JPH1182036A - Exhaust turbo-charger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide satisfactory supercharging pressure characteristic over the whole range extending from low-speed rotating area to high-speed rotating area of an engine by providing a variable guide vane in a compressor inlet, and pressing the variable guide vane on the side of giving a rotation reverse to the rotating direction of a compressor impeller at the start of the engine. SOLUTION: When the engine rotating speed in starting is low, a variable guide vane 12 is turned and held in a direction of carrying air to a compressor impeller 3 by reverse rotation by the spring of an actuator 13. Thus, the air is carried into the impeller 3 by reverse rotation to enhance the supercharging pressure. When the engine rotating speed is gradually increased, and the supercharging pressure is increased by the spring force of the actuator 13, the spring is contracted to move a rod 14, and the variable guide vane 12 is gradually rotated by a rotating mechanism 15. The inflow angle of the air carried into the impeller 3 by the rotation of the variable guide vane 12 is successively changed from reverse rotation side to axial side and to normal rotation side to prevent the supercharging pressure from being excessively increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust turbocharger in which a compressor is rotated and supercharged by a turbine rotated by the energy of exhaust gas of an automobile engine, and more particularly to an exhaust turbocharger which controls the pressure of a compressor. The present invention relates to an exhaust turbocharger having improved supercharging pressure characteristics of a turbocharger.

[0002]

2. Description of the Related Art Various types of conventional exhaust turbochargers are known.

[0003] For example, a radial turbine is usually used as an exhaust turbocharger utilizing exhaust gas of an automobile engine. Exhaust gas from an exhaust cylinder of the engine is supplied to a radial turbine to rotate the turbine, drive a compressor on the same shaft, and send air compressed by the compressor to an intake pipe of the engine. However, since the engine displacement is small in the low and medium speed range of the engine, the turbine speed is low and the supercharging pressure of the coaxially mounted compressor cannot be increased. There was a problem that could not be done. In order to solve this problem, a relatively small-capacity turbine adapted to a low engine speed range is used.

In this case, when the engine speed is high, the exhaust gas flow rate is large and the turbine speed becomes too high.
A wastegate valve is provided on the turbine inlet side, and when the supercharging pressure becomes higher than a predetermined value, the opening of the wastegate valve is increased to release a part of the exhaust gas and to suppress the supercharging pressure from becoming excessive. .

[0005] Further, there is a type in which a nozzle blade having a variable angle is provided at an inlet of a turbine impeller so that the rotation speed of the turbine can be adjusted and the supercharging pressure is controlled. In this system, when the exhaust pressure is low and the exhaust flow rate is low at low engine speeds, the angle between the nozzle blade and the circumferential direction is controlled to be small, and the exhaust gas flow rate is increased to increase the turbine speed. Since it can be increased, the supercharging effect is easily obtained even when the engine speed is low. Also, when the exhaust pressure is high and the exhaust flow rate is high at high engine speed, the angle between the nozzle blade and the circumferential direction is increased to control the nozzle area to increase, and the turbine speed becomes too high. And reduce the exhaust resistance of the engine.

Further, as disclosed in JP-A-61-205330, as a supercharger for a marine diesel engine, a variable nozzle ring is provided at an exhaust gas inlet of a supercharger, an inlet guide vane is provided at a blower inlet, and a variable diffuser is provided at a blower outlet. Rings are provided, each rotation angle, turbocharger rotation speed, blower outlet pressure and temperature, differential pressure between blower swirl chamber outer wall pressure and inner wall pressure, and outer wall pressure, exhaust gas inlet temperature, engine Detects the number of revolutions and fuel flow rate, and controls the amount of air supplied to the engine and the supercharging pressure by linking the rotation angles of the variable nozzle ring, inlet guide vane, and variable diffuser ring to maximize the supercharger efficiency. Is known.

In this control method, first, when the engine is operated, it is assumed that the engine is operated at the maximum continuous output, and the rotation angles of the variable nozzle ring, the inlet guide vane, and the variable diffuser ring are set. Next, the fuel flow rate of the engine is detected, and the rotation angles of the variable nozzle ring, inlet guide vane, and variable diffuser ring of the supercharger are controlled so that the engine is operated with the minimum fuel flow rate.

