JPH0354318A - Intake device of multiple cylinder engine - Google Patents

Abstract

PURPOSE:To eliminate the resonance effect except an intake resonance synchro- rotation range by mutually communicating independent intake passages with communication passages, and mutually connecting the respective communication passages corresponding to respective cylinders via an opening and closing valve. CONSTITUTION:In a V type six-cylinder engine 1, cylinders 3a, 3b are constituted at cylinders 2a, 2c, 2e, and 2b, 2d, 2f which are not close to each other in ignition order. Respective independent intake passages 5a, 5b which are communicated with the cylinders 2a, 2c, 2e and 2b, 2d, 2f of the cylinders 3a, 3b are communicated mutually by communication passages 14a, 14b. The communication passages 14a, 14b which correspond to respective cylinders 3a, 3b are connected by means of a connection passage 15 which opens and closes by an opening and closing valve V2. Consequently, a connection passage length L2 is shorter than the shortest length between the cylinder, and torque decrease by intake resonance effect except a resonance synchro-rotation range of an engine 1 is effectively eliminated. Intake air is thereby supercharged by only inertia effect so as to obtain torque improvement effect surely.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an intake system for a multi-cylinder engine, and particularly to one that supercharges intake air using an inertial effect and a resonance effect.

(Conventional technology) Conventionally, technology has been used to increase the filling efficiency of the intake air and improve the output torque of the engine by supercharging the intake air supplied to the cylinders of the engine using inertia effects and resonance effects. is known.

When supercharging intake air by inertial effect, when a negative pressure wave of intake air is generated in the intake boat as the intake valve opens at the beginning of the intake stroke of each cylinder in a predetermined engine rotation range (synchronous rotation range), This intake negative pressure wave is propagated at the speed of sound toward the upstream side within an independent intake passage connected to the intake boat, and this negative pressure wave is reversed to a positive pressure wave in a predetermined volume. Furthermore, this positive pressure wave is propagated downstream along the same path at the speed of sound, reaching the intake boat of the same cylinder at the end of the intake stroke just before the intake valve closes, and this positive pressure wave pushes the intake air into the combustion chamber. The purpose is to increase the filling efficiency.

On the other hand, when intake air is supercharged by resonance effect, multiple cylinders of the engine are divided into cylinders with discontinuous ignition timing (cylinders with non-adjacent ignition order) and grouped into multiple cylinder groups, and each cylinder group is The independent intake passages of a plurality of cylinders are assembled into one collective intake passage (resonant intake passage) at the upstream end, and a pressure inversion section is provided at a predetermined position of this collective intake passage. By matching the phase of the basic pressure wave of intake air generated in the intake boat of each cylinder of the cylinder group in the synchronized rotation range of the engine and the reflected pressure wave reversed at the pressure inversion section, the pressure inversion section and each cylinder are The pressure waves of the intake air that propagate back and forth between the joints resonate within the collective intake passage. This resonance generates a resonance pressure wave with a large amplitude due to pressure vibrations that occur individually in each cylinder, and this resonance pressure wave pushes intake air into the combustion chamber of the cylinder to increase charging efficiency. .

By the way, when supercharging is performed using the above-mentioned resonance effect, when the engine rotation speed reaches the tuned rotation speed determined by the intake passage length and the cross-sectional area of the intake passage, a resonance state occurs and a torque improvement effect can be obtained. However, on the other hand, when the engine speed increases beyond the tuning speed, the torque suddenly decreases due to the pressure wave propagation delay due to the passage length.

As an engine intake system that eliminates the drop in torque in rotation ranges other than the synchronized rotation speed due to such resonance effects,
Conventionally, in JP-A-62-101820, an independent intake passage communicating with each cylinder is provided for a multi-cylinder engine in which a plurality of cylinders are divided into two groups of first and second cylinders with non-consecutive ignition timings. The main independent intake passage has a relatively long passage length and a relatively small passage cross-sectional area, and the bypass independent intake passage has a relatively short passage length and a relatively large passage cross-sectional area and is opened and closed by a switching valve, The upstream ends of the main independent intake passages of the cylinders in the first cylinder group and the upstream ends of the bypass independent intake passages of the cylinders in the second cylinder group are used as the first distribution chamber, and the upstream ends of the main independent intake passages of the cylinders in the second cylinder group and the The upstream ends of the bypass independent intake passages of the cylinders in the cylinder group were respectively connected to the second distribution chamber, and both distribution chambers were communicated through a communication passage opened and closed by an on-off valve, and the upstream ends of both distribution chambers were communicated with the collecting chamber. something is known.

