Engine supercharging transient response evaluation method and system

Abstract

The present application belongs to the technical field of engine turbocharging test, and discloses an engine supercharging transient response evaluation method and system. The method comprises the following steps: test preparation, working condition setting, transient excitation and data acquisition, calculation of rotational speed increment time, calculation of intake pressure build-up efficiency index, and two-dimensional diagnosis and evaluation. The present application effectively solves the technical problem that the existing evaluation parameters cannot distinguish the fundamental reasons for response delay, has the advantages of accurate positioning and strong guidance, and is particularly suitable for the research and development and optimization of supercharging systems of hydrogen fuel internal combustion engines and other harsh transient response requirements.

Description

Technical Field

[0001] This invention belongs to the field of engine turbocharger testing technology, and particularly relates to a method and system for evaluating the transient response of engine turbocharger. Background Technology

[0002] Turbocharging technology is a key technology for improving the power and economy of internal combustion engines while reducing emissions. However, traditional exhaust gas turbochargers generally suffer from turbo lag, meaning that when the engine load suddenly increases, the rotor speed cannot keep up instantly, resulting in insufficient intake air volume. To solve this problem, the electromechanical hybrid turbocharger (E-Turbo) has emerged, which actively assists rotor acceleration by integrating a high-speed electric motor, significantly improving transient response. With the development of next-generation power systems such as hydrogen fuel cell internal combustion engines, extremely high demands are placed on the transient response of the intake system, even requiring near-zero-delay air supply. However, existing transient response evaluation methods have significant limitations:

[0003] (1) Traditional acceleration parameters (such as the B parameter proposed by Karl Zinner) or improved comprehensive evaluation indicators (such as D) x These parameters are essentially lumped parameters. They treat the tested turbocharger as a "black box," coupling the rotor's mechanical acceleration process with the compressor's aerodynamic pressure build-up process, ultimately providing only a general evaluation of its quality.

[0004] (2) When the evaluation results show poor response, the existing methods cannot distinguish whether the root cause is at the "mechanical level" (such as excessive rotor rotational inertia or insufficient motor auxiliary torque) or the "aerodynamic level" (such as low aerodynamic efficiency of the compressor under transient conditions or approaching the surge boundary).

[0005] (3) Although existing advanced test benches have achieved precise control of compressor speed and simulation of thermal effects, they mainly focus on the platform construction itself and lack diagnostic evaluation theory for the inherent performance bottlenecks of electromechanical composite turbochargers. Therefore, it is necessary to design a new method that can perform two-dimensional diagnostic evaluation of the transient response performance of electromechanical composite turbochargers in order to accurately locate performance bottlenecks and guide optimization design. Summary of the Invention

[0006] To overcome the problems existing in related technologies, the present invention discloses an engine turbocharger transient response evaluation method and system; specifically, it relates to an electromechanical composite turbocharger transient response evaluation method and system that comprehensively considers speed response and intake pressure build-up efficiency, thereby accurately locating its performance bottleneck and guiding optimization design.

[0007] The technical solution is as follows: A method for evaluating the transient response of engine turbocharger. This method achieves decoupling characterization of the contributions of aerodynamic drive and electric drive in an electromechanical composite turbocharger by independently controlling the airflow energy input at the turbine end and the electric power input at the motor end; the speed increment time reflects the coupling characteristics of turbocharger inertia and drive capability; the intake pressure build-up efficiency index reflects the compressor's aerodynamic work capacity and compressor charging characteristics; a two-dimensional diagnostic evaluation method distinguishes the transient response differences under different drive modes, thereby achieving a quantitative evaluation of the turbocharger's electric auxiliary effect; the method specifically includes the following steps:

[0008] S1, Test preparation: The electromechanical composite turbocharger to be tested is installed on an electromechanical composite turbocharger test bench that independently controls and measures the motor input power and hot airflow energy.

