JPH0220426Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an exhaust port structure for a rotary piston engine, in which an exhaust port is opened on the inner peripheral surface of a rotor housing having a trochoidal inner peripheral surface.

(Prior Art) A rotary piston engine generally includes a rotor housing having a trochoidal inner circumferential surface in which a rotor is rotatably housed, and side housings attached to both sides of the rotor housing. It forms a rotor chamber. The rotor chamber has an apex seal portion between the inner peripheral surface of the rotor housing at the corner vertices of the regular polygonal rotor, thereby defining a plurality of working chambers. The housing is formed with one or more intake ports and one exhaust port opening into the working chamber. The exhaust port of a conventional rotary piston engine is
Only one approximately elliptical hole with a long axis in the direction of the rotor rotational axis is formed on the inner peripheral surface of the trochoid of the rotor housing, and this port is opened when the apex seal portion of the rotor passes through. It's becoming like that. Since this exhaust port has a long axis in the direction of the rotational axis of the rotor, the opening area of the exhaust port increases rapidly when the apex seal portion passes through the exhaust port. For this reason, a problem arises in that a large amount of exhaust gas concentrates at the exhaust port, creating a turbulent flow and rapidly expanding, producing high exhaust noise. In order to solve this problem, a so-called honeycomb structure has been proposed in which the exhaust port is composed of a set of three circular ports, two on the leading side and one on the trailing side. -Refer to Publication No. 148621). Although this structure is effective to some extent in reducing exhaust noise, it has the drawback of increasing exhaust passage resistance.

To address the issue of exhaust noise and exhaust resistance,
It has been proposed that a port insert including a cylindrical outer cylinder that includes a horizontal partition plate that partitions an exhaust port in the circumferential direction of the rotor housing, that is, in the longitudinal direction of the exhaust port, is inserted into the exhaust passage portion of the rotor housing. According to this proposal, among the exhaust branch passages divided by the horizontal partition plate, the trailing side branch passage is further divided into small sections by the vertical partition plate, and the exhaust air immediately after the opening of the exhaust port is divided into smaller sections by the vertical partition plate. By dispersing energy and preventing turbulence in the exhaust air, we aim to reduce noise, and by placing partition plates only on the trailing side of the port, we minimize the increase in passage resistance. , to obtain the effect of reducing exhaust noise.
However, since the exhaust passage portion of the rotor housing into which the port insert is inserted is adjacent to the rotor chamber, the port insert is exposed to a considerably high temperature. In this case, the cylindrical outer cylinder of the port insert is surrounded by the rotor housing, so the temperature is not that high, around 500°C, but on the other hand, the partition plate installed inside is always exposed to high temperatures. Approximately 900% due to contact with exhaust gas
It reaches temperatures of around 1000°C. There is a large temperature difference between the cylindrical outer cylinder and the partition plate of the port insert during use, so if the binding force between the two is strong, large thermal stress will occur, causing deformation or cracking. may occur.

(Purpose of the present invention) Therefore, the purpose of the present invention is to provide an exhaust port for a rotary piston engine that can fully perform its functions without any hindrance and effectively reduce exhaust noise even if a large temperature difference occurs. It's about providing structure.

(Structure of the present invention) In order to achieve the above object, the present invention is structured as follows. That is, the present invention defines an exhaust port opening in the inner circumferential surface of the rotor housing in the circumferential direction of the rotor housing, and also includes a horizontal partition plate extending in the flow direction of the exhaust gas and a cylindrical outer cylinder surrounding the horizontal partition plate. an exhaust port structure for a rotary piston engine, including a port insert inserted in the exhaust flow direction into an exhaust passage portion formed in a rotor housing, one end of which is connected to the horizontal partition plate; A vertical partition plate is provided, which extends in a direction perpendicular to the rotor and toward the trailing side in the rotational direction of the rotor, and whose other end is fixed to the cylindrical outer cylinder, and the horizontal partition plate is connected to the cylindrical outer cylinder at a joint portion thereof. It is characterized by not having.

Therefore, in the present invention, since the horizontal partition plate provided in the port insert is not connected to the cylindrical outer cylinder, there is a temperature difference between the horizontal partition plate and the cylindrical outer cylinder during use. However, no thermal stress acts between the two. Note that in the use state, the horizontal partition plate has a higher temperature, so that the partition plate has a larger amount of thermal expansion. Therefore, it is necessary to provide a predetermined gap between the horizontal partition plate and the cylindrical outer cylinder in consideration of the amount of thermal expansion of the partition plate. However, if this gap is too large, it will have a negative effect on the exhaust noise reduction effect, so it is desirable that this gap is 1.5 mm or less.

