JP2020084931A - Rotary piston engine - Google Patents

Abstract

To provide a rotary piston engine capable of improving combustion stability in a low rotation operation area.SOLUTION: A rotary piston engine includes: a rotor 3a; a rotor housing 5a; a side housing 6a and an intermediate housing 6c that are disposed at longitudinal both sides of the rotor 3a; first and second intake ports 11a, 12a formed on the side housing 6a; a first exhaust port 13a formed on the intermediate housing 6c, and disposed at the same side as the first and second intake ports 11a, 12a in a short axis direction on a cross-section orthogonal to a crank shaft; and a primary air supply mechanism 40 including a supply port 41a that is open to an operation chamber on the way of transition from an exhaust stroke to an intake stroke, and a supply passage 42 capable of supplying primary air to the supply port 41a. A first opening/closing valve 43a configured to open in a low rotation operation area and to close in a high rotation operation area higher than the low rotation area, is disposed on a branch passage 42a that is an intermediate portion of the supply passage 42.SELECTED DRAWING: Figure 1

Description

The present invention relates to a rotary piston engine, and more particularly to a rotary piston engine having an intake port and an exhaust port formed in a side housing.

Conventionally, a rotary piston engine (hereinafter, abbreviated as a rotary engine) including a side intake port formed in one side housing and a peripheral exhaust port formed in a rotor housing is known.
In such a rotary engine, when the working chamber changes from the working chamber that is the exhaust stroke (hereinafter, exhaust working chamber) to the working chamber that is the intake stroke (hereinafter, intake working chamber), the side intake port and the trailing Since there is an overlap period with the peripheral exhaust port located on the side, some of the exhaust gas is introduced into the intake working chamber as dilution gas through the gap between the inner peripheral surface of the rotor housing and the flank surface of the rotor. The phenomenon occurs.
When the dilution gas is brought into the intake working chamber, the intake air in the working chamber is diluted and combustion becomes unstable, which causes a problem that emission performance and fuel efficiency deteriorate.

Therefore, a technique for reducing the dilution gas existing in the working chamber has been proposed.
Although the in-cylinder injection engine with a mechanical supercharger of Patent Document 1 is not a rotary engine, it has an injector that directly injects fuel into the combustion chamber, a mechanical supercharger provided in the intake passage, and an intake distribution area. Adjustable intake air flow adjusting means is provided to hold the overlap period of the intake valve and the exhaust valve for a predetermined period during low rotation and low load operation, and the pressure of the intake passage during the held overlap period. The mechanical supercharger is driven so that it becomes higher than the pressure. As a result, residual exhaust gas in the combustion chamber is scavenged and combustion stability is improved.

Further, a dilution gas reduction technique that does not use the overlap period between the intake valve and the exhaust valve has been proposed.
The rotary engine of Patent Document 2 includes a side intake port, a peripheral exhaust port, an auxiliary intake port formed in the same side housing as the side intake port and opening earlier than the side intake port, and an opening portion of the auxiliary intake port. An air supply passage that connects to an air pump is provided, and during low-rotation low-load operation, secondary air as scavenging air is supplied from this air supply passage to the working chamber during the transition from the exhaust stroke to the intake stroke. This reduces the dilution gas flowing into the intake working chamber.

Japanese Patent Laid-Open No. 10-274069 JP-A-6-002560

The rotary engine of Patent Document 2 can reduce dilution gas without requiring a mechanical supercharger.
However, in the technique of Patent Document 2, there is a possibility that the combustion stability in a low rotation operation region such as idle may be reduced by supplying an air different from the primary air for combustion.
That is, since air is supplied to the auxiliary intake port by branching from the supply passage of the secondary air that is supplied to the vicinity of the peripheral exhaust port opening of the rotor housing and is not measured by the air flow meter, the air is supplied to the working chamber from the air pump. When the next air is supplied, there is a gap between the detected intake air amount for combustion detected by the air flow meter and the actual intake air amount that actually exists in the intake working chamber, so the air-fuel ratio has the desired value. It will be greatly deviated from and it will be easy to misfire.
When a misfire occurs, the exhaust pressure becomes lower than in normal combustion, and the amount of secondary air carried into the intake working chamber increases, so there is a fear of a vicious cycle in which the combustibility is further reduced.

It is also possible to use a mechanical supercharger to supply primary air for combustion as in the technique of Patent Document 1.
However, since the overlap structure of the intake valve (intake port) and the exhaust valve (exhaust port) is a prerequisite structure, the exhaust gas scavenged by the primary air may be offset by the exhaust gas brought in from the exhaust port. As expected, we cannot expect a sufficient scavenging effect.
Therefore, in the rotary engine, it is not easy to secure the combustion stability in the low rotation speed operation region.

An object of the present invention is to provide a rotary piston engine capable of improving combustion stability in a low rotation speed operation region.

The rotary piston engine according to claim 1 is a rotor rotatable around a crankshaft, a rotor housing surrounding the outer periphery of the rotor, and both sides of the rotor in the crankshaft direction, which cooperate with the rotor and the rotor housing. In a rotary piston engine including a pair of side housings that form a working chamber, an intake port formed in any one of the pair of side housings and any one of the pair of side housings. And, with respect to the short-axis direction in the cross section orthogonal to the crankshaft, an exhaust port provided on the same side as the intake port, a supply port opening to the working chamber in the process of transition from the exhaust stroke to the intake stroke, and the supply opening, A primary air supply mechanism having a primary air supply passage capable of supplying primary air for combustion via an intake air amount detection device for measuring the amount of intake air supplied to the working chamber, It is characterized in that a first opening/closing valve is provided in the middle of the primary air supply passage so as to be opened in a low rotation operation region and closed in a high rotation operation region higher than the low rotation operation region.

