Engine EGR rate control method and system under transient working condition, vehicle and equipment

Abstract

The invention discloses an engine EGR rate control method and system under a transient working condition, a vehicle and equipment. The engine EGR rate control method under the transient working condition comprises the steps that whether an engine operates under the high EGR rate working condition or not is judged; if yes, the upstream fresh air flow of the air inlet system and the exhaust gas flow flowing through the EGR valve are recorded; delay time is obtained, and the delay time is the sum of the confluence time of the fresh air and the EGR waste gas and the time when the confluence gas enters the engine; according to the historical flow of upstream fresh air of the air inlet system before the rollback delay time and the historical flow of exhaust gas flowing through the EGR valve, the transient actual EGR rate of the engine at the current moment is obtained; according to the transient actual EGR rate of the engine, whether the engine exceeds the misfire boundary or not is judged; and if yes, the target EGR rate reducing strategy or the EGR disabling strategy is executed. By the adoption of the method and device, the actual EGR rate is obtained through the flow and delay of the fresh air and the EGR waste gas, the EGR reducing or disabling strategy is executed on the basis of the actual EGR rate, and therefore the fire risk caused by the too high EGR rate under the transient working condition is reduced.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and in particular to a method, system, vehicle, and equipment for controlling engine EGR rate under transient operating conditions. Background Technology

[0002] In low-pressure exhaust gas recirculation (EGR) technology, combustion exhaust gases must enter the engine intake manifold through the exhaust pipe downstream of the turbocharger, and then enter the engine cylinders through the intake manifold. Fresh air also needs to pass through a long intake manifold before entering the cylinders, thus both processes involve a certain transient response delay. This causes the EGR rate calculation model, designed for steady-state conditions, to become less accurate under transient conditions, leading to EGR rate deviations from control. Furthermore, when the engine is operating at a high EGR rate, if the engine speed or load decreases rapidly, the transient EGR rate can easily become too high, potentially causing misfires, resulting in reduced vehicle power, and in severe cases, burning out exhaust system components. Summary of the Invention

[0003] Therefore, it is necessary to address the aforementioned technical issues by obtaining the actual EGR rate through the flow rate and delay of fresh air and EGR exhaust gas, and then implement strategies to reduce or disable EGR based on this, thereby reducing the risk of fire caused by excessively high EGR rates during transient operating conditions.

[0004] Firstly, a method for controlling the engine EGR rate under transient operating conditions is provided, including: Determine if the engine is operating at a high EGR rate; If the engine is operating at a high EGR rate, record the current flow rate of fresh air upstream of the intake system and the flow rate of EGR exhaust gas flowing through the EGR valve. The delay time is obtained, wherein the delay time is the sum of the time required for fresh air and EGR exhaust gas to merge and the time required for the merged gas to enter the engine; The engine's transient actual EGR rate at the current moment is obtained by rewinding the historical fresh air flow rate upstream of the intake system from the current moment to the time before the delay, and the historical EGR exhaust gas flow rate through the EGR valve. Based on the actual transient EGR rate of the engine, determine whether the misfire boundary has been exceeded; If so, implement a strategy to reduce the target EGR rate or disable the EGR response strategy.

[0005] Furthermore, determining whether the engine is operating at a high EGR rate includes: Determine whether the actual transient EGR rate of the engine is greater than the EGR rate threshold, wherein the EGR rate threshold is pre-calibrated; If the actual transient EGR rate of the engine is greater than the EGR rate threshold, then the engine is determined to be operating under a high EGR rate condition.

[0006] Furthermore, obtaining the delay time includes: From the gas flow delay model, the time it takes for fresh air upstream of the intake system to flow to the point where it merges with the EGR exhaust gas, the time it takes for the EGR exhaust gas to flow to the point where it merges with the fresh air upstream of the intake system, and the time it takes for the mixture at the point of merging to flow to the engine are read. The delay time is obtained based on the time it takes for fresh air upstream of the intake system to flow to the point where it merges with the EGR exhaust gas, the time it takes for the EGR exhaust gas to flow to the point where it merges with the fresh air upstream of the intake system, and the time it takes for the mixture at the point of merging to flow to the engine.

