JP2017082742A - Rotary piston engine with turbo supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a residual exhaust gas, to reduce pump loss, and to improve turbine efficiency, by preventing exhaust interference in a rotary piston engine with a turbo supercharger of multi-cylinder in which each cylinder has a side exhaust port.SOLUTION: A plurality of cylinders of a rotary piston engine 1 include a cylinder of a first type (front-side cylinder 31a) connected to a turbine 51 through a first exhaust passage 131, and a cylinder of a second type (rear-side cylinder 31b) bypassing the turbine by being connected to a second exhaust passage 132 joined to the first exhaust passage at the downstream of the turbine. Exhaust ports 10a, 10b of the cylinder of the first type are disposed on side housings 4, 41 at both sides, and an exhaust port 19c of the cylinder of the second type is disposed on the side housing 41 at one side. The total passage cross-sectional area of the exhaust port per one cylinder of the cylinder of the first type is larger than the total passage cross-sectional area of the exhaust port per one cylinder of the cylinder of the second type.SELECTED DRAWING: Figure 2

Description

  The technology disclosed herein relates to a rotary piston engine with a turbocharger.

  Patent Document 1 describes a multi-cylinder rotary piston engine having two cylinders as a rotary piston engine with a turbocharger. In this rotary piston engine, each cylinder has a side exhaust port opened on the side surface of the intermediate housing in addition to the peripheral exhaust port opened in the rotor housing. In the intermediate housing, there is provided a communicating portion for communicating two side exhaust ports communicating with the two cylinders on both sides. The communication portion is connected to the downstream of the turbine of the turbocharger via a bypass passage, and an open / close valve that opens and closes according to the supercharging pressure of the intake air is provided in the bypass passage.

Japanese Patent Publication No. 6-47942

  In the rotary piston engine described in Patent Document 1, the exhaust ports of the two cylinders communicate with each other through the communication portion. In a two-cylinder rotary piston engine, the partial periods of the exhaust strokes of the two cylinders overlap, so that a part of the exhaust gas discharged from one cylinder causes exhaust interference flowing into the other cylinder.

  Moreover, in general, in a multi-cylinder rotary piston engine in which each cylinder has a side exhaust port, instead of the special configuration described in Patent Document 1, the cylinders on both sides are disposed in the intermediate housing. Two side exhaust ports communicating with each other are formed independently. It is difficult to increase the thickness of the intermediate housing. For this reason, the two side exhaust ports formed in the intermediate housing are configured such that their respective passage areas are reduced and merge in the middle, but this configuration causes exhaust interference. Due to the exhaust interference, there is a disadvantage that the residual exhaust gas in the cylinder increases. In addition, the pump loss increases. Furthermore, in a rotary piston engine with a turbocharger, the exhaust energy supplied to the turbine is reduced due to exhaust interference, which causes a disadvantage that the turbine efficiency is lowered. Further, since the exhaust resistance is increased by the turbine, exhaust interference is also promoted in a rotary piston engine with a turbocharger.

  The technology disclosed herein has been made in view of such a point, and the object of the technology is to prevent exhaust interference in a multi-cylinder rotary piston engine with a turbocharger in which each cylinder has a side exhaust port. By preventing this, it is intended to reduce residual exhaust gas, reduce pump loss, and improve turbine efficiency.

  The technology disclosed herein relates to a rotary piston engine with a turbocharger. The rotary piston engine with a turbocharger includes an engine configured to have a plurality of cylinders, an exhaust passage configured to flow exhaust gas discharged from each of the plurality of cylinders, and the exhaust passage. And a turbocharger configured to have a configured turbine.

  The engine includes a plurality of rotors corresponding to the plurality of cylinders, a rotor housing configured to have a trochoid inner peripheral surface on which each of the plurality of rotors slides, between the rotor housings, and the rotor And a side housing configured to partition the cylinder housing the rotor together with the rotor housing by being disposed on a side portion of the housing.

  An exhaust port that connects the cylinder and the exhaust passage is provided in the side housing and is open to a side surface of the side housing so as to face the cylinder, and the plurality of cylinders includes a first exhaust. A first type cylinder connected to the turbine through a passage and a second type cylinder that bypasses the turbine by connecting a second exhaust passage that gathers with the first exhaust passage downstream of the turbine. The exhaust port of the first type cylinder is provided in each of the side housings on both sides of the rotor housing, and each exhaust port opens into the first type cylinder, The exhaust port of the second type cylinder is provided in the side housing on one side of the rotor housing where the exhaust port of the first type cylinder is not provided. And the sum of the passage sectional areas of the exhaust ports per cylinder of the first type cylinder is the exhaust port per cylinder of the second type cylinder. It is larger than the total of the passage cross-sectional areas of

  According to this configuration, in the multi-cylinder rotary piston engine, the plurality of cylinders are divided into a first type cylinder and a second type cylinder. The case where the number of the first type cylinder is one or the case where there are a plurality of cylinders is included. When there are a plurality of first type cylinders, the plurality of cylinders are preferably cylinders that do not cause exhaust interference. Similarly, the case where the number of the second type cylinders is one or the case where there are a plurality of cylinders is included. In addition, when there are a plurality of second type cylinders, it is desirable that the plurality of cylinders are cylinders that do not cause exhaust interference.

