System and control method for rapidly increasing temperature of catalytic converter

Abstract

The application relates to the field of engine post-processing technology and discloses a system for rapidly increasing the temperature of a catalytic converter, which comprises an exhaust pipe, a supercharger, an exhaust connecting pipe, an exhaust bypass valve, an exhaust bypass pipe and a catalytic converter; the output end of the exhaust pipe is connected with the input end of the supercharger and the input end of the exhaust bypass valve respectively, the output end of the supercharger is connected with the input end of the exhaust connecting pipe, the output end of the exhaust bypass valve is connected with the input end of the exhaust bypass pipe, the output end of the exhaust connecting pipe is connected with the input end of the catalytic converter, and the output end of the exhaust bypass pipe is connected with the input end of the catalytic converter; the system can rapidly increase the temperature of the catalytic converter by adding the exhaust bypass valve at the exhaust pipe and directly draining the exhaust to the catalytic converter through the exhaust bypass pipe; in addition, the opening degree of the exhaust bypass valve can be automatically adjusted in real time by constructing graph structure data based on the running data of the vehicle and performing information fusion through a prediction model, so that the emission of nitrogen oxides in the exhaust can be reduced.

Description

Technical Field

[0001] This invention relates to the field of engine aftertreatment technology, and more specifically, to a system and control method for rapidly increasing the temperature of a catalyst. Background Technology

[0002] Because the nitrogen oxide content in diesel engine exhaust is high and does not meet relevant emission regulations, the current main solution is to add an SCR (Selective Catalytic Reduction) catalyst and a urea injection device to the diesel engine exhaust pipe. During the exhaust process, urea is injected through the urea injection device. Under high temperature, the urea hydrolyzes to produce ammonia. The nitrogen oxides in the exhaust gas react with the ammonia under the catalytic action of the SCR catalyst to convert into nitrogen, thereby reducing the emission of nitrogen oxides from diesel engines.

[0003] However, the performance of SCR catalysts is strongly correlated with temperature; the lower the temperature, the lower the SCR catalytic efficiency. At the beginning of the bench cold-state test cycle, the SCR catalyst is at room temperature. At this time, the engine load is low, and the operating conditions change drastically. The exhaust temperature at this stage is very low, not reaching the urea injection threshold. Even after the exhaust temperature reaches the urea injection threshold, the SCR catalyst temperature remains low, resulting in very low SCR catalytic efficiency and high nitrogen oxide emissions. During vehicle emissions testing, if low ambient temperatures or urban driving conditions are encountered, the same problem of low SCR catalyst temperature leading to high nitrogen oxide emissions will occur.

[0004] Currently, common methods to increase catalytic converter temperature include: worsening engine combustion through throttle body adjustments and fuel injection timing, or increasing post-injection of fuel to raise exhaust temperature and thus rapidly increase catalytic converter temperature. However, both worsening engine combustion and increasing post-injection of fuel lead to increased fuel consumption, which is detrimental to the vehicle's economic competitiveness. Summary of the Invention

[0005] This invention provides a system and control method for rapidly increasing the temperature of a catalyst, thereby solving the technical problems mentioned in the background section.

[0006] This invention provides a system for rapidly increasing the temperature of a catalytic converter, comprising: an exhaust pipe, a turbocharger, an exhaust pipe connector, an exhaust bypass valve, an exhaust bypass pipe, and a catalytic converter;

[0007] The output end of the exhaust pipe is connected to the input end of the turbocharger and the input end of the exhaust bypass valve, respectively. The output end of the turbocharger is connected to the input end of the exhaust pipe. The output end of the exhaust bypass valve is connected to the input end of the exhaust bypass pipe. The output end of the exhaust pipe is connected to the input end of the catalytic converter. The output end of the exhaust bypass pipe is connected to the input end of the catalytic converter.

[0008] A method for controlling a system to rapidly increase catalyst temperature includes the following steps:

[0009] Step S201: Monitor the engine power-on status in real time. If the engine needs to be powered on, proceed to step S202; otherwise, repeat step S201.

