JP7110584B2 - engine intake mechanism - Google Patents

Description

The present invention relates to an intake mechanism for an engine.

The exhaust gas recirculation device that recirculates engine exhaust to the intake side includes a high-pressure exhaust recirculation passage that directly recirculates exhaust gas from the exhaust manifold connected to the engine to the intake manifold, and a compressor from the downstream side of the turbocharger turbine. Some have a low-pressure exhaust gas recirculation passage that recirculates the exhaust gas upstream of and supercharges the exhaust gas together with fresh air.

In an engine equipped with a supercharger, the intake pressure may become higher than the exhaust pressure depending on the supercharging region, and the exhaust gas cannot be recirculated through the high-pressure exhaust gas recirculation passage. Even in such a supercharging region, the exhaust gas can be recirculated through the low-pressure exhaust gas recirculation passage.

However, in the low-pressure exhaust gas recirculation passage, high-temperature exhaust gas is mixed with fresh air and then cooled by the intercooler. condensed water may occur. As long as the condensed water is evenly distributed to each cylinder of the engine and flows into each cylinder, the condensed water evaporates with the combustion in each cylinder and does not cause any particular problem. However, depending on the driving conditions of the vehicle, the intake pipe may be blocked by the condensed water accumulated in the intake pipe, or the condensed water may concentrate only in a specific cylinder, which may adversely affect the combustion state of the engine. There is fear.

In order to prevent this, for example, in the intake manifold shown in Patent Document 1, a receiving surface portion formed in the vicinity of the intake port on the inner wall surface of the surge tank portion into which intake air mixed with exhaust gas is introduced, and this receiving surface portion A configuration is adopted in which a protruding portion having a guide surface portion that continues to the bottom is formed. By forming the projecting portion in this way, the condensed water received by the receiving surface portion can be gradually dropped downward while being transmitted along the guide surface portion, preventing the condensed water from concentrating only on a specific cylinder. (see paragraphs 0017 to 0024 and FIG. 3 of Patent Document 1).

Further, in Patent Document 2, exhaust gas is introduced into a chamber arranged in an intake system of a multi-cylinder internal combustion engine, and exhaust gas is introduced into an intake branch channel from an exhaust distribution channel for each cylinder arranged and opened in this chamber. In the intake system exhaust introduction structure, a structure is adopted in which a movement resistance portion (rib) is formed in the chamber to act as resistance when the condensed water moves in the arrangement direction of the exhaust distribution passages. By forming the movement resistance portion in this way, when acceleration acts on the internal combustion engine, the condensed water is prevented from moving in the arrangement direction of the exhaust distribution passage, and the condensed water concentrates only in a specific cylinder. (see paragraphs 0010 to 0015, FIGS. 5, 6, etc. of Patent Document 2).

Further, the intake device disclosed in Patent Document 3 employs a configuration in which protrusions are formed between a plurality of introduction holes for each cylinder through which exhaust gas is introduced. By forming the protrusion in this way, even if acceleration acts on a specific side of the pipe, the flow of condensed water is blocked by the protrusion. Therefore, it is possible to prevent the condensed water from concentrating only on specific introduction holes for individual cylinders (see paragraphs 0011 to 0012 of Patent Document 3, FIG. 1, etc.).

JP 2008-286069 A Japanese Patent No. 5737020 Japanese Patent No. 5505255

In the configuration according to Patent Document 1, since the condensed water is gradually guided by the guide surface portion in the direction in which the cylinders are arranged, the condensed water is likely to be affected by centrifugal force due to turning of the vehicle, and the distribution of the condensed water may become uneven. There is In addition, in the configurations according to Patent Documents 2 and 3, while it is possible to prevent the concentration of condensed water in a specific cylinder when acceleration is applied, it is possible to prevent the concentration of condensed water in steady running when acceleration is not applied. Even distribution of the condensed water may even be hindered by the preventing resistors (protrusions).

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to reliably prevent uneven distribution of condensed water to a specific cylinder of an engine.

