JP2012207583A - Centrifugal compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal compressor that can prevent a centrifugal compressor from being damaged by ice.SOLUTION: The compressor 11 includes: a movable vane 20 provided in a diffuser flow path 16; a freeze determination unit 60 for determining a possibility that the vane 20 is frozen; and a drive stopping unit 62 for stopping the drive of the vane 20 when the freeze determination unit 60 determines the possibility that the vane 20 is frozen, thereby preventing the centrifugal compressor from being damaged by ice.

Description

  The present invention relates to a centrifugal compressor.

  2. Description of the Related Art Conventionally, a centrifugal compressor that is provided between an impeller and a scroll and has diffuser blades (vanes) in a diffuser section that decelerate and pressurize fluid accelerated by the impeller is known. The vane is provided in the diffuser flow path of the diffuser section to optimize the compression efficiency. For example, Patent Document 1 describes an invention including a rotatable vane. Patent Document 2 describes an invention including a vane that can project into a diffuser flow path.

JP 2009-180110 A JP 2001-329996 A

  However, for example, when a centrifugal compressor is used in a low temperature environment, the vane may freeze. Ice removed from the vane can damage the centrifugal compressor. An object of this invention is to provide the centrifugal compressor which can suppress the failure | damage of the centrifugal compressor by ice in view of the said subject.

  According to the present invention, there is a possibility that the movable vane provided in the diffuser flow path, the freezing determination unit that determines the possibility that the vane is frozen, and the vane is frozen by the freezing determination unit. If it is determined, the centrifugal compressor includes a drive stop unit that stops the drive of the vane. According to the present invention, damage to the centrifugal compressor due to ice can be suppressed.

  In the above configuration, an air flow rate measurement unit that measures an air flow rate flowing into the diffuser flow path is provided, and when the air flow rate measured by the air flow rate measurement unit is greater than or equal to a threshold value, the drive stop unit is It can be set as the structure which cancels | releases a drive stop. According to this configuration, the breakage of the centrifugal compressor is suppressed, and the compression efficiency of the centrifugal compressor can be increased.

  In the above-described configuration, a temperature acquisition unit that acquires the temperature at the outlet of the centrifugal compressor is provided, and when the temperature acquired by the temperature acquisition unit is equal to or higher than a threshold value, the drive stop unit cancels the drive stop of the vane It can be set as the structure to do. According to this configuration, the breakage of the centrifugal compressor is suppressed, and the compression efficiency of the centrifugal compressor can be increased.

  The said structure WHEREIN: The said vane can be set as the structure which is a rotary vane which can be rotated so that a diffuser flow path may be opened or closed, or a projecting type vane which can protrude to a diffuser flow path.

  ADVANTAGE OF THE INVENTION According to this invention, the centrifugal compressor which can suppress the damage of the centrifugal compressor by ice can be provided.

FIG. 1 is a schematic view illustrating an engine system including a compressor according to the first embodiment. FIG. 2 is a schematic view illustrating the compressor according to the first embodiment. FIG. 3 is a front view illustrating a rotary vane. FIG. 4 is a functional block diagram illustrating the configuration of the ECU included in the compressor according to the first embodiment. FIG. 5 is a flowchart illustrating the control of the compressor according to the first embodiment. FIG. 6A and FIG. 6B are schematic views illustrating a retractable vane.

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

  FIG. 1 is a schematic view illustrating an engine system including a compressor according to the first embodiment. As shown in FIG. 1, the engine system 100 includes an ECU (Engine Control Unit) 10, a compressor 11 (centrifugal compressor), a turbine 30, an air flow meter 31, an intake air thermometer 32, a supercharging pressure sensor 33, a clock 34, an EGR. A valve 35, an EGR (Exhaust Gas Recirculation) cooler 36, an intake pressure sensor 37, an intercooler 38, an engine 40 (internal combustion engine), and a water temperature gauge 42 are provided.

  The compressor 11 and the turbine 30 are connected by a shaft 14. An impeller 13 of the compressor 11 and a turbine 30 which will be described later can rotate around the shaft 14. Thus, the engine system 100 is a system including a turbocharger.

