WO2006046810A1

WO2006046810A1 - Waste gate unit for turbocharger

Info

Publication number: WO2006046810A1
Application number: PCT/KR2005/003472
Authority: WO
Inventors: Jung Wan Jung
Original assignee: Jung Wan Jung
Priority date: 2004-10-28
Filing date: 2005-10-19
Publication date: 2006-05-04
Also published as: KR20060037719A

Abstract

Disclosed herein is a wastegate unit provided on a turbocharger of an engine. The wastegate unit includes a wastegate valve to selectively close a wastegate which is formed upstream of a turbine of the engine turbocharger and discharges some exhaust gas. A bushing functions to support the wastegate valve and guide the linear motion thereof. An actuator rod is connected to the wastegate valve, and rectilinearly moves the wastegate valve. An actuator functions to operate the actuator rod. The present invention enables the wastegate unit to be easily assembled, thus shortening time required for the assembly process. Further, since the wastegate is opened or closed only by the linear movement of the wastegate valve, the life-span of components is lengthened. The wastegate unit may be applied to a conventional turbocharger without imposing the necessity to change its shape.

Description

Description WASTEGATE UNIT FOR TURBOCHARGER

Technical Field

[1] The present invention relates to a turbocharger for increasing the output of an engine and, more particularly, to a wastegate unit for turbochargers, which su¬ percharges air or air/fuel mixture into an engine, using exhaust gas which is discharged to the outside. Background Art

[2] Generally, when more air/fuel mixture is forced into the cylinder of an engine, the engine produces a larger power under the same speed. Further, high pressure is generated and output is increased during an expansion stroke. In order to supercharge air/fuel mixture into the cylinder, a turbocharger is used.

[3] However, when boost pressure created in an intake manifold is excessively high, detonation and damage to the engine may result. Thus, in order to suppress excessive boost pressure, a wastegate unit is provided in the turbocharger.

[4] When the boost pressure reaches a predetermined value, some of exhaust gas is caused to bypass a turbine and flow to a wastegate by the wastegate unit. Thus, the exhaust gas is discharged to the outside without rotating the turbine.

[5] The operation of the engine, the turbocharger, and the wastegate unit will be described below with reference to FIGS. 1 to 4.

[6] FIG. 1 is a view schematically showing an engine to illustrate a conventional wastegate unit, FIG. 2 is a view showing a turbocharger equipped with the con¬ ventional wastegate unit, and FIGS. 3 and 4 are views illustrating the wastegate unit of the turbocharger shown in FIG. 2.

[7] While air/fuel mixture compressed in a cylinder 1 of the engine is ignited and expanded, an exhaust valve 2b is opened. A piston 3 moves up, so that burned gas is discharged. As such, the discharged exhaust gas passes through an exhaust gas inlet pipe 15 of a turbocharger 10, thus rotating a turbine 11.

[8] A fan 13a of a compressor 13 is synchronously rotated along with the turbine 11 which is rotated by the exhaust gas. At this time, external air is forcibly supplied into the cylinder 1, so that the output of the engine is increased. However, if all of the discharged exhaust gas is used to rotate the turbine 11, excessive boost pressure in proportion to the discharge amount of the exhaust gas is created in an intake manifold 5, thus causing detonation or the malfunction of the engine.

[9] In order to solve the problem, a wastegate unit 20 is provided. A wastegate 15a is formed on the exhaust gas inlet pipe 15 which is located upstream of the turbine 11. Further, the wastegate 15a is selectively closed by a wastegate valve 29.

[10] Thus, when excessive boost pressure is created in the intake manifold 5, the wastegate valve 29 is opened, so that some exhaust gas discharged from the cylinder 1 is not used to rotate the turbine 11, and is directly bypassed to the outside, thus preventing excessive boost pressure from being created.

[11] Such a conventional wastegate unit 20 includes an actuator 21, an actuator rod 23, a hinge bar 25, a coupling bar 27, and the wastegate valve 29.

[12] The actuator 21 is driven to selectively close the wastegate 15a. In a detailed de¬ scription, when the boost pressure exceeds a predetermined value, the actuator 21 opens the wastegate 15a so that some of the exhaust gas is bypassed. Further, when the boost pressure falls below a predetermined value, the actuator 21 closes the wastegate 15a, so that the exhaust gas is used to rotate the turbine 11.

[13] The actuator rod 23 is operated by the actuator 21. One end of the actuator rod 23 is connected to the actuator 21, and the other end of the actuator rod 23 is connected via a pin to a hinge bar 25, which will be described below.

[14] One end of the hinge bar 25 is connected via the pin to the actuator rod 23, while the other end of the hinge bar 25 is connected to the coupling bar 27 that will be described below. Thus, as the actuator 21 moves rectilinearly, the hinge bar 25 rotates about a pin joint 26.

