JPH055222Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an engine equipped with a pressure wave supercharger.

(Prior Art) FIG. 2 shows a system diagram of a conventional general engine with a pressure wave supercharger. In the figure, reference numeral 1 indicates the engine body and 2 indicates the pressure wave supercharger.

The pressure wave supercharger 2 includes a rotor 21 that is rotatably fitted into a cylindrical rotor housing 22 and has a large number of small chambers (not shown) that are open on both axial end faces. To,
The air casing 23 has an air passage (not shown) communicating with the small chamber, and the gas casing 24 has a gas passage (not shown) communicating with the small chamber. . The pressure wave supercharger 2 also has an air casing 23 connected to an intake passage 3 communicating with the intake port of the engine body 1, and a gas casing 24 connected to an exhaust passage 4 communicating with the exhaust port of the engine body 1. It can be assembled on the engine side while connected. The pressure wave supercharger 2 is configured to exhaust air by bringing the intake air A flowing through the air casing 23 and the exhaust gas G flowing through the gas casing 24 into contact with each other in each small chamber of the rotor 21. This compresses (supercharges) intake air using gas pressure waves.

In this case, when the pressure wave supercharger is operated when the engine is started or in a low-speed/low-load operating range, the engine speed is low, so there is a gap between the exhaust gas and the intake air in each chamber of the pressure wave supercharger 2. The exchange of pressure waves becomes slow, and there is concern that not only the compression effect of the intake air will be extremely reduced, but also problems such as exhaust gas flowing back into the intake passage 3 through the small chamber and worsening combustibility will occur. For this reason, the second
As shown in the figure, an intake bypass passage 5 is provided in the intake passage 3 to bypass the pressure wave supercharger 2, and the intake bypass passage 5 is provided in the intake passage 5 during engine startup and in low speed/low load operating regions. By opening the valve 50 and introducing intake air from the intake bypass passage 5, the above-mentioned problems are prevented from occurring. In this case, the intake side bypass valve 50 is a check valve 51 that allows bypass intake air to flow to the engine body side.
and a shutter valve 52 which is operated according to the intake pressure on the downstream side of the pressure wave supercharger 2 and selectively opens and closes the intake passage 3 and the intake bypass passage 5. When starting the engine and in low-speed/low-load operating ranges, the shutter valve 52 is set to the valve position (hereinafter referred to as the first valve position) shown by the chain line (reference numeral 52'), and the intake air is placed in the engine's intake vacuum. The check valve 51 is opened by the pressure, and the air is introduced directly into the engine body 1 from the intake bypass passage 5. On the other hand, in the high speed/high load operating range of the engine, the compression action of the pressure wave supercharger 2 increases and the intake pressure in the intake passage 3 increases, so the shutter valve 52 opens due to the intake pressure. It is urged to rotate toward the valve side and is positioned at a valve position (hereinafter referred to as a second valve position) that closes the intake bypass passage 5, as shown by a solid line in FIG. Therefore, in this case, the intake air pressurized by the pressure wave supercharger 2 is directly introduced into the engine body 1 side from the intake passage 3, and a supercharging effect is realized. Note that, after the shutter valve 52 is opened, the solenoid 55 attracts and fixes the shutter valve 52 to maintain its open state.

On the other hand, also on the exhaust passage 4 side, an exhaust bypass passage 6 that bypasses the pressure wave supercharger 2 is normally provided, and an exhaust side bypass valve 54 that opens and closes the exhaust bypass passage 6 is further provided in this exhaust bypass passage 6. provided. The exhaust side bypass valve 54 is used as a waste gate valve to prevent supercharging by the pressure wave supercharger 2, and in an operating region where the pumping loss of the engine increases, the pressure wave supercharger 2 It is conceivable that the valve could be used as a control valve to reduce pumping loss by disabling the operation of the valve. When the exhaust side bypass valve 54 is used as a wastegate valve, it is opened appropriately in the high speed/high load operating region of the engine to open the exhaust bypass passage 6 (this valve position is set to the first valve position). position), and in other operating ranges, it is closed to close the exhaust bypass passage 6 (this valve position is referred to as the second valve position).
This control characteristic is adopted. On the other hand, when the exhaust side bypass valve 54 is used as a control valve, it is opened to open the exhaust bypass passage 6 in the engine's low-speed and low-load operating range, and is closed in the high-speed and high-load operating range. A control characteristic of closing the exhaust bypass passage 6 is adopted.

