A high control accuracy quadratic surface turbocharging exhaust gas bypass check valve

Abstract

The application relates to the technical field of valves and discloses a high-control-precision parabolic surface turbocharging exhaust bypass check valve, which comprises a turbocharger turbine shell, a turbocharger compressor shell, a stepping motor, a parabolic surface check valve body and a motor action mechanism; an exhaust port is arranged on the turbocharger turbine shell, and the parabolic surface check valve body is arranged at the exhaust port; the stepping motor drives the valve body to rotate through the motor action mechanism to control the opening degree of the exhaust port; the windward surface of the valve body is a parabolic surface profile extension entity, and the motor action mechanism adopts a three-link structure. A gradually-changing gap is formed in the exhaust port by the parabolic surface entity with rotation, the effective flow area is limited from sharply increasing in the initial opening period, the opening degree and the exhaust flow rate present approximate linear mapping, and the accurate regulation of the exhaust bypass flow rate and the stable operation of the system are realized by combining the mechanical amplification constraint of the three-link mechanism on the input rotation angle of the motor.

Description

Technical Field

[0001] This invention relates to the field of valve technology, specifically to a high-precision quadratic surface turbocharger exhaust gas bypass check valve. Background Technology

[0002] A turbocharging system uses the exhaust gases from an internal combustion engine to drive a turbine, which in turn drives a coaxial compressor to compress the intake air, thus achieving a boost effect to improve engine output power and fuel economy. In a turbocharging system, the wastegate valve plays a crucial role in controlling boost pressure and protecting the turbine. Normally, when the engine is at low speed or the boost pressure is insufficient, the bypass valve remains closed, and all exhaust gases flow through the turbine to increase engine speed. When the system boost pressure reaches or exceeds a specified value, the bypass valve opens, and some exhaust gases bypass the turbine impeller and are directly discharged from the bypass channel to the exhaust pipe. This bypass diversion prevents excessively high intake pressure caused by over-boosting, avoiding engine malfunctions and maintaining stable system pressure.

[0003] Currently used turbocharger wastegate valves typically rely on airflow pressure to directly drive a linkage mechanism to control valve opening. This traditional mechanical control method is often limited by the stiffness of physical components such as springs, leading to low control accuracy and lag. Furthermore, most traditional wastegate valves employ a planar check valve structure. In the initial opening phase, even a small angle change in this simple planar valve can cause a sharp increase in the exhaust clearance, easily resulting in a non-linear surge in bypass exhaust flow and poor linear control performance. As engine requirements for response speed, control accuracy, and fuel economy continue to increase, existing wastegate valves urgently need improvement to meet the more linear and precise flow control needs of complex multi-stage turbocharging applications. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a high-precision quadratic surface turbocharger exhaust gas bypass check valve, which solves the problems of low control precision, nonlinear flow surge at the initial opening of planar valves, and easy position fluctuation and oscillation of valves under exhaust gas impact.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: a high-precision quadratic surface turbocharger exhaust gas bypass check valve, comprising: a turbocharger turbine housing, a turbocharger compressor housing, a stepper motor, a quadratic surface check valve body, and a motor actuation mechanism.

[0006] The turbocharger turbine housing has an exhaust port, and the turbocharger compressor housing is coaxially mounted with the turbine housing. A stepper motor is mounted on the turbocharger compressor housing, receiving control signals and outputting rotation angles. A quadratic surface check valve body is located at the exhaust port and connected to the turbocharger turbine housing via a valve body shaft. It rotates around the valve body shaft to block or open the exhaust port. A motor actuation mechanism is located between the stepper motor and the quadratic surface check valve body. The output shaft of the stepper motor is connected to the motor actuation mechanism, which is connected to the valve body shaft to drive the quadratic surface check valve body to rotate. The windward surface of the quadratic surface check valve body is a solid formed by the extension of a parabolic curved surface in three-dimensional space, and the quadratic surface check valve body has a valve limiting surface that abuts against the end face of the exhaust port.

