JPS5856329Y2 - Internal combustion engine intake inertia pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of an intake inertia pipe that improves the intake inertia effect in an internal combustion engine.

Conventionally, in an internal combustion engine, an intake inertia pipe that is connected to an intake port provided in a cylinder head to introduce intake air has been used. For example, in a multi-cylinder engine, each cylinder's intake pipe is an independent intake system, and each intake pipe is It is known that it is effective to improve the intake inertia effect and increase the volumetric efficiency by setting the lengths to be equal and to an optimal length within a constraint range around the set position.

As a means of obtaining the optimal intake pipe length according to the rotational speed, for example, as shown in Utility Model Application No. 49-64611, a pipe length adjustment pipe that can be freely moved in and out from the outside on the suction side of the intake pipe is used. There is one in which the length adjusting pipe is moved in and out as appropriate to obtain the optimum intake pipe length depending on the rotational speed.

With this kind of structure, high output can be produced over a wide range of rotations from low speed to high speed, but
However, if it is attempted to perform adjustment from high-speed rotation to low-speed rotation using this tube length adjustment tube, the range of movement in and out of the tube length adjustment tube, that is, the sliding range will naturally become longer.

On the other hand, in a configuration with such an intake inertia pipe,
It has the disadvantage of increasing noise due to air column vibration in the intake pipe,
To this end, it is necessary to provide an expansion chamber with an intake silencer at the inlet end of the intake inertia pipe.

In this case, if a pipe length adjustment pipe is provided, the pipe length adjustment pipe will be placed inside this intake silencer, but as mentioned above, the entire range from low speed to high speed can be controlled by moving in and out of the pipe length adjustment pipe. In systems where the output is adjusted to the maximum, there is a drawback that sufficient space cannot be taken for the entrance and exit of the pipe length adjustment pipe unless the intake silencer is made larger than necessary.

The present invention eliminates these drawbacks and limits the adjustment range of the intake pipe length by the pipe length adjustment pipe to the medium speed rotation range that is most often used when working on fishing boat engines. The inlet/outlet range of the pipe is kept as short as possible, and on the other hand, for high-speed rotations that are widely used, the intake pipe is branched to form another short intake passage, and a shutter provided at the branch part is used to The intake passage can be switched between high speed and medium speed, which allows the intake silencer to be constructed compactly as a whole without increasing its size.

DETAILED DESCRIPTION OF THE INVENTION The configuration of the present invention will be described below based on a drawing showing an embodiment implemented in a three-cylinder internal combustion engine.

First, in FIGS. 1 and 2, each intake pipe 1, 1.1, which is designed to be independent and have the same length, has one end connected to each cylinder 2a, 2b provided in the cylinder head.
, 2C is communicatively connected to an intake port (not shown) of
Its tip is suspended while avoiding the fuel pump 3 and generator 4, and is connected to the base end of a fixed pipe 7 inserted into an intake silencer 6 having an intake hole 5. The pipe 7 constitutes a part of the intake pipe 1.

The fixed pipe 7 is provided with branch pipes 8 in the middle thereof to branch in two directions, and a switching shutter 10 fixed to a switching shaft 9 is disposed inside the branch part to switch the switching. A long main suction passage 11 on the fixed pipe 7 side due to the shutter 10
A and one of the short sub suction passage 11b on the side of the branch pipe 8 are selectively opened.

The switching shutter 10 is configured to be automatically switched when the rotational speed of the internal combustion engine reaches a certain level by means of a solenoid valve (not shown) or the like that is operated by a signal from an appropriate device that detects the rotational speed of the internal combustion engine.

Next, a tube length adjusting tube 12 is slidably fitted onto the open end of the fixed tube 7, and the tip of the tube length adjusting tube 12 protrudes from the fixed tube 7 and opens in a trumpet shape.

Reference numeral 13 denotes a fixing bolt which is screwed onto the length adjusting tube 12 from the outside and has its tip pressed against the fixing tube 7. In order to set the main suction passage 11a to an appropriate length,
is fixed in an appropriate position.

Now, in the above configuration, the function of the intake inertia pipe in the embodiment of the present invention will be explained below based on the diagram of FIG. 4 in which the vertical axis shows the volumetric efficiency η and the horizontal axis shows the rotational speed N. do.

In FIG. 3, the diagram H1 shows the case where the branch pipe 8 side is opened and the intake pipe length H1 of the auxiliary intake passage 11b is used,
The volumetric efficiency η is shown when the engine speed is matched to be maximum when the engine speed is N1.

Furthermore, diagrams H2 and H3 show the case where the branch pipe 8 side is closed and the main suction passage 11a is used, and N2 is set to a relatively short intake pipe length H2 fixed with the pipe length adjustment pipe 12 pushed in. The diagram H3 shows the volumetric efficiency η when matched to the medium speed rotation N2, and the diagram H3 shows that the longest intake pipe length H3 is set by protruding the pipe length adjustment pipe 12, and the medium speed rotation N3 is lower than N2. The graph shows the change in η7 when the values are matched.

