Engine system and EGR cooler bypass valve control method

Abstract

The present application provides a control method for an engine system and an EGR cooler bypass valve, which is applied to the ECU in the engine system, including: determining the optimal temperature corresponding to the exhaust gas output by the EGR cooler based on the acquired current speed and current torque; wherein the optimal temperature is the exhaust gas temperature corresponding to the optimal operating condition when the engine runs at the current speed and current torque while meeting specific performance requirements; based on the optimal temperature, determining the valve opening value of the bypass valve in the EGR cooler, and adjusting the valve opening size of the bypass valve to the valve opening value, which can not only achieve the optimal state of engine performance and emissions under the premise of ensuring engine reliability, but also improve the working efficiency of EGR by adjusting the valve opening size of the bypass valve in the EGR cooler while meeting the specific performance requirements of the engine.

Description

Technical Field

[0001] The present invention relates to the field of control technology, and in particular to a control method for an engine system and an EGR cooler bypass valve. Background Art

[0002] With the continuous upgrading of domestic and international emission regulations, nitrogen oxide (NOx) emissions are becoming increasingly stringent. For diesel engines, exhaust gas recirculation (EGR) is a common and key measure for reducing NOx. Its operating principle is to introduce a portion of the diesel engine's exhaust gas into the intake system, where it mixes with fresh air before entering the cylinder for combustion. This reduces the combustion temperature and oxygen concentration of the mixture within the cylinder, thereby suppressing the production of NOx in the diesel engine and meeting emission regulations.

[0003] The exhaust gas from a diesel engine generally contains corrosive substances such as soot and sulfides. When the exhaust temperature is too low, the corrosive substances in the exhaust gas will cause carbon deposition and coking in the EGR cooler, resulting in blockage of the EGR cooler and valve sticking, resulting in reduced cooling efficiency. When the exhaust temperature is too high, the engine's emissions and performance will deteriorate and cannot meet emission requirements. Therefore, how to improve the working efficiency of EGR while meeting engine performance requirements is an urgent problem that needs to be solved. Summary of the Invention

[0004] In this regard, the present application provides an engine system and an EGR cooler bypass valve control method, which can improve the EGR working efficiency and achieve the optimal state of engine performance and emissions by adjusting the valve opening size of the bypass valve in the EGR cooler while meeting the specific performance requirements of the engine.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] In a first aspect, the present application discloses a control method for an EGR cooler bypass valve, which is applied to an ECU in an engine system. The control method includes:

[0007] Get the current speed and current torque of the engine;

[0008] determining an optimal temperature corresponding to exhaust gas output by the EGR cooler based on the current speed and the current torque; wherein the optimal temperature is the exhaust gas temperature corresponding to an optimal operating condition when the engine is running at the current speed and the current torque while meeting specific performance requirements;

[0009] Based on the optimal temperature, a valve port opening value of the bypass valve in the EGR cooler is determined, and the valve port opening size of the bypass valve is adjusted to the valve port opening value.

[0010] Optionally, in the above-mentioned EGR cooler bypass valve control method, before obtaining the current speed and current torque of the engine, the method further includes:

[0011] Determining whether the water outlet temperature and torque of the engine are both lower than corresponding preset values;

[0012] If it is determined that the water outlet temperature and the torque of the engine are not lower than the corresponding preset values, executing the step of obtaining the current speed and current torque of the engine;

[0013] If it is determined that the water outlet temperature and the torque of the engine are both lower than corresponding preset values, the valve port opening value of the bypass valve is adjusted to 100%.

[0014] Optionally, in the above-mentioned control method of the EGR cooler bypass valve, after adjusting the valve port opening of the bypass valve to the valve port opening value, the method further includes:

[0015] Real-time acquisition of the current temperature of the exhaust gas output by the EGR cooler;

[0016] Determining the magnitude relationship between the current temperature and a preset temperature range;

[0017] If the current temperature is greater than the upper limit of the preset temperature range, the valve opening value of the bypass valve is reduced;

[0018] If the current temperature is lower than the lower limit of the preset temperature range, the valve opening value of the bypass valve is increased.

[0019] Optionally, in the above-mentioned EGR cooler bypass valve control method, determining the optimal temperature corresponding to the exhaust gas output by the EGR cooler based on the current speed and the current torque includes:

[0020] respectively determining a preset speed range corresponding to the current speed and a preset torque range corresponding to the current torque;

[0021] Calibration tests and simulation calculations are performed based on the preset speed range and the preset torque range to obtain an optimal temperature corresponding to the exhaust gas output by the EGR cooler.

