EGR system, control method and vehicle

Abstract

The invention provides an EGR system, a control method and a vehicle. The EGR system comprises an engine module and an EGR system pressurization module, the engine module comprises an engine body, an engine ECU, an air inlet mechanism and an exhaust mechanism, the input end of the EGR system pressurization module is connected with the exhaust mechanism, and the output end of the EGR system pressurization module is connected with the air inlet mechanism; the EGR system supercharging module comprises an EGR controller and an electric gas compressor, the electric gas compressor and the engine ECU are both connected with the EGR controller, and the EGR controller adjusts the working state of the electric gas compressor according to parameters in the EGR system supercharging module and engine operation parameters provided by the engine ECU so as to control the EGR flow. According to the EGR system, the problems that in the prior art, high EGR rate and global range adjustment cannot be achieved at the same time, dynamic response is slow, control precision is low, the system is complex, cost is high, and reliability is poor can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of engine EGR, and particularly to an EGR system, a control method and a vehicle. Background Art

[0002] EGR (Exhaust Gas Recirculation) technology is an emission reduction technology widely used in internal combustion engines. The core principle is to introduce a part of the combustion exhaust gas of the internal combustion engine into the intake circuit, mix it with fresh air and then participate in combustion, achieving the effects of reducing combustion temperature, reducing the generation amount of nitrogen oxides and anti-knock.

[0003] With the increasingly strict regulations on vehicle emission reduction, especially the requirement to control nitrogen oxide emissions, the application range of EGR technology and the EGR rate when using EGR technology are gradually increasing. A higher EGR rate requires the system to have higher precision and response speed to meet the needs of different working conditions. However, the existing EGR technology has relatively large problems in aspects such as working range and rapid response.

[0004] The existing EGR technical routes are divided into high-pressure EGR and low-pressure EGR. The high-pressure EGR technology takes gas before the turbine, mixes it with the supercharged fresh air and enters the intake manifold. This technology requires a certain pressure difference between the exhaust gas in the exhaust manifold and the mixture gas in the intake manifold to supply the EGR gas. In natural gas heavy trucks, this pressure difference is often greater than 20 kPa, and there are relatively large pumping losses in the engine. This will result in the following adverse situations: (1) To improve the engine economy and the efficiency of the turbocharger, the pressure in the intake manifold is made higher than that in the exhaust manifold, and the intake and exhaust processes do positive work on the piston; this is contrary to the original intention of increasing the intake and exhaust pressure difference to increase the EGR rate. In actual development, a turbocharger with extremely low efficiency is often used, which limits the improvement of the engine thermal efficiency. (2) To achieve high EGR, it is necessary to increase the exhaust side pressure, which is extremely unfavorable to the reliability of the exhaust side and increases the risk of exhaust manifold cracking and seal failure. (3) In actual development, for the existing high-pressure EGR system, it is necessary to conduct matching design of the engine, the EGR system and the turbocharger within the full Map of the vehicle engine. Due to the need to take into account all working conditions, the EGR rate in the common area of the engine is insufficient, and the engine knocking risk is high. To reduce the knocking risk, it is often necessary to reduce the engine compression ratio, which also limits the improvement of the engine thermal efficiency. At the same time, on the premise of taking into account all working conditions, in order to ensure the EGR rate in the common area as much as possible, a throttle valve is needed to reduce the pressure of the mixture gas in the intake manifold through throttling, resulting in a relatively large resistance in the intake system, which further limits the improvement of the engine thermal efficiency.

[0005] The low-pressure EGR technology takes in gas after the turbine or after the post-processor, and leads it to before the compressor through pipelines to achieve EGR supply. Although this can meet the EGR rate requirements within the entire engine Map, the system is complex, has a high risk of reliability, and the cost is nearly ten thousand yuan higher than that of the high-pressure EGR technology route. At the same time, introducing the EGR gas before the compressor will interfere with the flow before the compressor and increase the temperature of the gas before the compressor, which will lead to a decrease in the compressor efficiency, induce early surge of the compressor, cause deterioration of the system performance, and even the risk of functional failure. Summary of the Invention

[0006] An embodiment of the present invention provides an EGR system, a control method, and a vehicle. This EGR system can overcome the problems existing in the prior art, such as the inability to simultaneously achieve a high EGR rate, global range adjustment, slow dynamic response, low control accuracy, complex system, high cost, and poor reliability of EGR.

[0007] According to one aspect of the present invention, an EGR system is provided, including an engine module and an EGR system supercharging module. The engine module includes an engine body, an engine ECU, an intake mechanism, and an exhaust mechanism. The input end of the EGR system supercharging module is connected to the exhaust mechanism, and the output end of the EGR system supercharging module is connected to the intake mechanism;

[0008] The EGR system supercharging module includes an EGR controller and an electric compressor. Both the electric compressor and the engine ECU are connected to the EGR controller. The EGR controller is used to adjust the working state of the electric compressor according to the parameters in the EGR system supercharging module and the engine operation parameters provided by the engine ECU to control the EGR flow rate.

[0009] Optionally, the EGR system supercharging module further includes a drive motor, an electronically controlled three-way valve, a first pressure sensor, a second pressure sensor, a first temperature sensor, and a second temperature sensor;

[0010] The control terminal of the drive motor, the control terminal of the electronic control three-way valve, the first pressure sensor, the second pressure sensor, the first temperature sensor, and the second temperature sensor are all connected to the EGR controller. The drive motor is used to drive the operation of the electric supercharger. The input end of the electric supercharger is connected to the exhaust manifold of the exhaust mechanism, and the output end of the electric supercharger is connected to the input end of the electronic control three-way valve. The first output end of the electronic control three-way valve is connected to the intake mechanism, and the second output end of the electronic control three-way valve is connected to the input end of the electric supercharger. The first pressure sensor and the first temperature sensor are arranged at the input end of the electric supercharger, the second pressure sensor is arranged at the output end of the electric supercharger, and the second temperature sensor is arranged at the first output end of the electronic control three-way valve.

[0011] Optionally, a first EGR cooler is further included. The EGR system boosting module further includes a second EGR cooler, a first coolant flow control valve, and a second coolant flow control valve. The control terminals of the first coolant flow control valve and the second coolant flow control valve are both connected to the EGR controller. The input end of the electric supercharger is connected to the exhaust manifold of the exhaust mechanism through the first EGR cooler, and the first output end of the electronic control three-way valve is connected to the intake mechanism through the second EGR cooler. The second temperature sensor is arranged at the output end of the second EGR cooler. The input end of the first coolant flow control valve is connected to the engine cooling circuit, and the coolant returns to the engine cooling circuit after passing through the first EGR cooler; the input end of the second coolant flow control valve is connected to the engine cooling circuit, and the coolant returns to the engine cooling circuit after passing through the second EGR cooler.

