Wastegate actuator arm for a turbocharger and turbocharger

Abstract

Turbochargers (10), comprising: a wastegate shaft (12) which is rotatable between a first position and a second position; an actuator (14) suitable for rotating the wastegate shaft (12) between the first position and the second position; and a wastegate actuator arm (20) arranged between the actuator (14) and the wastegate shaft (12) and connecting them together, wherein the wastegate actuator arm (20) comprises a first section (22) connected to the actuator (14), a second section (24) connected to the wastegate shaft (12), and a third section (26) arranged between the first section (22) and the second section (24) and connecting them together, and is designed to allow an angular deflection of the first section (22) relative to the second section (24); wherein the first section (22) of the wastegate actuator arm (20) is axially movable and the second section (24) of the wastegate actuator arm (20) is pivotable about an axis (32) of the wastegate shaft (12), wherein the first section (22) and the second section (24) are movable between a first position and a second position; wherein a longitudinal axis (28) of the first section (22) and a longitudinal axis (36) of the second section (24) define a first angle (38) when the wastegate actuator arm (20) is in the first position, and the longitudinal axis (28) of the first section (22) and the longitudinal axis (36) of the second section (24) define a second angle (44) when the wastegate actuator arm (20) is in the second position, the first angle (38) being greater than the second angle (44); wherein the second section (24) of the wastegate actuator arm (20) and the wastegate shaft (12) rotate uniformly about the axis (32) of the wastegate shaft (12); and wherein the first section (22) of the wastegate actuator arm (20) and the second section (24) of the wastegate actuator arm (20) are made of a rigid composite material and the third section (26) of the wastegate actuator arm (20) is made of a flexible polymer material.

Description

Technical field

[0001] The present disclosure relates to an actuator arm for a wastegate of a motor vehicle turbocharger. introduction

[0002] A wastegate is a device, either internal or external, attached to a vehicle's turbocharger, that prevents the turbocharger from generating more boost than desired. When the boost pressure exceeds a preset target value, the wastegate releases the excess pressure. A turbocharger wastegate is a small valve that opens when a certain threshold is reached, allowing excess exhaust gases to bypass the turbine and exit through the exhaust pipe once the preset boost pressure limit is reached.

[0003] Most engines can tolerate a small amount of additional boost pressure, and the temptation to continue is strong, as it's a relatively easy performance gain. However, there is only a certain amount of boost pressure a turbocharger can generate. A faulty or improperly installed wastegate can cause a variety of boost pressure problems.

[0004] In some turbochargers, the wastegate contains a spring on one side of a diaphragm and boost pressure on the other. At the point where the boost pressure exerts a greater force than the spring force, the wastegate opens to release the exhaust gases. Reducing the pressure the wastegate experiences or increasing the spring force causes the wastegate to open at higher boost pressures, allowing the engine to receive more charge and power. However, the limit lies in the turbocharger's capacity, both physically and in terms of airflow. If too much exhaust gas is forced through the turbine, the unit can overspeed, causing mechanical stress and potentially leading to problems such as broken shafts or compressor wheel failure.

[0005] Furthermore, the air flowing into the engine can become very unpredictable, a situation known as "surge." This can have a very detrimental effect on the engine's internal components and its power delivery. The solution is to tailor the turbocharger itself to the specific requirements and, if necessary, replace a standard version with one designed for this task. This could involve a physically larger turbocharger or a different turbine and compressor configuration.

[0006] Under normal operating conditions, every throttle body should produce a consistent boost pressure level. Stress caused by an aging or faulty turbocharger can overload the spring that opens the wastegate at a certain pressure. In this case, the wastegate flutters because the spring cannot keep it fully closed. The boost pressure oscillates, and the engine stutters and backfires as the boost pressure fluctuates rapidly. The engine may also respond sluggishly to throttle inputs, as the wastegate is likely venting air.

[0007] Because some of the turbocharger's power escapes through the fluttering wastegate, the turbocharger has to work harder to maintain the desired boost pressure, which generates heat, increases intake air temperatures and thus damages the engine.

[0008] In other turbochargers, the wastegate is actuated by an actuator that precisely controls its opening and closing. Typically, the wastegate is a valve that is opened and closed by rotating it. The wastegate valve is moved back and forth between the open and closed positions by an actuator. In many cases, an actuator arm connects the actuator to the wastegate and converts the axial or linear movement of the actuator into a rotary movement of the wastegate valve.