  One end of a gas passage 50 and one end of a gas passage 51 are connected to the compressor 11. The other end of the gas passage 50 is connected to the outside of the vehicle on which the compressor 11 is mounted, for example. One end of a gas passage 52 and one end of a gas passage 53 are connected to the turbine 30. The other end of the gas passage 53 is connected to the outside of the vehicle on which the compressor 11 is mounted, for example. The engine 40 is connected to the other end of the gas passage 51 and the other end of the gas passage 52. One end of the gas passage 55 is connected to the gas passage 51. One end of the gas passage 54 is connected to the gas passage 52. The EGR cooler 36 is connected to the other end of the gas passage 55 and the other end of the gas passage 54.

  The compressor 11 compresses the air flowing from the gas passage 50 and supplies the compressed air to the engine 40 through the gas passage 51. The turbine 30 discharges the exhaust of the engine 40 flowing in through the gas passage 52 through the gas passage 53. Although illustration is omitted, the gas passage 50 may be provided with an air cleaner for purifying air, and the gas passage 53 may be provided with a catalyst for purifying exhaust gas. Part of the exhaust discharged from the engine 40 flows into the EGR cooler 36 through the gas passage 54. The EGR cooler 36 cools the inflowing exhaust gas (EGR gas) and discharges it to the gas passage 55. The EGR gas flows into the engine 40 through the gas passage 55. Thus, the engine system 100 is a system that uses the high-pressure EGR system. The engine system 100 may use, for example, a low pressure EGR system or may not use an EGR system.

  An air flow meter 31 (air flow rate measuring unit) provided in the gas passage 50 measures the flow rate (air flow rate) of air flowing into the compressor 11 through the gas passage 50. The intake thermometer 32 provided in the gas passage 50 measures the temperature (intake air temperature) of the air (intake air) flowing into the compressor 11. An intake pressure sensor 37 provided in the gas passage 50 measures the pressure (intake pressure) of the air flowing into the compressor 11. The EGR valve 35 provided in the gas passage 55 is a valve for adjusting the flow rate of EGR gas. The intercooler 38 provided in the gas passage 51 cools the air sent out by the compressor 11. The supercharging pressure sensor 33 provided in the gas passage 51 measures the pressure (supercharging pressure) of the gas sent from the compressor 11 to the engine 40. A water temperature gauge 42 provided in the engine 40 measures the temperature of the cooling water of the engine 40. The clock 34 measures time.

  The ECU 10 acquires the air flow rate measured by the air flow meter 31, the intake air temperature measured by the intake air thermometer 32, the intake pressure measured by the intake pressure sensor 37, and the supercharging pressure measured by the supercharging pressure sensor 33. To do. The ECU 10 can adjust the flow rate of the EGR gas by controlling the open / closed state of the EGR valve 35. Further, the ECU 10 can adjust the compression efficiency of the compressor 11 by controlling the vane 20 included in the compressor 11. Details will be described later. The ECU 10 acquires the temperature of the cooling water measured by the water temperature gauge 42 and the time measured by the clock 34. Thereby, ECU10 can acquire the time when the temperature of the cooling water measured with the water thermometer 42 continued. Next, the compressor 11 will be described.

  FIG. 2 is a schematic view illustrating the compressor according to the first embodiment. As shown in FIG. 2, the compressor 11 includes a compressor housing 12, an impeller 13, a vane 20, a diffuser plate 21, a rotating shaft 22, and an actuator 23.

  The compressor housing 12 forms a casing for the compressor 11. The compressor housing 12 includes an impeller accommodating portion 12a. An impeller 13 is accommodated in the impeller accommodating portion 12a. The impeller 13 is rotated by a shaft 14. As described above, the shaft 14 is connected to the turbine 30 shown in FIG.

  The fluid is sucked into the compressor housing 12 from the suction port 12b. The fluid is, for example, outside air. The sucked fluid flows toward the impeller 13 and is sent outward by the rotation of the impeller 13. A scroll portion 15 is provided outside the impeller 13. The fluid sent outward by the impeller 13 is supplied to, for example, an intake manifold of the engine 40 through the scroll unit 15. A diffuser channel 16 is provided between the impeller 13 and the scroll portion 15. The diffuser channel 16 is formed so that the shroud side wall 17 and the hub side wall 18 face each other, and is provided adjacent to the periphery of the impeller 13. The side wall of the diffuser plate 21 forms part of the hub side wall 18. The diffuser flow path 16 converts the kinetic energy of the fluid sent out by the impeller 13 into pressure. The vane 20 is provided on the diffuser plate 21 and is disposed in the diffuser flow path 16. Next, the vane 20 will be described.