[0008]

In the above-described conventional supercharging pressure control method using a wastegate valve on the turbine inlet side, the exhaust pressure that is bypassed when the engine is rotating at a high speed and the energy lost are reduced by the supercharging pressure. Therefore, there has been a problem that the turbine inlet pressure increases and the high-speed performance is impaired. Further, since a relatively small-capacity turbine is used for the engine, the turbine must be manufactured in accordance with the engine capacity, and there is a problem that the number of types of turbines increases and the manufacturing cost increases.

Further, in an exhaust turbocharger in which a nozzle blade is provided at an inlet of a turbine impeller so that the rotation speed of the turbine can be adjusted, the nozzle blade is disposed in a region where a fluid velocity is relatively high. In addition, there is a problem that the resistance loss of the fluid tends to increase, the efficiency of the turbine decreases, the turbine inlet pressure increases, and the high-speed performance is impaired. Further, the temperature of the turbine side of the turbocharger becomes high due to exhaust gas from the engine. The clearance between the nozzle vanes and the scroll casing is designed to be kept constant when the turbocharger becomes hot. Therefore, when the supercharger temperature is low, such as when starting the engine, there is a problem that the clearance between the nozzle blades and the scroll casing is widened, the turbine efficiency is significantly reduced, and a sufficient supercharging pressure cannot be obtained.

Further, in a method of controlling a supercharger for a marine vessel using a variable nozzle ring, an inlet guide vane, and a variable diffuser ring, the engine is operated at a constant speed in many cases. The supercharger is controlled so that the fuel supplied when operated is minimized. Therefore, a method of controlling the supercharging pressure in which the load condition changes frequently, such as in an automobile engine, is not considered.

An object of the present invention is to increase the discharge pressure of the compressor of the exhaust turbocharger, that is, the supercharging pressure, when the engine speed of the automobile engine is low, and to increase the supercharging pressure at the high engine speed. The supercharged pressure characteristic is realized with a simple structure over a wide range of operating conditions from the low speed range to the high speed range of the engine, The purpose is to prevent the supply pressure from becoming too high.

[0012]

In order to achieve the above object, an exhaust turbocharger comprising a turbine driven by exhaust gas of an engine and a compressor which supercharges a cylinder of the engine by driving the turbine is provided. Equipped with a variable guide vane rotatably supported at the compressor inlet and an actuator that rotates the variable guide vane by supercharging pressure, and when the engine starts, the variable guide vane turns in the direction opposite to the rotation direction of the compressor impeller. The variable guide vanes are pressed against the application side by an actuator, and the variable guide vanes are rotationally driven from the reverse swivel side to the forward swivel side in the direction of air inflow from the variable guide vanes as the supercharging pressure increases.

Further, the supercharging pressure is increased by the exhaust turbo supercharger, and the variable guide vane is rotated in a direction opposite to the rotation direction of the compressor impeller until the supercharging pressure P2 is slightly lower than the supercharging pressure P1 at the intercept point. The variable guide vane is rotated from the reverse turning side to the normal turning side after reaching the supercharging pressure P2 by the actuator.

Further, a waste gate valve is disposed at the turbine inlet of the exhaust turbocharger to prevent a part of the exhaust gas from being released by the supercharging pressure and to suppress the supercharging pressure from becoming excessive, and the wastegate valve is operated. Is higher than the supercharging pressure P1 at the intercept point.

An introduction port for introducing a supercharging pressure to an actuator for rotating the variable guide vane, or a valve which opens when the supercharging pressure P1 at the intercept point is obtained, is provided in the introduction passage. The variable guide vane is pressed by an actuator on the side that gives a turn in the direction opposite to the rotation direction of the compressor impeller by an actuator until the supercharging pressure increases and reaches the supercharging pressure P1, and the valve opens at the supercharging pressure P1 and the supercharging pressure is introduced. The variable guide vane is driven to rotate from the reverse turning side to the normal turning side.

Further, in an exhaust turbocharger comprising a turbine driven by exhaust gas of an engine and a compressor which supercharges a cylinder of the engine by driving the turbine, a variable guide vane rotatably supported at a compressor inlet. And an actuator for rotating the variable guide vane by the supercharging pressure, and the actuator is connected to a pressure introduction passage for guiding two supercharging pressures of a pressure on the compressor impeller and a compressor outlet pressure,
A valve means that opens in the direction to introduce the supercharging pressure when the throttle valve opens to close is provided in the pressure introduction passage that introduces the compressor outlet pressure.In normal operation, the variable guide vane is rotated by the pressure on the compressor impeller. The variable guide vane is driven to rotate forward by the compressor outlet pressure when the throttle valve is opened and closed.