[0007] In a preferred embodiment, the basic envelope shape of the parabolic surface profile further follows the parabolic spatial equation. The independent variables of the parabolic spatial equation are the lateral and longitudinal coordinate variables in a spatial rectangular coordinate system, the dependent variable is the corresponding vertical height coordinate variable, and the constant term includes the shape coefficient and the offset constant of the surface vertex along the vertical direction. The geometric center of the quadratic surface check valve body is the origin of the spatial rectangular coordinate system. The effective range of the lateral and longitudinal coordinate variables is determined according to the actual inner diameter of the exhaust port, and the boundary values ​​of the lateral and longitudinal coordinate variables are physically constrained by the radius of the exhaust port orifice. This convex parabolic solid extends into or out of the exhaust port with the rotation angle, forming a gradual gap between the inner wall of the exhaust port pipe and the surface of the quadratic surface check valve body, limiting the growth rate of the effective flow area within the small opening range, so that the flow area and the valve opening present an approximately linear mapping relationship.

[0008] In a preferred embodiment, the motor actuation mechanism includes a first link, a second link, and a third link. The input end of the first link is coaxially connected to the output shaft of the stepper motor; the output end of the third link is coaxially connected to the valve body rotation shaft of the quadratic surface check valve body; both ends of the second link are movably connected to the first and third links via hinged shafts, respectively. The length of the third link is greater than or equal to the length of the first link. This link length constraint converts the input angle of the stepper motor into a smaller output angle corresponding to the quadratic surface check valve body, thus amplifying the control indexing of the stepper motor at the mechanical transmission level.

[0009] In a preferred embodiment, the check valve further includes an electronic control unit and a sensor group, which includes an engine speed sensor, a throttle position sensor, and a boost pressure sensor. The engine speed sensor is located at a corresponding position on the engine crankshaft or camshaft, the throttle position sensor is located on the throttle body in the intake manifold, and the boost pressure sensor is located in the intake manifold downstream of the turbocharger compressor housing. The electronic control unit is electrically connected to the stepper motor and the sensor group, and the electronic control unit is used to output pulse width modulation signals to the stepper motor.

[0010] In a preferred embodiment, the electronic controller unit (ECU) pre-stores a target boost pressure pulse spectrum in its internal memory. The ECU is configured to receive engine speed data from an engine speed sensor and throttle opening data from a throttle position sensor, calculate the real-time target boost pressure setpoint from the target boost pressure pulse spectrum, and compare the actual boost pressure collected by the boost pressure sensor with the target boost pressure setpoint.

[0011] In one preferred embodiment, the electronic controller unit is configured to output a pulse width modulation (PWM) signal to the stepper motor when it determines that the actual boost pressure is lower than the target boost pressure setting. The stepper motor, based on the PWM signal, drives the quadratic surface check valve body to rotate via a motor actuation mechanism to reduce the opening of the exhaust port until the valve limiting surface of the quadratic surface check valve body abuts against the end face of the exhaust port to form a seal. Alternatively, the electronic controller unit is configured to output a PWM signal to the stepper motor when it determines that the actual boost pressure is greater than the target boost pressure setting. The stepper motor, based on the PWM signal, drives the quadratic surface check valve body to rotate via a motor actuation mechanism to increase the opening of the exhaust port, causing the valve limiting surface of the quadratic surface check valve body to separate from the end face of the exhaust port.

[0012] In a preferred embodiment, the electronic controller unit has a preset pressure tolerance band. The electronic controller unit is configured to output a control signal with a constant holding voltage to the stepper motor when the actual boost pressure falls within the preset pressure tolerance band. The stator coil inside the stepper motor is configured to receive the control signal and generate a static holding torque to lock the motor rotor, thus physically limiting the motor's operating mechanism. At this time, the stator coil locks the mechanical transmission chain to maintain the current opening angle position of the quadratic surface check valve body.

[0013] In a preferred embodiment, the electronic controller unit is configured to trigger a fault protection mechanism and stop outputting pulse width modulation signals when the signal from any sensor in the sensor group exceeds a reasonable physical threshold or a signal loss occurs, so that the stepper motor is maintained at the current safe opening position.

