Engine emission digital design system and method based on virtual whole vehicle

Abstract

According to the engine emission digital design system and method based on the virtual whole vehicle, the engine, the temperature control loop, the dynamometer and the emission analysis module are arranged on the bench subsystem, multiple circulation working conditions are pre-stored through the circulation working condition model in the control subsystem, and the main control model calls the target circulation working condition according to the design requirement; the driving control model simulates a vehicle driving state; obtaining a road resistance curve through a road resistance model; the engine compartment temperature control model controls the temperature control loop to realize temperature control; the engine working condition model controls the engine to work under the target engine working condition; the emission analysis module receives emission of an engine and analyzes emission components, and the master control model receives the emission components and judges whether the current emission of the engine reaches the standard or not. According to the scheme, engine emission design development under the condition that no physical whole vehicle exists can be achieved, the whole vehicle development period is greatly shortened, the development efficiency is improved, and the development cost is saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicle engineering, in particular to an engine emission digital design system and method based on a virtual whole vehicle. BACKGROUND

[0002] Currently, the automobile industry is facing the dual challenges of rapid iteration of emission technology and reconstruction of development mode. The increasingly complex emission control technology, such as coordinated control of multiple power systems, lean energy management system, and deep integration of control software and hardware, has led to an increase in the difficulty of emission development; at the same time, the regulatory requirements are becoming more stringent, and the expansion of multi-dimensional emission test cycles and test environments, especially the need for hybrid electric vehicles to complete WLTC (Worldwide Harmonized Light Vehicles Test Cycle) tests in power consumption mode and power preservation mode, has led to a dramatic increase in the workload of emission development.

[0003] Currently, the industry's emission development is completed on a whole vehicle emission dynamometer with a physical whole vehicle, specifically, the test vehicle is placed on the whole vehicle emission dynamometer in the emission environment test chamber, and different driving test cycles are run by loading the whole vehicle test mass and road resistance to complete the emission development. In this way, emission development is completely dependent on the whole vehicle, and when a newly developed vehicle model does not have a prototype or the prototype is not fully functional, emission development work cannot be carried out; in addition, emission development relies on the dynamometer and each emission test requires more than 8 hours of soaking time to fully cool the engine and emission aftertreatment system. Based on the above prior art, there is still room for improvement in the engine emission design scheme. SUMMARY

[0004] The present application aims to provide an engine emission digital design system and method based on a virtual whole vehicle, which is used to complete the engine emission development and design of a newly developed vehicle model without a physical whole vehicle

[0005] In a first aspect, the technical solution of the present application provides an engine emission digital design system based on a virtual whole vehicle, comprising a test bench subsystem and a control subsystem, wherein:

[0006] The test bench subsystem comprises a test bench and an engine, a temperature control loop, a dynamometer and an emission analysis module arranged on the test bench; the dynamometer receives the torque output by the engine, and the emission analysis module receives the emissions of the engine;

[0007] The control subsystem comprises a master control model, a cycle working condition model, a driving control model, a road resistance model, an engine cabin temperature control model and an engine working condition model; the cycle working condition model pre-stores multiple cycle working conditions, and the master control model calls a target cycle working condition according to design requirements; the driving control model simulates a vehicle driving state; the road resistance model obtains a road resistance curve based on vehicle parameter input, including vehicle mass, road resistance coefficient, windward area and tire radius; the engine cabin temperature control model simulates a target temperature rise curve of engine cooling medium and a target temperature of an engine cabin in a target cycle working condition based on engine working condition heat dissipation characteristics, and controls a temperature control loop to realize temperature control; the optimal target engine working condition corresponding to the target cycle working condition is simulated based on vehicle fuel consumption optimization and energy balance criteria, and the engine working condition model controls the engine to work in the target engine working condition; the emission analysis module receives emissions of the engine and analyzes emission components, and the master control model receives the emission components to determine whether the current engine emissions meet standards.

[0008] Preferably, in some schemes, the virtual vehicle-based engine emission digital design system further comprises a gearbox arranged on the test bench, and the gearbox is arranged between the engine and the dynamometer.

[0009] Preferably, in some schemes, the virtual vehicle-based engine emission digital design system further comprises a high-voltage battery model arranged on the test bench, and a power output end of the high-voltage battery model is connected with the gearbox.

[0010] The driving control model in the control subsystem is further used to calculate battery working parameters of the high-voltage battery model and control the high-voltage battery model according to the battery working parameters.