As described above, at the compressor inlet of the exhaust turbocharger, a variable guide vane that is rotationally driven by an actuator that operates when a supercharging pressure is applied is installed. When the engine is started, the variable guide vane is held by an actuator on a side that gives a turn in a direction opposite to the rotation direction of the compressor impeller. When the engine is started and the exhaust gas of the engine drives the turbine of the exhaust turbocharger, the supercharging pressure is increased by the compressor. When the supercharging pressure is applied to the actuator, the variable guide vanes move the air flowing into the compressor impeller. Is driven to rotate in such a manner that the inflow direction is from the reverse turning side to the axial direction side, and then to the forward turning side.
Further, the actuator is regulated so that the variable guide vane does not rotate from the forward turning direction to the direction closing the flow path of the compressor inlet.

When the engine is operated at a low rotational speed in the exhaust turbocharger configured as described above, air flows into the impeller of the compressor in reverse rotation, so that a variable guide vane is provided. When the turbine speed is the same, the exhaust pressure of the compressor, i.e., the supercharging pressure, can be increased as compared with a turbocharger having no exhaust gas. Then, when the engine speed increases and the variable guide vanes rotate, the inflow angle of the air flowing into the impeller of the compressor changes from the reverse turning side to the axial direction side, and then to the forward turning side. When air flows into the compressor from the axial direction side, the same supercharging pressure as that of an exhaust turbocharger without variable guide vanes is obtained, and the supercharging pressure becomes too high by flowing in a forward swirl. Can be suppressed.

Further, the supercharging pressure is increased by the exhaust turbo supercharger, and the supercharging pressure P slightly lower than the supercharging pressure required by the engine, that is, the supercharging pressure P1 at the intercept point.
The variable guide vane is held by an actuator so that air flows into the compressor impeller in reverse rotation until the pressure reaches 2, and after reaching the supercharging pressure P2, the variable guide vane is driven to rotate from the reverse rotation side to the forward rotation side. By doing
The variable guide vanes allow air to flow in a state in which the compressor impeller is most reversely swirled up to the supercharging pressure P2. Therefore, the supercharging pressure from the low speed range to the medium speed range of the engine is further increased. can do. In other words, the response performance in the low and middle engine speed range is improved. When the supercharging pressure exceeds P2, the variable guide vane is driven to rotate from the reverse turning side to the normal turning side, so that the supercharging pressure can be prevented from becoming too high.

In addition, a wastegate valve is disposed at the turbine inlet, and the supercharging pressure at which the wastegate valve operates is set higher than the supercharging pressure P1 at the intercept point, so that the variable guide vane causes a forward swirl for some reason. If the engine cannot rotate in the direction, the supercharging pressure becomes higher than the supercharging pressure P1 at the intercept point according to the engine speed. However, when the boost pressure at the turbine inlet becomes higher than the supercharging pressure P1 at the intercept point, the wastegate valve that allows the exhaust gas of the engine to escape operates.
It is possible to prevent the turbine speed from decreasing and the supercharging pressure from becoming too high. That is, it is possible to protect the engine without increasing the pressure to a level higher than the maximum supercharging pressure determined for engine protection.

Further, by providing a valve which opens when the supercharging pressure P1 at the intercept point is provided in the inlet or the introduction passage for introducing the supercharging pressure of the actuator for rotating the variable guide vane, the supercharging pressure is increased. Until P1, the valve is closed, so that no supercharging pressure is applied to the actuator. Therefore, the variable guide vane is pressed and held by the actuator on the side that gives a turn in the direction opposite to the rotation direction of the compressor impeller. That is,
The engine speed until reaching the supercharging pressure P1 at the intercept point can be reduced, and the time required until the supercharging pressure P1 is reached is greatly reduced. When the charging pressure becomes higher than the supercharging pressure P1 at the intercept point, the valve opens and the supercharging pressure P1 is rapidly applied to the actuator, so that the variable guide vane rotates in a direction in which air flows from the reverse turning side to the forward turning side at a high rotation speed. Drive.

