Mode switching method, vehicle and storage medium

Abstract

The invention provides a mode switching method, a vehicle and a storage medium, the method is applied to the technical field of hybrid power control, and the method comprises the steps that under the condition that a control instruction for switching the driving mode of the vehicle from a series mode to a direct drive mode is received, the direct drive mode of the vehicle is switched; the discharging power of a power battery of the vehicle, the whole vehicle driving power of the vehicle and the generating power of a target motor of the vehicle are determined, a target interval where the whole vehicle driving power is located is determined based on the discharging power of the power battery, the whole vehicle driving power and the generating power of the target motor, and a target torque reduction gradient corresponding to the target interval is determined; and then based on the target torque reduction gradient, the actual torque of the engine is controlled to be reduced to the target torque, and under the condition that the actual torque of the engine is equal to the target torque, the clutch is controlled to be in an open state, so that the driving mode of the vehicle is switched from the series mode to the direct drive mode. According to the method, the torque can be reduced gently, and power interruption caused by the fact that the engine torque is directly reduced to zero is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hybrid control, and more particularly, to a mode switching method, a vehicle and a storage medium in the technical field of hybrid control. BACKGROUND

[0002] With the transformation of the automobile industry to "low carbonization" and "electrification", hybrid vehicles have gained popularity due to their dual advantages of fuel economy and endurance. Due to the characteristics of fast torque response speed, high control precision (millisecond level torque adjustment) and smooth output without jerk, the motor is usually used to adjust the speed and torque of the input shaft of the gearbox during mode switching in hybrid vehicles.

[0003] However, in the "rigid connection of motor and gearbox input shaft" architecture adopted by some hybrid vehicles, since the motor and the gearbox input shaft are directly rigidly connected without a buffer mechanism, a short-term power interruption occurs during mode switching, resulting in poor driving experience. SUMMARY

[0004] The present application provides a mode switching method, a vehicle and a storage medium, which can realize smooth torque reduction and avoid power interruption caused by direct reduction of engine torque to zero.

[0005] In a first aspect, a mode switching method is provided, which includes: in the case of receiving a control instruction for switching the driving mode of a vehicle from a series mode to a direct drive mode, determining the discharge power of a power battery of the vehicle, the vehicle driving power and the power generation power of a target motor of the vehicle; based on the discharge power of the power battery, the vehicle driving power and the power generation power of the target motor, determining a target interval in which the vehicle driving power is located, and determining a target torque reduction gradient corresponding to the target interval; based on the target torque reduction gradient, controlling the actual torque of the engine to reduce to a target torque; in the case that the actual torque of the engine is equal to the target torque, controlling the clutch to be in an open state, so as to switch the driving mode of the vehicle from the series mode to the direct drive mode.

[0006] In the technical solution, when a control instruction for switching the driving mode of the vehicle from the series mode to the direct drive mode is received, the discharge power of the power battery of the vehicle, the vehicle driving power and the power generation of the target motor are calculated, the discharge power of the power battery, the vehicle driving power and the power generation of the target motor are accurately quantified, and data basis is provided for subsequent determination of the torque reduction gradient. Based on the discharge power of the power battery, the vehicle driving power and the power generation of the target motor, the target interval of the vehicle driving power is determined, and the target torque reduction gradient corresponding to the target interval is determined, so that the power demand under different working conditions can be accurately matched, the torque reduction gradient under different working conditions can be determined, and the torque reduction process can be ensured to be consistent with the actual driving scene. Then, based on the target torque reduction gradient, the actual torque of the engine is controlled to be reduced, so that the torque can be reduced smoothly, thereby avoiding the power interruption caused by the direct reduction of the engine torque to zero. And when the actual torque of the engine is reduced to equal the target torque, the clutch is controlled to be opened, so that the impact on mechanical components can be reduced, and the smoothness of the vehicle during the switching from the series mode to the direct drive mode can be ensured.

[0007] In combination with the first aspect, in some implementations of the first aspect, based on the discharge power of the power battery, the vehicle driving power and the power generation of the target motor, the target interval of the vehicle driving power is determined, and the target torque reduction gradient corresponding to the target interval is determined, including: when the vehicle driving power is less than or equal to the discharge power of the power battery, the target interval is determined to be a first interval, and a first torque reduction gradient corresponding to the first interval is determined as the target torque reduction gradient; when the vehicle driving power is greater than the discharge power of the power battery and less than or equal to the sum of the discharge power of the power battery and the power generation of the target motor, the target interval is determined to be a second interval, and a second torque reduction gradient corresponding to the second interval is determined as the target torque reduction gradient; wherein the first torque reduction gradient is greater than the second torque reduction gradient.

[0008] In the technical solution, the target interval of the vehicle driving power is determined, and the target torque reduction gradient corresponding to the target interval is determined, so that the power demand in different working conditions can be accurately matched, and the torque reduction gradient in different working conditions can be determined. In the case that the vehicle driving power is less than or equal to the discharge power of the power battery, it is determined that the vehicle driving power is in the first interval with lower power demand, and a larger first torque reduction gradient is determined as the target torque reduction gradient, so that the torque can be quickly reduced in the low power demand, and even if the torque is quickly reduced, the smoothness of the vehicle will not be greatly affected, and subsequent rapid mode switching can be facilitated, and power interruption can be avoided. In the case that the vehicle driving power is greater than the discharge power of the power battery and less than or equal to the sum of the discharge power of the power battery and the power generation power of the target motor, it is determined that the vehicle driving power is in the second interval with higher power demand, and a smaller second torque reduction gradient is determined as the target torque reduction gradient, so that the torque can be slowly reduced in the high power demand, and the continuity of the power is ensured, so that the power interruption caused by the direct reduction of the engine torque to zero can be avoided.

[0009] In combination with the first aspect and the above implementation manners, in some implementation manners of the first aspect, the target torque reduction gradient is determined by: obtaining an original air path torque request value of the engine and a current opening degree of an accelerator pedal of the vehicle; calculating a current power difference value between the vehicle driving power and the discharge power of the power battery; and determining the target torque reduction gradient based on the current power difference value, the original air path torque request value and the current opening degree of the accelerator pedal.

[0010] In the technical solution, the current power difference value between the vehicle driving power and the discharge power of the power battery is calculated, so that it can be determined whether the power battery can currently meet the vehicle driving demand, thereby determining the demand corresponding to the current scenario, and the original air path torque request value and the current opening degree of the accelerator pedal can be combined to determine the target torque reduction gradient together, so that the fine control of the target torque reduction gradient based on the demand in the current scenario is realized, and the reliability of the torque reduction control is improved.

[0011] In some implementation forms of the first aspect, in combination with the above implementation forms, the target torque reduction gradient is determined based on the current power difference, the original air path torque request value and the current opening degree of the accelerator pedal, including: determining a basic torque reduction gradient corresponding to the current power difference and the original air path torque request value based on a first corresponding relationship corresponding to the target interval, wherein the first corresponding relationship is a corresponding relationship between the two parameters of the power difference and the air path torque request value and the basic torque reduction gradient; the power difference is a difference between the driving power of the vehicle and the discharge power of the power battery; determining a first target correction coefficient corresponding to the current power difference and the current opening degree of the accelerator pedal based on a second corresponding relationship corresponding to the target interval, wherein the second corresponding relationship is a corresponding relationship between the two parameters of the power difference and the opening degree of the accelerator pedal and the correction coefficient; and determining the target torque reduction gradient based on the basic torque reduction gradient and the first target correction coefficient.

[0012] In the above technical solution, when determining the basic torque reduction gradient, the power difference and the original air path torque request value are considered. The power difference can reflect the size relationship between the driving power of the vehicle and the discharge power of the power battery, and thus can reflect the over-discharge situation of the power battery. The greater the power difference, the greater the risk of over-discharge of the power battery. The determined basic torque reduction gradient can ensure that the over-discharge situation of the power battery is avoided. The original air path torque request value can represent the high-load working state of the engine, so that the determined basic torque reduction gradient avoids high load of the engine. The opening degree of the accelerator pedal can represent the power demand. The first target correction coefficient is determined based on the opening degree of the accelerator pedal and the power difference to correct the basic torque reduction gradient, so that the target torque reduction gradient can take into account the current power demand of the vehicle, and the accuracy of the torque reduction control is further improved.

[0013] In some implementation forms of the first aspect, in combination with the above implementation forms, the target torque reduction gradient includes a target fire path torque reduction gradient and a target air path torque reduction gradient, and the target torque reduction gradient is determined based on the basic torque reduction gradient and the first target correction coefficient, including: multiplying the basic torque reduction gradient and the first target correction coefficient to obtain the target fire path torque reduction gradient; correcting the target fire path torque reduction gradient based on a second target correction coefficient to obtain the target air path torque reduction gradient; wherein the target fire path torque reduction gradient is greater than the target air path torque reduction gradient; and the second target correction coefficient is used to control the absolute value of the torque difference between the reduced fire path torque and the reduced air path torque to be less than or equal to a preset difference value.

[0014] In the technical solution, the target fire path torque reduction gradient and the target air path torque reduction gradient are determined, so that the engine fire path torque and the engine air path torque can be controlled to reduce torque, the second target correction coefficient can make the torque difference between the reduced fire path torque and the reduced air path torque less than or equal to the preset difference, and the problem that the fuel consumption is large due to the separation of the air path and the fire path during the torque reduction process is avoided, and the economy of the vehicle during the gear shifting process is improved.

[0015] In combination with the first aspect and the above implementation manners, in some implementation manners of the first aspect, the target torque includes a target fire path torque and a target air path torque, and the target torque is determined by: determining an original air path torque request value based on the driver demand torque, the target front-rear axle torque distribution ratio, and the actual torque of the target electric machine; determining the target fire path torque based on the original air path torque request value, the gear shifting intervention torque, and the engine fire path speed control torque; and determining the target air path torque based on the original air path torque request value, the engine air path torque reservation, the engine air path speed control torque reservation, and the target fire path torque.

[0016] In the technical solution, the target fire path torque reduction gradient and the target air path torque reduction gradient are determined, so that the engine fire path torque and the engine air path torque can be controlled to reduce torque, the second target correction coefficient can make the torque difference between the reduced fire path torque and the reduced air path torque less than or equal to the preset difference, and the problem that the fuel consumption is large due to the separation of the air path and the fire path during the torque reduction process is avoided, and the economy of the vehicle during the gear shifting process is improved.

[0017] In combination with the first aspect and the above implementation manners, in some implementation manners of the first aspect, the target torque includes a target fire path torque and a target air path torque, and the target torque is determined by: determining an original air path torque request value based on the driver demand torque, the target front-rear axle torque distribution ratio, and the actual torque of the target electric machine; determining the target fire path torque based on the original air path torque request value, the gear shifting intervention torque, and the engine fire path speed control torque; and determining the target air path torque based on the original air path torque request value, the engine air path torque reservation, the engine air path speed control torque reservation, and the target fire path torque.

[0018] With reference to the first aspect and the foregoing implementation manners, in some implementation manners of the first aspect, the method further includes: if the fire path torque of the engine controlled according to the target fire path torque reduction gradient does not reach the target fire path torque, determining a target number of cylinders to be deactivated in the engine based on the target fire path torque and a target torque range of a single cylinder; wherein the target torque range of the single cylinder is determined based on a target adjustment range of the ignition angle; and deactivating the cylinders corresponding to the target number of cylinders to be deactivated in the engine to reduce the fire path torque to the target fire path torque.

[0019] The foregoing technical solution can accurately determine the target number of cylinders to be deactivated in the engine based on the target fire path torque and the target torque range of a single cylinder in a case where the fire path torque cannot be reduced to the target fire path torque through the target fire path torque reduction gradient, ensure that the single-cylinder torque of the remaining cylinders after deactivation is still in the compliance range, and avoid unstable combustion caused by excessive torque reduction. Then, the cylinders corresponding to the target number of cylinders to be deactivated in the engine are deactivated to directly reduce the torque output of the engine by reducing the number of cylinders that effectively work, and finally the fire path torque is accurately reduced to the target fire path torque.

[0020] With reference to the first aspect and the foregoing implementation manners, in some implementation manners of the first aspect, the control of the clutch in the open state to switch the driving mode of the vehicle from the series mode to the direct drive mode includes: controlling the clutch in the open state and switching the gear of the transmission of the vehicle to a target gear corresponding to the direct drive mode when the clutch is in the open state; controlling the clutch in the closed state in a case where the rotational speed difference between the two ends of the clutch is less than or equal to a preset rotational speed difference; determining a target torque increase gradient in a case where the clutch is in the closed state; and controlling the actual torque of the engine to increase based on the target torque increase gradient to switch the driving mode of the vehicle from the series mode to the direct drive mode.

[0021] The foregoing technical solution can switch the gear of the transmission to the target gear corresponding to the direct drive mode after the clutch is in the open state, establish a mechanical transmission basis in the direct drive mode in advance, and prepare for subsequent power path switching, thereby facilitating accurate control of the vehicle in the direct drive mode. In addition, the clutch is controlled in the closed state in a case where the rotational speed difference between the two ends of the clutch is less than or equal to the preset rotational speed difference, the rotational speeds at the two ends of the clutch are synchronized through control, mechanical impact during engagement is eliminated, and it is ensured that the clutch can be safely and smoothly closed, thereby avoiding gear shifting jerk or component wear caused by excessive rotational speed difference. In a case where the clutch is in the closed state, the actual torque of the engine is controlled to increase based on the target torque increase gradient, the engine power is smoothly transmitted to the wheels through the engaged clutch and the engaged gear of the transmission, the driving mode of the vehicle is switched from the series mode to the direct drive mode, and power interruption during the switching process is avoided.

[0022] In conjunction with the first aspect and the above-mentioned implementation methods, in some implementation methods of the first aspect, determining the target torque increase gradient includes: acquiring the current engine speed, the current engine torque, the clutch pressure, the accelerator pedal opening, and the current vehicle speed; determining the basic torque increase gradient based on the current engine speed and the current engine torque; determining the first correction coefficient based on the current engine torque and the clutch pressure; determining the second correction coefficient based on the accelerator pedal opening and the current vehicle speed; and determining the target torque increase gradient based on the basic torque increase gradient, the first correction coefficient, and the second correction coefficient.

[0023] The above technical solution, after determining the basic torque increase gradient based on the current engine speed and torque, further dynamically corrects the basic torque increase gradient by combining the current engine torque, clutch pressure, accelerator pedal opening, and current vehicle speed, ultimately obtaining the target torque increase gradient. By first determining the basic torque increase gradient and then correcting it based on multi-dimensional factors, various factors affecting the torque increase process can be fully considered. This allows for matching different target torque increase gradients to different operating conditions, and by optimizing multiple parameters, torque fluctuations caused by a single factor are avoided, thus ensuring the smoothness of the torque increase process under various operating conditions.

[0024] Secondly, a mode switching device is provided, comprising: a first determining module, configured to determine the discharge power of the vehicle's power battery, the vehicle's overall drive power, and the power generation power of the vehicle's target motor upon receiving a control command to switch the vehicle's drive mode from a series mode to a direct drive mode; a second determining module, configured to determine a target range of the vehicle's drive power based on the power battery's discharge power, the vehicle's overall drive power, and the target motor's power generation power, and to determine a target torque reduction gradient corresponding to the target range; a first control module, configured to control the engine's actual torque to decrease to the target torque based on the target torque reduction gradient; and a second control module, configured to control the clutch to be in an open state when the engine's actual torque equals the target torque, so as to switch the vehicle's drive mode from a series mode to a direct drive mode.

[0025] In conjunction with the second aspect, in some implementations of the second aspect, the second determining module is specifically used for: determining a target interval as a first interval when the vehicle driving power is less than or equal to the discharge power of the power battery, and determining the first torque reduction gradient corresponding to the first interval as the target torque reduction gradient; determining a target interval as a second interval when the vehicle driving power is greater than the discharge power of the power battery and less than or equal to the sum of the discharge power of the power battery and the power generation power of the target motor, and determining the second torque reduction gradient corresponding to the second interval as the target torque reduction gradient; wherein, the first torque reduction gradient is greater than the second torque reduction gradient.

