Engine air-fuel ratio control method for dual-motor hybrid power system

Abstract

The invention provides a dual-motor hybrid power system engine air-fuel ratio control method, device and equipment and a storage medium, and relates to the technical field of hybrid electric vehicles. The operation states comprise that the engine operates only under the power generation working condition, the engine and the driving motor operate at the same time and the engine operates only under the direct-drive working condition, when the engine operates only under the power generation working condition, air-fuel ratio control is conducted on the engine according to the excess air coefficient value in the first excess air coefficient graph, and when the engine and the driving motor operate at the same time, air-fuel ratio control is conducted on the engine. And when the engine operates under the direct-drive working condition, the air-fuel ratio of the engine is controlled according to the excess air coefficient value in the second excess air coefficient graph, and when the engine only operates under the direct-drive working condition, the air-fuel ratio of the engine is controlled according to the excess air coefficient value in the third excess air coefficient graph. In this way, the engine adopts different air-fuel ratio control in different operation modes, so that the fuel consumption of the hybrid electric vehicle can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of hybrid vehicles, and particularly to a method, device, equipment and storage medium for controlling the air-fuel ratio of an engine in a dual-motor hybrid system. Background Art

[0002] A hybrid vehicle refers to a vehicle whose drive system is composed of two or more single drive systems that can operate simultaneously. Its engine consists of an internal combustion engine and an electric motor. The internal combustion engine is used to provide power under low load, and the electric motor is used to provide power under high load. They can work separately or simultaneously. In addition, the engine of a hybrid vehicle is also equipped with a generator, which is used to convert the energy of the internal combustion engine into electrical energy when the vehicle accelerates, so as to store the electrical energy and output the electrical energy to the electric motor when needed.

[0003] When the engine of the vehicle is working, a certain air-fuel ratio needs to be satisfied, that is, there is an appropriate ratio between the fuel and the inhaled air to form a combustible mixture. Hybrid vehicles have different operating modes. If the same air-fuel ratio is adopted in different operating modes, it will lead to higher fuel consumption of the hybrid vehicle. Summary of the Invention

[0004] In view of the above problems, the present application provides a method and device for controlling the air-fuel ratio of an engine in a dual-motor hybrid system, including the following:

[0005] In a first aspect, the present application provides a method for controlling the air-fuel ratio of an engine in a dual-motor hybrid system, including:

[0006] Obtaining the operating state of the engine, where the operating state includes the engine operating only in the power generation mode, the engine operating simultaneously with the drive motor, and the engine operating only in the direct drive mode;

[0007] When the engine is operating only in the power generation mode, controlling the air-fuel ratio of the engine according to the value of the excess air coefficient in the first excess air coefficient map;

[0008] When the engine is operating simultaneously with the drive motor, controlling the air-fuel ratio of the engine according to the value of the excess air coefficient in the second excess air coefficient map;

[0009] When the engine is operating only in the direct drive mode, controlling the air-fuel ratio of the engine according to the value of the excess air coefficient in the third excess air coefficient map;

[0010] The values of the excess air coefficient in the first excess air coefficient map, the values of the excess air coefficient in the second excess air coefficient map, and the values of the excess air coefficient in the third excess air coefficient map are different. The abscissa of the excess air coefficient map is the engine speed, and the ordinate is the engine load.

[0011] Optionally, when the engine operates only in the power generation mode, controlling the air-fuel ratio of the engine according to the air-fuel ratio coefficient value in the first air-fuel ratio coefficient map includes:

[0012] Controlling the range of the air-fuel ratio coefficient value corresponding to the air-fuel ratio of the engine to be 1.1 to 2;

[0013] When the vehicle is in the intermediate economic fuel consumption region, the intermediate fuel consumption region is the fuel consumption region after multiplying the minimum fuel consumption point by 1.2, and the range of the air-fuel ratio coefficient value is 1.5 to 2; in other regions, the range of the air-fuel ratio coefficient is 1.1 to 1.5.

