Engine plateau intake and exhaust simulation control method and test bench

Abstract

The application provides an engine highland intake and exhaust simulation control method and a test bench, and belongs to the technical field of engine environment simulation tests. The engine highland intake and exhaust simulation control method and the test bench comprise the following steps: S1, a corresponding highland working condition preset table item is established according to a target working condition index, wherein the working condition index at least comprises a target simulation altitude, an engine model, a calibration speed and a calibration load; S2, a theoretical initial value of an actuator is generated by theoretically estimating a target intake pressure, a target intake temperature, a target exhaust back pressure and exhaust temperature limit values corresponding to the target simulation altitude; and the control parameters corresponding to different altitudes, engine models and running working conditions are stored by establishing the highland working condition preset table, so that the historical calibration parameters can be directly called when the test is performed again, the actuator can quickly enter a target state, and the repeated adjustment process is reduced.

Description

Technical Field

[0001] This invention belongs to the field of engine environmental simulation test technology, specifically relating to an engine high-altitude intake and exhaust simulation control method and test bench. Background Technology

[0002] With the development of engine technology, engines need to meet the operating requirements under different environmental conditions. In high-altitude areas, the reduced air density and atmospheric pressure lead to a decrease in engine intake air volume and changes in combustion state. At the same time, the exhaust back pressure conditions also change, thus affecting engine power performance, fuel economy, and emissions performance.

[0003] To study the operating characteristics of engines in high-altitude environments, it is usually necessary to use a high-altitude environment simulation test system to simulate the actual high-altitude environment by adjusting parameters such as engine intake pressure, intake temperature, exhaust back pressure, and exhaust temperature.

[0004] Existing engine high-altitude simulation systems typically employ manual settings or simple closed-loop control methods, adjusting the intake pressure regulating equipment, exhaust pressure regulating equipment, and cooling system according to the atmospheric parameters corresponding to the target altitude during the test.

[0005] However, the control parameters vary greatly between different simulated altitudes, different engine models, and different load conditions. Each test requires readjustment of the actuator, resulting in long test preparation time and poor consistency of repeated tests. At the same time, during engine start-up, the changes in the engine's intake and exhaust flow cause significant disturbances in parameters such as intake pressure and exhaust back pressure. If a dynamic closed-loop control method is used directly, it is easy to cause the actuator to adjust lag, resulting in the engine being unable to quickly enter the target high-altitude operating conditions. Summary of the Invention

[0006] The purpose of this invention is to provide a method and test bench for simulating engine intake and exhaust at high altitudes, which aims to solve the problems of repeated manual adjustments and long time to enter the target operating condition in the existing technology during engine high-altitude simulation.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for simulating engine intake and exhaust control at high altitudes, comprising the following steps: S1. Establish corresponding plateau working condition preset table entries based on the target working condition index. The working condition index includes at least the target simulated altitude, engine model, calibration speed and calibration load. S2. Based on the target intake pressure, target intake temperature, target exhaust back pressure and exhaust temperature limit corresponding to the target simulated altitude, perform theoretical estimation to generate the theoretical initial value of the actuator; S3. Perform static pre-calibration with the engine off, so that the intake-side actuator enters the preset state according to the theoretical initial value, and correct the intake pressure regulating fan, intake-side electric control valve, intake cooling water regulating valve and electric heating branch according to the intake pressure feedback of the first pressure sensor, the intake temperature feedback of the second temperature sensor and the exhaust-side static pressure feedback of the second pressure sensor. When the static working condition meets the first criterion, write the corrected calibration stable value into the plateau working condition preset table. S4. Start the engine and enter the predetermined low-load calibration condition. Based on the exhaust back pressure feedback from the second pressure sensor and the exhaust temperature feedback from the third temperature sensor, dynamically correct the exhaust pressure regulating fan, the exhaust side electric control valve and the exhaust cooling water regulating valve. When the dynamic condition meets the first criterion, the formed exhaust side dynamic correction benchmark value is added to the plateau condition preset table. S5. During formal operation, the main controller calls the calibration stability value in the corresponding plateau working condition preset table according to the target working condition index, so that each actuator enters the preset state. S6. When the static parameters meet the second criterion, the engine is allowed to enter a low-load operating state, and the corresponding exhaust-side dynamic correction reference value is called. S7. The main controller performs feedback fine-tuning based on the feedback from the second pressure sensor and the third temperature sensor. When the dynamic working condition meets the second criterion and is maintained for a set time, it enters the formal test working condition and continues to perform maintenance feedback fine-tuning during the formal test. For the same controlled parameter, the permissible error corresponding to the second criterion is less than the permissible error corresponding to the first criterion.

