JPH0337014B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for a rotary piston engine, and more specifically, the present invention relates to an intake system for a rotary piston engine. This relates to an engine that uses intake pressure waves generated within the engine to obtain a supercharging effect at high and medium engine speeds.

In general, a side intake port type two-cylinder rotary piston engine with two intake passages and variable ports consists of a rotor housing having a two-bar trochoidal inner circumferential surface and side housings located on both sides of the rotor housing. A substantially triangular rotor disposed in each of the formed casings is supported by an eccentric shaft and rotates planetarily with a phase difference of 180 degrees at the rotation angle of the shaft, and a throttle is applied to each cylinder. A first intake passage and a second intake passage each having a valve and provided independently in each of the side housings have a fixed opening period.
It opens into the working chamber through a second intake port whose opening period changes depending on the intake port and the control valve, and it maintains the above 180° phase difference between the two cylinders while adjusting the rotation of the rotor in each cylinder. Accompanied by inspiration,
Compression, explosion, expansion, and exhaust steps are performed in sequence. The second intake port is composed of a main port that is always open, and an auxiliary port that closes later than the main port and is opened and closed by a control valve, and when the control valve is closed, the engine is under low load. By supplying intake air only from the above-mentioned main port in the low and medium speed range of the engine, combustion stability is ensured by preventing intake air blowback. ,
By supplying intake air from the auxiliary port,
This is designed to increase filling efficiency and improve output.

By the way, it is well known that conventionally, in such a rotary piston engine, a supercharger is installed in the intake passage to supercharge the intake air, thereby increasing the charging efficiency and increasing the output. However, since it requires a supercharger, the structure becomes large-scale and costs increase.

In addition, conventionally, as a technique for obtaining a supercharging effect using intake pressure waves, as disclosed in Japanese Utility Model Publication No. 45-2321, in a single-cylinder rotary piston engine, the intake pipe is divided into two passages of different sizes. The engine is divided into two sections, each with a separate intake port, and when the engine is running at high speeds, two intake passages are used, and when the engine is running at low speeds, the intake passage that is at the later closing position is closed, and the intake air is blocked earlier. , which utilizes the supercharging effect due to intake air blockage at the point of maximum intake pressure, which is a function of intake pipe dimensions and engine speed, to obtain suitable charging efficiency over a wide range of engine speeds. Proposed. But this one is
It was designed for a single-cylinder rotary piston engine, and it was not clear how to utilize the intake pressure waves generated in the intake passage, and its structure and operation were not clear, so it could not be put into practical use right away.
Moreover, since a peripheral port is used as the intake port, the intake port communicates with the exhaust working chamber before the intake working chamber closes, and a supercharging effect can be obtained by blowing back exhaust gas from the exhaust working chamber. was difficult. In particular, in recent years commercially available cars, engine exhaust pressure has increased to reduce noise and purify exhaust gas.
The pressure is about 400 to 600 mmHg (gauge pressure), and in a turbocharged engine it is more than 1000 mmHg, making it impossible to expect improvement in charging efficiency by the peripheral port method.

Therefore, when examining the intake characteristics of the side intake port in a rotary piston engine, the present inventors found that (i) when the intake port is opened, the intake air is compressed by the pressure of the residual exhaust gas in the working chamber, and the air inside the intake passage is compressed. Compression waves are generated at the intake port (ii) It was discovered that when the intake port is closed, the intake air is compressed due to the inertia of the intake air, and compression waves are generated at the intake port in the intake passage. From this, the above for one cylinder
(i) If the compression wave when the intake port opens is applied to the intake port of the other cylinder, especially just before the intake port is fully closed, where intake air blowback occurs, an effective supercharging effect can be obtained (hereinafter referred to as the exhaust interference effect). ), and that a supercharging effect can be effectively obtained by applying the compression wave when the intake port of (ii) above in one cylinder is closed to the intake port of the other cylinder just before it is fully closed (hereinafter, They discovered this effect (called the inhalation inertia effect). Among these, the above-mentioned exhaust interference effect is caused by the increase in exhaust pressure due to the installation of catalyst devices for exhaust purification in engine exhaust systems in recent years, as mentioned above.
The effect is remarkable.

