JPH01314A - engine intake system - 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 (Industrial Field of Application) The present invention relates to an intake device that supplies intake air to each cylinder of a multi-cylinder engine, and in particular, the present invention relates to an intake device that supplies intake air to each cylinder of a multi-cylinder engine, and in particular, uses an annular intake passage to cause a resonance phenomenon of intake air to reduce intake air overflow. Concerning what is provided for.

(Prior Art) Various types of engines have been known in which the charging efficiency of the intake air taken into the cylinder combustion chamber of the engine is increased by the dynamic effect of the intake air, thereby increasing the output torque of the engine. As an example, in Japanese Patent Publication No. 60-14169, the intake passages in a multi-cylinder engine are connected to groups of cylinders in which cylinders with discontinuous intake orders (ignition orders) are grouped into the same group. It is divided into two intake passages, and each intake passage is composed of an enlarged chamber to which the upstream end of the branch part of the intake manifold is connected, and a resonant intake passage connected to this enlarged chamber. The upstream end communicates with the upstream gathering chamber, and the enlarged chamber is provided with a switching device that switches both intake passages into a communication state or a communication cutoff state, and when the communication between the intake passages is cut off by the switching device, each The negative pressure wave generated during the intake stroke of the cylinder is reflected in the upstream collecting chamber and reversed into a positive pressure wave, and the inverted positive pressure wave produces a resonance supercharging effect on the intake air in a relatively low rotation range. On the other hand, when the intake passages are communicated with each other, the inverted reflection position of the intake pressure wave is brought closer to the intake port to increase the natural frequency of the intake pressure vibration and obtain a resonant supercharging effect in the high-speed rotation range. It is done like this.

Furthermore, in the method disclosed in Japanese Patent Application Laid-Open No. 56-52522, a loop is formed in the intake manifold connected to the air cleaner so that intake air flows in one direction within the loop, and a branch is formed in the intake manifold. The connected intake pipe is attached to the manifold so as to form an acute angle with the intake flow direction in the loop, so that the intake air filling efficiency is increased by the inertia force by utilizing the intake air flow velocity in the loop. There is.

(Problem to be Solved by the Invention) By the way, in the former technique described above, a large-volume expansion chamber is provided at the gathering part of the intake manifold branches, so the intake system becomes large and requires a large installation space. There are some problems such as needing to be used.

~ Therefore, in the latter technique mentioned above, we focused on forming a loop part in the intake manifold, and connected each intake port of two cylinder groups in which cylinders with non-consecutive intake orders are grouped into a common group without an enlarged chamber. Connected to the resonance annular intake passage, the resonance annular intake passage extends in two directions, with a portion communicating with each intake port of one cylinder group and a portion communicating with each intake port of the other cylinder group. By forming the cylinder into an annular shape interconnected on both sides, and by forming the length of the communication path on both sides between the two cylinder groups to be sufficiently larger than the length between the intake ports of adjacent cylinders of the same cylinder group,
A positive pressure wave generated in the vicinity of the intake port at the end of the intake stroke of each cylinder is made to substantially circulate around the resonance annular intake passage, and is made to act on the intake ports of other cylinders in the same cylinder group,
It is conceivable to make the size more compact by eliminating the need for an expansion chamber for the intake air while effectively exerting the dynamic effect of the intake air.

Furthermore, in addition to the resonance supercharging effect of intake air created by such an annular intake passage, it is also possible to connect the intake port of each cylinder to an intake passage without a volume expansion chamber such as a surge tank, and increase the resonance frequency of intake air in that intake passage. It is also possible to supercharge the intake air by its resonance effect by setting the length of the intake passage so that the engine speed falls within a specific engine speed range (for example, a low speed range).

However, in the latter case, in reality, it is difficult to achieve the resonant supercharging effect of the intake air through the intake passage well over the entire engine speed range, and although it is sufficient in the high speed engine speed range, It is difficult in this region. That is,
In order for the intake passage to exhibit a good resonant supercharging effect in the low speed range of the engine, it is necessary to increase the overall length of the intake passage. Placing this would go against the original aim of making the intake system more compact.

An object of the present invention is to perform resonance supercharging in the low speed rotation range of the engine with respect to an engine intake system that performs resonance supercharging of intake air through an intake passage without a volume expansion part such as a surge tank as described above. In some cases, by effectively utilizing the annular intake passage structure described above to form a long intake passage, the long intake passage required for resonance supercharging in the low speed range of the engine can be made compact. The goal is to make it possible to form a structure with a unique structure.

