JPH08326546A - Variable engine intake pipe length - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an intake pipe length varying device for an engine with good controllability. [Structure] An intake manifold 5 having one end communicating with a combustion chamber and the other end communicating with a surge tank, one end opening 7 opening at a position facing the other end opening 6a in the surge tank 4, and the other end inside the surge tank. The communicating curved pipe 9 and the other end opening 6a or one end opening 7 of the intake manifold 5 extend toward the other opening so that the other end opening 6a or the one end opening 7 can be fitted to the other end, and the tip edge thereof is formed. A flange portion 18 that is formed to be inclined with respect to the axis, and the intake manifold 5 or the curved pipe 9 has the flange portion 18 and the other opening 6a fitted over the entire circumference thereof. The drive device 13 for variably setting the axial position of the one end opening 7 or the other opening 6a is provided so that the fitting between the other opening and the other opening is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for varying the intake pipe length of an engine, and more particularly, to a first and a second device in an intake passage constituting member of an intake system.
The present invention relates to an intake pipe length varying device for an engine, which is provided with a component for varying the amount of overlap of the intake passage pipes to vary the intake passage length.

[0002]

2. Description of the Related Art An intake system of an engine communicates between an intake port of the engine and an air intake port of an air cleaner, and interferes with an air cleaner, an intake pipe, a throttle body for adjusting an intake amount, and intake pulsations of other cylinders. It is configured by sequentially connecting intake system constituent members such as a surge tank and an intake manifold that branches intake air to each cylinder. The intake path length is determined by connecting these respective intake system constituent members to each other, and the length is basically constant.

By the way, it is known that the volumetric efficiency of an engine changes depending on the engine speed and the length of the intake pipe, which is considered to be due to the pulsation effect and the inertial effect of the intake pipe. Here, the pulsating effect is that the positive pressure wave generated in the intake port at the time of closing the intake valve returns as a positive pressure wave after reciprocating (twice) between the intake port and the atmospheric pressure equivalent portion side of the intake pipe. The inertial effect is caused by the inertia shown by the flow of the air column in the intake pipe. In either case, it is possible to expect the action of pushing the intake air into the cylinder, which can improve the volumetric efficiency.

Further, in a multi-cylinder engine, intake interference may occur between the intake passages of each cylinder, and in order to prevent this, the intake passages of each cylinder are branched from each other until a large capacity surge tank or the like is reached. Has been done. Here, intake interference is
A negative pressure wave generated when the intake valve opens opens through the intake passage and reaches the intake port of another cylinder just before the intake valve closes,
This is a phenomenon that reduces the volumetric efficiency of the cylinder. In this manner, the intake system of the engine is provided with the intake pipe variable mechanism that can positively utilize the intake pulsation in order to prevent intake interference and improve the engine volume efficiency.

For example, in the engine 1 shown in FIG. 9, its intake system extends from a plurality of intake passage constituent members, that is, the combustion chamber 2 and the intake port 3 of each cylinder, and the other end thereof is a surge tank 4
Of the intake manifold 5 (only one cylinder is shown) as a first intake passage pipe communicating with the surge tank 4, a surge tank 4 accommodating the protruding pipe 501 at the tip of these intake manifolds 5, and a protrusion in the surge tank 4. A curved pipe 9 serving as a second intake passage pipe having one end opening 7 opening at a position facing the other end opening 6 of the pipe 501 and the other end opening 8 protruding outside from the surge tank and communicating with the inside again. The surge tank 4 has one end and the intake pipe 11 communicates with the air cleaner 10 at the other end. Here, a throttle valve 17 is rotatably attached to each intake manifold 5. These intake system constituent members are connected to each other to determine the total intake path length, and the length thereof is basically constant.

