JPS6176798A - Compressor - Google Patents

Abstract

PURPOSE:To improve the compressor efficiency by providing a valve mechanism openable/closable of the outlet of sub-scroll on the basis of suction air flow at the confluence of main and sub scrolls thereby making the scroll capacity variable with correspondence to suction air flow. CONSTITUTION:When suction air flow is higher than referential level, the negative pressure at the inlet of compressor is lower than referential level to turn on a negative pressure switch 57 thus to lead the pressure at the outlet 40 of main scroll 35 through three-way valve 55 into positive pressure chamber 53 of actuator 48. The diaphragm 49 of actuator 48 will move through said pressure to the atmospheric chamber 52 side against the energizing force of spring 54 thus to rotate a lever 46 and to rotate a valve body 43 provided at the confluence of main and sub scrolls 35, 36 from position B to A. Consequently, the outlet 41 of sub-scroll 36 is opened to flow suction air through main and sub scrolls 35, 36 thus to increase the scroll capacity when compared with the case employing only main scroll 35 resulting in high compressor efficiency even under high flow zone.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a compressor, particularly a centrifugal or mixed flow type compressor used in a supercharger, a gas turbine, or the like.

(Prior art) In general, a supercharger uses engine power or exhaust gas to drive a compressor wheel and supply compressed air as energy (supercharging) to increase supercharging pressure, improve output, and fuel efficiency. The aim is to improve the ratio of Such a compressor is required to have an appropriate discharge pressure over a wide range of intake air flow rates in order to improve output, fuel efficiency, etc. over a wide range of engine speeds.

Therefore, in a compressor used in a conventional turbocharger, holes are formed in a part of the parallel wall of the compressor having a so-called parallel wall diffuser, as shown in Japanese Patent Laid-Open No. 57-13232, for example. By opening and closing this hole based on the engine speed, boost pressure is obtained over a wide range of intake air flow rates.

That is, in FIG. 9, the compressor housing 1 defines a parallel wall diffuser 3 between it and the bearing housing 2, and also defines a scroll 4 on the outer periphery of the parallel wall diffuser 3. A plurality of openings 5 are formed in the portion of the parallel wall diffuser 3. The opening 5 is opened and closed by a partition plate 7 in which a plurality of openings 6 that can be aligned with the opening 5 are formed.

A compressor wheel 8 is housed within the compressor housing 1, and the compressor wheel 8 is connected to a turbine wheel 10 by a shaft 9 rotatably supported by the hair ring housing 2. The turbine wheel 1o is housed within a turbine housing 11, and is rotated by the energy of exhaust gas from the engine. When the turbine wheel 10 rotates, the compressor wheel /L/
After 8 k cycles, the compressor wheel 8 accelerates the air introduced through the inlet 12 of the compressor housing 1 to a very high degree of turbulence due to centrifugal force.

Accelerated air is passed through parallel wall diffuser 3 and scroll 4
and is sent through outlet 13 to the combustion chamber of the engine.

At this time, the accelerated air is dissipated in the parallel wall diffuser 3 and scroll 4, and its velocity energy is converted into pressure energy and supplied to the combustion chamber of the engine as high-pressure air. When the engine speed is low, the opening 5 is closed with a partition plate 7 to prevent outside air from flowing in and to maintain an appropriate boost pressure.

Also, when the engine speed is high, the openings 5 and 6
The compressor flow rate is increased by aligning the outside air through the opening 5.6 with the negative pressure of the parallel wall diffuser 3 (the air flow in the diffuser 3 is close to the speed of sound). Therefore, the compressor flow rate can be adjusted over a wide range of engine speeds from low speeds to high speeds, and the boost pressure can be adjusted.

(Problem to be Solved by the Invention) However, in such conventional turbochargers, negative pressure caused by high-speed airflow is used in the diffuser to obtain a predetermined boost pressure over a wide range of engine speeds. Since the compressor was configured to let outside air flow in through the diffuser, the mixing loss between intake air and outside air at the diffuser and the pressure recovery rate of the diffuser deteriorated, resulting in a significant decrease in compressor efficiency in a large flow rate range. As a result, there has been a problem in that sufficient boost pressure cannot be obtained in the large flow region, and engine output and fuel efficiency cannot be sufficiently improved.

