A diesel engine SDPF temperature control system and control method based on dynamic airflow distribution

Abstract

The present invention provides a diesel engine SDPF temperature control system and a control method based on dynamic airflow distribution. The diesel engine SDPF temperature control system based on dynamic airflow distribution includes a carrier assembly, a detection assembly and a control unit; the carrier assembly includes a tube body and a carrier part arranged in the tube body, the carrier part includes an outer ring carrier and a central carrier sleeved in the outer ring carrier, the central carrier and the outer ring carrier are coaxially arranged, and the central carrier and the outer ring carrier are slidably connected; the detection assembly includes a first temperature sensor, a second temperature sensor and a third temperature sensor, the control unit is electrically connected to the detection assembly, and the control unit is used to control the sliding of the central carrier. Under the cold start condition of the engine, the control unit drives the central carrier to move axially toward the tube body inlet to increase the temperature of the central carrier. When entering the regeneration / exhaust working stage, the control unit controls it to move axially away from the tube body inlet to reduce the risk of thermal stress-induced damage to the carrier assembly.

Description

Technical Field

[0001] The present invention relates to the technical field of power engineering, and in particular to a diesel engine SDPF temperature control system and a control method based on dynamic airflow distribution. Background Art

[0002] Diesel engines, with their excellent power and economy, are widely used in transportation, agricultural machinery, and construction machinery. However, they produce high levels of particulate matter and nitrogen oxides (NOx) emissions, significantly polluting the atmosphere and posing a significant threat to public health.

[0003] However, during the cold start phase, conventional selective catalytic reduction particulate trapping (SDPF) technology fails to purify NOx because the carrier temperature is lower than the SCR catalyst ignition temperature (usually >200°C). In addition, there is the problem of uneven heat distribution: the temperature in the central area easily exceeds the limit (the typical SCR catalyst high efficiency range is 350-450°C). The temperature difference leads to differences in the soot oxidation rate, exacerbating local overheating and the risk of thermal stress causing carrier damage. Summary of the Invention

[0004] In view of the deficiencies in the prior art, the present invention aims to provide a permanent magnet limited-angle motor, aiming to solve the technical problems mentioned in the background technology.

[0005] In view of the above situation, a diesel engine SDPF temperature control system and control method based on dynamic airflow distribution are provided, aiming to solve the technical problems mentioned in the background technology.

[0006] A diesel engine SDPF temperature control system based on dynamic airflow distribution includes a carrier component, a detection component and a control unit;

[0007] The carrier assembly includes a tube body and a carrier portion disposed in the tube body, the carrier portion includes an outer ring carrier and a center carrier sleeved in the outer ring carrier, the center carrier and the outer ring carrier are coaxially arranged, and the center carrier and the outer ring carrier are slidably connected;

[0008] The detection assembly includes a first temperature sensor, a second temperature sensor, and a third temperature sensor. The first temperature sensor is provided at the inlet of the tube, the second temperature sensor is provided at one end of the central carrier facing the outlet of the tube, and the third temperature sensor is provided at the outlet of the tube.

[0009] The control unit is electrically connected to the detection component, and the control unit is used to control the sliding of the central carrier.

[0010] Beneficial effects of the present invention:

[0011] During an engine cold start, if the first temperature value of the first temperature sensor is detected to be below a first preset threshold, the control unit drives the central carrier to move axially toward the tube inlet. This regulation mechanism raises the temperature of the central carrier, thereby improving the NOx conversion efficiency of the carrier by over 20%. During the regeneration / exhaust phase, if the central carrier temperature is too high and the first temperature value of the first temperature sensor is detected to be no less than a first preset threshold, the control unit divides the difference between the second and third temperature values ​​by the difference between the third and first temperature values ​​to obtain a first ratio. This ratio is then compared with a second preset threshold. If the first ratio is greater than the second preset threshold, the control unit controls the carrier to move axially away from the tube inlet. This regulation strategy reduces the risk of carrier ablation caused by high temperatures while also increasing the overall heat dissipation area of ​​the carrier, thereby avoiding local overheating and reducing the risk of thermal stress-induced damage to the carrier.

