JP2017223170A - Supercharging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a supercharging system enabling reduction in the size of the system.SOLUTION: A supercharging system 19 includes an electric compressor 20 for driving compressor impellers by using a motor 30. The electric compressor 20 includes a first compressor 21 and a second compressor 22 that are disposed in series in the intake air flowing direction in an intake passage 11 of an internal combustion engine 10. The first compressor impeller 21A of the first compressor 21 and the second compressor impeller 22A of the second compressor 22 are connected to the common motor 30 via a first clutch 31 and a second clutch 32, respectively.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a supercharging system including an electric compressor that drives a compressor impeller by a motor.

  As a supercharging system for an internal combustion engine, an electric compressor that drives a compressor impeller by a motor, and a turbocharger that drives the compressor impeller by using exhaust energy received by a turbine provided in an exhaust passage are known. When an electric compressor is employed as a supercharging system for an internal combustion engine, it is difficult to obtain a necessary supercharging pressure when the engine operating state is in a high rotation range for the following reason.

  That is, in an electric compressor, the longer the compressor impeller with a larger diameter is adopted, the longer it takes for the rotation of the compressor impeller to reach a desired rotational speed after supplying electric power to the motor. For this reason, in order to realize a high response, it is necessary to employ a compressor impeller having a small diameter. However, the more the motor is rotated at a higher speed, the more complicated the control for driving the motor is. Therefore, there is a limit to realizing a high supercharging pressure by using a compressor impeller with a small diameter and rotating the motor at a high speed.

  In order to obtain a sufficient supercharging pressure even when the engine operating state is in a high rotation range, a turbocharger is employed in combination with an electric compressor as in the supercharging system described in Patent Document 1, for example. It is possible. By adopting such a configuration, the turbocharger can obtain a sufficient boost pressure in the high rotation range where the exhaust gas flow rate is high, and the weakness of the turbocharger that makes the response worse when the exhaust gas flow rate is low. Can be supplemented by.

JP2013-148062A

  By the way, the supercharging system described in Patent Document 1 includes two drive sources such as a motor that drives a compressor impeller in an electric compressor and a turbine that drives a compressor impeller in a turbocharger. That is, not only two compressors, an electric compressor and a turbocharger, are provided in the intake passage, but a turbocharger turbine is provided in the exhaust passage. For this reason, the system was large.

  The present invention has been made in view of such circumstances, and an object thereof is to suppress an increase in the size of the system while ensuring high response and sufficient supercharging in a high rotation range.

  The supercharging system for solving the said subject is provided with the electric compressor which drives a compressor impeller with a motor. The electric compressor includes a first compressor and a second compressor that are arranged in series in the intake flow direction in an intake passage connected to the internal combustion engine. A first compressor impeller in the first compressor is connected to the motor via a first clutch, and a second compressor impeller in the second compressor is connected to a motor common to the motor to which the first compressor impeller is connected. Connected through.

  In the above configuration, the first compressor impeller and the second compressor impeller can be selectively driven by separately controlling the first clutch and the second clutch. That is, the two first and second compressors arranged in series in the intake passage can be controlled separately, and a high response and a sufficient supercharging in a high rotation range can be ensured.

  On the other hand, in the above configuration, the first compressor impeller and the second compressor impeller are driven by a common motor. Therefore, the drive source required in the supercharging system can be reduced as compared with a configuration requiring two drive sources, such as a supercharging system including an electric compressor and a turbocharger. In addition, since it is not necessary to provide a turbine in the exhaust passage, constituent members in the exhaust system can be reduced. As a result, an increase in the size of the system can be suppressed.

The schematic diagram which shows one Embodiment of a supercharging system. The map used by the drive control in the supercharging system which concerns on the same embodiment. (A) is a schematic diagram showing the driving mode of the supercharging system in the low rotation range, (b) is a schematic diagram showing the driving mode of the supercharging system in the middle rotation range, and (c) is the supercharging system in the high rotation range. The schematic diagram which shows a drive mode. The schematic diagram which shows the supercharging system in another embodiment.