[0012] Optionally, the EGR system boosting module further includes a drive motor, a first switching valve, a second switching valve, a first pressure sensor, a second pressure sensor, a first temperature sensor, and a second temperature sensor;

[0013] The control terminal of the drive motor, the control terminal of the first switching valve, the control terminal of the second switching valve, the first pressure sensor, the second pressure sensor, the first temperature sensor, and the second temperature sensor are all connected to the EGR controller. The drive motor is used to drive the operation of the electric supercharger. The input end of the electric supercharger is connected to the exhaust manifold of the exhaust mechanism. The input ends of the first switching valve and the second switching valve are both connected to the output end of the electric supercharger. The output end of the first switching valve is connected to the intake mechanism. The output end of the second switching valve is connected to the input end of the electric supercharger. The first pressure sensor and the first temperature sensor are arranged at the input end of the electric supercharger. The second pressure sensor is arranged at the output end of the electric supercharger. The second temperature sensor is arranged at the output end of the first switching valve.

[0014] Optionally, it further includes a first EGR cooler. The EGR system boosting module further includes a second EGR cooler, a first coolant flow control valve, and a second coolant flow control valve. The control terminals of the first coolant flow control valve and the second coolant flow control valve are both connected to the EGR controller. The input end of the electric supercharger is connected to the exhaust manifold of the exhaust mechanism through the first EGR cooler. The output end of the first switching valve is connected to the intake mechanism through the second EGR cooler. The second temperature sensor is arranged at the output end of the second EGR cooler. The input end of the first coolant flow control valve is connected to the engine cooling circuit, and the coolant returns to the engine cooling circuit after passing through the first EGR cooler; the input end of the second coolant flow control valve is connected to the engine cooling circuit, and the coolant returns to the engine cooling circuit after passing through the second EGR cooler.

[0015] Optionally, the intake mechanism includes an air filter, an intercooler, a throttle valve, a mixer, and an intake manifold. The output end of the air filter is connected to the input end of the intercooler. The output end of the intercooler is connected to the first input end of the mixer. The output end of the second EGR cooler is connected to the second input end of the mixer. The output end of the mixer is connected to the intake manifold. The throttle valve is arranged between the intercooler and the mixer;

[0016] The exhaust mechanism includes an exhaust manifold and a post-processor. The first output end of the exhaust manifold is connected to the input end of the electric supercharger. The second output end of the exhaust manifold is connected to the input end of the post-processor.

[0017] Optionally, the engine module further includes an exhaust gas turbocharging mechanism, which includes a compressor and a turbine. The compressor is disposed between the air filter and the intercooler, and the turbine is disposed between the exhaust manifold and the aftertreatment device. The turbine drives the compressor to rotate through a rotating shaft, and the compressor pressurizes the air filtered by the air filter.

[0018] According to another aspect of the present invention, a control method for an EGR system is provided, which is applicable to the above EGR system. The control method includes:

[0019] Obtaining parameters in the EGR system boosting module and engine operating parameters provided by the engine ECU;

[0020] Determining the operating state of the engine according to the engine operating parameters. When the engine is in a non-shutdown state, adjusting the operating state of the electric compressor according to the parameters in the EGR system boosting module and the engine operating parameters provided by the engine ECU to control the EGR flow rate.

[0021] Optionally, the EGR system boosting module includes a drive motor, a first pressure sensor, a second pressure sensor, a first temperature sensor, and a second temperature sensor. Obtaining parameters in the EGR system boosting module and engine operating parameters provided by the engine ECU includes:

[0022] Obtaining signals collected by the first pressure sensor, the second pressure sensor, the first temperature sensor, the second temperature sensor, the current speed of the drive motor, and the throttle pedal position, engine speed, intake air flow rate, intake manifold pressure sensor signal, and target EGR flow rate issued by the engine ECU.

[0023] Optionally, after obtaining parameters in the EGR system boosting module and engine operating parameters provided by the engine ECU, it further includes:

[0024] Calculating the target boost pressure of the electric compressor according to the intake manifold pressure sensor signal in combination with the calibration Map of the flow rate and pressure loss of the pipeline between the electric compressor and the intake manifold;

[0025] Calculating the target speed of the drive motor according to the target EGR flow rate, the pressure of the first pressure sensor, the target boost pressure, the temperature of the first temperature sensor, and the gas flow equation of the gas flowing through the electric compressor, and adjusting the current speed of the drive motor to the target speed;

[0026] Calculate the actual EGR flow rate according to the pressure of the first pressure sensor, the pressure of the second pressure sensor, the temperature of the first temperature sensor, and the gas flow equation of the electric compressor.

[0027] Optionally, when the engine is in a non-shutdown state, adjust the operating state of the electric compressor according to the parameters in the EGR system supercharging module and the engine operating parameters provided by the engine ECU to control the EGR flow rate, including:

[0028] When the engine is in a non-shutdown state, obtain the magnitude of the target EGR flow rate;

[0029] When the target EGR flow rate is 0, control the gas at the output end of the electric compressor to return to the input end of the electric compressor, and at the same time control the speed of the drive motor to the idling state and maintain the self-circulation mode of the electric compressor;

[0030] When the target EGR flow rate is not 0, control the gas at the output end of the electric compressor to be transmitted to the intake mechanism, compare the actual EGR flow rate with the target EGR flow rate, when the actual EGR flow rate is equal to the target EGR flow rate, keep the speed of the drive motor, and when the actual EGR flow rate is not equal to the target EGR flow rate, adjust the speed of the drive motor until the actual EGR flow rate is equal to the target EGR flow rate.

[0031] Optionally, the EGR system supercharging module includes an electronically controlled three-way valve. When the target EGR flow rate is 0, the electronically controlled three-way valve switches to the second channel, so that the gas at the output end of the electric compressor returns to the input end of the electric compressor; when the target EGR flow rate is not 0, the electronically controlled three-way valve switches to the first channel, so that the gas at the output end of the electric compressor is transmitted to the intake mechanism.

[0032] Optionally, the EGR system supercharging module includes a first switching valve and a second switching valve. When the target EGR flow rate is 0, the first switching valve is closed and the second switching valve is opened, so that the gas at the output end of the electric compressor returns to the input end of the electric compressor; when the target EGR flow rate is not 0, the first switching valve is opened and the second switching valve is closed, so that the gas at the output end of the electric compressor is transmitted to the intake mechanism.