[0010] Step S202: Obtain the vehicle's operating data at the current time, including: catalytic converter temperature, vehicle speed, gear, engine speed, circulating oil volume, accelerator pedal pressure, brake pedal pressure, engine oil temperature, ambient temperature, and exhaust bypass valve opening.

[0011] Step S203: Determine whether the catalyst temperature is greater than or equal to the first preset temperature threshold. If the catalyst temperature is less than the first preset temperature threshold and the vehicle speed is greater than or equal to the first speed threshold or the engine speed is greater than or equal to the second speed threshold, proceed to step S204; otherwise, proceed to step S207.

[0012] Step S204: Construct graph structure data based on the vehicle's operating data at the current time, and input the graph structure data into the prediction model. The output value represents the opening adjustment value of the exhaust bypass valve.

[0013] Graph structure data includes: nodes, node initialization vectors, and edges between nodes; nodes include: the first node and attribute nodes;

[0014] The prediction model includes: a first hidden layer, a second hidden layer, and a fully connected layer; the first hidden layer takes graph structure data as input and outputs an update matrix, where a row vector of the update matrix represents the update vector of a node in the graph structure data; the second hidden layer is used to extract the update vector of the first node in the update matrix; the fully connected layer takes the update vector of the first node as input and outputs a value representing the opening adjustment value of the exhaust bypass valve.

[0015] Step S205: Adjust the opening of the exhaust bypass valve to the opening adjustment value of the exhaust bypass valve, and guide the exhaust that has not passed through the turbocharger to the catalytic converter through the exhaust bypass pipe;

[0016] Step S206: Determine whether the catalyst temperature is greater than or equal to the second preset temperature threshold. If the catalyst temperature is greater than or equal to the first preset temperature threshold, proceed to step S207; otherwise, repeat steps S202 to S206.

[0017] Step S207: Close the exhaust bypass valve.

[0018] Furthermore, by measuring the voltage value of the engine circuit, if the voltage value is greater than or equal to a preset voltage threshold, it is determined that the engine needs to be powered on. The preset voltage threshold is a user-defined parameter.

[0019] Furthermore, both the first preset temperature threshold and the second preset temperature threshold are custom parameters.

[0020] Furthermore, both the first speed threshold and the second speed threshold are custom parameters.

[0021] Furthermore, the first node establishes a data mapping with the exhaust bypass valve opening, and the attribute nodes include: catalyst temperature node establishing a data mapping with catalyst temperature, vehicle speed node establishing a data mapping with vehicle speed, gear node establishing a data mapping with gear, engine speed node establishing a data mapping with engine speed, circulating oil quantity node establishing a data mapping with circulating oil quantity, accelerator pedal pressure node establishing a data mapping with accelerator pedal pressure, brake pedal pressure node establishing a data mapping with brake pedal pressure, engine oil temperature node establishing a data mapping with engine oil temperature, and ambient temperature node establishing a data mapping with ambient temperature.

[0022] Edges are established between the first node and all attribute nodes;

[0023] The initial vectors for the first node and attribute nodes are obtained through eight-bit binary encoding.

[0024] Furthermore, the update vector of the i-th node The calculation formula is as follows:

[0025] Where 1≤i≤10, N i Let h represent the set of nodes that have an edge with the i-th node. i Let h represent the initial vector of the i-th node. j Let W1 represent the initial vector of the j-th node, W2 represent the first and second weight parameters respectively, and σ represent the sigmoid activation function.

[0026] Furthermore, a training dataset is constructed using a simulation platform, including the following steps:

[0027] Step S301: Obtain the operating data of multiple vehicles and input them into the simulation platform, and randomly generate the opening adjustment value of the exhaust bypass valve that meets the constraints.

[0028] The constraints include: the catalyst temperature is less than the first preset temperature threshold; the vehicle speed is greater than or equal to the first speed threshold; the engine speed is greater than or equal to the second speed threshold; and the opening adjustment value of the exhaust bypass valve is greater than or equal to 0 and less than or equal to 1.

[0029] Step S302: Adjust the opening of the exhaust bypass valve according to the opening adjustment value of the exhaust bypass valve, and record the time to reach the second preset temperature threshold and the fuel consumption value when the second preset temperature threshold is reached for each group.

