JP2005207334A - Turbocharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbocharger which is improved in mountability to an engine, while maintaining the function similar to a variable capacity turbocharger having a waste-gate mechanism. <P>SOLUTION: The turbo charger comprises a shaft 50, a compressor rotor 70 mounted on one end of the shaft, a compressor housing 10 holding the compressor rotor, and having an intake-gas inlet 12 and an outlet, a turbine rotor 80 mounted on one end of the shaft, a turbine housing 60 holding the turbine rotor, and having an exhaust-gas inlet and an outlet 64, and a throttle part 90 provided in the pipe line of the turbine-housing outlet so as to throttle the flow-passage of the exhaust gas let out from the turbine-rotor side. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a turbocharger, and more particularly, to a turbocharger capable of improving mountability to an engine while maintaining the same performance as a variable capacity turbocharger having a waste gate mechanism.

  Some turbochargers mainly used for automobiles have a waste gate mechanism that bypasses a part of exhaust gas in order to control the supercharging pressure of the engine. Further, in a variable capacity turbocharger for increasing engine output, the turbine capacity is changed so that a waste gate mechanism is not required. In recent years, energy exceeding the variable capacity is sometimes given to the turbocharger due to the increase in the engine output and the increase in the exhaust gas temperature. Therefore, a variable capacity turbocharger having a wastegate mechanism is also used. As a variable capacity turbocharger having such a wastegate mechanism, for example, the first rod is configured so that only a variable nozzle is opened in a predetermined engine speed range and a wastegate valve (discharge valve) is opened in a higher speed range. There exists what connected the 2nd rod and the link (refer to patent documents 1). In a variable capacity turbocharger with a wastegate mechanism, only the variable nozzle is opened in the specified engine speed range, and energy (exhaust gas) that is unnecessary for supercharging pressure control in the higher speed range is set in the bypass passage. It is led to the outlet side of the turbine through the waste gate valve (see FIG. 5).

JP-A-10-89081

  However, since a variable displacement turbocharger having a conventional wastegate mechanism is equipped with a variable displacement control actuator and a wastegate control actuator, the turbocharger is increased in size to an engine / vehicle. Mounting may be difficult, and there is a problem that control is difficult.

  In addition, when a plurality of control actuators are mounted, there is a problem that the structure becomes complicated and costs increase.

  A first object of the present invention is to provide a turbocharger capable of improving the mountability to an engine while maintaining the same performance as a variable capacity turbocharger having a wastegate mechanism.

  A second object of the present invention is to provide a turbocharger that is simple in structure and low in cost while maintaining the same performance as a variable capacity turbocharger having a wastegate mechanism.

  In the present invention, the turbocharger is a shaft, a compressor rotor attached to one end of the shaft, a compressor housing that houses the compressor rotor, and has an inlet portion and an outlet portion for intake air, and the shaft A turbine rotor attached to one end of the turbine, a turbine housing that houses the turbine rotor and has an inlet portion and an outlet portion for exhaust gas, and a throttle portion that restricts a flow path of the exhaust gas that has passed through the turbine rotor, It is characterized by providing.

  In the turbocharger of the present invention, it is preferable that the throttle portion is disposed in a piping path on the outlet side of the turbine housing.

  In the turbocharger of the present invention, it is preferable that the throttle portion is a plate-like member that is attached to an outlet portion of the turbine housing and has a hole through which exhaust gas flows.

  In the turbocharger of the present invention, it is preferable that the throttle portion has a constant throttle amount.

  In the turbocharger of the present invention, it is preferable not to have a waste gate mechanism for bypassing a part of the exhaust gas from the inlet side to the outlet side of the turbine housing.

  According to the present invention (claims 1-5), while maintaining the same performance as a variable capacity turbocharger having a wastegate mechanism, it is possible to reduce the size and improve the mountability to the engine.

