EGR valve angle position control mechanism

Abstract

The utility model discloses an EGR valve angle position control mechanism which comprises a valve body, a valve plug, a servo motor and a gear transmission mechanism. The servo motor drives the reduction gear set to drive the valve shaft to rotate, and the valve plug rotates along with the valve shaft to adjust the opening degree of the valve port. The valve body is integrated with an angle position sensor, a valve plug position signal is fed back to an ECU in real time, and the opening degree is accurately controlled by combining engine working condition data. The problems that a traditional EGR valve is low in electromagnetic driving precision, slow in response and free of feedback are solved, and the EGR valve has the advantages of being accurate in control, fast in response and high in stability and is suitable for the field of emission reduction and energy conservation of automobile engines.

Description

Technical Field

[0001] This utility model relates to the technical field of engine exhaust gas recirculation (EGR) systems, specifically to an EGR valve angle position control mechanism. Background Technology

[0002] The EGR valve is an electromechanical product installed on a diesel engine to control the amount of exhaust gas recirculated back to the intake system. It is typically located on the right side of the intake manifold, near the throttle body, and connected to a short metal pipe leading to the exhaust manifold. Its function is to control the amount of exhaust gas entering the intake manifold, allowing a certain amount of exhaust gas to flow into the intake manifold for recirculation. The EGR valve is a very important and critical component of the exhaust gas recirculation system.

[0003] Traditional EGR valves control the valve opening by directly driving the valve stem to extend or retract using electromagnetic force, which has the following drawbacks:

[0004] 1. Low control precision: It is difficult to accurately adjust the valve opening;

[0005] 2. Response delay: Electromagnetic drives are susceptible to interference and have slow dynamic response;

[0006] 3. Lack of feedback: No position sensor, unable to monitor valve plug position in real time;

[0007] 4. Poor stability: It can easily lead to increased engine fuel consumption and unstable operation. Utility Model Content

[0008] To address the shortcomings of existing technologies, the purpose of this invention is to provide a high-precision, fast-response EGR valve with position feedback. It uses a servo motor to drive a gear set and combines an angle sensor to adjust the valve plug rotation angle in real time, thereby precisely controlling the valve opening and improving engine combustion efficiency.

[0009] To achieve the above objectives, this utility model provides the following technical solution: an EGR valve angle position control mechanism, comprising:

[0010] The valve body has a valve port and a valve shaft, and a valve plug located at the valve port is installed at the end of the valve shaft.

[0011] The drive control device includes a servo motor, a drive gear, a reduction gear, and a transmission gear. The transmission gear is mounted on the bottom of the valve shaft, the drive gear is mounted on the output shaft of the servo motor, and the reduction gear includes a large gear and a small gear that are fixed to each other. The small gear meshes with the transmission gear, and the large gear meshes with the drive gear.

[0012] An angle position sensor, located below the transmission gear, is used to detect the rotation angle of the valve shaft;

[0013] A reset torsion spring is located between the valve shaft and the valve body;

[0014] The circuit board is located inside the valve body and connected to the vehicle ECU; the angle position sensor is electrically connected to the circuit board.

[0015] The vehicle's ECU controls a servo motor to drive the valve shaft to rotate via a circuit board, based on engine operating condition signals and feedback signals from the angle and position sensors, thereby adjusting the opening degree of the valve plug relative to the valve port.

[0016] The large gear and small gear of the reduction gear are integrated into one piece.

[0017] The reset torsion spring is sleeved on the outer wall of the valve shaft, with one end abutting against the valve body and the other end abutting against the boss of the valve shaft.

[0018] The angle position sensor is a non-contact magnetic induction sensor.

[0019] The beneficial effects of this utility model are:

[0020] 1. Precise control: Servo motor + gear set transmission enables continuous adjustment of valve opening;

[0021] 2. Fast response: Eliminates electromagnetic interference and shortens response time;

[0022] 3. Real-time feedback: Closed-loop adjustment using angle sensor improves control accuracy;

[0023] 4. Stable and reliable: The reset torsion spring ensures reset after power failure, reducing fuel consumption and emissions.

