JP2009144665A - Turbo supercharger and supercharging engine system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress decrease of a supercharging pressure and to suppress increase of a pressure at a turbine inlet. <P>SOLUTION: A communication control valve 28 is capable of selectively switching between a communication state for communicating a plurality of scroll passages 21-23 at an upstream side from a nozzle 26 and a shutting state for shutting communication of the plurality of scroll passages 21-23 at the upstream side from the nozzle 26. When an internal combustion engine is operated at a low speed, exhaust gases respectively flowed from respective cylinders to the respective scroll flow passages 21-23 are supplied to the nozzle 26 without mutual interference by controlling the communication control valve 28 to be in the shutting state. When the internal combustion engine is operated at a high speed, the exhaust gases respectively flowed from respective cylinders to the respective scroll flow passages 21-23 are supplied to the nozzle 26 while mutually interfering by controlling the communication control valve 28 to be in a communicating state. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a turbocharger that pressurizes intake air into an engine by using exhaust energy of an engine having a plurality of cylinders, and a supercharged engine system.

  A turbocharger (turbocharger) is used as a supercharging device that pressurizes intake air into the engine. The turbocharger uses the exhaust energy of the engine to generate rotational power in the turbine wheel, and rotates the compressor wheel using the rotational power of the turbine wheel to pressurize the intake air to the engine.

  In the turbocharger, when the engine speed is low, the flow rate of exhaust gas supplied to the turbine decreases, so that the supercharging pressure does not easily increase. Therefore, in order to quickly increase the supercharging pressure when the engine speed is low, a variable nozzle turbocharger in which a movable vane is provided in the nozzle between the scroll path of the turbine and the turbine wheel has been proposed ( For example, Non-Patent Document 1). In this variable nozzle turbocharger, when the engine speed is low and the flow rate of exhaust gas supplied to the turbine is small, the flow area between the movable vanes is reduced to flow into the flow path between the blades of the turbine wheel. Increase the supercharging pressure by increasing the flow rate of exhaust gas. On the other hand, when the engine speed is high and the flow rate of exhaust gas supplied to the turbine is large, the flow area between the movable vanes is increased so that a large flow rate of exhaust gas flows from the nozzle to the flow path between the blades of the turbine wheel. So that it is controlled.

  Further, since the exhaust gas after combustion is exhausted from the engine cylinder to the exhaust passage when the exhaust valve is open, the exhaust gas exhausted to the exhaust passage is pulsated (pulsed) as the exhaust valve opens and closes. Flow). When the engine is a multi-cylinder engine having a plurality of cylinders, the cycle of the intake stroke-compression stroke-expansion stroke-exhaust stroke is shifted for each cylinder. The phases are different from each other. For this reason, when exhaust gases from the cylinders are combined in a common exhaust passage and then supplied to the turbine, the exhaust gases supplied from the cylinders interfere with each other and the pulsation attenuates, whereby the exhaust gas supplied to the turbine. Energy is reduced. As a result, particularly when the engine speed is low (the exhaust gas flow rate supplied to the turbine is small), the supercharging pressure is unlikely to increase. Therefore, in order to suppress a decrease in exhaust energy due to exhaust interference between the cylinders, a twin scroll turbocharger in which the scroll flow path of the turbine is divided into two has been proposed (for example, Patent Document 1 and Non-Patent Document 1). In this twin scroll turbocharger, exhaust gas from some cylinders is supplied to one of the two divided scroll flow paths, and exhaust gas from the remaining cylinders is supplied to the other of the two divided scroll flow paths. By doing so, the influence of the exhaust interference between the cylinders is reduced.

JP 63-117124 A "Journal of the Gas Turbine Society of Japan", The Gas Turbine Society of Japan, May 2000, Vol.28, No.3, p.27,74

  In the variable nozzle type turbocharger, exhaust gases from the cylinders are combined in a common exhaust passage and then supplied to the turbine. Therefore, the exhaust gases from the cylinders interfere with each other and the pulsation is attenuated. Exhaust energy supplied to is reduced. For this reason, the boost pressure is reduced by the amount of pulsation of exhaust gas from each cylinder being attenuated.

  In a twin scroll turbocharger, reducing the influence of exhaust interference between cylinders is effective in increasing the supercharging pressure when the engine speed is low, but the engine speed is high and When the exhaust gas flow rate to be supplied is large, the engine back pressure (turbine inlet pressure) tends to increase. When the turbine inlet pressure becomes high, the exhaust gas after combustion becomes difficult to be discharged from the cylinder of the engine, and the pumping loss of the engine increases.

