JPS6237213B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an intake system for a rotary piston engine, and more particularly, the present invention relates to an intake system for a rotary piston engine. This invention relates to a device that uses intake pressure waves to obtain a supercharging effect when the engine is under high load and high rotation speed.

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 housings located on both sides of the rotor housing. A roughly 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 is connected to a low-load intake passage equipped with a low-load throttle valve and a low-load intake passage equipped with a low-load throttle valve. A high-load intake passage equipped with a 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 cylinders sequentially perform the intake, compression, explosion, expansion, and exhaust strokes 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 and intake air is supplied only from the low-load intake passage, thereby increasing the intake flow rate and improving combustion stability. When under load, the high-load throttle valve is also opened to supply intake air from the high-load intake passage, increasing filling efficiency and increasing output. This is the so-called dual induction system. It is something. 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.

Furthermore, 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 was divided into two passages with different dimensions. 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.
It is around 400 to 600 mmHg (gauge pressure), and in turbocharged engines it is over 1000 mmHg.
Improvement in filling efficiency by the peripheral port method cannot be expected.

Therefore, when examining the intake characteristics of the side intake port in a rotary piston engine, the present inventors found that 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 intake port portion in the intake passage It was discovered that compression waves are generated. From this, it can be seen that if the compression wave at the time of opening in one cylinder is applied to the intake port of the other cylinder, especially just before the intake port is fully closed, where the intake air blowback occurs, an effective supercharging effect can be obtained (hereinafter referred to as , the exhaust interference effect). and,
As mentioned above, this exhaust interference effect is remarkable because 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, the high-load intake passage and the low-load intake passage are separated by two independent passages.
Since the system has intake passages, it is possible to obtain an exhaust interference effect in each intake system, which is effective.

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 of each cylinder. 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 strong supercharging effect is obtained due to the mutual effect of the exhaust interference effect in the high-load intake system and the exhaust interference effect in the low-load intake system, and therefore the existing intake air can be used without using a supercharger etc. The aim is to significantly and effectively improve the output by significantly increasing the charging efficiency at high engine load and high rotation speeds through a simple configuration with slight design changes to the 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 low-load intake passage and the high-load intake passage are independently provided in each side housing downstream of the low-load throttle valve. In a two-cylinder rotary piston engine in which a high-load intake port 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 degrees in rotation angle of the eccentric shaft. (b) Setting the opening period θ _p of the low-load intake port within the range of 230 to 290 degrees in rotation angle of the eccentric shaft; (c) Connecting the high-load intake passage of each cylinder to the high-load connection downstream of the throttle valve. (d) The low-load intake passages of each cylinder are connected by a low-load communication passage downstream of the throttle valve; (e) The above-mentioned high-load communication passage and the high-load intake passage downstream thereof are formed. The passage length L _s between the high-load intake ports of both cylinders is set to 5000~
When the engine rotates at a high speed of 7000 rpm, the opening compression wave generated in the high-load intake passage when the high-load intake port of one cylinder is opened is transferred to the high-load intake port of the other cylinder through the high-load communication passage. Set within the range of 0.57 to 1.37m so as to propagate to the load intake port; The passage length L _p between ports is 5000~
When the engine rotates at a high speed of 7000 rpm, the compression wave generated in the low-load intake passage when the low-load intake port of one cylinder is opened is transferred to the low-load intake passage just before the other cylinder is fully closed, via the low-load communication passage. Under the condition that the distance is set within the range of 0.25 to 1.03m so that the wave propagates to the intake port, supercharging is generated by the compression wave that propagates to the low-load and high-load intake ports just before each cylinder is fully closed. Therefore, due to the mutual effect of the exhaust interference effect between the cylinders in the high-load intake system and the exhaust interference effect between the cylinders in the low-load intake system, the intake air immediately before each intake port is fully closed is reduced. This suppresses blowback and effectively and significantly increases filling efficiency.

Here, the limitation of 5000 to 7000 rpm as the engine high speed to obtain the above exhaust interference effect is because the maximum output and maximum speed are generally set within this range. This depends on the fact that it requires a lot of power and is an effective area for improving filling efficiency and power.

In addition, the upper limit of the high-load intake port opening period θ _s 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 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.

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 θ _p of the low-load intake port is set to 230 to 290° 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 outside the side seal has no substantial effect on the generation and propagation of effective pressure waves in the high rotation range, which is the problem of the present invention.

In addition, the downstream position setting of the throttle valve of the high-load communication passage in the above setting c and the low-load communication passage in the above setting d is the throttle valve that controls the air flow rate of the high-load and low-load intake passages. This is to avoid the presence of , which acts as a resistance to the propagation of pressure waves, and to propagate the pressure waves effectively by reducing their attenuation.

