Engine aftertreatment system and heating control method and device therefor

Abstract

The application discloses an engine aftertreatment system and a heating control method and device thereof, and the method comprises the following steps: obtaining preset partition threshold values of at least two levels of thermal management measures; obtaining an engine coolant temperature and an intake air temperature of an SCR system at at least one node; determining a target thermal management measure according to the engine coolant temperature, the intake air temperature and the preset partition threshold values; and adjusting working parameters of a heating module, an intake air throttle valve, an exhaust throttle valve and cylinder after-injection fuel operation according to the target thermal management measure. The application matches different thermal management measures based on actual working conditions by setting hierarchical thermal management measures, and controls the heating module, the intake air throttle valve, the exhaust throttle valve and the cylinder after-injection fuel operation in a partitioned manner, so that the exhaust gas temperature is rapidly increased, and the emission, temperature raising rate and economy are considered.

Description

Technical Field

[0001] This invention relates to the field of engine exhaust aftertreatment control technology, and in particular to an engine aftertreatment system and its heating control method and device. Background Technology

[0002] Selectively Catalytic Reduction (SCR) systems inject urea solution into the exhaust gas with the aid of a catalyst, reducing nitrogen oxides (NOx) in the exhaust gas into nitrogen (N2) and water (H2O). As engine emission standards become more stringent, such as stricter NOx and nitrogen oxide (PN) emission standards and the addition of N2O emission standards, and with emission cycle testing increasingly focusing on whole-vehicle testing, improving SCR conversion efficiency is crucial to meeting these new emission requirements.

[0003] Because the activity of SCR catalysts varies at different temperatures, existing technologies typically incorporate electric heating devices in exhaust aftertreatment systems to improve their performance, especially during engine cold starts, at relatively low temperatures. These existing electric heating devices are usually located upstream of the oxidation catalyst or the selective catalytic reduction (SCR) unit, improving SCR catalytic performance through continuous or intermittent heating. However, this approach suffers from several problems: exhaust gas temperature is significantly affected by intake and exhaust gases; relying solely on heating devices to raise exhaust gas temperature is inefficient; the system's overall power consumption is high, resulting in poor economic efficiency. Furthermore, the heating requirements for exhaust gases vary under different operating conditions; both continuous and intermittent heating can lead to overheating, resulting in energy waste, or insufficient heating, leading to low SCR conversion efficiency. Summary of the Invention

[0004] This invention provides an engine aftertreatment system and its heating control method and device to solve the problems of low temperature adjustment accuracy and heating efficiency and high system power consumption of existing exhaust gas aftertreatment heating devices, and can quickly increase the exhaust gas temperature.

[0005] According to one aspect of the present invention, a heating control method for an engine aftertreatment system is provided, the engine aftertreatment system comprising: an intake throttle valve, an exhaust throttle valve, a heating module, and an SCR system, the heating control method comprising:

[0006] Obtain preset zoning thresholds for at least two levels of thermal management measures;

[0007] Obtain the engine coolant temperature and the intake air temperature of the SCR system at at least one node;

[0008] The target thermal management measures are determined based on the engine coolant temperature, the intake air temperature, and the preset zone threshold.

[0009] Adjust the operating parameters of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder fuel injection operation according to the target thermal management measures.

[0010] Optionally, adjusting the operating parameters of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder post-injection fuel operation according to the target thermal management measures includes: under the first target thermal management measures, controlling the heating module and the intake throttle valve to start and closing the in-cylinder post-injection fuel operation; determining the first heating cycle and the first heating duty cycle of the heating module according to the first target thermal management measures; wherein the first heating duty cycle is negatively correlated with the engine coolant temperature; and adjusting the opening of the intake throttle valve according to the engine operating parameters.

[0011] Optionally, adjusting the operating parameters of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder post-injection fuel operation according to the target thermal management measures includes: controlling the start-up of the heating module, the intake throttle valve, and the in-cylinder post-injection fuel operation under the second target thermal management measures; determining the second heating cycle and the second heating duty cycle of the heating module according to the second target thermal management measures; wherein the second heating duty cycle is negatively correlated with the engine coolant temperature; adjusting the opening of the intake throttle valve according to the engine operating parameters; and determining the fuel injection quantity of the in-cylinder post-injection fuel operation according to the first intake air temperature on the intake side of the SCR system at the oxidation catalytic converter; wherein the fuel injection quantity is positively correlated with the first intake air temperature.

[0012] Optionally, adjusting the operating parameters of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder post-injection fuel operation according to the target thermal management measures includes: controlling the start-up of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder post-injection fuel operation under the third target thermal management measures; determining the third heating cycle and the third heating duty cycle of the heating module according to the third target thermal management measures; adjusting the opening of the intake throttle valve and the exhaust throttle valve according to the engine operating parameters; and determining the fuel injection quantity of the in-cylinder post-injection fuel operation according to the second intake air temperature on the intake side of the SCR system at the oxidation catalytic converter; wherein the fuel injection quantity is positively correlated with the second intake air temperature.

[0013] Optionally, adjusting the opening of the intake throttle valve and the exhaust throttle valve according to the engine's operating parameters includes: performing closed-loop pressure control on either the intake throttle valve or the exhaust throttle valve according to the engine's operating parameters.

[0014] Optionally, adjusting the operating parameters of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder fuel injection operation according to the target thermal management measures includes: under the fourth target thermal management measures, controlling the heating module and the in-cylinder fuel injection operation to close, and controlling the intake throttle valve and the exhaust throttle valve to start; adjusting the opening degree of the intake throttle valve and the exhaust throttle valve based on the engine intake air temperature and / or exhaust air temperature.

[0015] Optionally, obtaining the preset partition thresholds for at least two levels of thermal management measures includes: establishing at least one coolant temperature threshold based on the first emission requirement for cold nitrogen oxides; and establishing at least one intake air temperature threshold based on at least one of the conversion efficiency of the SCR system, engine fuel consumption, or the second emission requirement for nitrogen oxides.