  FIG. 3 is a front view illustrating a vane. In FIG. 3, the upper half of the diffuser plate 21 is shown, and the number of vanes 20 is an example and can be changed. As shown in FIG. 3, the plurality of vanes 20 are provided on the diffuser plate 21. As indicated by the arrows, the vane 20 is rotatable about the rotation shaft 22 so as to open and close the diffuser flow path 16. Of the rotational directions, O is the opening direction and C is the closing direction. For example, as indicated by a solid line, the vane 20 rotates in the opening direction at a high air flow rate. At this time, the gap between the vanes 20 is widened. The gap between the vanes 20 becomes a flow path through which the fluid passes. Thus, when the air flow rate is high, by increasing the cross-sectional area of the diffuser flow channel 16, it is possible to suppress the pressure loss due to the collision between the air and the vane 20 and to increase the compression efficiency of the compressor 11. As indicated by the dotted line, when the air flow rate is low, the vane 20 rotates in the closing direction. At this time, the gap between the vanes 20 is narrowed. As described above, when the air flow rate is low, the flow passage cross-sectional area of the diffuser flow passage 16 can be reduced, and the compression efficiency of the compressor 11 can be increased. As described above, the vane 20 is a rotary vane. In the compressor 11, the compression efficiency can be optimized by opening and closing the vanes 20 in accordance with the air flow rate. The actuator 23 shown in FIG. 2 is a motor or the like, for example, and drives the vane 20. The ECU 10 can adjust the open / close state of the vane 20 by controlling the actuator 23.

  However, the vane 20 may freeze. When the frozen vane 20 rotates, ice attached to the surface of the vane 20 may be peeled off from the vane 20. The peeled ice may fall through the diffuser flow path 16 and collide with, for example, the impeller 13 shown in FIG. The compressor 11 may be damaged by the collision with the ice peeled from the vane 20. In particular, the impeller 13 has a small thickness and may be formed of a low strength material such as aluminum. For this reason, there is a high possibility that the impeller 13 is damaged by collision with ice.

  The ice separated from the vane 20 receives a force from the fluid flowing into the compressor 11. When the force applied to the ice (fluid force) is large, the fluid may be discharged to the outside of the compressor 11, more specifically in the upstream direction of the impeller 13. In this case, the ice does not collide with the impeller 13. However, for example, during low load operation, the air flow rate and the supercharging pressure are small. Accordingly, the fluid force is reduced. As a result, the gravity applied to the ice becomes larger than the fluid force, and the possibility that the ice falls in the diffuser flow path 16 and collides with the impeller 13 or the like increases. Moreover, since the temperature of the compressor 11 is lower than that of the turbine 30, for example, the ice is not easily melted. If the ice is not released to the outside of the compressor 11 and does not melt, the compressor 11 may be damaged by the ice.

  Freezing of the vane 20 occurs when condensed water or the like mixed in the compressor 11 adheres to the vane 20 and freezes. Condensed water is, for example, water in which moisture contained in outside air or EGR gas flowing into the compressor 11 is condensed. Since the temperature of the compressor 11 is lowered in a cold region, particularly during cold start, the vane 20 is likely to be frozen.