In order to solve the above problems, the present invention provides an engine having a plurality of cylinders, an intake passage connected to an intake manifold of the engine, an exhaust passage connected to the exhaust manifold of the engine, and an exhaust gas recirculation device for recirculating exhaust gas from an exhaust passage side to the intake passage side; and distribution means provided in the intake passage for distributing fluid flowing in the intake passage to the plurality of cylinders. , the intake passage has an inclined portion that is inclined downward in the direction of gravity in front of a connection portion with the intake manifold, and a bent portion that is bent from the inclined portion toward the intake manifold; An intake mechanism of an engine is formed on an outer wall surface of the bent portion in the intake passage.

In the above configuration, the distribution means may be a guide groove having grooves for distributing the fluid to the plurality of cylinders.

In each of the above configurations, an inner wall surface in the intake passage facing the bent portion, which is upstream of the distribution means in the flow direction of the intake air, directs the fluid flowing along the intake passage toward the distribution means. It is possible to adopt a configuration in which projections are formed to scatter the particles.

In the configuration in which the projection is formed, the projection has a concavo-convex shape continuously formed in the width direction so as to distribute the fluid in the width direction of the outer wall surface of the distribution means. can do.

In the configuration in which the protrusions have an uneven shape, a straightening plate is provided between the successive uneven protrusions so that the fluid flowing through the intake passage is straightened along the respective protrusions. can do.

In the present invention, an intake passage that sends intake air to an engine is formed with a sloped portion that slopes downward in the direction of gravity and a bent portion that bends from the sloped portion toward the intake manifold. A configuration is adopted in which a distribution means is provided for distributing the flowing fluid to a plurality of cylinders of the engine. With this configuration, the condensed water resulting from the recirculated exhaust gas can be smoothly guided downstream by the inclined portion. Moreover, the distribution means formed in the bent portion can prevent this condensed water from being biased toward a specific cylinder, thereby maintaining a stable combustion state in the engine.

Schematic diagram showing an intake and exhaust system of an engine equipped with an intake mechanism according to the present invention. A diagram showing the main part of FIG. 1, (a) is a vertical cross-sectional view, (b) is a first example of a vertical cross-sectional view along line AA in (a), and (c) is the first example. two cases 1, (a) is a plan view, (b) is a front view, and (c) is a cross-sectional view taken along line CC in (a). 1, (a) is a plan view, (b) is a front view, and (c) is a cross-sectional view taken along line CC in (a). 1, (a) is a plan view, (b) is a front view, and (c) is a cross-sectional view taken along line CC in (a). 4 shows a fourth example of the projection of the intake mechanism according to FIG. 1, (a) is a plan view, (b) is a front view, and (c) is a cross-sectional view along line CC in (a). FIG. 2 is a longitudinal sectional view showing a modification of the intake mechanism according to FIG. 1;

After describing the overall configuration of the intake and exhaust system of an engine E having an intake mechanism according to the present invention with reference to FIGS. 1 and 2, the intake mechanism of the engine according to the present invention will be described. In this embodiment, a gasoline engine will be exemplified as the engine E, but this intake mechanism can also be applied to a diesel engine.

The engine E includes an intake passage 11 that feeds intake air into the combustion chamber 10 and an exhaust passage 12 that feeds exhaust gas from the combustion chamber 10 .

The intake passage 11 is connected upstream of an intake manifold 13 that is connected to an intake port formed integrally with the cylinder head. The exhaust passage 12 is connected downstream of an exhaust manifold 14 connected to an exhaust port integrally formed with the cylinder head. Openings of the intake port and the exhaust port to the combustion chamber 10 are opened and closed by an intake valve 15 and an exhaust valve 16, respectively.

The engine E is provided with a fuel injection device 17 that injects fuel into the intake port or the combustion chamber 10 and an ignition device 18 that generates sparks for burning the air-fuel mixture in the combustion chamber 10 . Note that the ignition device 18 is omitted in the case of a diesel engine. Although the number of cylinders of the engine E can be determined as appropriate, in this embodiment, an in-line four-cylinder engine is used.

In the intake passage 11, upstream from the intake port, a throttle valve 19 that adjusts the flow area of the intake passage 11 to control the flow rate of the intake air, an intercooler 20 that cools the intake air flowing through the intake passage 11, and an overheater. A compressor 22 of a feeder 21 (turbocharger), an air cleaner 23, and the like are provided. Further, the exhaust passage 12 is provided with a turbine 24 of the supercharger 21, an exhaust purification unit 25 for purifying exhaust gas, and the like, downstream from the exhaust port.