[0033] Optionally, the EGR system further includes a first EGR cooler, and the EGR system supercharging module further includes a second EGR cooler, a first coolant flow control valve, and a second coolant flow control valve; the control method further includes:

[0034] When the engine is operating or the ambient temperature is higher than the first preset temperature, the EGR controller controls the opening degree of the first coolant flow control valve so that the temperature of the first temperature sensor is greater than the second preset temperature;

[0035] When the temperature of the first temperature sensor is greater than or equal to the second preset temperature, the EGR controller controls to maintain the current opening degree of the first coolant flow control valve; when the temperature of the first temperature sensor is less than the second preset temperature, the EGR controller controls to adjust the opening degree of the first coolant flow control valve until the temperature of the first temperature sensor is greater than or equal to the second preset temperature, and at the same time controls the second coolant flow control valve to be fully open;

[0036] When the engine is in a shutdown state and the ambient temperature is lower than the first preset temperature, the EGR controller controls the opening degrees of the first coolant flow control valve and the second coolant flow control valve so that the temperature of the first temperature sensor is greater than or equal to the second preset temperature, and the temperature of the second temperature sensor is greater than or equal to the third preset temperature, and shuts down after maintaining operation for a preset time;

[0037] When the temperature of the first temperature sensor is greater than or equal to the second preset temperature and the temperature of the second temperature sensor is greater than or equal to the third preset temperature, the EGR controller controls to maintain the current opening degrees of the first coolant flow control valve and the second coolant flow control valve; when the temperature of the first temperature sensor is less than the second preset temperature and the temperature of the second temperature sensor is less than the third preset temperature, the EGR controller controls to adjust the opening degrees of the first coolant flow control valve and the second coolant flow control valve until the temperature of the first temperature sensor is greater than or equal to the second preset temperature and the temperature of the second temperature sensor is greater than or equal to the third preset temperature;

[0038] Wherein, the second preset temperature is greater than the third preset temperature, and the third preset temperature is greater than the first preset temperature.

[0039] According to another aspect of the present invention, a vehicle is provided, including the above-mentioned EGR system.

[0040] The EGR system provided by the embodiment of the present invention includes an engine module and an EGR system supercharging module. The engine module includes an engine body, an engine ECU, an intake mechanism, and an exhaust mechanism. The EGR system supercharging module includes an EGR controller and an electric supercharger. The input end of the EGR system supercharging module is connected to the exhaust mechanism, and the output end of the EGR system supercharging module is connected to the intake mechanism. The EGR system supercharging module introduces part of the exhaust gas discharged by the exhaust mechanism into the intake mechanism to achieve EGR. Both the electric supercharger and the engine ECU are connected to the EGR controller. The working state of the electric supercharger is adjusted by the EGR controller according to the parameters in the EGR system supercharging module and the engine operation parameters provided by the engine ECU to control the EGR flow rate. Compared with the prior art, the EGR system provided by the embodiment of the present invention simplifies the layout of the EGR system and is beneficial to reducing the system cost. By adopting the EGR system supercharging module, automatic calculation and precise control of the EGR flow rate are achieved. Compared with the low-pressure EGR system, the venturi tube, check valve, and electric EGR valve are eliminated. The structure of this patent solution is simpler and is beneficial to reducing the system cost. By using an electric supercharger, independent control of the EGR flow rate can be achieved, decoupling the EGR flow rate from the intake control, which is beneficial to achieving high EGR rate control under all Map working conditions of the engine. Compared with traditional natural gas engines, in order to take into account all working conditions of the engine and avoid problems such as insufficient EGR rate and high knock risk in common working conditions, methods such as reducing the EGR rate, using low-performance superchargers, and throttle throttling are adopted. By adopting this solution, a high-efficiency supercharger can be matched to increase the intake pressure, which is beneficial to improving the economy, power performance, and reliability of the engine.

[0041] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. Brief Description of the Drawings

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0043] Figure 1 It is a schematic structural diagram of an EGR system provided by an embodiment of the present invention;

[0044] Figure 2 It is a schematic structural diagram of another EGR system provided by an embodiment of the present invention;

[0045] Figure 3 It is a schematic flow diagram of a control method for an EGR system provided by an embodiment of the present invention;

[0046] Figure 4 It is a schematic flowchart of another EGR control method provided by an embodiment of the present invention. Detailed implementation manners

[0047] In order to enable those skilled in the art of the present technology to better understand this solution, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0048] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily need to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0049] Figure 1 It is a schematic structural diagram of an EGR system provided by an embodiment of the present invention. Refer to Figure 1 , the EGR system includes an engine module 20 and an EGR system supercharging module 4. The engine module 20 includes an engine body 1, an engine ECU 13, an intake mechanism and an exhaust mechanism. The intake mechanism includes an intake manifold 12, and the exhaust mechanism includes an exhaust manifold 2. The input end of the EGR system supercharging module 4 is connected to the exhaust mechanism (an output end of the exhaust manifold 2), and the output end of the EGR system supercharging module 4 is connected to the intake mechanism (an input end of the intake manifold 12); the EGR system supercharging module 4 includes an EGR controller 401 and an electric supercharger 407. Both the electric supercharger 407 and the engine ECU 13 are connected to the EGR controller 401. The EGR controller 401 is used to adjust the working state of the electric supercharger 407 according to the parameters in the EGR system supercharging module 4 and the engine operation parameters provided by the engine ECU 13 to control the EGR flow rate.

[0050] Among them, the engine module 20 in the EGR system can be a natural gas engine. Fresh air enters the engine body 1 from the intake mechanism. The engine body 1 is used to burn natural gas to do work and discharge exhaust gas from the exhaust mechanism. The engine body 1 includes a plurality of cylinders. Figure 1 Figure 1 schematically shows that the engine body 1 includes 6 cylinders, which is not a limitation to the present invention. The engine ECU 13, namely the Electronic Control Unit, can also be called the "vehicle computer", and it is the most important part that determines the performance of the whole vehicle. As one of the core components of modern automotive electronics, there may be multiple ECUs in a vehicle, each managing different functions; and there is information exchange between each ECU. Although the control system on the whole vehicle is becoming more and more complex, it still must have the most basic structure - a microprocessor (CPU), a memory (ROM, RAM), an input / output interface (I / O), an analog-to-digital converter (AD), and large-scale integrated circuits such as shaping and driving. The engine ECU 13 is used to control the operation of the engine and collect various operating parameters during the operation of the engine. An electric compressor 407 is provided in the EGR system supercharging module 4 to achieve the EGR function. The EGR controller 401 adjusts the electric compressor 407 to output different pressures according to the parameters in the EGR system supercharging module 4 and the engine operating parameters provided by the engine ECU 13, so as to control the EGR flow rate. The specific control method can refer to the following embodiments.

[0051] Compared with the prior art, the EGR system provided by the embodiments of the present invention simplifies the layout of the EGR system, which is beneficial to reducing the system cost. By adopting the EGR system supercharging module, automatic calculation and precise control of the EGR flow rate are achieved. Compared with the low-pressure EGR system, the venturi tube, the check valve, and the electric EGR valve are eliminated. The structure of the present patent solution is simpler, which is beneficial to reducing the system cost. By using an electric compressor, independent control of the EGR flow rate can be achieved, decoupling the EGR flow rate from the intake control, which is beneficial to achieving high EGR rate control under the full Map operating conditions of the engine. Compared with traditional natural gas engines, in order to take into account all operating conditions of the engine and avoid problems such as insufficient EGR rate and high knock risk in common operating conditions, methods such as reducing the EGR rate, using a low-performance supercharger, and throttling the throttle valve are adopted. By using the present solution, a high-efficiency supercharger can be matched to increase the intake pressure, which is beneficial to improving the economy, power performance, and reliability of the engine.

