JP6936191B2 - Engine intake system - Google Patents

Description

The present invention relates to an intake device provided with an improved intake manifold in an industrial diesel engine or an automobile engine.

As disclosed in Patent Document 1, for example, the intake manifold of an engine generally has a structure in which one passage on the air supply side branches into each cylinder (each intake port).

In industrial engines, such as small diesel engines for developing countries and low-priced models, one large intake outlet that covers each intake port without separating each cylinder for cost and space savings. A box-shaped (box-shaped) intake manifold having an opening) is also frequently used (see Patent Document 2).

Japanese Unexamined Patent Publication No. 2007-321641 Japanese Unexamined Patent Publication No. 2001-329923

In the box-shaped intake manifold, the intake pipe is not branched for each intake port, so the intake amount is less than the expected amount due to the influence of the pulsating group that flows back from other intake ports, and combustion occurs. The condition worsens, and the diesel engine has the inconvenience of increasing black smoke and PM.

Therefore, it was considered to take a sufficient volume of the box-shaped intake manifold so that the intake manifold itself also serves as a surge tank common to each cylinder to reduce intake interference and increase the intake amount. When the amount of intake is increased, not only the output can be improved, but also the exhaust gas such as PM can be reduced, which has the advantage of being able to respond to the tightening of exhaust gas regulations.

However, in a small diesel engine, there is an injection pump near the intake port at the end of a plurality of cylinders, and the space around the intake port is limited due to the arrangement of the fuel injection pipe. Therefore, the shape of the box-shaped intake manifold must be adapted to the restricted space, and therefore there is a problem that it is difficult to obtain a sufficient volume.

An object of the present invention is to improve the intake efficiency of each cylinder without increasing the volume and to strengthen the exhaust gas regulation by further structurally devising a box-shaped intake manifold in which it is difficult to secure a sufficient volume. The point is to provide an intake device for the engine that can be handled.

The present invention relates to an engine intake device.
A manifold main body having an opening corresponding to an intake port and an intake manifold having an air intake are provided.
The opening is set to one opening formed so as to cover all of the plurality of intake ports.
Inside the side wall near the opening in the manifold body, a guide is provided to guide air toward the opening to the center in the width direction of the opening .
The guide is characterized in that it is formed over the entire width of the opening in the direction of arranging the intake ports.

For example, guides are provided on each of a pair of wide outlet walls along the intake port alignment direction to form one opening, and the downstream end of the guide in the air flow direction is the opening of the manifold body. It is closer to the upstream side in the air flow direction than the end face.

According to the present invention, the guide action of the guide allows air to smoothly enter the intake port, and when the air crosses the guide, turbulent energy that is not attenuated in the "small inertial region" is generated, and the fuel is generated. Combustion is activated by promoting mixing with air.
In addition, the pulsating group flowing back toward the intake manifold along the inner peripheral surface of the intake port is received by the end surface of the guide on the intake port side, and the backflow to the intake manifold can be expected to be suppressed.

As a result, while adopting a box-shaped intake manifold that makes it difficult to secure a sufficient volume, it is possible to improve the intake efficiency of each cylinder without increasing the volume and respond to the tightening of exhaust gas regulations by further structural ingenuity. Can provide an intake system for an engine.

Longitudinal sectional view of a main part showing an intake device of an engine according to the present invention. The intake manifold for two cylinders is shown, (A) is a plan view, and (B) is a side view seen from the opening side. Schematic side view of the engine to which the intake manifold shown in FIGS. 1 and 2 can be applied. Top view showing the main part of the engine shown in FIG. An intake device according to another embodiment is shown. FIG.

Hereinafter, embodiments of the engine intake device according to the present invention will be described with reference to the drawings in the case of an industrial vertical in-line 2-cylinder diesel engine.

First, an outline of an industrial vertical in-line 2-cylinder diesel engine (hereinafter, simply abbreviated as an engine) E to which an engine intake device (hereinafter, simply abbreviated as an intake device) according to the present invention can be assembled. explain.

As shown in FIGS. 3 and 4, in the engine E, the cylinder head 12 is assembled on the cylinder block 11, the cylinder head cover 13 is assembled on the cylinder head 12, and the timing transmission case is in front of the cylinder block 11. 14 is assembled, and the engine cooling fan 15 is arranged in front of the timed transmission case 14. A flywheel 16 is arranged after the cylinder block 11, and an oil pan 17 is assembled under the cylinder block 11.

An intake manifold 18 is assembled on one lateral side of the cylinder head 12, and an exhaust manifold 19 is assembled on the other lateral side. A pump accommodating case 20 is arranged on the intake side of the cylinder block 11, and a fuel injection pump 23 is inserted therein from above. A pair of front and rear fuel injection nozzles 21 and 22 are attached to the cylinder head 12. A pair of front and rear fuel injection nozzles 21 and 22 are connected to the tip of a fuel injection pipe which is a pair of pipe materials 1 and 2 derived from the fuel injection pump 23.