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0025] Figure 1 This is a perspective view of a specific embodiment of the present utility model;

[0026] Figure 2 This is a cross-sectional view of a specific embodiment of the present utility model;

[0027] Figure 3 This is a perspective view of the internal structure of a specific embodiment of the present invention.

[0028] Explanation of reference numerals in the attached diagram: 1-Valve body; 2-Valve port; 3-Valve shaft; 4-Valve plug; 5-Servo motor; 6-Drive gear; 7-Reduction gear; 71-Large gear; 72-Small gear; 8-Transmission gear; 9-Angle position sensor; 10-Reset torsion spring; 11-Circuit board. Detailed Implementation

[0029] The present invention will be described in detail below through embodiments, which are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention.

[0030] like Figure 1 — Figure 3 As shown, this embodiment provides an EGR valve angle position control mechanism. Its core uses a servo motor to precisely drive the valve plug to rotate and adjust the valve opening, and integrates position feedback to achieve closed-loop control. The specific structure and connection relationships are as follows:

[0031] I. Overall Structural Composition

[0032] The EGR valve is installed on the recirculation line between the engine exhaust manifold and the intake manifold to control the amount of exhaust gas recirculation. Its main body consists of five parts: the valve body, valve plug assembly, drive control device, feedback and reset assembly, and control circuit. These parts work together to achieve high-precision opening adjustment.

[0033] II. Detailed Structure and Connection Relationships of Each Component

[0034] (a) Valve body

[0035] The valve body 1 is made of aluminum alloy casting (or high-temperature resistant stainless steel), with a hollow interior forming a gas flow channel. One side has an exhaust gas inlet connected to the engine exhaust manifold, and the other side has an exhaust gas outlet connected to the intake manifold. The exhaust gas inlet and outlet are connected by an annular valve port 2 (i.e., valve port 2 is an annular opening surrounding the valve shaft 3). A motor mounting bracket (for mounting a servo motor 5) is bolted to one side of the valve body 1. An internal sensor mounting slot (for fixing an angle position sensor 9) is provided. A cooling channel is also provided on the valve body for cooling liquid to pass through.

[0036] (ii) Valve plug assembly

[0037] The valve plug 4 is a disc-shaped structure made of high-temperature resistant alloy steel (such as 4Cr10Si2Mo), with a diameter slightly larger than the inner diameter of the valve port 2 (e.g., the inner diameter of the valve port 2 is 50mm, and the diameter of the valve plug 4 is 52mm). This ensures that the opening degree can be controlled by the fit between the edge and the valve port 2 during rotation. One end of the valve shaft 3 (the valve shaft 3 is a solid stainless steel shaft with a diameter of 8mm) is fixed to the center of the valve plug 4 by an interference fit. The other end of the valve shaft 3 passes through the sealed bearing at the top of the valve body 1 (to prevent exhaust gas leakage) and extends to the drive control device. The edge of the valve plug 4 has an annular sealing surface, which can achieve an airtight seal when in contact with the valve port 2 (leakage ≤0.5% when the opening degree is 0%).

[0038] (iii) Drive control device

[0039] The core of the drive control device is to transmit the rotational motion of the servo motor to the valve shaft 3 after reduction and torque amplification through a gear set, specifically including:

[0040] Servo motor 5: A high-response DC brushless servo motor (rated voltage 12V, torque 0.5N·m, speed adjustable from 0-3000rpm) is fixed to the motor mounting base of valve body 1 by bolts, and its output shaft extends vertically downward.

[0041] Drive gear 6: a small module gear (module 0.5, number of teeth 15), which is fixedly connected to the output shaft of servo motor 5 via a flat key (to ensure synchronous rotation), and is used to receive the initial driving force of the motor.

[0042] Reduction gear 7: Employs a two-stage reduction structure, comprising a large gear 71 and a small gear 72 (integrated injection molded on the same gear shaft, made of POM plastic with glass fiber reinforcement to reduce noise and weight). The small gear 72 is coaxially fixed to the large gear 71 (gear ratio 1:3, i.e., small gear 72 has 10 teeth, large gear 71 has 30 teeth). The small gear 72 meshes with the transmission gear 8, and the large gear 71 meshes with the drive gear 6 (drive gear 6 has 15 teeth, large gear 71 has 30 teeth, forming a 1:2 reduction ratio). The overall reduction ratio is 1:6 (servo motor 5 output shaft rotates 6 times per revolution, valve shaft 3 rotates 1 time per revolution).