[0009] These types of connections typically use metallic components that slide against each other due to friction, such as at the interface between the lever pin and the connecting plate. These actuators can lead to noise and vibration problems because the components slide against each other and vibrate relative to one another. Furthermore, the sliding contact between these components causes wear and eventually leads to actuator arm failure. If these components are made of metallic materials, corrosion occurs, and the mass of the metallic components results in a lower natural frequency of the actuator arm, which in turn leads to increased noise and vibration problems.

[0010] DE 10 2010 004 559 A1 describes a connecting device for the articulated connection of a linearly driving drive element with a rotaryally driven actuating element of a charging device for an internal combustion engine, in particular of a motor vehicle. The connecting device comprises a pivot arm that can be rigidly connected to the actuating element for the transmission of torques about a pivot axis, a sliding element that can be rigidly connected to the drive element for the transmission of linear forces oriented at an angle to the pivot axis, and a bearing arrangement that movably couples the sliding element to the pivot arm such that the sliding element is displaceable relative to the pivot arm along a sliding axis parallel to the pivot axis and rotatable about the sliding axis and about a rotation axis perpendicular to the sliding axis.

[0011] DE 10 2014 204 849 A1 describes a method for manufacturing a mechanical device, in particular an exhaust gas turbocharger, with a control or regulating device and a mechanical transmission element, which is connected directly or indirectly to an actuator on the one hand and an actuating element on the other for transmitting a manipulated variable, wherein the transmission element is deformable before being connected to the actuator and the actuating element and is adapted to the other components of the device in its deformable state and fixed after adaptation by reducing its deformability, as well as a corresponding transmission element. The transmission element can be stiffened after assembly and adaptation.

[0012] While current wastegate actuator arms fulfill their purpose, the object of the invention is to provide a new and improved wastegate actuator arm that enables a reliable conversion of the linear motion of an actuator into a rotary motion of a wastegate valve and reduces the problems associated with conventional wastegate actuator arms in terms of noise, vibration, mass wear and reliability. Description

[0013] The invention is defined by the claims.

[0014] According to one aspect of the invention, a turbocharger wastegate actuator arm comprises a first section, a second section, and a third section connecting the first and second sections, the third section being configured to allow angular deflection of the first section relative to the second section. The first section of the wastegate actuator arm is axially movable, and the second section of the wastegate actuator arm is pivotable about an axis of the wastegate shaft, with the first and second sections being movable between a first position and a second position. A longitudinal axis of the first section and a longitudinal axis of the second section define a first angle when the wastegate actuator arm is in the first position. The longitudinal axis of the first section and the longitudinal axis of the second section define a second angle when the wastegate actuator arm is in the second position.The first angle is larger than the second angle. The second section of the wastegate actuator arm and the wastegate shaft rotate uniformly around the axis of the wastegate shaft. The first and second sections of the wastegate actuator arm are made of a rigid composite material, and the third section of the wastegate actuator arm is made of a flexible polymer material.

[0015] According to one embodiment, the second section of the wastegate actuator arm comprises a wedged opening which can engage with a corresponding projection of the wastegate shaft.

[0016] According to another embodiment, the second section of the wastegate actuator arm is designed so that it can be welded to the wastegate shaft.

[0017] According to a further embodiment, the second section of the wastegate actuator arm comprises a first part and a second part, wherein the first part of the second section of the actuator arm can be connected to the wastegate shaft, the second part of the second section of the actuator arm is connected to the third section of the actuator arm, and the first and second parts of the second section of the actuator arm are connected to each other.

[0018] According to another embodiment, the first part of the second section of the wastegate actuator arm is either screwed, pinned or riveted to the second part of the second section of the wastegate actuator arm.

[0019] According to another embodiment, the first section of the wastegate actuator arm is either screwed, pinned or riveted to the actuator.