Therefore, for example, in an engine equipped with a pressure wave supercharger in which the exhaust side bypass valve 54 is used as a control valve, the exhaust side bypass valve 54 and the intake side bypass valve 50 on the side of the intake bypass passage 5 are
The operating ranges of the two will match. That is, the third
The two bypass valves 50 and 54 are both closed in a high-speed, high-load operating region indicated by region A in the figure, and are both opened in a low-speed, low-load operating region indicated by region B. In addition, in FIG. 3, the curve L is the maximum output line of the engine.

By the way, in a pressure wave supercharged engine equipped with such a pressure wave supercharger 2, high frequency noise is generated due to the characteristics of the pressure wave supercharger 2. That is, when the rotor 21 of the pressure wave supercharger 2 rotates,
Air casing 2 with which the rotor 21 faces
The rotor 21, the air casing 23, and the gas Since the facing gap with the casing 24 is set as small as possible, high-frequency noise similar to wind noise is generated, and this is radiated to the outside through the intake passage or the exhaust passage.
Contributes to driving noise.

For this reason, in general, an engine equipped with a pressure wave supercharger is provided with an absorption type muffling device in both the intake system and the exhaust system, and the above-mentioned noise is attenuated by the muffling action of these devices. Specifically, as shown in FIG. 2, in the intake system, an inner cylindrical member 34 made of punched metal is disposed inside the air cleaner body 32 of the air cleaner 31 in a double cylindrical shape, and the air cleaner body 32 and inner cylinder member 3
A sound absorbing material 35 made of glass wool, stone wool, or the like is filled in the gap between the sound absorbing material 4 and the sound absorbing material 35, thereby absorbing and attenuating the noise. In addition, in FIG. 2, the reference numeral 33 is an air element.

Further, in the exhaust system, an exhaust side muffler 41 is installed at a downstream position of the exhaust passage 4, and the noise is attenuated by the muffling action of this exhaust side muffler 41. This exhaust side muffler 41 also has a muffler main body 42 and a muffler main body 4, similar to the air cleaner 31 described above.
A sound absorbing material 44 is filled in an annular gap between the inner cylinder member 43 made of bunching metal located inside the inner cylinder member 2.

However, the frequency range in which the sound damping effect can be obtained by using only such absorption type sound damping devices is narrow, and if moisture or carbon adheres to the sound absorbing material, the sound damping effect will be greatly reduced. It cannot be said that the device has a sufficient silencing effect.

Furthermore, in order to enhance the silencing effect, it is conceivable to provide the intake/exhaust system with, for example, a resonance type silencing device in addition to the silencing device described above, but this may lead to an increase in the size of the device and is not practical.

Incidentally, a known example in which a bypass passage for bypassing the pressure wave supercharger is provided in the intake passage of an engine equipped with a pressure wave supercharger and a bypass valve for opening and closing the bypass passage is attached is, for example, -There is something disclosed in Publication No. 1153.

(Purpose of the invention) The present invention is an attempt to solve the problems pointed out in the above-mentioned section of the prior art. The purpose of this technology is to effectively reduce the noise generated from the pressure wave supercharger in engines while minimizing the size of the device, thereby realizing quiet operation of the entire engine device. be.

(Technical background of the invention) In the process of researching a noise reduction method for such an engine equipped with a pressure wave supercharger, the inventor of the present invention focused on the cause of noise specific to a pressure wave supercharger. In other words, the noise peculiar to a pressure wave supercharger is caused by the viscosity of air when the rotor and air casing or gas casing face each other with a small gap in the rotor housing of the pressure wave supercharger and rotate relative to each other at high speed. This is due to resistance. Therefore, there should be some correlation between the rotor rotational speed (ie, engine rotational speed), the amount of circulating air (ie, engine load), and the noise level.
Based on this idea, the inventor of the present invention experimentally determined the correlation among the engine load, engine speed, and noise level, and this is shown in FIG. 4.

In FIG. 4, curve L is the maximum output line of the engine. Further, curves _l1 to _l5 are equal level curves of noise generated from the pressure wave supercharger portion, and the noise level gradually increases from curve _l1 to curve _l5 . In other words, from Fig. 4, the noise level is low in the low-speed/low-load operating range, including when the engine is started, and there is little demand for noise reduction, but the noise level is low in the high-speed/high-load operating range of the engine. It can be said that the noise reduction is very high and therefore there is a great demand for noise reduction.

