JP4821734B2 - Turbocharger cooling system - Google Patents

Description

  The present invention relates to a cooling device for a turbocharger.

Conventionally, various techniques for cooling the turbocharger have been developed. For example, Patent Document 1 describes a technique in which a cooling water passage is provided in a compressor housing of a turbocharger. Patent Document 2 describes a technique of providing a cooling water passage in a center housing of a turbocharger.
JP 2003-35153 A JP 2006-194135 A JP-A-10-252490 JP 2005-127307 A

  In an internal combustion engine having a turbocharger, blow-by gas generated in the internal combustion engine is introduced upstream of the compressor housing of the turbocharger in the intake passage of the internal combustion engine. Therefore, blow-by gas is contained in the intake air flowing into the compressor housing.

  When the temperature in the compressor housing rises as the supercharging pressure rises, the lubricating oil component in the blow-by gas contained in the intake air may carbonize. In this case, the carbonized lubricating oil component adheres to the inner wall surface of the compressor housing as a deposit. In particular, in the diffuser portion having a small intake passage cross-sectional area in the compressor housing, the intake air temperature is likely to rise, and thus deposits are easily generated.

  When the amount of deposit attached to the inner wall surface of the diffuser portion increases, the flow rate of the intake air passing through the diffuser portion decreases. As a result, there is a risk that the supercharging pressure will decrease, or that the turbocharger's rotational speed will increase excessively in order to increase the supercharging pressure, thereby promoting the deterioration of the turbocharger.

  The present invention has been made in view of the above problems, and provides a technique capable of suppressing the generation of deposits in the diffuser part by efficiently cooling the diffuser part in the compressor housing of the turbocharger. The purpose is to do.

  The present invention provides a compressor housing side heat medium passage through which a heat medium flows through the vicinity of a diffuser section in a compressor housing of a turbocharger, and a center housing side heat provided in the compressor housing side heat medium passage and the center housing of the turbocharger. Communicate with the media path. Then, the heat medium is caused to flow into the compressor housing side heat medium passage and out of the center housing side heat medium passage.

More specifically, the turbocharger cooling device according to the present invention is:
A cooling device for a turbocharger of an internal combustion engine,
A center housing side heat medium passage formed in the center housing of the turbocharger and through which the heat medium flows;
A compressor housing-side heat medium passage formed in the compressor housing of the turbocharger and through which the heat medium flows through the vicinity of the diffuser portion,
The center housing side heat medium passage and the compressor housing side heat medium passage communicate with each other;
The heat medium flows so as to flow into the compressor housing side heat medium passage and to flow out of the center housing side heat medium passage.

  According to the present invention, the cooler heat medium flows through the compressor housing side heat medium passage. Therefore, the diffuser part of the compressor housing can be efficiently cooled. As a result, the generation of deposits in the diffuser section can be suppressed.

  In the present invention, the heat medium may be caused to flow into the compressor housing side heat medium passage when the supercharging pressure is equal to or higher than a predetermined pressure.

  Here, the predetermined pressure may be a lower limit value of the supercharging pressure at which it can be determined that the temperature of the diffuser section increases as the amount of deposit generated in the diffuser section increases excessively.

  According to the above, it is possible to suppress an excessive increase in the amount of deposit generated in the diffuser section.

  In the present invention, when the temperature of the diffuser portion is lower than the temperature of the heat medium flowing into the compressor housing side heat medium passage, the flow of the heat medium into the compressor housing side heat medium passage may be prohibited.

  According to this, it can suppress that a diffuser part is heated by a heat medium.

  In the present invention, the compressor housing may further include an intake air passage formed separately from the compressor housing side heat medium passage and through which the intake air flows through the vicinity of the diffuser portion. In this case, the inlet of the intake flow passage is formed on the end surface on the intake inlet side of the compressor housing, and the outlet of the intake flow passage is formed on the inner wall surface upstream of the compressor wheel in the compressor housing.

  According to such a configuration, the outlet of the intake flow passage is positioned downstream of the inlet of the intake flow passage along the flow of intake air flowing into the compressor housing. Further, since the inlet of the intake flow passage is formed on the end surface on the intake inlet side of the compressor housing, the intake air is pushed into the intake flow passage by the dynamic pressure of the intake air flowing toward the compressor housing. Further, since the outlet of the intake flow passage is formed on the inner wall surface upstream of the compressor wheel in the compressor housing, the intake air is sucked out from the intake flow passage by the suction action of the intake air flowing toward the compressor wheel in the compressor housing. It is.

