JPH081131B2 - Internal combustion engine intake system - Google Patents

Description

Description: [Industrial application] The present invention has an object of providing an intake system for an internal combustion engine that controls a flow of intake air by providing a control valve to improve combustion.

[Prior Art] Generally, in an internal combustion engine, a strong swirl is generated in the combustion chamber in the low load region of the engine to cause intake turbulence to improve combustion efficiency, while the swirl is suppressed in the high load region to reduce intake charge efficiency. It is necessary to increase the output and to improve the output.

For this reason, conventionally, a swirl control valve having a cutout portion is provided in the intake passage downstream of the throttle valve, and the control valve is fully closed in the low load region to introduce intake air from the cutout portion to generate a powerful swirl. It has been proposed that the control valve be fully opened in the load region to improve the charging efficiency.

For example, in Japanese Patent Laid-Open No. 61-112732, when the control valve having the cutout portion is fully closed, the cutout portion is positioned on the lower wall side of the intake port when the engine is cold, and the combustion plug adheres to the ignition plug. While preventing so-called fogging, the control valve is reversed from this state during warm-up to be fully closed, and the notch is positioned on the upper wall side of the intake port to generate a stronger swirl.

In both the cold and warm states described above, the control valve is not perpendicular to the intake air, but is inclined to the intake valve side when cold, and the notch is located on the lower wall side of the intake port. On the other hand, during warm-up, the notch is located on the upper wall side of the intake port while being tilted backward with respect to the intake valve.

[Problems to be Solved by the Invention] In the conventional intake device described above, the inclination of the control valve with respect to the intake port when fully closed is not particularly considered from the viewpoint of swirl, and the control valve circumference of the cutout portion is not taken into consideration. Since the directional position is not particularly considered, it is difficult to obtain a proper intake flow and stable combustion is not obtained.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an intake device in which a proper intake flow is obtained and combustion is stabilized.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a control valve having a cutout portion for opening and closing an intake passage by rotation of a control valve shaft,
The control valve is provided in the intake passage downstream of the throttle valve, and when the control valve is fully closed, the control valve is inclined forward to the intake valve side with respect to a plane perpendicular to the center line of the intake passage, and the intake port at the combustion chamber side opening of the intake port is provided. Of the two divided parts on the opposite side to the side, the arc of the substantially four divided parts on the outer peripheral side of the cylinder is set as the first circular arc,
Among the two intersections of the outer periphery of the control valve and the control valve shaft, the intersections along the outer periphery of the control valve on the upper wall surface side of the intake passage from the intersections that are at least distant from the cylinder center line perpendicular to the cylinder row direction. A second arc having a length substantially equal to the length of the first arc is set, and the notch is provided at the center of gravity on the area of the control valve corresponding to the second arc.

Further, according to the present invention, a sub-control valve is provided downstream of the control valve, the cut-out having an area smaller than the cut-out of the control valve, and the sub-control valve being perpendicular to the center line of the intake passage when fully closed.

[Operation] When the control valve is fully closed, the control valve leans forward to the intake valve side with respect to the intake passage, so the intake air is guided by the control valve and flows out through the notch at the tip of the forward leaning side, and then along the intake passage. It smoothly flows into the combustion chamber. As a result, an optimum intake flow can be obtained and stable combustion can be obtained.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 to 11 relate to the first embodiment, FIG. 1 is a plan sectional view of an intake device, and FIG. 3 is a longitudinal sectional view thereof. An intake port 3 and an exhaust port 5 are formed in the cylinder head 1, and an intake valve 7 and an exhaust valve 9 are provided in the ports 3 and 5, respectively. The intake port 3 is gradually curved from the opening 13 at the upper portion of the combustion chamber 11 toward the upstream side, and forms a portion 19 near the intake manifold 15 that is substantially orthogonal to the cylinder center axis 17. A swirl control valve 23 having a cutout portion 21 is provided in this portion 19 so as to be able to open and close the intake port 3 while being supported by a control valve shaft 25. Intake passage with intake manifold 15 and intake port 3 of cylinder head 1
Forming fourteen. Reference numeral 22 is a spark plug.