[0052] Continue to refer to Figure 1, Optionally, the EGR system supercharging module 4 further includes a drive motor 406, an electronically controlled three-way valve 408, a first pressure sensor 404, a second pressure sensor 405, a first temperature sensor 403, and a second temperature sensor 410; the control terminal of the drive motor 406, the control terminal of the electronically controlled three-way valve 408, the first pressure sensor 404, the second pressure sensor 405, the first temperature sensor 403, and the second temperature sensor 410 are all connected to the EGR controller 401. The drive motor 406 is used to drive the electric compressor 407 to operate. The input end of the electric compressor 407 is connected to the exhaust manifold 2 of the exhaust mechanism, and the output end of the electric compressor 407 is connected to the input end of the electronically controlled three-way valve 408. The first output end of the electronically controlled three-way valve 408 is connected to the intake mechanism, and the second output end of the electronically controlled three-way valve 408 is connected to the input end of the electric compressor 407. The first pressure sensor 404 and the first temperature sensor 403 are arranged at the input end of the electric compressor 407, the second pressure sensor 405 is arranged at the output end of the electric compressor 407, and the second temperature sensor 403 is arranged at the first output end of the electronically controlled three-way valve 408.

[0053] Among them, the first pressure sensor 404 is used to measure the pressure at the input end of the electric compressor 407 and transmit it to the EGR controller 401. The second pressure sensor 405 is used to measure the pressure at the output end of the electric compressor 407 and transmit it to the EGR controller 401. The first temperature sensor 403 is used to measure the temperature at the input end of the electric compressor 407 (the exhaust gas temperature before EGR) and transmit it to the EGR controller 401. The second temperature sensor 410 is used to measure the temperature at the first output end of the electronically controlled three-way valve 408 (the gas temperature when EGR enters the intake mechanism) and transmit it to the EGR controller 401. The drive motor 406 can be a high-speed DC motor, which has the functions of a motor (maintaining speed or accelerating) and a generator (decelerating). Adjusting the speed of the drive motor 406 can adjust the pressure at the output end of the electric compressor 407, realizing the supercharging of the EGR system supercharging module 4. The electronically controlled three-way valve 408 includes one input end and two output ends, where the input end is connected to the output end of the electric compressor 407, the first output end is connected to the intake mechanism, and the second output end is connected to the input end of the electric compressor 407, thus forming two channels. When EGR is required, the gas output by the electric compressor 407 is transmitted to the intake mechanism through the electronically controlled three-way valve 408. When EGR is not required, the gas output by the electric compressor 407 returns to the input end of the electric compressor 407 through the electronically controlled three-way valve 408.

[0054] Continue to refer to Figure 1, Optionally, the EGR system further includes a first EGR cooler 3. The EGR system supercharging module 4 further includes a second EGR cooler 409, a first coolant flow control valve 402, and a second coolant flow control valve 411. The control ends of the first coolant flow control valve 402 and the second coolant flow control valve 411 are both connected to the EGR controller 401. The input end of the electric supercharger 407 is connected to the exhaust manifold 2 of the exhaust mechanism through the first EGR cooler 3. The first output end of the electronically controlled three-way valve 408 is connected to the intake mechanism through the second EGR cooler 409. The second temperature sensor 410 is disposed at the output end of the second EGR cooler 409. The input end of the first coolant flow control valve 402 is connected to the engine cooling circuit, and the coolant returns to the engine cooling circuit after passing through the first EGR cooler 3; the input end of the second coolant flow control valve 411 is connected to the engine cooling circuit, and the coolant returns to the engine cooling circuit after passing through the second EGR cooler 409.

[0055] Among them, the first EGR cooler 3 is used to control the temperature of the exhaust gas input into the electric supercharger 407. The first EGR cooler 3 is connected to the engine cooling circuit through the first coolant flow control valve 402. When the opening degree of the first coolant flow control valve 402 changes, the coolant flow rate passing through the first EGR cooler 3 is different, and the different cooling capacities of the first EGR cooler 3 can be adjusted. The second EGR cooler 409 is used to adjust the temperature of the gas entering the intake mechanism through EGR. The second EGR cooler 409 is connected to the engine cooling circuit through the second coolant flow control valve 411. When the opening degree of the second coolant flow control valve 411 changes, the coolant flow rate passing through the second EGR cooler 409 is different, and the different cooling capacities of the second EGR cooler 409 can be adjusted. The opening degrees of the first coolant flow control valve 402 and the second coolant flow control valve 411 are controlled by the EGR controller 401.

[0056] The EGR system provided by the embodiment of the present invention uses the EGR system supercharging module, which is beneficial to improving the reliability, EGR responsiveness, and control accuracy of the electric supercharger assembly. By using an electronically controlled three-way valve to switch the air flow channel and a high-speed DC motor with the functions of a motor and a generator, it can ensure that the drive motor never stops during the operation of the engine, thereby solving the reliability problem caused by the repeated start and stop of the electric supercharger and the problem of low EGR response speed. In addition, the precise control of the EGR loop temperature is achieved through the first coolant flow control valve and the second coolant flow control valve, so that the gas in the EGR loop is always at an appropriate temperature, which is beneficial to improving the reliability and economy of the system.

[0057] Figure 2 is a schematic structural diagram of another EGR system provided by the embodiment of the present invention. Refer to Figure 2, the EGR system includes an engine module 20 and an EGR system supercharging module 4. The engine module 20 includes an engine body 1, an engine ECU 13, an intake mechanism, and an exhaust mechanism. The intake mechanism includes an intake manifold 12, and the exhaust mechanism includes an exhaust manifold 2. The input end of the EGR system supercharging module 4 is connected to the exhaust mechanism (an output end of the exhaust manifold 2), and the output end of the EGR system supercharging module 4 is connected to the intake mechanism (an input end of the intake manifold 12); the EGR system supercharging module 4 includes an EGR controller 401 and an electric supercharger 407, and both the electric supercharger 407 and the engine ECU 13 are connected to the EGR controller 401. Optionally, the EGR system supercharging module 4 further includes a drive motor 406, a first switching valve 412, a second switching valve 413, a first pressure sensor 404, a second pressure sensor 405, a first temperature sensor 403, and a second temperature sensor 410; the control end of the drive motor 406, the control end of the first switching valve 412, the control end of the second switching valve 413, the first pressure sensor 404, the second pressure sensor 405, the first temperature sensor 403, and the second temperature sensor 410 are all connected to the EGR controller 401. The drive motor 406 is used to drive the electric supercharger 407 to operate. The input end of the electric supercharger 407 is connected to the exhaust manifold 2 of the exhaust mechanism. The input ends of the first switching valve 412 and the second switching valve 413 are both connected to the output end of the electric supercharger 407. The output end of the first switching valve 412 is connected to the intake mechanism, and the output end of the second switching valve 413 is connected to the input end of the electric supercharger 407. The first pressure sensor 404 and the first temperature sensor 403 are arranged at the input end of the electric supercharger 407, the second pressure sensor 405 is arranged at the output end of the electric supercharger 407, and the second temperature sensor 410 is arranged at the output end of the first switching valve 412.