[0030] Step S303: Select the operating data of the vehicle that takes the shortest time to reach the second preset temperature threshold or has the shortest fuel consumption value when reaching the second preset temperature threshold as training data for a training sample, and use the corresponding opening adjustment value as the sample label for the training sample.

[0031] Step S304: Repeat steps S301 to S303 to obtain a training dataset with M training samples, where M is a user-defined parameter.

[0032] The beneficial effects of this invention are as follows: By adding an exhaust bypass valve at the exhaust pipe, the exhaust gas of the engine bypasses the turbocharger and is directly diverted to the catalytic converter through the exhaust bypass pipe. At this time, the exhaust gas does not undergo heat energy conversion through the turbocharger, and the exhaust temperature is higher, which can quickly increase the temperature of the catalytic converter. In addition, based on the vehicle's operating data, a graph structure data is constructed, and information is fused through a predictive model, which can automatically adjust the opening of the exhaust bypass valve in real time, thereby reducing the emission of nitrogen oxides in the exhaust. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of a system for rapidly increasing the temperature of a catalyst according to the present invention;

[0034] Figure 2 This is a flowchart of a control method for a system to rapidly increase the temperature of a catalyst according to the present invention;

[0035] Figure 3 This is a flowchart of the present invention for constructing a training dataset through a simulation platform;

[0036] Figure 4 This is a diagram showing the results of emissions testing of vehicles using the WHTC cycle on a bench, according to the present invention.

[0037] In the diagram: exhaust pipe 101, turbocharger 102, exhaust pipe 103, exhaust bypass valve 104, exhaust bypass pipe 105, and catalytic converter 106. Detailed Implementation

[0038] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, features described in some examples may be combined in other examples.

[0039] It should be noted that, unless otherwise defined, the technical or scientific terms used in one or more embodiments of the present invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in one or more embodiments of the present invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0040] like Figures 1-4 As shown, a system for rapidly increasing the temperature of a catalytic converter includes: an exhaust pipe 101, a turbocharger 102, an exhaust pipe 103, an exhaust bypass valve 104, an exhaust bypass pipe 105, and a catalytic converter 106.

[0041] The output end of the exhaust pipe 101 is connected to the input end of the turbocharger 102 and the input end of the exhaust bypass valve 104, respectively. The output end of the turbocharger 102 is connected to the input end of the exhaust pipe 103. The output end of the exhaust bypass valve 104 is connected to the input end of the exhaust bypass pipe 105. The output end of the exhaust pipe 103 is connected to the input end of the catalytic converter 106. The output end of the exhaust bypass pipe 105 is connected to the input end of the catalytic converter 106.

[0042] It should be noted that in the traditional solution, the engine discharges exhaust gas from the exhaust pipe 101. After passing through the turbocharger 102, some of the heat energy of the exhaust gas is converted into the kinetic energy of the rotor in the turbocharger 102, which causes the exhaust temperature to drop by 50 to 200°C. Finally, the exhaust gas enters the catalytic converter 106 through the exhaust pipe 103 for catalytic action. However, at this time, the exhaust temperature is low and it is difficult to reach the threshold for urea injection.

[0043] Therefore, the present invention provides a system for rapidly increasing the temperature of the catalytic converter by adding an exhaust bypass valve 104 at the exhaust pipe 101. The exhaust gas of the engine does not pass through the turbocharger 102, but is directly guided to the catalytic converter 106 through the exhaust bypass pipe 105. At this time, the exhaust gas does not undergo heat energy conversion through the turbocharger 102, and the exhaust temperature is higher, which can rapidly increase the temperature of the catalytic converter.

[0044] like Figure 2 As shown, the present invention provides a control method for a system to rapidly increase the temperature of a catalyst, comprising the following steps:

[0045] Step S201: Monitor the engine power-on status in real time. If the engine needs to be powered on, proceed to step S202; otherwise, repeat step S201.

[0046] Step S202: Obtain the vehicle's operating data at the current time, including: catalytic converter temperature, vehicle speed, gear, engine speed, circulating oil volume, accelerator pedal pressure, brake pedal pressure, engine oil temperature, ambient temperature, and exhaust bypass valve opening.