[15] The coupling bar 27 is synchronously rotated along with the hinge bar 25 which is rotated by the actuator rod 23. One end of the coupling bar 27 is secured to the wastegate valve 29, using welding or a similar process. Thereby, the wastegate valve 29 is synchronously rotated along with the coupling bar 27.

[16] As such, the wastegate valve 29 is secured to the coupling bar 27, so that the wastegate valve 29 is synchronously rotated along with the coupling bar 27. Such a wastegate valve 29 rotates about the coupling bar 27, thus selectively closing the wastegate 15a. Since the wastegate valve 29 is rotated to close the wastegate 15a, the wastegate valve 29 is installed to be tilted relative to the coupling bar 27, as shown in FIGS. 3 and 4.

[17] As described above, when the boost pressure exceeds a predetermined value, the conventional wastegate unit 20 is operated as follows. That is, the actuator 21 is operated, so that the actuator rod 23 moves rectilinearly in the direction shown by arrow B in FIG. 2. In conjunction with the motion of the actuator rod 23, the hinge bar 25 rotates counterclockwise (as seen in the drawing).

[18] The coupling bar 27 rotates in a rotating direction of the hinge bar 25, that is, coun¬ terclockwise when shown from FIG. 4. At this time, the wastegate valve 29 secured to the coupling bar 27 opens the wastegate 15a. Thereby, some exhaust gas is bypassed through the wastegate 15a, thus regulating boost pressure. [19] Meanwhile, when boost pressure falls below a predetermined value, the actuator 21 moves the actuator rod 23 rectilinearly in the direction shown by arrow A in FIG. 2. The hinge bar 25 is rotated clockwise as seen in the drawing, in conjunction with the motion of the actuator rod 23. The coupling bar 27 rotates in the rotating direction of the hinge bar 25, that is, rotates clockwise as seen in FIG. 3. At this time, the wastegate valve 29 secured to the coupling bar 27 closes the wastegate 15a, so that the exhaust gas is not bypassed but is used to rotate the turbine 11 of the turbocharger 10.

[20] However, the conventional wastegate unit 20 constructed as described above is problematic in that it includes a plurality of components, such as the actuator 21, the actuator rod 23, the hinge bar 25, the coupling bar 27, and the wastegate valve 29, so that it is not easy to assemble, and the assembly process is complicated.

[21] Further, since the wastegate valve 29 rotates about a predetermined rotation axis to close the wastegate 15a, the wastegate valve 29 must be tilted. Thus, when the wastegate unit is used for a lengthy period of time, a tilting part 29a may be un¬ desirably cracked or damaged.

[22] The conventional wastegate unit 20 is problematic in that the wastegate valve 29, the hinge bar 25, and other components may be cracked or damaged, due to the pulsation of exhaust gas in the wastegate unit 20. Disclosure of Invention

Technical Problem

[23] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a wastegate unit that is easy to assemble and is capable of increasing the life-span of components.

[24] Another object of the present invention is to provide a wastegate unit that reduces the number of components, thus affording easy assembly. Technical Solution

[25] In order to accomplish the objects, the present invention provides a wastegate unit provided on a turbocharger of an engine, and including a wastegate valve to selectively close a wastegate, the wastegate being formed on an upstream side of a turbine of the engine turbocharger and discharging some exhaust gas so that the exhaust gas does not affect the turbine; a bushing to support the wastegate valve and guide linear motion of the wastegate valve; an actuator rod rectilinearly moving the wastegate valve; and an actuator to operate the actuator rod.

[26] According to an aspect of the invention, the actuator is a diaphragm unit driven by boost pressure created in an intake manifold.

[27] In another aspect of this embodiment, the actuator includes a sensor to sense boost pressure created in an intake manifold; and a solenoid valve to control the actuator, when it is determined that the boost pressure exceeds a predetermined value. [28] Preferably, an extrapolated line of a moving direction of the wastegate valve is parallel to a central axis passing through a center of the wastegate. [29] Further, a linear moving direction of the actuator rod is parallel to the central axis passing through the center of the wastegate. [30] Preferably, the actuator rod and the wastegate valve are detachably attached to each other.

