JP2018025122A - Pressure adjustment mechanism in turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure adjustment mechanism in a turbocharger which properly adjusts a pressure in an oil catch tank of the turbocharger without causing leakage of a blow-by gas when an engine is stopped to properly prevent leakage of a lubrication oil to an exhaust pipe and an air intake duct.SOLUTION: A pressure adjustment mechanism in a turbocharger includes: a turbocharger 10 including a bearing housing 40 for housing a shaft 13 and a bearing 14 which connect a compressor wheel 12 with a turbine wheel 11, and an oil catch tank 16 which recovers and stores a lubrication oil O; and pressure adjustment passages 41 which allow communication between an internal space A of the oil catch tank 16 and a scroll chamber 31 of a compressor housing 30. The pressure adjustment passages 41 are formed as ventilation passages which respectively open to the internal space A of the oil catch tank 16 and the interior of the scroll chamber 31 and formed in the compressor housing 30 and the bearing housing 40.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pressure adjustment mechanism in a turbocharger.

  In a turbocharger 10 (see FIGS. 5 and 6) mounted on a vehicle, a shaft 13 having a turbine wheel 11 and a compressor wheel 12 connected to both ends rotates at a high speed. It is necessary to supply O and lubricate (see, for example, Patent Documents 1 and 2). Therefore, for example, the lubricating oil O sucked up from the oil pan 2 of the engine 1 by an oil pump (not shown) is supplied to the inside of the turbocharger 10 from above the turbocharger 10 through the supply path 3 to lubricate the shaft 13 and the bearing 14. Configured as follows.

  The lubricating oil O supplied to the shaft 13 and the bearing 14 etc. flows downward through the flow path 15 inside the turbocharger 10. At that time, if the turbocharger 10 is above the oil pan 2 of the engine 1, the lubricating oil O flowing down in the turbocharger 10 can be returned to the oil pan 2 by being naturally dropped as it is.

  However, when the lubricating oil O cannot be returned to the oil pan 2 due to a natural fall, as in the case where the turbocharger 10 is below the oil pan 2 of the engine 1, the lubricating oil that has flowed down in the turbocharger 10 O cannot be returned to the oil pan 2 by natural fall.

  Therefore, for example, an oil catch tank 16 is provided below the turbocharger 10, and the lubricating oil O that has flowed down is collected and stored in the oil catch tank 16. The lubricating oil O in the oil catch tank 16 may be sucked up by a discharge pump (scavenge pump) 17 and forcibly discharged from the oil catch tank 16 and returned to the engine 1 through the discharge path 18. is there. In this case, the lubricating oil O returns to the oil pan 2 through the engine 1.

  By the way, when the engine 1 is activated and the vehicle travels and the oil catch tank 16 vibrates, the lubricating oil O in the oil catch tank 16 undulates, or the lubricating oil O in the oil catch tank 16 is driven by the acceleration of the vehicle. In some cases, the lubricating oil O in the oil catch tank 16 may contain air bubbles because it moves back and forth and right and left.

  Then, in order to accurately discharge the lubricating oil O containing bubbles, undulating, and biased forward, backward, left and right from the oil catch tank 16, it is necessary to use a discharge pump 17 having a high discharge capacity. Become. Therefore, the discharge capacity of the discharge pump 17 is higher than the capacity of the oil pump that sucks the lubricating oil O from the oil pan 2 of the engine 1 and supplies the lubricating oil O into the turbocharger 10 via the supply path 3. While the engine 10 is operating, that is, while the engine 1 is operating, the oil catch tank 16 has a negative pressure.

  When the engine 1 is stopped in this state, both the oil pump and the discharge pump 17 are stopped. However, since the oil catch tank 16 is at a negative pressure, the lubricating oil O remaining in the supply path 3 is reduced. It is drawn into the oil catch tank 16 side. Therefore, the amount of the lubricating oil O exceeds the storage capacity of the oil catch tank 16 (that is, overflows), the lubricating oil O accumulates in the flow path 15 in the turbocharger 10, and the shaft 13, the bearing 14, etc. As the oil is submerged, the lubricating oil O leaks from the bearing seal portion to the exhaust pipe 4 and the intake duct 5.

