JP2010053788A - Sequential turbo system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce cost and save space in a sequential turbo system. <P>SOLUTION: A rotary valve 15 is used as a flow rate control valve for exhaust of an internal combustion engine 10 supplied to a turbine 4B of a primary turbocharger 4 and a turbine 5B of a secondary turbocharger 5. A flow rate control of exhaust to first and second ports 16, 17 and a wastegate port 18 as well as a changeover of a turbocharger to be used are performed according to a rotation opening of the rotary valve 15. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sequential turbo system in which a rotary valve is used as a flow control valve for exhaust gas of an internal combustion engine supplied to first and second turbochargers.

  Generally, the sequential turbo system includes a parallel sequential turbo system and a series sequential turbo system.

  In the parallel sequential turbo system, a primary turbocharger and a secondary turbocharger are arranged in parallel, and control for switching between the single turbo mode and the twin turbo mode is performed for the primary turbocharger and the secondary turbocharger.

  In a series sequential turbo system, a high-pressure stage turbocharger and a low-pressure stage turbocharger having different maximum capacities are arranged in series, and the high-pressure stage turbocharger and the low-pressure stage turbocharger can be properly used. Yes.

  Typical examples of the parallel sequential turbo system include those proposed in Patent Documents 1 and 2.

  The parallel sequential turbo system proposed in Patent Document 1 uses a variable nozzle type turbocharger that operates independently in the engine low-speed rotation region, and increases the supercharging efficiency in the engine low-speed rotation region by adjusting the opening of the variable nozzle. When switching from the single turbo mode to the twin turbo mode, the variable nozzle is once throttled to prevent a sudden drop in the engine back pressure and the boost pressure.

  In addition, the parallel sequential turbo system proposed in Patent Document 2 controls the switching between the single turbo mode and the twin turbo mode for the primary turbocharger and the secondary turbocharger arranged in parallel in the intake passage and the exhaust passage. When performing, the target supercharging pressure in the single turbo mode and the target supercharging pressure in the twin turbo mode are calculated based on the operating state, and the mode switching is determined based on these target supercharging pressures. The time required for the determination can be shortened, and the occurrence of torque shock is suppressed by appropriately determining the switching.

  On the other hand, typical examples of the series sequential turbo system include those proposed in Patent Documents 3 to 5.

  The series sequential turbo system proposed in Patent Document 3 bypasses at least one of the turbine of the high-pressure stage turbocharger and the turbine of the low-pressure stage turbocharger, and flows through the bypass passage provided in the exhaust passage. An exhaust bypass valve that adjusts the flow rate of the exhaust gas, and the movable vane opening of the high-pressure stage turbocharger, the opening degree of the movable vane of the low-pressure stage turbocharger, and the exhaust so as to obtain a target supercharging pressure Each opening degree of the bypass valve is controlled.

  Further, the series sequential turbo system proposed in Patent Document 4 is configured to directly send a pressurized medium without providing an intercooler between two adjacent stage compressors.

Furthermore, the series sequential turbo system proposed in Patent Document 5 is provided with a bypass passage in the exhaust passage for supplying exhaust gas discharged from the high-pressure turbine to the exhaust purification device by bypassing the low-pressure turbine. The bypass passage is formed in a straight line from the outlet of the high-pressure stage turbine to the inlet of the exhaust purification device.
JP 2005-155356 A JP 2008-128129 A JP 2005-315163 A JP 2005-23903 A JP 2007-263033 A

  By the way, in a general sequential turbo system, there is no valve for switching the gas flow distribution in three or more directions, so a valve for switching the operating state of the turbocharger, a waste gate and an exhaust throttle are installed independently. ing. As a result, the situation is not only high in cost but also unable to save space.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a sequential turbo system capable of realizing cost reduction and space saving.

  In order to achieve the above object, a sequential turbo system according to the present invention is a sequential turbo system in which a rotary valve is used as a flow control valve for exhaust gas of an internal combustion engine supplied to first and second turbochargers. The rotary valve includes a cylindrical body, first, second, and third gate chambers that are formed so as to penetrate the body in the axial direction, and first, second, and second end surfaces of the body. A rotating body supported rotatably around an axis on a control surface in which the gate chamber of 3 is opened, and the first gate chamber is connected to a first port connected to the first turbocharger, The second gate chamber is connected to a second port connected to the second turbocharger, and the third gate chamber is connected to a waste gate port connected to a catalyst. And the first, second, and third gate chambers are arranged in this order along a rotation direction in which the rotating body opens each opening of the first, second, and third gate chambers. The exhaust gas flow rate control to the first and second ports and the waste gate port, and the used turbocharger are switched in accordance with the rotational opening of the rotating body.

  According to the above configuration, the flow rate control of the exhaust gas to the first and second ports and the waste gate port and the switching of the used turbocharger are performed according to the rotational opening of the rotary body of the rotary valve. The cost and space saving of the turbo system can be realized.

  By the way, if the rotational opening degree of the rotary body of the rotary valve is suddenly increased, the supercharging pressure will drop. Therefore, the flow control of the exhaust gas to the first and second ports and the waste gate port and the switching of the turbo used are required. When this is done, it is necessary to gradually increase the rotational opening of the rotating body so that the run-up can be achieved.

