Control method for electric auxiliary two-stage pressurization system of opposed-piston two-stroke diesel engine

Abstract

The invention provides a control method for an electrically-assisted two-stage supercharging system of an opposed-piston two-stroke diesel engine. The control method comprises the steps that an engine signal is collected through a sensor network and subjected to signal preprocessing; wherein the engine signals comprise a rotating speed signal, a load signal, a scavenging pressure signal, a turbine front exhaust pressure signal and a scavenging temperature signal; performing mode division on different working conditions of the diesel engine according to the rotating speed and the load parameters of the engine and on the basis of the required scavenging pressure and the turbine natural capacity determined by the simulation test; and according to the working modes divided under different working conditions, control strategies corresponding to the working modes are executed so as to dynamically coordinate the working states of the electric supercharger and the auxiliary motor. According to the method, the starting problem of the OP2S diesel engine and the problem of insufficient scavenging caused by low air inlet pressure under the low-speed working condition are solved, efficient pressurization and quick response within the full-working-condition range are achieved, and optimal system-level energy efficiency is achieved through intelligent energy management.

Description

Technical Field

[0001] This application belongs to the field of internal combustion engine turbocharging technology, and particularly relates to a control method for an electrically assisted two-stage turbocharging system for a opposed piston two-stroke diesel engine. Background Technology

[0002] Opposed-piston two-stroke diesel engines feature two pistons that move relative to each other within the same cylinder, eliminating the need for a traditional cylinder head and valve train. This results in advantages such as high power density, high mechanical efficiency, and low heat loss, making it a promising candidate for applications in vehicles, marine propulsion, and special equipment. However, the OP2S diesel engine's scavenging process relies entirely on the intake and exhaust pressure difference provided by the turbocharger system. This differs from traditional two-stroke and four-stroke engines, which rely on the crankcase for pressure differential and have separate intake and exhaust strokes. This makes the OP2S engine far more sensitive to the turbocharger system's performance than traditional engines.

[0003] Therefore, the core technological challenges facing the OP2S diesel engine include: (1) Difficult to start: The scavenging process of the OP2S diesel engine relies entirely on the intake and exhaust pressure difference provided by the turbocharger system. Without the turbocharger to provide the intake and exhaust pressure difference, the diesel engine cannot be started by directly driving the diesel engine with the electric motor. (2) Difficulty in scavenging at low speed: Under low speed and low load conditions, insufficient exhaust gas energy leads to low turbine speed and insufficient compressor outlet pressure, making it impossible to establish an effective scavenging pressure difference, resulting in incomplete scavenging, deteriorated combustion, and a sharp increase in carbon soot emissions. (3) Difficulty in improving high-speed performance: The turbine inlet pressure is high at high speeds. To ensure the power of the diesel engine at high speeds, a higher intake pressure is required to provide an intake-exhaust pressure difference to ensure sufficient scavenging. However, the high intake pressure leads to excessively high in-cylinder combustion pressure, which limits the improvement of diesel engine power.

[0004] Existing turbocharging technologies have significant shortcomings in addressing the aforementioned issues. While traditional two-stage turbocharging systems can broaden the flow range, they remain purely passive systems and cannot solve starting problems or scavenging issues at extremely low engine speeds. Simple electric superchargers offer rapid response but lack energy recovery mechanisms, resulting in low system efficiency. Furthermore, conventional electric-assisted turbocharging technology offers limited assistance at extremely low engine speeds because the turbine itself is almost inactive.

[0005] More importantly, most existing technologies are developed for traditional four-stroke engines or ordinary two-stroke engines, and there is a lack of customized solutions specifically for the special scavenging requirements of the OP2S diesel engine. Summary of the Invention

[0006] In view of this, this application aims to propose a control method for an electrically assisted two-stage turbocharging system for an opposed piston two-stroke diesel engine, in order to solve at least one of the above-mentioned problems.