Hereinafter, an embodiment of a supercharging system will be described with reference to FIGS.
As shown in FIG. 1, a supercharging system 19 that can supply pressurized intake air to the internal combustion engine 10 is provided on the intake side of the internal combustion engine 10. The supercharging system 19 includes an intake passage 11 that is connected to the internal combustion engine 10 and guides intake air from outside to the inside of the internal combustion engine 10. The intake passage 11 is provided with an air cleaner 12 that removes dust and the like in the intake air.

  An electric compressor 20 for compressing intake air is provided downstream of the air cleaner 12 in the intake passage 11. The electric compressor 20 includes two compressors, that is, a first compressor 21 and a second compressor 22. Inside the first compressor 21, a first compressor impeller 21A is disposed. The first compressor impeller 21A rotates around the first rotation shaft 24, and compresses the intake air on the upstream side and supplies the compressed air to the downstream side. Inside the second compressor 22, a second compressor impeller 22A is disposed. The second compressor impeller 22A rotates about the second rotation shaft 25, and compresses the intake air on the upstream side and supplies the compressed air to the downstream side. The diameter (outer diameter) of the second compressor impeller 22A is larger than the diameter (outer diameter) of the first compressor impeller 21A.

  The first compressor 21 and the second compressor 22 in the electric compressor 20 are arranged in series in the intake flow direction in the intake passage 11. In this embodiment, the second compressor 22 is provided on the upstream side (air cleaner 12 side) in the intake flow direction, and the first compressor 21 is provided on the downstream side (internal combustion engine 10 side) in the intake flow direction.

  The electric compressor 20 includes an electric motor 30 for rotating the first compressor impeller 21A and the second compressor impeller 22A. The motor 30 has a main body 30a in which a coil, a magnet, and the like are incorporated, and a drive shaft 23 for outputting a rotational force to the outside. The drive shaft 23 is provided so as to penetrate the main body 30a, and both one end and the other end of the drive shaft 23 protrude outside the main body 30a. One end of the drive shaft 23 is connected to the first rotating shaft 24 of the first compressor 21 via the first clutch 31. The other end of the drive shaft 23 is connected to the second rotating shaft 25 of the second compressor 22 via the second clutch 32.

  The first clutch 31 can switch between transmission and disconnection of the driving force between the motor 30 and the first compressor impeller 21A, one of the clutch portions being the drive shaft 23 of the motor 30 and the other being the first compressor. 21 are connected to the first rotating shaft 24 respectively. When the first clutch 31 is in the connected state, the driving force is transmitted between the motor 30 and the first compressor impeller 21A. On the other hand, when the first clutch 31 is released, the driving force between the motor 30 and the first compressor impeller 21A is disconnected.

  The second clutch 32 can switch between transmission and disconnection of the driving force between the motor 30 and the second compressor impeller 22A. One of the clutch portions is the drive shaft 23 of the motor 30 and the other is the second compressor. The second rotation shafts 22 are respectively connected to the second rotation shaft 25. Similarly to the first clutch 31, the second clutch 32 transmits driving force between the motor 30 and the second compressor impeller 22 </ b> A when in the connected state, and when in the released state, The driving force is disconnected from the second compressor impeller 22A.

  The supercharging system 19 is connected to the intake passage 11 and is provided with a bypass passage 41 that bypasses the first compressor 21. The bypass passage 41 is connected from the portion between the first compressor 21 and the second compressor 22 in the intake passage 11 to the downstream portion of the intake air flow of the first compressor 21. In the bypass passage 41, a bypass valve 42 for adjusting the intake flow rate flowing through the bypass passage 41 is provided.

  The supercharging system 19 configured as described above is controlled by the control device 50. Specifically, the control device 50 controls the rotation speed of the motor 30 in the supercharging system 19, switching between the first clutch 31 and the second clutch 32, and the opening degree of the bypass valve 42. In addition, the control apparatus 50 is ECU (electronic control unit) of a vehicle, for example.

