Off-road control method for a multi-operating mode hybrid vehicle and vehicle

Abstract

The present application provides an off-road control method of a multi-operation mode hybrid vehicle and the vehicle. The multi-operation mode hybrid vehicle has an engine and a first motor for driving front axle wheels, a second motor for driving rear axle wheels, and a battery connected with the first motor and the second motor. The control method comprises: configuring two modes and four-wheel drive mode for the vehicle by matching different operation states of the engine, the first motor and the second motor; acquiring the accelerator pedal opening degree of the vehicle, the current working condition scene of the vehicle, and the wheel speed of the driving wheels and the driven wheels in real time; and switching the two modes to the four-wheel drive mode when the set off-road preset condition is met. The off-road control method of the multi-operation mode hybrid vehicle is beneficial to improve the accuracy and effectiveness of the four-wheel drive mode switching, thereby improving the comprehensive driving efficiency of the hybrid vehicle.

Description

Technical Field

[0001] This invention relates to the field of hybrid vehicle technology, and particularly to an off-road control method for a multi-mode hybrid vehicle. Additionally, this invention also relates to a vehicle. Background Technology

[0002] With the rapid development of the automotive industry, the country has increasingly higher requirements for the economy and emissions of automobiles. Due to the excellent power, economy and effective reduction of exhaust emissions of hybrid vehicles, hybrid vehicles have become a rapidly developing type of vehicle in the automotive field; and the research and development investment in hybrid system architecture in this field is also increasing.

[0003] Currently, there are many types of hybrid transmissions on the market, and they have been applied to various passenger vehicles. However, existing hybrid transmission systems still have many shortcomings in terms of gear configuration, drive mode settings, and drive mode control. For example, commonly used transmissions have only single or two gears, which are relatively low, resulting in poor vehicle power and fuel economy when the engine is running. Furthermore, the control modes of the entire hybrid system are limited; most hybrid transmissions are front-wheel drive, with a relatively simple drive mode. This means that the vehicle lacks suitable drive control strategies for special operating conditions, resulting in poor performance and handling.

[0004] Meanwhile, when in complex road conditions such as mud, rain, or snow, the vehicle needs to switch to four-wheel drive mode in real time. However, the existing control strategy lacks consideration of the actual torque demand of the wheels, often failing to accurately and effectively utilize the four-wheel drive mode and leading to unnecessary frequent switching between two-wheel drive and four-wheel drive.

[0005] Based on the above, it is necessary to conduct targeted and in-depth research on the drive control strategies and methods of hybrid systems in order to continuously optimize and improve the driving economy and overall driving performance of hybrid vehicles. Summary of the Invention

[0006] In view of this, the present invention aims to propose an off-road control method for hybrid vehicles with multiple operating modes, so as to improve the accuracy, timeliness and effectiveness of the switching between two-wheel drive mode and four-wheel drive mode of hybrid vehicles, thereby improving the overall driving efficiency of hybrid vehicles.

[0007] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0008] An off-road control method for a multi-mode hybrid vehicle, the multi-mode hybrid vehicle having an engine and a first motor for driving the front axle wheels, a second motor for driving the rear axle wheels, and a battery connecting the first motor and the second motor.

[0009] The control method includes configuring multiple operating modes for the vehicle by matching different operating states of the engine, the first motor and the second motor, and the operating modes include a two-wheel drive mode in which only the front axle wheels or the rear axle wheels are driven, and a four-wheel drive mode in which both the front axle wheels and the rear axle wheels are driven.

[0010] The system acquires real-time information on the vehicle's accelerator pedal opening, current operating conditions, and wheel speeds of both the active and driven wheels. When the following off-road preset conditions are met, the system switches from two-wheel drive mode to four-wheel drive mode:

[0011] The rate of change of the accelerator pedal opening rises above a set threshold and remains there for a set time, or the working condition is determined to be an off-road condition.

[0012] The difference between the rotational speed of the driving wheel and the rotational speed of the driven wheel is above a set rotational speed difference.

[0013] Furthermore, the operating modes include a pure electric mode in which the vehicle is driven by the first motor and / or the second motor, an engine mode in which the engine provides power output, and a hybrid mode in which the engine, in conjunction with the first motor or the second motor, drives the vehicle. The control method further includes: acquiring the battery charge level of the battery and sequentially preset a first charge level and a second charge level from high to low; executing the pure electric mode when the battery charge level is above the first charge level, executing the engine mode when the battery charge level is below the second charge level, and executing the hybrid mode when the battery charge level is between the first charge level and the second charge level.

[0014] Furthermore, the pure electric mode includes an electric front-wheel drive mode and an electric rear-wheel drive mode corresponding to the two-wheel drive mode, and an electric four-wheel drive mode corresponding to the four-wheel drive mode; the hybrid mode includes a hybrid front-wheel drive mode corresponding to the two-wheel drive mode, and a hybrid four-wheel drive mode corresponding to the four-wheel drive mode; when the off-road preset conditions are met, the current vehicle speed is obtained, and when the vehicle speed is higher than the preset speed value, the system switches to the hybrid four-wheel drive mode, and when the vehicle speed is lower than the preset speed value, the system switches to the electric four-wheel drive mode.

[0015] Furthermore, the engine modes include an engine direct drive mode where the engine drives the front axle wheels via the transmission, a series mode where the engine drives the first motor to generate electricity and the second motor drives the rear axle wheels, and an idle power generation mode where only the engine drives the first motor to generate electricity; the control method further includes: acquiring the vehicle speed; in the engine modes, when the vehicle speed of a moving vehicle is greater than the set speed, the engine direct drive mode is executed; when the vehicle speed is less than or equal to the set speed, the series mode is executed; and when the vehicle is idling, the idle power generation mode is executed.

[0016] Furthermore, the operating mode includes a launch start mode, in which the engine and the first motor jointly drive the front axle wheels, and the second motor drives the rear axle wheels; the control method further includes: acquiring the accelerator pedal opening, and executing the launch start mode when the accelerator pedal opening reaches a set opening value.