[0058] Among them, Figure 2 The difference between the shown embodiment and Figure 1 the shown embodiment is that the electronic control three-way valve 408 is replaced by a first switching valve 412 and a second switching valve 413, and the other structures are the same. The same parts as the foregoing embodiments will not be described in detail here. When EGR is required, the EGR controller 401 controls the first switching valve 412 to open and the second switching valve 413 to close. The gas output by the electric supercharger 407 is transmitted to the intake mechanism through the first switching valve 412. When EGR is not required, the EGR controller 401 controls the first switching valve 412 to close and the second switching valve 413 to open. The gas output by the electric supercharger 407 returns to the input end of the electric supercharger 407 through the second switching valve 413.

[0059] Continue to refer to Figure 2, Optionally, the EGR system further includes a first EGR cooler 3. The EGR system supercharging module 4 further includes a second EGR cooler 409, a first coolant flow control valve 402, and a second coolant flow control valve 411. The control ends of the first coolant flow control valve 402 and the second coolant flow control valve 411 are both connected to the EGR controller 401. The input end of the electric supercharger 407 is connected to the exhaust manifold 2 of the exhaust mechanism through the first EGR cooler 3. The output end of the first switching valve 412 is connected to the intake mechanism through the second EGR cooler 409. The second temperature sensor 410 is disposed at the output end of the second EGR cooler 409. The input end of the first coolant flow control valve 402 is connected to the engine cooling circuit, and the coolant returns to the engine cooling circuit after passing through the first EGR cooler 3; the input end of the second coolant flow control valve 411 is connected to the engine cooling circuit, and the coolant returns to the engine cooling circuit after passing through the second EGR cooler 409.

[0060] Continue to refer to Figure 1 or Figure 2 , Optionally, the intake mechanism includes an air filter 7, an intercooler 9, a throttle valve 10, a mixer 11, and an intake manifold 12. The output end of the air filter 7 is connected to the input end of the intercooler 9. The output end of the intercooler 9 is connected to the first input end of the mixer 11. The output end of the second EGR cooler 409 is connected to the second input end of the mixer 11. The output end of the mixer 11 is connected to the intake manifold 12. The throttle valve 10 is disposed between the intercooler 9 and the mixer 11; the exhaust mechanism includes an exhaust manifold 2 and a post-processor 6. The first output end of the exhaust manifold 2 is connected to the input end of the electric supercharger 407. The second output end of the exhaust manifold 2 is connected to the input end of the post-processor 6.

[0061] Optionally, the engine module further includes an exhaust gas turbocharging mechanism. The exhaust gas turbocharging mechanism includes a compressor 8 and a turbine 5. The compressor 8 is disposed between the air filter 7 and the intercooler 9. The turbine 5 is disposed between the exhaust manifold 2 and the post-processor 6. The turbine 5 drives the compressor 8 to rotate through a rotating shaft, and the compressor 8 pressurizes the air filtered by the air filter 7.

[0062] Among them, the air filter 7 is used to filter the outside air sucked by the engine to prevent impurities in the air from damaging the engine cylinders. The intercooler 9 is used to cool the supercharged gas. The throttle valve 10 is used to regulate the intake air flow. The mixer 11 mixes the air sucked by the engine from the outside and the gas in the EGR and transmits it to the intake manifold 12. The exhaust manifold 2 is provided with two channels. One channel is connected to the electric supercharger 407 through the first EGR cooler 3 to supply exhaust gas to the EGR circuit. The other channel is connected to the turbine 5. The exhaust gas drives the turbine 5 to rotate. The exhaust gas passes through the exhaust port of the turbine 5 and is connected to the aftertreatment device 6. The aftertreatment device 6 can include structures such as an oxidation catalyst, a particulate trap, and a selective catalytic reduction device, and can be designed according to actual situations during specific implementation.

[0063] Based on the EGR system provided in the above embodiments, the embodiments of the present invention further provide a control method for the EGR system. Figure 3 It is a schematic flowchart of a control method for an EGR system provided by an embodiment of the present invention, which is applicable to the EGR system provided in the above embodiments. Refer to Figure 3 and the control method includes:

[0064] S110. Obtain the parameters in the EGR system supercharging module and the engine operation parameters provided by the engine ECU.

[0065] Among them, the parameters in the EGR system supercharging module are the parameters inside the module when the EGR system supercharging module is operating, and can include the pressure and temperature at the input end of the electric supercharger, the pressure and temperature at the output end of the electric supercharger, etc. The engine operation parameters can include the throttle pedal position, the engine speed, the intake air flow, the intake air pressure, etc.

[0066] S120. Determine the operating state of the engine according to the engine operation parameters. When the engine is in a non-shutdown state, adjust the working state of the electric supercharger according to the parameters in the EGR system supercharging module and the engine operation parameters provided by the engine ECU to control the EGR flow rate.

[0067] Among them, when the engine is in a non-shutdown state, the engine is running normally. Judge the EGR demand of the engine according to the parameters in the EGR system supercharging module and the engine operation parameters provided by the engine ECU. When the required EGR rate is relatively high, control the compression ratio of the electric supercharger to be relatively large. When the required EGR rate is relatively low, control the compression ratio of the electric supercharger to be relatively small. When EGR is not required, control the electric supercharger to self-circulate, and the output gas returns to the input end.

[0068] The control method of the EGR system provided by the embodiment of the present invention can achieve independent control of the EGR flow rate by using an electric supercharger, decouple the EGR flow rate from the intake control, and is beneficial to achieving high EGR rate control under all Map operating conditions of the engine. Compared with traditional natural gas engines, in order to take into account all operating conditions of the engine and avoid the problems of insufficient EGR rate and high knock risk in common operating conditions, methods such as reducing the EGR rate, using low-performance superchargers, and throttle throttling are adopted. By adopting this solution, an efficient supercharger can be matched to increase the intake pressure, which is beneficial to improving the economy, power performance, and reliability of the engine.

[0069] Optionally, referring to Figure 1 or Figure 2 , the EGR system supercharging module 4 includes a drive motor 406, a first pressure sensor 404, a second pressure sensor 405, a first temperature sensor 403, and a second temperature sensor 410, and obtains the parameters in the EGR system supercharging module and the engine operating parameters provided by the engine ECU, including:

[0070] Obtain the signals collected by the first pressure sensor, the second pressure sensor, the first temperature sensor, the second temperature sensor, the current speed of the drive motor, and the throttle pedal position, engine speed, intake air flow, intake manifold pressure sensor signal P1, and target EGR flow rate Q issued by the engine ECU 目标 .