Here, the inventors of the present invention have compared and considered the noise equal level curve shown in FIG. 4 with the operating range diagram of the bypass valve shown in FIG. The high-speed, high-load operating region A where both are closed corresponds to the operating region where a high level of noise occurs and where noise reduction is particularly required (for example, region C on the higher level side than curve _l1 in Fig. 4). , and at low speeds where both the intake bypass passage 5 and the exhaust bypass passage 6 are open.
The low-load operating region B matches the operating region where the noise level is low and there is little demand for noise reduction (for example, region D on the lower level side of curve _l1 in Fig. 4) (in other words, there is a large demand for noise reduction). In the operating region, both the intake bypass passage 5 and the exhaust bypass passage 6 are closed, and the intake bypass passage 5 and the exhaust bypass passage 6 do not function effectively in terms of engine operation, but in the operating region where noise reduction is not required. found that both the intake bypass passage 5 and the exhaust bypass passage 6 are open, and the intake bypass passage 5 and the exhaust bypass passage 6 function effectively as the original bypass passage.

For this reason, the inventors of the present application have proposed that the intake bypass passage 5 or the exhaust bypass passage 5, both of which are closed and do not function effectively for engine operation (in other words, are in an idle state) in the low-speed and low-load operating range of the engine. The idea was to minimize the size of the device by making the passage 6 function as a resonant muffler, and to reduce the noise peculiar to a pressure wave supercharger as much as possible.

(Means for Achieving the Object) As a means for achieving the above object, the present invention has a rotor in which a large number of small chambers opening on both axial end faces are arranged circumferentially and is rotatably fitted into a rotor housing. At the same time, an air casing having an air passage that can communicate with the small chamber and a gas casing having a gas passage that can communicate with the small chamber are attached to both axial ends of the rotor housing, respectively. The air casing is connected to an intake passage of the engine, and the gas casing is connected to an exhaust passage of the engine, and at least one of the intake passage and the exhaust passage is connected to an intake passage on the upstream side of the pressure wave supercharger. A bypass valve that communicates with an intake passage downstream of the pressure wave supercharger to form a bypass passage that bypasses the pressure wave supercharger, and that opens the bypass passage in a specific operating region of the engine. In the engine with a pressure wave supercharger, a volume expansion chamber is formed in the bypass passage, and the bypass valve is arranged at a position on the intake downstream side or exhaust upstream side of the volume expansion chamber in the bypass passage. This is what I did.

(Function) In the present invention, by the above means, (1) In the operating region where the bypass valve is in the open state, intake air flows through the bypass passage bypassing the pressure wave supercharger; (2) Bypass In an operating region where the valve is in a closed state, a resonant type system is used in which one end of the bypass passage and the volume expansion chamber formed in the bypass passage opens into the intake passage on the upstream side of the pressure wave supercharger. A silencing device is constructed, and the resonance type silencing device effectively attenuates noise generated from the pressure wave supercharger.

(Embodiment) Hereinafter, a preferred embodiment of the present invention will be described with reference to FIG.

The pressure wave supercharged engine of this embodiment has an intake bypass passage 5 provided in the intake passage 3 and an exhaust passage 4 provided in the intake passage 3.
The exhaust bypass passage 6 provided in the exhaust bypass passage 6 functions as a part of an intake side resonance type muffler 11 and an exhaust side resonance type muffler 12, which will be described later, respectively, and its basic structure is that of each resonance type muffler. All parts except for the devices 11 and 12 are the same as the pressure wave supercharged engine of the prior art example (see FIG. 2). Therefore, here, this intake side resonance type muffler 11 and the exhaust side resonance type muffler 12
Only the structure and operation thereof will be described in detail, and explanations of other constituent members will be omitted by assigning the same reference numerals to each member in FIG. 1 in correspondence with each member in FIG. 2.

