JPH10122187A - Impeller structure of compressor in supercharger for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impeller structure of a compressor in a supercharger for an internal combustion engine capable of reducing the supercharger flow noise such as the discharge sound of a compressor outlet. SOLUTION: An impeller main body 14A is integrally molded with multiple high long blades 16 and low half blades 17 in turn in the peripheral direction from the downstream end of the impeller main body 14A as impeller blades, multiple resin straightening vanes 18 having an impeller blade shape and extended to the positions facing the upstream ends of the half blades 17 from the upstream end of an impeller 14 are fitted to a rotary shaft 13 corresponding to the half blades 17. The difference in height between the long blades 16 and the half blades 17 is eliminated, the pressure pulsation (amplitude of pressure wave) is reduced, and the turbo-charger flow noise such as the discharge sound of a compressor outlet is reduced. The height of at least one long blade 16 among multiple long blades 16 from the downstream end of the impeller 14 is gradually reduced toward the periphery section from the center section, the frequency of the pressure pulsation is changed, and the turbo-charger flow noise is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor in a supercharger attached to an internal combustion engine for a motor vehicle, and more particularly to a structure of an impeller.

[0002]

2. Description of the Related Art Conventionally, an internal combustion engine is generally provided with a supercharger (turbocharger), and the intake air supplied to the engine is supercharged to improve the output generated by the engine and the fuel efficiency. It has been done. FIG. 15 shows a configuration of an internal combustion engine 2 provided with a turbocharger 1. The exhaust gas turbine 4 is rotationally driven by the energy of the exhaust gas discharged through the exhaust gas passage 3, whereby the intake passage 5 is rotated.
The compressor 6 is connected to the exhaust turbine 4 and is rotatably driven to supercharge the intake air (see Japanese Patent Application No. 7-120025).

[0003] The compressor 6 comprises an impeller 4A and a compressor housing 4B connected to a rotating shaft 7 common to the exhaust turbine 4, and the impeller 4A.
With the rotation of, the speed energy is given to the intake air, and this speed energy is converted into pressure energy by the diffuser provided in the compressor housing 4B.

[0004]

Heretofore, the main body of the impeller is conventionally well known to be made of aluminum. In recent years, however, in order to improve the transient response of the turbocharger, the moment of inertia of the rotor of the turbocharger has been improved. Resin has been proposed which is advantageous for reducing the amount of nitrogen (see Nissan Technical Report No. 36 (issued in October 1995) and the Nissan Gloria catalog (1995-1996 edition)).

When the impeller body is formed of aluminum, a lost wax method is used. According to the lost wax method, there are few restrictions on the shape of the impeller blades, and it is possible to form a complicated blade shape. However, when the impeller body is molded from resin, an injection molding method using a mold is used. In this method, there are many restrictions on the impeller blade shape,
It is impossible to form a complicated wing shape.

[0006] In a resin-made impeller body that has been conventionally proposed against such a background, when a long blade and a half blade are alternately provided as impeller blades, the height of the half blade is increased. Difficult to raise. That is, in the impeller body made of resin, the height of the half blade cannot be increased due to the die cutting with the injection molding die.

For this reason, the height difference between the long blade and the half blade, that is, the step is increased, the pressure pulsation (the amplitude of the pressure wave) is increased, and the airflow noise of the turbocharger such as the discharge sound at the compressor outlet is increased. There is a problem to do. It has been found through experiments by the present inventors that there is a correlation between the pressure pulsation and the discharge sound.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to reduce the airflow noise of a supercharger such as a discharge noise at a compressor outlet by improving a blade shape of an impeller of a compressor. It is an object of the present invention to provide a compressor impeller structure in a supercharger capable of performing the following.

[0009]

According to a first aspect of the present invention, there is provided an exhaust turbine provided in an exhaust passage of an internal combustion engine and a compressor connected to the exhaust turbine and provided in an intake passage. In the supercharger, the main body of the impeller coupled to the rotating shaft of the compressor, as the impeller blades, a long blade having a high height from a downstream end of the impeller and a low half blade are alternately arranged in a circumferential direction. A plurality of impeller wing-shaped rectifying plates provided on the rotary shaft corresponding to each half blade and extending from an upstream end of the impeller to a position facing the upstream end of each half blade. In addition, a plurality of straightening plates constituting impeller blades located at positions between the long blades are attached together with the half blades.

Here, for example, when the impeller body is formed of resin, if the impeller blades have a configuration in which long blades and half blades are alternately provided, it is difficult to increase the height of the half blades. The difference in height between the blade and the half blade, that is, the step, becomes large, and the pressure pulsation (the amplitude of the pressure wave) becomes large, causing a turbocharger airflow noise such as a discharge noise at the compressor outlet.