The supercharger 21 is arranged in the intake passage 11 and includes a compressor 22 that supercharges the intake air introduced into the combustion chamber 10 and a turbine 24 that is arranged in the exhaust passage 12 . When the turbine 24 rotates due to the exhaust gas flowing through the exhaust passage 12 , the rotation is transmitted to the compressor 22 in the intake passage 11 . The intake air flowing through the intake passage 11 is supercharged by the rotation of the compressor 22 .

The engine E includes an exhaust gas recirculation device that recirculates part of the exhaust gas in the exhaust passage 12 to the intake passage 11 as exhaust recirculation gas. In this embodiment, the exhaust gas recirculation device consists of a high pressure exhaust gas recirculation device 26 and a low pressure exhaust gas recirculation device 27 .

The high pressure exhaust gas recirculation device 26 includes a high pressure exhaust gas recirculation passage 28 connecting between the turbine 24 and the exhaust port of the exhaust passage 12 and between the intake port of the intake passage 11 and the compressor 22, and the high pressure exhaust gas recirculation passage 28. It has a high pressure exhaust gas recirculation valve 29 that opens and closes. Through this high pressure exhaust gas recirculation passage 28, relatively high pressure exhaust gas is recirculated to the intake passage 11 as exhaust gas recirculation gas. The introduction amount of the exhaust gas recirculation gas is controlled according to the pressure state in the intake passage 11 associated with the opening and closing of the high pressure exhaust gas recirculation valve 29 and the opening and closing of the throttle valve 19 .

The low-pressure exhaust gas recirculation device 27 opens and closes the low-pressure exhaust gas recirculation passage 30 connecting the downstream side of the turbine 24 in the exhaust passage 12 and the upstream side of the compressor 22 in the intake passage 11, and the low-pressure exhaust gas recirculation passage 30. A low-pressure exhaust gas recirculation valve 31 is provided. Through this low-pressure exhaust gas recirculation passage 30, relatively low-pressure exhaust gas is recirculated to the intake passage 11 as exhaust gas recirculation gas. The introduction amount of the exhaust gas recirculation gas is controlled according to the pressure state in the intake passage 11 associated with the opening and closing of the low-pressure exhaust gas recirculation valve 31 and the opening and closing of the throttle valve 32 . The low-pressure exhaust gas recirculation passage 30 is provided with a recirculation gas cooler 33 for cooling the exhaust gas recirculation gas.

In the low-pressure exhaust gas recirculation device 27, high-temperature exhaust gas is mixed with fresh air and then cooled by the intercooler 20. Therefore, depending on the mixing ratio of the exhaust gas and fresh air and the humidity of the fresh air, condensation may occur during cooling. condensed water may form. This condensed water is sent to each cylinder of the engine E through the intake passage 11 together with the intake air.

The opening and closing of the high-pressure exhaust gas recirculation valve 29 and the low-pressure exhaust gas recirculation valve 31 are electronically controlled based on the measurement results of various sensors (not shown) such as temperature sensors, pressure sensors, and gas concentration sensors provided in various parts of the intake and exhaust system. It is controlled by a control unit (not shown).

The intake mechanism of the engine E according to the present invention includes, as main components, the engine E having a plurality of cylinders, the intake passage 11, the exhaust passage 12, the exhaust gas recirculation device, and the distribution means .

In this intake mechanism, the intake passage 11 has a sloped portion 35 that slopes downward in the direction of gravity in front of a connection with the intake manifold 13 and a bent portion 36 that bends from the sloped portion 35 toward the intake manifold 13 . have. By forming the inclined portion 35 in this manner, the condensed water in the intake passage 11 can smoothly flow to the engine E side, and the intake passage 11 can be prevented from being blocked by the condensed water.

The distribution means 34 is provided in the intake passage 11 and has a function of distributing fluid flowing through the intake passage 11 to a plurality of cylinders constituting the engine E. As shown in FIG. The distribution means 34 is formed on the outer wall surface of the bent portion 36 inside the intake passage 11 . The term "fluid" as used herein mainly refers to condensed water, but is not limited to this, and includes fluid such as fresh air flowing through the intake passage 11 or a mixture of fresh air and exhaust gas.

