JP2711872B2 - Multi-cylinder engine intake system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to an intake device for a multi-cylinder engine, and more particularly to an improvement in a passage configuration of an intake passage.

(Prior Art) An engine for a vehicle may be provided with an exhaust turbocharger that supercharges intake air by using exhaust energy in order to improve output performance. Also, apart from this exhaust turbocharger, as described in, for example, Japanese Patent Publication No. 60-14169, a dynamic effect such as an inertial supercharging effect of intake air is used to improve the intake charge amount. Is known. This is such that the propagation period of the pressure wave generated in the intake passage is synchronized with the opening / closing timing of the intake valve to generate the pushing action of the intake air. In order to synchronize with the opening / closing timing of the intake valve, the length of the intake passage corresponding to the cycle may be changed according to the engine speed, as described in the above-mentioned publication.

(Problems to be Solved by the Invention) By the way, in the exhaust turbocharger, a sufficient supercharging effect cannot be obtained in a low rotation region of the engine, and an output torque is reduced due to a response delay when accelerating from a low rotation region. There is a disadvantage that it does not rise quickly. Therefore, in the engine equipped with the exhaust turbocharger, it is possible to improve the output performance at the time of acceleration from the low rotation region or the low rotation region by further utilizing the dynamic effect of the intake air as described above. It is considered. However, in this case, the following problem occurs.

In other words, in order to utilize the dynamic effect of intake air in a low rotation region where the exhaust turbocharger does not sufficiently exert a supercharging effect, it is necessary to tune the propagation cycle of the pressure wave in the intake passage to a low engine speed. Therefore, the intake passage must be made sufficiently long. As a result, the entire engine becomes large, and it becomes difficult to store the engine particularly in the case of an engine for a vehicle in which the engine must be stored in a limited space of the engine room. The layout of the car and the design of the car body around the engine room will be severely restricted.

This problem also occurs in an engine that does not include an exhaust turbocharger when the dynamic effect of intake air is to be used in a low rotation speed region.

SUMMARY OF THE INVENTION The present invention addresses the above-described situation, and provides an intake device in which the intake passage is sufficiently long so that a dynamic effect of intake can be obtained in a low engine rotation region while minimizing the size of the entire engine as much as possible. The task is to achieve it.

(Means for Solving the Problems) In order to solve the above problems, the present invention uses the following means.

That is, the invention according to claim 1 of the present application provides a plurality of independent intake passages each communicating with each cylinder of the engine body,
In an intake device for a multi-cylinder engine configured by a plurality of collecting portions in which these independent intake passages are collected for each non-adjacent one in the ignition order, and a plurality of upstream intake passages respectively extending upstream from these collecting portions, The plurality of collecting portions are arranged in a substantially horizontal direction, and the independent intake passage is formed in a curved shape so that a required space is provided between the collecting portion and the engine body. A branch portion is provided in the middle of the upstream intake passage, and each branch passage downstream of the branch portion is provided with an air column natural vibration of the intake passage from the branch portion to each cylinder and an engine speed on a low rotation side. And the plurality of branch passages are bent in a substantially U-shape from one end of the collecting portion in the engine axial direction, and are passed side by side in the space and the other end of the collecting portion. It is provided so that it may extend.

The invention according to claim 2 of the present application, in the configuration of the invention according to claim 1, is characterized in that the interval in the juxtaposition direction of the independent intake passages is set to be smaller on the collecting portion side than on the engine side. Features.

Further, the invention according to claim 3 of the present application is the above-described claim 2.
And a throttle body is disposed in the upstream intake passage located at the other end of the collecting portion.

(Operation) According to the above configuration, the branch passage downstream of the branch portion provided in the middle of the plurality of upstream intake passages forming the intake passage is
Each independent intake passage is bent in a substantially U-shape from one end side in the engine axis length direction, passes side by side in a space formed between the collecting portion and the engine body, and extends to the other end side of the collecting portion. Therefore, it is possible to make the length of the branch passage or the upstream intake passage sufficiently long without requiring a space outside the collecting portion. Therefore, while suppressing the size of the entire engine, the intake passage upstream of the collecting portion is made sufficiently long, and the air column natural vibration of the pressure wave in the intake passage is tuned to a low engine speed. The supercharging effect in the low rotation region is obtained.

