JP2002070569A - Supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent lubricating oil from leaking in a low load operation state of an engine in a supercharger. SOLUTION: This supercharger is so formed that a ring-shaped air chamber 33 is formed in a part positioned in the opposite side to the introduction side of exhaust gas in the turbine 19 and partitioned by a turbine 19 and a seal member 31, an air passage 34 connected from a scroll chamber 25 in a compressor 20 side to the air chamber 33 is formed, an atmosphere opening passage 35 opened to the outside is connected to the air passage 34, and a vacuum breaker 36 opened/closed by the compressor 20 according to the pressure of the feed air is installed in the opening end of the atmosphere opening passage 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mounted on an engine such as a ship or an automobile, rotates a turbine by a gas flow of exhaust gas, and the turbine drives a compressor to supply compressed intake air to the engine. Regarding supercharger.

[0002]

2. Description of the Related Art A marine diesel engine is equipped with a turbocharger as a device for increasing its output. This turbocharger guides the exhaust gas from the diesel engine to the blades of the turbine, turns the turbine with the gas flow, and turns the compressor installed on the same axis as the turbine, thereby compressing the intake air and burning the engine. It is sent to the room. As described above, the turbocharger sends a large amount of combustion air into the combustion chamber, thereby contributing to energy saving and enabling high output.

In this turbocharger, generally, a turbine is fixed to one end of a rotating shaft, while a compressor is fixed to multiple ends, and the rotating shaft is rotatably supported by a casing by a thrust bearing and a journal bearing. ing. An exhaust gas introduction passage for guiding exhaust gas to the turbine is connected to the casing, an exhaust gas exhaust passage is connected to the casing, and a suction air passage is connected to the compressor to the casing, and the intake air is supplied to the engine. Are connected to an air supply passage for supplying air to the combustion chamber.

Accordingly, the exhaust gas from the diesel engine is guided to the turbine through the exhaust gas introduction passage, rotates the turbine, and is discharged from the exhaust gas discharge passage.
By rotating a compressor provided on the same axis as the turbine, the air sucked from the intake air passage is compressed, and the compressed air can be sent to the combustion chamber through the air supply passage, increasing the output of the diesel engine. Becomes possible.

[0005]

When a diesel engine is operated at a high speed and a high load, the exhaust gas becomes high pressure by the above-mentioned turbocharger, and the rotor comprising a coaxial turbine and a compressor introduces the exhaust gas by the pressure. It is pressed with a large force on the side opposite to the passage, for example, on the compressor side along the axial direction of the rotating shaft. Then, a large force acts on the thrust bearing that supports the rotating shaft in the axial direction, and the reliability of the bearing may be reduced.
There is a possibility that the power loss due to the bearing increases and the performance of the supercharger deteriorates.

In order to solve such a problem, when a diesel engine is operated at a high speed and a high load, air compressed by a compressor is passed through an air passage to an air chamber on a side opposite to an exhaust gas introduction side in the turbine. By supplying the compressed air, the rotor receiving the pressure of the exhaust gas by the compressed air is pushed back to reduce the load on the thrust bearing, thereby preventing the bearing from being damaged and the performance from being reduced.

However, during idling operation of the diesel engine or low-speed / low-load operation of the diesel engine, the turbocharger does not function due to the low exhaust gas pressure, and the intake air is not compressed by the compressor. Due to the suction force, the air is in a negative pressure state in the air supply passage of the compressor. Then, due to the negative pressure, the air chamber on the side opposite to the exhaust gas introduction side in the turbine is sucked through the air passage described above to be in a negative pressure state, and the lubricating oil supplied to the bearing is also sucked and leaked. There's a problem.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a supercharger capable of preventing leakage of lubricating oil in a low-load operation state of an engine.

[0009]

According to a first aspect of the present invention, there is provided a supercharger in which a turbine is rotated by a gas flow of exhaust gas, and a compressor provided coaxially with the turbine. By rotating, in a supercharger for compressing and feeding intake air, an air chamber is provided on the side opposite to the exhaust gas introduction side in the turbine, and compressed air by the compressor is supplied to the air chamber. An air opening passage is provided in the air passage, and an on-off valve is provided in the air opening passage. The on-off valve is closed in a positive pressure on the air discharge side of the compressor and opened in a negative pressure on the compressor. Things.

[0010] In the turbocharger according to the second aspect of the present invention, the on-off valve is biased and supported to the open side by biasing means.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of a turbocharger according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a main part (part II in FIG. 1) showing an operating state of the supercharger when the engine is stopped and at a low speed. FIG. 3 is a cross-sectional view of a main part showing an operating state of the supercharger when the engine is running at a high speed.

As shown in FIG. 1, a supercharger 1 of the present embodiment
0, the casing 11 is configured such that the first casing 12 at the center, the second casing 13 on the turbine side, and the third casing 14 on the compressor side are integrally fastened by bolts. The rotating shaft 15 is the first casing 1
2 is rotatably supported by a thrust bearing 16 and radial bearings 17 and 18.
Are compacted, while the compressor 20 is compacted at multiple ends.