(Means for solving the problem) In order to achieve this object, the solution of the present invention transforms the annular intake passage into one intake passage with a long overall length by partially closing it at a predetermined part thereof, In the low rotation range of the engine, this one intake passage is used to obtain a resonance supercharging effect of the intake air. In this case, since there is no annular intake passage, the intake air is resonantly supercharged by the annular intake passage.

In other words, instead of resonant supercharging in which the positive pressure waves generated during the intake stroke of each cylinder circulate around the annular intake passage and act on other cylinders, the negative pressure waves generated in each cylinder are reflected and reversed into positive pressure waves. This causes resonance supercharging to be applied to other cylinders.

Specifically, as described above, the present invention has a resonant annular intake passage to which the intake ports of each cylinder are connected and has no volume expansion part, so that resonance supercharging of intake air is caused by the annular intake passage. This assumes that the intake system of the engine is as follows.

The annular intake passage is connected to a common intake passage connected to the intake port of each cylinder via an independent intake passage, one end of which is connected to the upstream end of the common intake passage, and the other end of which is connected to the downstream end of the common intake passage. Consists of a connected return intake passage.

Furthermore, closing the common intake passage upstream of the connection part with the independent intake passage communicating with the intake port of each cylinder and downstream of the connection part with the upstream end of the return intake passage,
A canceling means for canceling resonance supercharging by the annular intake passage, and a control means for controlling the canceling means to operate in a low rotational speed range of the engine are provided.

(Function) With this configuration, the release means does not operate in the high speed rotation range of the engine, and the resonance annular intake passage does not close. For this reason, there is resonance supercharging, in which the positive pressure waves generated in each cylinder circulate around the annular intake passage and act on other cylinders, or resonance, in which the pressure waves reflected and inverted at the upstream end of the intake passage act on other cylinders. Supercharging occurs, and the output torque of the engine can be increased by this resonant supercharging.

On the other hand, in the low speed rotation range of the engine, the release means is operated under the control of the control means so that the annular intake passage has a predetermined portion, that is, the connection portion with the independent intake passage connected to the intake port of each cylinder. The common intake passage on the upstream side and downstream of the connection part with the upstream end of the return intake passage is closed,
As a result, the resonance supercharging state caused by the annular intake passage is released. As the annular intake passage closes, the annular intake passage becomes one long intake passage, and the negative pressure waves generated in each cylinder are propagated upstream of the intake passage and reflected at the upstream end. After the pressure wave reverses to a positive pressure wave, it returns to the downstream side and changes to a resonant supercharging state that acts on other cylinders, and this resonant supercharging can increase the output torque of the engine.

Therefore, by only partially closing the annular intake passage in this way, a long intake passage for resonance supercharging in the low speed range of the engine is obtained; This means that it can be formed with a compact structure near the engine.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows the overall configuration of a first embodiment of the present invention, in which reference numeral 1 denotes an in-line four-cylinder engine having four cylinders 2a to 2d arranged in series, each of the cylinders 2a to 2d. ~2
d includes an intake port 3 and an exhaust port (not shown). Reference numeral 4 denotes an intake passage that supplies intake air into each of the cylinders 2a to 2d, and this intake passage 4 is connected to a resonance intake passage 5 formed in an intake pipe 8 and a downstream end of the resonance intake passage 5. , an annular intake passage 6 formed by a collecting pipe part 9a of the intake manifold 9, and an independent intake passage 7 formed in each independent pipe part 9b of the intake manifold 9 and branched and connected to the annular intake passage 6. The upstream end of the resonant intake passage 5 is connected to an air cleaner 10. An air flow meter 11 for measuring the amount of intake air is disposed in the intake passage 4 downstream of the air cleaner 10, and a portion of the intake passage 4 downstream of the air flow meter 11 is communicated with a resonance tank 12 having a relatively large capacity. A throttle valve 13 is disposed in the intake passage 4 on the downstream side of the tank 12.

The annular intake passage 6 is formed into an annular shape by bending the annular collecting pipe portion 9a of the intake manifold 9 into two on the downstream side and connecting the bent ends to each other at the upstream portion. Due to this bending structure, the annular intake passage 6 is connected to the intake port 3 of each cylinder 2a to 2d.
a common intake passage 6a connected to the above through the independent intake passage 7, and a return intake passage 6b connected at one end to the upstream end of the common intake passage 6a and at the other end to the downstream end of the common intake passage 6a. It is made up of.