Note that, unlike the side intake port type, in the peripheral intake port type in which the intake passage opens into the rotor housing, the above effect does not occur because the intake port always opens into the working chamber.

That is, the present invention provides a side intake port type two-cylinder rotary piston engine equipped with two intake passages and variable ports as described above.
The opening period of each intake port, the opening operation area of the control valve,
By appropriately setting the communication position of each intake passage of both cylinders and the passage length between each intake port of both cylinders, exhaust interference in the intake system on the variable port side can be prevented at high engine speeds of 5000 to 7000 rpm. In addition to obtaining a supercharging effect due to the intake inertia effect in the intake system on the fixed port side, when the engine rotates at medium speeds of 3000 to 4500 rpm, a supercharging effect is obtained due to the exhaust interference effect in the intake system on the variable port side. The purpose is to effectively improve output by increasing charging efficiency at high and medium speeds of the engine by simply changing the design of the existing intake system without using a supercharger or the like. It is.

In order to achieve this objective, the configuration of the present invention is as follows:
A substantially triangular rotor is disposed in each casing, which is formed by a rotor housing having a nodular trochoidal inner circumferential surface and side housings located on both sides of the rotor housing, and is supported by an eccentric shaft, and the rotation of the shaft is supported by an eccentric shaft. The first intake passage and the second intake passage, each having a planetary rotation movement with a phase difference of 180° at the corner and each having a throttle valve for each cylinder, are independently provided in each side housing and have a fixed opening period. In a two-cylinder rotary piston engine that opens into the working chamber through a first intake port that is opened and closed and a second intake port whose opening period changes depending on the opening and closing of a control valve, a. It consists of a port and an auxiliary port that closes later than the main port and is opened and closed by a control valve, and its opening period is θl, and θh is the rotation angle of the eccentric shaft, and when the control valve is closed, θl = within the range of 230 to 290°, and when the control valve is open, set θh = within the range of 270 to 320°, and the control valve is opened and controlled at 3500 to 5000 rpm or higher during high load. When the valve is open, the closing timing of the second intake port is delayed from that of the first intake port; b) The opening period θf of the first intake port is set within the range of 230 to 290 degrees in rotation angle of the eccentric shaft. (c) The first and second intake passages of each cylinder are communicated with each other by a communication passage downstream of the throttle valve, and (d) Both cylinders are formed by the communication passage and the second intake passage downstream thereof. The passage length Lv between the second intake ports of the two cylinders is set within the range of 0.57 to 1.37 m. By setting the passage length Lf within the range of 1.31 to 1.83 m, the above control valve can be used at high engine speeds of 5,000 to 7,000 rpm when the control valve is open, and at 3,000 to 7,000 rpm when the control valve is closed.
When the engine is running at 4500rpm, the 2nd
The compression wave generated in the second intake passage when the intake port is opened is propagated through the communication passage to the second intake port just before the other cylinder is fully closed.
At high engine speed of 7000rpm, the first cylinder of one cylinder
The compression wave generated in the first intake passage when the intake port is closed is propagated to the first intake port of the other cylinder just before it is fully closed, thereby performing supercharging. The charging efficiency is increased by the supercharging effect due to the exhaust interference effect on the port (main port), and at high engine speeds, the double effect of the exhaust interference effect on the second intake port of both cylinders and the intake inertia effect on the first intake port is increased. The supercharging effect significantly increases charging efficiency.

Here, the standard rotational speed Nh (5000~
7000rpm) is generally set within this range, so the engine is in a high load, high rotation range and requires high output.
This is because it is an effective area for improving filling efficiency and output. Moreover, the reference rotation speed Nh mentioned above is the switching rotation speed Nc (3500~
5000), it is necessary to set Nh≧Nc+500rpm. This means that when the exhaust interference effect is obtained at the above reference rotation speed Nh, the effect (supercharging effect) extends to the rotation side 1000 rpm higher and lower than Nh around the reference rotation speed Nh, but the actual effect is Since it is within the range of 500 rpm, the exhaust interference effect at high engine speeds can only become effective when the engine speed is at least 500 rpm higher than the switching speed Nc.

