Control method, device, equipment and medium of transient exhaust gas recirculation system

Abstract

The present invention provides a method, apparatus, device, and medium for controlling a transient exhaust gas recirculation system, including: determining an engine load state based on a first required boost pressure; if the engine load state is a medium-low load condition, determining the engine's required charge change rate based on the throttle opening to determine whether the engine has entered a transient state; if the engine is determined to be in a transient state, determining a first transient degree factor of the exhaust gas recirculation system to a preset fixed value; inputting a first actual speed and a first actual charge into a transient exhaust gas circulation rate MAP and a steady-state exhaust gas circulation rate MAP, respectively, to output a first transient exhaust gas circulation rate and a first steady-state exhaust gas circulation rate; determining a first target EGR rate based on the first transient degree factor, the first transient exhaust gas circulation rate, and the first steady-state exhaust gas circulation rate; and controlling the exhaust gas recirculation system based on the first target EGR rate. The method of the present invention improves the EGR response speed and the initial power of the engine.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of engine technology, and in particular to a control method, device, equipment, and medium for a transient exhaust gas recirculation system. Background Art

[0002] When a natural gas engine is operating at low to medium load or part load, EGR (Exhaust Gas Recirculation) is required to lower combustion temperatures and reduce nitrogen oxide emissions. Controlling EGR is crucial to meeting performance and environmental requirements under dynamic driving conditions.

[0003] In the prior art, the current transient level of the engine is calculated by acquiring data from real-time sensors, and the EGR valve opening is adjusted according to the current transient level.

[0004] However, when the engine is completely in a transient operating state, the system complexity of the existing technology for calculating based on real-time sensor data is high, resulting in a delayed response of the EGR control, which leads to poor initial power performance of the engine. Summary of the Invention

[0005] The embodiments of the present application provide a control method, device, equipment and medium for a transient exhaust gas recirculation system, which are used to solve the problem of delayed response of current EGR control, resulting in poor initial power performance of the engine.

[0006] A first aspect of an embodiment of the present application provides a method for controlling a transient exhaust gas recirculation system, which is applied to a control unit of a vehicle, comprising:

[0007] Obtain the current engine intake volume required, determine the first required boost pressure of the engine based on the required intake volume; determine the engine load state based on the first required boost pressure; if the engine load state is a medium or low load condition, obtain the vehicle's throttle opening, and determine the engine's required charge change rate based on the throttle opening; determine whether the engine has entered a transient condition based on the required charge change rate; if it is determined that the engine is in a transient condition, determine the first transient degree factor of the exhaust gas recirculation system EGR to a preset fixed value, where the transient degree factor represents The transient degree of the engine; obtaining a first actual speed and a first actual charge of the engine at the current moment; inputting the first actual speed and the first actual charge into a pre-calibrated transient exhaust gas circulation rate MAP to output a first transient exhaust gas circulation rate; inputting the first actual speed and the first actual charge into a pre-calibrated steady-state exhaust gas circulation rate MAP to output a first steady-state exhaust gas circulation rate; determining a first target EGR rate based on the first transient degree factor, the first transient exhaust gas circulation rate and the first steady-state exhaust gas circulation rate; and controlling the exhaust gas recirculation system based on the first target EGR rate.

[0008] Optionally, after determining the load state of the engine according to the first required boost pressure, the method further includes: if the load state of the engine is a high-load condition, obtaining the second actual charge of the engine at the current moment, and judging whether the engine is in a transient condition based on the second actual charge; if it is determined that the engine is in a transient condition, obtaining the second actual speed of the engine at the current moment; inputting the second actual speed and the second actual charge into the transient exhaust gas circulation rate MAP to output a second transient exhaust gas circulation rate; inputting the second actual speed and the second actual charge into the steady-state exhaust gas circulation rate MAP to output a second steady-state exhaust gas circulation rate; obtaining the first actual boost pressure of the engine at the current moment; determining the second transient degree factor at the current moment based on the first required boost pressure, the first actual boost pressure and the ambient pressure; determining the second target EGR rate based on the second transient degree factor, the second transient exhaust gas circulation rate and the second steady-state exhaust gas circulation rate; and controlling the exhaust gas recirculation system based on the second target EGR rate.

[0009] Optionally, the second transient degree factor at the current moment is determined according to the first required boost pressure, the first actual boost pressure, and the ambient pressure, using the following formula:

[0010] f2=(Pd1-Pa1) / (Pd1-Pe1)

[0011] Wherein, f2 represents the second transient degree factor, Pd1 represents the first required boost pressure, Pa1 represents the first actual boost pressure, and Pe1 represents the ambient pressure.

[0012] Optionally, the first target EGR rate is determined according to the first transient degree factor, the first transient exhaust gas circulation rate, and the first steady-state exhaust gas circulation rate, using the formula:

[0013] R1=f1(R2 1 -R1 1 )+R1 1

[0014] Where R1 represents the first target EGR rate, f1 represents the first transient degree factor, R2 1 Represents the first transient exhaust gas circulation rate, R1 1 Represents the first steady-state exhaust gas circulation rate.

[0015] Optionally, the preset fixed value of the first transient degree factor is 1.

[0016] Optionally, after controlling the exhaust gas recirculation system according to the first target EGR rate, the further method further includes: continuously monitoring the required intake volume of the engine, and determining a second required boost pressure of the engine according to the required intake volume, wherein the second required boost pressure is greater than the first required boost pressure; when the second required boost pressure is greater than a preset boost threshold, obtaining a third actual charge of the engine at the current moment, and judging whether the engine is in a transient operating condition according to the third actual charge; if it is determined that the engine is in a transient operating condition, obtaining a third actual speed of the engine at the current moment; and comparing the third actual speed and the third actual The charging input is a transient exhaust gas circulation rate MAP to output a third transient exhaust gas circulation rate; the third actual speed and the third actual charging input are a steady-state exhaust gas circulation rate MAP to output a third steady-state exhaust gas circulation rate; the second actual boost pressure of the engine at the current moment is obtained; according to the second required boost pressure, the second actual boost pressure and the ambient pressure, the third transient degree factor at the current moment is determined; according to the third transient degree factor, the third transient exhaust gas circulation rate and the third steady-state exhaust gas circulation rate, the third target EGR rate is determined; according to the third target EGR rate, the exhaust gas recirculation system is controlled.

