JPH057492Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an intake system for an engine that performs inertial supercharging, and particularly to its surge tank structure.

(Prior art and its problems) This type of engine intake system provides a surge tank in the middle of the intake passage, communicates the surge tank with each cylinder through independent intake passages of equal length, and connects the surge tank and the intake passage with each other. A resonance system is constructed that is matched to a predetermined operating range, and the intake pulsation is used to increase the filling efficiency through a dynamic effect.

By the way, as a surge tank structure in a conventional intake device, there is, for example, one shown in Japanese Utility Model Application Publication No. 120071/1983 (see FIG. 5). That is, the surge tank 1 has a cylindrical shape having an air inlet 2 at one end, and each intake passage 3 is connected to the side thereof. However, in this surge tank 1, the cross-sectional area in the longitudinal direction is uniform, and the connection positions of the intake passages 3 are at the same height along the longitudinal direction. In such a structure, in order to equalize the length of the intake passage 3, it is necessary to have at least the same length as the length of the cylinder row, and also to align the center of the surge tank 1 with the center of the engine in the cylinder row direction. This creates constraints on the layout around the engine. Further, the amount of air flowing into the intake passage 3 decreases from the side of the air inlet 2 toward the other end, causing variations in the amount of air taken into each cylinder.

(Purpose of the invention) In view of the above-mentioned circumstances, the present invention is equipped with a surge tank that has a structure that allows greater freedom in the layout around the engine and equalizes the amount of air flowing into each intake passage. Its purpose is to provide an intake system for engines.

(Structure of the invention) For this reason, the engine intake system according to the invention is
A surge tank has an air inlet at one end in the longitudinal direction along the engine crankshaft, and is formed so that the cross-sectional area decreases from the one end to the opposite end. , an offset arrangement means for arranging the surge tank such that its center position in the longitudinal axis direction is offset from the center position in the crankshaft direction of the engine toward the one end side along the longitudinal axis direction; and a plurality of independent intake passages connecting the surge tank and the plurality of intake ports of the engine, each independent intake passage being connected to a side surface of the surge tank opposite to the side on which the engine is disposed. The upper intake passage is integrally attached to the upper part, and is connected to the lower part of the upper intake passage, and is formed to extend smoothly, and the lower end is connected to the corresponding intake port of the engine from the side. The extension axis of each independent intake passage at the attachment portion to the surge tank is set to be inclined with respect to the longitudinal axis of the surge tank, and each independent intake passage The attachment position of the surge tank to the surge tank is set so that the other end is lower than the one end.

With the above configuration, a large space can be created on the anti-offset side of the surge tank, and the space around the engine can be used effectively, and the air flow speed increases from the air inlet side to the other end of the surge tank. This makes it possible to equalize the amount of air flowing into each intake pipe.

(Embodiment of the invention) The first and second illustrated surge tanks 11 are formed in a shape whose cross-sectional area decreases from the side of the air inlet 12 provided at one end toward the other end. In addition, each intake passage 13 connects the surge tank 11 and each intake port 21 to 24 of the engine body 20, which will be described later.
Each intake passage section 13A-1 forming a part of ~16
6A is integrally formed from the end on the side of the air inlet 12 to the other end.

Each of the intake passages 13A to 16A is formed so that the height of its opening position varies along the longitudinal direction of the surge tank 11, and the height gradually decreases from the air introduction port 12 side. Further, the mounting flange portions 17 of each of the intake passage portions 13A to 16A, which are curved downward, are formed on the same surface, and therefore,
The length of each of the intake passages 13A to 16A is gradually shortened from the intake passage portion 13A to the intake passage 16A. Further, the axial direction of each of the intake passages 13A to 16A is arranged obliquely with respect to the air inflow direction of the surge tank 11, so that air flows smoothly into the surge tank 11.

On the other hand, the surge tank 1
1 and each intake port 21 to 24 of the engine body 20
The other intake passage sections 13B to 16B constituting each of the intake passages 13 to 16 connecting between the A mounting flange portion 18 for connection with 13A to 16A is formed, and a mounting flange portion 19 to the side surface of the engine body 20 is formed at the other end. Further, the length of each intake passage portion 13B to 16B is the same as that of each intake passage portion 13A on the surge tank 11 side.
~ Each intake passage 13 to 16 when connected to 16A
are set to have the same length.

Figure 4 shows each intake passage section 1 on the surge tank 11 side.
3A to 16A and each intake passage portion 13B to 16B attached to the engine main body 20 are shown assembled, and 25 is a volume chamber formed at the time of assembly;
Each control valve 26 is connected to each intake passage 13 to 16 in the middle thereof.
They are able to communicate with each other via. The opening and closing of each of the control valves 26 is integrally controlled by a rotary shaft 28 provided through a shaft support 27 integrally formed on the side of the intake passages 13B to 16B.

When configured as described above, each of the intake passages 13 to 16
The length of the surge tank can be set equally.
3 with respect to the center of the engine in the direction of the cylinder row of the engine body 20, the space around the engine on the right side in FIG. 3 becomes larger, and can be effectively used as a space for installing other accessories. Also, since the cross-sectional area of the surge tank 11 is narrowed from the air inlet 12 side to the other side, the amount of air flowing into each of the intake passages 13-16 can be made approximately equal, and the amount of air flowing into the intake passages 13-16 can be made approximately equal.
Since the axial direction of the surge tank 16 is inclined with respect to the air inflow direction of the surge tank 11, the air can be smoothly introduced into the intake passages 13 to 16.

In this embodiment, by controlling the opening and closing of the control valve 26 according to the engine speed, the lengths of the intake passages 13 to 16 are substantially changed, and the intake air is controlled in the high and low speed regions of the engine, respectively. This creates a dynamic effect.

(Effect of the invention) As described above, according to the engine intake system according to the invention, the surge tank can be placed at a position offset from the engine while maintaining the length of each intake passage uniformly. Therefore, the space around the engine can be used effectively, and the effective space in the engine room can be expanded. Further, the amount of air flowing into each cylinder can be made uniform, and the intake air distribution property is also improved, thereby making it possible to eliminate variations in combustion among the cylinders.

[Brief explanation of the drawing]

Fig. 1 is a side view of the surge tank used in the intake system according to the present invention, Fig. 2 is a plan view thereof, Fig. 3 is a plan view of the intake passage on the engine body side, and Fig. 4 is a state in which it is assembled to the engine. FIG. 5 is a perspective view showing a conventional example. 11...Surge tank, 12...Air inlet,
13-16...Intake passage, 20...Engine body, 21-24...Intake port.

Claims (1)

[Claim for Utility Model Registration] An air inlet is provided at one end in the longitudinal direction of the engine along the crankshaft direction, and the cross-sectional area decreases from the one end to the opposite end. a surge tank formed as shown in FIG. and a plurality of independent intake passages connecting the surge tank and a plurality of intake ports of the engine, each independent intake passage being arranged by the engine of the surge tank. The upper intake passage side is integrally attached to the upper part of the side opposite to the side where the upper intake passage is attached, and the upper intake passage is connected to the lower part of the upper intake passage, and is formed to extend smoothly. and a lower intake passage connected to the corresponding intake port from the side, and the extension axis of each independent intake passage at the attachment site to the surge tank is inclined with respect to the longitudinal axis of the surge tank. An intake system for an engine, characterized in that the attachment position of each independent intake passage to the surge tank is set so that the other end is lower than the one end.