[0008] As a simulated control method for engine intake and exhaust at high altitudes according to the present invention, preferably, the high-altitude operating condition preset table includes at least: operating condition index, target parameters, theoretical initial values, calibrated stable values, exhaust-side dynamic correction reference values, and criterion parameters; The target parameters include target intake pressure, target intake temperature, target exhaust back pressure, and exhaust temperature limit. The theoretical initial values ​​include the intake pressure regulating fan speed, the exhaust pressure regulating fan speed, the opening degree of the intake side electric control valve, the opening degree of the exhaust side electric control valve, the opening degree of the intake cooling water regulating valve, the opening degree of the exhaust cooling water regulating valve, and the power of the electric heating branch.

[0009] As a simulated control method for engine intake and exhaust at high altitudes according to the present invention, preferably, during the static pre-calibration process, the main controller determines the correction amount of the actuator according to the deviation direction and deviation amplitude between the target value and the feedback value, and uses an incremental method to correct the intake pressure regulating fan, intake side electric control valve, intake cooling water regulating valve and electric heating branch, and each correction is limited by the maximum adjustment step size.

[0010] As a simulated control method for engine intake and exhaust at high altitudes according to the present invention, preferably, during the static pre-calibration process, only the calibrated stable values ​​of the intake pressure corresponding to the first pressure sensor, the intake temperature corresponding to the second temperature sensor, and the static pressure on the exhaust side corresponding to the second pressure sensor are established, and the third temperature sensor is only used for condition monitoring or safety monitoring.

[0011] As a simulated control method for engine intake and exhaust at high altitudes according to the present invention, preferably, during the low-load dynamic calibration process, the main controller performs joint correction on the exhaust pressure regulating fan, the exhaust-side electric control valve and the exhaust cooling water regulating valve based on the feedback from the second pressure sensor and the third temperature sensor, so as to form a dynamic correction reference value on the exhaust side.

[0012] As a simulated control method for engine intake and exhaust at high altitudes according to the present invention, preferably, in the formal operation stage, the main controller first calls the calibration stable value in the high altitude operating condition preset table to establish the target static operating condition, and then calls the exhaust side dynamic correction reference value to establish the target dynamic operating condition. The two stages are respectively based on the corresponding second criterion for feedback control.

[0013] As a simulated control method for engine intake and exhaust at high altitudes according to the present invention, preferably, the first criterion includes a first allowable error and a first stable holding time; The second criterion includes a second allowable error and a second stable holding time; Among them, the second permissible error corresponding to the same controlled parameter is less than the first permissible error.

[0014] As a high-altitude intake and exhaust simulation test bench for engines according to the present invention, preferably, it includes an engine, and further includes an intake simulation pipeline disposed on the intake side of the engine and an exhaust simulation pipeline disposed on the exhaust side of the engine. The intake simulation pipeline includes an intake blower, an intake cooling pipe, a heater, and an intake main pipe connected in sequence along the gas flow direction. The intake cooling pipe is connected to an intake cooling water regulating valve for adjusting the flow rate of the cooling medium. The main intake pipe is connected to an intake pressure regulating bypass. The intake pressure regulating bypass includes an intake-side electric control valve, an intake pressure stabilizing tank, an intake pressure regulating fan, an intake storage tank, and an intake-side exhaust switch valve arranged sequentially along the gas flow direction. The intake pressure stabilizing tank is equipped with a second temperature sensor for detecting the intake temperature and a first pressure sensor for detecting the intake pressure. The exhaust simulation pipeline includes an exhaust main pipe connected to the engine exhaust port. The exhaust main pipe is sequentially connected along the gas flow direction to an exhaust pressure stabilizing tank, an exhaust-side electric control valve, an exhaust pressure regulating fan, an exhaust cooling pipe, an exhaust gas storage tank, and an exhaust-side external discharge switch valve. The exhaust cooling pipe is connected to an exhaust cooling water regulating valve for adjusting the flow rate of the cooling medium. The exhaust pressure stabilizing tank is equipped with a third temperature sensor for detecting the exhaust temperature and a second pressure sensor for detecting the exhaust pressure.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This method and test bench for simulating intake and exhaust control of engines at high altitudes establishes a high-altitude operating condition preset table, which stores the control parameters corresponding to different altitudes, engine models and operating conditions. When testing again, the historical calibration parameters can be directly called up, enabling the actuator to quickly enter the target state and reducing the repeated adjustment process.