  As shown in FIG. 2, the control device 50 according to the present embodiment depends on the operating state of the internal combustion engine 10, more specifically, on the rotational speed (engine rotational speed) and load (engine load) of the internal combustion engine 10. The supercharging system 19 is controlled. Specifically, a region where the engine rotation speed is relatively low (low rotation region), a region where the engine rotation speed is relatively high (high rotation region), a low rotation region and a high rotation region, The supercharging system 19 is controlled separately for the region between the two (medium rotation region). Each engine speed range is the same as the engine speed range belonging to the middle engine speed range compared to the engine speed range belonging to the low engine speed range or the engine speed range belonging to the high engine speed range under the same engine load. Is a narrow relationship. Further, the control device 50 stores in advance in the storage unit of the control device 50 whether the internal combustion engine 10 belongs to one of the “low rotation region”, “medium rotation region”, or “high rotation region”. This is determined with reference to a map or an arithmetic expression. The solid line shown in FIG. 2 indicates the upper limit of the engine load that occurs in the internal combustion engine 10.

  Next, the operation and effect of the supercharging system 19 of the present embodiment will be described with reference to FIGS. 3A to 3C, the flow of intake air is indicated by arrows.

  As shown in FIG. 3A, when the operating state of the internal combustion engine 10 is in the low rotation range of FIG. 2, the first clutch 31 is brought into the connected state. Thereby, the driving force from the motor 30 is transmitted to the first compressor impeller 21 </ b> A, and the first compressor impeller 21 </ b> A rotates at a rotational speed corresponding to the rotational speed of the motor 30. On the other hand, the second clutch 32 is released. Thereby, since the driving force between the second compressor impeller 22A and the motor 30 is cut, the second compressor impeller 22A is not rotated by the driving force from the motor 30. Further, the bypass valve 42 is closed. By performing the drive control of the supercharging system 19 as described above, in the low speed range, the intake air flow upstream of the second compressor 22 in the intake passage 11, the second compressor 22, the first compressor 21, and the first intake passage 11. The intake air flows in the order downstream of the intake air flow of the compressor 21.

  According to the drive control of the supercharging system 19 in such a low rotational speed region, the first compressor 21 having a high response is driven by rotating the first compressor impeller 21A having a diameter smaller than that of the second compressor impeller 22A. Can do. Therefore, the supercharging pressure required in the low rotation range can be obtained by driving the first compressor 21. Further, in the low rotation range, the second compressor impeller 22A is not rotated by the driving force from the motor 30, so that unnecessary energy consumption of the motor 30 can be suppressed.

  As shown in FIG. 3B, when the operating state of the internal combustion engine 10 is in the middle rotation range of FIG. 2, both the first clutch 31 and the second clutch 32 are connected. Thereby, the driving force from the motor 30 is transmitted to both the first compressor impeller 21A and the second compressor impeller 22A. Further, the bypass valve 42 is closed. By performing the drive control of the supercharging system 19, the intake air flow upstream of the second compressor 22, the second compressor 22, the first compressor in the intake passage 11 in the middle rotation region as in the low rotation region. The intake air flows through the intake passage 11 in the order of the intake air flow downstream of the first compressor 21 in the compressor 21 and the intake passage 11.

  According to the drive control of the supercharging system 19 in the middle rotation range, the boost pressure obtained by rotating both the first compressor impeller 21A and the second compressor impeller 22A is lower than in the low rotation range. Will also increase.

  By the way, when the operating state of the internal combustion engine 10 shifts from the low rotation region to the middle rotation region, the second clutch 32 is changed from the released state to the connected state. At this time, the second clutch 32 is gradually changed from the released state to the connected state. Thereby, rotation of 2nd compressor impeller 22A can be started, suppressing rotation fall of 21 A of 1st compressor impellers.