In addition, the rotation speed Nl during engine rotation to obtain the exhaust interference effect is the reference rotation speed Nh (5000~
7000rpm) as well as the above switching speed Nc
(3500 to 5000 rpm), but
Similarly to the above, in order to make the exhaust interference effect effective during engine rotation, it is necessary to set Nl≦Nc−500 at 3000 to 4500 rpm.

In addition, the opening period θh of the second intake port when the control valve is open in setting item a above (when the auxiliary port is open) is 320°, which is the upper limit, when it is connected to the preceding working chamber via the side intake port. This is to prevent communication with the succeeding working chamber, and the opening period of the side seal is approximately 40° larger than the actual opening period of the rotor side. Since it is necessary to provide a gap of at least 100°, by suppressing the opening period to less than this, the minute gap (normally
This prevents communication between the intake working chamber and the subsequent exhaust working chamber through the (approx. It is something to do. On the other hand, the lower limit of 270° is the minimum period of the geometrical intake stroke from top dead center (TDC) to bottom dead center (BDC). It is necessary to set the period longer than this.

On the other hand, when the control valve is closed (auxiliary port closed), the opening period θl of the second intake port, that is, the main port, is set in the range of 230 to 290°, and θh, Nl , Nh to satisfy the following relationship: θl = 180° + θ ₀ + (θh − 180° − θ ₀ ) × (Nl/Nh).

The setting of this θl and the setting of the opening period θf of the first intake port in setting item b above are because the main port and the first intake port are mainly responsible for the low rotation range where the amount of intake air is small and the inertia is small. The timing should be set before about 50 degrees after bottom dead center to prevent the intake air from blowing back.
The opening timing cannot be set before approximately 30° after top dead center due to the corner seal falling into the intake port.
Further, since it is necessary to secure the necessary intake air by ensuring the opening period is at least 230 degrees, the angle is set at 230 to 290 degrees.

In addition, the opening period θh, θl, of each intake port of the present invention
θf is the actual opening/closing period of each intake port by the side surface of the rotor, and is not caused by the side seal. This is because the minute gap on the outside of the side seal has no substantial effect on the generation and propagation of effective pressure waves in the medium and high rotation ranges, which is the problem of the present invention.

In addition, the downstream position of the throttle valve in each communication path in setting item c above is set in order to avoid the presence of the throttle valve, which acts as a resistance to the propagation of pressure waves (compression waves), and to attenuate the pressure waves. This is to reduce the size of the signal and propagate it effectively.

Furthermore, the passage length Lv between the second intake ports of both cylinders in setting item d above was set to obtain an exhaust interference effect during high engine rotations of 5000 to 7000 rpm and medium engine rotation of 3000 to 4500 rpm. This is the value obtained from the formula: Lv=(θh(l)−180− _θ0 )×(60/360Nh(l))×a...(). That is, in the above equation, θh and θl are θh during the second intake port opening period.
= 270 to 320°, θl = 230 to 290°, 180° is the phase difference between both cylinders, and θ ₀ is the period from the opening of the second intake port until the compression wave is substantially generated at the time of opening. and the period from just before the second intake port is fully closed to when the second intake port is fully closed, during which the opening compression wave is propagated in order to effectively perform supercharging, and θ ₀ ≒20°,
Therefore, (θh(l)−180−θ ₀ ) represents the rotation angle of the eccentric shaft required from generation of the compression wave at opening in one cylinder to propagation to the second intake port of the other cylinder. Also, Nh and Nl are the engine speeds, Nh = 5000 to 7000 rpm, Nl = 3000 to
4500 rpm, and 60/360 Nh (l) represents the time (seconds) required to rotate 1 degree. Also, a is the propagation velocity (sound velocity) of the pressure wave, and at 20°C a=
It is 343m/s. Therefore, from these values, Lv
=0.57~1.37m.

