Tail gas treatment device for nitrogen oxide emission

Abstract

The utility model discloses a tail gas treatment device for nitrogen oxide emission, and relates to the field of tail gas treatment devices for nitrogen oxide emission. The tail gas treatment device for nitrogen oxide emission comprises a tail gas pipeline, a nitrogen oxide storage catalyst, a particulate matter catcher and a selective catalytic reduction catalyst are arranged on the tail gas pipeline, an upstream oxygen sensor is arranged on the upstream of the nitrogen oxide storage catalyst, and a nitrogen-oxygen sensor is arranged on the downstream of the nitrogen oxide storage catalyst. According to the tail gas treatment device for nitrogen oxide emission, a downstream oxygen sensor is omitted at the downstream of the nitrogen oxide storage catalyst, an original nitrogen-oxygen sensor on a vehicle is used for detecting the oxygen concentration and confirming whether regeneration is finished or not, and the nitrogen-oxygen sensor is used for replacing the downstream oxygen sensor, so that the target of replacing the oxygen sensor with a single sensor is achieved; meanwhile, the function of the nitrogen-oxygen sensor is upgraded, and technical reserve is provided for subsequent emission upgrading.

Description

Technical Field

[0001] This utility model relates to the technical field of exhaust gas treatment devices for nitrogen oxide emissions, specifically an exhaust gas treatment device for nitrogen oxide emissions. Background Technology

[0002] Exhaust gas treatment devices for nitrogen oxide emissions are a key technology for reducing nitrogen oxide emissions from diesel vehicle exhaust.

[0003] Nitrogen oxide sensors are mainly used in diesel vehicles. By detecting the concentration of nitrogen oxides and oxygen in the exhaust gas, they assist the ECU in optimizing combustion and selective catalytic reduction. Traditional oxygen sensors, on the other hand, directly provide feedback on the air-fuel ratio by detecting the oxygen concentration.

[0004] The existing aftertreatment solution requires adding an oxygen sensor after the nitrogen oxide emission treatment device to determine whether the nitrogen oxide emission treatment device has finished regeneration by detecting the air-fuel ratio. This requires the use of an additional oxygen sensor to make the judgment, and the existing nitrogen-oxygen sensor cannot replace this function, resulting in a waste of resources. The nitrogen-oxygen sensor also has the function of measuring oxygen concentration. Under the critical operating condition of air-fuel ratio λ=1, the IP1 current signal of the nitrogen-oxygen sensor will exhibit abnormal fluctuations. This fluctuation affects the oxygen concentration detected by the nitrogen-oxygen sensor. To repair and improve this fluctuation, the downstream oxygen sensor should be eliminated and replaced with the nitrogen-oxygen sensor.

[0005] This application proposes an exhaust gas treatment device for nitrogen oxide emissions, which eliminates the need for an oxygen sensor and replaces it with the vehicle's existing nitrogen oxide sensor. Through improvements in electrode materials, dynamic signal processing, and system-level integration, the IP1 signal fluctuation problem of the nitrogen oxide sensor at λ=1 is overcome, significantly improving its accuracy, cost, and regulatory compliance. This achieves the goal of replacing the oxygen sensor with a single sensor, providing a new path for integrated emission control of future hybrid and hydrogen fuel cell vehicles. Utility Model Content

[0006] To address the shortcomings of existing technologies, this utility model provides a tail gas treatment device for nitrogen oxide emissions. This solves the problem that existing aftertreatment solutions require the addition of an oxygen sensor after the nitrogen oxide emission tail gas treatment device to determine whether the nitrogen oxide emission tail gas treatment device has finished regeneration by detecting the air-fuel ratio. This requires the use of an additional oxygen sensor to make the judgment, and the existing nitrogen-oxygen sensor cannot be used to replace this function, resulting in a waste of resources.

