CN118030826A - Gear shifting control method and system for AMT gearbox and new energy vehicle - Google Patents

Gear shifting control method and system for AMT gearbox and new energy vehicle Download PDF

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Publication number
CN118030826A
CN118030826A CN202410049616.1A CN202410049616A CN118030826A CN 118030826 A CN118030826 A CN 118030826A CN 202410049616 A CN202410049616 A CN 202410049616A CN 118030826 A CN118030826 A CN 118030826A
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China
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gear
motor
vehicle
curve
gearbox
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刘宗剑
黄琨
赵狄
位跃辉
彭金雷
王小娟
孟小培
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Yutong Bus Co Ltd
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Yutong Bus Co Ltd
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Priority to CN202410049616.1A priority Critical patent/CN118030826A/en
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/72—Electric energy management in electromobility

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Abstract

The invention belongs to the technical field of vehicle transmission, and particularly relates to an AMT gearbox gear shifting control method and system and a new energy vehicle. The gear shifting control method of the AMT gearbox comprises the following steps: detecting the temperature of a motor and/or a motor controller, and when the temperature of the motor exceeds a first set threshold value or the temperature of the motor controller exceeds a second set threshold value, controlling gear shifting of a gearbox by adopting a first gear shifting curve, wherein the speed of the vehicle is increased under the same accelerator opening degree when the first gear shifting curve is compared with a basic gear shifting curve; the basic gear shifting curve is adopted when the temperature of the motor is in a normal working temperature range of the motor and the temperature of the motor controller is in a normal working temperature range of the motor controller. The motor or the motor controller is enabled to be in advance downshifted or in delay upshift when being too high, the gearbox is guaranteed to work in a lower gear, the torque load of the motor is reduced, and therefore the risk of too high temperature of the motor or the motor controller is reduced.

Description

Gear shifting control method and system for AMT gearbox and new energy vehicle
Technical Field
The invention belongs to the technical field of vehicle transmission, and particularly relates to an AMT gearbox gear shifting control method and system and a new energy vehicle.
Background
An Automated Mechanical Transmission (AMT) performs an automatic shift strategy, which can reduce driving operation load and improve vehicle operation efficiency compared to a Manual Transmission (MT). In the conventional gear shift control method of the multi-gear AMT gearbox mounted on the new energy vehicle, gear shift is performed based on a gear shift curve of an accelerator opening degree and a vehicle speed, the gear shift curve is generally designed based on conditions such as a motor rotation speed torque characteristic, a motor high-efficiency interval, a driver operation characteristic and the like, as shown in fig. 1, the gear shift curve is generally a set of curves which are diffused to the right upper corner in an accelerator and vehicle speed coordinate axis, for example, a 2-gear up-3-gear curve is a 2-gear up-3-gear curve, the vehicle speed is increased along with the increase of the accelerator opening degree, and the 3-gear up-4-gear curve is on the right side of the 2-gear up-3-gear curve. Because the vehicle has the extreme working condition of continuously ascending or continuously descending in the actual running process, if the temperature of the motor or the motor controller is higher at this moment, the motor continuously works at high torque, namely the torque is above rated torque, the temperature of the motor or the motor controller can be further increased, the temperature of the motor or the motor controller is overhigh, the service life of the motor or the motor controller is shortened, and even the motor or the motor controller is burnt out when serious, so that the vehicle cannot normally run, and the safety risk is caused.
Disclosure of Invention
The invention aims to provide an AMT gearbox gear-shifting control method and system and a new energy vehicle, which are used for solving the problem that the temperature of a motor or a motor controller is too high when the vehicle is in an extreme working condition of continuous ascending or continuous descending by the existing AMT gearbox gear-shifting control method.
The invention provides a gear shifting control method of an AMT (automated mechanical transmission) gear shifting box, which is used for solving the technical problems, detecting the temperature of a motor and/or a motor controller, and controlling gear shifting of the gear shifting box by adopting a first gear shifting curve when the temperature of the motor exceeds a first set threshold value or the temperature of the motor controller exceeds a second set threshold value, wherein the first gear shifting curve is compared with a basic gear shifting curve, and the speed of the vehicle is increased under the same accelerator opening; the basic gear shifting curve is adopted when the temperature of the motor is in a normal working temperature range of the motor and the temperature of the motor controller is in a normal working temperature range of the motor controller.