  Therefore, in the sequential turbo system, the first, second, and third gate chambers have a shape in which a change in cross-sectional area is moderated.

  In the sequential turbo system, the driving source of the rotating body is a motor.

  According to the present invention, cost reduction and space saving of a sequential turbo system can be realized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First embodiment]
<Overall configuration>
FIG. 1 is a diagram showing a simplified configuration of a sequential turbo system according to a first embodiment of the present invention.

  Referring to FIG. 1, a sequential turbo system 1 according to the present embodiment is a parallel sequential turbo system, and mainly includes an air cleaner 2, an intake passage 3, a primary turbocharger 4, a secondary turbocharger 5, and an intake air switching valve 6. , Intake bypass passage 7, intake bypass valve 8, intercooler 9, internal combustion engine (hereinafter also referred to as “engine”) 10, exhaust passage 11, EGR passage 12, EGR valve 13, EGR cooler 14, and rotary valve 15 and an ECU (electronic control unit) 30 shown in FIG. In the present system 1, the primary turbocharger 4 and the secondary turbocharger 5 are arranged in parallel.

  The air cleaner 2 purifies air (intake air) acquired from the outside and supplies it to the intake passage 3.

  The intake passage 3 is branched into two systems of a first intake passage portion 3A and a second intake passage portion 3B on the way and connected to an intercooler 9, and the third intake air of one system from the intercooler 9 is connected. The passage portion 3C is connected to the internal combustion engine 10.

  A compressor 4A of the primary turbocharger 4 is disposed in the first intake passage portion 3A, while a compressor 5A of the secondary turbocharger 5 is disposed in the second intake passage portion 3B.

  The compressor 4A of the primary turbocharger 4 compresses intake air that passes through the first intake passage 3, while the compressor 5A of the secondary turbocharger 5 compresses intake air that passes through the second intake passage portion 3B.

  An intake switching valve 6 is provided in the second intake passage 3. The intake air switching valve 6 is controlled to be opened and closed by a control signal supplied from the ECU 30, and is configured to be able to adjust the flow rate of the intake air passing through the second intake passage portion 3B. For example, by opening and closing the intake air switching valve 6, it is possible to switch the flow / blocking of the intake air in the second intake passage portion 3B.

  Further, an intake bypass passage 7 is provided in the second intake passage portion 3B. One end of the intake bypass passage 7 is connected to the intake passage 3 before branching into the two systems, and the other end is connected to the second intake passage between the compressor 5A of the secondary turbocharger 5 and the intake air switching valve 6. It is connected to the part 3B.

  An intake bypass valve 8 is provided in the intake bypass passage 7. The intake bypass valve 8 is a reed valve, and is configured to open when the differential pressure in the intake bypass passage 7 on the upstream side and the downstream side across the intake bypass valve 8 exceeds a predetermined value. Yes.

  The internal combustion engine 10 is a four-cylinder engine, and generates power by burning an air-fuel mixture of intake air and fuel supplied from the third intake passage portion 3C (intake passage 3). The internal combustion engine 10 is constituted by, for example, a gasoline engine or a diesel engine. The exhaust gas generated by the combustion in the internal combustion engine 10 is discharged to the exhaust passage 11. The internal combustion engine 10 is not limited to being configured with four cylinders.

  An EGR passage 12 is provided in the exhaust passage 11. The EGR passage 12 has one end connected to the exhaust passage 11 and the other end connected to the third intake passage portion 3C.

  The EGR passage 12 is a passage for returning exhaust gas (EGR gas) to the intake system. Therefore, the EGR passage 12 is provided with an EGR cooler 14 and an EGR valve 13.

  The EGR cooler 14 is a device that cools the EGR gas. On the other hand, the EGR valve 13 is a valve that adjusts the flow rate of the EGR gas that passes through the EGR passage 12, in other words, a valve that adjusts the amount of EGR gas recirculated to the intake system (that is, adjusts the EGR rate). The opening degree of the EGR valve 13 is controlled by a control signal supplied from the ECU 30.

  The exhaust passage 11 is branched into two systems, a first exhaust passage portion 11A and a second exhaust passage portion 11B. The turbine 4B of the primary turbocharger 4 is disposed in the first exhaust passage portion 11A, while the turbine 5B of the secondary turbocharger 5 is disposed in the second exhaust passage portion 11B.