[0011] Preferably, in some schemes, the virtual vehicle-based engine emission digital design system further comprises an automatic calibration module, and pre-calibrated engine working condition standard operating parameters are stored in the automatic calibration module.

[0012] The engine working condition model regularly calls the engine working condition standard operating parameters to calibrate the engine.

[0013] Preferably, in some schemes, the virtual vehicle-based engine emission digital design system further comprises:

[0014] An environment control model is used to adjust a temperature of an environment where the test bench is located, so as to match an operating environment temperature of the target cycle working condition.

[0015] Preferably, in some schemes, the virtual whole vehicle-based engine emission digital design system, the cycle working condition set in the cycle working condition model includes a WLTC working condition cycle, an RDE working condition cycle and an SRC working condition cycle; wherein: the WLTC working condition cycle is a global unified light vehicle test cycle; the RDE working condition cycle is a working condition cycle used in actual road emission test; and the SRC working condition cycle is a working condition cycle used in standard road emission test.

[0016] Preferably, in some schemes, the virtual whole vehicle-based engine emission digital design system, the emission analysis module includes a hydrocarbon sampling channel, a carbon monoxide sampling channel, a nitrogen oxide sampling channel, a carbon dioxide sampling channel, a methane sampling channel and a particulate matter sampling channel.

[0017] The hydrocarbon sampling channel is connected with a hydrocarbon analysis unit;

[0018] The carbon monoxide sampling channel is connected with a carbon monoxide analysis unit;

[0019] The nitrogen oxide sampling channel is connected with a nitrogen oxide analysis unit;

[0020] The carbon dioxide sampling channel is connected with a carbon dioxide analysis unit;

[0021] The methane sampling channel is connected with a methane analysis unit;

[0022] The particulate matter sampling channel is connected with a particulate matter analysis unit.

[0023] Preferably, in some schemes, the virtual whole vehicle-based engine emission digital design system, the main control model sends a prompt signal that the current engine emission development and design is completed when the current engine emission is up to standard, otherwise sends a prompt signal that the current engine emission is not up to standard and the model parameters related to engine control need to be adjusted.

[0024] In a second aspect, the technical scheme of the present application provides a virtual whole vehicle-based engine emission digital design method, comprising:

[0025] Step one: the main control model loads a target cycle working condition from the cycle working condition model;

[0026] Step two: based on the whole vehicle fuel consumption optimization and energy balance criterion, the optimal target engine working condition corresponding to the target cycle working condition is simulated, and the engine is controlled to work at the target engine working condition through the engine working condition model;

[0027] Step three: based on the whole vehicle parameter input, including the whole vehicle mass, the road resistance coefficient, the windward area and the tire radius, the road resistance curve is obtained, and the road resistance model is loaded to the dynamometer.

[0028] Step four: based on the engine operating condition heat dissipation characteristics, the target engine cooling medium temperature rise curve in the target cycle operating condition and the engine compartment target temperature are simulated, and the temperature control loop is controlled by the engine compartment temperature control model to realize temperature control;

[0029] Step five: a driving control model is used to simulate the vehicle driving state;

[0030] Step six: running the target cycle operating condition, the emission analysis module receives the engine emissions and analyzes whether it meets the standard.

[0031] Preferably, in some schemes, the engine emission digital design method based on a virtual whole vehicle,

[0032] In step two, the battery SOC curve corresponding to the target cycle operating condition is also simulated, and the output power of the high-voltage battery is matched with the operation of the engine according to the battery SOC curve through the high-voltage battery model

[0033] The above technical solutions provided by the present application have the following technical effects compared with the prior art:

[0034] The engine emission digital design system and method based on a virtual whole vehicle provided by the present application do not need a physical whole vehicle, an engine, a temperature control loop, a dynamometer and an emission analysis module are set on a bench system, a plurality of cycle operating conditions are pre-stored in a cycle operating condition model in a control subsystem, and a target cycle operating condition is called by a master control model according to design requirements; a driving control model is used to simulate the vehicle driving state; a road resistance model is based on the input of whole vehicle parameters, including the whole vehicle mass, the road resistance coefficient, the windward area and the tire radius, to obtain a road resistance curve; an engine compartment temperature control model is based on the engine operating condition heat dissipation characteristics, the target engine cooling medium temperature rise curve in the target cycle operating condition and the engine compartment target temperature are simulated, and the temperature control loop is controlled by the engine compartment temperature control model to realize temperature control; based on the best whole vehicle fuel consumption and the energy balance criterion, the optimal target engine operating condition corresponding to the target cycle operating condition is simulated, and the engine is controlled to work in the target engine operating condition through an engine operating condition model; an emission analysis module receives the engine emissions and analyzes the emission composition, and a master control model receives the emission composition to judge whether the current engine emission meets the standard. The present application scheme can realize the engine emission design and development without a physical whole vehicle, and can realize the decoupling of the whole vehicle and the decoupling of the driving unit. The whole vehicle emission development is pre-processed, which can greatly shorten the whole vehicle development cycle, improve the development efficiency and save the development cost. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 The structure diagram of the engine emission digital design system based on a virtual whole vehicle according to an embodiment of the present application is shown;

[0036] Figure 2 A structural schematic diagram of an engine emission digital design system based on a virtual whole vehicle according to another embodiment of the present application is shown in the figure;

[0037] Figure 3 A flow chart of an engine emission digital design method based on a virtual whole vehicle according to an embodiment of the present application is shown in the figure;

[0038] Figure 4 A flow chart of an engine emission digital design method based on a virtual whole vehicle according to an embodiment of the present application is shown in the figure.

[0039] The specific embodiments of the present application are further illustrated in the following with reference to the accompanying drawings.

[0040] It is easy to understand that, according to the technical solution of the present application, a person skilled in the art can replace various structural modes and implementation modes without changing the essential spirit of the present application. Therefore, the following specific embodiments and accompanying drawings are only exemplary illustrations of the technical solution of the present application, and should not be regarded as the whole or as a limitation or restriction on the technical solution of the application.

[0041] The present embodiment provides an engine emission digital design system based on a virtual whole vehicle, which comprises a test bench subsystem and a control subsystem, as shown in the figure. Figure 1 The test bench subsystem comprises a test bench and an engine, a temperature control loop, a dynamometer and an emission analysis module arranged on the test bench; the dynamometer receives the torque output by the engine, and the emission analysis module receives the emissions of the engine; the control subsystem comprises a master control model, a cycle condition model, a driving control model, a road resistance model, an engine cabin temperature control model and an engine condition model; the cycle condition model pre-stores a plurality of cycle conditions, and the master control model retrieves a target cycle condition according to design requirements; the driving control model simulates the driving state of the vehicle; the road resistance model obtains a road resistance curve based on the input of whole vehicle parameters, including the mass of the whole vehicle, the road resistance coefficient, the windward area and the tire radius; the engine cabin temperature control model simulates the target temperature rise curve of the engine cooling medium and the target temperature of the engine cabin in the target cycle condition based on the heat dissipation characteristics of the engine condition, and controls the temperature control loop to realize temperature control; the optimal target engine condition corresponding to the target cycle condition is simulated based on the whole vehicle fuel consumption optimization and energy balance criteria, and the engine condition model is used to control the engine to work in the target engine condition; the emission analysis module receives the emissions of the engine and analyzes the composition of the emissions, and the master control model receives the composition of the emissions to determine whether the current engine emissions meet the requirements.

[0042] The temperature control loop built in the system is a three-stage cooling system, and engine coolant, engine oil, and engine intake target temperature models are built to achieve simulation control under different ambient temperatures and to achieve the goal of aligning the engine operating temperature boundary with the actual vehicle environment.

[0043] Preferably, the cycle working condition set in the cycle working condition model includes a WLTC working condition cycle, an RDE working condition cycle, and an SRC working condition cycle; the WLTC working condition cycle is a global uniform light vehicle test cycle; the RDE working condition cycle is a working condition cycle used in actual road emission testing; and the SRC working condition cycle is a working condition cycle used in standard road emission testing. That is, the system builds multiple cycle working condition models including WLTC, RDE, and SRC, and uses the main control model to send the selected target cycle working condition to the driving control model. The driving control model can accurately control the throttle signal based on the relevant driving information given by the main control model, such as the real-time target vehicle speed, to meet the actual vehicle speed control accuracy requirements and ensure the effectiveness of the engine emission results. After obtaining the model data in the vehicle, the engine working condition model can determine the engine operating condition to achieve virtual vehicle emission development.