In addition, the passage length Lf between the first intake ports of both cylinders in the above setting e is set to obtain an exhaust interference effect at high engine speeds of 5000 to 7000 rpm, and is similar to the above equation (). Lf=(180−θ ₁ )×(60/360Nh)×a…() This is the value obtained from the formula. That is, in the above equation, θ ₁ is the period from when the closing compression wave is substantially generated until the first intake port is fully closed, and the period during which the closing compression wave is propagated in order to effectively perform supercharging. This is the invalid period that is the sum of the period from just before the first intake port is fully closed to when it is fully closed, and θ ₁ ≒ 20°. Therefore, (180−θ ₁ ) is the period from when the compression wave occurs when closing one cylinder to the other. represents the rotation angle of the eccentric shaft required for propagation to the first intake port of the cylinder. The rest is the same as the above formula (), so
Lf=1.31~1.83m.

Note that in the above equations () and (), the influence of the flow of intake air on the propagation of pressure waves is ignored. This is because the flow velocity is smaller than the speed of sound and causes almost no change in the length of the intake passage.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

Figures 1 and 2 show an embodiment in which the present invention is applied to a side intake port type two-cylinder rotary piston engine equipped with two intake passages, one for low load and one for high load, and equipped with variable ports. . 1A and 1B are a first cylinder and a second cylinder, and each cylinder 1A and 1B has a rotor housing 2 having a two-section trochoidal inner circumferential surface 2a, and a low-load intake air cylinder located on both sides of the rotor housing 2, which will be described later. Passage 20a, 20b
and side housings 5, 5 each having a low-load intake port 3 as a first intake port and a high-load intake port 4 as a second intake port in which high-load intake passages 21a and 21b are opened, respectively. A substantially triangular rotor 7 is supported by a single eccentric shaft 8 and rotates planetarily inside the casing 6, and the rotors 7, 7 of each cylinder 1A, 1B rotate at a rotation angle of 180 degrees with the rotation angle of the eccentric shaft 8. With the rotation of each rotor 7, three working chambers 9, 9,
The cylinders 1A and 1B are divided into 9 sections, and the intake, compression, explosion, expansion, and exhaust strokes are sequentially performed in each cylinder 1A and 1B with a phase difference of 180 degrees. still,
10 is an exhaust port provided in the rotor housing 2 for each cylinder 1A, 1B, 11 and 12 are leading side and trailing side spark plugs, 13 is a side seal attached to the side of the rotor 7, and 14 is each of the rotor 7. An apex seal 15 is attached to the top of the rotor 7, and corner seals 15 are attached to both sides of the top of the rotor 7.

The high-load intake port 4 provided in one side housing 5 in each of the cylinders 1A and 1B consists of a main port 4a that is always open and has a fixed opening area, and an auxiliary port 4b that is opened and closed and has a variable opening area. The auxiliary port 4b is provided with a control valve 16 that is a rotary valve that opens and closes the auxiliary port 4b and variably controls its opening area. an actuator 17 that controls the operation of the control valve 16 according to the
is connected, and when the engine speed during high engine load exceeds the switching speed Nc set within the range of 3500 to 5000 rpm, the auxiliary port 4b is opened and the opening area of the high load intake port 4 is fully opened. I try to do it. In addition, each of the above cylinders 1A,
The low-load intake port 3 provided in the other side housing 5 in 1B is a fixed port that is always open and has a fixed opening area.

Furthermore, the low-load and high-load intake ports 3 and 4 are opened and closed by the side surface of the rotor 7, and the closing timing of the auxiliary port 4b of the high-load intake port 4 is longer than the closing timing of the main port 4a of the eccentric shaft. It is set to delay more than 20 degrees at a rotation angle of 8. In addition, the opening period of the high-load intake port 4 changes, and the opening period θh when the control valve 16 is open (when the auxiliary port 4b is open) is 270 to 320 degrees at the rotation angle of the eccentric shaft 8. is set within the range, and when the control valve 16 is closed (when the auxiliary port 4b is closed), the opening period θ ₁ is
It is set within the range of 230 to 290 degrees and to satisfy the above relational expression between θh, Nl, and Nh. Furthermore, the opening period θf of the low-load intake port 3 is fixed and set within the range of θf=230 to 290°. Further, the closing timing of the high-load intake port 4 when the control valve 16 is open is set to be delayed by 20 degrees or more later than the closing timing of the low-load intake port 3. Furthermore, the opening timing of the low-load intake port 3 is set to be later than the opening timing of the high-load intake port 4, and the blowback of residual exhaust gas in the working chamber 9 is concentrated on the high-load intake port 4 side. This causes a strong compression wave to be generated at the opening of the high-load intake port 4.