  The turbine 4B of the primary turbocharger 4 is rotated by the exhaust gas passing through the first exhaust passage portion 11A, while the turbine 5B of the secondary turbocharger 5 is rotated by the exhaust gas passing through the second exhaust passage portion 11B. Is done. Such rotational torque of the turbines 4A and 5B is transmitted to the compressor 4A in the primary turbocharger 4 and the compressor 5A in the secondary turbocharger 5 to rotate, whereby the intake air is compressed (that is, supercharged). )

  A rotary valve 15 is provided at a branch portion where the exhaust passage 11 branches into the first exhaust passage portion 11A and the second exhaust passage portion 11B. The rotary valve 15 functions as a flow control valve for the exhaust gas of the internal combustion engine 10 supplied to the turbine 4B of the primary turbocharger 4 and the turbine 5B of the secondary turbocharger 5, and rotates the rotating body 26 described later. Depending on the angle (hereinafter referred to as “rotational opening”), the first port 16 connected to the turbine 4B of the primary turbocharger 4 via the first exhaust passage portion 11A and the second exhaust passage portion 11B The exhaust gas flow rate is controlled to the second port 17 connected to the turbine 5B of the secondary turbocharger 5 through the waste gate port 18 connected to the catalyst through the communication passage 19 and the used turbocharger is switched. .

<Rotary valve>
FIG. 2 is a plan view showing the configuration of the rotary valve.

  Referring to FIG. 2, the rotary valve 15 includes a cylindrical body 20, first, second and third gate chambers 21, 22, 23 formed so as to penetrate the body 20 in the axial direction. And a rotating body 26 rotatably supported around an axis 25 on a control surface 24 which is an upper end surface of the body 20 and opens the first, second and third gate chambers 21, 22, and 23. Yes.

  The first gate chamber 21 is connected to the first port 16 connected to the turbine 4B of the primary turbocharger 4, and the second gate chamber 22 is connected to the second port 17 connected to the secondary turbocharger 5, The third gate chamber 23 is connected to a waste gate port 18 connected to the catalyst. The first, second and third gate chambers 21, 22, and 23 are arranged in the rotational direction in which the rotating body 26 opens the respective openings of the first, second and third gate chambers 21, 22, and 23 (this embodiment). Are arranged adjacently in this order along the clockwise direction).

  The openings of the first, second, and third gate chambers 21, 22, and 23 are substantially fan-shaped and concentric with the body 20. The opening areas of the first and second gate chambers 21 and 22 are substantially the same, and the opening area of the third gate chamber 23 is smaller than the opening areas of the first and second gate chambers 21 and 22. Is set. The opening forming regions of the first, second, and third gate chambers 21, 22, and 23 are set in a range of 180 degrees with the axis 25 as the center.

  The rotating body 26 is a semicircular plate-like member so that the openings of the first, second and third gate chambers 21, 22, and 23 can be fully closed and fully opened. The driving source of the rotating body 26 is a stepping motor 37 (see FIG. 3) whose output shaft is coupled to the shaft 25. The driving of the stepping motor 37 is controlled by a control signal supplied from the ECU 30.

<Electrical configuration>
FIG. 3 is a diagram showing an electrical configuration of the sequential turbo system.

  The sequential turbo system 1 includes the ECU 30 as described above. The ECU 30 includes a CPU, ROM, RAM, backup RAM, and the like. The CPU governs the control center of the ECU 30, and executes arithmetic processing based on various control programs and maps stored in the ROM. The ROM stores various control programs and maps that are referred to when the various control programs are executed. Further, the RAM is a memory for temporarily storing calculation results in the CPU and data input from sensors 31, 32, 33, and 34 described later, and the backup RAM is stored when the internal combustion engine 10 is stopped. This is a non-volatile memory for storing data to be stored.

  The ECU 30 is supplied with detection signals from an engine speed sensor 31, an accelerator opening sensor 32, a gear position sensor 33, and an intake pressure sensor (air flow meter) 34. Based on these detection signals, the ECU 30 The drive of the switching valve 6, the EGR valve 13, and the rotary valve 15 is controlled.

  In particular, the ECU 30 opens and closes the intake air switching valve 6 by controlling an actuator 36 driven by a VSV (vacuum switching valve) 35. Further, the ECU 30 adjusts the rotational opening degree of the rotary body 26 of the rotary valve 15 by controlling the driving of the stepping motor 37 to which the output shaft of the shaft 25 of the rotary valve 15 described above is coupled.

<Map>
FIG. 4 is a diagram showing the configuration of the mode switching map of the sequential turbo system.

  Referring to FIG. 4, when the behavior state of engine 10 is in a region (1) defined by first switching line 41, the mode is a cold turbo bypass mode and an exhaust throttle mode. Here, the “exhaust throttle mode” is a mode in which the exhaust gas passage is throttled to increase the back pressure, thereby facilitating the introduction of EGR, or early catalyst warm-up.

  When the behavior state of the engine 10 is in the region (2) defined by the first switching line 41 and the second switching line 42, the mode is set to the single turbo mode.

  When the behavior state of the engine 10 is in the region (3) defined by the second switching line 42 and the third switching line 43, the mode is a switching mode for switching the turbocharger to be used.

  When the behavior state of the engine 10 is in the region (4) defined by the third switching line 43 and the fourth switching line 44, the mode is set to the twin turbo mode.

  When the behavior state of the engine 10 is in the region (5) defined by the fourth switching line 44 and the fifth switching line 45, the twin turbo mode and the waste gate open mode are set.

<Mode switching operation>
Here, the mode is a switching mode for switching the turbocharger from the primary turbocharger 4 to the primary turbocharger 4 and the secondary turbocharger 5 from the primary turbocharger 4 to the twin turbo mode. It is assumed that the mode can be switched in the order of twin turbo mode and waste gate open mode.