Furthermore, in the common intake passage 6a of the annular intake passage 6, it is located upstream of the connection part with the independent intake passage 7 communicating with each of the cylinders 2a to 2d and downstream of the connection part with the upstream end of the return intake passage 6b. Actuator 1 is installed on the side part.
A first control valve 14 is provided which is a butterfly valve that opens and closes the common intake passage 6b when the common intake passage 6b is driven. Further, a second control valve 15 made of a butterfly valve is disposed at the upstream end of the return intake passage 6b, which opens and closes the return intake passage 6b by driving the actuator 15a. By controlling the opening and closing of these two control valves 14.15, the resonance supercharging state of the intake air and its resonance frequency are changed, and when both control valves 14.15 are opened, the annular intake passage 6 is By connecting each cylinder 2a to 2d in an annular manner without closing it, each cylinder 2a to 2d
An intake resonance supercharging state in which the positive pressure wave generated during the intake stroke circulates around the annular intake passage 6 and then acts on the other cylinders 2a to 2d, or the resonance tank 12 upstream of the intake passage 4 changes from negative to positive. The pressure wave reflected and inverted is transmitted to the other cylinder 2a.
Maintain a resonant supercharging state that acts on ~2d. Further, when the first control valve 14 is closed and the second control valve 15 is opened, the first control valve 1 of the annular intake passage 6
The annular intake passage 6 is closed by closing the common intake passage 6a that is upstream of the connection part with the respective independent intake passages 7 and downstream of the connection part at the upstream end of the return intake passage 6b. The resonance supercharging state caused by Resonant supercharging of the intake air is caused to propagate to the cylinders 5, reversed to a positive pressure wave by reflection at the resonance tank 12 on the way, and return the positive pressure wave to the downstream side to act on the other cylinders 2a to 2d. When the first control valve 14 is opened and the second control valve 15 is closed, the second control valve 1 of the annular intake passage 6 is opened in the same manner as above.
5, that is, the upstream end portion of the return intake passage 6b, cancels the resonant supercharging state caused by the annular intake passage 6 and eliminates the negative pressure waves generated during the intake stroke of each cylinder 2a to 2d. is propagated to the resonance intake passage 5 through the common intake passage 6a, and is reversed into a positive pressure wave by reflection at the resonance tank 12 on the way, and the positive pressure wave is returned downstream to the other cylinders 2a to 2d. A release means 16 is configured to switch to a resonant supercharging state of the intake air. In addition, due to the arrangement positions of the first and second control valves 14 and 15 and the position of the connection part with the common intake passage 6a at the upstream end of the return intake passage 6b, the intake air generated when the first control valve 14 is closed The natural frequency of is set lower than that when the second control valve 15 is closed.

Furthermore, the two control valves 14.1 of said release means 16
5 is controlled to open and close in response to an output signal from a control unit 17 serving as a control means. This control unit 17 includes a rotation sensor 1 that detects the rotation speed of the engine 1.
The control unit 17 opens and closes the control valves 14 and 15 according to the rotation range of the engine 1, and as shown in FIG. While the first control valve 14 is closed and the second control valve 15 is opened, in the medium speed rotation range, the second control valve 15 is closed and the first control valve 14 is opened, and the engine 1 shifts to a high speed rotation range, both control valves 14 and 15 are controlled to open.

In addition, in order to smooth the transient characteristics when switching the opening and closing of the two control valves 14 and 15, each control valve 14.
．． 15 is preferably set so that the annular intake passage 6 is not airtightly closed in its closed state, but is opened at a slight angle so that the ventilation function is maintained. Also, in Figure 1,
19 is a fuel injection valve.

Therefore, in the above embodiment, the rotation speed of the engine 1 is detected by the rotation sensor 18, and the rotation speed of the engine 1 is detected by the rotation sensor 18.
The control unit 17 receiving the output signal 8 controls the opening and closing of the two control valves 14 and 15 of the release means 16. That is, as shown in FIG.
When the engine is in a low speed rotation range, the first control valve 14 is closed and the second control valve 15 is opened.

By controlling the valves 14 and 15, the annular intake passage 6 is closed at a portion upstream of the connection with each independent intake passage 7 and downstream of the connection with the upstream end of the return intake passage 6b. Accordingly, the negative pressure waves generated during the intake stroke of each cylinder 2a to 2d are propagated to the resonant intake passage 5 through the common intake passage 6a or the return intake passage 6b downstream of the first control valve 14. The resonance supercharging state of the intake air is reversed into a positive pressure wave by reflection in the resonance tank 12, and the positive pressure wave returns downstream and acts on the other cylinders 2a to 2d, or the upstream side of the intake passage 4. A resonance supercharging state is formed in which pressure waves reflected and inverted from negative to positive by the resonance tongue 12 act on the other cylinders 2a to 2d.