[0017] A second aspect of an embodiment of the present application provides a control device for a transient exhaust gas recirculation system, comprising:

[0018] The first required pressure determination module is used to obtain the required intake air volume of the engine at a current moment and determine the first required boost pressure of the engine according to the required intake air volume.

[0019] The engine load state determination module is configured to determine the engine load state according to the first required boost pressure.

[0020] The required charge change rate determination module is used to obtain the vehicle's throttle opening if the engine load state is a medium or low load condition, and determine the engine's required charge change rate according to the throttle opening.

[0021] The engine operating condition determination module is used to determine whether the engine enters a transient operating condition based on the required charge change rate.

[0022] The first transient degree factor determination module is configured to determine a first transient degree factor of the exhaust gas recirculation system EGR as a preset fixed value if it is determined that the engine is in a transient operating state, wherein the transient degree factor represents the transient degree of the engine.

[0023] The engine operating parameter acquisition module is used to obtain a first actual speed and a first actual charge of the engine at a current moment.

[0024] The first transient exhaust gas circulation rate output module is configured to input the first actual speed and the first actual charge into a pre-calibrated transient exhaust gas circulation rate MAP to output a first transient exhaust gas circulation rate.

[0025] The first steady-state exhaust gas circulation rate output module is configured to input the first actual speed and the first actual charge into a pre-calibrated steady-state exhaust gas circulation rate MAP to output a first steady-state exhaust gas circulation rate.

[0026] The first target EGR rate determination module is configured to determine a first target EGR rate according to a first transient degree factor, a first transient exhaust gas circulation rate, and a first steady-state exhaust gas circulation rate.

[0027] The exhaust gas recirculation system control module is used to control the exhaust gas recirculation system according to a first target EGR rate.

[0028] A third aspect of an embodiment of the present application provides a control unit for a vehicle, comprising: a memory and a processor;

[0029] Memory stores computer-executable instructions;

[0030] The processor executes the computer-executable instructions stored in the memory to implement the control method of the transient exhaust gas recirculation system according to any one of the first aspects.

[0031] A fourth aspect of an embodiment of the present application provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are executed by a processor, they are used to implement the control method of the transient exhaust gas recirculation system of any one of the first aspects.

[0032] A fifth aspect of an embodiment of the present application provides a computer program product, comprising a computer program, which, when executed by a processor, implements the control method of a transient exhaust gas recirculation system according to any one of the first aspects.

[0033] Embodiments of the present application provide a method, apparatus, device, and medium for controlling a transient exhaust gas recirculation system. The method determines a first required boost pressure of the engine based on the current required engine intake volume. The method then determines the current engine load state based on the first required boost pressure. When the engine is determined to be in a medium-low load state, the method obtains the engine's required charge change rate based on the vehicle's throttle position. The method then determines whether the engine is in a transient operating condition based on the required charge change rate. If the engine is in a medium-low load transient operating condition, the method sets a transient degree factor, which characterizes the degree of engine transients, to a preset fixed value. The method determines a transient exhaust gas recirculation rate based on a transient exhaust gas recirculation rate (MAP), determines a steady-state exhaust gas recirculation rate based on a steady-state exhaust gas recirculation rate (MAP), determines a target exhaust gas recirculation rate (EGR) based on the transient degree factor, the steady-state exhaust gas recirculation rate, and the transient exhaust gas recirculation rate. The exhaust gas recirculation system is then controlled based on the target EGR rate. When the engine is in a medium- and low-load transient operating condition, the transient degree factor that characterizes the transient degree of the engine is set to a preset fixed value. This can reduce the hysteresis of the transient degree factor calculation, improve the response speed of EGR under transient conditions, and improve the initial power of the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0035] Figure 1 This is a diagram of an application scenario of the control method for a transient exhaust gas recirculation system provided in an embodiment of the present application;

[0036] Figure 2 Schematic diagram of the process of controlling the transient exhaust gas recirculation system provided in the embodiment of the present application Figure 1 ;

[0037] Figure 3 Schematic diagram of the process of controlling the transient exhaust gas recirculation system provided in the embodiment of the present application Figure 2 ;

[0038] Figure 4 A schematic structural diagram of a control device for a transient exhaust gas recirculation system provided in an embodiment of the present application;

[0039] Figure 5 A schematic structural diagram of a vehicle control unit provided in an embodiment of the present application.

[0040] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0041] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0042] The technical solution of the present application is described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below with reference to the accompanying drawings.

[0043] To clearly understand the technical solution of this application, we first provide a detailed introduction to the prior art. When a natural gas engine is operating under low- to medium-load and part-load conditions, the exhaust gas recirculation (EGR) system must be activated to lower combustion temperatures and reduce nitrogen oxide emissions. Controlling the EGR system is crucial to meeting performance and environmental requirements under dynamic driving conditions. In the prior art, multiple sensors located at various engine locations, such as intake pressure sensors, exhaust temperature sensors, engine speed sensors, throttle position sensors, and oxygen sensors, monitor various operating parameters in real time. A control unit receives and processes this real-time data, calculating the engine's current transient state using a preset mathematical model or machine learning algorithm. Based on the transient state and a preset control strategy, the optimal opening of the EGR system's valve is calculated, and the valve is adjusted via an actuator. However, when the engine is fully transient, this calculation method exhibits high system complexity, resulting in a delayed response of the EGR system to valve control, leading to poor initial engine performance.

