Control device and method for real-time avoidance of catalyst hc poisoning

Abstract

The application discloses a kind of control device and method for avoiding catalyst HC poisoning in real time, and control method includes: obtaining the HC emission under different working conditions, and establishing the steady-state model of HC emission;Determine the correction coefficient of HC in transient acceleration process;Determine the conversion efficiency of the current catalyst HC;According to the characteristics of catalyst and the linearity of emission, determine the minimum efficiency limit of the HC accumulation amount when the conversion efficiency of catalyst is allowed;By adjusting the injection parameters of engine, timing, rail pressure, throttle, post-injection amount makes the temperature sensed by catalytic T4 temperature sensor greater than 300 DEG C;And real-time evaluation of the current conversion efficiency of catalyst, and calculate the current HC accumulation amount, until the HC accumulation amount is less than the limit of HC accumulation amount.By this means, not only can HC in catalyst be removed by reasonable control strategy, restore the conversion efficiency of catalyst, but also can reduce the trigger limit torque strategy, reduce user's complaint.

Description

Technical Field

[0001] This invention relates to the field of engine design and manufacturing, and in particular to a control device and method for real-time prevention of HC poisoning in catalytic converters. Background Technology

[0002] With increasingly stringent emission regulations, China VI diesel engines utilize complex after-treatment systems to reduce emissions of pollutants such as NOx, PM, and PN. However, due to the complex operating environments and inconsistent fuel quality, catalytic converter poisoning occurs, leading to decreased efficiency. This causes emissions to exceed OBD alarm limits, triggering torque limiting strategies and resulting in customer complaints.

[0003] Among the many causes of catalytic converter efficiency decline, HC poisoning is a common failure mode. In diesel engines, HC is generated due to the thin air and low combustion temperature at the fuel injection edge, low load, and idling. Additionally, in areas with low air-fuel ratios under high loads, incomplete combustion of fuel also produces significant HC emissions. When HC emissions from the exhaust pass through the catalytic converter, they are adsorbed onto its surface, preventing the catalyst from reacting with pollutants in the exhaust—a condition commonly known as "poisoning." However, HC poisoning is reversible. With proper control strategies, HC can be removed from the catalytic converter, restoring its conversion efficiency, and reducing the triggering of torque limiting strategies, thus minimizing user complaints.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a control device and method for real-time prevention of HC poisoning in catalysts. Through a reasonable control strategy, it can not only remove HC from the catalyst and restore the conversion efficiency of the catalyst, but also reduce the triggering of torque limiting strategies and reduce user complaints.

[0006] To achieve the above objectives, the present invention provides a control device for real-time prevention of HC poisoning in the catalytic converter, including a T4 temperature sensor and a NOx sensor; the T4 temperature sensor is disposed at the junction of the exhaust device and the DOC+DPF; the NOx sensor is disposed at the junction of the exhaust device and the DOC+DPF.

[0007] In a preferred embodiment, it further includes SCR+ASC which is sequentially connected to DOC+DPF.

[0008] To achieve the above objectives, the present invention also provides a control method for real-time prevention of HC poisoning in the catalytic converter, which utilizes the control device described above. The control method includes: Step 1, passing the engine exhaust gas sequentially through a T4 temperature sensor, DOC, DPF, SCR, and ASC; Step 2, obtaining HC emissions under different operating conditions through steady-state bench testing and establishing a steady-state model of HC emissions; Step 3, determining the correction coefficient for HC during transient acceleration by combining the transient calibration of the bench test and the λ value obtained from the NOx sensor in the exhaust gas; Step 4, using catalytic converter characteristics and the current exhaust flow... Step 5: Determine the current HC conversion efficiency of the catalytic converter based on the quantity, exhaust temperature, oxygen concentration, and degradation coefficient; Step 6: Determine the HC accumulation amount at the minimum allowable efficiency limit of the catalytic converter conversion efficiency based on the characteristics of the catalytic converter and the emission route; Step 7: Adjust the engine injection parameters, timing, rail pressure, throttle, and post-injection quantity to ensure that the temperature sensed by the T4 temperature sensor of the catalytic converter is greater than 300°C; and Step 8: Evaluate the current catalytic converter conversion efficiency in real time based on the new engine operating conditions and calculate the current HC accumulation amount until the HC accumulation amount is less than the HC accumulation limit.

