JPS62157231A - Exhauster for rotary piston engine - Google Patents

Abstract

PURPOSE:To make exhaust noise and vibration reducible, by interconnecting an exhaust starting period operating chamber on one side to an exhaust middle period operating chamber on the other of a pair of trochoidal spaces via an interconnecting passage before a blow-down phenomenon of exhaust gas occurs. CONSTITUTION:A pair of trochoidal spaces 10 and 11 to be adjoined to each other as holding an intermediate housing 6 in between makes an exhaust starting period operating chamber on one side and an exhaust middle period operating chamber on the other get interconnected to each other at the specified timing before a blow-down phenomenon of exhaust gas occurs via an interconnecting passage 12. Therefore, at an exhaust starting period, a part of high temperature and high pressure exhaust gas inside the exhaust starting period operating chamber flows into the exhaust middle period operating chamber side via the interconnecting passage 12, so that the blow-down phenomenon of the exhaust gas in a part of an exhaust port 15 or 16 is restrained from occurrng. Thus, exhaust noise and vibration as well as exhaust resistance are all reduced and, what is more, suction charging efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an exhaust system for a rotary piston engine, particularly a multi-cylinder rotary piston engine.

(Prior Art) Generally, in a rotary piston engine, exhaust ports opened on the trochoid inner peripheral surface of the rotor housing are sequentially opened and closed by each top of the rotor as the rotor rotates. In this case, especially when the engine is operating at high speed and high load, high temperature and high pressure may be exhausted from the working chamber in the initial state of exhaust immediately after opening the exhaust boat. ()A(jll, m count nil r
z4 :(di I-nA middle 1 f t#ill
/-Y It is known that a so-called blowdown phenomenon occurs in which the exhaust gas pressure within the IW suddenly increases (see Fig. 7). When a blowdown phenomenon occurs immediately after the exhaust port opens, (1) High temperature gas suddenly blows out from the working chamber toward the exhaust passage.
(2) High-pressure exhaust gas collides with relatively low-temperature, low-pressure exhaust gas remaining in the exhaust passage and generates shock waves, causing large exhaust noise and vibrations or an increase in exhaust resistance. During the opening of the exhaust passage (in other words, the apex seal of the rotor neck is located directly above the exhaust port, and the operation occurs at the end of the exhaust stroke on the leading side of the exhaust port in the rotational direction of the rotor (in other words, just before the start of the intake stroke) During the period when the chamber and the working chamber on the trailing side are temporarily communicating through the exhaust port immediately after the start of the exhaust stroke, high-temperature, high-pressure exhaust gas suddenly ejects into the exhaust passage due to the blowdown phenomenon. A phenomenon occurs when the exhaust gas flows into the working chamber facing the start of the intake stroke through the exhaust passage, and problems such as a decrease in the filling efficiency of the intake air into the suction side working chamber occur. It will occur.

Therefore, in order to reduce exhaust noise, vibration, and exhaust resistance in rotary piston engines, it is necessary to take some effective means to prevent the blowdown phenomenon immediately after the exhaust port is opened. Therefore, the present applicant has developed and already proposed an exhaust structure as disclosed in Japanese Patent Publication No. 46-6642 as a specific means for efficiently suppressing the occurrence of the blowdown phenomenon.

By the way, in this known exhaust structure, the exhaust ports, which were conventionally configured as a single opening, are appropriately spaced apart in the axial direction (thickness direction) of the rotor housing and at predetermined intervals in the circumferential direction. It consists of three small openings that are lined up in stages in a sequentially retracted state, and the three small openings are opened in stages as the rotor rotates. This is to prevent high-pressure exhaust gas from suddenly blowing out toward the exhaust port as much as possible.