In this rotary piston engine, an intake port formed in any of the pair of side housings, and an intake port formed in any of the pair of side housings in the minor axis direction in the cross section orthogonal to the crankshaft. Since it has the exhaust port provided on the same side, the intake port and the exhaust port can be configured as a side port structure, and a part of the exhaust gas is taken in through the gap between the inner peripheral surface of the rotor housing and the flank surface of the rotor. It is possible to avoid a phenomenon brought into the working chamber.
Primary for combustion via a supply port that opens to the working chamber during the transition from the exhaust stroke to the intake stroke, and an intake air amount detection device that measures the amount of intake air supplied to the working chamber at the supply port Since the primary air supply mechanism having the primary air supply passage capable of supplying air is provided, the detected intake air amount for combustion detected is made to match the actual intake air amount actually existing in the intake working chamber. As a result, it is possible to prevent misfire due to the deviation of the air-fuel ratio.
Since the first opening/closing valve is provided in the middle of the primary air supply passage, the first on-off valve opens in the low rotation speed operation region and closes in the high rotation speed operation region higher than the low rotation speed operation region. The dilution gas in the room can be replaced with the primary air, and combustion stability can be improved.

According to a second aspect of the present invention, in the first aspect of the invention, the exhaust port includes a first exhaust port and a second exhaust port whose exhaust start timing is later than that of the first exhaust port, and the second exhaust port The supply port is formed in the port.
According to this configuration, the overlap period between the first exhaust port and the second exhaust port can be formed, and the dilution gas pressed by the primary air is discharged to the outside through the first exhaust port. be able to.

The invention of claim 3 is characterized in that, in the invention of claim 2, the first exhaust port is provided in the side housing, and the second exhaust port is provided in the rotor housing.
According to this configuration, the exhaust resistance can be reduced in the high rotation operation range, and high-speed traveling performance can be ensured.

According to a fourth aspect of the present invention, in the third aspect of the present invention, a second opening/closing valve that is openable/closable is provided downstream of the second exhaust port, and the second opening/closing valve is held in a closed state when primary air is supplied. It is characterized by that.
With this configuration, the introduction of the primary air can be improved by preventing the primary air from flowing out, and the dilution gas and the primary air can be reliably replaced.

According to a fifth aspect of the invention, in the third or fourth aspect of the invention, the side housing is arranged between the first and second rotors arranged in the crankshaft direction and the first and second rotors. An intermediate housing, a first side housing that faces the intermediate housing with the first rotor sandwiched between them, and a second side housing that faces the intermediate housing with the second rotor sandwiched between them. A first intake port and a second intake port that is disposed on the leading side of the first intake port and has a later closing timing are formed in the first side housing, and the first exhaust port of the first rotor and the second rotor are formed. A first intake port and a second intake port that is disposed on the leading side of the first intake port and has a later closing timing are formed in the intermediate housing, and the first exhaust port of the second rotor is the second side housing. It is characterized by being formed in.
According to this configuration, the intake late closing mechanism can be configured with a simple configuration, and fuel consumption can be improved. Further, in the two-rotor rotary piston engine, it is possible to achieve both thinning of the intermediate housing and reduction of dilution gas.

According to a sixth aspect of the present invention, in the first aspect of the present invention, the turbocharger is provided in the middle of the intake passage and supercharges the intake air into the working chamber in the intake stroke. It is characterized in that the supply port communicates with the downstream side intake passage of the supercharger.
With this configuration, the supply pressure of the primary air can be secured regardless of the operating state.

In the invention of claim 7, in the invention of claim 6, an intake control valve capable of controlling an intake flow rate is provided in a downstream side intake passage of the supercharger, and the primary air supply passage includes the supply port and the intake air. It is characterized by communicating with a position upstream of the control valve and downstream of the supercharger.
According to this configuration, the primary air can be reliably supplied to the working chamber even in the low rotation speed operation region.

According to the rotary piston engine of the present invention, it is possible to improve combustion stability in the low rotation speed operation region.

1 is a schematic configuration diagram of a rotary piston engine according to a first embodiment. It is a schematic side view when it sees from the left. It is a schematic longitudinal cross-sectional view when it sees from the front. It is a schematic cross-sectional view of an engine body. It is a figure showing a relation between an eccentric angle and an opening area of a port. FIG. 6 is an operation characteristic diagram showing opening/closing regions of first and second control valves. The internal states of the working chamber before and after the intake stroke in the low load operation region are as follows: (a) exhaust top dead center, (b) eccentric angle 630°, (c) eccentric angle 810°, (d) eccentric angle. It is a figure which shows the internal state in an angle of 1050 degrees. It is a graph which shows the pressure characteristic of primary air and exhaust air. The internal state of the working chamber before and after the exhaust stroke in the low load operation region, where (a) is an eccentric angle of 230°, (b) is an eccentric angle of 360°, (c) is an eccentric angle of 450°, and (d) is an eccentric angle. Angle 530°, (e) is a diagram showing an internal state at an eccentric angle 630°. FIG. 6 is an operating characteristic diagram showing an opening/closing region of an EGR valve.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The description of the preferred embodiments below is merely exemplary in nature and is not intended to limit the present invention, its application, or its application.