Further, the first shift curve is derived from a base shift curve translating a set point in a direction of increasing speed.
Further, the basic shift curves among different gears are different in set value of translation in the direction of speed increase, and the calculation formula of the set value is as follows:
Wherein Deltaux is a set value of rightward translation of a basic gear shifting curve of the gear x and the gear x+1 of the gearbox, n max is the highest rotating speed of the motor, ux is the highest vehicle speed in the basic gear shifting curve of the gear x and the gear x+1, R is the radius of a tire, i gx is the gear x speed ratio of the gearbox, and i f is the main speed reduction ratio.
Further, when the temperature of the motor is higher than the normal working temperature of the motor and lower than a first set threshold value, or the temperature of the motor controller is higher than the normal working temperature of the motor controller and lower than a second set threshold value, a second gear shifting curve is adopted to control gear shifting of the gearbox; the second gear shifting curve is obtained by linear interpolation between the basic gear shifting curve and the first gear shifting curve.
Further, when the gear shifting of the gearbox is controlled by adopting a corresponding gear shifting curve, whether the vehicle meets any gear locking strategy is further judged; the lock and gear strategy comprises the following steps:
Calculating the running resistance of the vehicle and the maximum driving resistance after upshifting when the upshifting condition is met based on a gear locking strategy of the dynamic gradient and the dynamic load, and executing gear locking if the maximum driving resistance is smaller than the running resistance;
Executing a lock-up when the vehicle anti-lock system is activated or in a slip state based on a lock-up strategy of an extreme state of the vehicle;
and executing gear locking when the vehicle brake feedback torque is larger than the second set value, the sliding feedback torque is larger than the third set value or the vehicle is braked and no energy feedback exists based on a gear locking strategy of braking and energy feedback.
Further, after the gear locking strategy is met and the gear locking is executed, if the vehicle is judged to be stopped, the gear locking is released.
Further, if the motor rotation speed is larger than the first set rotation speed value, and overspeed upshift protection strategy is executed when overspeed risk exists, and gear box upshift is controlled.
Further, the calculation formula of the running resistance of the vehicle is:
Wherein F x is running resistance, m is dynamic load of the vehicle, g is gravitational acceleration, F is rolling resistance coefficient, i is dynamic gradient value, C D is air resistance coefficient, A is windward area of the vehicle, ρ is air density, v is vehicle speed, t is time, and δ is conversion coefficient of rotational mass of the vehicle.
The beneficial effects of the technical scheme are as follows: when the temperature of the motor or the motor controller is higher, the gear shifting of the gearbox is controlled by adopting the corrected first gear shifting curve, so that the vehicle is shifted down in advance or shifted up in a delayed manner, the gearbox is ensured to work in a lower gear, the torque load of the motor is reduced, the further temperature rise of the motor or the motor controller is avoided, and the problem that the temperature of the motor or the motor controller is too high when the vehicle is in an extreme working condition of continuous ascending or continuous descending by the existing AMT gearbox gear shifting control method is solved.
The invention provides an AMT gearbox gear-shifting control system for solving the technical problems, which comprises a controller, a motor and an AMT gearbox which are in transmission connection, wherein the controller is used for executing the AMT gearbox gear-shifting control method to control the motor and the AMT gearbox to operate so as to shift gears.
The beneficial effects of the technical scheme are as follows: when the temperature controller of the motor or the motor is higher, the gear shifting control system of the AMT gearbox controls the gear shifting of the gearbox by adopting the corrected first gear shifting curve, so that the vehicle is in a down shift or a delayed up shift in advance, the gearbox is ensured to work in a lower gear, the torque load of the motor is reduced, the temperature of the motor or the motor controller is prevented from further increasing, and the problem that the temperature of the motor or the motor controller is too high when the vehicle is in an extreme working condition of continuous ascending or continuous descending by adopting the existing gear shifting control method of the AMT gearbox is solved.