  By reading the detection signals from the engine speed sensor 31, the accelerator opening sensor 32, the gear position sensor 33 and the intake pressure sensor 34, the behavior state of the engine 10 is in the region (1) shown in FIG. When the ECU 30 determines that the gear position is the neutral position, the ECU 30 determines the rotational opening degree of the rotary body 26 of the rotary valve 15 to the first, second, and third gate chambers 21, as shown in FIG. A fully closed state in which the openings 22 and 23 are closed is assumed. Thereby, the mode is set to the turbo bypass mode and the exhaust throttle mode when cold.

  The ECU 30 determines that the behavior state of the engine 10 is in the region (2) shown in FIG. 4 by reading each detection signal from the engine speed sensor 31, the accelerator opening sensor 32, the gear position sensor 33, and the intake pressure sensor 34. In this case, as shown in FIG. 6, the ECU 30 rotates the rotary body 26 of the rotary valve 15 by a predetermined angle in the clockwise direction from the state of FIG. 5, thereby setting the rotational opening of the rotary body 26 to the first gate chamber. 21 is opened, and the openings of the second and third gate chambers 22 and 23 are closed. Thereby, the exhaust gas is supplied to the turbine 4B of the primary turbocharger 4 through the first gate chamber 21, the first port 16, and the first exhaust passage portion 11A, and the turbine 4B passes through the first exhaust passage portion 11A. Rotates by passing exhaust gas. As a result, the mode is a single turbo mode.

  The ECU 30 determines that the behavior state of the engine 10 is in the region (3) shown in FIG. 4 by reading each detection signal from the engine speed sensor 31, the accelerator opening sensor 32, the gear position sensor 33, and the intake pressure sensor 34. In this case, as shown in FIG. 7, the ECU 30 rotates the rotary body 26 of the rotary valve 15 from the state of FIG. 6 by a predetermined angle in the clockwise direction, thereby setting the rotational opening of the rotary body 26 to the first gate chamber. 21 and a part of the opening of the second gate chamber 22 are opened, and the remaining area of the opening of the second gate chamber 22 and the opening of the third gate chamber 23 are closed. Thereby, in addition to the supply of the exhaust gas to the turbine 4B of the primary turbocharger 4, an amount of exhaust gas corresponding to the opening area of the opening of the second gate chamber 22 is supplied to the turbine 5B of the secondary turbocharger 5 2 and the second exhaust passage portion 11B, the turbine 5B is also rotated by the exhaust gas passing through the second exhaust passage portion 11B. As a result, the mode is a switching mode in which the used turbocharger is switched from the primary turbocharger 4 to both the primary turbocharger 4 and the secondary turbocharger 5.

  The ECU 30 determines that the behavior state of the engine 10 is in the region (4) shown in FIG. 4 by reading each detection signal from the engine speed sensor 31, the accelerator opening sensor 32, the gear position sensor 33, and the intake pressure sensor 34. In this case, as shown in FIG. 8, the ECU 30 rotates the rotary body 26 of the rotary valve 15 by a predetermined angle in the clockwise direction from the state shown in FIG. The respective openings of the gate chambers 21 and 22 are opened, and the opening of the third gate chamber 23 is closed. Thereby, the exhaust gas is supplied to the turbine 4B of the primary turbocharger 4 through the first gate chamber 21, the first port 16, and the first exhaust passage portion 11A, and the turbine 4B passes through the first exhaust passage portion 11A. Rotates by passing exhaust gas. At the same time, the exhaust gas is supplied to the turbine 5B of the secondary turbocharger 5 through the second gate chamber 22, the second port 17, and the second exhaust passage portion 11B, and the turbine 5B is connected to the second exhaust passage portion 11B. It is rotated by the exhaust gas passing through. As a result, the mode is a twin turbo mode.

  The ECU 30 determines that the behavior state of the engine 10 is in the region (5) shown in FIG. 4 by reading each detection signal from the engine speed sensor 31, the accelerator opening sensor 32, the gear position sensor 33, and the intake pressure sensor 34. In this case, as shown in FIG. 9, the ECU 30 rotates the rotary body 26 of the rotary valve 15 by a predetermined angle in the clockwise direction from the state shown in FIG. The third gate chambers 21, 22, and 23 are fully opened or almost fully opened. Thereby, in addition to the supply of exhaust gas to the turbine 4B of the primary turbocharger 4 and the turbine 5B of the secondary turbocharger 5, exhaust gas is supplied to the catalyst through the third gate chamber 23, the waste gate port 18 and the communication passage 19. Supplied. As a result, the modes are a twin turbo mode and a waste gate open mode.

  In particular, in the single turbo mode and in the switching mode in which the used turbocharger is switched from the primary turbocharger 4 to both the primary turbocharger 4 and the secondary turbocharger 5, the intake air switching valve 6 is in the closed state, so that the intake air bypass The differential pressure in the upstream and downstream intake bypass passages 7 across the valve 8 becomes a predetermined pressure or more, and the intake bypass valve 8 is opened, and the intake air circulates between the second intake passage portion 3B and the intake bypass passage 7. . Thereby, the burn-in of the compressor 5A of the secondary turbocharger 5 is prevented.

