JP2023078741A - Intake structure of engine - Google Patents

Abstract

To provide an intake structure of an engine capable of more reliably suppressing vibration of an intake passage.SOLUTION: A throttle valve body is connected to an upper end of an intake manifold, and when a direction parallel to a horizontal direction and along one side surface of an engine body is a lateral direction, the intake manifold curves and extends from the throttle valve body toward one side in the lateral direction and downward. An EGR passage includes a vertical pipe portion extending in a vertical direction and having an upper end connected to a surface on the other side in the lateral direction in an upper portion of the intake manifold, and a connection portion for connecting a lower end of the vertical pipe portion with a lower exhaust passage.SELECTED DRAWING: Figure 4

Description

The present invention comprises an engine body, an intake passage connected to an intake port opening on one side of the engine body and through which intake air introduced into the engine body flows, an exhaust passage through which exhaust gas discharged from the engine body flows, The present invention relates to an intake structure of an engine including an EGR passage that communicates an intake passage and an exhaust passage and recirculates EGR gas, which is a part of exhaust gas, to the intake passage.

As a conventional engine intake structure, for example, Patent Document 1 discloses that a throttle valve body including a throttle valve capable of changing the flow path area of intake air and a drive device for driving the throttle valve is provided in an intake passage. A structure is disclosed in which the throttle valve body is supported by an EGR tube in order to suppress vibrations in the intake passage around the throttle valve body.

Specifically, in the structure of Patent Document 1, an intake manifold (intake manifold in Patent Document 1) is connected to an engine body (cylinder head in Patent Document 1) so as to extend upward from the engine body, and the intake manifold A throttle valve body is connected to the upstream end of the throttle valve body so as to be horizontally aligned therewith. An EGR tube is connected to the upstream end of the intake manifold, and the EGR tube extends downward from the upstream end of the intake manifold and is fixed to the engine body.

JP-A-11-141406

In the structure of Patent Document 1, the EGR tube supports most of the weight of the throttle valve body. Therefore, it is necessary to increase the rigidity of the EGR tube in order to suppress the vibration of the throttle valve body and the vibration of the intake passage. In other words, in the structure of Patent Document 1, if the EGR tube does not have sufficiently high rigidity, the effect of suppressing the vibration of the intake passage is limited. Thus, the structure of Patent Document 1 has room for improvement in terms of more reliably suppressing the vibration of the intake passage.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an intake structure for an engine that can more reliably suppress vibration of an intake passage.

In order to solve the above problems, the present invention provides an engine body, an intake passage connected to an intake port opening on one side of the engine body and through which intake air introduced into the engine body flows, and the engine. An intake structure for an engine comprising: an exhaust passage through which exhaust gas discharged from a main body flows; and an EGR passage that communicates between the intake passage and the exhaust passage and recirculates EGR gas, which is a part of exhaust gas, to the intake passage. , the intake passage includes an intake manifold extending upward from the opening of the intake port along one side surface of the engine body and having a downstream end of the EGR passage connected to an upper portion thereof; and an intake manifold disposed upstream of the intake manifold. a throttle valve body including a throttle valve capable of changing the flow path area of the intake air and a drive device for driving the throttle valve, wherein the exhaust passage is disposed below the intake manifold; The throttle valve body is provided with a passage, and is connected to the upper end of the intake manifold. The EGR passage has a shape extending downward from the throttle valve body while curving in one of the horizontal directions. and a connecting portion connecting the lower end portion of the vertical pipe portion and the lower exhaust passage (Claim 1).

According to the present invention, the throttle valve body is connected to the upper end of the intake manifold. Therefore, the throttle valve body can be stably supported by the intake manifold. Further, the intake manifold has a shape extending from the throttle valve body while curving downward in one lateral direction, and the EGR passage is connected to the upper portion of the intake manifold. Therefore, compared to the case where the intake manifold extends straight downward from the throttle valve body, the length of the flow path for EGR gas and intake air is secured without increasing the vertical dimension of the intake manifold, promoting mixing of these gases. can do.

