CN115962280A - Control method and system for preventing low-rotation-speed accelerator from being stepped on to drag gear and vehicle - Google Patents
Control method and system for preventing low-rotation-speed accelerator from being stepped on to drag gear and vehicle Download PDFInfo
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- CN115962280A CN115962280A CN202310000230.7A CN202310000230A CN115962280A CN 115962280 A CN115962280 A CN 115962280A CN 202310000230 A CN202310000230 A CN 202310000230A CN 115962280 A CN115962280 A CN 115962280A
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- oil pressure
- rotating speed
- threshold value
- current gear
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Abstract
The invention discloses a control method, a system and a vehicle for preventing a low-speed accelerator from being stepped on to drag a gear, wherein the control method comprises the following steps: after an accelerator is released, if the opening of the accelerator is 0, the rotating speed of an engine is less than a first rotating speed threshold value corresponding to a current gear, the variation of the output torque of the engine in n continuous periods is less than a preset torque threshold value, and the oil temperature in a lockup clutch is greater than a preset oil temperature threshold value, controlling the actual oil pressure of the lockup clutch to be equal to an oil pressure calibration value; step two, when the accelerator is stepped on, keeping the actual oil pressure of the locking clutch unchanged until the rotating speed of the engine is greater than or equal to a second rotating speed threshold value corresponding to the current gear, and then controlling the actual oil pressure of the locking clutch to rise; and step three, when the actual oil pressure of the lockup clutch is equal to the required oil pressure of the lockup clutch, the control is quitted. The invention can realize the accurate control of the locking clutch, reduce the waste of transmission efficiency and improve the NVH performance.
Description
Technical Field
The invention belongs to the field of automobile control, and particularly relates to a control method and a control system for preventing an accelerator from being stepped on and a gear from being dragged at a low rotating speed, and a vehicle.
Background
A vehicle with an AT (automatic transmission) has the problem of dragging caused by insufficient engine torque when the vehicle is not unlocked and a small accelerator is stepped on AT a low rotating speed. The dragging gear mainly represents the vibration of the whole vehicle lasting for several seconds, and a user can sense the vibration transmitted from the positions of a steering wheel, a seat, a central control armrest box, an accelerator pedal and the like. Stepping on the accelerator to drag the gear means that the driving force of the engine is far insufficient to overcome the external resistance when the engine runs at a low rotating speed, so that the engine or a transmission system generates vibration in a short time.
In order to provide the driving force for stepping on the accelerator and ensure that the engine does not drag, an unlocking strategy (see fig. 2) is generally adopted, namely, the engine is unlocked when the accelerator is released and the rotating speed of the engine is reduced to a certain value (such as 1100 rpm), the oil pressure is discharged, a locking point is triggered when the accelerator is stepped on, and a locking command is executed after oil filling of a cylinder of the hydraulic torque converter is finished. The method has the disadvantages that the rotating speed difference between the engine and the turbine is not controlled and the locking time is long and is not controlled every time the accelerator is stepped on, so that the energy transfer efficiency is poor and the NVH performance is poor.
Disclosure of Invention
The invention aims to provide a control method and a control system for preventing an accelerator from being stepped on and a vehicle from being dragged at a low rotating speed, so that the accurate control of a locking clutch is realized, the waste of transmission efficiency is reduced, and the NVH performance is improved.
The control method for preventing the low-speed accelerator from being stepped on and the gear from being dragged comprises the following steps:
after the accelerator is released, if the opening of the accelerator is 0, the rotating speed of an engine is less than a first rotating speed threshold value corresponding to a current gear, the variation of the output torque of the engine in n continuous periods is less than a preset torque threshold value, and the oil temperature in the lockup clutch is greater than a preset oil temperature threshold value, controlling the actual oil pressure of the lockup clutch to be equal to an oil pressure calibration value, and then executing a second step; the oil pressure calibration value is obtained by inquiring a preset oil pressure calibration value table corresponding to the current gear according to the rotating speed of the engine and the output torque of the engine, and the preset oil pressure calibration value table corresponding to the current gear is a corresponding relation table of the rotating speed of the engine, the output torque of the engine and the oil pressure calibration value in the current gear. If the accelerator opening is not equal to 0, the engine still drives the automobile in the forward direction at the moment, the output torque of the engine is larger than 0, the starting rotating speed is relatively high, enough driving force is provided, and dragging does not occur. And if the rotating speed of the engine is greater than or equal to the first rotating speed threshold value corresponding to the current gear, the problem of gear dragging does not occur. The stability of the output torque of the engine is judged by utilizing the variation of the output torque of the engine in n continuous periods, which mainly prevents large oil pressure fluctuation caused by sudden load change or sudden oil cut of the engine and is not beneficial to the following control, and when the output torque of the engine is judged to be stable (namely the variation of the output torque of the engine in n continuous periods is smaller than a preset torque threshold), the oil pressure is relatively stable.
