JPH0337010B2 - - 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 for low load and high load. This invention relates to an engine that uses intake pressure waves generated in an intake passage to obtain a supercharging effect from a medium rotation range to a high rotation range of an engine.

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 high-load intake passage, which is equipped with a high-load throttle valve and has a larger passage area than the low-load intake passage; The high-load intake port opens into the working chamber, and while maintaining the above 180° phase difference between both cylinders, each cylinder receives intake, compression, explosion, expansion, and exhaust air as the rotor rotates. The steps are performed sequentially. 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 as well, thereby increasing charging efficiency and increasing 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 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. We found that compression waves are generated in the intake port area, and (ii) expansion waves are generated in the intake passage when the intake port starts inhaling. From this, the above for one cylinder
A supercharging effect can be effectively obtained by applying the closing compression wave of (i) to the intake port of the other cylinder, especially just before fully closing, where the intake air blowback occurs (hereinafter referred to as intake interference effect). and the above for each cylinder
We discovered that a supercharging effect can be obtained by inverting the expansion wave (ii) into a compression wave and applying it to the intake port of each cylinder just before it is fully closed (hereinafter referred to as the intake-specific pulsation effect). . Among these, the above-mentioned exhaust interference effect is remarkable because, as mentioned above, in recent years, engine exhaust pressure has been increased due to the installation of catalyst devices for exhaust purification in engine exhaust systems.

In the two-system side intake port type two-cylinder rotary piston engine as described above, in order to obtain the above-mentioned exhaust interference effect and intake unique pulsation effect, the high-load intake passage and the low-load intake passage are Since there are two independent intake passages, each intake system can achieve the above effects. Among them, the intake passage for high loads has a larger passage area than the intake passage for low loads, so pressure waves can be propagated without attenuation as much as possible, and the above effect can be effectively exerted, so it is suitable for engines that require high output. It is effective to obtain an exhaust interference effect with a strong supercharging effect in the high-load intake system during high-load rotation, and it is preferable to obtain an intake-specific pulsation effect in the engine mid-speed range in the low-load 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, in which the high-load intake passages of each intake are connected to each other during each opening period of the high-load and low-load intake ports. The position of the communicating passage, the position of the expansion chamber for reversing the expansion wave generated in the low-load intake passage into a compression wave, the length of the passage between the high-load intake ports of both cylinders, and the distance from the expansion chamber to the high-load intake port of both cylinders. By appropriately setting the passage length to the low-load intake port, at high engine speeds of 5000 to 7000 rpm, which require high output, a supercharging effect can be obtained through the exhaust interference effect in the high-load intake system, and the The supercharging effect is obtained by the intake pulsation effect in the low-load intake system on the lower rotation side than the engine speed, and therefore, it is possible to achieve a supercharging effect by simply changing the design of the existing intake system without using a supercharger etc. Therefore, it is an attempt to effectively improve the output by increasing the charging efficiency from the medium rotation range to the high rotation range of the engine.

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. A low-load intake passage and a high-load intake passage having a larger passage area than the low-load intake passage are independently provided in each side housing, and each side housing has a planetary rotation movement with a phase difference of 180° at the corner. In a two-cylinder rotary piston engine that opens into the working chamber through a low-load intake port and a high-load intake port, (b) Set the opening period θp of the low-load intake port within the range of 230 to 290 degrees in rotation angle of the eccentric shaft; (c) Set the high-load intake passage of each cylinder downstream of the throttle valve. (d) providing an enlarged chamber downstream of the throttle valve in the low-load intake passage of each cylinder; (e) increasing the height of both cylinders formed by the above-mentioned communication passage and the high-load intake passage downstream thereof; The passage length Ls between the load intake ports is determined by the compression wave generated in the high-load intake passage when the high-load intake port of one cylinder is opened at high engine speeds of 5000 to 7000 rpm. Set within the range of 0.57 to 1.37 m so that the high-load intake port of the other cylinder is propagated through the communication passage to the high-load intake port just before fully closing. The passage length of the intake passage is 5000~
than the set rotation speed between 7000rpm
When the engine rotates at medium speeds of 3,500 to 5,000 rpm on the low-speed side of 1,000 rpm or more, the expansion wave generated in the low-load intake passage by the start of intake at the low-load intake port of each cylinder is reversed and reflected by the expansion chamber, resulting in a compression wave. Under the condition that the secondary pulsation wave of each cylinder is set within the range of 0.37 to 0.78 m to propagate to the low-load intake port immediately before fully closing each cylinder, Supercharging is performed by compression waves that propagate to the intake ports for high-load and high-load intakes, thereby reducing the exhaust interference effect at high engine speeds in the high-load intake system and the intake air at medium engine speeds in the low-load intake system. The unique pulsation effect effectively increases the charging efficiency from the middle to high engine speed range.