  According to the present invention (claims 1-5), even if there is no waste gate mechanism, the same effect as the variable capacity turbocharger having the waste gate mechanism can be obtained, and the cost can be reduced with a simple structure. be able to.

  A turbocharger according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing the configuration of the turbocharger according to the first embodiment of the present invention.

  The turbocharger 1 includes a compressor housing 10, a bearing housing 30, a turbine housing 60, a compressor rotor 70, a turbine rotor 80, and a throttle unit 90.

  The compressor housing 10 includes a compressor inlet portion 12, a compressor outlet portion (not shown), and a scroll portion 16. The scroll portion 16 is arranged in a spiral shape on the outer periphery of the compressor rotor 70, is configured to gradually increase the cross-sectional area as it approaches the compressor outlet portion, and communicates with the compressor outlet portion.

  The bearing housing 30 is adjacent to the compressor housing 10. A lubricating oil inlet 32 is provided on the outer periphery of the bearing housing 30. The lubricating oil inlet 32 communicates with the branch oil passages 36 and 38 and supplies lubricating oil supplied from an oil pump (not shown) to the shaft 50 and the sliding surface of the bearing 42. The bearing 42 supports the shaft 50. The lubricating oil supplied to the sliding surface is discharged from the lubricating oil outlet 54 through a space 52 formed inside the bearing housing 30.

  The turbine housing 60 is adjacent to the bearing housing 30 and has an exhaust gas inlet portion (not shown) and an exhaust gas outlet portion 64. Further, a scroll portion 66 is formed on the inner peripheral side of the turbine housing 60. The turbine housing 60 does not have a waste gate mechanism for bypassing exhaust gas, and a throttle portion 90 is disposed in the piping path of the exhaust gas outlet portion 64. The restricting portion 90 is a portion that restricts the flow path of the exhaust gas that has passed through the turbine rotor 80, and is arranged at a predetermined position in the piping path of the exhaust gas outlet 64, and the surface of the piping path is raised (streamlined). Shape. The throttle unit 90 is configured integrally with the turbine housing 60. The throttle unit 90 is used in a high-speed rotation region (high flow region) where the exhaust gas needs to be bypassed. The diaphragm unit 90 preferably has a structure that reduces the influence of the diaphragm in the low-speed rotation region as much as possible. Thereby, the supercharging pressure can be controlled by reducing the energy obtained by the turbine rotor 80 in the high-speed rotation region.

  The shaft 50 is supported by the bearing 42 of the bearing housing 30, and the compressor rotor 70 is attached to the end on the compressor housing 10 side so as not to be relatively rotatable, and the turbine rotor 80 is not relatively rotatable at the end on the turbine housing 60 side. Installed on. The compressor rotor 70 is fixed to the shaft 50 by a nut 76 that is screwed into a thread portion formed on the shaft. A compressor blade 72 extending in the radial direction is attached to the compressor rotor 70. Turbine blades 82 extending in the radial direction are attached to the turbine rotor 80. The compressor rotor 70 rotates integrally with the turbine rotor 80 as the turbine rotor 80 rotates.

  According to the above configuration, the wastegate mechanism is not required, and the turbocharger is reduced in size and has a simple structure and low cost while maintaining the same performance as the variable capacity turbocharger having the wastegate mechanism. This improves the mountability to the engine. Moreover, it can be applied to all turbochargers for automobiles.

  Next, the principle of the variable capacity turbocharger according to the first embodiment of the present invention will be described with reference to the drawings while comparing with the variable capacity turbocharger having a conventional wastegate mechanism. FIG. 2 is a schematic diagram illustrating a configuration of a turbo boost pressure control system including the turbocharger according to the first embodiment of the present invention. Refer to FIG. 5 for the configuration of a turbocharging pressure control system including a variable capacity turbocharger having a conventional wastegate mechanism.