[0014] This invention provides a high-precision quadratic surface turbocharger exhaust gas bypass check valve. It offers the following advantages:

[0015] 1. This invention employs a quadratic curved surface check valve body structure with a parabolic profile on the windward side. In the initial stage of valve opening, the convex parabolic solid extends beyond the exhaust port with the rotation angle, forming a gradual gap between the inner wall of the pipe and the valve body surface, thus limiting the growth rate of the effective flow area. This structure overcomes the nonlinear defect of the rapid expansion of the flow area when a traditional planar valve opens, enabling the bypass exhaust gas flow rate and valve opening to exhibit an approximately linear mapping relationship within a certain angle range, thereby improving the stability and accuracy of exhaust gas diversion regulation.

[0016] 2. This invention employs a motor-driven mechanism comprising a first link, a second link, and a third link, with the length of the third link being greater than or equal to the length of the first link. During power transmission, this linkage mechanism converts the large input angle of the stepper motor into a smaller output angle of the quadratic surface check valve body. This mechanical dimensional constraint improves the mechanical control resolution of the valve rotation without altering the inherent indexing value of the motor, facilitating minute angle adjustments to the exhaust port opening.

[0017] 3. This invention employs an electronic controller unit combined with a pulse spectrum lookup table for closed-loop control of the stepper motor, and incorporates a pressure-to-tolerance locking mechanism. When the actual boost pressure falls within the tolerance range of the target value, the system outputs a constant holding voltage to the stepper motor, generating a static holding torque and physically limiting the mechanical transmission chain using electromagnetic properties. This design enables the valve body to resist the impact of high-pressure gas in the exhaust channel and remain stably hovered, avoiding mechanical oscillations in the actuator caused by system pressure fluctuations. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the linear control turbine exhaust bypass valve structure according to an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the turbine exhaust bypass valve profile according to an embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram showing the position of the bypass valve under different opening degrees according to an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram illustrating the working principle of the linear control turbine exhaust bypass valve according to an embodiment of the present invention.

[0022] Figure 5 This illustrates the relationship between the flow split ratio and valve angle of the bypass valve in an embodiment of the present invention.

[0023] Among them, 1. Secondary curved surface check valve body; 2. Turbocharger turbine housing; 21. Exhaust port; 3. Turbocharger compressor housing; 4. Stepper motor; 5. Motor actuation mechanism; 51. First connecting rod; 52. Second connecting rod; 53. Third connecting rod. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] See attached document Figure 1 and attached Figure 4 The present invention provides a high-precision quadratic surface turbocharger exhaust gas bypass check valve, comprising: a quadratic surface check valve body 1, a turbocharger turbine housing 2, a turbocharger compressor housing 3, a stepper motor 4, and a motor actuation mechanism 5.

[0026] The turbocharger turbine housing 2 has an exhaust port 21. The turbocharger compressor housing 3 is coaxially mounted with the turbocharger turbine housing 2. A stepper motor 4 is mounted on the turbocharger compressor housing 3 and is used to receive control electrical signals and output rotation angle.

[0027] A quadratic surface check valve body 1 is positioned at the exhaust port 21 and connected to the turbocharger turbine housing 2 via a valve body shaft. It rotates around the valve body shaft to block or open the exhaust port 21, controlling its opening degree. A motor actuation mechanism 5 is located between the stepper motor 4 and the quadratic surface check valve body 1. The stepper motor 4 actuates, driving the motor actuation mechanism 5, which in turn drives the quadratic surface check valve body 1 to rotate via the valve body shaft.

[0028] See attached document Figure 4 This invention provides a method for operating a high-precision quadratic surface turbocharger exhaust gas bypass check valve, comprising the following steps:

[0029] S10, the electronic controller unit collects engine speed, throttle opening and boost pressure parameters in real time;

[0030] S20, when the boost pressure is insufficient, the electronic controller unit outputs a pulse width modulation signal to the stepper motor 4, causing the stepper motor 4 to move. The stepper motor 4 drives the motor action mechanism 5 through the output shaft, which drives the quadratic surface check valve body 1 to rotate to reduce the opening of the exhaust port 21. During this process of reducing the opening, if the actual boost pressure still does not meet the target requirement, the drive continues until the valve limit surface of the quadratic surface check valve body 1 is completely abutted against the end face of the exhaust port 21 to form a seal. The exhaust gas flows in the turbine housing 2 of the turbocharger and does work on the turbine impeller.

