JPS61157719A - Air intake device of multicylinder engine - Google Patents

Abstract

PURPOSE:To facilitate incorporation of a control valve to communicating passages while securing intake inertia effect by utilizing a portion of a tank to form independent air intake passages leading to cylinder and communicating paths of the passages in an integrated force and forming the portion of the tank in a separated form. CONSTITUTION:Lower stream ends of respective independent air intake passages 6 are opened to combustion chambers 5 of respective cylinders 4 through intake ports 7 and upper stream ends are communicated to a first volume chamber 8a of an air intake expansion chamber 8. Second passages 13 are branched from the way of the passages 6 and the other ends are communicated to a second volume chamber 8b of the expansion chamber 8, and respective second passages 13 are provided with control valves 14 opening and closing the passages 13. In this case, an intake system structure 16 consists of a tank unit 17 forming the chamber 8, integrated intake pipe units 18 and branched intake pipe units 19 respectively forming upper stream side portions 6a and lower stream side portions 6b of the passages 6, and a communicating pipe unit 20 forming the second passages 13 integrally, and it is divided into upper and lower portions at the position of a partitioning board 9.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention connects each cylinder and an intake expansion chamber (tank) through independent intake passages, thereby utilizing the dynamic effect of intake air (intake inertia effect). The present invention relates to an improvement of an intake system for a multi-cylinder engine designed to improve output.

(Prior Art) Conventionally, in an engine intake system, a negative pressure wave (pressure wave of negative pressure) generated with the start of intake is reflected at the open end of the intake passage to the atmosphere or the intake expansion chamber on the upstream side of the intake passage, and a positive pressure wave ( Taking advantage of the fact that the positive pressure wave becomes a positive pressure wave and returns toward the intake port, the positive pressure wave reaches the intake port just before the intake valve closes and forces the intake air into the combustion chamber. It is known to increase the filling efficiency of the intake air by the so-called inertia effect of the intake air. When trying to use such technology, if the shape of the intake passage is constant, the imaging cycle of the pressure waves generated in the intake passage and the opening/closing cycle of the intake valve will match, resulting in an intake inertia effect. is limited to a specific rotation range.

For this reason, conventionally, as seen in Japanese Patent Application Laid-Open No. 115819/1982, the length of the intake passage is changed depending on the engine speed. For example, the intake passage for each cylinder is divided into A long passage and a short passage are formed by branching, and the upstream ends of these passages are opened to an intake expansion chamber, etc., and a control valve is provided in the short passage, and this control valve is opened in a high rotation range. An intake system has been proposed in which the effective length of the intake passage is shortened (see Figure 6 of the above-mentioned publication), thereby reducing the inertia effect of intake air in the low-speed range and the high-speed range, respectively. .

(Problems to be Solved by the Invention) By the way, when an engine and its intake system are mounted in the engine compartment of a passenger car, etc., the rear part is restricted by the front end of the passenger compartment, the upper part is restricted by the bonnet, etc. There is a space constraint that it must be accommodated within a limited space.

Therefore, as in the above proposed example, a second passage is provided that communicates the middle of each independent intake passage that connects the intake expansion chamber (tank) and each cylinder independently with the intake expansion chamber, and the second passage In an intake system for a multi-cylinder engine, which is equipped with a control valve that opens and closes depending on the engine operating condition, in order to eliminate the above-mentioned space constraints, each of the independent intake passages is arranged around the intake expansion chamber. The idea is to make it more compact by integrally forming a part of the constituent wall for use as a handrail, and by integrally forming each of the second passages with a part of the intake expansion chamber. It will be done.

However, in this case, when assembling the lbIIgla valve to the second passage, since the intake expansion chamber, each independent intake passage, and each second passage are integrally formed as described above, it is difficult to assemble the control valve. This is not possible, and it is necessary to provide a dividing surface.

