JPH0337011B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for a rotary piston engine, and more particularly to a side intake port type two-cylinder rotary piston engine having two independent intake passages, one for low load and one for high load. The present invention relates to an engine in which a supercharging effect is obtained from a medium speed range to a high speed range of an engine by utilizing intake pressure waves generated in an intake passage.

Generally, such a two-system side intake port type two-cylinder rotary piston engine is arranged in a casing formed by a rotor housing having a two-section trochoidal inner peripheral surface and side housings located on both sides of the rotor housing. A substantially triangular rotor is supported on an eccentric shaft and rotates planetarily with a phase difference of 180 degrees at the rotation angle of the shaft, and a low-load intake passage is provided with a low-load throttle valve. A low-load intake passage equipped with a high-load throttle valve opens into the working chamber through low-load and high-load intake ports provided independently in each of the side housings downstream of the low-load throttle valve. The intake, compression, explosion, expansion, and exhaust strokes are sequentially performed in each cylinder as the rotor rotates while maintaining the above-mentioned 180° phase difference between the two cylinders. When the engine is under low load, only the low-load throttle valve is opened to supply intake air only from the low-load intake passage, which has a narrow passage area, thereby increasing the intake flow rate and improving combustion stability. When the engine is under high load, the so-called dual induction system is designed to open the high-load throttle valve and supply intake air from the high-load intake passage to increase charging efficiency and improve output. It is called. In addition to the type in which the low-load throttle valve is provided in the low-load intake passage, there is also a type in which the low-load throttle valve is provided upstream of the branch between the low-load intake passage and the high-load intake passage.

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 inventors found that (i) when the intake port is opened, the intake air is compressed due to the inertia of the intake air, and a compression wave is generated at the intake port portion in the intake passage; (ii) It was discovered that when the intake port opens, the intake air is compressed by the pressure of the residual exhaust gas in the working chamber, and a compression wave is generated in the intake port portion of the intake passage. From this, the above for one cylinder
(i) If the compression wave at the time of closing is applied to the intake port of the other cylinder, especially just before fully closing, where intake air blowback occurs, a supercharging effect can be effectively obtained (hereinafter referred to as intake inertia effect). , and that a supercharging effect can be effectively obtained by applying the compression wave at the time of opening of (ii) above in one cylinder to the intake port of the other cylinder just before it is fully closed (hereinafter referred to as exhaust interference effect). ).

In the two-system side intake port type two-cylinder rotary piston engine as described above, in order to obtain the above-mentioned intake inertia effect and exhaust interference effect, the high-load intake passage and the low-load intake passage are independent of each other. Since there are two systems of intake passages, each of the above-mentioned effects can be effectively obtained in each intake system.

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, an object of the present invention is to provide a two-system side intake port type two-cylinder rotary piston engine as described above, with each opening period of the high-load and low-load intake ports, and the high-load and low-load intake ports. By appropriately setting the position of the communication passage that connects the intake passages and the length of the passage between the high-load intake ports and the low-load intake ports of both cylinders, the engine speed of 5000 to 7000 rpm, which requires high output, can be improved. During rotation, a supercharging effect is obtained due to the intake inertia effect in one intake system, and a supercharging effect is obtained due to the exhaust interference effect in the other intake system at lower rotation speeds, and the supercharger etc. The aim is to effectively improve the output by increasing the charging efficiency from the mid-speed range to the high-speed range of the engine through a simple configuration by making slight design changes to the existing intake system.