[0007] Further, the step of obtaining the engine's transient actual EGR rate at the current moment based on the historical fresh air flow rate upstream of the intake system before the delay time from the current moment and the historical EGR exhaust gas flow rate through the EGR valve includes: The actual external EGR rate of the engine is obtained by rewinding the historical fresh air flow rate upstream of the intake system from the current moment to the time before the delay, and the historical EGR exhaust gas flow rate through the EGR valve. The internal EGR rate is read from the engine charging model based on the historical fresh air flow rate before the delay time from the current moment. The transient actual EGR rate of the engine at the current moment is obtained based on the actual external EGR rate and the internal EGR rate of the engine.

[0008] Further, determining whether the misfire boundary has been exceeded based on the engine's transient actual EGR rate includes: Determine whether the actual transient EGR rate of the engine exceeds the misfire threshold, wherein the misfire threshold is pre-calibrated; If so, then it is determined that the fire has exceeded the fire boundary.

[0009] Furthermore, the implementation of the strategy to reduce the target EGR rate includes: When it is determined that the fire boundary has been exceeded, the strategy to reduce the target EGR rate is executed, wherein executing the strategy to reduce the target EGR rate includes: Based on the actual transient EGR rate of the engine and the misfire level threshold, when a minor misfire is determined, a product coefficient is obtained, and the reduction in EGR rate is obtained based on the product coefficient. The target EGR rate is then reduced based on the reduction.

[0010] Furthermore, upon determining that a fire is a serious fire, an EGR (Extended Refrigerant Response) disabling strategy is implemented, the EGR disabling strategy including: Delay the ignition timing and close the EGR valve.

[0011] Secondly, a transient engine EGR rate control system is provided, including: The judgment module is used to determine whether the engine is operating under high EGR rate conditions; The confirmation module is used to record the flow rate of fresh air upstream of the intake system and the flow rate of EGR exhaust gas flowing through the EGR valve at the current moment when the engine is operating at a high EGR rate, and to obtain a delay time. The delay time is the sum of the time required for fresh air and EGR exhaust gas to merge and the time required for the merged gas to enter the engine. Based on the historical flow rate of fresh air upstream of the intake system and the historical flow rate of EGR exhaust gas flowing through the EGR valve before the current moment rewinds the delay time, the transient actual EGR rate of the engine at the current moment is obtained. The control module is used to determine whether the engine's transient actual EGR rate exceeds the misfire boundary, and if the misfire boundary is exceeded, to execute a strategy to reduce the target EGR rate or to disable the EGR response strategy.

[0012] Thirdly, a vehicle is provided, comprising: an engine EGR rate control system for transient operating conditions as described in the second aspect above.

[0013] Fourthly, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, it implements the steps of the engine EGR rate control method for transient operating conditions under the first aspect and any possible implementation of the first aspect.

[0014] In the embodiments of this application, it is first determined whether the engine is operating under a high EGR rate condition. If the engine is operating under a high EGR rate condition, the flow rate of fresh air upstream of the intake system and the flow rate of EGR exhaust gas flowing through the EGR valve at the current moment are recorded. Then, a delay time is obtained, where the delay time is the sum of the time required for fresh air and EGR exhaust gas to merge and the time required for the merged gas to enter the engine. Then, based on the historical flow rate of fresh air upstream of the intake system before the delay time from the current moment and the historical flow rate of EGR exhaust gas flowing through the EGR valve, the current moment's transient actual EGR rate of the engine is obtained. Next, based on the engine's transient actual EGR rate, it is determined whether the misfire boundary is exceeded. If so, a strategy to reduce the target EGR rate or a strategy to disable EGR is executed. Thus, the actual EGR rate is obtained by measuring the flow rate and delay of fresh air and EGR exhaust gas, and a strategy to reduce or disable EGR is executed based on this, thereby reducing the risk of misfire caused by excessively high transient EGR rates. Attached Figure Description

[0015] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 A flowchart of an engine EGR rate control method for transient operating conditions provided in an embodiment of this application; Figure 2 A schematic diagram illustrating the execution of the engine EGR rate control method under transient operating conditions provided in this application embodiment; Figure 3 A flowchart for calculating the actual EGR rate and actual fresh air intake volume under transient operating conditions provided in the embodiments of this application; Figure 4 A diagram illustrating the EGR disabling strategy provided in this application embodiment; Figure 5 A diagram illustrating the strategies for reducing the target EGR rate provided in this application embodiment; Figure 6 An overall architecture diagram provided for embodiments of this application; Figure 7 A structural block diagram of an engine EGR rate control system under transient operating conditions provided in this application embodiment; Figure 8 This is a structural block diagram of a computer device provided in an embodiment of this application. Detailed Implementation

[0016] The present application will now be described in further detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the application. Furthermore, it should be noted that, for ease of description, only the parts relevant to the application are shown in the accompanying drawings.