Note that switching between the main suction passage 11a and the auxiliary suction passage 11b is performed at the rotation speed N.

It is supposed to be done in time.

As shown in this diagram, in the intake inertia pipe according to the embodiment of the present invention, the intake pipe length H1 is used at high speed rotation N1, the intake pipe length H2 is used at medium speed rotation N2, and the intake pipe length H2 is used at medium speed rotation N3. By using the intake pipe length H3, compared to using other intake pipe lengths, A
The volumetric efficiency is improved by η, and the highest volumetric efficiency suitable for each rotation speed can be obtained.

Therefore, according to the present invention, the intake pipe length H1 is set during normal sailing, the intake pipe length H2 is set during fishing or work using medium speed rotation N2, and the intake pipe length H3 is set during other fishing or work using medium speed rotation N3. By adjusting the positions of the switching shutter 10 and the pipe length adjustment pipe 12 each season when fishing methods change, the best intake pipe length can be obtained according to each rotation speed. This means that the highest volumetric efficiency can be obtained depending on the engine speed, and an internal combustion engine with a wide range of high output and high torque can be obtained.

In particular, in this invention, the adjustment range by the pipe length adjustment pipe is limited to the medium-speed rotation range, and the shorter branch intake passage is opened for high-speed rotation to obtain the optimum intake pipe length in the high-speed rotation range. Because of this, the range of entry and exit of the pipe length adjustment pipe is limited to a small range in the medium speed rotation range, so the space for the sliding range is small, which has the effect that the intake silencer can be configured as a combination I. There is.

Of course, in this case, the branch part of the high-speed side intake passage must be provided closer to the intake port than the manual range of this pipe length adjustment pipe, and the intake silencer will be larger accordingly than if the branch part is not provided. However, the structure can be more compact than adjusting the length corresponding to this high-speed rotation range using only the length adjusting tube.

Furthermore, the length of the intake pipe was changed by providing an opening in the middle of the intake pipe and switching the intake passage on the inlet side and the opening side of the intake pipe as appropriate using a switching shutter. There is one described in the -14020 publication.

However, if the idea described in this publication is applied to a device equipped with a pipe length adjustment pipe as described above, the intake passage on the high speed side becomes too short, and there is a drawback that it is not necessarily possible to obtain the most suitable intake pipe length for high speed rotation. be.

That is, as mentioned above, the branch part for forming the suction passage in two directions needs to be formed closer to the intake port than the sliding range of the pipe length adjustment pipe, and the opening part of the above-mentioned Japanese Utility Model Publication No. 5014020 is The same is true for is limited to the opening position of
Since it must be provided closer to the intake port than the sliding range of the pipe length adjustment pipe, it generally has the disadvantage of being too short.

On the other hand, in the present invention, the end of the intake pipe on the high-speed side protrudes beyond the other intake pipe as a branch pipe, not just an opening, so there is no such drawback and it is possible to By adjusting the pipe length, it is possible to easily obtain the intake pipe length that is most suitable for the high-speed rotation range.

Furthermore, if an opening is provided in the outer circumferential wall of the intake pipe as described above, the machining to form the opening is troublesome, and furthermore, this opening part has the disadvantage of increasing suction resistance at high speeds. Since the present invention is a branch pipe, it can be easily formed integrally by casting or the like, and it flows smoothly from either branch pipe side, so there is no such drawback.

Furthermore, in the present invention, noise caused by air column vibration can be reduced by arranging the suction side of such an intake pipe in the intake silencer, and especially in the case of a multi-cylinder engine, each intake pipe can be connected to one By arranging it inside the intake silencer, the structure can be simplified for attachment to the engine body, and the structure can be made compact.

Furthermore, since the length adjustment tube of the present invention is used while being fixed at an appropriate position, it is inexpensive, rather practical, and durable, unlike a tube that constantly moves in conjunction with changes in engine speed. You can get something excellent.

[Brief explanation of drawings]

FIG. 1 is a side view of a three-cylinder internal combustion engine showing an embodiment of the present invention, FIG. 2 is an enlarged vertical sectional view of the tip of the intake pipe, and FIG.
The figure is a diagram showing the relationship between volumetric efficiency and engine speed when an intake inertia pipe is used in the embodiment of the present invention. 1... Intake pipe, 6... Intake silencer, 8
...Branch tube, 10...Switching shutter,
11a...Main suction passage, 11b...
Sub-suction passage, 12...pipe length adjustment pipe.

Claims (1)

[Scope of utility model registration request] In an intake pipe of an internal combustion engine, one end of which is connected to an intake port of the engine, the suction side of the intake pipe is placed in an intake silencer, and the intake pipe is branched into a long length within the intake silencer. A medium-speed suction passage and a short high-speed suction passage are formed, and a switching shutter is attached to this branch portion to enable each passage to be opened and closed as appropriate in accordance with the rotational speed of the internal combustion engine. The suction open end of the medium-speed suction passage is provided with a pipe length adjustment pipe that can freely move in and out of the pipe end and can be fixed at an appropriate position in order to change and adjust the length of the suction passage. An intake inertia pipe for an internal combustion engine characterized by: