JP2609282B2 - Engine intake system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an intake device for an engine in which intake air is resonantly supercharged by an annular intake passage having no volume expansion portion.

(Prior Art) Conventionally, there have been known various ones in which the filling efficiency is increased by a dynamic effect of intake air taken into a combustion chamber in a cylinder of an engine to increase the output torque of the engine. As an example, Japanese Patent Publication No. Sho 60-14169 discloses an intake passage in a multi-cylinder engine which is connected to a group of cylinders in which cylinders in which the intake order (ignition order) is not continuous belong to the same group. Divided into two intake passages, each of which is constituted by an enlarged chamber to which an upstream end of a branch portion of the intake manifold is connected, and a resonance passage connected to the enlarged chamber, and an upstream end of the resonance passage is upstream. A switching device that communicates with the side collecting chamber and switches the two intake passages into a communicating state or a communication blocking state in the enlarged chamber; The negative pressure wave generated in the process is reflected by the upstream collecting chamber and inverted to a positive pressure wave, and the inverted pressure wave exerts a resonance supercharging effect of intake air in a relatively low rotation range. On the other hand, when the two intake passages are communicated with each other, the reverse reflection position of the intake pressure wave is brought closer to the intake port, the natural frequency of the intake pressure vibration is increased, and the resonance supercharging effect is obtained in the high speed rotation range. Has been made.

Further, in what is disclosed in JP-A-56-52522,
A loop is formed in the intake manifold connected to the air cleaner so that the intake air flows in the loop in one direction, and the intake pipe branched and connected to the intake manifold is directed to the intake flow direction in the loop with respect to the manifold. By making an acute angle with the intake air, the intake flow rate in the loop is used to increase the intake charging efficiency by the inertia force.

(Problems to be Solved by the Invention) However, in the former case, since a large-volume expansion chamber is provided in the gathering portion of the intake manifold branches, the intake system becomes large, and a large installation space is required. And so on.

Therefore, in the latter technique, attention is paid to the point that a loop portion is formed in the intake manifold, and each intake port of two cylinder groups in which cylinders in which the intake order is not continuous is the same group is connected to a common resonance port without an expansion chamber. A portion communicating with each of the intake ports of one cylinder group and a portion communicating with each of the intake ports of the other cylinder group extend in two directions. The length of the two-sided communication path between the two cylinder groups is formed to be sufficiently larger than the length between the intake ports of adjacent cylinders of the same cylinder group. The positive pressure wave generated near the intake port at the end of the intake stroke is made to make a round of the resonance annular passage to act on the intake ports of the cylinders of the same cylinder group, effectively exhibiting the dynamic effect of intake. Sesetsu , It is conceivable to make compact the size and the required expansion chamber intake.

Furthermore, not only the intake supercharging effect of the annular intake passage but also the intake port of each cylinder is connected to an intake passage having no capacity expansion chamber such as a surge tank, and the resonance frequency of the intake air in the intake passage is connected. By setting the length of the intake passage so that the engine speed becomes a specific rotation range (for example, a low speed rotation range) of the engine, it is possible to supercharge the intake air by its resonance effect.

By the way, in such an intake device, a space is required in the longitudinal direction of the engine of the intake device, and the front engine
In the case of a front-drive vehicle, it is relatively easy to place it in the longitudinal direction of the engine, for example, because space can be secured above the transmission case, but in the case of a front-engine or rear-drive vehicle, the dash panel limits the space behind the engine. Received, can not be placed well.

SUMMARY OF THE INVENTION An object of the present invention is to reduce the size of the entire intake system of an engine in which resonance supercharging of intake air is performed by the above-described long annular intake passage.
The goal is to make it available for rear-drive vehicles.

