JPH04121453U - Exhaust recirculation device for multi-cylinder engines - Google Patents

Abstract

(57) [Summary] [Purpose] To remove the engine without increasing the overall length of the engine.
Allows installation of air reflux valve. [Configuration] Adjacent exhaust ports in cylinder head 3
7₂,7₃widen the spacing towards their exits and
Formed on one side of the cylinder head 3 in the area sandwiched between the outlets
The return flow path 24 and the exhaust are attached to the return flow path block mounting surface 13.
The reflux path block 15 having the air reflux valve 31 is joined, and this
The reflux path block 15 is connected to the exhaust port 7. ₂,7₃connected to
Two branch exhaust pipes 22 of the exhaust manifold 9 to pass through₂，
22₃Place it in between.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention aims to reduce the generation of NOx due to excessive rise in combustion temperature in multi-cylinder engines. Exhaust recirculation device to suppress air pollution, especially for communication between engine exhaust system and intake system The exhaust gas recirculation valve is equipped with a recirculation path and an exhaust gas recirculation valve that controls the flow rate of exhaust gas in the recirculation path. Regarding improvements.

0002

[Conventional technology]

Conventionally, in such exhaust recirculation devices, the exhaust recirculation valve was placed on the cylinder head side of the engine. It is known to be installed on the outer part of the intake manifold that is joined to the surface (for example, (See Japanese Patent Publication No. 154259/1983).

0003

[Problem that the idea aims to solve]

By the way, if you install the exhaust recirculation valve on the outside of the intake manifold as shown above, , the overall length of the engine is increased by the exhaust recirculation valve, and in automobiles, the narrow engine This may make it difficult to fit the engine into the engine compartment, and may also cause leakage from the exhaust port. The recirculation path up to the exhaust recirculation valve is relatively long and has many bends, so it is important to reduce the amount of exhaust recirculation. In some cases, it may not be possible to control accurately as required.

0004 This invention was devised in view of the above circumstances, and it is possible to increase the overall length of the engine by almost all the time. Exhaust recirculation that allows the installation of an exhaust recirculation valve without causing any damage and can be controlled with high precision. Our aim is to provide an exhaust recirculation system for multi-cylinder engines that also makes it possible to expand the range. target

[0005]

[Means to solve the problem]

In order to achieve the above objective, the present invention provides a Of the multiple exhaust ports to be opened, two adjacent exhaust ports are The area is formed to expand toward the one side, and is sandwiched between these two exhaust ports. A return flow block mounting surface is formed on the one side in the area, and a return flow block mounting surface is formed on the above-mentioned one side. opens an exhaust branch port branched from at least one of the two exhaust ports. At the same time, there is a recirculation passage connected to this exhaust branch port and a recirculation passage having an exhaust recirculation valve. The block is joined to the exhaust manifold which is joined to the one side of the recirculation path block. This is placed between the two branch exhaust pipes corresponding to the two exhaust ports of the The first feature is

[0006] In addition to the above-mentioned features, this invention also features an air intake that is joined to the other side of the cylinder head. curving the manifold and arranging its upstream end above the return flow path block; A second feature is that the reflux path is connected to the upstream end via a reflux conduit.

[0007] Furthermore, in addition to the first or second feature, the present invention provides a cooling chamber in the exhaust gas recirculation valve. The third feature is that this cooling chamber is connected to two parts of the intake system where a pressure difference occurs. shall be.

[0008]

【Example】

An embodiment of the present invention will be described below with reference to the drawings.

First, in FIG. 1, the engine E is configured in a V-shape with a left bank Bl and a right bank Br protruding from a common crankcase 1 in a V-shape. Each bank Bl, Br includes a cylinder block 2 that is integrally cast with a crankcase 1, and a cylinder head 3 that is joined to the upper end surface of this cylinder block 2. Four cylinders 5 ₁ to 5 ₄ (see FIG. 3) are formed in parallel in the direction, and the cylinder head 3 has four intake ports 6 ₁ to 6 ₄ connected to the cylinders 5 ₁ to 5 ₄ , respectively. and exhaust ports 7 ₁ to 7 ₄ are formed.

