JP2015010557A - Exhaust turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust turbocharger for controlling a waste gate valve using positive pressure air, and is configured to ensure the control of the waste gate valve using a small amount of air.SOLUTION: In a compressor housing (a suction-side side housing 6) 11, an annular scroll passage 21 is formed to compress air with the rotation of a compressor vane 10. The scroll passage 21 has the cross section area gradually increased from a starting end 21a toward a finishing end 21b, and the starting end 21a and the finishing end 21b are communicated with each other via a tongue part 25 with a small width. A positive pressure air takeout port 17 for driving the waste gate valve is provided around the axial core of an air outlet 5 at a portion 26 encircling the tongue part 25. Since the pressure of air is the highest at the finishing end 21b of the scroll passage 21, the waste gate valve 15 can be accurately controlled.

Description

  The present invention relates to an exhaust turbocharger in which a wastegate valve is driven by positive pressure air.

  The exhaust turbocharger is provided with a wastegate valve, and is set so that the wastegate valve is opened when the intake pressure reaches a predetermined pressure in order to prevent supercharging. The positive pressure of the intake air is used as a power source for the actuator that drives the wastegate valve, and examples thereof are disclosed in Patent Documents 1 and 2.

  Of these, in Patent Document 1, a positive-pressure air outlet for driving the actuator is provided in a portion of the intake system close to the cylinder. On the other hand, in Patent Document 2, the air outlet for driving the actuator is provided with an exhaust turbocharger. The compressor housing in the supercharger is provided in the middle of the scroll passage.

Japanese Utility Model No. 63-126524 Microfilm A microfilm of Japanese Utility Model Application No. 60-114237

  In order to drive the actuator accurately and responsively, it is preferable that the pressure of the positive pressure air as a drive source is as high as possible. However, in the configuration of taking out from the vicinity of the cylinder in the intake system as in Patent Document 1, flow resistance or the like Since it takes out from the part where the pressure of air (intake air) has dropped, there is a risk that the drive of the actuator will be incomplete, and if the amount of air taken out is increased in order to drive the actuator accurately, it will go to the cylinder There is a problem that the intake air amount is reduced and the power fluctuation of the engine is increased.

  On the other hand, since the pressure of the compressor housing of the exhaust turbocharger is the highest in the entire intake system, it is reasonable to take out drive air from the scroll passage in the compressor housing as in Patent Document 2.

  However, if it is taken out from the middle part between the start end and the end of the scroll passage as in Patent Document 2, a part of the air flowing in the circumferential direction in the scroll passage disappears, so that the air flow is disturbed and the compression efficiency is increased. May get worse. In the scroll passage, the pressure gradually increases from the start to the end, but the pressure is still in the middle of the scroll passage, so the positive pressure generated by the exhaust turbocharger is effectively used. However, there is still room for improvement.

  The present invention has been made in view of the current situation, and taking out the driving air of the wastegate valve from the exhaust turbocharger itself follows the Patent Document 2, while providing an exhaust turbocharger with an improved configuration. It is to be provided.

  The exhaust turbocharger according to the present invention includes an exhaust turbine blade driven by exhaust gas, a wastegate valve that adjusts an amount of exhaust gas directed to the exhaust turbine blade, and a compressor blade driven by the exhaust turbine blade. The compressor has a built-in compressor housing, and the wastegate valve is driven by positive pressure air generated in the compressor housing.

  In the first aspect of the present invention, the compressor housing includes an air intake opening in which air is opened in a rotation axis direction of the compressor blades, a compressor chamber in which the compressor blades are disposed and communicated with the air intake port, and the compressor chamber An annular scroll passage that communicates with the outer peripheral portion of the scroll passage, and an air outlet that communicates with the end of the scroll passage, and the scroll passage of the compressor housing. A positive air outlet for controlling the wastegate valve is provided at a portion surrounding the terminal portion and corresponding to the tongue portion.

  According to a second aspect of the present invention, in the first aspect, the positive pressure air outlet is provided on an outer peripheral portion opposite to the tongue portion with the terminal end portion of the scroll passage interposed therebetween.

  In the exhaust turbocharger, as the compressor blades rotate, the air sucked from the intake port moves in the circumferential direction inside the scroll passage while being pushed in the radial direction, and the air is collected in the scroll passage and exited. To. And since the start end and the end of the scroll passage communicate with each other through a narrow tongue to impart a flow of rotation to the air, the amount of air reaching the air outlet is slightly less than the end of the scroll passage. Therefore, the air pressure is highest at the end portion of the scroll passage.

  And since this invention takes out air from the part where pressure is the highest, it can drive an actuator exactly with as little air quantity as possible. In addition, the end of the scroll passage communicates with the air outlet, and the air flows straight toward the air outlet, so that even if a part of the air is taken out, the air flow flowing through the scroll passage changes as a pressure fluctuation. There is no impact. Therefore, the influence of taking out the air does not spread to the rotation of the compressor blades and the compression efficiency does not deteriorate.

  As described above, according to the present invention, the actuator can be driven by taking out air from a portion having the highest pressure without affecting the rotation of the compressor blade.