[0017] Furthermore, the operating mode includes an energy recovery mode in which the first motor is driven by the front axle wheels and / or the second motor is driven by the rear axle wheels to generate electricity; the control method further includes: determining whether the vehicle is in a braking or coasting state, and whether the operating scenario is an intelligent following scenario; when any of the following preset conditions are met, the vehicle executes the energy recovery mode:

[0018] The vehicle is in a braking or coasting state;

[0019] The vehicle is in a smart following scenario, and the current following distance is within the preset following distance range.

[0020] Furthermore, the energy recovery modes include a front axle energy recovery mode in which the first motor is driven by the front axle wheels to generate electricity, a rear axle energy recovery mode in which the second motor is driven by the rear axle wheels to generate electricity, and a dual-axle energy recovery mode in which the first motor and the second motor are driven by the front axle wheels and the rear axle wheels respectively to generate electricity.

[0021] Furthermore, it also includes: in the braking state, obtaining the opening degree of the brake pedal; if the opening degree of the brake pedal is less than or equal to a first set opening degree value, controlling the vehicle to operate in the rear axle energy recovery mode; if the opening degree of the brake pedal is greater than a second set opening degree value, controlling the vehicle to operate in the dual axle energy recovery mode; the second set opening degree value is greater than the first set opening degree value.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] The off-road control method for multi-mode hybrid vehicles of the present invention is based on the configuration condition that the front axle wheels and the rear axle wheels of the vehicle can be driven separately. During normal driving, it adopts a two-wheel drive mode of front-wheel drive or rear-wheel drive mode. When rapid acceleration or getting out of trouble is required, it switches to four-wheel drive mode in real time and accurately. By judging the difference in wheel speed between the front axle wheels and the rear axle wheels before switching, the actual driving torque demand of the front axle wheels and the rear axle wheels can be determined, so as to determine the necessity, accuracy and effectiveness of four-wheel drive mode switching, thereby improving the overall driving efficiency of hybrid vehicles.

[0024] Furthermore, by selecting pure electric mode, hybrid mode, or engine mode based on the current battery charge level, the system can fully utilize the battery's energy storage while effectively preventing depletion of the battery, thus balancing vehicle economy and reliability. Simultaneously, switching between two-wheel drive and four-wheel drive within the corresponding pure electric or hybrid mode helps maintain the stability of the battery's power output and reduces the frequency of engagement of transmission mechanisms such as the gearbox, thereby further improving the operational stability and economy of the hybrid system.

[0025] Another object of the present invention is to provide a vehicle driven by a hybrid system, wherein the hybrid system employs the off-road control method for multi-mode hybrid vehicles described in the present invention.

[0026] Furthermore, the first motor is driven by the engine, and both the first motor and the engine are connected to the front axle wheels via a transmission device; the transmission device includes an input shaft and an output shaft arranged in parallel, and a shifting mechanism; the engine is connected to the input shaft via a cut-off mechanism, the first motor is driven by the input shaft, the output shaft is driven by the front axle wheels, and multiple shift gear sets are provided between the input shaft and the output shaft; the shifting mechanism can select one of the shift gear sets to form a transmission connection between the input shaft and the output shaft.

[0027] The vehicle of the present invention is equipped with an engine, a first motor and a second motor. The engine can drive the front axle wheels through a transmission device, the first motor can generate electricity or output power to drive the front axle wheels under the drive of the engine, and the second motor can directly drive the rear axle wheels. This provides a hybrid architecture that can be matched with multiple operating modes, enabling the vehicle to match multiple different power drive operating modes, and providing a good hardware foundation for enriching the vehicle's drive operating modes and reducing the overall drive efficiency of the vehicle. Attached Figure Description

[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are for explaining the invention. The directional terms used, such as front / back, up / down, etc., are only used to indicate relative positional relationships and do not constitute an improper limitation of the invention. In the drawings:

[0029] Figure 1 This is a schematic diagram of the system configuration of the hybrid system of the multi-operating-mode hybrid vehicle described in Embodiment 1 of the present invention;

[0030] Figure 2 This is a schematic diagram of the control logic for determining off-road preset conditions in the control method for a multi-operation mode hybrid vehicle according to Embodiment 1 of the present invention;

[0031] Figure 3 This is a schematic diagram of the overall operation mode control logic of the control method described in Embodiment 1 of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 11. Front axle wheels; 12. Rear axle wheels;

[0034] 20. Engine; 21. First motor; 22. Second motor; 23. Reducer; 24. Differential; 25. Battery;

[0035] 301. First input shaft; 302. Second input shaft; 311. Main output shaft; 312. Auxiliary output shaft; 321. First gear set; 322. Second gear set; 323. Third gear set; 324. Fourth gear set; 325. Reverse gear transmission gear; 326. Reverse output gear; 327. Forward gear output gear; 328. Front axle gear; 329. Parking gear; 33. Motor drive gear set;

[0036] 411. First clutch; 412. Second clutch; 421. First synchronizer; 422. Second synchronizer. Detailed Implementation

[0037] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0038] In the description of this invention, it should be stated that the use of terms such as "up," "down," "left," "right," "front," "rear," "inner," and "outer" to indicate orientation or positional relationships is based on the orientation or positional relationships shown in the accompanying drawings and is only for the convenience of describing this invention. It does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed or operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Taking the automobile described in this invention as an example, the directional terms such as "up," "down," "left," "right," "front," and "rear" used in the embodiments are defined based on the vehicle's vertical direction (also known as the height direction), horizontal direction (also known as the width direction), and front-back direction (also known as the length direction). Specifically, as shown in the accompanying drawings, the X direction is the vehicle's front-back direction, where the side pointed by the arrow is "front," and vice versa. The Y direction is the vehicle's horizontal direction, where the side pointed by the arrow is "left," and vice versa. The Z direction is the vehicle's vertical direction, where the side pointed by the arrow is "up," and vice versa. "Inner" and "outer" are defined based on the outline of the corresponding components. For example, "inner" and "outer" are defined based on the outline of the vehicle. The side of the vehicle outline closer to the middle of the vehicle is "inner", and the other side is "outer".