The intake ports 6 ₁ to 6 ₄ open on the inner surface of the cylinder head 3 facing the cylinder head of the other bank, and the exhaust ports 7 ₁ to 7 ₄ open on the outer surface opposite to the inner surface. Open to. On the inner surface of the cylinder head 3, there is an intake manifold 8 for introducing intake air into the intake ports ₆₁ to ₆₄ , and on the outer surface, there is an exhaust manifold 9 for guiding exhaust air from the exhaust ports ₇₁ to ₇₄ . are respectively joined.

[0011] The intake manifold 8 is bent so as to bypass the upper part of the corresponding cylinder head 3. It curves and extends so that its upstream end reaches the outer surface side of the cylinder head 3. A throttle body 11 equipped with a throttle valve 10 is connected to the upstream end of the throttle body 11 . This slot An air cleaner (not shown) is connected to the inlet of the throttle body 11 via an intake pipe 29. be done.

0012 Further, an exhaust gas recirculation device R is attached to the outer surface of the cylinder head 3.

[0013] Intake manifold 8, exhaust manifold 9, exhaust return for left and right banks Bl and Br Since the flow device R has the same structure, the details below are representative of the one on the right bank Br side. Explain.

As shown in FIGS. 2 and 3, among the four exhaust ports 6 ₁ to 6 ₄ , the two adjacent inner exhaust ports 6 ₂ and 6 ₃ are spaced apart from each other on the outside of the cylinder head 3. The exhaust ports 6 ₂ , 6 3 are formed to widen toward the sides, so that the outlet centers of the exhaust ports 6 2 , 6 ₃ are offset outwardly by e from the centers of the corresponding cylinders 5 ₂ , 5 ₃ , respectively. As shown in FIG. 4, a pair of exhaust manifolds are provided on the outer surface of the cylinder head 3 in areas surrounding the openings of two adjacent outer exhaust ports 6 ₁ , 6 ₂ ; 6 ₃ , 6 ₄ . A return passage block mounting surface 13 is formed in the area sandwiched between the mounting surfaces _{12 1 and 12 2 ,} and two inner intake ports ₆ 2 are formed on this return passage block mounting surface 13 . , 6 ₃ , an exhaust branch port 14 is opened.

A pair of mounting flanges 17 ₁ , 17 ₂ of the exhaust manifold 9 are connected to the exhaust manifold mounting surfaces 12 ₁ , 12 ₂ with bolts 19 via a gasket 18 , and the return flow path block mounting surface 13 has a return flow path. Blocks 15 are joined with bolts 21 via gaskets 20.

The exhaust manifold 9 includes four branch exhaust pipes 22 ₁ to 22 ₄ communicating with the exhaust ports 7 ₁ to 7 ₄ , respectively, and a merging chamber body connected to the downstream ends of these branch exhaust pipes 22 ₁ to 22 ₄ . The pair of mounting flanges 17 ₁ , 17 ₂ are formed at the upstream ends of the two outer branch exhaust pipes 22 ₁ , 22 ₂ ; 22 ₃ , 22 ₄ , and the two inner branch exhaust pipes 22 1 , 22 2 ; The reflux path block 15 is arranged between the pipes 22 ₂ and 22 ₄ . 2 and 3 again, the reflux passage block 15 is formed with a reflux passage 24 that communicates with the exhaust branch port 14, and its downstream end is connected to the reflux passage 26 of the intake manifold 8 via a reflux conduit 25. communicate with.

The intake manifold 8 includes four branch intake pipes 27 1 to 27 ₄ communicating with the intake ports _{6 1} to 6 ₄ , respectively, and a distribution chamber body 28 connected to the upstream side of these branch intake pipes. The throttle body 11 is connected to this distribution chamber body 28. The recirculation passage 26 of the intake manifold 8 is provided so as to run vertically along the bottom wall of the distribution chamber body 28 and communicate with the four branched intake passages 27 ₁ to 27 ₄ via supply holes 30 , 30 .