[0014] Optionally, when the engine and the drive motor operate simultaneously, controlling the air-fuel ratio of the engine according to the air-fuel ratio coefficient value in the second air-fuel ratio coefficient map includes:

[0015] Controlling the air-fuel ratio coefficient value corresponding to the air-fuel ratio of the engine to be 1.

[0016] Optionally, when the engine operates only in the direct drive mode, controlling the air-fuel ratio of the engine according to the air-fuel ratio coefficient value in the third air-fuel ratio coefficient map includes:

[0017] Controlling the range of the air-fuel ratio coefficient value corresponding to the air-fuel ratio of the engine to be 0.8 to 0.98 or taking the value of 1.

[0018] Optionally, controlling the air-fuel ratio coefficient value corresponding to the air-fuel ratio of the engine to be any value between 0.8 and 0.98 or 1 includes:

[0019] When the load of the engine is between 90% and 100%, controlling the air-fuel ratio coefficient value corresponding to the air-fuel ratio of the engine to be any value between 0.8 and 0.98, and in other cases, controlling the air-fuel ratio coefficient value corresponding to the air-fuel ratio of the engine to be 1.

[0020] In a second aspect, the present application provides a device for controlling the air-fuel ratio of an engine in a dual-motor hybrid power system, including:

[0021] An acquisition unit for acquiring the operating state of the engine, where the operating state includes that the engine operates only in the power generation mode, the engine and the drive motor operate simultaneously, and the engine operates only in the direct drive mode;

[0022] A control unit for, when the engine operates only in the power generation mode, controlling the air-fuel ratio of the engine according to the air-fuel ratio coefficient value in the first air-fuel ratio coefficient map;

[0023] When the engine and the drive motor operate simultaneously, the air-fuel ratio of the engine is controlled according to the excess air coefficient value in the second excess air coefficient map;

[0024] When the engine operates only in the direct drive mode, the air-fuel ratio of the engine is controlled according to the excess air coefficient value in the third excess air coefficient map;

[0025] The excess air coefficient values in the first excess air coefficient map, the second excess air coefficient map, and the third excess air coefficient map are different. The abscissa of the excess air coefficient map is the engine speed, and the ordinate is the engine load.

[0026] Optionally, when the engine operates only in the power generation mode, the control unit is specifically configured to:

[0027] Control the range of the excess air coefficient value corresponding to the air-fuel ratio of the engine to be 1.1 to 2;

[0028] When the vehicle is in the intermediate economic fuel consumption area, the intermediate fuel consumption area is the fuel consumption area after multiplying the minimum fuel consumption point by 1.2, and the range of the excess air coefficient value is 1.5 to 2; in other areas, the range of the excess air coefficient is 1.1 to 1.5.

[0029] Optionally, when the engine and the drive motor operate simultaneously, the control unit is specifically configured to:

[0030] Control the excess air coefficient value corresponding to the air-fuel ratio of the engine to be 1.

[0031] Optionally, when the engine operates only in the direct drive mode, the control unit is specifically configured to:

[0032] Control the range of the excess air coefficient value corresponding to the air-fuel ratio of the engine to be 0.8 to 0.98 or take the value of 1.

[0033] Optionally, the excess air coefficient value corresponding to the air-fuel ratio of the engine being any value between 0.8 and 0.98 or 1 includes:

[0034] When the load of the engine is between 90% and 100%, control the excess air coefficient value corresponding to the air-fuel ratio of the engine to be any value between 0.8 and 0.98. Otherwise, control the excess air coefficient value corresponding to the air-fuel ratio of the engine to be 1.

[0035] In a third aspect, the present application provides a device, which includes a memory and a processor. The memory is used to store instructions or codes, and the processor is used to execute the instructions or codes so that the device executes the engine air-fuel ratio control method for the dual-motor hybrid power system according to any one of the foregoing first aspects.

[0036] In a fourth aspect, the present application provides a computer-readable storage medium in which codes are stored. When the codes are run, the device running the codes implements the engine air-fuel ratio control method for the dual-motor hybrid power system according to any one of the foregoing first aspects.