[0039] Furthermore, in the description of this invention, unless otherwise explicitly defined, the terms "installation," "connection," "linking," and "connector" should be interpreted broadly. For example, a connection 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, or it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention in light of the specific circumstances. The limiting terms such as "first," "second," "A," "B," "C," and "D" appearing in the description of this invention are merely for distinguishing similar features in different locations, attributions, or uses, in order to avoid ambiguity and confusion, and should not be construed as indicating or implying relative importance.

[0040] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0041] Example 1

[0042] This embodiment relates to an off-road control method for a multi-mode hybrid vehicle, which can improve the accuracy, timeliness, and effectiveness of the hybrid vehicle's switching between two-wheel drive and four-wheel drive modes, thereby improving the overall driving efficiency of the hybrid vehicle; an exemplary system configuration of the hybrid system to which this off-road control method is applicable is as follows: Figure 1 As shown, an exemplary control logic of this off-road control method is as follows: Figure 2 and Figure 3 As shown.

[0043] Overall, this multi-mode hybrid vehicle has an engine 20 and a first motor 21 for driving the front axle wheels 11, a second motor 22 for driving the rear axle wheels 12, and a battery 25 connecting the first motor 21 and the second motor 22. The control method includes configuring multiple operating modes for the vehicle by matching different operating states of the engine 20, the first motor 21, and the second motor 22. These operating modes include a two-wheel drive mode where only the front axle wheels 11 or the rear axle wheels 12 are driven, and a four-wheel drive mode where both the front axle wheels 11 and the rear axle wheels 12 are driven. Based on this, the vehicle's accelerator pedal opening, the vehicle's current operating condition, and the wheel speeds of the active and driven wheels are acquired in real time. When the following off-road preset conditions are met, the two-wheel drive mode is switched to four-wheel drive mode:

[0044] Off-road preset condition 1: The rate of change of accelerator pedal opening rises above a set threshold and remains there for a set time, or the working condition is determined to be an off-road condition.

[0045] Off-road preset condition two: The difference between the wheel speed of the driving wheel and the wheel speed of the driven wheel is above the set speed difference.

[0046] The mode will be switched when both of the above conditions are met.

[0047] Specifically, the two-wheel drive modes include a front-wheel drive mode where only the front axle wheels 11 are driven, and a rear-wheel drive mode where only the rear axle wheels 12 are driven. When the current mode is front-wheel drive, and the difference between the wheel speed of the front axle wheels 11 and the wheel speed of the rear axle wheels 12 is greater than a set speed difference; or, when the current mode is rear-wheel drive, and the difference between the wheel speed of the rear axle wheels 12 and the wheel speed of the front axle wheels 11 is greater than a set speed difference, both satisfy off-road preset condition two.

[0048] To facilitate understanding of the control method in this embodiment, we will first combine... Figure 1 The general configuration of the hybrid system targeted by this off-road control method is described; however, it should be noted that the exemplary description of the specific configuration of the hybrid system in this embodiment does not constitute a limitation on the scope of protection of the off-road control method of the present invention.

[0049] The hybrid system of this embodiment is configured on a four-wheeled hybrid vehicle, specifically two front axle wheels 11 and two rear axle wheels 12. The rear axle wheels 12 are driven by a second motor 22, which is connected to the drive shaft of the rear axle wheels 12 via a reducer 23. The drive shaft of the front axle wheels 11 is equipped with a transmission device with multiple switchable gears. The engine 20 drives the front axle wheels 11 through the transmission device to achieve multi-gear drive control of the vehicle. A cut-off mechanism is provided between the engine 20 and the transmission device. This cut-off mechanism can be, for example, […]. Figure 1 The first clutch 411, or a dog clutch, shown is used to disengage the engine 20 during pure electric drive. The first motor 21 can be directly connected to the drive shaft of the front axle wheel 11, or connected to the front axle wheel 11 via a transmission device to drive the front axle wheel 11. At the same time, the first motor 21 must be connected to the engine 20 so that it can generate electricity under the drive of the engine 20 to replenish the battery 25.

[0050] Referring to the configuration of the hybrid system described above, this embodiment has different mode matching methods for its operating modes, allowing for the setting of multiple different operating modes. For each operating mode, multiple preset conditions related to the vehicle's operating parameters can be set; subsequently, changes in the operating parameters are acquired in real time, and the vehicle is controlled to operate in the operating mode corresponding to the preset conditions that meet the operating parameters.

[0051] like Figure 3 As shown, from the perspective of pure electric drive and engine drive, the operating modes can be divided into three main categories: pure electric mode, hybrid mode, and engine mode. Pure electric mode can be further subdivided into electric rear-wheel drive mode, electric front-wheel drive mode, and electric four-wheel drive mode. Hybrid mode can be subdivided into hybrid front-wheel drive mode and hybrid four-wheel drive mode. Engine mode can be subdivided into engine direct drive mode, series drive mode, and idle-speed generator mode. From the perspective of primary and secondary drive and four-wheel drive of the front axle wheels 11 and rear axle wheels 12, the operating modes can be divided into two main categories: two-wheel drive mode and four-wheel drive mode. The aforementioned electric rear-wheel drive mode, electric front-wheel drive mode, hybrid front-wheel drive mode, engine direct drive mode, and series drive mode all belong to two-wheel drive mode, while the aforementioned electric four-wheel drive mode and hybrid four-wheel drive mode both belong to four-wheel drive mode.

[0052] Based on the above classification, in pure electric mode, front-wheel drive mode corresponds to electric front-wheel drive mode, rear-wheel drive mode corresponds to electric rear-wheel drive mode, and four-wheel drive mode corresponds to electric four-wheel drive mode. When off-road preset conditions are met, it is preferable to switch from electric front-wheel drive mode or electric rear-wheel drive mode to electric four-wheel drive mode. Similarly, in hybrid mode, front-wheel drive mode corresponds to hybrid front-wheel drive mode, and four-wheel drive mode corresponds to hybrid four-wheel drive mode. When off-road preset conditions are met, it is preferable to switch from hybrid front-wheel drive mode to hybrid four-wheel drive mode. Switching between two-wheel drive and four-wheel drive modes within the corresponding pure electric mode or hybrid mode helps maintain the stability of battery power output, reduces the frequency of engagement of transmission mechanisms such as the gearbox, and thus further improves the operating stability and economy of the hybrid system.