[0022] Optionally, in the above-mentioned EGR cooler bypass valve control method, determining the valve opening value of the bypass valve in the EGR cooler based on the optimal temperature includes:

[0023] Determining a corresponding relationship between the exhaust gas temperature output from the EGR cooler and the valve opening of the bypass valve in the EGR cooler;

[0024] Based on the corresponding relationship, the valve opening value corresponding to the optimal temperature is determined.

[0025] A second aspect of the present application discloses an engine system, wherein a bypass valve of an EGR cooler in the engine system is arranged on a preset side of the EGR;

[0026] The ECU in the engine system is used to execute the control method of the EGR cooler bypass valve as disclosed in any one of the first aspects on the bypass valve.

[0027] Optionally, in the above engine system, the preset side is: the air path side of the EGR.

[0028] Optionally, in the above-mentioned engine system, the preset side is: the water channel side of the EGR.

[0029] Optionally, in the above engine system, the bypass valve is an electrically controlled bypass valve.

[0030] The control method for an EGR cooler bypass valve provided by the present invention is applied to an ECU in an engine system. The control method includes: obtaining a current engine speed and current torque; determining an optimal temperature corresponding to exhaust gas output from the EGR cooler based on the current speed and current torque; wherein the optimal temperature is the exhaust gas temperature corresponding to an optimal operating condition when the engine is operating at the current speed and current torque while meeting specific performance requirements; determining a valve opening value of a bypass valve in the EGR cooler based on the optimal temperature, and adjusting the valve opening of the bypass valve to the valve opening value. That is, the present application can determine the optimal temperature corresponding to exhaust gas output from the EGR cooler based on the current engine speed and current torque, and adjust the valve opening of the bypass valve to the valve opening value corresponding to the optimal temperature. This method not only achieves optimal engine performance and emissions while ensuring engine reliability, but also improves EGR efficiency by adjusting the valve opening of the bypass valve in the EGR cooler while meeting specific engine performance requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0032] Figure 1 A flow chart of a method for controlling an EGR cooler bypass valve provided in an embodiment of the present application;

[0033] Figure 2 A flow chart for determining an optimal temperature provided in an embodiment of the present application;

[0034] Figure 3 A flow chart for determining a valve opening value provided in an embodiment of the present application;

[0035] Figures 4 to 6 Flowchart of three EGR cooler bypass valve control methods provided in embodiments of the present application;

[0036] Figure 7 A schematic diagram of a partial structure of an engine system provided in an embodiment of the present application;

[0037] Figure 8 A schematic structural diagram of a variable flow electrically controlled bypass valve provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] This embodiment provides a control method for an EGR cooler bypass valve. Under the premise of meeting specific engine performance requirements, the EGR working efficiency is improved by adjusting the valve opening size of the bypass valve in the EGR cooler to achieve the optimal state of engine performance and emissions.

[0040] The control method of the EGR cooler bypass valve is generally applied to the ECU (Electronic Control Unit) in the engine system. Figure 1 , the control method may include the following steps:

[0041] S100: Obtain the current speed and torque of the engine.

[0042] The current speed of the engine is the current speed of the engine; and the current torque is the current torque of the engine.

[0043] In practical applications, the current operating parameters of the engine can be directly read to obtain the current rotation speed and current torque of the engine.

[0044] In addition, the current translation and current torque of the engine can also be obtained through other existing methods. This application does not specifically limit the method of obtaining the current translation and current torque of the engine, and all of them fall within the scope of protection of this application.

[0045] S102 : Determine an optimal temperature corresponding to exhaust gas output from the EGR cooler based on the current speed and the current torque.

[0046] The optimal temperature is the exhaust gas temperature corresponding to the optimal operating condition when the engine is running at the current speed and current torque while meeting specific performance requirements.

[0047] In practical applications, specific performance requirements of an engine may include: engine emission requirements, reliability requirements, and power requirements.

[0048] Specifically, the optimal operating condition may be the operating condition where the engine EGR working efficiency is optimal, or other operating conditions that can enable the engine to be in the optimal performance and emission state. This application does not make specific limitations on the optimal operating condition, and all of them fall within the scope of protection of this application.