The invention provides a new energy vehicle for solving the technical problems, which comprises the AMT gearbox gear-shifting control system.
The beneficial effects of the technical scheme are as follows: when the temperature of the motor or the motor controller of the new energy vehicle is higher, the gear shifting of the gearbox is controlled by adopting the corrected first gear shifting curve, so that the vehicle is in a gear shifting down state in advance or in a gear shifting up state in a delayed manner, the gearbox is ensured to work in a lower gear, the torque load of the motor is reduced, the further temperature rise of the motor or the motor controller is avoided, and the problem that the temperature of the motor or the motor controller is too high when the vehicle is in an extreme working condition of continuous ascending or continuous descending by the existing AMT gearbox gear shifting control method is solved.
Drawings
FIG. 1 is a schematic diagram of a prior art AMT transmission base shift curve;
FIG. 2 is a schematic illustration of a first shift curve of an AMT transmission according to an embodiment of the method of the present invention;
FIG. 3 is a flow chart of a method of controlling gear shifting of an AMT gearbox according to an embodiment of the method of the present invention;
FIG. 4 is a schematic diagram of an AMT transmission control system in accordance with an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the following detailed description of the present invention will be further described with reference to the accompanying drawings.
The invention provides a gear shifting control method and system of an AMT gearbox and a new energy vehicle. The motor temperature and the motor controller temperature are combined, the existing gear shifting curve is used as a basic gear shifting curve, when the motor or the motor controller temperature is higher, the first gear shifting curve with the increased speed under the same accelerator opening degree is adopted to control the gear shifting of the gearbox, so that the vehicle is in advance in a gear or in a gear with a delay, the gearbox is ensured to work in a lower gear, the motor torque load is reduced, the motor or the motor controller temperature caused by the continuous work of the motor in a high torque is prevented from further increasing, the service life of the motor or the motor controller is prolonged, the power required by the vehicle is provided for the vehicle at a relatively higher rotating speed and a lower torque, the continuous and stable running of the vehicle is ensured, and the safety and reliability of the vehicle in running are improved.
Method embodiment
The invention provides a gear shifting control method of an AMT gearbox, which comprises the following steps:
1) Detecting the temperature of a motor and/or a motor controller, and when the temperature of the motor exceeds a first set threshold value or the temperature of the motor controller exceeds a second set threshold value, controlling gear shifting of a gearbox by adopting a first gear shifting curve, wherein the speed of the vehicle is increased under the same accelerator opening degree when the first gear shifting curve is compared with a basic gear shifting curve; the basic gear shifting curve is an existing gear shifting curve adopted when the temperature of the motor is in a normal working temperature range of the motor and the temperature of the motor controller is in a normal working temperature range of the motor controller. In this embodiment, the first set threshold is a maximum temperature threshold allowed by the motor, and the second set threshold is a maximum temperature threshold allowed by the motor controller.
2) When the temperature of the motor is higher than the normal working temperature of the motor and is lower than a first set threshold value, or the temperature of the motor controller is higher than the normal working temperature of the motor controller and is lower than a second set threshold value, a second gear shifting curve is adopted to control the gear shifting of the gearbox; and the second gear shifting curve is obtained by performing linear interpolation between the basic gear shifting curve and the first gear shifting curve according to the specific temperature.
3) When the temperature of the motor is in a normal working temperature range of the motor and the temperature of the motor controller is in a normal working temperature range of the motor controller, a basic gear shifting curve is adopted to control gear shifting of the gearbox.
In a preferred embodiment, the first shift curve is obtained by correcting the basic shift curve by shifting the basic shift curve by a set value in the direction of increasing the speed.