[0009] S2, Operating Condition Setting, sets the initial steady-state operating point for the transient process. and the target final steady-state operating point ;

[0010] S3, transient excitation and data acquisition, at the initial moment An airflow energy input is applied to the turbine end, while a preset electrical power assist is applied to the motor end. The instantaneous rotor speed is recorded synchronously using the data synchronization acquisition system. and compressor outlet instantaneous pressure ;

[0011] S4, calculate the rotational speed increment time;

[0012] S5, calculate the intake pressure establishment efficiency index;

[0013] S6, Two-dimensional diagnostic evaluation.

[0014] In step S1, the electromechanical composite turbocharger test bench uses a motor to directly drive the compressor and is equipped with a turbine backplate temperature simulator to decouple the compressor from the turbine and simulate the turbine heat transfer effect.

[0015] In step S2, the operating point Corresponding speed and boost pressure Operating point Corresponding speed and boost pressure Under the set transient operating conditions, a step or ramp-type thermal airflow energy input and a preset electric power assistance are applied simultaneously to trigger the transient acceleration process.

[0016] In step S3, the instantaneous rotor speed is obtained using a data synchronization acquisition system equipped with a high-frequency response sensor. and compressor outlet instantaneous pressure The signal time deviation is less than 1ms, and the sampling frequency is not lower than 1kHz.

[0017] In step S4, the rotational speed increment time is calculated. Based on the instantaneous rotational speed of the rotor Calculate the rotational speed increment from the target of 10%. Change to 90% of the target increment Time elapsed The expression is:

[0018]

[0019] In the formula, To achieve the target speed increase of 10% At that moment, To achieve the target increment of 90% of the rotational speed At that moment.

[0020] In step S5, the calculation of the intake pressure build-up efficiency index includes: based on the instantaneous pressure at the compressor outlet. and rotor instantaneous speed Calculate the dimensionless intake pressure build-up efficiency index This characterizes the aerodynamic efficiency of a compressor in converting rotational kinetic energy into pressure energy.

[0021] First, based on the instantaneous pressure at the compressor outlet. Calculate the pressure from a 10% target increment Change to 90% of the target increment Time elapsed ;in, To achieve the target increment of 10% under pressure At that moment, To achieve a 90% target increment under pressure The moment;

[0022] Then, the efficiency index is defined by the ratio of the speed increment time to the pressure increment time, and the expression is:

[0023] .

[0024] In step S6, the two-dimensional diagnostic evaluation includes: using rotational speed increments over time. Establish efficiency indicators based on intake pressure Together, they form a two-dimensional evaluation coordinate system. The transient response performance of the electromechanical composite turbocharger under test is located at a specific point in this two-dimensional evaluation coordinate system, and a comprehensive performance diagnosis is performed based on the quadrant in which the specific point is located.

[0025] Furthermore, the transient response performance of the electromechanical composite turbocharger under test is located at a specific point in the two-dimensional evaluation coordinate system, and a comprehensive performance diagnosis is performed based on the quadrant in which the specific point is located, including:

[0026] If the speed increment time Less than the preset threshold and intake pressure build-up efficiency index If the value exceeds the preset threshold, it is judged as having excellent overall performance;

[0027] If the speed increment time The intake pressure build-up efficiency index is greater than the preset threshold. If the value exceeds the preset threshold, it is determined that the rotor moment of inertia is too large or the motor auxiliary power is insufficient.

[0028] If the speed increment time Less than the preset threshold and intake pressure build-up efficiency index If the value is less than a preset threshold, it is determined that the compressor's transient aerodynamic performance is poor.

[0029] If the speed increment time The intake pressure build-up efficiency index is greater than the preset threshold. If the value is less than the preset threshold, it is judged as poor overall performance.

[0030] The preset threshold is obtained through test results of a benchmark electromechanical composite turbocharger under the same transient operating conditions, including reference values ​​for speed increment time and intake pressure build-up efficiency index, or the reference values ​​multiplied by a preset correction coefficient. The preset threshold is used to determine the performance boundary in the two-dimensional evaluation coordinate system.