  Therefore, conventionally, as shown in FIG. 5, for example, the cylinder head, the crankcase, and the like of the engine 1 and the oil catch tank 16 are communicated with each other through the pressure adjustment path 19. In some cases, the blow-by gas in the engine 1 is supplied to the oil catch tank 16 to set the pressure in the oil catch tank 16 to atmospheric pressure.

  If the pressure is balanced between the oil catch tank 16 side and the lubricating oil O supply path 3 side when the engine is stopped in this way, the negative pressure in the oil catch tank 16 is supplied as described above. It is possible to prevent a problem that the lubricating oil O in the passage 3 is drawn into the oil catch tank 16 side.

JP 2007-309257 A JP 2010-196502 A

  However, in the cylinder head or crankcase of the engine 1, the lubricating oil O is in the form of a mist or has an oil pool, so it is necessary to attach the pressure adjustment path 19 to a high position of the engine 1. Thus, when the turbocharger 10 is below the oil pan 2 of the engine 1, the pressure adjusting path 19 that communicates them becomes longer vertically.

  Then, the longer the pressure adjustment path 19 is, the higher the possibility of being damaged, and the damage of the pressure adjustment path 19 may cause problems such as leakage of blow-by gas. Further, exhausting or leaking blowby gas into the atmosphere is strictly regulated both in Japan and Europe, and when the above-described conventional configuration is adopted, leakage of blowby gas from the pressure adjustment passage 19 is prevented. It is necessary to newly provide a device for detection.

  The present invention has been made in view of the above problems, and without adjusting the pressure in the oil catch tank of the turbocharger when the engine is stopped without causing leakage of blow-by gas, An object of the present invention is to provide a pressure adjusting mechanism in a turbocharger that can accurately prevent leakage into an intake duct.

In order to solve the above problem, the invention according to claim 1 is a pressure adjustment mechanism in a turbocharger,
A compressor housing that houses the compressor wheel;
A turbine housing that houses a turbine wheel;
A bearing housing that houses a shaft and a bearing connecting the compressor wheel and the turbine wheel;
An oil catch tank that collects and stores at least the lubricating oil supplied to the bearing;
A turbocharger with
A pressure adjusting path communicating the internal space of the oil catch tank and the scroll chamber of the compressor housing;
With
The pressure adjusting passage is opened as an air passage formed in the compressor housing and the bearing housing, respectively, and opens toward the inner space and the scroll chamber.

  The invention according to claim 2 is a pressure adjusting mechanism in the turbocharger according to claim 1, wherein a valve for adjusting a flow rate of air flowing through the pressure adjusting path when the engine is operating is provided in the pressure adjusting path. Alternatively, a valve for closing the pressure adjusting path is provided.

  According to a third aspect of the present invention, in the pressure adjusting mechanism in the turbocharger according to the first or second aspect, the pressure adjusting path is located at a position in the scroll chamber where the pressure is increased when the turbocharger is operated. An opening is provided.

  According to the pressure adjusting mechanism in the turbocharger of the present invention, the pressure in the oil catch tank of the turbocharger is accurately adjusted when the engine is stopped without causing the blow-by gas to leak to the exhaust pipe or intake duct of the lubricating oil. It is possible to prevent the leakage of the water accurately.