(Means for Solving the Problems) In order to achieve the above object, a solution for the invention of claim 1 is to arrange cylinders in which the ignition order is not continuous into the same group.
The respective intake ports of the two cylinder groups are respectively connected to the first and second collective intake passages, and the two collective passages are communicated upstream and downstream to form an annular intake passage without a volume expansion portion,
An intake device of an engine in which intake air is resonantly supercharged by the annular intake passage is premised on that an upstream communicating portion of the two combined intake passages communicates with the two combined intake passages from above. It is assumed that the downstream communication portion is folded upward and is disposed close to the upstream communication portion.

Here, in the invention of claim 2, the invention is applied to a V-type six-cylinder vertical engine, and in the invention of claim 3, the upstream communication portion and the downstream communication portion are connected by a rib. Shall be.

(Operation) According to the first to third aspects of the present invention, the upstream communication part is connected to the collective intake passage from above, while the downstream communication part is folded back and arranged close to the upstream communication part. Therefore, the upstream and downstream communication portions are both close to each other and are located above the collective intake passage. As a result, compactness is achieved in the cylinder row direction without increasing the vertical height too much. Further, according to the third aspect of the invention, the upstream communication portion and the downstream communication portion can be integrally formed.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

1 to 3 are a plan view, a front view, and a side view, respectively, showing a specific structure of an intake device for an engine, and FIG. 4 is a schematic plan view showing an entire configuration of the intake device for the engine.

Reference numeral 1 denotes a fuel injection V-type six-cylinder vertical engine having six first to sixth cylinders 2a to 2f.
The order of ignition of 2f is the same as the cylinder number of the first cylinder 2a to the sixth cylinder.
The order is set to 2f. And these six cylinders
Reference numerals 2a to 2f denote three first, third and fifth cylinders 2a, 2c and 2e, and second, fourth and sixth cylinders 2b, 2d,
2f, each of which is divided into two cylinder groups, each of which comprises three cylinders 2a, 2c, and 2e, which are sequentially formed in one bank 1a of the V-shaped engine 1;
The three cylinders 2b, 2c, 2f constituting the other cylinder group are sequentially formed in the other bank 1a.

An intake passage 4 having no volume expansion chamber such as a surge tank is connected to the intake ports of the cylinders 2a to 2f. The intake passage 4 includes an independent intake passage 5 connected to the intake port of each of the cylinders 2a to 2f, an annular intake passage 6 as a resonance intake passage connected to an upstream end of each of the independent intake passages 5, The common intake passage 10 is connected to the intake passage 6, and an air flow meter 11 and an air cleaner 12 are sequentially arranged upstream of the common intake passage 10.

The annular intake passage 6 includes two collective intake passages 7, 7 to which the respective cylinders 2a to 2f independent intake passages 5, 5 in the two cylinder groups are connected, and two collective intake passages 7, 7, respectively. Third
And the portion between the fifth cylinders 2c, 2e and the fourth and sixth cylinders 2d,
An upstream communication passage 8 which communicates with a portion between 2f and extends upward, and an intermediate portion to which the downstream end of the common intake passage 10 is connected; The second cylinder 2a,
A downstream communication path 9 extends upward while communicating the ends on the 2b side.

The downstream communication passage 9 is turned upward and is located together with the upstream communication passage 8 above the collective intake passages 7, and the curved intermediate portion thereof is a third and a third part toward the center in the cylinder row direction. It is arranged to extend to the vicinity of the fourth cylinders 2c and 2d and to approach the upstream communication passage 8. Thus, the present invention can be applied to a front engine / rear drive vehicle without being restricted by the dash panel A.

A part of the upstream communication path 8 and a part of the downstream communication path 9 are formed as a unitary body 31 integrally formed.
The connecting flange 31a for connection with the horizontal surface,
The joint flange 31b for connection with the intake pipe 32 is vertical. In order to integrally mold as a unit body 31,
The pipes forming the two communication passages 8, 9 are connected by a rib 31c.