[0007] To achieve the above objectives, the technical solution of this application is implemented as follows: In a first aspect, this application provides a control method for an electrically assisted two-stage turbocharging system for a opposed-piston two-stroke diesel engine, comprising: Engine signals are acquired through a sensor network and preprocessed; the engine signals include speed signal, load signal, scavenging pressure signal, turbine inlet exhaust pressure signal, and scavenging temperature signal. Based on engine speed and load parameters, and on the required scavenging pressure and turbine natural capacity determined by simulation tests, the diesel engine is classified into different operating modes. Based on the different operating modes under different working conditions, the corresponding control strategy under the operating mode is executed to dynamically coordinate the working state of the electric supercharger and the auxiliary motor. The control strategy includes obtaining the intake air mass flow rate based on the processed scavenging pressure, the turbine inlet exhaust pressure and the scavenging temperature, determining the optimal pressure ratio value under the current flow rate based on the intake air mass flow rate, determining the first-stage outlet boundary based on the optimal pressure ratio value and the pre-calibrated target scavenging pressure, and then adjusting the electric supercharger and the auxiliary motor.

[0008] Secondly, based on the same inventive concept, this application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method described in the first aspect.

[0009] Thirdly, based on the same inventive concept, this application also provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions for causing the computer to perform the method as described in the first aspect.

[0010] Compared with the prior art, the control method of the electrically assisted two-stage turbocharging system for opposed piston two-stroke diesel engines described in this application has the following advantages: The control method for an electrically assisted two-stage turbocharging system for an opposed-piston two-stroke diesel engine described in this application solves the starting problem of the OP2S diesel engine and the problem of insufficient scavenging caused by low intake pressure at low speeds. It achieves efficient turbocharging and rapid response across the entire operating range and achieves optimal system-level energy efficiency through intelligent energy management. Attached Figure Description

[0011] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a flowchart illustrating a control method for an electrically assisted two-stage turbocharging system for a opposed-piston two-stroke diesel engine, as described in an embodiment of this application. Figure 2 This is a schematic diagram of the structure of an electrically assisted two-stage turbocharging system for a opposed-piston two-stroke diesel engine, as described in an embodiment of this application. Figure 3 This is a schematic diagram of the connection structure of the planetary gear mechanism described in the embodiments of this application; Figure 4 This is a schematic diagram illustrating the four-mode region division based on rotational speed and load as described in an embodiment of this application; Figure 5 This is a schematic diagram of the hardware structure of the electronic device described in an embodiment of this application. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0013] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0014] The embodiments of this application are described in detail below with reference to the accompanying drawings.

[0015] Please see Figure 1 As shown, this embodiment provides a control method for an electrically assisted two-stage turbocharging system of a opposed-piston two-stroke diesel engine, specifically including the following steps: Step S10: Collect engine signals through the sensor network and perform signal preprocessing.

[0016] Specifically, in this embodiment, such as Figure 2As shown, the electric auxiliary two-stage turbocharging system for the opposed piston two-stroke diesel engine in this embodiment adopts a basic architecture of a fast-response stage electric turbocharger and an energy recovery stage electric auxiliary turbocharger connected in series. The system monitors the engine status in real time through a precision sensor network. Among them, the fast-response electric booster adopts a high-speed permanent magnet synchronous motor to directly drive a centrifugal compressor with a rated speed of 100,000 r / min and a response time of <200 ms. It is mainly responsible for solving the scavenging air demand in the low-speed range of 0-1200 r / min.

[0017] Energy recovery-stage electric-assisted variable speed turbocharger: A turbocharger that integrates an auxiliary motor (disc motor / generator) and uses a planetary gear transmission mechanism to support the decoupling of turbine and compressor speeds, responsible for efficient operation in the main operating range and energy recovery under high load.

[0018] Specific connection methods are as follows: Figure 3 As shown, the turbine is fixedly connected to one end of the main shaft, and the other end of the main shaft is rigidly connected to the sun gear of the planetary gear mechanism; therefore, the turbine's rotational speed is directly equal to the sun gear's rotational speed. The planet carrier of the planetary gear is rigidly connected to the other end of the main shaft and directly drives the compressor 2; therefore, the compressor 2's rotational speed is directly equal to the planet carrier's rotational speed, forming a transmission path of "turbine-main shaft-sun gear-(planetary gear system)-planet carrier-main shaft-compressor". In addition, the auxiliary motor is not directly connected to the main shaft, but rather meshes with the gear on the outer edge of the planetary gear ring through an intermediate gear, forming a transmission path of "auxiliary motor pinion-intermediate gear-planetary gear ring".