Further, the actuator for rotatingly driving the variable guide vane includes a pressure on the compressor impeller,
A pressure introduction passage for leading two supercharging pressures of the compressor outlet pressure is connected. In normal operation, the actuator rotates by the pressure on the compressor impeller, and the variable guide vane is rotationally driven by the impeller of the compressor from the reverse turning side to the forward turning side or from the forward turning side to the reverse turning side. . The pressure introduction passage for introducing the compressor outlet pressure is provided with a valve means that is linked to the throttle valve and opens in a direction for introducing the supercharging pressure when the throttle valve is closed from open.

When the vehicle is in an operating state, for example, when sudden braking is performed during high-speed operation, the throttle valve is changed from open to closed, so that the compressor flow rate suddenly decreases, and the exhaust turbocharger is operated at high speed. As a result, the compressor may approach the surging region of the compressor or the boost pressure may rise rapidly. In such an operation state, the valve in the pressure introduction passage for introducing the compressor outlet pressure is opened, and the variable guide vane is driven to rotate in the forward turning direction, whereby the supercharging pressure can be suppressed in a direction to prevent surging. .

Therefore, a variable guide vane, which is driven to rotate by the supercharging pressure, is disposed at the compressor inlet, and when the engine is started, the variable guide vane is pressed by an actuator against a side that gives a rotation in a direction opposite to the rotation direction of the compressor impeller. The supercharging pressure controls the compressor's supercharging pressure by rotating the variable guide vane from the reverse swivel side to the forward swivel side to change the air inflow direction from the variable guide vane, thereby supercharging when the engine speed is low. When the pressure is increased and the engine speed is high, the supercharging pressure can be prevented from becoming too high. Therefore, good supercharging pressure characteristics can be obtained over a wide range of operating conditions from a low-speed rotation range to a high-speed rotation range of the engine, and an exhaust turbocharger that operates on the safe side by preventing the supercharging pressure from becoming too high. Can be obtained.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of an exhaust turbocharger according to an embodiment of the present invention. As shown in the figure, a turbine impeller 4 and a compressor impeller 3 are connected to both ends of a rotating shaft 5 of the exhaust turbocharger 1. The turbine impeller 4 is housed in a turbine casing 6, and the turbine casing 6 is provided with an inlet 7 for introducing exhaust gas from the engine 2 and an outlet 8 for discharging exhaust gas. The compressor impeller 3 is housed in a compressor casing 9, and the compressor casing 9 has an inlet 10 for introducing air, and an outlet 11 for supplying air compressed by the compressor impeller 3 and the compressor casing 9 to the engine 2. Have been.

A variable guide vane 12 is provided at the compressor inlet 10. The variable guide vane 12
The blade is connected to a rotation mechanism 15 via a variable guide vane actuator 13 for rotatingly driving the blades and a variable guide vane rod 14. In the pressure operating chamber 16 of the variable guide vane actuator 13, the supercharging pressure on the compressor exhaust side is supplied from the supercharging pressure inlet 17A to the supercharging pressure introducing passage 1.
7B. When the supercharging pressure is introduced, the rod 14 moves and the rotating mechanism 15 rotates the variable guide vane 12.

The air flowing from the compressor inlet 10 changes the inflow angle of the air flowing into the compressor impeller 3 by the variable guide vanes 12 and is compressed by the compressor impeller 3 and the compressor casing 9.
From the compressor outlet 11, the intake passage 18 of the engine 2
From the engine 2. Exhaust gas discharged from the engine 2 is guided to the turbine casing 6 of the exhaust turbocharger 1 via an exhaust passage 19.

Next, the operation of one embodiment of the present invention will be described.

When the engine speed is low at the time of starting the engine, the variable guide vane 12 is held by the spring force of the spring 13A of the actuator 13 for the variable guide vane in the direction in which air flows into the compressor impeller 3 in reverse rotation. Have been. As a result, air flows into the compressor impeller 3 in reverse rotation, so that the exhaust pressure of the compressor, that is, the supercharging pressure can be increased. Here, the inflow angle of the air flowing into the compressor impeller 3 by the variable guide vanes 12 and the spring force of the actuator 13 are selected according to the characteristics of the engine 1.

When the engine speed gradually increases, the supercharging pressure becomes larger than the spring force of the variable guide vane actuator 13, and the spring 13A is contracted. The vane 12 is gradually rotated. FIG. 2 is a conceptual diagram showing a movable state of the variable guide vane. 2A shows a forward turning side, FIG. 2B shows an axial direction side, and FIG. 2C shows a reverse turning side. When the variable guide vane 12 is driven to rotate, the inflow angle of the air flowing into the compressor impeller 3 changes from the reverse turning side to the axial direction side, and then to the forward turning side. However, the actuator is regulated by the variable guide vane actuator 13 so as not to be further rotated and driven to block the flow path from the forward turning direction.

