JPH055221Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a supercharging pressure control structure in an intake passage of a supercharged internal combustion engine.

<Prior art> It has been put into practical use in various ways to increase the specific weight of the air-fuel mixture and increase its packing density by pressurizing the intake air supplied to the combustion chamber of the engine, thereby increasing the output of the engine. has been made into As means for pressurizing intake air, in addition to centrifugal and axial flow compressors, positive displacement compressors are also used. To drive such a compressor, a turbine driven by exhaust gas is used, or the output of the engine is used directly.

When a mechanical compressor such as a vane pump is used as a supercharger to compress intake air, the supercharger is constantly driven by the engine.
Depending on the load condition of the engine, supercharging may not be necessary, but rather increases the load on the engine unnecessarily, resulting in poor fuel efficiency. Therefore, by installing an electromagnetic clutch on the input shaft of the turbocharger and shutting off the clutch as necessary, or by connecting the front and rear of the turbocharger with a bypass passage and opening and closing the passage with a control valve, overheating can be prevented. Japanese Patent Application Laid-Open No. 56 (1973) proposed that when no air supply is required, the intake air is recirculated from downstream of the supercharger to upstream of the supercharger, reducing the torque required to drive the supercharger as needed, and reducing unnecessary burden on the engine. It is publicly known from the publication No.-16817.

On the other hand, in the above-mentioned positive displacement compressors such as vane pumps and Roots pumps, multiple working chambers partitioned by vanes etc. pump working fluid while gradually decreasing the volume from the suction port to the discharge port. Since it is compressed and delivered to the discharge port, it generates pulsating waves whose frequency depends on the rotational speed of the rotor etc. and the number of vanes etc. Since such pulsating waves cause noise, it is desirable to attenuate them as much as possible.

As a means to attenuate such pulsating waves,
It is known to provide a silencing chamber in the middle of a discharge passage, and the greater the change in passage cross-sectional area from the discharge passage to the silencing chamber, the more effective it is.

In addition, in the passage from the discharge port to the silencing chamber, pulsating waves exist without being significantly attenuated, so radiated sound from the passage becomes a problem.
It is desirable to make such passages as short as possible and to increase the rigidity of their walls.

In order to solve these problems, conventional supercharging pressure control methods include providing a silencing chamber on the downstream side of the turbocharger and connecting the downstream side of the silencing chamber and the upstream side of the turbocharger with a bypass passage. structure is proposed.

However, in such a conventional pressurization control structure, the bypass passage with the control valve and the silencing chamber are individually attached to the supercharger, which requires a considerable amount of space and takes up a lot of space in the limited engine room. The internal space could not be used effectively, and if the silencing chamber was provided at a distance from the supercharger, the sound radiated from the supercharger would become extremely loud.

<Problems to be solved by the invention> In view of these problems of the conventional technology, the main purpose of the invention is to avoid as much as possible the transmission of the discharge pulsation of the supercharger to the outside via the bypass passage. Another object of the present invention is to provide a supercharging pressure control structure including a noise reduction chamber and a bypass passage, which has an extremely compact configuration.

<Means for solving the problem> According to the present invention, this purpose is to bypass the turbocharger and transfer at least a part of the pressurized intake air from the discharge side of the turbocharger to the suction side of the turbocharger. In an internal combustion engine with a supercharger, the engine is equipped with a bypass passage for recirculating the air to In the intake passage structure, the silencing chamber is formed integrally with the bypass passage on an outer peripheral portion of the bypass passage, and the noise reduction chamber is formed integrally with the bypass passage on an upstream side of the bypass control valve of the supercharger. A suction passage communicating with the suction port is provided, an opening communicating with the silencing chamber is provided downstream of the bypass control valve in the bypass passage, and an opening communicating with the silencing chamber communicates with a discharge port of the supercharger. This is achieved by providing an intake passage structure in a supercharged internal combustion engine that is characterized by being provided with a discharge passage.

<Function> In this way, by providing a bypass passage in communication with the suction side and the discharge side of the supercharger, and by integrally attaching a silencing chamber to the bypass passage,
The discharge pulsation of the turbocharger is attenuated by the silencing chamber, and the noise caused by the pulsating sound discharged to the outside via the air cleaner is significantly suppressed. Moreover, by integrating the bypass passage and the silencing chamber, the space required is significantly reduced. Furthermore, the rigidity of the wall surface of the discharge passage can be increased, and since a bypass passage with an integrated sound-deadening chamber is directly connected to the turbocharger, the noise radiated from the turbocharger can be reduced. I can do it.

<Embodiments> The present invention will now be described in detail with reference to specific embodiments with reference to the accompanying drawings.

FIG. 1 shows a system diagram of the entire intake path of a supercharged internal combustion engine equipped with a supercharging pressure control structure based on the present invention.