(Objective of the Invention) Therefore, the present invention provides a main scroll and a sub-scroll that are connected to each other through a communication hole on the outer periphery of the diffuser, and also provides a valve mechanism that opens and closes the outlet of the sub-scroll based on the intake air flow rate. The purpose is to maintain high compressor efficiency over a wide flow range and improve engine output and fuel efficiency.

(Means for Solving the Problems) The compressor of the present invention includes a diffuser formed in the compressor housing along the circumference near the tip of the compressor wheel, a main scroll communicating with the diffuser on the outer periphery of the diffuser, and a main scroll connected to the diffuser. A sub-scroll that joins the main scroll at the exit and is communicated with the main scroll through a communication hole is formed separately, and the outlet of the sub-scroll can be opened and closed based on the flow rate of intake air at the confluence of the main scroll and the sub-scroll. It is equipped with a valve mechanism.

(Operation) When the compressor wheel is rotated, the intake air is accelerated and delivered to the main scroll through the diffuser. At this time, by opening and closing the outlet of the sub-scroll using the valve mechanism based on the amount of intake air, the scroll capacity can be made variable in accordance with the amount of intake air, and compressor efficiency can be improved.

(Example) Embodiments of the present invention will be described below based on the drawings.

1 to 8 are diagrams showing an embodiment in which a compressor according to the present invention is applied to a turbocharger.

First, to explain the configuration, in FIG.
3 with a lock nut 24. A turbine wheel (not shown) is fixed to the other end of the shaft 23, and the turbine wheel rotates by receiving the energy of the exhaust gas. A compressor housing 25 is attached to the bearing housing 22, and the compressor housing 25 is composed of a shroud housing 26 and a scroll housing 27.

The scroll housing 27 is the hair ring housing 22
bolt 3 through retainer 28 and gasket 29.
The mounting angle of the scroll housing 27 can be adjusted by aligning the retainer 28 eight times. A shroud housing 26 is fixed to the scroll housing 27 with bolts 31, and a ring 32 is interposed between the scroll housing 27 and the shroud housing 26. The shroud housing 26 surrounds the compressor wheel 21 and defines a so-called parallel wall type diffuser 33 along the circumference near the tip of the compressor wheel 21 between the shroud housing 26 and the bearing housing 22.
Further, an inlet 34 is formed for introducing intake air into the compressor wheel 21.

The scroll housing 27 is the shroud housing 26
Along with this, there is a small flow rate on the outer periphery of the diffuser 33.

The main scroll 35 and the sub scroll 36 are separated by an outer partition wall 37 and an inner partition wall 38, and are separated by a partition wall 37 and a partition wall 38. Communication hole 3 formed between
9 communicates with each other. The partition wall 37 is formed in the scroll housing 27 so as to protrude in the inner circumferential direction, and its inner circumferential tip is closer to the main scroll 3 than the sub scroll 36 side.
It is inclined in the outer circumferential direction toward the 5th side. In addition, partition wall 3
8 is formed on the shroud housing 26 so as to protrude briefly in the outer circumferential direction, and its outer circumferential tip is connected to the sub scroll 36.
It is inclined in the outer circumferential direction toward the shroud scroll 35 side. Therefore, the communication hole 39 is formed in an annular shape near the main housing 26 (see FIG. 2), and is inclined in the outer circumferential direction from the sub scroll 36 side toward the main scroll 35 side.

As shown in FIGS. 2 to 4, the scroll housing 27 has a tube body 42 fixed to the outlet 40 and 41 ends of the main scroll 35 and the sub scroll 36.
Inside, a tongue-shaped valve body 43 is rotatably provided via a shaft 44. The valve body 43 is located on the extended surface of the partition wall 37 and is fixed to the shaft 44 with a screw 45. The valve body 43 is rotatable by a lever 46 connected to the shaft 44, and as shown in FIG. 42 and a position B where it is in close contact with the inner wall of the sub scroll 36 and closes the outlet 4 of the sub scroll 36.