As this distribution means 34, as shown in FIG. 3, guide grooves (hereinafter, denoted by the same reference numerals as those of the distribution means 34) formed with grooves for distributing the fluid to a plurality of cylinders can be used. For example, in the case of a four-cylinder engine, it is preferable that the guide groove shape is such that when fluid is introduced from the intake passage 11 into the intake manifold 13, the fluid is distributed in four directions toward each cylinder. As shown in FIG. 3(b), the groove depth d1 of this guide groove 34 may be uniform, but in the case of a specific cylinder (for example, a 4-cylinder engine, for example, in the case of a 4-cylinder engine), the depth d1 of the guide groove 34 may be uniform. 4 cylinder), the depths d2 and d3 of the guide groove 34 can be varied as shown in FIG. 3(c).

By providing the guide groove 34 as the distribution means 34 in this manner, the condensed water flowing through the intake passage 11 together with the intake air can be distributed to each cylinder. Therefore, condensed water can be prevented from concentrating on a specific cylinder, and a stable combustion state in the engine E can be maintained.

A protruding portion 37 is formed on an inner wall surface of the intake passage 11 that is upstream of the distribution means 34 in the direction of flow of the intake air and faces the bent portion 36 . The projecting portion 37 has a function of scattering the fluid flowing along the intake passage 11 toward the guide groove 34 . As in the above, the term "fluid" mainly refers to condensed water, but is not limited to this, and includes fluid such as fresh air flowing through the intake passage 11 or a mixture of fresh air and exhaust gas. .

As shown in FIG. 4 (first example), the projecting portion 37 may have an uneven shape continuously formed in the width direction of the outer wall surface of the guide groove 34 so as to distribute the fluid in the width direction. can. The uneven convex portion 38 has a jumping platform shape in which the upward inclination angle increases toward the tip (see FIG. 4(c)). As a result, the fluid passing through the protrusions 37 can be effectively scattered toward the guide grooves 34 . The height of the uneven protrusions 38 and the relative ratio between the width of the protrusions 38 and the adjacent protrusions 38 are merely examples, and may be changed as appropriate as long as the fluid can effectively scatter. can be done.

Further, as shown in FIG. 5 (second example), the protrusions 37 are provided between the continuous concave-convex shaped protrusions 38 to rectify the fluid flowing through the intake passage along the respective protrusions 38 . A configuration in which a plate 39 is provided can also be used. By providing the rectifying plate 39 in this way, the fluid is branched before reaching the projections 38, and the branched fluid can be more effectively scattered toward the guide grooves 34 by the projections 38. .

Further, as shown in FIG. 6 (third example), the protrusion 37 has an uneven shape continuously formed in the width direction so as to distribute the fluid in the width direction of the outer wall surface of the guide groove 34. be able to. The uneven concave portion 40 has a slide shape in which the downward inclination angle increases toward the tip (see FIG. 6(c)). As a result, the fluid passing through the protrusions 37 can be effectively scattered toward the guide grooves 34 . The amount of depression of the uneven recesses 40 and the relative ratio between the lateral width of the recesses 40 and the space between the adjacent recesses 40 are merely examples, and can be changed as appropriate as long as the fluid can be effectively scattered. .

Moreover, as the protrusion 37, as shown in FIG. 7 (fourth example), a protrusion 38 that is continuous in the width direction of the outer wall surface can be used. In this case, unlike the configuration shown in FIG. 4, the protrusion 37 does not have the action of distributing the fluid in the width direction of the outer wall surface of the guide groove 34, but it has the action of scattering the fluid toward the guide groove 34. demonstrated.

Further, as shown in FIG. 8, a storage portion 41 for temporarily storing a small amount of condensed water can be formed on the upstream side of the projection portion 37 shown in FIGS. By storing a small amount of condensed water in this manner, even when the amount of condensed water generated fluctuates, the amount of condensed water flowing from the upstream side to the downstream side of the intake passage 11 can be made constant. Therefore, a stable combustion state in the engine E can be maintained.

The intake mechanism of the engine described above is merely an example. The means 34, the shape of the protrusion 37, etc.) can be changed as appropriate.