[0049] In practical applications, the specific process of executing step S102 and determining the optimal temperature corresponding to the exhaust gas output by the EGR cooler based on the current speed and the current torque can be as follows: Figure 2 As shown, the following steps may be included:

[0050] S200: Determine a preset speed range corresponding to a current speed and a preset torque range corresponding to a current torque.

[0051] The preset speed range and the preset torque range are obtained by pre-dividing the engine's rotational speed and torque. The number of divisions in the preset rotational speed range and the preset torque range is generally the same. Specifically, the number of divisions in the preset rotational speed range and the preset torque range is N, where N is a positive integer greater than or equal to 2.

[0052] It should be noted that the specific value of N can be determined according to the specific application environment and user needs. This application does not make any specific limitations and all values ​​fall within the scope of protection of this application.

[0053] S202 : Perform calibration tests and simulation calculations based on a preset speed range and a preset torque range to obtain an optimal temperature corresponding to exhaust gas output from the EGR cooler.

[0054] In practical applications, the engine's universal performance (MAP) can be set to N preset translation ranges and torque ranges. Then, based on a combination of simulation calculations and test calibration, a comprehensive evaluation of reliability requirements, power requirements, economy requirements, and emission regulatory limit requirements is conducted to draw the optimal temperature corresponding to the exhaust gas output from the EGR cooler within each operating range.

[0055] It should be noted that in actual applications, the larger the value of N is, the higher the accuracy of the optimal temperature corresponding to the exhaust gas output of the EGR cooler obtained by calibration tests and simulation calculations based on the preset translation range and preset torque, and the larger the amount of calibration experiments and simulation calculations required.

[0056] S104 : Determine a valve opening value of a bypass valve in the EGR cooler based on the optimal temperature, and adjust the valve opening size of the bypass valve to the valve opening value.

[0057] In practical applications, the specific process of executing step S104, determining the valve opening value of the bypass valve in the EGR cooler according to the optimal temperature, and adjusting the valve opening size of the bypass valve to the valve opening value can be as follows: Figure 3 As shown, the following steps may be included:

[0058] S300: Determine a corresponding relationship between the exhaust gas temperature output from the EGR cooler and the opening of a bypass valve in the EGR cooler.

[0059] In actual applications, the correspondence between the exhaust gas temperature output by the EGR cooler and the valve port opening of the bypass valve in the EGR cooler can be pre-calibrated or obtained by simulation calculation based on the universal characteristics of the engine and the optimal temperature. The present application does not make any specific limitation on the correspondence between the exhaust gas temperature output by the EGR cooler and the valve port opening of the bypass valve in the EGR cooler, and all of them fall within the scope of protection of this application.

[0060] It should be noted that if the correspondence between the exhaust gas temperature output by the EGR cooler and the valve opening of the bypass valve in the EGR cooler is pre-calibrated, then within the area corresponding to each preset translation range and preset torque range in the engine universal characteristic (MAP), the optimal temperature and valve opening have a set value.

[0061] S302: Based on the corresponding relationship, determine the valve opening value corresponding to the optimal temperature.

[0062] In practical applications, the valve opening value corresponding to the optimal temperature can be found based on the correspondence between the exhaust gas temperature output by the EGR cooler and the valve opening of the bypass valve in the EGR cooler obtained in step S300.

[0063] Based on the above, this embodiment provides a control method for the EGR cooler bypass valve of the ECU that can be applied to the engine system. It can determine the optimal temperature corresponding to the exhaust gas output by the EGR cooler through the current speed and current torque of the engine, and adjust the valve opening of the bypass device to the valve opening value corresponding to the optimal temperature. It can not only achieve the optimal state of engine performance and emissions under the premise of ensuring engine reliability, but also improve the working efficiency of EGR by adjusting the valve opening size of the bypass valve in the EGR cooler while meeting the specific performance requirements of the engine.

[0064] Optionally, in another embodiment provided by the present application, before executing step S100 and obtaining the current speed and current torque of the engine, refer to Figure 4 , the control method of the EGR cooler bypass valve further includes:

[0065] S400: Determine whether the water outlet temperature and torque of the engine are both lower than corresponding preset values.

[0066] The engine water outlet temperature may be the coolant temperature at the point where the coolant enters the thermostat. The engine torque may be the torque value corresponding to the engine under the current operating conditions.