[0031] S30, when the boost pressure is greater than the set value, the electronic controller unit outputs a pulse width modulation signal to the stepper motor 4, causing the stepper motor 4 to move. The stepper motor 4 drives the motor action mechanism 5 through the output shaft, which drives the quadratic surface check valve body 1 to rotate to increase the opening of the exhaust port 21. The valve limiting surface of the quadratic surface check valve body 1 gradually separates from the end face of the exhaust port 21, and the flow area of ​​the exhaust port 21 gradually increases. Some of the exhaust gas is directly discharged from the exhaust port 21 to the exhaust pipe.

[0032] S40, when the system boost pressure reaches the set value, the stepper motor 4 is locked, the motor action mechanism 5 is limited, so that the opening of the quadratic surface check valve body 1 remains stable, and the system boost pressure is stabilized near the set value.

[0033] In this embodiment, step S10 obtains the system status through electronic means, which can be specifically divided into the following sub-steps:

[0034] S110 utilizes a sensor array to acquire real-time operational physical quantity signals of the engine. Traditional turbocharger systems typically rely on the physical pressure of the intake airflow to directly trigger the bypass valve. This mechanical control method is often limited by physical conditions such as spring stiffness, easily leading to low control accuracy and lag in flow response. To achieve higher precision dynamic adjustment, this invention employs electronic control to replace the traditional mechanical structure. As a preferred approach, the sensor array includes an engine speed sensor, a throttle position sensor, and a boost pressure sensor.

[0035] The engine speed sensor is located at the corresponding position on the engine crankshaft or camshaft to detect the current engine speed signal; the throttle position sensor is located on the throttle body in the intake manifold to obtain the actual throttle opening signal reflecting the engine load demand; and the boost pressure sensor is located in the intake pipe downstream of the turbocharger compressor housing 3 to monitor the actual pressure value of the intake airflow sent into the engine combustion chamber after compression.

[0036] S120, the electronic control unit (ECU) receives and processes the physical quantity signals collected by the sensor array. The ECU establishes electrical signal communication connections with various sensors, parsing and converting the received signals into corresponding specific numerical parameters. In the specific control logic, the ECU identifies the current dynamic operating condition of the engine by comprehensively considering the load demand corresponding to the engine speed and throttle opening.

[0037] At this point, to obtain a precise control reference, the electronic control unit (ECU) retrieves a pre-calibrated target boost pressure pulse map from its internal memory. This pulse map is a data matrix obtained from engine bench tests, reflecting the optimal target boost pressure setpoint at different engine speeds and throttle openings. The ECU uses a two-dimensional interpolation algorithm to calculate the real-time target boost pressure setpoint from the pulse map based on the current engine speed and throttle opening, and then compares the real-time boost pressure values ​​with this setpoint.

[0038] By collecting and processing the above multidimensional parameters, the system can provide a data basis for the subsequent output of electronic signals to control the stepper motor 4 based on the load changes under the dynamic operating conditions of the engine, thereby alleviating the nonlinear response and hysteresis defects caused by mechanical control to a certain extent.

[0039] To ensure the integrity of the system's algorithm logic and avoid control dead zones, when the electronic controller unit detects that any sensor signal from the sensor group exceeds a reasonable physical threshold or a signal is lost, the system will trigger a fault protection mechanism, stopping the output of pulse width modulation signals and maintaining stepper motor 4 at its current safe opening position. The internal structures of various sensors and the basic data processing logic for signal conversion by the electronic controller unit can be conventionally configured according to the actual model by those skilled in the art; these are well-known technologies in the field and will not be elaborated upon here.

[0040] See attached document Figure 1 Appendix Figure 4 In this embodiment, regarding the physical response mechanism when the boost pressure is insufficient, step S20 is specifically divided into the following sub-steps:

[0041] S210, the electronic controller unit determines whether the system is in a state of insufficient boost pressure by calculating the difference between the current actual boost pressure and the target boost pressure setpoint. When the actual boost pressure is lower than the setpoint, the electronic controller unit processes the pressure difference data using its internally configured conventional proportional-integral-derivative control algorithm, calculates the target drive parameters, and outputs a pulse width modulation signal with a corresponding duty cycle to the stepper motor 4 mounted on the turbocharger compressor housing 3. The drive circuit inside the stepper motor 4 receives and analyzes the signal, generating a corresponding electromagnetic torque to drive the motor rotor to rotate by an angle corresponding to the duty cycle.

