JPH02223632A - Intake system for multi-cylinder internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an intake system for a multi-cylinder internal combustion engine in which the length of an intake pipe is changed depending on the rotational speed range of the engine.

(Prior art) The intake inertia effect is used as a means to improve the output of an internal combustion engine, but since the intake pressure wave propagates at the speed of sound in the intake pipe, the length of the intake pipe changes depending on the engine speed. Unless the value is changed, the intake inertia effect cannot be effectively used in the entire speed range.

Therefore, a proposal has been made to change the length of the intake pipe by providing an extension pipe at the end of the intake pipe that can be moved toward and away from the intake pipe, and making this extension pipe move toward and away from the intake pipe depending on the engine speed.
(Refer to Utility Model Publication No. 59-7537).

(Problem to be Solved by the Invention) However, in the intake device according to the above proposal, the link lever is moved via the wire by lever operation, and the movement of the link lever causes the extension pipe to connect to the intake pipe. This makes the structure complicated, and especially when the engine has multiple cylinders, it is difficult to simultaneously move the extension pipes toward and away from the intake pipes with good responsiveness.

The present invention has been made in view of the above problems, and its purpose is to provide an intake system for a multi-cylinder internal combustion engine that has a simple structure, has good responsiveness, and can change the length of all intake pipes at the same time. It is on offer.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a plate that integrally supports a plurality of extension pipes that are movable with respect to the intake pipes connected to each cylinder of a multi-cylinder internal combustion engine. In addition, an intake system for a multi-cylinder internal combustion engine is configured by providing an actuator that drives the plate and a controller that controls the operation of the actuator in accordance with the engine speed.

(Function) According to the present invention, the controller controls the operation of the actuator according to the engine speed, and the actuator drives the plate that integrally supports the plurality of extension pipes. It moves responsively and simultaneously with respect to the pipes, thereby changing the length of all intake pipes simultaneously.

In addition, as the actuator, a cylinder that operates with negative intake pressure, a servo motor that is easy to control, etc. can be used.
The structure of the intake device, particularly the drive mechanism of the extension pipe, can be simplified.

(Example) An example of the present invention will be described below based on the accompanying drawings.

Figures 1 and 2 are longitudinal cross-sectional views showing the state of the intake system in the high-speed and low-speed ranges of the engine, respectively (A-A in Figure 3).
FIG. 3 is a side view of the essential parts of a motorcycle equipped with the intake system, and FIG. 4 is a graph showing the performance characteristics of the engine.

First, the general structure of the engine surroundings of a motorcycle will be explained based on Fig. 3. In the figure, l is a head vibrator located at the front of the vehicle body, and behind the head vibrator are two main frames on the left and right. 2.2 are extended, and a water-cooled four-cylinder engine 3 is supported by these main frames 2.2.

An intake system 10 according to the present invention is connected to the intake system of the engine 3, and an exhaust pipe (not shown) leads out from the exhaust system.

In the intake system M10, 1i is an intake duct that opens into the atmosphere at one end, and an intake box 12 housed in the tank cover 5 is connected to the intake duct 11. The four intake pipes 13 connected to intake passages (not shown) formed in each cylinder of the engine 3 are open at one end, and each intake pipe 1
A carburetor 4 is interposed in the middle of 3.

As shown in Fig. 141, the intake pipes 13 are arranged in parallel in the left-right direction of the vehicle body (perpendicular to the plane of the paper in Fig. 3), and each opening end has a bell-mouth shape. Aluminum funnels 14 having openings are connected, and these funnels 14 are connected and integrally fixed by one plate 15. And, in the vicinity of these funnels 14..., resin extension pipes 16... that can be attached to each of them are arranged, and these are integrally supported by one play)-17. has been done.

Note that one end (upper end) of each extension tube 16 is connected to the funnel 14.
It forms a bellmouth-shaped opening, similar to the opening in . Further, each extension tube 16 is slidably inserted into each circular hole 17a bored in the plate 17.
As shown in FIG. The extension tube 16... is the funnel 14...
- When they are far apart, the step portion 16a formed on the outer periphery of the plate 17 rests at a position where it comes into contact with the plate 17. Therefore, in the state shown in FIG.
... can move together with the plate 17.