According to the second aspect of the invention, the interval in the direction in which the engine body, the collecting portion, and the plurality of independent intake passages are arranged in the juxtaposition direction is set to be smaller on the collecting portion side than on the engine side. It is possible to reduce the dimension of the connected portion on the independent intake passage side in the engine axial length direction.

According to the third aspect of the present invention, the upstream intake passage located at one end of the collecting portion, that is, the end opposite to the end of the collecting portion to which the upstream intake passage is bent and connected in a U-shape. Since the throttle body is arranged at a portion extending substantially linearly on the side of the unit, the arrangement structure of the throttle body is compact and simple.

(Example) Hereinafter, an example of the present invention will be described.

FIG. 1 is a plan view showing the entire engine according to the first embodiment. An engine body A of an engine body 1 has an axial length direction extending in a vehicle body width direction (lateral direction on the paper).
Is located within. An exhaust turbocharger 2 is disposed on the front side of the engine main body 1, that is, on the front side of the vehicle (above the paper surface), and a turbine case 2a of the turbocharger 2 is provided.
An exhaust manifold 3 and an exhaust passage 4 provided with a catalyst device, a muffler, etc. (not shown) on the downstream side are connected to each other, so that exhaust gas discharged from each cylinder of the engine body 1 is supercharged. After the turbine of the machine 2 is driven, it is discharged.

On the other hand, an intake device 10 for supplying intake air to each cylinder of the engine body 1 has an air cleaner 11 and an air flow meter at its upstream end.
12 is provided, and the downstream end is a blower case of the supercharger 2.
The first connection passage 13 is connected to the blower case 2b of the turbocharger, and the second connection passage 15 connects the air inlet 14a of the intercooler 14 disposed at the front of the engine room A.
An upstream intake passage 16 having an upstream end connected to an air outlet 14b of the intercooler 14, extending from one side of the engine room A to the rear of the engine main body 1 through one side,
The upstream intake passage, which is arranged on the rear side of the engine body 1
A collecting part 17 to which the downstream end of the connecting part 16 is connected;
A number of cylinders communicating the respective cylinders of the engine body 1 (in this example 4) is composed of a same number of independent intake passage 18 _{1-18 4.}

The collecting portion 17, the longitudinal direction is constituted by a vessel-shaped box which is disposed parallel to the axial direction of the engine body 1, and each independent passages 18 _{1-18 4} above, the second and third drawing As shown in the drawing, the common flange 18a connected to the rear side surface 1a of the engine body 1 extends horizontally and then curves upward, and the upper end common flange 18b is connected to the bottom surface 17a of the collecting portion 17. As a result, a space B is formed between the rear side surface 1a of the engine body 1 and the collecting portion 17. A flange 16a provided at the downstream end of the upstream intake passage 16 is connected to an end face 17b on one side (the right side in FIGS. 1 and 2) of the collecting portion 17 in the engine axial direction,
The space B is bent substantially U-shaped forward from this connection portion.
And passes through the space B toward the other side (same side, left side) in the engine axial direction and extends to the upstream side.

Also, as shown in FIG.
Engine body 1 with partition wall 17c in the engine axial direction
1st room 17 ₁ close to the engine and 2nd room far from the engine body 1
The two chambers 17 ₁ and 17 ₂ are arranged in a substantially horizontal direction and are divided into a common room 17 _2. The upstream intake passage 16 is connected to a first branch passage 16 b at a branch portion 16 b at the front of the engine room. ₁ and 2
It is branched into a branch passage 16 _2. The branch passages 16 ₁ and 16 ₂ pass through the space B as described above, and the downstream end thereof is connected to the end face 17b of the collecting portion 17 via the flange 16a. 16 ₁ and First Room 1
7 _1, the second branch passage 16 ₂ and ₂ second collection chamber 17 is communicated with each. In this case, as shown in FIG. 3, first, although the second branch passage 16 _1, 16 ₂ are arranged substantially horizontally in connection to the end face 17b of the collecting portion 17 at the downstream end, the while inclined upward slightly the first branch passage 16 ₁ from the connecting portion, the second branch passage 16 ₂ is bent slightly each with inclined downward U-shape, arranged vertically in the portion that passes through the space B Have been.

