JPS61255213A - Intake control device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To perform smooth operation and provide high filling efficiency, according to the method wherein an intake control valve is constituted as a rotary valve which is rotated around an axis extended perpendicularly to the axis of an intake passage, and a valve opening, shutting off intake air for a given time after opening of an intake valve, is provided. CONSTITUTION:An intake control valve 21, disposed in an intake manifold 3, is formed as a rotary valve formed in a cylindrical shape and the like. A cylinder body 23 is engaged internally of a holding part 3a of an intake manifold 3 so that it is rotatable around an axis X-X extended perpendicularly to an axis Y-Y of the intake passage of the intake manifold 3, i.e., the flowing direction of intake air and slidable in a direction X-X. The cylinder body 23 is formed with a first part 25A for middle and low rotation and a second part 25B for high rotation. The first part 25A is formed with an opening part (valve opening) 27, formed by notching a part of the cylinder, and a surface part 29, and the second part 25B is formed with an opening part 33 and a surface part 31.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an intake control device for an internal combustion engine.

[Conventional technology]

By changing the equivalent pipe length of the engine intake passage according to the engine speed, high filling efficiency is ensured not only when the engine is running at high speeds but also when the engine is running at medium to low speeds when the engine is running at full load or under high load. Internal combustion engines are well known (
For example, see Japanese Utility Model Application Publication No. 59-58736).

However, when trying to increase the filling efficiency by changing the equivalent pipe length of the intake passage in this way, the width of the engine speed is actually about 1000 r, p, m which is preset when the engine rotates at low and medium speeds. There is a problem in that the charging efficiency can only be increased in the middle range of 1, and it is no longer possible to increase the charging efficiency if the engine speed is out of this range. In addition, in order to increase the filling efficiency at low engine speeds, the length of the intake passage must be made considerably longer, but in reality it is difficult to make the intake passage longer, so the equivalent pipe length of the intake passage is There is a problem in that it is difficult to increase the charging efficiency when the engine rotates at low speeds by changing the speed.

Therefore, the applicant of the present application previously proposed in Japanese Patent Application No. 18501/1983 to solve the above-mentioned problems from an approach completely different from that of determining the equivalent pipe length of the intake passage. That is, according to this prior application, an intake control valve is provided in the intake passage that shuts off intake air for a predetermined period of time even when the intake stroke is started;
By opening this intake control valve in the latter half of the intake stroke, intake air is sucked into the combustion chamber at once by utilizing the large intake negative pressure generated when the intake control valve is closed, thereby improving intake air filling efficiency. The aim is to increase shaft output torque, especially in medium and low speed operating ranges.

The present invention relates to such a novel concept, that is, an intake control device in which an intake control valve that opens in the latter half of the intake stroke is provided in the intake passage, and is an extension of two series of prior patent applications. It is.

[Problem that the invention seeks to solve]

However, in the intake control device as described above, since the intake control valve is formed as a butterfly valve, the following problems were found when put into practical use. That is, even if the intake stroke is started when the intake valve is opened, intake air is blocked while the intake control valve is closed, and as a result, a large intake negative pressure is generated downstream of the intake control valve. After the intake control valve opens, this intake negative pressure is actively used to increase the intake efficiency of the intake air. When this happens, the generated negative intake pressure acts on the entire valve plate (valve body) of the butterfly valve, so a large amount of force is required to open and close the butterfly valve, and the butterfly valve opens and closes in a short period of time. Because this is repeated intermittently, if there is a large pressure difference between the two downstream sides of the butterfly valve, the butterfly valve cannot open and close smoothly. As described above, the operational reliability of the intake control valve cannot be said to be fully satisfactory.

In view of the above-mentioned points, an object of the present invention is to configure the intake control valve with a rotary valve that rotates continuously instead of a butterfly valve that repeats opening and closing intermittently, thereby smoothing the operation of the intake control valve with a small driving force. The purpose of the present invention is to improve the operational reliability of the intake control valve.

[Means for solving problems]

In order to achieve the above object, according to the present invention, the intake control valve is configured as a rotary valve that is rotated by an engine (for example, a crankshaft) about an axis substantially perpendicular to the axis of the intake passage. The valve has a valve opening that blocks intake air for a predetermined period of time after the intake valve is opened during the intake stroke, depending on the rotational angular position of the valve.

