JPH0341057Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an engine intake system, and particularly to an engine intake system that utilizes a resonance effect to improve charging efficiency.

[Prior Art] Conventionally, an intake system has been provided with two groups of intake system collecting parts in which cylinders having non-consecutive firing orders are collected, and a resonant intake passage formed upstream of the collecting part, and a partition wall that partitions the upstream resonant intake passage. A hole is opened in the middle, and a valve is installed to open and close this hole.The upstream side resonance intake is closed at low engine speeds and opened at high engine speeds to obtain a resonance effect that corresponds to the engine speed. An engine intake device in which the communication length of a passage is changed has been proposed (Japanese Patent Application Laid-open No. 148025/1983).

However, in the above-mentioned conventional engine intake system, the communication length of the upstream resonance intake passage is only switched in two stages depending on the high or low engine speed, so an effective resonance effect can be obtained at medium speeds. Therefore, there was a problem in that it was not possible to effectively respond to engine operating conditions where the speed changes over a very wide range from low to high speed.

Of course, if multiple holes are provided in the partition wall and an on-off valve is provided for each hole, the communication length can be switched in multiple stages, but this would require a large number of on-off valves, making control complicated. , there is a problem of high cost.

[Purpose of the invention] The purpose of the invention is to obtain good output performance over a wide operating range of the engine by controlling the natural frequency of the intake system in at least three steps using a single on-off valve. be.

[Structure of the invention] For this reason, the main body is equipped with a surge tank that is internally divided into two surge tank chambers with a partition wall in between, and each surge tank chamber contains each of the cylinder groups whose ignition order is not consecutive. In an engine intake system in which intake passages communicate with each other and resonant intake passages communicate with the upstream side of each surge tank chamber, the partition wall of the surge tank extends from the upstream side of the surge tank chamber to the downstream side of the surge tank chamber. An opening that communicates both the surge tank chambers with each other in the middle, and a wall that projects into the surge tank chambers from one side of the opening on the upstream side of the surge tank chamber,
The opening consists of a wide valve body having a width approximately equal to the width of the opening, and a narrow valve body having a width approximately 1/2 of the width of the opening and fixed at right angles to the wide valve body, The wide valve body is rotatably supported substantially at the center in the width direction of the opening of the engine, and the wide valve body is in a position substantially perpendicular to the wall in the low speed rotation range of the engine, and in a position opposite to the wall in the medium speed rotation range of the engine, By providing an on-off valve with a T-shaped cross section that is at a position intermediate between the above two positions in the high-speed rotation range of the engine, the state of communication between both surge tank chambers of the surge tank is changed in multiple stages.

[Effects of the invention] According to the main body, the communication state between the two chambers of the surge tank can be switched in multiple stages, so the natural frequency of the system can be set in multiple stages, and the resonance effect can be maintained over a wide operating range. can be obtained, and the output performance of the engine can be improved.

[Example] Hereinafter, an example of the main body will be described with reference to the attached drawings.

As shown in Fig. 1, the surge tank is formed into a relatively flat box shape, and is divided into two surge tank chambers 3 and 4 by a partition wall 2 provided along the longitudinal center line. It is divided into two equal parts. The two surge tank chambers 3 and 4 contain a group of cylinders whose ignition order is not consecutive (for example, in the case of a V-type 6-cylinder engine, a group of cylinders #1, #3, and #5, and a group of cylinders #2, #4,
#6 cylinder group) each intake passage 5, 5, ...; 6,
6, .

As shown in FIGS. 1 and 2, a communication opening 9 is formed in the partition wall 2 that partitions the two surge tank chambers 3 and 4, and the communication opening 9 communicates the two chambers.
An orthogonal wall 10 is formed on one edge of the opening, and extends by a predetermined width W/2 in the left and right directions perpendicular to the partition wall 2, where W is the opening width of the communication opening 9.

Further, the communication opening 9 is provided with an on-off valve 11 that opens and closes it. This on-off valve 11 has a wide valve body 11a having a width equal to the width W of the orthogonal wall 10, in other words, the opening width W of the communication opening 9, and when this wide valve body 11a is viewed as the upper side of the T-shape, It consists of a valve body with a T-shaped cross section formed by a narrow valve body 11b with a width W/2 corresponding to the legs of the T-shape, and a wide valve body 11a and a narrow valve body The meeting portion with the valve body 11b is rotatably supported.