[0044] To address the problem of delayed response to valve control in prior art exhaust gas recirculation systems, resulting in poor initial engine performance, the inventors discovered a solution. The first required boost pressure is determined based on the current engine intake air volume. The current engine load state is then determined based on the first required boost pressure. When the engine is determined to be in a medium-low load state, the engine's required charge change rate is obtained based on the vehicle's throttle position. Based on the required charge change rate, the engine is determined to be in a transient operating condition. If the engine is in a medium-low load transient operating condition, a transient degree factor, representing the degree of engine transients, is set to a preset fixed value. The transient exhaust gas recirculation rate is determined based on the transient exhaust gas recirculation rate MAP, and the steady-state exhaust gas recirculation rate is determined based on the steady-state exhaust gas recirculation rate MAP. A target EGR rate is determined based on the transient degree factor, the steady-state exhaust gas recirculation rate, and the transient exhaust gas recirculation rate. The exhaust gas recirculation system is then controlled based on the target EGR rate. This approach improves the response speed of EGR control and enhances the engine's initial performance.

[0045] Based on the above creative findings, the inventor proposed the technical solution of this application.

[0046] Figure 1 This is an application scenario diagram of the control method of the transient exhaust gas recirculation system provided in the embodiment of the present application. Figure 1 As shown, the specific scenario of this application includes: a vehicle control unit 101, an engine 102 and an exhaust gas recirculation system 103.

[0047] Among them, the vehicle's control unit 101 is responsible for managing and coordinating the operation of various subsystems of the vehicle. It is usually an electronic control module that integrates hardware and software to process data from various sensors and make decisions based on this data to optimize the performance of the vehicle.

[0048] The exhaust gas recirculation system 103 reintroduces a portion of the engine's exhaust gas into the intake system to lower the combustion temperature, thereby reducing the generation of nitrogen oxides.

[0049] Specifically, the vehicle control unit 101 obtains the required intake volume of the engine 102 at the current moment, determines the first required boost pressure of the engine 102 according to the required intake volume; determines the load state of the engine 102 according to the first required boost pressure; if the load state of the engine 102 is a medium or low load condition, obtains the throttle opening of the vehicle, and determines the required charge change rate of the engine 102 according to the throttle opening; determines whether the engine 102 enters a transient condition according to the required charge change rate; if it is determined that the engine 102 is in a transient condition, exhaust gas is discharged. A first transient degree factor of the exhaust gas recirculation system (EGR) 103 is determined to be a preset fixed value; a first actual speed and a first actual charge of the engine 102 at a current moment are obtained; the first actual speed and the first actual charge are input into a pre-calibrated transient exhaust gas recirculation rate (MAP) to output a first transient exhaust gas recirculation rate; the first actual speed and the first actual charge are input into a pre-calibrated steady-state exhaust gas recirculation rate (MAP) to output a first steady-state exhaust gas recirculation rate; a first target exhaust gas recirculation rate is determined based on the first transient degree factor, the first transient exhaust gas recirculation rate, and the first steady-state exhaust gas recirculation rate. The exhaust gas recirculation system 103 is controlled based on the first target EGR rate.

[0050] The embodiments of the present application are introduced below with reference to the accompanying drawings.

[0051] Figure 2 Schematic diagram of the process of controlling the transient exhaust gas recirculation system provided in the embodiment of the present application Figure 1 The execution entity of this embodiment is Figure 1 The vehicle control unit shown in FIG. 1 may also be other devices with similar functions, and this embodiment does not impose any particular restrictions thereon. Figure 2 As shown, the method includes:

[0052] S201: Obtain the current required intake air volume of the engine, and determine a first required boost pressure of the engine according to the required intake air volume.

[0053] Specifically, the required air intake volume of the engine at the current moment is obtained in real time through sensors, and the obtained required air intake volume data is preprocessed by filtering, denoising and outlier processing. Based on the engine's required air intake volume-required boost pressure characteristic curve, the engine's first required boost pressure is determined using a table lookup method.

[0054] The required intake air volume-required boost pressure characteristic curve of the engine is a pre-established mapping relationship between the required intake air volume and the required boost pressure.

[0055] S202: Determine the load state of the engine according to the first required boost pressure.

[0056] The load state of the engine can be a low load condition, a medium load condition, and a high load condition.

[0057] For example, if the obtained first required boost pressure is less than 1300 hPa, it is determined that the engine is in a medium-low load condition; and if the obtained first required boost pressure is greater than 1300 hPa, it is determined that the engine is in a high-load condition.

[0058] S203: If the load state of the engine is a medium-low load condition, the throttle opening of the vehicle is obtained, and the required charge change rate of the engine is determined according to the throttle opening.

[0059] The demand charge rate of change refers to the rate of change in the engine's required intake air volume per unit time. It reflects the engine's dynamic demand for intake air volume under different operating conditions. The throttle opening directly reflects the vehicle's demand for engine power output. Changes in throttle opening lead to changes in the engine's intake air volume, which in turn affects the demand charge rate of change.

[0060] Specifically, if the engine load is low or medium, the throttle position sensor obtains the vehicle's throttle opening in real time. A lookup table is used to determine the engine's required charge rate change rate based on the engine's required charge rate change rate versus throttle opening characteristic curve, which is a pre-established mapping between the required charge rate change rate and throttle opening.

[0061] S204: Determine whether the engine enters a transient operating condition based on the required charge change rate.

[0062] Specifically, whether the engine enters the transient state is determined based on whether the required charge change rate is greater than a preset value T1. When the required charge change rate is greater than the preset value T1, the engine is determined to have entered the transient state. The preset value T1 is determined based on human experience.