In this system, the pressure waves of the intake air resonate between the cylinders of each cylinder group and the gathering chamber in the low speed range of the engine, and an intake resonance effect can be obtained, and in the middle speed range of the engine, the open/close valve By opening the distribution chambers to communicate with each other through a communication passage, the pressure waves of intake air generated in the cylinders of both cylinder groups cancel each other out in the distribution chambers, suppressing the resonance effect, and the main independent intake passage provides an inertial effect. Furthermore, in the high rotation range, the switching valve is opened to obtain an inertia effect through the bypass independent intake passage.

(Problem to be Solved by the Invention) However, in this conventional system, the upstream ends of the main independent intake passages of the cylinders of the first cylinder group and the upstream ends of the bypass independent intake passages of the cylinders of the second cylinder group are connected to the first distribution chamber. , the upstream ends of the main independent intake passages of the cylinders in the second cylinder group and the upstream ends of the bypass independent intake passages of the cylinders in the first cylinder group are connected to the second distribution chamber, so the communication path between both chambers is long. Become. For this reason, in the high speed range of an engine with the communication passage open, an unintended resonance effect occurs between the communication passage and each cylinder, that is, the communication passage becomes a pressure reversal part, and it is difficult to effectively eliminate the resonance effect. There is a possibility that this will happen.

The present invention has been made in view of the above points, and its purpose is to make the resonance effect effective in the engine rotation range outside the resonance synchronized rotation range of the intake air by changing the structure of the above-mentioned intake passage. The purpose is to solve this problem by making it possible to supercharge the intake air only by the inertial effect, thereby reliably improving the engine torque.

(Means for Solving the Problem) In order to achieve the above object, in the invention according to claim (1), a cylinder group is constituted by cylinders whose ignition order is not adjacent to each other,
Cylinder l of the cylinder group: The communicating independent intake passages are communicated with each other by a communication passage, and the communication passages corresponding to both cylinder groups are connected with each other via an on-off valve.

Specifically, in this invention, a plurality of cylinders are divided into a plurality of cylinder groups, which are cylinders whose ignition order is not adjacent to each other, and the cylinders in each cylinder group are connected to each other through independent intake passages. The premise is that the intake system of a multi-cylinder engine is connected to the Yum chamber.

A communication passage for each cylinder group that communicates the independent intake passages corresponding to the cylinders of each cylinder group, a connection passage that connects the communication passages, and an on-off valve that opens and closes the connection passage are provided.

Furthermore, the length of the connection passage is made shorter than the shortest distance between cylinders in each cylinder group (distance between adjacent cylinders).

(Function) With the above configuration, in the invention according to claim (1), the on-off valve closes and communication between the communication passages is cut off in a predetermined operating range of the engine. In this state, a resonance effect occurs in which the intake pressure waves resonate between the cylinders in each cylinder group and the connection part of the communication passage to the connection passage, and an inertia effect occurs in the independent intake passage of each cylinder in each cylinder group. , the intake air is supercharged by this resonance effect or inertia effect.

On the other hand, when the engine changes from the above operating range, the on-off valve opens and the communication passages are communicated with each other through the connection passage. At this time, the same inertial effect as above is obtained, but the communication between the communicating passages through the connecting passage forms a large volume section consisting of both communicating passages or the connecting passage, and this volume section strengthens the above-mentioned inertial effect. . At the same time, the resonance effect of the intake air disappears due to the communication of the communication passage, and the reduction in torque due to the resonance effect disappears. Therefore, the torque decrease is suppressed by the amount of the disappearance of this resonance effect, and therefore, it is possible to obtain the torque improvement effect due to the inertia effect.