In order to achieve this objective, the configuration of the present invention is as follows:
Approximately triangular rotors are disposed within a casing formed by a rotor housing having a nodular trochoidal inner circumferential surface and side housings located on both sides of the rotor housing, and are supported by an eccentric shaft to adjust the rotation angle of the shaft. The engine rotates planetarily with a phase difference of 180 degrees, and the low-load intake passage and the high-load intake passage are independently provided by low-load and high-load intake ports provided in each side housing. In a two-cylinder rotary piston engine that opens into the working chamber, a) the opening period θs of the high-load intake port should be set within the range of 270 to 320° in terms of the rotation angle of the eccentric shaft; b) the opening of the low-load intake port Set the period θp within the range of 230 to 290 degrees in rotation angle of the eccentric shaft, c. Connect the low-load intake passages and the high-load intake passages of each cylinder through a communication passage downstream of the throttle valve. (d) When the engine speed is high, with the passage length Lp (s) between the intake ports of both cylinders formed by one of the communicating passages and the intake passage downstream thereof being set between 5000 and 7000 rpm, one side setting so that a compression wave generated in the intake passage when the intake port of the cylinder is closed is propagated through the communication passage to the intake port of the other cylinder just before being fully closed, e. The passage length Ls (p) between the intake ports of both cylinders formed by the downstream intake passage is set to 3500 to 5000 rpm, which is at least 1000 rpm lower than the rotation speed set between 5000 and 7000 rpm. When the engine is running at medium speed, the compression wave generated in the intake passage when the intake port of one cylinder is opened is set so as to propagate through the communication passage to the intake port of the other cylinder just before it is fully closed. Under these conditions, supercharging is performed by compression waves that propagate to the low-load and high-load intake ports of each cylinder just before they are fully closed, thereby reducing the intake inertia effect at high engine speeds in one intake system. The exhaust interference effect in the other intake system during engine mid-speed rotation effectively increases the charging efficiency from the mid-engine speed range to the high-speed engine speed range.

Here, 5000 ~ 5000 at high engine speed to obtain the intake inertia effect with one of the intake systems mentioned above.
The limitation of the standard rotational speed Nh to 7000 rpm is because the maximum output and maximum speed are generally set within this range, so the engine is in the high load, high rotation range and requires high output, and is therefore useful for improving charging efficiency and output. It depends on being a valid area. In addition, when the engine is running at mid-speed, the exhaust interference effect is obtained with the other intake system.
The setting of the rotation speed Nl from 3500 to 5000 rpm is because the maximum torque is generally set in this rotation range, the exhaust interference effect is difficult to obtain in the low rotation range, and the intake inertia effect is obtained at the above reference rotation speed Nh. In this case, the effect (supercharging effect) is Nn around the reference rotation speed Nh.
Since the speed ranges from 1000rpm to high and low rotational speeds, obtaining the exhaust interference effect at least 1000rp or more lower than the reference rotational speed Nh (Nl≦Nh−1000rpm) can improve the overall output. .

In addition, the upper limit of the opening period θs of the high-load intake port in setting item a above is 320° to prevent communication between the preceding working chamber and the following working chamber via the side intake port. , the opening period due to the side seal is approximately 40° larger than the actual opening period due to the rotor side surface, and it is necessary to provide an interval of 40° or more in order to avoid this side seal opening period lapping, so the opening period less than this is required. By suppressing the opening period, communication between the intake working chamber and the subsequent exhaust working chamber is prevented through the minute gap (usually about 200μ) between the inner sliding surface of the side housing on the outside of the side seal and the rotor side. This prevents exhaust gas from entering the intake working chamber during low engine speeds and low loads, such as when idling, thereby ensuring stable combustion. On the other hand, the lower limit of 270° is
This is the minimum period of the geometric intake stroke from intake top dead center (TDC) to bottom dead center (BDC), and in order to perform effective intake, it is necessary to set at least the opening period longer than this. .

When setting the opening/closing timing of this high-load intake port, the opening timing must be delayed from the top dead center, and the closing timing must be delayed from the bottom dead center. This is because the effect of the geometrical intake stroke is delayed due to the inertia of the intake air amount in the high rotation range, which is mainly handled by the high-load intake ports, and in addition, the opening timing of the side intake ports is increased. This is because the tip of the rotating side of the side seal falls into the port as it approaches the dead center, so it must be set at about 30 degrees or more after the top dead center.