[0044] It can be understood that the technical solution in the present application is to use a virtual vehicle to replace a physical vehicle to complete the development and design of the engine emission. In specific implementation, in addition to the necessary physical structures such as the engine, the dynamometer, and the temperature control loop, the models that can be connected to the engine through communication signals can be implemented through digital models, but these digital models have the same functions as the actual devices. For example, the engine working condition model can communicate data with the engine, and even in a physical vehicle, the engine is operated under the control of a controller with the same function as the engine working condition model. In the present application, the engine working condition model is used to replace the controller, and the corresponding data is analyzed according to the logic of the controller to obtain the control parameters related to the engine working condition and sent to the engine. Other models such as the driving control model and the road resistance model are similar, that is, a complete physical vehicle does not need to be designed, but part of the virtual model is used to replace the physical device in the physical vehicle, but the virtual model can perform the related analysis and functions of the physical device, and the information related to the engine can be directly sent to the corresponding model or device through communication.

[0045] The above scheme of the embodiment does not need a physical whole vehicle, and sets an engine, a temperature control loop, a dynamometer and an emission analysis module on a test bench subsystem, pre-stores a plurality of cycle working conditions in a cycle working condition model in a control subsystem, and calls a target cycle working condition according to a design requirement by a main control model; a driving control model simulates a vehicle driving state; a road resistance model obtains a road resistance curve based on whole vehicle parameter input, including whole vehicle mass, road resistance coefficient, windward area and tire radius; an engine compartment temperature control model simulates an engine cooling medium target temperature rise curve and an engine compartment target temperature in a target cycle working condition based on engine working condition heat dissipation characteristics, and controls the temperature control loop to realize temperature control; the optimal target engine working condition corresponding to the target cycle working condition is simulated based on whole vehicle fuel consumption optimization and energy balance criteria, and the engine working condition model is used to control the engine to work in the target engine working condition; the emission analysis module receives and analyzes emission components of the engine, and the main control model receives the emission components to judge whether the current engine emission meets the standard. The scheme can realize engine emission design and development without a physical whole vehicle, and realizes decoupling of the whole vehicle and decoupling of the driving unit. The whole vehicle emission development is pre-processed, which can greatly shorten the whole vehicle development cycle, improve the development efficiency and save the development cost.

[0046] Preferably, as shown in Figure 2 The engine emission digital design system based on a virtual whole vehicle further includes a gearbox arranged on the test bench, and the gearbox is arranged between the engine and the dynamometer. The gearbox can be a hybrid gearbox or an automatic gearbox. The test bench subsystem further includes a high-voltage battery model arranged on the test bench, and a power output end of the high-voltage battery model is connected with the gearbox. The driving control model in the control subsystem is further used to calculate battery working parameters of the high-voltage battery model and control the high-voltage battery model according to the battery working parameters. In a specific implementation, a high-voltage battery simulator is used to obtain different SOC states of a power battery, and a hybrid system energy distribution strategy is combined to convert a whole vehicle speed condition into an engine running condition of a target development vehicle. The high-voltage battery model operates according to the adapted SOC state. The scheme is used to simulate an engine running mode of a hybrid vehicle, so as to obtain an engine emission condition.

[0047] In some schemes, the control subsystem further includes an automatic calibration module, and pre-calibrated engine working condition standard operating parameters are stored in the automatic calibration module. The engine working condition model periodically calls the engine working condition standard operating parameters to calibrate the engine. Through the scheme, the running state of the engine can be calibrated within a certain time period, and errors caused by environmental factors and the like can be eliminated.

[0048] Further, the above scheme further comprises an environment control model for adjusting the temperature of the environment where the test bench is located to match the operating environment temperature of the target cycle working condition. Generally, the actual environment temperature where the vehicle is located is: -30℃ to 40℃, therefore, the environment control model can be used to control the temperature of the environment where the test bench is located within the above range and adjust to different environment temperatures to simulate the actual driving environment of the vehicle.