FIG. 3 shows the flow rate characteristics of the exhaust turbocharger compressor according to one embodiment of the present invention when the variable guide vane 12 is driven to rotate. The horizontal axis shows the compressor air flow,
The vertical axis shows the compression ratio. The solid line indicates that the variable guide vanes 12 are arranged at the compressor inlet 10, and the one without the broken line is shown. When reverse turning is given, the same rotation speed,
When compared at the same air flow rate, the supercharging pressure is higher when the variable guide vane 12 is attached, and the difference between the supercharging pressures decreases as the rotation speed increases. When flowing in from the axial direction, the supercharging pressure is the same as that without the variable guide vanes. When the forward rotation is given, the supercharging pressure becomes smaller than that without the variable guide vanes 12.

As described above, when the variable guide vane 12 is driven to rotate and air flows into the compressor impeller 3 in reverse rotation, the supercharging pressure can be made higher than that without the variable guide vane 12. it can. In addition, when air flows in from the axial direction, the same supercharging pressure as when the variable guide vanes are not provided is obtained, and when the air flows in forward rotation, it is possible to suppress the supercharging pressure from becoming too high. it can.

FIG. 4 is a conceptual diagram showing the operating characteristics of the exhaust turbocharger compressor according to one embodiment of the present invention. FIG. 3 is a plot of the compression ratio at the same flow rate from the compressor flow rate characteristics in FIG. 3, where the horizontal axis indicates the air flow rate and the vertical axis indicates the compression ratio of the compressor. (A) of the drawing shows the operating characteristics of a standard type exhaust turbocharger, and (b) shows a variable guide vane 12 disposed at a compressor inlet 10 according to an embodiment of the present invention. The point indicated by A in the figure is the one when it flows into the compressor impeller 3 from the axial direction. Variable guide vane 12
By providing reverse rotation to the compressor impeller 3, it is possible to increase the compression ratio of the compressor at a low air flow rate, that is, at a low engine speed, and to improve the supercharging pressure characteristics at a low engine speed range. . Also, on the large flow side,
That is, the compression ratio can be suppressed by giving the normal turning in the high engine speed range.

Although not shown, an exhaust turbocharger according to another embodiment of the present invention will be described. The difference from the invention of FIG. 1 is in the method of driving the variable guide vane 12 to rotate. That is, according to the present invention, the supercharging pressure P2 lower than the supercharging pressure P1 at the intercept point from the start of the engine.
Up to this point, the spring constant of the spring 13A is set so that the spring force of the spring 13A of the actuator 13 is larger than the supercharging pressure P2.

Thus, during the period from the start to the supercharging pressure P2, the variable guide vane 12 is held at the initially set vane angle by the spring force of the spring 13A. That is, the inflow angle of the air flowing into the compressor impeller 3 is:
The direction in which the most reverse turn was applied can be maintained. Supercharging pressure P
After reaching 2, the supercharging pressure becomes larger than the spring force of the spring 13A, so that the rod 14 is moved and the rotating mechanism 15 is used to change the air inflow direction from the reverse turning side to the forward turning side. The vane 12 is driven to rotate.

FIG. 5 shows the compressor flow characteristics of the exhaust turbocharger according to another embodiment of the present invention having the above-described structure.
Shown in When the rotation speed of the compressor is increased while the reverse rotation is given, it can be seen that the compression ratio increases when compared at the same air flow rate. The operating characteristics based on the compressor flow characteristics are shown in FIG. Compared to FIG. 4B,
It is possible to increase the supercharging pressure on the low and medium flow rates, that is, to improve the supercharging pressure characteristics in the low and medium engine speed ranges and to improve the response performance in the low and medium engine speed ranges. .

FIG. 6 shows a schematic structure of an exhaust turbocharger according to another embodiment of the present invention. 1 having the same functions as those in FIG. The exhaust turbocharger 1 includes a compressor impeller 3, a turbine impeller 4,
The rotary shaft 5, a wastegate valve 21, an actuator 22 for driving the wastegate valve 21, a variable guide vane 12, and an actuator 13 for driving the variable guide vane 12 are provided. Exhaust gas discharged from the engine 2 is guided to the turbine casing 6 of the exhaust turbocharger 1 via an exhaust passage 19. A bypass passage 20 that bypasses the exhaust turbine impeller 4 is formed in the turbine casing 6, and a waste gate valve 21 is provided in the bypass passage 20.