[0053] In addition, for special operating conditions of the vehicle, the operating modes may also include launch control mode and energy recovery mode; the specific configuration of the above operating modes and the status of related power components and transmission components can be found in the table below:

[0054]

[0055]

[0056] Specifically, in electric rear-wheel drive mode, the engine 20 is not working, the cut-off mechanism is in the off state, the first motor 21 is not working, the shift mechanism does not transmit power, and the front axle wheels 11 are in a driven state; at the same time, the second motor 22 runs and outputs power, and the rear axle wheels 12 are driven to move the vehicle.

[0057] In electric front-wheel drive mode, the engine 20 is not working, the cut-off mechanism is in the off state, the first motor 21 outputs power, the shift mechanism transmits power, and the front axle wheels 11 are driven to move the vehicle; at the same time, the second motor 22 is not working, and the rear axle wheels 12 are in a driven state.

[0058] In electric four-wheel drive mode, engine 20 is not working, the cut-off mechanism is in the off state, the first motor 21 outputs power, the shift mechanism transmits power, and the front axle wheels 11 are driven; at the same time, the second motor 22 operates and outputs power, and the rear axle wheels 12 are also driven, thus putting the vehicle in four-wheel drive mode.

[0059] In hybrid front-wheel drive mode, engine 20 is running, the cut-off mechanism is engaged, the first motor 21 outputs power, the shift mechanism transmits power, and the front axle wheels 11 are driven by engine 20 and the first motor 21 to move the vehicle; at the same time, the second motor 22 is not working, and the rear axle wheels 12 are in a driven state.

[0060] In hybrid four-wheel drive mode, engine 20 is running, the cut-off mechanism is engaged, the first motor 21 is not working, the shift mechanism transmits power, and the front axle wheels 11 are driven by engine 20; at the same time, the second motor 22 runs and outputs power, and the rear axle wheels 12 are also driven, thus putting the vehicle in four-wheel drive mode.

[0061] In engine direct drive mode, engine 20 is running, the cut-off mechanism is engaged, the first motor 21 is not working, the shift mechanism transmits power, and the front axle wheels 11 are driven by engine 20 to move the vehicle; at the same time, the second motor 22 is not working, and the rear axle wheels 12 are in a driven state.

[0062] In series mode, engine 20 is running, the cut-off mechanism is engaged, first motor 21 is running to generate electricity, shift mechanism does not transmit power, and front axle wheel 11 is in a driven state; at the same time, second motor 22 is running to output power, and rear axle wheel 12 is driven to move the vehicle.

[0063] In idle power generation mode, engine 20 is running, the cut-off mechanism is engaged, the shift mechanism does not transmit power, the front axle wheels 11 are stationary, and engine 20 only drives the first motor 21 to generate electricity; at the same time, the second motor 22 is not working, and the rear axle wheels 12 are stationary.

[0064] In launch control mode, engine 20 is running, the cut-off mechanism is engaged, first motor 21 outputs power, shift mechanism transmits power, front axle wheels 11 are driven by engine 20 and first motor 21 to move the vehicle; at the same time, second motor 22 operates to output power, rear axle wheels 12 are also driven, thus putting the vehicle in four-wheel drive mode.

[0065] In energy recovery mode, engine 20 is not operating, and the cut-off mechanism is in the disengaged state. The first motor 21 and the second motor 22 can operate and generate electricity under the respective drive of the front axle wheels 11 and the rear axle wheels 12. Specifically, this can be further divided into front axle energy recovery mode, rear axle energy recovery mode, and dual-axle energy recovery mode. When the vehicle is operating in front axle energy recovery mode, the cut-off mechanism cuts off power, the shift mechanism engages with the shift gear set, engine 20 is not operating, the first motor 21 operates and generates electricity under the drive of the front axle wheels 11, and the second motor 22 is not operating. When the vehicle is operating in rear axle energy recovery mode, the cut-off mechanism cuts off power, the shift mechanism disengages from the shift gear set, both engine 20 and the first motor 21 are not operating, and the second motor 22 operates and generates electricity under the drive of the rear axle wheels 12. When the vehicle is operating in dual-axle energy recovery mode, the cut-off mechanism cuts off power, the shift mechanism engages with the shift gear set, engine 20 is not operating, and the first motor 21 and the second motor 22 operate and generate electricity under the respective drive of the front axle wheels 11 and the rear axle wheels 12.

[0066] Based on the aforementioned rich operating mode settings of the vehicle, environmental parameters and operating parameters such as the speed and distance of the vehicle in front can be obtained through the vehicle's own GPS module, radar module, camera and other sensor devices to establish intelligent safety model data such as the overall vehicle safety distance; or, operating parameters such as motor torque, battery level, accelerator pedal opening, overall vehicle speed and wheel speed can be read from the vehicle control unit to comprehensively determine the appropriate operating mode for the current vehicle and control the vehicle to operate in the appropriate mode.

[0067] Specifically, such as Figure 3As shown, the operating parameters of this embodiment include the battery charge level detected by the battery 25, and the operating modes described above: pure electric mode, engine mode, and hybrid mode. The preset conditions include a first charge level and a second charge level set sequentially from high to low. Based on this, pure electric mode is executed when the battery charge level is above the first charge level, engine mode is executed when the battery charge level is below the second charge level, and hybrid mode is executed when the battery charge level is between the first and second charge levels. By selecting pure electric mode, hybrid mode, or engine mode according to the current battery charge level of the battery 25, the energy storage capacity of the battery 25 can be fully utilized while effectively preventing the battery 25 from running out of power, thus balancing the vehicle's operating economy and reliability, and improving the vehicle's fuel economy.

[0068] The aforementioned first and second battery capacity values ​​can be flexibly set within a reasonable range. For example, the first battery capacity value could refer to 60% of the total battery capacity; when the battery capacity is greater than or equal to 60%, it indicates that the vehicle's battery has sufficient power. Of course, the first battery capacity value could also refer to 40%, 50%, or 70% of the total battery capacity, depending on the battery capacity. When the battery capacity is relatively large, the first battery capacity value could be 30% or 20% of the total battery capacity, while when the battery capacity is relatively small, the first battery capacity value should be set higher. Similarly, provided that the second battery capacity value is lower than the first battery capacity value, it can be taken as 30%, 20%, or 10% of the total battery capacity, and can be flexibly adjusted according to the battery capacity.

[0069] It should be noted that in pure electric mode, it can be the aforementioned electric rear-wheel drive mode, electric front-wheel drive mode, or electric four-wheel drive mode. Preferably, the electric rear-wheel drive mode is used first; and the operating parameters also include detecting the motor fault signal acquired by the second motor 22. In the pure electric rear-wheel drive mode, when the motor fault signal is generated, the mode is switched to electric front-wheel drive mode.

[0070] Furthermore, the engine modes in this embodiment include the aforementioned engine direct drive mode, series mode, and idle power generation mode. Operating parameters also include vehicle speed, and preset conditions include a set vehicle speed. Based on this, in engine mode, the engine direct drive mode is executed when the vehicle speed is greater than the set speed, and the series mode is executed when the speed is less than or equal to the set speed (but not zero). When the vehicle speed is zero and the vehicle is idling, the vehicle executes the idle power generation mode. When the battery 25 has low remaining charge, using engine mode can prevent further battery charge loss. Simultaneously, by using engine direct drive mode, series mode, or idle power generation mode according to the vehicle's operation and overall vehicle speed, the vehicle can ensure the power required for operation while using the first motor 21 to convert redundant power output from the engine 20 into electrical energy to replenish the battery 25, thereby achieving a good battery charge replenishment effect.

[0071] Understandably, determining the appropriate operating mode based on the vehicle speed when the battery 25 is low allows for a better match between the vehicle's power requirements and the actual battery level. In this case, the vehicle speed is first acquired, and the system determines whether to use series mode or engine direct drive mode by checking if the speed exceeds a set speed. For example, the set speed could be 30 km / h. If the battery level is less than or equal to a second charge value, the vehicle operates in series mode when the speed is less than or equal to 30 km / h, and in engine direct drive mode when the speed is greater than 30 km / h. Of course, this set speed can be set to other values ​​as needed, such as 20 km / h, 40 km / h, or 50 km / h, but this embodiment does not impose specific limitations. Therefore, when the battery level is less than or equal to the second charge value and the vehicle speed is detected to be zero (idle), the vehicle can be controlled to operate in idle power generation mode. The vehicle controller sends a power generation request signal to the first motor 21, and the engine 20 drives the first motor 21 to generate electricity to charge the battery 25.

[0072] In addition, the operating parameters of this embodiment also include accelerator pedal opening, vehicle speed, and wheel speed. For example... Figure 3 As shown, when the rate of change of accelerator pedal opening rises above a set threshold, or when the wheel speed and vehicle speed are mismatched, it is preferable to switch the vehicle from the aforementioned two-wheel drive mode to four-wheel drive mode. Specifically, in pure electric mode, the vehicle switches from electric rear-wheel drive or electric front-wheel drive mode to electric four-wheel drive mode; in hybrid mode, it switches from hybrid front-wheel drive mode to hybrid four-wheel drive mode. Based on the changes in the rate of change of accelerator pedal opening or the matching of wheel speed and vehicle speed, timely switching from two-wheel drive mode to four-wheel drive mode helps improve the vehicle's off-road capability and allows it to adapt to different road conditions. Timely switching between two-wheel drive and four-wheel drive modes not only enables the vehicle to adapt to various complex road conditions and meet rapid acceleration requirements, but also maintains good vehicle economy.

[0073] The aforementioned accelerator pedal opening refers to the angle of the accelerator pedal, and the rate of change of the accelerator pedal opening refers to the speed at which the accelerator pedal is depressed. For example, if the accelerator pedal opening is represented by D, then the set threshold could be 0.1D per millisecond. In electric rear-wheel drive mode, when the rate of change of the accelerator pedal opening is greater than or equal to 0.1D per millisecond, the vehicle controller sends a front axle drive signal according to the accelerator pedal opening requirement, controlling the vehicle to switch to electric four-wheel drive mode; or, in hybrid front-wheel drive mode, it sends a rear axle drive signal, controlling the vehicle to switch to hybrid four-wheel drive mode. In this case, the electric four-wheel drive mode or hybrid four-wheel drive mode provides stronger power compared to the two-wheel drive mode, improving the user experience.

[0074] It should be noted that the above threshold setting is just an example. The threshold can also be other values, such as 0.05D per millisecond, 0.15D per millisecond, 0.2D per millisecond, etc. It can be set according to different situations, and there are no specific restrictions here.

[0075] In addition to switching the four-wheel drive mode according to the above-mentioned off-road preset condition one (the rate of change of accelerator pedal opening), such as Figure 2 As shown, close attention should also be paid to the mismatch between vehicle speed and wheel speed. As indicated in Off-Road Preset Condition Two of this embodiment, when the wheel urgently needing increased torque to escape a difficult situation is currently the drive wheel, while the driven wheels do not currently require increased torque, switching from the current two-wheel drive mode to four-wheel drive mode is meaningless. For example, if the current mode is front-wheel drive, and the front axle wheel 11 is in a state of obstruction requiring increased torque, while the rear axle wheel 12 is slipping and spinning freely, causing the wheel speed of the front axle wheel 11 to be lower than that of the rear axle wheel 12, then there is no need to switch to four-wheel drive mode; the current front-wheel drive mode should be maintained. Only when the wheel speed of the front axle wheel 11 is higher than that of the rear axle wheel 12, and the difference is above the set speed difference, indicating that the front axle wheel 11 is slipping and spinning freely while the rear axle wheel 12 is in a state of obstruction requiring increased torque, is it necessary to switch from the current front-wheel drive mode to four-wheel drive mode. The same principle applies to switching between rear-wheel drive and four-wheel drive modes, and will not be elaborated further here.

[0076] Generally, the vehicle speed and wheel speed are matched; that is, the wheel speed and the vehicle speed are consistent. If the vehicle speed and wheel speed are mismatched, it indicates that wheel slippage has occurred, such as slippage on snow or uneven ground. In this case, the vehicle can operate in electric four-wheel drive mode, outputting high torque to get out of trouble. The "set speed difference value" provides a basis for determining whether to select four-wheel drive mode under this condition. This wheel speed difference value can refer to the speed difference between the front axle wheel 11 and the rear axle wheel 12, or the speed difference between the left and right wheels of the front axle wheel 11, or the speed difference between the left and right wheels of the rear axle wheel 12. In this embodiment, the speed difference value between the front axle wheel 11 and the rear axle wheel 12 is used. The set speed difference value can be specifically set as needed; for example, the set speed difference value can be 10 to 20 revolutions per minute, or 3 to 5 revolutions per minute, etc.

[0077] Regarding the determination of a mismatch between vehicle speed and wheel speed, four-wheel drive mode is activated when off-road preset conditions are met. A preset speed value can also be set; when the vehicle speed exceeds the preset value, it switches to hybrid four-wheel drive mode, and when it falls below the preset speed value, it switches to electric four-wheel drive mode. The preset speed value can be flexibly selected between 15km / h and 50km / h, for example, 28km / h. This setting helps to leverage the superior driving efficiency of the engine under high-speed conditions, further improving the vehicle's operating economy.

[0078] In addition, the off-road control method in this embodiment also includes a launch start mode and an energy recovery mode. In launch start mode, the engine 20 and the first motor 21 jointly drive the front axle wheels 11, and the second motor 22 drives the rear axle wheels 12. Here, the operating parameters include the accelerator pedal opening, and the preset conditions include a set opening value. When the accelerator pedal opening reaches the set opening value, the launch start mode is executed. By setting the launch start mode, the engine 20, the first motor 21, and the second motor 22 are all engaged in driving the vehicle, which can effectively increase the vehicle's maximum output power, thereby meeting the rapid acceleration requirements during the vehicle's start-up phase and improving the vehicle's start-up acceleration performance.

[0079] When the accelerator pedal opening reaches the set value, a launch control command is issued, controlling the vehicle to operate in launch start mode. The set opening value can refer to the accelerator pedal being fully depressed, i.e., "floor throttle". At this time, the vehicle controller simultaneously sends drive signals to the engine 20, the first motor 21, and the second motor 22, controlling the vehicle to operate in launch start mode, where the vehicle's power is at its strongest, providing the driver with a push-back feeling.

[0080] The operating parameters of this embodiment also include a vehicle status signal for determining whether the vehicle is in a braking or coasting state. The operating scenarios of this embodiment also include an intelligent following scenario. The vehicle executes the energy recovery mode when any of the following preset conditions are met:

[0081] (1) The vehicle is in a braking or coasting state;

[0082] (2) The vehicle is in the intelligent following scenario and the current following distance is within the preset following distance range. When the vehicle is in neutral or braking, any one of the front axle energy recovery mode, rear axle energy recovery mode and dual axle energy recovery mode can be activated to charge the battery.

[0083] Under braking conditions, the steps for controlling the vehicle to execute the energy recovery mode include: obtaining the brake pedal opening; if the brake pedal opening is less than or equal to a first preset opening value, controlling the vehicle to operate in rear axle energy recovery mode; if the brake pedal opening is greater than a second preset opening value, controlling the vehicle to operate in dual-axle energy recovery mode. Here, the second preset opening value is greater than the first preset opening value, and when the brake pedal opening is between the first and second preset opening values, the front axle energy recovery mode can be executed.

[0084] "Brake pedal opening" can refer to the angle of the brake pedal. For example, if the brake pedal opening can be represented by d, then the "first set opening value" can be 60%d and the "second set opening value" can be 70%d. If the brake pedal opening is less than or equal to 60%d, the vehicle is controlled to operate in rear axle energy recovery mode, generating electricity through the second motor 22. If the brake pedal opening is greater than 70%d, the vehicle is controlled to operate in dual axle energy recovery mode, generating electricity through the first motor 21 and the second motor 22.

[0085] It should be noted that the first set opening value and the second set opening value can also be equal. The first set opening value and the second set opening value are not limited to the above examples, and can also be other values. For example, the first set opening value is 40%d, 50%d, etc., and the second set opening value is 80%d, 85%d, 90%d. They can be set according to the situation, and there are no specific restrictions here.

[0086] When a vehicle is in motion, if it detects a vehicle within a predetermined distance range ahead, it can be determined that the vehicle is in an intelligent following scenario. This is achieved by using the vehicle's built-in GPS module, radar module, cameras, and other sensors to obtain the distance between the vehicle ahead and the vehicle itself. Existing adaptive driving technology can maintain a safe following distance. When the vehicle's current following distance enters a preset range exceeding this safe distance, an energy recovery mode can be activated, achieving energy recovery while simultaneously reducing vehicle speed.

[0087] Furthermore, based on the configuration of the multi-gear transmission, the intensity of energy recovery can be changed by automatically downshifting. Depending on the current following distance and whether it falls within a preset following distance range, the transmission automatically switches between different gears to adjust the intensity of energy recovery accordingly. For example, if the transmission has four gears (first, second, third, and fourth), and the preset following distance range includes four zones: 800m–650m, 650m–500m, 500m–350m, and 350m–100m (100m being a safe distance), then the gears and zones correspond sequentially. When the current following distance falls within different zones, energy recovery is performed at different gears in the transmission, thus better utilizing the braking effect and efficiency of the energy recovery mode.

[0088] In energy recovery mode, if a fault is detected in the second motor 22, the vehicle should operate in front axle energy recovery mode. That is, rear axle and dual-axle energy recovery modes have higher priority than front axle energy recovery mode. When the second motor 40 fails, rear axle and dual-axle energy recovery modes cannot be implemented, and the vehicle can operate in front axle energy recovery mode to recover kinetic energy. The energy recovery mode settings fully consider situations where the vehicle's kinetic energy is lost, maximizing energy recovery during vehicle braking or coasting.