However, when the exhaust port is configured with a plurality of small openings that are sequentially formed in stages in the circumferential direction of the rotor housing, the occurrence of the blowdown phenomenon immediately after the exhaust port is opened can be suppressed. On the other hand, (+) Since the opening length of the exhaust port in the circumferential direction of the rotor housing is longer than that of the conventional structure,
For example, the period of communication between the working chamber located on the trailing side of the exhaust port in the rotor rotational direction and the working chamber located on the leading side of the exhaust port becomes longer, and as a result, the blowdown phenomenon is suppressed. (2) The opening length in the circumferential direction of the rotor housing of the tJI air boat is longer than that of the conventional structure. Compared to other systems, it is inevitable that a configuration must be chosen between opening the exhaust port earlier or closing it later.As a result, for example, a configuration that advances the opening timing is adopted. In this case, the expanded exhaust gas will be discharged from the exhaust port, which will increase the energy loss.On the other hand, if a configuration is adopted that delays the timing of the blockage, the amount of exhaust gas will be discharged from the exhaust port. There was room for improvement in terms of iso-intake filling efficiency and thermal efficiency, which could increase.

(Objective of the Invention) In view of the problems pointed out in the prior art section above, the present invention reduces exhaust noise, vibration, and exhaust resistance by reducing as much as possible the occurrence of the blowdown phenomenon immediately after opening the exhaust port. The purpose of this invention is to provide an exhaust system for a rotary piston engine that is designed to reduce the amount of exhaust gas as much as possible and to improve the filling efficiency of intake air.

(Means for Achieving the Object) As a means for achieving the above object, the present invention provides an intermediate housing, a rotor housing disposed on both sides of the intermediate housing, and an engine mounted on the side of the rotor housing. The rotor has a side housing disposed at the end thereof, and a substantially triangular rotor is supported by an eccentric link shaft and rotates planetarily through the trochoid space formed by the intermediate housing or the side housing and the rotor housing. In a cylinder rotary piston engine, the exhaust stroke start period n:i is determined among the working chambers included in the trochoid spaces of 1χ, t that are adjacent to each other across the intermediate housing.
An exhaust start period working chamber on one side of the trochoid space which is in the start period of the exhaust stroke spanning a predetermined stroke period after the start of the exhaust stroke, and an exhaust middle period working chamber on the other trochoid space side which is in the middle or latter half of the exhaust stroke. A communication path is provided in the intermediate housing to communicate the exhaust gas at a predetermined timing before the exhaust gas blowdown phenomenon occurs in the exhaust boat part on the trochoid space side where the exhaust start working chamber is located. It is.

(For A) In the present invention, by the above-mentioned means, the exhaust start working chamber of one trochoid space of a pair of adjacent trochoid spaces and the exhaust M working chamber of the other trochoid space are connected to each other during exhaust gas blowing. Since they are communicated with each other via the communication passage at a predetermined timing before the down phenomenon occurs, a portion of the high-temperature, high-pressure exhaust gas in the working chamber at the start of exhaust gas flows through the communication passage and becomes relatively exhaust gas. When the pressure peak becomes low, it flows out to the exhaust middle working chamber side on the other trochoid space side, and as a result, the exhaust start stage working chamber side! This means that the occurrence of the blow-down phenomenon of exhaust gas in the J1 air boat section is suppressed as effectively as possible.

(Technical Background of the Invention) In the process of researching a method for effectively suppressing the occurrence of the blowdown phenomenon of exhaust gas when the exhaust port is opened, the inventors of the present invention discovered the structural features of a multi-cylinder rotary piston engine. That is, between a pair of adjacent engine units of a multi-cylinder rotary piston engine formed by axially arranging a plurality of engine units, the rotors of each engine unit rotate with a phase angle of 180° relative to each other. However, in that case, the exhaust port of each engine unit repeats opening and closing at 120° cycles as the rotor rotates, as shown by the dashed curve in Figure 6, and the exhaust port on the first engine unit side Between the opening/closing characteristics and the opening/closing characteristics of the exhaust boat on the second engine unit side, there are differences between the early exhaust stage of one engine unit (i.e., the operating region where the blowdown phenomenon of exhaust gas occurs) and the mid-exhaust stage of the other engine unit. (i.e., the operating region where the exhaust gas pressure is relatively low) overlap with each other. The term "exhaust stroke period" is a concept that encompasses not only the initial stage of the exhaust stroke but also the stage close to the exhaust stroke that faces the start of the exhaust stroke, and the term "exhaust start stage working chamber" is defined as above. “Exhaust start period”
(used to mean the working chamber in the middle stage of the exhaust stroke) and the mid-exhaust working chamber (the working chamber in the middle stage of the exhaust stroke) on the other side of the engine unit are used to describe the working chamber in the middle stage of the exhaust stroke. communicate with each other at a predetermined timing to cause a part of the high temperature and high pressure exhaust gas in the exhaust start stage working chamber to flow into the adjacent exhaust middle stage working chamber, thereby blowing down the exhaust gas in the exhaust start stage working chamber side. The idea was to suppress the occurrence of this phenomenon.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The exhaust system for a rotary piston engine according to the present invention, which has been developed based on the above technical background, will be specifically described below based on examples.