[0043] Transmission gear 8: It is a spur gear (module 0.8, number of teeth 30), which is fixed to the middle of valve shaft 3 (near valve plug 4) through the center hole interference fit. When it rotates, it directly drives valve shaft 3 to rotate synchronously.

[0044] (iv) Feedback and reset components

[0045] Angle position sensor 9: A non-contact magnetic induction sensor (such as a Hall effect sensor) is installed in the sensor mounting slot at the bottom of the valve body 1, directly opposite the magnet below the transmission gear 8 (the magnet is embedded in the spokes of the transmission gear 8, and the magnetic field angle changes as the gear rotates). The sensor detects the rotation angle of the transmission gear 8 (i.e., valve shaft 3) in real time (accuracy ±0.1°) and converts the analog signal into a digital signal before transmitting it to the circuit board 11.

[0046] The reset torsion spring 10 is a stainless steel helical spring fitted onto the outer wall of the valve shaft 3 (located between the sealing bearing at the top of the valve body 1 and the transmission gear 8). One end of the spring is fixed to the positioning groove on the inner wall of the valve body 1 by a hook, and the other end is engaged with the boss of the valve shaft 3. When the servo motor 5 is de-energized, the elastic force of the reset torsion spring 10 drives the valve shaft 3 to rotate in the opposite direction to the preset zero position (the valve plug 4 completely closes the valve port 2, with an opening of 0%).

[0047] (v) Control circuit

[0048] The valve body 1 integrates a printed circuit board 11 (PCB), which is connected to the vehicle's ECU (Electronic Control Unit) via a wiring harness and receives feedback signals from the angle position sensor 9. The PCB integrates a microcontroller (such as an STM32 microcontroller), a motor drive module (such as an H-bridge driver chip), and a power conversion module (converting the vehicle's 12V voltage to 5V for the sensor and MCU). The ECU calculates the required EGR rate based on the engine's real-time operating conditions (such as engine speed, load, and intake air temperature) and sends the target opening command to the PCB via the CAN bus. The PCB, combined with the current angle signal from the angle position sensor 9, calculates the target rotation angle of the servo motor 5, drives the motor output shaft to rotate, and transmits the rotation to the valve shaft 3 via a gear set, ultimately adjusting the rotation angle of the valve plug 4 (for example, when the target opening is 30%, the contact gap between the edge of the valve plug 4 and the valve port 2 is 30% of the circumference).

[0049] III. Working Process (Taking different engine operating conditions as examples)

[0050] Scenario 1: Engine under low load (requiring low-flow EGR)

[0051] When the engine is idling or under low speed and light load, the ECU calculates a target EGR rate of 10% based on the intake air volume requirement (corresponding to a valve opening angle of approximately 15°). At this time, the ECU sends a "15° opening" command to the PCB board via the CAN bus; the PCB board reads the current signal from the angle position sensor 9 (assuming the valve shaft 3 is currently at zero position, with an angle of 0°), and calculates the required forward rotation of the servo motor 5 (after conversion using the gear set, the servo motor 5 needs to rotate 0.25 revolutions (15° / 6)). The motor output shaft drives the drive gear 6 to rotate, and after two-stage reduction by the reduction gears 7 (large gear 71 and small gear 72), the transmission gear 8 rotates 15° at low speed and high torque, thereby driving the valve shaft 3 and valve plug 4 to rotate 15°. The edge of the valve plug 4 separates from the valve port 2, forming an exhaust gas passage with an area of ​​approximately 10%, achieving a small-flow EGR.