[0042] S220, in order to accurately transmit the rotational motion of the stepper motor 4 to the quadratic surface check valve body 1, the motor actuation mechanism 5 adopts a three-bar precision amplification mechanism. This three-bar precision amplification mechanism includes a first link 51, a second link 52, and a third link 53.

[0043] In terms of assembly structure, the input end of the first link 51 is coaxially connected to the output shaft of the stepper motor 4, the output end of the third link 53 is coaxially connected to the valve body rotating shaft of the quadratic surface check valve body 1, and the second link 52 serves as a floating arm, with its two ends being movably connected to the first link 51 and the third link 53 respectively through hinged rotating shafts.

[0044] When the stepper motor 4 drives the first link 51 to rotate, the first link 51 pulls the third link 53 to rotate via the second link 52. As a preferred embodiment, the system configures the length of the third link 53 to be equal to or greater than the length of the first link 51.

[0045] When the embodiment employs a geometric constraint where the length of the third link 53 is greater than the length of the first link 51, the stepper motor 4 rotates by a larger angle, and the output is converted into a smaller angle for the quadratic surface check valve body 1 to rotate. With the stepper motor 4's index value fixed, this mechanical transmission structure can amplify the control accuracy of the quadratic surface check valve body 1 to a certain extent.

[0046] S230, with the rotation of the third link 53, the quadratic surface check valve body 1 closes slightly around its own axis towards the exhaust port 21. As the stepper motor 4 continues to drive, the valve limiting surface on the quadratic surface check valve body 1 finally abuts against the end face of the exhaust port 21. This end face abutment action forms a physical seal on the mating surface, blocking the flow path of high-pressure gas inside the turbocharger to leak outward.

[0047] At this point, the exhaust gas produced by the engine cannot be discharged from the exhaust port 21 into the exhaust pipe; it is all confined to flow within the volute cavity of the turbocharger turbine housing 2. The exhaust gas concentrates its work on the turbine impeller, and the output shaft power drives the compressor to rotate through a coaxial structure, compressing the intake air entering the engine, thereby achieving an increase in boost pressure. The hydrodynamic conversion process of the airflow driving the impeller to do work inside the turbocharger can be understood by those skilled in the art based on conventional internal combustion engine intake and exhaust theories; it is well-known technology in the field and will not be elaborated further here.

[0048] See attached document Figure 2 Appendix Figure 3 and attached Figure 5 In this embodiment, regarding the pressure relief and precise diversion mechanism when the system pressurization pressure is too high, step S30 is specifically divided into the following sub-steps:

[0049] S310, when the electronic controller unit detects through the aforementioned acquisition and comparison logic that the actual boost pressure is greater than the target boost pressure setting value, the system needs to adjust the opening state of the bypass channel. The electronic controller unit processes the current pressure difference based on the built-in proportional-integral-derivative control algorithm and adjusts the duty cycle of the output pulse width modulation signal accordingly.

[0050] Upon receiving the updated electrical signal, the drive circuit inside the stepper motor 4 controls the motor rotor to rotate accordingly. The stepper motor 4 drives the valve body shaft of the quadratic surface check valve body 1 to rotate through the motor action mechanism 5, overcoming the internal pressure resistance and causing the quadratic surface check valve body 1 to gradually open at a corresponding angle away from the exhaust port 21.

[0051] S320, with the rotation of the quadratic surface check valve body 1, its valve limiting surface gradually separates from the end face of the exhaust port 21, and the physical flow area corresponding to the exhaust port 21 gradually increases. At this time, the high-pressure exhaust gas inside the turbine housing obtains an additional flow path. Some of the exhaust gas no longer enters the turbine volute cavity to drive the turbine impeller to do work, but directly overflows from the exhaust port 21 and is discharged into the downstream exhaust pipe. This bypass and diversion effect reduces the total effective gas energy acting on the turbine impeller, thereby reducing the compression intensity of the coaxial compressor on the intake air, which helps to suppress the continued rise of the system boost pressure.