[0016] Optionally, after initiating the in-cylinder post-injection fuel operation, the heating control method further includes: acquiring the cumulative fuel injection amount of the in-cylinder post-injection fuel operation; determining the oil dilution rate based on the cumulative fuel injection amount; and determining whether to trigger an oil change alarm based on the oil dilution rate.

[0017] According to another aspect of the present invention, a heating control device for an engine aftertreatment system is provided. The engine aftertreatment system includes: an intake throttle valve, an exhaust throttle valve, a heating module, and an SCR system. The heating control device includes: a threshold management module for acquiring preset partition thresholds for at least two levels of thermal management measures; a detection module for acquiring the engine coolant temperature and the intake air temperature of the SCR system at at least one node; a thermal management matching module for determining a target thermal management measure based on the engine coolant temperature, the intake air temperature, and the preset partition thresholds; and a thermal management execution module for adjusting the operating parameters of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder after-injection fuel operation according to the target thermal management measure.

[0018] According to another aspect of the present invention, an engine aftertreatment system is provided, comprising: an intake throttle valve, an exhaust throttle valve, a heating module, an SCR system, and the aforementioned heating control device; the heating control device is configured to: acquire preset partition thresholds for at least two levels of thermal management measures; acquire the engine coolant temperature and the intake air temperature of the SCR system at at least one node; determine a target thermal management measure based on the engine coolant temperature, the intake air temperature, and the preset partition thresholds; and adjust the operating parameters of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder after-injection fuel operation according to the target thermal management measure.

[0019] The technical solution of this invention establishes preset zoning thresholds for at least two levels of thermal management measures. After the engine is powered on, the engine coolant temperature and the intake air temperature of the SCR system at at least one node are obtained. Target thermal management measures are determined based on the engine coolant temperature, intake air temperature, and preset zoning thresholds. The operating parameters of the heating module, intake throttle valve, exhaust throttle valve, and in-cylinder after-injection fuel are adjusted according to the target thermal management measures. This solves the problems of low temperature regulation accuracy and heating efficiency, and high system power consumption of existing exhaust aftertreatment heating devices. By setting graded thermal management measures and matching different thermal management measures based on actual operating conditions, the heating module, intake throttle valve, exhaust throttle valve, and in-cylinder after-injection fuel are controlled in zones to rapidly increase exhaust gas temperature, balancing emissions, heating rate, and economy, and improving nitrogen oxide conversion efficiency. This results in higher nitrogen oxide emissions at the source and lower nitrogen oxide emissions from the tailpipe.

[0020] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of an engine exhaust aftertreatment system provided in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of an SCR system provided in an embodiment of the present invention;

[0024] Figure 3 This is a flowchart of a heating control method for an engine aftertreatment system provided in Embodiment 1 of the present invention;

[0025] Figure 4 A flowchart of a heating control method for an engine aftertreatment system under a first thermal management measure provided in Embodiment 1 of the present invention;

[0026] Figure 5 A flowchart of the heating control method for an engine aftertreatment system under the second thermal management measure provided in Embodiment 1 of the present invention;

[0027] Figure 6 A flowchart of the heating control method for an engine aftertreatment system under the third thermal management measure provided in Embodiment 1 of the present invention;

[0028] Figure 7 This is a schematic diagram of the working areas of an intake throttle valve and an exhaust throttle valve provided in Embodiment 1 of the present invention;

[0029] Figure 8 A flowchart of the heating control method for an engine aftertreatment system under the fourth thermal management measure provided in Embodiment 1 of the present invention;

[0030] Figure 9 A flowchart of another heating control method for an engine aftertreatment system provided in Embodiment 1 of the present invention;

[0031] Figure 10 This is a schematic diagram of the structure of a heating control device for an engine aftertreatment system provided in Embodiment 2 of the present invention. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0033] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0034] Figure 1 This is a schematic diagram of an engine exhaust aftertreatment system provided in an embodiment of the present invention. See also... Figure 1As shown, the engine exhaust aftertreatment system of this application includes: an intake throttle valve 201, an exhaust throttle valve 202, a heating module 203, and an SCR system 204. The intake throttle valve 201 is located between the intake pipe and the intake port of the engine E0. Adjusting the opening of the intake throttle valve 201 regulates the engine's intake volume and output power; for example, a smaller opening of the intake throttle valve 201 results in a smaller engine intake volume. The exhaust throttle valve 202 is located between the exhaust port of the engine E0 and the intake side of the heating module 203. Adjusting the opening of the exhaust throttle valve 202 regulates the engine's exhaust volume and exhaust pressure; for example, a smaller opening of the exhaust throttle valve 202 results in a smaller engine exhaust volume. The exhaust side of the heating module 203 is connected to the intake side of the SCR system 204, and the exhaust side of the SCR system 204 is connected to the exhaust pipe. The heating module 203 of this application can be an electrically heated exhaust pipe with built-in heating elements. The diameter of the electrically heated exhaust pipe is approximately the same as the diameter of the exhaust pipe. The heating module 203 is heated by an external 24V power supply to increase the temperature of the exhaust gas.

[0035] The SCR system described in this application can be a single SCR system or a dual SCR system. Figure 2 This is a schematic diagram of an SCR system provided in an embodiment of the present invention. See also... Figure 2 As shown, taking a dual SCR system as an example, the dual SCR system includes: a ccSCR assembly (i.e., a tightly coupled SCR assembly) 2041, an oxidation catalytic converter DOC (diesel oxide catalyst) 2042, a particulate filter DPF (diesel particulate filter) 2043, and a post-SCR assembly 2044 connected in sequence. The ccSCR assembly 2041 includes a close-coupled SCR and an ammonia slip catalyst (ASC). The rear-mounted SCR assembly 2044 includes an SCR and an ammonia slip catalyst (ASC). The SCR is used to inject urea before the SCR to reduce nitrogen oxides in the exhaust gas. The SCR is located far from the turbine. The ammonia slip catalyst (ASC) is used to oxidize excess ammonia. The oxidation catalytic converter (DOC) is installed before the DPF to convert NO in the exhaust gas into NO2, while increasing the exhaust gas temperature and assisting the normal operation of the DPF and SCR. The particulate filter (DPF) is used to capture particulate matter in the exhaust gas. When the mass of captured particulate matter reaches a certain level, passive or active regeneration is required to restore the DPF's ability to capture particulate matter.