[0089] In summary, the off-road control method for a multi-mode hybrid vehicle in this embodiment, based on the configuration condition that the front axle wheels 11 and the rear axle wheels 12 of the vehicle can be driven separately, adopts a two-wheel drive mode (front-wheel drive or rear-wheel drive) during normal driving, and switches to a four-wheel drive mode in real time and accurately when rapid acceleration or getting out of trouble is required. By judging the difference in wheel speed between the front axle wheels 11 and the rear axle wheels 12 before switching, the actual driving torque demand of the front axle wheels 11 and the rear axle wheels 12 can be determined, thereby determining the necessity, accuracy, and effectiveness of the four-wheel drive mode switching, which can improve the overall driving efficiency of the hybrid vehicle.

[0090] Meanwhile, in the aforementioned off-road control method, based on the configuration of the engine 20, the first motor 21, and the second motor 22, different operating modes such as front-wheel drive, rear-wheel drive, four-wheel drive, pure electric, and hybrid can be configured for the vehicle through the coordinated driving of different operating states of the three drive components, in order to cope with different operating conditions and driving requirements of the vehicle. By detecting and acquiring the vehicle's working parameters in real time, the appropriate operating mode for the vehicle can be determined, thereby controlling the vehicle to operate in the appropriate operating mode, which is conducive to improving the overall driving efficiency of hybrid vehicles. Moreover, the overall control logic of this off-road control method is simple and efficient, avoiding the drawbacks of existing hybrid vehicle shift control strategies such as cumbersome shifting and inefficient frequent mode switching, and has good adaptability and economy.

[0091] Example 2

[0092] This embodiment relates to a vehicle that is driven by a hybrid system, and the hybrid system adopts the off-road control method for multi-mode hybrid vehicles provided in Embodiment 1.

[0093] The hybrid system in this embodiment is controlled based on the off-road control method of Embodiment 1, and its general configuration can be set with reference to the situation described in Embodiment 1.

[0094] Specifically, refer to Figure 1 As shown, based on the configuration of engine 20, first motor 21 and second motor 22, the first motor 21 is connected to engine 20 through a transmission, and both the first motor 21 and engine 20 are connected to the front axle wheels 11 through a transmission device. Through the transmission device, the engine 20 can drive the front axle wheels 11, while the first motor 21 can operate under the drive of engine 20 to generate electricity or output power to drive the front axle wheels 11. The second motor 22 can directly drive the rear axle wheels 12, thus providing a hybrid architecture that can match multiple operating modes, enabling the vehicle to match multiple different power drive operating modes, providing a good hardware foundation for enriching the vehicle's drive operating modes and improving the vehicle's overall drive efficiency.

[0095] Meanwhile, the aforementioned transmission device includes parallel-arranged input and output shafts, as well as a shifting mechanism. The engine 20 is connected to the input shaft via a disconnect mechanism, the first motor 21 is driven by the input shaft, and the output shaft is driven by the front axle wheels 11. Multiple shift gear sets are arranged between the input and output shafts, and the shifting mechanism can select a specific shift gear set to form the transmission connection between the input and output shafts. By arranging multiple shift gear sets in the input and output shafts of the transmission device, and by having both the engine 20 and the first motor 21 drive the front axle wheels 11 through gear shifting, multi-gear control of the vehicle can be achieved, which is beneficial for improving the vehicle's power and operating economy.

[0096] Specifically, the input shaft of this embodiment includes a second input shaft 302 and a first input shaft 301 sleeved on the second input shaft 302, while the output shaft includes a main output shaft 311 and a secondary output shaft 312 arranged in parallel. The shift gear set specifically includes a first gear set 321, a second gear set 322, a third gear set 323, and a fourth gear set 324 with progressively smaller transmission ratios, to respectively realize the power transmission of the four gears of the transmission device: first gear (G1), second gear (G2), third gear (G3), and fourth gear (G4). The engine 20 is connected to one end of the input shaft through a first clutch 411, and the first motor 21 is connected to the other end of the input shaft through a motor transmission gear set 33. In this configuration, the first gear set 321 and the second gear set 322 are arranged adjacent to each other. The two driving gears in each set are fixed to the first input shaft 301, and the two driven gears in each set are mounted on the main output shaft 311. A first synchronizer 421 is positioned between the two driven gears. Similarly, the second gear set 322 and the fourth gear set 324 are arranged adjacent to each other. The two driving gears in each set are fixed to the second input shaft 302, and the two driven gears in each set are mounted on the main output shaft 311. A second synchronizer 422 is positioned between the two driven gears. The first synchronizer 421, the second synchronizer 422, and the first clutch 411 work together to achieve the function of the shifting mechanism. The first synchronizer 421 and the second synchronizer 422 can be driven by a shifting motor to perform shifting actions.

[0097] A differential 24 is mounted on the drive shaft of the front axle wheel 11. A forward gear output gear 327 is provided at the end of the main output shaft 311. The forward gear output gear 327 meshes with the front axle gear 328 on the differential 24 to output power to the front axle wheel 11. At the same time, a reverse gear output gear 326 and a parking gear 329 are fixedly mounted on the auxiliary output shaft 312, and a reverse transmission gear 325 is mounted thereon, which is connected to the driven gear in the first gear set 321. A second clutch 412 is also provided on the auxiliary output shaft 312, which can engage or disengage the reverse transmission gear 325. By operating the second clutch 412, the reverse gear (R) control of the vehicle can be realized. By locking the parking gear 329, the parking (P) function of the vehicle can be realized.

[0098] In this embodiment, in addition to the following, the first motor 21 and the input shaft are connected by: Figure 1In addition to the transmission form of the motor drive gear set 33 shown, the motor shaft of the first motor 21 can also be directly connected to the input shaft. This eliminates the need for a separate transmission assembly between the motor shaft and the input shaft, reducing the number of parts and the complexity of the device. When the motor shaft and the input shaft are directly connected, they can be detachably connected, for example, by splines, facilitating subsequent disassembly. Alternatively, the motor shaft and the input shaft of the first motor 21 can be constructed as a single unit, i.e., the motor shaft and the input shaft are the same shaft. This reduces the number of parts and eliminates the need for disassembly structures such as splines.