[0016] 2. The proposed engine high-altitude intake and exhaust simulation control method and test bench divides the control process into a static pre-calibration stage before engine start-up and a dynamic correction stage after start-up, thereby avoiding disturbance to the intake environment during engine start-up and improving the system's ability to enter a stable state.

[0017] 3. The engine high-altitude intake and exhaust simulation control method and test bench adopt the first criterion for pre-calibration, and quickly establish basic parameters with a relatively wide allowable error; adopt the second criterion for formal operation control, and ensure high precision in the test stage with a smaller allowable error.

[0018] 4. This method and test bench for simulating engine intake and exhaust at high altitudes establishes parameter correlation through operating condition index, enabling independent control parameters to correspond to different simulated altitudes, engine models, speeds, and load conditions, thereby improving the system's applicability.

[0019] 5. This invention relates to a high-altitude intake and exhaust simulation control method and test bench for engines. The controller can automatically complete theoretical parameter generation, static correction, dynamic correction, and formal operation feedback control, reducing manual intervention and improving test repeatability. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the hardware structure of the high-altitude intake and exhaust simulation test bench for the engine of the present invention; Figure 2 This is a block diagram of the control system of the present invention; Figure 3This is a schematic diagram illustrating the fields and usage relationships of the plateau working condition preset table of the present invention; Figure 4 This is a flowchart of the table establishment and calibration stage in the control method of the present invention; Figure 5 This is a flowchart of the formal operation phase of the control method of the present invention.

[0021] In the diagram: 1-Outdoor air inlet; 2-Intake air blower (F1); 3-Intake cooling pipe; 4-Intake cooling water regulating valve (V1); 5-Intake cooling water inlet; 6-Intake cooling water outlet; 7-First temperature sensor (T1); 8-1-Heater volume; 8-2-Electric heating branch; 9-Intake main pipe; 10-Engine; 11-Intake side electric control valve (V2); 12-Intake pressure regulator tank; 13-Second temperature sensor (T2); 14-First pressure sensor (P1); 15-Intake pressure regulating blower (F2); 16-Intake air storage tank; 17-Intake side exhaust switch valve (V3); 18-Exhaust main pipe; 19-Exhaust pressure regulator tank ; 20-Third temperature sensor (T3); 21-Second pressure sensor (P2); 22-Exhaust side electric control valve (V4); 23-Exhaust pressure regulating fan (F3); 24-Exhaust cooling pipe; 25-Exhaust cooling water regulating valve (V5); 26-Exhaust cooling water inlet; 27-Exhaust cooling water outlet; 28-Exhaust gas storage tank; 29-Exhaust side external discharge switch valve (V6); 30-Main controller; 31-High altitude operating condition preset table; 32-Intake air cooling controller (C1); 33-Intake air heating controller (C2); 34-Intake air pressure controller (C3); 35-Exhaust temperature controller (C4); 36-Exhaust pressure controller (C5). Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see Figure 1 The present invention provides the following technical solution: In this embodiment, engine 10 is used as the test object. An intake simulation pipeline is set on the intake side of engine 10, and an exhaust simulation pipeline is set on the exhaust side of engine 10.

[0024] like Figure 1As shown, the intake simulation piping is arranged as follows: Outside air is pressurized by the intake blower 2 (F1) at inlet 1 and then sent into the intake cooling pipe 3. Cooling water enters through inlet 5 and flows out through outlet 6, with the flow rate regulated by the intake cooling water regulating valve 4 (V1). The cooled air enters the heater volume 8-1, where temperature compensation is performed by the electric heating branch 8-2, and then it is supplied to the engine 10 through the intake main pipe 9.

[0025] To create a low-pressure environment, a pressure regulating bypass is led out from the main intake pipe 9. Along the flow direction, the following components are arranged in sequence: intake-side electric control valve 11 (V2), intake pressure stabilizing tank 12, intake pressure regulating fan 15 (F2), intake air storage tank 16, and intake-side exhaust valve 17 (V3). The pressure stabilizing tank 12 provides detection points for the second temperature sensor 13 (T2) and the first pressure sensor 14 (P1).

[0026] The exhaust-side processing path is as follows: the exhaust gas discharged from the engine 10 enters the exhaust pressure regulating tank 19 through the exhaust pipe 18. This tank not only weakens the exhaust pulsation but also houses the third temperature sensor 20 (T3) and the second pressure sensor 21 (P2). After the tank, the exhaust gas flows sequentially through the exhaust-side electric control valve 22 (V4), the exhaust pressure regulating fan 23 (F3), the exhaust cooling pipe 24, and the exhaust gas storage tank 28, and is finally discharged to the outside by the exhaust-side external discharge switch valve 29 (V6). The exhaust cooling water regulating valve 25 (V5) controls the amount of cooling water entering the exhaust cooling pipe 24.

