JPS62159732A - Turbo charger - Google Patents

Abstract

PURPOSE:To vary the capacity of a scroll according to the operating state of an engine and to improve compression efficiency, by a method wherein a resilient member, operated according to an intake air flow rate, is situated in the scroll of the compression housing of a turbo charger. CONSTITUTION:A parallel wall diffuser 8 is formed between a compressor housing 5 and a bearing housing 6 fastened to the housing 5, and a scroll 9 is formed in the housing 5 in a manner to be connected to a diffuser 8. In this case, a partition wall 16 formed by a resilient member is formed in the scroll 9 in a manner to be nipped between the two housings 5 and 6. During low speed rotation of an engine, a 3-way valve 20 is switched so as to intercommunicate pressure introduction holes 17 and 18, and the partition wall 16 is brought into a slightly expanded state. Meanwhile, during high speed rotation, the 3-way valve 20 is switched so as to open the two introduction holes 17 and 18 to the open air, and the partition wall 16 is forced into firm adhesion to the inner wall of the housing 5.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a turbocharger in which the capacity of a scroll of a compressor housing is variable.

(Prior Art) Conventionally, there is a turbocharger of this type, for example, as shown in FIG.
This is disclosed in Japanese Patent No. 3232. In FIG. 8, ■ is an impeller coaxially attached to the turbine rotor 2 via the rotating shaft 3, 4 is a turbine housing, 5 is a compressor housing, 6 is attached to these housings 4 and 5, respectively, Furthermore, it is a bearing housing in which a bearing (not shown) is supported.

Air flowing into the impeller l from the air inflow lower part of the compressor housing 5 is guided from the impeller l to the diffuser part 8, where the velocity energy is converted into pressure energy, and then sent out from the scroll part 9 to the compressor outlet 10. .

11 is a housing wall 5 forming the diffuser part 8
A partition plate 13 is provided on the outside of the housing wall 5A and rotatably held by a taker I2.

A plurality of openings 14 are bored in the partition plate 13, and the plurality of openings 14 and the above-mentioned opening 11 are made to coincide with each other depending on the rotational position of the partition plate 13, so that the diffuser section can be opened through the partition plate 13. 8 can communicate with the outside world.

In a turbocharger having a compressor configured in this way, when the engine is in a low speed range, the opening 11 is closed by rotating the partition plate 13, and only the inflow air from the inflow lower is compressed. Thus, supercharging pressure is supplied to the engine from the outlet 10 via the scroll 9. On the other hand, when the engine speed exceeds a predetermined value,
By rotating the partition plate 13 again, both openings 11
and 14 and introduce atmospheric air into the diffuser section 8 to increase the compressed air flow rate.

(Problem to be solved by this invention) However,
In such a conventional turbocharger, the opening 1
The flow velocity when air is introduced into the high-speed side of the diffuser section 8 in which the diffuser section 1 is provided is close to the speed of sound;
In response to such high-speed swirling flow, outside air is sucked in from the inlet side of the diffuser section 8, so a large fluid loss occurs in the diffuser section 8 due to the mixing of both slow-speed flows, and furthermore, velocity energy is converted into pressure energy. Since the pressure recovery rate is impaired, compression efficiency in a large flow range deteriorates significantly, resulting in a problem in that engine torque decreases.

(Means for Solving the Problems) This invention was made with the aim of solving these problems, and is driven by the exhaust energy of the engine and introduces intake air from the inlet of the compressor housing. In a turbocharger that pressurizes intake air by rotating an impeller and supplies pressurized air to an engine from a scroll of a compressor housing, an elastic member is provided in the scroll and makes the capacity of the scroll variable;
A drive means for driving the elastic member so as to vary the capacity of the scroll according to the intake air flow rate.

(Function) In the present invention having such a configuration, the elastic member is driven by the driving means in accordance with the intake air flow rate, thereby making the scroll capacity variable. Therefore, the capacity of the scroll can be reduced when the flow rate is small, and the capacity of the scroll can be increased when the flow rate is large, so that good compression efficiency can be ensured even when the flow rate is small and when the flow rate is large.