[0036] Combination Figure 1 and Figure 2As shown, this application provides a heating control method for an engine aftertreatment system with an electric heating device. This method rapidly increases the exhaust gas temperature by optimizing thermal management measures, solving the problems of low temperature regulation accuracy and heating efficiency, and high system power consumption of existing exhaust aftertreatment heating devices, and can meet the requirements of China VII emission regulations. It should be understood that the heating control method provided in this application can be applied to single SCR system or dual SCR system application scenarios.

[0037] Example 1

[0038] Figure 3 A flowchart of a heating control method for an engine aftertreatment system provided in Embodiment 1 of the present invention is shown below. Figure 1 and Figure 2 As shown, the engine's exhaust aftertreatment system can be an SCR system, without an EGR system. This method can be executed by an engine aftertreatment system heating control device, which can be implemented in hardware and / or software and can be configured within the engine exhaust aftertreatment system.

[0039] See Figures 1 to 3 As shown, the heating control method for the engine aftertreatment system of this application specifically includes the following steps:

[0040] S1: Obtain the preset partition thresholds for at least two levels of thermal management measures.

[0041] Thermal management measures refer to methods used to regulate exhaust gas temperature. In this embodiment, the thermal management measures are implemented based on at least one of the following: intake throttle valve 201, exhaust throttle valve 202, and heating module 203.

[0042] The preset zone threshold represents a critical threshold used to distinguish the intervals where different thermal management measures are located. In this embodiment, the preset zone threshold includes, but is not limited to, at least one of: coolant temperature threshold or intake air temperature threshold.

[0043] S2: Obtain the engine coolant temperature and the intake air temperature of the SCR system at at least one node.

[0044] The engine coolant temperature is the engine water temperature collected by the engine ECU.

[0045] In this embodiment, see Figure 2 As shown, taking a dual SCR system as an example, temperature sensors can be installed on the intake side of the ccSCR assembly 2041, the intake side of the oxidation catalytic converter DOC, the intake side of the particulate filter DPF, and the intake side of the rear SCR assembly 2044 to collect the intake temperature of the corresponding nodes.

[0046] S3: Determine the target thermal management measures based on engine coolant temperature, intake air temperature, and preset zone thresholds.

[0047] The target thermal management measure is any thermal management measure determined based on the matching results of engine coolant temperature, intake air temperature and preset zone thresholds.

[0048] In some embodiments, in a single SCR system, thermal management measures are matched based on the engine coolant temperature and the intake air temperature on the SCR intake side. In other embodiments, in a dual SCR system, thermal management measures are matched based on the engine coolant temperature and the intake air temperature on the intake side of the rear-mounted SCR assembly 2044.

[0049] Specifically, taking the preset partition thresholds, including coolant temperature threshold and intake air temperature threshold, as an example, the engine coolant temperature is compared with the coolant temperature threshold, and the intake air temperature is compared with the intake air temperature threshold. Based on the comparison results, the parameter range corresponding to the current engine coolant temperature and intake air temperature is determined, and the thermal management measures corresponding to the parameter range are determined as the target thermal management measures.

[0050] S4: Adjust the operating parameters of the heating module, intake throttle valve, exhaust throttle valve, and in-cylinder fuel injection operation according to the target thermal management measures.

[0051] The operating parameters include, but are not limited to, at least one of the following: heating cycle, heating power or heating duty cycle of the heating module, opening degree of the intake throttle valve, opening degree of the exhaust throttle valve, and injection quantity of in-cylinder post-injection fuel operation.

[0052] In this embodiment, the operating parameters of the heating module, intake throttle valve, exhaust throttle valve, and in-cylinder post-injection fuel operation can be set to different values ​​under different thermal management measures, and their specific values ​​are not limited. This embodiment can establish operating parameters under different thermal management measures through calibration and store the corresponding operating parameters in the engine ECU. The engine ECU controls the operation of the heating module, intake throttle valve, exhaust throttle valve, and in-cylinder post-injection fuel operation according to the actual matched target thermal management measures.

[0053] For example, taking a preset partition threshold including two coolant temperature thresholds (e.g., the first coolant temperature threshold is 50°C and the second coolant temperature threshold is 70°C) and two intake air temperature thresholds (e.g., the first intake air temperature threshold is 200°C and the second intake air temperature threshold is 250°C) as an example, the first coolant temperature threshold, the second coolant temperature threshold, the first intake air temperature threshold, and the second intake air temperature threshold are respectively used as critical thresholds for different thermal management measures: if the engine coolant temperature is lower than the first coolant temperature threshold (e.g., 50°C), then the first thermal management measure is matched, which is the thermal management measure for the initial stage of cold start; if the engine coolant temperature is greater than or equal to the first coolant temperature threshold (e.g., 50°C) and less than the second coolant temperature threshold (e.g., 70°C), then the second thermal management measure is matched. The second thermal management measure is for a specific period of cold start operation, where the aftertreatment system is in the cold nitrogen oxide emission stage. If the engine coolant temperature is greater than or equal to the second coolant temperature threshold (e.g., 70°C) and the intake air temperature is less than the first intake air temperature threshold (e.g., 200°C), then the third thermal management measure is applied. If the engine coolant temperature is greater than or equal to the second coolant temperature threshold (e.g., 70°C), and the intake air temperature is greater than or equal to the first intake air temperature threshold (e.g., 200°C) but less than the second intake air temperature threshold (e.g., 250°C), then the fourth thermal management measure is applied. If the engine coolant temperature is greater than or equal to the second coolant temperature threshold (e.g., 70°C) and the intake air temperature is greater than or equal to the second intake air temperature threshold (e.g., 250°C), then the thermal management control strategy is terminated. Under different thermal management measures, as the intake air temperature and engine coolant temperature increase, the heating power of the heating device gradually decreases. By establishing graded thermal management measures and matching different thermal management measures according to actual working conditions, the operation of heating modules, intake throttle valves, exhaust throttle valves and in-cylinder post-injection fuel is controlled in zones to quickly increase exhaust gas temperature, taking into account emissions, heating rate and economy, and improving nitrogen oxide conversion efficiency, thereby achieving higher nitrogen oxide emissions in the primary pipe and lower nitrogen oxide emissions in the tailpipe.