Advantageous Effects

[31] As described above, the present invention enables a wastegate unit to be easily assembled, unlike the conventional wastegate unit having a plurality of components, thus shortening the time required for the assembly process. [32] Further, since a wastegate is opened or closed only by the linear movement of a wastegate valve, the life-span of components can be lengthened, in comparison with the conventional wastegate unit. [33] A wastegate unit may be applied to a conventional turbocharger without the necessity of changing the shape of the turbocharger. [34] When a wastegate valve is damaged due to the pulsation of exhaust gas in the wastegate unit, only the wastegate valve need be replaced with another one, without requiring replacement of the entire wastegate unit. Thus, maintenance costs are reduced. [35] Although the preferred embodiment of the present invention has been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Brief Description of the Drawings [36] FIG. 1 is a view schematically showing an engine to illustrate a conventional wastegate unit;

[37] FIG. 2 is a view schematically showing a turbocharger equipped with the con¬ ventional wastegate unit; [38] FIGS. 3 and 4 are views illustrating the operation of the conventional wastegate unit; [39] FIGS. 5 and 6 are views schematically showing a wastegate unit, according to the preferred embodiment of the present invention; and [40] FIG. 7 is an exploded perspective view of the wastegate unit shown in FIG. 5.

Best Mode for Carrying Out the Invention [41] The above and other objects, features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings. Those elements common to both the prior art and the preferred embodiment of the present invention will thus carry the same reference numerals.

[42] FIGS. 5 and 6 are views schematically showing a turbocharger equipped with a wastegate unit, according to the preferred embodiment of the present invention, and FIG. 7 is an exploded perspective view of the wastegate unit shown in FIG. 5.

[43] According to the preferred embodiment of the present invention, a wastegate unit

100 is installed in a turbocharger 10 of an engine, and regulates boost pressure created in an intake manifold 5 of the engine. The wastegate unit 100 includes an actuator 101, an actuator rod 103, a bushing 107, and a wastegate valve 105.

[44] The actuator 101 is driven to selectively close a wastegate 15a. When the boost pressure created in an intake manifold 5 of the engine exceeds a predetermined value, the wastegate 15a is opened to bypass some of the exhaust gas. Further, when the boost pressure falls below a predetermined value, the actuator 10 closes the wastegate 15a so that the exhaust gas is not bypassed but is used to rotate a turbine 11 of the tur¬ bocharger 10.

[45] The operation of the actuator 101 may be controlled by air or a computer. In the case where the actuator 101 is controlled by air, a diaphragm spring (not shown) is installed in the actuator 101. Thereby, when the boost pressure exceeds the elastic force of the spring, the diaphragm spring is elastically deformed, thus driving the actuator rod 103 and the wastegate valve 105 that will be described below in detail. Thereby, the wastegate 15a is opened, so that some of the exhaust gas is bypassed.

[46] Conversely, when the boost pressure does not exceed the elastic force of the spring, the actuator rod 103 and the wastegate valve 105 are returned to their original positions by the restoring force of the spring, thus closing the wastegate 15a. Thus, exhaust gas is not bypassed but flows only to the turbine 11 of the turbocharger 10.

[47] Meanwhile, in the case where the actuator 101 is controlled by the computer, a pressure sensor (not shown) is installed in the intake manifold 5. When the boost pressure exceeds a preset value, the pressure sensor sends a signal to the computer or an ECM. In response to the signal, a solenoid valve (not shown) which controls the actuator 101 is operated, thus driving the actuator rod 103 and the wastegate valve 105. Thereby, the wastegate 15a is opened, so that some of the exhaust gas is bypassed.

[48] Conversely, when the boost pressure falls below a preset value, the pressure sensor sends a signal to the computer or ECM. In response to the signal, the solenoid valve is operated, thus driving the actuator rod 103 and the wastegate valve 105. Thereby, the wastegate 15a is closed, so that the exhaust gas is not bypassed but flows only to the turbine 11 of the turbocharger 10. [49] The present invention may be applied to both of the actuators which are controlled by air or the computer, as described above. For ease of description of this invention, whether the actuator is controlled by air or the computer will not be considered.

[50] The actuator rod 103 is installed such that one end of the actuator rod 103 is connected to the actuator 101 to move longitudinally, and the other end of the actuator rod 103 is connected to the wastegate valve 105, which will be described below in detail. By the actuator 101, the actuator rod 103 rectilinearly moves in a lengthwise direction thereof. In conjunction with the rectilinear motion of the actuator rod 103, the wastegate valve 105 selectively closes the wastegate 15 a.

[51] The bushing 107 functions to support the actuator rod 103 and guide the lon¬ gitudinal linear motion thereof. The bushing 107 is secured to a turbocharger housing 10a, so that it also has a sealing function to prevent exhaust gas from being discharged to the outside when the wastegate 15a is closed.

[52] The wastegate valve 105 opens or closes the wastegate 15a using the actuator 101 and the linear motion of the actuator rod 103. According to the preferred embodiment of this invention, it is unnecessary to change existing intake and exhaust valves 2a and 2b (see, FIG. 1) of a cylinder 1 (see, FIG. 1) or to provide a different work line. Preferably, the existing intake and exhaust valves 2a and 2b may be adapted to this invention. In this case, the wastegate valve 105 is guided and supported by the bushing 107.