[0063] S205: If it is determined that the engine is in a transient operating condition, a first transient degree factor of the exhaust gas recirculation system EGR is determined to be a preset fixed value, wherein the transient degree factor represents the transient degree of the engine.

[0064] The transient degree factor is a coefficient that characterizes the transient degree of the engine. The transient degree factor has a value between 0 and 1, and the closer the transient degree factor is to 1, the higher the transient degree.

[0065] In an optional implementation, if it is determined that the engine is in a transient operating state, the preset fixed value of the first transient degree factor of the EGR of the exhaust gas recirculation system is set to 1.

[0066] In another optional implementation, if it is determined that the engine is in a transient operating condition, the preset fixed value of the first transient degree factor of the exhaust gas recirculation system EGR is set to any value between 0.9 and 1.

[0067] S206: Obtain a first actual speed and a first actual charge amount of the engine at the current moment.

[0068] Specifically, the engine control unit collects data from the speed sensor in real time, filters and de-noises the collected data, and obtains the processed first actual speed. The engine control unit collects data from the intake flow sensor or intake pressure sensor in real time, filters and de-noises the collected data, and obtains the processed first actual charge. The engine speed sensor is usually installed on the crankshaft or camshaft, and determines the engine speed by detecting the frequency of rotation. The intake flow sensor directly measures the mass flow of air entering the engine, while the intake pressure sensor measures the absolute pressure of the intake manifold. The first actual charge is obtained through calculation.

[0069] S207: Input the first actual speed and the first actual charge into a pre-calibrated transient exhaust gas circulation rate MAP to output a first transient exhaust gas circulation rate.

[0070] The pre-calibrated transient EGR rate (MAP) maps the EGR rate under transient conditions to actual engine speed and charge. This MAP is based on engine test data and simulation results, and covers the optimal EGR rate for various combinations of actual engine speed and charge under transient conditions.

[0071] Specifically, the first actual speed and the first actual charge are input into a pre-calibrated transient exhaust gas circulation MAP, and the corresponding EGR rate is searched to determine the first transient exhaust gas circulation rate.

[0072] S208: Input the first actual speed and the first actual charge into a pre-calibrated steady-state exhaust gas circulation rate MAP to output a first steady-state exhaust gas circulation rate.

[0073] The pre-calibrated Steady-State Exhaust Gas Recirculation Rate (MAP) maps the EGR rate under steady-state conditions to actual engine speed and charge. This MAP is based on engine test data and simulation results, and covers the optimal EGR rate for various combinations of actual engine speed and charge under steady-state conditions.

[0074] Specifically, the first actual speed and the first actual charge are input into a pre-calibrated steady-state exhaust gas circulation MAP, and the corresponding EGR rate is searched to determine the first steady-state exhaust gas circulation rate.

[0075] S209: Determine a first target EGR rate according to the first transient degree factor, the first transient exhaust gas circulation rate, and the first steady-state exhaust gas circulation rate.

[0076] Specifically, the formula for determining the first target EGR rate is:

[0077] R1=f1(R2 1 -R1 1 )+R1 1

[0078] Where R1 represents the first target EGR rate, f1 represents the first transient degree factor, which is 1, and R2 1 Represents the first transient exhaust gas circulation rate, R1 1 Represents the first steady-state exhaust gas circulation rate.

[0079] S210: Control the exhaust gas recirculation system according to the first target EGR rate.

[0080] Specifically, the actual EGR rate is monitored in real time through an EGR flow sensor or other related sensors, the error between the first target EGR rate and the actual EGR rate is calculated, and a feedback control algorithm such as PID control is used to adjust the opening of the EGR valve. The opening of the EGR valve is adjusted in real time according to the adjustment amount calculated by the feedback control algorithm, and precise control of the EGR valve is achieved through an actuator such as an electric or pneumatic actuator.

[0081] In summary, the engine's first required boost pressure is determined based on the current engine intake air volume, and the engine's load state is determined based on the first required boost pressure. When the engine is determined to be in a medium-low load state, the engine's required charge change rate is obtained based on the vehicle's throttle opening, and the engine's transient operating condition is determined based on the required charge change rate. If the engine is in a medium-low load transient operating condition, a transient degree factor, representing the engine's transient degree, is set to a preset fixed value. The transient exhaust gas recirculation rate is determined based on the transient exhaust gas recirculation rate MAP, and the steady-state exhaust gas recirculation rate is determined based on the steady-state exhaust gas recirculation rate MAP. A target EGR rate is determined based on the transient degree factor, the steady-state exhaust gas recirculation rate, and the transient exhaust gas recirculation rate, and the exhaust gas recirculation system is controlled based on the target EGR rate. When the engine is in a medium-low load transient operating condition, setting the transient degree factor, representing the engine's transient degree, to a preset fixed value can reduce hysteresis in the transient degree factor calculation, improve EGR response speed under transient conditions, and enhance engine power performance in the initial stage.

[0082] Figure 3 Schematic diagram of the process of controlling the transient exhaust gas recirculation system provided in the embodiment of the present application Figure 2 After determining the engine load state according to the first required boost pressure, if the engine load state is a high load condition, the method for controlling the exhaust gas recirculation system EGR further includes:

[0083] S301: If the load state of the engine is a high-load operating condition, a second actual charge of the engine at the current moment is obtained, and whether the engine is in a transient operating condition is determined based on the second actual charge.

[0084] Specifically, an intake air flow sensor or an intake air pressure sensor is used to measure a second actual charge of the engine, and a rate of change of the actual charge per unit time is obtained to obtain a second actual charge change rate. If the second actual charge change rate is greater than a set value T2, the engine is determined to have entered a transient state. The set value T2 is determined based on human experience.

