JPH0380965B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an intake system for an engine, and particularly to one in which the shape of an intake passage and the structure of an intake passage connecting portion are improved.

(Prior art) In general, in an engine, in order to effectively utilize the intake inertia effect to increase intake air filling efficiency and increase engine output, the intake passage is made as close to a straight line as possible and the intake passage is made as long as possible. It must be configured to provide a passageway.

However, the intake passage of an engine is generally formed in a curved shape that rises upwards due to constraints on the external dimensions of the engine when installed in the engine room.
If this intake passage were to stand up integrally and curved upward from the connection part with the engine body, it would be difficult to cast the intake passage, and the fuel would be installed diagonally near the connection part with the engine body. When drilling the nozzle mounting hole for the injection nozzle, the upper part of the intake manifold interferes with the drill, making it difficult to drill.For such reasons, it is necessary to divide the intake passage and connect it at the connecting flange. is normal.

For example, Japanese Utility Model Application Publication No. 59-175666 describes an intake manifold in which the intake manifold is divided downstream of the collective intake passage (surge tank) and connected with flanges, as shown in Fig. 6. The intake passage 102 is substantially the same as that in the above publication.

In addition, as shown in FIG. 7, a portion of the intake passage 102 that extends substantially horizontally from the connecting portion with the engine body is divided, and a flange portion 102A is oriented vertically.
Some devices are designed to connect by .

(Problems to be solved by the invention) The intake manifold and the sixth
As in the intake manifold shown in the figure, the intake passage 102
When the connecting flange portion 102A is provided at the reversed curved portion, the total width of the engine E increases by the width B of the connecting flange portion 102A protruding from the outside of the intake passage 102.

Furthermore, when the connecting surface of the connecting flange portion 102A is oriented vertically as in the intake passage 102 in FIG. There is a problem that durability is significantly reduced.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide an engine intake device having a connection part with excellent vibration resistance without causing an increase in the overall width of the engine. be.

(Means for Solving the Problems) An engine intake system according to the present invention is an engine intake system that supplies intake air through an intake passage connected to a side of an engine body. is divided into an upstream intake passage having a surge tank at its downstream end and a downstream intake passage downstream of the surge tank, and the downstream intake passage extends approximately horizontally from the side of the engine body and curves upward. The connecting surface of the connecting flange between the surge tank of the upstream intake passage and the downstream intake passage is approximately J-shaped with respect to the rolling direction around the rolling axis located near the crankshaft of the engine. The connecting flange is vertically formed in an inclined shape that becomes lower toward the engine body, and is configured such that the outer end of the connecting flange does not protrude further outward than the outer end of the downstream intake passage.

(Function) In the engine intake device according to the present invention,
As described above, since the downstream intake passage (the part corresponding to the intake manifold) is formed in a roughly J-shape that extends roughly horizontally from the side of the engine body and curves upward, the intake air passes through the horizontal part. At this time, intake inertia increases and charging efficiency increases.

A connecting flange is provided to connect the upstream end of the downstream intake passage that rises up in a curved shape and the surge tank of the upstream intake passage, and the connection surface is rotated around the rolling axis near the crankshaft of the engine. Since it is oriented substantially perpendicular to the direction, only the force acting on the seal of the connecting portion is mainly in the direction substantially perpendicular to the sealing surface.

In addition, since the outer end of the connecting flange is configured so that it does not protrude outward beyond the outer end of the downstream intake passage, the overall width of the engine can be increased due to the outward protrusion of the connecting flange. do not have.

(Effect of the invention) In the engine intake device according to the present invention,
As described above, the intake passage is divided into an upstream intake passage that has a surge tank at the downstream end and a downstream intake passage that is downstream of the surge tank, and the downstream intake passage is approximately horizontal from the side of the engine body. The connecting surface of the connecting flange that connects the downstream intake passage to the surge tank is approximately perpendicular to the rolling direction around the rolling axis near the engine crankshaft. Since it is formed in an inclined shape that becomes lower toward the main body side, even if the engine rolls, almost no force is applied to the sealing part of the connecting part in the direction parallel to the sealing surface, improving sealing performance and durability. and has excellent vibration resistance.

Furthermore, since the outer end of the connecting flange is configured so as not to protrude further outward than the outer end of the downstream intake passage, the overall width of the engine can be reduced because the connecting flange does not protrude outward.

(Example) Examples of the present invention are shown below in the drawings (Fig. 1 to 5).
The explanation will be based on Figure).

FIG. 1 is a plan view of a four-cylinder engine E, and FIG. 2 is a schematic front view of the same. The intake passage of this engine E includes an upstream intake passage 1 through which intake air for four cylinders flows; The upstream end of the upstream intake passage 1 is connected to an air cleaner, and an air flow meter, a throttle valve, etc. are installed in the middle of the air cleaner. is connected to surge tank 3.

The downstream intake passage 2 constitutes an intake manifold, and its upstream end is connected to the surge tank 3, and each of the four branched intake passages 2a is connected to a portion corresponding to each intake port on the side surface of the cylinder head 4. Connected.