In FIGS. 3 and 4, 1a and 2a are parallel portions of the pipe members 1 and 2, respectively, and 3 is a clamp that restrains the parallel portions 1a and 2a to each other. Further, the engine E shown in FIGS. 3 and 4 is drawn as an intake manifold 18 assembled with a conventional structure. An improved version of the conventional intake manifold 18 is the intake device A according to the present invention described below.

[Embodiment 1]
As shown in FIGS. 1 and 2, the intake device A of the engine is right at a position biased toward the rear side of the manifold main body 4A bolted to the right side surface 12a of the cylinder head 12 and the manifold main body 4A. It has an intake manifold 4 with a suction portion 4B protruding toward it. The manifold body 4A is provided with an opening 5 sized to cover the two intake ports p of the cylinder head 12, and the suction portion 4B is tubular and has one suction port 4b. That is, the intake manifold 4 is configured in a so-called box shape.

The shape of the opening 5 is formed in a substantially oval rectangle (substantially oval) long in the front-rear direction (horizontal direction) covering the first and second intake ports p1 and p2 arranged in the front-rear direction. The intake port p on the front side of the engine E is referred to as the first intake port p1, and the rear side is referred to as the second intake port p2. The inside of the manifold main body 4A is formed in a suction passage 4W, which is one internal space for communicating one suction portion 4B and the opening 5.

As shown in FIGS. 2A and 2B, both the suction port 4b and the opening 5 are holes facing in the horizontal direction. Therefore, a part of the air sucked from the suction port 4b flows through the suction path 4W as shown by the arrow a toward the second intake port p2, and a part of the air flows forward through the suction path 4W and then the arrow b. It is considered that the air flows toward the first intake port p1. The structure may be such that the suction port 4b faces upward.

As shown in FIG. 2, the suction portion 4B is set in a biased state in which the right end (rear end as a part) of the suction portion 4B is slightly behind the rear end of the opening 5 of the manifold main body portion 4A. is not it. Note that 6 in FIG. 2B is small holes for bolting formed at three locations in the manifold main body 4A, and 7 is a return pipe for returning the fluid to the intake manifold 4 which is an intake system path. (Examples of fluids: blow-by gas, EGR gas).

A guide g is provided inside the side walls 8 and 9 near the opening 5 in the manifold main body 4A to guide the air toward the opening 5 to the central portion in the width direction of the opening 5. The side walls 8 and 9 are a pair of upper and lower facing side walls 8 and 9 along the direction (front-back direction) of the intake ports p1 and p2 in the manifold main body 4A. The periphery of the opening 5 is formed on a flange wall 4F equipped with an endless seal rubber 10, and the opening widths D above and below the opening 5 are set to be slightly larger than the diameters d of the intake ports p1 and p2. ing.

As shown in FIGS. 1 and 2, each of the upper and lower guides g and g has a guide surface 24 for guiding the air flow and is supported inside the upper facing side wall 8 and the lower facing side wall 9. , It is formed on a guide wall whose vertical cross-sectional shape is substantially triangular. The guide g, which is a guide wall, is formed over the entire width of the opening 5, and the end 25a on the downstream side in the air flow direction of each guide g, g has an air flow from the opening end surface 4a of the manifold main body 4A. It is moved upstream in the direction (see FIG. 1).

Each guide g may be integrally formed with the intake manifold 4, or may be fixedly supported by the manifold main body 4A (upper and lower facing side walls 8 and 9) as a separate body. The open end surface 4a of the box-shaped intake manifold 4 is surface-contacted and fixed to the right side surface 12a of the cylinder head 12 in a sealed state. In FIG. 1, 31 is an intake valve, 32 is a coil spring, 33 is a rocker arm, 34 is a piston, and 35 is a combustion chamber.

Each of the upper and lower guides g has an end surface 25 that is inclined with an end 25a that is closest to the intake port side at a corner, and between these end surfaces 25 and the right side surface 12a of the cylinder head 12. Step space portions 26 having a small volume are formed on the upper and lower sides, respectively. The distance t between the upper and lower ends 25a and 25a is slightly smaller than the diameter (diameter) d of the intake port p [see FIG. 2B].

The step space portion 26 does not extend the guide g to the opening end surface 4a by utilizing the fact that the opening width D of the opening 5 is larger than the diameter d of the intake port p, so that the guide g is slightly inside (suction). It is formed as a space portion surrounded by the end face 25 due to being brought closer to the portion 4B side). The inclination of the end face 25 may be an angle opposite to the overhang angle shown in FIG. 1 or may be no angle (vertical wall).

Next, the action and effect of providing the guide g will be described.
As shown in FIG. 1, the air sucked into the intake manifold 4 from the suction unit 4B flows to the intake port p (p1) through the suction path 4W as shown by the white arrow, but the upper and lower guides The guide surface 24 of g allows air to smoothly enter the intake port p. In addition, when air exceeds the guide surface 24, turbulent energy that is not attenuated is generated in the "small inertial region" according to "Kolmogorov's minus 5/3 power measurement", which promotes the mixing of fuel and air and activates combustion. Will be transformed.