[0007] To achieve the above objectives, this utility model provides the following technical solution: a tail gas treatment device for nitrogen oxide emissions, comprising a tail gas pipeline, wherein a nitrogen oxide storage catalyst, a particulate matter trap, and a selective catalytic reduction catalyst are installed on the tail gas pipeline, an upstream oxygen sensor is installed upstream of the nitrogen oxide storage catalyst, and a nitrogen-oxygen sensor is installed downstream of the nitrogen oxide storage catalyst, wherein the nitrogen-oxygen sensor is used to detect the oxygen concentration and determine whether the nitrogen oxide storage catalyst has finished regeneration.

[0008] Preferably, a T4 exhaust temperature sensor is provided upstream of the nitrogen oxide storage catalyst, and the T4 exhaust temperature sensor measures the exhaust temperature entering the oxidation catalyst.

[0009] Preferably, a T5 exhaust temperature sensor is installed downstream of the nitrogen oxide storage catalyst, and the T5 exhaust temperature sensor provides real-time feedback on the intake temperature of the particulate filter.

[0010] Preferably, a T6 exhaust temperature sensor is provided downstream of the particulate matter trap, the T6 exhaust temperature sensor monitoring the exhaust temperature before selective catalytic reduction.

[0011] Preferably, a catalytic converter exhaust tailpipe is provided downstream of the selective catalytic reduction catalyst.

[0012] Preferably, a downstream oxygen sensor is eliminated downstream of the nitrogen oxide storage catalyst.

[0013] This utility model discloses a tail gas treatment device for nitrogen oxide emissions, which has the following beneficial effects:

[0014] This exhaust gas treatment device for nitrogen oxide emissions eliminates the downstream oxygen sensor from the nitrogen oxide storage catalyst. Instead, it uses the vehicle's existing nitrogen oxide sensor to detect oxygen concentration and determine whether regeneration has ended. By replacing the downstream oxygen sensor with a nitrogen oxide sensor, the goal of replacing the oxygen sensor with a single sensor is achieved, thereby reducing costs. At the same time, the functionality of the nitrogen oxide sensor is upgraded, laying the groundwork for future emission upgrades. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the overall structure of this embodiment;

[0017] Figure 2 This is a schematic diagram of the existing exhaust gas pipeline structure;

[0018] Figure 3 This is a fluctuation diagram of the nitrogen and oxygen sensor in this embodiment;

[0019] Figure 4 This is a diagram showing the internal software correction of the nitrogen and oxygen sensor in this embodiment.

[0020] In the diagram: 1. Exhaust pipe; 11. T4 exhaust temperature sensor; 12. T5 exhaust temperature sensor; 13. T6 exhaust temperature sensor; 14. Catalytic converter exhaust tailpipe; 2. Nitrogen oxide storage catalyst; 3. Particulate matter trap; 4. Selective catalytic reduction catalyst; 5. Upstream oxygen sensor; 6. Downstream oxygen sensor; 7. Nitrogen oxide sensor. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments of this utility model are described clearly and completely. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] This application provides a nitrogen oxide emission exhaust gas treatment device, which solves the problem that existing aftertreatment solutions require an additional oxygen sensor after the nitrogen oxide emission exhaust gas treatment device to determine whether the nitrogen oxide emission exhaust gas treatment device has stopped regeneration by detecting the air-fuel ratio. This requires the use of an additional oxygen sensor to make the judgment, and the existing nitrogen-oxygen sensor 7 cannot replace this function, resulting in resource waste. The present application eliminates the need for a downstream oxygen sensor 6 downstream of the nitrogen oxide storage catalyst 2, and uses the vehicle's existing nitrogen-oxygen sensor 7 to detect the oxygen concentration and confirm whether regeneration has ended. The nitrogen-oxygen sensor 7 replaces the downstream oxygen sensor 6, achieving the goal of replacing the oxygen sensor with a single sensor, thereby reducing costs. At the same time, it upgrades the function of the nitrogen-oxygen sensor 7, laying the technical foundation for future emission upgrades.