Here, 5000 ~
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, the setting of the rotation speed Nl of 3500 to 5000 rpm during engine mid-speed to obtain the intake individual pulsation effect in a low-load intake system generally requires that the maximum torque is set within this range.
In addition, it is difficult to obtain a supercharging effect due to pulsation in the low rotation range, and furthermore, if the exhaust interference effect is obtained at the reference rotation speed Nh, the effect (supercharging effect) will be lower than the reference rotation speed.
Centered on Nh, it extends to 1000 rpm higher and lower rotation than Nn, so it is at least higher than the reference rotation speed Nh above.
Obtaining the intake-specific pulsation effect on the low rotation side (Nl≦Nh−1000rpm) above 1000rp makes it possible to 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 of the communication path in the above setting item c and the expansion chamber in the expansion chamber in the above setting item d should be adjusted because the presence of the high load and low load throttle valves acts as 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 Ls between the high-load intake ports of both cylinders in the setting e above is set to effectively obtain the exhaust interference effect when the engine speed is a reference rotation speed Nh of 5000 to 7000 rpm. This is the value obtained from the formula Ls=(θs−180−θ ₀ )×(60/360Nh)×a (). That is, in the above formula, θs is the high-load intake port opening period,
θs = 270 to 320°, 180° is the phase difference between both cylinders, and θ ₀ is the period from the opening of the high-load intake port until the compression wave is substantially generated at the time of opening, and the period for effective supercharging. θ ₀ ≒ 20°, which is the ineffective period that is the sum of the period immediately before fully closing and the period immediately before fully closing the high-load intake port in which the opening compression wave is propagated in order to carry out this process.
Therefore, (θs-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 high-load intake port of the other cylinder. Also, 60/360Nh represents the time (seconds) required to rotate 1°. 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, Ls
= 0.57 to 1.37m.

Furthermore, the passage length lp between the expansion chamber and the low-load intake port of each cylinder in the above setting f is:
If the engine rotation speed is the above reference rotation speed Nh (5000~
7000rpm) 1000rpm or more on the low rotation side 3500~
It is set to effectively obtain the unique intake pulsation effect at 5000 rpm, and is calculated from the formula: lp = (θp - θl) x (60/360Nl) x a x 1/4 ... () This is the value. That is, in the above formula, the low load intake port opening period θp = 230
~290°, and propagates the secondary pulsating wave of the compression wave, which is the inversion of the expansion wave, in order to effectively supercharge the period from the opening of the low-load intake port until the expansion wave is substantially generated. This is the invalid period, which is _the sum of the period immediately before fully closing the low-load intake port and the period when it is fully closed. It represents the rotation angle of the eccentric shaft required for the next pulsating wave propagation.
Also, at engine speed Nl = 3500 to 5000 rpm, 6
0/360 ONl represents the time (seconds) required to rotate 1°. Also, the propagation speed of pressure wave a = 343 m/s
(at 20℃). Furthermore, since 1/4 uses the secondary pulsation of the pulsating wave, it represents the reciprocal of the stroke in which the secondary pulsation goes back and forth twice. Therefore, from these values, lp=0,
It will be 37 to 0.78m.

Here, in the present invention, the reason why secondary pulsation is used to obtain the intake-specific pulsation effect is that while primary pulsation has the above-mentioned effect, the passage length lp becomes too long. Since the length is twice as long as in the case of pulsation, it is not easy to install on a vehicle and tends to increase intake resistance. On the other hand, in the case of tertiary pulsation, the path length lp is shortened to 2/3 of that of secondary pulsation, but on the other hand,
The above effect is reduced by about 15 to 25% with respect to secondary pulsation, and the intake resistance does not change much. For this reason, the purpose is to effectively exhibit the intake-specific pulsation effect while shortening the passage length lp as much as possible.