On the other hand, low-load intake ports are mainly responsible for the low-speed range where the amount of intake air is small and the inertia is small. period
It is necessary to secure the necessary intake air by setting the angle to 230° or more. Therefore, the opening period θp of the low-load intake port is set to 230 to 290 degrees as in setting item b.

Incidentally, the opening period of the high-load and low-load intake ports of the present invention is the substantial opening/closing period of the intake ports by the side surface of the rotor, and is not due to 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 passage in setting item c above should be determined because the existence of the throttle valve that controls the air flow rate in the high-load and low-load intake passages acts as a resistance to the propagation of pressure waves. This is to avoid this, and to reduce the attenuation of the pressure waves so that they can propagate effectively.

Furthermore, the passage length Lp (s) between the intake ports of both cylinders in one intake system in the setting item d above is the same as that when the engine speed is the reference rotation speed Nh set within the range of 5000 to 7000 rpm. It is set to effectively obtain an inertial effect, and is a value obtained from the formula Lp(s)=(180−θ ₀ )×60/360Nh)×a (). That is, in the above equation (), 180° is the phase difference between both cylinders,
In addition, θ ₀ is the period from when the compression wave at the time of closing is substantially generated at the intake port until it is fully closed, and from the time just before the intake port is fully closed when the compression wave at the time of closing is propagated to effectively perform supercharging. The invalid period is the sum of the period when the cylinder is fully closed, and θ ₀ ≒ 20°, so (180 − θ ₀ ) is the propagation from the compression wave generated at the time of closing in one cylinder to the intake port of the other cylinder. It represents the rotation angle of the eccentric shaft required to reach Also, Nh=
5000 to 7000 rpm, and 60/360Nh 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.

Furthermore, the passage length ls(p) between the intake ports of both cylinders of the other intake system in the above setting e is:
The engine speed is 1000rpm or more lower than the standard rotational speed Nh within the range of 5000 to 7000rpm, from 3500 to 3500.
It is set to effectively obtain the exhaust interference effect when Nl is within the range of 5000 rpm, Ls (p) = (θs (p) - 180 - θ ₁ ) × (60/360Nl) × a... ...This is the value obtained from the formula (). That is, in the above equation (), θs and θp are the intake port opening periods for high load and low load, θs = 270 to 320°, θp
= 230 to 290°, 180° is the phase difference between both cylinders, and θ ₁ is the period from the opening of the intake port until the compression wave is substantially generated at the time of opening, and for effective supercharging. The ineffective period is the sum of the period from just before the intake port is fully closed to when the opening compression wave is propagated, and θ ₀ ≒ 20°, so (θs(p)
−180−θ ₁ ) represents the rotation angle of the eccentric shaft required from generation of the compression wave at opening in one cylinder to propagation to each intake port of the other cylinder. Also, 60/360Nl represents the time (seconds) required to rotate 1°. Also, a=343 m/s (at 20°C).

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.

In Figures 1 and 2, 1A and 1B
are the first and second cylinders in a two-system side intake port type two-cylinder rotary piston engine, one for low load and one for high load.
A and 1B each have a two-section trochoidal inner peripheral surface 2a.
A rotor housing 2 having a rotor housing 2, and a low-load intake port 3 and a high-load intake port 4 located on both sides of the rotor housing 2, in which low-load intake passages 20a, 20b and high-load intake passages 21a, 21b, which will be described later, open respectively. A substantially triangular rotor 7 is supported by a single eccentric shaft 8 and rotates planetarily within a casing 6 formed by side housings 5, 5 provided with , 7 is the rotation angle of the eccentric shaft 8.
With a phase difference of 180 degrees, the inside of the casing 6 is divided into three working chambers 9, 9, 9 as each rotor 7 rotates, and the above-mentioned
The intake, compression, explosion, expansion, and exhaust strokes are performed sequentially with a phase difference of 180°. Furthermore, 1
0 is an exhaust port provided in the rotor housing 2 in each cylinder 1A, 1B, 11 and 12 are leading side and trailing side spark plugs,
13 is a side seal attached to the side surface of the rotor 7; 14 is an apex seal attached to each top of the rotor 7; and 15 is a corner seal attached to both sides of each top of the rotor 7.