[0031] Another objective of this invention is to provide an engine boost transient response evaluation system, which implements the engine boost transient response evaluation method. The system includes: an electromechanical composite turbocharger test system, a speed sensor, a pressure sensor, a data synchronous acquisition system, and a central processing unit.

[0032] The speed sensor is mounted on the shaft end of the electromechanical composite turbocharger under test and is a component of the compressor speed and back disk parameter measurement system. The electromechanical composite turbocharger under test is installed on the electromechanical composite turbocharger test system.

[0033] The pressure sensor is a component of the compressor outlet parameter measurement system;

[0034] The data synchronous acquisition system is configured on the electromechanical composite turbocharger test system and is connected to the central processing unit via signal;

[0035] The central processing unit is connected to the electromechanical composite turbocharger test system, speed sensor, pressure sensor, and data synchronous acquisition system. It is used to perform calculations of speed increment time, calculations of intake pressure to establish efficiency indicators, and two-dimensional diagnostic evaluation.

[0036] Combining all the above technical solutions, the beneficial effects of this invention are as follows:

[0037] This invention includes: test preparation, operating condition setting, application of combined electrothermal transient excitation, synchronous data acquisition, and calculation of rotational speed increment time. Establish efficiency indicators with intake pressure This invention decouples the mechanical / electrical acceleration capability of the turbocharger from the aerodynamic performance of the compressor, effectively solving the technical problem that existing evaluation parameters cannot distinguish the root cause of response lag. It has the advantages of accurate positioning and strong guidance, and is particularly suitable for the research and optimization of turbocharged systems such as hydrogen fuel cell internal combustion engines that have stringent requirements for transient response.

[0038] Compared to existing technologies, the dual-dimensional diagnosis of this invention provides richer information: For the first time, this invention decouples the complex transient response process into two dimensions: rotational speed response (characterizing mechanical / electrical performance) and pressure build-up efficiency (characterizing aerodynamic performance). The evaluation result changes from a single numerical value to a two-dimensional coordinate point, greatly improving the amount of information and diagnostic value.

[0039] This invention precisely pinpoints performance bottlenecks: by analyzing the position of evaluation points in a two-dimensional coordinate system, the root cause of poor response can be clearly identified. For example, slow speed response but high pressure efficiency indicates that the bottleneck lies in rotor inertia or motor power; conversely, fast speed response but low pressure efficiency indicates that the problem lies in the aerodynamic design of the compressor, which may be approaching the surge boundary in transient conditions.

[0040] This invention is specifically designed for new technologies and has strong applicability: it is designed specifically for electromechanical composite turbochargers that include electrical energy input, perfectly matching their working principle. It is particularly suitable for cutting-edge fields such as hydrogen fuel cell engines and high-performance hybrid systems where extreme transient response is required.

[0041] This invention effectively guides optimized design: diagnostic evaluation results provide researchers with clear optimization directions, avoiding blind trial-and-error development. For example, if the problem is diagnosed as aerodynamic, resources should be concentrated on CFD optimization; if the problem is diagnosed as inertia, efforts should be focused on lightweight rotor materials and structural design.

[0042] The engine boost transient response evaluation method provided by this invention defines the engine speed increment time. Establish efficiency indicators based on intake pressure This invention constructs a two-dimensional diagnostic evaluation system, enabling quantitative and visual analysis of the transient performance of electromechanical composite turbochargers. This method can quickly identify the influence of rotor inertia, motor auxiliary power, and compressor aerodynamic performance on transient response during the turbocharger development stage, thus providing clear directions for rotor lightweight design, motor power matching, and aerodynamic structure optimization. Compared to traditional methods relying on whole-engine road testing or experience-based judgment, this invention can significantly shorten the turbocharger matching cycle, improve engine transient combustion response performance, and reduce development costs and testing energy consumption, demonstrating clear engineering promotion value and industrial application prospects.