The basic gear shifting curve comprises a basic gear shifting curve and a basic gear shifting curve, the basic gear shifting curve is synchronously translated towards the speed increasing direction by a set value, namely, the basic gear shifting curve and the basic gear shifting curve are synchronously translated towards the speed increasing direction, the first gear shifting curve and the first gear shifting curve can be obtained, the effect of synchronously improving the gear shifting speed and the gear shifting speed is achieved, and the advanced gear shifting and the delayed gear shifting are realized. Correspondingly, the second shift profile also includes a second upshift profile and a second downshift profile. The set value is determined according to the difference between the motor rotation speed corresponding to the basic gear shifting curve and the highest motor rotation speed corresponding to the motor torque characteristic, and the set value among different gears is different because the gear speed ratios are different, and the calculation formula of the set value is as follows:
Wherein Deltaux is a set value of translation of a speed change curve of the basic gear change of the gear box x and the basic gear change of the gear x+1 in the direction of speed increase, n max is the highest rotating speed of a motor, ux is the highest vehicle speed in the speed change curve of the gear change of the gear x and the basic gear change of the gear x+1, R is the radius of a tire, i gx is the speed change of the gear box x, and i f is the main speed reduction ratio.
Taking a 4-speed gearbox as an example, as shown in fig. 2, a first shift curve of the gearbox is:
f1→2 *＝f1→2+Δu1
f1←2 *＝f1←2+△u1
f2→3 *＝f2→3+△u2
f2←3 *＝f2←3+△u2
f3→4 *＝f3→4+△u3
f3←4 *＝f3←4+△u3
Wherein, f 1→2 is a 1 st gear up 2 nd gear curve, f 1→2 * is a first 1 st gear up 2 nd gear curve, f 2→3 is a 2 nd gear up 3 rd gear curve, f 2→3 * is a first 2 nd gear up 3 rd gear curve, f 3→4 is a 3 rd gear up 4 th gear curve, f 3→4 * is a first 3 rd gear up 4 th gear curve, f 1←2 is a 2 nd gear down 1 st gear curve, f 1←2 * is a first 2 nd gear down 1 th gear curve, f 2←3 is a 3 rd gear down 2 nd gear curve, f 2←3 * is a first 3 nd gear down 2 nd gear curve, f 3←4 is a 4 th gear down 3 rd gear curve, f 3←4 * is a first 4 th gear down 3 rd gear curve, Δu1 is a gearbox Setting value of gear basic shift curve translation, and deltau 2 is/>Setting value of gear basic shift curve translation, and deltau 3 is/>The gear basic shift curve shift set value is delta u1 < delta u2 < delta u3.
To be used forFor example, the gear shift curve is modified, the maximum speed of the 2L 3 gear shift curve is u2, the gear speed ratio of the gearbox 2 is i gx, the maximum rotating speed of the motor is n max, and the ratio is/>
Further, after the corresponding gear shifting curve is selected from the basic gear shifting curve, the second gear shifting curve and the second gear shifting curve according to the temperature of the motor and/or the motor controller to control the gear shifting of the gearbox, whether the gearbox meets any gear locking strategy is further judged, and if the gear locking strategy is met, gear locking is executed.
After the vehicle starts running at the 1 st gear, after the accelerator opening and the vehicle speed reach the 1 st gear up-2 nd gear curve, executing the 1 st gear up-2 nd gear shifting action under the condition that other gear shifting conditions allow; after the throttle opening and the vehicle speed reach the 2-gear up-3-gear curve, executing the 2-gear up-3-gear shifting action under the condition that other shifting conditions allow; after the accelerator opening and the vehicle speed reach the 3-gear up-4-gear curve, the 3-gear up-4-gear shifting action is executed under the condition that other shifting conditions allow. When the vehicle runs at 4 gears, after the accelerator opening and the vehicle speed meet the 4-gear 3-gear-down curve, executing 4-gear 3-gear-down gear shifting action under the condition that other gear shifting conditions allow; after the throttle opening and the vehicle speed meet the 3-gear and 2-gear-down curve, executing the 3-gear and 2-gear-down gear shifting action under the condition that other gear shifting conditions allow; after the accelerator opening and the vehicle speed meet the 2-gear 1-gear-down curve, the 2-gear 1-gear-down gear shifting operation is executed under the condition that other gear shifting conditions allow. Other shift condition permits to mean that the vehicle does not meet a shift-up strategy, which includes:
1) And calculating the running resistance of the vehicle and the maximum driving resistance after the gear upshift when the gear upshift condition is met based on a gear upshift strategy of the dynamic gradient and the dynamic load, and executing gear upshift if the maximum driving resistance is smaller than the running resistance.
When the gearbox is controlled to shift according to a basic gear shifting curve, frequent gear shifting problems may exist in the climbing process, such as upshifting is performed after the condition of 2-gear upshift and 3-gear upshift is met in the climbing process, and after upshifting is completed, due to the reduction of the speed ratio, the torque output to the wheel end of the vehicle is reduced, the 3-gear is insufficient to drive the vehicle to continue running at the current speed, the speed is reduced again, the gear is reduced to 2-gear again, and then the gear is continuously accelerated and then is increased to 3-gear in the 2-gear running process, so that the operation is repeated. Therefore, the invention designs a gear locking strategy based on the dynamic gradient and the dynamic load, combines the dynamic gradient and the dynamic load information calculated by the vehicle, calculates the running resistance required by the vehicle to maintain the speed under the working condition in real time, and prohibits the gear-up requirement when the gear-up can not meet the running resistance provided by the vehicle, so that the vehicle maintains to run in a low gear, frequent gear shifting in the climbing process can be avoided, power interruption in the climbing process is reduced, and the driving feeling is improved.
Specifically, during the running of the vehicle, the running resistance of the vehicle is calculated in real time, when the gear shift curve indicates that the vehicle needs to perform an upshift, the real-time running resistance F x is compared with the maximum driving resistance F tx after the upshift, if F tx≥Fx + [ delta ] F, the upshift is allowed, otherwise, the current running gear is maintained unchanged. Wherein F x is running resistance, F tx is maximum total driving force of the x gear, deltaF is defined driving force gain factor, and the driving force gain factor is calibrated according to a real vehicle test, and 1000N is taken in the embodiment.
The calculation formula of F x is:
Wherein F x is running resistance, m is dynamic load of the vehicle, g is gravitational acceleration, F is rolling resistance coefficient, i is dynamic gradient value, C D is air resistance coefficient, A is windward area of the vehicle, ρ is air density, v is vehicle speed, t is time, and δ is conversion coefficient of rotational mass of the vehicle. In the embodiment, g is a constant, and 9.8m/s 2 is taken; f is a constant, and the value of f is 0.015 according to the conventional asphalt pavement; c D is a constant, 0.5 is taken; a constant, calculated according to the specific vehicle; delta is a constant, 1.1 is taken; ρ is a constant, 1.2258 N.s 2·m-4 is taken.
According to the maximum driving torque of the motor, the maximum driving resistance of the vehicle provided by different gears is calculated by combining different gear ratios of a gearbox and transmission efficiency of a power system, and the calculation formula of F tx is as follows:
wherein F tx is the maximum driving resistance of the gear x, T m is the maximum driving torque of the motor, i gx is the gear x speed ratio of the gearbox, i f is the main speed reduction ratio, R is the radius of the tire, and eta is the transmission efficiency of the power system.
2) Based on a lock-up strategy for the extreme state of the vehicle, a lock-up is performed when the vehicle anti-lock system is activated or in a slip state.
Specifically, the vehicle speed signal detected by the vehicle under the extreme working condition is unreliable, when the vehicle under the extreme working condition is detected, the vehicle is forbidden to upshift and downshift, the unexpected gear shifting probability of the vehicle under the extreme working condition is reduced, and the robustness of the vehicle gear control under the extreme working condition is improved. Extreme conditions include:
When a vehicle anti-lock braking system (ABS) is activated during wet road braking, wheels have a tendency to lock or lock, and an actual vehicle may remain at a high vehicle speed although the detected instantaneous vehicle speed signal may be low;
When a vehicle-driven anti-skid system (ASR) is activated, although the detected instantaneous vehicle speed is high, the actual vehicle speed due to the wheel slipping may be low;
the wheel is slipping but ASR is not activated, the abnormal recognition is carried out on the vehicle speed acceleration through the following formula, and if the vehicle speed acceleration exceeds a threshold value, the wheel is considered to be in a slipping state:
A is a set vehicle speed acceleration threshold value, and is set according to actual requirements; in this embodiment, a=a0+Δa, a0 is the limit acceleration that the vehicle can normally reach, Δa is the acceleration gain factor, and 1m/s2 is taken.