Low-load and high-load intake ports 3 and 4 provided opposite to the above-mentioned both side housings 5 and 5
is opened and closed by the side surface of the rotor 7, and the opening period θs of the high-load intake port 4 is set in the range of 270 to 320 degrees based on the rotation angle of the eccentric shaft 8, and the opening period of the low-load intake port 3 θp is 230~
It is set to a range of 290°. Furthermore, the opening timing of the high-load intake port 4 is set earlier than the opening timing of the low-load intake port 3, so that a strong compression wave is generated when opening from the high-load intake port 4. I have to. Further, the opening timing of the high-load intake port 4 is set to be the same as or later than the opening timing of the low-load intake port 3.

On the other hand, 16 is a main intake passage whose one end opens to the atmosphere via an air cleaner 17 to supply intake air to both cylinders 1A and 1B.
is equipped with an air flow meter 1 that detects the amount of intake air.
8 are arranged. The main intake passage 16 is connected to a main low-load intake passage 20 and a main high-load intake passage 2 by a partition wall 19 downstream of the air flow meter 18.
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 of each cylinder 1A, 1B, and therefore, for each cylinder 1A, 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), so that the compression wave propagation due to the exhaust interference effect by the high-load intake passages 21a and 21b is effectively carried out by reducing its attenuation. ing. In addition, the output (intake air amount) of the air flow meter 18 is provided in each of the low-load intake passages 20a and 20b.
Electromagnetic valve type fuel injection nozzles 24, 24 are provided whose fuel injection amount is controlled according to the fuel injection amount.

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 so as to reduce attenuation of pressure waves (compression waves due to exhaust interference effect) and effectively transmit them.
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. It is constituted by an expansion chamber 28 having a communication passage 27. The passage area Acp of the communication passage 27 is set such that the first and second low-load intake passages 20a,
It is set to be equal to or larger than the minimum passage area Ap of 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.

Further, the passage length Lp between the low and low load intake ports 3 and 3 of the above-mentioned cylinders 1A and 1B is the passage length lcp of the communication passage 27 and the first and second low load intake ports downstream of the communication passage 27. Each passage length lp of passages 20a and 20b,
It is the sum of lp and (Lp = lcp + 2lp),
From the above formula (), Lp is set to 1.31 to 1.83 (m) so as to obtain the intake inertia effect based on the engine high rotation at a reference rotation speed Nh within the range of 5000 to 7000 rpm.

In addition, the passage length Ls 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 ports downstream of the communication passage 25. Each passage length ls of passages 21a and 21b,
ls (Ls = lcs + 2ls), which is higher than the standard rotation speed Nh of 5000 to 7000 rpm above.
Based on the above formula (), Ls is set to 0.80 to 1.96 (m) in order to obtain the exhaust interference effect based on the engine rotation speed Nl in the range of 3500 to 5000 rpm on the low rotation side of 1000 rpm or more. .

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. When the engine is under high load, the high load throttle valve 2
3 opens the first and second high-load intake passages 2.
1a and 21b are opened, and intake air is supplied from the high-load intake ports 4, 4 of each cylinder 1A, 1B independently of the low-load intake ports 3, 3. When the engine rotates at a high speed of 5000 to 7000 rpm, which requires high output, when one cylinder, for example, the low-load intake port 3 of the second cylinder 1B, is closed, the intake air is compressed by the inertia of the intake air, and the second low-negative low-use intake passage 20b is compressed.
Compression waves occur in the low-load intake port 3 portion when the valve is closed. This compression wave at the time of closing occurs in both cylinders 1A and 1.
Passage length Lp between low load intake ports 3 and 3 of B
By setting Lp to 1.31 to 1.83 m using the above formula () based on the above engine high rotation of 5000 to 7000 rpm, the second low-load intake passage 20b
→The communication passage 27→The first low-load intake passage 20a is propagated to the low-load intake port 3 of the first cylinder 1A, which has a phase difference of 180 degrees and is just before fully closed. the result,
Due to this compression wave during closing, intake air is forced into the working chamber 9 from the low-load intake port 3 immediately before the first cylinder 1A is fully closed, and supercharging is performed. Similarly, in the second cylinder 1B, the compression wave at the time of closing from the first cylinder 1A propagates to the high-load intake port 3 immediately before fully closing, so that a supercharging effect is obtained.