Moreover, in the present invention, the EGR passage is connected to the lower exhaust passage provided below the intake manifold at the connecting portion, and extends vertically so that the upper end portion is on the other lateral side of the upper portion of the intake manifold. It has a vertical pipe section connected to the plane. Therefore, vertical vibration of the upper portion of the intake manifold can be suppressed. Specifically, in the present invention, the throttle valve body is connected to the upper end of the intake manifold which exhibits a shape extending while curving downward in one lateral direction, so that the intake manifold is positioned on the other lateral side of the intake manifold. It becomes easy for the upper part of it to be displaced in the up-down direction. On the other hand, since the vertical pipe portion restricts the displacement of the upper portion on the other side in the horizontal direction of the intake manifold, the vibration of the upper portion is suppressed.

As described above, according to the present invention, it is possible to reduce the vertical dimension of the intake manifold, promote mixing of EGR gas and intake air, and more reliably suppress vibration of the throttle valve body and the intake passage.

In the above configuration, preferably, the vertical tube portion includes an EGR fixing portion fixed to the engine body (Claim 2).

According to this configuration, the vertical pipe portion is stably supported by the engine body via the EGR fixing portion. Therefore, the vibration of the intake manifold and the intake passage supported by the vertical pipe portion can be more reliably suppressed.

In the above configuration, preferably, the height position of the EGR fixing portion is lower than the height position of the lower end of the intake manifold (Claim 3).

According to this configuration, it is possible to effectively suppress the vertical displacement of the entire intake manifold, that is, the vertical vibration of the entire intake manifold and the vibration of the intake passage.

In the above configuration, preferably, the EGR fixing portion is provided at a position overlapping with the throttle valve body in the lateral direction (Claim 4).

According to this configuration, the throttle valve body can be stably supported on the engine body via the vertical pipe portion and the EGR fixing portion.

In the above configuration, preferably, the vertical pipe portion includes an EGR valve body including an EGR valve capable of changing the flow path area of the EGR gas and an EGR valve drive device for driving the EGR valve (claim 5). .

According to this configuration, the rigidity of the vertical pipe portion can be increased to suppress the displacement of the vertical pipe portion and thus the displacement of the intake passage, and the vibration of the intake passage can be suppressed more reliably.

Here, when the intake manifold is made of resin, it is more likely to be displaced than when it is made of metal. Therefore, it is effective to apply the present invention to an intake passage in which the intake manifold is made of resin (claim 6).

Further, the engine body may be a rotary piston engine (claim 7).

As described above, according to the engine intake structure of the present invention, the vibration of the intake passage can be suppressed more reliably.

1 is a system diagram showing a schematic configuration of an engine according to an embodiment of the invention; FIG. It is a schematic side view of the engine as seen from the right. FIG. 3 is a schematic side view corresponding to FIG. 2 and showing details of components of the intake and exhaust system; FIG. 3 is a schematic side view of the engine as seen from the rear;

(Overall structure of the engine)
FIG. 1 is a system diagram showing a schematic configuration of an engine to which an engine intake structure according to an embodiment of the invention is applied.

An engine 1 according to this embodiment is mounted on a vehicle. For example, the engine 1 is installed in a hybrid vehicle that includes a motor as a power source for running, a battery that supplies power to the motor, and a generator that charges the battery, and is used as a device that generates power for the generator. The engine 1 includes an engine main body 10, an intake passage 3 through which intake air introduced into the engine main body 10 flows, an exhaust passage 8 through which exhaust gas discharged from the engine main body 10 flows, and an exhaust passage 8 and intake air. An EGR passage 6 that communicates with the passage 3 and recirculates EGR gas, which is a part of exhaust gas, from the exhaust passage 8 to the intake passage 3 is provided.