〔Example〕

Preferred embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is an intake pipe, 3 is an intake manifold downstream thereof, 5 is a cylinder head, 7 is a cylinder block,
9 is a combustion chamber, 11 is a piston that reciprocates within the cylinder block 7, 13 is an intake valve, 15 is an engine body, and 17 is an intake boat.

The intake control valve 21 is arranged within the intake manifold 3. In the illustrated embodiment, the intake control valve 21 is formed as a cylindrical rotary valve, but its shape is not limited to a cylinder, and may be any rotating body such as a truncated cone, a sphere, or the like. The cylindrical body 23 of the intake control valve 21 is centered on the axis y-y of the intake passage of the intake manifold 3, that is, the axis X-X (Fig. 2) extending in a direction substantially perpendicular to the flow direction of intake air (white arrow). It is fitted snugly into the holding portion 3a of the intake manifold 3 so as to be rotatable and slidable in the X-x direction. Since the illustrated embodiment shows the case of a four-cylinder engine, the cylindrical body 2 of the intake control valve 21
3 extends in the axis vAx-x direction across four intake boats 17 as shown in FIG. 2, but basically corresponds to one intake boat 17 and has a configuration as shown in FIG.

In FIG. 3, the cylindrical body 23 of the intake control valve 21 is preferably composed of a first portion 25A for medium and low rotations (for example, 200 rpm or less) and a second portion 25B for high rotations (for example, 2000 rpm or more). be done.

The first part 25A is composed of an opening (valve opening) 27 which is a cutout of a part of a cylinder and a surface part 29. On the other hand, the second part 25
B is the opening 33 and the surface portion 31 that is left from the viewpoint of strength.
It consists of The first portion 25A and the second portion 25B are connected to the intake boat 1 by sliding the intake control valve 21 in the axis X-X direction by an actuator 51, which will be described later.
It can be selectively located within 7. 1st part 2
5A is in the closed position when the surface portion 29 extends into the intake passage as shown in FIG. 1, and is in the open position when the opening 27 is located within 1 m of the intake passage. The intake control valve 21 can alternately occupy a closed position and an open position by rotating the cylindrical body 23 (in the direction of the arrow in FIG. 1). Further, the second portion 25B is preferably provided to prevent the intake control valve 21 from creating intake resistance at high rotational speeds, so that it does not block the intake passage at any rotation angle position of the cylindrical body 21. (FIG. 4) The size of the surface portion 31 is preferably reduced to the minimum size necessary to maintain the strength of the cylindrical body 21. The first
Units consisting of the portion 25A and the second portion 25B are integrally arranged in parallel in the axis XX direction in the same number as the intake boats 17, and constitute an intake control valve. The intake control valve 21 can be made, for example, as a molded product of resin or the like.

The intake control valve 21 is driven to rotate synchronously by the engine. For this purpose, one end of the cylindrical body 23 of the intake control valve 21 is connected to a rotating shaft 43 of a timing gear 41 that is connected to a crankshaft (not shown). The rotating shaft 43 is an insert 4 inserted and fixed into the holding part 3a of the intake manifold.
5, it is rotatably supported via a metal sleeve 47 and an oil seal 49. The outer end of the rotating shaft 43 is formed, for example, as a large-diameter square head 44, and is fitted into a corresponding square groove 26 formed at a corresponding end of the cylindrical body 23 of the intake control valve 21 in a relatively non-rotatable and relatively slidable manner. I am forced to do it. As a result, the rotation of the crankshaft is reliably transmitted to the intake control valve 21 via the timing gear 41 in a one-to-one relationship.

The actuator 51 for sliding the intake control valve 21 in the direction of the axis XX is constituted by a diaphragm device having a negative pressure working chamber 55 formed by a diaphragm 53, for example. The diaphragm 53 is always biased to the left in FIG. 2 by the spring 57. The housing 59 of the diaphragm device 51 is fixed to the wall of the intake manifold 3 by means of bolts 61, for example. An atmospheric chamber 63 is formed on the other side of the diaphragm 53 and is opened to the atmosphere via a boat 67. The diaphragm 53 has an intake control valve 2]
An actuating rod 69 is fixed to the other end (right end) of the cylindrical body 23. The actuating rod 69 slidably passes through a central hole 71 formed in the housing 59 of the diaphragm device via an oil seal 73. The vacuum working chamber 55 is connected by a vacuum conduit 77 having a check valve 75 to a source of intake vacuum (not shown), such as an intake manifold.