  In a turbocharging pressure control system having a variable capacity turbocharger having a conventional wastegate mechanism, referring to FIG. 5, the exhaust gas exhausted from the engine is separated from the turbine side and waste at the turbine inlet in the high speed rotation region. Exhaust gases that have branched and flowed to the gate valve side and passed through the turbine and the waste gate valve merge at the turbine outlet and are discharged to the muffler side. In other words, energy (exhaust gas) that is unnecessary for controlling the compressor outlet pressure P2 (supercharging pressure) in the high-speed rotation region is led to the turbine outlet side through the waste gate valve set in the bypass passage. Yes. On the other hand, in the low-speed rotation region, the exhaust gas exhausted from the engine flows only to the turbine side at the turbine inlet, and the exhaust gas that has passed through the turbine is discharged to the muffler side. In the high-speed rotation region and the low-speed rotation region, the intake air sucked from the compressor inlet 12 is compressed by the compressor rotor 70 by the rotation of the turbine rotor 80, and the intake air having a high density is supplied to the engine.

  In the turbo boost pressure control system including the turbocharger according to the first embodiment, referring to FIG. 2, the exhaust gas exhausted from the engine flows to the turbine in the high speed rotation region, and the exhaust gas that has passed through the turbine is At the outlet of the turbine, the pressure of the exhaust gas is increased on the upstream side of the throttle, and the exhaust is discharged to the muffler. That is, in the high speed rotation region, the compressor outlet pressure P2 (supercharging pressure) is controlled by reducing the energy (exhaust gas) obtained by the turbine by the throttle portion. On the other hand, in the low-speed rotation region, the exhaust gas exhausted from the engine flows to the turbine, and the exhaust gas that has passed through the turbine passes through the throttle portion and is discharged to the muffler side. In the low-speed rotation region, the exhaust gas flow rate is small, so that the exhaust gas pressure does not need to be greatly increased on the upstream side of the throttle section 90, and is greatly different from a turbo boost pressure control system having a variable capacity turbocharger having a wastegate mechanism. There is no. In the high-speed rotation region and the low-speed rotation region, the intake air sucked from the compressor inlet 12 is compressed by the compressor rotor 70 by the rotation of the turbine rotor 80, and the intake air having a high density is supplied to the engine.

  Here, the energy obtained by the turbine is simply calculated by the following equation.

[Equation 1]
W _t = T ・ P ・ Q
W _t : Energy obtained by turbine T: Temperature P: Pressure Q: Exhaust gas flow rate

  According to this equation, the energy obtained by the turbine varies with temperature, pressure, and flow rate. Therefore, in a turbo boost pressure control system including a variable capacity turbocharger having a wastegate mechanism, the flow rate is reduced when the exhaust gas is bypassed, so that the pressure is increased to perform the same work. Note that the temperature can be regarded as unchanged in view of the operating state of the engine when wastegate is performed (high-speed rotation region).

  On the other hand, in the turbocharging pressure control system including the turbocharger according to the first embodiment, there is a concern that the efficiency of the turbocharger may be reduced due to the throttle portion, but the exhaust gas flow rate does not decrease, so that when the exhaust gas is bypassed. No significant pressure increase occurs, only the pressure increase due to the throttle. Therefore, in a situation where the “pressure increase due to the throttle portion” is smaller than the “pressure increase due to the waste gate”, the throttle portion 90 can be set without impairing the efficiency of the turbocharger.

  Next, the compressor outlet pressure P2 (supercharging pressure) characteristics of the turbocharger according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a graph showing the supercharging pressure characteristic of the turbocharger according to the first embodiment of the present invention.

  The measurement conditions were such that a variable capacity turbocharger was used, the exhaust gas flow rate and temperature were constant in the maximum variable capacity state, and only the throttle amount of the throttle part was changed. Referring to FIG. 3, there are shown values obtained by increasing the amount of aperture by the aperture unit to zero, small, medium, and large. It can be seen that the amount of work can be controlled by adjusting the throttle amount of the throttle portion, and the supercharging pressure is changed without bypassing the exhaust gas. That is, if the throttle amount is increased, an increase in supercharging pressure can be suppressed. For example, if it is desired to suppress the supercharging pressure to 5 or less, a turbocharger with a medium or large throttle amount may be selected. If it is desired to suppress the supercharging pressure to 4 or less, a turbocharger having a large throttle amount. It will be sufficient to select.