The swirl control valve 23 is inclined forward by α ° toward the intake valve 7 side with respect to a plane 30 perpendicular to the center line 28 of the intake passage 14 when fully closed. In addition, the length of the first circular arc of a substantially four-divided portion 29 on the cylinder outer peripheral side of the semicircular two-divided portions on the side opposite to the intake port 3 side in the opening 13 on the combustion chamber 11 side of the intake port 3 is set. l ₁ , while the outer circumference of the swirl control valve 23 and the control valve shaft
Of the intersections A and B with the central axis 26 of 25, the swirl control valve on the upper wall surface 16 side of the intake passage 14 from the intersection A farther from the cylinder center line 18 perpendicular to the cylinder row direction (vertical direction in FIG. 1).
23 A swirl control shown in FIG. 2 corresponding to a second circular arc formed by the intersection points A and C, with a point C that is substantially equal to the length l ₁ of the first circular arc along the outer circumference. The center of gravity of the notch 21 is provided on the area portion 31 of the valve 23.

That is, the length l ₁ of the first circular arc of the four-divided portion 29, the length l ₂ of the circular arc of the area portion 31, and the length of the second circular arc formed by the points A and C of the swirl control valve 23. l ₃ are almost equal to each other.

Reference numeral 27 indicates a line connecting a portion of the 4-divided portion 29 on the side farthest from the intake port 3 side and a point C on the area portion 31.

4 to 7 show specific examples of the notch 21. The center of gravity of each notch 21 is indicated by G. The center of gravity G is located on the area portion 31.

With this configuration, when the intake valve 7 when the swirl control valve 23 is fully closed is opened, the intake air flowing through the intake manifold 15 passes through the cutout portion 21 of the swirl control valve 23 and enters the combustion chamber.
It flows to the 11 side. At this time, the swirl control valve 23 changes the intake valve 7
Since it is inclined forward by α ° to the side, the intake air on the lower wall side of the intake port 3 flows along the inclination of the swirl control valve 23 toward the upper wall surface 16 where the cutout portion 21 is provided and flows to the cutout portion 21. Since it reaches the combustion chamber 11 side smoothly from the cutout portion 21 along with the intake air flowing on the upper wall surface 16 side of the intake port 3, the center of gravity of the cutout portion 21 does not collide with the inner wall of the intake port 3 as described above. Since it is located at this position, the main flow of intake air that has passed through the notch 21 flows along the intake port 3 and then flows into the deepest part of the combustion chamber 11 from the four-divided portion 29 of the opening 13 of the intake port 3. Therefore, a swirl with a uniform change of swirl ratio is generated in the combustion chamber 11, and it becomes possible to keep the damping of the swirl to the minimum until the latter half of the compression stroke, and the flame propagation is stable in the combustion stroke without being obstructed. The fuel consumption, emission, and drivability are greatly improved.

Then, at the time of full load, the swirl control valve 23 is fully opened, and the intake charging efficiency is improved.

Fig. 8 shows engine speed N = 1400 rpm, indicated mean effective pressure
Pi = 0.31MPa, air-fuel ratio A / E = 22.5, ignition advance angle is MBT, and the tilt angle of swirl control valve 32 in Fig. 9, which corresponds to the view from the IX arrow direction in Fig. 3, Some α is 0 °, 5 °, 15 °, 30
For each state of °, the fluctuation rate of the indicated mean effective pressure depending on the position of the notch 34 (represented by θ °) is shown. The position of the notch 34 is positive (+) on the upper side of the horizontal center line 33, negative (-) on the lower side, and is on the right side (side) of the vertical center line 35. Each of the inclination angles is shown by a solid line, and the left side (side) is also shown by a broken line.

In the experiment, as shown in Fig. 9, the swirl control valve
32 is an elliptical shape, and the angle of the notch position θ is 16 mm from the peripheral portion of the control valve 32 that intersects with the major axis of the ellipse (the center line 33 on the horizontal side).
The position is taken as the center. Also, the notch 34 has a diameter
It has an arc shape cut out by a 26 mm circle. Furthermore, the diameter of the combustion chamber side opening of the intake manifold is 32 mm.