On the other hand, when the engine rotates in the middle range of 3500 to 5000 rpm, which is 1000 rpm or more lower than the reference rotation speed Nh of 5000 to 7000 rpm, a compression wave is generated when the high load intake port 4 of each cylinder 1A and 1B is opened.
This compression wave at the time of opening causes the passage length Ls between the high-load intake ports 4 and 4 of both cylinders 1A and 1B to be
By setting Ls=0.80 to 1.96 m according to the formula, supercharging is carried out via the communication passage 25 to the high-load intake port 4 of the other cylinders 1A and 1B just before they are fully closed.

Therefore, between cylinders 1A and 1B, there is a supercharging effect due to the intake inertia effect in the low-load intake system during high engine speeds, and an exhaust interference effect in the high-load intake system during medium engine speeds. Due to the supercharging effect, as shown in FIG. 4, the output can be improved by increasing the charging efficiency from the middle speed range to the high speed range of the engine. In addition, in FIG. 4, the low-load and high-load intake passages 20a, 20b, 21a, 21b of each cylinder 1A, 1B are shown.
In contrast to the conventional example in which each is independent (shown by the broken line), the intake inertia effect is obtained in the low-load intake system based on 6000 rpm, and the exhaust interference effect is obtained in the high-load intake system based on 4000 rpm. 5 shows the output torque characteristics of the engine in the case of the present invention example (indicated by a solid line).

In that case, especially the high load intake passage 21
a, 21b are low load intake passages 20a, 20b
Since the passage area is larger and the passage length is shorter, there is less resistance to the propagation of pressure waves (compression waves), and the intake inertia effect in the above-mentioned high-load intake system can be effectively exerted. .

Further, each of the communication passages 25 and 27 is connected to each throttle valve 2.
2, 23 downstream, and each communication path 25,
The passage areas Acs and Acp of No. 27 are equal to or greater than the minimum passage areas As and Ap of the high-load and low-load intake passages 21a, 21b, 20a, and 20b, and each of the above-mentioned throttle valves 22 and 23 and each communication passage 25,2
The pressure waves are not attenuated by 7 itself, and the intake inertia effect and exhaust interference effect in each intake system can be effectively exhibited.

Furthermore, in the above embodiment, the intake inertia effect was set to be obtained in the low-load intake system during high engine speeds, and the exhaust interference effect was obtained in the high-load intake system during medium engine speeds. The passage length ls of the high-load intake passages 21a and 21b can be made as large as possible compared to the case where the intake inertia effect is obtained in the high-load intake system during engine rotation, and the exhaust interference effect is obtained in the low-load intake system during mid-engine rotation. It can be shortened to suit the dual induction characteristics (improvement of filling efficiency) of the high-load intake passages 21a and 21b.

Furthermore, by opening the high-load intake port 4 earlier than the low-load intake port 3, the blowback of exhaust gas is concentrated on the high-load intake port 4 side. Since a strong compression wave can be generated when the intake port 4 opens, the exhaust interference effect in the high-load intake system can be made even stronger.

In addition, the supercharging effect due to the intake inertia effect and the exhaust interference effect is due to the opening period of the low-load and high-load intake ports 3 and 4, and the high-load intake passage 21
a, 21b and low load intake passage 20a,
The positions of the communication passages 25 and 27 that communicate with each other and the passage lengths Ls and Lp between the high-load intake ports 4 and 4 and between the low-load intake ports 3 and 3 of both cylinders 1A and 1B are determined as described above. Since it does not require a supercharger or the like, it requires only a slight design change to the existing intake system, and the structure is extremely simple, so it can be implemented easily and at low cost. .