[0054] In some embodiments, obtaining preset zoning thresholds for at least two levels of thermal management measures includes: establishing at least one coolant temperature threshold based on a first emission requirement for cold-state nitrogen oxides; and establishing at least one intake air temperature threshold based on at least one of the following: the conversion efficiency of the SCR system, engine fuel consumption, or a second emission requirement for nitrogen oxides. The first emission requirement for cold-state nitrogen oxides refers to the nitrogen oxide emission regulatory requirements during the engine's cold start phase in an emission cycle test. The second emission requirement for nitrogen oxides refers to the emission regulatory requirements for tailpipe nitrogen oxides under low-temperature engine operating conditions. Typically, the first emission requirement, the conversion efficiency of the SCR system, fuel consumption, and the second emission requirement for nitrogen oxides can be values ​​established based on China VII emission regulations, and their specific values ​​are not limited. In this embodiment, the intake air temperature threshold is greater than the coolant temperature threshold. Based on emission regulations, different thermal management measures are configured with interval thresholds. The electric heating device, in-cylinder after-injection fuel, intake throttle valve and exhaust throttle valve are controlled in intervals under different operating conditions to improve the adaptability of the aftertreatment system to different operating conditions. It can quickly increase the exhaust gas temperature. As the aftertreatment temperature continues to rise, fuel injection is added to accelerate the temperature rise rate on the one hand, and reduce the total power consumption of the system on the other hand, thereby improving the exhaust gas heating efficiency.

[0055] Figure 4 This is a flowchart illustrating a heating control method for an engine aftertreatment system under a first thermal management measure provided in Embodiment 1 of the present invention. In this embodiment, the first thermal management measure is a thermal management measure for the initial stage of cold start.

[0056] See Figure 4 As shown, the heating control method specifically includes the following steps:

[0057] S401: Obtain the preset partition thresholds for at least two levels of thermal management measures.

[0058] S402: Obtain the engine coolant temperature and the intake air temperature of the SCR system at at least one node.

[0059] S403: Determine target thermal management measures based on engine coolant temperature, intake air temperature, and preset zone thresholds.

[0060] S404: Under the first target thermal management measures, control the heating module and intake throttle valve to start, and shut down the in-cylinder fuel injection operation.

[0061] Among them, the first objective thermal management measure is the thermal management measure in the initial stage of cold start (i.e., the first type of thermal management measure).

[0062] S405: Determine the first heating cycle and the first heating duty cycle of the heating module based on the first target thermal management measures.

[0063] In this embodiment, the first heating duty cycle is negatively correlated with the engine coolant temperature; that is, the higher the engine coolant temperature, the lower the second heating duty cycle. For example, the first heating duty cycle can be any value greater than or equal to 80% and less than or equal to 90%.

[0064] In some embodiments, the first heating cycle may be negatively correlated with the engine coolant temperature; that is, the higher the engine coolant temperature, the shorter the first heating cycle. In other embodiments, the first heating cycle may be set to a fixed value. For example, the first heating cycle may be set to 60 seconds.

[0065] S406: Adjusts the opening of the intake throttle valve according to the engine's operating parameters.

[0066] In this embodiment, the engine's operating parameters include, but are not limited to, engine speed and output torque. The intake throttle valve opening is determined based on the engine speed and torque to ensure that the engine output power remains constant.

[0067] Specifically, the preset partition thresholds in this embodiment include at least a first coolant temperature threshold (e.g., 50°C). When the engine coolant temperature is lower than the first coolant temperature threshold (e.g., 50°C), the engine ECU controls the heating module to start heating, driving the heating module to heat the exhaust gas with a first heating cycle (e.g., 60 seconds) and a first heating duty cycle (e.g., 80%). The first heating duty cycle operates at a higher value. Simultaneously, the intake throttle valve is opened to reduce the intake air volume. In the initial stage of cold start, the combination of high-power heating and reduced intake air volume helps to quickly increase the aftertreatment temperature and improve the exhaust gas heating efficiency.

[0068] Figure 5 This is a flowchart of a heating control method for an engine aftertreatment system under a second thermal management measure provided in Embodiment 1 of the present invention. In this embodiment, the second thermal management measure is a thermal management measure for a specific period of cold start operation, during which the aftertreatment system is in a cold nitrogen oxide emission stage.

[0069] See Figure 5 As shown, the heating control method specifically includes the following steps:

[0070] S501: Obtain the preset partition thresholds for at least two levels of thermal management measures.

[0071] S502: Obtain the engine coolant temperature and the intake air temperature of the SCR system at at least one node.

[0072] S503: Determine target thermal management measures based on engine coolant temperature, intake air temperature, and preset zone thresholds.

[0073] S504: Under the second target thermal management measures, control the start-up of the heating module, intake throttle valve and in-cylinder post-injection fuel operation.

[0074] Among them, the second target thermal management measure is a thermal management measure that is implemented during a specific period of cold start operation and when the after-treatment system is in the cold nitrogen oxide emission stage (i.e., the second type of thermal management measure).

[0075] S505: Determine the second heating cycle and second heating duty cycle of the heating module based on the second target thermal management measures.

[0076] In this embodiment, the second heating duty cycle is negatively correlated with the engine coolant temperature; that is, the higher the engine coolant temperature, the lower the second heating duty cycle. For example, the second heating duty cycle can be any value greater than 40% and less than or equal to 60%.