On the other hand, 18 is a main intake passage whose one end opens to the atmosphere via an air cleaner 18a and supplies intake air to both cylinders 1A and 1B.
8 is provided with an air flow meter 19 for detecting the amount of intake air. The main intake passage 18 is connected to the main low-load intake passage 2 as a first intake passage by a partition wall 18b downstream of the air flow meter 19.
0 and the main high-load intake passage 2 as the second intake passage.
1, and the main low-load intake passage 20 has a low-load intake passage that opens in response to an increase in engine load and fully opens when the load exceeds a predetermined load to control the amount of intake air when the engine is under low load. A throttle valve 22 is disposed, and the main high-load intake passage 21 is provided with a high-load throttle valve 23 that opens when the engine load exceeds a predetermined load and controls the amount of intake air during high engine loads. It is set up. Further, the main low-load intake passage 20 is branched downstream of the low-load throttle valve 22 into first and second low-load intake passages 20a and 20b having the same shape and dimensions, and then, each cylinder 1
The main high-load intake passage 21 communicates with the working chambers 9, 9 through the low-load intake ports 3, 3 of A and 1B, and the main high-load intake passage 21 is connected to the first and second intake passages of the same shape and size downstream of the high-load throttle valve 23. 2 High load intake passage 21a,
21b, and then communicates with the working chambers 9, 9 via the high-load intake ports 4, 4 (main ports 4a, 4a and auxiliary ports 4b, 4b) of each cylinder 1A, 1B. For cylinders 1A and 1B,
The low-load intake passages 20a, 20b and the high-load intake passages 21a, 21b are configured to open independently into the working chamber 9 downstream of the low-load throttle valve 22.

The minimum passage area As of each of the above-mentioned high-load intake passages 21a, 21b is
Larger than the minimum passage area Ap of b (As>Ap)
and each high-load intake passage 21a, 21
The passage length ls of b is for each low-load intake passage 20a, 2.
It is set shorter than the passage length lp of 0b (ls<lp), and reduces the attenuation of pressure waves (compression waves due to exhaust interference effect) propagation through the high-load intake passages 21a and 21b. I try to do it effectively. In addition, each of the above-mentioned low-load intake passages 20a, 20
Electromagnetic valve type fuel injection nozzles 24, 24 whose fuel injection amount is controlled according to the output (intake air amount) of the air flow meter 19 are respectively disposed at b.

The branching portion of the main high-load intake passage 21 is located downstream of the high-load throttle valve 23, and includes a first high-load intake passage 21a and a second high-load intake passage 21.
It is constituted by an enlarged chamber 26 having a communication passage 25 communicating with b. The passage area Acs of the communication passage 25 is set to the first,
It is set to be equal to or larger than the minimum passage area As of the second high-load intake passages 21a and 21b (Acs≧As). Further, the branch portion of the main low-load intake passage 20 is similarly located downstream of the low-load throttle valve 22, and communicates the first low-load intake passage 20a and the second low-load intake passage 20b. The passage area Acp of the communication passage 27 is similar to that between the first and second chambers 28 so as to effectively transmit pressure waves (compression waves due to the intake inertia effect). It is set to be equal to or larger than the minimum passage area Acp of the low-load intake passages 20a and 20b (Acp≧Ap). Each of the enlarged chambers 26 and 28 functions as a surge tank during transient operation such as acceleration or deceleration of the engine, and ensures good fuel response.

Furthermore, the passage length Lv between the high-load intake ports 4 and 4 of the two cylinders 1A and 1B is the passage length lcs of the communication passage 25 and the first and second high-load intake passages downstream of the communication passage 25. Each passage length ls of 21a and 21b,
ls (Lv = lcs + 2ls), and from the above formula (), Lv = 0.57 to 1.37 (m).

Furthermore, the passage length Lf between the low-load intake ports 3 and 3 of the two cylinders 1A and 1B is the passage length lcp of the communication passage 27 and the first and second low-load intake passages downstream of the communication passage 27. Each path length lp, lp of 20a, 20b
(Lf=lcp+2lp), and from the above equation (), Lf is set to 1.31 to 1.83 (m).