[0026] In some implementations of the second aspect and the above implementations, the apparatus further includes a target torque reduction gradient determination module configured to: obtain an original air path torque request value of the engine and a current opening degree of the accelerator pedal of the vehicle; calculate a current power difference between the vehicle driving power and the discharging power of the power battery; determine the target torque reduction gradient based on the current power difference, the original air path torque request value, and the current opening degree of the accelerator pedal.

[0027] In some implementations of the second aspect and the above implementations, the target torque reduction gradient determination module is further configured to: determine a basic torque reduction gradient corresponding to the current power difference and the original air path torque request value based on a first corresponding relationship corresponding to the target interval; the first corresponding relationship is a corresponding relationship between the basic torque reduction gradient and two parameters of the power difference and the air path torque request value; the power difference is a difference between the vehicle driving power and the discharging power of the power battery; determine a first target correction coefficient corresponding to the current power difference and the current opening degree of the accelerator pedal based on a second corresponding relationship corresponding to the target interval; the second corresponding relationship is a corresponding relationship between the correction coefficient and two parameters of the power difference and the opening degree of the accelerator pedal; and determine the target torque reduction gradient based on the basic torque reduction gradient and the first target correction coefficient.

[0028] In some implementations of the second aspect and the above implementations, the target torque reduction gradient includes a target fire path torque reduction gradient and a target air path torque reduction gradient, and the target torque reduction gradient determination module is further configured to: multiply the basic torque reduction gradient and the first target correction coefficient to obtain the target fire path torque reduction gradient; correct the target fire path torque reduction gradient based on a second target correction coefficient to obtain the target air path torque reduction gradient; the target fire path torque reduction gradient is greater than the target air path torque reduction gradient; and the second target correction coefficient is used to control an absolute value of a torque difference between the reduced fire path torque and the reduced air path torque to be less than or equal to a preset difference value.

[0029] In some implementations of the second aspect and the above implementations, the target torque includes a target fire path torque and a target air path torque, and the apparatus further includes a target torque determination module configured to: determine the original air path torque request value based on the driver demand torque, the target front-rear axle torque distribution ratio, and the actual torque of the target motor; determine the target fire path torque based on the original air path torque request value, the shift intervention torque, and the engine fire path speed control torque; and determine the target air path torque based on the original air path torque request value, the engine air path torque reservation, the engine air path speed control torque reservation, and the target fire path torque.

[0030] With reference to the second aspect and the foregoing implementation manners, in some implementations of the second aspect, the target torque reduction gradient includes a target fire path torque reduction gradient and a target air path torque reduction gradient, and the target torque includes a target fire path torque and a target air path torque, and the first control module is specifically configured to: control the fire path torque of the engine to decrease to the target fire path torque according to the target fire path torque reduction gradient; and control the air path torque of the engine to decrease to the target air path torque according to the target air path torque reduction gradient in the process of controlling the fire path torque of the engine to decrease according to the target fire path torque reduction gradient, so that the absolute value of the torque difference between the decreased fire path torque and the decreased air path torque is less than or equal to the preset difference, and the ignition angle of the engine is ensured to be within the target adjustment range.

[0031] With reference to the second aspect and the foregoing implementation manners, in some implementations of the second aspect, the apparatus further includes a cylinder cut-off control module, which is specifically configured to: if the fire path torque after the fire path torque of the engine is controlled to decrease according to the target fire path torque reduction gradient does not reach the target fire path torque, determine a target number of cylinders to be cut off in the engine based on the target fire path torque and a target torque range of a single cylinder, wherein the target torque range of the single cylinder is determined based on the target adjustment range of the ignition angle; and perform cylinder cut-off processing on the cylinders corresponding to the target number of cylinders to be cut off in the engine, so that the fire path torque is decreased to the target fire path torque.

[0032] With reference to the second aspect and the foregoing implementation manners, in some implementations of the second aspect, the second control module is specifically configured to: control the clutch to be in an open state, and control the gear of the transmission of the vehicle to switch to a target gear corresponding to the direct drive mode when the clutch is in the open state; control the clutch to be in a closed state when the speed difference between the two ends of the clutch is less than or equal to a preset speed difference; and determine the target torque increase gradient when the clutch is in the closed state, and control the actual torque of the engine to increase based on the target torque increase gradient, so that the driving mode of the vehicle is switched from the series mode to the direct drive mode.

[0033] With reference to the second aspect and the foregoing implementation manners, in some implementations of the second aspect, the second control module includes a determination unit, which is specifically configured to: obtain the current speed of the engine, the current torque of the engine, the pressure of the clutch, the accelerator pedal opening degree of the vehicle, and the current speed of the vehicle; determine a basic torque increase gradient based on the current speed of the engine and the current torque of the engine; determine a first correction coefficient based on the current torque of the engine and the pressure of the clutch; determine a second correction coefficient based on the accelerator pedal opening degree and the current speed of the vehicle; and determine the target torque increase gradient based on the basic torque increase gradient, the first correction coefficient, and the second correction coefficient.

[0034] In a third aspect, a vehicle is provided, comprising a memory and a processor. The memory is configured to store executable program code, and the processor is configured to invoke and run the executable program code from the memory, so that the vehicle performs the mode switching method in the first aspect and any possible implementation of the first aspect.

[0035] In a fourth aspect, a computer program product is provided, comprising computer program code which, when run on a computer, causes the computer to perform the mode switching method in the first aspect and any possible implementation of the first aspect.

[0036] In a fifth aspect, a computer-readable storage medium is provided, storing computer program code which, when run on a computer, causes the computer to perform the mode switching method in the first aspect and any possible implementation of the first aspect. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 is a schematic diagram of an architecture of a hybrid vehicle provided by an embodiment of the present application;

[0038] Figure 2 is a schematic flowchart of a mode switching method provided by an embodiment of the present application;

[0039] Figure 3 is a schematic diagram of a control process of switching from a series mode to a direct drive mode provided by an embodiment of the present application;

[0040] Figure 4 is a schematic diagram of a mode switching device provided by an embodiment of the present application;

[0041] Figure 5 is a schematic diagram of a vehicle provided by an embodiment of the present application. DETAILED DESCRIPTION

[0042] The technical solutions in the present application will be described in detail below with reference to the drawings. In the description of the embodiments of the present application, unless otherwise specified, " / " represents the meaning of or, for example, A / B can represent A or B: "and / or" in the text is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist together, and B exists alone, and in addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0043] Hereinafter, the terms "first", "second", "third", etc. are used only for descriptive purposes and should not be construed as implying or suggesting relative importance or an indicated number of technical features. Thus, features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features.

[0044] With the transformation of the automobile industry towards "low carbonization" and "electrification", hybrid vehicles have gained popularity due to their dual advantages of fuel economy and endurance. Due to the characteristics of fast torque response, high control precision (millisecond-level torque adjustment) and smooth output without jerk, the motor is usually used to adjust the speed and torque of the input end of the gearbox during mode switching in hybrid vehicles.

[0045] However, in the "motor and gearbox input shaft rigid connection" architecture adopted by some hybrid vehicles, due to the direct rigid connection between the motor and the gearbox input shaft without a buffer mechanism, a short-term power interruption may occur during mode switching, resulting in a poor driving experience.

[0046] Figure 1 is a schematic diagram of a hybrid vehicle architecture provided by an embodiment of the present application.

[0047] As shown in Figure 1 , the architecture corresponding to the hybrid vehicle 100 is an example of the "motor and gearbox input shaft rigid connection" architecture.

[0048] The hybrid vehicle 100 includes an engine 101, a clutch 102, a front motor 103, a gearbox 104, a rear motor 105, a power battery 106, a left front wheel 1071, a right front wheel 1072, a left rear wheel 1081, and a right rear wheel 1082.

[0049] The engine 101 is one of the power sources of the vehicle, which generates power by burning fuel (such as gasoline or diesel). The power generated by the engine is transmitted to the clutch 102 and the gearbox 104 through the crankshaft, and finally drives the front wheels of the hybrid vehicle 100.

[0050] The clutch 102 is used to disconnect or connect the mechanical connection between the engine 101 and the gearbox 104. The clutch 102 includes two states of open state and closed state. When the clutch 102 is in the open state, the engine 101 and the gearbox 104 are disconnected, and at this time even if the engine 101 is running, the power generated will not be transmitted to the gearbox 104. When the clutch 102 is in the closed state, the engine 101 and the gearbox 104 are mechanically connected, and at this time the power generated by the engine 101 can be transmitted to the gearbox 104.

[0051] The front motor 103, also known as P2 motor, can be rigidly connected with the input shaft of the gearbox 104. The front motor 103 is used to drive the front wheels of the vehicle through the gearbox 104. The front motor 103 can also work as a generator.

[0052] As an embodiment, when the front motor 103 works as a generator, the clutch 102 is in a closed state, the engine 101 transmits power to the front motor 103 through the clutch 102 and the gearbox 104, and the front motor 103 generates electricity.

[0053] The gearbox 104 is arranged in the front axle of the vehicle, and can also be referred to as a front axle gearbox. The gearbox 104 is used to change the speed and torque output by the engine 101 to adapt to different driving conditions and ensure efficient operation of the vehicle under different speed and load conditions.

[0054] The rear motor 105, also known as P4 motor, transmits power to the rear wheels of the vehicle when it operates to drive the vehicle.

[0055] The power battery 106, also known as high-voltage battery, is used to supply power to the front motor 103 and the rear motor 105 to make the front motor 103 and the rear motor 105 output torque to drive the vehicle.

[0056] When the engine 101 drives the front motor 103 to generate electricity, the electricity generated by the front motor 103 can also charge the power battery 106; or the electricity generated by the front motor 103 can be directly provided to the rear motor 105 to drive the vehicle.

[0057] It can be understood that the above Figure 1 As an example, the above "rigid connection between the motor and the input shaft of the gearbox" architecture can also be other architectures, and the specific design of the architecture is not limited in the embodiments of the application.

[0058] Further, if the front motor 103 is rigidly connected with the input shaft of the gearbox 104, it means that both are equivalent to the same rotating part, and as long as one of them rotates, the other must rotate at the same speed; on the contrary, if the speed of one part is to be controlled, the speed of the other part must be controlled synchronously. And since the gear shifting action of the gearbox 104 is usually realized by controlling the speed of the input shaft of the gearbox, in the case of rigid connection between the front motor 103 and the input shaft of the gearbox 104, the front motor 103 has to bear the function of gear shifting of the gearbox.

[0059] Specifically, when shifting gears, a traditional fuel vehicle usually disconnects the clutch first (i.e., decouples the engine from the gearbox), allows the gearbox input shaft to freely decelerate or accelerate after losing power, and then switches gears (load-free gear shifting, avoiding gear tooth impact) to complete the gear shifting operation. However, in the hybrid vehicle 100 shown in Figure 1 In the hybrid vehicle 100 shown in FIG. 1, because the front motor 103 is rigidly connected to the input shaft of the gearbox 104, the input shaft of the gearbox 104 cannot freely rotate, and the input shaft speed must be actively controlled by the front motor 103 to match the "target gear corresponding gear speed" to complete the gear shifting operation.

[0060] Further, in the case of rigid connection between the front motor 103 and the input shaft of the gearbox 104, any force acting on the input shaft of the gearbox 104 (such as power transmitted by the engine through the clutch) will directly affect the front motor 103. Based on this, if a mode switching request is received, the engine 101 and the front motor 103 usually need to be decoupled, so that the engine and the motor are controlled independently, i.e., the clutch 102 is controlled to be opened.

[0061] The inventors of the present application have found through research that, in the case of rigid connection between the front motor and the input shaft of the gearbox, if a control instruction is received to switch the driving mode of the vehicle from series mode to direct drive mode, the clutch usually needs to be controlled to be opened, and controlling the clutch to be opened usually causes the power path of "engine-clutch-input shaft of gearbox" to be cut off, thereby causing the engine to be unable to drive the front motor to generate electricity, and the front motor can only rely on the power battery for power to drive the vehicle. Therefore, in the case where the clutch is in the open state, once the power battery is fed, the power of the front motor and the rear motor cannot be maintained, resulting in a problem of power interruption during mode switching.

[0062] To solve the above technical problems, the embodiments of the present application provide a mode switching method, and the execution subject of the method is a vehicle, specifically a controller in the vehicle. The method can determine a corresponding target torque reduction gradient according to a target interval of the driving power of the vehicle, and reduce the engine torque according to the target torque reduction gradient, so as to achieve a gentle reduction of the torque, thereby avoiding power interruption caused by direct reduction of the engine torque to zero.

[0063] Figure 2 FIG. 1 is a schematic flowchart of a mode switching method provided by an embodiment of the present application.

[0064] For example, as shown in FIG. 2, the method 200 includes: Figure 2

[0065] ​In step 201, in a case where a control instruction of switching a driving mode of the vehicle from a series mode to a direct drive mode is received, a discharge power of a power battery of the vehicle, a vehicle driving power of the vehicle, and a power generation of a target motor of the vehicle are determined.

[0066] In step 202, based on the discharge power of the power battery, the vehicle driving power, and the power generation of the target motor, a target interval in which the vehicle driving power is located is determined, and a target torque reduction gradient corresponding to the target interval is determined.

[0067] In step 203, based on the target torque reduction gradient, an actual torque of the engine is controlled to be reduced to a target torque.

[0068] In step 204, in a case where the actual torque of the engine is equal to the target torque, the clutch is controlled to be in an open state, so that the driving mode of the vehicle is switched from the series mode to the direct drive mode.

[0069] In the embodiment of the present application, in a case where a control instruction of switching a driving mode of the vehicle from a series mode to a direct drive mode is received, a discharge power of a power battery of the vehicle, a vehicle driving power of the vehicle, and a power generation of a target motor of the vehicle are calculated, so as to provide a data basis for subsequent determination of a torque reduction gradient by accurately quantifying the discharge power of the power battery, the vehicle driving power, and the power generation of the target motor. Based on the discharge power of the power battery, the vehicle driving power, and the power generation of the target motor, a target interval in which the vehicle driving power is located is determined, and a target torque reduction gradient corresponding to the target interval is determined, so as to accurately match power requirements in different working conditions, thereby determining torque reduction gradients in different working conditions, and ensuring that the torque reduction process is in line with actual driving scenarios. Then, based on the target torque reduction gradient, the actual torque of the engine is controlled to be reduced, so as to achieve a gentle reduction of the torque, thereby avoiding power interruption caused by a direct reduction of the engine torque to zero. Moreover, in a case where the actual torque of the engine is reduced to be equal to the target torque, the clutch is controlled to be opened, so as to reduce the impact on mechanical components and ensure the smoothness of the process of switching the vehicle from the series mode to the direct drive mode.

[0070] The specific implementation of each step in the embodiment shown in FIG. 1 will be described in detail as follows: Figure 2

[0071] ​In step 201, in series mode, the engine drives a motor mounted on the same axle to generate electricity, and a motor mounted on a different axle drives the wheels to move the vehicle. For example, the motor mounted on the same axle as the engine is a front-drive motor, and the motor mounted on a different axle is a rear-drive motor. In series mode, the engine runs, the front-drive motor generates electricity, and the electricity generated by the front-drive motor can charge the battery pack. The front-drive wheels are driven, and the rear-drive motor outputs power, driving the rear axle wheels to move the vehicle.

[0072] In direct drive mode, the engine drives the wheels directly through a mechanical transmission path, while the electric motor can either participate or not. When the motor is not engaged, the engine's speed and torque act directly on the wheels, similar to the drive system of a traditional gasoline-powered vehicle. When the electric motor is engaged, it can function as both a drive motor and a generator. Specifically, when the vehicle requires high torque output and the engine's torque output is insufficient, both the engine and the electric motor act as drive sources to propel the wheels; in this case, the electric motor functions as a drive motor. Conversely, when the vehicle's torque output requirement is low, the engine's torque can not only drive the wheels but also power the electric motor to generate electricity, charging the battery or supplying power to the vehicle's electrical systems; in this case, the electric motor functions as a generator.