[0037] The present application provides an engine air-fuel ratio control method for a dual-motor hybrid power system. When executing the method, the operating state of the engine is obtained. The operating state includes the engine operating only in the power generation mode, the engine and the drive motor operating simultaneously, and the engine operating only in the direct drive mode. When the engine operates only in the power generation mode, the air-fuel ratio of the engine is controlled according to the air-fuel ratio coefficient value in the first air-fuel ratio coefficient map. When the engine and the drive motor operate simultaneously, the air-fuel ratio of the engine is controlled according to the air-fuel ratio coefficient value in the second air-fuel ratio coefficient map. When the engine operates only in the direct drive mode, the air-fuel ratio of the engine is controlled according to the air-fuel ratio coefficient value in the third air-fuel ratio coefficient map. The air-fuel ratio coefficient values in the first air-fuel ratio coefficient map, the second air-fuel ratio coefficient map, and the third air-fuel ratio coefficient map are different. The abscissa of the air-fuel ratio coefficient map is the engine speed, and the ordinate is the engine load.

[0038] In this way, by adopting different air-fuel ratio controls for the engine in different operating modes, the fuel consumption of the hybrid vehicle can be reduced. Description of the Drawings

[0039] To more clearly illustrate the technical solutions in the embodiments or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0040] Figure 1 It is a flowchart of an engine air-fuel ratio control method for a dual-motor hybrid power system provided by an embodiment of the present application;

[0041] Figure 2 It is a schematic diagram of a vehicle structure provided by an embodiment of the present application;

[0042] Figure 3Schematic structural diagram of an air-fuel ratio control device for an engine of a dual-motor hybrid power system provided by an embodiment of the present application. Detailed implementation manners

[0043] As described in the background art of the present application, when the engine of a vehicle is operating, a certain air-fuel ratio needs to be satisfied, that is, an appropriate ratio between the fuel and the inhaled air, in order to form a combustible mixture. A hybrid vehicle has different operating modes. If the same air-fuel ratio is adopted in different operating modes, it will result in a relatively high fuel consumption of the hybrid vehicle.

[0044] To solve the above technical problems, an embodiment of the present application provides an air-fuel ratio control method for an engine of a dual-motor hybrid power system, and the method includes:

[0045] Obtain the operating state of the engine, where the operating state includes the engine operating only in the power generation mode, the engine and the drive motor operating simultaneously, and the engine operating only in the direct drive mode. When the engine is operating only in the power generation mode, control the air-fuel ratio of the engine according to the value of the excess air coefficient in the first excess air coefficient map. When the engine and the drive motor are operating simultaneously, control the air-fuel ratio of the engine according to the value of the excess air coefficient in the second excess air coefficient map. When the engine is operating only in the direct drive mode, control the air-fuel ratio of the engine according to the value of the excess air coefficient in the third excess air coefficient map. The values of the excess air coefficient in the first excess air coefficient map, the values of the excess air coefficient in the second excess air coefficient map, and the values of the excess air coefficient in the third excess air coefficient map are different. The abscissa of the excess air coefficient map is the engine speed, and the ordinate is the engine load. In this way, by adopting different air-fuel ratio controls for the engine in different operating modes, the fuel consumption of the hybrid vehicle can be reduced.

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0047] Figure 1 Flowchart of an air-fuel ratio control method for an engine of a dual-motor hybrid power system provided by an embodiment of the present application. Combining Figure 1 As shown, the air-fuel ratio control method for an engine of a dual-motor hybrid power system provided by an embodiment of the present application may include:

[0048] S101. Obtain the operating state of the engine, where the operating state includes the engine operating only in the power generation mode, the engine and the drive motor operating simultaneously, and the engine operating only in the direct drive mode.

[0049] The method in this application is applicable to hybrid vehicles. Hybrid vehicles include multiple operating modes, and the operating state of the engine is different in different operating modes. In order to reduce the fuel consumption of hybrid vehicles, it is necessary to control the engine to adopt different air-fuel ratios in different operating modes.