  The first type cylinder is connected to the turbine through the first exhaust passage. The second type cylinder bypasses the turbine by the second exhaust passage. The second exhaust passage gathers with the first exhaust passage downstream of the turbine.

  The exhaust port of the first type cylinder is provided in each of the side housings on both sides of the rotor housing, and each exhaust port opens into the first type cylinder. Here, the side housing also includes an intermediate housing disposed between the rotor housing and the rotor housing. As will be described later, since the exhaust port of the second type cylinder is provided in the side housing in which the exhaust port of the first type cylinder is not provided, only the exhaust port of the first type cylinder is provided in the intermediate housing. Provided. It is possible to form the exhaust port of the first type cylinder having a sufficient cross-sectional area while the thickness of the intermediate housing is relatively thin. Further, it is possible to form the exhaust port of the first type cylinder having a sufficient passage sectional area in the side housing disposed on the side of the rotor housing.

  The exhaust port of the second type cylinder is provided in the side housing on one side of the rotor housing and opens into the second type cylinder. Since the exhaust port of the second type cylinder is provided in the side housing where the exhaust port of the first type cylinder is not provided, the exhaust port of the second type cylinder having a sufficient passage cross-sectional area can be formed. It becomes possible.

  Thus, upstream of the turbine, the exhaust port and the first exhaust passage of the first type cylinder, and the exhaust port and the second exhaust passage of the second type cylinder become independent from each other. As a result, exhaust interference is eliminated in a multi-cylinder rotary piston engine in which each cylinder has a side exhaust port. It becomes possible to reduce the residual exhaust gas in the cylinder.

  Further, the exhaust energy supplied to the turbine through the first exhaust passage can be increased by the amount of exhaust interference. The turbine efficiency is improved.

  Here, the sum of the cross-sectional areas of the exhaust ports per cylinder of the first type cylinder is larger than the sum of the cross-sectional areas of the exhaust ports per cylinder of the second type cylinder. The exhaust port of the first type cylinder connected to the turbine and the first exhaust passage may have a high exhaust resistance, but an increase in the exhaust resistance is suppressed by making the passage cross-sectional area relatively large. . The energy of the exhaust gas discharged from the first type cylinder can be efficiently supplied to the turbine.

  On the other hand, the exhaust port of the second type cylinder and the second exhaust passage have a relatively small passage cross-sectional area, but the second exhaust passage is not connected to the turbine, so the exhaust resistance is relatively low. . Even if the second exhaust passage has a relatively small passage cross-sectional area, an increase in exhaust resistance is suppressed. The exhaust gas discharged from the second type cylinder can also be discharged smoothly.

  Pump loss is reduced in an engine with a turbocharger by avoiding exhaust interference and reducing exhaust resistance.

  In the second exhaust passage, an opening end portion that gathers with the first exhaust passage on the downstream side of the turbine is substantially the same as the flow direction of the first exhaust passage. It is good also as providing the aperture_diaphragm | restriction provided adjacent to the opening edge part of an exhaust passage, and reducing a passage area.

  With this configuration, the flow velocity of the exhaust gas flow from the second exhaust passage is increased by the throttle at the gathering location of the first exhaust passage and the second exhaust passage, and the opening end of the second exhaust passage A strong negative pressure is generated around the ejector (ejector effect). By this ejector effect, the exhaust gas flowing through the first exhaust passage is sucked out, and the pressure on the downstream side of the turbine is reduced. The pressure difference between the upstream side and the downstream side of the turbine is increased, and the turbine efficiency is increased. In this configuration, in the multi-cylinder rotary piston engine, only the exhaust gas discharged from some cylinders is supplied to the turbine, that is, the configuration in which the exhaust energy supplied to the turbine can be reduced, This is advantageous in realizing a desired supercharging pressure.

  The second exhaust passage may be made of a sheet material.

  As described above, since the second exhaust passage is an exhaust passage that bypasses the turbine, the temperature is relatively low. The second exhaust passage can be formed of a sheet material. On the other hand, since the first exhaust passage is an exhaust passage connected to the turbine, the temperature is relatively high. It is difficult to configure the first exhaust passage with a sheet material. The first exhaust passage is made of, for example, a casting.

  The second exhaust passage is made of a sheet material to reduce the heat capacity. When the catalyst device is inactive, exhaust gas having a relatively high temperature can be sent to the catalyst device through the second exhaust passage. This is advantageous for early activation of the catalyst device.

  In the first exhaust passage upstream of the turbine, a restriction portion configured to restrict the inflow of exhaust gas to the turbine and a state communicating with the second exhaust passage upstream of the restriction portion A communication portion configured to switch to a state in which the first exhaust passage and the second exhaust passage are gathered, and the catalyst device disposed downstream of the first exhaust passage and the second exhaust passage is inactive. In this case, the restricting portion restricts the exhaust gas discharged from the first type cylinder from flowing into the turbine, and the communicating portion enters a communicating state, thereby bypassing the turbine and The exhaust gas discharged from the first type cylinder may be sent to the second exhaust passage.