[0067] In actual applications, the water outlet temperature and torque of the engine are both lower than the corresponding preset values, indicating that the engine is operating in a low-load condition and the temperature in the engine cylinder is low.

[0068] Among them, the specific values ​​of the preset values ​​corresponding to the engine's water outlet temperature and the preset values ​​corresponding to the torque can be determined according to the specific application environment and user needs. This application does not make specific restrictions. It only needs to ensure that when the engine's water outlet temperature and torque are lower than the corresponding preset values, the engine is in a low-load operating state.

[0069] If it is determined that the water outlet temperature and the torque of the engine are not lower than the corresponding preset values, the step of obtaining the current speed and current torque of the engine is executed, that is, step S100 is executed.

[0070] In actual applications, if it is determined that at least one of the engine's water outlet temperature and torque is not lower than the corresponding preset value, it can be regarded as determined that the engine's water outlet temperature and torque are not both lower than the corresponding preset value, indicating that the engine is most likely not in a low-load power operation state, and the temperature in the engine cylinder is relatively high. It is necessary to determine the optimal temperature corresponding to the exhaust gas output by the EGR cooler based on the current speed and current torque of the engine obtained in real time, and then control the valve opening size of the bypass valve to the valve opening value corresponding to the optimal temperature, so as to achieve the optimal state of engine performance and emissions while ensuring engine reliability. It is also possible to improve the working efficiency of EGR by adjusting the valve opening size of the bypass valve in the EGR cooler while meeting the specific performance requirements of the engine.

[0071] If it is determined that the water outlet temperature and the torque of the engine are both lower than the corresponding preset values, step S402 is executed.

[0072] S402: Adjust the valve opening value of the bypass valve to 100%.

[0073] In actual applications, if it is determined that the water outlet temperature and torque of the engine are both lower than the corresponding preset values, it means that the engine is in a low-load power operation state, the temperature in the engine cylinder is low, and the exhaust gas output by the EGR cooler is also low, so no cooling is required. The valve opening value of the cooler bypass valve can be adjusted to 100%, that is, the valve port of the bypass valve is adjusted to a fully open state.

[0074] Optionally, in another embodiment provided in the present application, after the valve opening of the bypass valve is adjusted to the valve opening value in step S104, refer to Figure 5 , the control method of the EGR cooler bypass valve further includes:

[0075] S500: Acquire the current temperature of the exhaust gas output by the EGR cooler in real time.

[0076] In actual applications, the current temperature of the exhaust gas output by the EGR cooler can be obtained through a temperature sensor arranged at the exhaust gas output port of the EGR cooler; in addition, the current temperature of the exhaust gas output by the EGR cooler can also be obtained through other existing methods. This application does not specifically limit the specific method of obtaining the current temperature of the exhaust gas output by the EGR cooler, and all of them fall within the scope of protection of this application.

[0077] S502: Determine the relationship between the current temperature and the preset temperature range.

[0078] If the current temperature is greater than the upper limit of the preset temperature range, step S504 is executed; if the current temperature is less than the lower limit of the preset temperature range, step S506 is executed.

[0079] S504: Reduce the valve opening value of the bypass valve.

[0080] In actual applications, if the current temperature is greater than the upper limit of the preset temperature range, it means that the output exhaust gas temperature is too high, which will cause the engine's emissions and performance to deteriorate and fail to meet emission requirements. The valve opening value of the bypass valve needs to be reduced to lower the output exhaust gas temperature.

[0081] It should be noted that after executing step S504 and reducing the valve opening value of the bypass valve, it is possible to return to execute real-time acquisition of the current temperature of the exhaust gas output by the EGR cooler, that is, step S500, and re-judge the relationship between the adjusted current temperature and the preset temperature range until it is determined that the current temperature is within the preset temperature range. In this way, the exhaust gas output temperature of the EGR cooler can be fully controlled, and the optimal state of engine performance and emissions can be achieved while ensuring engine reliability.

[0082] S506: Increase the valve opening value of the bypass valve.

[0083] In actual applications, if the current temperature is lower than the upper limit of the preset temperature range, it means that the output exhaust gas temperature is too low. The corrosive substances in the exhaust gas may cause carbon deposition, coking and other faults in the EGR cooler, resulting in blockage of the EGR cooler and valve jamming, resulting in reduced cooling efficiency. It is necessary to increase the valve opening value of the bypass valve to increase the output exhaust gas temperature.