Furthermore, 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 θ ₀ 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 exhaust gas from the working chamber 9 is blown back to the high-load intake port 4 side. By concentrating them, a strong compression wave is generated at the time of opening at the high-load intake port 4 to obtain a strong exhaust interference effect, and a strong expansion wave is generated at the low-load intake port 3 to create a strong intake pulsation. I'm trying to get an effect. Further, the closing timing of the high-load intake port 4 is set to be the same as or later than the closing 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 volume of the expansion chamber 28 is set to 0.5 to 2 times the engine displacement (displacement of a single working chamber x 2),
This is because if it is less than 0.5 times, the reversal effect between expansion waves and compression waves cannot be obtained, whereas if it exceeds 2 times, the pressure waves will be diffused and the unique pulsation effect of the intake air will be significantly reduced. In addition, each of the expansion chambers 26, 28
The tank functions as a surge tank during transient operations such as engine acceleration or deceleration, and ensures good fuel response.

Further, the passage length Ls between the high-load intake ports 4, 4 of the two cylinders 1A, 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 (Lp = lcs + 2ls),
Based on the above formula (), Ls is set to 0.57 to 1.37 (m) based on the high engine speed of 5000 to 7000 rpm (standard rotation speed Nh).

In addition, the first and second low-load intake passages 20
a, 20b passage length lp, that is, the opening from the opening end surface of each low-load intake passage 20a, 20b to the enlarged chamber 28 to the working chamber 9 (low-load intake port 3)
The passage length lp is 1000rpm or more lower than the standard rotational speed Nh of 5000 to 7000rpm, which is 3500 to 3500.
Based on the above equation (), Lp is set to 0.37 to 0.78 (m) based on the engine medium rotation of 5000 rpm (rotation speed Nl).

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, to explain the operation of the above embodiment with reference to FIG. 3, when the engine rotates at a high speed of 5,000 to 7,000 rpm, which requires high output, the high-load throttle valve 23 is opened to open the first and second high-load intake passages. 21a, 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. 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 closing causes each passage length Ls between the high-load intake ports 4 and 4 of both cylinders 1A and 1B to be
By setting Ls = 0.57 to 1.37m using the above formula () based on the engine high speed of 7000 rpm, the second high-load intake passage 21b → communication passage 2
5→The signal propagates through the first high-load intake passage 21a to the high-load intake port 4 of the first cylinder 1A, which has a phase difference of 180°, just before it is fully closed. As a result, this opening compression wave forces the intake air into the working chamber 9 from the high-load intake port 4 just before the first cylinder 1A is fully closed, resulting in strong supercharging. 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 4 immediately before fully closing, resulting in a strong supercharging effect.

On the other hand, during engine rotation of 3500 to 5000 rpm, which is 1000 rpm or more lower than the reference rotation speed Nh of 5000 to 7000 rpm, in each cylinder 1A and 1B, the first and second 2 Expansion waves are generated in the low-load intake passages 20a and 20b, and these expansion waves cause the passage length lp between the low-load intake port 3 and the expansion chamber 28 to be 0.37 to 0.37 by the above formula (). By setting it to 0.78m, the first and second low-load intake passages 20a, 20b
→ Expansion chamber 28 (reflects the compression wave and reflects it) → 1st,
2nd low-load intake passages 20a, 20b → low-load intake port 3 (reflected by expansion wave) → 1st,
2nd low load intake passage 20a, 20b → expansion chamber 2
8 (reflected as a compression wave) → Passes through the first and second low-load intake passages 20a, 20b, and is transmitted as a secondary pulsating wave of the compression wave to the low-load intake port of each cylinder 1A, 1B just before fully closing. 3 and supercharging is performed.