  FIG. 4 is a functional block diagram illustrating the configuration of the ECU included in the compressor according to the first embodiment. As shown in FIG. 4, the ECU 10 functions as a freezing determination unit 60, a drive control unit 61, a drive stop unit 62, and a temperature acquisition unit 63. The freezing determination unit 60 determines whether the vane 20 may be frozen based on the temperature of the cooling water measured by the water thermometer 42 and the time during which the predetermined temperature measured by the clock 34 continues. . The determination will be described later. The drive control unit 61 can drive the vane 20 by controlling the actuator 23 based on the air flow rate measured by the air flow meter 31 and the supercharging pressure measured by the supercharging pressure sensor 33. The drive stop unit 62 is included in the drive control unit 61 and stops driving the vane 20 when it is determined that the vane 20 may be frozen. In the example of the rotary vane shown in FIG. 3, the drive control unit 61 adjusts the rotation of the vane 20, and the drive stop unit 62 stops the rotation of the vane 20. The temperature acquisition unit 63 acquires the intake air temperature measured by the intake thermometer 32, the supercharging pressure measured by the supercharging pressure sensor 33, and the intake pressure measured by the intake pressure sensor 37. The temperature acquisition unit 63 can estimate the temperature (outlet temperature) T on the outlet side of the compressor 11 based on the intake pressure, the supercharging pressure, and the intake air temperature. The outlet temperature of the compressor 11 is, for example, the temperature at the connection point between the compressor 11 and the gas passage 51.

  Next, control of the compressor 11 according to the first embodiment will be described. FIG. 5 is a flowchart illustrating the control of the compressor according to the first embodiment.

  As shown in FIG. 5, the freezing determination unit 60 first determines whether or not there is a possibility that the vane 20 is frozen (step S10). In the case of No, that is, when it is determined that there is no possibility of the vane 20 being frozen, the control is finished. At this time, the drive control unit 61 can drive the vane 20 by controlling the actuator 23. In other words, the vane 20 can rotate.

  In the case of Yes, that is, when it is determined that the vane 20 may be frozen, the drive stopping unit 62 stops driving the vane 20 (step S11). Specifically, the drive stop unit 62 controls the actuator 23 so as not to rotate the vane 20. At this time, the vane 20 does not rotate. After step S11, the drive stop unit 62 determines whether the air flow rate F measured by the air flow meter 31 is equal to or greater than the air flow rate threshold value F0 (step S12). In the case of Yes, the drive stop part 62 cancels the drive stop of the vane 20 (step S14).

  In the case of No, the drive stop unit 62 determines whether the outlet temperature T estimated by the temperature acquisition unit 63 is equal to or higher than the temperature threshold T0 (step S13). In the case of Yes, the drive stop part 62 cancels the drive stop of the vane 20 (step S14). If no, control returns to step S12. At this time, the stop of driving of the vane 20 is not released. In other words, the driving of the vane 20 is stopped until either condition of F ≧ F0 or T ≧ T0 is satisfied. After step S14, the control ends.

  The compressor 11 according to the first embodiment includes a movable vane 20, a freezing determination unit 60, and a drive stopping unit 62 that stops driving the vane 20 when it is determined that the vane 20 may be frozen. And comprising. As shown in step S11 of FIG. 5, the drive stopping unit 62 stops driving the vane 20, so that the ice is prevented from peeling off from the vane 20 and the ice is also prevented from colliding with the impeller 13 or the like. The Therefore, it is suppressed that the compressor 11 is damaged by ice.

  The case where there is a possibility of freezing includes not only the case where the vane 20 is actually frozen, but also the case where freezing is likely to occur even if the vane 20 is not actually frozen. According to the first embodiment, when there is a possibility of freezing, the drive stop unit 62 stops driving the vane 20, so that the compressor 11 can be prevented from being damaged by ice.

  As shown in step S12 of FIG. 5, when the air flow rate F is equal to or greater than the threshold value F0, the fluid force is greater than the gravity applied to the ice. Therefore, the fall of the ice peeled from the vane 20 is suppressed. Further, as shown in step S13 of FIG. 5, when the outlet temperature T of the compressor 11 is higher than the threshold value T0, it is considered that the ice melts and the fall of the ice onto the impeller 13 or the like is suppressed. Thus, in the case of at least one of F ≧ F0 or T ≧ T0, damage to the compressor 11 due to ice is suppressed. For this reason, the drive stop unit 62 releases the drive stop of the vane 20. At this time, the drive control unit 61 can drive the vane 20. As a result, breakage of the compressor 11 due to ice can be suppressed, and the compression efficiency can be increased by driving the vanes 20. Note that at least one of steps S12 and S13 in FIG. 5 may be performed. However, both steps S12 and S13 are preferably performed in order to suppress breakage of the compressor 11 and increase the compression efficiency with higher accuracy.