The first embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is a diagram schematically showing an overall configuration of a rotary piston engine (hereinafter abbreviated as engine) 100, and FIG. 2 is a schematic side view of the engine 100 when viewed from the left side, and FIG. FIG. 3 is a schematic vertical cross-sectional view of the engine 100 when viewed from the front.
The first and second intake ports 11a and 12a, which will be described later, are formed in the side housing 6a, the first exhaust port 13a is formed in the intermediate housing 6c, and the second exhaust port 14a is formed in the rotor housing 5a. 3, in order to clarify the relative opening/closing timing of each port 11a, 12a, 13a, 14a, each port 11a, 12a, 13a, 14a is shown on the same plane.
Hereinafter, in the drawings, the arrow F direction will be referred to as the front, the arrow L direction as the left, and the arrow U direction as the upper side, as appropriate.

As shown in FIGS. 1 to 3, the engine 100 includes an engine body 1 having two first and second rotor accommodating chambers 2a and 2b arranged in front and rear, and air introduced into each rotor accommodating chamber 2a and 2b. An intake passage 30 through which a mixture of air and fuel (hereinafter, referred to as intake air) flows, an exhaust passage 50 through which exhaust gas (hereinafter, referred to as exhaust gas) exhausted from each rotor accommodating chamber 2a, 2b flows, and turbocharging. A machine 60, an EGR device 70, etc. are provided.
The engine 100 is mounted on a vehicle that uses the engine body 1 as a drive source for traveling.

First, the engine body 1 will be described.
As shown in FIG. 3, the engine body 1 is provided with an eccentric shaft 4 which is an output shaft (crank shaft) that extends through the rotor housing chambers 2a and 2b and extends in the front-rear direction.
The rotors 3a and 3b are housed in the rotor housing chambers 2a and 2b of the engine body 1, respectively. Each rotor 3a, 3b is formed in a substantially triangular shape in a side view.
These rotors 3a and 3b are supported so as to make a planetary rotational movement with respect to the eccentric shaft 4, and the three tops thereof move around the eccentric shaft 4 so as to move along the inner peripheral surfaces of the rotor accommodating chambers 2a and 2b. It's spinning.
The member configuration on the second rotor accommodating chamber 2b side is substantially the same as the member configuration on the first rotor accommodating chamber 2a side, except for some differences, and therefore, unless otherwise specified, the first rotor accommodating chamber 2a will be described below. The member configuration on the side will be mainly described.

Apex seals 7 extending in the front-rear direction are attached to the tops of the rotors 3a, and substantially cylindrical corner seals 8 are provided at both front and rear ends of each apex seal 7.
On both the front and rear side surfaces of the rotor 3a, side seals 9 that connect adjacent corner seals 8 to each other in substantially parallel to the outer peripheral edge of the rotor 3a, and the center of the rotor 3a on the radially inner side of the side seals 9 than the side seals 9 are formed. There are provided two large and small annular oil seals 10 centering on the.

FIG. 4 is a schematic cross-sectional view of the engine body 1 in the direction parallel to the crankshaft.
For convenience of explanation, FIG. 4 is not an accurate sectional view, but schematically shows the ports 11a, 11b, 12a, 12b, 13a, 13b, 14a, 14b, etc. on the same plane.
As shown in FIGS. 2 and 4, the engine body 1 includes rotor housings 5a and 5b that surround the outer circumferences of the rotors 3a and 3b, and side housings 6a and 5a that are provided in front of the rotor 3a and behind the rotor 3b, respectively. 6b, an intermediate housing (also referred to as an intermediate housing) 6c interposed between the rotor 3a and the rotor 3b, and the like.
The first and second rotor accommodating chambers 2a and 2b are partitioned by rotor housings 5a and 5b, side housings 6a and 6b, and an intermediate housing 6c.
The intermediate housing 6c corresponds to the side housing on the rear side of the rotor 3a and the side housing on the front side of the rotor 3b.

Inner peripheral surfaces of the first and second rotor housings 5a and 5b extend along a parallel trochoidal curve, and the first and second rotor accommodating chambers 2a and 2b are divided into three working chambers by the rotors 3a and 3b while the vehicle is traveling. It is divided into each. In such an engine 100, the three working chambers move around the eccentric shaft 4 as the rotors 3a and 3b rotate, and in each working chamber, each stroke of four cycles of intake, compression, expansion (combustion) and exhaust is performed. Is being done.
Each stroke of one cycle is performed in a period in which the eccentric shaft 4 rotates 270°.

Since the rotors 3a and 3b are rotated with a phase difference of 180° with respect to the rotation angle of the eccentric shaft 4 (hereinafter referred to as eccentric angle), the rotor accommodating chambers 2a and 2b are displaced by 180° with respect to the eccentric angle. , Compression, expansion and exhaust strokes are performed respectively.
As indicated by the arrow in FIG. 3, the rotor 3a rotates clockwise, the intake stroke is generally performed in the upper left region, the compression stroke is generally performed in the upper right region, and the expansion stroke is generally performed in the lower right region. The exhaust stroke is generally performed in the lower left region.

As shown in FIG. 3, in the rotor housing 5a, a leading-side ignition plug (hereinafter referred to as an L-side plug) 21a (hereinafter referred to as an L-side plug) 21a arranged at a position near the compression top dead center of the right side wall portion, and this L Trailing side ignition plugs (hereinafter, referred to as T side plugs) 21b (trailing side ignition means) arranged at the trailing side positions of the side plugs 21a are mounted respectively.

