An EGR exhaust gas recirculation slow closing valve system and method

Abstract

The present invention discloses an EGR exhaust gas recirculation slow-closing valve system and method. By collecting the real-time EGR valve stem position and inputting it into an ECU controller, the ECU controller can control the EGR valve stem at different positions using different rates according to the current position of the EGR valve stem, so that the return rate is reduced at a position close to the EGR valve seat, thereby achieving the effect of protecting parts.

Description

Technical Field

[0001] The invention relates to the technical field of internal combustion engine control, and in particular to a system for preventing an EGR valve stem from impacting a valve seat in an EGR system of an internal combustion engine. Background Art

[0002] Traditional gasoline engines usually use enrichment to reduce combustion temperature and NO in high-speed and high-load areas. x By introducing external EGR, the combustion temperature in high-speed and high-load areas can be reduced, and NO x On the one hand, it can improve the combustion in the medium-speed and medium-load area and improve the fuel economy.

[0003] However, in the low-load area, external EGR is not introduced considering combustion stability; in the low-speed and high-load area, external EGR cannot be introduced due to insufficient intake and exhaust pressure difference.

[0004] Therefore, in actual application, the operating conditions of the engine are constantly changing, and it is inevitable that the EGR will be frequently switched on and off. If it seats too quickly, it will cause impact and affect the durability of components. Summary of the invention

[0005] In view of this, the present invention provides an EGR exhaust gas recirculation slow-closing valve system and method, which uses a segmented multi-rate EGR valve stem group slow-closing valve strategy to solve the problem of EGR valve stem impacting the valve seat.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] An EGR exhaust gas recirculation slow closing valve method, characterized by comprising the steps of:

[0008] A: Get the actual position L of the EGR valve stem;

[0009] B: According to the actual position L, determine the position segment of the EGR valve stem; the position segment at least includes: the fully open position to the initial position L 初始 The first interval between the initial position L 初始 To the end position L 结束 The second interval between the initial position and the end position L 结束 between;

[0010] C: According to the position segment, the EGR valve stem is controlled to return at a corresponding rate; the return rate corresponding to the first interval is greater than the return rate corresponding to the second interval.

[0011] Preferably, in step B, the first interval is from the fully open position to the initial position L 初始 The PID closed loop free adjustment interval between the first and second intervals is the initial position L 初始 To the end position L 结束 The PID closed-loop slow speed adjustment interval between

[0012] The initial position L 初始 is the upper limit position of the slow seating control interval, and the end position L 结束 It is the lower limit position of the slow seating control range.

[0013] Preferably, step C comprises:

[0014] When the position segment is a PID closed-loop free adjustment interval, the target position L 目标 As the real-time target position L 实时 , and perform PID closed-loop control in combination with the actual position L, and adjust the EGR valve stem (5) to the target position L 目标 ;

[0015] When the position segment is a PID closed-loop slow speed adjustment interval, the initial position L 初始 As the real-time target position L 实时 , and the real-time target position L 实时 Subtract the step length L 步长 As the current real-time target position L 实时 , and perform PID closed-loop control in combination with the actual position L.

[0016] Preferably, in step B, the position segment further includes: an end position L 结束 The third interval between the fully closed position and the fully closed position;

[0017] The third interval is open-loop control, and is driven to zero with a fixed duty cycle.

[0018] Preferably, step C comprises:

[0019] When the position section is an open-loop seating interval, the EGR valve stem is open-loop controlled with a fixed driving duty ratio until it is fully closed and seated.