[0085] S302: If it is determined that the engine is in a transient operating state, a second actual speed of the engine at the current moment is obtained.

[0086] Specifically, if it is determined that the engine is in a transient operating condition, the engine control unit collects data from the speed sensor in real time, and performs filtering and denoising on the collected data to obtain a processed second actual speed at the current moment.

[0087] S303: Input the second actual speed and the second actual charge into the transient exhaust gas circulation rate MAP to output a second transient exhaust gas circulation rate.

[0088] Specifically, the second actual speed and the second actual charge are input into a pre-calibrated transient exhaust gas circulation MAP, and the corresponding EGR rate is searched to determine the second transient exhaust gas circulation rate.

[0089] S304: Input the second actual speed and the second actual charge into the steady-state exhaust gas circulation rate MAP to output a second steady-state exhaust gas circulation rate.

[0090] Specifically, the second actual speed and the second actual charge are input into a pre-calibrated steady-state exhaust gas circulation MAP, and the corresponding EGR rate is searched to determine the second steady-state exhaust gas circulation rate.

[0091] S305: Obtain the first actual boost pressure of the engine at the current moment.

[0092] Specifically, a boost pressure sensor installed at the intake manifold or the supercharger outlet is used to obtain the first actual boost pressure of the engine at the current moment in real time.

[0093] S306: Determine a second transient degree factor at the current moment according to the first required boost pressure, the first actual boost pressure, and the ambient pressure.

[0094] The ambient pressure is the atmospheric pressure at the current moment.

[0095] Specifically, the formula for determining the second transient degree factor at the current moment is:

[0096] f2=(Pd1-Pa1) / (Pd1-Pe1)

[0097] Wherein, f2 represents the second transient degree factor, Pd1 represents the first required boost pressure, Pa1 represents the first actual boost pressure, and Pe1 represents the ambient pressure.

[0098] S307: Determine a second target EGR rate according to the second transient degree factor, the second transient exhaust gas circulation rate, and the second steady-state exhaust gas circulation rate.

[0099] Specifically, the formula for determining the second target EGR rate is:

[0100] R2=f2(R2 2 -R1 2 )+R1 2

[0101] Where, R2 represents the second target EGR rate, f2 represents the second transient degree factor, R2 2 Represents the second transient exhaust gas circulation rate, R1 2 Indicates the second steady-state exhaust gas circulation rate.

[0102] S308: Control the exhaust gas recirculation system according to the second target EGR rate.

[0103] Specifically, the actual EGR rate is monitored in real time through an EGR flow sensor or other related sensors, the error between the second target EGR rate and the actual EGR rate is calculated, and a feedback control algorithm such as PID control is used to adjust the opening of the EGR valve. The opening of the EGR valve is adjusted in real time according to the adjustment amount calculated by the feedback control algorithm, and precise control of the EGR valve is achieved through an actuator such as an electric or pneumatic actuator.

[0104] In summary, after determining that the engine load state is a high-load condition based on the first required boost pressure, the current second actual engine charge is used to determine whether the engine is currently in a transient condition. When the engine is in a high-load transient condition, a second transient severity factor is calculated based on the first required boost pressure, the current first actual engine boost pressure, and the ambient pressure. A second transient exhaust gas circulation rate and a second steady-state exhaust gas circulation rate are output based on the current second actual engine speed and the second actual charge. The second transient severity factor, the second transient exhaust gas circulation rate, and the second steady-state exhaust gas circulation rate are used to determine a second target EGR rate for the engine under the current condition to control the exhaust gas recirculation system. When the engine is in a high-load transient condition, calculating the second transient severity factor based on the current first actual engine boost pressure and the ambient pressure can reduce the difference in transient severity between the engine's low- and medium-load transient conditions and its high-load transient conditions, thereby reducing the level of engine knock under high-load transient conditions.

[0105] In another embodiment of the present application, after the exhaust gas recirculation system is controlled according to the first target EGR rate, as the required intake air volume of the engine continues to increase with the operating state of the vehicle, the method for controlling the exhaust gas recirculation system further includes:

[0106] S401: Continuously monitor the required intake air volume of the engine, and determine a second required boost pressure of the engine according to the required intake air volume, wherein the second required boost pressure is greater than the first required boost pressure.

[0107] Specifically, the required air intake volume of the engine at the current moment is obtained in real time through the sensor. After filtering, denoising and outlier processing of the obtained required air intake volume data, the second required boost pressure of the engine is determined based on the required air intake volume-required boost pressure characteristic curve of the engine using a table lookup method, where the second required boost pressure is greater than the first required boost pressure.

[0108] S402: When the second required boost pressure is greater than the preset boost threshold, a third actual charge of the engine at the current moment is obtained, and whether the engine is in a transient operating condition is determined based on the third actual charge.

[0109] Specifically, an intake air flow sensor or an intake air pressure sensor is used to actually measure a third actual charge of the engine, and the rate of change of the actual charge per unit time is obtained to obtain a third actual charge change rate. If the third actual charge change rate is greater than a set value T2, it is determined that the engine has entered a transient state. The set value T2 is determined based on human experience.

[0110] S403: If it is determined that the engine is in a transient operating state, a third actual speed of the engine at the current moment is obtained.

[0111] Specifically, if it is determined that the engine is in a transient operating condition, the engine control unit collects data from the speed sensor in real time, and performs filtering and denoising processing on the collected data to obtain a processed third actual speed at the current moment.

[0112] S404: Input the third actual speed and the third actual charge into the transient exhaust gas circulation rate MAP to output a third transient exhaust gas circulation rate.

[0113] Specifically, the third actual speed and the third actual charge are input into a pre-calibrated transient exhaust gas circulation MAP, and the corresponding EGR rate is searched to determine the third transient exhaust gas circulation rate.