Further, a cylinder 20 is installed in the center of the plate 15, and a round guide bar 2 is installed at the negative end of the plate 15 (between the two funnels 14 and 14 on the right).
1 is attached perpendicularly to the surface, and the guide bar 21
is slidably passed through a circular hole 17b bored in the plate 17.

By the way, a piston 23 is fitted into the body 22 of the cylinder 20 so as to be slidable in the direction of engagement and separation of the extension tubes 16 (vertical direction in FIG. 1).
2, there are chambers S, , S defined by the piston 23.
(see Figure 2) is formed. The cylinder body 22 has a chamber S+, a boat 24.
25 are formed respectively, and these boats 24.2
5 are connected to a solenoid type switching valve 28 via a vibrator 26, 27, respectively, and the switching valve 28 is connected to the intake system of the engine 3 (see FIG. 3) via a vibrator 29. Further, a controller 30 such as a microcomputer that detects the rotational speed N of the engine 3 and controls the operation of the switching valve 28 is electrically connected to the switching valve 28 .

On the other hand, a rod 31 integrally extends upward from the piston 23 of the cylinder 20, and the center portion of the plate 17 is screwed into the end of the rod 31 with a nut 32.

Next, the operation of the intake device 10 will be explained.

When the engine 3 is started, fresh air is sucked by the cranking negative pressure generated in each cylinder of the engine 3 through the intake duct 11 shown in FIG. 3 and introduced into the intake box lz.

By the way, if the engine rotation aN is lower than the predetermined value N0 (N
<N,) In the low rotation range, the controller 30 switches the switching valve 28 to the vibrator 27 side and directs the intake negative pressure generated in the engine 3 to the chamber S in the cylinder 20 through the vibrator 29, 27 and the boat 25. As a result, as shown in FIG. 2, the piston 23 of the cylinder 20 is pulled down by the negative intake pressure and moves the plate 17 toward the funnel 14 via the rod 31. At this time, the plate 17 moves while being guided by the guide bar 21, and the guide bar 21 prevents the plate 17 from twisting.

When the plate 17 moves in this way, the brake 1-1
The extension tubes 16 integrally supported by the funnels 14 also move in the same direction and come into contact with the openings of the funnels 14 at substantially the same time and are connected thereto. The stroke of the piston 23 is set so that the plates 1 to 17 move somewhat even after contacting the extension tube 16 or the funnel 14. As a result, the splinters 19 and 17 move slightly. ... are compressed, and the extension tube 16 ... is compressed by these springs 19 ...
It is pressed against the funnel 14 with a predetermined pressure by the elastic force of. In addition, these springs 19 absorb dimensional errors in the extension tubes 16, funnels 14, etc., and the entire extension tube 16 can be adjusted without strict control of the dimensional accuracy between each part. can be brought into pressure contact with the funnel 14...

Therefore, as mentioned above, the extension tube 16 becomes the funnel 14...
As a result, the length of the intake pipes 13-- becomes longer by the amount Δ shown in the figure, and the fresh air introduced into the intake box 12 is transferred to the extension pipes 6-- as shown in FIG. It is introduced into the intake pipe L3-... from the opening of. A mixture is formed by the carburetor 4 in the middle of each intake pipe 13, and this mixture is supplied from each intake pipe 13 to each cylinder of the engine 3 for combustion, and exhaust gas is generated by the combustion of this mixture. Gas is discharged into the atmosphere from each exhaust pipe 4.

In this low rotation range, as mentioned above, the intake pipe 13...
- As a result of setting the length to be long, an effective intake inertia effect can be obtained, and the output of the engine 3 can be improved.

On the other hand, the rotation speed N of the engine 3 is a predetermined value N. exceeding (N
>No) In the high rotation range, the controller 30 switches the switching valve 28 to the vibrator 26 side and guides the intake negative pressure generated in the engine 3 to the chamber S in the cylinder 20 via the vibrator 29, 26 and the boat 24. Then, cylinder 2
As shown in FIG. 1, the piston 23 of No. 0 is moved upward by the intake negative pressure, and the plate 17 is moved upward together with the extension tube 16 via the rod 31. As a result, the extension tube 16
-... are separated from the funnels 14 with good response and at the same time, as shown, and the lengths of the intake pipes 13 are set short. In addition, since the opening of the funnel 14 is formed in a bell mouth shape as described above, the extension tube 1
The opening area of each of the funnels 14 can be greatly changed by a slight movement of the funnels 14 .