Here, a straight portion 901 is formed at the lower end of the bending tube 9, and the extension tube 12 is fitted on the straight portion 901. The extension pipe 12 is provided with a drive device 13 which has a distal end-shaped opening 121 formed therein and which is brought into contact with and separated from the opening 502 on the side of the other end opening 6 of the protruding pipe 501. The driving device 13, the straight portion 901, and the straight portion 9
01 and the extension tube 12 fitted on the outside so as to form a trombone mechanism portion.

The driving device 13 has a first link 14a that is pin-connected to the outer peripheral wall of the extension tube 12, a second link 14b that is pin-connected to the other end of the first link 14a, and a second link 1.
A drive shaft 14c integrally connected to the pivot end of 4b and a DC motor 15 connected to the drive shaft 14c via a speed reducer (not shown) are provided, and the DC motor 15 is connected to a controller 16. The controller 16 drives the extension pipe 12 in accordance with the engine speed and controls the gap X between the opening 121 at the tip of the extension pipe 12 and the opening 502 of the protruding pipe 501.

Here, when the engine 1 is in the rotation range when the maximum output is generated, the controller 16 makes a gap X between the opening 121 of the extension pipe 12 and the opening 502 of the protruding pipe 501 in order to shorten the total intake pipe length. At the farthest position, and all of the airflow in the surge tank 4 is guided directly from the inlet 111 on the intake pipe 11 side to the other end opening 6 of the opening 502, and the effective intake pipe length is held at the minimum value Lso, and the maximum output To secure the pulsating effect of the intake pipe in the rotation range. On the other hand, when the engine 1 is in the rotation range when the maximum torque is generated, the opening 121 of the extension pipe 12 and the opening 502 of the protruding pipe 501 are brought into contact with each other in the surge tank 4 in order to increase the total intake pipe length. All of the air flow of (1) is guided to the other end opening 6 from the inflow port 111 through the curved pipe 9, and the effective intake pipe length is maintained at the maximum value Ls, and the pulsation effect of the intake pipe in the rotation range at the time of maximum torque generation is secured.

The effective intake pipe length in the surge tank 4 has a maximum value of Ls and a minimum value of Lso, but in order to secure an intermediate value in the meantime, a part of the air flow is guided to the other end opening 6 and the rest is left. Is guided to the other end opening 6 through the bending tube 9 from the other end opening 8. In this case, the ratio of the air flow rates of the other end opening 8 and the other end opening 6 is achieved by adjusting the gap X.

As shown in FIG. 8, when the clearance X is increased or decreased, the effective intake pipe length in the surge tank 4 is adjusted between the maximum value Ls and the minimum value Lso so that the clearance X becomes zero. When reaching the small gap area Xs, the effective intake pipe length increases rapidly, and the rate of change of the effective intake pipe length per unit gap increases rapidly.
The pressure loss μ shown by the broken line also increases sharply.

Here, when the gap X is in the small gap area Xs of FIG. 8, as shown in FIG. 10, the opening area of the flow path through which the air flow flows is obtained by multiplying the circumference of the two-dot chain line by the gap X. The outer peripheral length (circumferential length of the two-dot chain line) is large relative to the opening area. That is, m (= A) obtained by dividing the channel cross-sectional area A by the perimeter S.
/ S) is the fluid average depth, and the pressure loss is inversely proportional to the fluid average depth m. Therefore, here, the average fluid depth m is small, the pressure loss μ is large, and the intake flow resistance rapidly increases. An intake device for such an engine is disclosed in Japanese Utility Model Laid-Open No. 61-32521.

[0012]

As described above, the effective intake pipe length in the surge tank 4 has a maximum value Ls and a minimum value Lso.
When adjusting to increase or decrease between the gaps, especially the gap X is the small gap area Xs.
In the case of, the flow resistance of the air flow is large and the pressure loss μ increases rapidly, which causes the pulsation of the air flow. Moreover, in the small clearance region Xs, the rate of change of the effective intake pipe length per unit clearance change sharply increases, and controllability is likely to deteriorate, which is a problem. An object of the present invention is to provide an intake pipe length varying device for an engine with good controllability.