Furthermore, the passage length L _s between the high-load intake ports of both cylinders in the above setting e and the passage length L _p between the low-load intake ports of both cylinders in the above setting f are 5000 to 7000 rpm. It is set to effectively obtain the exhaust interference effect at high engine speeds, L _s(P) = (θ _s(P) −180−θ _p ) × (60/360N) × a ……( ) is the value obtained from the formula. That is, in the above formula, θ _s and θ _p are θ _s = 270 to 320° and θ _p = 230 during the intake port opening period for high load and low load.
~290°, 180° is the phase difference between both cylinders, and θ _p is the period from the opening of each intake port until the compression wave is substantially generated at the time of opening, and the period for effective supercharging. The ineffective period is the sum of the period from just before fully closing to the period when each intake port is fully closed, which propagates the opening compression wave, and θ _p ≒20°, so (θ _s(P) −180 − θ _p ) 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, N is the engine speed and N=
5000 to 7000 rpm, and 60/360N 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, L _s
=0.57~1.37m, L _p =0.25~1.03m.

Note that in the above equation (), the influence of the flow of intake air on the propagation of pressure waves is ignored. this is,
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 for low load and high load use, and each cylinder
A and 1B each have a two-section trochoidal inner peripheral surface 2a.
The rotor housing 2 includes 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 (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, and rotors 7, 7 of each cylinder 1A, 1B. is the rotation angle of eccentric shaft 8.
With a phase difference of 180°, three working chambers 9, 9, 9 move inside the casing 6 as each rotor 7 rotates.
In each cylinder 1A, 1B, the above
The intake, compression, explosion, expansion, and exhaust strokes are performed sequentially with a phase difference of 180°. 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 surface 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.

Above low load and high load intake ports 3, 4
is opened and closed by the side surface of the rotor 7, and the opening period θ _s 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. The period θ _p is 230
It is set in the range of ~290°. Further, the opening timing of the high-load intake port 4 is set to be approximately the same time as the opening timing of the low-load intake port 3, and the closing timing of the high-load intake port 4 is set to the closing timing of the low-load intake port 3. It is set to be at the same time as or later than that.

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 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 at low engine loads. A throttle valve 22 is provided in the main high-load intake passage 21.
A high-load throttle valve 23 is provided that opens when the engine load exceeds a predetermined load and controls the intake air amount during high engine load. 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 is branched into first and second low-load intake passages 20a and 20b for each cylinder 1A and 1B. The main high-load intake passage 21 communicates with the working chambers 9, 9 through the intake ports 3, 3, and the main high-load intake passage 21 has first and second high-load intake passages 21 having the same shape and dimensions downstream of the high-load throttle valve 23.
a, 21b, and then into the working chambers 9, 9 via the high-load intake ports 4, 4 of each cylinder 1A, 1B.
Therefore, for each cylinder 1A, 1B, the low load intake passages 20a, 20b and the high load intake passages 21a, 21b are connected to the low load throttle valve 22.
They are each configured to open into the working chamber 9 independently on the downstream side.

The minimum passage area A _s of each of the above-mentioned high-load intake passages 21a, 21b is
larger than the minimum passage area A _p of b (A _s > A _p )
and each high-load intake passage 21a, 21
The passage length l _s of b is for each low-load intake passage 20a,
20b is shorter than the passage length l _p (l _s <l _p )
The high load intake passages 21a, 21
The propagation of the compression wave due to the exhaust interference effect due to b is made more effective by reducing its attenuation. Further, 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 18 are arranged in each of the low-load intake passages 20a, 20b, respectively. ing.

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 a high load expansion chamber 26 having a high load communication passage 25 that communicates with b. The passage area Acs of the high-negative communication passage 25 is set to the first and second high-load intake passages 2 so as to reduce the 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 1a 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. Low load communication path 27
It is constituted by a low load expansion chamber 28 having a. The passage area A _cp of the low-load communication passage 27 is set so that the first and second
It is set to be equal to or larger than the minimum passage area A _p of the low-load intake passages 20a and 20b (A _cp ≧A _p ). 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 L _s between the high-load intake ports 4 and 4 of the two cylinders 1A and 1B is the passage length L _cs of the high-load communication passage 25 and the first and second passages downstream of the communication passage 25. The sum of the passage lengths l _s and _ls of the high-load intake passages 21a and 21b (L _s = l _cs +
2l _s ), and from the above formula (), L _s is set to approximately 0.57 to 1.37 (m) based on the engine high rotation of 5000 to 7000 rpm.

In addition, the passage length L _p between the low-load intake ports 3 and 3 of the two cylinders 1A and 1B is equal to the passage length l _cp of the low-load communication passage 27 and the first and second ports downstream of the communication passage 27. 2 The sum of the passage lengths l _p and l _p of the low-load intake passages 20a and 20b (L _p = l _cp +
2l _p ), and L _p is set to 0.25 to 1.03 (m) from the above formula () based on the engine high rotation of 5000 to 7000 rpm.