(engine body)
The engine body 10 of the present embodiment is a one-rotor type rotary piston engine (hereinafter referred to as a rotary engine), and includes one rotor 11 that rotates around a predetermined rotation axis and an eccentric It has a shaft 12 , a rotor housing 13 having an inner peripheral surface along a two-node peritrochoid curve, and a pair of side housings 14 , 14 sandwiching the rotor housing 13 in the direction along the rotation axis of the rotor 11 . The rotor 11 is housed in a rotor housing chamber R partitioned by a rotor housing 13 and two side housings 14 , 14 , and rotates along the inner peripheral surface of the rotor housing 13 while planetarily rotating with respect to the eccentric shaft 12 . Rotate.

The engine body 10 also has a rear holder 20 that is connected to a portion of one side housing 14 opposite to the rotor housing 13 (in the direction along the rotation axis of the rotor 11) and to which a flywheel 21 is fixed. An oil pan 22 is attached to the lower portion of the engine body 10 .

The engine body 10 is mounted on the vehicle in such a posture that the rotating shaft of the rotor 11 and the eccentric shaft 12 extend substantially horizontally (a direction substantially perpendicular to the vertical direction). Hereinafter, as shown in FIG. 2 and the like, the direction along the rotation axis of the rotor 11, that is, the longitudinal direction of the eccentric shaft 12 is referred to as the front-rear direction. do. In the description of the engine 1, the up-down direction when the engine 1 is mounted on the vehicle is simply referred to as the up-down direction, and the left-right direction when the engine body 10 is viewed from the rear is simply referred to as the left-right direction. Note that the engine body 10 in FIG. 1 is a schematic cross-sectional view when viewed from the front. Here, in this embodiment, the vertical direction, that is, the vertical direction when the engine 1 is mounted on the vehicle, corresponds to the "vertical direction" in the claims, and the front-rear direction, that is, the longitudinal direction of the eccentric shaft 12 corresponds to the "vertical direction" in the claims. corresponds to "horizontal direction".

The engine main body 10 includes an intake port 15 connected to the intake passage 3 to introduce the intake air in the intake passage 3 into the rotor housing chamber R, and an exhaust passage 8 connected to the exhaust passage 8 for introducing the exhaust gas from the rotor housing chamber R. An exhaust port 16 is formed leading to the . The intake port 15 opens to the upper right side of the rotor housing chamber R, and the exhaust port 16 opens to the lower right side of the rotor housing chamber R. As shown in FIG. That is, in the engine body 10, the rotor 11 rotates clockwise when viewed from the front, and the upper right, upper left, lower left, and lower right regions of the rotor housing chamber R generally undergo an intake stroke, a compression stroke, and an expansion stroke, respectively. , and exhaust stroke.

Two intake ports 15 and two exhaust ports 16 are provided in the engine body 10 . The engine body 10 is a side port type rotary engine, and an intake port 15 and an exhaust port 16 are formed in a side housing 14 . That is, one intake port 15 is formed in each upper portion of the two side housings 14 , and each intake port 15 opens in the upper portion of the right side surface of each side housing 14 . Also, one exhaust port 16 is formed in each of the lower portions of the two side housings 14 , and each exhaust port 16 opens in the lower portion of the right side surface of each side housing 14 .

A fuel injection device 17 for injecting fuel into the rotor housing chamber R and a spark plug 18 for adding a mixture of fuel and air formed in the rotor housing chamber R are attached to the engine body 10 . In this embodiment, the fuel injection device 17 is mounted so as to face the upper end of the rotor housing chamber R, and the spark plug 18 is mounted so as to face the lower left portion of the rotor housing chamber R.

(intake passage)
The intake passage 3 is provided with an air cleaner 31A for removing foreign substances contained in the intake air, and a throttle valve capable of adjusting the amount of intake air introduced into the engine body 10 by changing the flow area of the intake air passing through the intake passage 3. 41 are provided in this order from the upstream side.