In FIG. 2, 29 is an exhaust passage connected to the exhaust port 10, and 30 is an enlarged manifold for exhaust purification that assists a catalyst device (not shown) interposed in the middle of the exhaust passage 29. .

Next, the operation of the above embodiment will be explained with reference to FIG. 3.
5000~7000rpm on the high rotation side of 500rpm or more
When the engine is under high load and at high speed Nh, the first and second high load intake passages 21a and 21b are opened by the opening operation of the high load throttle valve 23, and each cylinder 1
High load intake ports 4 and 4 of A and 1B are control valve 1
6 is fully opened and the high load intake ports 4, 4 (main ports 4a, 4a and auxiliary port 4
b, 4b), and the low-load intake ports 3, 3 independently supply intake air. At this time, when the high-load intake port 4 of one cylinder, for example, the second cylinder 1B, is opened, the intake air is compressed by the pressure of the residual exhaust gas and is opened to the high-load intake port 4 in the second high-load intake passage 21b. A time compression wave is generated. This compression wave at the time of opening is generated in both cylinders 1A and 1B.
By setting the passage length Lv between the high-load intake ports 4 and 4 to 0.57 to 1.37 m using the above formula () based on the engine high rotation of 5000 to 7000 rpm, the second high-load intake passage 21b → communication passage 25 → first high-load intake passage 21a,
It propagates to the high-load intake port 4 of the first cylinder 1A, which has a phase difference of 180 degrees, just before it is fully closed.

At the same time, in the previous intake stroke, the second cylinder
When the low-load intake port 3 of B is closed, the intake air is compressed by the inertia of the intake air and flows into the second low-load intake passage 2.
A compression wave occurs in the low-load intake port 3 portion in 0b, and this compression wave occurs in both cylinders 1A,
Passage length between low load intake ports 3 and 3 of 1B
By setting Lf to 1.31 to 1.83 m using the above formula () based on the high engine speed of 5000 to 7000 rpm, the second low load intake passage 20b → communication passage 27 → first low load intake passage 20a Then, it propagates to the low-load intake port 3 of the first cylinder 1A just before it is fully closed.

As a result, the closing and opening compression waves propagated to the low-load and high-load intake ports 3 and 4 cause the low-load and high-load intake ports 3 and 4 to The blowback of the intake air is suppressed and the intake air is pushed into the working chamber 9,
In other words, supercharging will occur. Next, the first
Similarly, each compression wave generated when the high-load intake port 4 of the cylinder 1A is opened and the low-load intake port 3 is closed is the same as that of the high-load intake port 4 and the low-load intake port 3 immediately before the second cylinder 1B is fully closed. Supercharging is performed by propagating to each. Thereafter, in the same way, cylinder 1
A strong supercharging effect occurs due to the mutual effect of the exhaust interference effect in the high-load intake system between A and 1B and the intake inertia effect in the low-load intake system, resulting in a high engine load with high output requirements. The charging efficiency during rotation is significantly increased, and the engine output can be effectively improved to a large extent.

On the other hand, the switching rotation speed Nc of the control valve 16
For Nl during high engine load and medium rotation of 3000 to 4500 rpm on the low rotation side of 500 rpm or more, each cylinder 1A, 1B
In the high-load intake port 4, the auxiliary port 4b is closed by the closing operation of the control valve 16, and intake air is supplied from the main port 4a. At that time, as described above, when the high-load intake port 4 of each cylinder 1A, 1B is opened, a compression wave is generated when the high-load intake port 4 is opened, and this compression wave when the high-load intake port 4 (main port 4a) is opened is generated. The opening period θ ₁ is 230 to 290°, and θh, Nl,
Since the relationship between the two cylinders 1A and 1B is set to satisfy the above relational expression, supercharging is similarly carried out to the high-load intake port 4 of the other cylinders 1A and 1B just before they are fully closed. Therefore, similarly, due to the supercharging effect due to the exhaust interference effect in the high-load intake system between the cylinders 1A and 1B, the charging efficiency during the middle rotation of the engine can be increased, and the output can be improved.