[0009] In a preferred embodiment, the control method further includes obtaining the cumulative HC emissions in the current catalyst through steps two and three.

[0010] In a preferred embodiment, the control method further includes: obtaining the current accumulated HC emissions in the catalyst through steps two and three, and the HC conversion efficiency obtained through step four, thereby obtaining the accumulated HC emissions inside the catalyst, and performing real-time integration and accumulation of the accumulated HC emissions in the catalyst to obtain the actual accumulated HC amount.

[0011] In a preferred embodiment, the control method further includes: comparing the actual HC accumulation with the HC accumulation obtained in step five; if the limit is exceeded, triggering the HC removal procedure.

[0012] In a preferred embodiment, the control method further includes: if the temperature sensed by the T4 temperature sensor is not greater than 300°C, then the loop is closed in real time until the T4 temperature reaches greater than 300°C.

[0013] Compared with the prior art, the control device and method for real-time avoidance of HC poisoning in catalytic converters of the present invention have the following beneficial effects: This solution combines the characteristics of emissions and catalytic converters to determine the boundary of HC poisoning; it compares the actual HC accumulation in the catalytic converter with the HC poisoning boundary to trigger the HC removal procedure; it proposes a method for HC removal by adjusting engine control parameters to increase exhaust temperature; it eliminates the impact of catalytic converter efficiency degradation, improves the accuracy of HC poisoning diagnosis, and simultaneously restores catalytic converter performance in a timely manner, improving exhaust gas conversion efficiency and reducing user complaints caused by torque limiting. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the equipment layout of a control device according to an embodiment of the present invention;

[0015] Figure 2 This is a schematic diagram of the control flow of a control method according to an embodiment of the present invention. Detailed Implementation

[0016] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0017] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0018] like Figure 1 As shown, a control device for real-time prevention of HC poisoning in a catalytic converter according to a preferred embodiment of the present invention includes a T4 temperature sensor and a NOx sensor; the T4 temperature sensor is disposed at the junction of the exhaust device and the DOC+DPF; the NOx sensor is disposed at the junction of the exhaust device and the DOC+DPF.

[0019] In some implementations, an SCR+ASC is also included, sequentially connected to the DOC+DPF. The exhaust gas from the diesel engine passes through the T4 temperature sensor, NOx sensor, and devices such as DOC, DPF, SCR, and ASC before being discharged.

[0020] like Figure 2As shown, a control method for real-time prevention of HC poisoning in a catalytic converter according to a preferred embodiment of the present invention utilizes the control device described above. The control method includes: Step 1, passing engine exhaust gas sequentially through a T4 temperature sensor, DOC, DPF, SCR, and ASC; Step 2, obtaining HC emissions under different operating conditions through bench steady-state tests and establishing a steady-state model of HC emissions; Step 3, determining the HC correction coefficient during transient acceleration by combining the bench transient calibration and the λ value obtained from the NOx sensor in the exhaust gas; Step 4, using catalytic converter characteristics and the current exhaust flow... Step 5: Determine the current HC conversion efficiency of the catalytic converter based on the quantity, exhaust temperature, oxygen concentration, and degradation coefficient; Step 6: Determine the HC accumulation amount at the minimum allowable efficiency limit of the catalytic converter conversion efficiency based on the characteristics of the catalytic converter and the emission route; Step 7: Adjust the engine injection parameters, timing, rail pressure, throttle, and post-injection quantity to ensure that the temperature sensed by the T4 temperature sensor of the catalytic converter is greater than 300°C; and Step 8: Evaluate the current catalytic converter conversion efficiency in real time based on the new engine operating conditions and calculate the current HC accumulation amount until the HC accumulation amount is less than the HC accumulation limit.

[0021] In some implementations, the control method further includes obtaining the cumulative HC emissions in the current catalyst through steps two and three.