  Since the second exhaust passage bypasses the turbine and is connected to the catalyst device, relatively high-temperature exhaust gas can be supplied to the catalyst device. Therefore, when the catalyst device is inactive, the restriction portion restricts the exhaust gas discharged from the first type cylinder from flowing into the turbine, and the communication portion enters the communication state. The exhaust gas discharged from the cylinder is sent to the second exhaust passage by bypassing the turbine. In this way, when the catalyst device is inactive, exhaust gas discharged from each of the first type cylinder and the second type cylinder is sent to the catalyst device by bypassing the turbine as much as possible. As a result, high-temperature exhaust gas is supplied to the catalyst device. The catalyst device is activated, and the catalyst device is activated early.

  In particular, when the second exhaust passage is made of a sheet material, exhaust gas discharged from each of the first type cylinder and the second type cylinder is sent to the catalyst device through the second passage having a small heat capacity. As a result, it becomes possible to send a higher temperature exhaust gas to the catalyst device. The catalyst device can be activated quickly.

  For example, the limiting portion may be configured by a VGT (Variable Geometry Turbo) vane configured to change the passage area of the exhaust gas in the housing of the turbine. By changing the vane angle, the passage area of the exhaust gas is reduced, and the exhaust gas is restricted from flowing into the turbine. Further, the communication portion may be constituted by an on-off valve provided at a location where the first exhaust passage and the second exhaust passage are communicated.

In the first exhaust passage, an O ₂ sensor for cylinder identification may be disposed downstream of the turbine and upstream of a location where the second exhaust passage gathers.

In a multi-cylinder rotary piston engine, exhaust strokes greatly overlap between cylinders. As employed in a reciprocating engine, a method of identifying a cylinder by changing the air-fuel ratio in each cylinder using an O ₂ sensor disposed downstream of a collection point of exhaust gas from each cylinder, Even when trying to adopt it in a rotary piston engine, accurate cylinder identification is difficult.

In the above configuration, the first exhaust passage connected to the first type cylinder and the second exhaust passage connected to the second type cylinder are independent. That is, only the exhaust gas discharged from the first type cylinder flows downstream of the turbine and upstream of the location where it gathers with the second exhaust passage. Therefore, by disposing the O ₂ sensor at this location, it is possible to distinguish between the first type cylinder and the second type cylinder. This configuration is particularly effective for cylinder identification in a two-cylinder rotary piston engine.

  As described above, according to the above-mentioned rotary piston engine with a turbocharger, the exhaust port and the first passage connected to the first type cylinder are connected to the turbine, while being connected to the second type cylinder. The exhaust port and the second passage to be collected in the first passage bypassing the turbine, and the passage sectional area of the exhaust port of the first type cylinder is defined as the passage sectional area of the exhaust port of the second type cylinder. By making it larger than this, exhaust interference is prevented, and in a rotary piston engine with a turbocharger, residual exhaust gas can be reduced, pump loss can be reduced, and turbine efficiency can be improved.

FIG. 1 is a cross-sectional view showing a configuration of a rotary piston engine. FIG. 2 is an explanatory diagram showing a configuration of an exhaust device of a rotary piston engine with a turbocharger.

  Hereinafter, a rotary piston engine with a turbocharger disclosed herein will be described with reference to the drawings. In addition, the structure of the rotary piston engine with a turbocharger shown below is an example. 1 and 2 show the structure of a rotary piston engine 1 (hereinafter also simply referred to as a rotary engine 1). The rotary engine 1 is a two-rotor type including two rotors 2 as shown in FIG. A two-rotor (in other words, two-cylinder) rotary engine 1 has two rotor housings 3, 3 on the front side (for convenience, the left side in FIG. 2) and the rear side (for convenience, on the right side in FIG. 2). (That is, the side housing 4) is sandwiched between the two side housings 41 and 41 from both sides and integrated. The number of rotors 2 (that is, the number of cylinders) is not limited to this.

  The trochoid inner peripheral surface 3 a drawn by the parallel trochoid curve of the rotor housing 3, the side surface 41 a of the side housing 41 sandwiching the rotor housing 3 from both sides, and the side surfaces 4 a on both sides of the intermediate housing 4, When the rotary piston engine 1 is viewed from the one side in the direction along the rotation axis X, the rotor accommodating chamber 31 having a substantially elliptical shape like a bag is divided into two on the front side and the rear side. One rotor 2 is housed in each of the rotor housing chambers 31. Each rotor accommodating chamber 31 is arranged symmetrically with respect to the intermediate housing 4. Since the configuration is the same except that the position and phase of the rotor 2 are different, only one rotor accommodating chamber 31 will be described below.

  The rotor 2 is formed of a substantially triangular block body in which the central part of each side bulges when viewed from the direction of the rotation axis X. The rotor 2 includes three substantially rectangular flank surfaces 2a, 2a, and 2a on the outer periphery thereof.