A normally closed electromagnetic negative pressure switching valve 81 is provided in the negative pressure conduit 77, and its valve element 83 opens and closes a valve port 84 in response to a signal from a control unit (CPU) 85. For example, an engine speed signal S is input to the CPU 85, and the negative pressure switching valve 81 is turned on only when the engine speed is below a predetermined value and at low speeds.
When the valve is turned to N, the valve is opened and negative pressure is introduced into the negative pressure working chamber 55 of the diaphragm device, and the entire intake control valve 21 is shifted to the right in FIG. 2 by the working rod 69. That is, the first portion 25A of the intake control valve is brought into a first position (FIGS. 1 and 2) located within the intake boat 17. When the rotation speed reaches a predetermined value or higher, the CPU 85 turns off the negative pressure switching valve 81 and closes the valve port 84. As a result, the diaphragm device 5
The diaphragm 53 of No. 1 is returned to its initial position by the spring 57, and the second portion 25B of the intake control valve 21 comes to a second position (FIG. 4) in which the second portion 25B of the intake control valve 21 is located within the intake boat 17. In addition, the negative pressure working chamber 55 of the diaphragm device 51 may be connected to a positive pressure source such as a pressurizing pump, contrary to the above embodiment, and in that case, the operation of the diaphragm device will be reversed to that in the above case. .

As mentioned above, the second portion 25B is intended to prevent the intake control valve from creating intake resistance when the rotation speed is high, so the purpose of the second portion 25B is to increase the filling efficiency during medium and low rotation speeds and to improve the shaft output torque. is not necessarily necessary. That is, in achieving the object of the present invention, the intake control valve has only the first portion 25.
In this case, there is no need to switch the intake control valve between medium, low rotation, and high rotation, so the actuator 51 is also unnecessary.

Opening 27 and surface 2 of first portion 25A of intake control valve 21
The size and positional relationship with 9 are determined as follows.

That is, even when the intake valve 13 opens and the intake stroke starts, the intake control valve 21 (first portion 25A thereof) remains in the open/closed valve state for a while. In other words, the surface portion 2 of the first portion 25A
9 still completely blocks the inlet of the intake boat 17 at the start of the intake stroke (FIG. 1). As mentioned above, the intake control valve 21 is rotated in synchronization with the crankshaft by the timing gear 41, so if the state shown in FIG. The intake control valve remains closed until it reaches the inlet edge 18 of the boat 17. At this time, a large negative pressure is generated downstream of the intake control valve 21, so the surface portion 2
As soon as the end 29a of the intake boat 9 reaches the inlet edge 18 of the intake boat and the intake control valve 21 opens, the intake air is suddenly sucked into the cylinder at once until the intake valve 13 is fully closed (intake stroke). (until the end), the intake air is overfilled and the torque can be greatly increased.

The intake control valve 21 only needs to be fully closed before the start of the next intake stroke, so the valve closing timing may be designed in any manner as long as it is before the intake stroke.

Note that the opening time jjJl of the intake control valve is set at least at the optimal timing from the start to the end of the intake stroke, but for example, the crank angle is set to about 140 degrees after the intake top dead center. .

[Effects of the Invention] By adopting a new intake air inflow method in which the inflow of intake air is blocked even when the intake valve is opened, and then the inflow of intake air is started before the intake valve closes, engine low pressure can be reduced. During medium speed operation, high filling efficiency can be obtained throughout low and medium speed operation. Furthermore, by employing a rotary valve that is rotationally driven by the engine as the intake control valve, the operation of the intake control valve can be made simple and reliable.

[Brief explanation of drawings]

FIG. 1 shows an intake system of an internal combustion engine equipped with an intake control device according to the present invention, and is a sectional view taken along the line 1-1 in FIG. 2, and FIG. 2 is an enlarged partial sectional view of the intake control device according to the present invention. , FIG. 3 is a perspective view showing a part of the intake control valve, and FIG. 4 is a diagram showing the second position of the intake control valve at the time of high rotation. 3...Intake manifold, 13...Intake valve, 21
...Intake control valve, 23...Cylindrical body, 27.
...Opening part, 29... Surface part.

Claims (1)

[Claims] In an internal combustion engine that is provided with an intake control valve that opens in the middle of the intake stroke in the engine intake passage, the intake control valve is configured as a rotary valve that is rotated by the engine about an axis that is substantially perpendicular to the axis of the intake passage. An intake control device for an internal combustion engine, wherein the rotary valve has a valve opening that shuts off intake air for a predetermined period of time after the intake valve opens during an intake stroke, depending on the rotational angular position of the rotary valve.