Thus, the fresh air introduced into the intake box 12 is sucked into the intake pipe 13 through the opening of the funnel 14, and an effective intake inertia effect is obtained even in this high rotation range. Efforts are being made to improve the output of engine 3.

As mentioned above, the intake pipe 13...
・By changing the length, an effective intake inertia effect can be obtained in both rotations, and the conventional intake device t shown by the chain line in Fig. 4 (an intake device in which the length of the intake pipe remains unchanged)
In contrast to the performance characteristics of an engine having ) is obtained. Furthermore, in this embodiment, since the extension pipes 16 are integrally supported by a single plate 17, the length of the intake pipes 13 can be changed simultaneously with good response. The intake system is particularly effective for multi-cylinder internal combustion engines.

Furthermore, in this embodiment, since the cylinder 20 operated by the intake negative pressure generated in the engine 3 is adopted as the actuator for driving the play plate 17, the structure of the drive mechanism of the intake device 10, especially the extension pipe 16... Simplification can be achieved. Note that similar effects can be obtained by using an easily controllable servo motor or the like as the actuator.

Next, another embodiment of the present invention will be described based on FIGS. 5 to 1O. In addition, FIG. 5 is a cutaway side view showing an intake device according to another embodiment, FIG. 6 is a perspective view of the main part of the same intake device, and FIG.
Figures 1 through 10 are cross-sectional views showing the state of the intake device (extension pipe) in each engine speed range.

In the intake system 110 shown in FIG. 5, reference numeral 112 denotes an intake box whose one end is open to the atmosphere, and inside the intake box 112 there are 4 cylinders connected to an intake passage formed in a four-cylinder engine (not shown). One end of each intake pipe 113 is open, and a carburetor 104 is interposed in the middle of each intake pipe 113.

The intake pipes 113 are arranged in parallel in the left-right direction of the vehicle body (perpendicular to the plane of the paper in FIG. 5), and each intake pipe 113 has a bell-mouth-shaped opening at the open end as shown in FIG. A funnel 114 having a section is connected. The four funnels 114 provided for each cylinder are integrally connected by one base plate 115, as shown in FIG.

By the way, as shown in FIG.
A telescopic extension tube 118 is attached to the outer periphery of the tube 118 so that the inner circumference of the lower end thereof is slidably fitted. The extension tube 116 is a concentric cylindrical tube 116a in two stages, upper and lower, which are slidably connected.

116b, and the inner circumference of the lower end of the upper cylindrical tube 116a is slidably fitted to the outer circumference of the lower cylindrical tube 116b. Incidentally, the periphery of the upper end opening of these cylindrical tubes 116a and 116b is formed into a bell mouth shape, and one cylindrical tube 11
A stopper 116a-1 protrudes from the inner periphery of the lower end of the tube 6a, and stoppers 116b-1 and 116b-2 protrude from the outer periphery of the upper end and the inner periphery of the lower end of the two cylindrical tubes 116b, respectively. Further, a circlip 140 is fitted to the outer periphery of the lower end of the cylindrical tube 116b.

As shown in FIG. 6, the fourteen extension tubes 116 are connected to the body weight through plates 117a, 1" 17b, and 117c, and are connected to the two guide bars erected on the base plate 115. 121°121 slidably passes through the plates 117a and 117c, respectively, to connect the plates 117a and 117c.

It protrudes above 117c. And guide bar 1
21,121 base plate 115 and plate 117
There is a return spring 11 in the part between a and 1i7c.
．． 9,119 are packed, and due to the small force of these return strings 7119, 119, the entire extension of pipe 1
i6... is always biased in the direction of extension.

In addition, a bracket 1 is provided at the center of the base plate 115.
41 is attached, and a control wire 144 is wound around a pulley 143 which is rotatably supported on the bracket 141 by a pin 142. One end of this control wire 144 is connected to the play plate 117b, and the other end passes through the intake box 112 and extends outside of the air intake box 112, as shown in FIG. 5, and is connected to the servo motor 120. has been done. still.