Step two, when the accelerator is stepped on, keeping the actual oil pressure of the lock-up clutch unchanged until the rotating speed of the engine is greater than or equal to a second rotating speed threshold value corresponding to the current gear, controlling the actual oil pressure of the lock-up clutch to rise, and then executing step three; and the second rotating speed threshold corresponding to the current gear is larger than the first rotating speed threshold corresponding to the current gear.
And step three, when the actual oil pressure of the lockup clutch is equal to the required oil pressure of the lockup clutch, the control is quitted.
Preferably, the slope of the rise in the actual oil pressure of the lockup clutch is: dividing the difference value of the required oil pressure of the lockup clutch and the actual oil pressure of the lockup clutch at the moment when the accelerator is stepped down by the calibration time; wherein, this calibration time obtains through keeping off the position inquiry preset calibration time table according to the current, and preset calibration time table is for keeping off the position and calibration time's corresponding relation table to it is more reasonable to make the slope that the actual oil pressure of locking clutch rises.
Preferably, in the preset oil pressure calibration value table corresponding to the current gear, the lower the engine speed is, the smaller the oil pressure calibration value is, and the minimum oil pressure calibration value is greater than or equal to the standby pressure at which the lock-up clutch is filled with oil (so that accurate and rapid execution of the lock-up command can be ensured). The lower the engine speed is, then under the condition that the engine load is not large, the oil pressure calibration value is properly reduced, so that the load which needs to be overcome by the engine after stepping on the accelerator is also as small as possible, and the engine speed can reach the second speed threshold corresponding to the current gear more easily and quickly.
Preferably, the first speed threshold corresponding to the current gear is obtained as follows: inquiring a preset first rotating speed threshold value table according to the current gear to obtain a first rotating speed threshold value corresponding to the current gear; the preset first rotating speed threshold value table is a corresponding relation table of gears and the first rotating speed threshold value.
Preferably, the second rotational speed threshold corresponding to the current gear is obtained as follows: inquiring a preset second rotating speed threshold value table according to the current gear to obtain a second rotating speed threshold value corresponding to the current gear; and the preset second rotating speed threshold value table is a corresponding relation table of gears and the second rotating speed threshold value.
Preferably, n =3.
The control system for preventing the low-speed stepping on the accelerator for dragging comprises a controller, wherein the controller is programmed to execute the control method for preventing the low-speed stepping on the accelerator for dragging.
The vehicle comprises the control system for preventing the low-speed stepping on the accelerator and the gear dragging.
According to the invention, after the accelerator is released, the actual oil pressure of the locking clutch is adjusted according to the rotating speed of the engine and the output torque of the engine, and the lower the rotating speed of the engine is, the lower the actual oil pressure of the locking clutch is; then after the rotating speed of the accelerator-stepping engine reaches a second rotating speed threshold value (namely a pressure increasing area) corresponding to the current gear, the actual oil pressure of the locking clutch rises to the required oil pressure of the locking clutch (corresponding to the output torque of the engine) within a calibration time, and the torque increasing characteristic of the hydraulic torque converter is utilized during locking, so that the driving force of stepping on the accelerator can be ensured without unlocking even if the rotating speed of the engine is low again, the accurate control of the locking clutch is realized, the execution is fast because an oil charging process is not needed, the rotating speeds of the engine and the turbine can be rapidly engaged, the waste of the transmission efficiency is reduced, the NVH performance is improved, and the problem of stepping on the accelerator and dragging the gear at the low rotating speed is reasonably solved.
Drawings
Fig. 1 is a flowchart of a control method for preventing a low-speed tip-in gear in the present embodiment.
Fig. 2 is a schematic control comparison diagram of the control method in the embodiment and the conventional control method.
Detailed Description
As shown in fig. 1 and fig. 2, the control method for preventing the low-speed tip-in of the present embodiment includes the following steps:
and S1, judging whether an accelerator released signal is received or not, if so, executing S2, and if not, ending.
And S2, judging whether the opening of the accelerator is 0, the rotating speed of the engine is smaller than a first rotating speed threshold value corresponding to the current gear, the variation of the output torque of the engine in 3 continuous cycles is smaller than a preset torque threshold value, the oil temperature in the lockup clutch is larger than a preset oil temperature threshold value, if yes, executing S3, and otherwise, returning to execute S1. And inquiring a preset first rotating speed threshold value table according to the current gear to obtain a first rotating speed threshold value corresponding to the current gear. The preset first rotating speed threshold value table is a corresponding relation table of gears and the first rotating speed threshold value and is obtained through calibration.