Further, a rubber seal member 47 is fixed to the tip of the partition wall 37 and the periphery of the valve body 43, thereby improving the adhesion between the partition wall 37 and the valve body 43 and between the valve body 43 and the inner wall of the tube body 42. . Further, the sealing member 47 attached to the peripheral edge of the valve body 43 is formed to have a thinner tip, so that its close contact with the inner wall of the tube body 42 is further improved.

On the other hand, the lever 46 is connected to a rod 50 attached to a diaphragm 49 of an actuator 48, as shown in FIG.
It is divided into. A spring 54 that biases the diaphragm 49 toward the positive pressure chamber 53 is compressed in the atmospheric chamber 52, and positive pressure near the outlet 40 of the main scroll 35 is supplied to the positive pressure chamber 53 via a three-way solenoid valve 55. It has been introduced. When the field coil 56 of the three-way solenoid valve 55 is energized, the positive pressure chamber 53 and the main scroll 35 are connected to each other, and the field coil 56
When the energization is stopped, the positive pressure chamber 53 is communicated with the atmosphere. The field coil 56 is connected to a battery 58 via a negative pressure switch 57, and the negative pressure switch 57 is turned ON and OFF based on the negative pressure at the inlet 34 of the compressor. That is, in the negative pressure switch 57, the inside of the case 59 is divided into an atmospheric chamber 61 and a negative pressure chamber 62 by a diaphragm 60, and the negative pressure from the compressor inlet 34 is introduced into the negative pressure chamber 62, and the diaphragm 60 is connected to the atmospheric chamber 61 side. A spring 63 is provided to compress the spring 63. A contact piece 64 is connected to the diaphragm 60 via the rod 50, and the contact piece 64 turns on and off between contacts 65 and 66. Therefore, the negative pressure switch 57 sets the predetermined reference population negative pressure 2 in the negative pressure chamber 62.
When a negative pressure of 3 or more is introduced, it is turned on and the field coil 56 is energized, and the three-way solenoid valve 55 is activated by the actuator 48.
The positive pressure of the main scroll 35 is introduced into the positive pressure chamber 53 of the main scroll 35 . As a result, the actuator 48 moves the lever 46 in the direction of the arrow in FIG. 5 via the rod 50, rotates the valve body 43, and opens the outlet 41 of the sub scroll 36. The predetermined reference negative pressure Pn is determined by the predetermined intake air flow rate Qa (main scroll 35 Compressor artificial negative pressure P when the intake air flow rate is the limit at which high compressor efficiency can be maintained by
n. Therefore, the actuator 48
, the three-way solenoid valve 55 and the negative pressure switch 57 rotate the valve body 43 based on the intake air flow rate to close the sub scroll 36.
The valve body 43, shaft 44, lever 46, rod 50, actuator 48
, the three-way solenoid valve 55, and the negative pressure switch 57 constitute a valve mechanism 67 that can open and close the outlet 41 of the sub scroll 36 based on the flow rate of intake air.

Next, the action will be explained.

First, when the intake air flow rate is low than the reference flow rate Qa, the outlet 41 of the sub scroll 36 is closed by the valve body 43, and only the main scroll 35 is used.