[0013]

In order to achieve the above object, the invention of claim 1 has a first intake passage pipe having one end communicating with a combustion chamber and the other end communicating with a surge tank, and one end having the surge tank. A second intake passage pipe that opens at a position facing the other end opening of the first intake passage pipe and has the other end communicating with the intake passage in the surge tank or on the upstream side of the surge tank; It is provided at either one of the other end opening of the intake passage or the one end opening of the second intake passage pipe and extends toward the other opening so as to be fitted into the other and the tip edge thereof is inclined with respect to the axis. And a flange portion formed so that the flange portion and the other opening are fitted over the entire circumference of the first intake passage pipe or the second intake passage pipe. The mating with the other opening is released As is the manner obtained, characterized in that the movable mechanism to variably set the axial position of the contrast aperture or other opening at.

The invention according to claim 2 is characterized in that the intake passage pipe having the above-mentioned collar portion is located inside and is fitted with the other intake passage pipe.

According to a third aspect of the present invention, the intake passage pipe having the collar portion is the first intake passage pipe.

The invention according to claim 4 is characterized in that the second intake passage pipe is made variable in the axial direction position by the movable mechanism.

The invention of claim 5 is characterized in that the intake passage pipe having the collar portion is the second intake passage pipe.

The invention of claim 6 is characterized in that the position of the first intake passage pipe in the axial direction is variable by the movable mechanism.

[0019]

According to the first aspect of the present invention, one end of the first intake passage pipe communicates with the combustion chamber at one end and the surge tank at the other end, and one end of the surge tank opens at a position facing the other end opening of the first intake passage pipe. And a second intake passage pipe having the other end communicating with the intake passage in the surge tank or on the upstream side of the surge tank, and in particular, the other end opening of the first intake passage or the second intake passage pipe.
A flange is provided on one of the openings on one end of the intake passage pipe, and the flange extends toward the other opening so that the flange can be fitted into the other and the tip edge of the flange is inclined with respect to the axis. The first intake passage pipe or the second intake passage pipe is provided with a movable mechanism, whereby the flange portion and the other opening are fitted over the entire circumference thereof, and the flange portion and the other opening are formed. The axial position of the one opening or the other opening is variably set so as to obtain a mode in which the fitting is released. For this reason, the rate of change of the effective intake pipe length per unit gap change becomes relatively small in the small gap region.

According to the second aspect of the present invention, the intake passage pipe having the flange portion is located inside and is fitted with the other intake passage pipe, and in this case as well, the effective intake pipe length per unit gap change in the small gap area is set. The rate of change is relatively small.

According to the invention of claim 3, the intake passage pipe having the flange portion is the first intake passage pipe, and in this case as well, the rate of change of the effective intake pipe length per unit gap change is relatively small in the small gap region. .

According to the fourth aspect of the present invention, the second intake passage pipe has a variable axial position due to the movable mechanism. Therefore, in this case as well, the rate of change of the effective intake pipe length per unit gap change is relatively small in the small gap area. Get smaller.

According to the invention of claim 5, the intake passage pipe having the flange portion is the second intake passage pipe, and in this case as well, the rate of change of the effective intake pipe length per unit gap change is relatively small in the small gap region. .

According to the sixth aspect of the present invention, the position of the first intake passage in the axial direction is variable by the movable mechanism.
In the small gap area, the rate of change of the effective intake pipe length per unit gap change becomes relatively small.

[0025]

1 shows an intake pipe length varying device A for an engine as an embodiment of the present invention.

Compared with the intake pipe length varying device A of the engine shown in FIG. 9, this intake pipe length varying device A has many of the same members except that the pipe line constituent members in the surge tank 4a are partially different. Here, the same members are denoted by the same reference numerals, and duplicate description is omitted.

