阅读说明：本技术 混合动力越野车重型减速箱自动换挡控制方法 (Automatic gear shifting control method for heavy reduction gearbox of hybrid off-road vehicle ) 是由 谢锡春 李进伟 余翔宇 付畅 汪振晓 于 2020-05-01 设计创作，主要内容包括：本发明公开了一种混合动力越野车重型减速箱自动换挡控制方法,其特征在于,包括步骤1)获取参数判断是否进入电机前驱模式；2)判断是否进入动态自动换挡模式；3)根据SOC和实际加速度优先控制档位；4)摘挡过程中同步调节电机转速与转矩；5)挂挡过程中执行油门恢复。本发明电机转速调节与减速箱摘挡过程同步进行,电机转矩调节与减速箱挂挡过程同步进行,保证了电机转速和转矩调节与减速箱换挡的同步性,缩短了换挡时间。且车速信息更加准确,并保持了路况加速度在换挡前后的一致性。保证了电机转速与转矩的匹配度,提高了换挡的平顺性。(The invention discloses an automatic gear shifting control method for a heavy reduction gearbox of a hybrid off-road vehicle, which is characterized by comprising the following steps of 1) obtaining parameters and judging whether to enter a motor forerunner mode; 2) judging whether to enter a dynamic automatic gear shifting mode; 3) preferentially controlling gears according to the SOC and the actual acceleration; 4) synchronously adjusting the rotating speed and the torque of the motor in the gear-off process; 5) and executing throttle recovery in the gear engaging process. According to the invention, the motor rotating speed adjustment and the reduction gearbox gear-off process are carried out synchronously, the motor torque adjustment and the reduction gearbox gear-on process are carried out synchronously, the synchronism of the motor rotating speed and torque adjustment and the reduction gearbox gear-shifting is ensured, and the gear-shifting time is shortened. The speed information is more accurate, and the consistency of the road condition acceleration before and after gear shifting is kept. The matching degree of the rotating speed and the torque of the motor is ensured, and the gear shifting smoothness is improved.)

1. An automatic gear shifting control method for a heavy reduction gearbox of a hybrid off-road vehicle is characterized by comprising the following steps:

1) after the automobile is powered on, acquiring a driving mode signal and a speed;

2) when the driving mode is an engine rear-drive mode, the reduction gearbox executes forced neutral gear; when the driving mode is a motor-engine dual-driving mode, the gear of the reduction gearbox is consistent with the gear of the transfer case; when the driving mode is a motor forerunner mode, judging whether to enter a dynamic automatic gear shifting mode according to the speed of the vehicle;

3) when the dynamic automatic gear shifting mode is not entered, the steps 1) to 2) are circulated; when entering a dynamic automatic gear shifting mode, acquiring a current gear, a motor rotating speed, a motor torque, a battery charge state SOC, an accelerator size and a brake signal;

4) if the SOC of the battery is smaller than the critical value, switching to a low gear and keeping the SOC unchanged; otherwise, calculating the actual acceleration;

5) when the actual acceleration is larger than or equal to the acceleration critical value, keeping the current gear unchanged; otherwise, determining the gear shifting time according to the motor rotating speed-vehicle speed-accelerator gear shifting Map;

6) the reduction gearbox executes gear picking, controls the torque of the motor to be 0 at the same time, and calculates the target rotating speed of the motor according to the vehicle speed;

7) and when the rotating speed of the motor reaches the target rotating speed, the reduction gearbox executes gear engagement, controls the torque of the motor to enable the road condition acceleration to be consistent with the current road condition acceleration, finishes gear shifting, and circulates the steps 3) -7).

2. The automatic gear shifting control method for the heavy gearbox of the hybrid off-road vehicle according to claim 1, characterized in that: in the step 2), a driving mode signal is determined through a high-low gear change-over switch, a reduction gearbox forced neutral switch and a transfer case forced neutral switch, when the reduction gearbox forced neutral switch and the transfer case forced neutral switch are both closed, the driving mode is a motor-engine dual-driving mode, and gear shifting is carried out through the high-low gear change-over switch; when the positive neutral switch of the reduction gearbox is turned on and the positive neutral switch of the transfer case is turned off, the driving mode is an engine rear-driving mode; when the positive neutral switch of the reduction gearbox is closed and the positive neutral switch of the transfer case is opened, the driving mode is a motor forerunner mode.