As is clear from FIG. 8 described above, it is α = 15 ° that the fluctuation rate of the indicated mean effective pressure is low and the combustion is stable, and the position of the notch 34 is irrespective of the inclination angle α. The condition is that θ = 0 ° to 90 °. Therefore, as shown in FIG. 1 and FIG. 2 showing the first embodiment, the position of the center of gravity of the notch 21 is set to the combustion chamber 11 of the intake port 3.
Of the semicircular two-sided portion of the side opening 13 on the side opposite to the intake port 3 side, a substantially four-sided portion on the cylinder outer peripheral side 29
The length of the first circular arc of L1 is set to l ₁ , while the swirl control valve 23
Of the intersections A and B between the outer periphery of the cylinder and the central axis 26 of the control valve shaft 25, which is farther from the cylinder center line 18 which is perpendicular to the cylinder row direction (vertical direction in FIG. 1), the upper wall surface of the intake passage 14 Along the outer circumference of the swirl control valve 23 on the 16th side, a point substantially equal to the length l _{1 of the first} circular arc is defined as a point C, and FIG. 2 corresponding to the circular arc formed by the intersection A and the point C is shown in FIG. By providing it on the area part 31 of the swirl control valve 23 shown, the notch 21
Is located in the range of θ = 0 ° to 90 ° on the upper side of the horizontal center line 33 and on the right side of the vertical center line 35 in FIG. 9 by the experiment, and stable combustion can be obtained. Become.

FIG. 10 shows the air-fuel ratio A / F under the conditions of engine speed N = 1400 rpm, indicated mean effective pressure Pi = 0.31 MPa, and ignition advance angle MBT.
When the inclination angle α of the swirl control valve 32 in FIG. 9 is α = 15 ° and the position of the notch 34 is θ = 60 ° (shown by the solid line), α = When α = 60 ° at 0 ° (dashed line), θ = − at α = 15 °
It is shown for three cases, at 20 ° (shown by a broken line). According to FIG. 10 as well, similar to the result of FIG. 8 described above, the swirl control valve 32 is tilted forward by 15 ° and the position of the notch 34 is θ = 60 °, that is, FIG. 1 and FIG. The position shown in FIG. 2 is good, at which time both stability and fuel economy are greatly improved.

In addition, the data of FIG. 8 and FIG. 10 described above are obtained by conducting an experiment with the gap between the swirl control valve 32 and the intake port wall being constant, and the swirl control valve at the time of low load being in the upright state and being connected to the intake port. In a system in which the gap is fixed and the opening of the swirl control valve increases as the load increases, the gap with the intake port becomes large, and it is not possible to obtain a directional and uniform swirl, and stable combustion is obtained. I knew I couldn't.

FIG. 11 shows the engine speed N = 1400 rpm and the charging efficiency ηc = 40.
% Of the gas flow characteristics in the combustion chamber with a laser Doppler velocity meter at α = 15 ° and θ = 60 °, at α = 0 ° and θ = 60 °, and at α = 15 °. 3 with θ = -20 °
It shows the street. In the figure, the solid line shows 60 ° (BTDC) before the top dead center when the intake opening begins, the dashed line shows 30 ° (BTDC), and the broken line shows 0 ° (BTDC). According to FIG. 11 also, as in FIG. 10, the condition of α = 15 ° and θ = 60 ° is good, there is no intersection of streamlines in the compression stroke, which is seen in other conditions, and the initial combustion engine from the ignition timing. A uniform swirl ratio is obtained over time.

12 and 13 show a second embodiment. This embodiment is a modification of the first embodiment, and is an example in which there are two intake valves 7. In this embodiment, the intake port shape is a Siamese type and the openings 13a, 13b of the intake ports 3a, 3b to the combustion chamber 11 are formed. It is a thing. Also in this case, the swirl control valve 23 is tilted forward as in the first embodiment, and the center of gravity of the notch 21 is also the opening 13a of the intake port 3 on the side of the combustion chamber 11 as in the first embodiment. In the semicircular divided portion on the side opposite to the intake port 3 side, the length of the first circular arc of the substantially divided 4 portion 29a on the cylinder outer peripheral side is set to l ₁ , while the outer circumference of the swirl control valve 23 Of the intersections A and B with the center axis 26 of the control valve shaft 25, from the intersection A farther from the cylinder center line 18 which is perpendicular to the cylinder row direction (vertical direction in FIG. 1), the upper surface 16 side of the intake passage 14 is located. Along the outer circumference of the swirl control valve 23, the point that becomes substantially equal to the length l ₁ of the first arc is a point C, and the swirl control valve corresponding to the second arc formed by the intersection A and the point C. Since the swirl control valve 23 is fully closed, the intake air passes through the notch portion 21 because it is provided on the area portion 31 of 23, which is the same as in the first embodiment. Such a uniform swirl can be obtained, and the combustion can be greatly improved.