[0050] The air-fuel ratio is the ratio between air and fuel. It means that when the engine is working, the fuel must be in an appropriate ratio with the inhaled air to form a combustible mixture.

[0051] S102. When the engine is operating only in the power generation mode, control the air-fuel ratio of the engine according to the excess air coefficient value in the first excess air coefficient map.

[0052] The excess air coefficient map refers to the Lambda map of the engine. The excess air coefficient is an important parameter reflecting the fuel-air mixture ratio, and is usually represented by the symbol "λ". The abscissa of the excess air coefficient map is the engine speed, and the ordinate is the engine load. The engine load refers to the magnitude of the load borne by the engine. When the load borne by the engine is large, the intake air volume and fuel injection volume need to be increased accordingly, that is, enrichment control is required. In this application, the engine has three different operating states, and the corresponding air coefficient maps are different in different operating states, and the air coefficient values in different air coefficient maps are also different.

[0053] When the engine of a hybrid vehicle is operating only in the power generation mode, the Lambda sensor on the vehicle is usually called an oxygen sensor or an O2 sensor. Control the air-fuel ratio of the engine according to the excess air coefficient value in the first excess air coefficient map. Specifically, the range of the excess air coefficient value corresponding to the air-fuel ratio of the controlled engine is 1.1 to 2. When the vehicle is in the intermediate economic fuel consumption area, the intermediate fuel consumption area is the fuel consumption area after multiplying the minimum fuel consumption point by 1.2, and the range of the excess air coefficient value is 1.5 to 2. In other areas, the range of the excess air coefficient is 1.1 to 1.5.

[0054] In the first excess air coefficient map, the engine operates in a lean burn mode at any load value. Lean burn means that in order to reduce fuel consumption and pollution, a lean mixture with a large air-fuel ratio should be used as much as possible, and a rich mixture is only provided when necessary in special cases. Therefore, in the first excess air coefficient map, the range of the Lambda value is 1.1 to 2.

[0055] S103. When the engine and the drive motor operate simultaneously, the air-fuel ratio of the engine is controlled according to the value of the excess air ratio in the second excess air ratio map.

[0056] In the second excess air ratio map, at any load value, the air-fuel ratio of the engine is stoichiometric combustion, that is, the air and fuel are 1:1, that is, lambda = 1.

[0057] Therefore, when the engine and the drive motor operate simultaneously, the air-fuel ratio of the engine is controlled according to the value of the excess air ratio in the second excess air ratio map. Specifically, the value of the excess air ratio corresponding to the air-fuel ratio of the engine to be controlled is 1.

[0058] S104. When the engine operates only in the direct drive mode, the air-fuel ratio of the engine is controlled according to the value of the excess air ratio in the third excess air ratio map.

[0059] When the engine operates only in the direct drive mode, the air-fuel ratio of the engine is controlled according to the value of the excess air ratio in the third excess air ratio map. The value range of the excess air ratio corresponding to the air-fuel ratio of the engine to be controlled is 0.8 to 0.98 or the value is 1.

[0060] In the third excess air ratio map, the excess air ratio has two value ranges. Near the external characteristic, that is, when the load is 90% to 100%, it is necessary to control the engine to adopt a rich combustion mode, that is, to increase the fuel intake. Specifically, when the load of the engine is 90% to 100%, the value of the excess air ratio corresponding to the air-fuel ratio of the engine is any value between 0.8 and 0.98. Otherwise, the value of the excess air ratio corresponding to the air-fuel ratio of the engine is 1.

[0061] The above is a method for controlling the air-fuel ratio of an engine in a dual-motor hybrid power system provided by an embodiment of the present application. The above control process will be introduced below in combination with the structure of a specific hybrid vehicle. Figure 2 It is a schematic diagram of a vehicle structure provided by an embodiment of the present application. Figure 2 It includes: engine 1, engine output shaft 2, first gear 3, second gear 4, generator 5, clutch 6, third gear 7, fourth gear 8, fifth gear 9, drive motor 10, sixth gear 11, differential 12.

[0062] One end of the engine output shaft 2 is arranged inside the engine 1. The other end of the engine output shaft 2 is connected to one end of the clutch 6. The first gear 3 is connected to the middle part of the engine output shaft 2. The second gear 4 meshes with the first gear 3. The connecting shaft of the generator 5 is connected to the second gear 4. The connecting shaft of the third gear 7 is connected to the other end of the clutch 6. The fourth gear 8 meshes with the third gear 7 and the fifth gear 9 respectively. The connecting shaft of the drive motor 10 is connected to the fifth gear 9. The fourth gear 8 and the sixth gear 11 are connected by a connecting shaft. The differential 12 meshes with the sixth gear 11.

[0063] In one implementation of the embodiment of the present application, the generator 5 can also be directly connected to the engine output shaft 2, that is, it becomes an ISG generator.

[0064] During the implementation process of the engine air-fuel ratio control method for the dual-motor hybrid power system provided in the embodiment of the present application, when the engine 1 is only operating in the power generation mode, the engine 1 is only used to drive the generator 5 to work alone; at this time, the clutch 6 is disengaged, and the whole vehicle is in the state of being driven solely by the drive motor 10. At this time, the Lambda of the engine 1 can be controlled according to the first Lambdamap. When the engine 1 is operating in the optimal fuel consumption area, the operating condition of the engine 1 is relatively stable, and Lambda can be thinned by about 1.7. When the engine 1 has just started and is operating in the small load area, if Lambda is directly thinned to around 1.7, it is likely to cause misfire of the engine 1. Therefore, in the area outside the optimal fuel consumption area, Lambda needs to be appropriately thinned to about 1.1.

[0065] When the engine 1 and the drive motor 10 drive the whole vehicle together, the clutch 6 is closed, the engine 1 and the drive motor 10 work in parallel, and the generator 5 is in a non-operating state. At this time, the Lambda of the engine can be controlled according to the second Lambdamap, and Lambda is controlled at 1 throughout the map. When the engine 1 and the drive motor 10 drive the whole vehicle together, the operating condition of the engine 1 will also change in real time. However, due to the participation of the drive motor 10, the speed and load of the engine 1 will not be too high. Therefore, controlling the Lambda of the engine 1 to be 1 at this time can not only reduce fuel consumption but also avoid misfire of the engine 1 during the working condition switching process.

[0066] When the engine 1 operates only in the direct drive mode, the generator 5 and the drive motor 10 do not work, the clutch 6 is closed, and the whole vehicle is in the state of being driven only by the engine 1. At this time, the Lambda of the engine 1 can be controlled according to the third Lambdamap. The engine 1 operates within the full operating range, and the changes in the speed and load of the engine 1 at different operating points are relatively large. To protect the various components of the engine 1 and reduce the exhaust temperature, when the engine 1 operates near the external characteristic, Lambda needs to be appropriately enriched and controlled at about 0.9. In other medium and small load conditions, Lambda is controlled at 1.

[0067] The above are some specific implementation manners of a method for controlling the air-fuel ratio of an engine in a dual-motor hybrid power system provided by an embodiment of the present application. Based on this, the present application also provides a corresponding device. The device provided by the embodiment of the present application will be introduced from the perspective of functional modularization below.

[0068] Figure 3 It is a schematic structural diagram of a device for controlling the air-fuel ratio of an engine in a dual-motor hybrid power system provided by an embodiment of the present application. Combining Figure 3 As shown, the device 300 for controlling the air-fuel ratio of an engine in a dual-motor hybrid power system provided by an embodiment of the present application includes:

[0069] An acquisition unit 310, configured to acquire the operating state of the engine, where the operating state includes that the engine operates only in the power generation mode, the engine operates simultaneously with the drive motor, and the engine operates only in the direct drive mode;