The intake bypass passage 5 is provided in the intake passage 3 so as to bypass the pressure wave supercharger 2, and at its intake downstream end there is an intake side bypass consisting of a check valve 51 and a shutter valve 52 as described above. A valve 50 is installed. As described above, the intake side bypass valve 50 opens in response to the intake pressure on the downstream side of the pressure wave supercharger 2 to open the intake bypass passage 5 in the low speed/low load operating region of the engine. The operating characteristics are set so that the valve is closed and the intake bypass passage 5 is closed in a high speed/high load operating region.

Furthermore, a volume expansion chamber 7 having an appropriate volume is provided at a position upstream of the intake side bypass valve 50 in the intake bypass passage 5 so as to surround the outside of the intake bypass passage 5. There is. In addition, a plurality of openings 9, 9, . This means that each hole 9,
They are communicated with each other via 9... Therefore, when the intake side bypass valve 50 is in the closed state, the volume expansion chamber 7 is a closed space that opens only on the upstream side of the intake bypass passage 5.

Incidentally, the diameter of the apertures 9 and the number of the apertures 9 formed are determined depending on the resonance frequency of the noise to be muffled by utilizing the resonance damping effect. In particular, in the case of this embodiment, the resonance frequency is set to a frequency range other than the noise frequency absorbed and attenuated by the air cleaner 31 and the exhaust side muffler 41, and both the resonance damping effect and the absorption damping effect are effectively utilized. This makes it possible to obtain effective noise reduction over a wider frequency range.

That is, in this embodiment, by closing the intake side bypass valve 50 and making the intake bypass passage 5 a closed passage with one end closed, the volume of the intake bypass passage 5 and the area located outside thereof is expanded. An intake side resonance type silencer 11 having a double cylindrical shape with the chamber 7
It consists of

On the other hand, on the exhaust passage 4 side, a volume expansion chamber 8 having the same structure as the volume expansion chamber 7 on the intake bypass passage 5 side is provided in the exhaust bypass passage 6 that bypasses the pressure wave supercharger 2, and the exhaust bypass passage 6
An opening 10 is provided in a portion corresponding to the volume expansion chamber 8,
10... is formed. Therefore, in this case as well, similarly to the above-mentioned intake system, the exhaust side bypass valve 54 disposed at the exhaust upstream end of the exhaust bypass passage 6 is closed to close the exhaust bypass passage 6 with one end thereof closed. By forming a passage, the exhaust bypass passage 6 and the volume expansion chamber 8 located outside thereof constitute an exhaust side resonance type muffler 12.

In this embodiment, the exhaust side bypass valve 54 is made to function as a control valve as described above, from the viewpoint of effectively utilizing the exhaust side resonance type muffler 12 for noise reduction. Therefore, this exhaust side bypass valve 54 is opened in the low speed and low load operating range of the engine, and is opened in the high speed and low load operating range of the engine.
The valve is closed in high load operating ranges.

In this way, the intake bypass passage 5 and the exhaust bypass passage 6 are provided with an intake side resonance type muffler 11 and an exhaust side resonance type muffler 12, respectively, which function as a resonance type muffler in the high speed/high load operating region of the engine. In an engine equipped with a pressure wave supercharger, the intake side resonance type muffler 11 and the exhaust side resonance type muffler 12 are used in the high speed/high load operation region of the engine where the noise generated from the pressure wave supercharger 2 increases. Both function effectively as a silencer,
Among the noises exhausted from the pressure wave supercharger 2, noises of a specific frequency are effectively attenuated by resonance.
For this reason, the absorption and damping effect by the air cleaner 31 having an absorption damping function provided in the intake passage 3 and the exhaust side muffler 41 provided in the exhaust passage 4 and the above-mentioned intake side resonance type muffler 11 and exhaust side resonance type device 12 are achieved.
Due to the synergistic effect with the resonance damping effect, a high level of silencing effect can be obtained in a wider frequency range.

On the other hand, in the low-speed/low-load operating region of the engine, the intake bypass passage 5 and the exhaust bypass passage 6 are each opened, so that neither the intake side resonance type muffler 11 nor the exhaust side resonance type muffler 12 is configured, and the intake bypass passage 5 and the exhaust bypass passage 6 are respectively opened. The bypass passage 5 and the exhaust bypass passage 6 function as the original bypass intake and bypass exhaust passages, respectively. Therefore, in this operating region, the intake side resonance type muffler 11 and the exhaust side resonant type muffler 12 do not perform any resonance damping of noise, but originally this operating region is affected by the noise generated from the pressure wave supercharger 2. Since the level itself is in a low range, there is no particular problem in terms of engine operating noise.