A head surface step is generated because the vertical width (opening width) D of the opening 5 is larger than the diameter d of the intake port p, but the guidance action by the guide g suppresses or eliminates the retention of air at the head surface step. Will be done. The pulsating group from the head port of the cylinder head 12 flows back toward the intake manifold 4 along the inner peripheral surface of the intake port p (see the solid arrow in FIG. 1), and the pulsating group is the guide g. It is received by the end face 25 of the above, and the backflow to the intake manifold 4 is suppressed. That is, it can be expected that the pulsating group that flows backward hits the end face 25 and stays in the step space 26 and disappears spontaneously.

As a result, the following effects (1) to (8) can be obtained.
(1) Combustion is activated, and the amount of black smoke and PM generated can be reduced.
(2) Combustion is activated and the fuel consumption rate can be improved.
(3) Combustion is activated, and blue-white smoke in cold weather caused by unburned fuel is suppressed.
(4) Combustion is activated and startability in cold weather is improved.
(5) Combustion is activated, the ignition delay period is shortened, the premixed combustion region is reduced, and noise and vibration can be reduced.

(6) Since the air density can be increased, the output can be increased without increasing the displacement.
(7) Since the air density can be increased, it is possible to reduce black smoke emission in highlands.
(8) Since the intake air temperature can be lowered, the amount of NOx discharged can be reduced.

[Another Embodiment 1]
As shown in FIG. 5A, an intake device A having a box-type intake manifold 4 for a 3-cylinder engine corresponding to the first to third intake ports p1, p2, p3 may be used. The cross-sectional shape of the guide g is the same as that shown in FIG. 1, but the guide g is provided at a total of 6 places independently (discontinuously) at the top and bottom corresponding to the intake ports p1, p2, p3 at the opening 5. Has been done.

An arc-shaped guide g that connects and connects the upper and lower guides g and g may be provided so as to correspond to the first and third intake ports p1 and p3. Further, although not shown, a configuration in which adjacent linear guides g and g are connected to form a pair of continuous wide guides g and g similar to those shown in FIG. 2 (B) may be used.

[Separate Embodiment 2]
As shown in FIG. 5 (B), a plurality of (three) branched short-length branch pipe portions 4C, 4C, and 4C corresponding to the first to third intake ports p1, p2, and p3 are the manifold main body. An intake device A provided with an intake manifold 4 formed in the portion 4A, that is, a so-called branched type intake manifold 4, may be used. The action and effect of the guide g is mainly observed in the box-type intake manifold, but the effect can also be expected in the branched intake manifold.

In the opening 5 corresponding to the first intake port p1, the guide g is formed as an annular shape, and the diameter of the guide g (notation omitted) is slightly smaller than the diameter d of the first intake port p1. In this case, the "width direction" of the "central portion in the width direction of the opening 5" is the "diameter direction" of the circular opening 5.
In the opening 5 corresponding to the second intake port p2, a pair of guide g is formed vertically in each of the front and rear directions. In this case, the "width direction" of the "central portion in the width direction of the opening 5" is the "front-back direction" of the circular opening 5.

In the opening 5 corresponding to the third intake port p3, a pair of guide g is formed laterally on each of the upper and lower sides. In this case, the "width direction" of the "central portion in the width direction of the opening 5" is the "vertical direction" of the circular opening 5.
As described above, the guide g can be changed and set in various ways such as its combination and selection.

[Another Example]
The present invention can be applied even in an intake device in which the opening width D of the opening 5 and the diameter d of the intake port p have a relationship of D ≦ d.

4 Intake manifold 4A Manifold body 4B Suction 4a Open end face 5 Open (1 opening)
8 side wall (upper facing side wall)
9 side wall (lower facing side wall)
24 Guide surface 25a End D Opening width d Intake port diameter g Guide p Intake port p1 First intake port p2 Second intake port p3 Third intake port

Claims (5)

A manifold main body having an opening corresponding to an intake port and an intake manifold having an air intake are provided.
The opening is set to one opening formed so as to cover all of the plurality of intake ports.
Inside the side wall near the opening in the manifold body, a guide is provided to guide air toward the opening to the center in the width direction of the opening .
The guide is an engine intake device formed over the entire width of the opening in the direction in which the intake ports are arranged. The intake device for an engine according to claim 1, wherein the side wall is a pair of opposite side walls along the arrangement direction of the intake ports in the manifold main body. The intake device for an engine according to claim 1 or 2, wherein the end on the downstream side in the air flow direction of the guide is moved to the upstream side in the air flow direction with respect to the open end surface of the manifold main body. The intake device for an engine according to any one of claims 1 to 3, wherein the opening has an opening width larger than the diameter of the intake port. The intake device for an engine according to any one of claims 1 to 4, wherein the guide has a guide surface for guiding an air flow and is formed on a guide wall supported inside the side wall.

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