[0077] In some embodiments, the second heating cycle may be negatively correlated with the engine coolant temperature; that is, the higher the engine coolant temperature, the shorter the second heating cycle. In other embodiments, the second heating cycle may be set to a fixed value. For example, the second heating cycle may be set to 60 seconds.

[0078] S506: Adjusts the opening of the intake throttle valve according to the engine's operating parameters.

[0079] In this embodiment, the engine's operating parameters include, but are not limited to, engine speed and output torque. The intake throttle valve opening is determined based on the engine speed and torque to ensure that the engine output power remains constant.

[0080] S507: The injection quantity for in-cylinder post-injection fuel operation is determined based on the first intake air temperature on the intake side of the SCR system at the oxidation catalytic converter. The injection quantity is positively correlated with the first intake air temperature.

[0081] In this embodiment, the amount of fuel injected for in-cylinder post-injection fuel operation is determined based on the first intake air temperature on the intake side of the DOC (Digital Oxidation Catalytic Converter). When the first intake air temperature is low, a small amount of fuel is added to prevent unburned fuel from failing to ignite in the DOC and accumulating in the DPF, leading to abnormal temperature rise. When the first intake air temperature is high, the amount of fuel injected can be increased to quickly raise the temperature.

[0082] Specifically, the preset partition thresholds in this embodiment include at least a first coolant temperature threshold (e.g., 50°C) and a second coolant temperature threshold (e.g., 70°C). When the engine coolant temperature is higher than the first coolant temperature threshold (e.g., 50°C) but lower than the second coolant temperature threshold (e.g., 70°C), the engine ECU controls the heating module to start, driving the heating module to heat the exhaust gas with a second heating cycle (e.g., 60 seconds) and a second heating duty cycle (e.g., any value greater than 40% and less than or equal to 60%), rapidly increasing the aftertreatment temperature. Simultaneously, heating power is increased through in-cylinder fuel injection. After the intake air temperature and engine coolant temperature rise, the heating power of the heating module is appropriately reduced, cooperating with the intake throttle valve to reduce the intake air volume. At the same time, by introducing electric heating to assist in-cylinder fuel injection, both the temperature rise rate and system power economy are considered.

[0083] Figure 6 This is a flowchart illustrating a heating control method for an engine aftertreatment system under a third thermal management measure provided in Embodiment 1 of the present invention. In this embodiment, the third thermal management measure is a thermal management measure for the aftertreatment system operating in a low NOx conversion efficiency stage. Typically, low NOx conversion efficiency means that the NOx conversion efficiency is less than 90%.

[0084] See Figure 6 As shown, the heating control method specifically includes the following steps:

[0085] S601: Obtain the preset partition thresholds for at least two levels of thermal management measures.

[0086] S602: Obtain engine coolant temperature and intake air temperature of the SCR system at at least one node.

[0087] S603: Determine target thermal management measures based on engine coolant temperature, intake air temperature, and preset zone thresholds.

[0088] S604: Under the third target thermal management measures, control the start-up of the heating module, intake throttle valve, exhaust throttle valve and in-cylinder after-injection fuel operation.

[0089] Among them, the third target thermal management measure is the thermal management measure for the post-treatment system when it is operating in the stage of low nitrogen oxide conversion efficiency (i.e., the third type of thermal management measure).

[0090] S605: Determine the third heating cycle and the third heating duty cycle of the heating module based on the third target thermal management measures.

[0091] In this embodiment, the third heating duty cycle is relatively low. For example, the third heating duty cycle can be set to 40%. The third heating cycle can be set to a fixed value (e.g., 60 seconds).

[0092] S606: Adjusts the opening of the intake and exhaust throttle valves according to the engine's operating parameters.

[0093] Optionally, the opening degree of the intake throttle valve and the exhaust throttle valve can be adjusted according to the engine's operating parameters, including: performing closed-loop pressure control on either the intake throttle valve or the exhaust throttle valve according to the engine's operating parameters. In this embodiment, the engine's operating parameters include, but are not limited to, engine speed and engine output torque. The opening degree of the intake throttle valve is determined based on the engine speed and torque, and the opening degree of the exhaust throttle valve is also determined based on the engine speed and torque. Under different operating conditions, the adjustment targets of the intake throttle valve and the exhaust throttle valve are different.

[0094] Figure 7 This is a schematic diagram of the working areas of an intake throttle valve and an exhaust throttle valve according to Embodiment 1 of the present invention. See also... Figure 7 As shown, in region I, the engine speed is relatively low and the torque is relatively small. At this time, the intake pressure is controlled in a closed loop by the intake throttle valve to maintain the engine intake pressure at a constant or approximately constant level. In region II, the engine speed and torque are relatively high. The exhaust pressure is controlled in a closed loop by the exhaust throttle valve to maintain the engine exhaust pressure at a constant or approximately constant level.

[0095] S607: The injection quantity for in-cylinder post-injection fuel operation is determined based on the second intake air temperature on the intake side of the SCR system's oxidation catalytic converter. The injection quantity is positively correlated with the second intake air temperature.

[0096] In this embodiment, the amount of fuel injected for in-cylinder post-injection fuel operation is determined based on the second intake temperature on the intake side of the oxidation catalytic converter (DOC). When the second intake temperature is low, a small amount of fuel is added to prevent unburned fuel from failing to ignite in the DOC and accumulating in the DPF, leading to abnormal temperature rise. When the second intake temperature is high, the amount of fuel injected can be increased to quickly raise the temperature of the subsequent SCR stage.