[0043] Existing transient evaluation methods for turbochargers mostly focus on single-index analysis or rely on empirical judgment based on whole-machine test results. They lack a technical solution that can simultaneously quantify rotor acceleration capability and pressure build-up efficiency under electromechanical decoupling conditions and perform system diagnosis through a unified evaluation coordinate system. This invention, by constructing a benchmark model calibration system and a two-dimensional performance evaluation model, achieves structured analysis and zonal determination of turbocharger transient response performance, forming a repeatable, comparable, and scalable evaluation methodology system. This demonstrates significant innovation in the field of transient performance evaluation of electromechanical hybrid turbochargers.

[0044] In the design of turbocharger systems for hydrogen fuel cell internal combustion engines and high-dynamic-response engines, a long-standing technical challenge has been the difficulty in distinguishing the contribution ratios of rotor inertia, motor auxiliary power, and compressor transient aerodynamic performance to the overall response. Traditional methods struggle to provide quantifiable evaluation indicators for these components. This invention addresses this issue by synchronously acquiring speed and pressure signals at high frequency and introducing a mechanism defined based on response time. and The index enables the decomposition and quantitative characterization of the transient response process, thereby effectively solving the aforementioned long-standing engineering and technical problems.

[0045] Traditional views generally hold that the transient response of a turbocharger is mainly determined by the aerodynamic performance at the turbine end, while neglecting the significant impact of motor auxiliary power and rotor inertia on dynamic performance. This invention, through an electromechanical decoupling test bench structure, turbine backplate temperature simulation technology, and a two-dimensional diagnostic evaluation method, reveals the coupling relationship between mechanical inertia, motor power input, and aerodynamic efficiency. It overcomes the technical limitations of evaluating transient performance solely from an aerodynamic perspective, achieving a systematic and comprehensive analysis of the transient performance of electromechanical composite turbochargers. Attached Figure Description

[0046] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure;

[0047] Figure 1 This is a flowchart of the engine boost transient response evaluation method provided in an embodiment of the present invention;

[0048] Figure 2 This is a schematic diagram of the engine boost transient response evaluation method provided in an embodiment of the present invention;

[0049] Figure 3 This is a schematic diagram of a two-dimensional diagnostic evaluation coordinate system provided in an embodiment of the present invention. Detailed Implementation

[0050] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0051] The innovation of this invention lies in its proposal of a method and system for evaluating the transient response of engine turbochargers. By constructing a two-dimensional evaluation model composed of efficiency indices based on the speed increment time and intake pressure, it achieves comprehensive judgment and zonal diagnosis of the transient dynamic characteristics of electromechanical composite turbochargers. This technology can simultaneously reflect rotational inertia characteristics and transient aerodynamic efficiency, overcoming the shortcomings of traditional single-index evaluation methods that cannot comprehensively characterize dynamic performance.

[0052] Example 1: An engine turbocharger transient response evaluation system, comprising: an electromechanical composite turbocharger test system, a speed sensor, a pressure sensor, a data synchronous acquisition system, and a central processing unit;

[0053] The speed sensor is mounted on the shaft end of the electromechanical composite turbocharger under test and is a component of the compressor speed and back disk parameter measurement system. The electromechanical composite turbocharger under test is installed on the electromechanical composite turbocharger test system.

[0054] The pressure sensor is a component of the compressor outlet parameter measurement system;

[0055] The data synchronous acquisition system is configured on the electromechanical composite turbocharger test system and is connected to the central processing unit via signal;

[0056] The central processing unit is connected to the electromechanical composite turbocharger test system, speed sensor, pressure sensor, and data synchronous acquisition system. It is used to perform calculations of speed increment time, calculations of intake pressure to establish efficiency indicators, and two-dimensional diagnostic evaluation.

[0057] Example 2, as Figure 1As shown, the engine turbocharger transient response evaluation method provided in this embodiment of the invention achieves decoupling characterization of the contributions of aerodynamic drive and electric drive in an electromechanical composite turbocharger by independently controlling the airflow energy input at the turbine end and the electric power input at the motor end; the speed increment time reflects the coupling characteristics of turbocharger inertia and drive capability; the intake pressure build-up efficiency index reflects the compressor's aerodynamic work capacity and compressor charging characteristics; the two-dimensional diagnostic evaluation method distinguishes the transient response differences under different drive modes, thereby achieving a quantitative evaluation of the turbocharger's electric auxiliary effect; specifically, it includes the following steps:

[0058] S1, Test preparation: The electromechanical composite turbocharger to be tested is installed on an electromechanical composite turbocharger test bench that independently controls and measures the motor input power and hot airflow energy.