(First Embodiment) (Structure) FIGS. 1 and 2 show a 20-torque rotary piston engine Z for an automobile equipped with an exhaust system according to a first embodiment of the present invention. , numeral 1 in the figure is a housing assembly constituted by a pair of side housings 2.3, a pair of rotor housings '41.5 whose inner peripheral surfaces are trochoidal surfaces, and - intermediate housings 6. A trochoidal space 10.11 is formed inside each rotor housing 4.5 on both sides of the intermediate housing 6.

This pair of trochoid spaces 10. Rotors 7.8 that perform planetary rotational motion around the eccentric shaft portion 9a of the eccentric shaft 9 are fitted inside the II, and the rotors 7.8, 7.8, and 7.8, respectively, are fitted into the first engine unit Xl and the second engine unit X2. It consists of

” As shown in FIGS. 1 and 2, the bipedal intermediate housing 6 has a sliding surface 6 for the first engine unit x + m++ of the intermediate housing 6.
a, and a pair of left and right intake ports each opening on the sliding surface 6b on the second engine unit X2 side)! 3A and 14A are formed. These two intake boats 13A, +4A
are paired with the intake boats 13B and 1413 formed on the pair of side/% openings 2.3, respectively, and the intake pipes 18 are connected to the outer ends +1<, respectively.

On the other hand, each engine unit X1. As shown in FIGS. 1 and 2, each rotor housing 1.5 of 15.1
6 are formed respectively.

These two exhaust ports! 5.16 is opened and closed at a rotation period of +20° by the top of each rotor as the corresponding rotor 7.8 rotates, as shown in Fig. 6, but the opening and closing position between the rain sounds is The phase difference is a broken curve σ5.
As shown by u2, there is a phase difference of 180° based on the rotational position difference between the two rotors 7.8. Therefore, the two exhaust ports 15 and 16 have a predetermined period from the predetermined period before the opening of one exhaust port 15 to the first half of the opening period of the same boat I5, and a middle or latter half of the opening period of the other exhaust port I6. They will overlap.

Therefore, in this embodiment, the present invention is applied to provide the intermediate housing 6 with a communication passage 12 that passes through the intermediate housing 6 in the thickness direction.
The communication path 12 connects the trochoid space 10 (text 11) of one engine unit to the exhaust start working chamber (for example, in the rotor rotational position shown in FIG. 1, the second engine unit Side exhaust working chamber I
IA) and the trochoid space II of the other engine unit
(or 10) (for example, the exhaust working chamber 1 on the side of the first engine unit X in FIG. 1)
0A) are communicated with each other. In this case, in this embodiment, the opening timing of the communication passage 12 is set to the exhaust port 15 (or +6) as shown in FIG.
) is set slightly earlier than the opening start timing of the communication passage I2, and on the other hand, the closing timing of the communication passage I2 is set considerably earlier than the closing timing of the exhaust boat 15 (or I'6). . Therefore, the opening period of the communication passage 12 on the first engine unit X1 side and the opening period of the communication passage 12 on the second engine unit X2 side overlap with each other with a predetermined phase difference. The polymerization period (the period indicated by (0) in FIG. 6) is the period during which the communication path 12 is actually opened.

Incidentally, according to the present invention, the opening timing of the communication passage 12 is set to the exhaust port 15 (or 16) as in the example shown in FIG.
) is not limited to the opening timing slightly earlier than the opening timing of the exhaust port 1, as described later.
In order to achieve the purpose of suppressing the blowdown phenomenon at the 5 (or 16) portion, the exhaust port t5 (
Alternatively, the exhaust port 16) may be opened at the same time as the exhaust port 15 (or [6)].