[0073] Furthermore, in the aforementioned direct drive mode, the situation where the motor participates in the operation can also be called "parallel mode." In other words, parallel mode is a special type of direct drive mode.

[0074] For example, the control command to switch the vehicle's drive mode from series drive to direct drive can be initiated by the user via virtual buttons on the vehicle's infotainment screen or via voice command. This application does not limit the method of initiating the control command.

[0075] Furthermore, upon receiving the control command to switch the vehicle's drive mode from series mode to direct drive mode, in order to ensure the smoothness of the mode switching process under different driving conditions, the discharge power of the vehicle's power battery, the vehicle's total drive power, and the power generation power of the vehicle's target motor can be calculated. Based on the above parameters, the current driving condition can be determined, and different torque reduction strategies can be matched according to different driving conditions to achieve smooth mode switching.

[0076] The discharge power of the aforementioned power battery refers to the electrical power currently output by the power battery for driving, measured in kilowatts (kW).

[0077] For example, the discharge power of the aforementioned power battery can be calculated using the following formula:

[0078] PB = P L - P H - P R (1)

[0079] In the above formula (1), P B refers to the discharge power of the power battery (unit: KW); P L refers to the long-time discharge power of the power battery (unit: KW); P H refers to the consumption power of the high-voltage accessories in the vehicle (unit: KW); P R refers to the reserved vehicle driving power (unit: KW).

[0080] Specifically, the above P L can be calculated by the battery management system (BMS) in the vehicle based on the actual operating parameters of the battery; the above P H can be obtained by adding the real-time consumption power of each high-voltage accessory in the vehicle collected by the sensor; and the above P R can be determined by the controller of the vehicle according to the real-time vehicle state (such as vehicle speed, acceleration, battery capacity, remaining range, etc.).

[0081] The vehicle driving power refers to the total vehicle driving power currently required by the vehicle, which can also be referred to as "current driver vehicle driving power", and the unit is KW.

[0082] It can be understood that in the series mode, the vehicle is usually driven by the motor arranged in different axles from the engine. Based on this, if the motor arranged in different axles from the engine is P4 motor, the above vehicle driving power is mainly provided by the P4 motor.

[0083] Exemplarily, the above vehicle driving power can be calculated by the following formula:

[0084]

[0085] In the above formula (2), P D refers to the above vehicle driving power (unit: KW); T P4 refers to the requested torque value of the P4 motor (unit: Newton meter (NM)); and N P4P4 motor current speed (unit: rpm) ; η1 refers to the conversion efficiency between electric power and driving mechanical power in the vehicle (unit: %) ; "9550" refers to a unit conversion coefficient derived according to the physical relationship of power, torque and speed, used to ensure that the unit of the final output power is KW; "100" is related to the conversion efficiency η1, and the unit of η1 is "%", when the above formula (2) is only substituted with the corresponding value of η1 (for example, η1 is 80%, and in the formula (2), only the value "80" can be substituted), the "100" in the above formula can make the finally calculated vehicle driving power P D Still considering the conversion efficiency η1.

[0086] Specifically, the above T P4 Specifically, the vehicle controller can determine and issue a request torque value to the P4 motor according to the driver's demand (such as the accelerator pedal, target vehicle speed, etc.) ; the above N P4 Specifically, it can be measured in real time by a sensor in the P4 motor; the above η1 can be based on the request torque value T P4 and the current speed N P4 of the P4 motor.

[0087] For example, the current output torque T p4 of the P4 motor is 70NM, the current speed N P4 of the P4 motor of the vehicle is 3000rpm, and the conversion efficiency η1 is 80%, and the calculation can obtain the current vehicle driving power P D = ((70*3000) / 9550*80)*100 ≈ 27.49KW.

[0088] The above target motor refers to the motor in the vehicle as a generator in series mode, which can be the motor arranged in the same axle as the vehicle. For example, if the motor arranged in the same axle as the vehicle is P2 motor, the above target motor is P2 motor.

[0089] Taking the P2 motor as an example, the power generation power of the target motor refers to the current power generation power of the P2 motor, and the unit is KW.

[0090] For example, the power generation power of the above target motor can be calculated by the following formula (3) :

[0091]

[0092] In formula (3), P E refers to the power generation power of the above target motor (unit: KW) ; T P2 refers to the current actual torque value of the P2 motor (unit: NM) ; NP2 P2 motor current speed (unit: rpm); η2 refers to the efficiency of the P2 motor (unit: %); "9550" refers to a unit conversion coefficient derived from the physical relationship of power, torque, and speed, used to ensure that the unit of the final output power is KW; "100" is related to the motor efficiency η2, and the unit of η2 is "%"; when the above formula (3) is only substituted with the corresponding value of η2 (for example, η2 is 85%, and in formula (3), only the value "85" can be substituted), the multiplication of "100" in the above formula can make the finally calculated target motor power P E Still considering the motor efficiency η2.

[0093] Specifically, the above T P2 can be obtained by the torque sensor in the P2 motor; the above N P2 can be measured in real time by the speed sensor in the P2 motor; and the above η2 can be obtained from the pre-stored efficiency MAP table based on the actual torque value T P2 and the current speed N P2 of the P2 motor.

[0094] For example, the current output torque T p2 of the P2 motor is 50 NM, the current speed N P2 of the P2 motor is 2000 rpm, and the efficiency η2 of the P2 motor is 85%, and the calculation can obtain the current vehicle driving power P D = ((50*2000) / 9550*85)*100 ≈ 12.32 KW.

[0095] Further, after calculating the discharge power of the power battery, the driving power of the vehicle, and the power generation of the target motor, the driving power of the vehicle can be determined based on the discharge power of the power battery, the driving power of the vehicle, and the power generation of the target motor.

[0096] In steps 202 and 203, it can be understood that the sum of the discharge power of the power battery and the power generation of the target motor can be understood as the total output power that the vehicle can currently output; and the driving power of the vehicle can be understood as the current demand power of the vehicle.

[0097] Further, based on the size relationship between the total output power and the demand power of the vehicle, the current demand power of the vehicle can be determined, and the strategy for the torque reduction operation before mode switching can be further determined.

[0098] Specifically, the target interval in which the vehicle driving power is located can be determined based on the size relationship between the total output power of the vehicle (i.e., the sum of the discharging power of the power battery and the power generation of the target motor) and the demand power (i.e., the vehicle driving power), and the target torque reduction gradient corresponding to the target interval is determined.

[0099] The target interval can include a low power demand interval and a high power demand interval.

[0100] When the vehicle driving power is less than or equal to the discharging power of the power battery, it means that the discharging power of the power battery can meet the current driving demand of the vehicle, indicating that the current demand power of the vehicle is low, i.e., the vehicle driving power is determined to be in the low power demand interval.

[0101] When the vehicle driving power is greater than the discharging power of the power battery and less than or equal to the total output power of the vehicle, it means that the sum of the discharging power of the power battery and the power generation of the target motor can meet the current driving demand of the vehicle, indicating that the current demand power of the vehicle is high, i.e., the vehicle driving power is determined to be in the high power demand interval.

[0102] Further, as described above, during the process of switching the driving mode of the vehicle from the series mode to the direct drive mode, the clutch is usually controlled to be opened, and in order to reduce the impact on mechanical parts and prevent the vehicle from stalling, the torque of the engine is usually controlled to be reduced to a certain value before the clutch is controlled to be opened. Based on this, the embodiments of the present application can determine different torque reduction gradients according to the high and low of the current demand power of the vehicle, thereby further ensuring the driving smoothness of the vehicle during the mode switching process.

[0103] In a possible implementation, the target interval in which the vehicle driving power is located is determined based on the discharging power of the power battery, the vehicle driving power and the power generation of the target motor, and the target torque reduction gradient corresponding to the target interval is determined, including: in the case that the vehicle driving power is less than or equal to the discharging power of the power battery, determining that the target interval is a first interval, and determining the first torque reduction gradient corresponding to the first interval as the target torque reduction gradient; in the case that the vehicle driving power is greater than the discharging power of the power battery and less than or equal to the sum of the discharging power of the power battery and the power generation of the target motor, determining that the target interval is a second interval, and determining the second torque reduction gradient corresponding to the second interval as the target torque reduction gradient; wherein the first torque reduction gradient is greater than the second torque reduction gradient.

[0104] The target interval can include a first interval and a second interval; the first interval is the low power demand interval described above; and the second interval is the high power demand interval described above. The target torque reduction gradient can include a first torque reduction gradient corresponding to the first interval and a second torque reduction gradient corresponding to the second interval.

[0105] As mentioned earlier, when the vehicle's driving power is in the first range (i.e., the low power demand range), it means that the vehicle's current power demand is low, and the power battery's discharge power is sufficient to meet the vehicle's current driving needs. At this point, there is no need to rely on the target motor's power generation to drive the vehicle. Even if the engine torque is rapidly reduced, it will not affect the vehicle's current power performance or significantly impact its smoothness. Therefore, the target torque reduction gradient corresponding to the first range can be set to a relatively high first torque reduction gradient.

[0106] When the vehicle's driving power is in the second range (i.e., the high power demand range), it means that the vehicle's current power demand is high, requiring simultaneous reliance on the discharge power of the power battery and the power generation power of the target motor to drive the vehicle. Since the target motor relies on the engine to generate electricity, rapidly reducing the engine torque at this time will cause the target motor's power generation power to also decrease rapidly, resulting in a loss of vehicle power. This severely affects the vehicle's driving smoothness and may also pose safety risks due to power interruption. Therefore, the target torque reduction gradient corresponding to the second range can be set to a relatively low second torque reduction gradient.

[0107] Figure 3 This is a schematic diagram of the control process for switching from a series mode to a direct drive mode, provided in an embodiment of this application.

[0108] For example, such as Figure 3 As shown, the vertical axis represents the vehicle's current total driving power, in kW; the horizontal axis represents the vehicle's current speed, in kilometers per hour (km / h).

[0109] exist Figure 3 In this process, based on the discharge power curve of the power battery, the total output power curve in series mode, the theoretical direct-drive vehicle drive power boundary, the vehicle drive power boundary after the clutch is disengaged during the mold-changing process, the power shuffling curve of the torque reduction stage from series to direct drive, and the power release curve of the torque increase stage from series to direct drive, the following parameters can be used to divide the power into three parts: Figure 3 The three power regions are region 1, region 2 and region 3.

[0110] The discharge power curve of the power battery can be calculated in real time by the BMS. Specifically, the BMS collects the voltage, current, temperature, and current remaining capacity of the power battery, and then determines the discharge power that the power battery can stably output by combining the pre-calibrated discharge power-battery parameter MAP graph. Specifically, when the vehicle is in series mode and the current vehicle speed is low, the discharge power of the power battery can be used to drive the vehicle, so the discharge power curve of the power battery in series mode remains stable when the vehicle speed is low. During the switching process of the driving mode of the vehicle from series mode to direct drive mode, the dependence on the power battery is reduced because the engine directly drives in direct drive mode, so as the vehicle speed increases, the discharge power curve of the power battery shows a trend of "decreasing with the increase of vehicle speed".

[0111] The total output power curve in series mode can be calculated by the vehicle controller according to the power demand in series mode and the output capability of the power source. Specifically, the total output power in series mode is usually the sum of the discharge power of the power battery and the power generation power of the target motor. The power generation power of the target motor is usually affected by the speed and torque of the engine (the engine drives the target motor to generate power, and when the engine speed or torque is greater, the power generation power of the target motor is also greater). When the vehicle is in series mode and the current vehicle speed is low, the output torque of the engine is used to drive the target motor to generate power, so the total output power curve in series mode remains stable when the vehicle speed is low. During the switching process of the driving mode of the vehicle from series mode to direct drive mode, the power generation power of the target motor gradually decreases because the output torque of the engine gradually changes from "power generation" to "direct driving of the vehicle", and the discharge power of the power battery also gradually decreases during this mode. That is, during the switching process of the driving mode of the vehicle from series mode to direct drive mode, the power generation power of the target motor and the discharge power of the power battery both gradually decrease, so as the vehicle speed increases, the total output power curve in series mode also shows a trend of "decreasing with the increase of vehicle speed".

[0112] The theoretical direct drive vehicle driving power boundary refers to the upper limit value of the vehicle driving power that the direct drive mode can provide in an ideal state. This power value is based on the optimal performance of the engine at different speeds and is calibrated, reflecting the power level that the engine can achieve in direct drive mode when fully exerting its power output capability. In direct drive mode, the corresponding theoretical direct drive vehicle driving power boundary can usually be determined on the pre-established power-speed characteristic curve of the engine based on the speed, torque, and transmission ratio of the engine.

[0113] The vehicle drive power boundary after clutch disengagement during the mold-changing process refers to the minimum stable vehicle drive power that direct drive mode can provide during the mold-changing process. Specifically, when the vehicle's drive mode switches from series mode to direct drive mode, the power transmission method changes after the clutch disengages, allowing the engine to gradually drive the wheels directly. However, due to the transitional power connection at the moment the clutch disengages, and factors such as the potential matching of engine and wheel speeds, the actual vehicle drive power output at the initial engagement of direct drive mode is limited. This limitation is the vehicle drive power boundary after clutch disengagement during the mold-changing process. Typically, extensive real-vehicle testing and simulation experiments can record the actual vehicle drive power transmitted from the engine to the wheels in direct drive mode at the moment the clutch disengages under different operating conditions. During actual mode switching, the vehicle drive power boundary corresponding to the current operating condition can be determined based on the recorded data.

[0114] The power shuffling curve during the series-to-direct-drive torque reduction phase refers to the curve showing the change in overall vehicle drive power as the engine torque is gradually reduced during the transition from series to direct-drive mode. This is done to ensure a smooth power transition and avoid sudden torque changes affecting vehicle stability and ride comfort. The aforementioned power shuffling curve during the series-to-direct-drive torque reduction phase can typically be plotted based on the current engine's torque reduction gradient.

[0115] The power release curve during the series-driven direct-drive torque-increase phase refers to the change in overall vehicle drive power as the engine torque is increased in a certain gradient after the clutch is disengaged to meet the vehicle's power demands and ensure smooth operation. This power release curve during the series-driven direct-drive torque-increase phase can typically be plotted based on the current engine's torque-increase gradient.

[0116] For example, the power region below the discharge power curve of the power battery can be defined as Region 1; the region above the discharge power curve of the power battery, below the total output power curve in series mode, and to the left of the power shaving curve in the series-to-direct-drive torque reduction stage can be defined as Region 2; the region below the theoretical direct-drive vehicle drive power boundary, above the vehicle drive power boundary after the clutch is opened during the mold change process, to the right of the power shaving curve in the series-to-direct-drive torque reduction stage, and to the left of the power release curve in the series-to-direct-drive torque increase stage can be defined as Region 3.

[0117] Furthermore, such as Figure 3 As shown, when the vehicle's driving power is less than or equal to the power battery's discharge power, that is, when the value corresponding to the vehicle's driving power is below the power battery's discharge power curve or falls exactly on the power battery's discharge power curve, the vehicle's driving power is determined to be in region 1.

[0118] In a case that the driving power of the vehicle is greater than the discharging power of the power battery and less than or equal to the total output power of the vehicle in the series mode (i.e., the sum of the discharging power of the power battery and the power generation power of the target motor), i.e., the value corresponding to the driving power of the vehicle is above the discharging power curve of the power battery, and the value corresponding to the driving power of the vehicle is below or just falls on the total output power curve in the series mode, and the value corresponding to the driving power of the vehicle is to the left of the power slow-cut curve in the series-to-direct-drive torque reduction phase, it can be determined that the driving power of the vehicle is in the region 2.

