JP4441349B2 - Turbocharger and turbine - Google Patents

Description

  The present invention relates to a turbocharger and a turbine in which a turbine wheel is rotationally driven by gas in a turbine scroll flowing into a flow path between blades of the turbine wheel through a nozzle.

  An example of a conventional turbocharger is disclosed in Patent Document 1 below. The turbine of the turbocharger in Patent Document 1 is a twin scroll type turbine. As shown in FIG. 12, the interior of the turbine scroll 109 to which engine exhaust gas is supplied is separated by a partition wall 111 in the axial direction of the turbine wheel 114. The passage is divided into a first passage 110a and a second passage 110b. A bladed nozzle 112a is provided at the outlet of the first passage 110a, and the exhaust gas supplied to the first passage 110a passes through the bladed nozzle 112a to the inlet 113 of the inter-blade flow path of the turbine wheel 114. Inflow. On the other hand, a vaneless nozzle 112b is provided at the outlet of the second passage 110b, and the exhaust gas supplied to the second passage 110b passes through the vaneless nozzle 112b and enters the inlet of the flow path between the blades of the turbine wheel 114. It flows into 113. Further, a control valve 117 capable of opening and closing the second passage 110b is provided at the inlet of the second passage 110b.

  During low-speed operation of the engine, the second passage 110b is closed by the control valve 117, so that the exhaust gas of the engine is supplied only to the first passage 110a and flows between the blades of the turbine wheel 114 through only the bladed nozzle 112a. It flows into the entrance 113 of the road. Here, the supercharging pressure during low-speed operation of the engine is increased by setting the shape of the bladed nozzle 112a so as to provide a sufficiently high-speed flow even with a small exhaust flow rate. On the other hand, at the time of high-speed operation of the engine, the second passage 110b is opened by the control valve 117, so that the engine exhaust gas is supplied to both the first passage 110a and the second passage 110b, and the bladed nozzle 112a and the bladeless It flows into the inlet 113 of the flow path between the blades of the turbine wheel 114 through both of the nozzles 112b. As a result, the supercharging pressure during high-speed operation of the engine is suppressed, and the engine back pressure (turbine inlet pressure) is reduced.

  In addition, the turbochargers disclosed in Patent Documents 2 to 5 below are disclosed.

Japanese Patent Laid-Open No. 60-166718 Japanese Patent Publication No. 7-13467 JP 2004-68631 A JP-A-5-149144 JP-A-6-185371

  In Patent Document 1, as shown in FIG. 12, the nozzle is divided into a bladed nozzle 112 a and a bladeless nozzle 112 b at the inlet 113 of the inter-blade flow path of the turbine wheel 114. When the second passage 110b is closed by the control valve 117, the engine exhaust gas does not pass through the bladeless nozzle 112b but passes through only the bladed nozzle 112a as shown by the arrow in FIG. It flows into the inlet 113 of the inter-blade channel. In that case, as shown in FIG. 12, in the flow path between the blades of the turbine wheel 114, the flow of the exhaust gas is uneven, and there is a region 115 where the exhaust gas does not flow. Therefore, a vortex is generated in the region 115 where the exhaust gas in the inter-blade flow path does not flow, and the loss of the turbine increases. Therefore, Patent Document 1 has a problem that it is difficult to achieve high efficiency of the turbine over a wide operation region.

  An object of this invention is to provide the turbocharger and turbine which can implement | achieve high efficiency over a wide operation area | region.

A turbocharger according to the present invention is a turbocharger in which a gas in a turbine scroll flows into a passage between blades of a turbine wheel through a nozzle, whereby the turbine wheel is rotationally driven to perform supercharging. The nozzle includes a first nozzle that guides the gas in the turbine scroll to the inlet of the inter-blade channel, and a second nozzle that guides the gas in the turbine scroll to the middle part of the inter-blade channel. A control valve is provided between the turbine scroll and the second nozzle, and the opening between the turbine scroll and the second nozzle is adjusted by the control valve, whereby the first valve The gist is that the flow rate of the gas passing through the two nozzles can be adjusted.

  In the turbocharger according to the present invention, the flow path width in the turbine wheel axial direction of the first nozzle is set to be substantially equal to the flow path width in the turbine wheel axial direction of the inlet of the inter-blade flow path. You can also

  In the turbocharger according to the present invention, the turbine scroll may be a non-split type scroll in which a partition wall for dividing the flow path is not provided.

  In the turbocharger according to the present invention, the flow passage area of the second nozzle may be set larger than the flow passage area of the first nozzle.

  In the turbocharger according to the present invention, fixed blades may be provided on at least one of the first nozzle and the second nozzle.