3. The automatic gear shifting control method for the heavy gearbox of the hybrid off-road vehicle as claimed in claim 2, characterized in that: and step 2), in the motor forerunner mode, when the vehicle speed is greater than or equal to the vehicle speed critical value, entering a dynamic automatic gear shifting mode.

4. The automatic gear shifting control method for the heavy gearbox of the hybrid off-road vehicle as claimed in claim 3, wherein: in step 4), the calculation formula of the actual acceleration is

Wherein u is the vehicle speed, t is the time, m is the vehicle mass and is the rotating mass conversion coefficient, and A, B, C, D are all fitting coefficients.

5. The automatic gear shifting control method for the heavy gearbox of the hybrid off-road vehicle as claimed in claim 4, wherein the method comprises the following steps: and 6), adjusting the working frequency and the working current of the motor to realize the rotation speed of the motor.

6. The automatic gear shifting control method for the heavy gearbox of the hybrid off-road vehicle as claimed in claim 5, wherein the method comprises the following steps: and 7), the road condition acceleration is equal to the actual acceleration multiplied by the peak torque/the transient torque, wherein the peak torque is a fixed value of the motor, and the transient torque is an adjustable change value.

7. The automatic gear shifting control method for the heavy gearbox of the hybrid off-road vehicle according to claim 1, characterized in that: and 4) in the steps 4) to 7), if the braking signal indicates that the automobile is braking, the reduction gearbox returns to the neutral gear.

Technical Field

The invention relates to the technical field of automobile gearbox control, in particular to an automatic gear shifting control method for a heavy reduction gearbox of a hybrid off-road vehicle.

Background

With the development of hybrid off-road vehicles, a transmission device and a driving motor are indispensable key assemblies, and the coordinated control technology of the transmission device and the driving motor is the key for the development of the whole electric driving assembly. Because the rotating speed-torque characteristic of the motor is close to the ideal vehicle running characteristic, a motor direct-drive scheme is mostly adopted during pure electric driving. However, the vehicle adopting the transmission scheme cannot ensure that the motor works in a high-efficiency region in the whole running process, the energy-saving effect is influenced to a certain extent, meanwhile, the transmission mode has higher requirements on the performance of the motor and the battery, the rotating speed needs to reach more than 10000r/min to meet the running requirements of the vehicle, otherwise, the dynamic property of the vehicle is limited, and therefore the motor direct-drive scheme limits effective improvement of the performance of the pure electric vehicle. The pure electric vehicle adopting the direct-drive mode has the advantages that although the efficiency of the high-efficiency area of the motor can reach more than 95%, the efficiency of the low-efficiency area of the motor is only about 70%, and therefore the motor efficiency is very low under most running conditions. In order to improve the dynamic property and the economical efficiency of the vehicle and simultaneously reduce the requirements on a traction motor and a battery, the multi-gear is a development trend of a transmission system of an electric vehicle.

At present, the common two-gear reduction box transmission scheme utilizes the switching of the speed ratio of the speed reducer, can greatly reduce the highest running rotating speed of a motor, improve the running environment of the motor, simultaneously reduce the performance requirement of a vehicle on a battery, and improve the low-speed climbing capacity and the highest running speed of the vehicle through the speed ratio for the performance of the whole vehicle. The two-gear reduction box can reduce energy consumption and the size and weight of the whole driving chain.

The hybrid power heavy off-road vehicle has complex running condition and large dead weight, needs large motor traction force when starting and accelerating climbing, has high requirement on the torque range of a driving motor, and also needs to meet the requirement of the highest vehicle speed, so that the speed ratio difference of a two-gear reduction box is inevitably large, the prior art controls the reduction box with large speed ratio difference, and the requirements on gear shifting time and gear shifting smoothness are hardly considered.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide the automatic gear shifting control method for the heavy reduction gearbox of the hybrid off-road vehicle, which has the advantages of short gear shifting time and higher gear shifting smoothness.

In order to achieve the aim, the invention provides an automatic gear shifting control method for a heavy reduction gearbox of a hybrid off-road vehicle, which is characterized by comprising the following steps of:

1) and after the automobile is powered on, acquiring a driving mode signal and the speed.

2) When the driving mode is an engine rear-drive mode, the reduction gearbox executes forced neutral gear; when the driving mode is a motor-engine dual-driving mode, the gear of the reduction gearbox is consistent with the gear of the transfer case; and when the driving mode is the motor forward driving mode, judging whether to enter a dynamic automatic gear shifting mode according to the vehicle speed.

3) When the dynamic automatic gear shifting mode is not entered, the steps 1) to 2) are circulated; when entering a dynamic automatic gear shifting mode, the current gear, the motor rotating speed, the motor torque, the battery charge state SOC, the accelerator size and a brake signal are obtained.

4) If the SOC of the battery is smaller than the critical value, switching to a low gear and keeping the SOC unchanged; otherwise, the actual acceleration is calculated.

5) When the actual acceleration is larger than or equal to the acceleration critical value, keeping the current gear unchanged; otherwise, determining the gear shifting time according to the motor rotating speed-vehicle speed-accelerator gear shifting Map.

6) The reduction gearbox executes gear-off, simultaneously controls the torque of the motor to be 0, and calculates the target rotating speed of the motor according to the vehicle speed.

7) And when the rotating speed of the motor reaches the target rotating speed, the reduction gearbox executes gear engagement, controls the torque of the motor to enable the road condition acceleration to be consistent with the current road condition acceleration, finishes gear shifting, and circulates the steps 3) -7).

Further, in the step 2), a driving mode signal is determined through a high-low gear change-over switch, a reduction gearbox forced neutral switch and a transfer case forced neutral switch, when the reduction gearbox forced neutral switch and the transfer case forced neutral switch are both closed, the driving mode is a motor-engine dual-driving mode, and gear shifting is carried out through the high-low gear change-over switch; when the positive neutral switch of the reduction gearbox is turned on and the positive neutral switch of the transfer case is turned off, the driving mode is an engine rear-driving mode; when the positive neutral switch of the reduction gearbox is closed and the positive neutral switch of the transfer case is opened, the driving mode is a motor forerunner mode.

Further, in the step 2), in the motor forward driving mode, when the vehicle speed is greater than or equal to the vehicle speed critical value, the dynamic automatic gear shifting mode is entered.

Further, in step 4), the calculation formula of the actual acceleration is

Wherein u is the vehicle speed, t is the time, m is the vehicle mass and is the rotating mass conversion coefficient, and A, B, C, D are all fitting coefficients.

Further, in step 6), the rotation speed of the motor is realized by adjusting the working frequency and the working current of the motor.

Further, in step 7), the road condition acceleration is equal to the actual acceleration × the peak torque/the transient torque, where the peak torque is a fixed value of the electric machine, and the transient torque is an adjustable variable value.

Further, in the steps 4) to 7), if the braking signal indicates that the automobile is braking, the reduction gearbox returns to the neutral gear.

The invention has the beneficial effects that: the gear shifting time is short, and the gear shifting smoothness is higher. The motor speed regulation and the reduction gearbox gear-off process are carried out synchronously, the motor torque regulation and the reduction gearbox gear-on process are carried out synchronously, the synchronism of the motor speed and torque regulation and the reduction gearbox gear shifting is ensured, and the gear shifting time is shortened. And the speed information is calculated by acquiring the pulse distance of the wheel through a motor speed sensor, and the consistency of the road condition acceleration before and after gear shifting is kept. The matching degree of the rotating speed and the torque of the motor is ensured, and the gear shifting smoothness is improved.

Detailed Description

The invention will be described in further detail below to facilitate a clearer understanding of the invention, but they are not intended to limit the invention.