[0049] In the above scheme, the emission analysis module comprises a hydrocarbon sampling channel, a carbon monoxide sampling channel, a nitrogen oxide sampling channel, a carbon dioxide sampling channel, a methane sampling channel and a particulate matter sampling channel; the hydrocarbon sampling channel is connected with a hydrocarbon analysis unit; the carbon monoxide sampling channel is connected with a carbon monoxide analysis unit; the nitrogen oxide sampling channel is connected with a nitrogen oxide analysis unit; the carbon dioxide sampling channel is connected with a carbon dioxide analysis unit; the methane sampling channel is connected with a methane analysis unit; and the particulate matter sampling channel is connected with a particulate matter analysis unit. Through the scheme, the system is configured with sampling channels of THC, CO, NOx, CO2, O2, CH4 and PN which meet the emission regulation requirements, and high-precision exhaust flow measurement data is combined to analyze and calculate the engine emission content in real time to obtain the regulation emission result.

[0050] In the above scheme, the main control model sends a prompt signal indicating that the current engine emission development and design is completed when the current engine emission meets the standard, otherwise sends a prompt signal indicating that the model parameters related to engine control need to be adjusted when the current engine emission does not meet the standard. That is, if the engine emission does not meet the standard, it means that there are some inappropriate control parameters in the above models, which need to be adjusted and then the emission design is performed again until the engine emission meets the standard.

[0051] As shown in Figure 3 The application also provides an engine emission digital design method based on a virtual whole vehicle, comprising:

[0052] Step one: the main control model loads the target cycle working condition from the cycle working condition model.

[0053] For example, WLTC, RDE, SRC cycle working condition.

[0054] Step two: based on the whole vehicle fuel consumption optimization and energy balance criterion, the optimal target engine working condition corresponding to the target cycle working condition is simulated, and the engine working condition model is used to control the engine to work at the target engine working condition. If it is a hybrid vehicle, this step further comprises simulating the battery SOC curve corresponding to the target cycle working condition, and the high-voltage battery model is used to output power according to the battery SOC curve and the operation of the engine.

[0055] Step three: based on the vehicle parameter input, including vehicle mass, road resistance coefficient, wind area, tire radius, get the road resistance curve, through the road resistance model loaded to the dynamometer.

[0056] Step four: based on the engine operating heat dissipation characteristics, the target cycle operating condition is simulated to obtain the engine cooling medium target temperature rise curve, the engine compartment target temperature, and the temperature control loop is realized through the engine compartment temperature control model to control the temperature.

[0057] Step five: driving control model, simulating the vehicle driving state.

[0058] Step six: run the target cycle operating condition, the emission analysis module receives the engine emissions and analyzes whether it meets the standard.

[0059] In the above scheme, after inputting the data required for operation to different models, each model can calculate the target result by itself, for example, after receiving the vehicle mass, road resistance coefficient, wind area and tire radius, the road resistance model can calculate the road resistance coefficient.

[0060] Figure 4 The above scheme gives a specific process for engine development and design using the above scheme for the typical I-type test WLTC operating condition in GB6 emission regulations. It can be understood that there is no absolute sequence for some steps. The above scheme realizes real-time simulation of the whole vehicle thermal environment, simulation of the SOC state of the power battery, the road resistance of the whole vehicle, the driving condition of the whole vehicle, real-time conversion from the whole vehicle operating condition to the engine operating condition through simulation of hybrid electric drive, automatic transmission drive, combined with integrated emission collection and analysis system, and finally realizes the emission development of hybrid drive system, pure electric drive system related vehicle models under the condition of no physical whole vehicle, WLTC, RDE, SRC and other driving cycles, realizes the decoupling of emission development and whole vehicle, and the decoupling of driving unit.

[0061] According to the needs, the above technical solutions can be combined to achieve the best technical effect.

[0062] The above is only the principle and preferred embodiment of the present application. It should be noted that for those skilled in the art, on the basis of the principles of the present application, a number of other variations can also be made, which should be considered as the protection scope of the present application.

Claims

1. A virtual vehicle-based engine emission digital design system, characterized in that, The system comprises a test bench subsystem and a control subsystem, wherein: The test bench subsystem comprises a test bench and an engine, a temperature control loop, a dynamometer and an emission analysis module arranged on the test bench; the dynamometer receives the torque output by the engine, and the emission analysis module receives the emissions of the engine; The control subsystem comprises a master control model, a cycle working condition model, a driving control model, a road resistance model, an engine cabin temperature control model and an engine working condition model; the cycle working condition model pre-stores a plurality of cycle working conditions, and the master control model calls a target cycle working condition according to design requirements; the driving control model simulates the driving state of the vehicle; the road resistance model obtains a road resistance curve based on the input of vehicle parameters, including vehicle mass, road resistance coefficient, windward area and tire radius; the engine cabin temperature control model simulates the target temperature rise curve of the engine cooling medium and the target temperature of the engine cabin in the target cycle working condition based on the heat dissipation characteristics of the engine working condition, and controls the temperature control loop to achieve temperature control; the optimal target engine working condition corresponding to the target cycle working condition is simulated based on the optimal vehicle fuel consumption and energy balance criteria, and the engine working condition model controls the engine to work in the target engine working condition; the emission analysis module receives the emissions of the engine and analyzes the composition of the emissions, and the master control model receives the composition of the emissions to determine whether the current engine emissions meet the standards.