[0019] When the required compressor speed is higher than the turbine speed determined by the current exhaust gas energy, the auxiliary motor outputs drive torque, applying a torque in the same direction to the ring gear to make the planetary carrier speed higher than the sun gear speed. When the required compressor speed is lower than the turbine speed determined by the current exhaust gas energy, the auxiliary motor enters generator mode, applying a resistance torque to the ring gear to make the planetary carrier speed lower than the sun gear speed. Additionally, the clutch / brake assembly directly acts on the ring gear's clutch function, pushing the clutch discs towards the component connected to the sun gear, thereby locking the ring gear and sun gear together, making them a single rotating component. At this time, the planetary carrier and sun gear rotate at the same speed, meaning the turbine and compressor rotate at the same speed. Its braking function pushes a brake block towards the housing connected to the ring gear, thereby locking the ring gear and preventing it from rotating.

[0020] Exhaust solenoid bypass valve: Open the bypass valve when necessary to reduce the turbine inlet pressure and ensure the intake and exhaust pressure difference without exceeding the burst pressure limit.

[0021] The sensor network used to collect engine operating status parameters includes a speed sensor, a scavenging pressure sensor, a turbine front exhaust pressure sensor, and an exhaust temperature sensor.

[0022] The control system used to coordinate and control all actuators includes a central controller and a condition identification module.

[0023] The secondary booster system is connected in series with other devices, such as: an intake duct design optimized by CFD simulation, first and second stage intercoolers analyzed by the energy management system, and temperature and pressure sensors at various measuring points.

[0024] The central controller collects engine speed, load, scavenging pressure, turbine inlet exhaust pressure, turbine inlet exhaust temperature, and scavenging temperature signals in real time through a sensor network. It performs preprocessing such as digital filtering and rationality checks on the collected signals to ensure the stability and reliability of the control system.

[0025] Step S20: Based on engine speed and load parameters, and on the required scavenging pressure and turbine natural capacity determined by simulation tests, the diesel engine is divided into different operating modes.

[0026] Specifically, in this embodiment, the operating range of the diesel engine is divided into four zones (the division of the four operating modes is pre-prepared), specifically including: Step S201: Determine the required scavenging pressure. The required scavenging pressure is obtained through a simulated turbocharging test. The simulated turbocharging test chamber is equipped with a high-power compressor, an intake pressure regulator, and an exhaust pressure regulator. The simulated turbocharging test method can eliminate the influence of the turbocharging system and directly adjust the diesel engine's scavenging pressure and exhaust pressure to determine the required scavenging pressure under different operating conditions (required scavenging pressure: the minimum scavenging pressure that meets the performance requirements under this operating condition). Based on preliminary theoretical analysis and experiments, the intake and exhaust pressure difference of the target diesel engine should not be lower than 60 kPa; otherwise, it will lead to insufficient scavenging and affect combustion performance. During the test, the exhaust pressure is set according to this value.

[0027] Step S202: Determine the turbine natural capacity. Obtain the compressor characteristic map (CMAP) and turbine characteristic map (TMAP) through turbine and compressor component tests. Based on the exhaust pressure and air flow parameters, obtain the turbine natural capacity (turbine natural capacity: the scavenging pressure that can be provided solely by the turbine) by querying the CMAP and TMAP maps.

[0028] Step S203: Divide the diesel engine into different operating modes. Under different speed and load conditions, perform steps S201 and S202 respectively, and determine the optimal mode under different speed and load conditions based on the required scavenging pressure and turbine natural speed capability. The specific details are as follows: The conditions for determining whether to enter pure electric boost mode are: required scavenging pressure > turbocharger natural capacity and turbine inlet exhaust temperature ≤ temperature threshold (the temperature threshold set in this embodiment is 400℃). Under these conditions, the turbocharger cannot effectively output energy, and the turbine inlet exhaust pressure increases, affecting starting and scavenging at low speeds. Therefore, the turbocharger is bypassed to minimize exhaust back pressure and quickly establish a base pressure difference.

[0029] The conditions for determining whether to enter combined supercharging mode are: required scavenging pressure > turbocharger's natural capacity and turbocharger inlet exhaust temperature > 400℃. Under these conditions, the turbocharger can effectively output energy, but cannot meet the scavenging pressure requirement. Therefore, the electric supercharger and turbocharger work together.

[0030] The condition for determining whether to enter turbocharger main boost mode is: required scavenging pressure ≈ turbocharger's natural capacity. Under this condition, the energy provided by the turbocharger basically meets the scavenging pressure requirement.

[0031] The condition for determining whether to enter energy recovery mode is: required scavenging pressure < turbine's natural capacity. Under this condition, the turbine provides more energy than the required scavenging pressure, and energy recovery is initiated.