[0020] Preferably, step C comprises:

[0021] S1: Determine the target position L 目标 Is it smaller than the initial position L? 初始 If not, proceed to step S2; if yes, proceed to step S3;

[0022] S2: At target position L 目标 As the real-time target position L实时 , combined with the actual position L, PID closed-loop control is performed to adjust the EGR valve stem to the target position L 目标 ;

[0023] S3: At the initial position L 初始 As the real-time target position L 实时 , perform PID closed-loop control in combination with the actual position L, and adjust the EGR valve stem to the initial position L 初始 , then proceed to step S4;

[0024] S4: Determine the target position L 目标 Is it greater than the end position L? 结束 If yes, go to step S5; if no, go to step S6;

[0025] S5: Take the real-time target position L of step S3 实时 Subtract the step length L 步长 As the current real-time target position L 实时 , combined with the actual position L, PID closed-loop control is performed to adjust the EGR valve stem to the target position L 目标 ;

[0026] S6: Take the real-time target position L of step S3 实时 Subtract the step length L 步长 As the current real-time target position L 实时 , perform PID closed-loop control in combination with the actual position L, and adjust the EGR valve stem to the end position L 结束 , then proceed to step S7;

[0027] S7: Perform open-loop control with a fixed driving duty cycle to achieve full closing of the EGR valve stem.

[0028] Preferably, step A comprises:

[0029] The EGR valve stem position L is collected in real time through the EGR position sensor.

[0030] Preferably, before step A, the method further comprises the following steps:

[0031] When receiving the closing command, get the target position L 目标 , then go to step A.

[0032] An EGR exhaust gas recirculation slow-closing valve system adopts the above-mentioned EGR exhaust gas recirculation slow-closing valve method, comprising: an EGR position collector and a control module;

[0033] The EGR position collector can collect the actual position L of the EGR valve stem and send it to the control module;

[0034] The control module can determine the position segment of the EGR valve stem according to the actual position L; the position segment at least includes: the fully open position to the initial position L 初始 The PID closed loop free adjustment interval between the initial position L 初始 To the end position L 结束 The PID closed-loop slow speed adjustment interval between

[0035] The control module can also control the EGR valve stem to return at a corresponding rate according to the position segment; the return rate corresponding to the PID closed-loop slow speed adjustment interval is smaller than the return rate corresponding to the PID closed-loop free adjustment interval.

[0036] Preferably, the EGR position collector includes: an EGR position sensor, and / or the control module is integrated in an ECU controller.

[0037] It can be seen from the above technical solution that the EGR exhaust gas recirculation slow-closing valve system and method provided by the present invention collects the real-time EGR valve stem position and inputs it to the ECU controller, so that the ECU controller can control the EGR valve stem at different rates at different positions according to the current position of the EGR valve stem, thereby reducing the return rate at the position close to the EGR valve seat, thereby achieving the effect of protecting parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 A schematic diagram of the structure of an EGR system provided in an embodiment of the present invention;

[0040] Figure 2 A schematic diagram of position control of an EGR valve provided in an embodiment of the present invention;

[0041] Figure 3 A logic block diagram of the EGR valve seating control provided in an embodiment of the present invention.

[0042] Among them, 1. EGR valve drive motor; 2. small gear; 3. large gear; 4. cam; 5. EGR valve stem; 6. return spring; 7. EGR valve seat; 8. EGR position sensor; 9. ECU controller. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The EGR exhaust gas recirculation slow closing valve method provided in an embodiment of the present invention comprises the following steps:

[0045] A: Get the actual position L of the EGR valve stem 5;

[0046] B: According to the actual position L, determine the position segment of the EGR valve stem 5; the position segment at least includes: the fully open position to the initial position L 初始 The first interval between the initial position L 初始 To the end position L 结束 The second interval between the full open position and the end position L 结束 Between, such as Figure 2 As shown;

[0047] C: According to the position segment, control the EGR valve stem to return to the target position L at the corresponding rate 目标 ; The return rate corresponding to the first interval is greater than the return rate corresponding to the second interval.

[0048] It can be seen from the above technical solution that the EGR exhaust gas recirculation slow-closing valve system and method provided in the embodiment of the present invention collects the real-time position of the EGR valve stem 5 and inputs it to the ECU controller 9, so that the ECU controller 9 can control the EGR valve stem 5 at different rates at different positions according to the current position of the EGR valve stem 5, thereby reducing the return rate at the position close to the EGR valve seat 7, thereby achieving the effect of protecting parts.