It is the schematic showing the structure of parts, such as a turbocharger and an engine, in which the pressure adjustment mechanism in the turbocharger which concerns on this embodiment was integrated. It is a schematic sectional drawing showing the structure of the pressure adjustment mechanism in the turbocharger which concerns on this embodiment. It is a schematic sectional drawing showing the valve provided in the modified example and pressure adjustment path of the pressure adjustment mechanism in the turbocharger which concerns on this embodiment. It is a schematic sectional drawing which follows the XX line of FIG. It is the schematic showing the structure of parts, such as a turbocharger and an engine, in which the pressure adjustment mechanism in the conventional turbocharger was incorporated. It is a schematic sectional drawing of the turbocharger in which the pressure adjustment mechanism in the conventional turbocharger was integrated.

  Embodiments of a pressure adjusting mechanism in a turbocharger according to the present invention will be described below with reference to the drawings. In the following, the case where the engine 1 is a horizontally opposed type as shown in FIG. 1 to be described later will be described. However, the present invention can also be applied to an in-line type or V type engine.

[Constitution]
FIG. 1 is a schematic diagram showing a configuration of a turbocharger, an engine, or the like in which a pressure adjusting mechanism in the turbocharger according to the present embodiment is incorporated, and FIG. 2 is a pressure in the turbocharger according to the present embodiment. It is a schematic sectional drawing showing the structure of an adjustment mechanism.

  As shown in FIG. 1, the air taken into the intake pipe 6 is supercharged by the turbocharger 10, cooled by the intercooler 7, and then supplied to the engine 1. Although not shown in FIG. 1, if the engine 1 is a gasoline engine, fuel (gasoline) is injected into the intake port or directly into the cylinder. Further, if the engine 1 is a diesel engine, fuel (light oil) is injected into the cylinder. The exhaust gas exhausted from the engine 1 passes through the turbocharger 10 and the exhaust pipe 4 and is purified by a catalyst (not shown) and then exhausted.

  As shown in FIGS. 1 and 2, also in this embodiment, the lubricating oil O sucked up from the oil pan 2 of the engine 1 by an oil pump (not shown) passes through the supply path 3 from above the turbocharger 10. It comes to be supplied. The supplied lubricating oil O passes through the flow path 15 in the turbocharger 10 (that is, in a bearing housing 40 described later) and lubricates the shaft 13 and the bearing 14.

  As will be described later, also in this embodiment, the turbocharger 10 includes the oil catch tank 16, and the lubricating oil O that lubricates the shaft 13, the bearing 14, and the like as described above flows down the flow path 15. Then, it is recovered and stored in the oil catch tank 16. A discharge path 18 is provided for communicating the engine 1 with the oil catch tank 16 of the turbocharger 10. The lubricating oil O stored in the oil catch tank 16 of the turbocharger 10 is sucked up by the discharge pump 17. The oil is forcibly discharged from the oil catch tank 16, returned to the engine 1 through the discharge path 18, and returned to the oil pan 2.

  Note that the discharge capacity of the discharge pump 17 is higher than the capacity of the oil pump to suck up the lubricating oil O from the oil pan 2 of the engine 1 and supply it into the turbocharger 10 via the supply path 3. The point that the oil catch tank 16 becomes negative pressure during operation of the engine 10, that is, during operation of the engine 1, is the same as in the conventional case described above in this embodiment.

  However, in the present embodiment, unlike the conventional case, there is no pressure adjustment path 19 (see FIG. 5) for communicating the cylinder head, crankcase, etc. of the engine 1 and the oil catch tank 16 of the turbocharger 10. .

  On the other hand, in this embodiment, as shown in FIG. 2, the turbocharger 10 includes a turbine housing 20 that houses the turbine wheel 11, a compressor housing 30 that houses the compressor wheel 12, and the turbine wheel 11 and the compressor wheel 12. A shaft 13 to be coupled and a bearing housing 40 for housing the bearing 14 are provided. The turbine housing 20, the bearing housing 40, and the compressor housing 30 are connected to each other.