Therefore, the present invention has been made in view of these points, and its object is to provide an intake expansion chamber (in which each independent intake passage and each second passage provided with a control valve are integrally formed).
By providing a dividing surface at an appropriate position relative to the tank), the intake system, which provides an intake inertia effect in the low and high rotation ranges, can be compacted to fit within a limited space. The purpose of assembling the control valve is to ensure good performance.

(Means for solving the problem) In order to achieve the above object, the solving means of the present invention connects at least one space inside the tank and each cylinder through independent intake passages for each cylinder, which are independent from each other. In addition, a second air intake passage communicating with the space inside the tank is provided in the middle of each independent intake passage.
The present invention is directed to an intake system for a multi-cylinder engine in which a passage is provided, and a control valve that opens and closes in accordance with the operating state of the engine is provided in the eight second passages. On the other hand, each of the independent intake passages is integrally formed using a part of the tank-constituting wall that constitutes the space around the tank. Further, each of the second passages is formed integrally with a part of the tank. A part of the tank including each of the second passages and another part of the tank are divided by a dividing plane along the longitudinal direction.

(Function) With the above configuration, in the present invention, when each second passage is closed by the control valve at a low engine rotation speed ta that is less than a set value, negative pressure waves propagating from each cylinder are transmitted to each independent intake passage. As a result, the passage length from the tank to each cylinder is relatively long in order to obtain the intake inertia effect, and this reduces the intake air flow in the low rotation range. Inertial effects are suppressed. On the other hand, in the high rotation range where the number of engine revolutions exceeds the set value, the control valve
When the passage is opened, each cylinder communicates with the space inside the tank via the second passage in the middle of each independent intake passage, and the negative pressure waves propagating from each cylinder via this route are reversed into positive pressure waves and reflected. As a result, the effective length of the intake passage for obtaining the intake inertia effect is shortened, and the intake inertia effect in the high rotation range is enhanced.

In that case, each independent intake passage is integrally formed around the tank using a part of the tank constituent wall, and each second passage is integrally formed in a part of the tank, and there are limited The required intake passage length and required intake expansion chamber volume to obtain the above-mentioned intake inertia effect are ensured while being compact enough to fit within a small space.

Furthermore, since the part of the tank including each of the second passages and the other part of the tank are divided by a dividing plane along the longitudinal direction, each part of the tank in the partially divided part of the tank is It becomes possible to easily assemble the control valve to the two passages from the space side.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIGS. 1 to 3 show a first embodiment in which the present invention is applied to a four-cylinder, four-stroke engine. In the figure, reference numeral 1 denotes an engine body consisting of a cylinder block 2, a syringe head 3, etc., and the engine body 1 has four cylinders 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4. ... are formed in series.

A combustion chamber 5 is formed in each cylinder 4.

Reference numeral 6 denotes independent intake passages provided independently of each other for each cylinder, and each independent intake passage 6 is connected via an intake boat 7 formed in the cylinder head 3 and constituting the downstream end of the independent intake passage 6. It opens into the combustion chamber 5 of each cylinder 4. Reference numeral 8 denotes an intake expansion chamber made of a substantially rectangular cylindrical tank extending parallel to the longitudinal direction of the engine. It is divided into a volume chamber 8a and a second volume chamber 8b having a relatively small volume on the lower side. The upstream ends of each of the independent intake passages 6, 6, . . . are connected to the first volume chamber 8a of the intake expansion chamber 8 with substantially the same passage length. An intake air introduction pipe 1o for introducing outside air is connected to one end surface of the first volume chamber 8a.
A throttle valve 11 for controlling the amount of intake air is disposed inside, and the first volume chamber 8 is connected to the intake air introduction pipe 10.
The intake air introduced into a is passed through each independent intake passage 6 to 8 air 1
It is designed to be supplied to a combustion chamber 5 of 1i4.

Further, the intake boat 7 is provided with an intake valve 12.