It should be noted that the present invention is not limited to the above-mentioned embodiments, but also includes various other modifications. For example, unlike the above embodiment, it is of course possible to obtain the intake inertia effect in the low-load intake system when the engine is running at high speeds, and to obtain the exhaust interference effect in the low-load intake system when the engine is running at medium speeds.

In addition, setting the intake/exhaust overlap period to a range of 0 to 20 degrees based on the rotation angle of the eccentric shaft improves charging efficiency and reduces the amount of dilution gas brought in, especially when the engine is under low load. This is preferable in order to prevent misfires.

Further, in the above embodiment, the low load throttle valve 22 is provided in the main low load intake passage 20, but the low load throttle valve 22 is installed in the main low load intake passage 20 and in the main low load intake passage 20. A type provided in the main intake passage 16 upstream of the branching portion with the load intake passage 21 may also be adopted.

As explained above, according to the present invention, in a side intake port type two-cylinder rotary piston engine equipped with two independent intake passages for low load and high load, the engine speed is high at 5000 to 7000 rpm. At the same time, a supercharging effect is obtained due to the intake inertia effect between the cylinders in one intake system, and when the engine is running at mid engine speed of 3500 rpm to 5000 rpm, which is 1000 pm or more lower than the reference rotation speed of 5000 to 7000 rpm, the other intake system Since the supercharging effect is obtained by the exhaust interference effect between cylinders in the system,
Even with a simple configuration that requires only slight design changes to the existing intake system, without the need for a supercharger, it is possible to effectively improve output by increasing charging efficiency from the mid- to high-speed range of the engine. 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 drawings]

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, 5...Side housing, 6...
Casing, 7...Rotor, 8...Eccentric shaft, 9...Working chamber, 16...Main intake passage, 20...Main low load intake passage, 20a...First low load intake passage, 20b... Second low load intake passage, 21... Main high load intake passage, 21a...
...First intake passage for high load, 21b... Second intake passage for high load, 22... Throttle valve for low load, 23...
High-load throttle valve, 25... communication passage, 27... communication passage.

Claims (1)

[Scope of Claims] 1. Approximately triangular rotors each disposed within a casing formed of a rotor housing having a two-bar trochoidal inner circumferential surface and side housings located on both sides of the rotor housing have eccentric shafts. The shaft is supported by the shaft and rotates planetarily with a phase difference of 180 degrees at the rotation angle of the shaft, and a low-load intake passage and a high-load intake passage are independently provided in each side housing. In a two-cylinder rotary piston engine in which a high-load intake port opens into the working chamber, a) the opening period of the high-load intake port is set in the range of 270 to 320 degrees in rotation angle of the eccentric shaft; b. Set the opening period of the load intake port in the range of 230 to 290 degrees in rotation angle of the eccentric shaft, c. Connect the low-load intake passages and high-load intake passages of each cylinder downstream of the throttle valve. communicating through a passage; d; when the engine is running at high speed, when the passage length between the intake ports of both cylinders formed by one of the communication passages and the intake passage downstream thereof is set between 5000 and 7000 rpm; setting so that the compression wave generated in the intake passage when the intake port of the cylinder is closed is propagated through the communication passage to the intake port of the other cylinder just before it is fully closed, e. The length of the passage between the intake ports of both cylinders formed by the intake passage of
When the engine rotates at a medium speed of 5000 rpm, the compression wave generated in the intake passage when the intake port of one cylinder is opened is set so as to be propagated through the communication passage to the intake port of the other cylinder just before it is fully closed. Therefore, an intake system for a rotary piston engine is characterized in that supercharging is performed by compression waves propagated to the low-load and high-load intake ports of each cylinder immediately before they are fully closed.