  As described above, the bearing housing 40 is provided with the flow path 15 for supplying the lubricating oil O supplied via the supply path 3 to the shaft 14, the bearing 14, and the like. It opens below the housing 40. An oil catch tank 15 is disposed below the bearing housing 40, and the lubricating oil O flowing out of the flow path 15 of the bearing housing 40 flows down to the oil catch tank 16 and is collected and stored. It has become.

  The compressor housing 30 is provided with a spiral scroll chamber 31 around the compressor wheel 12. When the turbine wheel 11 is driven by the exhaust gas exhausted from the engine 1, the compressor wheel 12 rotates integrally therewith, sucks and compresses the air in the intake duct 5, and discharges it to the scroll chamber 31. To the intercooler 7 (see FIG. 1).

  In the present embodiment, the turbocharger 10 is provided with a pressure adjustment path 41 that communicates the internal space A of the oil catch tank 16 and the scroll chamber 31 of the compressor housing 30.

  That is, the pressure adjustment path 41 has an opening 41A that opens toward the internal space A of the oil catch tank 16, and an opening 41B that opens toward the scroll chamber 31 of the compressor housing 30. The pressure adjustment path 41 is connected to a passage formed in the wall surface of the compressor housing 30 and a passage formed in the wall surface of the bearing housing 40 at a connection portion between the compressor housing 30 and the bearing housing 40. And formed as a single tubular air passage connecting the openings 41A and 41B.

  2 shows a case where the pressure adjusting path 41 is formed by being drilled in the wall surface of the compressor housing 30 or the bearing housing 40. For example, as shown in FIG. It is also possible to constitute a part of 41 in the flow path 15 of the bearing housing 40.

[Action]
Next, the operation of the pressure adjustment mechanism in the turbocharger 10 according to this embodiment will be described.

  In the present embodiment, the discharge capacity of the discharge pump 17 (see FIG. 1) is greater than the capacity of the oil pump to suck up the lubricating oil O from the oil pan 2 of the engine 1 and supply the lubricating oil O into the turbocharger 10 via the supply path 3. Therefore, the oil catch tank 16 has a negative pressure during operation of the engine 1, that is, during operation of the turbocharger 10.

  When the engine 1 is stopped in this state, as shown in FIG. 2, the air in the scroll chamber 31 of the compressor housing 30 is oiled via the pressure adjustment path 41 due to the negative pressure in the oil catch tank 16. It flows into the catch tank 16. Therefore, the pressure in the oil catch tank 16 quickly becomes atmospheric pressure.

  On the other hand, when the engine 1 is stopped, if the crankcase or the cylinder head of the engine 1 (see FIG. 1) has a negative pressure, the engine 1 is connected via a passage (not shown) connecting the crankcase of the engine 1 and the intake pipe 6. Since air flows into the crankcase or cylinder head of 1, the inside of the crankcase or cylinder head of the engine 1 quickly becomes atmospheric pressure.

  Therefore, the pressure (atmospheric pressure) applied from the crankcase of the engine 1 and the pressure (atmospheric pressure) applied from the oil catch tank 16 of the turbocharger 10 to the lubricating oil O remaining in the supply passage 3 are the same. Become. Therefore, the lubricating oil O remaining in the supply path 3 is not drawn into the oil catch tank 16 side of the turbocharger 10. Further, even if the lubricating oil O remaining in the supply path 3 is drawn into the oil catch tank 16, the amount can be suppressed very slightly.

  Therefore, in this embodiment, after the engine is stopped, the lubricating oil O remaining in the supply passage 3 flows into the oil catch tank 16 and the oil catch tank 16 overflows, and the lubricating oil O causes the shaft 13 of the turbocharger 10 or the like. It is possible to accurately prevent the occurrence of a situation in which the bearing 14 or the like is immersed in oil or the lubricating oil O leaks from the seal portion to the exhaust pipe 4 or the intake duct 5.