Next, the first and second intake ports 11a and 12a will be described.
As shown in FIGS. 1, 3, and 4, the first and second intake ports 11a and 12a are configured as side intake ports in the upper left area of the side housing 6a.
These first and second intake ports 11a and 12a are closely arranged so as to be adjacent to each other along the rotation direction of the rotor 3a, and the first intake port 11a on the lower left side in the intake stroke is more than the second intake port 12a on the upper right side. Is also configured to close early.
As a result, the second intake port 12a constitutes an intake late closing mechanism to reduce pumping loss in the low load operation region.

The first intake port 11a has a substantially triangular opening with respect to the working chamber, which is the intake stroke of the rotor accommodating chamber 2a, and is formed so as to extend from this port opening in a substantially straight line to the left in the horizontal direction. ing. The second intake port 12a has a substantially rhombus-shaped opening with respect to the working chamber, which is the intake stroke of the rotor accommodating chamber 2a, and is formed so as to extend substantially linearly from the port opening toward the upper left side. ing.

As shown in FIG. 3, the axial center L1 of the first intake port 11a and the axial center L2 of the second intake port 11b intersect at an acute angle and at the upstream side of each port, in other words, from the eccentric shaft 4. The distance between the two is increased as the distance to the outside in the radial direction increases.
Hereinafter, the working chambers in the intake, compression, expansion, and exhaust strokes formed in the rotor accommodating chamber 2a will be simply referred to as an intake working chamber, a compression working chamber, an expansion working chamber, and an exhaust working chamber, respectively. And

As shown in FIGS. 2 and 3, the side housing 6a is provided with first and second injectors 23a and 24a for supplying fuel to the intake working chamber, respectively, on substantially the same circumference.
The first injector 23a is arranged at a position corresponding to an area between the first and second intake ports 11a and 12a so as to be inclined leftward and upward, and its injection port is directed toward the port opening of the first intake port 11a. Is arranged in the vicinity of.
The second injector 24a is arranged substantially vertically in the right side portion of the second intake port 12a, and is arranged in the vicinity of the port opening so that its injection port faces the port opening of the second intake port 12a.
The first and second injectors 23a and 24a are respectively connected to the front end portions of the delivery pipes 25 extending in the front-rear direction, and attached to the mounting boss portions formed in the vicinity of the respective port openings.
The delivery pipe 25 is supplied with pressurized fuel from a fuel tank via a supply passage (all not shown).

FIG. 5 is a diagram showing the relationship between the eccentric angle and the opening area of the port.
As shown in FIG. 5, the first intake port 11a opens into the intake working chamber near the exhaust top dead center (for example, 550°), and closes at a time when the intake bottom dead center is slightly exceeded (for example, 830°). ..
Like the first intake port 11a, the second intake port 12a opens into the intake working chamber near the exhaust top dead center, and is retarded from the intake bottom dead center and retarded from the first intake port 11a. It is closed (for example, 910°).
The ignition timing of the L-side plug 21a that performs main combustion is set to, for example, 1050°, and the ignition timing of the T-side plug 21b that performs secondary combustion is set to, for example, 1065°.

The first and second intake ports 11b and 12b corresponding to the rotor accommodating chamber 2b and the first and second injectors 23b and 24b for supplying fuel to the intake working chamber are respectively formed on substantially the same circumference of the intermediate housing 6c. ing. The first and second intake ports 11b and 12b and the first and second injectors 23b and 24b are formed in the intermediate housing 6c, except for the first and second intake ports 11a and 12a, the first and second intake ports. The two injectors 23a and 24a have substantially the same configuration.

Next, the first and second exhaust ports 13a and 14a will be described.
As shown in FIGS. 1, 3, and 4, the first exhaust port 13a is configured as a side exhaust port in the lower left area of the intermediate housing 6c. The first exhaust port 13a is arranged at a position opposite to the first and second intake ports 11b and 12b with respect to the rotor 3a, that is, in a staggered arrangement with the first and second intake ports 11b and 12b with the so-called rotor 3a interposed therebetween. It is installed in.
The first exhaust port 13a has a substantially triangular opening with respect to the exhaust working chamber, and is formed to extend leftward from this port opening.

The second exhaust port 14a is configured as a peripheral exhaust port in the lower left area of the rotor housing 6a. The second exhaust port 14a is formed to open later than the first exhaust port 13a.
The second exhaust port 14a has a substantially rectangular opening with respect to the exhaust working chamber, and is formed so as to extend in a substantially straight line from the port opening to the left.
The front-rear dimension of the second exhaust port 14a is set to about 80% of the front-rear dimension of the rotor housing 6a. As a result, the soot accumulated near the outer peripheral edge of the rotor housing chamber 2a is discharged from the second exhaust port 14a to the outside of the rotor housing chamber 2a.

As shown in FIG. 5, the first exhaust port 13a opens to the exhaust working chamber at a timing (eg, 230°) that is more advanced than the expansion bottom dead center, and closes to near exhaust top dead center (eg, 530°). ..
The second exhaust port 14a opens to the exhaust working chamber near the expansion bottom dead center (for example, 270°), is retarded from the exhaust top dead center, and is opened later than the opening timing of the first and second intake ports 11a and 12a. It is closed at the retard side (for example, 630°).
In the present embodiment, the opening period of the first exhaust port 13a and the opening periods of the first and second intake ports 11a and 12a do not overlap with each other, and the opening period of the second exhaust port 14a and the first and second intake ports are not overlapped. The opening periods of 11a and 12a are overlapped.
Thereby, the exhaust gas (residual gas after combustion) in the intake working chamber is pushed toward the second exhaust port 14a side by the intake air that has flowed in from the first and second intake ports 11a and 12a, and the scavenging property is enhanced.