  In the twin turbo mode, since the intake switching valve 6 is opened, the differential pressure in the upstream and downstream intake bypass passages 7 sandwiching the intake bypass valve 8 becomes equal to or lower than a predetermined value, and the intake bypass valve 8 is closed. . Therefore, the intake air is supplied to the intercooler 9 through the second intake passage portion 3B.

  As is apparent from the above description, according to the present embodiment, the rotary valve 15 is used as a flow control valve for the exhaust gas of the internal combustion engine 10 supplied to the turbine 4B of the primary turbocharger 4 and the turbine 5B of the secondary turbocharger 5. Thus, the flow rate control of the exhaust gas to the first and second ports 16 and 17 and the waste gate port 18 and the switching of the used turbocharger are performed according to the rotational opening of the rotary body 26 of the rotary valve 15. Therefore, the cost and space saving of the parallel sequential turbo system can be realized.

[Second Embodiment]
FIG. 10 is a plan view showing a configuration of a rotary valve applied to the sequential turbo system according to the second embodiment of the present invention.

  Referring to FIG. 10, the sequential turbo system according to the present embodiment is characterized in that the first, second and third gate chambers 21, 22 and 23 of the rotary valve 15 have a shape in which the cross-sectional area change is moderated. The other configuration is the same as that of the first embodiment.

  In the example shown in FIG. 10, each opening of the first, second and third gate chambers 23 is counterclockwise from the upper end of the left edge of the substantially sector-shaped main regions 51, 52 and 53 concentric with the shaft 25. It has a shape having projecting regions 54, 55, and 56 projecting in a bird's beak shape (bird cage shape) in the circumferential direction. The protruding region 55 of the opening of the second gate chamber 22 overlaps the upper end of the right edge of the opening of the first gate chamber 21, and the protruding region 56 of the opening of the third gate chamber 23. Is overlapped with the upper end of the right edge of the opening of the second gate chamber 22. The main regions 54 and 55 of the openings of the first and second gate chambers 21 and 22 are shaped so that the protrusions 55 and 56 of the openings of the second and third gate chambers 22 and 23 do not overlap. The change in the cross-sectional area of the first, second and third gate chambers 21, 22, and 23 may be moderate.

  In the present embodiment, when the rotational opening degree of the rotary body 26 of the rotary valve 15 is suddenly increased, the supercharging pressure is reduced. However, the shafts are provided in the openings of the first, second and third gate chambers 23. Main areas 51, 52, 53 concentric with 25 and projecting areas 54, 55, 56 projecting in a bird's beak shape counterclockwise from the upper end of the left edge of the main areas 51, 52, 53. Since the first, second, and third gate chambers 21, 22, and 23 of the rotary valve 15 are provided with a shape in which the cross-sectional area change is moderated, the first and second ports 16, 17 and When the exhaust gas flow rate control to the waste gate port 18 and the switching of the turbo used are performed, the rotational opening degree of the rotating body 26 can be gradually increased so that the run-up is performed. As a result, the run-up from the exhaust throttle mode to the single turbo mode, the run-up when the used turbo is switched, and the control of gas introduction to the waste gate port 18 become smooth.

[Third embodiment]
<Overall configuration>
FIG. 11 is a diagram showing a simplified configuration of a sequential turbo system according to the third embodiment of the present invention.

  Referring to FIG. 11, the sequential turbo system 1 according to the present embodiment is a series sequential turbo system, and includes the air cleaner 2, the intake passage 3, the intercooler 9, the engine 10, the exhaust passage 11, and the EGR passage 12. In addition to the EGR valve 13, the EGR cooler 14, and the rotary valve 15, a low-pressure stage turbocharger 60, a high-pressure stage turbocharger 61, a high-pressure stage compressor bypass passage 62, and a high-pressure stage compressor bypass valve 63 are provided. In this system 1, the low-pressure stage turbocharger 60 and the high-pressure stage turbocharger 61 are arranged in series.

  The intake passage 3 is connected to the engine 10 via the intercooler 9 without branching in the middle as in the first embodiment. In the intake passage 3, a compressor 60A of the low-pressure stage turbocharger 60 and a compressor 60B of the high-pressure stage turbocharger 61 are arranged in this order from the upstream side to the downstream side with respect to the intake passage.

  Further, a high-pressure compressor bypass passage 62 is provided in the intake passage 3. One end of the high-pressure stage compressor bypass passage 62 is connected to the intake passage 3 between the compressor 60 A of the low-pressure stage turbocharger 60 and the compressor 60 B of the high-pressure stage turbocharger 61, and the other end of the high-pressure stage turbocharger 61. It is connected to the intake passage 3 between the compressor 60B and the intercooler 9.

  A high pressure compressor bypass valve 63 is connected in the high pressure compressor bypass passage 62. The opening and closing of the high-pressure compressor bypass valve 63 is controlled by a control signal supplied from the ECU 30 shown in FIG.