[0119] It can be understood that the above-mentioned region 1 can be understood as the first interval described above; and the above-mentioned region 2 can be understood as the second interval described above.

[0120] The above method determines the target interval in which the driving power of the vehicle is located, and determines the target torque reduction gradient corresponding to the target interval, so as to accurately match the power demand in different working conditions, and thus determine the torque reduction gradient in different working conditions. In a case that the driving power of the vehicle is less than or equal to the discharging power of the power battery, it is determined that the driving power of the vehicle is in the first interval with lower power demand, and a larger first torque reduction gradient is determined as the target torque reduction gradient, so that the torque can be rapidly reduced in the low power demand, and even if the torque is rapidly reduced, the smoothness of the vehicle will not be greatly affected, and subsequent rapid mode switching can be facilitated, and power interruption can be avoided. In a case that the driving power of the vehicle is greater than the discharging power of the power battery and less than or equal to the sum of the discharging power of the power battery and the power generation power of the target motor, it is determined that the driving power of the vehicle is in the second interval with higher power demand, and a smaller second torque reduction gradient is determined as the target torque reduction gradient, so that the torque can be slowly reduced in the high power demand, and the continuity of the power is ensured, so that the power interruption caused by the direct reduction of the engine torque to zero can be avoided.

[0121] Generally, in the process of switching the driving mode of the vehicle from the series mode to the direct-drive mode, the clutch needs to be opened. The engine is connected with the gearbox through the clutch, and the clutch is in a closed state when the vehicle is driven in the series mode, and the engine outputs a certain torque at this time. When the clutch needs to be opened, in order to ensure that the clutch is safely opened, the torque of the engine needs to be controlled to reduce to a target torque at which the clutch can be safely opened.

[0122] The torque of the engine generally includes two parts of a fire road torque and an air road torque, and the target torque corresponding to each of the fire road and the air road needs to be determined, which will be described in the following embodiments.

[0123] In one possible implementation, the target torque includes a target fire circuit torque and a target air circuit torque. The target torque is determined by the following methods: determining the original air circuit torque request value based on the driver's required torque, the target front and rear axle torque distribution ratio, and the actual torque of the target motor; determining the target fire circuit torque based on the original air circuit torque request value, the shift intervention torque, and the engine fire circuit speed control torque; and determining the target air circuit torque based on the original air circuit torque request value, the engine air circuit torque reserve, the engine air circuit speed control torque reserve, and the target fire circuit torque.

[0124] Among them, the driver's required torque refers to the vehicle's required torque determined based on the driver's operation. Specifically, the vehicle can store the correspondence between various accelerator pedal openings and the corresponding driver's required torque. It can obtain the current accelerator pedal opening and determine the driver's required torque corresponding to that accelerator pedal opening based on the correspondence.

[0125] The target front-to-rear axle distribution ratio refers to the ratio between the torque required by the entire vehicle and the torque required by the rear axle, after the total torque requirement of the vehicle has been determined. For example, if the total torque requirement of the vehicle is 100 Nm, and 80 N is distributed to the front axle and 20 N to the rear axle, then the target front-to-rear axle distribution ratio is front axle:rear axle = 8:2.

[0126] In some embodiments, the vehicle's driving mode affects the aforementioned front-to-rear axle distribution ratio. For example, in Eco mode, to improve fuel economy, the vehicle may be biased towards single-axle drive (such as pure electric rear-wheel drive) to reduce energy consumption; in this case, the distribution ratio is front axle:rear axle = 0:10. In Sport mode, a distribution closer to 5:5 may be used to improve handling. In Four-Wheel Drive mode or Off-Road mode, a more balanced or rear-axle-biased distribution may be used to enhance off-road capability; in this case, the distribution ratio could be, for example, front axle:rear axle = 3:7. Therefore, the aforementioned target front-to-rear axle distribution ratio can be determined based on the vehicle's driving mode.

[0127] It is understood that the target front and rear axle allocation ratio can be a pre-set fixed value or be affected by other parameters. The above method for determining the target front and rear axle allocation ratio is only an example, and this application embodiment does not limit it.

[0128] The target motor is a motor that is rigidly connected to the gearbox, i.e. Figure 1 The front-drive motor 103 is located in the engine. The target motor is connected to the engine via a clutch. The power battery can provide electrical energy to the target motor to enable it to output torque. The actual torque of the target motor, i.e., the torque currently output by the target motor, can be obtained based on a torque sensor installed on the target motor.

[0129] The target torque of the engine can include both a target fire path torque and a target air path torque. The target fire path torque refers to a portion of the target torque achieved by adjusting the ignition system (mainly the ignition advance angle) and the fuel injection strategy (such as multiple injections) to optimize the combustion process of the mixture in the cylinder. The target air path torque refers to a portion of the target torque achieved by adjusting the intake system (mainly the throttle opening, variable valve timing, etc.) to control the amount of air entering the engine cylinder.

[0130] The original air path torque request value refers to the air path torque value requested by the vehicle under the current operating state without performing a shift action. After obtaining the driver demand torque, the target front-rear axle torque distribution ratio, and the actual torque of the target motor, the original air path torque request value can be calculated based on the driver demand torque, the target front-rear axle torque distribution ratio, and the actual torque of the target motor.

[0131] The process of calculating the original air path torque request value includes: determining the front axle distribution ratio based on the target front-rear axle torque distribution; multiplying the driver demand torque by the front axle distribution ratio to obtain the front axle distribution torque; subtracting the actual torque of the target motor from the front axle distribution torque to obtain the original air path torque request value. The formula for calculating the original air path torque request value is shown in the following formula (4):

[0132] T3 = T1 * λ - T2 (4)

[0133] In the above formula (4), T3 is the original air path torque request value, T1 is the driver demand torque, λ is the front axle torque distribution ratio, and T2 is the actual torque of the target motor.

[0134] For example, the driver demand torque T1 is 100 NM, the target front-rear axle torque distribution ratio is front axle: rear axle = 3:7, and the front axle torque distribution ratio λ is 0.3. The actual torque of the target motor T2 is 20 NM, and the original air path torque request value T3 calculated based on the above formula (4) is 100 * 0.3 - 20 = 10 NM.

[0135] The shift intervention torque refers to the torque used to indicate the torque reduction of the engine. The shift intervention torque is usually the actual torque of the engine minus the target torque reduction gradient. As the shift intervention torque indicates the actual torque of the engine, the shift intervention torque gradually decreases until the shift intervention torque equals the target torque.

[0136] The engine fire road speed control torque refers to a torque for controlling the engine to maintain a certain speed after the clutch is opened. The engine fire road speed control torque can be determined based on a difference between a current speed of the engine and a speed to be maintained. For example, after the clutch is opened, the engine needs to be maintained at 1500 rpm, and the current speed of the engine is lower than 1500 rpm, the engine fire road speed control torque is increased to increase the current speed of the engine to 1500 rpm. If the current speed of the engine is higher than 1500 rpm, the engine fire road speed control torque is reduced to reduce the speed of the engine to 1500 rpm.

[0137] After the original air path torque request value, the shift intervention torque and the engine fire road speed control torque are obtained, the target fire road torque can be calculated based on the original air path torque request value, the shift intervention torque and the engine fire road speed control torque.

[0138] The process of calculating the target fire road torque includes: determining the minimum value between the original air path torque request value and the shift intervention torque as an initial torque; in the case that the initial torque is greater than zero, determining the sum of the initial torque and the engine fire road speed control torque as the target fire road torque; in the case that the initial torque is less than zero, determining the engine fire road speed control torque as the target fire road torque. The formula for calculating the target fire road torque is shown in the following formula (5):

[0139] T6 = max(min(T3, T4), 0) + T5 (5)

[0140] In the above formula (5), T6 is the target fire road torque, T3 is the original air path torque request value, T4 is the shift intervention torque, and T5 is the engine fire road speed control torque.

[0141] For example, the original air path torque request value T3 is 60 NM, the shift intervention torque T4 is 30 NM, and the engine fire road speed control torque is 0 NM. Based on the above formula (5), the target fire road torque T6 = max(min(60, 30), 0) + 0 = 30 NM can be calculated.

[0142] It can be understood that during the mode switching process, the shift intervention torque T4 will decrease to 0 NM from the current actual torque of the engine according to the gradient, resulting in that the target fire road torque T6 will also decrease to 0 NM. When the clutch is opened for speed regulation, the engine fire road speed control torque is used for speed regulation, and when the target speed is reached, the engine fire road speed control torque will be close to 0 NM, so that the final target fire road torque is reduced to 0 NM.

[0143] The engine air path reserved torque refers to an adjustment amount of the engine air path torque currently required to be adjusted. The vehicle stores a first mapping table between the engine speed, the original air path torque request value and the engine air path reserved torque. After obtaining the original air path torque request value, the current engine speed can be obtained, and based on the speed and the original air path torque request value, the first mapping table is searched to obtain the engine air path reserved torque. The first mapping table is shown in Table 1 as follows:

[0144] Table 1

[0145] Y / X 0 800 1000 1200 1500 1800 2100 2400 3000 -10 0 0 30 30 30 30 30 30 30 10 0 0 10 10 10 10 10 10 10 20 0 0 0 0 0 0 0 0 0 70 0 0 -50 -50 -50 -50 -50 -50 -50 100 0 0 -80 -80 -80 -80 -80 -80 -80

[0146] In Table 1, Y is the original air path torque request value, with units of NM, and X is the engine speed, with units of rpm. As shown in Table 1, in the first mapping table, when the engine speed is less than a certain speed (for example, 800 rpm in Table 1), the engine air path reserved torque is 0 regardless of whether the original air path torque request value of the engine is positive or negative, at which time the air path torque of the engine does not need to be adjusted. When the speed is greater than a certain speed (for example, 800 rpm in Table 1), after the original air path torque request value of the engine is adjusted based on the engine air path reserved torque, the adjusted air path torque value is usually maintained at a preset fixed value.

[0147] It can be understood that during the engine torque reduction process, when the difference between the fire path torque and the air path torque is too large, the engine fuel consumption is large, at which time the economy of the vehicle is poor. The above-mentioned preset fixed value is a target value of the air path torque reduction that can both ensure the rapid recovery of the engine and reduce fuel consumption.

[0148] As shown in Table 1, the adjusted air path torque of the engine usually needs to be maintained at 20 NM, and as shown in Table 1, when the original air path torque request value is 20 NM, the engine air path reserved torque is 0; when the original air path torque request value is less than 20 NM, the engine air path reserved torque is positive; and when the original air path torque request value is greater than 20 NM, the engine air path reserved torque is negative. Overall, when the engine speed is greater than or equal to 1000 rpm, the greater the original air path torque request value, the smaller the engine air path reserved torque, and the smaller the original air path torque request value, the greater the engine air path reserved torque, ultimately ensuring that the adjusted engine air path torque is maintained at about 20 NM; when the engine speed is less than 1000 rpm, the engine air path reserved torque is zero, i.e., the engine air path torque is not adjusted.

[0149] The engine air path speed control reserved torque refers to a value used to keep the fluctuation of the engine air path torque consistent with the fluctuation of the engine fire path torque. The engine air path speed control reserved torque can be determined based on the engine fire path speed control torque.

[0150] It can be understood that the engine air path torque will fluctuate when maintaining the speed of the engine, and the value causing the fluctuation is the engine fire path speed control torque. In order to keep the fluctuation of the air path torque consistent with the fluctuation of the fire path torque, the engine air path speed control reserved torque can be determined based on the fire path speed control torque at this time.

[0151] After obtaining the original air path torque request value, the engine air path reserved torque, the engine air path speed control reserved torque, and the target fire path torque, the target air path torque can be determined based on the original air path torque request value, the engine air path reserved torque, the engine air path speed control reserved torque, and the target fire path torque.

[0152] The process of calculating the target air path torque includes: adding the original air path torque request value and the engine air path reserved torque to obtain an intermediate value, adding the intermediate value to the engine air path speed control reserved torque to obtain an initial target air path torque, and determining the maximum value between the initial target air path torque and the target fire path torque as the target air path torque. The formula for calculating the target air path torque is shown in the following formula (6):

[0153] T9 = max (T3 + T7 + T8, T6) (6)

[0154] In the above formula (6), T9 is the target air path torque, T3 is the original air path torque request value, T7 is the engine air path reserved torque, T8 is the engine air path speed control reserved torque, and T6 is the target fire path torque.

[0155] For example, the original air path torque request value T3 is 10 NM, the engine air path reserved torque T7 is 10 NM, the engine air path speed control reserved torque T8 is 0 NM, and the target fire path torque T6 is 0 NM. The target air path torque T9 = max (10 + 10 - 0, 0) = 20 NM can be calculated based on the above formula (6).

[0156] In the above method, the engine fire path target torque can be dynamically calculated in real time based on the original air path torque request value, the shift intervention torque, and the engine fire path speed control torque, while considering the engine fire path speed control torque, which can ensure that the engine maintains a certain speed when the clutch is opened, avoiding engine damage caused by excessively high or low engine speed. The target air path torque can be calculated based on the original air path torque, the engine air path reserved torque, the engine air path speed control reserved torque, and the fire path target torque, which can ensure that the engine air path reserved torque is not less than the fire path target torque and fluctuates with the fluctuation of the target fire path torque, ensuring the accuracy of the target torque control.

[0157] As described above, in order to ensure the driving comfort during the mold changing process, the target torque reduction gradient can be determined and the engine torque reduction is controlled according to the target torque reduction gradient.

[0158] In a possible implementation, the target torque reduction gradient is determined by: obtaining an original air path torque request value of the engine and a current opening degree of an accelerator pedal of the vehicle; calculating a current power difference between the vehicle driving power and the power battery discharge power; determining the target torque reduction gradient based on the current power difference, the original air path torque request value and the current opening degree of the accelerator pedal.

[0159] The original air path torque request value refers to a torque demand value sent by a controller of the vehicle to the engine through an air path. As in the above embodiment, the original air path torque request value can be calculated based on formula (4).

[0160] The current stroke of the accelerator pedal can be detected based on a position sensor arranged at the accelerator pedal, and the current opening degree of the accelerator pedal can be calculated based on the current stroke of the accelerator pedal.

[0161] The vehicle driving power can be subtracted by the power battery discharge power to obtain the power difference.

[0162] As in the above embodiment, based on the vehicle driving power, the power battery discharge power and the target motor power generation, a plurality of intervals can be divided, and a corresponding relationship for searching the target torque reduction gradient in each interval is stored in the vehicle. Based on the current obtained vehicle driving power, power battery discharge power and target motor power generation, the target interval in which the vehicle currently locates can be determined, and the corresponding relationship in the target interval is determined as the target corresponding relationship.

[0163] Further, after the target corresponding relationship is determined, the target torque reduction gradient can be searched based on the original air path torque request value, the accelerator pedal opening degree and the power difference.

[0164] In a possible implementation, the target torque reduction gradient is determined based on the current power difference, the original air path torque request value and the current opening degree of the accelerator pedal, including: determining a basic torque reduction gradient corresponding to the current power difference and the original air path torque request value based on a first corresponding relationship corresponding to the target interval; the first corresponding relationship is a corresponding relationship between the basic torque reduction gradient and two parameters of the power difference and the air path torque request value; the power difference is a difference between the vehicle driving power and the power battery discharge power; determining a first target correction coefficient corresponding to the current power difference and the current opening degree of the accelerator pedal based on a second corresponding relationship corresponding to the target interval; the second corresponding relationship is a corresponding relationship between the correction coefficient and two parameters of the power difference and the opening degree of the accelerator pedal; and determining the target torque reduction gradient based on the basic torque reduction gradient and the first target correction coefficient.

[0165] The target correspondence relationship includes a first correspondence relationship for determining the basic torque reduction gradient and a second correspondence relationship for determining the first target correction coefficient.

[0166] The first correspondence relationship is specifically a correspondence relationship between the power difference, the original air path torque request value, and the basic torque reduction gradient.