According to the first aspect of the present invention, an impeller wing shape is provided on the rotating shaft corresponding to each half blade and extends from an upstream end of the impeller to a position facing the upstream end of each half blade. As a result of mounting a plurality of straightening plates, each straightening plate constitutes an impeller blade located at a position between the long blades, and the height difference between the long blades and the half blades can be eliminated.

That is, the straightening plate makes the half blade, which is lower in height than the long blade, have the same height as the long blade, and is made longer. The invention according to claim 2 is characterized in that the impeller main body and the rectifying plate having the long blade and the half blade are each formed of resin.

The invention according to claim 2 is advantageous for reducing the moment of inertia of the turbocharger rotating body for the purpose of improving the transient response of the supercharger for an internal combustion engine. The invention according to claim 3 is characterized in that the impeller body is
It is characterized by being molded by injection molding using a resin mold.

According to the third aspect of the invention, the impeller body is easily formed. The invention according to claim 4 is characterized in that the rectifying plate is provided on a boss member coupled to a rotating shaft of the compressor together with the impeller body. In the invention according to claim 4,
A current plate is easily provided on the impeller body.

According to a fifth aspect of the present invention, there is provided a supercharger including an exhaust turbine provided in an exhaust passage of an internal combustion engine and a compressor axially connected to the exhaust turbine and provided in an intake passage. On the main body of the impeller coupled to the rotating shaft of the compressor, as an impeller blade,
A long blade high from the downstream end of the impeller,
A plurality of lower half blades are alternately formed integrally with each other in the circumferential direction, and the height of at least one of the plurality of long blades from the downstream end of the impeller is set to be equal to the height from the center. It is characterized in that it is formed gradually lower as it goes to the part.

According to the fifth aspect of the present invention, if the height of the long blade from the downstream end of the impeller is gradually reduced from the center to the periphery, the airflow from the inlet of the compressor to the impeller blades is increased. Hits with a time difference between the center and the periphery of the long blade. In this manner, the frequency of the pressure pulsation can be changed by the airflow from the inlet of the compressor toward the impeller blades having a time difference between the center and the periphery of the long blade.

Therefore, by selecting the number of long blades which are inclined as described above, it is possible to control the frequency of the pressure pulsation and tune the turbocharger airflow sound such as the discharge sound at the compressor outlet. The invention according to claim 6 is such that the upstream end of the long blade is formed to be inclined, and the height from the downstream end of the impeller body is gradually reduced from the center to the periphery. It is characterized by having done.

In the sixth aspect of the present invention, when the long blade is formed, the long blade can be easily formed into a desired shape. The invention according to claim 7 is characterized in that the impeller main body having the long blade and the half blade is formed of resin.

The invention according to claim 7 is advantageous in reducing the moment of inertia of the rotary body of the turbocharger for the purpose of improving the transient response of the supercharger for the internal combustion engine. In the invention according to claim 8, the impeller main body includes:
It is characterized by being molded by injection molding using a resin mold.

In the invention according to claim 8, the impeller body is easily formed.

[0021]

According to the first aspect of the present invention, the pressure pulsation (the amplitude of the pressure wave) in the impeller of the compressor can be reduced, and the airflow noise of the turbocharger such as the discharge sound at the compressor outlet can be effectively reduced. It can be aimed at. .

According to the second aspect of the invention, the transient response of the supercharger for the internal combustion engine can be improved. Claim 3
According to the invention according to the above, the impeller body can be easily formed,
Excellent manufacturability. According to the fourth aspect of the present invention, the current plate can be easily provided on the impeller body, and the manufacturability is excellent.

According to the fifth aspect of the present invention, by controlling the frequency of the pressure pulsation and tuning the discharge sound of the compressor outlet and the like, it is possible to effectively reduce the airflow noise of the turbocharger. Claim 6
According to the invention, the long blade can be easily formed into a desired shape.

According to the present invention, the transient response of the supercharger for an internal combustion engine can be improved. Claim 8
According to the invention according to the above, the impeller body can be easily formed,
Excellent manufacturability.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the attached drawings. FIG. 1 shows the structure of a turbocharger. A turbocharger 10 is composed of an exhaust turbine 11 provided in an exhaust passage and a compressor 12 connected to the exhaust turbine 11 and provided in an intake passage. I have.

The compressor 12 is provided with the exhaust turbine 1
The compressor housing 15 includes an impeller 14 and a compressor housing 15 which are coupled to a common rotation shaft 13 with the compressor housing 1.
It is composed of a diffuser 15B and a scroll 15C. 2 and 3 show the configuration of the impeller 14, and the main body 14A of the impeller 14 is formed by injection molding using a resin mold as described in the section of the prior art.