[0084] It should be noted that after executing step S506 and increasing the valve opening value of the bypass valve, it is also possible to return to execute real-time acquisition of the current temperature of the exhaust gas output by the EGR cooler, that is, step S500, and re-judge the relationship between the adjusted current temperature and the preset temperature range until it is determined that the current temperature is within the preset temperature range. In this way, the exhaust gas output temperature of the EGR cooler can be fully controlled, and the optimal state of engine performance and emissions can be achieved while ensuring engine reliability.

[0085] It should be noted that the specific values ​​of the upper limit and lower limit of the preset temperature range can be determined according to the specific application environment and user needs. This application does not make specific limitations and all fall within the scope of protection of this application.

[0086] It should also be noted that in actual application, after executing step S500 and obtaining the current temperature of the exhaust gas output by the EGR cooler in real time, Figure 6As shown, it is also possible to first determine whether the current temperature is lower than the upper limit of the preset temperature range, that is, to execute step S600; if the determination result is no, the valve opening value of the bypass valve is reduced, that is, to execute step S602, and then return to the step of obtaining the current temperature of the exhaust gas output by the EGR cooler in real time; if the determination result is yes, then determine whether the current temperature is greater than the lower limit of the preset temperature range, that is, to execute step S604; if the determination result is no, the valve opening value of the bypass valve is increased, that is, to execute step S606, and then return to the step of obtaining the current temperature of the exhaust gas output by the EGR cooler in real time, which can also achieve full controllability of the exhaust gas output by the EGR cooler, and achieve the optimal state of engine performance and emissions while ensuring engine reliability; if the determination result is yes, it means that the current temperature is between the upper limit and the lower limit of the preset temperature range, and there is no need to adjust the valve opening of the bypass valve.

[0087] In actual application, Figure 6 As shown, after executing step S400 and adjusting the valve opening value of the bypass valve to 100%, step S500 can be executed to obtain the current temperature of the exhaust gas output by the EGR cooler in real time, thereby further achieving full controllability of the exhaust gas output by the EGR cooler. Under the premise of ensuring engine reliability, the optimal state of engine performance and emissions can be achieved.

[0088] In combination with the above, another embodiment of the present application further provides an engine system, in which a bypass valve of an EGR cooler is arranged on a preset side of the EGR.

[0089] Among them, the engine system can be a diesel engine system or a gasoline engine system, which can be determined according to the specific application environment and user needs, and both fall within the scope of protection of this application.

[0090] The ECU in the engine system is used to execute the control method of the EGR cooler bypass valve as described in any of the above embodiments on the bypass valve.

[0091] In practical applications, the bypass valve of the EGR cooler can be set on the water side of the EGR (i.e. Figure 7 As shown), it can also be set on the gas path side of EGR (not shown in the figure), depending on the specific application environment and user needs. This application does not make specific limitations and all belong to the protection scope of this application.

[0092] It should be noted that the bypass valve can be an electrically controlled bypass valve. Specifically, it can be a variable flow electrically controlled bypass valve, that is, Figure 8As shown. In actual applications, the engine ECU can send a control signal to control the valve opening of the bypass valve. Specifically, the valve opening of the bypass valve can be controlled by the voltage of the control signal. Specifically, the larger the voltage of the control signal, the smaller the valve opening, and the smaller the voltage, the larger the valve opening. Of course, it is also possible that the larger the voltage, the larger the valve opening, and the smaller the voltage, the smaller the valve opening. This can be determined based on the specific application environment and user needs, and all fall within the scope of protection of this application.

[0093] It should also be noted that for the relevant description of the control method of the EGR cooler bypass valve, please refer to Figures 1 to 6 The corresponding embodiments will not be described in detail here.

[0094] Similarly, for relevant descriptions of the engine system, please refer to the prior art, and this application will not go into details, as all of them fall within the scope of protection of this application.