  An object of the present invention is to provide a turbocharger and a supercharged engine system capable of suppressing a decrease in supercharging pressure and suppressing an increase in turbine inlet pressure.

  The turbocharger and the supercharged engine system according to the present invention employ the following means in order to achieve the above-described object.

  A turbocharger according to the present invention is a turbocharger that pressurizes intake air into an engine by using exhaust energy of engines having pulsation phases different from each other in exhaust gases from a plurality of cylinders. A plurality of scroll channels provided for each cylinder, each of which has a plurality of scroll channels into which exhaust gas from each cylinder flows, and a nozzle into which exhaust gas from the plurality of scroll channels flows. A turbine wheel that rotates using the energy of exhaust gas supplied through the nozzle, a compressor that pressurizes intake air to the engine using the rotational power of the turbine wheel, and a plurality of scrolls upstream of the nozzle Select between a communication state in which the flow paths communicate with each other and a blocking state in which communication between the plurality of scroll flow paths on the upstream side of the nozzle is blocked When the communication control valve is in a communication state, the exhaust gas flowing into each scroll flow path from each cylinder interferes with each other and is supplied to the nozzle. When the communication control valve is in the shut-off state, the gist is that the exhaust gas flowing into each scroll flow path from each cylinder is supplied to the nozzle without interfering with each other.

  In one aspect of the present invention, the apparatus further includes a communication chamber for communicating the plurality of scroll flow paths with each other upstream from the nozzle, and the communication control valve includes a plurality of scroll flow paths and communication chambers upstream from the nozzle. It is preferable that it is possible to selectively switch between a communication state in which communication is established and a blocking state in which communication between the plurality of scroll flow paths and the communication chamber on the upstream side of the nozzle is blocked.

  In one aspect of the present invention, the communication control valve is selectively switched between a communication state and a shut-off state according to the engine speed, and the engine speed when the communication control valve is in the communication state is It is preferable that the engine speed be higher than that when the communication control valve is in the shut-off state.

  A supercharged engine system according to the present invention includes an engine having different pulsation phases generated in exhaust gases from a plurality of cylinders, and a turbocharger that pressurizes intake air into the engine using engine exhaust energy. The turbocharger is a turbocharger according to the present invention.

  In the present invention, when the communication control valve is in the shut-off state, the exhaust gas flowing into each scroll flow path from each cylinder is supplied to the nozzle without interfering with each other and with almost no attenuation of the pulsation. Since a decrease in exhaust energy due to exhaust interference between the cylinders can be suppressed, a decrease in supercharging pressure can be suppressed. In addition, when the communication control valve is in a communication state, exhaust gas that has flowed into each scroll channel from each cylinder interferes with each other and is supplied to the nozzle, whereby the pulsation of the exhaust gas is attenuated, Since the flow passage area of the exhaust gas flowing through the scroll flow passage is multiplied by the number of cylinders and the flow passage resistance is reduced, an increase in turbine inlet pressure can be suppressed. Therefore, according to the present invention, a decrease in supercharging pressure can be suppressed, and an increase in turbine inlet pressure can be suppressed.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

  1-3 is a figure which shows schematic structure of a supercharged engine system provided with the turbocharger 12 which concerns on embodiment of this invention, FIG. 1 shows the outline of the whole structure of a supercharged engine system, FIG. FIG. 3 shows the internal configuration of the turbine 20 of the turbocharger 12 as viewed from the direction perpendicular to the axial direction of the turbine wheel 24, and FIG. 3 shows the turbine 20 of the turbocharger 12 as viewed from the direction parallel to the axial direction of the turbine wheel 24. The internal structure of is shown. A turbocharger (turbocharger) 12 according to the present embodiment pressurizes intake air to the internal combustion engine 10 using exhaust energy of the internal combustion engine 10, and a turbine using exhaust energy of the internal combustion engine 10. A turbine 20 that generates rotational power in the wheel 24 and a compressor 18 that pressurizes intake air to the internal combustion engine 10 using the rotational power of the turbine wheel 24 are provided.