[0017] It should be noted that, unless otherwise specified, the embodiments and features of the embodiments in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] The following describes in detail, with reference to the accompanying drawings, an engine EGR rate control method, system, vehicle, and device under transient operating conditions according to embodiments of this application.

[0019] Figure 1 This is a flowchart of an engine EGR rate control method under transient operating conditions according to an embodiment of this application. Figure 1 As shown, and in combination Figure 2 The engine EGR rate control method under transient operating conditions according to the embodiments of this application includes the following steps: S101: Determines whether the engine is operating at a high EGR rate.

[0020] In one embodiment of this application, determining whether the engine is operating under a high EGR rate condition includes: determining whether the engine's transient actual EGR rate is greater than an EGR rate threshold, wherein the EGR rate threshold is pre-calibrated; if the engine's transient actual EGR rate is greater than the EGR rate threshold, then it is determined that the engine is operating under a high EGR rate condition.

[0021] S102: If the engine is operating at a high EGR rate, record the current flow rate of fresh air upstream of the intake system and the flow rate of EGR exhaust gas flowing through the EGR valve.

[0022] Among them, such as Figure 6 As shown, an air flow meter is installed upstream of the intake system. When fresh air flows through, the air flow meter measures and records the flow rate of the fresh air. An EGR valve is installed on the EGR system. When EGR exhaust gas flows through, the EGR differential pressure sensor measures and records the flow rate of the EGR exhaust gas.

[0023] S103: Obtain the delay time, wherein the delay time is the sum of the time required for fresh air and the EGR exhaust gas to merge and the time required for the merged gas to enter the engine.

[0024] In one embodiment of this application, obtaining the delay time includes: reading from a gas flow delay model the time it takes for fresh air upstream of the intake system to flow to the point where it merges with the EGR exhaust gas, the time it takes for the EGR exhaust gas to flow to the point where it merges with the fresh air upstream of the intake system, and the time it takes for the mixed gas at the point where it merges with the engine; and obtaining the delay time based on the time it takes for fresh air upstream of the intake system to flow to the point where it merges with the EGR exhaust gas, the time it takes for the EGR exhaust gas to flow to the point where it merges with the fresh air upstream of the intake system, and the time it takes for the mixed gas at the point where it merges with the engine.

[0025] Specifically, such as Figure 3 As shown, based on the gas flow delay model, the time it takes for the fresh air upstream of the intake system to flow to the point where it merges with the EGR exhaust gas, the time it takes for the EGR exhaust gas to flow to the point where it merges with the fresh air upstream of the intake system, and the time it takes for the mixed gas at the point of merging to flow to the engine can be obtained from the flow rate of the fresh air upstream of the intake system and the flow rate of the EGR exhaust gas flowing through the EGR valve, obtained in the above process. This information is stored in the engine control unit and is continuously updated over a certain period of time. The lengths of these three types of time periods are greater than the maximum values ​​of the corresponding time types under different engine operating conditions.

[0026] S104: Based on the historical fresh air flow rate upstream of the intake system before the delay time from the current moment and the historical EGR exhaust gas flow rate through the EGR valve, the actual transient EGR rate of the engine at the current moment is obtained.

[0027] In one embodiment of this application, obtaining the engine's transient actual EGR rate at the current moment based on the historical fresh air flow rate upstream of the intake system before the delay time from the current moment and the historical EGR exhaust gas flow rate through the EGR valve includes: obtaining the engine's actual external EGR rate based on the historical fresh air flow rate upstream of the intake system before the delay time from the current moment and the historical EGR exhaust gas flow rate through the EGR valve; reading the internal EGR rate from the engine charging model based on the historical fresh air flow rate before the delay time from the current moment; and obtaining the engine's transient actual EGR rate at the current moment based on the engine's actual external EGR rate and the internal EGR rate.

[0028] The engine's transient actual EGR rate is obtained by adding the engine's actual external EGR rate and internal EGR rate.

[0029] S105: Determine whether the misfire boundary has been exceeded based on the actual transient EGR rate of the engine.