[0012] Furthermore, the central carrier and the outer ring carrier have the same axial length.

[0013] Furthermore, the length of the central carrier protruding from the outer ring carrier does not exceed 50% of the axial length of the central carrier.

[0014] Furthermore, the thickness of the outer ring carrier is:

[0015] ΔR=(D-Dc) / 2;

[0016] Where D is the diameter of the outer ring carrier, and Dc is the diameter of the central carrier.

[0017] Furthermore, the inner wall of the tube body is raised to form arc-shaped contraction openings arranged opposite to each other, and the two arc-shaped contraction openings are located between the inlet of the tube body and the outer ring carrier, and the two arc-shaped contraction openings are adjacent to the outer ring carrier.

[0018] Furthermore, the ratio of the cross-sectional area of ​​the end of the arc-shaped contraction port close to the tube body inlet to the cross-sectional area of ​​the end close to the central carrier is 0.5-0.8.

[0019] The present invention also provides a control method for a diesel engine SDPF temperature control system based on dynamic airflow distribution, characterized in that the control method adopts the above-mentioned SDPF temperature control system based on dynamic airflow distribution, and the control method includes the following steps:

[0020] S1: Connecting the tube body of the carrier assembly to the exhaust valve of the diesel engine, collecting first, second, and third temperature values ​​of the airflow at corresponding positions in real time using the first, second, and third temperature sensors of the detection assembly, and transmitting the first, second, and third temperature values ​​to a control unit;

[0021] S2: During a cold start condition of the engine, the control unit compares the first temperature value with a first preset threshold value. When the first temperature value is less than the first preset threshold value, the control unit controls the central carrier of the carrier portion to move axially toward the inlet of the tube body.

[0022] S3: When the carrier part enters the regeneration / exhaust working stage, the control unit compares the first temperature value with a first preset threshold value. When the first temperature value is greater than or equal to the first preset threshold value, the control unit divides the difference between the second temperature value and the third temperature value by the difference between the third temperature value and the first temperature value to obtain a first ratio, and compares the first ratio with a second preset threshold value. When the first ratio is greater than the second preset threshold value, the control unit controls the central carrier of the carrier part to move along the axial direction toward the outlet of the tube body; when the first ratio is less than the second preset threshold value, the control unit controls the central carrier of the carrier part to move along the axial direction to reset. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0024] Figure 1 Schematic diagram of the structure of the carrier component and the detection component of the first embodiment of the present invention Figure 1 ;

[0025] Figure 2 Schematic diagram of the structure of the carrier component and the detection component of the first embodiment of the present invention Figure 2 ;

[0026] Figure 3 is a cross-sectional view of a carrier assembly according to a first embodiment of the present invention;

[0027] Figure 4 Schematic diagram of a flow chart of a control method for a diesel engine SDPF temperature control system based on dynamic airflow distribution according to a second embodiment of the present invention.

[0028] In the figure: 1. Carrier assembly; 11. Tube body; 12. Carrier portion; 121. Outer ring carrier; 122. Center carrier; 13. Arc-shaped contraction port; 2. Detection assembly; 21. First temperature sensor; 22. Second temperature sensor; 23. Third temperature sensor.

[0029] The embodiments of the present invention will be further described below with reference to the accompanying drawings. DETAILED DESCRIPTION

[0030] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the embodiments of the present invention, and should not be understood as limiting the present invention.

[0031] In the description of the embodiments of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0033] Example 1

[0034] See also Figures 1 to 3 , a diesel engine SDPF temperature control system based on dynamic airflow distribution, including a carrier component 1, a detection component 2 and a control unit (not shown).