[0052] Scenario 2: Engine under high load conditions (requiring high-flow EGR)

[0053] When the engine is under high speed and high load (e.g., 3000 rpm, 80% load), the ECU calculates a target EGR rate of 30% (corresponding to a valve opening of approximately 50° rotation angle). The PCB reads the current angle (assumed to be 15°) and calculates that it needs to rotate another 35° (total target 50°). The servo motor 5 accelerates its rotation (after conversion via gear set, the motor rotates approximately 0.58 revolutions (35° / 6)). After transmission via gear set, the valve shaft 3 and valve plug 4 rotate 35°, increasing the contact gap between the edge of valve plug 4 and valve port 2 to 50% of the circumference, significantly increasing the exhaust gas flow area and meeting the exhaust gas recirculation requirements under high load.

[0054] Scenario 3: Power outage or fault state

[0055] When the vehicle loses power or the servo motor 5 fails, the spring force of the reset torsion spring 10 (the preload is designed to be ≥5 N·m) drives the valve shaft 3 to rotate in the opposite direction until the valve plug 4 completely closes the valve port 2 (the angle position sensor 9 provides a 0° signal), ensuring that exhaust gas will not enter the intake system due to misoperation and ensuring the safe operation of the engine.

[0056] IV. Verification of Key Parameters

[0057] Control accuracy: The minimum step angle of servo motor 5 is 0.01° (through PWM modulation subdivision). After the gear set reduces the speed by 6 times, the minimum adjustment angle of valve plug 4 is 0.00167° (in actual applications, it can be stably controlled to ±0.1°, corresponding to an opening accuracy of ±0.3%).

[0058] Response time: The time from when the ECU issues a command to when valve plug 4 begins to act is ≤10ms (50-100ms for traditional solenoid valves), and the time to reach the target opening degree is ≤50ms (200-300ms for traditional solenoid valves).

[0059] Reliability: The sealing surface hardness of valve plug 4 and valve port 2 is ≥HRC55 (resistant to high temperature wear), and the fatigue life of return torsion spring 10 is ≥100,000 cycles (meeting the requirements of the entire vehicle life cycle).

[0060] In summary, this embodiment solves the problems of low control accuracy, slow response, and susceptibility to interference of traditional EGR valves by using precise transmission of servo motor + gear reduction group, real-time feedback of angle position sensor and safety protection of reset torsion spring. It is suitable for EGR systems of engines with emission standards of China VI and above, and can effectively reduce nitrogen oxide (NOx) emissions and optimize fuel economy.

Claims

1. An EGR valve angular position control mechanism characterized by comprising: The utility model relates to a valve drive control device, which comprises a valve body (1) provided with a valve port (2) and a valve shaft (3) having a valve plug (4) installed at the end of the valve shaft (3) and located at the valve port (2), a drive control device, a servo motor (5), a drive gear (6), a reduction gear (7) and a transmission gear (8), wherein the transmission gear (8) is installed at the bottom of the valve shaft (3), the drive gear (6) is installed on the output shaft of the servo motor (5), the reduction gear (7) comprises a large gear (71) and a small gear (72) fixed with each other, the small gear (72) is engaged with the transmission gear (8), and the large gear (71) is engaged with the drive gear (6), an angle position sensor (9) arranged below the transmission gear (8) for detecting the rotation angle of the valve shaft (3), a reset torsion spring (10) arranged between the valve shaft (3) and the valve body (1), a circuit board (11) arranged in the valve body (1) and connected with the automobile ECU, and the angle position sensor (9) is electrically connected with the circuit board (11). The automobile ECU controls the servo motor (5) to drive the valve shaft (3) to rotate through the circuit board (11) according to the engine working condition signal and the feedback signal of the angle position sensor (9), so as to adjust the opening degree of the valve plug (4) to the valve port (2). The large gear (71) and the small gear (72) of the reduction gear (7) are of an integrated structure. The reset torsion spring (10) is sleeved on the outer wall of the valve shaft (3), one end of which abuts against the valve body (1) and the other end of which abuts against the boss of the valve shaft (3). The angle position sensor (9) is a non-contact magnetic induction sensor. ​ ​ 2. The EGR valve angular position control mechanism according to claim 1, characterized by ​ 3. The EGR valve angular position control mechanism according to claim 1, characterized by ​ 4. The EGR valve angular position control mechanism according to claim 1, characterized by ​

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