In addition, the inlet portion of the upstream communication passage 8 into the collective intake passages 7, 7 is curved toward the center in the cylinder row direction so that the intake air uniformly enters all the cylinders from the upstream communication passage 8.

Further, throttle valves 12A and 12B for adjusting the intake air amount are provided in the middle of the upstream communication path 8. A fuel injection valve 13 for injecting and supplying fuel is disposed in each of the independent intake passages 5. Reference numeral 33 denotes a Ferdis pipe for supplying fuel to the fuel injection valve 13.

In addition, control valves 14, 14 made of butterfly valves are arranged near the connection between the downstream communication passage 9 and the collection air passages 7, 7. By controlling the opening and closing of the control valves 14, 14, the resonance supercharging state of the intake air and its resonance frequency change.

The operation of each of the fuel injection valves 13 is controlled by a control unit 14. The control unit 14 receives an engine speed signal and an intake negative pressure signal. The control unit 14 calculates an intake air amount to the engine 1 based on the intake negative pressure and the engine speed.
The fuel injection amount corresponding to the calculated intake air amount is determined, the command signal is output to each fuel injection valve 13, and the fuel is injected and supplied to the combustion chamber in each of the cylinders 2a to 2f. ing.

The control unit 17 opens and closes the control valves 14 and 14 via an actuator 15 according to the engine speed. As shown in FIG.
While the engine is closed, the engine is opened in the high rotation range, and the engine output is improved by the supercharging effect.

By the way, the independent intake passage 7 is set to be short, but a specific setting thereof may satisfy the following expression (1) in order to sufficiently obtain a resonance effect in a high engine speed region.

Where: Mmax = allowable engine speed (rpm) θ = intake port open period (crank angle, deg) a = sonic speed Vm = average combustion chamber volume during intake port open period d: diameter of independent intake passage l: independent intake Length of the passage (length to the intake port) When the above equation (1) is described, according to Helmholtz's resonance equation, Is satisfied, it is known that resonance supercharging can be obtained. Then, from the relationship of ν = (N / 60) × (360 / θ) (3) N = engine rotation speed (rpm), the expression (3) is substituted into the expression (2) to obtain the expression (2). A synchronous equation (4) for obtaining resonance supercharging using the engine speed N instead of the equation is obtained.

In the above equation (4), by replacing N with Nmax and making it sufficiently larger than the right term, resonance supercharging can be obtained in a high engine speed range. And
It is understood that the length of the independent intake passage may be shortened in order to sufficiently increase the right term of the equation (4) (the right term of the equation (1)).

In addition, in the length of each portion in the annular intake passage 6, the length L1 of the upstream communication passage 8 to which the cylinders 2e and 2f at the upstream end are connected, and the cylinders 2a and 2b at the downstream end are connected. It is desirable that the length L2 of the downstream communication passage 9 and the length L3 of the portion where the adjacent cylinder communicates satisfy the following expression (5).

L1 = L2> L3 (5) Therefore, when the control valve 14 is in the low rotation range where it is closed, the downstream communication path 9 is closed.
A negative pressure wave generated in the intake stroke of each of the cylinders 2a to 2f passes through the collective intake passages 7,7 or the upstream communication passages 8,8 to the common intake passage.
The air is propagated to the air cleaner 11 and is reflected by the air cleaner 11 into a positive pressure wave, which returns to the downstream side and acts on the other cylinders 2a to 2f, thereby forming a resonance supercharging state of the intake air. .

Further, in the high rotation range where the control valve 14 is opened, the annular intake passage 6 is annularly communicated without being closed halfway, so that the cylinders 2a to 2c in the cylinder group in which the ignition order is not continuous.
In the vicinity of the intake port 2f, a pressure wave, which is a pressure vibration of the intake air which becomes a positive pressure at the end of the intake stroke of each of the cylinders 2a to 2f, is provided in the upstream and downstream communication passages 8, 9 in two different directions. 6 and travels substantially once around the annular intake passage 6, and then acts on the intake ports of the other cylinders 2a to 2f of the same cylinder group to produce a resonance state of the intake air. By this resonance state, intake air can be supercharged.