Specifically, the intake passage 3 includes a first intake passage 31, a second intake passage 32, a throttle valve body 40, and an intake manifold 50 arranged in order from the upstream side. The air cleaner 31 A is provided in the first intake passage 31 and the throttle valve 41 is provided in the throttle valve body 40 . In addition to the throttle valve 41 , the throttle valve body 40 has a throttle valve case 42 that surrounds the throttle valve 41 to define a passage through which intake air passes, and an actuator 43 that drives the throttle valve 41 . The throttle valve 41 is driven by an actuator 43 to open and close a passage defined by a throttle valve case 42 . In this embodiment, the actuator 43 that drives the throttle valve 41 is a motor, and the actuator 43 is hereinafter referred to as the throttle valve motor 43 . The throttle valve motor 43 corresponds to the "driving device" in the claims.

A portion of the first intake passage 31 downstream of the air cleaner 31A is provided with an air flow meter sensor SN1 for detecting the flow rate of intake air passing through that portion. The intake manifold 50 is provided with an intake air temperature sensor SN2 for detecting the intake air temperature, which is the temperature of the gas passing through it.

A downstream end of an intake manifold 50 is connected to each of the intake ports 15, 15, and intake air (air) flowing into the first intake passage 31 passes through the air cleaner 31A, the second intake passage 32, the throttle valve case 42 and the intake. It is introduced into the rotor housing chamber R through the manifold 50 and the intake ports 15 , 15 .

(exhaust passage)
The exhaust passage 8 is provided with a purification device 81 for purifying exhaust gas. The exhaust passage 8 has an exhaust manifold 82 communicating with each of the exhaust ports 16 , 16 , and the purification device 81 is arranged downstream of the exhaust manifold 82 .

(EGR passage)
The EGR passage 6 communicates the exhaust manifold 82 and the intake manifold 50 . The EGR passage 6 includes an EGR cooler 62 that cools the EGR gas, and an EGR valve 71 that can adjust the amount of EGR gas introduced into the intake passage 3 by changing the flow area of the EGR gas passing through the EGR passage 6. and are provided.

Specifically, the EGR passage 6 includes a first EGR passage 61, an EGR cooler 62, a second EGR passage 63, an EGR valve body 70, and a third EGR passage 64 arranged in order from the exhaust passage 8 side. The EGR valve 71 is provided in the EGR valve body 70 . The exhaust manifold 82 is connected to the upstream end of the first EGR passage 61 (in the EGR gas flow direction), and the intake manifold 50 is connected to the downstream end of the third EGR passage 64 (in the EGR gas flow direction). there is

In addition to the EGR valve 71 , the EGR valve body 70 has an EGR valve case 72 that surrounds the EGR valve 71 and defines a passage through which EGR gas passes, and an actuator 73 that drives the EGR valve 71 . The EGR valve 71 is driven by an actuator 73 to open and close a passage defined by the EGR valve case 72 . In this embodiment, the actuator 73 that drives the EGR valve 71 is a motor, and the actuator 73 is hereinafter referred to as the EGR valve motor 73 . The EGR valve motor 73 corresponds to the "EGR valve driving device" in the claims.

(detailed structure)
2 and 3 are schematic side views of the engine 1 viewed from the right. In FIG. 2 , each housing and the like of the engine body 10 are indicated by dashed lines, and illustration of bolts and the like is omitted. In FIG. 3, illustration of each housing of the engine body 10 is omitted, but bolts and the like are shown. FIG. 4 is a schematic side view of the engine 1 as seen from the rear.

As described above, each intake port 15 opens to the upper portion of the right side surface of each side housing 14, that is, the upper portion of the right side surface 10A of the engine body 10, and each exhaust port 16 opens to the right side of each side housing 14. The bottom of the surface, that is, the bottom of the right side surface 10A of the engine body 10 is opened. The right side surface 10A of the engine body 10 in which the intake ports 15 are opened to form these openings corresponds to "one side surface of the engine body" in the claims.

The exhaust manifold 82 communicating with each of the exhaust ports 16 , 16 is arranged on the right side of the engine body 10 . The exhaust manifold 82 has a shape extending in the front-rear direction. The exhaust manifold 82 is fixed to the lower portion of the right side surface 10A of the engine body 10 via an exhaust manifold fixing portion 120 so as to communicate with the two exhaust ports 16,16. The exhaust manifold 82 corresponds to the "lower exhaust passage" in the claims.