Conversely, in the medium speed rotation range of the engine 1, the second control valve 15 is closed and the first control valve 14 is opened. In this state, the annular intake passage 6 is connected to the second control valve 15.

That is, the upstream end portion of the return intake passage 6b is closed. Therefore, the negative pressure waves generated during the intake stroke of each cylinder 2a to 2d are propagated to the resonance intake passage 5 through the common intake passage 6a, and are reversed into positive pressure waves by reflection at the resonance tank 12 on the way. , the positive pressure wave returns downstream and acts on the other cylinders 2a to 2d, switching to a resonant supercharging state of the intake air.

Furthermore, when the engine 1 shifts to a high speed range, both the recontrol valves 14 and 15 are opened. At this time,
The annular intake passage 6 is communicated in an annular manner without being closed midway, so that after the positive pressure waves generated during the intake stroke of each cylinder 2a to 2d circulate around the annular intake passage 6, they are transferred to the other cylinders 2a. It becomes a resonance supercharging state of intake air that acts on ~2d. Therefore, as shown in FIG.
The intake air can be resonantly supercharged over a wide range from a low speed rotation range to a high speed rotation range, and the output torque of the engine 1 can be increased.

In that case, when resonantly supercharging the intake air in the low/medium speed range of the engine 1, the annular intake passage 6, which is originally intended for supercharging in the high speed range, is partially closed and the passage length is long. Since the intake passage 4 for resonance supercharging is formed, the long intake passage 4 can be formed with a compact structure, and therefore, it is possible to improve the supercharging effect of intake air and maintain the compactness of the intake device. can.

In addition, the annular intake passage 6 is opened and closed by two control valves 14 and 15 to change the resonance frequency in the low/medium speed range of the engine 1. The supercharging effect up to this point is smoothly connected, and thus the output characteristics of the engine 1 can be improved.

Note that by changing the arrangement positions of the first and second control valves 14 and 15 and the connection position of the upstream end of the return intake passage 6b with the common intake passage 6a, the first control valve 14
It is also possible to set the natural frequency of the intake air generated when the second control valve 15 is closed to be higher than that when the second control valve 15 is closed.

In that case, contrary to the above, it is necessary to close the second control valve 15 in the low speed rotation range of the engine 1 and to close the first control valve 14 in the medium speed rotation range.

Further, the second control valve 15 in the above embodiment may be omitted. However, as described above, in order to improve the output characteristics of the engine 1, it is preferable to provide the control valve 15 for supercharging the intake air in the middle speed rotation range of the engine 1 as in the above embodiment.

3 and 4 show a second embodiment (the same parts as in FIG. 1 are given the same reference numerals and detailed explanations are omitted), which is applied to a V-type six-cylinder engine. be.

That is, in FIGS. 3 and 4, 1' is the first to
6th V type 6 having six cylinders 2'a to 2'f
In the cylinder engine, the above six cylinders 2'a to 2'f
is a cylinder group consisting of a first cylinder 2'a1, a third cylinder 2'c and a fifth cylinder 2'e, and a cylinder group consisting of a second cylinder 2'b1, a fourth cylinder 2'd and a sixth cylinder 2'f. Three cylinders 2' a, 2' c, 2' e, 2' b constitute each cylinder group.
.

2' d and 2' f are 2's arranged in a V shape, respectively.
It is formed into two banks 1'a and 1'a,
The ignition order is 1st cylinder 2/a to 6th cylinder 2'
It is set in the order of f.

Each cylinder 2 L a to 2' f in each cylinder group above
An intake passage 4' is connected to the intake port 3.

The intake passage 4' has two annular intake passages 6', 6' and a resonant intake passage 5', 5' connected to the re-annular intake passage 6', 6'. 5', 5'
are connected to the air cleaner 10 by merging with each other at their upstream ends, and are configured to reflect negative pressure waves and invert them into positive pressure waves at the merging portion of the resonant intake passages 5', 5'. has been done. Two control valves 14 and 15, a first and a second control valve, are arranged in each of the annular intake passages 6'. The rest of the structure is substantially the same as that of the first embodiment.

Incidentally, the intake manifold 9' forming each annular intake passage 6' and each independent intake passage 7' of the intake passage 4' is connected to both banks 1'a of the engine 1', as shown in FIG.
, 1'a.

Further, the intake pipes 8' forming each resonant intake passage 5' protrude from between the banks ILa and IZa to one side of the engine 1', and then are bent at a substantially right angle along the side surface thereof. , With this structure, the intake pipe 8
' and the intake manifold 9' are arranged by effectively utilizing the dead space in the engine 1'.