[0030] In one embodiment of this application, determining whether the misfire boundary is exceeded based on the engine's transient actual EGR rate includes: determining whether the engine's transient actual EGR rate exceeds a misfire threshold, wherein the misfire threshold is pre-calibrated; if so, it is determined that the misfire boundary has been exceeded.

[0031] S106: If so, execute the strategy to reduce the target EGR rate or disable the EGR response strategy.

[0032] Specifically, it determines whether the difference between the engine's transient actual EGR rate and the misfire threshold is less than a preset limit. If so, it executes a strategy to reduce the target EGR rate; otherwise, it executes a strategy to disable EGR.

[0033] In one embodiment of this application, the execution of the target EGR rate reduction response strategy includes: executing the target EGR rate reduction response strategy when it is determined that the misfire boundary is exceeded, wherein executing the target EGR rate reduction response strategy includes: when it is determined to be a minor misfire based on the engine transient actual EGR rate and the misfire level threshold, obtaining a product coefficient, obtaining the reduction amount of EGR rate based on the product coefficient, and reducing the target EGR rate based on the reduction amount.

[0034] like Figure 5 As shown, after reducing the target EGR rate, it is determined whether the current transient actual EGR rate of the engine exceeds the misfire boundary. If it does not exceed the boundary, it means that the misfire has been controlled; if it does exceed the boundary, the above strategy is repeated.

[0035] In one embodiment of this application, when a serious misfire is determined, an EGR disable response strategy is implemented, which includes: delaying the ignition angle and closing the EGR valve.

[0036] like Figure 4 As shown, if EGR is suddenly disabled under high EGR rate conditions, the drastic change in control parameters can lead to transient engine knocking. Therefore, preventative measures such as retarding the ignition angle must be taken before disabling EGR to prevent transient knocking. The pre-retarded ignition angle for disabling EGR is obtained by multiplying three MAPs (Motor Range Maps) formed by pairwise combinations of three variables: pre-calibrated engine speed, load, and actual transient EGR rate. Next, the EGR valve is closed to cut off the EGR exhaust gas supply, thus disabling EGR. Then, when the pre-retarded ignition angle for disabling EGR = 0 and the average knock retraction angle > the average knock retraction angle limit, it indicates that the engine is operating in a relatively safe EGR-free condition, and the EGR system gradually resumes normal operation. Otherwise, it indicates that the engine is still operating in the transition process from a high EGR rate steady-state condition to an EGR-free steady-state condition, and the judgment is repeated. The average knock retraction angle limit is preset based on experimental experience.

[0037] According to the transient engine EGR rate control method of this application embodiment, the method first determines whether the engine is operating under a high EGR rate condition. If the engine is operating under a high EGR rate condition, the flow rate of fresh air upstream of the intake system and the flow rate of EGR exhaust gas flowing through the EGR valve at the current moment are recorded. Then, a delay time is obtained, wherein the delay time is the sum of the time required for fresh air and EGR exhaust gas to merge and the time required for the merged gas to enter the engine. Then, based on the historical flow rate of fresh air upstream of the intake system before the delay time from the current moment and the historical flow rate of EGR exhaust gas flowing through the EGR valve, the actual transient EGR rate of the engine at the current moment is obtained. Next, based on the actual transient EGR rate of the engine, it is determined whether the misfire boundary is exceeded. If so, a strategy to reduce the target EGR rate or a strategy to disable EGR is executed. Thus, the actual EGR rate is obtained by the flow rate and delay of fresh air and EGR exhaust gas, and the strategy to reduce or disable EGR is executed based on this, thereby reducing the risk of misfire caused by excessively high transient EGR rate.

[0038] Figure 7 This is a structural block diagram of an engine EGR rate control system under transient operating conditions according to an embodiment of this application. Figure 7 As shown, the engine EGR rate control system for transient operating conditions according to an embodiment of this application includes: a judgment module 710, a confirmation module 720, and a control module 730, wherein: The judgment module 710 is used to determine whether the engine is operating under a high EGR rate condition. The confirmation module 720 is used to record the flow rate of fresh air upstream of the intake system and the flow rate of EGR exhaust gas flowing through the EGR valve at the current moment when the engine is operating at a high EGR rate, and to obtain a delay time. The delay time is the sum of the time required for fresh air and EGR exhaust gas to merge and the time required for the merged gas to enter the engine. Based on the historical flow rate of fresh air upstream of the intake system and the historical flow rate of EGR exhaust gas flowing through the EGR valve before the current moment rewinds the delay time, the transient actual EGR rate of the engine at the current moment is obtained. The control module 730 is used to determine whether the misfire boundary is exceeded based on the actual transient EGR rate of the engine, and when the misfire boundary is exceeded, to execute a strategy to reduce the target EGR rate or to disable the EGR response strategy.