  The rotor 2 has an apex seal (not shown) at each top. These apex seals are in sliding contact with the trochoid inner peripheral surface 3 a of the rotor housing 3. The trochoid inner peripheral surface 3 a of the rotor housing 3, the side surface 4 a of the intermediate housing 4, the side surface 41 a of the side housing 41, and the flank surface 2 a of the rotor 2 have three working chambers inside the rotor accommodating chamber 31. 8, 8, and 8 are partitioned. Accordingly, the engine 1 has a total of six working chambers, that is, the first to third three working chambers 8 in the front cylinder 31a and the fourth to sixth three working chambers 8 in the rear cylinder 31b. ing.

  A phase gear is provided inside the rotor 2 (not shown). That is, the internal gear (rotor gear) inside the rotor 2 and the external gear (fixed gear) on the side housing 41 side mesh with each other. The rotor 2 is supported so as to make a planetary rotational movement with respect to the eccentric shaft 6 constituting the output shaft X. The eccentric shaft 6 passes through the intermediate housing 4 and the side housing 41. Reference numeral 21 denotes an oil seal provided on the side surface of the rotor 2 and prevents excess lubricating oil from flowing into the working chamber 8.

  The rotational motion of the rotor 2 is defined by the meshing of the internal gear and the external gear. The rotor 2 rotates around the rotation axis X while rotating around the eccentric ring (eccentric shaft) 6a of the eccentric shaft 6 while the three seal portions are in sliding contact with the trochoid inner peripheral surface 3a of the rotor housing 3, respectively. Revolves in the same direction (including the rotation and revolution, simply the rotation of the rotor in a broad sense). Then, the three working chambers 8, 8, and 8 move in the circumferential direction while the rotor 2 makes one rotation, and intake, compression, expansion (combustion), and exhaust strokes are performed respectively. The rotational force generated by this cycle is output from the eccentric shaft 6 via the rotor 2.

  More specifically, the rotor 2 rotates clockwise as indicated by an arrow. The right side of the rotor accommodating chamber 31 divided by the major axis Y of the rotor accommodating chamber 31 passing through the rotation axis X is a region for intake and exhaust strokes, and the left side is a region for compression and expansion strokes.

  Here, in the rotary piston engine of the conventional configuration, the left side of the rotor accommodating chamber 31 that is divided by the long axis Y is a region for the intake and exhaust strokes, and the right side is a region for the compression and expansion strokes. The rotary piston engine of this configuration is mounted on a vehicle in a state where the rotary piston engine of the conventional configuration is rotated 180 ° about the rotation axis X. However, the mounting state of the rotary piston engine may be the same mounting state as before.

  When attention is paid to the lower right working chamber 8 in FIG. 1, this shows an intake stroke in which an air-fuel mixture is formed by intake air and injected fuel. When this working chamber 8 shifts to the compression stroke as the rotor 2 rotates, the air-fuel mixture is compressed therein. Thereafter, as in the working chamber 8 shown on the left side of FIG. 1, the ignition plugs 82 and 83 are ignited at a predetermined timing from the final stage of the compression stroke to the expansion stroke, and the combustion / expansion stroke is performed. When the exhaust stroke such as the working chamber 8 in the upper right of FIG. 1 is finally reached, the combustion gas is exhausted from the exhaust port 10 and then returns to the intake stroke to repeat each stroke.

  An intake port 11 communicates with the working chamber 8 in the intake stroke state. More specifically, the opening portion of the intake port 11 is formed on the side surface 4a of the intermediate housing 4 facing the working chamber 8 in the intake stroke state, on the outer side of the rotor storage chamber 31 and accommodates the rotor passing through the rotation axis X. The chamber 31 is provided near the short axis Z. The intake port 11 extends in the intermediate housing 4 in a substantially horizontal direction and opens on the side surface of the engine 1. Although not shown, another intake port opening is provided on the side surface 41a of the side housing 41 facing the working chamber 8 in the intake stroke state so as to face the opening of the intake port 11. It has been. This intake port also extends in the side housing 41 in a substantially horizontal direction and opens on the side surface of the engine 1. An independent passage 12 of an intake manifold that communicates with the intake port 11 is attached to a side surface of the engine 1.

  An exhaust port 10 communicates with the working chamber 8 in the exhaust stroke state. More specifically, the opening of the exhaust port 10 is formed on the side surface 4a of the intermediate housing 4 and / or the side surface 41a of the side housing 41 facing the working chamber 8 in the exhaust stroke state. Near the short axis Z on the outer peripheral side. The exhaust port 10 extends obliquely upward in the intermediate housing 4 or the side housing 41 and opens near the corner between the upper surface and the side surface of the engine 1. This engine 1 employs a so-called side exhaust system, and the position and shape of the opening of the exhaust port 10 are set so that the intake open timing and the exhaust open timing do not overlap. As a result, the residual exhaust gas brought into the next stroke is reduced. An exhaust passage 13 that communicates with the exhaust port 10 is connected to the engine 1. Details of the configuration of the exhaust port 10 and the exhaust passage 13 will be described later.

  An injector 81 for supplying fuel into the working chamber 8 is attached to the intermediate housing 4. The injector 81 injects fuel into the intake port 11 provided in the intermediate housing 4.

  A T-side spark plug 82 and an L-side spark plug are respectively provided at a trailing side (lag side) position and a leading side (lead side) position in the rotor rotation direction across the short axis Z at the side of the rotor housing 3. 83 is attached. These two spark plugs 82 and 83 face the working chamber 8 in a compressed / expanded state, and ignite the air-fuel mixture in the working chamber 8 simultaneously or sequentially with a phase difference.