The first exhaust port 13b corresponding to the rotor housing chamber 2b is formed in the side housing 6b, and the second exhaust port 14b is formed in the rotor housing 6b.
The first exhaust port 13b is configured substantially the same as the first exhaust port 13a except that it is formed in the side housing 6b, and the second exhaust port 14b is formed in the rotor housing 6b. The second exhaust port 14a has substantially the same configuration.

Next, the intake passage 30 will be described.
As shown in FIG. 1, the intake passage 30 includes an upstream intake passage 31, a downstream intake passage 32 connected to the downstream end of the upstream intake passage 31, and passage portions 33a and 33b.
In the upstream intake passage 31, an air cleaner 34, an air flow meter 35 (intake air amount detection device) for measuring the amount of intake air, a compressor 61 of the turbocharger 60, an intercooler 36, in order from the upstream side. A throttle valve 37 for controlling the amount of intake air, a surge tank 38, etc. are provided.

An upstream side portion of the downstream side intake passage 32 is inserted into the surge tank 38, and a downstream side portion is branched into two passage portions 32a and 32b.
These passage portions 32a and 32b are independently connected to the first intake port 11a of the rotor housing chamber 2a and the first intake port 11b of the rotor housing chamber 2b, respectively.
The passage portions 33a and 33b have their upstream portions inserted into the surge tank 38 and are independently connected to the second intake port 12a of the rotor housing chamber 2a and the second intake port 12b of the rotor housing chamber 2b. ..

The downstream intake passage 32 and the passage portions 33a and 33b are configured by an intake manifold that communicates with the downstream end of the upstream intake passage 31 via a surge tank 38.
The flange portion formed at the downstream end of the passage portion 32a is connected to the left vertical wall portion of the side housing 6a via a fastening member, and the flange portion formed at the downstream end of the passage portion 33a is located on the left side of the side housing 6a. It is connected to the upper inclined wall portion via a fastening member.

A mounting boss portion is formed between the flange portion of the passage portion 32a and the flange portion of the passage portion 33a, and the first injector 23a is attached thereto. The second injector 24a is attached to a mounting boss portion formed on the right side of the flange portion of the passage portion 33a.
Similarly, the first injector 23b is mounted on a mounting boss portion between the flange portion of the passage portion 32b and the flange portion of the passage portion 33b, and the second injector 24b is formed on the right side of the flange portion of the passage portion 33b. It is attached to the mounting boss.
As a result, the injectors can be arranged near the openings of the first and second intake ports 11a and 12a, and the acceleration response at low speed traveling is improved.
Further, the first injector 23b closest to the first exhaust port 13a, which is a heat source, is separated from the first exhaust port 13a via the first intake port 11b to avoid heat damage such as vapor. ..

A single first control valve 34 capable of controlling opening/closing of the first intake ports 11a, 11b is provided in the middle of the downstream side intake passage 32 corresponding to between the passage portions 32a, 32b and the surge tank 38. There is. Second control valves 35a and 35b capable of opening and closing the second intake ports 12a and 12b are provided in the passage portions 33a and 33b, respectively, in the vicinity of the second intake ports 12a and 12b.
FIG. 6 is an operation characteristic diagram showing the open/close areas of the control valves 34, 35a, 35b.
As shown in FIG. 6, in the low load operation region A1 where the load is set to 200 Nm or less, the first control valve 34 is closed and the second control valves 35a and 35b are open.

This is for the following reason.
FIG. 7 is a diagram showing the internal state of the working chamber before and after the intake stroke in the low load operation region, which is shown with a higher concentration in the higher temperature region.
As shown in FIG. 7(a), when the working chamber changes from the exhaust stroke to the intake stroke, residual exhaust remaining in the dead volume between the inner peripheral surface of the rotor housing 5a and the flank surface of the rotor 3a Gas) is brought into the intake working chamber.
Then, as shown in FIGS. 7B and 7C, since the intake air (white arrow) is introduced into only the second intake port 12a on the leading side into the intake working chamber, the dilution existing in the working chamber is performed. Gas is forcibly moved from the leading area to the trailing area.

Finally, as shown in FIG. 7D, the intake air staying in the vicinity of the L-side plug 21a is ignited, and its flame propagates to the trailing side heated by the dilution gas.
Further, the T-side plug 22a is ignited after the ignition of the L-side plug 21a which is the main combustion.
As a result, secondary combustion is performed in which unburned gas left unburned in the main combustion is burned.
That is, by moving the dilution gas in the working chamber to the trailing side by using the intake air introduced from the second intake port 12a, the leading side region of the working chamber is brought into a state suitable for stable combustion and The area on the trailing side of the chamber is in a state suitable for unburned gas reduction processing.