[0059] The electromechanical composite turbocharger test bench is equipped with a speed sensor, a pressure sensor, a data synchronous acquisition system, and a central processing unit.

[0060] S2, Operating Condition Setting, sets the initial steady-state operating point for the transient process. and the target final steady-state operating point ;

[0061] Operating point Corresponding speed and boost pressure Operating point Corresponding speed and boost pressure For example, under the given transient operating conditions (from the initial steady-state operating point) To the target final steady-state operating point Simultaneously, a step or ramp-type thermal airflow energy input and a preset electric power assist are applied to trigger a transient acceleration process;

[0062] S3, transient excitation and data acquisition, at the initial moment An airflow energy input is applied to the turbine end, while a preset electrical power assist is applied to the motor end. The instantaneous rotor speed is recorded synchronously using the data synchronization acquisition system. and compressor outlet instantaneous pressure ;

[0063] S4, calculate the rotational speed increment time;

[0064] Based on the instantaneous speed of the rotor Calculate the rotational speed increment time This characterizes the system's comprehensive mechanical and electrical acceleration capabilities;

[0065] S5, calculate the intake pressure establishment efficiency index;

[0066] Based on the instantaneous pressure at the compressor outlet and rotor instantaneous speed Calculate the dimensionless intake pressure build-up efficiency index This characterizes the aerodynamic efficiency of a compressor in converting rotational kinetic energy into pressure energy.

[0067] S6, Two-dimensional diagnostic evaluation;

[0068] Incremental speed over time Establish efficiency indicators based on intake pressure Together, they form a two-dimensional evaluation coordinate system. The transient response performance point of the electromechanical composite turbocharger under test is located at a specific point in this two-dimensional evaluation coordinate system, and a comprehensive performance diagnosis is performed based on the quadrant in which the specific point is located. This enables the location of the transient response performance point of the tested object to diagnose performance bottlenecks.

[0069] In step S1, the test bench uses a motor to directly drive the compressor and is equipped with a turbine backplate temperature simulator to decouple the compressor from the simulated turbine heat transfer effect.

[0070] In step S3, a data synchronization acquisition system equipped with a high-frequency response sensor is used to ensure the instantaneous rotor speed. and compressor outlet instantaneous pressure The instantaneous rotor speed is recorded synchronously with a signal time deviation of less than 1ms and a sampling frequency of not less than 1kHz. and compressor outlet instantaneous pressure .

[0071] In step S4, the rotational speed increment time The definition of is: ;in, To achieve the target speed increase of 10% At that moment, To achieve the target increment of 90% of the rotational speed At that moment.

[0072] Specifically, calculate the rotational speed increment time. Based on the instantaneous rotational speed of the rotor Calculate the rotational speed increment from the target of 10%. Change to 90% of the target increment The time of the speed increment This indicator characterizes the system's overall mechanical and electrical acceleration capabilities.

[0073] In step S5, the intake pressure build-up efficiency index The calculation formula is: ;in, ; To achieve the target increment of 10% under pressure At that moment, To achieve a 90% target increment under pressure At that moment.

[0074] Specifically, calculate the intake pressure build-up efficiency index. First, based on the instantaneous pressure at the compressor outlet... The calculation pressure is increased from the target increment of 10%. Change to 90% of the target increment The time of increased stress experienced Then, the efficiency index is defined by the ratio of the speed increment time to the pressure increment time, i.e. This index characterizes the aerodynamic efficiency of the compressor during transient processes.

