JPS60216028A - Suction apparatus for engine - Google Patents

Abstract

PURPOSE:To prevent the collection of water and oil in a suction passage by rotatably installing a surge tank around the axis line in the longitudinal direction and obtaining the intake inertial effect within the broad operation range of an engine by substantially varying the length of a suction pipe and forming drain holes in the extension lower part of the suction passage. CONSTITUTION:The intake air introduced into a surge tank 3 through a throttle valve 6 from an air filter passes through an annular suction passage 13 arranged on the periphery of the surge tank 3 from a communication port 2 formed on the outer wall of the tank and is introduced into a combustion chamber from a suction port. The both edges of the surge tank 3 are supported by bearings 19 and 22, and the tank 3 is turned according to the engine operation state by an exhaust-pressue sensitive diaphragm actuator, etc. through a gear 26 installed at the edge part, and the actual length of a suction pipe is varied by varying the position of the port 23. Drain holes 42 are formed in the extension lower part of the suction passage 13, and drainage is discharged outside by a communication passage 41 communicating to each drain hole 42.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an intake system for a multi-cylinder engine.

(Prior Art) In an engine, it is effective to utilize the so-called intake inertia effect in order to increase intake air filling efficiency and improve output. This intake inertia effect depends on the relationship between the length of the intake passage, the cross-sectional area of the passage, and the engine speed.
When the cross-sectional area of the passage is constant, the length of the intake passage at which this effect is most effectively achieved becomes shorter as the engine speed increases; (There is a relationship in which the size of the passage cross-sectional area that can be obtained increases as the engine speed increases.

Therefore, for example, Utility Model Application Publication No. 56-2023 and Utility Model Application Publication No. 5
As shown in Japanese Patent No. 7-22629, by providing a surge tank in the middle of the intake system and changing the state of the intake passage from the surge tank to each cylinder according to the operating state of the engine, it is possible to An intake system that can utilize the intake inertia effect in the engine operating range has been proposed.

However, all of the intake systems described in the above-mentioned published utility models have a structure in which the passage length is changed by simply sliding a movable tube fitted into a fixed tube in a linear direction, so that the passage length can be changed within the required engine operating range. In order to utilize this method, the change in the length of the intake passage must be significantly increased, which increases the size of the entire device and creates space problems when an engine incorporating the intake device is installed in an automobile. That will happen.

To solve this problem, for example, the engine's intake system should be equipped with a surge tank that is rotatable around the longitudinal axis, an intake passage branch connected to each cylinder of the engine, and an intake passage branch that is connected to each cylinder of the engine. an intake passage extension extending from an end of the surge tank and provided around the surge tank; and a communication line formed in a part of the outer peripheral wall of the surge tank and communicating the internal space of the surge tank with the intake passage extension. It is conceivable that the air intake passage may be provided with a port, and may be configured such that the position in which the intake passage extension portion communicates with the internal space of the surge tank is variable depending on the rotational angular position of the surge tank.

However, if the intake device is configured in this way,
There is a drawback that, for example, water, fuel, oil in blow-by gas, etc. accumulate in the intake passage extension provided around the surge tank.

(Object of the Invention) The present invention provides an engine intake system that solves the above-mentioned problems regarding intake systems in which the state of the intake passage is variable depending on the operating state of the engine.

(Structure of the Invention) The present invention provides a surge tank rotatably provided around a longitudinal axis, an intake passage branch connected to each cylinder of an engine, an intake passage branch extending from an end of the intake passage branch, and a surge tank rotatably provided around a longitudinal axis. an intake passage extension provided around the surge tank; and a communication port formed in a part of the outer peripheral wall of the surge tank for communicating an internal space of the surge tank with the intake passage extension; Depending on the rotation angle position of
An intake system for an engine in which the position of communication of the intake passage extension with the internal space of the surge tank is variable, characterized in that a drain hole is formed at a lower position of the intake passage extension. be.

(Effects of the Invention) According to the multi-cylinder engine intake system of the present invention having the configuration described above, the intake passage extension is provided around the surge tank rotatably provided around the longitudinal axis, and the surge A communication port is formed in a part of the outer peripheral wall of the tank,
Since the length of the intake passage is adjusted according to the rotational angle position of the surge tank, the size of the device does not increase due to the length adjustment of the intake passage, and the entire device can be configured compactly. The installation space can be reduced.

Further, since a drain hole is provided at the lower portion of the intake passage extension, water, fuel, oil in blow-by gas, etc. accumulated at the lower portion can be effectively drained.

(Embodiments) Hereinafter, an intake system for a multi-cylinder engine according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is an intake system for a multi-cylinder engine according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of this intake system taken along the line ■--■ in FIG. 1, and FIG. 3 is a cross-sectional view along the line It is a cross-sectional view along -■.

In FIGS. 1 and 2, reference numeral 1 indicates a four-cylinder engine, and an intake device 2 is incorporated into this engine 1. In FIG. This intake device 2 includes a cylindrical surge tank 3 shown in FIG. 2, into which air is introduced from an air cleaner 4 via an air flow meter 5 and a throttle valve 6. It looks like this.

Further, a cylindrical casing 7 is provided on the outer periphery of the surge tank 3 coaxially with the surge tank 3. Branch pipes 8 of the same number as the number of cylinders of the engine 1 are branched from the upper part of the casing 7, and the branch pipes 8 are fixed to the cylinder head 9 to form an intake port 11 of each cylinder IO.
This constitutes an intake system that extends from the air cleaner 4 through the surge tank 3 to each cylinder 10.