Then, among the independent intake passages 18 ₁ to 18 ₄ , the first and fourth cylinders connected to the first and fourth cylinders whose ignition order (first cylinder → third cylinder → fourth cylinder → second cylinder) are not adjacent. The fourth independent intake passages 18 ₁ and 18 ₄ are connected to the first collective chamber 17 _{1 to} the first branch passage 16.
_1, likewise the second ignition sequence is not adjacent, second, third independent intake passage 18 _2, 18 ₃ second collecting portion communicating with the third cylinder
17 _{2 to} the second branch passage 16 ₂ .

Here, the first and second collecting portions 17 ₁ , 17 2 are provided at the end of the collecting portion 17 opposite to the end face 17 b to which the upstream intake passage 16 (first and second branch passages 16 ₁ , 16 ₂ ) is connected. 17 ₂ with the communication passage 17d for communicating is provided, on-off valve 19 to the communication passage 17d is opened or shut off is provided. Also,
A throttle body 20 including a pair of throttle valves for controlling a passage area in the _first and second branch passages 16 ₁ and 16 ₂ is disposed in a portion of the upstream intake passage 16 that escapes upstream from the space B. ing. Furthermore, as shown in FIG. 3, the fuel injection nozzle 21 ... 21 in the downstream portion of each independent intake passage 18 _{1-18 4} are respectively installed, the upper portion of the nozzles 21 ... 21, these It is connected to a distribution pipe 22 that supplies fuel. In FIG. 1, reference numerals C and C denote storage sections of a suspension device called a suspension tower provided on the vehicle body on both sides of the engine room A.

 Next, the operation of this embodiment will be described.

When the turbine of the exhaust turbocharger 2 is driven by the exhaust gas discharged from each cylinder during operation of the engine, the intake air sucked from the air cleaner 11 is pressurized by the blower 2 of the supercharger 2 and After being cooled by the itancooler 14, it flows into the upstream intake passage 16. Then, the intake air flows into a branch portion 16 of the upstream intake passage 16.
b branches into the first and second branch passages 16 ₁ and 16 ₂ , and the first and second collective chambers 17 of the collecting portion 17 are divided by these branch passages 16 ₁ and 16 ₂ through the throttle valve in the throttle body 20. ₁ , 17 ₂
With flowing respectively, further intake air flowing into the first collection chamber 17 _1, the first, fourth independent intake passage 18 _1, 18 ₄ by the first, flows into the fourth cylinder, and the second collecting chamber 17 ₂ the second inlet, a third independent intake passage 18 _2, 18 ₃ by the second, the third cylinder, introduced during each intake stroke.

In this case, in the high engine rotation region, a large amount of intake air is supplied by the supercharging action of the supercharger 2, a large output torque is obtained, and the supercharging action of the supercharger 2 is not sufficiently obtained. In the low rotation region, the amount of intake air is increased due to the inertial supercharging effect of the intake air. That is, the negative pressure wave generated in the intake port when the intake valve is opened at the start of the intake stroke in each cylinder is generated by the independent intake passages 18 ₁ to 18 ₄ ,
After propagating upstream through the branch passages 16 ₁ and 16 ₂ of the collecting portion 17 and the upstream intake passage 16, the positive pressure wave is inverted at the branch portion 16 b of the upstream intake passage 16 and propagates through the passages downstream. This reaches the intake port just before the intake valve closes at the end of the intake stroke, and pushes intake air into the combustion chamber. At this time, if the second cylinder is described as an example, a negative pressure wave generated at the intake port of the second cylinder and inverted to a positive pressure wave at the branch portion 16b will be generated by the fourth cylinder in which the ignition sequence precedes. By combining positive pressure waves generated in the latter half of the intake stroke, the pressure waves become stronger positive pressure waves, and the amount of intake air charged to the second cylinder is further increased.

In this case, since the length from the intake port to the pressure wave inversion portion (branch portion 16b) is sufficiently long, the propagation period of the pressure wave and the intake The opening and closing timing of the valve is synchronized. As a result, the intake charge at the time of low engine rotation is increased, and the low-speed torque is increased. Here, the length from the intake port (intake valve) to the branch portion 16b is a value at which the supercharging pressure by the supercharger 2 is sufficient, that is, a wastegate valve (not shown) for bypassing exhaust gas to the turbine. Is set to tune near or below the engine speed (intercept point) at which the set supercharging pressure is reached.