Therefore, in this embodiment, when the engine 1' is in the low/medium speed range, the first control valve 14.14
and when the second control valves 15, 15 are closed,
In each cylinder group, negative pressure waves generated during the intake stroke of each cylinder 2/a to 2'f resonate through each common intake passage 57a or return intake passage 6'b downstream of the first control valve 14. Propagated to the intake passage 5',
It is said that the reflection at the confluence of the two resonant intake passages 5', 5' is reversed into a positive pressure wave, and the positive pressure wave returns downstream and acts on the other cylinders 2'a to 2'f. A state of resonant supercharging of the intake air is created. Also, engine 1'
In the high-speed rotation range, an annular intake passage 6' is formed in each cylinder group, and the intake air can be resonated.
The same effects as in the embodiment can be achieved.

FIG. 5 shows a third embodiment of the invention, in which an annular intake passage 6'
It is the equivalent length of .

That is, in this embodiment, the ignition order of the six cylinders 2'a to 2'f in the type 6-cylinder engine 1' is set to, for example, the order of the first cylinder 2/a to the sixth cylinder 2'f, These six cylinders 2'a to 2'f are the first cylinder 2'a and the third cylinder 2', which have non-consecutive intake orders.
c and 5th cylinder 2/e and 2nd cylinder 2'b1 4th
It is divided into two groups of cylinders, a cylinder 2'd and a sixth cylinder 2'f, and the intake systems corresponding to each cylinder group are configured to excite each other.

The return intake passage 6'b of the intake system of one group is connected to the common intake passage 6'a of the other group, thereby forming an annular intake passage 6' with a long loop length. There is.

Therefore, in this embodiment, the control valve 14 is closed in the low speed rotation range of the engine 1', and the long intake passage 4 is closed.
' is formed, and the intake air is resonantly supercharged by this intake passage 4'. On the other hand, in a high speed rotation range of the engine 1', the control valve 14 is opened to form an annular intake passage 6', and intake air can be supercharged through this annular intake passage 6'.

Therefore, the same effects as in the second embodiment can be achieved.

In addition, since the return intake passage 6'b of the intake system of one group is connected to the common intake passage 5'a of the other group, the structure remains compact and the annular intake passage with a long equivalent length is maintained. 6' is advantageous in that a good resonant supercharging effect can be obtained in the low speed rotation range of the engine 1'.

(Effects of the Invention) As explained above, according to the present invention, the intake ports of each cylinder are connected. In an engine intake system that generates resonance supercharging of intake air through a resonant annular intake passage without a volume expansion chamber, a predetermined portion of the resonant annular intake passage is partially closed in the low engine speed range. By changing the annular intake passage into one long intake passage, it is possible to form an intake passage for resonance supercharging in the low speed range of the engine with a compact structure. It is possible to downsize the intake system of an engine that performs this, and it is particularly effective for application to a vehicle-mounted engine.

[Brief explanation of drawings]

1 and 2 show a first embodiment of the present invention. FIG. 1 is an explanatory diagram showing the overall configuration of an intake system, and FIG. 2 shows changes in engine output torque with respect to opening and closing operations of control valves. FIG. 3 is a characteristic diagram showing characteristics. 3 and 4 show a second embodiment, FIG. 3 is a view corresponding to FIG. 1, and FIG. 4 is a perspective view showing the arrangement structure of the resonance annular intake passage. FIG. 5 is a diagram corresponding to FIG. 1 showing the third embodiment. 1.1'...Engine, 2a to 2d, 2'a
~2' f... Cylinder, 6.6', 6'... Annular intake passage, 6a, 6' a, 5' a-... Common intake passage, 6b, 6'b, 6'b...・Return intake passage, 7,
7'...Independent intake passage, 14.15...Control valve, 16...Release means, 17...Control unit.

Claims (1)

[Claims] (1) An intake system for an engine, which has a resonant annular intake passage connected to the intake ports of each cylinder and has no volume expansion part, and which causes resonant supercharging of intake air through the annular intake passage, The annular intake passage includes a common intake passage connected to the intake port of each cylinder via an independent intake passage;
A return intake passage, one end of which is connected to the upstream end of the common intake passage, and the other end of which is connected to the downstream end of the common intake passage, and the return intake passage is located upstream of the connection with the independent intake passage. a release means for closing a common intake passage downstream of the connection portion with the upstream end to release resonance supercharging by the annular intake passage; and control to operate the release means in a low rotational speed range of the engine. An intake system for an engine, characterized in that it is equipped with a control means.