[0049] Preferably, in step B, the first interval is from the fully open position to the initial position L 初始 The PID closed loop free adjustment interval between the first and second intervals is the initial position L 初始 To the end position L 结束 That is, the PID closed-loop free adjustment is performed in the first interval, and the PID closed-loop slow adjustment is performed in the second interval, so as to reduce the return rate at a position close to the EGR valve seat 7;

[0050] Initial position L 初始 The upper limit position of the slow seating control interval can be calibrated by those skilled in the art according to actual conditions. In this embodiment, it can be specifically 20% of the total opening of the EGR valve. The end position L 结束It is the lower limit position of the slow seating control range.

[0051] Further, step C comprises:

[0052] When the position segment is the PID closed loop free adjustment interval, the target position L 目标 As the real-time target position L 实时 , combined with the actual position L, PID closed-loop control is performed to adjust the EGR valve stem 5 to the target position L 目标 ;

[0053] When the position segment is the PID closed-loop slow speed adjustment interval, the initial position L 初始 As the real-time target position L 实时 , and the real-time target position L 实时 Subtract the step length L 步长 As the current real-time target position L 实时 , and perform PID closed-loop control in combination with the actual position L. This can achieve a speed reduction in the second interval relative to the first interval.

[0054] Specifically, in step B, the above position segment also includes: the end position L 结束 The third interval between the fully closed position and the fully closed position;

[0055] The third interval (from the end position to the zero position) is open-loop control, and is driven to the zero point with a fixed duty cycle (-20% in this project) to close the valve. The segmented multi-rate EGR valve stem group slow valve closing strategy of the present invention is further optimized.

[0056] In this embodiment, step C includes:

[0057] When the position section is the open-loop seating section, the EGR valve stem 5 is open-loop controlled with a fixed driving duty ratio until it is fully closed and seated. This arrangement enables segmented multi-rate control of the third section, the second section, and the first section.

[0058] like Figure 3 As described above, this scheme adopts judgment logic and step-by-step control, and its step C includes:

[0059] S1: Determine the target position L 目标 Is it smaller than the initial position L? 初始 If not, proceed to step S2; if yes, proceed to step S3;

[0060] S2: At target position L 目标 As the real-time target position L 实时 , combined with the actual position L, PID closed-loop control is performed to adjust the EGR valve stem 5 to the target position L 目标 ; Corresponding to the aforementioned first interval;

[0061] S3: At the initial position L 初始 As the real-time target position L 实时 , perform PID closed-loop control based on the actual position L, and adjust the EGR valve stem 5 to the initial position L 初始 , then proceed to step S4;

[0062] S4: Determine the target position L 目标 Is it greater than the end position L? 结束 If yes, go to step S5; if no, go to step S6;

[0063] S5: Take the real-time target position L of step S3 实时 Subtract the step length L 步长 As the current real-time target position L 实时 , combined with the actual position L, PID closed-loop control is performed to adjust the EGR valve stem 5 to the target position L 目标 ; Corresponding to the aforementioned second interval;

[0064] S6: Take the real-time target position L of step S3 实时 Subtract the step length L 步长 As the current real-time target position L 实时 , perform PID closed-loop control based on the actual position L, and adjust the EGR valve stem 5 to the end position L 结束 , then proceed to step S7;

[0065] S7: performing open-loop control with a fixed driving duty ratio to achieve full closing of the EGR valve stem 5; corresponding to the aforementioned third interval.

[0066] Preferably, step A comprises:

[0067] The position L of the EGR valve stem 5 is collected in real time by the EGR position sensor 8 .

[0068] Furthermore, before step A, the method further comprises the following steps:

[0069] When receiving the closing command, get the target position L 目标 , then go to step A;

[0070] The embodiment of the present invention further provides an EGR exhaust gas recirculation slow closing valve system, which adopts the above-mentioned EGR exhaust gas recirculation slow closing valve method, including: an EGR position collector and a control module;

[0071] The EGR position collector can collect the actual position L of the EGR valve stem 5 and send it to the control module;

[0072] The control module can determine the position segment of the EGR valve stem 5 according to the actual position L; the position segment at least includes: the fully open position to the initial position L 初始The PID closed loop free adjustment interval between the initial position L 初始 To the end position L 结束 The PID closed-loop slow speed adjustment interval between

[0073] The control module can also control the EGR valve stem 5 to return to its original position at a corresponding rate according to the position segment; the return rate corresponding to the PID closed-loop slow speed adjustment interval is smaller than the return rate corresponding to the PID closed-loop free adjustment interval.