Further, a second passage 13 is branched from a midway point of each of the independent intake passages 6, and the other ends of the eight second passages 13, 13, . The intake passages 6, 6, . . . are communicated with each other through the second passage 13 by the second volume chamber 8b.

Further, each of the second passages 13 is provided with a control valve 14 that opens and closes the second passage 13.
4 is integrally and interlockably fixed to a valve shaft 15 extending parallel to the longitudinal direction of the intake expansion chamber 8, and is connected via an actuator by a control circuit that receives an output from an engine rotation speed detection means, etc. (not shown). The opening and closing are controlled by
Each independent intake passage 6, 6, . . . is formed by the second volume chamber 8b.
The communication between them is controlled and operated according to the engine operating status.

It is controlled so that it is closed in a low speed range where the engine speed is less than a set value, and opened in a high speed range where the engine speed is higher than the set value. Note that the opening and closing operation of the control valve 14 according to the engine speed may be performed at least during high loads when output is required, and the control valve 14 may be in the open state or in the open state during low loads. It may be maintained.

In such an intake system, 16 is:
An intake system structure for forming the intake expansion chamber 8, each independent intake passage 6°6, and each second passage 13, 13, and the structure 16 includes the intake expansion chamber 8. Tank section 1 constituting (first volume chamber 8a and second volume chamber 8b)
7 and extends around the tank section 17 from the upper side of the tank section 17 on the side opposite to the engine side to the side and lower sides, and utilizes part of its constituent walls, that is, the side wall and the lower wall. The upstream ends of the upstream portions 5a, 5a... of the independent intake passages 6, 6... are connected to the tank portion 17 (the first
Volume chamber 8a) Integral intake pipe portions 18, 18... integrally formed so as to open at the upper side of the side, and from the lower side of each integrated intake pipe portion 18, 18... toward the engine side. Branch intake pipe portions 19, 19, . . . branch and extend for each cylinder and form downstream portions 6b, 611, . In the vicinity of the branch intake pipe section 19, the tank section 17 (second volume chamber 8b
) that integrally forms a second passage 13 that communicates the middle of each independent intake passage 6 with the second volumetric mass 8b by using the lower wall of the constituent walls of It consists of 7 tank parts 21 that connect the tips of the 10 branch intake pipe parts 19, 19... to each other, and the 7 tank parts 21 have independent intake passages of each branch intake pipe part 19 with respect to the C engine body 1. With the downstream portion 6b aligned with the intake boat 7 of each cylinder 4, it is fixed to the engine body 1 by inserting and tightening bolts 22, 22, . . . from the side. Further, the upper side of the tank 117 on the engine side is formed so as to bulge toward the engine side, thereby ensuring a sufficient volume of the first volume chamber 8a.

Further, the independent intake passage downstream portion 6b of each of the branch intake pipe portions 19 and each intake boat 7 are connected to the combustion chamber 5 from diagonally above.
The combustion chamber 5 is formed to extend substantially linearly toward the combustion chamber 5 and open into the combustion chamber 5. An injection valve mounting hole 23 is formed in the upper part near the downstream end of the downstream side portion 6b of the independent intake passage of each branch intake pipe section 19, and the fuel injection valve 24 has a seal ring 23a at its tip injection port. It is inserted into the mounting hole 23 and fixed therethrough. The installation direction of the mounting hole 23 and the fuel injection valve 24 is such that the fuel from the injection valve 24 is directed to the combustion chamber 5.
Each of the fuel injection valves 24, 24, . . . is connected to a fuel supply pipe 25 arranged parallel to the longitudinal direction of the engine. As a result, the fuel injection valve 24 is connected to the branch intake pipe section 19.
The intake expansion chamber 8 is installed on the extension line of the center line of the fuel injector 24.
(tank part 17) includes fuel injection valve 24 and fuel supply pipe 2
It will be located close to 5.