[0047] Step S203: Determine whether the catalyst temperature is greater than or equal to the first preset temperature threshold. If the catalyst temperature is less than the first preset temperature threshold and the vehicle speed is greater than or equal to the first speed threshold or the engine speed is greater than or equal to the second speed threshold, proceed to step S204; otherwise, proceed to step S207.

[0048] Step S204: Construct graph structure data based on the vehicle's operating data at the current time, and input the graph structure data into the prediction model. The output value represents the opening adjustment value of the exhaust bypass valve.

[0049] Graph structure data includes: nodes, node initialization vectors, and edges between nodes;

[0050] The nodes include: the first node and attribute nodes;

[0051] The prediction model includes: a first hidden layer, a second hidden layer, and a fully connected layer;

[0052] The first hidden layer takes graph structure data as input and outputs an update matrix. Each row vector of the update matrix represents the update vector of a node in the graph structure data.

[0053] The second hidden layer is used to extract the update vector of the first node of the update matrix;

[0054] The fully connected layer takes the update vector of the first node as input and outputs a value representing the opening adjustment value of the exhaust bypass valve.

[0055] Step S205: Adjust the opening of the exhaust bypass valve to the opening adjustment value of the exhaust bypass valve, and guide the exhaust that has not passed through the turbocharger to the catalytic converter through the exhaust bypass pipe;

[0056] Step S206: Determine whether the catalyst temperature is greater than or equal to the second preset temperature threshold. If the catalyst temperature is greater than or equal to the first preset temperature threshold, proceed to step S207; otherwise, repeat steps S202 to S206.

[0057] Step S207: Close the exhaust bypass valve.

[0058] In one embodiment of the present invention, by measuring the voltage value of the engine circuit, if the voltage value is greater than or equal to a preset voltage threshold, it is determined that the engine needs to be powered on. The preset voltage threshold is a custom parameter, for example, the preset voltage threshold is set to 1 volt.

[0059] In one embodiment of the present invention, the catalytic converter temperature, engine oil temperature and ambient temperature are obtained by a temperature sensor, the vehicle speed is obtained by a vehicle speed sensor, the gear position is obtained by a gear position sensor, the engine speed is obtained by a crankshaft position sensor, the circulating oil volume is obtained by an oil volume sensor, the accelerator pedal pressure and brake pedal pressure are obtained by a pressure sensor, and the exhaust bypass valve opening is obtained by an engine control unit (ECU).

[0060] In one embodiment of the present invention, the first preset temperature threshold and the second preset temperature threshold are both custom parameters. Preferably, the first preset temperature threshold is set as the lower limit of the catalytic temperature of the catalyst, and the second preset temperature threshold is set as the upper limit of the catalytic temperature.

[0061] For example, if the lower limit of the catalytic temperature of an SCR catalyst is between 150 degrees Celsius and 200 degrees Celsius, then the first preset temperature threshold can be set to 200 degrees Celsius. If the upper limit of the catalytic temperature of an SCR catalyst is between 200 degrees Celsius and 400 degrees Celsius, then the second preset temperature threshold can be set to 300 degrees Celsius.

[0062] In one embodiment of the present invention, both the first speed threshold and the second speed threshold are custom parameters. Preferably, the first speed threshold is set to a vehicle speed of 20 km / h and the first speed threshold is set to the rated speed of the engine.

[0063] In one embodiment of the present invention, a data mapping is established between the first node and the exhaust bypass valve opening. The attribute nodes include: a data mapping between the catalyst temperature node and the catalyst temperature, a data mapping between the vehicle speed node and the vehicle speed, a data mapping between the gear node and the gear, a data mapping between the engine speed node and the engine speed, a data mapping between the circulating oil quantity node and the circulating oil quantity, a data mapping between the accelerator pedal pressure node and the accelerator pedal pressure, a data mapping between the brake pedal pressure node and the brake pedal pressure, a data mapping between the engine oil temperature node and the engine oil temperature, and a data mapping between the ambient temperature node and the ambient temperature.