In addition, if the motor speed is too high and overspeed risk exists, namely the motor speed is larger than the first set speed value, an overspeed upshift protection strategy is executed, and the gearbox upshift is controlled. The first set rotation speed value can be set according to actual requirements, in this embodiment, the first set threshold value c=n max - Δn, n is the actual rotation speed of the motor, n max is the maximum allowable rotation speed of the motor given according to the motor characteristics, Δn is the overspeed protection margin, and the value range is selected according to the motor characteristics and inertia.
3) And executing gear locking when the vehicle brake feedback torque is larger than the second set value, the sliding feedback torque is larger than the third set value or the vehicle is braked and no energy feedback exists based on a gear locking strategy of braking and energy feedback.
The invention designs a gear locking strategy based on braking and energy feedback, namely, when the vehicle braking feedback torque is larger than a second set value or the sliding feedback torque is larger than a third set value in the braking and sliding processes, gear shifting is forbidden, power interruption in the energy feedback process is avoided, continuity and smoothness in the braking process are improved, driving safety is improved, and driving comfort is improved.
Specifically, after the vehicle enters a sliding mode, if the sliding feedback torque T coast is more than T0, executing a gear locking strategy, wherein T0 is a third set value, and represents a torque threshold value of sliding which does not allow gear shifting, the threshold value is calibrated by combining a speed ratio of a gearbox and a real vehicle test feeling, and the target value is that a driver cannot feel obvious braking force under the sliding feedback torque;
After the vehicle enters a braking mode, if the braking feedback torque T brake is larger than T1, executing a gear locking strategy, wherein T1 is a second set value, and represents a torque threshold of a gear shift which is not allowed by braking, the threshold is calibrated by combining a speed ratio of a gearbox and a real vehicle test feeling, and the target value is that a driver cannot feel obvious braking force under the braking feedback torque, and T1 can be the same as T0 or slightly larger than T0.
Because the multi-gear gearbox of the new energy commercial vehicle is generally not provided with a clutch and a synchronizer, under the condition of gear, a motor, the gearbox and an axle are in a rigid connection state, a gear can be returned to a gear in the gear shifting process and then a new gear is hung, a power transmission system can be disconnected firstly and then connected, the power transmission system can possibly shake, and under the condition that no energy feedback exists, but braking is stepped on, particularly under the special working condition of extreme braking, in order to ensure the smoothness of the vehicle braking process, the driving feeling in the braking process is improved, and gear shifting is still not allowed under the condition that braking is stepped on and no energy feedback exists.
Specifically, after the vehicle enters a braking mode, namely, the braking opening b is more than b0, if no energy feedback exists, executing a gear locking strategy; b is the actual brake opening, b0 is the brake opening threshold value which does not allow gear shifting, the design of the threshold value can be the same as the threshold value of the vehicle entering the brake mode, or the threshold value can be slightly larger than the opening threshold value of the vehicle entering the brake mode, and the threshold value can be set according to the actual vehicle control strategy.
Because of the difference between the motor and the engine, the engine needs to work above the lowest rotation speed and the low idle speed, the rotation speed is not allowed to be too low, and the motor does not need the motor, so that the downshift is forbidden when the downshift point is reached in the whole braking process; on the other hand, if the vehicle speed continues to rise under the condition that the braking opening degree of the downhill working condition is small, the upshift is prohibited when the upshift point is reached. After entering the gear locking strategy, if the vehicle is judged to be stopped, the gear locking is released, and a gear shifting action is executed.