  An EGR passage 12 is connected in the exhaust passage 11. The EGR passage 12 has one end connected to the exhaust passage 11 and the other end connected to the intake passage 3.

  Similarly to the first embodiment, the exhaust passage 11 is branched into two systems of a first exhaust passage portion 11A and a second exhaust passage portion 11B in the middle. A turbine 61A of a high-pressure stage turbocharger 61 is disposed in the first exhaust passage portion 11A, while a turbine 60A of a low-pressure stage turbocharger 60 is disposed in the second exhaust passage portion 11B.

  The turbine 61A of the high-pressure stage turbocharger 61 is rotated by the exhaust gas passing through the first exhaust passage portion 11A, while the turbine 60B of the low-pressure stage turbocharger 60 is exhausted gas passing through the second exhaust passage portion 11B. Is rotated by. Such rotational torques of the turbines 60B and 61A are transmitted to the compressor 60A in the low-pressure stage turbocharger 60 and the compressor 60B in the high-pressure stage turbocharger 61 so as to be supercharged.

  A rotary valve 15 is provided at a branch portion where the exhaust passage 11 branches into the first exhaust passage portion 11A and the second exhaust passage portion 11B. The rotary valve 15 functions as a flow control valve for the exhaust gas of the engine 10 supplied to the turbine 61B of the high-pressure stage turbocharger 61 and the turbine 60B of the low-pressure stage turbocharger 60. The rotary body shown in FIG. 26 through the first port 16 connected to the turbine 61B of the high-pressure turbocharger 61 via the first exhaust passage portion 11A and the second exhaust passage portion 11B. The flow rate control of the exhaust gas to the second port 17 connected to the turbine 60B of the low-pressure stage turbocharger 60 and the waste gate port 18 connected to the catalyst via the communication path 19 and switching of the used turbocharger are performed.

<Rotary valve>
FIG. 12 is a plan view showing the configuration of the rotary valve.

  Referring to FIG. 12, the rotary valve 15 includes a first gate chamber 21 spaced from the second gate chamber 22 and a third gate chamber 23 adjacent to the second gate chamber 22. Has been placed. The opening forming regions of the first, second and third gate chambers 21, 22 and 23 are set in a range of 180 degrees or more around the axis 25. Correspondingly, the rotating body 26 includes a plate-like member having a cover surface of 180 degrees or more so that the openings of the first, second, and third gate chambers 21, 22, and 23 can be fully closed and fully opened. Has been. Other configurations are the same as those of the rotary valve shown in the second embodiment. That is, each opening of the first, second and third gate chambers 21, 22, 23 of the rotary valve 15 is provided with main regions 51, 52, 53 and projecting regions 54, 55, 56. It has a shape with a gradual change in cross-sectional area.

<Electrical configuration>
FIG. 13 is a diagram showing an electrical configuration of the sequential turbo system.

  Similar to the first embodiment, the sequential turbo system 1 includes an ECU 30 that includes a CPU, a ROM, a RAM, a backup RAM, and the like. The ECU 30 is supplied with detection signals from an engine speed sensor 31, an accelerator opening sensor 32, a gear position sensor 33, and an intake pressure sensor 34. Based on these detection signals, the ECU 30 The drive of the valve 15 and the high pressure compressor bypass valve 63 is controlled.

  In particular, the ECU 30 controls the actuator 72 driven by the VSV 71 to open and close the high-pressure compressor bypass valve 63.

<Map>
FIG. 14 is a diagram showing the configuration of the mode switching map of the sequential turbo system. This map is stored in the ROM in the ECU 30.

  Referring to FIG. 14, when the behavior state of engine 10 is in a region (11) defined by first switching line 81, the mode is a cold turbo bypass mode and an exhaust throttle mode.

  When the behavior state of the engine 10 is in the region (12) defined by the first switching line 81 and the second switching line 82, the mode is set to the high-pressure stage turbo mode.

  When the behavior state of the engine 10 is in the region (13) defined by the second switching line 82 and the third switching line 83, the mode is a switching mode for switching the turbocharger to be used.

  When the behavior state of the engine 10 is in the region (14) defined by the third switching line 83 and the fourth switching line 84, the mode is set to the low pressure turbo mode.

  When the behavior state of the engine 10 is in the region (15) defined by the fourth switching line 84 and the fifth switching line 85, the low-pressure stage turbo mode and the waste gate open mode are set.

<Mode switching operation>
Here, the mode is a cold turbo bypass mode and an exhaust throttle mode → high pressure stage turbo mode → switching mode in which the turbocharger to be used is switched from the high pressure stage turbocharger 61 to the low pressure stage turbocharger 60 → low pressure stage turbo mode → low pressure The description will be made assuming that the switching can be performed in the order of the stage turbo mode and the wastegate open mode.

  By reading the detection signals from the engine speed sensor 31, the accelerator opening sensor 32, the gear position sensor 33, and the intake pressure sensor 34, the behavior state of the engine 10 is in the region (1) shown in FIG. When the ECU 30 determines that the gear position is the neutral position, the ECU 30 determines the rotational opening degree of the rotary body 26 of the rotary valve 15 as shown in FIG. A fully closed state in which the openings 22 and 23 are closed is assumed. Thereby, the mode is set to the turbo bypass mode and the exhaust throttle mode when cold.