Therefore, in this way, between cylinders 1A and 1B, when the engine is under high load and high rotation speed (5000~
7000rpm) and high load medium rotation (3000rpm~
4500rpm), the exhaust interference effect on the high-load intake port 4 just before full closure in the high-load intake system, and the effect of exhaust interference on the high-load intake port 4 at high-load and high-speed engine rotations (5000~
Due to the intake inertia effect on the low-load intake port 3 just before fully closing the low-load intake system at 7000 rpm), the charging efficiency increases at high and medium engine speeds, as shown in Figure 4. output can be improved. In particular, when the engine rotates at high speeds, the output can be effectively improved due to the exhaust interference effect and intake inertia effect in the two systems. Furthermore, the fourth
In the figure, the high-load intake system operates at 6000 rpm, compared to the conventional case (indicated by broken lines) in which the low-load and high-load intake passages 20a, 20b, 21a, and 21b of each cylinder 1A and 1B are independent. According to the present invention, the exhaust interference effect (indicated by the dashed-dotted line) is obtained as a reference, and the exhaust interference effect (indicated by the dashed-dotted line) is obtained at 4000 rpm, and the intake inertia effect is obtained at 6000 rpm in the low-load intake system. 2 shows the output torque characteristics of the engine in the case (indicated by the solid line).

In that case, the high-load intake passages 21a and 21b, which are propagation paths for obtaining the exhaust interference effect,
has a larger passage area than the low-load intake passages 20a and 20b, and has a shorter passage length, so
The resistance to the propagation of pressure waves (compression waves) is small, and the supercharging effect due to the exhaust interference effect in the high-load intake system can be effectively exerted.

Further, each of the communication passages 25 and 27 is located downstream of the high-load and low-load throttle valves 23 and 22, and the passage areas of each of the communication passages 25 and 27 are Acs and Acp.
The high load and low load intake passages 21a, 21
b and the minimum passage area of 20a, 20b As, Ap
Since the above-mentioned throttle valves 23, 2 are set to be equal to or higher than
2 and the communication passages 25, 27 themselves, the pressure waves are not attenuated, and the above-mentioned exhaust interference effect and intake inertia effect can be effectively exhibited.

In addition, the supercharging effect due to the above exhaust interference effect and intake inertia effect includes the opening periods θf, θh, θl of the low-load and high-load intake ports 3 and 4, the opening operation range of the control valve 16, and the high-load intake passage. 21a, 21b and the low load intake passages 20a, 20b, the positions of the communication passages 25, 27, the passage length Lv between the high load intake ports 4, 4 of both cylinders 1A, 1B, and the low load This is obtained by setting the passage length Lf between the intake ports 3 and 3 as described above, and since a supercharger etc. is not required, only a slight design change to the existing intake system is required, and the structure is extremely simple. Therefore, it can be implemented easily and inexpensively.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but also includes various other modifications. For example, setting the intake/exhaust overlap period to a range of 0 to 20 degrees in rotation angle of the eccentric shaft improves filling efficiency and
This is preferable in order to reduce the amount of dilution gas brought in and to prevent misfires, especially when the engine is under low load.

Furthermore, in the above embodiment, a case has been described in which the high load intake port 4 is a variable port and the low load intake port 3 is a fixed port structure, but the low load intake port 3 is a variable port and the high load intake port is a fixed port structure. It is also applicable when 4 has a fixed port structure.
In that case, the low-load intake system will have an exhaust interference effect at high engine speeds of 5000 to 7000 rpm and the medium engine speed of 3000 to 4500 rpm, and the high-load intake system will produce intake inertia at high engine speeds of 5000 to 7000 rpm. Just set it up to get the desired effect. However, as mentioned above, the high-load intake passage 2
1a, 21b are low load intake passages 20a, 20b
The structure of the above embodiment is advantageous because the minimum passage area is larger and the passage length is shorter, so that the exhaust interference effect with a strong supercharging effect can be effectively exerted.
In addition, it has two independent intake passages,
This is applicable when the intake port of one of the intake passages is a variable port.