[0075] In step S6, the transient response performance point of the electromechanical composite turbocharger under test is located at a specific point in the two-dimensional evaluation coordinate system, and the quadrant in which the specific point is located is determined according to... Figure 3 As shown, a comprehensive performance diagnosis is performed, including:

[0076] If the speed increment time Less than the preset threshold and intake pressure build-up efficiency index If the value exceeds the preset threshold, it is judged as having excellent overall performance;

[0077] If the speed increment time The intake pressure build-up efficiency index is greater than the preset threshold. If the value exceeds the preset threshold, it is determined that the rotor moment of inertia is too large or the motor auxiliary power is insufficient.

[0078] If the speed increment time Less than the preset threshold and intake pressure build-up efficiency index If the value is less than a preset threshold, it is determined that the compressor's transient aerodynamic performance is poor.

[0079] If the speed increment time The intake pressure build-up efficiency index is greater than the preset threshold. If the value is less than the preset threshold, it is judged as poor overall performance.

[0080] The preset threshold is obtained through test results of a benchmark electromechanical composite turbocharger under the same transient operating conditions, including reference values ​​for speed increment time and intake pressure build-up efficiency index, or the reference values ​​multiplied by a preset correction coefficient. The preset threshold is used to determine the performance boundary in the two-dimensional evaluation coordinate system.

[0081] This method can be applied to guide rotor lightweighting, motor selection, and aerodynamic optimization in applications such as hydrogen fuel cell internal combustion engine turbochargers.

[0082] Application Example. Taking an electromechanical hybrid turbocharger for a 2.0L hydrogen fuel cell internal combustion engine as an example, the transient response performance is evaluated using the method of this invention. For example... Figure 2 As shown, the engine boost transient response evaluation method provided in this embodiment of the invention includes:

[0083] Step 1: Test Preparation; Install the electromechanical composite turbocharger on a high-speed hot gas test bench. The test bench should have the following features: a hot gas source with precisely controllable temperature, pressure, and flow rate to simulate engine exhaust; and a programmable high-power power supply to drive the turbocharger motor and accurately record instantaneous power. Sensor Configuration: Install an eddy current speed sensor (response frequency > 10kHz) at the end of the electromechanical composite turbocharger shaft; install a high-frequency dynamic pressure sensor (response frequency > 2kHz) in the outlet pipe of the compressor outlet pressure regulating chamber; connect all sensor signals to a high-speed data synchronization acquisition system from NI (National Instruments). The data synchronization acquisition system should be set to a synchronization acquisition frequency of 5kHz.

[0084] Step 2: Operating Condition Setting: Set the start and end conditions for the transient test.

[0085] Initial operating condition Rotational speed The compressor pressure ratio is 1.2.

[0086] Final condition Target speed The corresponding pressure ratio is 2.5.

[0087] Step 3: Transient excitation;

[0088] exist At any given moment, the test bench control system executes two actions simultaneously:

[0089] Quickly open the hot gas source control valve so that the exhaust gas energy supplied to the turbine reaches the target value within 20ms.

[0090] Apply 3kW of auxiliary power to the turbocharger motor.

[0091] Step 4: Data Acquisition; The data acquisition system begins synchronously recording the instantaneous rotor speed at a frequency of 5kHz. and compressor outlet instantaneous pressure Over time The curve showing the change.

[0092] Step 5: Calculate the rotational speed increment time The instantaneous rotor speed collected From the data, find the following two time points:

[0093] The moment when the engine speed reaches 50000 + 0.1 * (180000 - 50000) = 63000 rpm.

[0094] The moment when the engine speed reaches 50000 + 0.9 * (180000 - 50000) = 167000 rpm.

[0095] Measured Then the rotational speed increment time The smaller this value, the faster the rotor accelerates.

[0096] Step 6: Calculate the intake pressure establishment efficiency index ;

[0097] The instantaneous pressure at the compressor outlet was collected. The following two time points were found in the data (pressure unit is bar, absolute pressure):

[0098] Initial pressure The pressure finally subsided. .

[0099] The moment when the pressure reaches 1.2 + 0.1 * (2.5 - 1.2) = 1.33 bar.