The servo motor 120 includes a controller 1 that controls the rotation of the servo motor 120 according to the engine rotation speed N.
30 or electrically connected.

Therefore, in the low engine speed range where the engine speed N is small, the extension pipes 116 are in the most extended state and have the longest length as shown in FIG. 7, so that an effective intake inertia effect is achieved. is obtained, and the output direction of the engine can be estimated.

On the other hand, in the high engine speed range where the engine speed N is large,
Controller 130 drives servo motor 120, and control wire 144 is pulled by driving servo motor 120. Then, the plates 117a, 1
17b.

Extension pipe 116 connected and integrally fixed by 1Z7c...
・2 The cylindrical pipes 116a-, 116b resist the elastic force of the return springs 119, 119, and the intake pipe 113.
... slides toward the side, and reaches the most contracted state as shown in FIG. becomes. As a result, an effective intake inertia effect can be obtained even in a high rotation range, and the output of the engine can be improved. 2. When the extension tube 116 shown in Fig. 1O is in its most contracted state,
Intake pipe 1132 cylindrical pipe 116a.

The upper end openings of 116b are joined together to form one continuous bell mouth shape.

In the medium speed range other than the above, the controller 1
30 is for controlling the rotation of the servo motor 120 according to the engine rotation speed N at that time.

The length of the extension tube 116... can be arbitrarily and continuously changed, for example, as shown in FIG.
... is set to a length that provides an effective intake inertia effect. In addition, since the circlip 140 is fitted to the outer circumference of the lower end of the cylindrical tube 116b below each extension tube 116, when the cylindrical tube 116b slides, the circlip 140 has a hill side as shown in FIG. The lower ends of the cylindrical pipes 116a abut against each other, and as a result, the cylindrical pipes 116b reliably slide along the outer periphery of the intake pipes 113.

In the fifth embodiment as well, the length of the extension tube 116 can be changed simultaneously with good response, but in particular in this embodiment, the length of the extension tube 116 can be changed continuously. Optimal extension tube 1 for the engine speed at that time
16... can be obtained, and a more effective intake inertia effect can be obtained.

(Effects of the Invention) As is clear from the above description, according to the present invention, a plurality of extension pipes movable with respect to the intake pipe connected to each cylinder of a multi-cylinder internal combustion engine are integrally supported by a plate. With,
The intake system for a multi-cylinder internal combustion engine is configured by providing an actuator that drives the plate and a controller that controls the operation of the actuator according to the engine speed, so it has a simple structure, has good responsiveness, and can simultaneously control all intake pipes. The effect is that the length can be changed.

[Brief explanation of the drawing]

Figures 1 and 2 are longitudinal cross-sectional views showing the state of the intake system in the high-speed and low-speed ranges of the engine, respectively (A-A in Figure 3).
3 is a side view of the essential parts of a motorcycle equipped with the same intake device, FIG. 4 is a graph showing the performance characteristics of the engine, and FIG. 5 is an intake device according to another embodiment of the present invention. A broken side view, Figure 6 is a perspective view of the main parts of the intake system, and Figures 7 to 10 are the intake system (extension pipe) in each engine speed range.
FIG. ■...Multi-cylinder engine, 13,113...Intake pipe. 16.116--Extension tube, 17,117a. 117b, 117c...Plate, 20...Cylinder (actuator), 120...Servo motor (actuator), 30, 130-...Controller. Figure 7 Figure 9 Figure 8

Claims (3)

[Claims] (1) A plate integrally supports a plurality of extension pipes that are movable with respect to the intake pipe connected to each cylinder of a multi-cylinder internal combustion engine, and an actuator that drives the plate and an actuator that drives the actuator. An intake system for a multi-cylinder internal combustion engine, comprising a controller that performs control according to engine speed. (2) The intake system for a multi-cylinder internal combustion engine according to claim 1, wherein the extension pipe is movable towards and away from the intake pipe, and these are integrally supported by a single plate. . (3) Each of the extension pipes is a telescopic structure composed of a plurality of concentric cylindrical pipes that are slidably connected, and one end of each extension pipe is slidably fitted to the outer periphery of each of the intake pipes. An intake system for a multi-cylinder internal combustion engine according to claim 1.