Here, the impeller main body 14A is provided with a plurality of long blades 16 having a height from the downstream end of the impeller main body 14A and a plurality of half blades 17 having a low height alternately in the circumferential direction. (6 sheets in each case). The rotating shaft 13 is provided corresponding to each half blade 17, and the impeller 14
A plurality of (six in the present embodiment) resin rectifying plates 18 having an impeller blade shape extending from the upstream end to the position facing the upstream end of each half blade 17 are attached.

The current plate 18 is provided with each half blade 17.
Together, they constitute impeller blades located between the long blades 16. The current plate 18 has a configuration as shown in FIGS. 4 to 7, and the impeller body 1 is attached to the rotating shaft 13.
It is connected to the boss member 19 which is connected together with 4A. In this case, the grooves 2 are provided at predetermined intervals on the peripheral portion of the boss member 19.
The mounting piece 18A formed on the inner end of the current plate 18 is fitted and fixedly mounted in each groove 20.

Boss member 19 with current plate 18 attached
Is inserted into the upstream end portion of the rotating shaft 13, and is tightened together with the impeller main body 14 </ b> A by tightening the fastener 20.
3 According to the impeller structure of the compressor 12 having such a configuration, the following operation and effect can be obtained.

That is, as described in the section of the prior art, when the impeller body is formed of resin, when the long blades and the half blades are alternately provided as the impeller blades, the height of the half blade is reduced. Difficult to raise, the difference in height between the long blade and half blade,
That is, the step becomes large and the pressure pulsation (the amplitude of the pressure wave) becomes large, which causes a turbocharger airflow sound such as a discharge sound at the compressor outlet.

As described above, a plurality of impeller blade-shaped blades are provided on the rotating shaft 13 so as to correspond to the half blades 17 and extend from the upstream end of the impeller 14 to a position facing the upstream end of each half blade 17. As a result of attaching the resin rectifying plates 18 of the above, each rectifying plate 18 constitutes an impeller blade positioned between the long blades 16,
The height difference between the long blade 16 and the half blade 17 can be eliminated.

That is, the half blade 17 is made longer by the current plate 18. As a result, the pressure pulsation (the amplitude of the pressure wave) can be reduced, and the airflow noise of the turbocharger such as the discharge sound at the compressor outlet can be reduced. Next, another embodiment of the present invention will be described with reference to FIGS.

In this embodiment, the main body 21A of the impeller 21 made of resin is provided with impellers 2 as impeller blades.
1 is similar to the previous embodiment in that a plurality of long blades 22 and a low half blade 23 having a height from the downstream end are alternately and integrally formed in the circumferential direction. The feature of this embodiment is that the height of at least one of the long blades 22 (all six blades in this embodiment) from the downstream end of the impeller 21 goes from the center to the periphery. In that it is gradually lowered.

Specifically, the upstream end of the long blade 22 is formed by being inclined, and the height from the downstream end of the impeller 21 is gradually reduced from the center to the periphery. I have to. Thus, the long blade 22
When the height from the downstream end of the impeller 21 is gradually reduced from the center to the periphery, the airflow from the inlet of the compressor toward the impeller blades becomes longer.
Hit each with a time difference from the center to the periphery.

For example, there is a time difference between when the airflow hits the central portion of the long blade 22 and when it hits the peripheral portion, when the airflow hits the central portion of the long blade 22 is earlier than when it hits the peripheral portion. As described above, the frequency of the pressure pulsation can be changed by the airflow from the compressor inlet to the impeller blades being applied with a time difference from the center to the periphery of the long blade 22.

Therefore, by selecting the number of the long blades 22 which are inclined as described above, the frequency of the pressure pulsation is controlled, and the turbocharger airflow sound such as the discharge sound of the compressor outlet is tuned to obtain the turbocharger. Charger airflow noise can be reduced. This tuning will be described in accordance with the experimental examples of the present inventors.

FIG. 10 shows the pressure pulsation generated when the conventional impeller structure is adopted. The second, third, fourth and sixth-order pressure pulsations are large, and the turbocharger airflow noise such as the discharge noise at the compressor outlet is generated. large. 11 to 13 show pressure pulsations generated when the impeller structure of the present invention is adopted, and FIG. 11 shows a case where inclined portions are provided on two symmetrical long blades.

In this example, third and fourth order pressure pulsations are reduced. FIG. 12 shows a case where inclined portions are provided on three symmetrical long blades. In this example, the second and fourth order pressure pulsations are reduced. FIG. 13 shows a case where all six long blades are provided with inclined portions. In this example, the second, third and fourth order pressure pulsations are reduced.