The intake pipe length varying device A is installed in an in-line four-cylinder engine (hereinafter simply referred to as an engine) 1, and the intake system of the engine 1 has an air cleaner 10, an intake pipe 11, a surge tank 4a, and an intake manifold with a throttle valve 17. The total intake pipe length, which is the total intake path of the engine 10, is determined by sequentially connecting the intake system constituent members such as the pipe 5 and the intake port 3, and the length is the maximum value Ls and the minimum value in the surge tank 4a. Adjustment is made within the range of the value Lso. FIG.
As shown in FIG. 4, the surge tank 4a has a capacity capable of interfering the intake pulsation of each cylinder, and in particular, accommodates a main part of the intake pipe length varying device A of the engine.

The surge tank 4a accommodates the ejection pipe 501 at the tip of the intake manifold 5, and furthermore, the ejection pipe 501.
A curved pipe 9 as a second intake passage pipe having one end opening 7 opening at a position facing the other end opening 6 and the other end opening 8 protruding outside from the surge tank and communicating with the inside again; Is provided with an inlet 111 at one end of an intake pipe 11 communicating with the air cleaner 10. Here, the extension tube 12 is fitted onto the straight portion 901 at the lower end of the bending tube 9. Extension tube 12
A drive device 13 is mounted on the drive device 13 and the opening 121 at the tip of the drive device 13 and the opening 502 on the other end opening 6 side of the protruding pipe 501 are operated to come into contact with and separate from each other. A base portion is integrally coupled to the inner peripheral wall of the opening portion 502 of the protruding pipe 501, and a flange portion 18 protruding from the inclined opening 6a that is cut at an inclination is provided.

The outer diameter D1 of the collar portion 18 is smaller than the inner diameter d1 of the extension tube 12 (see FIG. 3), so that both can be fitted smoothly.

Here, when the opening 121 of the extension pipe 12 is at the most retracted retreat position E1, as shown in FIGS. 1 and 2, the opening tip of the flange 18 is separated from the gap Q1 and the flange 18 is opened.
The rear end of the opening is set to be separated from the gap Q2. On the other hand, when the opening 121 of the extension tube 12 is at the most protruding position E2, the inclined opening 6a of the flange 18 is set to be completely covered by the opening 121 of the extension tube 12, as shown in FIG. To be done.

Here, the drive device 13, the straight portion 901 and the extension tube 12 are constructed so as to form a trombone mechanism portion.

The drive unit 13 includes a first link 14a and a second link 14a.
The DC motor 1 includes a link 14b, a drive shaft 14c integrally connected to the second link 14b, and a DC motor 15.
5 is connected to the controller 16a. Controller 1
6a drives the extension tube 12 according to the engine speed, and the opening 121 at the tip of the extension tube 12 and the opening 50 of the protruding tube 501.
Contact and separation between 2 and. Here, when the engine 1 is in the rotation range when the maximum output is generated, the controller 16a separates the gap between the opening 121 of the extension pipe 12 and the opening 502 of the protruding pipe 501 so as to shorten the total intake pipe length, The slanted opening 6a of the collar portion 18 is fully opened, and all of the airflow in the surge tank 4 is guided directly from the inflow port 111 to the slanted opening 6a.
The effective intake pipe length is maintained at the minimum value Lso to secure the pulsating effect of the intake pipe in the rotation range when the maximum output is generated.

At this time, as shown in FIG. 5, the gap Q
2 is large, the opening area of the flow path where the air flow flows is the area of the circle of the two-dot chain line e, the outer peripheral length (circumferential length of the two-dot chain line e) is small for the opening area, and the intake flow resistance Is small,
The pressure loss μ is low (see FIG. 7). On the other hand, when the engine 1 is in the rotation range when the maximum torque is generated, the opening 121 of the extension pipe 12 reaches the most protruding position E2 in order to increase the total intake pipe length, and as shown in FIG. The inclined opening 6a of the portion 18 is completely covered by the opening 121 of the extension tube 12. Here, all of the air flow in the surge tank 4 is the inlet 1
11 leads to the flange portion 18 side through the bending pipe 9, maintains the effective intake pipe length at the maximum value Ls, and secures the pulsating effect of the intake pipe in the rotation range when maximum torque is generated.