6 to 8 show another embodiment of the present invention, that is, an embodiment applied to an in-line four-cylinder engine.

In the case of this embodiment, the first and fourth cylinders 21 of the engine 21
a, 21d intake ports, independent pipes 24, which constitute independent supply passages,
A first collecting pipe 22 (first collecting intake passage) connected via the first connecting pipe 24 and an intake port of the second and third cylinders 21b, 21c are connected via independent pipes 25, 25 forming an independent intake passage. And a downstream communication pipe that communicates the ends of the first and second collection pipes 22, 23 on the third and fourth cylinders 21c, 21d side. 26 (downstream communication path) is folded upward, while the first and second collection pipes 22 and 23 have
The ends of the cylinders 21a and 21b are connected to the upstream communication pipes 27a and 27b from above.
(Upstream communication passage), and the two upstream communication pipes 27a,
The upstream end of 27b is connected to an intake pipe 28 constituting a common intake passage. Thus, the downstream communication pipe 26 is folded back so as to be disposed close to the upstream communication pipes 27a and 27b. The above-mentioned two collecting passages (collecting pipes 22 and 23), the downstream communication path (downstream communication pipe 26), and the upstream communication path (upstream communication pipe 27)
a, 27b) form an annular intake passage.

The two communication pipes 26, 27a, 27b are integrally formed (that is, the downstream communication pipe 26 is connected to the upstream communication pipe 27b), and the first assembly 31 is formed. 22, 23 and the independent tubes 24, 24, 25, 25 are integrally formed to form a second assembly 32, which is formed by a flange portion 31.
a, 32a. 33 is a throttle valve, 34
Is a control valve for resonance supercharging of intake air.

(Effects of the Invention) As described above, according to the first to third aspects of the present invention,
In an intake device for an engine in which intake air is resonantly supercharged by an intake passage having no volume expansion chamber, the upstream communication portion and the downstream communication portion are disposed close to and above the collective intake passage, so that the overall length of the engine is reduced. The overall height is compact, and it can be mounted on front engine and rear drive vehicles.

[Brief description of the drawings]

1 to 4 show an embodiment in which the present invention is applied to a six-cylinder V-type engine, and FIGS. 1 to 3 each show an intake system of the engine. FIG. 4 is a plan view, a front view, and a side view showing a specific structure of the engine, FIG. 4 is a schematic plan view showing the entire structure of an intake device of the engine, and FIG.
The figures show the relationship between the engine speed and the output. FIGS. 6 to 8 are a front view, a side view and a schematic plan view of an embodiment applied to an in-line four-cylinder engine. 1,21 ... Engine, 2a-2f, 21a-21d ... Cylinder, 5 ...
Independent intake passage, 6 ... Annular intake passage, 7 ... Collective intake passage, 8 ... Upstream communication passage, 9 ... Downstream communication passage, 14, 34
…… Control valve, 17 …… Control unit, 22, 23 ……
Collecting pipe, 24,25 …… Independent pipe, 26 …… Downstream communication pipe, 27a, 2
7b …… Upstream communication pipe

Claims (3)

(57) [Claims] An intake port of two cylinder groups in which cylinders whose ignition order is not continuous is connected to first and second collective intake passages, respectively, and both collective intake passages are communicated upstream and downstream. An intake device for an engine, wherein an annular intake passage having no volume expansion portion is formed, and intake air is resonantly supercharged by the annular intake passage. An intake device for an engine, wherein the downstream communication portion is folded upward and is disposed adjacent to the upstream communication portion. 2. An intake system for an engine according to claim 1, wherein said engine is a V-type six-cylinder vertical engine. 3. The intake system for an engine according to claim 1, wherein the upstream communication portion and the downstream communication portion are connected by a rib.