Further, a control valve 1 is provided in the second passage 13 of each communication pipe section 20.
4 is arranged, and the intake expansion chamber 8 (tank part 1
7) is located on the center extension line p of the fuel injection valve 24, the intake system structure 16 is located at a position below the center extension line intersection in the tank portion 17 and on each second
The length of the intake expansion chamber 8 is at the position of the partition plate 9 between the second volume chamber 8b of the intake expansion chamber 8 including the passages 13, 13, . . . and the first volume chamber 8a of the intake expansion chamber 8. It is formed by being divided into upper and lower parts by a dividing plane along the direction,
Upper half of tank part 17 and each integral plate trachea part 18.18
... an upper divided body 16a whose upper half is integrally molded;
Lower half of tank part 17, integral plate trachea part 18, 18...
, each branch intake pipe section 19, 19..., each communication pipe section 20, 20..., and an upper division body 16b in which seven tank sections 21 are integrally molded, and both division bodies 16a, 1
6b are joined via the partition plate 9, and the bolts 26.2
6... are inserted from below and tightened to form an airtight connection.

Next, to describe the operation of the above embodiment, each control valve 1
4 is closed and the second passage 13 is blocked, thereby causing the second volume chamber 8b to close.
When the communication between each independent intake passage 6.6 is cut off, the negative pressure wave generated during the intake stroke of each cylinder 4 is propagated to the first volume chamber 8a and reflected there. As the negative pressure waves and their reflected waves propagate through a relatively long passage, the oscillation cycle of these pressure waves matches the intake valve opening/closing cycle in the low rotation range, and the inertial effect of intake air in the low rotation range is reduced. is enhanced,
Intake air filling efficiency is improved. On the other hand, when each of the control valves 14 is opened and the second passage 13 is opened, and the independent intake passages 6, 6... are in communication with each other by the second volume chamber 8b, the intake air of each cylinder 4 is The negative pressure wave generated during the stroke causes the second
By shortening the length of the passage that is reflected in the second volume chamber 8b via the passage 13 and provided for the propagation of the negative pressure wave and the reflected wave, the intake inertia effect is enhanced in the rotation range, and the intake inertia effect is increased in this operating range. In this case, the pressure waves propagated from other cylinders also act effectively through the second volume chamber 8b, and the filling efficiency in the rotation range is greatly increased. Therefore, at least when the load is on the side, the control valve 14 is operated on the lower rotation side at a predetermined rotation speed corresponding to the intermediate rotation speed between the low rotation speed range and the rotation speed range where the intake inertia effect is obtained between the low rotation range and the ^ rotation range. By closing the control valve 14 and opening the control valve 14 at higher rotation speeds, the intake air filling efficiency can be increased over the entire rotation range and the output can be improved. In particular, the intake air filling efficiency in the ^ rotation range can be further increased due to the pressure propagation effect between the cylinders, compared to the conventional case where the intake passage was simply shortened to increase the inertia effect. .

The sizes of the first and second volume chambers 3a and 8b that are suitable for effectively exerting the above-mentioned functions are as follows:
It is desirable that the first volume chamber 8a has a capacity of 0.5 times or more the displacement, and the second volume chamber 8b has a capacity of 1.5 times or less of the displacement. Further, it is desirable that the second volume chamber 8b has a smaller capacity than the first volume chamber 8a, and that the cross-sectional area of the second volume chamber 8b is larger than the cross-sectional area of each independent intake passage 6.

In this case, the tank portion 17 that constitutes the intake expansion chamber 8 (the first volume chamber 8a and the second volume chamber 8b) in the intake system structure 16 and the integrated intake that constitutes the upstream portion 6a of each independent intake passage 6 The pipe portion 18, the branch intake pipe portion 19 constituting the downstream portion 6b of each independent intake passage 6, and each second passage 13
Each independent intake passage 6
while detouring around the intake expansion chamber 8 and
(Tank part 17) is integrally formed using a part of the constituent wall, and each second passage 13 is connected to the intake expansion chamber 8.
Since it is formed integrally with a part of the constituent wall of the second volume chamber 8b, the required length of the independent intake passage 6 and each of the first and second volume chambers 8a and 8b of the intake expansion chamber 8 are When the required volume is 1q, these intake systems can be formed compactly and small, so that the above-mentioned required length and required volume can be sufficiently secured within a limited space (a small space). This makes it possible to improve on-vehicle compatibility.