[0027] like Figure 2 As shown, the control system adopts a hierarchical architecture. The main controller 30 is responsible for operating condition management, preset table reading and writing, and global scheduling. Five sub-controllers are set up below it: intake air cooling controller 32 (C1) adjusts V1 according to T1, intake air heating controller 33 (C2) adjusts electric heating branch 8-2 ​​according to T2, intake air pressure controller 34 (C3) coordinates the adjustment of F2 and V2 according to P1, exhaust temperature controller 35 (C4) adjusts V5 according to T3, and exhaust pressure controller 36 (C5) coordinates the adjustment of F3 and V4 according to P2. V3 and V6 are on-off type switching valves, which are switched on and off by the main controller 30 or the corresponding sub-controller according to the stage status and do not participate in continuous regulation.

[0028] The main controller 30 receives the target simulated altitude H and sensor signals of T1, T2, T3, P1 and P2, and is connected to the storage unit of the plateau working condition preset table 31. C1 adjusts V1 according to T1, C2 adjusts the electric heating branch 8-2 ​​according to T2, C3 adjusts F2 and V2 according to P1, C4 adjusts V5 according to T3, and C5 adjusts F3 and V4 according to P2.

[0029] V3 and V6 control the corresponding external discharge passages according to operational needs. As external discharge switching valves, V3 and V6 can be controlled by the main controller or the corresponding sub-controller according to the table calibration, preset start-up and operation maintenance status. They are not used as the main actuators for continuous pressure regulation.

[0030] like Figure 3 As shown, the plateau operating condition preset table 31 is a bridge connecting the table construction and calibration stage and the formal operation stage. The data in the table is organized according to the operating condition index, which includes at least four dimensions: target simulated altitude, engine model, calibration speed and calibration load. This refines the control parameters to specific engine models and operating conditions, avoiding the adaptation error caused by "one table for multiple uses".

[0031] For each operating condition index, the following information is stored in the preset table 31: Target parameters: target intake pressure, target intake temperature, target exhaust back pressure, and exhaust temperature limit; Theoretical initial values: F2 / F3 speed, V2 / V4 opening, V1 / V5 opening, and power of electric heating branch 8-2 ​​obtained based on thermodynamic and fluid dynamic estimation; Calibration stable value: stable value after static pre-calibration correction under engine off-state conditions; Exhaust side dynamic correction reference value: exhaust side actuator correction amount or absolute value obtained after low-load dynamic calibration; Criterion parameters: first allowable error, second allowable error, and their respective stable holding time.

[0032] After static pre-calibration is completed, the stable calibration values ​​are first written into the corresponding table entries. After low-load dynamic calibration is completed, the exhaust-side dynamic correction reference values ​​are supplemented or updated. During formal operation, the main controller 30 reads the target parameters and two types of preset parameters at once according to the index, providing a data basis for phased calls. If the target operating condition is located between two calibrated indices, the main controller 30 can use linear interpolation to calculate the preset parameters, or directly call the nearest neighbor table entry and perform feedback fine-tuning based on it.

[0033] like Figure 4 The core task of the table building and calibration stage is to solidify the parameters of the test bench's own characteristics and the exhaust side dynamic characteristics in two steps before the engine enters the formal test conditions.

[0034] The table setup and calibration phase includes: S101, theoretical estimation based on the target simulated altitude H; S102, generating initial preset table entries; S103, conducting device trial operation with engine 10 off; S104, collecting T1, T2, T3, P1, and P2; S105, calculating operating condition deviations; S106, determining whether the first criterion is met; S107, if not met, correcting the corresponding actuators from C1 to C5 and returning to data collection; S108, if met, recording stable parameters; S109, writing stable parameters into the plateau operating condition preset table 31.

[0035] In S101, the target intake pressure corresponding to the target simulated altitude H can be determined based on the standard atmospheric pressure relationship or a pre-stored altitude-pressure data table. The target intake temperature, target exhaust back pressure, and exhaust temperature limits can be determined based on the test specifications, engine model, and equipment allowable temperature.

[0036] In S102, the main controller 30 generates initial preset entries based on the target intake pressure, target intake temperature, target exhaust back pressure, and exhaust temperature limits. The theoretical initial values ​​include the speed of the intake pressure regulating fan 15 (F2), the speed of the exhaust pressure regulating fan 23 (F3), the opening degree of the intake-side electric control valve 11 (V2), the opening degree of the exhaust-side electric control valve 22 (V4), the opening degree of the intake cooling water regulating valve 4 (V1), the opening degree of the exhaust cooling water regulating valve 25 (V5), and the power of the electric heating branch 8-2.