[0020] According to a further aspect of the invention, a turbocharger comprises a wastegate shaft rotatable between a first position and a second position, an actuator suitable for rotating the wastegate between the first and second positions, and a wastegate actuator arm arranged between the actuator and the wastegate shaft and connecting them together, wherein the wastegate actuator arm comprises a first section connected to the actuator, a second section connected to the wastegate shaft, and a third section arranged between the first and second sections and connecting them together, and is suitable for enabling an angular deflection of the first section relative to the second section.The first section of the wastegate actuator arm is axially movable, and the second section is pivotable about an axis of the wastegate shaft, with both sections moving between a first position and a second position. A longitudinal axis of the first section and a longitudinal axis of the second section define a first angle when the wastegate actuator arm is in the first position. The longitudinal axis of the first section and the longitudinal axis of the second section define a second angle when the wastegate actuator arm is in the second position. The first angle is greater than the second angle. The second section of the wastegate actuator arm and the wastegate shaft rotate uniformly about the axis of the wastegate shaft.The first section of the wastegate actuator arm and the second section of the wastegate actuator arm are made of a rigid composite material, and the third section of the wastegate actuator arm is made of a flexible polymer material.

[0021] Further areas of application will become apparent from the present description. It should be understood that the description and specific examples serve only for illustration and are not intended to limit the scope of this disclosure. Brief description of the drawings

[0022] The figures described here serve only for illustration and are not intended to limit the scope of the present revelation in any way. Fig. Figure 1 is a perspective view of a turbocharger with a wastegate actuator arm according to an exemplary embodiment; Fig. Figure 2A is a perspective view of a wastegate actuator arm according to an exemplary embodiment, wherein the actuator arm is in a first position; Fig. 2B is a perspective view of the in Fig. 2A wastegate actuator arm shown, wherein the actuator arm is in a second position; Fig. 3 is a side view of the in Fig. 2A shown wastegate actuator arm; Fig. 4A is a top view of the in Fig. 2A actuator arm shown, wherein a distal end of the second section has a wedged opening according to an exemplary embodiment; Fig. 4B is a top view of the distal end of the second section of an actuator arm with a wedged opening according to another exemplary embodiment; Fig. Figure 5 is a top view of the distal end of the second section of an actuator arm, wherein the second section comprises a first part and a second part; and Fig. Figure 6 is a perspective view of the distal end of the second section of an actuator arm according to another exemplary embodiment. Detailed description

[0023] The following description is merely exemplary and is not intended to limit the present disclosure, application or use.

[0024] Referring to Fig. 1 comprises a turbocharger 10 for use with motor vehicle engines, including a wastegate shaft 12 that is rotatable between a first position and a second position. The wastegate shaft 12 is connected to an internal wastegate valve (not shown), with the wastegate shaft 12 and the wastegate valve rotating together. When the wastegate shaft 12 is in the first position, the wastegate valve is closed, and when the wastegate shaft 12 is in the second position, the wastegate valve is open.

[0025] An actuator 14 is designed to rotate the wastegate shaft 12 between the first and second positions. The actuator 14 includes a motor 16 that linearly moves an actuator rod 18 back and forth.

[0026] A wastegate actuator arm 20 is arranged between the actuator rod 18 of the actuator 14 and the wastegate shaft 12, connecting them. The wastegate actuator arm 20 comprises a first section 22, which is connected to the actuator rod 18, a second section 24, which is connected to the wastegate shaft 12, and a third section 26, which is arranged between the first and second sections 22 and 24, connecting them. The third section 26 is designed to allow angular deflection of the first section 22 relative to the second section 24.

[0027] In an exemplary embodiment, the first section 22 and the second section 24 of the actuator arm 20 are made of a rigid composite material, such as, but not limited to, a high-temperature carbon fiber material. The rigid composite material is designed such that the first section 22 can transmit linear motion from the actuator 14 with little or no deflection, and the second section 24 can transmit rotary motion to the wastegate shaft 12 with little or no deflection. The third section 26 of the actuator arm 20 consists of a flexible polymer material, such as high-temperature polyimide resins / composites like DMBZ-15 and PMR-15. The flexible polymer material is designed to allow angular deflection of the first section 22 relative to the second section 24.

[0028] Polyimides are a class of polymers distinguished by their resistance to chemicals, wear, radiation, and temperature. These properties have led to applications as diverse as engine casings for the aerospace industry and electronics packaging. The appeal of polyimides stems from their unique combination of high thermal stability, good chemical and solvent resistance, and excellent retention of mechanical properties at elevated temperatures. PMR-15 is a resin that is easily processed into composite materials, exhibits excellent mechanical properties for long-term use at temperatures up to 288 °C (550 °F), and is relatively inexpensive.DMBZ-15 enables the development of fiber-reinforced polymer matrix composites with operating temperatures up to 343 °C (650 °F), and DMBZ-15 graphite fiber-reinforced composites have an operating temperature range up to 335 °C (635 °F).