Then, at the time of full load, the swirl control valve 23 is fully opened, and the intake air flows into the combustion chamber 11 through the two intake ports 3a and 3b, so that the intake charging efficiency is further improved.

In the second embodiment, the cutout 21 may be provided on the lower intake port 3b side in the drawing. This is indicated by a broken line.
The position of the center of gravity of the cutout portion 21 is the four-divided portion 29a of the opening 13a.
Needless to say, it is located at the above-mentioned corresponding portion in the four-divided portion 29b of the opening 13b corresponding to the symmetrical position in the vertical direction in the figure. Further, a dual port type may be used instead of the Siamese type, and in this case, either one of the intake ports may be provided with a swirl control valve having a notch at a predetermined position. Furthermore, the second embodiment may be applied to an engine having two exhaust valves. Also, in each of the first and second embodiments,
The swirl control valve 23 may be provided in the intake manifold 15.

14 and 15 show a third embodiment. In this embodiment, a swirl control valve 23 having a cutout 21 similar to that of the first and second embodiments is provided in the intake manifold 15, and the valve shaft is provided in the intake port 3 in the cylinder head 1 downstream thereof. A sub control valve 41 having a notch 39 fixed to 37 is rotatably provided. The swirl control valve 23 is inclined forward by α ° as in the first embodiment, and the position of the center of gravity of the notch 21 is also provided at the same position as in the first embodiment. On the other hand, the sub control valve 41 is not inclined when it is fully closed, and is substantially perpendicular to the center line 28 of the intake passage 14. Sub control valve 41 notch
39 is on the passage that connects the notch 21 of the swirl control valve 23 and the four-divided portion 29 of the opening 13 of the intake port 3, and its area is smaller than the area of the notch 21 surface of the swirl control valve 23. is there.

In this case, both the swirl control valve 23 and the sub control valve 41 are fully closed in the extremely low load range including idling, and at this time, the sub control valve 41 is perpendicular to the intake port 3. On the other hand, as shown in FIG. 16, the engine speed N = 700 rpm, the indicated mean effective pressure Pi = 0.08 MPa, and the air-fuel ratio A / F = 15, which are extremely low load conditions including idling (the experimental device is shown in FIG. 11 to 13), the fluctuation rate of the indicated mean effective pressure in the notch position increases as the tilt angle α of the swirl control valve in FIG. 9 increases. Here, the data is shown when the notch is on the right side (side) of the center line 35 on the vertical side in FIG. 9, but the opposite side (side) shows the same tendency. As a result of gas flow measurement, when the control valve is upright (α = 0 °), the flow line in the intake port is disturbed by collision with the wall of the intake port, and the turbulence in the gas flow in the combustion chamber is also increased to improve combustion. It depends on the reason.

Therefore, as described above, in the extremely low load region, the combustion chamber 11
By setting the sub control valve 41 on the side upright, the intake air flowing in from the upstream side of the intake manifold 5 first passes through the cutout portion 21 of the swirl control valve 23 in the same manner as in the first embodiment.
After that, it flows toward the notch 39 of the sub control valve 41 in the upright state (α = 0 °) and flows out to the combustion chamber 11 side. At this time, the sub control valve
The notch 39 of 41 has a smaller area than the notch 21 of the swirl control valve 23, and since the sub control valve 41 is in the upright state, the intake air flowing out of the notch 39 is partially in the inner wall of the intake port 3 as described above. While colliding, strong turbulence is generated and flows into the combustion chamber 11 through the opening 13. As a result, the turbulence of the gas flow in the combustion chamber 11 and the cycle fluctuation increase, the combustion speed increases, and significant combustion improvement can be achieved.