The wastegate valve 21 includes a wastegate valve actuator 22 for opening and closing the wastegate valve 21 and a wastegate valve rod 2.
3 are connected. The supercharging pressure on the exhaust side of the compressor is introduced into the pressure operating chamber 24 of the wastegate valve actuator 22 from a supercharging pressure inlet 25A via a supercharging pressure introducing passage 25B. The supercharging pressure is introduced from the supercharging pressure inlet 25A into the pressure working chamber 24 via the supercharging pressure introducing passage 25, and when the supercharging pressure exceeds the supercharging pressure at the intercept point, the rod 23 moves to open the waste gate valve 21. It has become.

In the exhaust turbocharger configured as described above, if the variable guide vane 12 cannot rotate in the direction of flowing forward turning for any reason, the supercharging pressure increases with the engine speed. Higher than the supercharging pressure at In this case, when the supercharging pressure at the turbine inlet 7 becomes higher than the supercharging pressure at the intercept point, the engine 2
Since the wastegate valve 21 for releasing the exhaust gas is disposed, it is possible to prevent the supercharging pressure from becoming too high.

FIG. 7 shows a schematic structure of an exhaust turbocharger according to another embodiment of the present invention. The difference from FIG. 1 is that a valve that opens when the supercharging pressure P1 at the intercept point reaches the supercharging pressure introduction passage 17B or the inlet 17A for introducing the supercharging pressure of the actuator 13 that rotates the variable guide vane 12. Means 26 is provided, and the variable guide vane 12 is pressed and held by an actuator on the side that gives a turn in the direction opposite to the rotation direction of the compressor impeller 3 until the supercharging pressure P1 is reached. The variable guide vane 12 is driven to rotate toward the forward turning side.

As a result, the valve is closed up to the supercharging pressure P1 at the intercept point.
No supercharging pressure is applied to the pressure working chamber 16. Therefore, the variable guide vane 12 is held at the initially set vane angle by the spring force of the spring 13A of the actuator 13. The supercharging pressure is the supercharging pressure P at the intercept point.
If it is higher than 1, the valve opens and the actuator 13
Because the supercharging pressure P1 is suddenly applied to the pressure working chamber 16 of
At a high rotation speed, the variable guide vane 12 can be driven to rotate in a direction in which air flows from the reverse turning side to the normal turning side.

FIG. 4 shows the operating characteristics of the compressor of the present invention.
(D). As compared with FIG. 4C, the compression ratio in the middle flow rate region can be increased. That is, the engine speed at which the supercharging pressure P1 at the intercept point is reached can be reduced, and the time required to reach the supercharging pressure P1 at the intercept point can be shortened. Therefore, there is an effect that the low and medium speed torque characteristics of the engine and the response during acceleration can be improved.

FIG. 8 shows a schematic configuration of an exhaust turbocharger according to another embodiment of the present invention. Those having the same function are denoted by the same reference numerals and description thereof is omitted. In FIG. 6, the exhaust turbocharger 1 includes a compressor impeller 3, a turbine impeller 4, a rotating shaft 5, a wastegate valve 21
And a variable guide vane 12, and an actuator 13 for driving the variable guide vane 12. The actuator 13 for rotating and driving the variable guide vane 12 includes a pressure introducing passage 27 for introducing pressure on the compressor impeller 3, Pressure introduction passage 17 for guiding the supercharging pressure of the outlet pressure
B is connected. Further, a valve means 28 is provided in the pressure introducing passage 17B for introducing the compressor outlet pressure, in conjunction with the throttle valve, and opening in a direction for introducing the supercharging pressure when the throttle valve is opened to closed.

The exhaust turbocharger 1 configured as described above
In the normal operation, the actuator 13 is rotated by the pressure on the compressor impeller 3, and the variable guide vane 12 is moved to the compressor impeller 3 from the reverse turning side to the normal turning side or from the normal turning side to the reverse turning side. It is driven to rotate.
In the driving state of the automobile, for example, when sudden braking is performed during high-speed operation, the throttle valve is changed from open to closed, so that the compressor flow rate suddenly decreases, and the exhaust turbocharger 1 is operated at high speed. It may approach the surging region of the compressor or the boost pressure may rise sharply.