[0032] After system testing and analysis, a four-mode region division diagram based on speed and load was obtained, as shown in the schematic diagram below. Figure 4 As shown, 0~1200r / min is the pure electric boost mode; 1200r / min~1800r / min is the combined boost mode; 1800r / min~2600r / min is the turbo main boost mode, as well as the overload energy recovery mode; thus, the most suitable working mode is selected.

[0033] Step S30: Based on the working modes divided under different working conditions, execute the control strategy under the corresponding working mode to dynamically coordinate the working state of the electric booster and the auxiliary motor.

[0034] Specifically, in this embodiment, based on the selection result of step S20, the corresponding control logic is executed, as follows: Step S301: Determine the target scavenging pressure and the first-stage outlet boundary.

[0035] First, the target scavenging pressure under the current operating conditions is determined based on the diesel engine speed and load parameters. The target scavenging pressure is obtained through calibration tests across the entire operating range during the research and development process.

[0036] For the pure electric boost mode, the first stage outlet boundary is the target scavenging pressure.

[0037] In turbocharger main boost mode and overload energy recovery mode, the electric supercharger is not involved, and the first stage outlet boundary is atmospheric pressure.

[0038] For the combined turbocharging mode, the main principles for determining the first-stage outlet boundary to ensure the turbocharger operates in its high-efficiency region are as follows: The intake mass flow rate is calculated based on the scavenging pressure, exhaust pressure, and scavenging temperature. ; in, ; In the formula, Intake mass flow rate; and These are the flow coefficient and the equivalent flow area, respectively; both are related to the engine structure and speed, and are inherent properties of the engine. Intake density; This refers to the scavenging pressure; This refers to the exhaust pressure before the turbocharger. The scavenging gas temperature; is the gas constant.

[0039] Then, based on the intake mass flow rate, the turbocharger compressor characteristic diagram (CMAP) is consulted to determine the optimal pressure ratio value that maximizes efficiency at the current flow rate. Based on the target scavenging pressure and the turbocharger's optimal pressure ratio value, the first-stage outlet boundary is determined. This ensures that the engine's intake or scavenging pressure adapts to operational requirements under different operating conditions and provides a command basis for the electric supercharger. The formula for the first-stage outlet boundary is: ; In the formula, This refers to the turbocharger scavenging pressure, i.e., the first-stage outlet boundary. Target scavenging pressure; This is the optimal pressure ratio.

[0040] In this embodiment, the setting of the first-stage outlet boundary provides the basis for subsequent electric turbocharger and auxiliary motor commands. Through the precise control of these commands, the turbocharging system can operate efficiently under various operating conditions, thereby improving engine performance and fuel economy.

[0041] Step S302: Calculate the electric booster command in reverse to dynamically adjust the electric booster.

[0042] Specifically, in this embodiment, the electric supercharger does not participate in the operation of the turbocharger main boost mode and the energy recovery mode, and there are no control commands.

[0043] In pure electric turbocharging mode, the outlet pressure of the electric turbocharger is the target scavenging pressure of the engine, and the pressure ratio of the electric turbocharger can be calculated.

[0044] ; In the formula, The voltage ratio of the electric booster; Atmospheric pressure.

[0045] For the combined supercharging mode, the electric supercharger outlet pressure is the turbocharger scavenging pressure calculated in step S301. The voltage ratio of the electric booster can be calculated: .

[0046] Based on the current intake mass flow rate and electric booster voltage ratio Query the electric supercharger characteristic diagram eCMAP to obtain the target speed it needs to achieve, and use the controller to directly control the electric supercharger motor to achieve that speed.

[0047] In different operating modes, the electric supercharger improves engine intake efficiency by increasing intake pressure. Based on the target scavenging pressure (determined by the first-stage outlet boundary), the control system calculates the pressure ratio of the electric supercharger and adjusts its speed accordingly to ensure it reaches the required operating pressure.

[0048] Step S303: Calculate the auxiliary motor command to dynamically adjust the auxiliary motor.

[0049] Specifically, in this embodiment, firstly, based on the current intake air mass flow rate... and the target pressure ratio of the turbocharger By consulting the turbocharger compressor characteristic diagram (CMAP), the power required to drive the compressor can be obtained. .

[0050] Then, based on the current exhaust mass flow rate By checking the turbine inlet exhaust temperature and pressure, and referring to the turbocharger turbine characteristic map (TMAP), the effective power output of the turbine under the current exhaust gas energy can be obtained. Among them, the exhaust mass flow rate can be calculated based on the intake mass flow rate and the fuel injection mass flow rate.