  Instead of the air flow rate F, for example, the rotational speed of the turbine 30 shown in FIG. 1 may be used as an index for canceling the drive stop. Specifically, when the rotation speed of the turbine 30 is greater than a predetermined value, it may be determined that the fluid force is large, and the drive stop unit 62 may cancel the drive stop. As shown in FIG. 4, the temperature acquisition unit 63 estimates the outlet temperature T based on the intake air temperature, the intake air pressure, and the supercharging pressure. In addition to this, for example, a thermometer may be provided near the outlet of the compressor 11, and the temperature acquisition unit 63 may acquire the outlet temperature T measured by the thermometer.

  Next, the determination of the possibility of freezing will be described in detail. The water temperature gauge 42 measures the temperature of the cooling water between the stop and start of the engine 40, for example, at regular intervals. In this manner, the water temperature gauge 42 can measure the temperature a plurality of times and acquire the water temperature history from the stop to the start of the engine 40. The clock 34 can measure the time during which the temperature continues for each of a plurality of temperatures measured by the water temperature gauge 42 from the stop to the start. The freezing determination unit 60 determines freezing using temperature and time. A specific example will be described with reference to the table.

表１に示すように、凍結判定部６０は、水温計４２により測定された冷却水の温度Ｔ１ａ、Ｔ２ａ、Ｔ１ｂ、Ｔ２ｂ等を取得する。温度のうち、Ｔ１ａ及びＴ２ａ等は、例えば水の融点である２７３．１５Ｋ以下の温度であり、Ｔ１ｂ及びＴ２ｂ等は、例えば２７３．１５Ｋ以上の温度である。なお、２７３．１５Ｋ以下の温度を凍結温度、２７３．１５Ｋ以上の温度を融解温度とする。時間ｔ１ａは温度Ｔ１ａが継続した時間であり、時間ｔ２ａは温度Ｔ２ａが継続した時間である。時間ｔ１ｂは温度Ｔ１ｂが継続した時間であり、時間ｔ２ｂは温度Ｔ２ｂが継続した時間である。表１では省略した温度についても、継続した時間が測定される。 Table 1 is an example of a data table created by the freezing determination unit 60. In Table 1, the temperature is described from T1a to T2b, and the time is described from t1a to t2b, but the numbers of temperatures and times are examples. As indicated by black dots in the table, temperatures other than T1a to T2b and times other than t1a to t2b may be measured.

As shown in Table 1, the freezing determination unit 60 acquires the temperature T1a, T2a, T1b, T2b, etc. of the cooling water measured by the water thermometer 42. Among the temperatures, T1a and T2a are temperatures of 273.15K or lower, which is the melting point of water, for example, and T1b and T2b are temperatures of 273.15K or higher, for example. A temperature of 273.15K or lower is defined as a freezing temperature, and a temperature of 273.15K or higher is defined as a melting temperature. The time t1a is the time that the temperature T1a continues, and the time t2a is the time that the temperature T2a continues. The time t1b is the time that the temperature T1b continues, and the time t2b is the time that the temperature T2b continues. Even for the temperature omitted in Table 1, the continuous time is measured.

  The freezing determination unit 60 calculates, for each temperature, the product of the temperature and the time during which the temperature has continued. In the example of Table 1, the freezing determination unit 60 calculates T1a × t1a and the like. Furthermore, the freezing determination unit 60 calculates the sum A of products of the freezing temperature and the time during which the freezing temperature has continued. Moreover, the freezing determination part 60 calculates the sum B of the product of melting temperature and the time when melting temperature continued. In the example of Table 1, A = T1a × t1a + T2a × t2a +... And B = T1b × t1b + T2b × t2b +. The freezing determination unit 60 compares A and B and determines that the vane 20 may be frozen if A is larger than B. That is, the freezing determination unit 60 determines Yes in step S10 of FIG. On the other hand, when B is larger than A, the freezing determination unit 60 determines that there is no possibility that the vane 20 is frozen. That is, the freezing determination unit 60 determines No in step S10 of FIG.