A portion of the intake passage 3 on the downstream side of the throttle valve body 40 is arranged on the right side of the engine body 10 . The intake manifold 50 extends upward along the right side surface 10A of the engine main body 10 from the openings of the intake ports 15, 15 on the right side surface 10A of the engine main body 10. As shown in FIG. The intake manifold 50 extends to a position above the engine body 10 . A lower portion of the intake manifold 50 has a shape extending in the front-rear direction and communicates with the two intake ports 15 , 15 .

The intake manifold 50 has a forwardly convex shape extending forward (one side in the front-rear direction) and downward from its upper end while curving. Further, the intake manifold 50 has a shape in which the upper end is shifted rearward from the lower end. In this embodiment, the intake manifold 50 is made of resin.

An intake manifold fixed portion 110 that is fixed to the right side surface 10A of the engine body 10 is provided below the intake manifold 50 . The intake manifold 50 is fixed to the engine body 10 by fixing the intake manifold fixed portion 110 to the right side surface 10A of the engine body 10 with bolts 112 .

Specifically, one intake manifold fixed portion 110 is provided at each of the four corners of the lower portion of the intake manifold 50 . As shown in FIG. 4, the upper right side of the engine body 10 is inclined so that the lower side is located on the right side, and the right side surface 10A of the engine body 10 constitutes the upper side and is inclined to the right side as it is lowered. It is composed of an inclined surface 210A inclined so as to be positioned and a vertical surface 220A extending substantially straight downward from the lower edge of the inclined surface 210A. The four intake manifold fixed portions 110 each have a plate shape along the inclined surface 210A, and are fixed to the inclined surface 210A by bolts 112, respectively.

The throttle valve body 40 is connected to the upper end of the intake manifold 50 at a position above the engine body 10 .

Specifically, the throttle valve case 42 has a substantially cylindrical shape extending in a predetermined direction. The throttle valve motor 43 has a substantially cylindrical outer shape extending in a predetermined direction and is fixed to the outer surface of the throttle valve case 42 . The throttle valve body 40 is connected to the upper end of the intake manifold 50 with the throttle valve case 42 extending upward from the upper end of the intake manifold 50 and the throttle valve motor 43 extending in the left-right direction behind the throttle valve case 42 . ing. As shown in FIG. 4, the throttle valve body 40 is connected to the upper end of the intake manifold 50 with the throttle valve motor 43 protruding leftward from the left edge of the throttle valve case 42 when viewed from the rear. . In this embodiment, the throttle valve case 42 is made of metal.

The EGR passage 6 is arranged on the right side of the engine body 10 . The EGR passage 6 is roughly divided into a vertical pipe portion 65 extending downward from the rear surface of the upper portion of the intake manifold 50 and a connecting portion 66 extending forward from the lower end of the vertical pipe portion 65 and connected to the exhaust manifold 82 . It is The vertical pipe portion 65 is arranged behind the intake manifold 50 , the connecting portion 66 is arranged between the intake manifold 50 and the exhaust manifold 82 , and the EGR passage 6 is located above the intake manifold 50 as a whole. It extends from the rear surface to the upper surface of the front portion of the exhaust manifold 82 through the area behind the intake manifold 50 and between the intake manifold 50 and the exhaust manifold 82 . The vertical pipe portion 65 includes the third EGR passage 64 , the EGR valve body 70 and the second EGR passage 63 , and the connecting portion 66 includes the EGR cooler 62 and the first EGR passage 61 .