  FIG. 2 shows the configuration of the exhaust device of the rotary engine 1 with a turbocharger. The exhaust device includes an exhaust passage 13 connected to an exhaust port, a turbine 51 of the turbocharger 5, and a catalyst device 100 downstream thereof. The catalyst device 100 includes a three-way catalyst, for example.

  As described above, in the two-rotor type rotary engine 1, each cylinder (that is, the rotor accommodating chamber 31 that accommodates the rotor 2) is referred to as a front cylinder 31a. The right cylinder in FIG. 2 is called a rear cylinder 31b), and an exhaust port 10 is provided.

  The exhaust port 10 of the front cylinder 31 a is provided in both the side housing 41 and the intermediate housing 4. That is, the exhaust port 10 of the front cylinder 31 a includes an exhaust port 10 a provided in the side housing 41 and an exhaust port 10 b provided in the intermediate housing 4. Here, the intermediate housing 4 is provided with only the exhaust port 10b of the front cylinder 31a. The exhaust port 10b having a sufficient cross-sectional area can be formed while the thickness of the intermediate housing 4 is relatively thin.

  A first exhaust passage 131 is connected to the exhaust port 10 of the front cylinder 31a. The first exhaust passage 131 includes an independent passage connected to each of the two exhaust ports 10a and 10b and a merge passage where the two independent passages merge. A turbine housing 53 that houses the turbine 51 is provided in the middle of the merging passage. Since the first exhaust passage 131 is connected to the turbine 51, the first exhaust passage 131 is formed of a casting as a heat countermeasure. In FIG. 2, the first exhaust passage 131 made of a casting is drawn thick. In the rotary engine 1, the front cylinder 31 a corresponds to a first type cylinder connected to the turbine 51. Since the first exhaust passage 131 connected to the front cylinder 31a is independent of the rear cylinder 31b, it is possible to avoid exhaust interference and supply high exhaust energy to the turbine 51.

  The exhaust port 10c of the rear cylinder 31b is provided only in the side housing 41. Accordingly, the sum of the passage sectional areas of the exhaust ports 10a and 10b of the front cylinder 31a is larger than the passage sectional area of the exhaust port 10c of the rear cylinder 31b. Although the exhaust resistance of the first exhaust passage 131 connected to the turbine 51 can be high, the increase in the exhaust resistance of the front cylinder 31a is suppressed because the passage cross-sectional areas of the exhaust ports 10a and 10b are relatively large. .

  A second exhaust passage 132 is connected to the exhaust port 10c of the rear cylinder 31b. The second exhaust passage 132 bypasses the turbine 51 and gathers with the first exhaust passage 131 downstream of the turbine 51. The exhaust port 10c connected to the second exhaust passage 132 has a relatively small passage sectional area. However, since the second exhaust passage 132 bypasses the turbine 51, the rear cylinder 31b also has an increased exhaust resistance. Is suppressed.

  At the location where the first exhaust passage 131 and the second exhaust passage 132 are gathered, the opening end of the second exhaust passage 132 is provided adjacent to the opening end of the first exhaust passage 131. . In the example of FIG. 2, the opening end portion of the second exhaust passage 132 is provided so as to surround the periphery of the opening end portion of the first exhaust passage 131. Thereby, the flow of the exhaust gas discharged from the opening end portion of the first exhaust passage 131 and the flow of the exhaust gas discharged from the opening end portion of the second exhaust passage 132 are substantially in the same direction. The opening end of the second exhaust passage 132 is also provided with a throttle 1321 that reduces the passage area. Thereby, the flow velocity of the exhaust gas discharged from the second exhaust passage 132 is increased, and a strong negative pressure is generated around the opening end portion of the second exhaust passage 132 by the ejector effect. This strong negative pressure draws out the exhaust gas from the first exhaust passage 131, and the pressure on the downstream side of the turbine 51 decreases. As a result, the pressure difference between the upstream side and the downstream side of the turbine 51 is increased, and the turbine efficiency is increased.

  Since the second exhaust passage 132 is a passage that bypasses the turbine 51, the temperature is lower than that of the first exhaust passage 131. The second exhaust passage 132 is made of a sheet material (for example, a steel plate). Thereby, the heat capacity of the second exhaust passage 132 is smaller than the heat capacity of the first exhaust passage 131. In FIG. 2, the second exhaust passage 132 made of a sheet material is drawn thin. In the rotary engine 1, the rear cylinder 31 b corresponds to a second type cylinder that bypasses the turbine 51.

  The turbine upstream of the first exhaust passage 131 and the upstream of the gathering location of the second exhaust passage 132 communicate with each other. A bypass valve 133 is interposed at this communication location. The bypass valve 133 communicates the upstream side of the turbine 51 in the first exhaust passage 131 with the second exhaust passage 132 at the time of valve opening indicated by a solid line in FIG. The first exhaust passage 131 and the second exhaust passage 132 are made independent of each other upstream of the turbine 51. As will be described later, when the catalyst device 100 is inactive, the bypass valve 133 is opened. The catalyst device 100 is disposed downstream of the gathering location of the first exhaust passage 131 and the second exhaust passage 132.