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

1 to 3 are diagrams showing a first embodiment of the present invention.

Note that the same components as in the conventional example will be described with the same reference numerals.

First, to explain the configuration, in FIG. 1, 1 is an impeller coaxially connected to a turbine rotor 2 via a rotating shaft 3, and this impeller 1 rotates with a predetermined clearance in the compressor housing 5. It is stored freely. The compressor housing 5 is fastened to a bearing housing 6 via a V-band 15, and the rotating shaft 3 is supported within the bearing housing 6 via a bearing (not shown). A parallel wall diffuser 8 is formed between the bearing housing 6 and the compressor housing 5, and a scroll 9 is formed within the compressor housing 5 in succession to the parallel wall diffuser 8. Note that this scroll 9 has a sufficiently large capacity compared to the discharge capacity of the impeller 1.

Here, as shown in FIGS. 1 and 2, a partition wall 16 made of an elastic member is provided inside the scroll 9.
One end of the partition wall 16 is sandwiched and fixed between the compressor housing 5 and the bearing housing 6, and the other end is fixed to the outlet portion 10 of the scroll 9. Therefore, by expanding and contracting the partition wall 16 within the scroll 9, the capacity of the scroll is made variable. 1
Reference numeral 7 indicates a pressure introduction hole formed in the compressor housing 5, and reference numeral 18 indicates a pressure introduction hole formed in the bearing housing 6. One pressure introduction hole 17 communicates with a three-way valve (driving means) 20 through one communication path 19A, and the other pressure introduction hole 18 communicates with a three-way valve 20 through the other communication path 19B. There is. Therefore, partition wall 1
The scrolls 9A on the outer side of the scrolls 9A and the scrolls 9B of the eight parallel wall diffusers communicate with each other via the three-way valve 20 and their pressure introduction holes 17,18. Further, one communication path 19A is connected to the inlet portion 7 of the compressor housing 5.
It communicates with the air intake passage 21 through an air introduction passage 21, and an orifice 22 is formed in the middle of this air introduction passage 21. In this embodiment, the opening 11 of the housing wall 5A, the retainer 12, and the partition plate 13 having the opening 14 provided in the conventional example are all eliminated.

Next, the effect will be explained.

When the engine rotates at low speed, that is, when the compressor has a small flow rate, one pressure introduction hole 17 and the other pressure introduction hole 1
The three-way valve 20 is driven so as to allow the two terminals to communicate with each other.

At this time, since the atmospheric air introduction passage 21 communicates with the outlet part 7 of the compressor housing 5 through the orifice 22, the pressure in the scroll 9A on the outside of the partition wall 16 is equal to the pressure in the scroll 9B on the parallel wall diffuser 8 side. Since the pressure is slightly lower than the pressure, the partition wall (elastic member) 16 is fixed in a slightly expanded state (see FIG. 1). In this state, the scroll 9 is maintained in a state corresponding to the walking distance,
As shown by S in FIG. 3, the compression efficiency at low flow rates is improved. That is, when the flow rate is small, the difference in flow velocity between the exit velocity of the parallel wall diffuser 8 and the average velocity within the scroll 9 is small or eliminated, so that mixing loss is reduced and compression efficiency is increased. Therefore, in the low rotational speed range of the engine, it is possible not only to increase the supercharging pressure and accelerate the start-up of supercharging, but also to improve responsiveness during acceleration.

On the other hand, when the engine rotates at high speed, that is, when the compressor has a large flow rate, the three-way valve 20 is driven so that each pressure introduction hole 17, 18 communicates with the atmosphere. When the compressor has a large flow rate, the pressure inside the scroll 9B on the side of the parallel wall diffuser 8 becomes greater than the pressure inside the scroll 9A on the outside of the partition wall 16, so the partition wall 16 comes into close contact with the inner wall of the compressor housing 5 due to this pressure difference. .

In this state, the scroll 9 has a large capacity, exhibits compressor characteristics as shown in FIG. 3, and improves compression efficiency at large flow rates. Therefore, the turbocharging efficiency can be improved and the back pressure of the engine can be lowered, so that the engine torque can be improved. Note that in the case of a gasoline engine, since the intake air temperature can be lowered and the occurrence of knocking can be suppressed, the output torque can be further improved.