Next, when the load increases and reaches the partial load range, the sub control valve
Only 41 is opened and the intake air flows into the intake port 3 through the notch 21 of the swirl control valve 23. The flow of the intake air thereafter is substantially the same as that in the first embodiment. Therefore, in this case, uniform swirl with small turbulence and small cycle fluctuation adapted to the partial load region is generated, and a great improvement in combustion is achieved.

The swirl control valve 23 and the sub control valve are
Both 41 are fully opened, improving the intake charging efficiency.

As described above, in this embodiment, by providing two control valves, finer swirl control corresponding to the load state becomes possible.

17 and 18 show a fourth embodiment. This embodiment is a modification of the third embodiment and has two intake valves as in the case of the second embodiment. The intake port shape is a Siamese type and the openings 13a of the intake ports 3a, 3b to the combustion chamber 11 are formed. , 13b are formed. Also in this case, the swirl control valve 23 has the third
Like the second embodiment, it is tilted forward, and the position of the center of gravity of the cutout portion 21 is also the same as in the second embodiment. On the other hand, the sub-control valve 41 is not inclined when fully closed as in the third embodiment, and the cutout portion thereof is not formed.
The area of 39 is also smaller than the face of the notch 21 of the swirl control valve 23.

Therefore, even with the intake device configured as described above, as in the third embodiment, the combustion can be greatly improved in the extremely low load region and the partial load region. Further, in this case, both the swirl control valve 23 and the sub control valve 41 are fully opened in the full load range, and the intake air passes through the two intake ports 3a and 3b, so that the intake charge rate is further improved.

In the fourth embodiment, the notch portions 21 and 39 of the swirl control valve 23 and the sub control valve 41 are connected to the lower intake port 3b in the figure.
May be provided on the side, a dual port type in which the intake port shape is independent, or may be applied to an engine having two exhaust valves.

FIGS. 19 to 21 show fifth to seventh embodiments, respectively, in which the diameter of the combustion chamber side opening 13 of the intake port 3 and the diameter of the swirl control valve 23 are substantially the same. Is formed in. Therefore, in each of the fifth to seventh embodiments,
In the plan sectional view of the intake device as shown in FIGS. 19 and 20,
The center line 28 of the intake passage 14 and the intake port 3 of the four-divided portion 29
A line connecting the point on the farthest opposite side and the point C
Overlaps with.

In the fifth embodiment shown in FIG. 19, the intake port 3 and the exhaust port 5 are extended in the direction opposite to each other with respect to the combustion chamber 11, and both are arranged in a cylinder center line perpendicular to the cylinder row direction.
Located on the 18th. Therefore, in this case the control valve shaft 25
Of the central axis 26 of the and the outer circumference of the swirl control valve 23
Are located at substantially equal distances from the cylinder centerline 18. Therefore, the intake port 3 in the combustion chamber side opening 13
Of the two divided parts on the side opposite to the side, approximately 4 on the cylinder outer peripheral side
There are two divisions 29, and each notch 21 has four divisions 29.
Two are formed corresponding to.

The sixth embodiment shown in FIG. 20 is a so-called counter in which the intake port 3 and the exhaust port 5 are extended in the same direction, and the combustion chamber side openings 13 of the ports 3 and 5 are arranged in the cylinder row direction. A flow type engine to which the present invention is applied is shown.

In the seventh embodiment shown in FIG. 21, the intake passage 14 near the joint between the intake port 3 and the intake manifold 15 is inclined,
An application of this invention to an engine in which intake air is introduced obliquely from above is shown.

In each of the fifth to seventh embodiments, when the swirl control valve 23 is fully closed, the intake air smoothly flows out to the combustion chamber 11 side through the cutout portion 21, and the same effect as that of the first embodiment is obtained. .