[0071] Among them, the first pressure sensor 404 is used to measure the pressure at the input end of the electric supercharger 407, the second pressure sensor 405 is used to measure the pressure at the output end of the electric supercharger 407, the first temperature sensor 403 is used to measure the temperature at the input end of the electric supercharger 407 (the exhaust gas temperature before EGR), the second temperature sensor 410 is used to measure the temperature at the output end of the electric supercharger 407 (the gas temperature when EGR enters the intake mechanism), and the target EGR flow rate Q 目标 can be pre-calibrated according to the specific engine model.

[0072] Figure 4 is a schematic flow chart of another EGR control method provided by the embodiment of the present invention. Referring to Figure 4 , this control method includes:

[0073] S210. Obtain the parameters in the EGR system supercharging module and the engine operating parameters provided by the engine ECU.

[0074] Among them, the parameters in the EGR system supercharging module include the signals collected by the first pressure sensor, the second pressure sensor, the first temperature sensor, the second temperature sensor, the current speed of the drive motor, and the throttle pedal position, engine speed, intake air flow, intake manifold pressure sensor signal P1, and target EGR flow rate Q provided by the engine ECU目标 。

[0075] S220. Calculate the target boost pressure of the electric supercharger according to the intake manifold pressure sensor signal and in combination with the calibrated Map of the flow rate and pressure loss of the pipeline between the electric supercharger and the intake manifold.

[0076] Among them, the calibrated Map of the flow rate and pressure loss of the pipeline between the electric supercharger and the intake manifold can be pre-calibrated using an engine test bench, and the target boost pressure P2 can be obtained by looking up the Map according to the aforementioned parameters.

[0077] S230. Calculate the target speed of the drive motor according to the target EGR flow rate, the pressure of the first pressure sensor, the target boost pressure, the temperature of the first temperature sensor, and the gas flow equation of the gas flowing through the electric supercharger, and adjust the current speed of the drive motor to the target speed.

[0078] According to the target EGR flow rate Q 目标 、the pressure P3 of the first pressure sensor, the target boost pressure P2, and the temperature T of the first temperature sensor in , in combination with the gas flow equation Q = f(p3, p2, n, T in )(the gas flow rate is a function related to pressure, speed, and temperature, and the specific expression can be calibrated according to the actual situation), the target speed n of the drive motor can be calculated, and the current speed of the drive motor can be adjusted to the target speed.

[0079] S240. Calculate the actual EGR flow rate according to the pressure of the first pressure sensor, the pressure of the second pressure sensor, the temperature of the first temperature sensor, and the gas flow equation of the gas flowing through the electric supercharger.

[0080] It can be understood that since there may be deviations during actual operation, it is necessary to further calculate the actual EGR flow rate Q according to the pressure of the first pressure sensor, the pressure of the second pressure sensor, the temperature of the first temperature sensor, and the gas flow equation of the gas flowing through the electric supercharger. 实际 。

[0081] S250. When the engine is not in the shutdown state, obtain the magnitude of the target EGR flow rate.

[0082] S261. When the target EGR flow rate is 0, control the gas at the output end of the electric supercharger to return to the input end of the electric supercharger, and at the same time control the speed of the drive motor to the idling state and maintain the self-circulation mode of the electric supercharger.

[0083] Among them, when the target EGR flow rate Q 目标When it is 0, it indicates that the operating condition at this time does not require EGR. At this time, the gas at the output end of the electric supercharger is controlled to return to the input end of the electric supercharger. By maintaining the self-circulation mode of the electric supercharger, the repeated start and stop of the electric supercharger can be avoided, and the system reliability can be improved.

[0084] S262. When the target EGR flow rate is not 0, control the gas at the output end of the electric supercharger to be transmitted to the intake mechanism, compare the actual EGR flow rate with the target EGR flow rate. When the actual EGR flow rate is equal to the target EGR flow rate, maintain the rotational speed of the drive motor. When the actual EGR flow rate is not equal to the target EGR flow rate, adjust the rotational speed of the drive motor until the actual EGR flow rate is equal to the target EGR flow rate.

[0085] Among them, when the target EGR flow rate Q 目标 ≠0, it indicates that the operating condition at this time requires EGR. Control the gas at the output end of the electric supercharger to be transmitted to the intake mechanism, and compare the actual EGR flow rate Q 实际 with the target EGR flow rate Q 实际 . When Q 实际 =Q 目标 , maintain the rotational speed of the drive motor. When Q 实际 ≠Q 目标 , adjust the rotational speed of the drive motor until Q 实际 =Q 目标 .

[0086] In an embodiment, referring to Figure 1 , optionally, the EGR system supercharging module 4 includes an electronically controlled three-way valve 408. When the target EGR flow rate is 0, the electronically controlled three-way valve 408 switches to the second channel, so that the gas at the output end of the electric supercharger 407 returns to the input end of the electric supercharger 407; when the target EGR flow rate is not 0, the electronically controlled three-way valve 408 switches to the first channel, so that the gas at the output end of the electric supercharger 407 is transmitted to the intake mechanism.

[0087] In another embodiment, referring to Figure 2 , optionally, the EGR system supercharging module 4 includes a first switching valve 412 and a second switching valve 413. When the target EGR flow rate is 0, the first switching valve 412 is closed and the second switching valve 413 is opened, so that the gas at the output end of the electric supercharger 407 returns to the input end of the electric supercharger 407; when the target EGR flow rate is not 0, the first switching valve 412 is opened and the second switching valve 43 is closed, so that the gas at the output end of the electric supercharger 407 is transmitted to the intake mechanism.

[0088] This embodiment uses an electronically controlled three-way valve or two switching valves to switch the air flow channel, and a high-speed DC motor with motor and generator functions as a driving motor, which can ensure that the motor never stops during engine operation, thereby solving the reliability problem caused by repeated starting and stopping of the electric compressor, and the problem of low EGR responsiveness speed.

[0089] refer to Figure 1 or Figure 2 Optionally, the EGR system further includes a first EGR cooler 3, and the EGR system supercharging module 4 further includes a second EGR cooler 409, a first coolant flow control valve 402, and a second coolant flow control valve 411. The control method of the EGR system provided by the embodiment of the present invention also includes:

[0090] When the engine is running or the ambient temperature is higher than the first preset temperature, the EGR controller controls the opening of the first coolant flow control valve so that the temperature of the first temperature sensor is greater than the second preset temperature. The EGR controller controls the second coolant flow control valve to be fully opened so that the second EGR cooler operates at maximum cooling capacity.