[0018] On the upper surface of the recirculation path block 15, there is an exhaust recirculation that controls the exhaust gas flow rate in the recirculation path 24. A flow valve 31 is attached. This exhaust gas recirculation valve 31 is located on the upper surface of the recirculation path block 15. It includes a valve box 32 to be joined and an actuating part 33 provided on the upper part of the valve box 32. A valve body 34 that controls opening and closing of the reflux passage 24 is housed therein. Housing of actuating part 33 35, a diaphragm 36 connects an upper negative pressure chamber 37 and a lower atmospheric chamber 38 (this invention (corresponding to the cooling chamber), and the valve body 34 is connected to the diaphragm 36 thereof. The spring 39 that biases the valve body 34 in the valve closing direction via the diaphragm 36 becomes negative. It is contracted into the pressure chamber 37.

[0019] The negative pressure chamber 37 is connected to the intake manifold 8 via a negative pressure conduit 40 as shown in FIG. or the negative pressure outlet pipe 41 of the throttle body 11, and the negative pressure conduit 40 is connected to the negative pressure outlet pipe 41. A magnetic valve 42 is provided. This solenoid valve 42 conducts the negative pressure conduit 40 when energized, and disconnects it. When electricity is supplied, the negative pressure conduit 40 is disconnected and the negative pressure chamber 37 is opened to the atmosphere. Ru. Therefore, by controlling the energization time of the solenoid valve 42, the negative pressure in the negative pressure chamber 37 is reduced. The opening degree of the valve body 34 can be controlled by adjusting the size of the valve body 34.

Similarly, as shown in FIG. 1, the solenoid valves 42, 42 of the left and right banks Bl, Br are driven by a common control device 43, and this control device 43 receives a rotation speed signal of the engine E. Ne, water temperature signal Tw, boost negative pressure signal P _B , oxygen concentration signal O ₂ in exhaust gas, opening degree signal V _R of exhaust gas recirculation valve 31, etc. are given as input signals.

[0021] Referring again to FIG. 2, the housing 35 has an atmospheric chamber 38 on one side and the other side, respectively. An inlet pipe 44 and an outlet pipe 45 are provided which are open. Also, the throttle body The intake pipe 29 connected to the inlet of 11 has openings at its upstream and downstream parts, respectively. An air take-off pipe 46 and an air return pipe 47 are attached, and this air take-off pipe 46 and the air return pipe 47 are connected to each other. Air tubes 48 and 49 are connected between the inlet pipe 44, the air return pipe 47, and the outlet pipe 45, respectively. are connected to each other via.

[0022] The air take-out pipe 46 has an upper part to facilitate taking out the intake air flowing inside the intake pipe 29. The inner end of the air return pipe 47 is oriented toward the flow side, and the air return pipe 47 is The inner end is oriented downstream to encourage air to return from the intake pipe 29 to the intake pipe 29.

[0023] Next, the operation of this embodiment will be explained.

[0024] During operation of engine E, the exhaust port 7 inside from its combustion chamber₃Exhaust gas discharged into A part of the gas is reliably diverted to the exhaust branch port 14 with its dynamic pressure, and , the reflux conduit 25 and the reflux path 26, and the intake manifold through the supply holes 30, 30... Branch intake pipe 27 of field 8₁~27_FourThese branch intake pipes 27₁~2 7_FourCylinder 5 of engine E along with the intake air flowing through₁~5_Fouris inhaled. child During this period, in the recirculation path block 15, the exhaust gas flowing through the recirculation path 24 passes through the exhaust recirculation valve 3. 1, the flow rate is controlled to correspond to the operating state of the engine E, so each cylinder 5 ₁ ~5_FourExcessive rise in combustion temperature is suppressed, preventing or reducing the generation of NOx. It can be suppressed. Moreover, the dynamic pressure of the exhaust gas flow acts on the exhaust branch port 14. and the length of the passage from the inlet of the port 14 to the exhaust recirculation valve 31 is relatively short. As a result, a large amount of exhaust gas can be taken into the exhaust gas recirculation valve 31. Exhaust recirculation region where the amount of exhaust gas recirculated to the intake system can be controlled with high precision by operating the flow valve 31 can be expanded, especially toward the increase side.

