake passages 17. An intake control valve 21 for changing the passage sectional area of the intake passage 17 is rotatably disposed in the valve hole 17c. The control valves 21 are arranged in a pair on the left and right sides of a cam chain arranged at the center of the engine.
Is cut out, and the drive arm 21 is
b is fixed. The intake recess 21a is
When fully opened, it forms a part of the bottom wall 17 d surface and the side wall surface of the intake passage 17. Also, this intake recess 21a is
When fully closed, the portion of the intake passage 17 on the bottom wall 17d side is narrowed, and only the top wall side portion is opened.

A fuel injection valve 26 is arranged on the top wall side of the turning inner passage 17g of each of the cylinder intake passages 17, and an injection nozzle of the injection valve 26 is connected to the turning inner passage 17g through an injection hole 26a. Of the intake valve opening 4c.

An auxiliary throttle valve 28 is provided in the auxiliary valve body 27. The auxiliary throttle valve 28 has a structure in which a pair of auxiliary valve plates 29 are fixed by bolting to an auxiliary valve shaft 28a penetrating through the auxiliary valve body 27 in the cam shaft direction. A drive arm 28b is fixed to the protruding end. A notch 2 is formed in a portion of the auxiliary valve plate 29 facing the turning outer passage 17h on the side where the fuel injection valve 26 is not disposed.
9a, whereby the auxiliary throttle valve 28 is formed.
Is rotated to the closed position, only the turning inner passage 17g on the side where the fuel injection valve 26 is disposed is closed.

A throttle valve 30 is provided in the throttle body 24. This throttle valve 30
The throttle valve shaft 30c has a structure in which a pair of throttle valve plates 30a are bolted and fixed to a throttle valve shaft 30c penetratingly disposed in the direction of the camshaft in the throttle body 24. 30b is fixed. The drive arm 30b is connected to the throttle grip 25 via a drive cable 25a.

The auxiliary throttle valve 28 and the intake control valve 2
1 is connected to a valve opening / closing control device 31. The control device 31 includes a drive arm 28 b for each of the valves 28 and 21,
Drive motors 31b and 31c connected to the drive motor 21b, and control signals a and b for supplying the drive motors 31b and 31c to the drive motors 31b and 31c, respectively.
And a PU 31a. The CPU 31 sets the control signals a and b according to the opening of the throttle valve 30 or the engine speed so that the valves 28 and 21 have the opening shown in FIG.

Next, the operation and effect of this embodiment will be described. In the present embodiment, the CPU 31a outputs control signals a and b corresponding to the engine speed and the throttle opening to the drive motors 31b and 31c, whereby the auxiliary throttle valve 2 is driven.
8. The intake control valve 21 is controlled to the opening indicated by the curves B and C in FIG. First, when the engine speed is in a low speed range or in a low load operation range where the throttle opening is small, the auxiliary throttle valve 28 and the intake control valve 21 are rotated to the fully closed position. Thereby, the auxiliary throttle valve 28 closes the passage 17g inside the turning where the fuel injection valve 26 is disposed. Further, the intake control valve 21 narrows each passage from the bottom wall 17d side, and opens only the top wall side. As a result, as shown in FIG. 1, the intake air is blown into the combustion chamber only at the open swirl outside passage 17h and at a high speed biased to the ceiling wall side, and the lateral swirl flows from the swirl outside passage side to the opposite side. As well as a vertical swirl going downward from the top wall side.

When the engine speed is in the middle speed range or when the throttle opening is in the middle load range, the auxiliary throttle valve 28 starts to open first, and then the intake control valve 21 opens. Start (see FIG. 4). As a result, the intake air gradually flows into the turning inner passage 17g, and the flow along the ceiling wall is weakened. Therefore, the horizontal swirl is weakened first, and then the vertical swirl is weakened. In the high-speed rotation range and the high load range, the auxiliary throttle valve 28 and the intake control valve 2
1 are fully opened, and the flow of intake air is the same as that of the conventional intake device.

As described above, in the present embodiment, in the low-speed rotation range and the low-load operation range, the auxiliary throttle valve 28 controls the turning inside passage 1.
7g is closed and only the turning outer passage 17h is opened.
Since only the top wall is opened by narrowing the bottom wall 17d side by the intake control valve 21, both the horizontal swirl and the vertical swirl can be generated simultaneously with a low intake air amount, and the fuel is atomized. , The distribution of the air-fuel mixture can be made uniform, the combustion of the lean air-fuel mixture can be stabilized, and the fuel efficiency can be improved.

In the above embodiment, the auxiliary throttle valve 28 is arranged at the junction (upstream side) of the intake passage. However, the arrangement position of this throttle valve is not limited to the above embodiment.
For example, as shown in FIG. 5, a branch portion (downstream side) of the intake passage
May be arranged. In this embodiment, the turning inside passage 17 is used.
The single auxiliary throttle valve plate 29 is located within g. Further, in the above embodiment, the case of the fuel injection type engine has been described. However, the present invention can of course be applied to a carburetor type engine.

[0020]

As described above, according to the intake control system for an engine according to the present invention, in a low-speed rotation region or the like, only one of the two branch passages is opened, and the bottom wall side of the branch passage is narrowed. Since only the top wall is opened, both the horizontal swirl and the vertical swirl can be generated at the same time even in the case of a low intake air amount, and there is an effect that the lean air-fuel mixture combustion is stabilized and the fuel efficiency is improved. Further, in the middle speed range, the auxiliary throttle valve starts to open first, and the intake control valve starts to open later than this, so that there is an effect that the change in the combustion state of the engine can be made smooth.

[Brief description of the drawings]

FIG. 1 is a sectional plan view showing 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.

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

FIG. 4 is a valve opening characteristic diagram for explaining the operation of the embodiment device.

FIG. 5 is a sectional plan view showing a modification of the arrangement position of the auxiliary throttle valve in the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 3a Bore (cylinder) 4a Downstream joint (joint with cylinder block) 4c Intake valve opening 4g Cylinder head outer wall 17 Intake passage 17d Bottom wall 21 Intake control valve 28 Auxiliary throttle valve 31 Valve opening and closing control device

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ identification code FI F02M 69/00 360 F02M 69/00 360C (58) Field surveyed (Int. Cl. ⁷ , DB name) F02B 31/02 F02D 9 / 02 361 F02D 13/02 F02M 69/00 360

Claims (1)

(57) [Claims] 1. A two intake valve openings per cylinder provided an intake passage of two branch passages to derive the cylinder head outer wall, the bottom wall of the mating face side and the downstream side of the cylinder block from the branching point of the intake passage In the part, two intake recesses on the round bar
It is recessed, immersed in the bottom wall at the fully open position and
Fully open both branch passages, and in the fully closed position,
An intake control valve that closes the bottom wall side portion and opens only the top wall side portion is provided.
Open both branch passages, and in the fully closed position,
An auxiliary throttle valve that opens one and closes the other is provided ,
In the low-speed rotation range or the low-load operation range, the auxiliary throttle valve and suction
Rotate the air control valve to the fully closed position,
In the operating range, first open the auxiliary throttle valve, and then
Open the intake control valve to operate at high speed or high load
Then, rotate the auxiliary throttle valve and intake control valve to the fully open position.
An intake control device for an engine, further comprising a valve opening / closing control unit for causing the engine to open and close.