That is, when the intake air flow rate is lower than the reference flow rate Qa, as shown in FIG. 6, the compressor artificial negative pressure is higher than the reference negative pressure Pn, and the negative pressure switch 5
7 is OFF. Therefore, the three-way solenoid valve 55
communicates the positive pressure chamber 53 of the actuator 48 with the atmosphere, and the actuator 48 presses the valve body 43 against the inner wall of the tube body 42 on the sub scroll 36 side to open the outlet 4 of the sub scroll 36.
1 is closed. Since the outlet 41 of the sub scroll 36 is closed, the intake air accelerated by the compressor/subwheel 21 flows from the diffuser 33 only through the main scroll 35 and is supplied to the combustion chamber of the engine. Therefore, the speed of the air accelerated by the compressor wheel 21 is relaxed in the diffuser 33 and the main scroll 35, and the velocity energy is converted into pressure energy to increase the pressure of the intake air. Since the main scroll 35 is designed for a small flow rate, the pressure of this intake air can be maintained at a sufficiently high compressor efficiency even in a low flow rate range, as shown by the solid line in Figure 7, allowing for moderate supercharging. You can get pressure. At this time, the communication hole 39
is inclined toward the outer circumference from the sub-scroll 36 side to the main scroll 35 side near the shroud housing 26, which prevents the air rotating the main scroll 35 from flowing into the sub-scroll 36 due to centrifugal force. This makes it possible to further improve compressor efficiency at low flow rates. Further, since the valve body 43 has a cantilevered valve shape with its rotating end at the tip of the partition wall 37, the passage area through which air flows is reduced from the main scroll 35 to the pipe body 4.
2, it is possible to suppress the spreading loss to the air flow to a small value. Furthermore, the sealing member 47 is attached to the tip of the partition wall 37 and the periphery of the valve body 43, and the sealing member 47 on the periphery of the valve body 43 is made thinner at the tip. 43 and the partition wall 37 can be improved, and only the main scroll 35 can be used without being affected by the sub scroll 36. therefore,
Compressor efficiency at low flow rates can be further improved, and appropriate supercharging pressure can be obtained.

Next, when the intake air flow rate is large than the reference flow rate Qa, the outlet 41 of the sub scroll 36 is opened and the main scroll 35 and the sub scroll 36 are utilized.

That is, when the intake air flow rate is greater than the reference flow rate Qa, as shown in FIG. 6, the compressor inlet negative pressure is lower than the reference negative pressure Pn, and the negative pressure switch 57
is ON. Therefore, the three-way solenoid valve 55 introduces the pressure at the outlet 40 of the main scroll 35 into the positive pressure chamber 53 of the actuator 48 . At this time, the pressure at the outlet 40 of the main scroll 35 has reached the maximum pressure pb, and the diaphragm 49 of the actuator 48 moves toward the atmospheric chamber 52 against the biasing force of the spring 54 due to this pressure. Therefore, the actuator 48 rotates the lever 46 in the direction of the arrow in FIG. 5 to rotate the valve body 43 from the B position to the A position shown in FIG. 4. Therefore, the outlet 41 of the sub scroll 36 is opened, and the intake air accelerated by the compressor wheel 21 flows through the main scroll 35 from the diffuser 33, enters the sub scroll 36 through the communication hole 39, and flows through the sub scroll 36.

As a result, the scroll capacity is increased compared to the case where only the main scroll 35 is used, and as shown in FIG. 7, high compressor efficiency can be obtained even in a large flow rate region. At this time, the seal member 47 attached to the periphery of the valve body 43
Since the tip of the valve body 43 is formed to be thin, loss due to blockage due to the thickness of the valve body 43 can be suppressed to a small level, and compressor efficiency can be maintained at a high level.

In this way, the scroll capacity can be varied by opening and closing the outlet 41 of the sub scroll 36 by the valve mechanism 67 based on the flow rate of the intake air, so high compressor efficiency can be maintained over a wide range of intake air flow rates. It is possible to obtain appropriate supercharging pressure. therefore,
It can improve engine output and fuel efficiency.

In addition, in the case of only the main scroll 35 and the case of the main scroll 35
In the case where both the auxiliary scroll 36 and the sub scroll 36 are used, the compressor efficiency and pressure ratio with respect to the intake air flow rate are reversed after a certain intake air flow rate, as shown in FIG.