Further, the fuel injection valve 24 is arranged near the downstream end of one of the branched intake pipe sections, that is, on the downstream side of the independent intake passage 6, so that the injected fuel can be atomized well and supplied to the combustion chamber 5 with good response. The tank portion 17 (intake expansion chamber 8) of the intake system structure 16 is located close to the center extension line p of the fuel injection valve 24 because the fuel injection valve 24 is mounted toward the fuel injection valve 24;
It is also necessary to provide a control valve 14 in each of the second passages 13. Therefore, the intake system structure 16 is located at a position below the center extension 1119 in the tank portion 17, that is, on the branch intake pipe portion 19 side, and along the longitudinal direction of the intake expansion chamber 8 at the position of the partition plate 9. Both divided bodies 1 are vertically divided into an upper divided body 16a and a lower divided body 16b at the dividing plane.
6a and 16b are connected via the partition plate 9,
After attaching the lower divided body 16b to the engine body 1 at its seven tank portions 21 by tightening the bolts 22 from the side, the lower divided body 16b is attached to the injection valve mounting hole 23 of each branch intake pipe portion 19 of the lower divided body 16b. Each fuel injection valve 24 is attached by inserting the fuel injection valve 24 from the direction of the center extension line 9 and fixing the fuel supply pipe 25 to the lower divided body 16b.
The control valve 14 is inserted into the second passage 13 of each communication pipe portion 20 of the lower divided body 16b from above and fixed to the valve shaft 15, and then the partition plate 9 is interposed with respect to the lower divided body 16b. By joining the lower divided body 16a and joining the two parts 16a and 16b together by tightening the bolt 26 from below, good formability is ensured and the upper and lower divided bodies 16a and 16b are joined together. Not only can it be easily assembled, but also the control valve 14 and the fuel injection valve 2 can be easily assembled.
4 can be easily assembled, and good assembly can ensure stability.

Moreover, since the connection between the lower divided body 16a and the lower divided body 16b is performed by tightening the bolts 26 from below, the tank portion 17 ( It is possible to form a bulge in the upper part of the side of the intake expansion chamber 8) on the engine side, which has the advantage that a sufficient volume of the intake expansion chamber 8, particularly the first volume chamber 8a, can be secured. Further, the second volume chamber 8b is formed by dividing the tank portion 17 of the intake system structure 16 into upper and lower parts with a partition plate 9.
Since it is provided in the volume chamber 8a and is formed by sharing a part of the constituent wall (partition plate 9) of the first volume chamber 8a, the above-mentioned intake system can be made more compact.

FIG. 4 shows a second embodiment of the present invention. In the first embodiment, the intake expansion chamber 8 is divided into a first volume chamber 8a and a second volume chamber 8b to provide a low rotation range and a high rotation range. In addition to obtaining an intake inertia effect, the intake air filling efficiency is further increased by propagating pressure waves between cylinders in the high rotation range. This is an example of one that increases the intake inertia effect.
Note that the same parts as in the first embodiment (FIGS. 1 to 3) are designated by the same reference numerals, and detailed explanation thereof will be omitted.

That is, in the intake system structure 16, the second passages 13, 13, .
A control valve 14 is provided in the 8th second passage 13 to open and close according to the operating state of the engine. The generated pressure wave is propagated between the intake expansion chamber 8 and the intake passage 6, which is relatively long, and as a result, the oscillation period of this pressure wave and the intake valve opening/closing period are matched to improve intake air in the low rotation range. Increase inertia effect. On the other hand, in the high rotation range, control valve 1
4, the middle part of each independent intake passage 6 is communicated with the intake expansion chamber 8 via the second passage 13, and the propagation path of the pressure wave is made relatively short, thereby reducing the vibration of the pressure wave in the high rotation range. The period and the intake valve opening/closing period are matched to enhance the intake inertia effect.