Further, in this embodiment, the three-way valve 20 was used, but
If the pressure difference is controlled by a duty solenoid valve instead, the compressor efficiency in the middle speed range of the engine can be improved, as shown by M in FIG. Furthermore, if the pressure difference is controlled continuously, the compressor characteristics shown by the envelope line E in FIG. 3 can be obtained, and the efficiency can be obtained from the low speed range to the high speed range. Further, if a solenoid valve is used instead of the three-way valve 20, the scroll capacity changes with a predetermined time constant due to the orifice 22 when the solenoid valve is closed, making continuous control possible during acceleration. Furthermore, if the pressure introduction hole 18 is provided at an appropriate location of the parallel wall diffuser 8 (at a location lower than the pressure inside the scroll 9), the orifice 2
2 can be made unnecessary.

Next, FIGS. 4 and 5 show a second embodiment of the present invention.

In this embodiment, as shown in FIGS. 4 and 5, a bag-shaped or balloon-shaped elastic member (for example, rubber) 23 is provided along the exit portion 1o from the inlet of the scroll 9. A pressure chamber 24 is defined inside the bag (or balloon), and a pressure introduction port 23A is formed in the pressure chamber 24. The pressure introduction port 23A is connected to an introduction hole 5B formed in the compressor housing 5, and the introduction hole 5B communicates with an introduction passage 27 of a driving means 29, which will be described later (Fig. 5,
reference).

In FIG. 5, 25 is an electric pump that generates high-pressure air and sends it to the accumulator 26.
The high-pressure air in the accumulator 26 fed by the pump 5 is introduced into the pressure chamber 24 through an introduction passage 27 by a three-way valve 28 that is driven according to the operating state of the engine.

In addition, the above-mentioned electric pump 25 and accumulator 26.3
The direction valve 28 and the introduction passage 27 constitute a driving means 29.

Therefore, at low engine speeds and part loads,
That is, when the compressor has a small flow rate, the three-way valve 28 is driven to communicate the accumulator 26 and the pressure chamber 24, and the high pressure air in the accumulator 26 is transferred to the pressure chamber 24.
to inflate the elastic member 23.

In this state, the scroll 9 is maintained at a walking distance and has a shape suitable for a small flow rate.

On the other hand, when the engine is rotating at high speed, that is, when the compressor has a large flow rate, the three-way valve 28 is driven so that the pressure chamber 24 communicates with the atmosphere through the passage 27. When the compressor has a large flow rate, the pressure within the scroll 9 reaches the maximum supercharging pressure, which is greater than the pressure within the pressure chamber 24, so that the elastic member contracts due to this pressure difference. In this state, the scroll 9 has a large capacity 1, and the compression efficiency at a large flow rate is improved.

Other configurations and operations are similar to those of the previous embodiment.

Next, FIGS. 6 and 7 show a third embodiment of the present invention.

In FIG. 6, reference numeral 31 indicates a turbocharger, and the turbocharger 31 is connected to a turbine rotor 32 that is rotationally driven by exhaust energy from the engine, and is connected to the turbine rotor 32 via a rotating shaft 33.
The compressor impeller 34 rotates together with the rotating shaft 33 by the rotational drive of the compressor impeller 34, which pressurizes intake air and supplies it to the engine.

The large diameter portion of the rotating shaft 33 is provided with a pair of journal bearings 35A, 3.
5B, and a collar member 37 is fitted into the small diameter portion of the rotating shaft 33. A thrust bearing 38 is slidably fitted into the collar member 17 and receives the thrust force of the rotating shaft 33. Also,
Reference numeral 39 denotes a back plate that connects the bearing housing 36 and the compressor housing 40 with a V-hand 42 via a gasket 41;
A mechanical seal 43 is interposed between the rotary shaft 33 and the rotary shaft 33 . 44 is a lubricating oil supply passage formed in the bearing housing 36, and the lubricating oil is supplied through this supply passage 44.
The bearings 35A, 35B communicate with each other through oblique holes 45A, 45B, 45C.

