JP2000274321A - Suction device of v-type internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the suction performance of a V-type internal combustion engine and to realize its compact size. SOLUTION: This device is provided with joining passages 4 erecting upward obliquely from the suction port inlets of the cylinders of both the left side and the right side banks, long size passages 5 extending from the upper ends of the passages 4 to the opposite side bank sides, and bent downward and opened at the lower parts, short size passages 6 branched from the downstream sides of the center between banks of the long size passages 5, and extended downward obliquely, a collector part 7 formed in a box form suction passage 3 at the outer side of the long size passages 5 and the short size passages 6, passage change-over valves 8 provided in the short size passages 6, and driving shafts 9 and 10 connecting the passage change-over valves 8 of the cylinder group side of the same bank.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake device for a V-type internal combustion engine, and more particularly to a technique for achieving both intake performance and compactness.

[0002]

2. Description of the Related Art As an intake device for a V-type internal combustion engine, there is, for example, one disclosed in Japanese Patent Application Laid-Open No. 7-197817. In this configuration, a merging passage portion extending diagonally upward from an intake port inlet of each cylinder formed in each of the banks on the left and right sides of the V-type internal combustion engine to a center portion between the banks, and a curved upper and lower portion of the merging passage portion A long passage extending from the inside of the curve of the long passage, a short passage branching downward from the inside of the curve of the long passage, and a collector (surge tank) surrounding the lower end openings of the long passage and the short passage from below. ), A passage switching valve for opening and closing the passage is provided in each of the short passages, and each passage switching valve is driven to open and close by a single drive shaft, thereby reducing the equivalent length of the intake passage to engine rotation. Switching is performed in accordance with the speed, and always attempts to obtain good inertial supercharging performance.

[0003]

However, in the conventional intake device for a V-type internal combustion engine, the upper portions of the short passages are arranged in a straight line in the crankshaft direction, and the passages arranged in this portion are arranged in a straight line. Since the switching valve is driven by one drive shaft, the degree of freedom of the mounting position of the passage switching valve is small, and the opening area of the short passage cannot be increased, so that the ventilation resistance increases. Since the short passage has to be bent at a right angle or a larger angle downward from the merging passage, the ventilation resistance of the short passage has been further increased. Further, since the passage switching valves are arranged in a line in the direction of the crankshaft, it is difficult to make the intake device compact, and the intake device protrudes upward and the height of the engine may increase.

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems, and an object of the present invention is to provide an intake device for a V-type internal combustion engine, which can reduce airflow resistance and satisfy compactness.

[0005]

For this reason, the invention according to claim 1 provides a V-type internal combustion engine in which a plurality of cylinders arranged in the crankshaft direction are alternately arranged in banks on both sides forming a V-shape of a cylinder head. In each of the intake devices, an upstream intake passage connected to an inlet of an intake port for each cylinder formed in each of the banks is opened at upper ends on both sides of a box-shaped intake passage arranged between both banks. A merging passage section connecting an intake outlet of each cylinder and an intake port inlet of a corresponding cylinder formed in a bank close to the intake outlet, and from the respective intake outlets to the opposite side along the upper portion of the box-shaped intake passage. A long passage portion formed by partitioning the inside of the box-shaped intake passage so as to be bent downward and open at the lower portion after being extended, and a center of the box-shaped passage at a portion along the upper portion of the box-shaped intake passage of the long passage portion Branches from the intake outlet side more and the opposite A short passage portion formed so as to open toward the front, and an upstream collector portion formed outside the long passage portion and the short passage portion in the box-shaped intake passage. A passage switching valve interposed in the short passage portion to open and close the passage according to the engine operating state; and two drive shafts that respectively connect and drive the passage switching valves corresponding to the cylinders on the same bank. , Are provided.