[0064] Edges are established between the first node and all attribute nodes;

[0065] The initial vectors for the first node and attribute nodes are obtained through eight-bit binary encoding.

[0066] In one embodiment of the present invention, the update vector of the i-th node The calculation formula is as follows:

[0067] Where 1≤i≤10, N i Let h represent the set of nodes that have an edge with the i-th node. i Let h represent the initial vector of the i-th node. j Let W1 represent the initial vector of the j-th node, W2 represent the first and second weight parameters respectively, and σ represent the sigmoid activation function.

[0068] In one embodiment of the present invention, the vehicle's current operating data can also be input into the multilayer sensor, and the output value represents the opening adjustment value of the exhaust bypass valve.

[0069] like Figure 3 As shown, in one embodiment of the present invention, constructing a training dataset through a simulation platform includes the following steps:

[0070] Step S301: Obtain the operating data of multiple vehicles and input them into the simulation platform, and randomly generate the opening adjustment value of the exhaust bypass valve that meets the constraints.

[0071] The constraints include: the catalyst temperature is less than the first preset temperature threshold; the vehicle speed is greater than or equal to the first speed threshold; the engine speed is greater than or equal to the second speed threshold; and the opening adjustment value of the exhaust bypass valve is greater than or equal to 0 and less than or equal to 1.

[0072] Step S302: Adjust the opening of the exhaust bypass valve according to the opening adjustment value of the exhaust bypass valve, and record the time to reach the second preset temperature threshold and the fuel consumption value when the second preset temperature threshold is reached for each group.

[0073] Step S303: Select the operating data of the vehicle that takes the shortest time to reach the second preset temperature threshold or has the shortest fuel consumption value when reaching the second preset temperature threshold as training data for a training sample, and use the corresponding opening adjustment value as the sample label (real output value) of the training sample.

[0074] Step S304: Repeat steps S301 to S303 to obtain a training dataset with M training samples, where M is a custom parameter, for example, M is set to 100.

[0075] like Figure 4As shown, vehicle emissions tests were conducted using the WHTC (World Harmonized Cycle) test bench. The horizontal axis represents time in seconds, and the vertical axis represents catalyst temperature in degrees Celsius. Emission tests were conducted using a control method for rapidly increasing catalyst temperature provided by this patent, and a method without this patent. The control method for rapidly increasing catalyst temperature provided by this patent resulted in a significantly higher catalyst temperature during the initial time phase (0-800 seconds) compared to the method without this patent.

[0076] The embodiments of this example have been described above. However, this example is not limited to the specific implementation methods described above. The specific implementation methods described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms based on the guidance of this example, and all of them are within the protection scope of this example.

Claims

1. A control method for a system that rapidly increases the temperature of a catalyst, characterized in that, The system for rapidly increasing catalytic converter temperature includes: an exhaust pipe, a turbocharger, an exhaust manifold, an exhaust bypass valve, an exhaust bypass pipe, and a catalytic converter; the output end of the exhaust pipe is connected to the input end of the turbocharger and the input end of the exhaust bypass valve, the output end of the turbocharger is connected to the input end of the exhaust manifold, the output end of the exhaust bypass valve is connected to the input end of the exhaust bypass pipe, the output end of the exhaust manifold is connected to the input end of the catalytic converter, and the output end of the exhaust bypass pipe is connected to the input end of the catalytic converter. The control method includes the following steps: Step S201, real-time monitoring of the engine power-on status, and when it is determined that the engine needs to be powered on, proceed to step S202; otherwise, step S201 is executed repeatedly. Step S202: Obtain the vehicle's operating data at the current time, including: catalytic converter temperature, vehicle speed, gear, engine speed, circulating oil volume, accelerator pedal pressure, brake pedal pressure, engine oil temperature, ambient temperature, and exhaust bypass valve opening. Step S203: Determine whether the catalyst temperature is greater than or equal to the first preset temperature threshold. If the catalyst temperature is less than the first preset temperature threshold and the vehicle speed is greater than or equal to the first speed threshold or the engine speed is greater than or equal to the second speed threshold, proceed to step S204; otherwise, proceed to step S207. Step S204: Construct graph structure data based on the vehicle's operating data at the current time, and input the graph structure data into the prediction model. The output value represents the opening adjustment value of the exhaust bypass valve. Graph structure data includes: nodes, node initialization vectors, and edges between nodes; nodes include: the first node and attribute nodes; The prediction model includes: a first hidden layer, a second hidden layer, and a fully connected layer; the first hidden layer takes graph structure data as input and outputs an update matrix, where a row vector of the update matrix represents the update vector of a node in the graph structure data; the second hidden layer is used to extract the update vector of the first node in the update matrix; the fully connected layer takes the update vector of the first node as input and outputs a value representing the opening adjustment value of the exhaust bypass valve. Step S205: Adjust the opening of the exhaust bypass valve to the opening adjustment value of the exhaust bypass valve, and guide the exhaust that has not passed through the turbocharger to the catalytic converter through the exhaust bypass pipe; Step S206: Determine whether the catalyst temperature is greater than or equal to the second preset temperature threshold. If the catalyst temperature is greater than or equal to the first preset temperature threshold, proceed to step S207; otherwise, repeat steps S202 to S206. Step S207: Close the exhaust bypass valve.