  The ECU 30 determines that the behavior state of the engine 10 is in the region (12) shown in FIG. 14 by reading detection signals from the engine speed sensor 31, the accelerator opening sensor 32, the gear position sensor 33, and the intake pressure sensor 34. When this is done, the ECU 30 rotates the rotary body 26 of the rotary valve 15 by a predetermined angle in the clockwise direction from the state shown in FIG. 15, thereby changing the rotational opening of the rotary body 26 to the first gate chamber. 21 is opened, and the openings of the second and third gate chambers 22 and 23 are closed. Thereby, the exhaust gas is supplied to the turbine 61A of the high-pressure stage turbocharger 61 through the first gate chamber 21, the first port 16, and the first exhaust passage portion 11A, and the turbine 61A is supplied to the first exhaust passage portion 11A. It is rotated by the exhaust gas passing through. As a result, the mode is a low-pressure turbo mode.

  The ECU 30 determines that the behavior state of the engine 10 is in the region (13) shown in FIG. 14 by reading the detection signals from the engine speed sensor 31, the accelerator opening sensor 32, the gear position sensor 33, and the intake pressure sensor 34. When this is done, the ECU 30 rotates the rotary body 26 of the rotary valve 15 by a predetermined angle in the clockwise direction from the state shown in FIG. 16, thereby changing the rotational opening of the rotary body 26 to the first gate chamber. 21 and a part of the opening of the second gate chamber 22 are opened, and the remaining area of the opening of the second gate chamber 22 and the opening of the third gate chamber 23 are closed. Thereby, in addition to the supply of the exhaust gas to the turbine 61A of the high-pressure stage turbocharger 61, an amount of exhaust gas corresponding to the opening area of the opening of the second gate chamber 22 is supplied to the turbine 60B of the low-pressure stage turbocharger 60. Supplyed through the second port 17 and the second exhaust passage portion 11B, the turbine 60B is also rotated by the exhaust gas passing through the second exhaust passage portion 11B. At this time, the high pressure compressor bypass valve 63 in the high pressure compressor bypass passage 62 is opened by the ECU 30. As a result, the mode is a switching mode in which the used turbocharger is switched from the high-pressure stage turbocharger 61 to the low-pressure stage turbocharger 60.

  The ECU 30 determines that the behavior state of the engine 10 is in the region (14) shown in FIG. 14 by reading detection signals from the engine speed sensor 31, the accelerator opening sensor 32, the gear position sensor 33, and the intake pressure sensor 34. In this case, as shown in FIG. 18, the ECU 30 rotates the rotary body 26 of the rotary valve 15 by a predetermined angle in the clockwise direction from the state shown in FIG. 17, thereby setting the rotational opening of the rotary body 26 to the first and third. The respective openings of the gate chambers 21 and 23 are closed and the opening of the second gate chamber 22 is opened. Thereby, the exhaust gas is supplied to the turbine 60B of the low-pressure stage turbocharger 60 through the second gate chamber 22, the second port 17, and the second exhaust passage portion 11B, and the turbine 60B is supplied to the second exhaust passage portion 11B. It is rotated by the exhaust gas passing through. As a result, the mode is a low-pressure turbo mode.

  The ECU 30 determines that the behavior state of the engine 10 is in the region (15) shown in FIG. 14 by reading each detection signal from the engine speed sensor 31, the accelerator opening sensor 32, the gear position sensor 33, and the intake pressure sensor 34. When this is done, the ECU 30 rotates the rotary body 26 of the rotary valve 15 by a predetermined angle in the clockwise direction from the state shown in FIG. 18, thereby changing the rotational opening of the rotary body 26 to the first gate chamber. 21 is closed and each opening of the second and third gate chambers 22 and 23 is opened. Thereby, in addition to the supply of the exhaust gas to the turbine 60B of the low-pressure stage turbocharger 60, the exhaust gas is supplied to the catalyst through the third gate chamber 23, the waste gate port 18 and the communication passage 19. As a result, the modes are the low-pressure stage turbo mode and the wastegate open mode.

  As is apparent from the above description, according to the present embodiment, the rotary valve 15 is used as a flow control valve for the exhaust gas of the internal combustion engine 10 supplied to the turbine 4B of the primary turbocharger 4 and the turbine 5B of the secondary turbocharger 5. Thus, the flow rate control of the exhaust gas to the first and second ports 16 and 17 and the waste gate port 18 and the switching of the used turbocharger are performed according to the rotational opening of the rotary body 26 of the rotary valve 15. Therefore, it is possible to reduce the cost and space of the series sequential turbo system.