[0114] S405: Input the third actual speed and the third actual charge into the steady-state exhaust gas circulation rate MAP to output a third steady-state exhaust gas circulation rate.

[0115] Specifically, the third actual speed and the third actual charge are input into a pre-calibrated steady-state exhaust gas circulation MAP, and the corresponding EGR rate is searched to determine the third steady-state exhaust gas circulation rate.

[0116] S406: Obtain the second actual boost pressure of the engine at the current moment.

[0117] Specifically, a boost pressure sensor installed at the intake manifold or the outlet of the supercharger is used to obtain the second actual boost pressure of the engine at the current moment in real time.

[0118] S407: Determine a third transient degree factor at the current moment according to the second required boost pressure, the second actual boost pressure, and the ambient pressure.

[0119] Specifically, the formula for determining the third transient degree factor at the current moment is:

[0120] f3=(Pd2-Pa2) / (Pd2-Pe2)

[0121] Wherein, f3 represents the third transient degree factor, Pd2 represents the second required boost pressure, Pa2 represents the second actual boost pressure, and Pe2 represents the ambient pressure at the current moment.

[0122] S408: Determine a third target EGR rate according to the third transient degree factor, the third transient exhaust gas circulation rate, and the third steady-state exhaust gas circulation rate.

[0123] Specifically, the formula for determining the third target EGR rate is:

[0124] R3=f3(R2 3 -R1 3 )+R1 3

[0125] Where, R3 represents the third target EGR rate, f3 represents the third transient degree factor, R2 3 Indicates the third transient exhaust gas circulation rate, R1 3 Indicates the third steady-state exhaust gas circulation rate.

[0126] S409: Control the exhaust gas recirculation system according to the third target EGR rate.

[0127] Specifically, the actual EGR rate is monitored in real time through an EGR flow sensor or other related sensors, the error between the third target EGR rate and the actual EGR rate is calculated, and a feedback control algorithm such as PID control is used to adjust the opening of the EGR valve. The opening of the EGR valve is adjusted in real time according to the adjustment amount calculated by the feedback control algorithm, and precise control of the EGR valve is achieved through an actuator such as an electric or pneumatic actuator.

[0128] In summary, when the required intake volume of the engine continues to increase, the second required boost pressure is obtained according to the current required intake volume of the engine, and after determining that the load state of the engine is a high-load condition, the third actual charge of the engine at the current moment is used to judge whether the engine is currently in a transient condition. When the engine is in a high-load transient condition, the third transient degree factor at the current moment is calculated according to the second required boost pressure, the second actual boost pressure of the engine at the current moment, and the ambient pressure, and the third transient exhaust gas circulation factor is output according to the third actual speed and the third actual charge of the engine at the current moment. The third target EGR rate of the engine under the current working condition is determined by using the third transient degree factor, the third transient exhaust gas circulation rate and the third steady-state exhaust gas circulation rate to control the exhaust gas recirculation system. When the engine changes from a low-load transient working condition to a high-load transient working condition, the third transient degree factor is calculated according to the second actual boost pressure of the engine and the ambient pressure at the current moment. This can reduce the transient degree gap when the engine changes from medium and low-load transient working conditions to high-load transient working conditions, thereby further reducing the knock level of the engine under high-load transient working conditions.

[0129] Figure 4 This is a schematic diagram of the structure of the control device of the transient exhaust gas recirculation system provided in the embodiment of the present application. Figure 4 As shown, the control device of the transient exhaust gas recirculation system includes a first demand pressure determination module 401, an engine load state determination module 402, a demand charging change rate determination module 403, an engine operating condition determination module 404, a first transient degree factor determination module 405, an engine operating parameter acquisition module 406, a first transient exhaust gas circulation rate output module 407, a first steady-state exhaust gas circulation rate output module 408, a first target EGR rate determination module 409 and an exhaust gas recirculation system control module 410.

[0130] The first required pressure determination module 401 is configured to obtain the required intake air volume of the engine at a current moment and determine the first required boost pressure of the engine according to the required intake air volume.

[0131] The engine load state determination module 402 is configured to determine the engine load state according to the first required boost pressure.

[0132] The required charge change rate determination module 403 is configured to obtain the throttle opening of the vehicle if the engine load state is a medium or low load condition, and determine the required charge change rate of the engine according to the throttle opening.

[0133] The engine operating condition determination module 404 is configured to determine whether the engine has entered a transient operating condition based on the required charge change rate.

[0134] The first transient degree factor determination module 405 is configured to determine a first transient degree factor of the exhaust gas recirculation system EGR as a preset fixed value if it is determined that the engine is in a transient operating state, wherein the transient degree factor represents the transient degree of the engine.

[0135] The engine operating parameter acquisition module 406 is configured to acquire a first actual speed and a first actual charge of the engine at a current moment.

[0136] The first transient exhaust gas circulation rate output module 407 is configured to input the first actual speed and the first actual charge into a pre-calibrated transient exhaust gas circulation rate MAP to output a first transient exhaust gas circulation rate.

[0137] The first steady-state exhaust gas recirculation rate output module 408 is configured to input the first actual speed and the first actual charge into a pre-calibrated steady-state exhaust gas recirculation rate MAP to output a first steady-state exhaust gas recirculation rate.

[0138] The first target EGR rate determination module 409 is configured to determine a first target EGR rate according to a first transient degree factor, a first transient exhaust gas circulation rate, and a first steady-state exhaust gas circulation rate.

[0139] The exhaust gas recirculation system control module 410 is configured to control the exhaust gas recirculation system according to a first target EGR rate.