2. The control method for a system for rapidly increasing catalyst temperature according to claim 1, characterized in that, By measuring the voltage value of the engine circuit, if the voltage value is greater than or equal to a preset voltage threshold, it is determined that the engine needs to be powered on. The preset voltage threshold is a user-defined parameter.

3. The control method for a system for rapidly increasing catalyst temperature according to claim 1, characterized in that, Both the first and second preset temperature thresholds are custom parameters.

4. The control method for a system for rapidly increasing catalyst temperature according to claim 1, characterized in that, Both the first and second speed thresholds are user-defined parameters.

5. The control method for a system for rapidly increasing catalyst temperature according to claim 1, characterized in that, The first node establishes a data mapping with the exhaust bypass valve opening. The attribute nodes include: catalyst temperature node and catalyst temperature data mapping, vehicle speed node and vehicle speed data mapping, gear node and gear data mapping, engine speed node and engine speed data mapping, circulating oil quantity node and circulating oil quantity data mapping, accelerator pedal pressure node and accelerator pedal pressure data mapping, brake pedal pressure node and brake pedal pressure data mapping, engine oil temperature node and engine oil temperature data mapping, and ambient temperature node and ambient temperature data mapping. Edges are established between the first node and all attribute nodes; The initial vectors for the first node and attribute nodes are obtained through eight-bit binary encoding.

6. The control method for a system for rapidly increasing catalyst temperature according to claim 1, characterized in that, The update vector of the i-th node The calculation formula is as follows: Where 1≤i≤10, Let represent the set of nodes that have an edge with the i-th node. Let represent the initial vector of the i-th node. Let represent the initial vector of the j-th node. and These represent the first weight parameter and the second weight parameter, respectively. This represents the sigmoid activation function.

7. The control method for a system for rapidly increasing catalyst temperature according to claim 1, characterized in that, The training dataset is constructed using a simulation platform, including the following steps: Step S301: Obtain the operating data of multiple vehicles and input them into the simulation platform, and randomly generate the opening adjustment value of the exhaust bypass valve that meets the constraints. The constraints include: the catalyst temperature is less than the first preset temperature threshold; the vehicle speed is greater than or equal to the first speed threshold; the engine speed is greater than or equal to the second speed threshold; and the opening adjustment value of the exhaust bypass valve is greater than or equal to 0 and less than or equal to 1. Step S302: Adjust the opening of the exhaust bypass valve according to the opening adjustment value of the exhaust bypass valve, and record the time to reach the second preset temperature threshold and the fuel consumption value when the second preset temperature threshold is reached for each group. Step S303: Select the operating data of the vehicle that takes the shortest time to reach the second preset temperature threshold or has the shortest fuel consumption value when reaching the second preset temperature threshold as training data for a training sample, and use the corresponding opening adjustment value as the sample label for the training sample. Step S304: Repeat steps S301 to S303 to obtain a training dataset with M training samples, where M is a user-defined parameter.

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