  The internal combustion engine 10 is a multi-cylinder engine having a plurality of cylinders. FIG. 1 shows an example in which the internal combustion engine 10 is an in-line three-cylinder engine having three cylinders 1 to 3. In each of the cylinders 1 to 3, when the exhaust valve is open, the exhaust gas after combustion is discharged into the exhaust passages 31 to 33 provided corresponding to the cylinders 1 to 3, respectively. In the exhaust gas discharged into the exhaust passages 31 to 33, pulsation (pulse flow) is generated as the exhaust valve is opened and closed. In the internal combustion engine 10, the cycle of the intake stroke-compression stroke-expansion stroke-exhaust stroke is shifted for each cylinder. Therefore, the phases of pulsations generated in the exhaust gas from each cylinder of the internal combustion engine 10 are different from each other. For example, in the case of an in-line three-cylinder four-stroke cycle engine, in each of the cylinders 1 to 3, the cycle of the intake stroke, the compression stroke, the expansion stroke, and the exhaust stroke is shifted by 240 degrees in terms of crank angle, as shown in FIG. The phase of the pulsation (pulse flow) generated in the pressure wave of the exhaust gas discharged from the cylinders 1 to 3 to the exhaust passages 31 to 33 is shifted by approximately 240 ° in terms of the crank angle.

  A turbine 20 of the turbocharger 12 includes spiral scroll channels 21 to 23 into which exhaust gas from each cylinder of the internal combustion engine 10 flows, and nozzles 26 into which exhaust gas from the scroll channels 21 to 23 flows. , And a turbine wheel 24 that generates rotational power by being rotationally driven using the energy of the exhaust gas supplied through the nozzle 26. The nozzle 26 is located on the radially outer side of the turbine wheel 24, and the scroll channels 21 to 23 are located on the radially outer side of the turbine wheel than the nozzle 26. A compressor wheel 19 of the compressor 18 is connected to a turbine wheel 24 via a shaft (rotating shaft) 17, and the compressor wheel 19 is driven to rotate together with the turbine wheel 24, whereby the intake air to the internal combustion engine 10 is compressed. . The intake air pressurized by the compressor 18 is cooled by the intercooler 13 and then supplied into the cylinders 1 to 3 when the intake valve is open.

  In the present embodiment, the scroll flow path of the turbine 20 is provided in the same number as the number of cylinders corresponding to each cylinder of the internal combustion engine 10, and the exhaust gas from each cylinder flows into each scroll flow path. In an example in which the internal combustion engine 10 is a three-cylinder engine, three scroll flow paths 21 to 23 that are divided from each other are provided for each of the cylinders 1 to 3. The scroll passage 21 communicates with the exhaust passage 31 so that the exhaust gas from the cylinder 1 flows into the scroll passage 21. The scroll passage 22 communicates with the exhaust passage 32, so that exhaust gas from the cylinder 2 flows into the scroll passage 22, and the scroll passage 23 communicates with the exhaust passage 33, so that the cylinder The exhaust gas from 3 flows into the scroll channel 23. As described above, the phases of pulsation (pulse flow) generated in the exhaust gas from each of the cylinders 1 to 3 are different from each other. In the example shown in FIGS. 2 and 3, the scroll flow path of the turbine 20 is divided into three scroll flow paths 21 to 23 in the radial direction of the turbine wheel 24. Exhaust gas in each of the scroll channels 21 to 23 is supplied to the inter-blade channel of the turbine wheel 24 through the nozzle 26. In that case, the flow rate of the exhaust gas supplied to the flow path between the blades of the turbine wheel 24 is increased by converting the pressure of the exhaust gas into the speed by the nozzle 26. In the nozzle 26, a flow path 26-1 into which exhaust gas mainly from the scroll flow path 21 flows, a flow path 26-2 into which exhaust gas mainly flows from the scroll flow path 22, and a scroll flow path mainly. A flow path 26-3 into which exhaust gas from 23 flows is formed side by side along the circumferential direction of the turbine wheel 24.