  Thus, according to the above, the intake air can easily flow through the intake flow passage. As a result, the diffuser portion can be further cooled not only by the heat medium flowing through the compressor housing side heat medium passage but also by the intake air flowing through the intake air flow passage.

  ADVANTAGE OF THE INVENTION According to this invention, the diffuser part in the compressor housing of a turbocharger can be cooled efficiently. As a result, the generation of deposits in the diffuser section can be suppressed.

  Hereinafter, specific embodiments of a cooling device for a turbocharger according to the present invention will be described with reference to the drawings.

<Example 1>
FIG. 1 is a diagram illustrating a schematic configuration of a turbocharger according to the present embodiment. The turbocharger 1 has a compressor housing 2, a center housing 3, and a turbine housing (not shown). The compressor housing 2 and the turbine housing are respectively provided in an intake passage 4 and an exhaust passage (not shown) of a diesel engine (not shown) for driving a vehicle. An intake pressure sensor 14 for detecting a supercharging pressure is provided downstream of the compressor housing 2 in the intake passage 4.

  A rotor shaft 7 is supported on the center housing 3 so as to be rotatable about its axis. A compressor wheel 6 in the compressor housing 2 is connected to one end of the rotor shaft 7, and a turbine wheel (not shown) in the turbine housing is connected to the other end of the rotor shaft 7.

  A purge passage 5 is connected to the intake passage 4, and blow-by gas generated in the diesel engine is introduced into the intake passage 4 through the purge passage 5. The compressor housing 2 is installed on the downstream side of the connection portion with the purge passage 5 in the intake passage 4.

  A center housing side cooling water passage 11 is formed in the center housing 3 so as to surround the rotor shaft 7. A compressor housing side cooling water passage 10 is formed in the vicinity of the diffuser portion 9 in the compressor housing 2. In the present embodiment, a recess is formed in the joint surface of the compressor housing 2 with the center housing 3, and when the compressor housing 2 and the center housing 3 are fitted, the compressor housing side cooling water passage 10 is formed by the recess. The Gaskets 16 are provided on the inner and outer sides of the compressor housing side cooling water passage 10 at the joint surface between the compressor housing 2 and the center housing 3.

  The center housing side cooling water passage 11 and the compressor housing side cooling water passage 10 communicate with each other. A cooling water circulation passage 12 is connected to each of the center housing side cooling water passage 11 and the compressor housing side cooling water passage 10. A radiator (not shown) is provided in the middle of the cooling water circulation passage 12. Then, the cooling water flows from the cooling water circulation passage 12 into the compressor housing side cooling water passage 10, and the cooling water flows through the compressor housing side cooling water passage 10 and the center housing side cooling water passage 11. 11 flows out to the cooling water circulation passage 12. That is, the cooling water flows in the order of the cooling water circulation passage 12 → the compressor housing side cooling water passage 10 → the center housing side cooling water passage 11 → the cooling water circulation passage 12. The compressor housing 2, particularly the diffuser portion 9 is cooled by the cooling water flowing through the compressor housing side cooling water passage 10. Further, the rotor shaft 7 is cooled by the cooling water flowing through the center housing side cooling water passage 11. In this embodiment, the cooling water corresponds to the heat medium according to the present invention.

The cooling water circulation passage 12 is provided with a cooling water control valve 13 that opens or closes the cooling water circulation passage 12. When the cooling water control valve 13 is opened, the cooling water circulation passage 12 is opened, and the cooling water flows into the compressor housing side cooling water passage 10. On the other hand, when the cooling water control valve 13 is closed, the cooling water circulation passage 12 is blocked and the inflow of cooling water to the compressor housing side cooling water passage 10 is prohibited. A temperature sensor 15 that detects the temperature of the cooling water is provided between the radiator in the cooling water circulation passage 12 and the cooling water passage 10 on the compressor housing side. The temperature sensor 15 causes the compressor housing side cooling water passage 1 to
The temperature of the cooling water flowing into 0 is detected.

  The diesel engine according to this embodiment is provided with an electronic control unit (ECU) 20 that controls the operation state of the diesel engine. An intake pressure sensor 14 and a temperature sensor 15 are electrically connected to the ECU 20. Output signals from these sensors are input to the ECU 20. In addition, the coolant control valve 13 is electrically connected to the ECU 20. The cooling water control valve 13 is controlled by the ECU 20.