[0022] In some embodiments, the control method further includes: obtaining the current accumulated HC emissions in the catalyst through steps two and three, and the HC conversion efficiency obtained through step four, thereby obtaining the accumulated HC emissions inside the catalyst, and performing real-time integration and accumulation of the accumulated HC emissions in the catalyst to obtain the actual accumulated HC amount.

[0023] In some implementations, the control method further includes: comparing the actual HC accumulation with the HC accumulation obtained in step five, and if the limit is exceeded, triggering the HC removal procedure.

[0024] In some implementations, the control method further includes: if the temperature sensed by the T4 temperature sensor is not greater than 300°C, then the loop is closed in real time until the T4 temperature reaches greater than 300°C.

[0025] In summary, the control device and method for real-time prevention of HC poisoning in catalytic converters of the present invention have the following advantages: This solution combines emission and catalytic converter characteristics to determine the boundary of HC poisoning; it compares the actual HC accumulation in the catalytic converter with the HC poisoning boundary to trigger the HC removal procedure; it proposes a method for HC removal by adjusting engine control parameters to increase exhaust temperature; it eliminates the impact of catalytic converter efficiency degradation, improves the accuracy of HC poisoning diagnosis, and simultaneously restores catalytic converter performance in a timely manner, improving exhaust gas conversion efficiency and reducing user complaints caused by torque limiting.

[0026] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A control method for real-time prevention of HC poisoning in a catalyst, wherein control is achieved through a control device for real-time prevention of HC poisoning in the catalyst, characterized in that, The control device includes: The T4 temperature sensor is located at the junction of the exhaust system and the DOC+DPF; and The NOx sensor is located at the junction of the exhaust system and the DOC+DPF. The control method includes: Step 1: The engine exhaust gas passes sequentially through the T4 temperature sensor, DOC, DPF, SCR, and ASC. Step 2: Obtain HC emissions under different operating conditions through bench steady-state tests and establish a steady-state model for HC emissions; Step 3: Combine the transient calibration of the test bench with the λ value obtained from the NOx sensor in the exhaust gas to determine the correction coefficient of HC during transient acceleration. Step 4: Determine the current HC conversion efficiency of the catalyst based on the catalyst characteristics and the current exhaust flow rate, exhaust temperature, oxygen concentration, and degradation coefficient. Step 5: Determine the cumulative HC amount at the minimum allowable efficiency limit of the catalyst conversion efficiency based on the characteristics of the catalyst and the emission route. Step six involves adjusting the engine's injection parameters—timing, rail pressure, throttle position, and post-injection quantity—to ensure that the temperature sensed by the catalytic converter's T4 temperature sensor exceeds 300°C; and Step 7: Based on the new engine's operating status, evaluate the current catalyst conversion efficiency in real time and calculate the current HC accumulation until the HC accumulation is less than the HC accumulation limit. If the temperature sensed by the T4 temperature sensor is not greater than 300℃, the loop will be closed in real time until the T4 temperature reaches greater than 300℃.

2. The control method for real-time avoidance of HC poisoning in the catalyst as described in claim 1, characterized in that, It also includes SCR+ASC, which is sequentially connected to DOC+DPF.

3. The control method for real-time avoidance of HC poisoning in the catalyst as described in claim 1, characterized in that, The control method further includes obtaining the cumulative HC emissions in the current catalyst through steps two and three.

4. The control method for real-time avoidance of HC poisoning in the catalyst as described in claim 1, characterized in that, The control method further includes: obtaining the current accumulated HC emissions in the catalyst through steps two and three, and the HC conversion efficiency obtained through step four, which can obtain the accumulated HC emissions inside the catalyst, and performing real-time integration and accumulation of the accumulated HC emissions in the catalyst to obtain the actual accumulated HC amount.

5. The control method for real-time avoidance of HC poisoning in the catalyst as described in claim 4, characterized in that, The control method further includes: comparing the actual accumulated HC amount with the accumulated HC amount obtained in step five; if the limit is exceeded, the HC removal procedure is triggered.

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