[0035] Specifically, the carrier assembly 1 includes a tube body 11 and a carrier portion 12 disposed in the tube body 11. The carrier portion 12 includes an outer ring carrier 121 and a central carrier 122 sleeved in the outer ring carrier 121. The central carrier 122 is coaxially arranged with the outer ring carrier 121 and is slidably connected to the outer ring carrier 121.

[0036] The detection assembly 2 includes a first temperature sensor 21, a second temperature sensor 22, and a third temperature sensor 23. The first temperature sensor 21 is located at the inlet of the tube 11, the second temperature sensor 22 is located at one end of the central carrier 122 facing the outlet of the tube 11, and the third temperature sensor 23 is located at the outlet of the tube 11.

[0037] The control unit is electrically connected to the detection assembly 2 , and is used to control the sliding of the central carrier 122 .

[0038] It should be noted that the tube body 11 of the carrier portion 12 is connected to the exhaust valve of the diesel engine, and the first temperature sensor 21, the second temperature sensor 22 and the third temperature sensor 23 of the detection component 2 are used to collect the first temperature value, the second temperature value and the third temperature value of the airflow at the corresponding position in real time, and the first temperature value, the second temperature value and the third temperature value are transmitted to the control unit. Under the cold start condition of the engine, when the first temperature value of the first temperature sensor 21 is detected to be lower than the first preset threshold value, the control unit drives the central carrier 122 to slide axially toward the inlet of the tube body 11. Since the temperature of the airflow near the inlet of the tube body 11 is high, the adjustment mechanism can increase the temperature of the central carrier 122, thereby increasing the temperature of the central carrier 122. The temperature is conducive to the ignition of the SCR catalyst, thereby improving the NOx conversion efficiency of the carrier part 12 by more than 20%; when the carrier part 12 enters the regeneration / exhaust working stage, when the first temperature value is greater than or equal to the first preset threshold, the control unit divides the difference between the second temperature value and the third temperature value by the difference between the third temperature value and the first temperature value to obtain a first ratio, and compares the first ratio with the second preset threshold. If the first ratio is greater than the second preset threshold, the control unit controls the central carrier 122 to move axially away from the inlet of the tube body 11. This adjustment strategy can reduce the risk of ablation of the carrier part 12 due to high temperature, and at the same time increase the overall heat dissipation area of ​​the carrier part 12, thereby avoiding local overheating and reducing the risk of damage to the carrier part 12 caused by thermal stress.

[0039] It is worth mentioning that the cross-sections at the opposite ends of the outer ring carrier 121 and the central carrier 122 include multiple air flow channels, which allow the air flow to pass through the outer ring carrier 121 and the central carrier 122; the first temperature sensor 21 and the third temperature sensor 23 are arranged on the inner wall of the tube body 11, and the second temperature sensor 22 is arranged on the end face of the central carrier 122 facing the outlet of the tube body 11.

[0040] In addition, the control unit is embedded in the existing vehicle control system, which makes it easy to operate and control.

[0041] Specifically, the central carrier 122 and the outer ring carrier 121 have the same axial length, ensuring that both ends of the central carrier 122 are flush with the outer ring carrier 121 when the central carrier 122 is reset.

[0042] Specifically, the length of the center carrier 122 protruding from the outer ring carrier 121 does not exceed 50% of the axial length of the center carrier 122. This limitation ensures that the center carrier 122 will not exceed the physical boundary of the outer ring carrier 121 when moving, thereby avoiding being unable to reset and affecting subsequent use. Of course, this can be achieved by setting a limit sensor in the prior art, which will not be elaborated here.

[0043] Specifically, the thickness of the outer ring carrier 121 is:

[0044] ΔR=(D-Dc) / 2;

[0045] Wherein, D is the diameter of the outer ring carrier 121, and Dc is the diameter of the central carrier 122. The outer ring carrier 121 and the central carrier 122 are concentrically arranged, and the inner wall of the outer ring carrier 121 abuts the outer wall of the central carrier 122, so that the exhaust gas flow can pass through the central carrier 122 and the outer ring carrier 121 evenly.