[0095] It is worth noting that the existing EGR cooler bypass valve mainly relies on the suction of the vacuum pump to provide power, and controls the bypass valve to be in the open or closed state. It is impossible to achieve gradual controllable opening of the bypass valve port, and it is impossible to accurately control the exhaust gas temperature output by the EGR cooler, and it is impossible to take into account both the reliability and performance of the engine. The bypass valve provided in the present application can be an electronically controlled bypass valve, which can make the exhaust gas temperature output by the EGR cooler controllable through the control method of the EGR cooler bypass valve, and can effectively avoid the exhaust gas temperature after EGR cooling being too low, which is beneficial to reducing the risk of carbon deposits, coking, EGR valve sticking and other failures of the EGR cooler, thereby ensuring the reliability of the engine, and making the exhaust gas temperature after the engine EGR cooler controllable, which can effectively avoid the exhaust gas temperature after EGR cooling being too high, and effectively prevent the engine's emissions and performance from deteriorating, and failing to meet emission requirements.

[0096] The features described in the various embodiments of this specification can be replaced or combined with each other. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple. For relevant parts, refer to the partial description of the method embodiment. The system and system embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without expending creative work.

[0097] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0098] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

[0099] It should also be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

Claims

1. A method for controlling an EGR cooler bypass valve, characterized in that: The control method for an ECU used in an engine system includes: Get the current speed and current torque of the engine; determining an optimal temperature corresponding to exhaust gas output by the EGR cooler based on the current speed and the current torque; wherein the optimal temperature is the exhaust gas temperature corresponding to an optimal operating condition when the engine is running at the current speed and the current torque while meeting specific performance requirements, the specific performance requirements including: emission requirements, reliability requirements, and power requirements of the engine; the optimal operating condition is an operating condition where the EGR working efficiency of the engine is optimal, or an operating condition where the engine is in optimal performance and emission conditions; determining a valve opening value of the bypass valve in the EGR cooler based on the optimal temperature, and adjusting the valve opening size of the bypass valve to the valve opening value; The current temperature of the exhaust gas output by the EGR cooler is obtained in real time. If the current temperature deviates from a preset temperature range, the valve opening value of the bypass valve is dynamically adjusted according to the degree of deviation until the current temperature returns to the preset temperature range.

2. The control method of the EGR cooler bypass valve according to claim 1, characterized in that: Before obtaining the current speed and current torque of the engine, it also includes: Determining whether the water outlet temperature and torque of the engine are both lower than corresponding preset values; If it is determined that the water outlet temperature and the torque of the engine are not lower than the corresponding preset values, executing the step of obtaining the current speed and current torque of the engine; If it is determined that the water outlet temperature and the torque of the engine are both lower than corresponding preset values, the valve port opening value of the bypass valve is adjusted to 100%.

3. The control method of the EGR cooler bypass valve according to claim 1, characterized in that: After adjusting the valve port opening of the bypass valve to the valve port opening value, the method further includes: Real-time acquisition of the current temperature of the exhaust gas output by the EGR cooler; Determining the magnitude relationship between the current temperature and a preset temperature range; If the current temperature is greater than the upper limit of the preset temperature range, the valve opening value of the bypass valve is reduced; If the current temperature is lower than the lower limit of the preset temperature range, the valve opening value of the bypass valve is increased.

4. The control method of the EGR cooler bypass valve according to claim 1, characterized in that: Determining an optimal temperature corresponding to exhaust gas output by the EGR cooler based on the current speed and the current torque includes: respectively determining a preset speed range corresponding to the current speed and a preset torque range corresponding to the current torque; Calibration tests and simulation calculations are performed based on the preset speed range and the preset torque range to obtain an optimal temperature corresponding to the exhaust gas output by the EGR cooler.

5. The control method of the EGR cooler bypass valve according to claim 1, characterized in that: Determining a valve opening value of the bypass valve in the EGR cooler based on the optimal temperature includes: Determining a corresponding relationship between the exhaust gas temperature output from the EGR cooler and the valve opening of the bypass valve in the EGR cooler; Based on the corresponding relationship, the valve opening value corresponding to the optimal temperature is determined.

6. An engine system, characterized in that: The bypass valve of the EGR cooler in the engine system is arranged on a preset side of the EGR; The ECU in the engine system is configured to execute the EGR cooler bypass valve control method according to any one of claims 1 to 5 on the bypass valve.

7. The engine system according to claim 6, characterized in that The preset side is: the gas path side of the EGR.

8. The engine system according to claim 6, wherein: The preset side is: the water channel side of the EGR.

9. The engine system according to any one of claims 6 to 8, characterized in that: The bypass valve is an electrically controlled bypass valve.

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