[0100] The moment when the pressure reaches 1.2 + 0.9 * (2.5 - 1.2) = 2.37 bar.

[0101] Measured Pressure increment time .

[0102] Intake pressure build-up efficiency index .

[0103] A value greater than 1 indicates that the relative speed at which pressure is built up is faster than the relative speed at which rotational speed is built up, suggesting that the compressor has good aerodynamic performance during this transient process.

[0104] Step 7: Two-dimensional diagnostic evaluation;

[0105] The evaluation result will be incremented by rotational speed and time. Intake pressure build-up efficiency index Plotted in a two-dimensional diagnostic coordinate system (e.g.) Figure 3 As shown, the X-axis is The Y-axis is This point is located in the ideal region where the response is fast and the aerodynamic efficiency is high.

[0106] Comparative Experiment 1.

[0107] Replace the turbine impeller with one whose moment of inertia increases by 20%, and repeat the above experiment. Possible results: Rotational speed increment time. Pressure increment time Intake pressure build-up efficiency index At this point, the intake pressure build-up efficiency index Basically unchanged, but the time for speed increment The value increases significantly, and the evaluation point shifts to the right. Conclusion: The transient response deteriorates, and the bottleneck lies in the rotational inertia.

[0108] Comparative Experiment 2.

[0109] Based on the original turbocharger, the compressor blades are modified to bring them closer to the surge boundary. Possible result: Speed ​​increment time. Pressure increment time Intake pressure build-up efficiency index At this point, the rotational speed increment time Unchanged, but pressure increment time Significantly increased, intake pressure build-up efficiency index If the value is less than 1, the evaluation point shifts downwards. Conclusion: The transient response deteriorates, and the bottleneck lies in the transient aerodynamic performance of the compressor.

[0110] As can be seen from the above embodiments, the method of the present invention can clearly and quantitatively diagnose the root causes affecting the transient response of electromechanical composite turbochargers, providing unprecedentedly accurate guidance for product iteration and development.

[0111] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention and within the spirit and principles of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for evaluating the transient response of engine boost, characterized in that, This method achieves decoupled characterization of the aerodynamic and electric drive contributions of the electromechanical composite turbocharger by independently controlling the airflow energy input at the turbine end and the electric power input at the motor end; the speed increment time reflects the coupling characteristics of the turbocharger's inertia and drive capability; the intake pressure build-up efficiency index reflects the compressor's aerodynamic work capacity and compressor charging characteristics; and the two-dimensional diagnostic evaluation method distinguishes the transient response differences under different drive modes, thereby achieving a quantitative evaluation of the turbocharger's electric auxiliary effect. Specifically, the following steps are included: S1, Test preparation: The electromechanical composite turbocharger to be tested is installed on an electromechanical composite turbocharger test bench that independently controls and measures the motor input power and hot airflow energy. S2, Operating Condition Setting, sets the initial steady-state operating point for the transient process. and the target final steady-state operating point ; S3, transient excitation and data acquisition, at the initial moment An airflow energy input is applied to the turbine end, while a preset electrical power assist is applied to the motor end. The instantaneous rotor speed is recorded synchronously using a data synchronization acquisition system. and compressor outlet instantaneous pressure ; S4, calculate the rotational speed increment time; In step S4, the rotational speed increment time is calculated. According to the instantaneous rotational speed of the rotor Calculate the rotational speed increment from the target of 10%. Change to 90% of the target increment The time of the speed increment The expression is: ； In the formula, To achieve the target speed increase of 10% At that moment, To achieve the target increment of 90% of the rotational speed The moment; S5, calculate the intake pressure establishment efficiency index; In step S5, the inlet pressure build-up efficiency index is calculated, including: based on the instantaneous pressure at the compressor outlet. and the instantaneous speed of the rotor Calculate the dimensionless intake pressure build-up efficiency index This characterizes the aerodynamic efficiency of a compressor in converting rotational kinetic energy into pressure energy. S6, Two-dimensional diagnostic evaluation; In step S6, the two-dimensional diagnostic evaluation includes: using rotational speed increments over time. Establish efficiency indicators based on intake pressure Together, they form a two-dimensional evaluation coordinate system. The transient response performance of the electromechanical composite turbocharger under test is located at a specific point in the two-dimensional evaluation coordinate system, and a comprehensive performance diagnosis is performed based on the quadrant in which the specific point is located.