For example, in the above description, the guide grooves 34 along the flow direction of the fluid were exemplified as the distribution means 34, but as long as the fluid can be evenly distributed to the cylinders of the engine E, the shape thereof may be changed as appropriate. can also

10 Combustion Chamber 11 Intake Passage 12 Exhaust Passage 13 Intake Manifold 14 Exhaust Manifold 15 Intake Valve 16 Exhaust Valve 17 Fuel Injector 18 Ignition Device 19 Throttle Valve 20 Intercooler 21 Supercharger 22 Compressor 23 Air Cleaner 24 Turbine 25 Exhaust Purifier 26 High Pressure Exhaust gas recirculation device 27 Low pressure exhaust gas recirculation device 28 High pressure exhaust gas recirculation passage 29 High pressure exhaust gas recirculation valve 30 Low pressure exhaust gas recirculation passage 31 Low pressure exhaust gas recirculation valve 32 Throttle valve 33 Recirculation gas cooler 34 Distribution means (guide groove)
35 Inclined portion 36 Bent portion 37 Protruding portion 38 Protruding portion 39 Straightening plate 40 Recessed portion 41 Reservoir E Engine

Claims (9)

an engine with multiple cylinders,
an intake passage connected to an intake manifold of the engine;
an exhaust passage connected to an exhaust manifold of the engine;
an exhaust gas recirculation device for recirculating exhaust gas from the exhaust passage side to the intake passage side;
a distribution means provided in the intake passage for distributing fluid flowing in the intake passage to the plurality of cylinders;
with
The exhaust gas recirculation device has a connection position where it is connected upstream of the distribution means in the intake passage,
an intercooler for cooling intake air flowing through the intake passage between the connection position and the distribution means and upstream of the distribution means;
The intake passage has an inclined portion that inclines downward in the direction of gravity in front of a connection portion with the intake manifold, and a bent portion that bends from the inclined portion toward the intake manifold, and the distribution means includes the formed on the outer wall surface of the intake passage in the bent portion,
The inclined portion is inclined downward from the inner side where the inner wall surface of the intake passage facing the bent portion is located toward the outer side where the outer wall surface is located, and the fluid flowing through the inclined portion an intake mechanism of an engine that is reversely and downwardly turned from said outer side to said inner side through the . 2. An intake mechanism for an engine according to claim 1, wherein said distribution means is a guide groove formed with grooves for distributing fluid to said plurality of cylinders. 3. A projection according to claim 1 or 2, wherein a protrusion is formed on the inner wall surface upstream of the distribution means in the direction of intake air flow, for scattering the fluid flowing along the intake passage toward the distribution means. Intake mechanism of the described engine. 4. An intake mechanism for an engine according to claim 3, wherein said projecting portion has a concavo-convex shape continuously formed in said width direction so as to distribute the fluid in said outer wall surface of said distribution means in said width direction. 5. An intake mechanism for an engine according to claim 4, wherein a rectifying plate is provided between each of said continuous projections of uneven shape for rectifying the fluid flowing through said intake passage so as to follow each of said projections. an engine with multiple cylinders,
an intake passage connected to an intake manifold of the engine;
an exhaust passage connected to an exhaust manifold of the engine;
an exhaust gas recirculation device for recirculating exhaust gas from the exhaust passage side to the intake passage side;
a distribution means provided in the intake passage for distributing fluid flowing in the intake passage to the plurality of cylinders;
with
The intake passage has an inclined portion that inclines downward in the direction of gravity in front of a connection portion with the intake manifold, and a bent portion that bends from the inclined portion toward the intake manifold, and the distribution means includes the formed on the outer wall surface of the intake passage in the bent portion,
A projecting portion for scattering the fluid flowing along the intake passage toward the distributing portion is provided on an inner wall surface of the intake passage that is upstream of the distributing portion in the intake air flow direction and faces the bent portion. The intake mechanism of the engine being formed. 7. The engine intake mechanism according to claim 6, wherein said distribution means is a guide groove formed with a groove for distributing fluid to said plurality of cylinders. 8. An intake mechanism for an engine according to claim 6, wherein said projecting portion has a concavo-convex shape continuously formed in said width direction so as to distribute the fluid in said outer wall surface of said distribution means in said width direction. . 9. An intake mechanism for an engine according to claim 8, wherein a rectifying plate is provided between each of said continuous projections of uneven shape for rectifying the fluid flowing through said intake passage so as to follow each of said projections.

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