[0140] Optionally, the control device of the transient exhaust gas recirculation system also includes a high-load transient operating condition exhaust gas recirculation system control module, which is used to obtain the second actual charge of the engine at the current moment if the load state of the engine is a high-load operating condition, and determine whether the engine is in a transient operating condition based on the second actual charge; if it is determined that the engine is in a transient operating condition, obtain the second actual speed of the engine at the current moment; input the second actual speed and the second actual charge into the transient exhaust gas circulation rate MAP to output a second transient exhaust gas circulation rate; input the second actual speed and the second actual charge into the steady-state exhaust gas circulation rate MAP to output a second steady-state exhaust gas circulation rate; obtain the first actual boost pressure of the engine at the current moment; determine the second transient degree factor at the current moment based on the first required boost pressure, the first actual boost pressure and the ambient pressure; determine the second target EGR rate based on the second transient degree factor, the second transient exhaust gas circulation rate and the second steady-state exhaust gas circulation rate; and control the exhaust gas recirculation system based on the second target EGR rate.

[0141] Optionally, the high-load transient exhaust gas recirculation system control module is further configured to continuously monitor the engine's required intake volume, and determine a second required boost pressure of the engine based on the required intake volume, wherein the second required boost pressure is greater than the first required boost pressure; when the second required boost pressure is greater than a preset boost threshold, obtain a third actual charge of the engine at the current moment, and determine whether the engine is in a transient operating condition based on the third actual charge; if it is determined that the engine is in a transient operating condition, obtain a third actual speed of the engine at the current moment; input the third actual speed and the third actual charge into The method comprises the following steps: inputting a third actual speed and a third actual charge into the steady-state exhaust gas circulation rate MAP to output a third steady-state exhaust gas circulation rate; obtaining a second actual boost pressure of the engine at the current moment; determining a third transient degree factor at the current moment according to the second required boost pressure, the second actual boost pressure and the ambient pressure; determining a third target EGR rate according to the third transient degree factor, the third transient exhaust gas circulation rate and the third steady-state exhaust gas circulation rate; and controlling the exhaust gas recirculation system according to the third target EGR rate.

[0142] Optionally, the formula for determining the second transient degree factor at the current moment in the high-load transient exhaust gas recirculation system control module is:

[0143] f2=(Pd1-Pa1) / (Pd1-Pe1) wherein f2 represents the second transient degree factor, Pd1 represents the first required boost pressure, Pa1 represents the first actual boost pressure, and Pe1 represents the ambient pressure.

[0144] Wherein, f2 represents the second transient degree factor, Pd1 represents the first required boost pressure, Pa1 represents the first actual boost pressure, and Pe1 represents the ambient pressure.

[0145] Optionally, the formula for determining the first target EGR rate in the first target EGR rate determination module 409 is:

[0146] R1=f1(R2 1 -R1 1 )+R1 1

[0147] Where R1 represents the first target EGR rate, f1 represents the first transient degree factor, R2 1 Represents the first transient exhaust gas circulation rate, R1 1 Represents the first steady-state exhaust gas circulation rate.

[0148] The control device for the transient exhaust gas recirculation system provided in this embodiment can implement the technical solution of the above method embodiment. Its implementation principle and technical effects are similar to those of the above method embodiment, and will not be described in detail here.

[0149] According to an embodiment of the present application, a control unit of a vehicle, a computer-readable storage medium, and a computer program product are also provided.

[0150] like Figure 5 As shown, Figure 5 This is a schematic diagram of the structure of a vehicle control unit provided in an embodiment of the present application. The vehicle control unit is intended to include various electronic devices, such as microcomputers and single-chip microcomputers, that can be used to implement the control method for a transient exhaust gas recirculation system. The components, their connections and relationships, and their functions shown herein are merely examples and are not intended to limit the implementation of the embodiments of the present application described and / or claimed herein.

[0151] like Figure 5 As shown, the control unit of the vehicle includes: a processor 501 and a memory 502. The memory stores computer-executable instructions; the processor executes the computer-executable instructions stored in the memory to implement the control method of the transient exhaust gas recirculation system of the above embodiment.

[0152] The memory 502 is a computer-readable storage medium provided in the embodiment of the present application. The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the control method of the transient exhaust gas recirculation system of the above embodiment.

[0153] Memory 502, as a computer-readable storage medium, can be used to store software programs, computer-executable programs, and modules, such as the program instructions / modules corresponding to the transient exhaust gas recirculation system control method in the embodiments of the present application. Processor 501 executes the software programs, instructions, and modules stored in memory 502 to perform various functional applications and data processing, thereby implementing the transient exhaust gas recirculation system control method in the aforementioned method embodiment.

[0154] At the same time, this embodiment also provides a computer program product, including a computer program. When the instructions in the computer product are executed by a processor, the control method of the transient exhaust gas recirculation system of the above embodiment can be executed.

[0155] Those skilled in the art will readily conceive of other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention, which follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed in the present invention. The specification and examples are to be considered merely as exemplary, and the true scope and spirit of the present invention are indicated by the claims.

[0156] It should be understood that the embodiments of the present application are not limited to the precise structures described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the embodiments of the present application is limited only by the appended claims.

Claims

1. A method for controlling a transient exhaust gas recirculation system, characterized in that: Control units used in vehicles, including: Obtaining a current required intake air volume of the engine, and determining a first required boost pressure of the engine according to the required intake air volume; determining a load state of the engine according to the first required boost pressure; If the load state of the engine is a medium-low load condition, obtaining the throttle opening of the vehicle, and determining the required charge change rate of the engine according to the throttle opening; determining whether the engine enters a transient operating condition according to the required charge change rate; If it is determined that the engine is in a transient operating condition, a first transient degree factor of the exhaust gas recirculation system (EGR) is determined to be a preset fixed value, wherein the transient degree factor represents the transient degree of the engine; Obtaining a first actual speed and a first actual charge of the engine at a current moment; Inputting the first actual speed and the first actual charge into a pre-calibrated transient exhaust gas circulation rate MAP to output a first transient exhaust gas circulation rate; Inputting the first actual speed and the first actual charge into a pre-calibrated steady-state exhaust gas circulation rate MAP to output a first steady-state exhaust gas circulation rate; determining a first target EGR rate according to the first transient degree factor, the first transient exhaust gas circulation rate, and the first steady-state exhaust gas circulation rate; The exhaust gas recirculation system is controlled according to the first target EGR rate.