[0029] The first section 22 of the wastegate actuator arm 20 is axially movable back and forth along a longitudinal axis 28 of the first section 22 of the wastegate actuator arm 20 together with the actuator rod 18 of the actuator 14, as indicated by arrow 30. The second section 24 of the actuator arm 20 is pivotable about an axis 32 of the wastegate shaft 12 together with the wastegate shaft 12, as indicated by arrow 34. The first and second sections 22, 24 of the actuator arm 20 together with the actuating rod 18 and the wastegate shaft 12 are movable between the first position and the second position.

[0030] In Fig. Figure 2A shows the wastegate actuator arm 20 in its first position, away from the turbocharger 10. The longitudinal axis 28 of the first section 22 and a longitudinal axis 36 of the second section 24 form a first angle 38 when the actuator rod 18, the wastegate actuator arm 20, and the wastegate shaft 12 are in their first position. The actuator 14 moves the first section 22 from the first position to the second position, as indicated by arrow 40, which in turn rotates the second section 24 from the first position to the second position, as indicated by arrow 42.

[0031] In Fig. Figure 2B shows the wastegate actuator arm 20 in its second position, away from the turbocharger 10. The longitudinal axis 28 of the first section 22 and the longitudinal axis 36 of the second section 24 form a second angle 44 when the actuator rod 18, the wastegate actuator arm 20, and the wastegate shaft 12 are in their second position. The first angle 38 is larger than the second angle 44 when the rotational position of the second section 24 changes relative to the first section 22.

[0032] Referring to Fig. Section 3 includes a distal end 46 of the first section 22 with an opening 48 suitable for attaching the first section 22 to the actuator rod 18, for example, as a non-limiting example, with a threaded fastener 50. It is understood that other methods may also be used to connect the distal end 46 of the first section 22 to the actuator rod 18, such as, but not limited to, pin or rivet connections.

[0033] A distal end 52 of the second section 24 can be rigidly connected to the wastegate shaft 12, whereby the second section 24 of the wastegate actuator arm 20 and the wastegate shaft 12 rotate uniformly about the axis 32 of the wastegate shaft 12. A wedge engagement between the distal end 52 of the second section 24 and the wastegate shaft 12 ensures uniform rotation of the second section 24 and the wastegate shaft 12. The second section 24 has a cast-in or machined opening 54 in the distal end 52, which can engage with a cast-in or machined projection 56 of the wastegate shaft 12. Referring to Fig. In an exemplary embodiment, the distal end 52 of the second section 24 of section 4A contains a star-shaped opening 54A which can engage with a corresponding star-shaped projection of the wastegate shaft 12. Referring to Fig. In another exemplary embodiment, the distal end 52 of the second section 24 contains a slot 54B adapted to engage a correspondingly shaped projection 56A of the wastegate shaft 12. In another exemplary embodiment, there is an interference fit between the wedge opening 54 formed in the distal end 52 of the second section 24 and the projection 56 of the wastegate shaft 12, with the distal end 52 of the second section 24 being pressed onto the projection 56 of the wastegate shaft 12. In yet another exemplary embodiment, the distal end 52 of the second section 24 is welded to the wastegate shaft 12.

[0034] In another exemplary embodiment (see Fig. 5) The second section 24 of the wastegate actuator arm 20 comprises a first part 58 and a second part 60. The first part 58 of the second section 24 of the wastegate actuator arm 20 is connected to the wastegate shaft 12. The second part 60 of the second section 24 of the wastegate actuator arm 20 is connected to the third section 26 of the wastegate actuator arm 20. The first part 58 and the second part 60 of the second section 24 of the wastegate actuator arm 20 are connected to each other. As shown, the first part 58 and the second part 60 of the second section 24 of the wastegate actuator arm 20 are connected by a threaded fastening element 62. It goes without saying that the first part 58 and the second part 60 of the second section 24 can also be joined by other methods, such as by a pin or rivet connection, without being limited to that.

[0035] Referring to Fig.In another exemplary embodiment, the distal end 52 of the second section 24 of the wastegate actuator arm 20 forms a substantially U-shaped slot 64, which is suitable for engaging in a corresponding flat projection 56B of the wastegate shaft 12. The flat projection 56B of the wastegate shaft 12 can be machined into the wastegate shaft 12 or cast in during the manufacture of the wastegate shaft 12.