  Furthermore, in the present embodiment, the turbine 20 is provided with a communication chamber 25 for allowing the plurality of scroll flow paths 21 to 23 to communicate with each other upstream of the nozzle 26. Here, “upstream side” represents the upstream side in the exhaust gas flow direction. In the example shown in FIGS. 2 and 3, the communication chamber 25 is formed so as to protrude from the scroll flow paths 21 to 23 in the axial direction of the shaft 17, and is open to the scroll flow paths 21 to 23. In the communication chamber 25, a communication control valve 28 for controlling the communication state between the plurality of scroll channels 21 to 23 on the upstream side of the nozzle 26 is provided. In the example shown in FIG. 3, the communication chamber 25 and the communication control valve 28 are disposed near the inlets of the scroll channels 21 to 23. The communication control valve 28 includes a communication state (open state shown in FIG. 2) in which the plurality of scroll channels 21 to 23 communicate with the communication chamber 25 on the upstream side of the nozzle 26, and a plurality of scrolls on the upstream side of the nozzle 26. It is possible to selectively switch to a blocked state (closed state shown in FIG. 4) in which the communication between the flow paths 21 to 23 and the communication chamber 25 is blocked. In the example shown in FIGS. 2 and 3, the communication control valve 28 can be driven along the axial direction of the shaft 17, and by driving the communication control valve 28 toward the scroll flow paths 21 to 23, The opening part to each scroll flow path 21-23 is closed, and it switches to the interruption | blocking state. On the other hand, by driving the communication control valve 28 to the side opposite to the scroll flow paths 21 to 23, the openings to the respective scroll flow paths 21 to 23 of the communication chamber 25 are opened and switched to the communication state. When the communication control valve 28 is in a communication state, the plurality of scroll channels 21 to 23 communicate with each other via the communication chamber 25 on the upstream side of the nozzle 26 as shown in FIG. On the other hand, when the communication control valve 28 is in the shut-off state, as shown in FIG. 4, the communication between the plurality of scroll channels 21 to 23 on the upstream side of the nozzle 26 is blocked. The communication control valve 28 here can be driven by an actuator (not shown), for example. The drive control of the communication control valve 28 can be performed by, for example, a control command output from the electronic control unit.

  Next, the operation of the turbocharger 12 according to this embodiment will be described.

  When the internal combustion engine 10 is operated at a low speed, the electronic control unit controls the communication control valve 28 to be shut off by closing the communication control valve 28. That is, as shown in FIG. 4, the plurality of scroll channels 21 on the upstream side of the nozzle 26 are blocked by disconnecting the plurality of scroll channels 21 to 23 and the communication chamber 25 on the upstream side of the nozzle 26. Block communication between ~ 23. As a result, the exhaust gas flowing into the scroll channels 21 to 23 from the cylinders 1 to 3 is supplied to the nozzle 26 without the pressure waves interfering with each other. Therefore, the exhaust gas from the cylinders 1 to 3 flowing into the scroll flow paths 21 to 23 is supplied to the inter-blade flow path of the turbine wheel 24 with almost no attenuation of the level of pulsation (pulse flow). As a result, exhaust energy loss caused by attenuation of pressure wave pulsation of exhaust gas due to exhaust interference between the cylinders 1 to 3 can be reduced, and exhaust energy supplied to the inter-blade flow path of the turbine wheel 24 can be reduced. Can be reduced. Therefore, even if the flow rate of exhaust gas supplied to the turbine 20 is low when the internal combustion engine 10 is operated at low speed, the turbine wheel 24 can be efficiently rotated with high exhaust energy. As a result, when the internal combustion engine 10 is operated at a low speed, the supercharging pressure can be increased, and the torque of the internal combustion engine 10 can be increased.

  Further, since exhaust gases from the cylinders 1 to 3 do not interfere with each other and their pulsation hardly attenuates, as shown in FIG. 5, immediately after the exhaust valve is opened, the engine back pressure (exhaust pressure, turbine inlet) In the valve overlap period in which both the exhaust valve and the intake valve are open, the engine back pressure decreases and the intake pressure becomes higher than the engine back pressure. Therefore, the scavenging action can be strengthened and the intake flow rate can be increased. Also by this, the torque of the internal combustion engine 10 can be increased. Further, in the latter half of the exhaust stroke, the engine back pressure is reduced to be close to atmospheric pressure, so that the pumping loss of the internal combustion engine 10 is reduced.