2. The virtual vehicle-based engine emission digital design system according to claim 1, wherein: The test bench subsystem further comprises a gearbox arranged on the test bench, and the gearbox is arranged between the engine and the dynamometer.

3. The virtual vehicle-based engine emission digital design system according to claim 2, wherein: The test bench subsystem further comprises a high-voltage battery model arranged on the test bench, and the power output end of the high-voltage battery model is connected to the gearbox; The driving control model in the control subsystem is further used to calculate the battery working parameters of the high-voltage battery model and control the high-voltage battery model according to the battery working parameters.

4. The virtual vehicle-based engine emission digital design system according to claim 1, wherein: The control subsystem further comprises an automatic calibration module, and the memory of the automatic calibration module stores pre-calibrated engine working condition standard operating parameters; The engine working condition model periodically calls the engine working condition standard operating parameters to calibrate the engine.

5. The virtual vehicle-based engine emission digital design system of claim 1, wherein, Further comprising: An environment control model for adjusting the temperature of the environment in which the test bench is located to match the operating environment temperature of the target cycle working condition.

6. The virtual vehicle-based engine emission digital design system according to claim 1, wherein: The cycle working condition set in the cycle working condition model includes a WLTC working condition cycle, an RDE working condition cycle and an SRC working condition cycle; wherein, the WLTC working condition cycle is a global uniform light vehicle test cycle; the RDE working condition cycle is a working condition cycle used in actual road emission test; and the SRC working condition cycle is a working condition cycle used in standard road emission test.

7. The virtual vehicle-based engine emission digital design system according to claim 6, characterized in that: The emission analysis module comprises a hydrocarbon sampling channel, a carbon monoxide sampling channel, a nitrogen oxide sampling channel, a carbon dioxide sampling channel, a methane sampling channel and a particulate matter sampling channel; The hydrocarbon sampling channel is connected with a hydrocarbon analysis unit; The carbon monoxide sampling channel is connected with a carbon monoxide analysis unit; The nitrogen oxide sampling channel is connected with a nitrogen oxide analysis unit; The carbon dioxide sampling channel is connected with a carbon dioxide analysis unit; The methane sampling channel is connected with a methane analysis unit; The particulate matter sampling channel is connected with a particulate matter analysis unit.

8. The virtual vehicle-based engine emission digital design system according to any one of claims 1-7, characterized in that: The master control model sends a prompt signal indicating that the current engine emission development and design is completed when the current engine emission is up to standard, or sends a prompt signal indicating that the model parameters related to engine control need to be adjusted when the current engine emission is not up to standard.

9. A virtual whole vehicle-based engine emission digital design method, characterized in that, Comprising: Step one: the master control model loads a target cycle working condition from the cycle working condition model; Step two: based on the best vehicle fuel consumption and energy balance criteria, the optimal target engine working condition corresponding to the target cycle working condition is simulated, and the engine is controlled to work at the target engine working condition through the engine working condition model; Step three: based on the vehicle parameter input, including vehicle mass, road resistance coefficient, wind area and tire radius, the road resistance curve is obtained, and the road resistance model is loaded to the dynamometer; Step four: based on the engine working condition heat dissipation characteristics, the target temperature rise curve of the engine cooling medium in the target cycle working condition and the target temperature of the engine compartment are simulated, and the temperature control loop is controlled through the engine compartment temperature control model to realize temperature control; Step five: the driving control model simulates the vehicle driving state; Step six: the target cycle working condition is run, and the emission analysis module receives the engine emissions and analyzes whether they are up to standard.

10. The virtual vehicle-based engine emission digital design method according to claim 9, characterized in that: In step two, the battery SOC curve corresponding to the target cycle working condition is also simulated, and the high-voltage battery model outputs power according to the battery SOC curve in cooperation with the operation of the engine.

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