[0023] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0024] This utility model discloses a tail gas treatment device for nitrogen oxide emissions.

[0025] According to the appendix Figure 1-4As shown, it includes an exhaust pipe 1, on which a nitrogen oxide storage catalyst 2, a particulate matter trap 3 and a selective catalytic reduction catalyst 4 are installed. An upstream oxygen sensor 5 is installed upstream of the nitrogen oxide storage catalyst 2, and a nitrogen-oxygen sensor 7 is installed downstream of the nitrogen oxide storage catalyst 2. The nitrogen-oxygen sensor 7 is used to detect the oxygen concentration and determine whether the nitrogen oxide storage catalyst 2 has finished regenerating.

[0026] Downstream of the nitrogen oxide storage catalyst 2, the downstream oxygen sensor 6 is eliminated. Instead, the vehicle's existing nitrogen oxide sensor 7 is used to detect the oxygen concentration and confirm whether regeneration has ended. Replacing the downstream oxygen sensor 6 with the nitrogen oxide sensor 7 achieves the goal of replacing the oxygen sensor with a single sensor, thereby reducing costs. At the same time, the function of the nitrogen oxide sensor 7 is upgraded, laying the technical groundwork for subsequent emission upgrades.

[0027] A T4 exhaust temperature sensor 11 is installed upstream of the nitrogen oxide storage catalyst 2. The T4 exhaust temperature sensor 11 measures the exhaust temperature entering the oxidation catalyst and provides initial temperature data for the oxidation reaction in the oxidation catalyst.

[0028] Downstream of the nitrogen oxide storage catalyst 2 is a T5 exhaust temperature sensor 12, which provides real-time feedback on the particulate filter intake temperature. The T5 exhaust temperature sensor 12 is used to calculate the carbon loading and trigger the particulate filter regeneration strategy.

[0029] Downstream of the particulate matter trap 3 is a T6 exhaust temperature sensor 13, which monitors the exhaust temperature before selective catalytic reduction and ensures that the urea injection system operates at a suitable temperature.

[0030] Downstream of the selective catalytic reduction catalyst 4 is a catalytic converter exhaust tailpipe 14, which detects the final emission temperature, evaluates the overall aftertreatment efficiency, and compares it with regulatory limits.

[0031] The downstream oxygen sensor 6 is removed from the downstream of the nitrogen oxide storage catalyst 2, and the nitrogen oxide sensor 7, which is downstream of the particulate matter trap 3, is set downstream of the nitrogen oxide storage catalyst 2 to detect the oxygen concentration.

[0032] During the regeneration of the nitrogen oxide storage catalyst 2, both oxygen and nitrogen oxides are generated simultaneously. The oxygen concentration is detected by the downstream oxygen sensor 6 to determine whether the regeneration has ended.

[0033] This application uses the vehicle's existing nitrogen-oxygen sensor 7 to detect oxygen concentration and confirm whether regeneration has ended. By replacing the downstream oxygen sensor 6 with the nitrogen-oxygen sensor 7, the goal of replacing the oxygen sensor with a single sensor is achieved, thereby reducing costs. At the same time, the function of the nitrogen-oxygen sensor 7 is upgraded, laying the technical groundwork for subsequent emission upgrades.

[0034] When oxygen is detected by nitrogen-oxygen sensor 7, there is a fluctuation in the current signal IP1 when the air-fuel ratio is equal to 1. This fluctuation affects the concentration of oxygen detected by nitrogen-oxygen sensor 7.

[0035] The method described in this application is used in conjunction with the overshoot correction scheme for the current signal of the nitrogen and oxygen sensor 7IP1;

[0036] The process for overshoot correction of the 7IP1 nitrogen and oxygen sensor current signal is as follows:

[0037] S1. Problem Identification

[0038] Overshoot detection: The oscillation amplitude and frequency of IP1 current under the condition of λ=1 are recorded by testing with a calibration box, and the overshoot threshold is determined by comparing it with the standard sensor data.