  The air is given kinetic energy by the compressor blades and flows in the circumferential direction inside the scroll passage. However, since centrifugal force acts on the air, the dynamic pressure of the air is generated by the compressor blades on the inner surface of the scroll passage. It acts most strongly on the outer peripheral portion farthest from the shaft center, and therefore the pressure is highest in the outer peripheral portion on the side opposite to the tongue portion among the end portions of the scroll passage. Therefore, if the structure of Claim 2 is employ | adopted, since air can be taken out from the outer peripheral part with especially high pressure also in a termination | terminus part, there exists an advantage which can drive an actuator more correctly.

It is a figure which shows embodiment, (A) is a typical top view, (B) is a vertical front view of the principal part. FIG. 1 (B) is a partially broken view IIA-IIA, and FIG. It is the III-III sectional view taken on the line of FIG. (A) is a cross-sectional view taken along the line IVA-IVA in FIG. 2 (A), and (B) is a cross-sectional view taken along the line IVB-IVB in FIG. 2 (A).

(1). Outline Next, an embodiment of the present invention will be described with reference to the drawings. As schematically shown in FIG. 1A, the exhaust turbocharger has an exhaust side housing 3 having an exhaust gas inlet 1 and an exhaust gas outlet 2, an intake port 4 and an air outlet 5. The intake side housing 6 and the side housings 3 and 6 have a center housing 7 joined from the left and right by bolting or the like.

  An exhaust turbine blade 1 is rotatably disposed in a turbine chamber surrounded by the exhaust side housing 3 and the center housing 7, and a compressor chamber 9 formed by the intake side housing 6 and the center housing 7 is provided in the compressor chamber 9. A compressor blade 10 is rotatably arranged.

  Therefore, the entire intake side housing 6 and a part of the center housing 7 constitute the compressor housing 11 described in the claims. Further, the exhaust side housing 3 and the center housing 7 constitute a turbine housing 12. The exhaust turbine blade 1 and the compressor blade 10 are connected by a common rotating shaft 13 so as to rotate together.

  The exhaust gas inlet 1 of the exhaust side housing 3 and the air outlet 5 of the intake side housing 6 open in a direction orthogonal to the rotation shaft 13, and the exhaust gas outlet 2 of the exhaust side housing 3 and the intake side The intake port 4 of the housing 6 is opened in the axial direction of the rotary shaft 13. The exhaust turbine blade 1 and the compressor blade 10 have a plurality of fins extending in the radial direction and the circumferential direction.

  The exhaust side housing 3 is provided with a bypass passage 14 for allowing exhaust gas to escape from the exhaust inlet 1 to the exhaust outlet 2 and a wastegate valve 15 for adjusting both of the exhaust gas flowing from the exhaust inlet 1 to the bypass passage 14. ing. The waste gate valve 15 includes an actuator 16 driven by positive pressure air, and the actuator 16 is driven by positive pressure air taken out from the compressor housing 10. Therefore, a positive pressure air outlet 17 is provided in the intake side housing 6 and the actuator 16 is connected to a pipe 18 such as a tube.

  As shown in FIG. 1B, the intake side housing 6 is formed with a recess 20 into which the center housing 7 is fitted, and an annular scroll passage 21 positioned outside the outer periphery of the compressor blade 10. An outer peripheral portion 9a of the compressor chamber 9 is present in a ring shape between a portion of the intake side housing 6 inside the scroll passage 21 and the center housing 7, and the scroll passage 21 is formed as a whole. Thus, it communicates with the outer peripheral portion 9 a of the compressor chamber 9.

  A fixed bearing 22 is fitted to the inner periphery of the center housing 7, and a movable bearing 22 ′ is fitted to the inner periphery of the fixed bearing 22 via a seal material. The movable bearing 23 is fixed to the rotating shaft 13.

(2). Scroll passage / positive air outlet As shown in FIG. 2, the air outlet 5 is provided integrally with the outlet side housing 6, and the axis 23 of the air outlet 5 is substantially the same as one tangent of the scroll passage 21. I'm doing it. In other words, the airflow that has flowed through the scroll passage 21 flows into the air outlet 5 that is guided so as to advance straight in one tangential direction of the scroll passage 21.

  The scroll passage 21 roughly has a cross-sectional shape close to a circle, and the inner peripheral portion on the side close to the center housing 7 is an annular bank 24. In other words, by forming the bank 24 on the inner periphery, the cross-sectional shape of the scroll passage 21 is substantially circular.

  The cross-sectional shape of the scroll passage 21 gradually increases from the start end portion 21a toward the end portion 21b. However, the start end portion 21a and the end end portion 21b of the scroll passage 21 are located at portions close to the air outlet 5. It communicates in series via the tongue 25. Accordingly, a part of the compressed air flowing through the scroll passage 21 returns to the scroll passage 21 again via the tongue 25. Thereby, a smooth air flow can be formed inside the scroll passage 21.