  When the second clutch 32 is changed from the released state to the connected state in this way, the energy required by the motor 30 is increased compared to the low rotation range where only the first clutch 31 is in the connected state. . Therefore, when the operating state of the internal combustion engine 10 shifts from the low rotation range to the medium rotation range, the rotation reduction of the first compressor impeller 21A is suppressed by increasing the output of the motor 30. At this time, the rotation speed of the motor 30 is kept at the same level as the low rotation range.

  Further, in the middle rotation range, the rotation of the second compressor impeller 22A is performed with a view to shifting the operation state of the internal combustion engine 10 from the middle rotation range to the high rotation range. When the operating state of the internal combustion engine 10 shifts from the middle rotation range to the high rotation range in a state where the second compressor impeller 22A is rotated in advance in this way, the second compressor impeller 22A reaches a desired rotation speed from the shifted timing. It is possible to shorten the time required for the process.

  Here, as described above, when the engine load is the same, the engine rotation speed belonging to the middle rotation speed range is compared with the engine rotation speed speed range belonging to the low rotation speed range or the engine rotation speed range belonging to the high rotation speed range. The range is narrow. For this reason, the operation state of the internal combustion engine 10 does not stay long in the middle rotation range, but shifts to the low rotation range or the high rotation range. Depending on the time belonging to such a middle rotation range, the rotation speed of the second compressor impeller 22A may not reach the rotation speed according to the rotation speed of the motor 30. Even in such a case, according to the drive control of the supercharging system 19 in the middle rotation range, the first compressor impeller 21A can be rotated to obtain at least the same supercharging pressure as in the low rotation range. it can.

  As shown in FIG. 3 (c), when the operating state of the internal combustion engine 10 is in the high rotation range of FIG. 2, the first clutch 31 is released. Thereby, since the driving force between the first compressor impeller 21A and the motor 30 is cut, the first compressor impeller 21A is not rotated by the driving force from the motor 30. On the other hand, the second clutch 32 is brought into a connected state. Thereby, the driving force is transmitted from the motor 30 to the second compressor impeller 22A, and the second compressor impeller 22A rotates at a rotational speed corresponding to the rotational speed of the motor 30. Further, the bypass valve 42 is opened. By performing the drive control of the supercharging system 19 in this manner, in the high speed range, the intake air flow upstream of the second compressor 22 in the intake passage 11, the second compressor 22, the bypass passage 41, and the first compressor in the intake passage 11. The intake air flows in the order of the 21 intake air flow downstream.

  According to the drive control of the supercharging system 19 in such a high rotation range, the supercharging pressure required in the high rotation range is obtained by rotating the second compressor impeller 22A having a diameter larger than that of the first compressor impeller 21A. Can be obtained by driving the second compressor 22.

  Further, in the high rotation range, the first compressor impeller 21A is not rotated by the driving force from the motor 30, so that unnecessary energy consumption of the motor 30 can be suppressed.

  The passage around the first compressor impeller 21 </ b> A of the first compressor 21 is narrower than the passage around the second compressor impeller 22 </ b> A of the second compressor 22. For this reason, if intake air flows from the second compressor 22 to the first compressor 21, an amount of intake air corresponding to the passage in the first compressor 21 flows downstream of the intake air flow of the first compressor 21 in the intake passage 11. It becomes like this.

  In the present embodiment, the intake valve is caused to bypass the first compressor 21 by opening the bypass valve 42 in the high rotation range. As a result, the amount of intake air corresponding to the passage in the second compressor 22 flows downstream of the intake air flow of the first compressor 21 in the intake passage 11, so that the amount of intake air supplied to the internal combustion engine 10 can be increased. .

  Further, although the first clutch 31 is in a released state in the high rotation range, if the intake air is allowed to flow from the second compressor 22 to the first compressor 21, the first compressor impeller 21A may become an intake resistance. is there. In this embodiment, by setting the bypass valve 42 to the open state, intake air can be supplied to the internal combustion engine 10 while avoiding the intake resistance caused by the first compressor impeller 21A.