  Next, a turbocharger according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 4 is a cross-sectional view schematically showing a configuration of the turbocharger according to the second exemplary embodiment of the present invention.

  The turbocharger according to the second embodiment of the present invention is the same as the turbocharger according to the first embodiment except for the configuration of the throttle unit. Referring to FIG. 4, the throttle portion 100 is a plate-like member that is attached to the exhaust gas outlet portion 64 of the turbine housing 60 and has a hole 100 a through which the exhaust gas flows. In FIG. 4, the hole 100 a has only one configuration, but may have a plurality. Even in such a configuration, the waste gate mechanism is not necessary, as in the turbocharger according to the first embodiment, and the size is reduced while maintaining the same performance as the variable capacity turbocharger having the waste gate mechanism. It becomes a turbocharger that also has cost reduction, and improves the mountability to the engine. Moreover, it can be applied to all turbochargers for automobiles.

  In another embodiment of the present invention, the throttle unit of the turbocharger may have a throttle mechanism capable of controlling the throttle amount. In this case, control is performed such that the aperture amount is reduced in the low-speed rotation region and is increased in the high-speed rotation region. According to such a configuration and control, it is possible to suppress the supercharging pressure in the high speed rotation region while increasing the supercharging pressure in the low speed rotation region.

It is sectional drawing which showed typically the structure of the turbocharger which concerns on Embodiment 1 of this invention. It is the schematic which showed the structure of the turbo supercharging pressure control system provided with the turbocharger which concerns on Embodiment 1 of this invention. It is the graph which showed the supercharging pressure characteristic of the turbocharger which concerns on Embodiment 1 of this invention. It is sectional drawing which showed typically the structure of the turbocharger which concerns on Embodiment 1 of this invention. It is the schematic which showed the structure of the turbo supercharging pressure control system provided with the variable capacity | capacitance turbocharger which has the conventional wastegate mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turbocharger 10 Compressor housing 12 Compressor inlet part 16 Scroll part 30 Bearing housing 32 Lubricant oil inlet part 36, 38 Branch oil passage 42 Bearing 50 Shaft 52 Space 54 Lubricant oil outlet part 60 Turbine housing 64 Exhaust gas outlet part 66 Scroll part 70 Compressor rotor 72 Compressor blade 76 Nut 80 Turbine rotor 82 Turbine blade 90, 100 Restriction portion 100a Hole P1 Convolver inlet pressure (engine intake pressure)
P2 compressor outlet pressure (supercharging pressure)
P3 Turbine inlet pressure P4 Turbine outlet pressure (back pressure)

Claims (5)

A shaft,
A compressor rotor attached to one end of the shaft;
A compressor housing that houses the compressor rotor and has an inlet portion and an outlet portion for intake air;
A turbine rotor attached to one end of the shaft;
A turbine housing containing the turbine rotor and having an exhaust gas inlet and outlet;
A throttle part for restricting the flow path of the exhaust gas that has passed through the turbine rotor;
A turbocharger comprising:   The turbocharger according to claim 1, wherein the throttle portion is disposed in a piping path on the outlet side of the turbine housing.   The turbocharger according to claim 1, wherein the throttle portion is a plate-like member that is attached to an outlet portion of the turbine housing and has a hole through which exhaust gas flows.   The turbocharger according to claim 1, wherein the throttle unit has a constant throttle amount.   The turbocharger according to any one of claims 1 to 3, wherein the turbocharger does not have a waste gate mechanism for bypassing a part of the exhaust gas from the inlet side to the outlet side of the turbine housing.

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