JPH0517149U - Engine intake passage structure - Google Patents

Abstract

(57) [Abstract] [Purpose] The upstream ends of the collective intake passages 12F, 12R for each of a plurality of cylinder groups, which are composed of cylinders 2, 2, ... Which are not adjacent to each other in the intake stroke of the engine 1, are partitioned by a partition wall This common intake passage 14 is connected to one common intake passage 14.
In the intake passage structure in which one throttle valve 16 is arranged with the valve shaft 16a in the same direction as the surface of the partition wall 15, the recirculation exhaust gas introduced downstream of the throttle valve 16 can be distributed to a plurality of cylinder groups. Increase. [Structure] An expansion chamber 17 is formed between a throttle valve 16 and a partition wall 15, and a partition plate 21 in the same direction as the partition wall 15 is arranged in the expansion chamber 17 so that the intake air is higher than the partition plate 21. The recirculation exhaust gas introduction port 22 is opened in the protruding direction of the partition plate 21 on the radially outer side of the passage.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an intake passage structure of an engine, and more particularly to an intake passage structure for improving the distribution of recirculated exhaust gas.

[0002]

[Prior Art]

 Conventionally, various techniques have been proposed for returning the recirculated exhaust gas to the intake system. For example, in the one disclosed in Japanese Utility Model Laid-Open No. 22660/1990, an intake passage (resonance passage) upstream of a surge tank for each cylinder group causing resonance supercharging of intake air and downstream of a throttle valve for each cylinder group. The downstream end of the exhaust gas recirculation passage is opened to improve the distribution of the recirculated exhaust gas to each cylinder group.

Further, in Japanese Utility Model Laid-Open No. 1-166253, in the case where exhaust gas is recirculated into a surge tank, a radial groove is formed at the upstream end on the throttle valve side in the surge tank. It has been shown that introducing exhaust gas into the groove improves the distribution of exhaust gas to each cylinder.

By the way, conventionally, as disclosed in Japanese Patent Application Laid-Open No. 1-280630, an intake passage on the downstream side of one throttle valve is branched into an intake passage for each of the left and right cylinder groups, and the intake passage causes resonance of intake air. An intake device is known which is designed to obtain a supercharging effect.

[0005]

[Problems to be solved by the device]

 In order to obtain such a resonance supercharging effect, or to prevent intake interference between cylinders to reduce intake resistance and increase intake charge, a plurality of cylinders of an engine are not adjacent to each other in intake stroke. Cylinders are grouped together to be divided into a plurality of cylinder groups, and the collective intake passage upstream parts of the cylinder groups gathered on the upstream side of the independent intake passages communicating with the plurality of cylinder groups are gathered together to form one throttle. An intake passage structure that connects to a common intake passage with a built-in valve is adopted.

In this case, in order to make the size of the intake system compact and make the intake passage length for each cylinder group equal, the collective intake passages for each cylinder group downstream of the throttle valve are separated by a partition wall. If the throttle valve is placed with its valve axis horizontal, the valve axis of the throttle valve and the surface of the partition wall are aligned in the same direction.

However, in a low load state of the engine in which the opening of the throttle valve is small, intake air (air) is guided by a throttle valve inclined with respect to the intake passage, so that the intake air (air) is rotated downstream of the valve shaft of the throttle valve. The intake flow velocity at the dynamic end becomes faster than the upstream rotational end, and the intake velocity to the cylinder group corresponding to the downstream rotational end becomes higher. Therefore, when the recirculation exhaust gas is introduced into the common intake passage on the downstream side of the throttle valve when the engine load is low, there is a problem that the distribution of the recirculation exhaust gas to the cylinder group is impaired due to the uneven intake flow velocity. is there.

The present invention has been made in view of the above points, and an object thereof is to improve the structure of the intake passage on the downstream side of the throttle valve so as to solve the problem caused by the deviation of the intake flow velocity when the throttle opening is small. This is to solve the problem and to ensure good distribution of the recirculated exhaust gas to each cylinder group.

[0009]

[Means for Solving the Problems]

 In order to achieve this object, in the invention of claim 1, an expansion chamber for forming a uniform intake flow velocity is formed between the partition wall and the partition wall on the downstream side of the throttle valve, and this expansion chamber has the same direction as the partition wall. The partition plate is arranged so that the recirculated exhaust gas introduced into the expansion chamber is divided into each cylinder group by this partition plate.