In this case, since the length of the connecting passage is shorter than the shortest distance between the cylinders of each cylinder group, the pressure waves of the intake air resonate with the connecting passage as an intake gathering point, which means that a resonance effect occurs at an engine speed other than the intended one. Therefore, the above-mentioned resonance effect is effectively eliminated, and the torque improvement effect due to the inertial effect is reliably obtained.

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

FIG. 1 shows the overall configuration of an embodiment of the present invention, and 1 indicates the first to
A V-type six-cylinder engine having six six cylinders 2a to 2f, the engine 1 has opposing first and second banks la lb, and a first bank 1a to 2f.
There are three cylinders: the first cylinder 2a, the third cylinder 2C, and the fifth cylinder 2e.
In addition, in the second bank 1b, three cylinders, a second cylinder 2b, a fourth cylinder 2d, and a sixth cylinder 2f, are formed in series at equal intervals L2. And the first
~The sixth cylinders 2a to 2f are set to be ignited in order of cylinder number, and the three cylinders 2a and 2 of the first bank 1a
c, 2e, the first cylinder group 3a whose ignition order is not adjacent
However, similarly, the three cylinders 2b. of the second bank 1b. 2d
, 2f, the second cylinder groups 3b whose ignition order is not adjacent are respectively configured.

Reference numeral 4 denotes an intake passage that supplies intake air to each of the cylinders 2a to 2f.
independent intake passages 5a, 5a, . . . , three second independent intake passages 5b, 5b, . First independent intake passage 5a. , 5a, . . . and a second independent intake passage 5b.
, 5b, . These are both banks 1 of engine 1.
The first and second independent intake passages 5a are arranged between the first and second independent intake passages 5a and lb.
, 5b extend in a direction perpendicular to the banks la, lb and intersect with each other. In addition, the first and second volume chambers 6
a and 6b have a part of the intake passage 4 (intake pipe) with a larger cross-sectional area than the other part, and are arranged parallel to the banks la and lb in a state where they face each other between the two banks la and lb, Each of the upstream ends thereof is connected to a chirping intake passage 7a, 7b. The upstream ends of both resonance intake passages 7a and 7b are brought together and connected to the downstream end of a common intake passage 8, and the upstream end of the common intake passage 8 is connected to an air cleaner 9. An air flow meter 10 for detecting the amount of intake air is installed in the middle of the common intake passage 8 for each resonant intake passage 7a.
, 7b are synchronized with each other at the downstream ends of the resonant intake passages 7a, 7b.
7b Throttle valve 11.1 that opens and closes (intake passage 4)
1 are arranged respectively.

The intermediate portions of both the resonance intake passages 7a and 7b are communicated with each other by a first communication passage 12, and a normally closed first resonance variable valve v1, which is an on-off valve that opens and closes the communication passage 12, is disposed in the communication passage 12. has been done.

Further, the downstream ends of both volume chambers 6a and 6b are communicated with each other by a second communication passage 13, and this communication passage 13 has a normally closed second resonance variable valve that is comprised of a pair of on-off valves that open and close the communication passage 13. Valves V2 and V2 are provided.

Furthermore, the three first independent intake passages 5a, 5a, . are communicated with each other by a first independent intake passage communication passage 14a extending in the longitudinal direction. On the other hand, similarly, the three second independent intake passages 5b, 5b, . They are communicated with each other by a second independent intake passage communication passage 14b that extends into the second independent intake passage. The communication portion between the first independent intake passage communication passage 14a and each independent intake passage 5a, and the communication portion between the second independent intake passage communication passage 14b and each independent intake passage 5b are opened and closed in synchronization with each other. A normally closed inertia variable valve V,,v, consisting of a valve is disposed, and when this valve V1 is opened, three first independent intake passages 5a, 5a, . . .
- The second independent intake passages 5b, 5b, . . . communicate with each other.

Furthermore, the two independent intake passage communication passages 14a, 14b
are connected by a connecting passage 15 in the middle thereof, and the passage length L1 of this connecting passage 15 is the shortest distance L2 ( The length is shorter than the distance between adjacent cylinders (#).