In the exhaust passage 13, an O ₂ sensor 134 is disposed downstream of the gathering point of the first exhaust passage 131 and the second exhaust passage 132 and upstream of the catalyst device 100. The O ₂ sensor 134 is configured to detect the oxygen concentration in the exhaust gas. The detection result of the O ₂ sensor 134 is used for various controls. Here, it is particularly used for detecting the combustion state in the rotary engine 1. Specifically, the occurrence of incomplete combustion or the like is detected.

An O ₂ sensor 135 (that is, a cylinder identifying O ₂ sensor 135) for identifying a cylinder whose combustion state has deteriorated in relation to detection of the combustion state is disposed in the first exhaust passage 131. More specifically, the cylinder identifying O ₂ sensor 135 is disposed downstream of the turbine 51 and upstream of the collection point of the first exhaust passage 131 and the second exhaust passage 132. This place in the exhaust passage 13 is a place through which only the exhaust gas discharged from the front cylinder 31a passes. Therefore, the front cylinder 31a and the rear cylinder 31b can be identified by comparing the detection value of the O ₂ sensor 134 upstream of the catalyst device 100 with the detection value of the cylinder identification O ₂ sensor 135. Specifically, when the occurrence of incomplete combustion or the like is detected based on the detection value of the O ₂ sensor 134 upstream of the catalyst device 100, the detection value of the cylinder identification O ₂ sensor 135 shows the same tendency. It is possible to determine that incomplete combustion or the like has occurred in the front cylinder 31a. Conversely, when the detection value of the cylinder identifying O ₂ sensor 135 does not show the same tendency, it is possible to determine that incomplete combustion or the like has occurred in the rear cylinder 31b. Further, since the temperature of the exhaust gas is lowered on the downstream side of the turbine 51, the arrangement of the O ₂ sensor 135 at this location also has an advantage that an O ₂ sensor having a low heat resistance temperature can be used. is there.

  The turbocharger 5 is a VGT in which a vane 54 is provided in a turbine housing 53 as schematically shown in FIG. That is, the VGT is configured to change the passage area of the exhaust gas in the turbine housing 53 by changing the angle of the vane 54 according to the operating state of the rotary engine 1. As will be described in detail later, in this rotary engine 1, in addition to changing the angle of the vane 54 according to the operating state of the rotary engine 1, the passage area of the exhaust gas is reduced even when the catalyst device 100 is inactive. Next, the angle of the vane 54 is changed.

  The operation of the angle of the vane 54 of the turbocharger 5 and the opening / closing of the bypass valve 133 described above are controlled by a PCM (Powertrain Control Module) (not shown).

  Although not shown in FIG. 2, the compressor 52 of the turbocharger 5 is disposed in the intake passage. The intake passage is branched downstream of the compressor 52 into an independent passage 12 connected to the front cylinder 31a and an independent passage 12 connected to the rear cylinder 31b. Therefore, as described above, only the front cylinder 31a of the front cylinder 31a and the rear cylinder 31b is connected to the turbine 51 of the turbocharger 5, but the front cylinder 31a and the rear cylinder 31b are connected to the compressor 52. Both side cylinders 31b are connected. Supercharging is performed on each of the front cylinder 31a and the rear cylinder 31b.

  As described above, the turbocharger-equipped rotary piston engine 1 disclosed herein includes the engine 1 configured to have a plurality of cylinders 31a and 31b and the exhaust discharged from each of the plurality of cylinders 31a and 31b. The exhaust passage 13 is configured to flow gas, and the turbocharger 5 is configured to include a turbine 51 disposed in the exhaust passage 13.

  The rotary piston engine 1 includes a rotor housing 3 configured to have a plurality of rotors 2 corresponding to the plurality of cylinders 31a and 31b, and a trochoid inner peripheral surface 3a on which the plurality of rotors 2 slide, Side housings arranged between the rotor housings 3 and on the side of the rotor housing 3 so as to partition the cylinders 31 a and 31 b that house the rotor 2 together with the rotor housing 3. 41 and an intermediate housing 4.

  Exhaust ports 10a, 10b, and 10c that connect the cylinders 31a and 31b and the exhaust passage 13 are provided in the side housing 41 and the intermediate housing 4, and the side housing faces the cylinders 31a and 31b. 41 and the intermediate housing 4, and the plurality of cylinders 31 a and 31 b are connected to the turbine 51 through the first exhaust passage 131 and the first type cylinder (that is, the front cylinder 31 a). A second type of cylinder (that is, a rear cylinder) 31b that bypasses the turbine 51 by connecting a second exhaust path 132 that gathers with the first exhaust path 131 downstream of the turbine 51. The exhaust ports 10a and 10b of the front cylinder 31a include the rotor housing 3. The exhaust ports 10a and 10b are provided in the side housing 41 and the intermediate housing 4 on both sides, respectively, and the exhaust ports 10a and 10b open into the front cylinder 31a. The exhaust port 10c of the rear cylinder 31b One side of the rotor housing 3 is provided in the side housing 41 where the exhaust ports 10a, 10b of the front cylinder 31a are not provided, and opens into the rear cylinder 31b, and the exhaust of the front cylinder 31a. The sum of the passage cross-sectional areas of the ports 10a and 10b is larger than (the total of) the passage cross-sectional areas of the exhaust port 10c of the rear cylinder 31b.