In this case as well, as shown in the figure, each independent intake passage 6, 6, etc. is integrally formed around the tank part 17 by the intake system Ha construction body 6, using a part of the wall constituting the tank part 17. In addition, each second passage 1 is formed in a part of the tank part 17.
3.13... are formed in one direction, and the intake system structure 16 is located below the intersection of the center extension lines of the fuel injection valves 24 in the tank portion 17 (intake expansion chamber 8). The lower part of the intake expansion chamber 8 including the L-signed second passage 13, 13... and the upper part of the intake expansion chamber 8 are divided into upper and lower parts along the longitudinal direction thereof, 1st above
As in the case of the embodiment, it is possible to achieve both the in-vehicle mountability of the intake system for obtaining the intake inertia effect and the improvement in assembly.

In addition to the embodiments described above, the present invention provides an upper and lower first volume chamber 8a and a second volume chamber 8b in the partition plate 9 in the first embodiment.
It is also applied to an intake system in which a communication hole is provided to communicate with the engine, and the intake pressure vibration between the upper and lower volume chambers 88.8b of the low rotation range C is used to further increase the intake air filling efficiency. It is possible.

Further, the present invention is not limited to a four-cylinder engine as in the above embodiments, but can be applied to other multi-cylinder engines, such as a 5-cylinder engine. Of course, the present invention can also be applied to an L engine or a 6-cylinder engine.

(Effects of the Invention) As explained above, according to the present invention, the independent intake passages leading to each cylinder are integrally formed around the tank by using a part of the wall that constitutes the tank, and each independent intake passage A second passage that communicates with the space inside the tank and has a control valve is formed integrally with a part of the tank, so that the intake inertia can be controlled in the low rotation range and the high rotation range, respectively, within a limited space. While ensuring the necessary intake passage length and intake expansion chamber volume to obtain the effect, the part of the tank containing each of the second passages is separated from the other tank parts by a dividing plane along the longitudinal direction. Since it is formed in parts, the control valve can be easily attached to the second passage, and its assembly can be ensured, regardless of the compact and integral structure of the intake system. Therefore, it is possible to achieve both improvement in vehicle mountability of the intake system that exhibits the intake inertia effect and improvement in ease of assembly.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the invention, and FIGS.
1 is a longitudinal sectional side view taken along line II in FIG. 3, FIG. 2 is a longitudinal sectional side view taken along line ■-■ in FIG. 3, and FIG. be. FIG. 4 is a diagram corresponding to FIG. 1 showing the second embodiment. DESCRIPTION OF SYMBOLS 1... Engine body, 4... Cylinder, 6... Independent intake passage, 8... Intake expansion chamber, 8a... First volume chamber,
8b...Second volume chamber, 13...Second passage, 14...
・ili'l Morning valve, 16... Intake system structure, 16a
...Upper divided body, 16b...Lower divided body, 17...
-Tank part, 18...Integrated intake pipe part, 19...Branch intake pipe part, 2o...Communication pipe part.

Claims (1)

[Claims] (1) At least one space inside the tank and each cylinder are connected by independent intake passages for each cylinder, and a second passage is provided in the middle of each independent intake passage to communicate with the space inside the tank. In an intake system for a multi-cylinder engine in which each of the second passages is provided with a control valve that opens and closes depending on the operating state of the engine, each of the independent intake passages is connected to a tank-constituting wall that constitutes the space around the tank. Each of the second passages is formed integrally with a part of the tank, and the part of the tank including the second passage and the other part of the tank are integrally formed using a part of the tank. An intake system for a multi-cylinder engine, characterized in that the parts are divided by dividing planes along the longitudinal direction of the parts.