38 respectively, and after lubricating these, the discharge port 4
It is discharged from 6.

Note that 47 represents a heat insulator interposed between the bearing housing 36 and the turbine housing 48, and 49 represents a seal ring interposed between the bearing housing 36 and the rotating shaft 33.

Here, a parallel wall diffuser 5o is formed between the back plate 39 and the compressor housing 40, and a scroll 5I is formed in the compressor housing 40 continuously from the parallel wall diffuser 5o. The inner circumferential wall 51A of the scroll 51 is formed so that its corners are approximately at right angles, and the inner circumferential wall 51C of the outlet portion 51B is also formed so that its corners are approximately at right angles. Further, as shown in FIG. 7, the scroll 51
At the winding start 51D, one end of a variable plate (elastic member) 52 is supported by a pin 53, and this variable plate 52 is composed of a leaf spring, and makes the capacity (cross-sectional area) of the scroll 51 variable. . The other end of the variable plate 52 is positioned by a pin 54 so as to be aligned with the inner circumferential wall 51C of the outlet portion 51B. Therefore, when the variable plate 52 is moved by an actuator (driving means, not shown) and a tensile force is applied thereto, the variable plate 52 moves to the position indicated by the solid line in FIG. 5, and the capacity of the scroll 51 decreases. On the other hand, when no tensile force is applied, the variable plate 52 moves toward the inner circumferential wall 51A of the scroll 51 due to the reaction force of the leaf spring.
Further, when the scroll 51 reaches the position indicated by the dotted line in FIG. 5 so as to come into close contact with the inner circumferential wall portion 51A, the capacity of the scroll 51 increases (see the arrow in FIG. 4).

Therefore, when the air flow rate is low, the variable Vi, 52 is moved to the position indicated by the solid line in FIG. 7 by moving an actuator (not shown). Therefore, at this time, since the capacity of the scroll 51 is reduced, the compression efficiency at a small flow rate is improved. On the other hand, when the air flow rate is large, the tension force by the actuator is not applied to the variable plate 52, and the variable plate 52 is brought into close contact with the inner circumferential wall 51A of the scroll 51 by the reaction force of the leaf spring, as indicated by the dotted line in FIG. move to position.

Therefore, at this time, since the capacity of the scroll 52 becomes large, the compression efficiency at a large flow rate becomes better.

(Effects) As explained above, according to the present invention, the volume of the scroll can be changed by driving the elastic member according to the air flow rate, so even when the flow rate is raw air or when the air flow rate is large. Compression efficiency can be increased. As a result, engine torque and acceleration response can be improved.

[Brief explanation of drawings]

1 to 3 are diagrams showing a first embodiment of a turbocharger according to the present invention, in which FIG. 1 is a cross-sectional view of a main part thereof, and FIG. 2 is a diagram showing its scroll and its elastic member, Third
The figure is a graph showing the relationship between flow rate and compressor efficiency, and Figures 4 and 5 are diagrams showing a second embodiment of the present invention. Figure 4 is a sectional view of the main part thereof, and Figure 5 is its FIGS. 6 and 7 are diagrams showing a scroll and its elastic member, and FIGS. 6 and 7 are diagrams showing a third embodiment of the present invention. FIG. 6 is a sectional view thereof, and FIG. 7 is a diagram showing the scroll and its variable plate. FIG. 8 is a cross-sectional view of a conventional turbocharger. 1... Impeller, 5... Compressor housing, 9...
・Scroll, 16...Elastic member, 20...3-way valve (driving means).

Claims (1)

[Claims] In a turbocharger that is driven by the exhaust energy of the engine, introduces intake air from the inlet of the compressor housing, pressurizes the intake air by rotating an impeller, and sends the pressurized air to the engine from the scroll of the compressor housing. A turbocharger comprising: an elastic member that makes the capacity of the scroll variable; and a drive means that drives the elastic member so as to make the capacity of the scroll variable in accordance with an intake air flow rate.