(Effects of the present invention) In the present invention, the horizontal partition plate is connected to the cylindrical outer cylinder through the vertical partition plate, and a large temperature difference occurs between the horizontal partition plate and the cylindrical outer cylinder. If a difference occurs in the amount of thermal expansion, there is a clearance between the tube and the cylindrical outer cylinder that can absorb this amount of expansion, so no thermal stress is applied. Therefore, according to the present invention, occurrence of thermal deformation or cracking can be prevented, and an exhaust port structure with improved durability can be obtained. Note that the clearance is set as small as possible within a range that can absorb the difference in thermal expansion due to the temperature difference between the partition plate and the cylindrical outer cylinder, and does not weaken the exhaust noise reduction effect.

(Embodiment) FIG. 1 shows a side port intake type rotary piston engine Z having an exhaust port structure according to an embodiment of the present invention. This rotary piston engine Z includes a rotor housing 1 having a trochoidal inner circumferential surface 4 and a pair of side housings that seal both sides of the rotor housing 1, thereby forming a rotor chamber 10 inside. Rotor chamber 1
A substantially triangular rotor 3 is disposed inside the rotor 3, and a rotor housing 1 is attached to the rotor 3.
It has an apex portion 30 having an apex seal that is in sliding contact with the inner circumferential surface 4 of the. As a result, working chambers 27a, 27b, and 27c are formed by the rotor housing 1 and the side surface of the rotor 3, respectively. The rotor 3 is supported by an eccentric shaft 5 and rotates in the direction indicated by the arrow in FIG. As the rotor 3 rotates, the volumes of the working chambers 27a, 27b, and 27c change periodically, thereby forming intake, compression, explosion, and exhaust strokes.
In FIG. 1, the state shown in the working chamber 27a is at the end of the explosion stroke and at the beginning of the exhaust stroke.
The working chamber 27b is in the intake stroke, and the working chamber 27c is in the compression stroke. The side housing 2 is provided with an intake port 6 that opens into the working chamber 27b during the intake stroke, and is adapted to introduce the air-fuel mixture into the working chamber 27b. The rotor housing 1 is provided with an exhaust port 7.
During the exhaust stroke, combustion gas is exhausted from the working chamber 27a.