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. At the same time, the low-load intake port 3 of the second cylinder 1B
At the time of opening, a compression wave is generated in the low-load intake port 3 portion within the low-load intake passage 20b. These opening compression waves are generated in both cylinders 1A and 1, respectively.
The passage lengths L _s and L _p between the high-load intake ports 4 and 4 and between the low-load intake ports 3 and 3 of B are shown above.
Based on the above equation (), L _s = 0.57 to 1.37 m, L _p = based on the high engine speed of 5000 to 7000 rpm.
By setting it to 0.25 to 1.03 m, the second high-load or second low-load intake passages 21b and 20b, respectively.
→ High load or low load communication path 25, 27 → 1st
High load or first low load intake passage 21a, 20
a, and propagates to the high-load intake port 4 and low-load intake port 3 of the first cylinder 1A, which has a phase difference of 180 degrees, just before fully closing. As a result, these opening compression waves force intake air into the working chamber 9 from the high-load intake port 4 and the low-load intake port 3 just before the first cylinder 1A is fully closed, and strong supercharging is performed. It turns out. Similarly, in the second cylinder 1B, the opening compression wave from the first cylinder 1A is propagated to the high-load intake port 4 and the low-load intake port 3 just before fully closing, respectively, resulting in a strong supercharging effect. can get.

Therefore, between the cylinders 1A and 1B, there is a supercharging effect due to the exhaust interference effect on the high-load intake port 4 just before the high-load intake system is fully closed, and a supercharging effect due to the exhaust interference effect on the high-load intake port 4 immediately before the high-load intake system is completely closed. As shown in Figure 4, due to the interaction effect with the supercharging effect due to the exhaust interference effect on the low-load intake port 3 immediately before, the charging efficiency is significantly increased at high engine load and high rotation speeds (5000 to 7000 rpm). The output can be greatly improved by increasing the output power. In addition, in Fig. 4, each cylinder 1
A, 1B low load and high load intake passages 20
In contrast to the conventional case where a, 20b, 21a, and 21b are independent (indicated by the broken line), the exhaust interference effect (indicated by the dashed line) is obtained in the low-load intake system based on 6000 rpm, and the high 2 shows the output torque characteristics of the engine in the case of an example of the present invention (indicated by a solid line) in which an exhaust interference effect is obtained in the load intake system.

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. .

Further, each of the communication passages 25 and 27 is connected to each throttle valve 2.
2, 23 downstream, and each communication path 25,
Since the passage areas A _cs and A _cp of No. 27 are made equal to or greater than the minimum passage areas A _s and A _p of the high-load and low-load intake passages 21a, 21b, 20a, and 20b,
The pressure waves are not attenuated by the throttle valves 22, 23 or the communicating passages 25, 27 themselves, so that the exhaust interference effect in the intake systems can be effectively exerted.

Furthermore, the supercharging effect due to the exhaust interference effect allows the high-load intake passages 21a, 21b and the low-load intake passages 20a, 20b to communicate with each other during the opening period of the low-load and high-load intake ports 3, 4. The position of each communication passage 25, 27 and both cylinders 1A, 1
This can be obtained by setting the passage lengths L _{s and} L _p between the high-load intake ports 4 and 4 and between the low-load intake ports 3 and 3 of B as described above, and does not require a supercharger or the like. Therefore, only a slight design change to the existing intake system is required, 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, 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 with two systems for low load and high load, 5000
At high engine speeds of ~7000 rpm, a strong supercharging effect is achieved through the mutual effect of the exhaust interference effect between cylinders in the high-load intake system and the exhaust interference effect between cylinders in the low-load intake system. Therefore, even with a simple configuration that requires only a slight design change to the existing intake system without the need for a supercharger, it is possible to significantly increase the charging efficiency under high load and high engine rotation speeds, effectively increasing the 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, 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...High load communication passage, 27
...Low load communication path.

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. Setting the opening period of the load intake port to a range of 230 to 290 degrees in rotation angle of the eccentric shaft; c. Connecting the high load intake passages of each cylinder with a high load communication passage downstream of the throttle valve; d) connecting the low-load intake passages of each cylinder with a low-load communication passage downstream of the throttle valve; e) increasing the height of both cylinders formed by the above-mentioned high-load communication passage and the high-load intake passage downstream thereof; The passage length between the load intake ports is 5000 to 7000rpm.
When the engine rotates at high speed, the compression wave generated in the high-load intake passage when the high-load intake port of one cylinder is opened is transferred to the high-load intake of the other cylinder just before it is fully closed, via the high-load communication passage. Set within the range of 0.57 to 1.37m so as to propagate to the port; Passage length, 5000~7000rpm
When the engine rotates at high speed, the compression wave generated in the low-load intake passage when the low-load intake port of one cylinder is opened is transferred to the low-load intake of the other cylinder just before it is fully closed, via the low-load communication passage. Under the condition that the distance is set within the range of 0.25 to 1.03 m so that the waves propagate to the ports, supercharging is performed by the compression waves that propagate to the low-load and high-load intake ports just before each cylinder is fully closed. An intake device for a rotary piston engine characterized by the following features: