Electrically-driven four-wheel-drive control method, electrically-driven four-wheel-drive architecture system and new energy automobile

Abstract

The invention provides an electrically-driven four-wheel-drive control method, an electrically-driven four-wheel-drive architecture system and a new energy vehicle, relates to the technical field of new energy vehicles, and solves the technical problem that the endurance of a four-wheel-drive electric vehicle is lower than that of a two-wheel-drive electric vehicle. The electrically-driven four-wheel-drive architecture system is of a front-rear double-permanent-magnet four-wheel-drive architecture and comprises a front permanent magnet motor installed on a front axle to form a front drive; the rear permanent magnet motor is provided with a disengagement device and is mounted on the rear shaft to form a rear drive; the front permanent magnet motor and the rear permanent magnet motor are both of a non-platform design structure, and the power and torque of the front permanent magnet motor and the rear permanent magnet motor are different. The four-wheel-drive structure with the front permanent magnet and the rear permanent magnet is adopted, the power and the torque of one motor are remarkably large, and the motor is provided with a disengaging device and is mainly used in a relatively low-speed application scene, namely rear drive; the power torque of the other motor is obviously small, and the other motor is installed on a front axle, namely a front drive, has the advantage of being high in efficiency at high speed and is in a driving or feedback state all the time, so that the endurance mileage of a four-wheel-drive vehicle type is better than that of a two-wheel-drive vehicle type with the same electric quantity.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to an electric drive four-wheel drive control method, an electric drive four-wheel drive architecture system and a new energy vehicle. Background Art

[0002] New energy vehicles include extended-range electric vehicles, pure electric electric vehicles, etc. Both extended-range electric vehicles and pure electric electric vehicles include electric motors, which are usually arranged on the vehicle and connected to the front or rear axle of the vehicle to drive the operation of the new energy vehicle and recover kinetic energy during braking. However, since the power transmission between the electric motor and the wheels is often achieved through intermediate transmission mechanisms such as differentials and drive shafts, and each level of the transmission mechanism will cause partial power loss, the vehicle weight, drag coefficient, frontal area, and rolling resistance coefficient of each model may be different from other models, so each model has a relatively most suitable electric drive assembly, which makes its overall efficiency relatively high.

[0003] Four-wheel drive refers to a configuration in which an electric vehicle has an electric drive assembly on each of the front and rear axles. There are also many types of electric drive assemblies, including permanent magnet power assemblies driven by permanent magnet motors, asynchronous power assemblies driven by asynchronous motors, and electric excitation drive assemblies driven by electric excitation motors. Permanent magnet motors, asynchronous motors, and electric excitation motors all refer to permanent magnet motors, asynchronous motors, and electric excitation synchronous motors in the conventional sense as defined in "Electric Motors". Among them, asynchronous motors are also called induction motors. There are already many four-wheel drive configurations on the market and in published invention patents, including: front and rear dual permanent magnet electric drive configurations, permanent magnet + asynchronous dual electric drive configurations, permanent magnet + electric excitation electric drive configurations, etc.

[0004] like Figure 1 As shown, early electric vehicles mostly adopted the dual permanent magnet electric drive configuration. The dual permanent magnet electric drive configuration is the simplest, and its characteristics are that the front and rear electric drives are mostly of the same power and size, and the front and rear electric drives are platform-based. Since the magnetic field inside the permanent magnet motor 1 is generated by the permanent magnet installed on the motor rotor, it has the characteristic of being unable to be turned off, and the magnetic field that cannot be turned off will generate eddy current losses in the stator core of the motor. Therefore, whether the vehicle is under heavy load, light load, or even gliding state, the two motors are working at the same time, which brings additional energy loss and reduces the cruising range. Generally, the dual permanent magnet four-wheel drive configuration with the same battery power will have a cruising range that is about 10% lower than that of the two-wheel drive configuration. Some models will add a disengagement device to the output half shaft of the permanent magnet electric drive assembly on the front axle, and the front drive will be disengaged in the economic mode to obtain higher efficiency. Even so, the dual permanent magnet electric drive configuration with the front axle disengagement function will not have a comprehensive efficiency greater than that of the single permanent magnet two-wheel drive model. The cruising range of the four-wheel drive is still not higher than that of the two-wheel drive model

[0005] like Figure 2As shown in the figure, the current hot spot in the industry is the permanent magnet + asynchronous dual electric drive configuration, that is, the main drive (usually the rear drive, in order to facilitate the platform with the two-wheel drive model) uses a permanent magnet motor 1, and the auxiliary drive uses an asynchronous induction motor 2. This configuration can better solve the problem of dual permanent magnet motors, making the cruising range of four-wheel drive and two-wheel drive with the same power close, but the cruising range of four-wheel drive is still lower than that of two-wheel drive models.

[0006] Permanent magnet + electric excitation motor configuration is similar to the above-mentioned permanent magnet + asynchronous electric drive configuration. The four-wheel drive has a slightly lower range than the two-wheel drive model.

[0007] Generally speaking, four-wheel drive models are high-end models in the model spectrum, and the cruising range of high-end models is lower than that of mid- and low-end two-wheel drive models, which is a pain point for major automakers. Summary of the invention

[0008] The purpose of the present invention is to provide an electric drive four-wheel drive control method, an electric drive four-wheel drive architecture system and a new energy vehicle, so as to solve the technical problem in the prior art that the cruising range of four-wheel drive electric vehicles is lower than that of two-wheel drive electric vehicles.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] The present invention provides an electric drive four-wheel drive architecture system, which is a front and rear dual permanent magnet four-wheel drive architecture, comprising:

[0011] The front permanent magnet motor is installed on the front axle to form front drive;

[0012] A rear permanent magnet motor with a disengagement device is installed on the rear axle to form rear drive;

[0013] The front permanent magnet motor and the rear permanent magnet motor are both non-platform design structures, and their power and torque are different.

[0014] As a further improvement of the present invention, the power and torque of the rear permanent magnet motor are greater than the power and torque of the front permanent magnet motor.

[0015] As a further improvement of the present invention, when in a low-speed application scenario, the disengagement device on the rear permanent magnet motor is in an engaged state.

[0016] As a further improvement of the present invention, when in a high-speed application scenario, the disengagement device on the rear permanent magnet motor is in an off state.

[0017] As a further improvement of the present invention, the number of pole pairs of the rear permanent magnet motor is greater than the number of pole pairs of the front permanent magnet motor.

[0018] As a further improvement of the present invention, the disengagement device is any one of a half-shaft disengagement device, a reducer intermediate shaft disengagement device, and a reducer input shaft disengagement device.

[0019] The electric drive four-wheel drive architecture system of the present invention adopts a front and rear dual permanent magnet four-wheel drive architecture, and the front and rear drive motors are not of platform design. The power and torque of the two motors are significantly larger, and one is equipped with a disengagement device. It is mainly used in relatively low-speed application scenarios, such as urban roads, and is generally arranged on the rear axle, i.e., rear-wheel drive; the power and torque of the other motor are significantly smaller, and it is installed on the front axle, i.e., front-wheel drive. It has the characteristics of high efficiency at high speeds and has no disengagement device, so it is always in a driving (or feedback) state, which makes the cruising range of the four-wheel drive model better than that of the two-wheel drive model with the same power.

[0020] The present invention provides a new energy vehicle, comprising the electric drive four-wheel drive architecture system.

[0021] As a further improvement of the present invention, the new energy vehicle includes a vehicle controller, a front and rear torque distributor, a front motor controller and a rear motor controller.

[0022] The new energy vehicle of the present invention, in low-speed application scenarios such as urban roads, the disengagement device of the rear drive is in an engaged state, so that the power of the whole vehicle is guaranteed. In scenarios such as urban expressways and highways, the disengagement device of the rear drive is in an off state, so that the whole vehicle is mainly driven by the small motor of the front drive. At this time, on the one hand, the motor of the rear drive no longer rotates with the whole vehicle, eliminating the loss caused by the permanent magnetic field; on the other hand, the small motor of the front drive will be in a state with a higher load rate, and the working point will be in an area with higher motor efficiency, so the overall efficiency is better. The carefully designed front and rear drive motors, combined with the calibrated engagement strategy of the rear drive motor disconnection device, will achieve the effect that the efficiency of four-wheel drive is better than that of two-wheel drive.

[0023] The present invention provides an electric drive four-wheel drive control method, a method for controlling the new energy vehicle, the method comprising:

[0024] Execute a disengagement strategy with a disengagement device configured only on the rear permanent magnet motor, including:

[0025] When the vehicle is in sports mode, the disengagement device controlling the rear drive is in a long-term engagement state to ensure the vehicle's dynamic performance and quick response;

[0026] When the vehicle is in the economy mode or energy-saving mode, the different proportions of the front and rear drive output are coordinated according to the loss distribution characteristics of the front and rear drive and the stability of the vehicle, including:

[0027] Analyze the required torque at the wheel end;

[0028] According to the analyzed wheel-end torque demand, the front-drive output torque and rear-drive output torque are adjusted, that is, the overall torque demand of the vehicle will be unevenly distributed on the front and rear axles. Through optimal calibration, there is a situation where the rear drive is completely shut down or a certain percentage of the overall torque demand is output;

[0029] When the torque demand of the rear drive is not zero, maintaining the engagement state of the disengagement device of the rear drive;

[0030] When the torque demand of the rear drive is zero, the disconnecting device controlling the rear drive is disengaged.

[0031] As a further improvement of the present invention, a certain hysteresis loop or hysteresis strategy is applied when controlling the engagement and disengagement of the disengagement device of the rear drive.

[0032] The electric drive four-wheel drive control method provided by the present invention, through the careful design of the front and rear drive motors, combined with the calibrated engagement strategy of the rear drive motor disconnection device, will achieve the effect that the four-wheel drive efficiency is better than the two-wheel drive. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 It is a dual permanent magnet electric drive configuration structure in the prior art;

[0035] Figure 2 It is a permanent magnet + asynchronous dual electric drive configuration structure in the existing technology;

[0036] Figure 3 It is a schematic diagram of the structure of the electric drive four-wheel drive architecture system of the present invention;

[0037] Figure 4 It is a schematic diagram of the effect that can be achieved by the electric drive four-wheel drive architecture system of the present invention.

[0038] In the figure, 1 is a permanent magnet motor; 2 is an asynchronous induction motor; 3 is a disconnecting device; 4 is a reducer; 5 is a front permanent magnet motor; and 6 is a rear permanent magnet motor. DETAILED DESCRIPTION

[0039] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0040] like Figure 3 As shown, the present invention provides an electric drive four-wheel drive architecture system, which is a front and rear dual permanent magnet four-wheel drive architecture system, which can be applied to new energy vehicles. Specifically, the front and rear dual permanent magnet four-wheel drive architecture system includes:

[0041] A front permanent magnet motor 5 is installed on the front axle to form a front drive, and is used to drive the front wheels of the vehicle;

[0042] A rear permanent magnet motor 6 with a disengagement device 3 is installed on the rear axle to form a rear drive for driving the rear wheels of the vehicle;

[0043] Both the front permanent magnet motor 5 and the rear permanent magnet motor 6 are non-platform design structures, and their power and torque are different.

[0044] Specifically, in the present embodiment, the power and torque of the rear permanent magnet motor 6 are greater than the power and torque of the front permanent magnet motor 5 .

[0045] The electric drive four-wheel drive architecture system provided by the present invention adopts a front and rear dual permanent magnet four-wheel drive architecture, and the front and rear drive motors are not of platform design. The power and torque of the two motors are significantly larger, and one is equipped with a disengagement device. It is mainly used in relatively low-speed application scenarios, such as urban roads, and is generally arranged on the rear axle, that is, rear-wheel drive; the power and torque of the other motor are significantly smaller, and it is installed on the front axle, that is, front-wheel drive, and has the characteristics of high efficiency at high speeds. It has no disengagement device, so it is always in a driving (or feedback) state, so that the cruising range of the four-wheel drive model is better than that of the two-wheel drive model with the same power.

[0046] Furthermore, in the electric drive four-wheel drive architecture system of the present invention, when in a low-speed application scenario, the disengagement device on the rear permanent magnet motor is in an engaged state, so that the power performance of the whole vehicle can be guaranteed. When in a high-speed application scenario (urban expressway, highway, etc.), the disengagement device on the rear permanent magnet motor is in an off state, so that the whole vehicle is mainly driven by the small motor of the front drive. At this time, on the one hand, the rear-drive motor no longer rotates with the whole vehicle, eliminating the loss caused by the permanent magnetic field; on the other hand, the small motor of the front drive will be in a state with a higher load rate, and the working point will be in an area with higher motor efficiency, so the overall efficiency is better. After careful design of the front and rear drive motors, combined with the calibrated engagement strategy of the rear drive motor disconnection device, the effect of four-wheel drive efficiency being better than two-wheel drive will be achieved.

[0047] In order to achieve the above effect, the front and rear drive motors will have the following characteristics: the pole pair number of the rear permanent magnet motor 6 is greater than the pole pair number of the front permanent magnet motor 5. The purpose is: the rear drive motor adopts a larger pole pair number to ensure that the motor has a strong output capacity at low speed, and because of the effect of the disengagement device, there is no need to consider the loss problem caused by the high pole pair number at high speed. The front drive motor adopts a smaller pole pair number to ensure that the motor efficiency can be at a higher level during high-speed cruising, and because the rear drive motor guarantees the power at low speed, there is no need to worry about the relatively insufficient output caused by the small pole pair number.

[0048] Furthermore, the disengaging device applied by the present invention may be various types of disengaging devices, including a half-shaft disengaging device disengaged from a half-shaft, a reducer intermediate shaft disengaging device disengaged from a reducer intermediate shaft, and a reducer input shaft disengaging device disengaged from a reducer input shaft. The purpose of the present invention is to use a disengaging device to achieve an overall excellent four-wheel drive configuration, rather than to invent a disengaging device, so the specific structure of the disengaging device will not be described in detail here.

[0049] The electric drive four-wheel drive architecture system of the present invention provides a new energy vehicle, including the electric drive four-wheel drive architecture system.

[0050] As a further improvement of the present invention, the new energy vehicle includes a vehicle controller, a front and rear torque distributor, a front motor controller and a rear motor controller.

[0051] The new energy vehicle of the present invention, in low-speed application scenarios such as urban roads, the disengagement device of the rear drive is in an engaged state, so that the power of the whole vehicle is guaranteed. In scenarios such as urban expressways and highways, the disengagement device of the rear drive is in an off state, so that the whole vehicle is mainly driven by the small motor of the front drive. At this time, on the one hand, the motor of the rear drive no longer rotates with the whole vehicle, eliminating the loss caused by the permanent magnetic field; on the other hand, the small motor of the front drive will be in a state with a higher load rate, and the working point will be in an area with higher motor efficiency, so the overall efficiency is better. The carefully designed front and rear drive motors, combined with the calibrated engagement strategy of the rear drive motor disconnection device, will achieve the effect that the efficiency of four-wheel drive is better than that of two-wheel drive.

[0052] The four-wheel drive belt release device finally achieves the following effect: Figure 4 As shown in the figure, it can be seen that there are two high-efficiency areas, the high-efficiency area in the low-speed area (located on the left part of the figure), which corresponds to the urban working condition; the high-efficiency area in the high-speed area (located on the right part of the figure), which corresponds to the high-speed cruising working condition. These two areas correspond to the common working areas of the electric drive assembly for passenger cars. Because the efficiency of these two areas is relatively high, and the synthetic high-efficiency area of ​​the two drive assemblies that do not adopt the technology of the present invention is only one, the present invention can improve the driving efficiency of the system and increase the cruising range.

[0053] The present invention provides an electric drive four-wheel drive control method, a method for controlling a new energy vehicle, the method comprising:

[0054] Execute a disengagement strategy with a disengagement device configured only on the rear permanent magnet motor, including:

[0055] Step S1, when the vehicle is in a sports mode or other similar modes with different names, the disengagement device of the rear drive is controlled to be in a long-term engagement state to ensure the power and rapid response of the vehicle;

[0056] Step S2: When the vehicle is in the economy mode, energy-saving mode or other similar modes with different names, the engagement strategy of the rear-drive disengagement device will comprehensively consider the loss distribution characteristics of the front and rear drives and the stability of the vehicle, and coordinate the different proportions of the front and rear drive outputs, including:

[0057] Analyze the required torque at the wheel end;

[0058] According to the analyzed wheel end required torque, the front drive output torque and the rear drive output torque are adjusted; it should be noted here that the front and rear output torque adjustment action can be completed by the vehicle controller, the front motor controller, the rear motor controller or the front and rear torque distributor;

[0059] When the torque demand of the rear drive is not zero, maintaining the engagement state of the disengagement device of the rear drive;

[0060] When the torque demand of the rear drive is zero, the disconnecting device controlling the rear drive is disengaged.

[0061] For example, if the vehicle controller analyzes that the wheel end torque requirement is 2000Nm, the front and rear drive torque distributors (this work can be completed by the vehicle controller, front motor controller or rear motor controller) can change the front drive output torque between 0 and 2000Nm, and the rear drive will follow between 2000Nm and 0. When the rear drive torque requirement is 0, the rear drive can trigger the disengagement device to disengage the rear drive.

[0062] In actual operation, factors such as the smoothness of the vehicle should be considered, and a certain "hysteresis" or "hysteresis" should be imposed on the disengagement strategy when controlling the engagement and disengagement of the rear-wheel drive disengagement device.

[0063] The electric drive four-wheel drive control method provided by the present invention, through the careful design of the front and rear drive motors, combined with the calibrated engagement strategy of the rear drive motor disconnection device, will achieve the effect that the four-wheel drive efficiency is better than the two-wheel drive.

[0064] First of all, it should be explained here that “inward” refers to the direction toward the center of the accommodating space, and “outward” refers to the direction away from the center of the accommodating space.

[0065] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate directions or positional relationships based on the attached Figure 1 The orientation or positional relationship shown is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0066] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0067] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0069] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0070] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An electric drive four-wheel drive architecture system, characterized in that: It is a front and rear dual permanent magnet four-wheel drive architecture, including: The front permanent magnet motor is installed on the front axle to form front drive; A rear permanent magnet motor with a disengagement device is installed on the rear axle to form rear drive; The front permanent magnet motor and the rear permanent magnet motor are both non-platform design structures, and their power and torque are different.

2. The electric drive four-wheel drive architecture system according to claim 1, characterized in that: The power and torque of the rear permanent magnet motor are greater than the power and torque of the front permanent magnet motor.

3. The electric drive four-wheel drive architecture system according to claim 1, characterized in that: When in a low-speed application scenario, the disengagement device on the rear permanent magnet motor is in an engaged state.

4. The electric drive four-wheel drive architecture system according to claim 1, characterized in that: When in a high-speed application scenario, the disconnecting device on the rear permanent magnet motor is in an off state.

5. The electric drive four-wheel drive architecture system according to claim 2, characterized in that: The number of pole pairs of the rear permanent magnet motor is greater than the number of pole pairs of the front permanent magnet motor.

6. The electric drive four-wheel drive architecture system according to claim 1, characterized in that: The disengaging device is any one of a half-shaft disengaging device, a speed reducer intermediate shaft disengaging device, and a speed reducer input shaft disengaging device.

7. A new energy vehicle, characterized in that: Comprising an electric drive four-wheel drive architecture system as described in any one of claims 1-6.

8. The new energy vehicle according to claim 7, characterized in that: The new energy vehicle includes a vehicle controller, a front and rear torque distributor, a front motor controller and a rear motor controller.

9. An electric four-wheel drive control method, characterized in that: A method for controlling a new energy vehicle according to any one of claims 7 to 8, the method comprising: Execute a disengagement strategy with a disengagement device configured only on the rear permanent magnet motor, including: When the vehicle is in sports mode, the disengagement device controlling the rear drive is in a long-term engagement state to ensure the vehicle's dynamic performance and quick response; When the vehicle is in the economy mode or energy-saving mode, the different proportions of the front and rear drive output are coordinated according to the loss distribution characteristics of the front and rear drive and the stability of the vehicle, including: Analyze the required torque at the wheel end; According to the analyzed wheel end required torque, the front drive output torque and the rear drive output torque are adjusted; When the torque demand of the rear drive is not zero, maintaining the engagement state of the disengagement device of the rear drive; When the torque demand of the rear drive is zero, the disconnecting device controlling the rear drive is disengaged.

10. The method according to claim 9, characterized in that When controlling the engagement and disengagement of the disengagement device of the rear drive, a certain hysteresis loop or hysteresis strategy is applied.

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