[0037] In one implementation, the atmospheric pressure corresponding to the target altitude can be obtained from the standard atmospheric relationship or the altitude-pressure data table; the theoretical initial speed of the fan can be estimated based on the target pressure difference and reference operating conditions according to the fan similarity relationship; the theoretical initial opening of the electric control valve can be determined based on the target flow rate, the pressure difference before and after the valve, and the valve flow characteristic curve; the theoretical initial power of the electric heating branch 8-2 ​​and the theoretical initial opening of the cooling water regulating valve can be estimated based on the target temperature difference, mass flow rate, and heat exchange of the air or exhaust.

[0038] The aforementioned theoretical initial values ​​are the starting point for the trial operation of the device under engine-off conditions and are not used as the final control parameters for the formal operation phase. During the trial operation of the device, the main controller 30 corrects the theoretical initial values ​​based on feedback from T1, T2, T3, P1, and P2; when the deviation between the measured operating parameters and the target operating parameters meets the first criterion, the corrected stable parameters are written into the plateau operating condition preset table 31 as the calibration stable values.

[0039] In S103, the trial run of the device does not involve engine performance testing, but rather verifies whether the test bench itself can establish the intake pressure, intake temperature, exhaust back pressure, and exhaust temperature corresponding to the target altitude. At this time, the fans, valves, cooling water regulating valves, and electric heating branches on the intake and exhaust sides enter the preset state according to the theoretical initial values ​​in the initial preset table entries. The sensor feedback mainly reflects the comprehensive response of the test bench pipelines, pressure tank, heat exchange structure, and actuators.

[0040] In S107, the correction method can be determined based on the deviation direction and deviation amplitude. In this embodiment, when the intake pressure is too high, the speed of the intake pressure regulating fan 15 (F2) can be increased or the opening of the intake-side electric control valve 11 (V2) can be increased to enhance the suction effect of the intake pressure regulating branch; when the intake pressure is too low, the speed of F2 can be reduced or the opening of V2 can be decreased. When the intake temperature is too low, the power of the electric heating branch 8-2 ​​can be increased; when the intake temperature is too high, the opening of the intake cooling water regulating valve 4 (V1) can be increased or the power of the electric heating branch 8-2 ​​can be decreased. When the exhaust temperature is too high, the opening of the exhaust cooling water regulating valve 25 (V5) can be increased; when the exhaust back pressure deviates from the target range, it can be corrected by adjusting the speed of the exhaust pressure regulating fan 23 (F3) and the opening of the exhaust-side electric control valve 22 (V4).

[0041] In another implementation, the feedback correction adopts an incremental correction method. The main controller 30 determines the correction amount based on the direction and magnitude of the deviation between the target value and the measured value, and sends the correction amount to the corresponding sub-controller. Each correction amount is limited by the maximum adjustment step size. After correction, sensor data is re-acquired and the first criterion is judged again until the first criterion is met.

[0042] The first criterion includes at least the following: the detection values ​​of the first pressure sensor 14 (P1), the second temperature sensor 13 (T2), and the second pressure sensor 21 (P2) are within the allowable range during the calibration phase; the detection value of the third temperature sensor 20 (T3) does not exceed the exhaust temperature limit and remains stable for a first set time. The second criterion is used during the formal operation phase; its judgment object can be the same as the first criterion, but the second allowable error is smaller than the first allowable error. In one embodiment, the first pressure allowable error can be ±1.0 kPa to ±3.0 kPa, and the first temperature allowable error can be ±2℃ to ±5℃; the second pressure allowable error can be ±0.3 kPa to ±1.0 kPa, and the second temperature allowable error can be ±0.5℃ to ±1℃.

[0043] The first criterion is used to determine whether stable parameters have been formed for the current altitude gear and can be written into the high-altitude operating condition preset table 31. The second criterion is used to determine whether engine start is allowed and whether the target operating condition is maintained during the formal operation phase. The first and second criteria can use the same detection object, but their corresponding control phases and permissible errors are different. The first criterion emphasizes parameter availability and table establishment efficiency, while the second criterion emphasizes control accuracy during the formal operation phase, and the second permissible error is smaller than the first permissible error. The first and second criteria can use the same detection object, but their corresponding control phases are different. The first criterion is used to determine whether stable parameters can be written during the table establishment and calibration phase, and the second criterion is used to determine whether engine start is allowed and whether the target operating condition is maintained during the formal operation phase; the second permissible error is smaller than the first permissible error.