[0052] S330, In conventional planar valve control systems, even a small change in angle during the initial valve opening can cause an exponential increase in the exhaust gap, leading to a nonlinear surge in bypass waste gas flow. To overcome this problem, this invention employs a quadratic surface valve body structure, with its windward face designed as a solid formed by the extension of a parabolic surface profile in three-dimensional space. The basic envelope shape of this quadratic surface solid follows the general parabolic spatial equation, and its general form is as follows:

[0053] ;

[0054] In the general formula of this space control equation, This refers to the horizontal coordinate variable in a spatial rectangular coordinate system; This refers to the vertical coordinate variable in a spatial rectangular coordinate system; For vertical height coordinates; The shape factor that determines the size and steepness of the surface opening; Let be the offset constant of the vertex of the curved surface along the vertical direction. By employing the aforementioned parabolic solid structure, the valve opening at a small angle exhibits an approximately linear mapping relationship between the opening size and the bypass exhaust gas flow rate. It should be noted that if this windward surface is replaced with another type of curved surface structure, such as a sphere, the system will lose the aforementioned specific linear regulation characteristics.

[0055] To achieve optimal control, as a preferred approach, the geometric center of the quadratic surface check valve body 1 is set as the origin of the spatial rectangular coordinate system. Based on the specific hydrodynamic characteristics of the exhaust channel, a specific optimized spatial control equation is given:

[0056] ;

[0057] In this spatial governing equation, , and All numerical units are in millimeters. To ensure that the above curved surface structure can be reliably machined and adapted to the exhaust channel, and The effective range of values ​​is determined based on the actual inner diameter of the exhaust port 21. Since the diameter of the exhaust bypass port of a conventional internal combustion engine is mostly in the range of 20 mm to 40 mm, and The boundary values ​​are physically constrained by the radius of the exhaust port 21 to ensure that the quadratic surface entity can be smoothly inserted into or removed from the exhaust channel. The equation defines a non-uniformly convex quadratic parabolic surface profile in a three-dimensional coordinate system, and clarifies the thickness distribution law of each point on the surface of the quadratic surface check valve body 1 relative to the reference plane.

[0058] S340, combined with appendix Figure 5 The control law shown alters the cross-sectional characteristics of fluid overflow based on the curved solid structure constructed from the aforementioned spatial control equations. When the quadratic surface check valve body 1 is in a smaller opening range, this quadratic surface solid structure extends into the exhaust port 21 or remains in the outlet region as the valve tilts. Constrained by the thickness of the convex curved surface, a restricted flow channel with a gradually changing gap is formed between the inner wall of the exhaust port 21 pipe and the surface of the quadratic surface solid. Compared with traditional planar cover-type check valves, this quadratic surface solid, which occupies the cross-sectional space of the flow channel, has a stronger physical constraint on the airflow when the valve is open, thus slowing down the increase in the effective flow area available for waste gas flow. Under this constraint, the slope of the bypass waste gas flow rate as the valve opening increases tends to be gentler.

[0059] The system utilizes the spatial compression effect of the physical surface to reduce the dramatic increase in cross-sectional area caused by valve rotation. This allows the flow area and valve opening to exhibit an approximately linear control relationship over a relatively wide range of rotation angles, effectively increasing the effective angle range of valve control and thus achieving stable regulation of the turbocharger's boost pressure. For the flow rate calculation and analysis of gas flowing through the variable cross-section orifice, those skilled in the art can perform calculations based on orifice outflow theory in fluid mechanics, which is well-known technology in the field and will not be elaborated upon here.

[0060] See attached document Figure 4 and attached Figure 5In this embodiment, the pressure stabilization and locking mechanism after the boosted pressure reaches the target requirement can be specifically divided into the following sub-steps:

[0061] S410, when the electronic controller unit confirms through comparative calculation that the current actual boost pressure has reached the target boost pressure setpoint, the system enters a pressure stabilization and maintenance state. Due to fluctuations in the fluid system and sensor signals, to avoid system oscillation caused by frequent actuator movements, the electronic controller unit is equipped with a preset pressure tolerance band. As a preferred approach, the specific range of this pressure tolerance band can be determined through bench calibration based on the measurement accuracy of the boost pressure sensor and the engine's steady-state control requirements, typically set to ±2% to ±5% of the target boost pressure setpoint.