As an implementation manner, in order to meet the adaptability of the vehicle to various complex working conditions and ensure the safety, reliability and comfort of vehicle driving, the invention provides a gear shift control method for cooperatively controlling multiple gear shift strategies, as shown in fig. 3.
Step 1: judging whether to correct the basic gear shifting curve according to the temperature of the motor and the motor controller, and if the temperature of the motor or the motor controller reaches the condition needing to be corrected, correcting the basic gear shifting curve, namely judging whether to calculate a first gear shifting curve and a second gear shifting curve based on the basic gear shifting curve according to the temperature of the motor and the motor controller; otherwise, directly entering the next step, and judging the lifting gear according to a basic gear shifting curve;
step 2: judging whether a gear shifting condition is met according to the basic gear shifting curve, the corrected first gear shifting curve or the corrected second gear shifting curve, and if the gear shifting condition is not met, directly maintaining the current gear; if the gear shifting condition is met, judging whether the gear shifting condition is an upshift or a downshift;
step 3: if the upshift condition is met, judging whether the upshift is required to be executed according to a upshift strategy of a dynamic gradient and a dynamic load, if the upshift is not executed, continuously judging whether the upshift is required to be executed according to a downshift strategy of an extreme state of the vehicle, if the downshift is still not executed, then judging whether the downshift is required to be executed according to a downshift strategy of braking and energy feedback, and if the downshift is still not executed, executing the upshift action; if any gear locking strategy is met, whether the gear locking is needed to be executed is judged, if the motor rotation speed has an overspeed risk, an overspeed upshift strategy is executed if the overspeed risk exists, and the current gear is maintained if the overspeed risk does not exist;
If the downshift condition is met, judging whether a gear locking is needed according to a gear locking strategy of the extreme state of the vehicle, and if the gear locking is executed, maintaining the current gear; if the gear locking is not executed, judging whether the gear locking is needed or not according to a gear locking strategy of braking and energy feedback, and if the gear locking is not needed, executing a gear-down action; if the gear locking is executed, judging whether the vehicle is parked, if the vehicle is parked, releasing the gear locking, and executing the gear down shifting; if the vehicle is not parked, the current gear is maintained.
System embodiment
The invention provides an AMT gearbox gear-shifting control system, which comprises a controller, a motor and an AMT gearbox which are in transmission connection, wherein the controller is used for executing an AMT gearbox gear-shifting control method, controlling the motor and the AMT gearbox to operate so as to shift gears, and the method is the AMT gearbox gear-shifting control method described in the embodiment of the method and is not repeated here. Preferably, the controller can be a whole vehicle controller, and as other embodiments, a separate controller can be provided to perform gear shift control of the AMT gearbox.
Taking an AMT gearbox control system of a new energy vehicle as an example, as shown in fig. 4, the system comprises a motor (Mot), a Motor Controller (MCU), a gearbox (AMT), a gearbox controller (TCU) and a whole Vehicle Controller (VCU), wherein the motor controller is connected with the motor at high voltage, the gearbox is connected with the gearbox controller at low voltage, the whole vehicle controller, the motor controller and the gearbox controller are connected through a CAN network communication, the whole vehicle controller is used for issuing instructions to the gearbox controller and the motor controller according to an AMT gearbox gear-shifting control method in the embodiment of the method, and the gearbox controller and the motor controller respectively control the AMT gearbox and the motor to operate so as to realize gear shifting.
New energy vehicle embodiment:
The new energy vehicle comprises the AMT gear shifting control system and the vehicle body, and the AMT gear shifting control method adopted by the AMT gear shifting control system is described in detail in the embodiment of the method and is not repeated here.
According to the invention, when the temperature of the motor and/or the motor controller is higher, the first gear shifting curve for improving the speed of the vehicle under the same accelerator opening degree is adopted to control gear shifting of the gearbox, and the gear shifting curve is compensated by the temperature, so that the vehicle is in a down shift or a delay up shift in advance, the gearbox is ensured to work in a lower gear, the torque load of the motor is reduced, the risk of overhigh temperature of the motor or the motor controller caused by continuous work of the motor in a high torque is avoided, the effect of the motor working in a high-speed low-torque region under the condition that the output power of the vehicle is unchanged is realized, and the safety and reliability of a vehicle power system are improved.