Specifically, according to the present invention, a plurality of cylinders of an engine are collected by cylinders which are not adjacent to each other in intake stroke to be divided into a plurality of cylinder groups, and the cylinder groups are communicated with each other. Collected intake passages for each cylinder group, which are collected on the upstream side of the independent intake passages, are assembled together and connected to a common intake passage containing one throttle valve. It is premised on the engine intake passage structure in which the passages are separated by a partition wall that has a surface in the same direction as the valve axis of the throttle valve.

An expansion chamber having an inner wall that is larger in the radial direction than the inner wall of the common intake passage is provided between the throttle valve and the partition wall, and the partition is located in a region that bulges in the radial direction of the expansion chamber. A partition plate extending in the same direction as the wall is projected. Further, the recirculation exhaust gas introduction port is opened radially outward of the common intake passage with respect to the partition plate in the same direction as the protruding direction of the partition plate.

According to the second aspect of the invention, in the expansion chamber between the throttle valve and the partition wall, there is provided an opening extending in the direction orthogonal to the common intake passage and having a passage cross-sectional area smaller than the passage cross-sectional area of the expansion chamber. The plate having the plate is interposed to divide the expansion chamber into the upstream and downstream sides, and the partition plate is formed on the plate.

[0013]

[Action]

 With the above configuration, in the device of claim 1, the expansion chamber having the inner wall radially larger than the inner wall of the common intake passage is provided between the throttle valve and the partition wall. When the opening of the throttle valve is small in the load range, even if intake air passes through the throttle valve with a small opening with different flow velocities at its downstream and upstream rotational ends, it will flow into the expansion chamber. The flow velocity is suppressed and becomes stagnant, which suppresses the deviation of the intake flow velocity on the downstream side of the throttle valve. Moreover, a partition plate in the same direction as the partition wall is arranged in the expansion chamber, and the recirculation exhaust gas inlet is open in the protruding direction of this partition plate, so that part of the exhaust gas is discharged when the engine is under low load. When the gas is recirculated, the exhaust gas sucked into the expansion chamber from the above-mentioned inlet hits the partition plate and is evenly divided. Then, the exhaust gas is mixed with the intake air whose flow velocity has decreased in the expansion chamber and stirred. Therefore, the recirculation exhaust gas flows into both of the intake passages divided by the partition wall equally, and even if the valve shaft of the throttle valve is arranged in the same direction as the partition wall, the recirculation exhaust gas to the cylinder group is recirculated. Good distribution of exhaust gas can be ensured.

According to the second aspect of the invention, since the expansion chamber is divided into the upstream side and the downstream side by the plate, the intake air that has passed through the throttle valve and flowed into the expansion chamber has a flow velocity in the upstream expansion chamber. After being lowered, it flows through the opening of the plate into the downstream expansion chamber, where it settles again and the flow velocity decreases. Therefore, it is possible to further suppress the deviation of the intake flow velocity that occurs after passing through the throttle valve, and to achieve a more effective even distribution of the recirculated exhaust gas.

Further, even if the pressure wave of intake air propagates to the upstream side of the collective intake passage in the resonance supercharging state, the pressure wave is blocked by the plate and is suppressed from being transmitted to the upstream side. Since the partition plate is formed on this plate, it is possible to effectively prevent the recirculated exhaust gas from being blown back to the throttle valve side by the intake pressure wave.

[0016]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 shows an intake system of a V-type 6-cylinder engine according to an embodiment of the present invention. Reference numeral 1 denotes a V-type 6-cylinder engine mounted horizontally on a vehicle body so that an output shaft (not shown) extends in the vehicle width direction. The engine 1 is a pair of banks BF facing each other in the front and rear direction. Have BR. The front bank BF has the first, third and fifth three cylinders 2, 2, ... And the rear bank B R has the second, fourth and sixth three cylinders 2, 2, 2. ... are formed respectively. The intake strokes of these six cylinders 2, 2, ... Are arranged in the order of the cylinder numbers, and the six cylinders 2, 2, ... Are combined for each bank BF, BR by cylinders whose intake strokes are not adjacent to each other. It is divided into two cylinder groups.