Therefore, between cylinders 1A and 1B, there is a supercharging effect due to the exhaust interference effect in the high-load intake system during high engine speeds, and an intake specific effect in the low-load intake system during medium engine speeds. Due to the supercharging effect due to the pulsation 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, compared to the conventional example in which the low-load and high-load intake passages 20a, 20b, and 21b of each cylinder 1A and 1B are made independent (indicated by a broken line), high-load operation is performed with 6000 rpm as the standard. In the case of an example of the present invention, in which an exhaust interference effect (indicated by a solid line) is obtained in the air intake system for use, and a secondary intake individual pulsation effect (indicated by a dashed-dotted line) is obtained in the intake system for low load based on 4000 rpm. Shows the output torque characteristics of the engine.

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 exhaust interference effect in the above-mentioned high-load intake system can be effectively exerted. .

In addition, each of the communication passages 25 is connected to the high load throttle valve 2.
3, and the passage area Acs of each communicating passage 25 is set to be equal to or larger than the minimum passage area As of the high-load intake passages 21a and 21b. Therefore, the pressure waves are not attenuated and the exhaust interference effect described above can be effectively exhibited. Furthermore, since the enlarged chamber 28 is located downstream of the low-load throttle valve 22, the intake-specific pulsation effect can be effectively exerted as well.

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. 4 can generate a strong compression wave when opening, and can also generate a strong expansion wave, that is, a secondary pulsating compression wave, at the low-load intake port 3, which further enhances the supercharging effect due to the exhaust interference effect and the intake unique pulsation effect. It can be made powerful.

In addition, the supercharging effect due to the exhaust interference effect and the intake individual pulsation effect is caused by the opening periods θp, θs of the low-load and high-load intake ports 3, 4, the first high-load intake passage 21a and the second high-load intake passage. The position of the communication passage 25 that communicates with the air intake passage 21b, the position of the enlarged chamber 28 of the low-load intake passages 20a and 20b, the passage length Ls between the high-load intake ports 4 and 4 of both cylinders 1A and 1B, and This can be achieved by setting the passage length lp between the expansion chamber 28 and the low-load intake port 3 as described above, and since a supercharger or the like is not required, the design of the existing intake system can be reduced. It requires only a few changes, has a very simple structure, and can therefore 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.

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 exhaust interference effect between the cylinders in the high-load intake system, and
1000pm higher than the standard rotation speed of 5000~7000rpm above
As mentioned above, when the engine rotates at medium speeds of 3500rpm to 5000rpm on the low-speed side, the supercharging effect is obtained by the intake pulsation effect of each cylinder itself in the low-load intake system, so there is no need for a supercharger etc. Even with a simple configuration that involves slight design changes to the intake system, it is possible to effectively improve the output by increasing the filling efficiency from the mid- to high-speed range of the engine, thereby improving the output of the rotary piston engine. This can greatly contribute to easier implementation of countermeasures 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, 28...expansion chamber.

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 intake passage for low load and the intake passage for high load, which have a larger passage area than the intake passage for low load, are independent from each other. In a two-cylinder rotary piston engine that opens into the working chamber through low-load and high-load intake ports provided in each side housing, a. b. Set the opening period of the low-load intake port to a range of 230-290° based on the rotation angle of the eccentric shaft. c. Set the high-load intake passage of each cylinder to a throttle valve. d. Providing an enlarged chamber downstream of the throttle valve of the low-load intake passage of each cylinder; e. Both cylinders formed by the above-mentioned communication passage and the high-load intake passage downstream thereof. The compression wave generated in the high-load intake passage when the high-load intake port of one cylinder is opened at high engine speed when the passage length between the high-load intake ports is set between 5000 and 7000 rpm is as shown above. Set within the range of 0.57 to 1.37 m so that the high-load intake port of the other cylinder is propagated through the communication passage to the high-load intake port just before fully closing. Set the length of the intake passage to 5000~
1000rpm than the set rotation speed between 7000rpm
When the engine rotates at a low speed of 3,500 to 5,000 rpm, the expansion wave generated in the low-load intake passage by the start of intake at the low-load intake port of each cylinder is reversed and reflected by the expansion chamber, resulting in a compression wave. Under the condition that the secondary pulsation wave is set within the range of 0.37 to 0.78 m so that the secondary pulsation wave propagates to the low-load intake port just before each cylinder is fully closed, the low-load intake port just before each cylinder is fully closed An intake device for a rotary piston engine, characterized in that supercharging is performed by compression waves propagated to the intake port for high load and the intake port for high load.