[0097] Specifically, the preset partition thresholds in this embodiment include at least a second coolant temperature threshold (e.g., 70°C) and a first intake air temperature threshold (e.g., 200°C). When the engine coolant temperature is higher than the second coolant temperature threshold (e.g., 70°C) and the intake air temperature on the SCR intake side is lower than the first intake air temperature threshold (e.g., 200°C), the engine ECU drives the heating module to continuously heat with a third heating cycle (e.g., 60 seconds) and a third heating duty cycle (e.g., 40%) to rapidly increase the aftertreatment temperature. At the same time, the in-cylinder post-injection fuel operation is started to increase the heating power and rapidly increase the temperature of the subsequent SCR. Simultaneously, the engine ECU controls the opening of the intake throttle valve and the exhaust throttle valve, determines and adjusts the opening of the intake throttle valve according to the engine speed and torque, and adjusts the opening of the exhaust throttle valve according to the engine speed and torque. Under the condition of low engine speed and low torque, the intake pressure of the intake throttle valve is controlled in a closed loop; when the engine speed and torque are relatively high, the exhaust pressure of the exhaust throttle valve is controlled in a closed loop. In the low NOx conversion efficiency stage, the heating module, intake throttle valve, exhaust throttle valve and in-cylinder post-injection fuel operation work together to increase the heating power and quickly raise the temperature of the subsequent SCR, taking into account emissions, heating rate and economy.

[0098] Figure 8 This is a flowchart illustrating the heating control method for an engine aftertreatment system under the fourth thermal management measure provided in Embodiment 1 of the present invention. In this embodiment, the fourth thermal management measure is a thermal management measure for the aftertreatment system operating in a high NOx conversion efficiency stage. Typically, high NOx conversion efficiency means that the NOx conversion efficiency is greater than or equal to 95%.

[0099] See Figure 8 As shown, the heating control method specifically includes the following steps:

[0100] S801: Obtain the preset partition thresholds for at least two levels of thermal management measures.

[0101] S802: Obtain engine coolant temperature and intake air temperature of the SCR system at at least one node.

[0102] S803: Determine target thermal management measures based on engine coolant temperature, intake air temperature, and preset zone thresholds.

[0103] S804: Under the fourth target thermal management measures, control the heating module and the in-cylinder after-injection fuel operation to shut down, and control the intake throttle valve and exhaust throttle valve to start.

[0104] Among them, the fourth target thermal management measure is the thermal management measure for the post-treatment system when it is operating in the high nitrogen oxide conversion efficiency stage (i.e., the fourth type of thermal management measure).

[0105] S805: Adjusts the opening of the intake throttle valve and the exhaust throttle valve based on the engine intake air temperature and / or exhaust air temperature.

[0106] In this embodiment, the intake throttle valve is used to maintain idle temperature, and the exhaust throttle valve is used to rapidly increase temperature.

[0107] Specifically, the preset partition thresholds in this embodiment include at least: a second coolant temperature threshold (e.g., 70°C), a first intake air temperature threshold (e.g., 200°C), and a second intake air temperature threshold (e.g., 250°C). When the engine coolant temperature is higher than the second coolant temperature threshold (e.g., 70°C), and the intake air temperature on the SCR (or ccSCR) intake side is greater than the first intake air temperature threshold (e.g., 200°C) but less than the second intake air temperature threshold (e.g., 250°C), the engine ECU controls the heating module and in-cylinder after-injection fuel operation to shut down. Temperature regulation is achieved by adjusting the opening of the intake throttle valve and the exhaust throttle valve. The intake throttle valve achieves idle temperature maintenance, and the exhaust throttle valve achieves rapid temperature increase, avoiding energy waste caused by overheating of the heating module and improving system economy.

[0108] Optionally, the opening degree of the intake throttle valve and the exhaust throttle valve can be adjusted according to the engine's operating parameters, including: performing closed-loop pressure control on either the intake throttle valve or the exhaust throttle valve based on the engine's operating parameters. In this embodiment, the engine's operating parameters include, but are not limited to, engine speed and engine output torque. The opening degree of the intake throttle valve is determined based on the engine speed and torque, adjusting the intake air volume while...

[0109] In this embodiment, when the engine coolant temperature is higher than the second coolant temperature threshold (e.g., 70°C) and the intake air temperature on the intake side of the SCR (or ccSCR) is greater than the second intake air temperature threshold (e.g., 250°C), the thermal management control strategy is exited.

[0110] Figure 9 A flowchart of another heating control method for an engine aftertreatment system provided in Embodiment 1 of the present invention is shown below. Figure 9 As shown, the heating control method specifically includes:

[0111] S901: Obtain the preset partition thresholds for at least two levels of thermal management measures.

[0112] S902: Obtain engine coolant temperature and intake air temperature of the SCR system at at least one node.

[0113] S903: Determine target thermal management measures based on engine coolant temperature, intake air temperature, and preset zone thresholds.

[0114] S904: Adjust the operating parameters of the heating module, intake throttle valve, exhaust throttle valve, and in-cylinder post-injection fuel operation according to the target thermal management measures.

[0115] S905: After initiating in-cylinder post-injection fuel operation, obtain the cumulative amount of fuel injected during the in-cylinder post-injection fuel operation.

[0116] Among them, the cumulative injection amount represents the total amount of fuel injected from the start of the in-cylinder post-injection fuel operation to the sampling time.

[0117] S906: Determine the oil dilution rate based on the cumulative amount of oil injected.

[0118] The oil dilution rate is equal to the ratio between the cumulative amount of oil injected and the preset oil change mileage (e.g., 2000 kilometers).

[0119] S907: Determine whether to trigger an oil change warning based on the oil dilution ratio.

[0120] In this embodiment, a preset dilution rate threshold can be established within a single oil change mileage by calibration. The oil dilution rate can be compared with the preset dilution rate threshold, and the oil change alarm can be triggered based on the comparison result.

[0121] In this embodiment, the oil change warning can be displayed via the vehicle's dashboard or a remote terminal device (such as a mobile phone or computer). The specific form of the oil change warning is not limited.