[0025] On the other hand, a part of the intake air flowing into the intake pipe 29 from an air cleaner (not shown) is The air is taken out by the air take-off pipe 46 and exhausted through the air tube 48 and the inlet pipe 44. After flowing into the atmospheric chamber 38 of the reflux valve 31 and ventilating the chamber 38, the outlet pipe 45 and the air It returns to the intake pipe 29 through the tube 49 and the air return pipe 47, and returns to the intake pipe 29 along with other intake air. It is sucked into the throttle body 11. In this way, the atmospheric chamber of the exhaust recirculation valve 31 38 is always ventilated with intake air while the engine E is operating, so the exhaust recirculation valve 3 1 can be effectively cooled from the inside, especially the valve body 34 and the diaphragm 36. This can contribute to improving the durability of

By the way, in the exhaust gas recirculation device R, the recirculation path block 15 in which the exhaust gas recirculation valve 31 is installed is sandwiched between adjacent exhaust ports 7 ₂ and 7 ₃ that are spaced apart from each other toward the outer surface of the cylinder block 2. _{The above - mentioned} By expanding the space between the branch exhaust pipes 22 ₂ and 22 ₃ , this space can be effectively used for installing the recirculation path block 15 and the exhaust recirculation valve 31, so that the increase in the overall length of the engine E due to the exhaust recirculation valve 31 is almost negligible. do not have. Moreover, since the recirculation path block 15 is separated from the exhaust manifold 9, the exhaust recirculation valve 31 is not easily affected by the heat of a large amount of exhaust gas flowing through the exhaust manifold 9.

[0027] Furthermore, the distribution chamber body 28 of the intake manifold 8 bypasses the upper part of the cylinder head 3. Since the flow reaches the reflux path block 15 side, it is formed on the bottom wall of the distribution chamber body 28. The reflux passage 26 can be brought sufficiently close to the reflux passage 24 of the reflux passage block 15, Therefore, the reflux conduit 25 connecting between the two reflux paths 24 and 26 should be made as short as possible to improve the piping. Simplification can be achieved.

In the present invention, the two adjacent outer exhaust ports 7 ₁ , 7 ₂ or 7 ₃ , 7 ₄ are formed so that the distance between them increases toward the outer surface of the cylinder head 3. The recirculation passage block 15 may be joined to the outer surface of the cylinder head 3 in a region sandwiched between the exhaust ports 7 ₁ , 7 ₂ or 7 ₃ , 7 ₄ .

[0029]

[Effect of the idea]

As described above, according to the first feature of the present invention, one side of the cylinder head of the engine Of the multiple exhaust ports that open on the surface, connect two adjacent exhaust ports between them. The gap is formed so that it widens toward the one side, and is sandwiched between these two exhaust ports. A return flow block mounting surface is formed on the one side in the area where the return flow block is mounted. The surface has an exhaust branch port branched from at least one of the two exhaust ports. A recirculation valve is opened and has a recirculation path and an exhaust recirculation valve that are connected to this exhaust branch port. A flow passage block is joined, and this return flow passage block is attached to an exhaust master joined to the one side. Place it between the two branch exhaust pipes of the Nifold that correspond to the two exhaust ports mentioned above. Therefore, there is a dead space between the two adjacent branch exhaust pipes of the exhaust manifold. It is possible to install a recirculation path block and an exhaust recirculation valve using the There is almost no increase in the overall length of the engine due to the exhaust recirculation valve, so it allows for a narrow engine room. The engine can be easily stored. Moreover, the exhaust gas is connected to the exhaust branch port. The dynamic pressure of the flow acts, and the passage length from the inlet of the port to the exhaust recirculation valve is The relatively short length allows a large amount of exhaust gas to be taken into the exhaust recirculation valve. Therefore, the amount of exhaust gas recirculated to the intake system can be controlled with high precision by operating the exhaust gas recirculation valve. It is possible to expand the exhaust gas recirculation region toward the increase side.