[0074] Specifically, the EGR position collector includes: an EGR position sensor 8, and / or a control module integrated in the ECU controller 9, that is, it is integrated in the engine control system in the form of a software function module.

[0075] The present invention is further described below in conjunction with specific embodiments:

[0076] 1) According to different position control methods, the stroke of the EGR valve is divided into three intervals (see attached Figure 2 ): PID closed loop free adjustment range (full open position to initial position L 初始 )、PID closed loop slow speed adjustment interval (from the initial position L 初始 To the end position L 结束 )、Open-loop seating interval (end position L 结束 to the fully closed position).

[0077] 2) The present invention is applicable to the seating process of the EGR valve, so the actual position L of the EGR valve is greater than the target position L 目标 (The meaning of relevant symbols is shown in Appendix 1).

[0078] 3) When the target position L 目标 Greater than or equal to the initial position L 1 When the target position L 目标 As the real-time target position L 实时 , combined with the feedback signal of the EGR valve position sensor, PID closed-loop control is performed to adjust the EGR valve to the target position L 目标 .

[0079] 4) When the target position L 目标 Less than the initial position L 初始 , and is greater than the end position L 结束 When the position control is performed in steps: the first step is to take the initial position L 初始 As the real-time target position L 实时 , combined with the feedback signal of the EGR valve position sensor to perform PID closed-loop control; the second step is to use the real-time target position L 实时 Subtract the adjustment step length L 步长 As the current real-time target position L 实时, combined with the feedback signal of the EGR valve position sensor to perform PID closed-loop control; repeat the second step until the real-time target position L 实时 Reach the target position L 目标 ; Finally, PID closed-loop control adjusts EGR to the target position L 目标 .

[0080] 5) When the target position L 目标 Less than or equal to the end position L 结束 When the position control is performed in steps: the first step is to take the initial position L 初始 As the real-time target position L 实时 , combined with the feedback signal of the EGR valve position sensor to perform PID closed-loop control; the second step is to use the real-time target position L 实时 Subtract the step length L 步长 As the current real-time target position L 实时 , combined with the feedback signal of the EGR valve position sensor to perform PID closed-loop control; repeat the second step until the real-time target position L 实时 Reach end position L 结束 ; The third step is to perform open-loop control with a fixed driving duty cycle to achieve full closure of the EGR valve.

[0081] Appendix 1 Related symbols and their meanings

[0082] symbol meaning Actual location L The actual position of the EGR valve position sensor feedback <![CDATA[Initial position L 初始 > Upper limit position of the slow seating control range <![CDATA[End position L 结束 > The lower limit position of the slow-down control range <![CDATA[Target position L 目标 > Target required position of EGR valve <![CDATA[Real-time target position L 实时 > Target position used in PID position closed loop <![CDATA[Step length L 步长 > In the slow seat control, the adjustment step of the target position is used to limit the conditional speed of the EGR valve.

[0083] To summarize, the EGR exhaust gas recirculation slow-closing valve system and method provided by the present invention collects the real-time EGR valve stem position and inputs it to the ECU controller, so that the ECU controller can control the EGR valve stem at different rates at different positions according to the current position of the EGR valve stem, thereby reducing the return rate at the position close to the EGR valve seat, thereby achieving the effect of protecting parts.