An intake manifold 3 which is basically formed by casting is arranged above the engine 1. This manifold 3 has a pair of front and rear surge tanks 4F and 4R corresponding to the cylinder groups in each bank BF and BR, and these surge tanks 4F and 4R are both arranged above the rear bank BR, and They extend parallel to each other in the bank length direction (vehicle width direction). Specifically, the front surge tank 4F is arranged above the front end of the rear bank BR, and the rear surge tank 4R is arranged above the rear end of the rear bank BR and at a lower height than the front surge tank 4F. There is. On the front side surface of the front surge tank 4F, the upstream ends of three independent intake passages 5F, 5F, ... Are branched at equal intervals, and each independent intake passage 5F extends forward between the banks BF, BR. After that, it is bent downward, and its downstream end is connected to each cylinder 2 of the front bank BF. On the other hand, similarly, on the front side surface of the rear surge tank 4R, the upstream ends of three independent intake passages 5R, 5R, ... Are branched at equal intervals, and each independent intake passage 5R is connected to the rear bank BR. It extends upward and bends downward, and its downstream end is connected to each cylinder 2 of the rear bank BR.

The right end portions of both surge tanks 4F and 4R are communicated with each other by a first communication passage 6, and the right end portion of the rear surge tank 4R to which this communication passage 6 is connected is connected by a negative pressure actuator 7. A first shutter valve 8 which is a butterfly valve for switching communication and disconnection in the passage 6 is provided. The surge tanks 4F and 4R are communicated with each other by a substantially L-shaped second communication passage 9 at a substantially central portion in the longitudinal direction (horizontal direction). A second shutter valve 11, which is a butterfly valve that opens and closes the communication passage 9 by a negative pressure actuator 10, is arranged at the rear portion of the second communication passage 9. The first and second shutter valves 8 and 11 are controlled to open and close according to the engine speed. For example, in the low speed range of the engine 1, both shutter valves 8 and 11 are closed. In the speed range, only the first shutter valve 8 is opened, and in the high speed range, both shutter valves 8 and 11 are opened.

Further, the left end of the front surge tank 4F is connected to the downstream end of the front collecting intake passage 12F, and the left end of the rear surge tank 4R is connected to the downstream end of the rear collecting intake passage 12R. The upstream ends of the intake passages 12F and 12R are connected to one common intake passage 14 formed in the throttle body 13, where the collective intake passages 12F and 12R join each other. Then, as shown in FIGS. 1 and 2, the two collective intake passages 12F, 12R are partitioned by a horizontal partition wall 15 at the upstream end, and are vertically stacked.

Further, one throttle valve 16 consisting of a butterfly valve is arranged in the throttle body 13, and its valve shaft 16a is in the same horizontal direction as the partition wall 15 at the upstream end of the collective intake passages 12F, 12R. It is extended. The throttle valve 16 rotates about the valve shaft 16a, but the lower rotation end 16b of the valve shaft 16a is downstream of the valve shaft 16a, and the upper rotation end 16c thereof is upstream of the valve shaft 16a. When the opening degree is increased, the rotation ends 16b and 16c are rotated counterclockwise in FIG. 1 so that both rotation ends 16b and 16c are separated from the inner wall of the throttle body 13.

Further, as a feature of the present invention, the downstream end of the throttle body 13 having the above-mentioned throttle valve 16 and the upstream of the intake manifold 3 forming the collective intake passages 12F, 12R separated by the partition wall 15. Each side end portion is expanded radially outward, and as shown in FIG. 3, the side end portions have an inner wall that is larger in radial direction than the inner wall of the common intake passage 14 in the throttle body 13 and has a rectangular cross section. A chamber 17 is formed.

Further, between the throttle valve 16 in the throttle body 13 and the partition wall 15 on the upstream side of the collective intake passages 12F, 12R, a vertical direction which is orthogonal to the flow direction of intake air in the common intake passage 14 is provided. A plate 18 extending in the direction is arranged. The plate 18 is interposed between the throttle body 13 and the upstream end of the intake manifold 3 in an airtight state. As shown in FIG. 3, a common intake passage 14 is formed in the center of the plate 18. A rectangular opening 19 is formed, and the opening 19 has a passage sectional area smaller than the passage sectional area of the expansion chamber 17. With this structure, the expansion chamber 17 is divided into the upstream expansion chamber 17U and the downstream expansion chamber 17D by the plate 18, and the expansion chambers 17U and 17D are connected to each other through the opening 19 (common intake passage 14).

A projecting portion 20 extending toward the downstream side is integrally formed on the upper edge of the opening 19 of the plate 18, and a vertical direction extends from the upper surface of the central portion of the projecting portion 20 to the downstream side surface of the plate 18 above the opening 19. A partition plate 21 extending in the direction of the arrow is projected. Further, a recirculation exhaust gas inlet 22 is provided on the upper wall of the upstream end portion of the intake manifold 3 forming the combined intake passages 12F and 12R, and is partitioned outward of the common intake passage 14 in the radial direction with respect to the partition plate 21. Although not shown, the inlet 22 is connected to the exhaust passage of the engine 1 so that part of the exhaust gas is returned to the common intake passage 14 from the inlet 22. ing.