[0091] When the temperature of the first temperature sensor is greater than or equal to the second preset temperature, the EGR controller controls to maintain the current opening of the first coolant flow control valve; when the temperature of the first temperature sensor is less than the second preset temperature, the EGR controller controls to adjust the opening of the first coolant flow control valve until the temperature of the first temperature sensor is greater than or equal to the second preset temperature, and at the same time controls the second coolant flow control valve to be fully opened, and the second EGR cooler works at its maximum cooling capacity to reduce the temperature of the cooled EGR gas as much as possible, thereby fully improving the thermal efficiency of the engine.

[0092] When the engine is in a shutdown state and the ambient temperature is lower than a first preset temperature, the EGR controller controls the opening of the first coolant flow control valve and the second coolant flow control valve so that the temperature of the first temperature sensor is greater than or equal to the second preset temperature, the temperature of the second temperature sensor is greater than or equal to the third preset temperature, and the engine is shut down after maintaining operation for a preset time to prevent water vapor in the EGR gas from condensing into water and freezing at low temperatures, thereby causing system failure. The preset time can be calibrated according to actual conditions, and the embodiments of the present invention are not limited to this.

[0093] When the temperature sensed by the first temperature sensor is greater than or equal to the second preset temperature and the temperature sensed by the second temperature sensor is greater than or equal to the third preset temperature, the EGR controller controls to maintain the current opening degrees of the first coolant flow control valve and the second coolant flow control valve; when the temperature of the first temperature sensor is less than the second preset temperature and the temperature of the second temperature sensor is less than the third preset temperature, the EGR controller controls to adjust the opening degrees of the first coolant flow control valve and the second coolant flow control valve until the temperature of the first temperature sensor is greater than or equal to the second preset temperature and the temperature of the second temperature sensor is greater than or equal to the third preset temperature.

[0094] Wherein, the second preset temperature is greater than the third preset temperature, and the third preset temperature is greater than the first preset temperature. Their specific values can be calibrated according to actual situations, and the embodiments of the present invention do not limit this.

[0095] The technical solution of the embodiments of the present invention realizes precise control of the temperature of the EGR circuit through the first coolant flow control valve and the second coolant flow control valve, so that the gas in the EGR circuit is always at an appropriate temperature, which is beneficial to improving the reliability and economy of the system.

[0096] The embodiments of the present invention also provide a vehicle, including the EGR system provided in the above embodiments, where the vehicle includes but is not limited to passenger vehicles, commercial vehicles, industrial vehicles, agricultural machinery, etc.

[0097] Since the vehicle provided in the embodiments of the present invention includes the EGR system provided in the above embodiments and has the same or corresponding technical effects as the EGR system, details are not described here again.

[0098] It should be understood that the various forms of the processes shown above can be used, steps can be reordered, added or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this is not limited herein.

[0099] The above specific embodiments do not constitute a limitation to the protection scope. Those skilled in the art should understand that various modifications, combinations, sub - combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An EGR system, characterized in that, It includes an engine module and an EGR system supercharging module. The engine module includes an engine body, an engine ECU, an intake mechanism, and an exhaust mechanism. The input end of the EGR system supercharging module is connected to the exhaust mechanism, and the output end of the EGR system supercharging module is connected to the intake mechanism; The EGR system supercharging module includes an EGR controller and an electric compressor. Both the electric compressor and the engine ECU are connected to the EGR controller. The EGR controller is used to adjust the working state of the electric compressor according to the parameters in the EGR system supercharging module and the engine operation parameters provided by the engine ECU to control the EGR flow rate.

2. The EGR system according to claim 1, wherein The EGR system supercharging module further includes a drive motor, an electronically controlled three-way valve, a first pressure sensor, a second pressure sensor, a first temperature sensor, and a second temperature sensor; The control end of the drive motor, the control end of the electronically controlled three-way valve, the first pressure sensor, the second pressure sensor, the first temperature sensor, and the second temperature sensor are all connected to the EGR controller. The drive motor is used to drive the electric compressor to operate. The input end of the electric compressor is connected to the exhaust manifold of the exhaust mechanism. The output end of the electric compressor is connected to the input end of the electronically controlled three-way valve. The first output end of the electronically controlled three-way valve is connected to the intake mechanism. The second output end of the electronically controlled three-way valve is connected to the input end of the electric compressor. The first pressure sensor and the first temperature sensor are arranged at the input end of the electric compressor. The second pressure sensor is arranged at the output end of the electric compressor. The second temperature sensor is arranged at the first output end of the electronically controlled three-way valve.

3. The EGR system according to claim 2, wherein It further includes a first EGR cooler. The EGR system supercharging module further includes a second EGR cooler, a first coolant flow control valve, and a second coolant flow control valve. The control ends of the first coolant flow control valve and the second coolant flow control valve are both connected to the EGR controller. The input end of the electric compressor is connected to the exhaust manifold of the exhaust mechanism through the first EGR cooler. The first output end of the electronically controlled three-way valve is connected to the intake mechanism through the second EGR cooler. The second temperature sensor is arranged at the output end of the second EGR cooler. The input end of the first coolant flow control valve is connected to the engine cooling circuit, and the coolant returns to the engine cooling circuit after passing through the first EGR cooler; the input end of the second coolant flow control valve is connected to the engine cooling circuit, and the coolant returns to the engine cooling circuit after passing through the second EGR cooler.

4. The EGR system according to claim 1, characterized in that, The EGR system supercharging module further includes a drive motor, a first switching valve, a second switching valve, a first pressure sensor, a second pressure sensor, a first temperature sensor, and a second temperature sensor; The control terminal of the drive motor, the control terminal of the first switching valve, the control terminal of the second switching valve, the first pressure sensor, the second pressure sensor, the first temperature sensor, and the second temperature sensor are all connected to the EGR controller. The drive motor is used to drive the operation of the electric supercharger. The input end of the electric supercharger is connected to the exhaust manifold of the exhaust mechanism. The input ends of the first switching valve and the second switching valve are both connected to the output end of the electric supercharger. The output end of the first switching valve is connected to the intake mechanism. The output end of the second switching valve is connected to the input end of the electric supercharger. The first pressure sensor and the first temperature sensor are arranged at the input end of the electric supercharger. The second pressure sensor is arranged at the output end of the electric supercharger. The second temperature sensor is arranged at the output end of the first switching valve.

5. The EGR system according to claim 4, wherein It further includes a first EGR cooler. The EGR system boosting module further includes a second EGR cooler, a first coolant flow control valve, and a second coolant flow control valve. The control terminals of the first coolant flow control valve and the second coolant flow control valve are both connected to the EGR controller. The input end of the electric supercharger is connected to the exhaust manifold of the exhaust mechanism through the first EGR cooler. The output end of the first switching valve is connected to the intake mechanism through the second EGR cooler. The second temperature sensor is arranged at the output end of the second EGR cooler. The input end of the first coolant flow control valve is connected to the engine cooling circuit, and the coolant returns to the engine cooling circuit after passing through the first EGR cooler; the input end of the second coolant flow control valve is connected to the engine cooling circuit, and the coolant returns to the engine cooling circuit after passing through the second EGR cooler.