Further, as shown in FIG. 6, in the high load operation region A2 below the full load except the low rotation operation region, the first control valve 34 and the second control valves 35a, 35b are all opened.
As a result, the intake air amount is secured and the output torque of the engine 100 is secured.
In the low rotation and high load operation region A3, the first control valve 34 is open and the second control valves 35a and 35b are closed.
This reduces the exhaust gas blown back toward the second intake ports 12a and 12b, which are late closing ports, during the low rotation and high load operation.
As described above, in the present embodiment, the main intake port of the engine 100 is configured not by the first intake ports 11a, 11b formed on the trailing side but by the second intake ports 12a, 12b formed on the leading side. is doing.

As shown in FIGS. 1, 3, and 4, a primary air supply mechanism 40 capable of supplying primary air for combustion to the working chamber in the transition from the exhaust stroke to the intake stroke is formed in the intake passage 30. ing.
The primary air supply mechanism 40 is provided between the compressor 61 and the intercooler 36, and the supply ports 41a and 41b respectively formed in the rotor housings 5a and 5b and opening to the working chambers during the transition from the exhaust stroke to the intake stroke. A supply passage 42 and the like are provided, which connect the corresponding intermediate portion of the upstream intake passage 31 and the supply ports 41a and 41b via branch passages 42a and 42b, respectively.
The supply ports 41a and 41b are formed in the middle of the second exhaust ports 14a and 14b, respectively, and open to the working chamber for the same period as the opening period of the second exhaust ports 14a and 14b. The supply ports 41a and 41b are respectively configured so that the traveling direction of the primary air introduced into the working chamber blocks the progress of dilution gas brought into the leading region.

On-off valves 43a and 43b (first on-off valves) are provided in the middle of the branch passages 42a and 42b, respectively. These on-off valves 43a and 43b are one-way valves (reverse valves) that allow introduction of primary air into the working chamber when the primary air is higher than the working chamber pressure (so-called exhaust pressure) by a predetermined pressure (for example, 0.03 atmospheric pressure) or more. It is composed of a tributary valve or a check valve).

As shown in FIG. 8, the pressure of the primary air flowing through the branch passages 42a and 42b and the pressure of the exhaust air in the working chamber have a characteristic that they increase linearly as the number of revolutions increases when the vehicle runs at medium and low speeds.
Since the exhaust pressure has a higher rate of increase than the primary air pressure, the primary air pressure is higher than the exhaust pressure up to 3000 rpm, but thereafter, the exhaust pressure reverses the primary air pressure.
Therefore, the on-off valves 43a and 43b generally operate to open in a low rotation speed operating range equal to or lower than the set rotation speed (3000 rpm) and generally close to operate in a high rotation speed operating range higher than the set rotation speed.
As a result, the primary air, which is a part of the detected intake air amount measured by the air flow meter 35, is used to prevent the dilution gas from advancing in the leading direction, and at the same time, the dilution gas and the primary gas in the working chamber It replaces air to stabilize combustion.

Next, the exhaust passage 50 will be described.
As shown in FIG. 1, the exhaust passage 50 has first exhaust passages 51a and 51b connected to the two first exhaust ports 13a and 13b, and branch passages 52a and 52b to the two second exhaust ports 14a and 14b. The second exhaust passage 52 and the like are connected via the.
The turbine 62 of the turbocharger 60 is connected to the first exhaust passages 51a and 51b, respectively. The second exhaust passage 52 bypasses the turbine 62 and communicates with an intermediate portion of the downstream exhaust passage 53 on the downstream side of the turbine 62. In the downstream side portion of the downstream side exhaust passage 53, for example, a purifying device 54 such as a three-way catalyst is provided.
The turbine 62 of this embodiment is a twin scroll turbine, and the first exhaust ports 13a and 13b are connected to the intake passages of the turbine 62 via the first exhaust passages 51a and 51b, respectively.

As shown in FIGS. 1, 3 and 4, exhaust opening/closing valves 55a and 55b (second opening/closing valves) that can be opened and closed are provided in the branch passages 52a and 52b, respectively.
The exhaust opening/closing valves 55a and 55b are normally maintained in an open state, allow exhaust gas flowing downstream from the exhaust working chamber via the second exhaust ports 14a and 14b, and supply primary air when primary air is supplied. It is configured to be closed in synchronization with the opening operation of the air supply on-off valves 43a and 43b.

FIG. 9 is a diagram showing the internal state of the working chamber before and after the exhaust stroke in the low load operation region, where the higher temperature region is shown with a darker concentration.
As shown in FIG. 9A, the second exhaust port 14a and the working chamber are not communicated with each other at the discharge start timing when the exhaust is discharged from the first exhaust port 13a.
As shown in FIGS. 9B to 9D, when the first exhaust port 13a is in the open state, the working chamber is read through the second exhaust port 14a as the working chamber changes (rotation of the rotor 3a). Since the primary air is supplied to the side region, the residual exhaust gas existing in the working chamber is forcibly discharged from the opened first exhaust port 13a and replaced with the primary air.
The exhaust on-off valve 55a is maintained in the closed state when the on-off valve 43a is in the open state, so that the primary air does not flow to the branch passage 52a side.
As shown in FIG. 9(e), since the valve closing timing of the second exhaust port 14a is later than the valve closing timing of the first exhaust port 13a, the intake operation is performed with the primary air replaced with the dilution gas. Brought to the room.

Next, the EGR device 70 will be described.
As shown in FIG. 1, since the EGR device 70 recirculates a part of the exhaust gas to the intake air, the EGR passage 71 that connects the exhaust passage 50 and the intake passage 30 with each other, the EGR valve 72 that opens and closes the EGR passage 71, and the exhaust gas The EGR cooler 73 etc. which cool a certain EGR gas are provided.
As shown in FIG. 10, the EGR valve 72 operates so as to supply the EGR gas to the working chamber in the high rotation speed operation range A4 and the low/medium rotation load operation range A5.
In particular, in the low/medium rotation operation region, the lower the rotation speed, the narrower the EGR gas supply regions on the low load side and the high load side are set.