  With this configuration, the intermediate housing 4 is provided with only the exhaust port 10b of the front cylinder 31a. The exhaust port 10b having a sufficient cross-sectional area can be formed while the thickness of the intermediate housing 4 is relatively thin.

  Further, the exhaust ports 10a and 10b and the first exhaust passage 131 of the front cylinder 31a, and the exhaust port 10c and the second exhaust passage 132 of the rear cylinder 31b become independent from each other. In the rotary piston engine 1, the exhaust strokes of the two cylinders overlap. However, since the exhaust ports and the exhaust passages of the two cylinders are independent of each other upstream of the turbine 51, no exhaust interference occurs. This makes it possible to reduce the residual exhaust gas in the front cylinder 31a and the rear cylinder 31b.

  Further, the exhaust energy supplied to the turbine 51 through the first exhaust passage 131 can be increased by the amount of exhaust interference. The turbine efficiency is improved.

  Further, since the exhaust ports 10a and 10b and the first exhaust passage 131 of the front cylinder 31a are connected to the turbine 51, the exhaust resistance can be increased. However, by increasing the passage cross-sectional area, the exhaust resistance can be reduced. Increase is suppressed. The energy of the exhaust gas discharged from the front cylinder 31a can be efficiently supplied to the turbine 51.

  On the other hand, the exhaust port 10c of the rear cylinder 31b and the second exhaust passage 132 have a relatively small passage cross-sectional area, but the second exhaust passage 132 is not connected to the turbine 51, so the exhaust resistance is low. . For this reason, even if the passage sectional area is relatively small, the second exhaust passage 132 is suppressed from increasing in exhaust resistance. The exhaust gas discharged from the rear cylinder 31b can also be discharged smoothly.

  Thus, the pump loss of the rotary piston engine 1 with a turbocharger is reduced by avoiding exhaust interference and reducing the exhaust resistance in the first and second exhaust passages 132.

  In the second exhaust passage 132, the opening end portion that gathers with the first exhaust passage 131 on the downstream side of the turbine 51 is substantially the same as the flow direction of the first exhaust passage 131. A throttle 1321 is provided adjacent to the opening end of the first exhaust passage 131 and reduces the passage area.

  With this configuration, the flow velocity of the exhaust gas flow from the second exhaust passage 132 is increased by the throttle 1321 at the gathering location of the first exhaust passage 131 and the second exhaust passage 132, and an ejector effect is obtained. (See the white arrow in FIG. 2). Due to the ejector effect, a strong negative pressure is generated around the open end of the second exhaust passage 132. As a result, the exhaust gas flowing through the first exhaust passage 131 is sucked out, and the pressure on the downstream side of the turbine 51 decreases. The pressure difference between the upstream side and the downstream side of the turbine 51 is increased, and the turbine efficiency is increased. Only the exhaust gas from the front cylinder 31 a is supplied to the turbine 51, and the exhaust energy supplied to the turbine 51 may be relatively lowered, but is exhausted from the rear cylinder 31 b that bypasses the turbine 51. By increasing the turbine efficiency using the energy of the exhaust gas, it is possible to realize a desired supercharging pressure.

  Further, in the high engine speed range, the pressure on the downstream side of the turbine 51 decreases due to the ejector effect, thereby reducing the pump loss.

  In the first exhaust passage 131, upstream of the turbine 51, a restricting portion configured to restrict the inflow of exhaust gas to the turbine 51 (that is, the VGT vane 54), and upstream of the vane 54. A communication portion (that is, a bypass valve 133) configured to switch between a state communicating with the second exhaust passage 132 and a state not communicating with the second exhaust passage 132, and the first exhaust passage 131 and the second exhaust passage 131 are arranged. When the catalytic device 100 disposed downstream of the gathering position with the exhaust passage 132 is inactive, the exhaust gas discharged from the front cylinder 31a is changed by changing the angle of the vane 54. By opening the bypass valve 133 while restricting the flow into the engine, the turbine 51 is bypassed and discharged from the front cylinder 31a. Send exhaust gas to the second exhaust passage 132.

  As a result, when the catalyst device 100 is inactive, the exhaust gas discharged from each of the front cylinder 31a and the rear cylinder 31b bypasses the turbine 51 and is sent to the catalyst device 100.

  The second exhaust passage 132 is made of a sheet material. Thereby, the heat capacity of the second exhaust passage 132 is reduced. Therefore, when the catalyst device 100 is inactive, the exhaust gas can be sent to the catalyst device 100 while the temperature remains high. Thereby, early activation of the catalyst device 100 is achieved.