Further, the connection passage 15 is provided with a resonance effect canceling valve V2 consisting of an on-off valve that opens and closes the connection passage 15. The first variable resonance valve Vl, the second variable resonance valve v2, the variable inertia valve V1, and the resonance effect canceling valve V2 are opened in order from the low speed range to the high speed range of the engine 1, as shown in FIG. It is made to be praised.

Next, to explain the operation of the above embodiment, as the rotational speed of the engine 1 increases, the first resonance variable valve v
1. Second resonance variable valve V,? , the variable inertia valve v1, and the resonance effect canceling valve V2 are opened in order. That is, as shown in FIG. 2, in a low rotation range where the rotation speed of the engine 1 is low, all valves v1, 2, V1, and V2 are closed. In this state, at a predetermined rotational speed (tuned rotational speed) of the engine 1, the cylinders 2a, 2c, and 2 of each cylinder group 3a (or 3b)
A reflected pressure wave in which the fundamental pressure wave of the intake air generated at the intake port e (or 2b, 2d, 2f) is reflected at the upstream end gathering part (connection part with the common intake passage 8) of the resonant intake passage 7a (or 7b) The intake pressure wave resonates in phase with the phase of each cylinder 2a, 2c, 2e (or 2b, 2d
, 2f), a resonant pressure wave with a large amplitude is generated by the pressure vibrations that occur individually for each cylinder 2a, 2C, 2e (or 2b, 2d, 2f).
The fuel is pushed into the combustion chamber within the combustion chamber, increasing its charging efficiency. As a result, the output torque of the engine 1 increases as shown by the solid line in the figure. Further, in this rotation range, the inertia effect of the intake air due to the independent intake passages 5a and 5b does not occur.

Further, when the engine speed increases, only the first resonance variable valve v1 opens, and the first communication passage 12 opens. With this opening of the communication passage 12, the phase of the fundamental pressure wave of intake air during resonance tuning is changed to the reflected pressure wave reflected from the upstream end gathering part of the resonance intake passage 7a (or 7b) at the first communication passage 12 which is closer to it. The phase of the motor becomes consistent with that of the motor, and as a result, the tuned rotational speed increases. Therefore, the charging efficiency of the intake air is similarly increased, and the output torque of the engine 1 can be increased as shown by the dotted line in FIG.

When the engine speed further increases to a medium speed range, the second variable resonance valves V2 and V2 are opened in addition to the first variable resonance valve vl, and the second communication passage 13 is opened. In this state, the phase of the basic intake pressure 1 is the second communication path 1.
At 3, the phase of the reflected pressure wave becomes equal to 1, and the phase of the reflected pressure wave is 0, and the tuned rotation speed further increases. This increases the charging efficiency of the intake air, making it possible to increase the output torque of the engine 1 as shown by the broken line in FIG.

Furthermore, when the engine speed increases, the six variable inertia valves V,, v,... open, and the opening of the variable inertia valve V1 causes the first independent intake passages 5a, 5a,...
are connected to each other by the first independent intake passage communication passage 14a, and the second
The independent intake passages 5b, 5b, . . . are connected to the second independent intake passage communication passage 1. 4b, respectively. In this engine rotation range, each of the cylinders 2a, 2c. 2e (
2b, 2d, 2f) and the second communication path]3, the output torque of the engine 1 due to this resonance effect is However, this time each cylinder 2a, 2c, 2
e (or 2b, 2d, 2f) and the communication path 14a (or 14
b) At the same time, an inertial effect of intake air occurs in the independent intake passages 5a and 5b.

That is, the intake negative pressure wave generated at the intake port at the beginning of the intake stroke of each cylinder 2a to 2f propagates at the speed of sound toward the upstream side within the independent intake passages 5a and 5b, and this negative pressure wave is transmitted to the communication passage 14.
It is reversed to a positive pressure wave at points a and 14b.