Specifically, an EGR passage connecting portion 59 that protrudes rearward is provided on the rear surface of the upper end portion of the intake manifold 50 . The downstream end of the third EGR passage 64, that is, the downstream end of the EGR passage 6, is connected to this EGR passage connecting portion 59, that is, the surface of the upper portion of the intake manifold 50 on the rear side (the side opposite to the convex side of the intake manifold in the longitudinal direction). there is The third EGR passage 64 extends downward from the EGR passage connecting portion 59 . Specifically, the upper portion of the third EGR passage 64 is curved downward from the rear surface of the EGR passage connection portion 59 so as to protrude rearward. The lower portion of the third EGR passage 64 extends substantially straight downward from the lower end of the upper portion of the third EGR passage 64 below the EGR passage connecting portion 59 .

The EGR valve body 70 is arranged to the right of the third EGR passage 64 . The EGR valve case 72 has a substantially cylindrical shape extending in a predetermined direction. The EGR valve motor 73 has a substantially cylindrical outer shape extending in a predetermined direction and is fixed to the outer surface of the EGR valve case 72 . The EGR valve body 70 is disposed on the right side of the third EGR passage 64 with the EGR valve case 72 extending vertically and the EGR valve motor 73 extending upward from the upper end of the EGR valve case 72 . The third EGR passage 64 is connected to the left side surface of the EGR valve case 72 and extends upward from the left side surface of the EGR valve case 72 through between the EGR valve motor 73 and the right side surface 10A of the engine body 10. .

The second EGR passage 63 is connected to the lower surface of the EGR valve case 72 . The second EGR passage 63 extends obliquely forward and downward from the lower surface of the EGR valve case 72 .

A flange portion 140 is integrally formed with the second EGR passage 63 . The flange portion 140 has a substantially triangular plate shape (when viewed from the right side) extending downward from the second EGR passage 63 . An EGR fixing portion 141 for fixing the second EGR passage 63 and the EGR passage 6 to the right side surface 10A of the engine body 10 is provided at the lower end of the flange portion 140 .

The EGR fixing portion 141 is fixed to the right side surface 10A of the engine body 10 with bolts 142 . EGR fixing portion 141 is fixed to the upper portion of vertical surface 220A of right side surface 10A of engine body 10 . That is, in this embodiment, the vertical pipe portion 65 has an EGR fixing portion 141 at its lower end, and the vertical pipe portion 65 and the EGR passage 6 are fixed to the engine body 10 via this EGR fixing portion 141. ing.

The lower end positions of the second EGR passage 63 and the flange portion 140 are below the lower end position of the intake manifold 50, and the height position (vertical position) of the EGR fixing portion 141 is the height of the lower end of the intake manifold 50. It is lower than the position (vertical position). Further, as shown in FIG. 3, the EGR fixing portion 141 is positioned immediately below the throttle valve body 40 in a side view (viewed from the right side), and overlaps the throttle valve body 40 in the front-rear direction. is placed in That is, the EGR fixing portion 141 is provided in a region from the front end position to the rear end position of the throttle valve body 40 in the front-rear direction. A dashed line L1 in FIG. 3 is a vertical line passing through the center of gravity of the throttle valve body 40 . In this embodiment, as shown in FIG. 3 , the EGR fixing portion 141 is provided on a vertical line passing through the center of gravity of the throttle valve body 40 when viewed from the side (when viewed from the right). In addition, in this embodiment, as shown in FIG. 4, the EGR fixing portion 141 is positioned directly below the throttle valve body 40 even when viewed from the rear (viewed from the rear), and is positioned directly below the throttle valve body 40 in the left-right direction as well. 40 and is disposed at a position overlapping. That is, in the present embodiment, the EGR fixing portion 141 is arranged at a position overlapping the throttle valve body 40 when viewed from above (when viewed from above).

The EGR cooler 62 has a substantially rectangular parallelepiped shape. The EGR cooler 62 is disposed below the intake manifold 50 and above the exhaust manifold 82 so as to extend forward from the front end of the second EGR passage 63 . More specifically, the EGR cooler 62 is disposed between the intake manifold 50 and the exhaust manifold 82 in a tilted posture so that the front side is positioned downward. The EGR cooler 62 is fixed to the right side surface 10A of the engine body 10 via an EGR cooler fixed portion 130 extending downward from the lower surface of the EGR cooler 62 . The EGR cooler 62 cools the EGR gas with a cooling liquid, and the EGR cooler 62 is connected to pipes 62A and 62B for introducing and discharging cooling water flowing through the EGR cooler 62 .