When the engine rotates at a high speed, the on-off valve 19 in the collecting part 17 is opened and the first and second collecting parts 1 and 2 are connected by the communication passage 17d.
The communication between 7 ₁ and 17 ₂ allows the communication portion to be a reverse portion of the pressure wave, so that the above-described inertia supercharging effect is obtained even at high engine speeds, and the high-speed torque is further increased. become. Also, the first branch passage 16 ₁ in the first collection chamber 17 ₁ and the upstream intake passage 16 in the collecting portion 17 first, fourth
The second collecting chamber 17 ₂ in the collecting section 17 is shared by the cylinders.
And second branches in the upstream intake passage 16 passage 16 ₂ to the second,
Although shared by the third cylinder, the first, fourth, and second,
Since the ignition orders of the third cylinders are not adjacent to each other, there is no pressure wave interference between these cylinders, and the third cylinders act so as to reinforce the pressure waves as described above. This will be effectively demonstrated for each cylinder.

As described above, by increasing the length of the intake passage, the amount of intake air or the output torque is increased by the inertia supercharging effect in the low rotation region where the supercharging effect of the exhaust turbocharger 2 is not sufficiently obtained. However, according to the above configuration, when making the intake passage longer, the upstream air supply passage 16
The first and second branch passages 16 ₁ and 16 ₂ are bent into a substantially U-shape from one end of the collecting portion 17 in the engine axial direction, and the collecting portion 17 is bent.
Is provided so as to pass through the space B provided between the engine body 1 and the other end of the engine in the axial direction of the engine. As described above, the entire engine is not significantly increased in size, and a compact and sufficiently long intake passage can be obtained.

Further, according to the above configuration, the first constituting the collecting portion 17, and parallel second collecting chamber 17 _1, 17 ₂ substantially in horizontal direction, connecting the independent intake passage 18 _{1-18 4} on its bottom surface As a result, a required space B is provided between the collecting portion 17 and the engine body 1, but the upstream intake passage 16 passing through the space B is provided.
Since the first and second branch passages 16 ₁ and 16 ₂ pass vertically along the space B, the width of the space B (the dimension W in FIG. 1) can be relatively narrowed. it can. Therefore, the entire width of the engine, in particular, the amount of projection of the engine from the rear of the engine body 1 is suppressed.

Furthermore, according to this embodiment, as shown in the first and second figure, so that the distance between the arrangement direction of each independent intake passage 18 _{1-18 4} is wide in the engine body 1 becomes smaller in the collecting portion 17 side is set to, is the engine shaft length direction dimension of the collecting portion 17 of these independent intake passage 18 _{1-18 4} is connected is short.

Further, the upper air intake passage 16 passes through the space B from one end side of the collecting portion 17 toward the other end side and is bent in a U-shape to be connected to the other end side of the collecting portion 17. A throttle body is provided at one end of the collecting portion 17, that is, at a portion extending substantially linearly.
Since the throttle body 20 is disposed, the throttle body 20 is disposed in a compact and simple configuration.

Next, a second embodiment of the present invention shown in FIGS. 4 and 5 will be described.

In this embodiment, instead of the box-shaped collecting portion 17 formed as a separate body in the embodiment, the first constituting the upstream intake passage 46, the downstream end portion of the second branch passage 46 _1, 46 ₂ is the 1, the second gathering portions 47 ₁ and 47 _2, and the first gathering portion 47 ₁
First on the lower surface of the fourth independent intake passage 48 _1, 48 _4, and the second
The second, third independent intake passage 48 _2, 48 ₃ are connected to the lower surface of the collecting portion 47 _2. Further, in this embodiment, the intercooler 44 is disposed on the side of the engine room A, and accordingly, the air inlet 44a of the intercooler 44 and the front side of the engine body 31, that is, the front side of the vehicle (fourth side) A second connection passage 45 connecting the blower case 32b of the exhaust turbocharger 32 disposed above the drawing (above in the drawing) and an upstream portion of an upstream intake passage 46 connected to the air outlet 44b of the intercooler 44. Is different from that of the above-described embodiment.

Except for these points, the configuration of this embodiment is substantially the same as that of the above-described embodiment.
Each of the independent intake passages 48 _{1 for} communicating with the second collecting portions 47 ₁ and 47 ₂
48 ₄ together are a space B is provided between the curved shape is formed the collecting portion 47 _1, 47 ₂ and the engine body 31, the first, second branch passage 46 _1, 46 ₂ is the 1, the second assembly part 47 ₁ , 4
7 ₂ is bent in a substantially U-shaped forward extending on the upstream side in the space B. The first, the second collecting portion 47 _1, 47 ₂ is substantially parallel to the horizontal direction, first, second branch passage 46
_1, 46 ₂ is passing alongside up and down in the air B.