  Thus, in the above embodiment, the first compressor impeller 21A and the second compressor impeller 22A are driven by the common motor 30. On the other hand, by controlling the clutches 31 and 32, the first compressor impeller 21A and the second compressor impeller 22A can be selectively driven. For this reason, even if only one motor 30 is provided, the two compressors 21 and 22 arranged in series in the intake passage 11 can be controlled separately, and a high response and sufficient excess in the high rotation range can be achieved. Can be secured. That is, the driving source required for the supercharging system 19 can be reduced as compared with a configuration that requires two driving sources, such as a conventional supercharging system including an electric compressor and a turbocharger. In addition, since it is not necessary to provide a turbine in the exhaust passage, constituent members in the exhaust system can be reduced. Therefore, according to the said embodiment, the enlargement of the supercharging system 19 can be suppressed.

  By the way, as the supercharging system 19, for example, the intake passage 11 is branched into two, the first compressor 21 is provided in one of the branch passages, and the second compressor 22 is provided in the other branch passage. Conceivable. However, in the supercharging system 19 having such a configuration, intake air may flow from one of the compressors 21 and 22 to the other through a branch point in the intake passage 11. Therefore, it is necessary to provide an on-off valve or the like at a branch point in the intake passage 11 to suppress the intake air flow. In the supercharging system 19 in the present embodiment, since the compressors 21 and 22 are provided in series in the intake passage 11, there is no need for an on-off valve or the like for measures against the intake air flow, and the structure can be simplified. it can.

It should be noted that the above-described embodiment can be implemented with the following modifications.
-You may employ | adopt the structure of the supercharging system shown in FIG. As shown in FIG. 4, an electric compressor 70 provided in the supercharging system 69 includes a first compressor 71 having a first compressor impeller 71A therein and a shape having a larger diameter than the first compressor impeller 71A. And a second compressor 72 having a two-compressor impeller 72A therein. In the intake passage 11, the first compressor 71 is provided upstream of the second compressor 72 in the intake air flow. The intake passage 11 is provided with a bypass passage 91 that bypasses the first compressor 71. The bypass passage 91 is connected to the portion between the first compressor 71 and the second compressor 72 from the upstream portion of the intake air flow of the first compressor 71 in the intake passage 11. In the bypass passage 91, a bypass valve 92 for adjusting the intake flow rate in the bypass passage 91 is provided. Even in such a supercharging system 69, the clutches 31 and 32 and the bypass valve 92 can be controlled as in the above-described embodiment. That is, when the operating state of the internal combustion engine 10 is in the low rotation range, the first clutch 31 is in the connected state, the second clutch 32 is in the released state, and the bypass valve 92 is closed. When the operating state of the internal combustion engine 10 is in the middle rotation range, both the first clutch 31 and the second clutch 32 are connected, and the bypass valve 92 is closed. When the operating state of the internal combustion engine 10 is in the high rotation range, the first clutch 31 is released, the second clutch 32 is connected, and the bypass valve 92 is opened. By performing such control, the same operation and effect as the above-described embodiment can be obtained.

  If the output of the motor 30 is relatively low when the operating state of the internal combustion engine 10 is in the low rotation range, the rotation speed of the first compressor impeller 21A is also relatively low. For this reason, when the operating state of the internal combustion engine 10 shifts from the low rotation region to the middle rotation region, the second clutch 32 is temporarily changed without gradually changing the second clutch 32 from the released state to the connected state. Even when the engine is instantaneously switched from the released state to the connected state, the rotation of the first compressor impeller 21A is unlikely to decrease. For this reason, when the operating state of the internal combustion engine 10 shifts from the low rotation region to the middle rotation region, the second clutch 32 may be instantaneously switched from the released state to the connected state.