Therefore, in the above-described embodiment, the resonance effect of intake air is generated in the low and medium speed range of the engine 1, and the intake charge amount in each cylinder 2 is increased by this resonance effect to increase the output torque of the engine 1. To do. That is, the first and second shutter valves 8 and 11 are opened / closed according to the rotation range of the engine 1, and the rotational speed of resonance effect tuning is switched. Specifically, for example, when the engine 1 is in the low speed range, both the first and second shutter valves 8 and 11 are closed, and the synchronized rotation speed is in the low speed range. In this state, the basic pressure wave of the intake air generated in the intake ports of the cylinders 2, 2 ... of the banks BF, BR is reversed on the upstream side of the intake passages. The pressure reversal part is located at the upstream end of the intake passages 12F, 12R. The pressure wave of the intake air, which is in the tor body 13 and propagates back and forth between the throttle body 13 and each cylinder 2, resonates in the intake passage, and due to this resonance, the pressure vibration individually generated in each cylinder 2 causes a large vibration. A resonance pressure wave having an amplitude is generated, and the resonance pressure wave causes the intake air to be pushed into the combustion chamber of the cylinder 2 to increase its filling rate. As a result, the output torque of the engine 1 in the low speed range can be increased.

When the engine 1 shifts to the medium speed range, the second shutter valve 11 remains closed and only the first shutter valve 8 is opened to open the first communication passage 6, so that the resonance effect can be adjusted. The rotation speed shifts to the medium speed range. In this state, the pressure reversal portion of the pressure wave of the intake air becomes the first communication passage 6, and the pressure wave of the intake air that reciprocates between the communication passage 6 and each cylinder 2 resonates in the intake air passage. By this resonance pressure wave, the intake air is pushed into the combustion chamber of the cylinder 2 and the filling rate thereof is increased, so that the output torque in the medium speed range of the engine 1 can be increased.

When the engine speed further increases to reach the high speed range, both the first and second shutter valves 8 and 11 are opened and the first and second communication passages 6 and 9 are opened. In this state, the above-mentioned resonance effect disappears, so that the valley of torque can be reduced. As described above, the output torque can be increased from the low speed region to the high speed region of the engine 1.

When the opening degree of the throttle valve 16 is small in the low load range of the engine 1, intake air is guided by the throttle valve 16 inclined with respect to the common intake passage 14 and is below the valve shaft 16 a of the throttle valve 16. The intake flow velocity at the turning end 16b becomes faster than that at the upper turning end 16c. Since the valve shaft 16a of the throttle valve 16 and the surface of the partition wall 15 coincide with each other in the same direction, the cylinder group of the rear bank BR corresponding to the lower turning end 16b of the throttle valve 16 is left as it is. The intake speed to the cylinder is higher than that of the cylinders in the front bank BF. However, in this embodiment, between the throttle valve 16 and the partition wall 15, an expansion chamber 17 having an inner wall that is larger in the radial direction than the inner wall of the common intake passage 14 is provided. Since it is divided into the upstream and downstream expansion chambers 17U and 17D, the intake air that has flowed into the expansion chamber 17 through the throttle valve 16 first becomes stagnant in the upstream expansion chamber 17U and the flow velocity decreases. Then, it flows into the downstream expansion chamber 17D through the opening 19 of the plate 18, and is settled again in this expansion chamber 17D and the flow velocity decreases. As a result, the deviation of the intake flow velocity on the downstream side of the throttle valve 16 is efficiently suppressed. Since the recirculation exhaust gas introduction port 22 is opened 19 in the downstream expansion chamber 17D, if a part of the exhaust gas is recirculated when the engine 1 has a low load, the exhaust gas sucked from the introduction port 22 becomes It is mixed with the intake air whose flow velocity has decreased in the expansion chamber 17 and agitated. As a result, the recirculated exhaust gas equally flows into both of the collective intake passages 12F and 12R divided by the partition wall 15, so that the valve shaft 16a of the throttle valve 16 is arranged in the same direction as the partition wall 15. Even if this is done, it is possible to ensure good distribution of the recirculated exhaust gas to the cylinder group.

A partition plate 21 in the same direction as the partition wall 15 is arranged in the expansion chamber 17, and a recirculation exhaust gas introduction port 22 is opened in the projecting direction of the partition plate 21. The exhaust gas sucked into the expansion chamber 17 from the front side hits the partition plate 21 and is evenly divided. As a result, the distribution of the recirculated exhaust gas to the cylinder group can be further enhanced.