The first EGR passage 61 extends forward from the front end of the EGR cooler 62 . Specifically, the first EGR passage 61 is inclined downward toward the front. The front end of the first EGR passage 61 curves downward and is connected to the upper surface of the front end portion of the exhaust manifold 82 . That is, the first EGR passage 61 extends upward and obliquely rearward from the upper surface of the front end portion of the exhaust manifold 82 .

Here, in this embodiment, the first EGR passage 61, the EGR cooler 62, the second EGR passage 63, the EGR valve case 72 and the third EGR passage 64 are all made of metal.

(action, etc.)
As described above, in the above embodiment, the throttle valve body 40 including the throttle valve motor 43 is connected to the upper end of the intake manifold 50 . Therefore, the throttle valve body 40 can be stably supported by the intake manifold 50 .

Here, if the intake manifold 50 has a shape that extends straight in the vertical direction and the flow path length is secured, and the throttle valve body 40 is simply arranged above the intake manifold 50, these parts of the intake passage 3 The vertical dimension of the area occupied by is excessively large. In contrast, in the above-described embodiment, the intake manifold 50 has a shape extending forward and downward from its upper end, that is, from the throttle valve body 40 while curving. Therefore, while suppressing the vertical dimension of the region occupied by the intake manifold 50 and the throttle valve body 40 from becoming excessive, the above-described configuration of arranging the throttle valve body 40 above the intake manifold 50 is realized. The passage length of the manifold 50 can be ensured. In the above embodiment, since the EGR passage 6 is connected to the upper portion of the intake manifold 50, the passage length of the intake manifold 50 is ensured, so that the EGR gas introduced to the upper portion of the intake manifold 50 is supplied to the engine. It can be sufficiently mixed with intake air before reaching the main body 10 .

However, as described above, the intake manifold 50 exhibits a shape that curves forward and downward, and the throttle valve body 40 is connected to the upper end of the intake manifold 50, so that the upper part of the intake manifold 50, more specifically, , the portion of the intake manifold 50 located in the rear upper region is easily displaced in the vertical direction as indicated by the arrow Y1 in FIG. In particular, in the above-described embodiment, the intake manifold 50 is made of resin, and is easily displaced.

In contrast, in the above embodiment, the EGR passage 6 is connected to the exhaust manifold 82 provided below the intake manifold 50 . The downstream end of the EGR passage 6 is connected to the upper rear surface of the intake manifold 50, and the EGR passage 6 extends downward from this connecting portion. Specifically, the upper end portion of the vertical pipe portion 65 of the EGR passage 6, which includes the third EGR passage 64, the EGR valve body 70, and the second EGR passage 63 and extends in the vertical direction, is provided on the rear surface of the upper portion of the intake manifold 50. It is connected to the passage connecting portion 59 and extends downward from the EGR passage connecting portion 59 . That is, the EGR passage 6 whose displacement is restricted by the exhaust manifold 82 is arranged to extend downward from the upper rear surface of the intake manifold 50 . Therefore, the EGR passage 6 can restrict the vertical displacement of the upper portion of the intake manifold 50, that is, the portion of the intake manifold 50 located in the rear upper region. Therefore, according to the above-described embodiment, the vertical vibration of the intake manifold 50 and thus the vibration of the intake passage 3 can be more reliably suppressed while obtaining the above effects.

In particular, in the above embodiment, the second EGR passage 63 and the vertical pipe portion 65 including the second EGR passage 63 are supported by the engine body 10 via the EGR fixing portion 141 in addition to the exhaust manifold 82 . Therefore, the vertical pipe portion 65 can be stably supported by the engine body 10 . Therefore, the vibration of the intake manifold 50 and the intake passage 3 supported by the vertical pipe portion 65 can be suppressed more reliably.