  In the turbocharger according to the present invention, the second nozzle is provided with movable vanes, and the opening of the second nozzle is adjusted by the movable vanes so that the flow rate of the gas passing through the second nozzle is reduced. Adjustments can also be possible.

The turbine according to the present invention is a turbine in which the turbine wheel is rotationally driven by the gas in the turbine scroll flowing into the inter-blade flow path of the turbine wheel through the nozzle. a first nozzle for guiding a gas to the inlet of the blade between the flow passage, a second nozzle for directing gas in a turbine scroll to the middle portion of the blade between the flow path, is provided with the a turbine scroll the A control valve is provided between the two nozzles, and by adjusting the opening between the turbine scroll and the second nozzle by the control valve , the flow rate of the gas passing through the second nozzle can be adjusted. The gist is that it is possible.

  According to the present invention, the first nozzle that guides the gas in the turbine scroll to the inlet of the passage between the blades of the turbine wheel, and the second nozzle that guides the gas in the turbine scroll to the middle part of the passage between the blades of the turbine wheel; By adjusting the flow rate of the gas passing through the second nozzle, high efficiency of the turbine can be realized over a wide operation region.

  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 to 4 are diagrams showing an outline of a configuration of a turbocharger including a turbine according to an embodiment of the present invention. FIG. 1 shows an internal configuration of the turbine 10 viewed from a direction perpendicular to the turbine wheel 14 axial direction. FIG. 2 shows the internal configuration of the turbine 10 as seen from the direction parallel to the axial direction of the turbine wheel 14. 3 is a perspective view of the internal configuration of the turbine 10, and FIG. 4 is an enlarged view of the nozzle and the turbine wheel 14 in FIG. However, in FIG. 2, illustration of the turbine wheel 14 is omitted. The turbocharger according to the present embodiment is used for supercharging an engine, for example.

  Exhaust gas from an engine (not shown) is supplied into the turbine scroll 12 through an exhaust pipe (not shown). Exhaust gas in the turbine scroll 12 flows into the inter-blade flow path of the turbine wheel 14 through a nozzle having a configuration described later, whereby the turbine wheel 14 is rotationally driven. The turbine wheel 14 is connected to a compressor wheel (not shown) via a rotating shaft 16, and the compressor wheel is rotationally driven together with the rotational driving of the turbine wheel 14. By rotating the compressor wheel, the intake gas can be pressurized and supplied to the intake port (not shown) of the engine. As a result, the engine can be supercharged.

  In the present embodiment, the turbine scroll 12 is a non-split type scroll that is not provided with a partition wall that divides the flow path. As a nozzle that guides the exhaust gas in the turbine scroll 12 to the inter-blade passage of the turbine wheel 14, a first nozzle 22 that guides the exhaust gas to the inlet 13 of the inter-blade passage of the turbine wheel 14, A second nozzle 24 is provided that is disposed at a predetermined distance in the axial direction of the turbine wheel 14 and guides the exhaust gas to the midway portion 15 of the flow path between the blades of the turbine wheel 14. Here, as shown in FIG. 4, the distance between the intermediate portion 15 of the inter-blade flow path and the rotational axis center of the turbine wheel 14 is greater than the distance between the inlet 13 of the inter-blade flow path and the rotational axis center of the turbine wheel 14. The distance r2 between the second nozzle 24 and the rotation axis center of the turbine wheel 14 is set to be smaller than the distance r1 between the first nozzle 22 and the rotation axis center of the turbine wheel 14. The flow path width b1 of the first nozzle 22 in the axial direction of the turbine wheel 14 is set substantially equal to the flow path width b3 of the inlet 13 of the inter-blade flow path in the axial direction of the turbine wheel 14.

  The first nozzle 22 is provided with a plurality of fixed vanes 28, and the second nozzle 24 is provided with a plurality of fixed vanes 30. Here, as shown in FIG. 4, the flow path width b2 of the second nozzle 24 in the axial direction of the turbine wheel 14 is set to be larger than the flow path width b1 of the first nozzle 22 in the axial direction of the turbine wheel 14, The flow area of the nozzle 24 is set larger than the flow area of the first nozzle 22. As a typical example, the flow area of the second nozzle 24 is preferably about 3 to 4 times the flow area of the first nozzle 22.

  Further, a control valve 26 is provided between the turbine scroll 12 and the second nozzle 24. The flow rate of the exhaust gas passing through the second nozzle 24 can be adjusted by adjusting the opening degree (flow path area) between the turbine scroll 12 and the second nozzle 24 by the control valve 26.