[0036] A wastegate actuator arm for a turbocharger according to the present disclosure offers several advantages. These include the elimination of corrosion problems that occur with conventional actuator arms with metallic components, the reduction of frictional wear between components that have a sliding frictional engagement, the reduction of mass and the improvement of modal / dynamic load performance due to the composition of the composite material, as well as the reduction or elimination of noise and vibration problems associated with multi-composite metallic actuator arms.

Claims

[1] Turbocharger (10), comprising: a wastegate shaft (12) rotatable between a first position and a second position; an actuator (14) adapted to rotate the wastegate shaft (12) between the first position and the second position; and a wastegate actuator arm (20) arranged between the actuator (14) and the wastegate shaft (12) and connecting them to one another, the wastegate actuator arm (20) comprising a first section (22) connected to the actuator (14), a second section (24) connected to the wastegate shaft (12), and a third section (26) arranged between the first section (22) and the second section (24) and connecting them to one another, and being designed to enable angular deflection of the first section (22) relative to the second section (24); wherein the first portion (22) of the wastegate actuator arm (20) is axially movable and the second portion (24) of the wastegate actuator arm (20) is pivotable about an axis (32) of the wastegate shaft (12), the first portion (22) and the second portion (24) being movable between a first position and a second position; wherein a longitudinal axis (28) of the first section (22) and a longitudinal axis (36) of the second section (24) define a first angle (38) when the wastegate actuator arm (20) is in the first position, and the longitudinal axis (28) of the first section (22) and the longitudinal axis (36) of the second section (24) define a second angle (44) when the wastegate actuator arm (20) is in the second position, the first angle (38) being greater than the second angle (44); wherein the second portion (24) of the wastegate actuator arm (20) and the wastegate shaft (12) rotate uniformly about the axis (32) of the wastegate shaft (12); and wherein the first portion (22) of the wastegate actuator arm (20) and the second portion (24) of the wastegate actuator arm (20) are made of a rigid composite material and the third portion (26) of the wastegate actuator arm (20) is made of a flexible polymer material. [2] Turbocharger (10) according to claim 1, wherein the second portion (24) of the wastegate actuator arm (20) comprises a first part (58) and a second part (60), wherein the first part (58) of the second portion (24) of the wastegate actuator arm (20) is connected to the wastegate shaft (12), the second part (60) of the second portion (24) of the wastegate actuator arm (20) is connected to the third portion (26) of the wastegate actuator arm (20), and the first part (58) and the second part (60) of the second portion (24) of the wastegate actuator arm (20) are connected to each other. [3] Turbocharger (10) according to claim 2, wherein the first part (58) of the second section (24) of the wastegate actuator arm (20) is either bolted, pinned or riveted to the second part (60) of the second section (24) of the wastegate actuator arm (20). [4] Turbocharger (10) according to claim 1, wherein the first portion (22) of the wastegate actuator arm (20) is either bolted, pinned or riveted to the actuator (14). [5] Wastegate actuator arm (20) for a turbocharger (10), the wastegate actuator arm (20) comprising: a first section (22); a second section (24); and a third section (26) located between and connecting the first section (22) and the second section (24) and allowing angular deflection of the first section (22) relative to the second section (24); wherein the first portion (22) of the wastegate actuator arm (20) is axially movable and the second portion (24) of the wastegate actuator arm (20) is pivotable about an axis (32) of a wastegate shaft (12), the first portion (22) and the second portion (24) being movable between a first position and a second position; wherein a longitudinal axis (28) of the first section (22) and a longitudinal axis (36) of the second section (24) define a first angle (38) when the wastegate actuator arm (20) is in the first position, and the longitudinal axis (28) of the first section (22) and the longitudinal axis (36) of the second section (24) define a second angle (44) when the wastegate actuator arm (20) is in the second position, the first angle (38) being greater than the second angle (44); wherein the second portion (24) of the wastegate actuator arm (20) and the wastegate shaft (12) rotate uniformly about the axis (32) of the wastegate shaft (12); and wherein the first portion (22) of the wastegate actuator arm (20) and the second portion (24) of the wastegate actuator arm (20) are made of a rigid composite material and the third portion (26) of the wastegate actuator arm (20) is made of a flexible polymer material.

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