6. The EGR system according to claim 3 or 5, characterized in that, The intake mechanism includes an air filter, an intercooler, a throttle valve, a mixer, and an intake manifold. The output end of the air filter is connected to the input end of the intercooler. The output end of the intercooler is connected to the first input end of the mixer. The output end of the second EGR cooler is connected to the second input end of the mixer. The output end of the mixer is connected to the intake manifold. The throttle valve is arranged between the intercooler and the mixer; The exhaust mechanism includes an exhaust manifold and a post-processor. The first output end of the exhaust manifold is connected to the input end of the electric supercharger. The second output end of the exhaust manifold is connected to the input end of the post-processor.

7. The EGR system according to claim 6, characterized in that, The engine module further includes an exhaust gas turbocharging mechanism. The exhaust gas turbocharging mechanism includes a compressor and a turbine. The compressor is arranged between the air filter and the intercooler. The turbine is arranged between the exhaust manifold and the post-processor. The turbine drives the compressor to rotate through a rotating shaft. The compressor pressurizes the air filtered by the air filter.

8. A control method for an EGR system, characterized in that, Applicable to the EGR system according to any one of claims 1 to 7, the control method includes: Obtain the parameters in the EGR system supercharging module and the engine operating parameters provided by the engine ECU; Determine the operating state of the engine according to the engine operating parameters. When the engine is in a non-shutdown state, adjust the operating state of the electric supercharger according to the parameters in the EGR system supercharging module and the engine operating parameters provided by the engine ECU to control the EGR flow rate.

9. The control method of the EGR system according to claim 8, characterized in that, The EGR system supercharging module includes a drive motor, a first pressure sensor, a second pressure sensor, a first temperature sensor, and a second temperature sensor. Obtaining the parameters in the EGR system supercharging module and the engine operating parameters provided by the engine ECU includes: Obtain the signals collected by the first pressure sensor, the second pressure sensor, the first temperature sensor, the second temperature sensor, the current speed of the drive motor, and the throttle pedal position, engine speed, intake air flow rate, intake manifold pressure sensor signal, and target EGR flow rate issued by the engine ECU.

10. The control method of the EGR system according to claim 9, characterized in that, After obtaining the parameters in the EGR system supercharging module and the engine operating parameters provided by the engine ECU, it further includes: According to the intake manifold pressure sensor signal, calculate the target boost pressure of the electric supercharger by combining the calibration Map of the flow rate and pressure loss of the pipeline between the electric supercharger and the intake manifold; According to the target EGR flow rate, the pressure of the first pressure sensor, the target boost pressure, the temperature of the first temperature sensor, and the gas flow equation of the gas flowing through the electric supercharger, calculate the target speed of the drive motor and adjust the current speed of the drive motor to the target speed; According to the pressure of the first pressure sensor, the pressure of the second pressure sensor, the temperature of the first temperature sensor, and the gas flow equation of the gas flowing through the electric supercharger, calculate the actual EGR flow rate.

11. The control method of the EGR system according to claim 10, characterized in that, When the engine is in a non-shutdown state, adjust the operating state of the electric supercharger according to the parameters in the EGR system supercharging module and the engine operating parameters provided by the engine ECU to control the EGR flow rate, including: When the engine is in a non-shutdown state, obtain the magnitude of the target EGR flow rate; When the target EGR flow rate is 0, control the gas at the output end of the electric supercharger to return to the input end of the electric supercharger, and at the same time control the speed of the drive motor to the idling state and maintain the self-circulation mode of the electric supercharger; When the target EGR flow rate is not 0, control the gas at the output end of the electric supercharger to be transmitted to the intake mechanism, compare the actual EGR flow rate with the target EGR flow rate. When the actual EGR flow rate is equal to the target EGR flow rate, keep the speed of the drive motor. When the actual EGR flow rate is not equal to the target EGR flow rate, adjust the speed of the drive motor until the actual EGR flow rate is equal to the target EGR flow rate.

12. The control method of the EGR system according to claim 11, characterized in that, The EGR system supercharging module includes an electronically controlled three-way valve. When the target EGR flow rate is 0, the electronically controlled three-way valve switches to the second channel, so that the gas at the output end of the electric supercharger returns to the input end of the electric supercharger; when the target EGR flow rate is not 0, the electronically controlled three-way valve switches to the first channel, so that the gas at the output end of the electric supercharger is transmitted to the intake mechanism.

13. The control method of the EGR system according to claim 11, characterized in that, The EGR system supercharging module includes a first switching valve and a second switching valve. When the target EGR flow rate is 0, the first switching valve closes and the second switching valve opens, so that the gas at the output end of the electric supercharger returns to the input end of the electric supercharger; when the target EGR flow rate is not 0, the first switching valve opens and the second switching valve closes, so that the gas at the output end of the electric supercharger is transmitted to the intake mechanism.

14. The control method of the EGR system according to claim 9, characterized in that, The EGR system further includes a first EGR cooler. The EGR system supercharging module further includes a second EGR cooler, a first coolant flow control valve, and a second coolant flow control valve; the control method further includes: When the engine is running or the ambient temperature is higher than a first preset temperature, the EGR controller controls the opening degree of the first coolant flow control valve so that the temperature of the first temperature sensor is higher than a second preset temperature; When the temperature of the first temperature sensor is greater than or equal to the second preset temperature, the EGR controller controls to maintain the current opening degree of the first coolant flow control valve; when the temperature of the first temperature sensor is less than the second preset temperature, the EGR controller controls to adjust the opening degree of the first coolant flow control valve until the temperature of the first temperature sensor is greater than or equal to the second preset temperature, and at the same time controls the second coolant flow control valve to be fully open; When the engine is in a shutdown state and the ambient temperature is lower than the first preset temperature, the EGR controller controls the opening degrees of the first coolant flow control valve and the second coolant flow control valve so that the temperature of the first temperature sensor is greater than or equal to the second preset temperature, and the temperature of the second temperature sensor is greater than or equal to a third preset temperature, and stops after running for a preset time; When the temperature of the first temperature sensor is greater than or equal to the second preset temperature and the temperature of the second temperature sensor is greater than or equal to the third preset temperature, the EGR controller controls to maintain the current opening degrees of the first coolant flow control valve and the second coolant flow control valve; when the temperature of the first temperature sensor is less than the second preset temperature and the temperature of the second temperature sensor is less than the third preset temperature, the EGR controller controls to adjust the opening degrees of the first coolant flow control valve and the second coolant flow control valve until the temperature of the first temperature sensor is greater than or equal to the second preset temperature and the temperature of the second temperature sensor is greater than or equal to the third preset temperature; Wherein, the second preset temperature is greater than the third preset temperature, and the third preset temperature is greater than the first preset temperature.

15. A vehicle, characterized in that, An EGR system according to any one of claims 1 to 7.

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