Therefore, also in this embodiment, similarly to the above-described embodiment, the length of the intake passage is sufficiently long, and the inertia supercharging effect is obtained in a low rotation region where the supercharging effect of the exhaust turbocharger 32 is not sufficiently obtained. As a result, the amount of intake air is increased, and the intake passage or the entire engine is made compact. Incidentally, in FIG. 4, 41 denotes an air cleaner, 42 the air flow meter, the first 49, second set 47 _1, 47 ₂ off valve provided in the communication passage 47d that communicates, 50 upstream intake passage 4
First provided on the 6, a throttle body with a built-in pair of throttle valve for controlling the second passage area of the branch passage 46 _1, 46 _2. Reference numeral 51 denotes a radiator disposed in front of the engine room A. Reference numeral C in FIG. 4 denotes a suspension tower (only one is shown) provided on the vehicle body on both sides of the engine room A. Reference symbol D in the drawing indicates a hood covering the upper part of the engine room A, respectively.

(Effects of the Invention) As described above, according to the present invention, a plurality of independent intake passages each communicating with each cylinder of the engine body, and a plurality of sets in which these independent intake passages are arranged for each non-adjacent ignition order And a plurality of upstream intake passages extending upstream from each of these gathering portions, in a multi-cylinder engine intake device, a branch portion downstream provided in the middle of the plurality of upstream intake passages constituting the intake passage Are bent in a substantially U-shape from one end side of each independent intake passage in the engine axial direction, and are passed side by side in a space formed between the collecting portion and the engine body. , The intake passage can be made sufficiently long while the intake passage is made compact. As a result, the natural vibration of the air column of the pressure wave in the intake passage is tuned to the low engine speed without causing a significant increase in the size of the entire engine. Will be improved.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present invention. FIG. 1 is a partially broken plan view of the first embodiment, FIG. FIG. 2 is a view taken in the direction of the arrow II in FIG. 2, FIG. 4 is an overall plan view of the second embodiment, and FIG. 5 is a side view taken in the direction of the arrow V in FIG. 1,31… Engine body, 16,46… Upstream intake passage, 16 ₁ , 46 ₁
... First branch passage, 16 ₂ , 46 ₂ ... Second branch passage, 16b ... Branch portion, 17,47 ₁ , 47 ₂ ... Collecting portion, 18 ₁ to 18 ₄ , 48 _{1 to} 48 ₄ ... Independent intake passage, 20 ... Throttle body, B ... Space.

Continuation of front page (72) Inventor Hisayuki Yamane 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. (56) References JP-A-63-100269 (JP, A)

Claims (3)

(57) [Claims] 1. A plurality of independent intake passages each communicating with each cylinder of an engine body, a plurality of gathering portions in which these independent intake passages gather for each non-adjacent ignition order, and an upstream portion from each of these gathering portions. A plurality of upstream intake passages extending to the side, the intake device of a multi-cylinder engine, wherein the plurality of gathering parts are arranged in a substantially horizontal direction, required between the gathering part and the engine body While the independent intake passage is formed in a curved shape so that a space is provided, a branch portion is provided in the middle of the upstream intake passage, and each branch passage downstream of the branch portion is provided from the branch portion. The air column natural vibration of the intake passage to each cylinder is provided so as to synchronize with the engine speed on the low rotation side, and the plurality of branch passages are substantially U-shaped from one end of the collecting portion in the engine axial direction.
An intake device for a multi-cylinder engine, wherein the intake device is provided so as to be bent in a letter shape and to pass through the space side by side and extend to the other end side of the collecting portion. 2. The space between the independent intake passages in the juxtaposition direction is set to be narrower on the collecting portion side than on the engine side, and the branch passage extends from one end side of the collecting portion in the engine axial length direction into the space. 2. The intake device for a multi-cylinder engine according to claim 1, wherein the intake device is bent substantially in a U-shape and connected to the other end of the collecting portion. 3. The intake device for a multi-cylinder engine according to claim 2, wherein a throttle body is disposed in an upstream intake passage located at the other end of the collecting portion.