[effect]
As described above, according to the pressure adjustment mechanism in the turbocharger according to the present embodiment, in order to increase the pressure in the oil catch tank 16 of the turbocharger 10 when the engine is stopped, it is possible to use blow-by gas as in the past. Instead, the air in the scroll chamber 31 of the compressor housing 30 is used. Therefore, it is possible to accurately prevent the occurrence of problems such as conventional leakage of blow-by gas into the atmosphere.

  In the present embodiment, as described above, the pressure adjusting passage 41 for sending the air in the scroll chamber 31 of the compressor housing 30 to the oil catch tank 16 is formed in the compressor housing 30 and the bearing housing 40. , That is, not exposed to the outside of the turbocharger 10. Therefore, it is not necessary to newly provide a device or the like for detecting leakage of blow-by gas from the pressure adjustment path 41.

  Also in this embodiment, while the engine 1 is operating, the oil catch tank 16 of the turbocharger 10 has a negative pressure. When the engine 1 is stopped in this state, the negative pressure in the oil catch tank 16 The air in the scroll chamber 31 of the compressor housing 30 flows into the oil catch tank 16 through the pressure adjustment path 41. Therefore, the pressure in the oil catch tank 16 quickly becomes atmospheric pressure.

  As described above, according to the pressure adjustment mechanism in the turbocharger according to the present embodiment, the pressure in the oil catch tank 16 of the turbocharger 10 is accurately adjusted when the engine is stopped, so that the pressure quickly becomes atmospheric pressure. 3, even if the lubricating oil O remaining in the turbocharger 10 is not drawn into the oil catch tank 16 side or the lubricating oil O remaining in the supply path 3 is drawn into the oil catch tank 16, It becomes possible to suppress the amount very slightly. Therefore, it is possible to accurately prevent the oil catch tank 16 from overflowing and the lubricating oil O from leaking into the exhaust pipe 4 or the intake duct 5.

  Further, in the pressure adjusting mechanism in the turbocharger according to the present embodiment, the structure is thus compact, and a device for detecting leakage of blow-by gas from the pressure adjusting path 41 as described above is newly provided. Since it is not necessary, the number of parts can be reduced. Therefore, there is a merit that it is possible to reduce the weight of the engine 1 and to suppress an increase in cost.

  In the present invention, the turbocharger 10 includes an oil catch tank 16, and the lubricating oil O collected in the oil catch tank 16 is forcibly discharged by a discharge pump 17 (see FIG. 1). However, the present invention is not necessarily limited to the case where the turbocharger 10 is provided below the oil pan 2 of the engine 1.

  In the present embodiment, the oil pressure adjusting passage 41 is provided as described above, so that the oil catch tank 16 and the scroll chamber 31 of the compressor housing 30 communicate with each other. Therefore, during operation of the turbocharger 10, that is, during operation of the engine 1, the air compressed by the compressor wheel 12 enters a state where not only the intercooler 7 side but also part of it flows into the oil catch tank 16. The pressure in the oil catch tank 16 becomes higher than when the pressure adjustment path 41 is not provided.

  During operation of the engine 1, the pressure in the turbine housing 20 of the turbocharger 10 is higher than the pressure in the oil catch tank 16 due to the gas pressure of the exhaust gas, so that the exhaust gas in the turbine housing 20 passes through the seal portion. In some cases, the oil may flow into the oil catch tank 16. However, in the present embodiment, as described above, air flows from the scroll chamber 31 of the compressor housing 30 through the pressure adjustment path 41 into the oil catch tank 16 and the pressure in the oil catch tank 16 increases. There is an advantage that exhaust gas hardly flows into the oil catch tank 16 from the turbine housing 20.

[Modification]
However, as described above, when a part of the air in the scroll chamber 31 of the compressor housing 30 flows into the oil catch tank 16 through the pressure adjustment path 41, the compression sent from the turbocharger 10 to the intercooler 7 correspondingly. The amount of air released is reduced. Therefore, as shown in FIG. 3, the pressure adjustment path 41 is provided with a valve 42 for adjusting the flow rate of air flowing through the pressure adjustment path 41 or a valve 42 for closing the pressure adjustment path 41 when the engine is operated. It can be configured as follows.