A filter element 2 of a filter paper type is installed inside an air cleaner case 1 having an opening open to the atmosphere to purify the air taken in. The air purified here is guided to a bypass chamber 4 through a conduit 3 and sucked into a supercharger 5 such as a vane pump or a roots pump.

The supercharger 5 compresses intake air introduced from an intake port by a rotor, vanes, etc. driven by the crankshaft of the engine via a pulley and a belt, and sends it to a discharge port.

Intake air pressurized by the supercharger 5 is guided from the discharge port to the bypass chamber 4, and the bypass chamber 4 absorbs discharge pulsations.
The intake air discharged from the bypass chamber 4 passes through a discharge pipe 7 connected to the downstream side of the bypass chamber 4 and enters the surge tank 8 from the upper part of the surge tank 8 disposed downstream of the discharge pipe 7. Although sent,
The discharge pulsation that still remains at this time is further attenuated by the volume of the surge tank 8, together with the suction pulsation generated at the intake port of the carburetor 9 due to the reciprocating movement of the piston 10 in the engine 13. In addition, the surge tank 8 has a relief valve 11 as a pressure regulating valve.
is provided, and the pressure in the surge tank 8 closes the relief valve body 11a using a coil spring 1.
When the pressure rises above a set value due to the spring force of 1b, excess air is released to prevent the supercharging pressure from rising excessively.

The intake and outlet ports of the above-mentioned surge tank 8 are arranged with height differences in the vertical direction, and the intake air sent from above is connected almost directly to the intake port of the carburetor at the bottom of the tank. Air is supplied to the suction passage 9a of the carburetor 9 from the suction outlet. Because the intake and inlet ports are arranged with a difference in height between the top and bottom, even when blowback occurs from the carburetor, the fuel stays below the surge tank 8 due to gravity, and the fuel is not delivered to the supercharger. can be avoided.

The intake air pressure-fed to the carburetor 9 in this way is
Finally, it is mixed with fuel in the carburetor 9 and the intake manifold 12, and is sent into the combustion chamber 15 in the upper part of the cylinder according to the movement of the intake valve 14 of the engine 13. Naturally, the gases of the combustion chamber are exhausted to the exhaust manifold 17 by the movement of the exhaust valve 16 and the piston 10.

In the intake path of such a supercharged internal combustion engine, the bypass chamber 4 is arranged as shown in FIGS.
As clearly shown in the figure, a control valve 21 driven by an actuator 20 that responds to the supercharging pressure obtained through a supercharging pressure derivation port 8a and a derivation pipe 8b provided in the surge tank 8 is connected to a bypass passage. 22 is rotatably supported via a valve shaft 23. The control valve 21 is normally closed, but opens when the boost pressure exceeds a predetermined value, and serves to prevent the boost pressure from becoming excessive. An inlet 24 through which intake air is introduced and an outlet 25 through which pressurized intake air is fed are opened on opposite sides of the side walls of the bypass passage 22 on the upstream and downstream sides of the control valve 21, respectively. ing. The suction port 26 of the supercharger 5 is connected to the suction port 24.
The suction passage 27 connected to the suction port 26 has a flange surface 28 having the same diameter as the end surface of the suction port 26,
It is provided in a protruding manner on the side wall of the bypass passage 22.
Further, a discharge passage 30 connected to the discharge port 29 of the supercharger 5 is aligned with the flange face 28 of the suction passage 27 with a flange face 31 having the same diameter as the end face of the discharge port 29 as an end face, It is provided to protrude from the side wall of the bypass passage 22. The discharge passage 3
A silencing chamber 32 is integrally defined on the outer periphery of the bypass passage 22 and communicates with the discharge port 25 and has a passage cross-sectional area rapidly enlarged compared to the discharge passage 30.

As clearly shown in FIGS. 1 to 3, the bypass chamber 4 and the supercharger 5 are connected by connecting the flange surface 28 of the suction passage 27 and the flange surface 31 of the discharge passage 30. The suction port 2
6 and the flange surface of the discharge port 29, respectively, and the flange surfaces 38, 31
The boss part 33 of the bypass chamber 4 and the boss part of the supercharger 5 are opposed to each other, and the internal thread is screwed into the boss part. This is done by screwing and tightening bolts. Furthermore, the connection between the bypass chamber 4, the conduit 3, and the discharge pipe 7 is as follows:
As clearly shown in FIGS. 1 to 3, the upstream flange surface 35 and downstream flange surface 36 of the bypass chamber 4 are connected to the flange surface of the conduit 3 and the flange surface of the discharge pipe 7. This is accomplished by joining the flange surfaces 35 and 36, respectively, and tightening the bolts by screwing them into internal threads screwed into the flange surfaces 35 and 36.