Referring to FIG. 2, the exhaust port 7 is provided with a through hole 9 provided in the rotor housing 1, and the through hole 9 opens into the rotor chamber 10 through a mouth edge 7a. At the same time, it passes through the rotor housing 1 in the thickness direction. The through hole 9 includes a seat hole portion 9a extending inward from the outer surface 1b of the rotor housing, an inclined hole portion 9b extending further inward from the seat hole portion 9a, and a seat hole portion 9b closest to the inner circumferential surface 4. Parallel hole part 9c
It is composed of. Referring to FIG. 4, the mouth edge 7a has a rectangular shape with curved corners. The parallel hole portion 9c of the through hole 9 has substantially the same shape as the mouth edge portion 7a. The inclined hole portion 9b is
At the inner end, that is, on the side of the rotor chamber 10, the width of the rotor 3 in the direction of the rotation axis is slightly larger than the mouth edge 7a, and the length in the direction perpendicular to the width is as follows.
It is larger than the mouth edge 7a, thereby forming a step S1 on the trailing side and a step S2 on the leading side. The slanted hole portion 9b is expanded outward on its leading side, so that its cross-sectional area increases outwardly. The seat hole portion 9a is larger in both width and length than the outer end of the inclined hole portion 9b, thereby forming a stepped portion S3 around the periphery. As shown in FIG. 2, a port insert 8 is adapted to be inserted into the through hole 9. Referring to FIG. 3, the port insert 8 has a seat hole portion 9a and an inclined hole portion 9b.
It is provided with a flange part 11 that can be seated on a stepped part S3 formed between. This port insert 8 is formed with an inclined cylindrical portion 12 extending from a collar portion 11 . The inclined cylinder portion 12 has a shape corresponding to the inclined hole portion 9b of the through hole 9. In this case, the inclined cylinder portion 12 is configured such that a clearance G exists between it and the inclined hole portion 9b. Inside the port insert 8, there is provided a horizontal partition plate 16 that extends in the width direction of the insert, that is, in the horizontal direction. (exhaust passage) and a trailing side exhaust passage 21. The port insert 8 further has one end connected to the horizontal partition plate, extends in the vertical direction that divides the trailing side exhaust passage 21, that is, in a direction perpendicular to the direction in which the horizontal partition plate 16 extends, and has an inclined other end. A pair of vertical partition plates 17 connected to the trailing side of the cylindrical portion 12 are provided. As a result, the trailing side exhaust passage 21 has three subdivisions, namely, the second exhaust branch passage 2
2. Third exhaust branch passage 23 and fourth exhaust branch passage 24
It is divided into. The fourth exhaust branch passage 24 is formed between the two vertical partition plates 17, and the second and third exhaust branch passages 22, 23 are connected to the fourth exhaust branch passage 2.
4 are formed at opposing positions on both sides. The horizontal partition plate 16 and the vertical partition plate 17 extend outward from the inner end of the collar portion 11, that is, in the exhaust gas outflow direction, and extend inward along the inclined cylinder portion 12, and further,
It protrudes from the inner end of the inclined cylindrical portion 12 and reaches the mouth edge 7a of the through hole 9. And the tip 16a,
17a reaches a position extremely close to the inner circumferential surface 4 of the rotor housing 1. Further, the rear ends 16b, 17 of the horizontal partition plate 16 and the vertical partition plate 17
b is located inward from the rear end of the port insert 8, that is, deeper into the inner circumferential surface 4 side, and therefore, the horizontal partition plate 16 and the vertical partition plate 17 are cut out on the downstream side in the exhaust gas outflow direction. It's taking shape.

The trailing side of the inclined cylindrical portion 12 extends inward from the tip 12a, that is, toward the inner peripheral surface 4, and is bent toward the leading side at the tip, and partially extends between the pair of vertical partition plates 17. A covering screen plate 15 is formed. This limits the entrance area of the fourth exhaust passage 24. Therefore, the trailing side open end 24a of the fourth exhaust branch passage 24 is closer to the screen plate 1 than the trailing side open ends 22a, 23a of the second and third exhaust branch passages 22, 23.
It is located on the leading side by the length of the rotor housing No. 5 in the circumferential direction.

In addition, the end with the horizontal partition plate 16 and the inclined cylinder part 1
2, a certain clearance G1 is provided in the width direction, and even if the horizontal partition plate 16 expands due to the temperature difference between the inclined cylinder part and the horizontal partition plate 16 during use, the It is designed to absorb the amount of expansion.

Next, the operation of the rotary piston engine Z of the illustrated embodiment will be explained. When the engine Z is operated, the rotor 3 slides the apex portions 30 attached to the three ridges onto the trochoid inner circumferential surface 4. The rotor 3 rotates planetarily around the eccentric shaft 5, and during one rotation of the rotor 3, intake air is sucked into the working chamber from the intake port 6, pressurized, and then combusted and exploded, and the combustion gas (exhaust gas) is sent to the exhaust port 7. discharge from.

Incidentally, as the rotor 3 rotates, the apex portion 30 passes through the exhaust port 7 from the trailing side to the leading side, and the exhaust port 7 is connected to the trailing side working chamber of the apex portion 30 (in FIGS. 1 and 2). 27a), the high pressure and high temperature exhaust gas in the trailing side working chamber 27a is discharged to the outside from the opened exhaust port 7 through the exhaust passage.

In this case, in this embodiment, the exhaust port 7
Leading side exhaust passage (first exhaust branch passage) 2
The trailing side exhaust passage 21 is further divided into three parts in the width direction of the rotor housing 1 to form a second exhaust passage 21 and a trailing side exhaust passage 21.
Since the third and fourth exhaust branch passages 22, 23, and 24 are used, even immediately after the opening where the exhaust gas pressure is particularly high (exhaust energy is large), the exhaust gas is transferred to the small volume second, third, and 4 exhaust passages 22, 23,
24, the rapid expansion of the exhaust gas is prevented and the exhaust energy of the exhaust gas is dispersed.The horizontal partition plate 16 and the vertical partition plate 17 act as a type of rectifying plate, and the exhaust gas flow is is rectified. Therefore, the vibration noise is reduced and the exhaust noise of the engine Z is reduced.