  In this embodiment, blow-by gas is introduced into the intake air flowing through the intake passage 4 upstream of the compressor housing 2. Therefore, intake air containing blowby gas flows into the compressor housing 2. In this case, when the temperature in the compressor housing 2 increases as the supercharging pressure increases, the lubricating oil component in the blow-by gas contained in the intake air is carbonized, and the carbonized lubricating oil component serves as a deposit as the inner wall surface of the compressor housing 2. There is a risk of sticking to. Such deposits are particularly likely to be generated at the diffuser section 9 in the compressor housing 2.

  Here, according to the present embodiment, the cooling water first flows into the compressor housing side cooling water passage 10 from the cooling water circulation passage 12. Therefore, cooler cooling water flows through the compressor housing side cooling water passage 10. Therefore, the diffuser part 9 of the compressor housing 2 can be efficiently cooled. As a result, the generation of deposits in the diffuser unit 9 can be suppressed.

  Next, a first cooling water flow control routine according to the present embodiment will be described based on the flowchart shown in FIG. This routine is stored in advance in the ECU 20, and is repeatedly executed at predetermined intervals during operation of the diesel engine.

  In this routine, the ECU 20 first reads the supercharging pressure Pin detected by the intake pressure sensor 14 in S101.

  Next, the ECU 20 proceeds to S102 and determines whether or not the supercharging pressure Pin is equal to or higher than a predetermined pressure P0. Here, the predetermined pressure P0 is a lower limit value of the supercharging pressure at which it can be determined that the temperature of the diffuser unit 9 increases as the amount of deposit generation in the diffuser unit 9 increases excessively. If an affirmative determination is made in S102, the ECU 20 proceeds to S103, and if a negative determination is made, the ECU 20 once ends this routine.

  In S <b> 103, the ECU 20 opens the cooling water control valve 13 and causes the cooling water to flow into the compressor housing side cooling water passage 10. As a result, the cooling water circulates through the compressor housing side cooling water passage 10 and the center housing side cooling water passage 11. Thereafter, the ECU 20 once ends this routine.

  According to the routine described above, an excessive temperature rise in the diffuser unit 9 can be suppressed. As a result, it is possible to suppress an excessive increase in the amount of deposit generated in the diffuser unit 9.

  Next, a second cooling water flow control routine according to the present embodiment will be described based on the flowchart shown in FIG. This routine is stored in advance in the ECU 20, and is repeatedly executed at predetermined intervals during operation of the diesel engine.

  In this routine, the ECU 20 first reads the supercharging pressure Pin detected by the intake pressure sensor 14 in S201.

  Next, the ECU 20 calculates the temperature Tdi of the diffuser unit 9 based on the supercharging pressure Pin. In this embodiment, the relationship between the supercharging pressure Pin and the temperature Tdi of the diffuser unit 9 is obtained based on experiments and the like, and these relationships are stored in advance in the ECU 20 as a map.

  Next, the EUC 20 proceeds to S203 and determines whether or not the temperature Tdi of the diffuser unit 9 is lower than the temperature of the cooling water detected by the temperature sensor 15 (that is, the temperature of the cooling water flowing into the compressor housing side cooling water passage 10). Is determined. If an affirmative determination is made in S203, the ECU 20 proceeds to S204, and if a negative determination is made, the ECU 20 once ends this routine.

  In S <b> 204, the ECU 20 closes the coolant control valve 13 and prohibits the coolant from flowing into the compressor housing side coolant passage 10. Thereafter, the ECU 20 once terminates execution of this routine.

  According to the routine described above, when the temperature of the cooling water flowing through the cooling water circulation passage 12 is equal to or higher than the temperature of the diffuser section 9, the inflow of the cooling water into the compressor housing side cooling water passage 10 is prohibited. Therefore, it can suppress that the diffuser part 9 is heated with cooling water.

<Example 2>
FIG. 4 is a diagram illustrating a schematic configuration of the compressor housing of the turbocharger according to the present embodiment. In the present embodiment, in addition to the compressor housing side cooling water passage 10, an intake air passage 21 through which intake air flows through the vicinity of the diffuser portion 9 is formed in the compressor housing 2. Since other configurations in the configuration of the turbocharger according to the present embodiment are the same as those of the first embodiment, the same reference numerals are given to the same components and the description thereof is omitted.