  To be precise, the tongue portion 25 is formed at an extended position of a portion of the inner peripheral surface of the air outlet 5 that is closest to the axial center of the intake port 4. For this reason, most of the air flowing into the scroll passage 21 is smoothly guided to the air outlet 5 without colliding with the tongue portion 25.

  A positive pressure air outlet 17 is provided in a portion 26 of the intake side housing 6 surrounding the end portion 21 b of the scroll passage 21. The positive-pressure air outlet 17 is formed in an outward boss shape, and an outlet hole 27 is provided in the positive-pressure air outlet 17 to fit the joint cylinder 28. A pipe line 18 (see FIG. 1A) such as a tube is connected to the joint cylinder 28.

  The outlet hole 27 of the positive pressure air outlet 17 is open in the same direction as the inlet 4 in the examples of FIGS. 2A and 3. In the example shown in FIG. It opens in a direction perpendicular to the center and toward the opposite side of the tongue 25 with the axis 23 of the air outlet 5 interposed therebetween. That is, in the example of FIG. 2B, the air outlet 5 is opened toward the tongue portion 25 approximately.

  The rotation of the compressor blade 10 causes air (fresh air) to be sucked from the intake port 4 and sent toward the scroll passage 21, and the air flows from each part of the entire circumference into the scroll passage 21 and flows toward the air outlet 5. However, the pressure is highest at the location of the end portion 21b of the scroll passage 21 (that is, the location of the tongue portion 25). For this reason, the actuator 16 can be accurately controlled with a small amount of air.

  Further, even if a part of the air is taken out from the end portion 21 b of the scroll passage 21, pressure fluctuation does not occur inside the scroll passage 21, so that the compression efficiency is attributed to the fact that the air is taken out from the positive pressure air outlet 17. Will not get worse or fluctuate.

  Since air is pushed from the start end 21a toward the end portion 21b inside the scroll passage 21, the pressure gradually increases from the start end 21a toward the end portion 21b, but centrifugal force acts on the air. Therefore, when viewed at an arbitrary point in the scroll passage 21, the pressure on the outer peripheral side far from the compressor blade 10 is higher than the inner peripheral side near the compressor blade 10. When it sees, the site | part of the outer peripheral part on the opposite side to the tongue part 25 among the termination | terminus parts 21b has the highest pressure.

  Therefore, as shown in FIG. 2B (as in claim 2), if the positive pressure air outlet 17 is opened on the opposite side of the tongue 25 across the axis 23 of the air outlet 5, less air is required. It is possible to more reliably drive the actuator 16 accurately.

  On the other hand, since air flows into the inside of the scroll passage 21 from the outer peripheral portion 9a of the compressor chamber 9, the air flows so as to swirl inside the scroll passage 21, so that the pressure (dynamic pressure) of the air is The kinetic energy decreases as the distance from the outer peripheral portion 9a (or the center housing 7) of the compressor chamber 9 starts at the outer peripheral portion of the scroll passage 21.

  Then, the pulsation accompanying the opening and closing of the exhaust valve is generated in the exhaust gas, and the pulsation may spread to the compressor blades 10, and the pulsation may remain in the air flowing into the scroll passage 21, but FIG. As shown in FIG. 3, when the positive pressure air outlet 17 is provided on the side opposite to the outer peripheral portion 9 a of the compressor chamber 9 with the scroll passage 21 interposed therebetween, the air whose dynamic pressure is reduced and pulsation is attenuated can be extracted. Therefore, there is an advantage that it is possible to prevent or suppress the pulsation from spreading to the actuator 16.

  The present invention is actually applicable to an exhaust turbocharger of an internal combustion engine. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Exhaust turbine 3 Exhaust side housing 4 Intake port 5 Air outlet 6 Intake side housing 7 Center housing 9 Compressor chamber 10 Compressor blade 11 Compressor housing 12 Turbine housing 13 Rotating shaft 14 Bypass passage 15 Westgate valve 16 Actuator 17 Positive pressure air Take-out port 21 Scroll passage 23 Axial center line of air outlet 25 Tongue portion 26 A portion surrounding the end portion of the scroll passage

Claims (2)

An exhaust turbine blade driven by exhaust gas, a wastegate valve for adjusting the amount of exhaust gas directed to the exhaust turbine blade, and a compressor housing in which a compressor blade driven by the exhaust turbine blade is built-in The wastegate valve is driven by positive pressure air generated in the compressor housing,
The compressor housing includes an intake port that opens air in a rotation axis direction of the compressor blade, a compressor chamber in which the compressor blade is disposed and communicated with the intake port, a communication chamber that communicates with an outer peripheral portion of the compressor chamber, and a start end An annular scroll passage that communicates with the end of the scroll passage through the tongue, and an air outlet that communicates with the end of the scroll passage;
A portion of the compressor housing that surrounds the end portion of the scroll passage and a portion corresponding to the tongue portion is provided with a positive pressure air outlet for controlling the wastegate valve.
Exhaust turbocharger. The outlet port for the positive pressure air is provided on the outer peripheral portion on the opposite side of the tongue portion across the terminal end portion of the scroll passage.
The exhaust turbocharger according to claim 1.

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