The opening edge shape of the exhaust port +5.16 is a flat opening that is narrow in the circumferential direction of the trochoidal surface and wide in the width direction, but this is based on the requirements for engine operating performance. In other words, (1) In order to suppress the drop in intake filling efficiency caused by the phenomenon of exhaust gas blowing at the exhaust port, the leading edge of the exhaust port in the rotor rotational direction should be set as close to the trailing side as possible and the exhaust boat should be closed. (2) Also, from the point of view of effectively utilizing the energy of combustion gas, the end of the exhaust port on the trailing side in the rotor rotational direction should be set as far as possible on the leading side. The opening width of the exhaust port in the circumferential direction of the trochoid surface is kept as small as possible for two reasons: It is effective to delay the opening timing of the exhaust port.

On the other hand, as the exhaust resistance increases, the output loss of the engine increases accordingly, so from the standpoint of improving output characteristics, the opening area of the exhaust port should be made as large as possible to allow the exhaust residue to flow through the exhaust port. It is necessary to reduce the resistance as much as possible, and for this reason, the exhaust port is opened wide in the width direction of the trochoid.

Furthermore, on the inner surface of the outer end of this exhaust port +5.16,
A trumpet-shaped exhaust insert 21 is attached,
The outer peripheral surface of the exhaust insert 2I and the exhaust port 15.16
An annular secondary air passage 20 is formed between the inner surface of the cylinder and the inner surface of the cylinder.

(Operation and its effects) Next, the operation and its effects of the rotary piston engine Z1 will be explained with reference to FIGS. 6 to 8.

When the engine is operated, each engine unit X1.
In X 2 a rotor 7.8 in each case has a planetary rotation movement around an eccentric shaft 9 and working chambers 10A, 10 formed on the three peripheries of said rotor 7.8.
The air-fuel mixture sucked into B, l QC, 11A, I IB, l lC sequentially goes through the compression → explosion → expansion strokes, and then passes through exhaust port +5.16 to exhaust pipe 17 through L7.
It is discharged to the side. In this case, if the communication passage 12 is not formed in the intermediate housing 6, the high temperature and high pressure exhaust gas will flow from the exhaust initial working chamber to the exhaust passage side immediately after the opening of the exhaust boat 15, 16 as shown in FIG. A blowdown phenomenon occurs in which the exhaust pressure on the exhaust passage side suddenly rises due to a sudden blowout, and as a result, the relatively low-pressure residual exhaust gas remaining in the exhaust passage collides with the above-mentioned blowout exhaust gas. A shock wave is generated, which causes large exhaust noise and vibration, and because a large amount of exhaust gas is rapidly discharged, exhaust resistance increases, leading to a loss of engine output, or a decrease in exhaust gas pressure. As mentioned above, due to this increase, the amount of exhaust gas blown into the intake working chamber side through the exhaust ports 15 and 16 increases, which may cause problems such as a decrease in intake filling efficiency. .

However, in this embodiment, the present invention is applied to form the communication passage 12 in the intermediate housing 6, and the exhaust start working chamber of one engine unit and the other engine unit are connected via the communication passage 12. Since the unit's exhaust medium-term working chamber is communicated with the second
As shown by arrows G in the figures and FIG. 6, a part of the high-temperature, high-pressure exhaust gas G inside the exhaust start stage working chamber flows out through the communication passage 12 to the middle exhaust stage working chamber. Therefore, in the working chamber at the start of exhaust, the amount and gas pressure of exhaust gas ejected from the exhaust port +5 (or +6) are reduced by the amount flowing out to the working chamber during the middle stage of exhaust, so the solid curve in Fig. 8 As shown in Figure 5.16, the increase in exhaust gas pressure on the exhaust port side immediately after opening is in the case of the conventional structure (also connected (K12?
T1. (See Figure 8, dashed curve)
The blowdown phenomenon of the exhaust gas is suppressed as much as possible (blowdown is suppressed only in the shaded area in Fig. 8).
.