[0062] When the actual boost pressure falls within this tolerance range, the pressure is considered to be within the acceptable range. At this point, the electronic controller unit stops changing the duty cycle of the pulse width modulation signal and instead outputs a control signal with a constant holding voltage to the stepper motor 4. Upon receiving this signal, the stator coil inside the stepper motor 4 utilizes its inherent electromagnetic characteristics to generate a static holding torque, thereby physically locking the motor rotor and stopping its original rotation.

[0063] S420, after the stepper motor 4 enters the locked state, the static holding torque it generates directly constrains the movement of the motor action mechanism 5. The first link 51, the second link 52, and the third link 53 in the transmission chain lose their relative motion capability because their input ends are fixed, and the entire three-bar precision amplification mechanism is physically limited. Relying on this rigid locking of the mechanical transmission chain, the quadratic surface check valve body 1 can resist the fluid impact force generated by the high-pressure exhaust gas flowing through the exhaust port 21 and stably hover at the corresponding opening angle position. Since the valve position no longer drifts, the physical flow area formed between the exhaust port 21 and the quadratic surface check valve body 1 remains constant.

[0064] S430, in this embodiment, the system sets the effective control angle range of the quadratic parabolic check valve body 1 between 0 and 40 degrees. Within this specific angle range, combined with the aforementioned quadratic parabolic solid structure defined by the spatial control equation, the numerical change in bypass exhaust gas flow rate and the valve rotation opening exhibit a relatively stable approximately linear mapping relationship. When the system is in the pressure stabilization and locking phase, the valve can remain suspended at any predetermined position within the 0 to 40 degree range, effectively matching the bypass exhaust gas flow rate that the engine must discharge under these conditions.

[0065] The position-holding mechanism achieved by electromagnetic locking, combined with the linearized flow characteristics brought about by the curved surface, helps to keep the total energy of the exhaust gas entering the turbine volute cavity to perform work in a stable state. Stable exhaust gas energy input helps to maintain the intake boost pressure output by the coaxial compressor without sudden changes, thereby ensuring that the engine intake system can continuously provide a stable boost effect that meets the target requirements.

[0066] To ensure the continued effectiveness of the algorithm, when changes in engine load demand or external physical interference cause the actual boost pressure to deviate from the preset pressure tolerance range, the electronic controller unit will release the stepper motor 4 from its locked state and re-trigger the aforementioned insufficient or excessive boost pressure adjustment process based on the current pressure difference, thus forming a continuous closed-loop control cycle. The electromagnetic fundamental principle of the stepper motor coil generating static holding torque can be understood and implemented by those skilled in the art based on conventional motor control theory; it is well-known in the field and will not be elaborated upon here.

Claims

1. A high-precision quadratic surface turbocharger exhaust gas bypass check valve, characterized in that, include: Turbocharger turbine housing (2), turbocharger compressor housing (3), stepper motor (4), quadratic surface check valve body (1), and motor actuation mechanism (5); The turbocharger turbine housing (2) has an exhaust port (21), and the turbocharger compressor housing (3) is coaxially arranged with the turbocharger turbine housing (2). The stepper motor (4) is mounted on the compressor housing (3) of the turbocharger, receives control electrical signals and outputs rotation angle; The quadratic surface check valve body (1) is located at the exhaust port (21) and is connected to the turbocharger turbine housing (2) via a valve body shaft. It rotates around the valve body shaft to block or open the exhaust port (21). The motor action mechanism (5) is located between the stepper motor (4) and the quadratic surface check valve body (1). The output shaft of the stepper motor (4) is connected to the motor action mechanism (5) for transmission. The motor action mechanism (5) is connected to the valve body rotating shaft to drive the quadratic surface check valve body (1) to rotate. The windward side of the quadratic surface check valve body (1) is a solid formed by the extension of a parabolic curved surface in three-dimensional space. The quadratic surface check valve body (1) has a valve limiting surface that abuts against the end face of the exhaust port (21).

2. The high-precision quadratic surface turbocharger exhaust gas bypass check valve according to claim 1, characterized in that, The motor actuation mechanism (5) includes a first link (51), a second link (52) and a third link (53); The input end of the first connecting rod (51) is coaxially connected to the output shaft of the stepper motor (4); The output end of the third link (53) is coaxially connected to the valve body shaft of the quadratic surface check valve body (1). The two ends of the second link (52) are movably connected to the first link (51) and the third link (53) respectively through hinged pivots; The length of the third link (53) is greater than or equal to the length of the first link (51).