Then, this positive pressure wave propagates downstream along the same path at the speed of sound and reaches the intake ports of the same cylinders 2a to 2f at the end of the intake stroke, and this positive pressure wave pushes the intake air into the combustion chambers in the cylinders 2a to 2f. , its filling efficiency increases. The filling efficiency of intake air due to this inertial effect is large, and this causes the second
As shown by the dashed line in the figure, the output torque of the engine 1 can be increased.

Then, when the engine 1 moves to a high speed range, the same inertial effect as described above is obtained, but at this time, the resonance effect canceling valve V2 opens and the first and second independent intake passage communication passages 14a
, 14b communicate with each other, and with this communication, both communication passages 14
A, 14b or the connecting passage 15 form a large volume, which eliminates the resonance effect of the intake air described above and enhances the inertial effect. Therefore, the influence of the resonance effect on the inertia effect of intake air is eliminated, and the inertia effect is fully utilized, so that the torque improvement effect due to the inertia effect can be obtained as shown by the two-dot chain line in FIG.

At that time, the length L1 of the connection passage 15 is set for each cylinder 7ET3.
a (or 3b) cylinder 2a. 2c, 2e (or 2b,
2d, 2f), the pressure waves of the intake air resonate with the connecting passage 15 as the intake air collection point.In other words, the resonance effect does not occur at engine speeds other than the intended one, and therefore the above-mentioned resonance effect does not occur. can be effectively eliminated, and the torque improvement effect due to the inertia effect can be reliably obtained.

In the above embodiment, the volume chambers 6a and 6b may be formed by surge tanks. Further, in this case, instead of arranging the volume chambers 6a and 6b facing each other between both banks LALB, the inside of one surge tank may be partitioned into two chambers by a partition wall to form both volume chambers.

Furthermore, although the present invention is applied to a V-type 6-cylinder engine, the present invention is applicable to V-type engines such as 8-cylinder, 9-cylinder, and 12-cylinder engines, and other types of multi-cylinder engines such as in-line engines. It can also be applied to

(Effects of the Invention) As explained above, according to the invention related to visit item (1), a plurality of cylinders are grouped into cylinders with discontinuous ignition waiting periods, and the cylinders in each cylinder group are connected to each other through independent intake passages. In a multi-cylinder engine that is connected to a volume chamber, the independent intake passages of each cylinder group are communicated with each other by a communication passage, and the communication passages are connected by a connection passage that is opened and closed by an on-off valve, and the length of the connection passage is By making the shortest distance between the cylinders in the cylinder group shorter than the shortest distance between the cylinders in the cylinder group, the reduction in torque due to the resonance effect of the intake air in operating ranges other than the resonance synchronized rotation range of the engine is effectively eliminated, and intake overload is suppressed only by the inertia effect. It is possible to reliably obtain the torque improvement effect due to the inertia effect.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a plan view schematically showing the overall configuration of an engine intake system, and FIG. 2 is a characteristic diagram showing the characteristics of engine output torque changes as each valve opens and closes. It is. 1...Engine 2a to 2f...Cylinder 3a, 3b...Cylinder group 5a, 5b...Independent intake passage 6a, 6b...Volume chamber 12...First communication passage 13...No. Two communication passages 14a, 14b...Independent intake passage communication passage (communication passage) 1
5... Connection passages Vl, V2... Variable resonance valve V1... Variable inertia valve v2... Resonance effect elimination valve (opening/closing valve) L1... Connection passage length L2... Shortest length between cylinders Rihito Sayo Patent attorney Hiroshi Maeda (and 2 others) Figure 2

Claims (1)

[Claims] (1) A multi-cylinder cylinder in which multiple cylinders are divided into multiple cylinder groups with non-adjacent firing orders, and each cylinder in each cylinder group is connected to the volume chamber of each cylinder group via an independent intake passage. In an engine intake system, there is a communication passage for each cylinder group that communicates the independent intake passages corresponding to the cylinders of each cylinder group, a connection passage that connects the communication passages, and an on-off valve that opens and closes the connection passage. An intake system for a multi-cylinder engine, characterized in that the length of the connecting passage is shorter than the shortest distance between the cylinders of each cylinder group.