[0084] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0085] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An EGR exhaust gas recirculation slow closing valve method, characterized in that: Includes steps: A: Get the actual position L of the EGR valve stem (5); B: According to the actual position L, determine the position segment of the EGR valve stem (5); the position segment at least includes: the fully open position to the initial position L 初始 The first interval between the initial position L 初始 To the end position L 结束 The second interval between the initial position and the end position L 结束 In step B, the first interval is from the fully open position to the initial position L 初始 The PID closed loop free adjustment interval between the first and second intervals is the initial position L 初始 To the end position L 结束 The PID closed-loop slow speed adjustment interval between the initial position L 初始 is the upper limit position of the slow seating control interval, and the end position L 结束 It is the lower limit position of the slow seating control range; C: according to the position segment, controlling the EGR valve stem (5) to return at a corresponding rate; the return rate corresponding to the first interval is greater than the return rate corresponding to the second interval; The step C comprises: S1: Determine the target position L 目标 Is it smaller than the initial position L? 初始 If not, proceed to step S2; if yes, proceed to step S3; S2: At target position L 目标 As the real-time target position L 实时 , and perform PID closed-loop control in combination with the actual position L, and adjust the EGR valve stem (5) to the target position L 目标 ; S3: At the initial position L 初始 As the real-time target position L 实时 , and perform PID closed-loop control in combination with the actual position L, and adjust the EGR valve stem (5) to the initial position L 初始 , then proceed to step S4; S4: Determine the target position L 目标 Is it greater than the end position L? 结束 If yes, go to step S5; if no, go to step S6; S5: Take the real-time target position L of step S3 实时 Subtract the step length L 步长 As the current real-time target position L 实时 , and perform PID closed-loop control in combination with the actual position L, and adjust the EGR valve stem (5) to the target position L 目标 ; S6: Take the real-time target position L of step S3 实时 Subtract the step length L 步长 As the current real-time target position L 实时 , and perform PID closed-loop control in combination with the actual position L, and adjust the EGR valve stem (5) to the end position L 结束 , then proceed to step S7; S7: performing open-loop control with a fixed driving duty cycle to achieve full closing of the EGR valve stem (5).

2. The EGR exhaust gas recirculation slow closing valve method according to claim 1, characterized in that: The step C comprises: When the position segment is a PID closed-loop free adjustment interval, the target position L 目标 As the real-time target position L 实时 , and perform PID closed-loop control in combination with the actual position L, and adjust the EGR valve stem (5) to the target position L 目标 ; When the position segment is a PID closed-loop slow speed adjustment interval, the initial position L 初始 As the real-time target position L 实时 , and the real-time target position L 实时 Subtract the step length L 步长 As the current real-time target position L 实时 , and perform PID closed-loop control in combination with the actual position L.

3. The EGR exhaust gas recirculation slow closing valve method according to claim 1, characterized in that: In step B, the position segment also includes: end position L 结束 The third interval between the fully closed position and the fully closed position; The third interval is open-loop control, and is driven to zero with a fixed duty cycle.

4. The EGR exhaust gas recirculation slow closing valve method according to claim 3, characterized in that: The step C comprises: When the position section is an open-loop seating interval, the EGR valve stem (5) is open-loop controlled with a fixed driving duty ratio until it is fully closed and seated.

5. The EGR exhaust gas recirculation slow closing valve method according to claim 1, characterized in that: The step A comprises: The position L of the EGR valve stem (5) is acquired in real time by means of the EGR position sensor (8).

6. The EGR exhaust gas recirculation slow closing valve method according to claim 1, characterized in that: Before step A, the method further comprises the following steps: When receiving the closing command, obtain the target position L 目标 , then go to step A.

7. An EGR exhaust gas recirculation slow closing valve system, characterized in that: The EGR exhaust gas recirculation slow closing valve method according to any one of claims 1 to 6 comprises: an EGR position collector and a control module; The EGR position collector can collect the actual position L of the EGR valve stem (5) and send it to the control module; The control module can determine the position segment of the EGR valve stem (5) according to the actual position L; the position segment at least includes: a fully open position to an initial position L 初始 The PID closed loop free adjustment interval between the initial position L 初始 To the end position L 结束 The PID closed-loop slow speed adjustment interval between The control module can also control the EGR valve stem (5) to return at a corresponding rate according to the position segment; the return rate corresponding to the PID closed-loop slow speed adjustment interval is smaller than the return rate corresponding to the PID closed-loop free adjustment interval.

8. The EGR exhaust gas recirculation slow closing valve system according to claim 7, characterized in that: The EGR position collector comprises: an EGR position sensor (8), and / or the control module is integrated in an ECU controller (9).

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