[53] As described above, in order to open or close the wastegate 15a using only the linear motion of the wastegate valve 105 without rotating the wastegate valve 105, it is preferable that an extrapolated line in the moving direction of the wastegate 105 be parallel to a central axis passing through the center of the wastegate 15a. This allows the wastegate valve 105 to be rectilinearly moved using a simple structure.

[54] Further, in order to use the existing turbocharger housing 10a without changing its shape, it is preferable that the linear moving direction of the actuator rod 103 be parallel to the central axis passing through the center of the wastegate 15a.

[55] Meanwhile, in order to install the wastegate unit 100 according to the preferred embodiment of the present invention without changing the shape of the existing tur¬ bocharger housing 10a, the actuator rod 103 has a 'U' shape. However, the actuator rod 103 may have a '-' shape. In this case, the actuator 101 may be placed opposite the position of the actuator which is shown in the drawing.

[56] Hereinafter, the operation of the wastegate unit 100 according to the preferred embodiment of the present invention will be described with reference to FIGS. 1, 5, and 6.

[57] After air/fuel mixture compressed in the cylinder 1 of the engine is ignited and expanded, the exhaust valve 2b is opened. A piston 3 moves up, so that burned gas is discharged though the exhaust valve. As such, the discharged exhaust gas passes through an exhaust gas inlet pipe 15 of the turbocharger 10, thus rotating the turbine 11. A fan 13a of a compressor 13 is synchronously rotated along with the rotating turbine 11. At this time, external air is forcibly supplied into the cylinder 1, so that the output of the engine is increased.

[58] As such, when air is supercharged into the cylinder by the turbocharger 10, and boost pressure created in the exhaust manifold 5 exceeds a predetermined value, the actuator 101 is operated, so that the actuator rod 103 horizontally moves in the direction of arrow C, as shown in FIG. 5, while being guided and supported by the bushing 107. In conjunction with the movement of the actuator rod 103, the wastegate valve 105 horizontally moves in the direction of arrow C. Thereby, the wastegate 15a is opened.

[59] Some of the exhaust gas is bypassed through the open wastegate 15a, so that the boost pressure created in the intake manifold 5 is lowered. Consequently, it is possible to adjust the amount of air forced into the cylinder 1 of the engine.

[60] Meanwhile, when the boost pressure created in the intake manifold 5 falls below a predetermined value, the actuator rod 103 horizontally moves in the direction of arrow C, as shown in FIG. 6. In conjunction with the movement of the actuator rod 103, the wastegate valve 105 horizontally moves in the direction of arrow D, so that the wastegate 15a is closed.

[61] At this time, exhaust gas is not bypassed due to the closed wastegate 15a but flows to the turbine 11 of the turbocharger 10, thus rotating the turbine 11. As the turbine 11 rotates, the fan 13a of the compressor 13 is synchronously rotated. Thereby, more external air is forced into the cylinder 1, thus enhancing the output of the engine.

[62] As such, by adjusting the amount of air or air/fuel mixture supplied to the cylinder

1 of the engine using the wastegate unit 100 of the turbocharger 10, the engine output can be stably maintained or increased.

[63] Further, even if excessive boost pressure is created in the intake manifold 5, the present invention reduces the boost pressure, thus minimizing detonation, and preventing overload of the engine. Industrial Applicability

[64] As described above, the present invention is applied to a turbocharger, thus increasing the output of an engine.

Claims

[1] A wastegate unit provided on a turbocharger of an engine, and comprising: a wastegate valve to selectively close a wastegate, the wastegate being formed on an upstream side of a turbine of the engine turbocharger and discharging some exhaust gas so that the exhaust gas does not affect the turbine; a bushing to support the wastegate valve and guide linear motion of the wastegate valve; an actuator rod connected to the wastegate valve, and rectilinearly moving the wastegate valve; and an actuator to operate the actuator rod. [2] The wastegate unit according to claim 1, wherein the actuator comprises: a diaphragm unit driven by boost pressure created in an intake manifold. [3] The wastegate unit according to claim 1, wherein the actuator comprises: a sensor to sense boost pressure created in an intake manifold; and a solenoid valve to control the actuator, when it is determined that the boost pressure exceeds a predetermined value. [4] The wastegate unit according to claim 1, wherein an extrapolated line of a moving direction of the wastegate valve is parallel to a central axis passing through a center of the wastegate. [5] The wastegate unit according to claim 4, wherein a linear moving direction of the actuator rod is parallel to the central axis passing through the center of the wastegate. [6] The wastegate unit according to claim 1, wherein the actuator rod and the wastegate valve are detachably attached to each other.