The casing 7 and each branch pipe 8 are integrally formed as shown in FIG. are connected to form substantially linear intake passages 12 extending from the casing 7 to each cylinder 10, respectively.

Furthermore, extensions 13 of each of the intake passages 12 are provided on the peripheral wall of the casing 7 . The extension portions 13 are provided independently by partition walls 14 erected on the inner surface of the casing 7, and as shown in FIG. connected in a straight line. Then, it spirals downward from the connection part along the vertical surface, that is, from the upper part of the casing 7 through the outer part, and then from the inner part to the center part of the casing 7. It is formed in the shape of

As shown in FIG. 2, the surge tank 3 has one end opened, and the internal space 16 communicates with the upstream part of the intake system where the throttle valve 6 is provided via the opening 17 and the artificial part 18 of the casing 7. and a bearing 19 at the end.
A side cover 21 is pivotally supported on the casing 7 via the
is rotatably supported within the casing 7 via a bearing 22. This surge tank 3 is provided with a plurality of communication ports 23 on its circumferential surface, and the internal space 16 and each of the extension portions 13 are communicated with each other through the communication ports 23.

Further, as shown in FIG. 4, a drive mechanism 24 for rotating the defining rotating member 15 is provided outside one end of the casing 7. The shaft part 2 is integrated with the surge tank 3 that protrudes from the
5, a circular arc gear 27 meshed with the human gear 26, and a diaphragm device 29 that is driven via a lever 28. Exhaust pressure is introduced from an exhaust passage (not shown) of the engine 1.

Here, since the exhaust pressure is high when the engine rotates at high speeds and becomes low when the engine speeds are low, as the engine speed increases, the arcuate gear 27 and the human power gear 26 rotate in the direction a from the positions shown in the figure, respectively. Along with this, the surge tank 3 also rotates in the direction a (not shown in FIG. 3).

Additionally, in this embodiment, as shown in FIG.
6 are communicated with each other through a communication port 31. this space 3
0 is used to extract stable intake negative pressure for various controls. Further, as shown in FIG. 3, a fuel injection nozzle 32 is installed above each branch pipe 8, and the fuel supplied through a fuel supply pipe 33 is injected into each intake passage 12 by the nozzle 32. ing. Furthermore, the casing 7 and the surge tank 3 are configured so that they can be easily assembled by inserting the surge tank 3 into the casing 7 with the side cover 21 removed.

According to the above configuration, the air sucked from the air cleaner 4 of the engine 1 is introduced into the surge tank 3 via the air 70, the meter 5 and the throttle valve 6, and is further introduced into the surge tank 3 through the communication line formed on the outer peripheral wall of the surge tank 3. It is distributed from the port 23 to each intake passage extension 13 . And each extension part 13
After passing through the air in a spiral manner, the air passes through the intake passage branch portion 8a in the branch pipe 8 and reaches the intake port 11 of each cylinder IO, where intake is performed.

As shown above, when air is introduced into each cylinder 10, a negative pressure wave is generated, and this negative pressure wave propagates through the intake passage to the surge tank 3, where it is reflected and the phase is reversed to become a positive pressure wave. , this positive pressure wave brings about an intake inertia effect during the next intake stroke, improving the filling effect.

Note that, as described above, since the substantial length of the extension portion 13 of the intake passage is changed by the exhaust pressure that changes depending on the engine speed, the intake inertia effect can always be obtained in a desired state.

However, in the case of the above-mentioned configuration of the intake passage, that is, when a part of the intake passage is wound around the surge tank and has a spiral shape, there is water in the lower part of the intake passage extension 13. There is a problem that fuel, oil in blow-by gas, etc. tend to accumulate.

Therefore, in one embodiment of the present invention, a reservoir 40 for storing the water etc. is provided at the lower position, and a reservoir 40 is provided at the lower position.
A drain hole 41 is formed in the second reservoir 40 to drain the water and the like. The water, fuel, etc. accumulated in the reservoir 40 may be directly discharged out of the device through the drain hole 41, but this drain hole 41 is connected downstream of the intake passage 12 by a passage 42 as shown in FIG. The water, fuel, etc. may be automatically supplied to the intake passage 12 by the negative pressure of the intake passage 12.

In the embodiments described above, a reservoir is provided in each of the intake passages, and a drain hole is formed in each reservoir. However, one reservoir is provided for each adjacent intake passage extension, and A drain hole may also be formed.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an intake system for a multi-cylinder engine according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1, and FIG.
A sectional view taken along the line ■--■ in FIG. 2, and FIG. 4 are a front view showing an example of a surge tank driving device. 1, ,0. Engine 2, Intake system 3, Surge tank 13, ', Intake passage extension 40, Reservoir 41. ,,, drain hole 42, . 9.
Aisle number 31! I Figure 4 “°.

Claims (1)

[Claims] A surge tank rotatably installed around the longitudinal axis, an intake passage branch connected to each cylinder of the engine,
An intake passage extension extending from the end of the intake passage branch and provided around the surge tank; Equipped with a communication port that communicates with the
An intake system for an engine in which a communication position of the intake passage extension part with the internal space of the surge tank is variable according to a rotational angular position of the surge tank, the intake passage including a drain hole at a lower position of the intake passage extension part. An engine intake system characterized by having a hole.