  Further, in the high-load and high-rotation region of the engine 1, the exhaust valve whose temperature has been lowered by passing through the turbine 51 is mixed with the exhaust gas that bypasses the turbine 51 by closing the bypass valve 133, so that the catalyst device 100. Sent to. Although there is a concern that the temperature of the exhaust gas sent to the catalyst device 100 becomes excessively high in the high-load high-rotation region of the engine 1, a part of the exhaust gas is passed through the turbine 51, so It becomes possible to prevent deterioration of the catalyst device 100 by lowering the temperature of the exhaust gas to be sent.

  The limiting unit is not limited to being configured by the VGT vane 54. For example, when the turbocharger is not VGT, an adjustment valve that can restrict the inflow of exhaust gas to the turbine 51 may be provided separately.

In the first exhaust passage 131, an O ₂ sensor 135 for cylinder identification is disposed downstream of the turbine 51 and upstream of a location where the second exhaust passage 132 is assembled.

In the multi-cylinder rotary piston engine 1, it is difficult to accurately identify a cylinder by using a single O ₂ sensor employed in a reciprocating engine, but the turbine in the first exhaust passage 131 is difficult to identify. As described above, the rotary piston is provided by disposing the O ₂ sensors 134 and 135 at the downstream side of 51 and the downstream side of the gathering location of the first exhaust passage 131 and the second exhaust passage 132, respectively. Also in the engine 1, cylinder identification is possible.

  The technique disclosed here is not limited to being applied to the two-cylinder rotary piston engine 1. Although illustration is omitted, the technique disclosed herein can be applied to, for example, a three-cylinder rotary piston engine. In this case, one of the three cylinders arranged in the center may be a first type cylinder, and two cylinders at both ends may be a second type cylinder. In this configuration, the exhaust ports of the first type cylinder are respectively formed in the two intermediate housings, and the exhaust ports of the second type cylinder are respectively formed in the two side housings. Note that there is one exhaust port for each cylinder of the second type.

1 Rotary piston engine (engine)
100 catalyst device 13 exhaust passage 131 first exhaust passage 132 second exhaust passage 1321 throttle 133 bypass valve (communication portion)
135 (for cylinder identification) O ₂ sensor 2 rotor 3 rotor housing 3a trochoid inner peripheral surface 31 rotor accommodating chamber (cylinder)
31a Front cylinder (first cylinder)
31b Rear cylinder (second cylinder)
41 Side housing 4 Intermediate housing (side housing)
5 Turbocharger 51 Turbine 54 Vane (restricted part)

Claims (5)

An engine configured to have a plurality of cylinders;
An exhaust passage configured to flow exhaust gas discharged from each of the plurality of cylinders;
A turbocharger configured to have a turbine disposed in the exhaust passage,
The engine is
A plurality of rotors corresponding to the plurality of cylinders;
A rotor housing configured to have a trochoid inner peripheral surface on which each of the plurality of rotors slides;
A side housing configured to partition the cylinder housing the rotor together with the rotor housing by being disposed between the rotor housings and on a side portion of the rotor housing;
An exhaust port that connects the cylinder and the exhaust passage is provided in the side housing, and is open to a side surface of the side housing so as to face the cylinder.
The plurality of cylinders are connected to a first type cylinder connected to the turbine through a first exhaust passage, and a second exhaust passage that gathers with the first exhaust passage downstream of the turbine. A second type of cylinder that bypasses the turbine,
The exhaust port of the first type cylinder is provided in each of the side housings on both sides of the rotor housing, and each exhaust port opens into the first type cylinder.
The exhaust port of the second type cylinder is provided in the side housing on one side of the rotor housing where the exhaust port of the first type cylinder is not provided, and in the second type cylinder. Open to
With the turbocharger, the sum of the cross-sectional areas of the exhaust ports per cylinder of the first type cylinder is greater than the sum of the cross-sectional areas of the exhaust ports per cylinder of the second type cylinder Rotary piston engine. The rotary piston engine with a turbocharger according to claim 1,
In the second exhaust passage, an opening end portion that gathers with the first exhaust passage on the downstream side of the turbine is substantially the same as the flow direction of the first exhaust passage. A rotary piston engine with a turbocharger provided adjacent to an opening end of an exhaust passage and provided with a throttle for reducing the passage area. The rotary piston engine with a turbocharger according to claim 1 or 2,
The second exhaust passage is a rotary piston engine with a turbocharger that is made of a sheet material. In the rotary piston engine with a turbocharger according to any one of claims 1 to 3,
Upstream of the turbine in the first exhaust passage,
A restricting portion configured to be able to restrict the inflow of exhaust gas to the turbine;
A communication portion configured to switch between a state communicating with the second exhaust passage and a state not communicating with the second exhaust passage upstream from the restriction portion; and
The exhaust gas discharged from the first type cylinder by the restricting portion when the catalytic device disposed downstream of the gathering location of the first exhaust passage and the second exhaust passage is inactive. Is restricted from flowing into the turbine, and the communication portion is in a communication state, thereby bypassing the turbine and sending the exhaust gas discharged from the first type cylinder to the second exhaust passage. Rotary piston engine with turbocharger. In the rotary piston engine with a turbocharger according to any one of claims 1 to 4,
In the first exhaust passage, a turbocharger-equipped rotary in which an O ₂ sensor for cylinder identification is disposed downstream of the turbine and upstream of a location where the second exhaust passage gathers. Piston engine.

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