Partition plates 16 and 17 of port insert 8 in this example
is brought into direct contact with the high-temperature exhaust gas discharged from the rotor chamber 3 at a position close to the rotor chamber 3, and therefore rises to approximately 900°C to 1000°C.
On the other hand, the flange part 11 and the inclined cylinder part 12 of the port insert 8 also come into contact with the exhaust gas, but the rotor housing 1 is arranged around them, and the heat energy from the exhaust gas is taken away by the rotor housing 1. The temperature is not that high, staying around 500℃. Therefore, the horizontal partition plate 16 and the inclined cylinder part 12
A temperature difference occurs between the horizontal partition plate 16 and the horizontal partition plate 12, which causes the horizontal partition plate to expand relatively greatly. No thermal stress occurs. Therefore, problems such as thermal deformation and clutching do not occur.

Note that the structure of the horizontal partition plate 16 does not necessarily have to extend continuously in the width direction, and as shown in FIG. 5, it can be provided only on both sides in the width direction. Even in this case, by providing the clearance G1 in the width direction, the same effect as that of the port insert 8 described in connection with FIGS. 1 to 4 can be obtained.

In addition, this exhaust port 7 partitions the exhaust passage by a thin horizontal partition plate 16 and a vertical partition plate 17, and especially on the trailing side,
Because it has a unique structure, the passage area decreases less than the conventional honeycomb port type exhaust port structure, and therefore the exhaust port 7
When the exhaust gas is fully opened, a sufficient passage area can be secured, and problems such as a decrease in engine output due to an increase in exhaust resistance can be prevented from occurring.

Next, the relationship between the noise reduction effect and the clearance G1 will be described.

In this case, as shown in FIG. 2A, the angle formed between the surface of the screen plate 15 on the working chamber 27a side and the above straight line _l1 , that is, the screen plate inclination angle θ, and the surface of the screen plate 15 on the working chamber 27a side. and the surface forming the working chamber 27a, and the distance B from the trailing side of the exhaust port 7 to the top of the screen plate 15 are defined, respectively. Change the clearance G1 appropriately,
We tested the relationship with changes in noise level.

Test conditions Engine speed: 3000 rpm Engine load condition: Full load (load condition where the engine speed is 3000 rpm with the throttle valve fully open) Port timing Intake port open Eccentric shaft angular position 75° before BDC Intake port closed Eccentric shaft angular position TDC Rear 48° In this example, B = 5 mm, A = 2.5 mm,
Therefore, B/A=2. Further, the screen plate inclination angle θ is 59°. Figure 6 shows the results. According to this result, a high noise reduction effect appears when the clearance G1 is 1.5 mm or less.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a rotary piston engine according to the present invention, FIG. 2 is a partially enlarged sectional view of the vicinity of the exhaust port of the rotary piston engine of FIG. 1, and FIG. 2A is a sectional view showing the structure of the screen plate. 3 is a perspective view of a port insert according to the present invention, FIG. 4 is a view taken along the - arrow in FIG. 2, and FIG. 5 is a sectional view showing another structure of the port insert, and FIG. is the noise level and clearance G
1 is a graph showing the relationship with 1. 1... Rotor housing, 2... Side housing, 3... Rotor, 4... Trochoid inner peripheral surface,
6...Intake port, 7...Exhaust port, 8...Port insert, 9...Through hole, 10...Rotor chamber, 16...Horizontal partition plate, 17...Vertical partition plate.

Claims (1)

[Scope of utility model registration request] The rotor housing has a horizontal partition plate that defines an exhaust port opening in the inner circumferential surface of the rotor housing in the circumferential direction of the rotor housing, and extends in the flow direction of the exhaust gas, and a cylindrical outer cylinder that encompasses the horizontal partition plate. An exhaust port structure for a rotary piston engine including a port insert inserted in the exhaust flow direction into the formed exhaust passage portion,
a vertical partition plate having one end connected to the horizontal partition plate, extending in a direction perpendicular to the horizontal partition plate and toward the trailing side in the rotor rotational direction, and having the other end fixed to the cylindrical outer cylinder; The horizontal partition plate is
An exhaust port structure for a rotary piston engine, characterized in that it does not have a joint portion with the cylindrical outer cylinder.