  However, if the exhaust gases from the cylinders 1 to 3 do not interfere with each other, the exhaust gas pulsation period becomes shorter as the rotational speed of the internal combustion engine 10 becomes higher, so that the engine back pressure is reduced during the valve overlap period. It becomes difficult to decrease, and the scavenging action is weakened. Therefore, when the internal combustion engine 10 is operated at high speed, the electronic control unit controls the communication state by opening the communication control valve 28. That is, as shown in FIG. 2, by connecting the plurality of scroll channels 21 to 23 and the communication chamber 25 on the upstream side of the nozzle 26, the plurality of scroll channels 21 to 23 are connected to the upstream side of the nozzle 26. Communicate with each other. As a result, the exhaust gas flowing into the scroll flow paths 21 to 23 from the cylinders 1 to 3 is supplied to the nozzle 26 after the pressure waves interfere with each other. Therefore, as shown in FIG. 5, the exhaust gas flowing from the cylinders 1 to 3 flowing into the scroll channels 21 to 23 is attenuated in the level of pulsation (pulse flow) and the pressure is averaged. It is supplied to the inter-blade flow path of the turbine wheel 24. Furthermore, since the scroll flow paths 21 to 23 communicate with each other, the flow area of the exhaust gas flowing through the scroll flow path becomes several times the number of cylinders (three times in the examples shown in FIGS. 2 and 3). The channel resistance is reduced. Therefore, even if the flow rate of exhaust gas supplied to the turbine 20 during high-speed operation of the internal combustion engine 10 increases, the engine back pressure (turbine inlet pressure) can be reduced, so that the pumping loss of the internal combustion engine 10 can be reduced. Can do. Moreover, even if the flow rate of exhaust gas supplied to the turbine 20 is increased by controlling the communication control valve 28 to be in a communication state to attenuate the pulsation of the exhaust gas, the exhaust gas is bypassed to the turbine outlet side by the waste gate valve. Without making it happen, the supercharging pressure can be prevented from becoming excessive.

  In the above description of the operation, the electronic control unit determines that the internal combustion engine 10 is operating at a low speed when the rotational speed of the internal combustion engine 10 is less than or equal to the threshold value, and It can be determined that the engine 10 is operating at high speed. In this way, the communication control valve 28 can be selectively switched between the communication state and the shut-off state according to the rotational speed of the internal combustion engine 10, and the internal combustion engine 10 when the communication control valve 28 is in the communication state can be selected. The drive control of the communication control valve 28 can be performed so that the rotation speed is higher than the rotation speed of the internal combustion engine 10 when the communication control valve 28 is in the shut-off state.

  The electronic control unit can also continuously control the opening degree of the communication control valve 28. By controlling the opening degree of the communication control valve 28, it is possible to control the attenuation level of the pulsation of the exhaust gas flowing into each of the scroll flow paths 21 to 23 and to control the supercharging pressure. For example, the opening degree of the communication control valve 28 can be controlled to gradually increase with an increase in the rotational speed of the internal combustion engine 10. Further, the supercharging pressure (pressure in the intake passage) is detected by a pressure sensor (not shown), and the opening degree of the communication control valve 28 is controlled so that the detected supercharging pressure (pressure in the intake passage) matches the target value. You can also. Further, the intake flow rate can be detected by a flow sensor (not shown), and the opening degree of the communication control valve 28 can be controlled so that the detected intake flow rate matches the target value.

  As described above, in the present embodiment, by controlling the communication control valve 28 to be in a shut-off state when the internal combustion engine 10 is operated at a low speed, the exhaust gas flowing from the cylinders 1 to 3 into the scroll channels 21 to 23, respectively. The gases are supplied to the nozzle 26 without interfering with each other and with almost no attenuation of the pulsation. As a result, a reduction in exhaust energy due to exhaust interference between the cylinders 1 to 3 can be suppressed, so that the boost pressure can be increased. Further, by controlling the communication control valve 28 to be in a communication state during high-speed operation of the internal combustion engine 10, exhaust gases that have flowed into the scroll flow paths 21 to 23 from the cylinders 1 to 3 interfere with each other and enter the nozzle 26. Supplied. As a result, the pulsation of the exhaust gas is attenuated, and the flow area of the exhaust gas flowing through the scroll flow path is multiplied by the number of cylinders to reduce the flow resistance, thereby reducing the engine back pressure (turbine inlet pressure). Can do. Therefore, according to the present embodiment, a high supercharging pressure and a low engine back pressure (turbine inlet pressure) can be realized over a wide operating range of the internal combustion engine 10 from low speed operation to high speed operation.