[0122] Specifically, after the in-cylinder fuel injection operation is initiated, the amount of fuel injected into the engine cylinders is statistically calculated in real time to obtain the cumulative injection volume. Then, the cumulative injection volume is divided by a preset oil change mileage (e.g., 3000 km) to obtain the dilution rate. Within one oil change mileage, when the oil dilution rate exceeds the preset dilution rate threshold, an oil change alarm is triggered and sent to the vehicle's instrument panel or terminal equipment to remind the customer to change the oil. By statistically analyzing the injection volume and calculating the oil dilution rate in real time, the system promptly reminds customers to change the oil, preventing oil dilution from affecting engine operation and improving system reliability.

[0123] Example 2

[0124] Based on the same inventive concept, Embodiment 2 of the present invention provides a heating control device for an engine aftertreatment system, which can execute the heating control method for an engine aftertreatment system provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of executing the method.

[0125] Figure 10 This is a schematic diagram of the structure of a heating control device for an engine aftertreatment system provided in Embodiment 2 of the present invention. Figure 10As shown, the heating control device of the engine aftertreatment system includes: a threshold management module 101, a detection module 102, a thermal management matching module 103, and a thermal management execution module 104.

[0126] The threshold management module 101 is used to obtain preset partition thresholds for at least two levels of thermal management measures; the detection module 102 is used to obtain the engine coolant temperature and the intake air temperature of the SCR system at at least one node; the thermal management matching module 103 is used to determine the target thermal management measures based on the engine coolant temperature, intake air temperature and preset partition thresholds; and the thermal management execution module 104 is used to adjust the operating parameters of the heating module, intake throttle valve, exhaust throttle valve and in-cylinder after-injection fuel operation according to the target thermal management measures.

[0127] Optionally, the thermal management execution module 104 is configured to: control the heating module and intake throttle valve to start under the first target thermal management measures, and shut down the in-cylinder after-injection fuel operation; determine the first heating cycle and first heating duty cycle of the heating module according to the first target thermal management measures; wherein the first heating duty cycle is negatively correlated with the engine coolant temperature; and adjust the opening of the intake throttle valve according to the engine operating parameters.

[0128] Optionally, the thermal management execution module 104 is configured to: control the start-up of the heating module, intake throttle valve, and in-cylinder post-injection fuel operation under the second target thermal management measures; determine the second heating cycle and second heating duty cycle of the heating module according to the second target thermal management measures; wherein the second heating duty cycle is negatively correlated with the engine coolant temperature; adjust the opening of the intake throttle valve according to the engine operating parameters; and determine the fuel injection quantity for in-cylinder post-injection fuel operation according to the first intake air temperature on the intake side of the SCR system at the oxidation catalytic converter; wherein the fuel injection quantity is positively correlated with the first intake air temperature.

[0129] Optionally, the thermal management execution module 104 is configured to: control the start-up of the heating module, intake throttle valve, exhaust throttle valve, and in-cylinder post-injection fuel operation under the third target thermal management measures; determine the third heating cycle and third heating duty cycle of the heating module according to the third target thermal management measures; adjust the opening of the intake throttle valve and exhaust throttle valve according to the engine operating parameters; and determine the fuel injection quantity for in-cylinder post-injection fuel operation according to the second intake air temperature on the intake side of the SCR system at the oxidation catalytic converter; wherein the fuel injection quantity is positively correlated with the second intake air temperature.

[0130] Optionally, the thermal management execution module 104 is also configured to: under the third target thermal management measures, perform closed-loop pressure control on either the intake throttle valve or the exhaust throttle valve based on the engine's operating parameters.

[0131] Optionally, the thermal management execution module 104 is also configured to: control the heating module and the in-cylinder after-injection fuel operation to shut down under the fourth target thermal management measures, and control the intake throttle valve and the exhaust throttle valve to start; and adjust the opening of the intake throttle valve and the exhaust throttle valve based on the engine intake air temperature and / or exhaust air temperature.

[0132] Optionally, the threshold management module 101 is configured to: establish at least one coolant temperature threshold based on the first emission requirement of cold nitrogen oxides; and establish at least one intake air temperature threshold based on at least one of the conversion efficiency of the SCR system, fuel consumption, or the second emission requirement of nitrogen oxides.

[0133] In some embodiments, the engine aftertreatment system heating control device of this application further includes: an oil alarm module, used to acquire the cumulative amount of fuel injection during in-cylinder after-injection fuel operation, determine the oil dilution rate based on the cumulative amount of fuel injection, and determine whether to trigger an oil change alarm based on the oil dilution rate.

[0134] The engine aftertreatment system heating control device of this invention includes a threshold management module, a detection module, a thermal management matching module, and a thermal management execution module. The threshold management module establishes preset partition thresholds for at least two levels of thermal management measures. After the engine is powered on, the detection module acquires the engine coolant temperature and the intake air temperature of the SCR system at at least one node. The thermal management matching module determines the target thermal management measures based on the engine coolant temperature, intake air temperature, and preset partition thresholds. The thermal management execution module adjusts the operating parameters of the heating module, intake throttle valve, exhaust throttle valve, and in-cylinder fuel injection operation according to the target thermal management measures. This solves the problems of low temperature adjustment accuracy and heating efficiency, and high system power consumption of existing exhaust aftertreatment heating devices. By setting graded thermal management measures and matching different thermal management measures based on actual operating conditions, the heating module, intake throttle valve, exhaust throttle valve, and in-cylinder fuel injection operation are controlled in partitions to quickly increase the exhaust gas temperature, balancing emissions, heating rate, and economy, and improving nitrogen oxide conversion efficiency. This results in higher nitrogen oxide emissions at the source and lower nitrogen oxide emissions from the tailpipe.

[0135] Example 3

[0136] Based on the same inventive concept, this invention provides an engine aftertreatment system, including: an intake throttle valve, an exhaust throttle valve, a heating module, an SCR system, and a heating control device provided in the above embodiments. The heating control device in this embodiment is configured to: acquire preset zoning thresholds for at least two levels of thermal management measures; acquire the engine coolant temperature and the intake air temperature of the SCR system at at least one node; determine target thermal management measures based on the engine coolant temperature, intake air temperature, and preset zoning thresholds; and adjust the operating parameters of the heating module, intake throttle valve, exhaust throttle valve, and in-cylinder after-injection fuel operation according to the target thermal management measures.