As described above, it is apparent that the pressure pulsation is reduced when the long blade is provided with the inclined portion, and by selecting the number of the long blades to be inclined, the discharge sound at the compressor outlet and the like can be reduced. The tuning of the turbocharger airflow sound may be performed. As described above, the mechanism by which the pressure pulsation of a predetermined order is reduced when the long blade is provided with the inclined portion is as follows.

In the conventional impeller structure, the size of each long blade varies, and the magnitude of the pressure wave differs for each blade (see FIG. 14A). In such a state, a combined wave generated when the impeller rotates is a combination of all six pressure waves (see FIG. 14B). On the other hand, for example, when a symmetrical long blade is provided with an inclined portion, pressure waves of two long blades provided with the inclined portion become large (see FIG. 14C).

Since the composite wave generated when the impeller rotates is dominated by the large pressure wave, it becomes a composite of two pressure waves, and the pressure waves of the other long blades cancel each other (see FIG. 14D). ). As a result, as described with reference to FIG. 11, when the symmetrical two long blades are provided with the inclined portions, the third and fourth order pressure pulsations are reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a turbocharger showing one embodiment of the present invention.

FIG. 2 is a front view showing an impeller structure of the turbocharger according to the first embodiment;

FIG. 3 is a side view thereof.

FIG. 4 is a front view showing a structure of a current plate applied to the impeller of the above.

FIG. 5 is a side view thereof.

FIG. 6 is a longitudinal sectional view thereof.

FIG. 7 is a perspective view thereof.

FIG. 8 is a front view of an impeller showing another embodiment of the present invention.

FIG. 9 is a side view thereof.

FIG. 10 is a graph showing pressure pulsation generated when a conventional impeller structure is employed.

FIG. 11 is a graph showing pressure pulsation generated when the impeller structure of the present invention is employed.

FIG. 12 is a graph showing pressure pulsation generated when the impeller structure of the present invention is adopted.

FIG. 13 is a graph showing pressure pulsation generated when the impeller structure of the present invention is employed.

FIG. 14 is a diagram illustrating a mechanism that reduces pressure pulsation of a predetermined order when a long blade is provided with an inclined portion.

FIG. 15 is a diagram illustrating a configuration of an internal combustion engine including a turbocharger.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Turbocharger 11 Exhaust turbine 12 Compressor 13 Rotating shaft 14 Impeller 14A Impeller main body 16 Long blade 17 Half blade 18 Straightening plate 19 Boss member 21 Impeller 21A Impeller main body 22 Long blade 23 Half blade

Claims (8)

[Claims] 1. A supercharger comprising: an exhaust turbine provided in an exhaust passage of an internal combustion engine; and a compressor axially connected to the exhaust turbine and provided in an intake passage. On the main body of the impeller to be combined, as the impeller blades, a long blade having a high height from the downstream end of the impeller and a low half blade are alternately and integrally formed in the circumferential direction by a plurality of pieces. , Provided for each half blade,
An impeller wing-shaped straightening plate extending from an upstream end of the impeller to a position facing the upstream end of each half blade,
An impeller structure of a compressor in a supercharger for an internal combustion engine, wherein a plurality of straightening plates constituting an impeller blade located at a position between each long blade are mounted together with each half blade. 2. The compressor impeller structure for a supercharger for an internal combustion engine according to claim 1, wherein the impeller main body and the rectifying plate having the long blade and the half blade are each formed of a resin. 3. The impeller structure for a compressor in an internal combustion engine supercharger according to claim 2, wherein said impeller body is formed by injection molding using a resin mold. 4. The supercharger for an internal combustion engine according to claim 1, wherein the rectifying plate is provided on a boss member connected to a rotating shaft of the compressor together with the impeller body. Impeller structure of compressor in feeder. 5. A supercharger comprising: an exhaust turbine provided in an exhaust passage of an internal combustion engine; and a compressor connected to the exhaust turbine and provided in an intake passage. On the main body of the impeller to be combined, as the impeller blades, a long blade having a high height from the downstream end of the impeller and a low half blade are alternately and integrally formed in the circumferential direction by a plurality of pieces. A compressor in a supercharger for an internal combustion engine, wherein the height of at least one of the long blades from the downstream end of the impeller is gradually reduced from the center to the periphery. Impeller structure. 6. The method according to claim 6, wherein an upstream end of the long blade is formed to be inclined, and a height from a downstream end of the impeller body is gradually reduced from a center portion to a peripheral portion. The impeller structure of a compressor in a supercharger for an internal combustion engine according to claim 5, characterized in that: 7. The compressor impeller structure for a supercharger for an internal combustion engine according to claim 5, wherein the impeller body having the long blades and the half blades is formed of resin. 8. An impeller structure for a compressor in an internal combustion engine supercharger according to claim 5, wherein said impeller body is formed by injection molding using a resin mold.