The EGR passage 71 connects the intermediate portion of the downstream intake passage 32, which corresponds to the upstream side of the passage portions 32a and 32b and the downstream side of the first control valve 34, and the downstream exhaust passage 53.
As a result, as shown by the black arrow in FIG. 7B, during the low rotation operation in which the first control valve 34 is in the closed state, the closing timing is early and the first intake port in which the blowback from the rotor accommodating chamber 2a hardly occurs. An appropriate amount of EGR gas is introduced into the working chamber from 11a.
Further, by connecting the downstream end of the second exhaust passage 52 to the middle of the EGR passage 71, the EGR gas having a low temperature is supplied to the working chamber.

Since the temperature and the pressure of the exhaust gas of the second exhaust passage 52 are low, the differential pressure across the EGR passage 71 cannot be secured, and there is a possibility that the EGR gas cannot be supplied to the working chamber depending on the operating conditions.
Therefore, an exhaust control valve 74 is provided between the confluence of the EGR passage 71 and the second exhaust passage 52 and the downstream exhaust passage 53.
For example, when the engine load is equal to or less than the preset EGR reference load, the exhaust control valve 74 is controlled to the valve closing side, and its opening is set according to the intake pressure.
The exhaust control valve 74 is fully closed when the exhaust opening/closing valves 55a and 55b are closed, in other words, when the opening/closing valves 43a and 43b are open.
This is to prevent intake air from being introduced from the downstream intake passage 32 into the downstream exhaust passage 53.

In the present embodiment, an ECU (not shown) capable of controlling each part of the engine 100 is installed in the vehicle, and the injectors 23a, 23b, 24a, 24b, the first control valve 34, and the second control valves 35a, 35b are installed by this ECU. The throttle valve 37, the exhaust opening/closing valves 55a and 55b, the EGR valve 72, the exhaust control valve 74, etc. are controlled.
Further, the ECU obtains the air filling efficiency of the intake working chamber based on, for example, the intake air amount measured by the air flow meter 35, the rotation speed of the engine 100, the intake temperature, and the like, and the injectors 23a and 23b are determined from the air filling efficiency. , 24a, 24b are used to calculate the fuel injection amount.

Next, the operation and effect of the rotary piston engine 100 will be described.
According to the engine 100 of the first embodiment, the first and second intake ports 11a and 12a formed in the side housing 6a and the first and second intake ports 11a and 12a formed in the intermediate housing 6c in the minor axis direction in the crankshaft orthogonal cross section. Since the first exhaust port 13a is provided on the same side as the two intake ports 11a and 12a, the first and second intake ports 11a and 12a and the first exhaust port 13a can be configured as a side port structure, and the rotor housing 5a It is possible to avoid a phenomenon in which a part of the exhaust gas is brought into the intake working chamber through the gap between the inner peripheral surface of the rotor and the flank surface of the rotor 3a.
Since the primary air supply mechanism 40 having the supply port 41a opening to the working chamber on the way of the transition from the exhaust stroke to the intake stroke and the supply passage 42 capable of supplying the primary air for combustion to the supply opening 41a is detected. By matching the detected intake air amount for combustion with the actual intake air amount actually present in the intake working chamber, it is possible to prevent misfiring due to the deviation of the air-fuel ratio.
Since the first opening/closing valve 43a is provided in the branch passage 42a corresponding to the middle portion of the supply passage 42 so as to be opened in the low rotation operation region and closed in the high rotation operation region higher than the low rotation operation region, during the low rotation operation. The dilution gas in the intake working chamber can be replaced with the primary air, and the combustion stability can be improved.

The exhaust port includes a first exhaust port 13a and a second exhaust port 14a whose exhaust start timing is later than that of the first exhaust port 13a, and a supply port 41a is formed in the second exhaust port 14a. Thereby, the overlap period between the first exhaust port 13a and the second exhaust port 14a can be formed, and the dilution gas pressed by the primary air is discharged to the outside through the first exhaust port 13a. be able to.

Since the first exhaust port 13a is provided in the intermediate housing 6c and the second exhaust port 14a is provided in the rotor housing 5a, it is possible to reduce exhaust resistance in a high rotation operation region and ensure high-speed traveling performance.

An exhaust opening/closing valve 55a that can be opened/closed is provided downstream of the second exhaust port 14a. Since the exhaust opening/closing valve 55a is kept in a closed state when the primary air is supplied, it is possible to prevent the primary air from flowing out. The introduction property of the secondary air can be enhanced, and the dilution gas and the primary air can be reliably replaced.

First and second rotors 3a and 3b arranged side by side, an intermediate housing 6c arranged between the first and second rotors 3a and 3b, and a side facing the intermediate housing 6c with the first rotor 3a interposed therebetween. It has a housing 6a and a side housing 6b that faces the intermediate housing 6c with the second rotor 3b interposed therebetween, and is arranged on the first intake port 11a of the first rotor 3a and on the leading side of the first intake port 11a and closed. The second intake port 12a whose timing is late is formed in the side housing 6a, and is arranged on the leading side of the first exhaust port 13a of the first rotor 3a and the first intake port 11b of the second rotor 3b and the first intake port 11b. The second intake port 12b whose opening timing is late is formed in the intermediate housing 6c, and the first exhaust port 13b of the second rotor 3b is formed in the side housing 6b.
As a result, the intake late closing mechanism can be configured with a simple configuration, and fuel consumption can be improved. Further, in the two-rotor rotary piston engine 100, it is possible to achieve both thinning of the intermediate housing 6c and reduction of dilution gas.