According to the first aspect of the present invention, each passage switching valve is fully closed in accordance with the engine operating conditions, for example, in a low-to-medium speed range where the engine speed is lower than a predetermined value, by the rotational positions of the two drive shafts. And In this case, the intake air is introduced into the box-shaped intake passage from the intake pipe on the upstream side, passes through the collector portion below the box-shaped intake passage, enters the long passage portion of the cylinder in the intake stroke, and joins the converging passage portion. Through the intake port of the corresponding bank into the combustion chamber of the cylinder. As described above, since the intake passage passes through the long passage portion, the equivalent pipe length is relatively long, and high output can be ensured in conformity with inertial supercharging in a low to medium speed range.

On the other hand, for example, in a high speed region where the engine rotational speed is equal to or higher than a predetermined value, when two drive shafts are driven to switch each passage switching valve to the full open state, the intake air flows from the upstream intake pipe to the box-shaped intake passage. After being introduced into the intake passage, it passes through the collector portion below the box-shaped intake passage, enters mainly into the short passage portion of the cylinder in the intake stroke, and, through the merge passage portion, the combustion of the cylinder from the intake port of the corresponding bank. Supplied indoors. As described above, since the intake passage mainly passes through the short passage portion, the equivalent pipe length is relatively short, and high output can be ensured in conformity with inertial supercharging in a high-speed region.

Since the two drive shafts of the passage switching valve are provided offset in parallel, the degree of freedom of the mounting position of the passage switching valve is increased, and the short ends of the adjacent short passages do not interfere with each other. As a result, the effective area of the opening of each short passage can be increased, so that the ventilation resistance can be reduced.

Further, the short passage portion branches off from the center of the box-shaped passage of the long passage portion from the intake outlet side and opens toward the opposite side, so that the short passage portion forms a passage central axis with the long passage portion. The junction angle can be made acute, and the ventilation resistance of the short passage can be further reduced.

Further, since the passage switching valves are arranged in two rows for each cylinder group of each bank, the intake device can be made compact, and the intake device protrudes upward to reduce the height of the engine. Increase can also be suppressed.

The invention according to claim 2 is characterized in that a merging angle between the central axis of the short passage and the central axis of the long passage is less than 70 °.

According to the second aspect of the present invention, by reducing the merging angle θ to less than 70 °, the airflow resistance at the merging portion can be reduced. In addition, since the merging angle θ is small, the pressure wave from the cylinder is easily guided to the collector, and the inertia effect is also improved.

According to a third aspect of the present invention, the ratio L / D of the length L and the diameter D is provided on the upper portion of the box-shaped intake passage downstream of the junction of the long passage and the short passage. Has at least one straight straight portion.

According to the third aspect of the present invention, the separation at the junction of the long passage and the short passage is performed by a straight straight member having a ratio L / D of length L and diameter D of about 1 or more. The airflow resistance can be further reduced at the part, and the airflow resistance can be further reduced.

According to a fourth aspect of the present invention, the ends of the two drive shafts are symmetrically connected to the output rod of one actuator via a link mechanism, respectively. The two drive shafts rotate symmetrically at the same angle by the forward / backward stroke operation to switch each of the passage switching valves to the fully closed or fully opened state.

According to the invention of claim 4, two drive shafts can be symmetrically rotated by one actuator and can be simultaneously switched between fully closed and fully opened.

[0017]

Embodiments of the present invention will be described below. 1 to 6 show an embodiment of an intake device for a V-type internal combustion engine according to the present invention. The V-type internal combustion engine 1 includes a plurality of cylinders arranged in the
It is alternately arranged in each bank on both sides of the mold.

Each bank has an intake port 2 for each cylinder.
Is formed, and the upstream intake passage connected to the inlet of the intake port 2 is configured as follows. That is, a box-shaped intake passage 3 formed by fastening flange portions of two vertically divided members to each other is disposed at the center between the left and right banks. Each of the merging passages 4 is formed integrally with the intake outlet of each cylinder opened at the upper end on both sides and the intake port 2 entrance of the corresponding cylinder formed in the bank near the intake outlet.

In the inside of the box-shaped intake passage 3, each of the long passages extending from the respective intake outlets to the opposite side along the upper part of the box-shaped intake passage 3 and then bending downward to open at the lower part. Each of the short passages is formed by partitioning and branching from a portion of the long passage portion 5 along the upper portion of the box-shaped intake passage 3 from the center of the box-shaped passage from the intake outlet side to the opposite side. The part 6 is formed.