3. The high-precision quadratic surface turbocharger exhaust gas bypass check valve according to claim 1, characterized in that, It also includes an electronic controller unit and a sensor group, the sensor group including an engine speed sensor, a throttle position sensor and a boost pressure sensor; The engine speed sensor is located at the corresponding position of the engine crankshaft or camshaft, the throttle position sensor is located on the throttle body of the intake manifold, and the boost pressure sensor is located in the intake pipe downstream of the turbocharger compressor housing (3). The electronic controller unit is electrically connected to the stepper motor (4) and the sensor group, and the electronic controller unit is used to output a pulse width modulation signal to the stepper motor (4).

4. The high-precision quadratic surface turbocharger exhaust gas bypass check valve according to claim 3, characterized in that, The target boost pressure pulse spectrum is pre-stored in the internal memory of the electronic controller unit; The electronic controller unit is configured to receive the engine speed collected by the engine speed sensor and the throttle opening collected by the throttle position sensor, calculate the real-time target boost pressure setpoint from the target boost pressure pulse spectrum, and compare the actual boost pressure collected by the boost pressure sensor with the target boost pressure setpoint.

5. A high-precision quadratic surface turbocharger exhaust gas bypass check valve according to claim 4, characterized in that, The electronic controller unit is configured to output the pulse width modulation signal to the stepper motor (4) when it is determined that the actual boost pressure is lower than the target boost pressure setting value; The stepper motor (4) drives the quadratic surface check valve body (1) to rotate through the motor action mechanism (5) according to the pulse width modulation signal to reduce the opening of the exhaust port (21) until the valve limiting surface of the quadratic surface check valve body (1) abuts against the end face of the exhaust port (21) to form a seal.

6. A high-precision quadratic surface turbocharger exhaust gas bypass check valve according to claim 4, characterized in that, The electronic controller unit is configured to output the pulse width modulation signal to the stepper motor (4) when it is determined that the actual boost pressure is greater than the target boost pressure setting value; The stepper motor (4) drives the quadratic surface check valve body (1) to rotate through the motor action mechanism (5) according to the pulse width modulation signal, so as to increase the opening of the exhaust port (21) and make the valve limiting surface of the quadratic surface check valve body (1) separate from the end face of the exhaust port (21).

7. A high-precision quadratic surface turbocharger exhaust gas bypass check valve according to claim 3, characterized in that, The electronic controller unit is configured to trigger a fault protection mechanism and stop outputting the pulse width modulation signal when it detects that the signal of any sensor in the sensor group exceeds a reasonable physical threshold or that a signal loss occurs, so that the stepper motor (4) is maintained at the current safe opening position.

8. A high-precision quadratic surface turbocharger exhaust gas bypass check valve according to claim 1, characterized in that, The basic envelope shape of the parabolic surface profile follows the parabolic space equation; The independent variables of the parabolic space equation are the horizontal and vertical coordinate variables in the spatial rectangular coordinate system, the dependent variable is the corresponding vertical height coordinate variable, and the constant term includes the shape coefficient and the offset constant of the surface vertex along the vertical direction.

9. A high-precision quadratic surface turbocharger exhaust gas bypass check valve according to claim 8, characterized in that, The geometric center of the quadratic surface check valve body (1) is the origin of the spatial rectangular coordinate system; The effective range of the horizontal coordinate variable and the vertical coordinate variable is determined according to the actual inner hole size of the exhaust port (21), and the boundary values ​​of the horizontal coordinate variable and the vertical coordinate variable are physically constrained by the diameter radius of the exhaust port (21).

10. A high-precision quadratic surface turbocharger exhaust gas bypass check valve according to claim 4, characterized in that, The electronic controller unit is equipped with a preset pressure tolerance band. The electronic controller unit is configured to output a control signal with a constant sustaining voltage to the stepper motor (4) when the actual boost pressure falls within the preset pressure tolerance range. The stator coil inside the stepper motor (4) is configured to receive the control electrical signal and generate a static holding torque to lock the motor rotor, thereby physically limiting the motor action mechanism (5).

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