[0051] Finally, the auxiliary motor commands are determined.

[0052] Specifically, in pure electric boost mode, the turbocharger does not participate in operation, and the auxiliary motor receives no control commands.

[0053] For the combined supercharging mode, calculate the power required by the compressor. and the effective power output of the turbine The difference between the two (i.e., the power gap, which is the power that the auxiliary motor needs to output) is compensated by the auxiliary motor.

[0054] In turbocharger main boost mode, the auxiliary motor mainly plays a fine-tuning role and is only used to reduce scavenging pressure fluctuations.

[0055] For energy recovery mode, based on the compressor's required power... and the effective power output of the turbine The system calculates power surplus and uses auxiliary motors to recover energy based on this surplus, thereby improving system energy efficiency.

[0056] In this embodiment, the auxiliary motor optimizes the power output of the turbocharger system by compensating for the power difference between the turbocharger and the compressor, or by recovering exhaust gas energy. The auxiliary motor adjusts its output according to the real-time power demand to ensure that the turbocharger system operates efficiently and smoothly.

[0057] The entire turbocharging system optimizes engine performance under different operating conditions through precise control strategies, based on required scavenging pressure, turbine natural capacity, compressor and turbine characteristic curves, and the coordinated control of the electric supercharger and auxiliary motor. This zoned control mode and multi-mode adjustment method ensures efficient engine operation under various load and speed conditions, providing better fuel efficiency and power response.

[0058] The method described in this embodiment is designed specifically for the scavenging characteristics of the OP2S diesel engine, completely solving the long-standing technical bottlenecks of starting difficulties and insufficient scavenging at low speeds. It achieves efficient boosting and rapid response across the entire operating range, and optimizes system-level energy efficiency through intelligent energy management. Utilizing a planetary gear transmission system, it realizes variable speed control of the electrically assisted turbocharger, improving turbocharging efficiency and response speed. Simultaneously, it enables the "high-load power generation - low-load power consumption" function.

[0059] It should be noted that the above description describes some embodiments of this application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0060] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, embodiments of this application also provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the methods described in any of the above embodiments.

[0061] Figure 5This embodiment illustrates a more specific hardware structure of an electronic device, which may include a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. The processor 1010, memory 1020, input / output interface 1030, and communication interface 1040 are interconnected internally via the bus 1050.

[0062] The processor 1010 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0063] The memory 1020 can be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 1020 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program code is stored in the memory 1020 and is called and executed by the processor 1010.

[0064] The input / output interface 1030 is used to connect input / output modules to realize information input and output. The input / output modules can be configured as components in the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Input devices may include keyboards, mice, touch screens, microphones, various sensors, etc., and output devices may include displays, speakers, vibrators, indicator lights, etc.

[0065] The communication interface 1040 is used to connect a communication module (not shown in the figure) to enable communication between this device and other devices. The communication module can communicate via wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0066] Bus 1050 includes a pathway for transmitting information between various components of the device, such as processor 1010, memory 1020, input / output interface 1030, and communication interface 1040.

[0067] It should be noted that although the above-described device only shows the processor 1010, memory 1020, input / output interface 1030, communication interface 1040, and bus 1050, in specific implementations, the device may also include other components necessary for normal operation. Furthermore, those skilled in the art will understand that the above-described device may only include the components necessary for implementing the embodiments of this specification, and not necessarily all the components shown in the figures.

[0068] The electronic devices described above are used to implement the corresponding methods in any of the foregoing embodiments and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0069] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, this application also provides a non-transitory computer-readable storage medium that stores computer instructions for causing the computer to perform the methods described in any of the above embodiments.

[0070] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0071] The computer instructions stored in the storage medium of the above embodiments are used to cause the computer to perform the methods described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0072] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in the details for the sake of brevity.

[0073] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications, and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may be used with the embodiments discussed.