The outer portions of the long passage portion 5 and the short passage portion 6 in the box-shaped intake passage 3 are connected to an upstream intake collector portion 7.
An inlet 7a forming a throttle chamber of the intake collector 7 is formed in the upper center of the box-shaped intake passage 3 so as to open to the right in the drawing. An intake pipe (not shown) is connected to the inlet 7a. An auxiliary air inlet 7b for introducing auxiliary air for controlling the idling rotational speed through an auxiliary air valve (not shown) is formed on the opposite side (the right side in the figure) of the inlet 7a.

Here, the merging angle θ between the central axis of the short passage 6 and the central axis of the long passage 5 is 70.
° is set to less than. Further, a straight straight portion having a ratio L / D of length L and diameter D of approximately 1 or more on the upper side of the box-shaped intake passage 3 downstream of the junction of the long passage portion 5 and the short passage portion 6. A portion 5a is provided.

Each of the short passages 6 is provided with a passage switching valve 8 for opening and closing the passage, and each passage switching valve 8 corresponding to each cylinder on the same bank side has a common drive shaft 9. , 10.

One end of each of the drive shafts 9 and 10 is symmetrically connected to the end of the output rod 15a of the negative pressure actuator 15 via two links 11, 12, 13 and 14, respectively. . In a low-medium speed region where the engine rotation speed is lower than a predetermined value, a negative pressure such as an intake negative pressure is introduced into a pressure working chamber (not shown) of the negative pressure actuator 15, and the output rod 15
a, the passage switching valves 8 connected to the drive shafts 9, 10 at this position are fully closed. When the engine rotational speed shifts from the above state to a high speed region at or above a predetermined value, the pressure working chamber of the negative pressure actuator 15 is opened to the atmosphere, and the output rod 15a extends downward and makes a stroke integrally with the drive shaft 9. 2 and FIG.
3, the passage switching valve 8 on the right side in the figure is rotated clockwise in the figure symmetrically with the drive shaft 10 by the same rotation angle, and is fully opened.

Next, a series of operations of the present embodiment will be described. In the low-to-medium speed range where the engine speed is lower than the predetermined value, as described above, each passage switching valve 8 is fully closed. In this case, the intake air flows from the upstream intake pipe (not shown) through the box-shaped intake passage 3. After being introduced into the cylinder, as shown by the solid black line in FIG. 7, it passes through the collector section 7 below the box-shaped intake passage 3 and enters the long passage section 5 of the cylinder in the intake stroke. Is supplied from the intake port 2 of the corresponding bank into the combustion chamber of the cylinder. As described above, since the intake passage passes through the long passage portion 5, the equivalent pipe length is relatively long, and as shown in FIG. it can.

On the other hand, in the high speed region where the engine speed is equal to or higher than the predetermined value, as described above, each passage switching valve 7 is fully opened. In this case, the intake air flows from the upstream intake pipe (not shown) into a box-like shape. After being introduced into the intake passage 3, as shown by the white dotted line in FIG. 7, the gas passes through the collector portion 7 below the box-shaped intake passage 3 and mainly enters the short passage portion 6 of the cylinder in the intake stroke. The fuel is supplied from the intake port 2 of the corresponding bank into the combustion chamber of the cylinder via the passage 4. Although the long passage portion 5 is also open, the intake passage mainly enters the short passage portion 6 because the passage length is longer and the ventilation resistance is larger than that in the short passage portion 6. As described above, since the intake passage mainly passes through the short passage 6, the equivalent pipe length is relatively short, and as shown in FIG. 8, high output can be ensured in conformity with inertial supercharging in a high-speed region.

Then, the drive shafts 9, 10 of the passage switching valve 8 are connected to 2
By providing the main passages in parallel, the opening ends of the adjacent short passages 6 can be arranged so as not to interfere with each other, whereby the effective area of the opening of each short passage 6 can be increased. Therefore, the ventilation resistance can be reduced.