There is a supercharger 60 arranged in the middle of the upstream intake passage 31 for supercharging intake air into the working chamber of the intake stroke, and the supply passage 42 corresponds to the supply port 41a and the downstream side of the supercharger 60. Since it communicates with the middle part of the upstream side intake passage 31, it is possible to secure the supply pressure of the primary air regardless of the operating state.

A throttle valve 37 capable of controlling the intake flow rate is provided in the middle of an upstream intake passage 31 corresponding to the downstream side of the supercharger 100. The supply passage 42 is upstream of the supply port 41a and the throttle valve 37 and is supercharger. Since it communicates with a position downstream of 100, the primary air can be reliably supplied to the working chamber even in the low rotation speed operation region.

Next, a modified example in which the above embodiment is partially modified will be described.
1] In the above-described embodiment, an example of a two-rotor rotary piston engine has been described, but a one-rotor rotary piston engine may be used, and a rotary piston engine of three or more rotors may be applied.

2] In the above-described embodiment, an example in which the first exhaust port is formed in a staggered manner on the side housing opposite to the side housing on which the first intake port is formed has been described. It may be formed in the same side housing as the side housing in which is formed.
Further, although the example in which the exhaust port structure is configured by the side exhaust port and the peripheral exhaust port has been described, it may be formed only by the side exhaust port, or conversely, may be formed by only the peripheral exhaust port.

3] In the above-described embodiment, the example in which the primary air supply port is formed in the second exhaust port which is the peripheral exhaust port has been described, but at least the same as the intake port and the exhaust port in the minor axis direction in the crankshaft orthogonal cross section. On the side and between the intake port and the exhaust port, the primary air supply port may be formed independently of the exhaust port.

4] In addition, those skilled in the art can carry out the present invention in a form in which various modifications are added to the above-described embodiment or in a form in which the respective embodiments are combined without departing from the spirit of the present invention. Such modifications are also included.

4 eccentric shaft 3a, 3b rotor 5a, 5b rotor housing 6a, 6b side housing 6c intermediate housing 11a, 11b first intake port 12a, 12b second intake port 13a, 13b first exhaust port 14a, 14b second exhaust port 31 upstream Side intake passage 35 Air flow meter 40 Primary air supply mechanisms 41a, 41b Supply ports 42a, 42b Branch passages 43a, 43b Open/close valves 55a, 55b Exhaust open/close valve 100 Engine

Claims (7)

A rotor rotatable around a crankshaft, a rotor housing surrounding the outer periphery of the rotor, and a pair of rotors arranged on both sides of the rotor in the crankshaft direction and forming a working chamber in cooperation with the rotor and the rotor housing. In a rotary piston engine with a side housing of
An intake port formed in any of the pair of side housings;
An exhaust port formed on any one of the pair of side housings and provided on the same side as the intake port in the minor axis direction of the crankshaft orthogonal cross section;
Primary for combustion via a supply port that opens to the working chamber during the transition from the exhaust stroke to the intake stroke, and an intake air amount detection device that measures the amount of intake air supplied to the working chamber at the supply port A primary air supply mechanism having a primary air supply passage capable of supplying air,
A rotary piston engine provided with a first opening/closing valve that opens in a low rotation speed operation region and closes in a high rotation speed operation region higher than the low rotation speed operation region in the middle of the primary air supply passage. .. The exhaust port includes a first exhaust port and a second exhaust port whose exhaust start timing is later than that of the first exhaust port,
The rotary piston engine according to claim 1, wherein the supply port is formed in the second exhaust port. The rotary piston engine according to claim 2, wherein the first exhaust port is provided in the side housing, and the second exhaust port is provided in the rotor housing. A second on-off valve that can be opened and closed is provided downstream of the second exhaust port,
The rotary piston engine according to claim 3, wherein the second on-off valve is held in a closed state when primary air is supplied. First and second rotors arranged in the crankshaft direction,
An intermediate housing as the side housing disposed between the first and second rotors,
A first side housing facing the intermediate housing with the first rotor interposed therebetween;
A second side housing facing the intermediate housing with the second rotor interposed therebetween;
A first intake port of the first rotor and a second intake port that is disposed closer to the leading side than the first intake port and has a late closing timing are formed in the first side housing;
A first exhaust port of the first rotor, a first intake port of the second rotor, and a second intake port that is arranged closer to the leading side than the first intake port and has a late closing timing are formed in the intermediate housing;
The rotary piston engine according to claim 3 or 4, wherein the first exhaust port of the second rotor is formed in the second side housing. It has a supercharger arranged in the middle of the intake passage to supercharge intake air into the working chamber of the intake stroke,
The rotary piston engine according to claim 1, wherein the primary air supply passage communicates the supply port with a downstream intake passage of the supercharger. An intake control valve capable of controlling the intake flow rate is provided in the intake passage on the downstream side of the supercharger,
7. The rotary piston engine according to claim 6, wherein the primary air supply passage communicates the supply port with a position upstream of the intake control valve and downstream of the supercharger.