[0039] According to the transient engine EGR rate control system of this application embodiment, the system first determines whether the engine is operating under a high EGR rate condition. If the engine is operating under a high EGR rate condition, the system records the current flow rate of fresh air upstream of the intake system and the flow rate of EGR exhaust gas flowing through the EGR valve. Then, it obtains a delay time, which is the sum of the time required for fresh air and EGR exhaust gas to merge and the time required for the merged gas to enter the engine. Next, based on the historical flow rate of fresh air upstream of the intake system before the delay time from the current moment and the historical flow rate of EGR exhaust gas flowing through the EGR valve, the system obtains the current transient actual EGR rate of the engine. Then, based on the actual transient EGR rate of the engine, it determines whether the misfire boundary is exceeded. If so, it executes a strategy to reduce the target EGR rate or a strategy to disable EGR. Thus, by obtaining the actual EGR rate through the flow rates and delays of fresh air and EGR exhaust gas, and executing strategies to reduce or disable EGR based on this, the risk of misfire caused by excessively high transient EGR rates is reduced.

[0040] Specific limitations regarding the engine EGR rate control system for transient operating conditions can be found in the above-described limitations of the engine EGR rate control method for transient operating conditions, and will not be repeated here. Each module of the aforementioned engine EGR rate control system for transient operating conditions can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the corresponding operations of each module.

[0041] In one embodiment, a vehicle is provided, comprising: an engine EGR rate control system for transient operating conditions according to any of the above embodiments. The vehicle first determines whether the engine is operating under a high EGR rate condition; if the engine is operating under a high EGR rate condition, it records the current flow rate of fresh air upstream of the intake system and the flow rate of EGR exhaust gas flowing through the EGR valve; then it obtains a delay time, wherein the delay time is the sum of the time required for fresh air and EGR exhaust gas to merge and the time required for the merged gas to enter the engine; then, based on the historical flow rate of fresh air upstream of the intake system before the delay time from the current moment and the historical flow rate of EGR exhaust gas flowing through the EGR valve, it obtains the current instantaneous actual EGR rate of the engine; next, based on the instantaneous actual EGR rate of the engine, it determines whether the misfire boundary is exceeded; if so, it executes a strategy to reduce the target EGR rate or a strategy to disable EGR. Thus, by obtaining the actual EGR rate through the flow rate and delay of fresh air and EGR exhaust gas, and executing a strategy to reduce or disable EGR based on this, the risk of misfire caused by excessively high transient EGR rates is reduced.

[0042] Furthermore, other components and functions of the vehicle according to the embodiments of this application are known to those skilled in the art and will not be described in detail here.

[0043] In one embodiment, a computer device is provided. Figure 8 This is a structural block diagram of the computer device provided in the embodiments of this application, with reference to... Figure 8 The computer device includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the aforementioned embodiment of the engine EGR rate control method for transient operating conditions. For example, it executes: determining whether the engine is operating under a high EGR rate condition; If the engine is operating at a high EGR rate, record the current flow rate of fresh air upstream of the intake system and the flow rate of EGR exhaust gas flowing through the EGR valve. The delay time is obtained, wherein the delay time is the sum of the time required for fresh air and EGR exhaust gas to merge and the time required for the merged gas to enter the engine; The engine's transient actual EGR rate at the current moment is obtained by rewinding the historical fresh air flow rate upstream of the intake system from the current moment to the time before the delay, and the historical EGR exhaust gas flow rate through the EGR valve. Based on the actual transient EGR rate of the engine, determine whether the misfire boundary has been exceeded; If so, implement a strategy to reduce the target EGR rate or disable the EGR response strategy.

[0044] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0045] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0046] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for controlling the EGR rate of an engine under transient operating conditions, characterized in that, include: Determine if the engine is operating at a high EGR rate; If the engine is operating at a high EGR rate, record the current flow rate of fresh air upstream of the intake system and the flow rate of EGR exhaust gas flowing through the EGR valve. The delay time is obtained, wherein the delay time is the sum of the time required for fresh air and EGR exhaust gas to merge and the time required for the merged gas to enter the engine; The engine's transient actual EGR rate at the current moment is obtained by rewinding the historical fresh air flow rate upstream of the intake system from the current moment to the time before the delay, and the historical EGR exhaust gas flow rate through the EGR valve. Based on the actual transient EGR rate of the engine, determine whether the misfire boundary has been exceeded; If so, implement a strategy to reduce the target EGR rate or disable the EGR response strategy.