[0137] The engine aftertreatment system provided in this embodiment of the invention includes the heating control device provided in the above embodiment, and has the corresponding functional modules and beneficial effects of the heating control device. The same parts will not be described again.

[0138] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0139] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. An engine aftertreatment system heating control method, the engine aftertreatment system comprising: The intake throttle valve, exhaust throttle valve, heating module, and SCR system are characterized in that the heating control method includes: Obtaining preset zoning thresholds for at least two levels of thermal management measures includes: establishing at least one coolant temperature threshold based on the first emission requirement for cold nitrogen oxides; and establishing at least one intake air temperature threshold based on at least one of the conversion efficiency, fuel consumption, or second emission requirement for nitrogen oxides of the SCR system; wherein the preset zoning thresholds represent critical thresholds used to distinguish the intervals in which different thermal management measures are located. Obtain the engine coolant temperature and the intake air temperature of the SCR system at at least one node; The target thermal management measures are determined based on the engine coolant temperature, the intake air temperature, and the preset zone threshold. Adjust the operating parameters of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder fuel injection operation according to the target thermal management measures.

2. The engine aftertreatment system heating control method of claim 1, wherein, The adjustment of the operating parameters of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder after-injection fuel operation according to the target thermal management measures includes: Under the first target thermal management measure, the heating module and the intake throttle valve are activated, and the in-cylinder fuel injection operation is shut off; The first heating cycle and the first heating duty cycle of the heating module are determined according to the first target thermal management measure; wherein, the first heating duty cycle is negatively correlated with the engine coolant temperature; The opening of the intake throttle valve is adjusted according to the engine's operating parameters.

3. The heating control method for an engine aftertreatment system according to claim 1, characterized in that, The adjustment of the operating parameters of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder after-injection fuel operation according to the target thermal management measures includes: Under the second target thermal management measures, the heating module, the intake throttle valve, and the in-cylinder post-injection fuel operation are controlled to start; The second heating cycle and the second heating duty cycle of the heating module are determined according to the second target thermal management measures; wherein, the second heating duty cycle is negatively correlated with the engine coolant temperature; The opening of the intake throttle valve is adjusted according to the engine's operating parameters; The injection quantity for the in-cylinder post-injection fuel operation is determined based on the first intake air temperature on the intake side of the SCR system at the oxidation catalytic converter; wherein the injection quantity is positively correlated with the first intake air temperature.

4. The heating control method for an engine aftertreatment system according to claim 1, characterized in that, The adjustment of the operating parameters of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder after-injection fuel operation according to the target thermal management measures includes: Under the third target thermal management measures, the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder after-injection fuel operation are started. The third heating cycle and the third heating duty cycle of the heating module are determined based on the third target thermal management measures. The opening degree of the intake throttle valve and the exhaust throttle valve is adjusted according to the engine's operating parameters; The injection quantity for the in-cylinder post-injection fuel operation is determined based on the second intake air temperature on the intake side of the SCR system at the oxidation catalytic converter; wherein the injection quantity is positively correlated with the second intake air temperature.

5. The heating control method for an engine aftertreatment system according to claim 4, characterized in that, Adjusting the opening of the intake throttle valve and the exhaust throttle valve according to the engine's operating parameters includes: Pressure closed-loop control is performed on either the intake throttle valve or the exhaust throttle valve based on the engine's operating parameters.

6. The heating control method for an engine aftertreatment system according to claim 1, characterized in that, The adjustment of the operating parameters of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder after-injection fuel operation according to the target thermal management measures includes: Under the fourth target thermal management measure, the heating module and the in-cylinder after-injection fuel operation are controlled to be shut off, and the intake throttle valve and the exhaust throttle valve are controlled to be activated; The opening degree of the intake throttle valve and the exhaust throttle valve is adjusted based on the engine intake air temperature and / or exhaust air temperature.

7. The heating control method for an engine aftertreatment system according to any one of claims 1 to 6, characterized in that, After in-cylinder fuel injection is initiated, the heating control method further includes: Obtain the cumulative amount of fuel injected during the in-cylinder post-injection fuel operation; The oil dilution rate is determined based on the cumulative amount of oil injected. Whether to trigger an oil change warning is determined based on the oil dilution ratio.

8. A heating control device for an engine aftertreatment system, the engine aftertreatment system comprising: The intake throttle valve, exhaust throttle valve, heating module, and SCR system are characterized in that the heating control device includes: The threshold management module is used to obtain preset partition thresholds for at least two levels of thermal management measures; the preset partition thresholds represent critical thresholds used to distinguish the intervals where different thermal management measures are located. The detection module is used to acquire the engine coolant temperature and the intake air temperature of the SCR system at at least one node. A thermal management matching module is used to determine target thermal management measures based on the engine coolant temperature, the intake air temperature, and the preset zone threshold. A thermal management execution module is used to adjust the operating parameters of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder after-injection fuel operation according to the target thermal management measures. The threshold management module is configured to: establish at least one coolant temperature threshold based on the first emission requirement of cold nitrogen oxides; and establish at least one intake air temperature threshold based on at least one of the following: the conversion efficiency of the SCR system, fuel consumption, or the second emission requirement of nitrogen oxides.

9. An engine aftertreatment system, characterized in that, include: Intake throttle valve, exhaust throttle valve, heating module, SCR system, and heating control device as described in claim 8; The heating control device is configured to: acquire preset partition thresholds for at least two levels of thermal management measures; acquire engine coolant temperature and intake air temperature of the SCR system at at least one node; determine target thermal management measures based on the engine coolant temperature, the intake air temperature, and the preset partition thresholds; and adjust the operating parameters of the heating module, the intake throttle valve, the exhaust throttle valve, and the in-cylinder after-injection fuel operation based on the target thermal management measures.

Images