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

  During low-speed operation of the engine, the communication between the inside of the turbine scroll 12 and the second nozzle 24 is blocked by closing the control valve 26. Thereby, the flow of the exhaust gas from the second nozzle 24 to the midway part 15 of the inter-blade flow path is blocked. At this time, the exhaust gas in the turbine scroll 12 passes through only the first nozzle 22 and flows into the inter-blade passage of the turbine wheel 14 only from the inlet 13 of the inter-blade passage. Here, the flow area of the first nozzle 22 and the shape of the fixed vane 28 are set in accordance with the low speed region of the engine so that a sufficiently high speed flow can be obtained even with a small exhaust gas flow rate. The supercharging pressure can be increased.

  In the present embodiment, the exhaust gas flowing from the inlet 13 of the inter-blade passage through the first nozzle 22 flows through almost the entire region in the inter-blade passage of the turbine wheel 14 during low-speed operation of the engine. The generation of vortices due to the existence of the region where the exhaust gas does not flow is prevented. Therefore, when the engine is operating at low speed, the efficiency of the turbine 10 can be improved by suppressing the loss of the turbine 10 due to the generation of vortices, and the turbine 10 inlet pressure (engine back pressure) can be reduced.

  On the other hand, when the engine is operating at high speed, the control valve 26 is opened to allow the inside of the turbine scroll 12 and the second nozzle 24 to communicate with each other. Thereby, the flow of the exhaust gas from the second nozzle 24 to the midway part 15 of the inter-blade channel is allowed. At this time, the exhaust gas in the turbine scroll 12 flows into the inter-blade channel of the turbine wheel 14 from the inlet 13 of the inter-blade channel through the first nozzle 22 and flows between the blades through the second nozzle 24. It flows into the inter-blade flow path of the turbine wheel 14 from the middle part 15 of the road. Thereby, even if the exhaust gas flow rate increases, the rotation speed of the turbine wheel 14 can be suppressed, and the supercharging pressure during high-speed operation of the engine can be suppressed. Then, by setting the flow area of the second nozzle 24 to be larger than the flow area of the first nozzle 22, it is possible to realize a nozzle flow area suitable for high-speed operation of the engine. Furthermore, by controlling the opening degree of the control valve 26, the flow rate of the exhaust gas passing through the second nozzle 24 can be controlled, and the supercharging pressure of the engine can be controlled.

  In the present embodiment, the exhaust gas passing through the second nozzle 24 flows into the inter-blade passage of the turbine wheel 14 from the midway portion 15 of the inter-blade passage during high-speed operation of the engine. Since the exhaust gas passing through can be used for rotational driving of the turbine wheel 14, the exhaust energy recovery efficiency is increased. Therefore, the efficiency of the turbine 10 can be improved during high-speed operation of the engine, and the turbine 10 inlet pressure (engine back pressure) can be reduced.

  In the above description of the operation, it can be determined that the engine is operating at a low speed when the rotational speed of the engine is equal to or lower than a threshold value, and it can be determined that the engine is operating at a high speed when the rotational speed of the engine is greater than the threshold value. The control valve 26 can be driven by an actuator (not shown), for example. Alternatively, for example, as in Patent Document 1, the compressor outlet pressure (supercharging pressure) can be used to drive the control valve 26. When the compressor outlet pressure is a predetermined value or less, the control valve 26 is closed, and the compressor outlet pressure ( The control valve 26 may be configured to open when the supercharging pressure is greater than a predetermined value.

  As described above, in the present embodiment, it is possible to achieve high efficiency of the turbine 10 over a wide operation region, and to reduce the turbine 10 inlet pressure (engine back pressure) over a wide operation region. Can do. As a result, the fuel efficiency of the engine can be improved.

  Hereinafter, another example of the present embodiment will be described with reference to FIGS. However, illustration of the turbine wheel 14 is omitted in FIGS.

  In the above description, the case where the fixed vanes 28 and 30 are provided in both the first nozzle 22 and the second nozzle 24 has been described. However, in the present embodiment, as shown in the internal configuration diagram of the turbine 10 in FIGS. 5 and 6, the fixed vane 28 is provided only on the first nozzle 22, and the fixed vane 30 of the second nozzle 24 is omitted. You can also. Further, although not shown, the fixed vanes 28 and 30 may be omitted for both the first nozzle 22 and the second nozzle 24.

  In the present embodiment, as shown in the internal configuration diagram of the turbine 10 in FIGS. 7 and 8, a plurality of control valves 26 capable of adjusting the flow rate of the exhaust gas passing through the second nozzle 24 may be provided. 7 and 8, the plurality of control valves 26 are connected to each other via a link mechanism 34 and can be simultaneously driven by, for example, an actuator (not shown).