[0167] It can be understood that when the vehicle driving power is less than or equal to the discharge power of the power battery, the power interval is the first interval, and thus the power difference calculated in the first interval is less than or equal to 0. When the vehicle driving power is greater than the discharge power of the power battery, the power interval is the second interval, and thus the power difference calculated in the second interval is greater than 0.

[0168] The first correspondence relationship can be as shown in Table 2 below:

[0169] Table 2

[0170]

[0171] In Table 2, Y is the original air path torque request value, in units of NM, and Z is the power difference, in units of KW. Table 2 includes the first correspondence relationship corresponding to the first interval and the first correspondence relationship corresponding to the second interval. As shown in Table 2, the power difference in the first correspondence relationship in the first interval is less than or equal to 0, and the torque reduction gradient is 1100 NM / s. The power difference in the first correspondence relationship in the second interval is greater than 0, and the torque reduction gradient is less than 1100 NM / s. Specifically, in the first correspondence relationship in the second interval, when the original air path torque request value is less than or equal to a preset value (for example, 20 NM in Table 2), the torque reduction gradient remains unchanged and is 900 NM / s. When the original air path torque request value is greater than the preset value, the torque reduction gradient decreases with the increase of the power difference under the condition that the original air path torque request value is fixed, and the torque reduction gradient decreases with the increase of the original air path torque request value under the condition that the power difference is fixed.

[0172] It can be understood that the vehicle driving power in the first interval is less than or equal to the discharge power of the power battery, and thus the power difference in the first correspondence relationship in the first interval is less than or equal to 0. In the first interval, in order to avoid the engine torque from decreasing too slowly and causing the vehicle to enter the second interval, a large torque reduction gradient is needed to achieve rapid mode switching, and thus the torque reduction gradient in the first correspondence relationship in the first interval is a large torque reduction gradient of 1100 NM / s.

[0173] The whole vehicle driving power in the second interval is greater than the discharging power of the power battery and less than or equal to the sum of the discharging power of the power battery and the power generation power of the target motor, and therefore the power difference in the first corresponding relationship in the second interval is greater than 0. In order to ensure the smoothness of the mode switching process and the power not being lost in the mode switching process, a smaller torque reduction gradient is needed to reduce the torque fluctuation at this time, and therefore the torque reduction gradient in the first corresponding relationship in the second interval is usually smaller than the torque reduction gradient in the first corresponding relationship in the first interval.

[0174] When the whole vehicle driving power is greater than the discharging power of the power battery, the power battery is prone to over-discharge, and the greater the power difference, the greater the risk of over-discharge of the power battery. Therefore, the greater the power difference, the smaller the torque reduction gradient is needed to reduce the safety problem of the power battery caused by the change of engine torque. The greater the engine air path torque request value, the higher the load of the engine. At this time, a smaller torque reduction gradient can make the working state of the engine change more gently, reduce the impact load on the internal parts of the engine such as the piston, connecting rod and crankshaft, and help to prolong the service life of the engine parts and reduce the risk of damage to the engine due to the sharp change of torque. Therefore, in the first corresponding relationship in the second interval, when the original air path torque request value is greater than the preset value, the torque reduction gradient is in a decreasing trend with the increase of the power difference under the condition that the original air path torque request value is fixed, and the torque reduction gradient is in a decreasing trend with the increase of the original air path torque request value under the condition that the power difference is fixed.

[0175] When the original air path torque request value is less than or equal to the preset value, it can be determined that the torque output by the engine is small, and the fluctuation of the engine torque also has a small impact on the power battery. At this time, a fixed larger torque reduction gradient can be used for torque reduction.

[0176] The above table 2 is only an example. In some embodiments, the first corresponding relationship in the first interval in table 2 can also be in a decreasing trend with the increase of the power difference under the condition that the original air path torque request value is fixed, and in a decreasing trend with the increase of the original air path torque request value under the condition that the power difference is fixed.

[0177] The above second corresponding relationship is specifically a corresponding relationship between the power difference, the accelerator pedal opening degree and the first target correction coefficient.

[0178] The above second corresponding relationship is specifically shown in the following table 3:

[0179] Table 3

[0180]

[0181] In Table 3, W is the accelerator pedal opening degree, and Z is the power difference. Table 3 includes the second correspondence relationship in the first interval and the second correspondence relationship in the second interval. As shown in Table 3, in the second correspondence relationship in the first interval, when the accelerator pedal opening degree is less than or equal to the first opening degree (for example, 50% in Table 3), the first target correction coefficient is 1, and the basic torque reduction gradient does not need to be corrected. When the accelerator pedal opening degree is greater than the first opening degree (for example, 50% in Table 3), the first target correction coefficient is greater than 1, and the basic torque reduction gradient needs to be enlarged to obtain a larger torque reduction gradient. Specifically, when the accelerator pedal opening degree is greater than the first opening degree (for example, 50% in Table 3), the first target correction coefficient increases with the increase of the accelerator pedal opening degree.

[0182] As shown in Table 3, in the second correspondence relationship in the second interval, when the accelerator pedal opening degree is greater than or equal to the second opening degree (for example, 80% in Table 3) and the power difference is less than or equal to the first difference (for example, 20 KW in Table 3), the first target correction coefficient is greater than 1, and the basic torque reduction gradient needs to be enlarged to obtain a larger torque reduction gradient. Specifically, the first target correction coefficient decreases with the increase of the power difference and increases with the increase of the accelerator pedal opening degree. When the accelerator pedal opening degree is less than the second opening degree (for example, 80% in Table 3) or the power difference is greater than the first difference (for example, 20 KW in Table 3), the first target correction coefficient is 1, and the basic torque reduction gradient does not need to be corrected. The second opening degree is slightly greater than the first opening degree.

[0183] It can be understood that in the first interval, the vehicle driving power is less than the discharging power of the power battery. When the accelerator pedal opening degree of the vehicle is large, the power demand of the vehicle is large, which may cause the vehicle driving power to be greater than the discharging power of the power battery, so that the vehicle enters the second interval. At this time, the torque reduction gradient can be corrected to a large value to quickly reduce the torque output by the engine and reduce the vehicle driving power. Therefore, in the second correspondence relationship in the first interval, when the accelerator pedal opening degree is greater than the first opening degree, the first target correction coefficient is greater than 1, which is used to enlarge the basic torque reduction gradient. The greater the accelerator pedal opening degree, the greater the power demand, and therefore a larger torque reduction gradient is needed to reduce the torque of the engine to ensure that the vehicle driving power is less than the discharging power of the power battery. Therefore, in the second correspondence relationship in the first interval, when the accelerator pedal opening degree is greater than the first opening degree, the first target correction coefficient increases with the increase of the accelerator pedal opening degree.

[0184] The whole vehicle driving power of the vehicle in the second interval is greater than the discharging power of the power battery, the whole vehicle driving power exceeds the discharging power of the power battery less in the case that the power difference is small, and the second interval is adjacent to the first interval at this time. In the second corresponding relationship in the second interval, the first target correction coefficient is greater than 1 when the accelerator pedal opening degree is greater than the first opening degree. In order to avoid the change of the torque reduction gradient being too large after the vehicle enters the second interval from the first interval, in the second corresponding relationship in the second interval, the first target correction coefficient is also greater than 1 when the accelerator pedal opening degree is greater than the second opening degree, so as to realize the transition of the torque reduction gradient and avoid the torque reduction gradient suddenly decreasing greatly. In the second interval, as the power difference increases, the vehicle needs to reduce the torque based on a smaller torque reduction gradient, so in the second corresponding relationship in the second interval, the first target correction coefficient is in a decreasing trend as the power difference increases when the accelerator pedal opening degree is greater than the second opening degree. When the accelerator pedal opening degree is greater than the second opening degree, the first target correction coefficient needs to follow the trend of the first target correction coefficient in the first interval as the accelerator pedal opening degree increases. Since in the first interval, the first target correction coefficient is in an increasing trend as the accelerator pedal opening degree increases when the accelerator pedal opening degree is greater than the first opening degree, therefore, in the second interval, the first target correction coefficient is in an increasing trend as the accelerator pedal opening degree increases when the accelerator pedal opening degree is greater than the second opening degree and the power difference is less than or equal to the first difference.

[0185] It can be understood that the first corresponding relationship and the second corresponding relationship shown in Table 2 and Table 3 are only an example, and the embodiments of the present application are not limited thereto.

[0186] For example, when it is determined that the whole vehicle driving power is in the first interval, the first corresponding relationship corresponding to the first interval can be determined in Table 2, and the second corresponding relationship corresponding to the first interval can be determined in Table 3. Assuming that the power difference is -10KW, the original air path torque request value is 50NM, and the accelerator pedal opening degree is 80%, based on Table 2, the basic torque reduction gradient can be determined to be 1100NM / s, and based on Table 3, the first target correction coefficient can be determined to be 1.5.

[0187] After obtaining the basic torque reduction gradient and the first target correction coefficient, the basic torque reduction gradient can be multiplied by the target coefficient to obtain the target torque reduction gradient, that is, the target torque reduction gradient = 1100*1.5 = 1650NM / s.

[0188] In the method, when determining the basic torque reduction gradient, the power difference and the original air path torque request value are considered. The power difference can reflect the size relationship between the vehicle driving power and the discharge power of the power battery, and then can reflect the over-discharge situation of the power battery. The greater the power difference, the greater the risk of over-discharge of the power battery. The determined basic torque reduction gradient can ensure that the over-discharge situation of the power battery is avoided. The original air path torque request value can represent the high load working state of the engine, so that the determined basic torque reduction gradient avoids the high load of the engine. The accelerator pedal opening degree can represent the power demand. The first target correction coefficient is determined based on the accelerator pedal opening degree and the power difference to correct the basic torque reduction gradient, so that the target torque reduction gradient can consider the current power demand of the vehicle, and the accuracy of the torque reduction control is further improved.

[0189] Further, in the process of controlling the torque reduction of the engine, the "fire path" and the "air path" are two different torque adjustment paths.

[0190] The fire path torque refers to the torque adjustment achieved by controlling the ignition angle, such as adjusting the fire path torque by adjusting the ignition advance angle. Generally, the response speed is fast when adjusting the fire path torque, and therefore, the fire path torque can also be referred to as "fast path torque".

[0191] The air path torque refers to the torque adjustment achieved by controlling the intake air amount, such as adjusting the air path torque by adjusting the throttle opening. Generally, the response speed is slow when adjusting the air path torque, and therefore, the air path torque can also be referred to as "slow path torque".

[0192] Currently, in the process of switching the driving mode of the vehicle from the series mode to the direct drive mode, the fire path torque is usually reduced in the process of controlling the torque reduction of the engine, and in order to ensure that the engine output torque can be quickly restored when entering the direct drive mode, the air path torque is usually not reduced. However, the inventors of the present application have found through research that, in the process of switching from the series mode to the direct drive mode, if the air path torque is not reduced, it will have an impact on the operation of the engine, such as the air-fire separation being too serious due to the large difference between the air path torque and the fire path torque, which leads to insufficient engine combustion, and further leads to problems such as increased fuel consumption and excessive emissions. Therefore, in the embodiments of the present application, the air path torque is reduced at the same time as the fire path torque is reduced, and the absolute value of the torque difference between the fire path torque and the air path torque is maintained within a certain range during the torque reduction process, thereby preventing the engine from being separated due to the large difference between the air path torque and the fire path torque.

[0193] For example, the above-mentioned preset difference can be set according to actual needs, such as being set to 20 NM, that is, the torque difference between the fire path torque and the air path torque needs to be ensured to be less than or equal to 20 NM during the torque reduction process.

[0194] In the process of controlling engine torque reduction, the fire path torque can be reduced by controlling the ignition angle release (such as delaying the ignition angle to an "ineffective combustion" angle). However, if the controller randomly or blindly controls the ignition angle release, it may cause the fire path torque to be out of control, the emission to be seriously over-standard, and other problems. Based on this, before controlling the ignition angle release, the adjustment range of the ignition angle can be determined first, and then the ignition angle release can be controlled based on the adjustment range of the ignition angle.

[0195] In some embodiments, a mapping relationship table between the two parameters of intake volume and rotation speed and the adjustment range of the ignition angle can be established in advance. In actual application, the corresponding target adjustment range of the ignition angle can be determined in the mapping relationship table based on the current intake volume of the engine and the current rotation speed of the engine.

[0196] For example, the process of establishing the above mapping relationship table can be: under the same intake volume and the same rotation speed, gradually increasing the ignition advance angle (adjusting in the "advance" direction) from zero, while measuring the current fire path torque. As the ignition advance angle increases, the combustion time becomes more sufficient, and the fire path torque gradually rises. If the fire path torque rises to a certain torque value (peak value) and the ignition advance angle continues to increase, the fire path torque will no longer continue to rise, indicating that the maximum torque value corresponding to the fire path torque has been reached, and the ignition advance angle at this time is the optimal ignition angle under the current intake volume and the current rotation speed. The optimal ignition angle is recorded as θ0.

[0197] Further, keeping the above intake volume and rotation speed unchanged, starting from the optimal ignition angle determined above, gradually delaying the ignition advance angle (adjusting in the "lag" direction), while measuring the current fire path torque. As the ignition advance angle is delayed, the combustion time is shortened and the combustion efficiency is decreased, resulting in a gradual decrease in the fire path torque. If the ignition advance angle is delayed to a certain angle, the fire path torque decreases to a certain limit value (at this time the mixed gas in the engine can continue to burn), and if the ignition advance angle continues to be delayed, the mixed gas in the engine will not be able to burn and the fire path torque will directly drop to zero, indicating that it has decreased to the minimum torque value corresponding to the fire path torque. At this time, the ignition advance angle is the latest ignition angle under the current intake volume and the current rotation speed. The latest ignition angle is recorded as θ1.

[0198] In the process of gradually retarding the ignition advance angle from the optimal ignition angle, retarding the ignition advance angle can cause the fuel consumption to rise and the emissions to exceed the standard. In view of the requirements of the "economy" and "environmental protection" of the engine, the emission index and the fuel consumption index can be measured synchronously in the process of retarding the ignition advance angle. If the ignition advance angle is retarded to a certain angle, the emission index just reaches the target emission upper limit value or the fuel consumption index just reaches the target fuel consumption upper limit value, and if the ignition advance angle is further retarded, the emission index can exceed the standard or the fuel consumption index can exceed the standard, the ignition advance angle at this time can be determined as the latest ignition angle at which the emission index or the fuel consumption index just meets the standard under the current intake volume and the current speed of the engine, and the latest ignition angle is recorded as θ2.

[0199] In the process of determining the limit adjustment range of the ignition angle, in view of the requirements of the "economy" and "environmental protection" of the engine, the [θ0, θ2] can be used as the adjustment range of the ignition angle under the current intake volume and the current speed of the engine.

[0200] By analogy, the above operation can be repeated under different intake volumes and different speeds to obtain the adjustment range of the ignition angle under different intake volumes and different speeds, that is, the above mapping relationship table.

[0201] In the process of controlling the engine torque reduction, the current intake volume and the current speed of the engine can be obtained, and the target adjustment range of the ignition angle can be determined based on the current intake volume and the current speed.

[0202] Since the air path torque of the engine is usually fixed under the condition that the intake volume and the speed of the engine are unchanged, and the adjustment of the ignition angle usually determines the size of the fire path torque, the size of the ignition angle affects the difference between the air path torque and the fire path torque.

[0203] For example, if the ignition angle is the optimal ignition angle, the energy utilization rate is the highest at this time, and the difference between the air path torque and the fire path torque is zero. If the ignition angle is too late or too early, it can cause the combustion efficiency to decrease, so that the fire path torque is much larger than the air path torque, and thus the difference between the fire path torque and the air path torque is too large.

[0204] Therefore, the preset difference value can be determined according to the target adjustment range of the ignition angle determined above, and the absolute value of the torque difference between the fire path torque and the air path torque is controlled to be less than or equal to the preset difference value, so as to ensure that the ignition angle of the engine is in the target adjustment range.

[0205] Exemplarily, a mapping relationship between the target adjustment range of the ignition angle and the preset difference value can be established, and after the target adjustment range of the ignition angle under the current intake amount and the current rotation speed is determined, the preset difference value corresponding to the target adjustment range can be determined based on the mapping relationship.

[0206] For example, if the target adjustment range is [θ0, θ2], based on the mapping relationship, the preset difference value corresponding to the target adjustment range can be determined as 20 NM.

[0207] Further, as described above, the target torque reduction gradient can be determined based on the basic torque reduction gradient and the first target correction coefficient, and the target torque reduction gradient can include a target fire path torque reduction gradient and a target air path torque reduction gradient. In order to ensure that the torque difference between the fire path torque and the air path torque is always the preset difference value during the torque reduction process, the target fire path torque reduction gradient can be determined first, and then the target air path torque reduction gradient can be obtained by correcting the target fire path torque reduction gradient, and the fire path torque and the air path torque are controlled to reduce based on the determined target fire path torque reduction gradient and the target air path torque reduction gradient, so that the absolute value of the torque difference between the reduced fire path torque and the reduced air path torque is less than or equal to the preset difference value.

[0208] In a possible implementation, the target torque reduction gradient includes a target fire path torque reduction gradient and a target air path torque reduction gradient, and the target torque reduction gradient is determined based on the basic torque reduction gradient and the first target correction coefficient, including: multiplying the basic torque reduction gradient and the first target correction coefficient to obtain the target fire path torque reduction gradient; correcting the target fire path torque reduction gradient based on a second target correction coefficient to obtain the target air path torque reduction gradient; wherein the target fire path torque reduction gradient is greater than the target air path torque reduction gradient; and the second target correction coefficient is used to control the absolute value of the torque difference between the reduced fire path torque and the reduced air path torque to be less than or equal to the preset difference value.

[0209] It can be understood that, as described above, the basic torque reduction gradient obtained by looking up the table and the first target correction coefficient are multiplied to obtain the target fire path torque reduction gradient, and in order to ensure that the absolute value of the torque difference between the fire path torque and the air path torque is always less than or equal to the preset difference value during the torque reduction process, the target air path torque reduction gradient can be obtained by correcting the target fire path torque reduction gradient.

[0210] Exemplarily, correcting the target fire path torque reduction gradient based on the second target correction coefficient can specifically include multiplying the target fire path torque reduction gradient by the second target correction coefficient to obtain the target air path torque reduction gradient.

[0211] The second target correction coefficient is generally greater than zero. When the second target correction coefficient is less than 1, it means that the target air path torque reduction gradient is corrected to be smaller than the target fire path torque reduction gradient. When the second target correction coefficient is greater than 1, it means that the target fire path torque reduction gradient is corrected to be greater than the target fire path torque reduction gradient. When the second target correction coefficient is equal to 1, it means that the target fire path torque reduction gradient is not corrected, and the target air path torque reduction gradient is equal to the target fire path torque reduction gradient.

[0212] For example, the second target correction coefficient can be set according to actual conditions, and can be set according to the preset difference. Assuming that the preset difference is set to 20 NM, the target fire path torque reduction gradient determined based on Tables 2 and 3 is 900 NM / s, and after the fire path torque is controlled based on the target fire path torque reduction gradient, the fire path torque is reduced from 140 NM to 90 NM, and the current air path torque is 120 NM. In order to ensure that the torque difference between the reduced fire path torque and the reduced air path torque is less than or equal to 20 NM, the second target correction coefficient is determined to be 0.2, that is, the target air path torque is 180 NM / s.

[0213] It can be understood that, during the control of the torque reduction of the engine, the fire path torque of the engine will generally be reduced to zero, and the air path torque of the engine will generally have a certain reservation, that is, the air path torque will not be reduced to zero. Based on this, the speed of the fire path torque reduction of the engine is generally greater than the speed of the air path torque reduction of the engine, so as to ensure that when the air path torque of the engine is reduced to the reserved torque value, the fire path torque of the engine is exactly reduced to zero, that is, to ensure that the torque difference between the fire path torque and the air path torque during the torque reduction is always less than or equal to the preset difference. Therefore, the target fire path torque reduction gradient is generally greater than the target air path torque reduction gradient.

[0214] In some embodiments, the target air path torque reduction gradient can also be determined based on the first and second corresponding relationships, that is, the basis torque reduction gradient of the air path torque is determined based on the first corresponding relationship corresponding to the air path torque, and then the first target correction coefficient is determined based on the second corresponding relationship corresponding to the air path torque, and the product of the first target correction coefficient and the basis torque reduction gradient is determined as the target air path torque reduction gradient.

[0215] The difference is that, under the same parameters, the basis torque reduction gradient in the first corresponding relationship corresponding to the air path torque is generally smaller than the basis torque reduction gradient in the first corresponding relationship corresponding to the fire path torque, and the first target correction coefficient in the second corresponding relationship corresponding to the air path torque is generally smaller than the first target correction coefficient in the second corresponding relationship corresponding to the fire path torque, so that the target fire path torque reduction gradient is always greater than the target air path torque reduction gradient.

[0216] In the method, the target fire path torque reduction gradient and the target air path torque reduction gradient are determined, so that the fire path torque and the air path torque of the engine are both controlled to reduce torque, the second target correction coefficient is used to make the torque difference between the reduced fire path torque and the reduced air path torque less than or equal to the preset difference, so that the problem of large fuel consumption caused by the separation of the air path and the fire path during the torque reduction process is avoided, and the economy of the vehicle during the gear shifting process is improved.

[0217] Further, after the target fire path torque reduction gradient and the target air path torque reduction gradient are determined, the fire path torque and the air path torque are simultaneously controlled to reduce according to the determined target fire path torque reduction gradient and the target air path torque reduction gradient.

[0218] In a possible implementation, the target torque reduction gradient includes a target fire path torque reduction gradient and a target air path torque reduction gradient, and the target torque includes a target fire path torque and a target air path torque. The actual torque of the engine is controlled to reduce to the target torque based on the target torque reduction gradient, including: controlling the fire path torque of the engine to reduce to the target fire path torque according to the target fire path torque reduction gradient; and controlling the air path torque of the engine to reduce to the target air path torque according to the target air path torque reduction gradient during the process of controlling the fire path torque of the engine to reduce according to the target fire path torque reduction gradient, so that the absolute value of the torque difference between the reduced fire path torque and the reduced air path torque is less than or equal to a preset difference, and the ignition angle of the engine is ensured to be within the target adjustment range.

[0219] It can be understood that, since the target air path torque reduction gradient is corrected based on the target fire path torque reduction gradient, and the correction amount of the target air path torque reduction gradient is determined based on the preset difference between the expected fire path torque and the air path torque, the fire path torque is controlled to reduce according to the target fire path torque reduction gradient, and the air path torque is controlled to reduce according to the target air path torque reduction gradient, so that the air path torque and the fire path torque are both reduced, and the absolute value of the torque difference between the reduced fire path torque and the reduced air path torque is always less than or equal to the preset difference, and the ignition angle of the engine is always ensured to be within the target adjustment range.

[0220] Further, if the fire path torque cannot be reduced to the target fire path torque through the ignition angle adjustment, it indicates that the target fire path torque requested by the VCU has exceeded the torque range that can be covered by the ignition angle adjustment, and at this time, in order to continue to control the fire path torque of the engine to reduce, the engine can be controlled to be de-cylindered, so that the fire path torque of the engine is reduced to the target fire path torque.

[0221] In a possible implementation, the method further includes: if the fire path torque of the engine controlled according to the target fire path torque reduction gradient does not reach the target fire path torque, determining a target number of cylinders to be deactivated in the engine based on the target fire path torque and a target torque range of a single cylinder; the target torque range of the single cylinder is determined based on a target adjustment range of the ignition angle; and performing a deactivation process on the cylinders corresponding to the target number of cylinders to be deactivated in the engine, so that the fire path torque is reduced to the target fire path torque.

[0222] It can be understood that the vehicle controller can monitor the size relationship between the actual fire path torque and the target fire path torque after the ignition angle of the engine is adjusted in real time. If the actual fire path torque is always higher than the target fire path torque, it can be determined that the current adjusted ignition angle cannot reduce the fire path torque to the target fire path torque value. The vehicle controller can control the fire path torque of the engine to be reduced to the target fire path torque by using the deactivation request.

[0223] Further, the target torque range corresponding to the single cylinder can be determined based on the target adjustment range of the ignition angle determined above, and the target torque range represents the torque range that can be output by the ignition angle adjustment. For example, if the target adjustment range of the ignition angle is [θ0, θ2], it is determined that the output torque of the single cylinder can be adjusted to [5 NM, 20 NM] by the ignition angle adjustment.

[0224] Then, the number of working cylinders to be retained is determined according to the target fire path torque value and the target torque range of the single cylinder determined above, and the target number of cylinders to be deactivated is obtained by subtracting the number of working cylinders to be retained from the total number of cylinders of the engine.

[0225] For example, it is assumed that the target fire path torque is 5 NM, the target torque range of the single cylinder is [5 NM, 20 NM], and the engine is a 4-cylinder engine. It is indicated that the fire path torque cannot be reduced to the target fire path torque value only by adjusting the ignition angle, and the deactivation process needs to be performed. When only one cylinder works, the minimum torque value that can be reached by the cylinder is exactly equal to the target fire path torque. Therefore, it can be determined that the number of working cylinders to be retained is 1, and the target number of cylinders to be deactivated is 3.

[0226] Further, after the target number of cylinders to be deactivated is determined, the cylinders corresponding to the target number of cylinders to be deactivated in the engine can be controlled to perform the deactivation process. The deactivation process can be that fuel injection is stopped in the cylinders to be deactivated, the spark plug in the cylinders to be deactivated is controlled to stop generating the electric spark, and the intake valve and the exhaust valve in the cylinders to be deactivated are controlled to be closed. Through the above deactivation process, the cylinders can be stopped working, so that the fire path torque of the engine is reduced to the target fire path torque.

[0227] In the above method, in the case that the fire road torque cannot be reduced to the target fire road torque in the manner of reducing the fire road torque gradient through the target fire road, the target number of cylinders to be disconnected in the engine can be accurately determined based on the target fire road torque and the target torque range of a single cylinder, so as to ensure that the single-cylinder torque of the remaining cylinders after disconnection is still in the compliance range, and combustion instability caused by excessive torque reduction is avoided. Then, the cylinders corresponding to the target number of cylinders to be disconnected in the engine are disconnected, the number of effective working cylinders in the engine is reduced, the torque output of the engine is directly reduced, and finally the fire road torque is accurately reduced to the target fire road torque.

[0228] In step 204, as described above, during the switching of the driving mode of the vehicle from the series mode to the direct drive mode, the clutch is usually controlled to be opened, and in order to reduce the impact on mechanical parts and prevent the vehicle from stalling, the torque of the engine is usually controlled to be reduced to a certain value before the clutch is controlled to be opened, that is, the torque of the engine is controlled to be reduced to the target torque according to the target torque reduction gradient, and then the clutch is controlled to be opened, so as to complete the switching of the mode.

[0229] In a possible implementation, the method for switching the driving mode of the vehicle from the series mode to the direct drive mode by controlling the clutch to be in the open state comprises the following steps: controlling the clutch to be in the open state, and controlling the gear of the gearbox of the vehicle to be switched to the target gear corresponding to the direct drive mode when the clutch is in the open state; controlling the clutch to be in the closed state in the case that the rotational speed difference between the two ends of the clutch is less than or equal to a preset rotational speed difference; determining the target torque increase gradient in the case that the clutch is in the closed state; and controlling the actual torque of the engine to increase based on the target torque increase gradient, so as to switch the driving mode of the vehicle from the series mode to the direct drive mode.

[0230] It can be understood that, in the case that the air path torque is reduced to 20 NM and the fire road torque is reduced to 0 NM, it indicates that the actual torque of the engine has been reduced to 0 NM. When the torque of the front drive motor is also reduced to close to zero (for example, the absolute value of the torque of the front drive motor is less than 5 NM), the clutch of the vehicle can be controlled to be in the open state, and at this time the engine and the gearbox are disconnected.

[0231] In the case that the clutch is in the open state, the rotational speed of the front drive motor can be adjusted so that the rotational speed of the front drive motor is consistent with the current vehicle speed, and in the case that the rotational speed of the front drive motor is determined to be consistent with the current vehicle speed, the gear shifting is realized by controlling the gearbox synchronizer to shift from the neutral gear to the target gear corresponding to the direct drive mode.

[0232] After the gear switching is completed, the engine speed can be adjusted so that the engine speed is consistent with the front motor speed, i.e., the engine speed and the front motor speed are controlled to be consistent with the current vehicle speed. In the case where the engine speed is consistent with the front motor speed, i.e., the speed difference between the two ends of the clutch is less than or equal to a preset speed difference (such as zero), the clutch is controlled to be closed.

[0233] A speed sensor can be arranged at each end of the clutch to detect the speed at each end of the clutch. During the adjustment of the engine speed, the two speeds detected by the speed sensors at the two ends of the clutch can be obtained, and the difference between the two speeds can be calculated to obtain the above-mentioned speed difference.

[0234] The preset speed difference is the maximum speed difference that can exist at the two ends of the clutch when the clutch is safely and smoothly closed. When the speed difference at the two ends of the clutch is less than the preset speed difference, it can be determined that the clutch can be safely and smoothly closed at present, and the clutch can be controlled to be in a closed state at this time.

[0235] After it is determined that the clutch is in a closed state, the engine output torque can be controlled to drive the vehicle to run. Since the engine torque has been reduced to the target torque value before gear switching, the engine torque needs to be controlled to rise at this time so that the engine output torque drives the vehicle to run.

[0236] It can be understood that after the driving mode of the vehicle changes from the series mode to the direct drive mode, the power source of the vehicle changes, and the engine output power is required to drive the vehicle to run, so after the clutch is controlled to be completely closed, the engine torque needs to be gradually controlled to rise smoothly. At this time, the engine output torque is transmitted to the transmission through the closed clutch, and the power is further transmitted to the front wheels of the vehicle through the currently engaged gear of the transmission, and finally drives the vehicle to run.

[0237] In order to ensure the stability of the vehicle running, a torque rising gradient can be determined, and the engine torque is gradually increased from the target torque value according to the torque rising gradient, so as to avoid the vehicle instability caused by the excessive fluctuation of the engine torque.

[0238] In some embodiments, the vehicle demand torque can be determined based on the current accelerator opening, and the target value of the engine output torque to be increased can be determined based on the vehicle demand torque. It can be understood that the accelerator opening is changed in real time during the driving of the vehicle, and therefore the target value of the engine output torque to be increased also changes with the change of the accelerator opening.

[0239] In a possible implementation manner, the target torque increase gradient is determined by: obtaining the current engine speed, the current engine torque, the clutch pressure, the accelerator pedal opening degree, and the current vehicle speed; determining a basic torque increase gradient based on the current engine speed and the current engine torque; determining a first correction coefficient based on the current engine torque and the clutch pressure; determining a second correction coefficient based on the accelerator pedal opening degree and the current vehicle speed; and determining the target torque increase gradient based on the basic torque increase gradient, the first correction coefficient, and the second correction coefficient.

[0240] The current engine speed is the actual rotating speed of the engine. A rotating speed sensor can be arranged in the engine. After it is determined that the clutch is in the closed state, the rotating speed sensor arranged in the engine can be used to obtain the current rotating speed of the engine, and the current engine speed is obtained.

[0241] The current engine torque is the actual output torque of the engine. As described in the above embodiment, a torque sensor can be arranged in the engine. After it is determined that the clutch is in the closed state, the torque sensor arranged in the engine can be used to obtain the current torque of the engine, and the current engine torque is obtained.