  Similarly, if the output of the motor 30 is relatively low when the operation state of the internal combustion engine 10 is in the low rotation range, the operation state of the internal combustion engine 10 is temporarily shifted from the low rotation range to the middle rotation range. Even if the output of the motor 30 is not changed, the rotation reduction of the first compressor impeller 21A hardly occurs. For this reason, the output of the motor 30 may not be changed when the operating state of the internal combustion engine 10 shifts from the low rotation range to the middle rotation range.

  A speed increaser may be provided between the clutches 31 and 32 and the compressor impellers 21A, 22A, 71A, and 72A. In such a form, when the clutches 31 and 32 are in the connected state, the compressor impellers 21A, 22A, 71A, and 72A can be rotated at a higher speed than the rotational speed corresponding to the output of the motor 30. The speed increaser is provided only in one of the first clutch 31 and the first compressor impellers 21A and 71A and between the second clutch 32 and the second compressor impellers 22A and 72A. You may make it provide in both. In the case where the speed increaser is provided only in one of the above, since the energy required by the motor 30 is increased, the compressor impellers 21A, 22A, 71A, 72A can be rotated at a desired rotational speed. To some extent, the output of the motor 30 needs to be increased. Further, as described above, when the operating state of the internal combustion engine 10 is in the middle rotation range, both the first compressor impellers 21A and 71A and the second compressor impellers 22A and 72A are rotated. In order to obtain a supercharging pressure in such a case, it is preferable that the first compressor impellers 21A and 71A have a higher rotation than the second compressor impellers 22A and 72A having a larger diameter than the first compressor impellers 21A and 71A. . Therefore, if a speed increaser is provided between the first clutch 31 and the first compressor impellers 21A and 71A, the second compressor impellers 22A and 72A can be rotated at a higher speed than the second compressor impellers 22A and 72A. 1 compressor impeller 21A, 71A can be rotated.

  -You may abbreviate | omit a middle rotation area from the control area of the supercharging systems 19 and 69. FIG. In this embodiment, the operating state of the internal combustion engine 10 is switched between two regions of the low rotation region and the high rotation region, and the control mode in the low rotation region and the high rotation region described above is changed according to the switching of the region. The supercharging systems 19 and 69 are controlled.

  The compressor impeller 21A and the compressor impeller 22A may have the same diameter. Further, the compressor impeller 71A and the compressor impeller 72A may have the same diameter. In the supercharging systems 19 and 69 including the electric compressors 20 and 70 of this form, the bypass passages 41 and 91 and the bypass valves 42 and 92 are omitted, and the middle rotation region is omitted from the control region. In the low rotation range, only one of the compressor impellers 21A and 71A and the compressor impellers 22A and 72A is rotated, while in the high rotation range, both the compressor impellers 21A and 71A and the compressor impellers 22A and 72A are rotated. Even with such a configuration, it is possible to ensure high response in the low rotation range and sufficient supercharging in the high rotation range. Moreover, in such a form, both the 1st clutches 31 and 32 will be in a connection state in a high rotation area. At this time, since the thrust force acting on the first compressor impellers 21A, 71A and the thrust force acting on the second compressor impellers 22A, 72A cancel each other, the compressor impellers 21A, 22A, 71A, The rotational loss of 72A can be reduced.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Intake passage, 19, 69 ... Supercharging system, 20, 70 ... Electric compressor, 21, 71 ... 1st compressor, 21A, 71A ... 1st compressor impeller, 22, 72 ... 2nd compressor, 22A, 72A ... second compressor impeller, 30 ... motor, 31 ... first clutch, 32 ... second clutch, 41,91 ... bypass passage, 42,92 ... bypass valve, 50 ... control device.

Claims (1)

A supercharging system including an electric compressor that drives a compressor impeller by a motor,
The electric compressor includes a first compressor and a second compressor arranged in series in an intake air flow direction in an intake passage connected to an internal combustion engine,
A first compressor impeller in the first compressor is connected to the motor via a first clutch, and a second compressor impeller in the second compressor is common to the motor to which the first compressor impeller is connected. A supercharging system connected to a motor via a second clutch.

Images