In addition, in this embodiment, the intake side resonance type muffler 11 and the exhaust side resonance type muffler 12 utilize a part of the intake bypass passage 5 and the exhaust bypass passage 6, respectively, which are indispensable for the operating characteristics of the engine. Since it has a simple and compact configuration in which the volume expansion chamber 7 or 8 is added to the 2D air filter, compared to the case where a dedicated resonance type muffler is installed separately from the intake bypass passage 5 or the exhaust bypass passage 6. (In other words, it is possible to minimize the increase in size of the device due to the provision of a resonance type muffling device), and the degree of freedom in layout when the engine is mounted on a vehicle is improved. Benefits such as:

(Effects of the invention) The present invention has a rotor that is rotatably fitted into a rotor housing, in which a large number of small chambers that are open on both axial end faces are arranged in the circumferential direction, and that the small chambers are provided at both axial ends of the rotor housing. A pressure wave supercharger is provided with an air casing having a communicating air passage and a gas casing having a gas passage communicating with the small chamber. connected to the exhaust passages of the engine, and further communicates at least the intake passage upstream of the pressure wave supercharger and the intake passage downstream of the pressure wave supercharger in the intake passage and the exhaust passage. In an engine with a pressure wave supercharger, the bypass passage is provided with a bypass valve that opens the bypass passage in a specific operating region of the engine. A volume expansion chamber is formed therein, and the bypass valve is disposed in the bypass passage at a position on the intake downstream side of the volume expansion chamber.

Therefore, according to the pressure wave supercharged engine of the present invention, (1) the bypass valve provided in the bypass passage can be closed in the high speed/high load operation region of the engine where the noise from the pressure wave supercharger becomes large; The bypass passage and the volume expansion chamber 7 provided outside it
This constitutes a resonance type muffler, one end of which opens in the intake passage upstream of the pressure wave supercharger, so some of the noise generated from the pressure wave supercharger is resonantly attenuated in this resonance part. The above noise is effectively attenuated and muffled over a wide frequency range by the synergistic effect with the noise absorption and attenuation effect of the absorption type silencer provided in the intake passage and the exhaust passage, respectively, and the engine system as a whole is improved. (2) Since the bypass passage, which is essential for engine operating performance, is used as part of the resonance type silencer, the increase in size of the device is kept to a minimum. Practical effects such as a high level of noise reduction effect can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of an engine with a pressure wave supercharger according to an embodiment of the present invention, Fig. 2 is a system diagram of an engine with a pressure wave supercharger of a conventional structure, and Fig. 3 is a diagram of the operating area of the bypass valve. , FIG. 4 is a noise level characteristic diagram. 1...Engine body, 2...Pressure wave supercharger, 3
...Intake passage, 4...Exhaust passage, 5...Intake bypass passage, 6...Exhaust bypass passage, 7, 8...
Volume expansion chamber, 9, 10... Hole, 21... Rotor, 22... Rotor housing, 23... Air casing, 24... Gas casing, 31... Air cleaner, 33... Air element, 41...
Exhaust side silencer, 50, 54...Bypass valve, 51
...Check valve, 52...Shutter valve, 55...
…solenoid.

Claims (1)

[Scope of utility model registration request] A rotor having a plurality of small chambers arranged circumferentially that are open on both axial end faces is rotatably fitted into a rotor housing, and air passages that can communicate with the small chambers are formed at both axial ends of the rotor housing. The air casing of the pressure wave supercharger is constructed by attaching a casing and a gas casing forming a gas passage that can communicate with the small chamber, and the air casing is connected to the intake passage of the engine, and the gas casing is connected to the exhaust passage of the engine. Further, of the intake passage and the exhaust passage, at least the intake passage on the upstream side of the pressure wave supercharger and the intake passage on the downstream side of the pressure wave supercharger are communicated with each other to provide pressure wave supercharging. In an engine equipped with a pressure wave supercharger, the engine is equipped with a bypass valve that opens the bypass passage in a specific operating region of the engine, and the bypass passage is provided with a bypass valve that opens the bypass passage in a specific operating region of the engine. An engine with a pressure wave supercharger, characterized in that the bypass valve is disposed at a position on the intake downstream side of the volume expansion chamber of the bypass passage.