  As shown in FIG. 4, in this embodiment, the inlet 21 a of the intake flow passage 21 is formed at the intake inlet side end face of the compressor housing 2, and the outlet 21 b of the intake flow passage 21 is upstream of the compressor wheel 6 in the compressor housing 2. It is formed on the inner wall surface on the side.

  In FIG. 4, arrows indicate the flow of intake air. As shown in FIG. 4, the intake air flows from the intake passage 4 through the inlet 21 a into the intake flow passage 21. Then, it flows out from the intake flow passage 21 through the outlet 21 b into the compressor housing 2, and the outflowed intake air merges with the intake air flowing from the intake inlet of the compressor housing 2 toward the compressor wheel 6.

  By providing the inlet 21 a and the outlet 21 b of the intake flow passage 21 at the positions as described above, the outlet 21 b is positioned downstream of the inlet 21 a along the flow of intake air flowing into the compressor housing 2. Further, since the inlet 21 a of the intake flow passage 21 is formed on the intake inlet side end face of the compressor housing 2, the intake air is pushed into the intake flow passage 21 by the dynamic pressure of the intake air flowing toward the compressor housing 2. Further, the outlet 21 b of the intake flow passage 21 is formed on the inner wall surface upstream of the compressor wheel 6 in the compressor housing 2, so that the intake flow passage is caused by the suction action of the intake air flowing toward the compressor wheel 6 in the compressor housing 2. The intake air is sucked out from the inside 21.

That is, by forming the intake flow passage 21 as in the present embodiment, intake air can flow more easily through the intake flow passage 21. As a result, the diffuser portion 9 can be further cooled not only by the cooling water flowing through the compressor housing side cooling water passage 10 but also by the intake air flowing through the intake flow passage 21.

  In the present embodiment, the first and second cooling water flow control according to the first embodiment can be applied.

1 is a diagram illustrating a schematic configuration of a turbocharger according to a first embodiment. 5 is a flowchart showing a routine of first cooling water flow control according to the first embodiment. 7 is a flowchart illustrating a routine for second cooling water flow control according to the first embodiment. FIG. 5 is a diagram illustrating a schematic configuration of a compressor housing of a turbocharger according to a second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Turbocharger 2 ... Turbine housing 3 ... Center housing 4 ... Intake passage 5 ... Purge passage 6 ... Compressor wheel 7 ... Rotor shaft 9 ... Diffuser part 10- -Compressor housing side cooling water passage 11-Center housing side cooling water passage 12-Cooling water circulation passage 13-Cooling water control valve 14-Intake pressure sensor 15-Temperature sensor 20-ECU
21 .. Intake flow passage 21a .. Inlet 22a .. Outlet

Claims (4)

A cooling device for a turbocharger of an internal combustion engine,
A center housing side heat medium passage formed in the center housing of the turbocharger and through which the heat medium flows;
A compressor housing-side heat medium passage formed in the compressor housing of the turbocharger and through which the heat medium flows through the vicinity of the diffuser portion,
A heat medium circulation passage provided outside the turbocharger is connected to each of the center housing side heat medium passage and the compressor housing side heat medium passage,
The center housing side heat medium passage and the compressor housing side heat medium passage communicate with each other;
The turbocharger cooling device, wherein the heat medium flows from the heat medium circulation passage to the compressor housing side heat medium passage and flows from the center housing side heat medium passage to the heat medium circulation passage .   The turbocharger cooling device according to claim 1, wherein when the supercharging pressure is equal to or higher than a predetermined pressure, a heat medium is caused to flow into the compressor housing side heat medium passage.   The inflow of the heat medium into the compressor housing side heat medium passage is prohibited when the temperature of the diffuser portion is lower than the temperature of the heat medium flowing into the compressor housing side heat medium passage. 2. The turbocharger cooling apparatus according to 2. The compressor housing further includes an intake air passage formed separately from the compressor housing side heat medium passage and through which the intake air flows through the vicinity of the diffuser portion,
The inlet of the intake flow passage is formed on an intake inlet side end face of the compressor housing, and the outlet of the intake flow passage is formed on an inner wall surface upstream of the compressor wheel in the compressor housing. The turbocharger cooling device according to any one of claims 1 to 3.

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