JPS60216029A - Suction apparatus for engine - Google Patents

Abstract

PURPOSE:To reduce the suction resistance by rotatably installing a surge tank around the axis line in the longitudinal direction and connecting the opening of the tank wth a suction pipe on the periphery of the tank and forming the section of the suction pipe into circular form, thus obtaining the intake inertial effect within a wide engine operation range. CONSTITUTION:The intake air introduced into a surge tank 3 through a throttle valve 6 from an air filter is inhaled into a cylinder through a suction port from an annular suction pipe 13 installed onto the periphery of the tank from a communication hole 23 formed on the outer wall of the tank. 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 through a gear 26 at the edge part, and the inertial supercharging in a wide engine operation range is carried-out by varying the effective length of a suction passage by varying the position of a communication port 23 for the suction passage 13. The suction resistance can be reduced by forming the section of the suction passage formed onto the outer periphery of the tank 3 into circular form.

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 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.

(Object of the Invention) The present invention provides an intake system for a multi-cylinder engine with a lightweight and compact structure, which solves the above-mentioned problems regarding the intake system in which the state of the intake passage is variable according to the operating state of the engine. It is something to do.

(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 tank, a communication port formed on the right side and a part of the outer circumferential wall of the surge tank for communicating the 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 passage of the intake passage extension into the internal space of the surge tank is variable, characterized in that the cross-sectional shape of the intake passage extension is approximately circular. be.

(Effects of the Invention) Intake bag 1 for a multi-cylinder engine of the present invention having the configuration described above
According to the invention, an intake passage extension is provided around a surge tank that is rotatably provided around a longitudinal axis, and a communication port is formed in a part of the outer peripheral wall of the surge tank. Since the length of the intake passage is adjusted according to the rotation angle position, 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, saving space for installation in the vehicle. can be made smaller.

Furthermore, since the cross-sectional shape of the intake passage extension is approximately circular, intake resistance can be reduced and volumetric efficiency can be effectively improved.

(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 sectional view of this intake system taken along line -H in FIG. It is a sectional view along -H.

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.

This casing is split into an upper half and a lower half. 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 1 of each cylinder lO.
1, thereby forming an intake system from the air cleaner 4 to each cylinder 10 via the inside of the surge tank 3. The casing 7 and each branch pipe 8 are
As shown in FIG. 2.3, the integral body is fixed to one side of the cylinder head 9, so that each branch pipe 8 and each intake port 11 are connected, and the casing 7 A substantially linear intake passage 1 extending from to each cylinder 10
2 are formed independently. Also, casing 7
Extended portions 13 of each of the intake passages 12 are provided on the peripheral wall portion of the intake passage 12 . The extension portions 13 are provided independently, and are linearly connected to the upstream ends of the intake passages 12 in the upper portion of the casing 7, as shown in FIG. Then, from the connecting part A, it spirals downward along the vertical surface, that is, from the upper part of the casing 7 through the outer part, and then goes around the lower part, and then from the inner side to the central 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 I8 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.
A shaft portion 25 integral with the surge tank 3 protruding from 1 to the outside.
It is composed of a human-powered gear 26 fixed to the human-powered gear 26, an arc-shaped gear 27 meshed with the human-powered gear 26, and a diaphragm device 29 that drives this arc-shaped gear 27 via a lever 28. Engine l exhaust passage (
Exhaust pressure is introduced from (not shown). Here, since the exhaust pressure is high when the engine rotates at high speeds and becomes low when the engine speeds are low, the arcuate gear 27 and the input gear 26 rotate from the positions shown in the figure in the direction a as the engine speed increases. Accordingly, surge tank 3 is also
Rotates in direction a (not shown).

In addition, in this embodiment, as shown in FIG. are communicated through a communication port 31. This space 3o is used for extracting stable intake negative pressure for various control purposes. Further, as shown in FIG. 3, a fuel injection nozzle 32 is installed above each branch pipe 8, and 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 connected to each other with the side cover 21 removed.
It is constructed so that it can be easily assembled by inserting it into the main body.

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 8a in the branch pipe 8 and reaches the intake port 11 of each cylinder 10, where air is supplied.

When air is introduced into each cylinder 10 in this way, a negative pressure wave is generated, and this negative pressure wave passes through the air supply passage to the surge tank 3.
The air is propagated to the air, where it is reflected and its phase is reversed to become a positive pressure wave.This positive pressure wave brings about an intake inertia effect during the next intake stroke, thereby 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.

The cross-sectional shape of the intake passage extension 13 can be various shapes such as rectangular, square, and circular. However, in the case of a rectangular or square shape, the intake resistance is lower than in the case of a circular shape, so the present invention In this case, a circular cross section is adopted. Therefore, a groove 3a is formed on the outer peripheral surface of the surge tank 3 and has a semicircular cross-sectional shape that is open outward, and a groove 3a that is open outward and has a semicircular cross section is formed on the inner peripheral surface of the casing 7 at a position corresponding to the groove 3a. A groove portion 7a having a semicircular cross-sectional shape that is open toward the front is formed, and by aligning these groove portions 3a, the passage extension portion having a circular cross-section is formed.

Incidentally, in FIG. 2, the reference numeral 40 indicates a passage that functions as a blow-by gas passage, an EGR passage, and the like.

[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 line -H in FIG. 1, and FIG.
2 is a sectional view taken along line m--■ in FIG. 2, and FIG. 4 is a front view showing an example of a surge tank driving device. ■・・・Engine 2・・・Intake system 3・
... Surge tank 13 ... Intake passage extension part Fig. 1

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 position of the intake passage extension into the internal space of the siege tank is variable in accordance with a rotational angular position of the surge tank, wherein the cross-sectional shape of the intake passage extension is approximately the same. An engine intake device characterized by having a circular shape.