  In the present embodiment, as shown in the internal configuration diagram of the turbine 10 in FIGS. 9 and 10, a plurality of movable vanes 32 are provided in the second nozzle 24 instead of the plurality of fixed vanes 30, and the control valve 26 is provided. It can be omitted. The plurality of movable vanes 32 are connected to each other via a link mechanism 34 and can be simultaneously driven by an actuator (not shown), for example. By adjusting the opening degree (flow channel area) of the second nozzle 24 by adjusting the angle of the movable vane 32, the flow rate of the exhaust gas passing through the second nozzle 24 can be adjusted.

  In the configuration shown in FIGS. 9 and 10, the second nozzle 24 is closed by the movable vane 32 (or the opening of the second nozzle 24 is reduced) during low-speed operation of the engine. On the other hand, the second nozzle 24 is opened by the movable vane 32 (or the opening degree of the second nozzle 24 is increased) during high-speed operation of the engine. Further, the angle of the movable vane 32 may be controlled so that the opening degree (flow path area) of the second nozzle 24 increases as the rotational speed of the engine increases.

  Here, FIG. 11 shows the effect of reducing the turbine 10 inlet pressure (engine back pressure) in each configuration example of the present embodiment. 11, the first embodiment has the configuration shown in FIGS. 1 to 4 in which the control valve 26 and the fixed vanes 28 and 30 are provided. In the second embodiment, the control valve 26 and the fixed vane 28 are provided, and the fixed vane 30 is omitted. In the third embodiment, the control valve 26 is provided and the fixed vanes 28 and 30 are omitted. In the fourth embodiment, the fixed vane 28 and the movable vane 32 are provided, and the control valve 26 is omitted. 10 configurations. In the conventional example, when the rotational speed of the engine is larger than the threshold value, the waste gate valve is opened to let the exhaust gas at the turbine inlet escape to the turbine outlet. Further, in each example of FIG. 11, when the engine speed is larger than the threshold value, the control valve 26 (in the case of the first to third examples, the fourth example is used so that the supercharging pressure of the engine becomes a predetermined value). The opening degree of the movable vane 32, which is a waste gate valve in the conventional example, is controlled.

  As shown in FIG. 11, according to Examples 1-4, it turns out that the turbine 10 inlet pressure (engine back pressure) can be reduced rather than the prior art example. That is, according to Examples 1-4, it turns out that the efficiency of the turbine 10 can be improved.

  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 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 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 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. 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. It is a figure explaining the reduction effect of the turbine inlet pressure by the turbocharger concerning the embodiment of the present invention. It is a figure explaining the outline of the internal structure of the conventional turbocharger, and its problem.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Turbine, 12 Turbine scroll, 13 Inlet of flow path between blades, 14 Turbine wheel, 15 Middle part of flow path between blades, 16 Rotating shaft, 22 1st nozzle, 24 2nd nozzle, 26 Control valve, 28, 30 Fixed Vane, 32 Movable vane.

Claims (6)

A turbocharger in which the gas in the turbine scroll flows into the flow path between the blades of the turbine wheel through the nozzle so that the turbine wheel is rotationally driven to perform supercharging.
As the nozzle, a first nozzle that guides the gas in the turbine scroll to the inlet of the inter-blade flow path, and a second nozzle that guides the gas in the turbine scroll to the middle part of the inter-blade flow path are provided. ,
A control valve is provided between the turbine scroll and the second nozzle;
A turbocharger characterized in that the flow rate of gas passing through the second nozzle can be adjusted by adjusting the opening between the turbine scroll and the second nozzle by the control valve . The turbocharger according to claim 1,
The turbocharger, wherein a flow path width in the turbine wheel axial direction of the first nozzle is set to be substantially equal to a flow path width in the turbine wheel axial direction of an inlet of the inter-blade flow path. The turbocharger according to claim 1 or 2,
The turbocharger is a turbocharger characterized in that the turbine scroll is a non-dividing scroll in which a partition wall for dividing a flow path is not provided. The turbocharger according to any one of claims 1 to 3,
The turbocharger, wherein a flow area of the second nozzle is set larger than a flow area of the first nozzle. The turbocharger according to any one of claims 1 to 4,
A turbocharger, wherein fixed blades are provided on at least one of the first nozzle and the second nozzle. A turbine in which the turbine wheel is driven to rotate by the gas in the turbine scroll flowing through the nozzle into the flow path between the blades of the turbine wheel,
As the nozzle, a first nozzle that guides the gas in the turbine scroll to the inlet of the inter-blade flow path, and a second nozzle that guides the gas in the turbine scroll to the middle part of the inter-blade flow path are provided. ,
A control valve is provided between the turbine scroll and the second nozzle;
A turbine characterized in that the flow rate of gas passing through the second nozzle can be adjusted by adjusting an opening between the turbine scroll and the second nozzle by the control valve .

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