A fuel injection nozzle 5 is installed obliquely from above above the downstream end of each of the branch intake passages 2a, and each of these four fuel injection nozzles 5 is located above the branch intake passage 2a and is connected to the surge tank 3. A fuel return pipe 7 connected to a pressurized fuel supply pipe 6 disposed in a space between the branch intake passage 2a and one end of the pressurized fuel supply pipe 6 is connected to the fuel injection nozzle 5 and branched from the fuel injection nozzle 5. It extends through the gap between the supply passages 2a.

Each branch passage 2a as the downstream intake passage 2
As shown in FIG. 2, the cylinder head 4 is formed in a substantially J-shape that extends outward for a predetermined length substantially horizontally from the side of the cylinder head 4 and further curves upward at a predetermined curvature in an arc shape. An integrated flange portion 2A for connecting to a connection portion of the surge tank 3 is provided at the upper end of the main branch intake passage 2a.

The flange portion 2A has four circular openings 8 connected to each branch intake passage 2a, and the connecting surface 9 of the flange portion 2A faces toward the engine body so as to be substantially perpendicular to the rolling direction of the engine E. The flange portion 2A is formed in a downwardly sloping shape and has a nozzle mounting hole 1 for the fuel injection nozzle 5.
It is located at a height that will not interfere with the drill when drilling the 0.

The connection surface 9 of the flange portion 2A is connected to the engine E.
"Substantially perpendicular to the rolling direction" means that point R in FIG. Assuming that the rolling axis is located, the rolling direction at the position of the connecting surface 9 is a circular arc C centered on the rolling axis R, and the connecting surface 9 is approximately perpendicular to the circular arc C.

Further, the flange portion 2A is connected to the branch intake passage 2.
As mentioned above, the outer end of the flange portion 2 protrudes outward from the outer end of the inverted portion 11 because the flange portion 2 is provided above the inverted portion 11 of A in an inclined shape that becomes lower toward the engine body side. There's nothing to do.

The flange portion 2A is connected to the connection portion on the lower side of the surge tank 3 via a gasket, and for this purpose a plurality of bolt holes 12 are provided at the peripheral edge of the flange portion 2A.

Among the bolt holes 12, a bolt hole 12 on the engine body side and located between the branch intake passage 2a and the branch intake passage 2a is provided.
is the flange portion 2A as shown in FIGS. 4 and 5.
It is formed in a wall portion 13 extending in a direction perpendicular to the connecting surface 9 from the lower side and formed in a rib shape between the branch intake passages 2a.
3 reinforces the connection between the flange portion 2A and the branched intake passage 2a.

In the above configuration, since the connecting surface 9 of the flange portion 2A is provided so as to be substantially perpendicular to the rolling direction, the rolling of the engine E causes the packing of the connecting portion to receive a force in a direction parallel to the sealing surface. Since no force acts on the sealing surface and only a force in a substantially perpendicular direction acts on the sealing surface, the seal does not become fatigued and the sealing function of the seal is maintained for a long period of time.

Since the downstream intake passage 2 is formed as a single piece without any connecting parts, it has little intake resistance and is also easy to manufacture and assemble.

As described above, since the flange portion 2A does not protrude from the outside of the inverted portion 11 of the branched intake passage 2a, the overall width of the engine E does not increase.

The rib-shaped wall portion 13 of the bolt hole 12 of the flange portion 2A strongly reinforces the connection structure between the flange portion 2A and the branched intake passage 2a.

Since the flange portion 2A is inclined downwardly toward the engine body, there is no interference between the flange portion 2A and the drill when drilling the nozzle mounting hole 10.

Since it is provided in the space between the fuel return pipe 7, the fuel injection nozzle 5, and the intake manifold 2, the fuel return pipe 7 is sufficiently protected against external shocks.

The intake system of the present invention can be applied not only to four-cylinder engines but also to other multi-cylinder engines, as well as single-cylinder engines, and of course can also be applied to intake systems for diesel engines. .

[Brief explanation of drawings]

Among the drawings, FIGS. 1 to 5 show embodiments of the present invention. FIG. 1 is a plan view of the engine, FIG. 2 is a front view thereof, FIG. 3 is a plan view of the intake manifold, and FIG. 4 is a plan view of the engine. 5 is a front view of a surge tank and an intake manifold, FIG. 5 is a sectional view taken along the line of FIG. 4, and FIGS. 6 and 7 are front views of an engine according to the prior art. E...Engine, 1...Upstream intake passage, 2...
...Downstream intake passage, 2a...Branch intake passage, 2A
... Connection flange section, 3 ... Surge tank, 9 ...
...connection surface.

Claims (1)

[Scope of Claims] 1. An intake system for an engine configured to supply intake air through an intake passage connected to a side of an engine body, wherein the intake passage has a surge tank at its downstream end. and a downstream intake passage on the downstream side of the surge tank. The connecting surface of the connecting flange between the surge tank of the passage and the downstream intake passage is approximately perpendicular to the rolling direction around the rolling axis located near the engine crankshaft, and is sloped downward toward the engine body. An intake device for an engine, characterized in that the outer end of the connecting flange portion does not protrude further outward than the outer end of the downstream intake passage.