Accordingly, the above-mentioned problems caused by the blowdown phenomenon of exhaust gas, that is, increases in exhaust noise and vibration, exhaust output loss, and decrease in intake air filling efficiency, are prevented as much as possible.

In addition, exhaust port I5. The opening area of +6 is set to the minimum area that can suppress the exhaust resistance to a predetermined value or less in the state where the exhaust gas flow 1 is at its maximum, that is, in the state of high-load operation and immediately after the exhaust boat is opened. As in the above embodiment, a part of the exhaust gas is transferred from the working chamber side at the start of exhaust through the communication path 12 to the exhaust port (
15 or 16), the amount of exhaust gas passing through the other side exhaust port (+6 or 15) will be reduced by the amount of the above flow out. 5.1
The opening area of No. 6 can be reduced. in this way,
If the opening area of the exhaust boats I5, 16 can be reduced, the edges of the exhaust boats 15, 16 on the leading side in the rotor rotational direction can be set closer to the trailing side to improve the closing timing of the exhaust boats I5, I6. This makes it possible to further suppress the blow-by of exhaust gas to the intake working chamber side via the exhaust boat +5.16, and the intake air filling efficiency is improved accordingly.

Conversely, the edges of the exhaust boats 15 and 16 on the trailing side in the rotor rotational direction can be set on the leap ink side to delay the opening timing of the exhaust boats 14. The energy of the gas can be used effectively, resulting in improved thermal efficiency.

(Second Embodiment) FIGS. 3 and 4 show a rotary piston engine Z equipped with an exhaust system according to a second embodiment of the present invention. This rotary piston engine Z is basically the same as that of the first embodiment, except that the communication passage 12 formed in the intermediate housing 6 is provided with an on-off valve 30 for opening and closing the communication passage 12. In some respects, this is different from Part B of the first embodiment.

The reasons why the on-off valve 30 is provided in the communication passage 12 are as follows: (1) When the engine is operating under a light load, the amount of exhaust gas itself is small, so the blowdown phenomenon is weak; If a part of the exhaust gas flows out through the communication passage 12 to the working chamber side of the adjacent housing when the amount is low, the water jacket 1 formed around the communication passage 12 when the outflow exhaust gas passes through the communication passage 12
The temperature decreases due to the cooling water in the exhaust gas, and the activity of the catalyst decreases due to the decrease in the exhaust gas temperature, especially in the case of the exhaust gas equipped with a catalytic converter (not shown) for exhaust purification in the exhaust passage. , there is a risk of deterioration of exhaust emission characteristics, and therefore, when the engine is operated under light load, the communication passage I
The reason for this is that it is better to block 2 in terms of exhaust emission characteristics.

The structure and operation of this on-off valve 30 will be explained below.

The on-off valve 30 is constituted by a butterfly valve having a valve stem 31 as shown in FIGS. 4 and 5, and can open and close the communication passage I2 by rotating the valve stem 31. A pressure-responsive actuator 32 is connected to the outer end of the valve stem 31, as shown in FIG. 3, and the valve stem 31 is driven by the actuator 32. Further, intake negative pressure and atmospheric pressure are selectively introduced into the pressure chamber of the actuator 32 via a three-way solenoid valve 33. The operation of this three-way solenoid valve 33 is controlled by a computer 34 that operates in response to a throttle valve opening signal, an engine rotation speed signal, and an engine temperature signal.
For example, the light load operating state of the engine is detected from the throttle valve opening degree and engine speed, and in that case, intake negative pressure is introduced into the actuator 32 and the cough actuator 32 is activated to open and close the valve. The valve 30 may be closed, or the engine temperature (for example, the cooling water temperature) may be detected, and in an operating range where the engine temperature is below a predetermined value, intake negative pressure may be introduced into the actuator 32 to cause the actuator 32 to move. Possible methods include opening the on-off valve 30.

In this case, in addition to obtaining the same effect as in the first embodiment (i.e., the effect of preventing various malfunctions caused by the blowdown phenomenon of exhaust gas), In this way, it is possible to maintain the υF energy retention, which is even more beneficial.