[0044] The fan speed, electric control valve opening, cooling water regulating valve opening, and electric heating branch power can all be adjusted within their respective rated ranges. To avoid frequent operation, the main controller or sub-controllers can be set with maximum adjustment step size, minimum action interval, and control dead zone; these limiting parameters can be adjusted according to engine model, altitude gear, or test item.

[0045] like Figure 5 As shown, the formal operation phase embodies the hierarchical control concept of "static reproduction first, then dynamic correction." The formal operation phase includes: S201, inputting the target simulated altitude H; S202, calling the corresponding preset table entries; S203, putting the actuator into the preset state; S204, collecting intake and exhaust environmental parameters; S205, determining whether the second criterion is met; S206, if not met, providing feedback for fine-tuning and returning to data collection; S207, allowing engine start after the second criterion is met and stabilized; S208, continuously collecting data during engine operation; S209, performing operational fine-tuning based on calling the preset table.

[0046] The pre-set start-up during the formal operation phase differs from re-searching for control parameters from an unknown state. The main controller 30 calls the calibrated stable values ​​that have already been established through table creation, allowing the actuators to first enter the vicinity of the target operating condition, and then uses the second criterion for accuracy judgment. When the second criterion is not met, the system does not re-establish a complete table, but instead performs small-range feedback fine-tuning near the calibrated stable values. This method utilizes the stable parameters obtained from table creation and calibration, and can adapt to actual disturbances before and after engine start-up.

[0047] During the formal operation phase, feedback fine-tuning is based on the calibration stability parameters in the preset table 31 for high-altitude operating conditions. When the feedback value is within the allowable range of the second criterion, each sub-controller maintains the current actuator state or performs maintenance fine-tuning; when the feedback value exceeds the allowable range of the second criterion, each sub-controller outputs an incremental correction amount according to the deviation direction and deviation amplitude. Feedback fine-tuning during the formal operation phase does not change the calibration stability values ​​already written into the preset table, unless the table creation and calibration process is re-entered.

[0048] This invention achieves a balance between "efficiency in table establishment and accuracy in operation" through differentiated criteria. The first criterion is used in the table establishment and calibration stage, and its first allowable error setting is relatively lenient. For example, the allowable error for intake pressure can be ±1.0 kPa to ±3.0 kPa, and the allowable error for intake temperature can be ±2℃ to ±5℃.

[0049] This design can shorten the calibration time per cycle and quickly generate usable entries. The second criterion is used during the formal operation phase, and its second permissible error is stricter than the first permissible error. For example, the permissible error for intake pressure can be ±0.3 kPa to ±1.0 kPa, and the permissible error for intake temperature can be ±0.5℃ to ±1℃. The stabilization holding times for the two criteria can also be configured separately. Typically, the second stabilization holding time is shorter than the first stabilization holding time to avoid excessively long engine start-up wait times.

[0050] In other embodiments, the plateau operating condition preset table 31 can be divided into sub-tables according to engine model, and each sub-table can be further subdivided according to altitude gear and speed-load matrix. For operating conditions that are not directly calibrated, the main controller 30 can perform bilinear interpolation in the speed dimension and load dimension to generate approximate preset parameters, thereby reducing the calibration workload.

[0051] In other implementations, the exhaust-side static pressure control during the static precalibration phase can be decoupled from the intake-side pressure control: first, an intake-side calibration stable value is independently established and locked, and then the exhaust-side passage is opened to establish an exhaust-side calibration stable value, so as to reduce the impact of the coupling between the two sides on the convergence speed.

[0052] Furthermore, each sub-controller can be independently configured with a control dead zone and minimum action interval. For example, when the P1 deviation is less than 0.1 kPa, C3 can pause the output of correction commands to avoid high-frequency vibration of the fan and valves. This dead zone parameter can be adaptively adjusted according to the altitude setting or engine model.

[0053] Working principle: S1, table initialization: Based on the target working condition index, establish the corresponding plateau working condition preset table (31) entries. The working condition index includes at least the target simulated altitude, engine model, calibration speed and calibration load, thereby binding the control parameters with the specific engine model and operating conditions.

[0054] S2. Theoretical estimation: Based on the target intake pressure, target intake temperature, target exhaust back pressure and exhaust temperature limits corresponding to the target simulated altitude, theoretical estimation is performed using standard atmospheric relations, fan similarity laws, valve flow characteristics and heat exchanger thermal balance relations to generate theoretical initial values ​​for each actuator, which serve as the starting point for subsequent calibration.