EFFECTS OF THE INVENTION As described above, according to the present invention, (1) the arc of the substantially four-divided portion on the cylinder outer peripheral side among the two-divided portions on the side opposite to the intake port side in the combustion chamber-side opening of the intake port is formed. First
Of the first arc along the outer periphery of the control valve on the upper wall surface side of the intake passage from the intersection of the outer periphery of the control valve and the control valve shaft that is at least far from the cylinder center line perpendicular to the cylinder row direction. A second arc substantially equal to the flow is set, and the center of gravity of the cutout portion of the control valve is provided on the area of the control valve corresponding to the second arc, so that a uniform swirl is almost obtained until the latter half of the compression stroke. It is maintained without being damped, flame propagation proceeds stably, combustion is greatly improved, and fuel efficiency, emissions, and drivability can be greatly improved. (2) A low control load is provided because a notch having an area smaller than that of the notch of the control valve is provided downstream of the control valve, and the sub-control valve which is perpendicular to the center line of the intake passage when the valve is fully closed is provided. Due to the occurrence of intake turbulence in the region, and the sub-control valve is opened in the partial load region, a uniform swirl with little cycle fluctuation can both significantly improve combustion.

[Brief description of drawings]

1 to 11 relate to the first embodiment of the present invention,
FIG. 1 is a plan sectional view of the intake device, FIG. 2 is a view taken in the direction of arrow II in FIG. 1, FIG. 3 is a vertical sectional view of the intake device, and FIGS. 4 to 7 are specific cutout portions of the control valve. FIG. 8 is an explanatory view showing an example, FIG. 8 is an explanatory view showing the variation rate of the indicated mean effective pressure in the partial load region depending on the position of the notch, and FIG. 9 is an experiment corresponding to the view from the arrow direction in FIG. 3 IX. FIG. 10 is an explanatory view of the device, FIG. 10 is an explanatory view showing the fluctuation rate of the indicated fuel efficiency and the indicated average effective pressure depending on the air-fuel ratio, the 11th
The figure shows the gas flow characteristics with a laser Doppler velocimeter, No. 12
FIG. 13 is a plan sectional view of the air intake system of the second embodiment, and FIG.
FIG. 14 is a vertical sectional view of the embodiment, FIG. 14 is a plan sectional view of the intake device of the third embodiment, and FIG. 15 is a vertical sectional view of the third embodiment.
FIG. 16 is an explanatory diagram showing the fluctuation rate of the indicated mean effective pressure in the low load region depending on the position of the cutout portion, FIG. 17 is a plan sectional view of the intake device of the fourth embodiment, and FIG. 18 is the fourth embodiment. The same longitudinal section of the example,
FIG. 19 is a plan sectional view of the fifth embodiment, FIG. 20 is a plan sectional view of the sixth embodiment, and FIG. 21 is a longitudinal sectional view of the seventh embodiment. 3 ... intake port, 7 ... intake valve 11 ... combustion chamber, 13 ... opening 14 ... intake passage, 16 ... upper wall 18 ... cylinder center line, 21 ... notch 23 ... swirl control Valve, 25 ...... Control valve shaft 28 ...... Intake passage center line, 29 ...... 4-division part 30 ...... Vertical surface, 31 ...... Area part l ₁ ...... Length of first arc l ₃ ...... Length of the second arc, A, B ... Intersection

Claims (2)

[Claims] 1. A control valve having a cutout portion, which opens and closes an intake passage by rotation of a control valve shaft, is provided in the intake passage downstream of a throttle valve, and when the control valve is fully closed, the control valve is connected to the center line of the intake passage. Inclining forward to the intake valve side with respect to the vertical plane, and at the side opposite to the intake port side at the combustion chamber side opening of the intake port
An arc of approximately four divided parts on the outer peripheral side of the cylinder among the divided parts is defined as a first circular arc, and at the two intersections of the outer circumference of the control valve and the control valve shaft, from a cylinder center line perpendicular to the cylinder row direction. A second circular arc that is substantially equal to the length of the first circular arc along the outer periphery of the control valve on the upper wall surface side of the intake passage is set from an intersection located at a far position, and the control corresponding to the second circular arc is set. An intake system for an internal combustion engine, wherein the center of gravity of the cutout is provided on the area of the valve. 2. A sub-control valve is provided downstream of the control valve, the sub-control valve having a notch area smaller than the notch area of the control valve and being perpendicular to the center line of the intake passage when closed. An intake system for an internal combustion engine according to claim 1.