2. The method according to claim 1, characterized in that After determining the load state of the engine according to the first required boost pressure, the method further includes: If the load state of the engine is a high-load operating condition, obtaining a second actual charge of the engine at a current moment, and determining whether the engine is in a transient operating condition based on the second actual charge; If it is determined that the engine is in a transient operating state, obtaining a second actual speed of the engine at the current moment; inputting the second actual speed and the second actual charge into the transient exhaust gas circulation rate MAP to output a second transient exhaust gas circulation rate; inputting the second actual speed and the second actual charge into the steady-state exhaust gas circulation rate MAP to output a second steady-state exhaust gas circulation rate; Obtaining a first actual boost pressure of the engine at a current moment; determining a second transient degree factor at a current moment according to the first required boost pressure, the first actual boost pressure, and the ambient pressure; determining a second target EGR rate according to the second transient degree factor, the second transient exhaust gas circulation rate, and the second steady-state exhaust gas circulation rate; The exhaust gas recirculation system is controlled according to the second target EGR rate.

3. The method according to claim 2, characterized in that The formula for determining the second transient degree factor at the current moment according to the first required boost pressure, the first actual boost pressure and the ambient pressure is: f2=(Pd1-Pa1) / (Pd1-Pe1) In the formula, f2 represents the second transient degree factor, Pd1 represents the first required boost pressure, Pa1 represents the first actual boost pressure, and Pe1 represents the ambient pressure.

4. The method according to claim 1, wherein The formula for determining the first target EGR rate according to the first transient degree factor, the first transient exhaust gas circulation rate, and the first steady-state exhaust gas circulation rate is: R1=f1(R2 1 -R1 1 )+R1 1 Where, R1 represents the first target EGR rate, f1 represents the first transient degree factor, R2 1 represents the first transient exhaust gas circulation rate, R1 1 represents the first steady-state exhaust gas circulation rate.

5. The method according to claim 1, wherein The preset fixed value of the first transient degree factor is 1.

6. The method according to claim 1, characterized in that After controlling the exhaust gas recirculation system according to the first target EGR rate, the method further includes: continuously monitoring a required intake air volume of the engine, and determining a second required boost pressure of the engine according to the required intake air volume, wherein the second required boost pressure is greater than the first required boost pressure; When the second required boost pressure is greater than a preset boost threshold, obtaining a third actual charge of the engine at a current moment, and determining whether the engine is in a transient operating condition based on the third actual charge; If it is determined that the engine is in a transient operating state, obtaining a third actual speed of the engine at the current moment; inputting the third actual speed and the third actual charge into the transient exhaust gas circulation rate MAP to output a third transient exhaust gas circulation rate; inputting the third actual speed and the third actual charge into the steady-state exhaust gas circulation rate MAP to output a third steady-state exhaust gas circulation rate; Obtaining a second actual boost pressure of the engine at a current moment; determining a third transient degree factor at a current moment according to the second required boost pressure, the second actual boost pressure, and the ambient pressure; determining a third target EGR rate according to the third transient degree factor, the third transient exhaust gas circulation rate, and the third steady-state exhaust gas circulation rate; The exhaust gas recirculation system is controlled according to the third target EGR rate.

7. A control device for a transient exhaust gas recirculation system, characterized in that: Control units used in vehicles, including: a first required pressure determination module, configured to obtain a required intake air volume of the engine at a current moment, and determine a first required boost pressure of the engine according to the required intake air volume; an engine load state determining module, configured to determine the load state of the engine according to the first required boost pressure; a required charge change rate determination module, configured to obtain a throttle opening of the vehicle if the load state of the engine is a medium or low load condition, and determine a required charge change rate of the engine according to the throttle opening; an engine operating condition determination module, configured to determine whether the engine has entered a transient operating condition based on the required charge change rate; a first transient degree factor determining module, configured to determine a first transient degree factor of the exhaust gas recirculation system (EGR) as a preset fixed value if it is determined that the engine is in a transient operating condition, wherein the transient degree factor represents a transient degree of the engine; an engine operating parameter acquisition module, configured to acquire a first actual speed and a first actual charge of the engine at a current moment; a first transient exhaust gas circulation rate output module, configured to input the first actual speed and the first actual charge into a pre-calibrated transient exhaust gas circulation rate MAP to output a first transient exhaust gas circulation rate; a first steady-state exhaust gas circulation rate output module, configured to input the first actual speed and the first actual charge into a pre-calibrated steady-state exhaust gas circulation rate MAP to output a first steady-state exhaust gas circulation rate; a first target EGR rate determining module, configured to determine a first target EGR rate according to the first transient degree factor, the first transient exhaust gas circulation rate, and the first steady-state exhaust gas circulation rate; An exhaust gas recirculation system control module is used to control the exhaust gas recirculation system according to the first target EGR rate.

8. A control unit of a vehicle, characterized in that: include: memory and processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory to implement the control method of the transient exhaust gas recirculation system according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer-executable instructions, which are used to implement the control method of the transient exhaust gas recirculation system according to any one of claims 1 to 6 when executed by a processor.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the control method of the transient exhaust gas recirculation system according to any one of claims 1 to 6 is implemented.

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