In such an operation state, when the valve 28 of the pressure introducing passage 27 for introducing the compressor outlet pressure is opened, the compressor outlet pressure is larger than the pressure on the compressor impeller. It can be driven to rotate in the forward turning direction. As a result, the supercharging pressure can be suppressed, so that it does not approach the surging region of the compressor.

The actuator 13 for rotating the variable guide vane 12 in the above embodiment is provided with a supercharging pressure and a spring 13A.
Although the structure for balancing the spring force is adopted, the present invention is not limited to this, and any structure may be used as long as an operation equivalent to a spring is performed.

Accordingly, the variable guide vane 12 which is driven to rotate at the compressor inlet 10 is arranged, and the variable guide vane 12 is driven to rotate, so that the supercharging pressure of the compressor can be controlled. At a high engine speed, it is possible to prevent the boost pressure from becoming too high. Therefore, good supercharging pressure characteristics can be obtained over a wide range of operating conditions from a low-speed rotation range to a high-speed rotation range of the engine 1, and further, the supercharging pressure is prevented from becoming too high, and the exhaust turbocharging that operates on the safe side Machine 1 can be obtained.

[0049]

As described above, according to the present invention, the supercharging pressure of the compressor can be increased when the engine 2 is started or when the engine speed is low. It can be suppressed that the height becomes too high. Therefore, good supercharging pressure characteristics can be obtained over a wide range of operating conditions from a low-speed rotation range to a high-speed rotation range of the engine 2, and further, the turbocharged turbocharger that operates on the safe side by preventing the supercharging pressure from becoming too high Machine 1 can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of an exhaust turbocharger according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a movable state of a variable guide vane of FIG.

FIG. 3 is a diagram showing a compressor flow rate characteristic of an exhaust turbocharger according to one embodiment of the present invention.

FIG. 4 is a diagram showing a conceptual diagram of operating characteristics of a compressor according to one embodiment of the present invention.

FIG. 5 is a diagram showing a compressor flow rate characteristic of the exhaust turbocharger of one embodiment of the present invention.

FIG. 6 is a diagram showing a schematic configuration of an exhaust turbocharger according to another embodiment of the present invention.

FIG. 7 is a diagram showing a schematic configuration of an exhaust turbocharger according to another embodiment of the present invention.

FIG. 8 is a diagram showing a schematic configuration of an exhaust turbocharger according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Exhaust turbocharger, 2 ... Engine, 3 ... Compressor impeller, 4 ... Turbine impeller, 5 ... Rotating shaft, 6 ... Turbine casing, 7 ... Exhaust gas inlet, 8 ... Exhaust gas outlet, 9 ... Compressor casing Reference numeral 10: compressor inlet, 11: compressor outlet, 12: variable guide vane, 13: actuator for variable guide vane, 13A
... Spring, 14 ... Rod, 15 ... Rotating mechanism, 16 ... Pressure working chamber for variable guide vane, 17A ... Charging pressure inlet for variable guide vane, 17B ... Charging pressure introducing passage for variable guide vane, 18 ... Suction passage , 19 ... exhaust passage, 20 ... bypass passage, 21 ... wastegate valve, 22 ... wastegate valve actuator, 23 ... wastegate valve rod, 24 ... wastegate valve pressure working chamber, 25A ... wastegate valve excess Supply pressure introduction port, 25B ... Supercharge pressure introduction passage for waste gate valve, 26 ... Valve means, 27 ... Pressure introduction passage, 28 ... Valve means.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuo Udagawa 2520 Odaiba, Hitachinaka-shi, Ibaraki Prefecture Within the Automotive Equipment Division of Hitachi, Ltd.

Claims (1)

[Claims] An exhaust turbocharger comprising a turbine driven by exhaust gas of an engine and a compressor charged into a cylinder of the engine by driving the turbine, a variable turbocharger rotatably supported at an inlet of the compressor. A guide vane, an actuator for rotating the variable guide vane by a supercharging pressure, and when the engine is started, the variable guide vane is pressed by the actuator against a side that gives a rotation in a direction opposite to the rotation direction of the compressor impeller, An exhaust turbocharger characterized by rotating the variable guide vane from a reverse swivel side to a forward swivel side with respect to the direction of inflow of air from the variable guide vane as the supercharging pressure increases.