Further, since the plate 18 is arranged in the middle of the expansion chamber 17, the pressure wave of the intake air is transmitted to the upstream side of the collective intake passages 12F and 12R in the resonance supercharging state during the resonance supercharging. However, the pressure wave is blocked by the plate 18 and is suppressed from being transmitted to the upstream side. Further, since the partition plate 21 is formed on the plate 18, it is possible to effectively prevent the recirculated exhaust gas from being blown back to the throttle valve 16 side by the intake pressure wave.

In the above embodiment, the partition wall 15 of the collective intake passages 12F and 12R and the valve shaft 16a of the throttle valve 16 are aligned in the horizontal direction. However, the present invention is aligned in a direction other than the horizontal direction. It is also applicable when doing.

[0031]

[Effect of the device]

 As described above, according to the invention of claim 1, the upstream end of the collective intake passage for each of a plurality of cylinder groups including the cylinders that are not adjacent to each other in the intake stroke is partitioned by the partition wall into one common intake passage. In the intake passage structure in which one throttle valve is connected to this common intake passage and the valve shaft is arranged in the same direction as the surface of the partition wall, an expansion chamber is formed between the throttle valve and the partition wall. A partition plate in the same direction as the partition wall was placed in this expansion chamber, and the recirculation exhaust gas inlet was formed in the partition plate protruding direction radially outside the partition plate, so the throttle valve opening If the deviation of the intake flow velocity occurs at the rotational ends upstream and downstream of the valve shaft of the throttle valve when the degree is low, it can be compensated for by the stagnation of intake air in the expansion chamber, and the throttle valve is small. From the inlet when the engine load is low The recirculation exhaust gas introduced into the large chamber can be separated by a partition plate, so that the recirculation exhaust gas can be evenly distributed from one recirculation exhaust gas inlet to a plurality of cylinder groups to improve its distribution. You can

According to the invention of claim 2, since the expansion chamber is divided into two along the flow direction of the intake air by the plate having the opening, and the partition plate is formed on the plate, the upstream divided by the plate The deviation of the intake flow velocity in each of the expansion chambers on the downstream side and the downstream side can be more effectively suppressed, and the distribution of the recirculated exhaust gas can be improved more effectively. The exhaust gas from the inlet can be prevented from entering the throttle valve side by blocking the plate with a plate.

[Brief description of drawings]

FIG. 1 is a cross-sectional view taken along the line II of FIG.

FIG. 2 is a sectional view taken along line II-II of FIG.

3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a plan view showing an intake system of the engine.

[Explanation of symbols]

 1 ... Engine 2 ... Cylinder 5F, 5R ... Independent intake passage 12F, 12R ... Collective intake passage 13 ... Throttle body 14 ... Common intake passage 15 ... Partition wall 16 ... Throttle valve 16a ... Valve shaft 17 ... Expansion chamber 17U ... Upstream expansion Chamber 17D ... Downstream expansion chamber 18 ... Plate 19 ... Opening 21 ... Partition plate 22 ... Recirculation exhaust gas inlet

Claims (2)

[Scope of utility model registration request] 1. A plurality of cylinders of an engine are assembled into cylinders which are not adjacent to each other in intake stroke and are divided into a plurality of cylinder groups, and are assembled on the upstream side of an independent intake passage communicating with each of the plurality of cylinder groups. The upstream portions of the collective intake passage for each cylinder group are assembled together and connected to a common intake passage having one built-in throttle valve, and the collective intake passages for each cylinder group downstream of the throttle valve are connected to the valve shaft of the throttle valve. In an intake passage structure of an engine separated by a partition wall having a surface in the same direction, between the throttle valve and the partition wall, an expansion chamber having an inner wall radially larger than an inner wall of the common intake passage is provided. A partition plate extending in the same direction as the partition wall is provided in a projecting position in the radial direction of the expansion chamber, and the partition plate is located radially outward of the common intake passage relative to the partition plate in the same direction as the partition plate protruding direction. An intake passage structure for an engine, characterized in that a recirculation exhaust gas inlet is opened. 2. The intake passage structure for an engine according to claim 1, wherein a passage extending in a direction orthogonal to the common intake passage and having a passage cross-sectional area smaller than that of the extension chamber is provided in the enlargement chamber between the throttle valve and the partition wall. An intake passage structure for an engine, characterized in that a plate having an opening having a cross-sectional area is interposed, the expansion chamber is partitioned on the upstream and downstream sides by the plate, and a partition plate is formed on the plate.