[0074] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A control method for an electrically assisted two-stage turbocharging system for a opposed-piston two-stroke diesel engine, characterized in that, include: Engine signals are acquired through a sensor network and preprocessed; the engine signals include speed signal, load signal, scavenging pressure signal, turbine inlet exhaust pressure signal, and scavenging temperature signal. Based on engine speed and load parameters, and on the required scavenging pressure and turbine natural capacity determined by simulation tests, the diesel engine is classified into different operating modes. Based on the different operating modes under different working conditions, the corresponding control strategy under the operating mode is executed to dynamically coordinate the working state of the electric supercharger and the auxiliary motor. The control strategy includes obtaining the intake air mass flow rate based on the processed scavenging pressure, the turbine inlet exhaust pressure and the scavenging temperature, determining the optimal pressure ratio value under the current flow rate based on the intake air mass flow rate, determining the first-stage outlet boundary based on the optimal pressure ratio value and the pre-calibrated target scavenging pressure, and then adjusting the electric supercharger and the auxiliary motor.

2. The method according to claim 1, characterized in that: The required scavenging pressure is obtained through simulated pressurization tests; Compressor and turbine characteristic diagrams are obtained through turbine and compressor component tests. Based on exhaust pressure and air flow parameters, the turbine's natural capacity is obtained by querying the compressor and turbine characteristic diagrams.

3. The method according to claim 1, characterized in that: Based on the required scavenging pressure and the turbine's natural capacity, the optimal mode under different speed and load conditions is determined; wherein, the preferred mode includes: In response to the demand scavenging pressure being greater than the turbine's natural capacity and the turbine's exhaust temperature being less than or equal to a temperature threshold, it is determined that the system will enter pure electric boost mode. In response to the demand scavenging pressure being greater than the turbine's natural capacity and the turbine's exhaust temperature being greater than a temperature threshold, it is determined that the system will enter a combined turbocharging mode. In response to the demand for scavenging pressure approaching the turbine's natural capacity, it is determined that the turbine will enter the main boost mode. In response to the demand for scavenging pressure being less than the turbine's natural capacity, it is determined that the energy recovery mode will be entered.

4. The method according to claim 3, characterized in that, The control strategy includes: For the pure electric boost mode, the first stage outlet boundary is determined to be the pre-calibrated target scavenging pressure; In turbocharger main boost mode and energy recovery mode, the electric supercharger is not involved in operation, and the first stage outlet boundary is determined to be atmospheric pressure. For the combined supercharging mode, the compressor characteristic diagram is queried according to the intake mass flow rate to determine the optimal pressure ratio value under the current flow rate, and the first stage outlet boundary is determined according to the optimal pressure ratio value and the pre-calibrated target scavenging pressure.

5. The method according to claim 4, characterized in that, The formula for the intake mass flow rate is as follows: ； in, ; In the formula, Intake mass flow rate; and These are the flow coefficient and the equivalent flow area, respectively. Intake density; This refers to the scavenging pressure; This refers to the exhaust pressure before the turbocharger. The scavenging gas temperature; is the gas constant.

6. The method according to claim 4, characterized in that, Also includes: For pure electric turbocharging mode, the outlet pressure of the electric turbocharger is the engine's target scavenging pressure, and the pressure ratio of the electric turbocharger is calculated based on atmospheric pressure. For the combined supercharging mode, the electric supercharger outlet pressure is the first stage outlet boundary (turbocharger scavenging pressure), and the electric supercharger pressure ratio is calculated based on atmospheric pressure. Based on the current intake mass flow rate and the electric supercharger pressure ratio, the target speed is obtained by consulting the electric supercharger characteristic diagram, so as to control the electric supercharger motor to reach the target speed.

7. The method according to claim 4, characterized in that, Also includes: Based on the current intake mass flow rate and optimal pressure ratio, the power required to drive the compressor is obtained by consulting the compressor characteristic diagram; Based on the current exhaust mass flow rate, turbine inlet exhaust temperature, and turbine inlet exhaust pressure, the turbine characteristic diagram is consulted to obtain the effective power output of the turbine under the current exhaust gas energy, so as to determine the auxiliary motor command; wherein, the current exhaust mass flow rate is calculated based on the intake mass flow rate and fuel injection mass flow rate.

8. The method according to claim 7, characterized in that: For the combined supercharging mode, the power gap is determined based on the power required by the compressor and the effective power output by the turbine. The power gap is the power to be output by the auxiliary motor. For the energy recovery mode, the power surplus is determined based on the power required by the compressor and the effective power output of the turbine, and the auxiliary motor is used for energy recovery.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the method as described in any one of claims 1-8.

10. A non-transitory computer-readable storage medium, characterized in that, in, The non-transitory computer-readable storage medium stores computer instructions for causing a computer to perform the method described in any one of claims 1-8.

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