[0070] A control unit 320, configured to, when the engine operates only in the power generation mode, control the air-fuel ratio of the engine according to the air-fuel ratio value in the first excess air coefficient map;

[0071] When the engine operates simultaneously with the drive motor, control the air-fuel ratio of the engine according to the air-fuel ratio value in the second excess air coefficient map;

[0072] When the engine operates only in the direct drive mode, control the air-fuel ratio of the engine according to the air-fuel ratio value in the third excess air coefficient map;

[0073] The air-fuel ratio values in the first excess air coefficient map, the air-fuel ratio values in the second excess air coefficient map, and the air-fuel ratio values in the third excess air coefficient map are different. The abscissa of the excess air coefficient map is the engine speed, and the ordinate is the engine load.

[0074] In an implementation manner of the embodiment of the present application, the control unit is specifically configured to:

[0075] The range of the excess air coefficient value corresponding to the air-fuel ratio of the engine is controlled to be from 1.1 to 2;

[0076] When the vehicle is in the intermediate economic fuel consumption region, the intermediate fuel consumption region is the fuel consumption region after multiplying the minimum fuel consumption point by 1.2, and the range of the excess air coefficient value is from 1.5 to 2; in other regions, the range of the excess air coefficient is from 1.1 to 1.5.

[0077] In an implementation manner of the embodiment of the present application, when the engine and the drive motor operate simultaneously, the control unit is specifically configured to:

[0078] Control the excess air coefficient value corresponding to the air-fuel ratio of the engine to be 1.

[0079] In an implementation manner of the embodiment of the present application, when the engine operates only in the direct drive condition, the control unit is specifically configured to:

[0080] Control the range of the excess air coefficient value corresponding to the air-fuel ratio of the engine to be from 0.8 to 0.98 or the value is 1.

[0081] In an implementation manner of the embodiment of the present application, the excess air coefficient value corresponding to the air-fuel ratio of the engine being any value between 0.8 and 0.98 or 1 includes:

[0082] When the load of the engine is between 90% and 100%, control the excess air coefficient value corresponding to the air-fuel ratio of the engine to be any value between 0.8 and 0.98, and in other cases, control the excess air coefficient value corresponding to the air-fuel ratio of the engine to be 1.

[0083] The embodiment of the present application also provides a corresponding device and a computer storage medium for implementing the solution provided by the embodiment of the present application.

[0084] Among them, the device includes a memory and a processor. The memory is used to store instructions or codes, and the processor is used to execute the instructions or codes so that the device executes the method described in any embodiment of the present application.

[0085] The computer storage medium stores codes. When the codes are run, the device running the codes implements the method described in any embodiment of the present application.

[0086] As can be seen from the description of the above embodiments, those skilled in the art can clearly understand that all or part of the steps in the above-described embodiment methods can be implemented by means of software plus a general hardware platform. Based on such an understanding, the technical solution of the present application can be embodied in the form of a software product, which can be stored in a storage medium, such as a read-only memory (ROM) / RAM, magnetic disk, optical disk, etc., including several instructions for causing a computer device (which can be a personal computer, a server, or a network communication device such as a router) to execute the methods described in various embodiments or certain parts of the embodiments of the present application.

[0087] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover a non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0088] It should also be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the device and apparatus embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiments. The device and apparatus embodiments described above are only illustrative. The units described as separate components may or may not be physically separated, and the components described as units may or may not be physical units, that is, they may be located in one place, or may be distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0089] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for controlling the air-fuel ratio of an engine in a dual-motor hybrid power system, characterized in that, The method includes: Obtaining the operating state of the engine, where the operating state includes the engine operating only in the power generation mode, the engine and the drive motor operating simultaneously, and the engine operating only in the direct drive mode; When the engine is operating only in the power generation mode, controlling the air-fuel ratio of the engine according to the excess air coefficient value in the first excess air coefficient map; When the engine and the drive motor are operating simultaneously, controlling the air-fuel ratio of the engine according to the excess air coefficient value in the second excess air coefficient map; When the engine is operating only in the direct drive mode, controlling the air-fuel ratio of the engine according to the excess air coefficient value in the third excess air coefficient map; The excess air coefficient values in the first excess air coefficient map, the second excess air coefficient map, and the third excess air coefficient map are different. The abscissa of the excess air coefficient map is the engine speed, and the ordinate is the engine load.