It should be noted that each member of the pond in FIGS. 3 and 4 is designated by the reference numeral U corresponding to each member in FIGS. 1 and 2, and a detailed explanation thereof will be omitted.

(Effects of the Invention) The exhaust system for a rotary piston engine of the present invention includes an intermediate housing, a rotor housing disposed on both sides of the intermediate housing, and a side housing disposed at an end of the engine on the side of the rotor housing. A multi-cylinder rotary piston engine in which a substantially triangular rotor is supported by an eccentric shaft and makes planetary rotation movement in a trochoidal space formed by the intermediate housing or the side housing and the rotor housing. A pair of trochoid cavities adjacent to each other across the housing [
Among the working chambers included in 12, one of the working chambers on the trochoid space side which is in the exhaust stroke start period spanning from just before the start of the exhaust stroke to a predetermined stroke period after the start of the exhaust stroke and the middle or latter half of the exhaust stroke. a communication passage that communicates with the exhaust mid-stage working chamber on the other trochoid space side at a predetermined timing before the exhaust gas blowdown phenomenon occurs in the exhaust boat section on the trochoid space side where the exhaust start stage working chamber is located; is provided in the intermediate housing.

Therefore, according to the exhaust system for a rotary piston engine of the present invention, the exhaust start working chamber of one trochoid space of a pair of adjacent trochoid spaces and the exhaust mid-stage working chamber of the other trochoid space can be used to blow exhaust gas. They are made to communicate with each other via the communication passage at a predetermined timing when the down phenomenon occurs, so that at the start of the exhaust stroke, a portion of the high temperature and high pressure exhaust gas in the working chamber at the start of the exhaust stroke flows through the communication passage. The exhaust gas pressure may flow into the other trochoid space (Ill?), where the exhaust gas pressure is relatively low, to the exhaust mid-stage working chamber side, and an exhaust gas blowdown phenomenon may occur in the exhaust boat section on the exhaust start stage working chamber side. As a result, the exhaust noise, vibration, and exhaust resistance caused by the blowdown phenomenon are reduced, and the intake air filling efficiency is improved.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of a rotary piston engine equipped with an exhaust system according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■ of FIG. 1, and FIG. FIG. 4 is a longitudinal cross-sectional view of a main part of a rotary piston engine equipped with an exhaust system according to a second embodiment of the present invention, FIG. 6 is an operating characteristic diagram of the exhaust port and communication passage of the rotary piston engine shown in FIG. 1, and FIGS. 7 and 8 are exhaust gas pressure characteristic diagrams. 1 ...Housing assembly 2.3 ...Side housing 4.5 ...Rotor housing 6 ...Intermediate housing 7.8
...Rotor 9 ...Eccentric Yaft 10.11
... Trochoid space 12 ... Communication path l fl r3 15, 16 ... Exhaust port 30 ... Opening/closing valves X,, X2 ... Engine unit/ ...
...Housing assembly 2.3 ...Side housing 74.5 ...Rotor housing 6 ...Intermediate housing 7, g
...Rotor 9 ...Eccentric shaft 10, //
... Trochoid space 30 ... Opening/closing valve XI + X2 ---1 engine 221 nt Fig. 4

Claims (1)

[Claims] 1. An intermediate housing and rotor housings disposed on both sides of the intermediate housing;
A side housing is provided at the end of the engine on the side of the rotor housing, and a substantially triangular rotor is supported by an eccentric shaft in a trochoidal space formed by the intermediate housing or the side housing and the rotor housing. In a multi-cylinder rotary piston engine that performs planetary rotation motion, the trochoidal space is located between a predetermined stroke period from just before the start of the exhaust stroke to after the start of the exhaust stroke in each working chamber included in a pair of adjacent trochoid spaces with an intermediate housing in between. The exhaust start working chamber on one side of the trochoid space that is at the start of the exhaust stroke and the middle exhaust working chamber on the other trochoid space that is in the middle or latter half of the exhaust stroke are defined as the trochoid space in which the exhaust start working chamber is located. An exhaust system for a rotary piston engine, characterized in that the intermediate housing is provided with a communication path that communicates with the exhaust gas at a predetermined timing before a blowdown phenomenon of exhaust gas occurs at the side exhaust port.