The intake air introduced into the conduit 3 is guided to the upstream side of the bypass passage 22, and is sucked into the intake port 26 of the supercharger 5 via the intake passage 27. The intake air pressurized by the supercharger 5 generates pulsating noise on the discharge side, but by rapidly expanding the pressurized intake air in the muffling chamber 32, this discharge pulsation is absorbed and the pulsating noise is eliminated. is being reduced.

In the case of a supercharger that is operated by the driving force of the engine's crankshaft, it constantly compresses the intake air, and even when the throttle valve 18 is closed at low loads, supercharging is performed, and the pump There is a disadvantage that the load worsens fuel efficiency. Therefore, a bypass chamber 4 having a control valve 21 driven by an actuator 20 responsive to supercharging pressure is provided to bypass the supercharger 5.
The downstream side of the supercharger 5 and the upstream side of the supercharger 5 are connected. In this way, when the engine is under low load with the throttle valve 18 generally closed,
The control valve 21 is opened and the bypass chamber 4 is opened.
The discharge port 29 and suction port 2 of the supercharger 5
6, the supercharging pressure is returned upstream from the supercharger 5, thereby reducing the pump load at low load times.

Note that the means for controlling the opening and closing of the control valve 21 is not limited to the configuration in which control is performed via the actuator 20 that responds to boost pressure as shown in the embodiment described above, but may include the throttle valve 18 and a mechanical device, although not shown. The throttle valve 18 and the control valve 21 are interlocked and connected.
It is also possible to adopt a configuration in which the two perform operations opposite to each other.

<Effects of the invention> As described above, according to the invention, the turbocharger can be controlled simply by integrally attaching the noise reduction chamber to the boost pressure control bypass passage which has a control valve that operates according to the engine load condition. It is possible to effectively avoid a situation where the discharge pulsation is radiated to the outside through the bypass passage and the air cleaner and causes noise.

Moreover, by integrating the bypass passage and the silencing chamber, both can be made extremely compact, the required space can be significantly reduced, and the space in the engine room can be used effectively. Moreover, when the bypass chamber is directly connected to the supercharger, the distance between the supercharger and the silencing chamber is shortened, and the sound radiated from the supercharger is reduced.
Furthermore, in the case where the silencing chamber is defined around the circumference of the bypass passage, the ambient temperature around the control valve is maintained at a substantially uniform temperature, so deformation or distortion of the bypass passage is less likely to occur, and the return of the control valve is prevented. The occurrence of malfunctions such as defects is eliminated.

[Brief explanation of the drawing]

FIG. 1 is an intake path system diagram of an engine equipped with a boost pressure control structure based on the present invention. FIG. 2 is a perspective view of a bypass chamber used in the boost pressure control structure of the present invention. 3 is a horizontal cross-sectional view of the bypass chamber of FIG. 2; FIG. 1... Air cleaner case, 2... Filter element, 3... Conduit, 4... Bypass chamber, 5... Supercharger, 7... Discharge pipe, 8... Surge tank, 8a... Supercharging pressure lead-out Port, 8b... Outlet pipe, 9... Carburizer, 10... Piston, 11...
...Relief valve, 12...Intake manifold, 13
... Engine, 14 ... Intake valve, 15 ... Combustion chamber, 16 ... Exhaust valve, 17 ... Exhaust manifold, 18 ... Throttle valve, 20 ... Actuator, 21 ... Control valve, 22 ... Bypass passage ,
23...Valve shaft, 24...Intake port, 25...Discharge port, 26...Suction port, 27...Suction passage, 2
8...Flange surface, 29...Discharge port, 30...
...discharge passage, 31...flange surface, 32...muffling chamber.

Claims (1)

[Claims for Utility Model Registration] (1) A bypass passage that bypasses the turbocharger and circulates at least a portion of the pressurized intake air from the discharge side of the turbocharger to the suction side of the turbocharger, and the inside of the passage. An intake passage structure for an internal combustion engine with a supercharger, comprising a bypass control valve provided on the discharge side of the supercharger, and a silencing chamber provided on the discharge side of the supercharger to absorb discharge pulsation, the silencing chamber comprising: A suction passage is formed integrally with the bypass passage on an outer peripheral portion of the bypass passage, and is provided on the upstream side of the bypass control valve in the bypass passage and communicates with the suction port of the supercharger, A supercharger characterized in that an opening communicating with the silencing chamber is provided on the downstream side of the bypass control valve in the passage, and a discharge passage communicating with the discharge port of the supercharger is provided in the silencing chamber. Intake passage structure for internal combustion engines. (2) The utility model registration claim 1 is characterized in that the suction passage is directly connected to the suction port of the supercharger, and the discharge passage is directly connected to the discharge port of the supercharger. Intake passage structure in a supercharged internal combustion engine.