At this time, the inclined opening 6a is completely covered,
There is no inflow airflow from the inclined opening 6a, and as shown in FIG. 7, the intake flow resistance is smaller than that of the device of FIG. 9 and the pressure loss μ is relatively low. Next, when the engine 1 is in the rotation range when the intermediate output is generated, the controller 16a creates a gap between the opening 121 of the extension pipe 12 and the opening 502 of the protruding pipe 501 in order to set the total intake pipe length to the intermediate length. Bring it closer by a predetermined amount. At this time, as shown in FIGS. 3 and 6, the inclined opening 6a of the collar portion 18 has a crescent shape in bottom view, and the surge tank 4
Part of the air flow inside is sucked in through the crescent-shaped inclined opening 6a,
The other part is sucked through the bending tube 9.

As a result, the effective intake pipe length is held at an intermediate value between the minimum value Lso and the maximum value Ls, and the pulsating effect of the intake pipe in the intermediate rotation range can be secured. At this time, as shown in FIG. 6, there is a gap between Q1 and Q2,
The opening area of the flow path of the air flow is the curved crescent shaped area of the two-dot chain line f in FIG. 6 (a), and the outer peripheral length (the outer circumferential length of the curved crescent shape f of the two-dot chain line) is calculated for the opening area. ) Is small. That is, the fluid average depth m (= A / S) obtained by dividing the flow path cross-sectional area A by the peripheral length S is relatively large, and the pressure loss is relatively small. Therefore, here, the pressure loss μ is relatively small,
Intake flow resistance is relatively small (see the broken line in FIG. 7).

Particularly, at this time, even if the clearance Q reaches the small clearance area q close to zero, the rate of change of the effective intake pipe length per unit clearance is maintained as in the outside of this area, and the controllability is deteriorated. Can be prevented. In the above-described intake pipe length varying device A, the intake manifold 5 which is the first intake passage pipe has the collar portion 18, and the second
The extension pipe 12 on the curved pipe 9 side as an intake passage pipe was fitted on the outside. Instead of this, as a modified example of the intake pipe length varying mechanism A, the extension pipe as the second intake passage pipe is provided with the flange portion, and the extension pipe of the intake manifold, which is the first intake passage pipe, is externally fitted to this. You may take a structure. Also in this case, the same effect as that of the device of FIG. 1 can be obtained.

[0037]

According to the invention of claim 1, one end of the first intake passage pipe communicates with the combustion chamber and the other end communicates with the surge tank, and one end of the surge tank faces the opening of the other end of the first intake passage pipe. And a second intake passage pipe having the other end communicating with the intake passage in the surge tank or on the upstream side of the surge tank, and particularly, the other end opening of the first intake passage or one end of the second intake passage pipe. A flange portion is provided in one of the openings, and the flange portion is formed to extend toward the other opening so that the flange portion can be fitted into the other and the tip edge thereof is inclined with respect to the axis. A movable mechanism is provided, whereby the first intake passage pipe or the second intake passage pipe is fitted with the flange portion and the other opening over the entire circumference, and the fitting of the flange portion and the other opening is released. And one of the The axial position of the mouth or other opening to variably set. Therefore, the change rate of the effective intake pipe length per unit gap change becomes relatively small in the small gap area,
Controllability is improved.

According to the second aspect of the present invention, the intake passage pipe having the flange portion is located inside and is fitted with the other intake passage pipe. In this case as well, the effective intake pipe length per unit gap change in the small gap area is set. The rate of change is relatively small and the controllability is further improved.

In the third aspect of the present invention, the intake passage pipe having the flange portion is the first intake passage pipe, and in this case as well, the change rate of the effective intake pipe length per unit gap change is relatively small in the small gap area. , The controllability is improved.