An automatic gear shifting control method for a heavy reduction gearbox of a hybrid off-road vehicle is characterized by comprising the following steps:

1. and after the automobile is powered on, acquiring a driving mode signal and the speed.

2. When the forced neutral switch of the reduction gearbox and the forced neutral switch of the transfer case are both closed, the driving mode is a motor engine dual-driving mode, the gears are shifted through the high-low gear change-over switch, and the gears of the reduction gearbox and the gears of the transfer case are kept consistent; when the forced neutral switch of the reduction gearbox is turned on and the forced neutral switch of the transfer case is turned off, the driving mode is an engine rear-driving mode, and the reduction gearbox executes forced neutral; when the reduction gearbox forced neutral switch is turned off and the transfer case forced neutral switch is turned on, the driving mode is a motor forward driving mode, and whether the dynamic automatic gear shifting mode is entered or not is judged according to the vehicle speed.

3. When the vehicle speed is smaller than the vehicle speed critical value and the dynamic automatic gear shifting mode is not entered, the steps 1) to 2) are circulated; when the vehicle speed is greater than or equal to the vehicle speed critical value, entering a dynamic automatic gear shifting mode, and acquiring a current gear, the motor rotating speed, the motor torque, the battery charge state SOC, the accelerator size and a braking signal.

4. At any time of the dynamic automatic gear shifting mode, if the braking signal shows braking, the reduction gearbox returns to the neutral gear, and the safety of the reduction gearbox is ensured.

5. If the SOC of the battery is smaller than the critical value, the battery is switched to a low gear and is kept unchanged, so that high-grade high-speed driving is avoided when the remaining battery is small, and the endurance mileage is prolonged; otherwise, the actual acceleration is calculated. The actual acceleration is calculated by the formula

Wherein u is the vehicle speed, t is the time, m is the vehicle mass and is the rotating mass conversion coefficient, and A, B, C, D are all fitting coefficients.

6. When the actual acceleration is larger than or equal to the acceleration critical value, the automobile is considered to be going uphill, the current gear is kept unchanged in the uphill process, the driving stability of the automobile is facilitated, the automobile speed is gradually reduced, and the low gear is kept unchanged after the gear is changed from the high gear to the low gear; otherwise, determining the gear shifting time according to the motor rotating speed-vehicle speed-accelerator gear shifting Map.

7. The reduction gearbox executes gear-off, simultaneously controls the torque of the motor to be 0, and calculates the target rotating speed of the motor according to the vehicle speed. The motor torque is adjusted to be 0 so as to avoid additional torque existing when the driving gear is meshed with the meshing gear in the gear shifting process and avoid gear shifting difficulty. The vehicle speed is obtained by the pulse distance at the wheel acquired by the rotating speed sensor of the motor through sending a pulse signal; the rotating speed of the motor is realized by adjusting the working frequency and the working current of the motor. Therefore, the information of the vehicle speed is more accurate, and the adjustment of the rotating speed of the motor is more accurate. The rotation speed of the motor is adjusted synchronously with gear shifting, so that the gear shifting synchronism is utilized, and the gear shifting time is shortened.

8. When the rotating speed of the motor reaches the target rotating speed, the reduction gearbox executes gear engagement, and meanwhile, the torque of the motor is controlled to enable the road condition acceleration to be consistent with the current road condition acceleration, wherein the road condition acceleration is the actual acceleration multiplied by the peak torque/the transient torque, the peak torque is a fixed value of the motor, and the transient torque is an adjustable change value. Completing the gear shifting and circulating the steps 3) to 7).

The motor rotating speed regulation and the reduction gearbox gear-off process are synchronously carried out, the motor torque regulation and the reduction gearbox gear-on process are synchronously carried out, the synchronism of the motor rotating speed and torque regulation and the reduction gearbox gear-shifting is ensured, and the gear-shifting time is shortened. And the speed information is calculated by acquiring the pulse distance of the wheel through a motor speed sensor, and the consistency of the road condition acceleration before and after gear shifting is kept. The matching degree of the rotating speed and the torque of the motor is ensured, and the gear shifting smoothness is improved.