2. The engine boost transient response evaluation method according to claim 1, characterized in that, In step S1, the electromechanical composite turbocharger test bench uses a motor to directly drive the compressor and is equipped with a turbine backplate temperature simulator to decouple the compressor from the turbine and simulate the turbine heat transfer effect.

3. The engine boost transient response evaluation method according to claim 1, characterized in that, In step S2, the operating point Corresponding speed and boost pressure Operating point Corresponding speed and boost pressure Under the set transient operating conditions, a step or ramp-type thermal airflow energy input and a preset electric power assistance are applied simultaneously to trigger the transient acceleration process.

4. The engine boost transient response evaluation method according to claim 3, characterized in that, In step S3, the instantaneous rotational speed of the rotor is obtained using the data synchronization acquisition system equipped with a high-frequency response sensor. and the instantaneous pressure at the compressor outlet The signal time deviation is less than 1ms, and the sampling frequency is not lower than 1kHz.

5. The engine boost transient response evaluation method according to claim 4, characterized in that, Calculate the dimensionless intake pressure build-up efficiency index Includes the following steps: First, based on the instantaneous pressure at the compressor outlet... Calculate the pressure from a 10% target increment Change to 90% of the target increment Time elapsed ;in, To achieve the target increment of 10% under pressure At that moment, To achieve a 90% target increment under pressure The moment; Then, through the rotational speed increment time With pressure increment time The ratio of intake pressure to efficiency index is used to define the efficiency index. The expression is: 。 6. The engine boost transient response evaluation method according to claim 5, characterized in that, The transient response performance of the electromechanical composite turbocharger under test is located at a specific point in the two-dimensional evaluation coordinate system, and a comprehensive performance diagnosis is performed based on the quadrant in which the specific point is located, including: If the speed increment time Less than the preset threshold and intake pressure build-up efficiency index If the value exceeds the preset threshold, it is judged as having excellent overall performance; If the speed increment time The intake pressure build-up efficiency index is greater than the preset threshold. If the value exceeds the preset threshold, it is determined that the rotor moment of inertia is too large or the motor auxiliary power is insufficient. If the speed increment time Less than the preset threshold and intake pressure build-up efficiency index If the value is less than a preset threshold, it is determined that the compressor's transient aerodynamic performance is poor. If the speed increment time The intake pressure build-up efficiency index is greater than the preset threshold. If the value is less than the preset threshold, it is determined to be poor overall performance; The preset threshold is obtained through test results of a benchmark electromechanical composite turbocharger under the same transient operating conditions, including reference values ​​for speed increment time and intake pressure build-up efficiency index, or the reference values ​​multiplied by a preset correction coefficient. The preset threshold is used to determine the performance boundary in the two-dimensional evaluation coordinate system.

7. An engine boost transient response evaluation system, characterized in that, The system implements the engine boost transient response evaluation method as described in any one of claims 1-6. The system includes: an electromechanical composite turbocharger test system, a speed sensor, a pressure sensor, a data synchronous acquisition system, and a central processing unit. The speed sensor is mounted on the shaft end of the electromechanical composite turbocharger under test and is a component of the compressor speed and back disk parameter measurement system. The electromechanical composite turbocharger under test is installed on the electromechanical composite turbocharger test system. The pressure sensor is a component of the compressor outlet parameter measurement system; The data synchronous acquisition system is configured on the electromechanical composite turbocharger test system and is connected to the central processing unit via a signal. The central processing unit is connected to the electromechanical composite turbocharger test system, the speed sensor, the pressure sensor, and the data synchronous acquisition system, and is used to perform calculations of speed increment time, calculations of intake pressure to establish efficiency indicators, and two-dimensional diagnostic evaluation.

Images