2. The engine EGR rate control method under transient operating conditions according to claim 1, characterized in that, The determination of whether the engine is operating at a high EGR rate includes: Determine whether the actual transient EGR rate of the engine is greater than the EGR rate threshold, wherein the EGR rate threshold is pre-calibrated; If the actual transient EGR rate of the engine is greater than the EGR rate threshold, then the engine is determined to be operating under a high EGR rate condition.

3. The engine EGR rate control method under transient operating conditions according to claim 1, characterized in that, The obtained delay time includes: From the gas flow delay model, the time it takes for fresh air upstream of the intake system to flow to the point where it merges with the EGR exhaust gas, the time it takes for the EGR exhaust gas to flow to the point where it merges with the fresh air upstream of the intake system, and the time it takes for the mixture at the point of merging to flow to the engine are read. The delay time is obtained based on the time it takes for fresh air upstream of the intake system to flow to the point where it merges with the EGR exhaust gas, the time it takes for the EGR exhaust gas to flow to the point where it merges with the fresh air upstream of the intake system, and the time it takes for the mixture at the point of merging to flow to the engine.

4. The engine EGR rate control method under transient operating conditions according to claim 1, characterized in that, The step of obtaining the engine's transient actual EGR rate at the current moment based on the historical fresh air flow rate upstream of the intake system before the delay time from the current moment and the historical EGR exhaust gas flow rate through the EGR valve includes: The actual external EGR rate of the engine is obtained by rewinding the historical fresh air flow rate upstream of the intake system from the current moment to the time before the delay, and the historical EGR exhaust gas flow rate through the EGR valve. The internal EGR rate is read from the engine charging model based on the historical fresh air flow rate before the delay time from the current moment. The transient actual EGR rate of the engine at the current moment is obtained based on the actual external EGR rate and the internal EGR rate of the engine.

5. The engine EGR rate control method under transient operating conditions according to any one of claims 1-4, characterized in that, The step of determining whether the misfire boundary has been exceeded based on the actual transient EGR rate of the engine includes: Determine whether the actual transient EGR rate of the engine exceeds the misfire threshold, wherein the misfire threshold is pre-calibrated; If so, then it is determined that the fire has exceeded the fire boundary.

6. The engine EGR rate control method under transient operating conditions according to claim 5, characterized in that, The strategy for reducing the target EGR rate includes: When it is determined that the fire boundary has been exceeded, the strategy to reduce the target EGR rate is executed, wherein executing the strategy to reduce the target EGR rate includes: Based on the actual transient EGR rate of the engine and the misfire level threshold, when a minor misfire is determined, a product coefficient is obtained, and the reduction in EGR rate is obtained based on the product coefficient. The target EGR rate is then reduced based on the reduction.

7. The engine EGR rate control method under transient operating conditions according to claim 6, characterized in that, Upon determination of a severe fire, an EGR (Exhaust Gas Refrigerant Response) disabling strategy is implemented, which includes: Delay the ignition timing and close the EGR valve.

8. A transient engine EGR rate control system, characterized in that, include: The judgment module is used to determine whether the engine is operating under high EGR rate conditions; The confirmation module is used to record the flow rate of fresh air upstream of the intake system and the flow rate of EGR exhaust gas flowing through the EGR valve at the current moment when the engine is operating at a high EGR rate, and to obtain a delay time. The delay time is the sum of the time required for fresh air and EGR exhaust gas to merge and the time required for the merged gas to enter the engine. Based on the historical flow rate of fresh air upstream of the intake system and the historical flow rate of EGR exhaust gas flowing through the EGR valve before the current moment rewinds the delay time, the transient actual EGR rate of the engine at the current moment is obtained. The control module is used to determine whether the engine's transient actual EGR rate exceeds the misfire boundary, and if the misfire boundary is exceeded, to execute a strategy to reduce the target EGR rate or to disable the EGR response strategy.

9. A vehicle, characterized in that, include: The engine EGR rate control system for transient operating conditions as described in claim 8.

10. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the engine EGR rate control method for transient operating conditions as described in any one of claims 1-7.

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