Furthermore, in the above embodiment, the low load throttle valve 22
In the above description, the low-load throttle valve 22 is installed in the main low-load intake passage 20 upstream of the branch between the main low-load intake passage 20 and the main high-load intake passage 21. A type provided in the intake passage 18 can also be adopted.

As explained above, according to the present invention, in a side intake port type two-cylinder rotary piston engine equipped with a variable port, when the engine rotates at a high speed of 5000 to 7000 rpm, the air flow between the cylinders in the intake system on the variable port side is A supercharging effect is obtained by the exhaust interference effect and the intake inertia effect between cylinders in the intake system on the fixed port side, and exhaust interference between cylinders in the intake system on the variable port side is achieved when the engine rotates at medium speeds of 3000 to 4500 rpm. Since the supercharging effect is obtained by the effect, even a very simple configuration with a slight design change of the existing intake system can be used without the need for a supercharger etc.
It is possible to effectively improve the output by increasing the charging efficiency at high and medium rotations of the engine, and in particular, it is possible to greatly improve the output when the engine is at high rotations, which require high output. Therefore, it can greatly contribute to the easy implementation of measures to improve the output of rotary piston engines and cost reduction.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is an explanatory diagram of the overall configuration, FIG. 2 is an overall schematic diagram, FIG. 3 is an explanatory diagram showing the intake stroke of the first and second cylinders, and FIG. 4 is an illustration of the main structure. 3 is a graph showing output torque characteristics according to the invention. 1A...1st cylinder, 1B...2nd cylinder, 2...
Rotor housing, 2a...Two-section trochoidal inner peripheral surface, 3...Intake port for low load, 4...Intake port for high load, 4a...Main port, 4b...Auxiliary port, 5...Side housing, 6...Casing, 7...Rotor, 8...Eccentric shaft, 9...Working chamber, 16...Control valve, 18...
...Main intake passage, 20...Main low-load intake passage, 2
0a...first low-load intake passage, 20b...second
Low load intake passage, 21... Main high load intake passage, 21a... First high load intake passage, 21b...
...Second high load intake passage, 22...Low load throttle valve, 23...High load throttle valve, 25...Communication passage,
27...Communication path.

Claims (1)

[Scope of Claims] 1. A substantially triangular rotor disposed within each casing formed of a rotor housing having a two-bar trochoidal inner peripheral surface and side housings located on both sides of the rotor housing has an eccentric rotor. It is supported by a shaft and rotates planetarily with a phase difference of 180 degrees at the rotation angle of the shaft, and a first
The intake passage and the second intake passage are each independently provided in each side housing, and the opening period is fixed.
In a two-cylinder rotary piston engine that opens into the working chamber through a second intake port whose opening period changes depending on the opening and closing of the intake port and the control valve, a. It consists of an auxiliary port that closes later than the main port and is opened and closed by the control valve, and the opening period is 230~230° when the control valve is closed at the rotation angle of the eccentric shaft.
When the control valve is open within the range of 290°
270 to 320 degrees, and the above control valve is opened at 3500 to 5000 rpm or more during high engine load, and the closing timing of the second intake port when the control valve is open is set to the first intake port. (b) Setting the opening period of the first intake port within the range of 230 to 290 degrees in rotation angle of the eccentric shaft; (c) Setting the first and second intake passages of each cylinder to the downstream side of the throttle valve. d) The passage length between the second intake ports of both cylinders formed by the communication passage and the second intake passage downstream thereof is set within the range of 0.57 to 1.37 m. (e) By setting the passage length between the first intake ports of both cylinders formed by the communication passage and the first intake passage downstream thereof within the range of 1.31 to 1.83 m, the control valve At high engine speeds of 5000 to 7000 rpm with the control valve closed and 3000 to 7000 rpm with the control valve closed.
When the engine is running at 4500rpm, the 2nd
The compression wave generated in the second intake passage when the intake port is opened is propagated through the communication passage to the second intake port just before the other cylinder is fully closed.
At high engine speed of 7000rpm, the first cylinder of one cylinder
A rotary piston characterized in that a compression wave generated in the first intake passage when the intake port is closed is propagated through the communication passage to the first intake port of the other cylinder just before it is fully closed, thereby performing supercharging. Engine intake system.