[0242] The clutch pressure specifically refers to the pressure applied to both sides of the clutch when the clutch is engaged, and the unit is N. When the clutch is a hydraulic clutch, the clutch pressure can be determined based on the oil pressure of the clutch. The pressure corresponding torque can be determined based on the clutch pressure, and the unit is NM.

[0243] As described in the above embodiment, the accelerator pedal stroke can be detected, and the accelerator pedal opening degree can be determined based on the accelerator pedal stroke.

[0244] The current vehicle speed is the current speed of the vehicle. As described in the above embodiment, the rotating speed sensor can be arranged on the wheel of the vehicle, and the rotating speed sensor arranged on the wheel can be used to obtain the current wheel speed, and the current vehicle speed can be calculated based on the wheel speed and the wheel radius. Alternatively, the current vehicle speed can also be measured by using the inertial measurement unit or the global positioning system. The application does not limit the method for obtaining the current vehicle speed.

[0245] The vehicle stores a third corresponding relationship between the current engine speed, the current engine torque, and the torque increase gradient. After the above parameters are obtained, the third corresponding relationship can be searched based on the current engine speed and the current engine torque, and the basic torque increase gradient is obtained. The third corresponding relationship can be specifically as shown in Table 4.

[0246] Table 4

[0247] A / B 1000 1500 2000 3000 4000 5000 6000 -10 1200 1200 1200 1200 1200 1200 1200 20 300 300 300 500 500 500 500 40 300 300 300 500 500 500 500 50 300 300 300 500 500 500 500 80 300 300 300 500 500 500 500 100 300 300 300 500 500 500 500

[0248] In Table 4, A is the current torque of the engine, in units of NM, and B is the current speed of the engine, in units of rpm. In the third correspondence relationship shown in Table 4, when the current torque of the engine is negative, the torque rising gradient is large, all being 1200 NM / s. When the current torque of the engine is positive, the torque rising gradient is small, all being in the range of 300 NM / s to 500 NM / s as shown in Table 4. Moreover, in the third correspondence relationship, when the current torque of the engine is positive, the torque rising gradient increases with the increase of the current speed of the engine at a certain current torque of the engine.

[0249] It can be understood that when the current torque of the engine is negative, it indicates that the engine is currently in a deceleration state, and the engine is prone to speed drop due to negative torque, thereby causing the engine to stop. After the clutch is closed, the engine needs to output torque to drive the vehicle, in order to avoid engine stop and make the engine quickly output torque, the torque rising of the engine can be controlled based on a large torque rising gradient. Therefore, in the third correspondence relationship, when the torque of the engine is negative, the torque rising gradient is large, all being 1200 NM / s.

[0250] When the current torque of the engine is positive, it indicates that the engine is currently outputting normal torque, and the engine has no risk of stopping. At this time, the torque rising of the engine needs to be controlled based on a small torque rising gradient to ensure the smoothness of the vehicle. Therefore, in the third correspondence relationship, when the torque of the engine is positive, the torque rising gradient is small, all being in the range of 300 NM / s to 500 NM / s as shown in Table 4.

[0251] When the engine is in the medium-high speed interval, the intake inertia is enhanced and cooperates with the optimization of valve timing to promote the "nonlinear improvement of intake efficiency", superimposed with the improvement of combustion efficiency at this speed, the reduction of mechanical loss ratio, the unit speed rising corresponding to the intake amount increment and effective torque increment are significantly accelerated. Therefore, under this working condition, the torque of the engine can be controlled to rise rapidly based on a larger torque rising gradient. Therefore, in the third correspondence relationship, when the torque of the engine is positive, the torque rising gradient increases with the increase of the speed of the engine at a certain torque of the engine.

[0252] For example, the current speed of the engine obtained is 2000 rpm, and the current torque of the engine is 20 NM. Based on 2000 rpm and 20 NM, the above Table 4 can be searched to obtain that the basic torque rising gradient is 300 NM / s.

[0253] The vehicle stores a fourth correspondence relationship between the first correction coefficient and the current torque of the engine and the torque corresponding to the pressure of the clutch. After obtaining the above-mentioned multiple parameters, the first correction coefficient can be obtained by looking up the fourth correspondence relationship based on the current torque of the engine and the torque corresponding to the pressure of the clutch. The fourth correspondence relationship is specifically shown in Table 5 as follows:

[0254] Table 5

[0255] C / A 0 10 30 60 80 100 140 0 0.5 0.45 0.4 0.35 0.3 0.25 0.2 10 1 0.5 0.45 0.4 0.35 0.3 0.25 30 1 1 0.5 0.45 0.4 0.35 0.3 60 1 1 1 0.5 0.45 0.4 0.35 80 1 1 1 1 0.5 0.45 0.4 100 1 1 1 1 1 0.5 0.45 140 1 1 1 1 1 1 0.5

[0256] In Table 5, A is the current torque of the engine, and the unit is NM, and C is the torque corresponding to the pressure of the clutch, and the unit is NM. In the fourth correspondence relationship shown in Table 5, when the current torque of the engine is less than the torque corresponding to the pressure of the clutch, the first correction coefficient is 1, and at this time, the basic torque increase gradient is not corrected. When the current torque of the engine is greater than or equal to the torque corresponding to the pressure of the clutch, the first correction coefficient is less than 1, and at this time, the basic torque increase gradient is reduced based on the first correction coefficient. That is, at this time, the engine torque rising speed is slow. When the current torque of the engine is greater than or equal to the torque corresponding to the pressure of the clutch, the torque corresponding to the pressure of the clutch is fixed, and as the current torque of the engine increases, the first correction coefficient tends to decrease. The basic torque increase gradient will be reduced to a smaller gradient.

[0257] It can be understood that the current torque of the engine is transmitted to the gearbox through the clutch. When the torque corresponding to the pressure of the clutch is greater than the current torque of the engine, the current torque of the engine can be completely transmitted to the gearbox through the clutch, and the engine torque based on the gradient increase can also be safely transmitted to the gearbox through the clutch at this time, and the basic torque increase gradient can not be corrected. Therefore, in the fourth correspondence relationship, when the current torque of the engine is less than the torque corresponding to the pressure of the clutch, the first correction coefficient is 1.

[0258] When the current torque of the engine is greater than or equal to the torque corresponding to the pressure of the clutch, after the engine torque is controlled based on the basic torque increase gradient, a larger part of the engine torque will exceed the torque corresponding to the pressure of the clutch, and at this time, the clutch has the risk of slipping. In order to avoid the clutch slipping caused by the sudden increase of the engine output torque, the torque increase gradient needs to be more moderate. Therefore, in the fourth correspondence relationship, when the current torque of the engine is greater than or equal to the torque corresponding to the pressure of the clutch, the first correction coefficient is less than 1, and at this time, the basic torque increase gradient is reduced.

[0259] When the current torque of the engine is greater than or equal to the torque corresponding to the pressure of the clutch, the greater the torque corresponding to the pressure of the clutch, the higher the risk of clutch slip, and the greater the force with which the torque gradient should be flattened to make the torque of the engine rise more slowly. Therefore, in the fourth correspondence, when the current torque of the engine is greater than or equal to the torque corresponding to the pressure of the clutch, the first correction coefficient decreases with the increase of the current torque of the engine under the condition that the torque corresponding to the pressure of the clutch is fixed. The basic torque gradient will be reduced to a smaller gradient.

[0260] For example, the current torque of the engine obtained is 20 NM, and the torque corresponding to the pressure of the clutch is 20 NM. Based on the current torque of the engine being 20 NM and the torque corresponding to the pressure of the clutch being 20 NM, the first correction coefficient can be obtained by looking up Table 5 above, which is 0.5.

[0261] The vehicle stores a fifth correspondence between the accelerator pedal opening degree and the current vehicle speed and the second correction coefficient. After obtaining the above-mentioned various parameters, the second correction coefficient can be obtained by looking up the fifth correspondence based on the accelerator pedal opening degree and the current vehicle speed. The fifth correspondence is specifically shown in Table 6 below:

[0262] Table 6

[0263] D / W 0 20 40 60 80 100 0 0.5 0.6 0.8 1 1 1 20 0.5 0.6 0.8 1 1 1 50 0.7 0.8 0.9 1 1.1 1.1 60 0.8 0.9 1 1.1 1.2 1.2 80 1 1 1 1.2 1.2 1.2 100 1 1 1 1.3 1.3 1.3 140 1 1 1 1.3 1.3 1.3

[0264] In Table 6, W is the accelerator pedal opening degree, and the unit is %, and D is the current vehicle speed, and the unit is kph. In the fifth correspondence shown in Table 7, when the accelerator pedal opening degree is fixed, the second correction coefficient increases with the increase of the current vehicle speed. When the current vehicle speed is fixed, the second correction coefficient increases with the increase of the accelerator pedal opening degree. Specifically, when the accelerator pedal opening degree is less than a third opening degree (for example, 40% in Table 6) and the current vehicle speed is less than a first vehicle speed (for example, 60 kph in Table 6), the second correction coefficient is less than 1. When the accelerator pedal opening degree is greater than the third opening degree (for example, 40% in Table 6) and the current vehicle speed is greater than a second vehicle speed (for example, 50 kph in Table 6), the second correction coefficient is greater than 1.

[0265] It can be understood that the greater the opening degree of the accelerator pedal, the greater the power demand of the driver, or the greater the current vehicle speed, the greater the power demand of the driver. The greater the power demand, the faster the vehicle needs to control the engine output torque to meet the power demand. Therefore, in the fifth correspondence, when the accelerator pedal opening degree is fixed, the second correction coefficient increases with the increase of the current vehicle speed. When the current vehicle speed is fixed, the second correction coefficient increases with the increase of the accelerator pedal opening degree.

[0266] When the accelerator pedal opening is less than the third opening and the current vehicle speed is less than the first vehicle speed, the current power demand of the vehicle is small, at this time the engine torque rise can be controlled based on a small gradient, therefore in the fifth corresponding relationship, when the accelerator pedal opening is less than the third opening and the current vehicle speed is less than the first vehicle speed, the second correction coefficient is less than 1, used to reduce the basic torque rise gradient.

[0267] When the accelerator pedal opening is greater than the third opening and the current vehicle speed is greater than the second vehicle speed, the current power demand of the vehicle is large, at this time the engine torque rise needs to be controlled based on a large gradient to meet the power demand of the driver. Therefore, in the fifth corresponding relationship, when the accelerator pedal opening is greater than the third opening and the current vehicle speed is greater than the second vehicle speed, the second correction coefficient is greater than 1, used to enlarge the basic torque rise gradient.

[0268] For example, the obtained accelerator pedal opening is 60%, and the current vehicle speed of the vehicle is 100kph, then based on the accelerator pedal opening 60% and the current vehicle speed 100kph, the second correction coefficient can be obtained from the above table 6, which is 1.3.

[0269] After obtaining the basic torque rise gradient, the first correction coefficient and the second correction coefficient, the basic torque rise gradient is multiplied by the first correction coefficient and the second correction coefficient in turn to obtain the target torque rise gradient. As in the above example, the determined basic torque rise gradient is 300NM / s, the first correction coefficient is 0.5, and the second correction coefficient is 1.3, then the target torque rise gradient = 300*0.5*1.3 = 195NM / s.

[0270] In some embodiments, the engine includes two parts of fire path torque and air path torque, and the target torque rise gradient also includes two parts of fire path torque rise gradient and air path torque rise gradient. The fire path torque rise gradient and the air path torque rise gradient need to be determined respectively, the fire path torque rise gradient is used to control the rise of the fire path torque of the engine, and the air path torque rise gradient is used to control the rise of the air path torque of the engine.

[0271] The process of determining the target torque rise gradient based on table 4, table 5 and table 6 in the above example can be the process of determining the fire path torque rise gradient. The process of determining the air path torque rise gradient is the same as the process of determining the fire path torque rise gradient, that is, the basic torque rise gradient of the air path torque is obtained based on the current torque of the engine and the current torque of the engine, the first correction coefficient is determined based on the current torque of the engine and the pressure of the clutch, and the second correction coefficient is determined based on the accelerator pedal opening and the current vehicle speed. The basic torque rise gradient of the air path torque is multiplied by the first correction coefficient and the second correction coefficient in turn to obtain the air path torque rise gradient.

[0272] The difference is that when determining the air path torque increase gradient, a sixth corresponding relationship is looked up based on the current engine torque and the current engine torque to obtain a basic increase gradient. The sixth corresponding relationship is similar to the third corresponding relationship, and the calibration value of the air path torque increase gradient in the sixth corresponding relationship can be different from the calibration value of the fire path torque increase gradient in the third corresponding relationship. The air path torque increase gradient should be calibrated to ensure that the air path torque increase gradient is less than or equal to the fire path torque increase gradient.

[0273] It can be understood that, because the fire path torque usually decreases to zero during torque reduction, and there is a part of the reserved torque of the air path torque, the fire path torque usually needs to start increasing from a lower value during the torque increase process. In order to ensure that the air and fire path torques increase synchronously and further ensure the smoothness of the torque increase process, the fire path torque increase gradient can be set to be greater than the air path torque increase gradient.

[0274] In some embodiments, when determining the air path torque increase gradient, the corresponding relationship of the first correction coefficient and the second correction coefficient can be the same as that of looking up the first correction coefficient and the second correction coefficient when determining the torque increase gradient.

[0275] In some embodiments, similar to the torque reduction process, during the process of controlling the actual torque of the engine to increase based on the target increase gradient, it is usually also necessary to ensure that the ignition angle of the engine is always within the target adjustment range.

[0276] For example, in the above-mentioned embodiments, it is required to keep the ignition angle within the target adjustment range [θ0, θ2], and in this embodiment, it is also required to keep the ignition angle within the target adjustment range [θ0, θ2], and in order to further ensure the smoothness of the torque increase process, it is also required in this embodiment to control the ignition angle to deviate towards θ0 as much as possible, that is, during the process of controlling the actual torque of the engine to increase based on the target increase gradient, the torque difference between the engine fire path torque and the air path torque is controlled to be as close to zero as possible.

[0277] In some embodiments, during the process of controlling the actual torque of the engine to increase based on the target increase gradient, when the target air path torque, the target fire path torque, and the actual torque of the engine are equal, the vehicle controller can control the release state of the ignition angle to reset, that is, control the ignition angle to return to the optimal ignition angle.

[0278] It can be understood that, as described above, during the process of controlling the actual torque of the engine to increase based on the target increase gradient, the ignition angle is usually kept within the target adjustment range [θ0, θ2], and in the case where the target air path torque, the target fire path torque, and the actual torque of the engine are equal, it usually means that the torque increase target is achieved and the air and fire path torques are synchronized, at this time, the ignition angle no longer needs to be controlled to release, and therefore the ignition angle can be returned to the initial state, that is, the ignition angle is controlled to return to the optimal ignition angle.

[0279] In the above method, after the clutch is in the open state, the gear position of the gearbox is controlled to switch to the target gear position corresponding to the direct drive mode, which can establish the mechanical transmission basis in the direct drive mode in advance, prepare for subsequent power path switching, and facilitate subsequent precise control of the vehicle in the direct drive mode. Moreover, when the speed difference between the two ends of the clutch is less than or equal to the preset speed difference, the clutch is controlled to be in a closed state, and the mechanical impact during engagement can be eliminated by controlling the speed synchronization of the two ends of the clutch, thereby ensuring that the clutch can be safely and smoothly closed, and avoiding gear shifting jerk or component wear caused by excessive speed difference. In the case where the clutch is in the closed state, the actual torque of the engine is controlled to increase based on the target torque gradient, so that the engine power is smoothly transmitted to the wheels through the engaged clutch and the engaged gear of the gearbox, so that the driving mode of the vehicle is switched from the series mode to the direct drive mode, and the power is not interrupted during the switching process.

[0280] Figure 4 FIG. 1 is a structural schematic diagram of a mode switching device provided by an embodiment of the present application.