The turbine 19 has a large number of blades 19a on its outer periphery. The blades 19a are connected to the exhaust gas introduction passage 21 and the exhaust gas exhaust passage 2 of the second casing 13.
Inscribed in 2. Reference numeral 23 denotes a connection portion to which a branch pipe from an exhaust pipe (not shown) of the diesel engine is connected. On the other hand, the compressor 20 has a large number of blades 20 a on the outer peripheral portion, and the blades 20 a are inscribed in the intake air introduction passage 24 of the third casing 14, and the intake air introduction passage 24 passes through the compressor 20. The swirling chamber 25 is connected to a combustion chamber of the engine via an intake air supply passage (not shown). Reference numeral 26 denotes a filter which rectifies the intake air by passing the intake air before being taken into the intake air introduction passage 24.

Further, a lubricating oil supply passage 27 is formed in the first casing 12, and a base end of the lubricating oil supply passage 27 is connected to an oil pump of the engine, while a multi-end is formed of three branch passages. The thrust bearing 16 and the radial bearings 17, 18 are connected via 28, 29, 30 to supply lubricating oil to the bearings 16, 17, 18.

Further, a seal member 31 is attached to the end of the first casing 12 on the side of the turbine 19 so as to extend over the second casing 13, and the seal member 31 slides on the turbine 19 so that the exhaust gas is exhausted. Leakage is prevented. On the other hand, a seal member 32 is attached to an end of the first casing 12 on the compressor 20 side, and the seal member 32 slides against the compressor 20 to prevent leakage of intake air.

Further, the side opposite to the exhaust gas introduction side in the turbine 19, that is, the turbine 19 and the seal member 3
Air chamber 33 having a ring shape at a position defined by 1
The first casing 12 has an air passage 34 formed from the spiral chamber 25 on the compressor 20 side to the air chamber 33. An open-to-air passage 35 is connected to the air passage 34 at the end of the open-to-atmosphere passage 35 which opens on the side surface of the first casing 12. The vacuum breaker 36 is mounted.

That is, in the vacuum breaker 36, as shown in FIG. 2, a housing 37 is fixed to the first casing 12 so as to cover the opening end of the above-described open air passage 35. Inside, a stepped recess 38 communicating with the atmosphere opening passage 35 is formed, and a plurality of openings 39 opening from the recess 38 to the outside are formed. The housing 37 has a valve member 4
0 shaft part 41 is supported movably along the horizontal direction,
The recess 38 can be opened and closed by the valve member 40. A cover 42 is attached to the housing 37 so as to cover the shaft 41 of the valve member 40 projecting outward, and a compression spring 43 as urging means is provided between the shaft 41 and the cover 42. The compression spring 43 stretches the valve member 40 to bias and support the recess 38 toward the open side.

Therefore, as shown in FIG. 1, the exhaust gas from the diesel engine is supplied to the exhaust gas introduction passage 2 of the supercharger 10.
When the turbine 19 is guided to the turbine 19 through the exhaust gas 1, the turbine 19 is rotated by the gas flow of the exhaust gas, and the exhaust gas is discharged from the exhaust gas discharge passage 22. Then, the compressor 20 provided coaxially and integrally with the turbine 19 via the rotary shaft 15 rotates, and air is sucked into the suction air introduction passage 24 through the filter 26, and the compressor 20
As a result, the compressed air is compressed in the swirl chamber 25, and the compressed air is sent into the combustion chamber of the engine through the intake air supply passage, so that the output of the diesel engine can be increased.

[0020] Also, the high rotation speed of this diesel engine
During high-load operation, high-pressure exhaust gas acts on the turbine 19, and the turbine 19 is pressed toward the compressor 20. However, at this time, the compressor 20
Is sent from the spiral chamber 25 to the air passage 34 to be in a pressurized (positive pressure) state, and as shown in FIG. 3, the compressed air passes through the open air passage 35 to the concave portion 38 of the vacuum breaker 36. To move the valve member 40 against the urging force of the compression spring 43 to close the recess 38. Therefore, the compressed air does not leak and the air passage 3
4, the compressed air presses the turbine 19 in a direction opposite to that of the compressor 20, and the turbine 19 receiving the pressure of the exhaust gas can be pushed back and maintained at a fixed position. Therefore, the turbine 19 does not move to the compressor 20 side due to the pressure of the exhaust gas, and the leakage of the exhaust gas and the leakage of the lubricating oil due to the deformation of the seal member 31 and the bearings 16, 17 and 18 due to the axial stress of the rotating shaft 15. Can be prevented from being damaged.