  The freezing determination unit 60 can determine the possibility of freezing based on the temperature measured by the water thermometer 42 and the time measured by the clock 34. Specifically, as shown in Table 1, the freezing determination unit 60 calculates the product of the total A of the freezing temperature and the time during which the freezing temperature has continued, the product of the melting temperature and the time during which the melting temperature has continued. Compare the total B. For this reason, it becomes possible to determine the possibility of freezing with high accuracy. In particular, the freezing determination unit 60 can determine the freezing based on the temperature history from the stop to the start of the engine 40. For this reason, the breakage of the compressor 11 can be effectively suppressed at the time of cold start or the like where the possibility that the vane 20 is frozen increases.

  Example 2 is an example in which a retractable vane 20 is used. FIG. 6A and FIG. 6B are schematic views illustrating a retractable vane. 6A and 6B, the vicinity of the diffuser flow path 16 of the compressor 11 is enlarged. The configurations shown in FIGS. 1 and 2 other than the portions shown in FIGS. 6A and 6B are common to the second embodiment.

  As shown in FIGS. 6A and 6B, the projecting and retracting type vane 20 can project into the diffuser flow path 16 and can enter the hub side wall 18 through a slit 18 a provided in the hub side wall 18. It is. The drive control unit 61 controls the actuator 23 to drive the vane 20 so as to protrude and retract, thereby adjusting the amount of protrusion of the vane 20. As shown in FIG. 6A, for example, when the air flow rate is low, the vane 20 protrudes into the diffuser flow path 16 and abuts against the shroud side wall 17, for example. As shown in FIG. 6B, for example, when the air flow rate is high, the vane 20 is immersed in the hub side wall 18. Thereby, the compression efficiency of the compressor 11 can be improved according to the air flow rate. As the actuator 23, for example, a diaphragm type or solenoid type actuator or the like can be used.

  The control of the compressor according to the second embodiment is the same as that shown in FIG. When the freezing determination unit 60 determines that the vane 20 may be frozen, the drive stopping unit 62 stops driving the vane 20 (step S11). At this time, the vane 20 does not protrude or immerse. Therefore, it is suppressed that the compressor 11 is damaged by ice.

  In the protrusion-type vane 20, for example, by completely immersing the vane 20 in the hub side wall 18, freezing of the vane 20 can be suppressed and damage to the compressor 11 due to ice can be suppressed. However, when the vane 20 is immersed, the compression efficiency may decrease. In particular, when the air flow rate is low, the compression efficiency may be greatly reduced. On the other hand, in the second embodiment, since the drive stop unit 62 stops driving the vane 20, for example, the vane 20 may be stopped while protruding into the diffuser flow path 16. Therefore, high compression efficiency can be obtained even at a low air flow rate. As described in the first and second embodiments, the vane 20 may be either a rotary type or a projecting type, and may be a movable vane.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

10 ECU
DESCRIPTION OF SYMBOLS 11 Compressor 16 Diffuser flow path 20 Vane 23 Actuator 31 Air flow meter 33 Supercharging pressure sensor 34 Clock 40 Engine 42 Water temperature gauge 60 Freezing determination part 61 Drive control part 62 Drive stop part 63 Temperature acquisition part

Claims (4)

A movable vane provided in the diffuser flow path;
A freezing determination unit for determining the possibility that the vane is frozen;
A centrifugal compressor comprising: a drive stop unit that stops driving of the vane when the freezing determination unit determines that the vane may be frozen. An air flow rate measuring unit for measuring the air flow rate flowing into the diffuser flow path;
2. The centrifugal compressor according to claim 1, wherein when the air flow rate measured by the air flow rate measurement unit is equal to or greater than a threshold value, the drive stop unit releases the drive stop of the vane. A temperature acquisition unit for acquiring the temperature at the outlet of the centrifugal compressor;
3. The centrifugal compressor according to claim 1, wherein when the temperature acquired by the temperature acquisition unit is equal to or higher than a threshold value, the drive stop unit releases the drive stop of the vane. The centrifugal vane according to any one of claims 1 to 3, wherein the vane is a rotary vane that is rotatable so as to open and close the diffuser flow path, or a projecting vane that can protrude into the diffuser flow path. Compressor.

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