According to the invention of claim 4, since the second intake passage pipe has its axial position variable by the movable mechanism, the rate of change of the effective intake pipe length per unit gap change in the small gap region is relatively large in this case as well. It becomes smaller and the controllability is improved.

According to the fifth aspect of the present invention, the intake passage pipe having the flange portion is the second intake passage pipe, and in this case as well, the change rate of the effective intake pipe length per unit gap change is relatively small in the small gap area. , The controllability is improved.

According to the sixth aspect of the invention, the position of the first intake passage in the axial direction can be changed by the movable mechanism.
In the small gap area, the rate of change of the effective intake pipe length per unit gap change becomes relatively small, and the controllability is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an intake pipe length varying device for an engine as an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the trombone mechanism portion of the intake pipe length varying device of FIG. 1 when it is fully opened.

FIG. 3 is an enlarged cross-sectional view of the trombone mechanism portion of the intake pipe length varying device of FIG. 1 at an intermediate opening degree.

FIG. 4 is an enlarged cross-sectional view of the trombone mechanism portion of the intake pipe length varying device of FIG. 1 in a fully closed state.

FIG. 5 is a diagram illustrating flow resistance characteristics when the trombone mechanism of the intake pipe length varying device of FIG. 1 is fully opened.

FIG. 6 is a diagram for explaining the flow resistance characteristic at the intermediate opening of the trombone mechanism portion of the intake pipe length varying device of FIG.
(A) is a bottom view and (b) is a side view.

7 is a characteristic diagram of an effective intake pipe length and a clearance of the intake pipe length varying device of FIG.

FIG. 8 is a characteristic diagram of an effective intake pipe length and a clearance of a conventional intake pipe length varying device.

FIG. 9 is an overall configuration diagram of a conventional intake pipe length varying device.

FIG. 10 is a diagram illustrating a flow resistance characteristic near the fully closed state of the trombone mechanism portion of the conventional intake pipe length varying device. 1 Engine 4a Surge Tank 5 Intake Manifold 501 Extruded Pipe 502 Opening 6a Inclined Opening 7 One End Opening 9 Curved Pipe 10 Air Cleaner 11 Intake Pipe 111 Inlet 12 Extension Pipe 121 Opening 13 Drive 18 Collar A Intake Pipe Length Changing Device Ls Maximum value Lso Minimum value Q1 Gap Q2 Gap

Claims (6)

[Claims] 1. A first intake passage pipe having one end communicating with a combustion chamber and the other end communicating with a surge tank, and one end opening at a position facing the other end opening of the first intake passage pipe in the surge tank and the other. Any one of a second intake passage pipe whose end communicates with the intake passage in the surge tank or on the upstream side of the surge tank, and the other end opening of the first intake passage or one end opening of the second intake passage pipe. A flange portion which is provided on one side and extends toward the opening on the other side so as to be fitted to the other side, and a front end edge of which is formed so as to be inclined with respect to the axis line; The two intake passage pipes are provided with the above-mentioned one side so that the flange portion and the other opening can be fitted over the entire circumference thereof and the flange portion and the other opening can be released from each other. Axial direction of opening or other opening An intake pipe length varying device for an engine, comprising a movable mechanism for variably setting a facing position. 2. The intake pipe length varying device for an engine according to claim 1, wherein the intake passage pipe having the flange portion is located inside and is fitted to the other intake passage pipe. 3. The intake pipe length varying device for an engine according to claim 1, wherein the intake passage pipe having the collar portion is the first intake passage pipe. 4. The intake pipe length varying mechanism according to claim 1, wherein the second intake passage pipe has the axial position variable by the movable mechanism. 5. The intake pipe length varying device for an engine according to claim 1, wherein the intake passage pipe having the collar portion is the second intake passage pipe. 6. The intake pipe length varying mechanism according to claim 1, wherein the first intake passage pipe is configured to change the axial position by the movable mechanism.