[0030] Further, according to the second feature of the present invention, the intake air joined to the other side of the cylinder head curving the manifold and arranging its upstream end above the return flow path block; Since the reflux path is connected to the upstream end via the reflux conduit, the reflux conduit can be kept as short as possible. As a result, the piping can be simplified.

[0031] Furthermore, according to a third feature of the present invention, a cooling chamber is provided in the exhaust gas recirculation valve, and the cooling chamber is provided in the exhaust gas recirculation valve. Since the cooling chamber is connected to two parts of the intake system where a pressure difference occurs, the intake air flow of the intake system can be used. can cool the exhaust recirculation valve and increase its durability, thus reducing the Even if the recirculation path block is connected to a high-temperature area called a pad, the exhaust recirculation valve will always function normally. can be made to function.

[Brief explanation of drawings]

[Fig. 1] Front view of a multi-cylinder engine that is an embodiment of the present invention

[Figure 2] Enlarged vertical cross-sectional view of the main part of Figure 1

[Figure 3] Cross-sectional view taken along line 3-3 in Figure 2

[Figure 4] Cross-sectional view taken along line 4-4 in Figure 2

[Explanation of symbols]

3 Cylinder head 5 ₁ to 5 ₄ cylinders 6 ₁ to 6 ₄ intake ports 7 ₁ to 7 ₄ exhaust ports 8 Intake manifold 9 Exhaust manifold 12 ₁ , 12 ₂ Exhaust manifold mounting surface 13 Recirculation path block mounting surface 14 Exhaust branch port 15 Reflux Path block 22 ₁ to 22 ₄ -branch exhaust pipe 23 Merging chamber body 24 Reflux path 25 Reflux conduit 27 ₁ to 27 _4- branch intake pipe 28 Distribution chamber body 29 Intake pipe 30 Supply hole 31 Exhaust recirculation valve 34 Valve element 36 Diaphragm 37 Negative pressure Chamber 38 Atmospheric chamber 44 Inlet pipe 45 Outlet pipe 46 Air take-out pipe 47 Air return pipes 48, 49 Air tube E Engine R Exhaust recirculation device

Claims (3)

[Scope of utility model registration request] 1. A recirculation path (24) that communicates between an exhaust system and an intake system of an engine (E), and an exhaust recirculation valve (31) that controls the flow rate of exhaust gas in this recirculation path (24). In an engine exhaust gas _{recirculation system, two adjacent exhaust ports (7 2 , 7 3} ) are formed such that the interval between them widens toward the one side, and these two exhaust ports (7 ₂ ,
A return passage block mounting surface ( ₁₃ ) is formed on the one side in the area sandwiched by the return passage block mounting surface (13).
3), an exhaust branch port (14) branched from at least one of the two exhaust ports (7 ₂ , 7 ₃ ) is opened, and a reflux path (24) and a reflux path (24) connected to the exhaust branch port (14) are opened. A recirculation path block (15) having an exhaust gas recirculation valve (31) is joined to the recirculation path block (15).
an exhaust manifold (9) joined to said one side;
2 corresponding to the two exhaust ports (7 ₂ , 7 ₃ ) of
An exhaust gas recirculation device for a multi-cylinder engine, characterized in that it is disposed between two branch exhaust pipes (22 ₂ , 22 ₃ ). 2. In the apparatus according to claim 1, the intake manifold (8) joined to the other side of the cylinder head (3) is curved and its upstream end is disposed above the recirculation passage block (15). and the reflux path (2) is provided at the upstream end.
4) is connected via a recirculation conduit (25). [Claim 3] The product according to claim 1 or 2,
A cooling chamber (38) is provided in the exhaust gas recirculation valve (31), and this cooling chamber (38) is divided into two parts (4) where a pressure difference in the intake system occurs.
6,47) An exhaust gas recirculation device for a multi-cylinder engine.