Further, in the above embodiment, the height position of the EGR fixing portion 141 is set lower than the height position of the lower end of the intake manifold 50 . Therefore, vertical pipe portion 65 can effectively suppress vertical displacement and vibration of intake manifold 50 as a whole, and vibration of the intake passage.

Further, in the above-described embodiment, the EGR fixing portion 141 is provided at a position overlapping the throttle valve body 40 in the front-rear direction. Therefore, the throttle valve body 40 can be stably supported by the engine body 10 via the vertical pipe portion 65 and the EGR fixing portion 141 .

Further, in the above embodiment, the EGR valve body 70 including the EGR valve 71 and the EGR valve motor 73 forms part of the vertical pipe portion 65 . That is, the EGR valve body 70 is provided in the vertical pipe portion 65 . Therefore, the rigidity of the vertical pipe portion 65 can be increased, and displacement and vibration of the vertical pipe portion 65 and thus the intake manifold 50 and the intake passage 3 can be suppressed more reliably.

(Modification)
In the above embodiment, the case where the engine body 10 is a rotary piston engine has been described, but the type of the engine body 10 is not limited to this.

Although the case where the intake manifold 50 is made of resin has been described in the above embodiment, the material of the intake manifold 50 is not limited to this.

3 intake passage 6 EGR passage 8 exhaust passage 10 engine body 15 intake port 16 exhaust port 40 throttle valve body 41 throttle valve 42 throttle valve case 43 throttle valve motor (driving device)
50 Intake manifold 65 Vertical pipe portion 66 Connection portion 70 EGR valve body 71 EGR valve 73 EGR valve motor (EGR valve driving device)
82 Exhaust manifold (lower exhaust passage)
141 EGR fixing part

Claims (7)

an engine main body, an intake passage connected to an intake port opening on one side of the engine main body and through which intake air introduced into the engine main body flows, an exhaust passage through which exhaust gas discharged from the engine main body flows, An intake structure for an engine comprising an EGR passage that communicates between an intake passage and an exhaust passage to recirculate EGR gas, which is a part of exhaust gas, to the intake passage,
The intake passage includes an intake manifold extending upward from an opening of the intake port along one side surface of the engine body and having a downstream end of the EGR passage connected to an upper portion thereof, and an intake manifold disposed upstream of the intake manifold. a throttle valve body including a throttle valve capable of changing the flow path area of the intake air and a drive device for driving the throttle valve,
The exhaust passage includes a lower exhaust passage arranged below the intake manifold,
The throttle valve body is connected to the upper end of the intake manifold,
When a direction parallel to the horizontal direction and along the one side surface of the engine body is defined as a lateral direction, the intake manifold has a shape extending downward from the throttle valve body while curving in one of the lateral directions. death,
The EGR passage includes a vertical pipe portion extending in the vertical direction and having an upper end connected to a surface of the upper portion of the intake manifold on the other side in the horizontal direction, a lower end portion of the vertical pipe portion, and the lower exhaust passage. An intake structure for an engine, comprising: a connecting portion that connects the In the intake structure of the engine according to claim 1,
The intake structure for an engine, wherein the vertical pipe portion includes an EGR fixing portion fixed to the engine body. In the intake structure of the engine according to claim 2,
An intake structure for an engine, wherein the height position of the EGR fixing portion is lower than the height position of the lower end of the intake manifold. In the engine intake structure according to claim 2 or 3,
The intake structure for an engine, wherein the EGR fixing portion is provided at a position overlapping with the throttle valve body in the lateral direction. In the engine intake structure according to any one of claims 1 to 4,
An intake structure for an engine, wherein the vertical pipe portion includes an EGR valve body including an EGR valve capable of changing a flow path area of the EGR gas and an EGR valve driving device for driving the EGR valve. In the engine intake structure according to any one of claims 1 to 5,
The intake structure for an engine, wherein the intake manifold is made of resin. In the engine intake structure according to any one of claims 1 to 6,
An intake structure for an engine, wherein the engine body is a rotary piston engine.

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