[0046] Specifically, the inner wall of the tube body 11 is raised to form relatively arranged arc-shaped contraction openings 13. The two arc-shaped contraction openings 13 are located between the inlet of the tube body 11 and the outer ring carrier 121. The two arc-shaped contraction openings 13 are adjacent to the outer ring carrier 121. The distance (calculated based on the radial cross-section at the midpoint of the arc-shaped contraction opening 13 and the end face at the exhaust inlet of the outer ring carrier 121) is preferably set at 1.05 times to 2 times the moving distance of the center carrier 122. Such a setting can make more exhaust airflow more concentrated.

[0047] Specifically, the ratio of the inlet cross-sectional area to the outlet cross-sectional area of ​​the arc-shaped contraction port 13 is 0.6, so that when the central carrier 122 is close to the inlet of the tube body 11, the exhaust airflow is more concentrated. For the engine cold start condition, such a setting can allow more exhaust airflow to flow to the central carrier 122, thereby more quickly increasing the temperature of the central carrier 122 and shortening the ignition time of the SCR catalyst; when the central carrier 122 is in the reset state or close to the outlet of the tube body 11, the exhaust airflow can evenly enter the central carrier 122 and the outer ring carrier 121.

[0048] In this embodiment, data such as exhaust flow, temperature, and gas concentration at the SDPF inlet under typical operating conditions (cold start, idle, and high load) obtained from engine bench testing were input for calculation. Under cold start conditions, the central carrier 122 was positioned at the exhaust inlet of the tube body 11. The integrated SDPF carrier took 118 seconds to heat up from 100K to 300K, compared to 36 seconds in this embodiment, shortening the temperature rise time by 69%. Under cold start conditions (0-150 seconds), the integrated SDPF carrier achieved a comprehensive NOx conversion rate of 21.2%, compared to 68.4% in this embodiment. The SDPF carrier carbon loading was set at 5g / L. After active regeneration was initiated under high load conditions and then entered idle conditions, the integrated SDPF carrier achieved a maximum temperature difference of 146K, compared to 83K in this embodiment, a 47% reduction in the maximum temperature difference of the carrier portion 12.

[0049] Example 2

[0050] See also Figure 4, the present invention also provides a control method for a diesel engine SDPF temperature control system based on dynamic air flow distribution. The control method uses the SDPF temperature control system based on dynamic air flow distribution as described above. Please refer to Figures 1 to 3 , and the control method includes the following steps:

[0051] S1: Connect the tube body 11 of the carrier component 1 to the diesel engine exhaust valve. Based on the first temperature sensor 21, the second temperature sensor 22, and the third temperature sensor 23 of the detection component 2, collect the first temperature value, the second temperature value, and the third temperature value of the air flow at the corresponding positions in real time, and transmit the first temperature value, the second temperature value, and the third temperature value to the control unit;

[0052] S2: During the cold start condition of the engine, the control unit compares the first temperature value with the first preset threshold. When the first temperature value is less than the first preset threshold, the control unit controls the central carrier 122 of the carrier part 12 to move axially towards the inlet of the tube body 11;

[0053] S3: When the carrier part 12 enters the regeneration / exhaust working stage, the control unit compares the first temperature value with the first preset threshold. When the first temperature value is greater than or equal to the first preset threshold, the control unit divides the difference between the second temperature value and the third temperature value by the difference between the third temperature value and the first temperature value to obtain a first ratio, and compares the first ratio with the second preset threshold. When the first ratio is greater than the second preset threshold, the control unit controls the central carrier 122 of the carrier part 12 to move axially towards the outlet of the tube body 11; when the first ratio is less than the second preset threshold, the control unit controls the central carrier 122 of the carrier part 12 to move axially to reset, so that the two ends of the central carrier 122 and the outer ring carrier 121 are flush.