Also, during idling operation of the diesel engine or low-speed / low-load operation of the diesel engine, the pressure of the exhaust gas acting on the turbine 19 is low, so that the turbine 19 also has a low speed, and the compressor 20 cannot compress the intake air. Instead, the inside of the spiral chamber 25 is in a negative pressure state due to the suction force from the combustion chamber side. At this time, since the negative pressure of the spiral chamber 25 acts on the air passage 34, as shown in FIG. 2, the concave portion 38 of the vacuum breaker 36 also has a negative pressure via the atmosphere opening passage 35, and the valve member 40 has a negative pressure. And the urging force of the compression spring 43 moves to open the recess 38. for that reason,
Outside air is introduced into the recess 38 from the opening 39 and the swirl chamber 25
Flow through the air passage 34 and the air chamber 3
The air in 3 is not sucked. Therefore, the air chamber 3
3 does not become negative pressure, and it is possible to prevent leakage or the like caused by suction of the lubricating oil supplied to the bearings 16, 17, and 18.

As described above, in the supercharger of the present embodiment, the ring shape is formed at a position defined by the seal member 31 and the turbine 19 located on the side opposite to the exhaust gas introduction side of the turbine 19. An air chamber 33 is formed, an air passage 34 is formed from the swirl chamber 25 on the compressor 20 side to the air chamber 33, and an air opening passage 35 that opens to the outside is connected to the air passage 34. Vacuum breaker 3 which opens and closes at the open end of compressor 35 in accordance with the pressure of the supplied air by compressor 20
6 is installed.

Therefore, when the diesel engine is operating at a high speed and a high load, the compressed air acts on the vacuum breaker 36 from the swirl chamber 25 through the air passage 34 and the atmosphere opening passage 35 on the compressor 20 side, and the valve member 40 38 is closed, the compressed air is supplied to the air chamber 33 without leaking, and the turbine 19 pressed by the exhaust gas can be pushed back to maintain the fixed position,
Exhaust gas leakage, lubricating oil leakage, bearings 16, 17, 18
Can be prevented from being damaged. On the other hand, at the time of idling operation or low-speed / low-load operation of the diesel engine, the compressor 20 does not operate and the swirl chamber 25 is in a negative pressure state due to the suction force from the combustion chamber side. Acting on the vacuum breaker 36 via the opening passage 35, the valve member 40 opens the concave portion 38, and the outside air flows from the concave portion 38 to the spiral chamber 25, and the air passage 34
The air chamber 33 does not become negative pressure through the
Leakage of lubricating oil from 17, 18 can be prevented.

Further, in the vacuum breaker 36, the valve member 40 is urged and supported by the compression spring 43 in the opening direction of the concave portion 38, so that oil and dust adhere to the sliding portion between the housing 37 and the shaft portion 41. Even if it does not hinder its movement,
Operability can be improved.

[0025]

As described above, according to the turbocharger of the first aspect of the present invention, the air chamber is provided on the side opposite to the exhaust gas introduction side in the turbine, and the compression by the compressor is performed. In addition to providing an air passage for guiding air to the air chamber, an air release passage is provided in the air passage,
An on-off valve that closes at the time of positive pressure on the air discharge side of the compressor and opens at the time of negative pressure is provided in the atmosphere opening passage. Therefore, when the engine is running at high speed, the compressed air of the compressor is opened and closed via the air passage and the atmosphere opening passage. Compressed air is supplied to the air chamber without leaking, and the turbine is maintained at a fixed position.On the other hand, when the engine is running at a low speed, the negative pressure of the combustion chamber causes the air passage and the atmosphere opening passage to be closed. Through the open / close valve, the outside air flows to the combustion chamber side, and the negative pressure does not act on the air chamber via the air passage. Can be prevented.

Further, according to the supercharger of the invention of claim 2,
Since the on-off valve is biased and supported to the open side by the biasing means, even if oil, dust, or the like adheres to the sliding portion of the on-off valve, the movement is not hindered, and the operability can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a supercharger according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part (a part II in FIG. 1) showing an operating state of the supercharger when the engine is stopped and at a low speed.

FIG. 3 is a sectional view of a main part showing an operating state of a supercharger when the engine is running at a high speed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Supercharger 11 Casing 15 Rotating shaft 19 Turbine 20 Compressor 21 Exhaust gas introduction path 22 Exhaust gas exhaust path 24 Intake air introduction path 25 Swirl chamber 31 Seal member 33 Air chamber 34 Air passage 35 Air opening passage 36 Vacuum breaker (open / close valve) 37) housing 38 recess 39 opening 40 valve member 43 compression spring (biasing means)

Claims (2)

[Claims] 1. A supercharger for compressing and feeding intake air by rotating a turbine by a gas flow of exhaust gas and rotating a compressor provided coaxially with the turbine, wherein the exhaust gas in the turbine is An air chamber is provided on the side opposite to the gas introduction side, an air passage for guiding compressed air by the compressor to the air chamber is provided, and an air release passage is provided in the air passage, and an air discharge side of the compressor is provided. A turbocharger characterized in that an on-off valve that closes at the time of positive pressure and opens at the time of negative pressure is provided in the atmosphere opening passage. 2. The supercharger according to claim 1, wherein the on-off valve is biased and supported to the open side by biasing means.