[0039] The overshoot phenomenon is caused by the non-uniformity of the nanoscale electrode coating leading to an imbalance in charge distribution, the high concentration of NOx > 560 ppm triggering a cross-sensitivity effect, and the temperature control system fluctuation of ±5℃ amplifying the substrate noise.

[0040] S2. Scheme Design

[0041] S2.1 Hardware-Software Co-working Architecture

[0042] UP1 control logic: The output is adjusted in real time using a dynamic gain coefficient k ranging from 0.8 to 1.2. The NOx compensation factor α is determined by calibration atmosphere point experiments, with α = 0.05-0.15.

[0043] Temperature compensation circuit: Integrated PID heater, which controls the operating temperature fluctuation within ±1℃.

[0044] S2.2 Software Algorithm Optimization

[0045] Feedforward compensation: The UP1 signal is corrected in advance based on the NOx concentration prediction model;

[0046] Adaptive filtering: The RLS algorithm is used to eliminate high-frequency noise above 200Hz;

[0047] MPC control: Optimizes IP1 current tracking trajectory with a period of 10ms;

[0048] Parameter calibration: The k / α combination was optimized at four calibration atmosphere points using the PSO algorithm, and the results were burned into the EEPROM.

[0049] S2.3 Hardware Enhancement

[0050] Electrode modification: A yttrium oxide-stabilized nanoporous coating is used to reduce polarization resistance;

[0051] Temperature control upgrade: Three-channel thermocouple + digital PID controller, resulting in a response time of <50ms.

[0052] S3. Verification Process

[0053] Calibration test: Verify the overshoot suppression effect under 60ppm / 560ppm NOx conditions, requiring current fluctuation <0.1μA;

[0054] Durability test: Continuous operation under λ=1 condition for 100 hours to ensure parameter drift <5%.

[0055] By modifying the internal software of the nitrogen-oxygen sensor 7IP1 to correct the overshoot of the current signal, the overshoot phenomenon is improved by using UP1 to correct the current signal IP1, thereby achieving the effects of filtering and de-scratching, resulting in a smooth waveform.

[0056] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A tail gas treatment device for nitrogen oxide emissions, characterized in that, The device includes an exhaust pipe (1), on which a nitrogen oxide storage catalyst (2), a particulate matter trap (3) and a selective catalytic reduction catalyst (4) are installed. An upstream oxygen sensor (5) is installed upstream of the nitrogen oxide storage catalyst (2), and a nitrogen-oxygen sensor (7) is installed downstream of the nitrogen oxide storage catalyst (2). The nitrogen-oxygen sensor (7) is used to detect the oxygen concentration and determine whether the nitrogen oxide storage catalyst (2) has finished regenerating.

2. The tail gas treatment device for nitrogen oxide emissions according to claim 1, characterized in that, A T4 exhaust temperature sensor (11) is provided upstream of the nitrogen oxide storage catalyst (2), which measures the exhaust temperature entering the oxidation catalyst.

3. The tail gas treatment device for nitrogen oxide emissions according to claim 1, characterized in that, A T5 exhaust temperature sensor (12) is provided downstream of the nitrogen oxide storage catalyst (2), and the T5 exhaust temperature sensor (12) provides real-time feedback on the intake temperature of the particulate filter.

4. The tail gas treatment device for nitrogen oxide emissions according to claim 1, characterized in that, A T6 exhaust temperature sensor (13) is provided downstream of the particulate matter trap (3), which monitors the exhaust temperature before selective catalytic reduction.

5. The exhaust gas treatment device for nitrogen oxide emissions according to claim 1, characterized in that, A catalytic converter exhaust tailpipe (14) is provided downstream of the selective catalytic reduction catalyst (4).

6. The tail gas treatment device for nitrogen oxide emissions according to claim 1, characterized in that, The downstream oxygen sensor (6) is removed from the nitrogen oxide storage catalyst (2).

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