The upper end of the shaft 12 is projected upward from the upper surface of the surge tank 1 and is connected to an operating rod 15 of an actuator 14 via a lever 13. This actuator 14 is operated by, for example, an intake negative pressure fixed on the surge tank 1.
It is formed of a diaphragm device with a heavy diaphragm structure, and is configured to provide a total of three stages of operation depending on the operating state of the engine, specifically, the engine speed.

Although the structure of the diaphragm device constituting this actuator 14 is not specifically shown, it can be a well-known structure in which diaphragms forming two pressure chambers are linked with each other with a predetermined play. By applying atmospheric pressure or negative intake pressure to the two pressure chambers formed, the on-off valve is switched to three positions shown in FIG.

In the position shown in FIG. 3, the wide valve body 11a is opposed to the orthogonal wall 10, and a communication passage 16 of length W is formed between the two, and the communication passage 16 connects both the surge tank chambers 3 and 4. communicate.

In the position shown in FIG. 3, the wide valve body 11a of the on-off valve 11 is perpendicular to the orthogonal wall 10, completely closing the communication opening 9 and cutting off communication between the surge tank chambers 3 and 4.

Further, in the position shown in FIG. 3, the wide valve body 11a is opened at an angle of about 45 degrees with respect to the communication opening 9, so that both the surge tank chambers 3 and 4 are in direct communication with each other.

FIG. 4 shows the on-off valve 11, FIG.
This shows the torque characteristics of the output shaft obtained when the engine was operated with the engine held at each position shown in FIG.

It should be noted that the three types of torque characteristic curves shown in FIG. 4 are given the reference numerals corresponding to the respective positions in FIG. 3.

As shown in Fig. 4, in the low engine speed region where the engine speed is lower than Ra, the torque characteristic curve at the position, that is, when the communication opening 9 is fully closed, shows the largest value, and when the engine speed is higher than or equal to Ra, the torque characteristic curve shows the largest value. In the medium-speed operating range, the communication state shown in FIG.
The torque characteristic curve obtained when the two are in communication shows a large value.

Furthermore, in the high-speed operation range where the engine speed is Rb or higher, the position of both surge tank chambers 3,
The torque characteristic curve in a state in which 4 is in direct communication exceeds the torque characteristic curve and shows a high peak.

Therefore, the low engine speed range (Ra
lower), and Rb in the medium speed range (Ra or higher).
lower) position, and higher speed range (Rb or higher)
If the actuator 14 is used to switch the on-off valve 11 so as to change the position, a high engine output can be obtained in any operating range.

That is, by switching the position of the on-off valve 11 as described above, the natural frequency of the resonance intake system is changed according to the operating state of the engine, and an effective resonance effect can be obtained in any operating state.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the main parts of an engine intake system according to an embodiment of the present invention, Fig. 2 is a sectional view taken in the - line direction of Fig. 1, and Fig. 3, , are explanations showing the operating positions of the on-off valves, respectively. 4 are graphs showing torque characteristic curves obtained when the on-off valve is held at each position. 1... Surge tank, 2... Partition wall, 3, 4...
...Surge tank chamber, 5, 6...Intake passage leading to each cylinder, 7, 8...Resonant intake passage, 9...Communication opening, 10...Orthogonal wall, 11...Opening/closing valve, 14...
Actuator.

Claims (1)

[Scope of Claim for Utility Model Registration] A surge tank is equipped with a surge tank that is internally divided into two surge tank chambers with a partition wall in between, and each surge tank chamber has intake passages for cylinder groups whose ignition order is not consecutive. In an engine intake system in which a resonant intake passage is connected to the upstream side of each surge tank chamber, the partition wall of the surge tank is connected to both sides on the way from the upstream side to the downstream side of the surge tank chamber. The opening includes an opening that communicates the surge tank chambers with each other, and a wall that projects into both the surge tank chambers from one side of the opening on the upstream side of the surge tank chamber, and the opening has a wide width that is approximately equal to the width of the opening. Consisting of a valve body and a narrow valve body having a width approximately 1/2 of the opening width and fixed at right angles to the wide valve body, the valve body is rotatably supported approximately at the center of the opening in the opening width direction. The wide valve body is at a position almost perpendicular to the wall in the low speed rotation range of the engine, is in a position opposite to the wall in the medium speed rotation range of the engine, and is in a position between the above two positions in the high speed rotation range of the engine. An intake system for an engine, characterized by comprising an on-off valve having a T-shaped cross section.