  In the above embodiment, the case where the internal combustion engine 10 is a three-cylinder engine and the scroll flow path of the turbine 20 is divided into the three scroll flow paths 21 to 23 has been described. However, in the present embodiment, the number of cylinders of the internal combustion engine 10 can be arbitrarily set within a range of 2 or more. For example, FIGS. 6 and 7 show configuration examples of the turbine 20 when the internal combustion engine 10 is an in-line two-cylinder engine having two cylinders, a first cylinder and a second cylinder. 6 shows the internal configuration of the turbine 20 viewed from the direction perpendicular to the axial direction of the turbine wheel 24, and FIG. 7 shows the internal configuration of the turbine 20 viewed from the direction parallel to the axial direction of the turbine wheel 24. In that case, two scroll flow paths 21 and 22 that are divided from each other are provided corresponding to each of the first and second cylinders. Exhaust gas from the first cylinder flows into the scroll passage 21, and exhaust gas from the second cylinder flows into the scroll passage 22. The communication control valve 28 includes a communication state (open state shown in FIG. 6) in which the plurality of scroll channels 21, 22 and the communication chamber 25 communicate with each other upstream from the nozzle 26, and a plurality of scrolls upstream from the nozzle 26. It is possible to selectively switch to a cut-off state (closed state shown in FIG. 8) in which the communication between the flow paths 21 and 22 and the communication chamber 25 is cut off. When the communication control valve 28 is in a communication state, as shown in FIG. 6, the plurality of scroll passages 21 and 22 communicate with each other via the communication chamber 25 on the upstream side of the nozzle 26. On the other hand, when the communication control valve 28 is in the shut-off state, as shown in FIG. 8, the communication between the plurality of scroll channels 21 and 22 on the upstream side of the nozzle 26 is shut off.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to such embodiment at all, and it can implement with a various form in the range which does not deviate from the summary of this invention. Of course.

It is a figure showing a schematic structure of a supercharged engine system provided with a turbocharger concerning an embodiment of the present invention. It is a figure which shows the outline of the internal structure of the turbocharger which concerns on embodiment of this invention. It is a figure which shows the outline of the internal structure of the turbocharger which concerns on embodiment of this invention. It is a figure which shows the outline of the internal structure of the turbocharger which concerns on embodiment of this invention. It is a figure explaining operation | movement of the supercharged engine system which concerns on embodiment of this invention. It is a figure which shows the outline of the other internal structure of the turbocharger which concerns on embodiment of this invention. It is a figure which shows the outline of the other internal structure of the turbocharger which concerns on embodiment of this invention. It is a figure which shows the outline of the other internal structure of the turbocharger which concerns on embodiment of this invention.

Explanation of symbols

  1-3 cylinders, 10 internal combustion engines, 12 turbochargers, 13 intercoolers, 17 shafts, 18 compressors, 19 compressor wheels, 20 turbines, 21-23 scroll channels, 24 turbine wheels, 25 communication chambers, 26 nozzles, 28 Communication control valve, 31-33 Exhaust passage.

Claims (4)

A turbocharger that pressurizes intake air into an engine by using exhaust energy of engines having different pulsation phases generated in exhaust gases from a plurality of cylinders,
A plurality of scroll channels provided for each cylinder of the engine, each of which has a plurality of scroll channels into which exhaust gas from each cylinder flows,
A nozzle into which exhaust gas from a plurality of scroll passages flows;
A turbine wheel that rotates using the energy of the exhaust gas supplied through the nozzle;
A compressor that pressurizes intake air into the engine using the rotational power of the turbine wheel;
Communication that can be selectively switched between a communication state in which a plurality of scroll flow paths communicate with each other on the upstream side of the nozzle and a blocking state in which communication between the plurality of scroll flow paths on the upstream side of the nozzle is blocked. A control valve;
Have
When the communication control valve is in the communication state, the exhaust gas that has flowed into each scroll channel from each cylinder interferes with each other and is supplied to the nozzle.
A turbocharger in which, when the communication control valve is in a shut-off state, exhaust gases respectively flowing into the scroll flow paths from the cylinders are supplied to the nozzles without interfering with each other. The turbocharger according to claim 1,
A communication chamber for communicating the plurality of scroll channels on the upstream side of the nozzle with each other;
The communication control valve has a communication state in which the plurality of scroll passages and the communication chamber communicate with each other upstream from the nozzle, and a blocking state in which communication between the plurality of scroll passages and the communication chamber on the upstream side from the nozzle is interrupted, Turbocharger that can be selectively switched to. The turbocharger according to claim 1 or 2,
The communication control valve is selectively switched between a communication state and a shut-off state according to the engine speed.
A turbocharger in which an engine speed when the communication control valve is in a communication state is higher than an engine speed when the communication control valve is in a shut-off state. An engine having different pulsation phases in exhaust gases from a plurality of cylinders,
A turbocharger that pressurizes intake air into the engine using the exhaust energy of the engine;
A supercharged engine system comprising:
The supercharged engine system whose said turbocharger is the turbocharger of any one of Claims 1-3.

Images