Therefore, the reference flow rate Q is
When a is set, in the intake air flow rate range below the reference flow rate Qa, only the main scroll 35 is used (indicated by a solid line).
This results in a high compressor efficiency and pressure ratio, and the standard flow rate Qa
In a larger intake air flow range, the main scroll 35
High compressor efficiency and pressure ratio are obtained when both the auxiliary scroll 36 and the secondary scroll 36 are used (indicated by broken lines). Then, at the reference flow rate Qa, the compressor efficiency and pressure ratio when only the main scroll 35 is used are shifted to the compressor efficiency and pressure ratio when both the main scroll 35 and the sub scroll 36 are used. That is, by setting the reference flow rate to the boundary flow rate, high compressor efficiency and pressure ratio can be obtained in a wide range of intake air flow rates.

In this embodiment, the valve body 43 is turned ON-OFF.
Although an example has been shown in which the predetermined load of the spring 54 of the actuator 48 is made to match the maximum value Pb of the main scroll outlet pressure, the valve body 43 will change the opening degree of the sub scroll outlet as the air flow rate increases. By making a large movement, the compressor efficiency can be smoothly connected as shown by the solid line in FIG.

(Effects) According to the present invention, since the scroll capacity can be changed based on the flow rate of intake air, high compressor efficiency can be maintained over a wide range of intake air flow rates. Therefore, an appropriate boost pressure can be obtained over a wide range of intake air flow rates, and engine output and fuel efficiency can be improved.

In addition, in the above embodiment, the communication hole is formed near the shroud housing so as to be inclined in the outer circumferential direction from the sub-scroll side to the main scroll side, so that the air rotating the main scroll flows into the sub-scroll due to centrifugal force. This makes it possible to further improve compressor efficiency at low flow rates. In addition, since the valve body is formed into a cantilevered valve shape with its rotating end at the tip of the partition wall that separates the main scroll and sub scroll, the passage area through which air flows at low flow rates gradually increases from the main scroll to the pipe body. The expansion loss caused by the air flow can be kept small. Furthermore, a sealing member is attached to the tip of the bulkhead and the periphery of the valve body, and the sealing member on the periphery of the valve body is made thin at the tip. It is possible to prevent the influence of the sub-scroll by improving the adhesion with the valve body, and at the time of a large flow rate, it is possible to suppress the loss due to bronzeage due to the thickness of the valve body.Therefore, in the above embodiment, the intake air flow rate range is wide. As a result, compressor efficiency can be further increased, and energy output and fuel efficiency can be further improved.

[Brief explanation of the drawing]

1 to 8 are diagrams showing one embodiment of the present invention, in which FIG. 1 is a sectional view of the compressor, FIG. 2 is a side partial sectional view of the compressor, and FIG. 3 is the same as that of FIG. A arrow view,
Fig. 4 is a sectional view taken along the line IV-IV in Fig. 2, Fig. 5 is a schematic diagram showing the valve mechanism, and Fig. 6 shows the relationship between the intake air flow rate, compressor inlet negative pressure, and main scroll outlet pressure. Figure 7 is a characteristic diagram showing the relationship between the intake air flow rate and compressor efficiency, and Figure 8 is a characteristic diagram showing the relationship between the pressure ratio and compressor efficiency with respect to the intake air flow rate when only the main scroll is used and when only the main scroll is used. It is a characteristic diagram showing a comparison between the case where both scrolls are used. FIG. 9 is a sectional view showing a conventional turbocharger. 21-...-Compressor wheel, 25-------
- Compressor housing, 33...--Diffuser, 35...--One main scroll, 36--One sub-scroll, 39-----Series of through holes, 6---- - Valve mechanism.

Claims (1)

[Claims] A diffuser is formed in the compressor housing along the circumference near the tip of the compressor wheel, a main scroll is connected to the diffuser on the outer periphery of the diffuser, and the main scroll joins the main scroll at the exit of the main scroll and communicates with the main scroll. 1. A compressor comprising a sub-scroll that is separated and communicated by a hole, and a valve mechanism that can open and close an outlet of the sub-scroll based on the flow rate of intake air is provided at the confluence of the main scroll and the sub-scroll.