  Further, when the rotational opening degree of the rotary body 26 of the rotary valve 15 is suddenly increased, the supercharging pressure is reduced. However, the main regions 51, 52, 53 and the projecting regions 54, 55, 56 are provided so that the first, second, and third gate chambers 21, 22, 23 of the rotary valve 15 have a shape in which the cross-sectional area change is moderated. When the exhaust gas flow rate control to the first and second ports 16 and 17 and the waste gate port 18 and the switching of the turbo used are performed, the rotational opening of the rotating body 26 is gradually increased so that the running is performed. Can continue. As a result, the run-up from the exhaust throttle mode to the high-pressure turbo mode, the run-up at the time of switching to the used turbo, and the control of gas introduction to the waste gate port 18 become smooth.

  The present invention is not limited to the above embodiment.

  For example, in the first embodiment, the opening formation regions of the first, second, and third gate chambers 21, 22, and 23 of the rotary valve 15 are set to a range of 180 degrees around the axis 25, An example has been described in which the rotating body 26 is a semicircular plate-like member so that the openings of the first, second, and third gate chambers 21, 22, and 23 can be fully closed and fully opened. However, the present invention is not limited to such a configuration. As shown in FIG. 20, the range of 180 degrees or less is set around the shaft 25, and the opening of the first, second and third gate chambers 21, 22, and 23 can be fully closed and fully opened. Thus, even if it is a plate-shaped member having a cover surface of 180 degrees or more, the object of the present invention can be sufficiently achieved.

  In the third embodiment, the main regions 51, 52, 53 and the projecting regions 54, 55, and the opening regions of the first, second, and third gate chambers 21, 22, 23 of the rotary valve 15 are provided. The example in which the first, second, and third gate chambers 21, 22, and 23 have a shape in which the cross-sectional area change is moderated by providing 56 is described. However, the present invention is not limited to such a configuration. Without providing the projecting regions 54, 55, 56 at the openings of the first, second, and third gate chambers 21, 22, 23 of the rotary valve 15, the first, second, and third gate chambers 21, The configuration may be such that the shapes 22 and 23 do not gently change the cross-sectional area.

  It goes without saying that various design changes and modifications can be made within the scope of the claims attached to this specification.

It is a figure which simplifies and shows the structure of the sequential turbo system concerning the 1st Embodiment of this invention. It is a top view which shows the structure of a rotary valve. It is a figure which shows the electric constitution of the sequential turbo system. It is a figure which shows the structure of the mode switching map of the sequential turbo system. It is a figure which shows the state of the rotary valve at the time of turbo bypass mode and exhaust throttling mode. It is a figure which shows the state of the rotary valve at the time of single turbo mode. It is a figure which shows the state of the rotary valve at the time of use turbocharger switching. It is a figure which shows the state of the rotary valve at the time of twin turbo mode. It is a figure which shows the state of the rotary valve at the time of a twin turbo mode and a waste gate open mode. It is a top view which shows the structure of the rotary valve applied to the sequential turbo system concerning the 2nd Embodiment of this invention. It is a figure which simplifies and shows the structure of the sequential turbo system concerning the 3rd Embodiment of this invention. It is a top view which shows the structure of a rotary valve. It is a figure which shows the electric constitution of the sequential turbo system. It is a figure which shows the structure of the mode switching map of the sequential turbo system. It is a figure which shows the state of the rotary valve at the time of turbo bypass mode and exhaust throttling mode. It is a figure which shows the state of the rotary valve at the time of a high pressure stage turbo mode. It is a figure which shows the state of the rotary valve at the time of use turbo switching. It is a figure which shows the state of the rotary valve at the time of low pressure stage turbo mode. It is a figure which shows the state of the rotary valve at the time of low pressure turbo mode and wastegate open mode. It is a top view which shows the structure of the modification of the rotary valve applied to the sequential turbo system concerning the 1st Embodiment of this invention.

Explanation of symbols

1 Sequential Turbo System 4 Primary Turbocharger 5 Secondary Turbocharger 10 Internal Combustion Engine (Engine)
15 Rotary valve 16 1st port 17 2nd port 18 Waste gate port 21 1st gate chamber 22 2nd gate chamber 23 3rd gate chamber 60 Low pressure stage turbocharger 61 High pressure stage turbocharger

Claims (3)

A sequential turbo system in which a rotary valve is used as a flow control valve for exhaust gas of an internal combustion engine supplied to the first and second turbochargers,
The rotary valve is
A cylindrical body,
First, second and third gate chambers formed to penetrate the body in the axial direction;
A rotating body that is rotatably supported around an axis on a control surface that is an end surface of the body and on which the first, second, and third gate chambers are open,
The first gate chamber is connected to a first port connected to the first turbocharger;
The second gate chamber is connected to a second port connected to the second turbocharger;
The third gate chamber is connected to a waste gate port leading to the catalyst;
The first, second and third gate chambers are arranged in this order along the rotation direction in which the rotating body opens each opening of the first, second and third gate chambers,
A sequential turbo system characterized in that the flow rate control of the exhaust gas to the first and second ports and the waste gate port and the switching of the used turbocharger are performed in accordance with the rotational opening of the rotating body. The sequential turbo system according to claim 1,
The sequential turbo system according to claim 1, wherein the first, second and third gate chambers have a shape in which a change in cross-sectional area is moderated. In the sequential turbo system according to claim 1 or 2,
The sequential turbo system characterized in that a driving source of the rotating body is a motor.

Images