  If comprised in this way, while adjusting the flow volume of the air which flows through the pressure adjustment path 41 with the valve 42 at the time of engine operation, for example, while sending as much compressed air as possible to the intercooler 7 from the turbocharger 10, while the compressor housing 30 A part of the air in the scroll chamber 31 is caused to flow into the oil catch tank 16 to increase the pressure in the oil catch tank 16, thereby creating a state in which the exhaust gas hardly flows from the turbine housing 20.

  Further, for example, when the engine 1 is operating, if the exhaust gas does not flow into the oil catch tank 16 from the turbine housing 20 or if it flows only to the extent that there is no problem, the valve 42 is closed during engine operation. By closing the pressure adjustment path 41, the compressed air from the turbocharger 10 to the intercooler 7 can be sent without leakage.

  In this case, the valve 42 is provided in any part of the pressure adjustment path 41, and can be provided, for example, in the opening 41B to the scroll chamber 31 as shown in FIG. It is also possible to provide the connecting portion with the bearing housing 40, the opening 41A to the oil catch tank 16, or the like. For example, the valve 42 may be configured by an electromagnetic valve, and the opening and closing of the valve 42 may be controlled by an ECU (Electric Control Unit) (not shown).

  On the other hand, the pressure adjusting mechanism in the turbocharger according to the present embodiment adjusts the pressure in the oil catch tank 16 by sending air from the scroll chamber 31 of the compressor housing 30 into the oil catch tank 16 as described above. It is. If air is sent to the oil catch tank 16 from the place where the pressure in the scroll chamber 31 is as high as possible, the air can be sent accurately from the scroll chamber 31 to the oil catch tank 16 when the engine is stopped. Become.

  Therefore, as shown in FIG. 4, among the scroll chambers 31 of the compressor housing 30, the position B in the scroll chamber 31 where the pressure is highest when the turbocharger 10 is operating is determined in advance, and the opening of the pressure adjusting path 41 is located at that position. It is possible to provide the portion 41B.

  With this configuration, it is possible to reliably send air into the oil catch tank 16 from the scroll chamber 31 of the compressor housing 30 at least when the engine is stopped, and the pressure in the oil catch tank 16 can be adjusted accurately. It becomes possible.

  Needless to say, the present invention is not limited to the above-described embodiment and the like, and can be appropriately changed without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 Turbocharger 11 Turbine wheel 12 Compressor wheel 13 Shaft 14 Bearing 16 Oil catch tank 20 Turbine housing 30 Compressor housing 31 Scroll chamber 40 Bearing housing 41 Pressure adjustment path 41B Opening 42 Valve A Inner space B In the scroll chamber where the pressure becomes highest Position O Lubricant

Claims (3)

A compressor housing that houses the compressor wheel;
A turbine housing that houses a turbine wheel;
A bearing housing that houses a shaft and a bearing connecting the compressor wheel and the turbine wheel;
An oil catch tank that collects and stores at least the lubricating oil supplied to the bearing;
A turbocharger with
A pressure adjusting path communicating the internal space of the oil catch tank and the scroll chamber of the compressor housing;
With
The pressure adjusting passage is open to the inner space and the scroll chamber, and is formed as a vent passage formed in the compressor housing and the bearing housing. Adjustment mechanism.   The valve for adjusting the flow rate of the air flowing through the pressure adjustment path or the valve for closing the pressure adjustment path when the engine is operated is provided in the pressure adjustment path. The pressure adjustment mechanism in the turbocharger according to 1.   The pressure in the turbocharger according to claim 1 or 2, wherein the pressure adjusting path is provided with an opening at a position in the scroll chamber where the pressure is highest when the turbocharger is in operation. Adjustment mechanism.

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