[0281] For example, as shown in FIG. 4, the device 400 includes: Figure 4

[0282] The first determination module 401 is configured to, in a case where a control instruction for switching the driving mode of the vehicle from the series mode to the direct drive mode is received, determine the discharge power of the power battery of the vehicle, the vehicle driving power of the vehicle, and the power generation power of the target motor of the vehicle.

[0283] The second determination module 402 is configured to determine a target interval in which the vehicle driving power is located based on the discharge power of the power battery, the vehicle driving power, and the power generation power of the target motor, and determine a target torque gradient corresponding to the target interval.

[0284] The first control module 403 is configured to control the actual torque of the engine to decrease to a target torque based on the target torque gradient.

[0285] The second control module 404 is configured to, in a case where the actual torque of the engine is equal to the target torque, control the clutch to be in an open state, so that the driving mode of the vehicle is switched from the series mode to the direct drive mode.

[0286] ​In a possible implementation, the second determining module is specifically configured to: in a case where the driving power of the vehicle is less than or equal to the discharging power of the power battery, determine that the target interval is the first interval, and determine the first torque reduction gradient corresponding to the first interval as the target torque reduction gradient; in a case where the driving power of the vehicle is greater than the discharging power of the power battery and less than or equal to the sum of the discharging power of the power battery and the power generation power of the target motor, determine that the target interval is the second interval, and determine the second torque reduction gradient corresponding to the second interval as the target torque reduction gradient; the first torque reduction gradient is greater than the second torque reduction gradient.

[0287] In a possible implementation, the apparatus further includes a target torque reduction gradient determining module, which is specifically configured to: obtain an original air path torque request value of the engine and a current opening degree of an accelerator pedal of the vehicle; calculate a current power difference between the driving power of the vehicle and the discharging power of the power battery; and determine the target torque reduction gradient based on the current power difference, the original air path torque request value, and the current opening degree of the accelerator pedal.

[0288] In a possible implementation, the target torque reduction gradient determining module is further specifically configured to: determine a basic torque reduction gradient corresponding to the current power difference and the original air path torque request value based on a first corresponding relationship corresponding to the target interval; the first corresponding relationship is a corresponding relationship between the two parameters of the power difference and the air path torque request value and the basic torque reduction gradient; the power difference is a difference between the driving power of the vehicle and the discharging power of the power battery; determine a first target correction coefficient corresponding to the current power difference and the current opening degree of the accelerator pedal based on a second corresponding relationship corresponding to the target interval; the second corresponding relationship is a corresponding relationship between the two parameters of the power difference and the opening degree of the accelerator pedal and the correction coefficient; and determine the target torque reduction gradient based on the basic torque reduction gradient and the first target correction coefficient.

[0289] In a possible implementation, the target torque reduction gradient includes a target fire path torque reduction gradient and a target air path torque reduction gradient, and the target torque reduction gradient determining module is further specifically configured to: multiply the basic torque reduction gradient and the first target correction coefficient to obtain the target fire path torque reduction gradient; and correct the target fire path torque reduction gradient based on a second target correction coefficient to obtain the target air path torque reduction gradient; the target fire path torque reduction gradient is greater than the target air path torque reduction gradient; and the second target correction coefficient is used to control an absolute value of a torque difference between the reduced fire path torque and the reduced air path torque to be less than or equal to a preset difference value.

[0290] Optionally, the target torque includes a target fire path torque and a target air path torque, and the device further includes a target torque determination module, which is specifically configured to: determine an original air path torque request value based on the driver demand torque, the target front-rear axle torque distribution ratio, and the actual torque of the target motor; determine the target fire path torque based on the original air path torque request value, the shift intervention torque, and the engine fire path speed control torque; and determine the target air path torque based on the original air path torque request value, the engine air path torque reservation, the engine air path speed control torque reservation, and the target fire path torque.

[0291] In a possible implementation, the target torque reduction gradient includes a target fire path torque reduction gradient and a target air path torque reduction gradient, and the target torque includes a target fire path torque and a target air path torque, and the first control module is specifically configured to: control the fire path torque of the engine to decrease to the target fire path torque according to the target fire path torque reduction gradient; and control the air path torque of the engine to decrease to the target air path torque according to the target air path torque reduction gradient in the process of controlling the fire path torque of the engine to decrease according to the target fire path torque reduction gradient, so as to achieve that an absolute value of a torque difference between the reduced fire path torque and the reduced air path torque is less than or equal to a preset difference value, and ensure that the ignition angle of the engine is within the target adjustment range.

[0292] Optionally, the device further includes a cylinder cut-off control module, which is specifically configured to: if the fire path torque of the engine after being controlled to decrease according to the target fire path torque reduction gradient does not reach the target fire path torque, determine a target number of cylinders to be cut off in the engine based on the target fire path torque and a target torque range of a single cylinder, wherein the target torque range of the single cylinder is determined based on the target adjustment range of the ignition angle; and perform cylinder cut-off processing on the cylinders corresponding to the target number of cylinders to be cut off in the engine, so as to decrease the fire path torque to the target fire path torque.

[0293] In a possible implementation, the second control module is specifically configured to: control the clutch to be in an open state, and control the gear of the gearbox of the vehicle to switch to a target gear corresponding to a direct drive mode when the clutch is in the open state; control the clutch to be in a closed state when a speed difference between two ends of the clutch is less than or equal to a preset speed difference; and determine a target torque increase gradient when the clutch is in the closed state, and control the actual torque of the engine to increase based on the target torque increase gradient, so as to switch the driving mode of the vehicle from a series mode to the direct drive mode.

[0294] In a possible implementation, the second control module includes a determination unit, which is specifically configured to: acquire a current speed of the engine, a current torque of the engine, a pressure of the clutch, an accelerator pedal opening degree of the vehicle, and a current speed of the vehicle; determine a basic torque increase gradient based on the current speed of the engine and the current torque of the engine; determine a first correction coefficient based on the current torque of the engine and the pressure of the clutch; determine a second correction coefficient based on the accelerator pedal opening degree and the current speed; and determine a target torque increase gradient based on the basic torque increase gradient, the first correction coefficient, and the second correction coefficient.

[0295] Figure 5 is a structural schematic diagram of a vehicle provided in an embodiment of the present application.

[0296] As shown in Figure 5 the vehicle 500 includes a memory 501 and a processor 502, wherein the memory 501 stores executable program code 5011, and the processor 502 is configured to invoke and execute the executable program code 5011 to perform a mode switching method.

[0297] In addition, an apparatus provided in an embodiment of the present application can include a memory and a processor, wherein the memory stores executable program code, and the processor is configured to invoke and execute the executable program code to perform a mode switching method provided in an embodiment of the present application.

[0298] The embodiment can divide the apparatus into functional modules according to the above method examples, for example, corresponding to each functional module, or two or more functions can be integrated into one processing module, and the integrated module can be implemented in the form of hardware. It should be noted that the division of modules in the embodiment is illustrative, and is only a logical function division, and another division mode can be used in actual implementation.

[0299] In the case of dividing each functional module corresponding to each function, the apparatus can further include a first determination module, a second determination module, a first control module, and a second control module, etc. It should be noted that all related contents of each step involved in the above method embodiments can be referred to the function description of the corresponding functional module, and will not be repeated here.

[0300] It should be understood that the apparatus provided in the embodiment is used to perform the above mode switching method, and thus can achieve the same effect as the above implementation method.

[0301] In the case of using an integrated unit, the apparatus can include a processing module and a storage module. When the apparatus is applied to a vehicle, the processing module can be used to control and manage the actions of the vehicle. The storage module can be used to support the vehicle to execute related program codes and data, etc.

[0302] The processing module can be a processor or a controller, which can implement or execute various exemplary logical blocks, modules, and circuits shown in connection with the disclosure of the present application. The processor can also be a combination of computing functions, such as one or more microprocessor combinations, digital signal processing (DSP) and microprocessor combinations, etc. The storage module can be a memory.

[0303] In addition, the device provided by the embodiments of the present application can be a chip, a component or a module, and the chip can include a processor and a memory connected thereto. The memory is used to store instructions, and when the processor calls and executes the instructions, the chip can execute the mode switching method provided by the above embodiments.

[0304] The embodiments also provide a computer-readable storage medium having computer program codes stored therein, and when the computer program codes are run on a computer, the computer is caused to execute the above related method steps to implement the mode switching method provided by the above embodiments.

[0305] The embodiments also provide a computer program product, and when the computer program product is run on a computer, the computer is caused to execute the above related steps to implement the mode switching method provided by the above embodiments.

[0306] The device, computer-readable storage medium, computer program product or chip provided by the embodiments are used to execute the corresponding method provided above, so the beneficial effects achieved thereby can refer to the beneficial effects of the corresponding method provided above, which will not be repeated here.

[0307] Through the above description of the embodiments, those skilled in the art can understand that, for the convenience and brevity of description, only the above division of functional modules is taken as an example for illustration. In actual application, the above functions can be completed by different functional modules according to needs, i.e. the internal structure of the device is divided into different functional modules to complete all or part of the above described functions.

[0308] In the embodiments of the present disclosure, it should be understood that the disclosed apparatus and method can be implemented in other ways. For example, the apparatus embodiments described above are merely schematic, and the division of the modules or units is merely a logical function division. In actual implementation, another division manner can be adopted, for example, a plurality of units or components can be combined or integrated into another apparatus, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, apparatuses or units, and can be electrical, mechanical or in other forms.

[0309] The above merely describes specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present disclosure, which should be covered by the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A mode switching method, characterized by, The method comprises: In the case of receiving a control instruction for switching the driving mode of the vehicle from the series mode to the direct drive mode, determining the discharge power of the power battery of the vehicle, the vehicle driving power of the vehicle and the power generation power of the target motor of the vehicle; Based on the discharge power of the power battery, the vehicle driving power and the power generation power of the target motor, determining the target interval in which the vehicle driving power is located, and determining the target torque reduction gradient corresponding to the target interval; Based on the target torque reduction gradient, controlling the actual torque of the engine to reduce to the target torque; In the case that the actual torque of the engine is equal to the target torque, controlling the clutch to be in the open state, so that the driving mode of the vehicle is switched from the series mode to the direct drive mode.

2. The method of claim 1, wherein, The target interval in which the vehicle driving power is located is determined based on the discharge power of the power battery, the vehicle driving power and the power generation power of the target motor, and the target torque reduction gradient corresponding to the target interval is determined, comprising: In the case that the vehicle driving power is less than or equal to the discharge power of the power battery, the target interval is determined as the first interval, and the first torque reduction gradient corresponding to the first interval is determined as the target torque reduction gradient; In the case that the vehicle driving power is greater than the discharge power of the power battery and less than or equal to the sum of the discharge power of the power battery and the power generation power of the target motor, the target interval is determined as the second interval, and the second torque reduction gradient corresponding to the second interval is determined as the target torque reduction gradient; wherein the first torque reduction gradient is greater than the second torque reduction gradient.

3. The method of claim 1, wherein, The target torque reduction gradient is determined by: Obtaining the original gas path torque request value of the engine and the current opening degree of the accelerator pedal of the vehicle; Calculating the current power difference value between the vehicle driving power and the discharge power of the power battery; Based on the current power difference value, the original gas path torque request value and the current opening degree of the accelerator pedal, the target torque reduction gradient is determined.

4. The method of claim 3, wherein, The target torque reduction gradient is determined based on the current power difference value, the original gas path torque request value and the current opening degree of the accelerator pedal, comprising: Based on the first corresponding relationship corresponding to the target interval, the basic torque reduction gradient corresponding to the current power difference value and the original gas path torque request value is determined; wherein the first corresponding relationship is the corresponding relationship between the two parameters of power difference value and gas path torque request value and the basic torque reduction gradient; the power difference value is the difference between the vehicle driving power and the discharge power of the power battery; Based on the second corresponding relationship corresponding to the target interval, the first target correction coefficient corresponding to the current power difference value and the current opening degree of the accelerator pedal is determined; wherein the second corresponding relationship is the corresponding relationship between the two parameters of power difference value and accelerator pedal opening degree and correction coefficient; Based on the basic torque reduction gradient and the first target correction coefficient, the target torque reduction gradient is determined.

5. The method of claim 4, wherein, The target torque reduction gradient includes a target fire path torque reduction gradient and a target air path torque reduction gradient, and the target torque is determined based on the basic torque reduction gradient and the first target correction coefficient, including: The basic torque reduction gradient and the first target correction coefficient are multiplied to obtain the target fire path torque reduction gradient; The target air path torque reduction gradient is obtained by correcting the target fire path torque reduction gradient based on a second target correction coefficient; wherein the target fire path torque reduction gradient is greater than the target air path torque reduction gradient; and the second target correction coefficient is used to control the absolute value of the torque difference between the reduced fire path torque and the reduced air path torque to be less than or equal to a preset difference.

6. The method according to any one of claims 1 to 5, characterized in that, The target torque includes a target fire path torque and a target air path torque, and the target torque is determined by the following method: The original air path torque request value is determined based on the driver demand torque, the target front and rear axle torque distribution ratio, and the actual torque of the target motor; The target fire path torque is determined based on the original air path torque request value, the shift intervention torque, and the engine fire path speed control torque; The target air path torque is determined based on the original air path torque request value, the engine air path torque reservation, the engine air path speed control torque reservation, and the target fire path torque.

7. The method according to any one of claims 1 to 5, characterized in that, The target torque includes a target fire path torque and a target air path torque, and the target torque is determined by the following method: The target torque includes a target fire path torque and a target air path torque, and the target torque is determined by the following method: The target torque includes a target fire path torque and a target air path torque, and the target torque is determined by the following method:

8. The method of claim 7, wherein, The target torque includes a target fire path torque and a target air path torque, and the target torque is determined by the following method: The target torque includes a target fire path torque and a target air path torque, and the target torque is determined by the following method: The method further includes:

9. The method according to any one of claims 1 to 5, characterized in that, If the fire path torque after the control of the engine according to the target fire path torque reduction gradient does not reach the target fire path torque, the target number of cylinder cut-offs in the engine is determined based on the target fire path torque and the target torque range of a single cylinder; wherein the target torque range of a single cylinder is determined based on the target adjustment range of the ignition angle; The cylinders corresponding to the target number of cylinder cut-offs in the engine are subjected to cylinder cut-off processing to reduce the fire path torque to the target fire path torque. The control of the clutch in the open state to switch the driving mode of the vehicle from the series mode to the direct drive mode includes: The clutch is controlled in the open state, and the gear of the transmission of the vehicle is switched to the target gear corresponding to the direct drive mode when the clutch is in the open state; In the case where the speed difference between the two ends of the clutch is less than or equal to a preset speed difference, the clutch is controlled in the closed state. In a case where the clutch is in a closed state, a target torque increase gradient is determined; An actual torque increase of the engine is controlled based on the target torque increase gradient, so that a driving mode of the vehicle is switched from the series mode to the direct drive mode.

10. The method of claim 9, wherein, The determining of the target torque increase gradient comprises: A current speed of the engine, a current torque of the engine, a pressure of the clutch, an accelerator pedal opening degree of the vehicle, and a current speed of the vehicle are acquired; A base torque increase gradient is determined based on the current speed of the engine and the current torque of the engine; A first correction coefficient is determined based on the current torque of the engine and the pressure of the clutch; A second correction coefficient is determined based on the accelerator pedal opening degree and the current speed of the vehicle; The target torque increase gradient is determined based on the base torque increase gradient, the first correction coefficient, and the second correction coefficient.

11. A vehicle characterized by comprising: The vehicle comprises: a memory for storing executable program codes; a processor for calling and running the executable program codes from the memory, so that the vehicle executes the method according to any one of claims 1 to 10.

12. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, when the computer program is executed, the method according to any one of claims 1 to 10 is realized. The computer readable storage medium stores a computer program, when the computer program is executed, the method according to any one of claims 1 to 10 is realized.

Images