[0054] The pseudocode of the control method is:

[0055] if (T_in<T_low) { / / Cold start mode

[0056] center_shift = +l_max

[0057] while (T_center<SCR_active_temp) {

[0058] center_shift -= Δl (step size)

[0059] delay(t_interval)

[0060] }

[0061] } else if ((T_out1 - T_out) / (T_out - T_in)>a_threshold) { / / Thermal balance mode

[0062] center_shift = -l_adjust (proportional adjustment)

[0063] if (ΔP>P_max) { / / Flow resistance protection

[0064] limit_shift_rate

[0065] }

[0066] }

[0067] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0068] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A diesel engine SDPF temperature control system based on dynamic airflow distribution, characterized by: It includes a carrier component, a detection component and a control unit; The carrier assembly includes a tube body and a carrier portion disposed in the tube body, the carrier portion includes an outer ring carrier and a center carrier sleeved in the outer ring carrier, the center carrier and the outer ring carrier are coaxially arranged, and the center carrier and the outer ring carrier are slidably connected; The detection assembly includes a first temperature sensor, a second temperature sensor, and a third temperature sensor. The first temperature sensor is provided at the inlet of the tube, the second temperature sensor is provided at one end of the central carrier facing the outlet of the tube, and the third temperature sensor is provided at the outlet of the tube. The control unit is electrically connected to the detection assembly, and the control unit is used to control the sliding of the central carrier; The control method of the diesel engine SDPF temperature control system includes the following steps: S1: Connecting the tube body of the carrier assembly to the exhaust valve of the diesel engine, collecting first, second, and third temperature values ​​of the airflow at corresponding positions in real time using the first, second, and third temperature sensors of the detection assembly, and transmitting the first, second, and third temperature values ​​to a control unit; S2: During a cold start condition of the engine, the control unit compares the first temperature value with a first preset threshold value. When the first temperature value is less than the first preset threshold value, the control unit controls the central carrier of the carrier portion to move axially toward the inlet of the tube body. S3: When the carrier part enters the regeneration / exhaust working stage, the control unit compares the first temperature value with a first preset threshold value. When the first temperature value is greater than or equal to the first preset threshold value, the control unit divides the difference between the second temperature value and the third temperature value by the difference between the third temperature value and the first temperature value to obtain a first ratio, and compares the first ratio with a second preset threshold value. When the first ratio is greater than the second preset threshold value, the control unit controls the central carrier of the carrier part to move along the axial direction toward the outlet of the tube body; when the first ratio is less than the second preset threshold value, the control unit controls the central carrier of the carrier part to move along the axial direction to reset.

2. The diesel engine SDPF temperature control system based on dynamic airflow distribution according to claim 1, characterized in that: The central carrier and the outer ring carrier have the same axial length.

3. The diesel engine SDPF temperature control system based on dynamic airflow distribution according to claim 2, characterized in that: The length of the central carrier protruding from the outer ring carrier does not exceed 50% of the axial length of the central carrier.

4. The diesel engine SDPF temperature control system based on dynamic airflow distribution according to claim 1, characterized in that: The thickness of the outer ring carrier is: ΔR=(D-Dc) / 2; Where D is the diameter of the outer ring carrier, and Dc is the diameter of the central carrier.

5. The diesel engine SDPF temperature control system based on dynamic airflow distribution according to claim 1, characterized in that: The inner wall of the tube body is raised to form arc-shaped contraction openings which are arranged opposite to each other. The two arc-shaped contraction openings are located between the inlet of the tube body and the outer ring carrier, and the two arc-shaped contraction openings are adjacent to the outer ring carrier.

6. The diesel engine SDPF temperature control system based on dynamic airflow distribution according to claim 5, characterized in that: The ratio of the cross-sectional area of ​​the end of the arc-shaped contraction port close to the tube body inlet to the cross-sectional area of ​​the end close to the central carrier is 0.5-0.8.

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