[0099] Based on the aforementioned hybrid system and its off-road control method, the driving conditions and operating status of the vehicle can be intelligently identified according to the vehicle's working parameters, and the hybrid system can be controlled to adopt the most suitable operating mode, thereby effectively increasing the driving efficiency and fuel economy of the entire vehicle.

[0100] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An off-road control method for a multi-mode hybrid vehicle, characterized in that: The multi-mode hybrid vehicle has an engine (20) and a first motor (21) for driving the front axle wheels (11), a second motor (22) for driving the rear axle wheels (12), and a battery (25) connecting the first motor (21) and the second motor (22). The control method includes: By matching the different operating states of the engine (20), the first motor (21) and the second motor (22), the vehicle is configured with multiple operating modes, including a two-wheel drive mode in which only the front axle wheel (11) or the rear axle wheel (12) is driven, and a four-wheel drive mode in which both the front axle wheel (11) and the rear axle wheel (12) are driven. The operating modes also include a pure electric mode in which the vehicle is driven by the first motor (21) and / or the second motor (22), an engine mode in which the engine (20) provides power output, and a hybrid mode in which the engine (20) works in conjunction with the first motor (21) or the second motor (22) to drive the vehicle. The pure electric mode includes an electric front-wheel drive mode and an electric rear-wheel drive mode corresponding to the two-wheel drive mode, and an electric four-wheel drive mode corresponding to the four-wheel drive mode. The hybrid mode includes a hybrid front-wheel drive mode corresponding to the two-wheel drive mode, and a hybrid four-wheel drive mode corresponding to the four-wheel drive mode. The system acquires real-time information on the vehicle's accelerator pedal opening, current operating conditions, and wheel speeds of both the active and driven wheels. When the following off-road preset conditions are met, the system switches from two-wheel drive mode to four-wheel drive mode: The rate of change of the accelerator pedal opening rises above a set threshold and remains there for a set time, or the working condition is determined to be an off-road condition. The difference between the rotational speed of the driving wheel and the rotational speed of the driven wheel, or the difference between the rotational speeds of the left and right wheels of the two driving wheels, is greater than or equal to a set rotational speed difference. Furthermore, when the off-road preset conditions are met, the current vehicle speed is obtained. When the vehicle speed is higher than the preset speed value, the system switches to the hybrid four-wheel drive mode, and when the vehicle speed is lower than the preset speed value, the system switches to the electric four-wheel drive mode.

2. The off-road control method for a multi-mode hybrid vehicle according to claim 1, characterized in that: The control method further includes: Obtain the battery power of the battery (25) and preset a first power value and a second power value in order from high to low; when the battery power is above the first power value, execute the pure electric mode; when the battery power is below the second power value, execute the engine mode; when the battery power is between the first power value and the second power value, execute the hybrid mode.

3. The off-road control method for a multi-mode hybrid vehicle according to claim 2, characterized in that: The engine modes include an engine direct drive mode in which the engine (20) drives the front axle wheels (11) through a transmission device, a series mode in which the engine (20) drives the first motor (21) to generate electricity and the second motor (22) drives the rear axle wheels (12), and an idle power generation mode in which the engine (20) drives the first motor (21) to generate electricity. The control method further includes: The vehicle speed is obtained. In the engine mode, when the vehicle speed of a moving vehicle is greater than the set speed, the engine direct drive mode is executed; when the speed is less than or equal to the set speed, the series mode is executed. When the vehicle is idling, the idle power generation mode is executed.

4. The off-road control method for a multi-mode hybrid vehicle according to claim 1, characterized in that: The operating mode includes a launch start mode, in which the engine (20) and the first motor (21) jointly drive the front axle wheels (11), and the second motor (22) drives the rear axle wheels (12); the control method further includes: The accelerator pedal opening is obtained, and when the accelerator pedal opening reaches the set opening value, the launch start mode is executed.

5. The off-road control method for a multi-mode hybrid vehicle according to any one of claims 1 to 4, characterized in that: The operating mode includes an energy recovery mode in which the first motor (21) is driven by the front axle wheel (11) and / or the second motor (22) is driven by the rear axle wheel (12) to generate electricity; The control method further includes: Determine whether the vehicle is in a braking or coasting state, and whether the described operating scenario is an intelligent following scenario; The vehicle executes the energy recovery mode when any of the following preset conditions are met: The vehicle is in a braking or coasting state; The vehicle is in a smart following scenario, and the current following distance is within the preset following distance range.

6. The off-road control method for a multi-mode hybrid vehicle according to claim 5, characterized in that: The energy recovery modes include a front axle energy recovery mode in which the first motor (21) is driven by the front axle wheel (11) to generate electricity, a rear axle energy recovery mode in which the second motor (22) is driven by the rear axle wheel (12) to generate electricity, and a dual axle energy recovery mode in which the first motor (21) and the second motor (22) are driven by the front axle wheel (11) and the rear axle wheel (12) respectively to generate electricity.

7. The off-road control method for a multi-mode hybrid vehicle according to claim 6, characterized in that, Also includes: Under braking conditions, obtain the opening degree of the brake pedal; If the brake pedal opening is less than or equal to the first set opening value, control the vehicle to operate in rear axle energy recovery mode; If the brake pedal opening is greater than the second set opening value, the vehicle is controlled to operate in dual-axle energy recovery mode; the second set opening value is greater than the first set opening value.

8. A vehicle, said vehicle being driven by a hybrid system, characterized in that: The hybrid system employs the off-road control method for a multi-mode hybrid vehicle as described in any one of claims 1 to 7.

9. The vehicle according to claim 8, characterized in that: The first motor (21) is connected to the engine (20) in a transmission, and both the first motor (21) and the engine (20) are connected to the front axle wheel (11) through a transmission device. The transmission device includes an input shaft and an output shaft arranged in parallel, and a shifting mechanism; the engine (20) is connected to the input shaft through a cutting mechanism, the first motor (21) is connected to the input shaft in a transmission connection, the output shaft is connected to the front axle wheel (11) in a transmission connection, and multiple shifting gear sets are provided between the input shaft and the output shaft. The shifting mechanism can select a certain shifting gear set to form a transmission connection between the input shaft and the output shaft.

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