[0055] S3. Static pre-calibration: When the engine (10) is not running, the intake side actuator is set to the preset state according to the theoretical initial value. Based on the intake pressure feedback from the first pressure sensor (14), the intake temperature feedback from the second temperature sensor (13), and the exhaust side static pressure feedback from the second pressure sensor (21), the intake pressure regulating fan (15), the intake side electric control valve (11), the intake cooling water regulating valve (4), and the electric heating branch (8-2) are incrementally corrected. When the static working condition meets the first criterion, the corrected calibration stable value is written into the plateau working condition preset table (31) to realize the offline solidification of the static control parameters of the intake side and the exhaust side.

[0056] S4. Low-load dynamic calibration: Start the engine (10) to enter the predetermined low-load calibration condition. Based on the exhaust back pressure feedback from the second pressure sensor (21) and the exhaust temperature feedback from the third temperature sensor (20), dynamically correct the exhaust pressure regulating fan (23), the exhaust side electric control valve (22) and the exhaust cooling water regulating valve (25). When the dynamic condition meets the first criterion, the formed exhaust side dynamic correction benchmark value is added to the plateau condition preset table (31) to complete the offline solidification of the exhaust side dynamic control parameters.

[0057] S5. Static preset start-up: During formal operation, the main controller (30) calls the calibration stability value in the corresponding plateau working condition preset table (31) according to the target working condition index, so that each actuator directly enters the calibrated working state and shortens the environment establishment time.

[0058] S6. Low-load operation access: When the static parameters meet the second criterion, the engine (10) is allowed to enter the low-load operation state and the corresponding exhaust side dynamic correction reference value is called; if the static parameters do not meet the second criterion, a small range of feedback fine adjustment is performed near the calibrated stable value until the accuracy requirements are met.

[0059] S7. Dynamic fine-tuning and holding: The main controller (30) performs feedback fine-tuning based on the feedback from the second pressure sensor (21) and the third temperature sensor (20). When the dynamic parameters on the exhaust side meet the second criterion and are held for a set time, the formal test condition is entered. During the formal test, the calibration parameters in the high-altitude condition preset table (31) are continuously used as the reference for holding feedback fine-tuning, and the fine-tuning process does not change the calibration values ​​written in the preset table.

[0060] Specifically, for the same controlled parameter, the allowable error corresponding to the second criterion is less than the allowable error corresponding to the first criterion, thus balancing efficiency in the table building and calibration stage and ensuring accuracy in the formal operation stage.

[0061] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims and not by the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for simulating intake and exhaust control of an engine at high altitude, characterized in that, Includes the following steps: S1. Establish corresponding plateau working condition preset table (31) entries based on the target working condition index. The working condition index includes at least the target simulated altitude, engine model, calibration speed and calibration load. S2. Based on the target intake pressure, target intake temperature, target exhaust back pressure and exhaust temperature limit corresponding to the target simulated altitude, perform theoretical estimation to generate the theoretical initial value of the actuator; S3. Static pre-calibration is performed when the engine (10) is not started, so that the intake side actuator enters the preset state according to the theoretical initial value. Based on the intake pressure feedback of the first pressure sensor (14), the intake temperature feedback of the second temperature sensor (13), and the exhaust side static pressure feedback of the second pressure sensor (21), the intake pressure regulating fan (15), the intake side electric control valve (11), the intake cooling water regulating valve (4), and the electric heating branch (8-2) are corrected. When the static working condition meets the first criterion, the corrected calibration stable value is written into the plateau working condition preset table (31). S4. Start the engine (10) and enter the predetermined low load calibration condition. Based on the exhaust back pressure feedback from the second pressure sensor (21) and the exhaust temperature feedback from the third temperature sensor (20), dynamically correct the exhaust pressure regulating fan (23), the exhaust side electric control valve (22) and the exhaust cooling water regulating valve (25). When the dynamic condition meets the first criterion, the formed exhaust side dynamic correction reference value is added to the plateau condition preset table (31). S5. During formal operation, the main controller (30) calls the calibration stability value in the corresponding plateau working condition preset table (31) according to the target working condition index, so that each actuator enters the preset state. S6. When the static parameters meet the second criterion, the engine (10) is allowed to enter the low-load operation state and the corresponding exhaust side dynamic correction reference value is called. S7. The main controller (30) performs feedback fine-tuning based on the feedback from the second pressure sensor (21) and the third temperature sensor (20). When the dynamic working condition meets the second criterion and is maintained for a set time, it enters the formal test working condition and continues to perform maintenance feedback fine-tuning during the formal test. For the same controlled parameter, the permissible error corresponding to the second criterion is less than the permissible error corresponding to the first criterion.