2. The method according to claim 1, characterized in that When the engine is operating only in the power generation mode, controlling the air-fuel ratio of the engine according to the excess air coefficient value in the first excess air coefficient map includes: Controlling the range of the excess air coefficient value corresponding to the air-fuel ratio of the engine to be from 1.1 to 2; When the vehicle is in the intermediate economic fuel consumption area, the intermediate fuel consumption area is the fuel consumption area after multiplying the minimum fuel consumption point by 1.2, and the range of the excess air coefficient value is from 1.5 to 2; in other areas, the range of the excess air coefficient is from 1.1 to 1.

5.

3. The method according to claim 1, characterized in that, When the engine and the drive motor are operating simultaneously, controlling the air-fuel ratio of the engine according to the excess air coefficient value in the second excess air coefficient map includes: Controlling the excess air coefficient value corresponding to the air-fuel ratio of the engine to be 1.

4. The method according to claim 1, wherein When the engine is operating only in the direct drive mode, controlling the air-fuel ratio of the engine according to the excess air coefficient value in the third excess air coefficient map includes: Controlling the range of the excess air coefficient value corresponding to the air-fuel ratio of the engine to be from 0.8 to 0.98 or taking the value of 1.

5. The method according to claim 4, wherein The controlling the excess air coefficient value corresponding to the air-fuel ratio of the engine to be any value between 0.8 and 0.98 or 1 includes: When the load of the engine is between 90% and 100%, controlling the excess air coefficient value corresponding to the air-fuel ratio of the engine to be any value between 0.8 and 0.98; otherwise, controlling the excess air coefficient value corresponding to the air-fuel ratio of the engine to be 1.

6. A device for controlling the air-fuel ratio of an engine in a dual-motor hybrid power system, characterized in that, The device includes: An obtaining unit for obtaining the operating state of the engine, where the operating state includes the engine operating only in the power generation mode, the engine and the drive motor operating simultaneously, and the engine operating only in the direct drive mode; A control unit for, when the engine is operating only in the power generation mode, controlling the air-fuel ratio of the engine according to the excess air coefficient value in the first excess air coefficient map; When the engine and the drive motor are operating simultaneously, controlling the air-fuel ratio of the engine according to the excess air coefficient value in the second excess air coefficient map; When the engine is operating only in the direct drive mode, controlling the air-fuel ratio of the engine according to the excess air coefficient value in the third excess air coefficient map; The excess air coefficient values in the first excess air coefficient map, the excess air coefficient values in the second excess air coefficient map, and the excess air coefficient values in the third excess air coefficient map are different. The abscissa of the excess air coefficient map is the engine speed, and the ordinate is the engine load.

7. The device according to claim 6, characterized in that, When the engine operates only in the power generation mode, the control unit is specifically configured to: control the range of the excess air coefficient value corresponding to the air-fuel ratio of the engine to be 1.1 to 2; When the vehicle is in the intermediate economic fuel consumption area, the intermediate fuel consumption area is the fuel consumption area after multiplying the minimum fuel consumption point by 1.2, and the range of the excess air coefficient value is 1.5 to 2; in other areas, the range of the excess air coefficient is 1.1 to 1.

5.

8. The device according to claim 6, characterized in that, When the engine and the drive motor operate simultaneously, the control unit is specifically configured to: control the excess air coefficient value corresponding to the air-fuel ratio of the engine to be 1.

9. A computing device, characterized in that, The computing device includes: a memory and a processor; The memory is used to store computer programs; The processor is configured to implement the method according to any one of claims 1 to 5 when executing the computer program.

10. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, and when the computer program is executed by the processor, the method according to any one of claims 1 to 5 is implemented.

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