When the vehicle passes through the short passage portion 6 in the high-speed region, the merging angle θ between the long passage portion 5 and the central axis of the passage is formed.
Is reduced to less than 70 °, so that the airflow resistance can be reduced, and the separation at the confluence point is performed by a straight straight portion having a ratio L / D of length L and diameter D of about 1 or more. It can be recovered and the airflow resistance can be further reduced (see FIGS. 9 and 10). In addition, since the merging angle θ is small, the pressure wave from the cylinder is easily guided to the collector 7, so that the inertia effect is also improved.

Further, since the passage switching valve 8 is arranged in two rows for each cylinder group of each bank, the intake device can be made compact, and the intake device projects upward and the height of the engine increases. Can be suppressed from increasing.

[Brief description of the drawings]

FIG. 1 is a plan view of an intake device for a V-type internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is a sectional view taken along the line BB in FIG. 1;

FIG. 4 is a view taken in the direction of arrow C in FIG. 1;

FIG. 5 is a bottom view of the intake device.

6 is a view as viewed in the direction of the arrow X in FIG. 3;

FIG. 7 is a perspective view showing a flow of intake air of the intake device.

FIG. 8 is a characteristic diagram of volumetric efficiency of the intake device with respect to engine speed.

FIG. 9 is a characteristic diagram of a volume efficiency with respect to a merging angle of a long passage portion and a short passage portion in the embodiment.

FIG. 10 shows the length L of the straight portion in the embodiment.
The characteristic diagram of the volume efficiency with respect to the ratio L / D of diameter and diameter D.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 V-type internal combustion engine 2 intake port 3 box-shaped intake passage 4 merge passage 5 long passage 6 short passage 7 collector 8 passage switching valve 9, 10 drive shaft 11, 12, 13, 14 link 15 negative pressure actuator

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 35/10 301P F-term (Reference) 3G031 AB08 AC03 BA02 BA08 BA14 BB05 DA03 DA12 DA32 DA37 EA02 FA03 GA06 GA07 GA08 HA01 HA04 HA08 HA10

Claims (4)

[Claims] 1. An intake device for a V-type internal combustion engine in which a plurality of cylinders arranged in a crankshaft direction are alternately arranged in banks on both sides forming a V-shape of a cylinder head, wherein the cylinders formed in each of the banks are provided. An upstream intake passage connected to the inlet of each intake port is provided with an intake outlet for each cylinder opened at the upper end on both sides of a box-shaped intake passage arranged between the banks on both sides, and a bank near the intake outlet. And a merging passage portion that connects the intake port inlet of the corresponding cylinder formed at the upper portion of the box-shaped intake passage from the respective intake outlets to the opposite side, and further bends downward to open at the lower portion. A long passage portion formed by partitioning the inside of the box-shaped intake passage, and branching from a portion of the long passage portion along the upper portion of the box-shaped intake passage from the center of the box-shaped passage on the intake outlet side,
A short passage portion formed to open toward the opposite side, and an upstream collector portion formed outside the long passage portion and the short passage portion in the box-shaped intake passage; A passage switching valve interposed in each of the short passage portions for opening and closing the passage according to the engine operating state, and each of the passage switching valves corresponding to each cylinder on the same bank side being connected to each other to be driven 2
An intake device for a V-type internal combustion engine, comprising: a plurality of drive shafts; 2. The V-type internal combustion engine according to claim 1, wherein a merging angle between a passage central axis of the short passage and a passage central axis of the long passage is less than 70 °. Intake device. 3. A straight straight portion having a ratio L / D of a length L to a diameter D of approximately 1 or more downstream of a junction of a long passage portion and a short passage portion above the box-shaped intake passage. 3. The intake device for a V-type internal combustion engine according to claim 1, wherein the intake device includes a unit. 4. An end of each of the two drive shafts is symmetrically connected to an output rod of one of the actuators via a link mechanism, and the two output shafts are moved by a reciprocating stroke of the output rod of the actuator. The V-shape according to any one of claims 1 to 3, wherein the drive shafts are rotated symmetrically at the same angle to switch each of the passage switching valves to a fully closed state or a fully opened state. An intake device for an internal combustion engine.