2. The engine high-altitude intake and exhaust simulation control method according to claim 1, characterized in that: The plateau working condition preset table (31) includes at least: working condition index, target parameters, theoretical initial values, calibration stable values, exhaust side dynamic correction reference values ​​and criterion parameters; The target parameters include target intake pressure, target intake temperature, target exhaust back pressure, and exhaust temperature limit. The theoretical initial values ​​include the speed of the intake pressure regulating fan (15), the speed of the exhaust pressure regulating fan (23), the opening degree of the intake side electric control valve (11), the opening degree of the exhaust side electric control valve (22), the opening degree of the intake cooling water regulating valve (4), the opening degree of the exhaust cooling water regulating valve (25), and the power of the electric heating branch (8-2).

3. The engine high-altitude intake and exhaust simulation control method according to claim 1, characterized in that: During the static pre-calibration process, the main controller (30) determines the correction amount of the actuator based on the deviation direction and deviation amplitude between the target value and the feedback value, and uses an incremental method to correct the intake pressure regulating fan (15), the intake side electric control valve (11), the intake cooling water regulating valve (4) and the electric heating branch (8-2). Each correction is limited by the maximum adjustment step size.

4. The engine high-altitude intake and exhaust simulation control method according to claim 1, characterized in that: During the static pre-calibration process, only the calibrated stable values ​​of the intake pressure corresponding to the first pressure sensor (14), the intake temperature corresponding to the second temperature sensor (13), and the exhaust side static pressure corresponding to the second pressure sensor (21) are established. The third temperature sensor (20) is only used for status monitoring or safety monitoring.

5. The engine high-altitude intake and exhaust simulation control method according to claim 1, characterized in that: During the low-load dynamic calibration process, the main controller (30) performs joint correction on the exhaust pressure regulating fan (23), the exhaust side electric control valve (22) and the exhaust cooling water regulating valve (25) based on the feedback from the second pressure sensor (21) and the third temperature sensor (20) to form the exhaust side dynamic correction reference value.

6. The engine high-altitude intake and exhaust simulation control method according to claim 1, characterized in that: During the formal operation phase, the main controller (30) first calls the calibration stable value in the plateau operating condition preset table (31) to establish the target static operating condition, and then calls the exhaust side dynamic correction reference value to establish the target dynamic operating condition. The two phases are respectively based on the corresponding second criterion for feedback control.

7. The engine high-altitude intake and exhaust simulation control method according to claim 1, characterized in that: The first criterion includes a first allowable error and a first stable holding time; The second criterion includes a second allowable error and a second stable holding time; Among them, the second permissible error corresponding to the same controlled parameter is less than the first permissible error.

8. A high-altitude intake and exhaust simulation test bench for an engine, comprising an engine (10), characterized in that, It also includes an intake simulation pipeline disposed on the intake side of the engine (10) and an exhaust simulation pipeline disposed on the exhaust side of the engine (10); The intake simulation pipeline includes an intake blower (2), an intake cooling pipe (3), a heater (8) connected in sequence along the gas flow direction, and an intake main pipe (9) connected to the intake port of the engine (10). The intake cooling pipe (3) is connected to an intake cooling water regulating valve (4) for adjusting the flow rate of the cooling medium. The intake main pipe (9) is connected to an intake pressure regulating bypass. The intake pressure regulating bypass includes an intake side electric control valve (11), an intake pressure stabilizing tank (12), an intake pressure regulating fan (15), an intake gas storage tank (16), and an intake side exhaust switch valve (17) arranged sequentially along the gas flow direction. The intake pressure stabilizing tank (12) is equipped with a second temperature sensor (13) for detecting the intake temperature and a first pressure sensor (14) for detecting the intake pressure. The exhaust simulation pipeline includes an exhaust main pipe (18) connected to the exhaust port of the engine (10). The exhaust main pipe (18) is connected in sequence along the gas flow direction to an exhaust pressure stabilizing tank (19), an exhaust-side electric control valve (22), an exhaust pressure regulating fan (23), an exhaust cooling pipe (24), an exhaust gas storage tank (28), and an exhaust-side external discharge switch valve (29). The exhaust cooling pipe (24) is connected to an exhaust cooling water regulating valve (25) for adjusting the flow rate of the cooling medium. The exhaust pressure stabilizing tank (19) is equipped with a third temperature sensor (20) for detecting the exhaust temperature and a second pressure sensor (21) for detecting the exhaust pressure.

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