Claims (10)

1. The AMT gearbox gear-shifting control method is characterized by comprising the steps of detecting the temperature of a motor and/or a motor controller, and when the temperature of the motor exceeds a first set threshold value or the temperature of the motor controller exceeds a second set threshold value, controlling gear shifting of the gearbox by adopting a first gear-shifting curve, wherein the speed of the vehicle is increased under the same accelerator opening degree compared with a basic gear-shifting curve; the basic gear shifting curve is adopted when the temperature of the motor is in a normal working temperature range of the motor and the temperature of the motor controller is in a normal working temperature range of the motor controller.
2. The AMT gearbox shift control method according to claim 1, characterized in that the first shift curve is obtained by a basic shift curve translating a set value in a direction of increasing speed.
3. The AMT gearbox shift control method according to claim 2, characterized in that basic shift curves between different gears are different, setting values of translation in a direction of speed increase are also different, and a calculation formula of the setting values is:
Wherein Deltaux is a set value of translation of a speed change curve of the basic gear change of the gear box x and the basic gear change of the gear x+1 in the direction of speed increase, n max is the highest rotating speed of a motor, ux is the highest vehicle speed in the speed change curve of the gear change of the gear x and the basic gear change of the gear x+1, R is the radius of a tire, i gx is the speed change of the gear box x, and i f is the main speed reduction ratio.
4. The AMT gearbox shift control method according to claim 1, characterized in that when the motor temperature is higher than the normal operation temperature of the motor and lower than a first set threshold value, or the motor controller temperature is higher than the normal operation temperature of the motor controller and lower than a second set threshold value, the gearbox shift is controlled by using a second shift curve; the second gear shifting curve is obtained by linear interpolation between the basic gear shifting curve and the first gear shifting curve.
5. The AMT gearbox shift control method according to any one of claims 1-4, characterized in that when the gearbox is shifted by adopting the corresponding shift curve, it is further judged whether the vehicle meets any one of the gear locking strategies; the lock and gear strategy comprises the following steps:
Calculating the running resistance of the vehicle and the maximum driving resistance after upshifting when the upshifting condition is met based on a gear locking strategy of the dynamic gradient and the dynamic load, and executing gear locking if the maximum driving resistance is smaller than the running resistance;
Executing a lock-up when the vehicle anti-lock system is activated or in a slip state based on a lock-up strategy of an extreme state of the vehicle;
and executing gear locking when the vehicle brake feedback torque is larger than the second set value, the sliding feedback torque is larger than the third set value or the vehicle is braked and no energy feedback exists based on a gear locking strategy of braking and energy feedback.
6. The AMT gear shift control method of AMT gear box according to claim 5, wherein after executing the shift-up while satisfying the shift-up strategy, if it is judged that the vehicle is stopped, the shift-up is released.
7. The AMT gearbox shift control method according to claim 6, characterized in that if the motor speed is higher than a first set speed value, an overspeed upshift protection strategy is executed to control the gearbox upshift when there is an overspeed risk.
8. The AMT gearbox shift control method according to claim 5, characterized in that a calculation formula of the running resistance of the vehicle is:
Wherein F x is running resistance, m is dynamic load of the vehicle, g is gravitational acceleration, F is rolling resistance coefficient, i is dynamic gradient value, C D is air resistance coefficient, A is windward area of the vehicle, ρ is air density, v is vehicle speed, t is time, and δ is conversion coefficient of rotational mass of the vehicle.
9. An AMT gearbox shift control system comprising a controller, and a motor and an AMT gearbox in driving connection, characterized in that the controller is adapted to perform the AMT gearbox shift control method of any one of claims 1-8 to control the operation of the motor and AMT gearbox for shifting.
10. A new energy vehicle comprising the AMT gearbox shift control system of claim 9.
CN202410049616.1A 2024-01-12 2024-01-12 Gear shifting control method and system for AMT gearbox and new energy vehicle Pending CN118030826A (en)

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