And S3, controlling the actual oil pressure of the lockup clutch to be equal to an oil pressure calibration value (see FIG. 2), and then executing S4. The oil pressure calibration value is obtained by inquiring a preset oil pressure calibration value table corresponding to the current gear according to the rotating speed of the engine and the output torque of the engine. The preset oil pressure calibration value table corresponding to the current gear is a corresponding relation table (obtained by calibration) of the engine rotating speed, the engine output torque and the oil pressure calibration value in the current gear, the lower the engine rotating speed in the corresponding relation table is, the smaller the oil pressure calibration value is, and the minimum oil pressure calibration value is larger than or equal to the standby pressure of the locking clutch filled with oil.
And S4, judging whether a signal that the accelerator is pressed down is received, if so, executing S5, otherwise, returning to execute S3.
S5, the lock-up clutch actual oil pressure is kept unchanged (i.e., the lock-up clutch actual oil pressure is kept unchanged at the oil pressure calibration value corresponding to the time when the accelerator is depressed), and then S6 is executed.
And S6, judging whether the engine speed is greater than or equal to a second speed threshold corresponding to the current gear, if so (namely the engine speed exceeds the speed limit and flies to a supercharging area), executing S7, and otherwise, continuing to execute S6. And inquiring a preset second rotating speed threshold value table according to the current gear to obtain a second rotating speed threshold value corresponding to the current gear. The preset second rotating speed threshold value table is a corresponding relation table of gears and the second rotating speed threshold value and is obtained through calibration. The second rotating speed threshold value corresponding to the current gear is larger than the first rotating speed threshold value corresponding to the current gear.
And S7, controlling the actual oil pressure of the lockup clutch to rise, and then executing S8. Wherein, the slope of the actual oil pressure rise of the lockup clutch is as follows: the difference between the lock-up clutch required oil pressure and the lock-up clutch actual oil pressure at the time when the accelerator is depressed (which is also the oil pressure calibration value corresponding to the time when the accelerator is depressed) is divided by the calibration time. The calibration time is obtained by inquiring a preset calibration time table according to the current gear, and the preset calibration time table is a corresponding relation table of the gears and the calibration time, so that different gears have different slopes. The oil pressure required by the lock-up clutch corresponds to the output torque of the engine, and the obtaining mode of the oil pressure corresponds to the prior art.
And S8, judging whether the actual oil pressure of the lockup clutch is equal to the required oil pressure of the lockup clutch, if so, ending (namely exiting the control), otherwise, returning to execute S7.
The embodiment also provides a control system for preventing low-speed accelerator from being stepped on for dragging, which comprises a controller, wherein the controller is programmed to execute the control method for preventing low-speed accelerator from being stepped on for dragging.
The embodiment also provides a vehicle comprising the control system for preventing the low-speed accelerator from being stepped on.
Claims (7)
1. A control method for preventing low-speed accelerator from being stepped on and a gear from being dragged is characterized by comprising the following steps of:
after the accelerator is released, if the opening of the accelerator is 0, the rotating speed of an engine is less than a first rotating speed threshold value corresponding to a current gear, the variation of the output torque of the engine in n continuous periods is less than a preset torque threshold value, and the oil temperature in the lock-up clutch is greater than a preset oil temperature threshold value, controlling the actual oil pressure of the lock-up clutch to be equal to an oil pressure calibration value, and then executing a second step; the oil pressure calibration value is obtained by inquiring a preset oil pressure calibration value table corresponding to the current gear according to the rotating speed of the engine and the output torque of the engine, and the preset oil pressure calibration value table corresponding to the current gear is a corresponding relation table of the rotating speed of the engine, the output torque of the engine and the oil pressure calibration value in the current gear;
step two, when the accelerator is stepped on, keeping the actual oil pressure of the lock-up clutch unchanged until the rotating speed of the engine is greater than or equal to a second rotating speed threshold value corresponding to the current gear, controlling the actual oil pressure of the lock-up clutch to rise, and then executing step three; the second rotating speed threshold corresponding to the current gear is larger than the first rotating speed threshold corresponding to the current gear;
and step three, when the actual oil pressure of the lockup clutch is equal to the required oil pressure of the lockup clutch, the control is quitted.
2. The control method for preventing the low-speed stepping on the accelerator for the tow-gear according to claim 1, wherein:
the slope of the actual oil pressure rise of the lockup clutch is as follows: dividing the difference value of the required oil pressure of the lockup clutch and the actual oil pressure of the lockup clutch at the moment when the accelerator is stepped on by the calibration time; the calibration time is obtained by inquiring a preset calibration time table according to the current gear, and the preset calibration time table is a corresponding relation table of the gears and the calibration time.
3. The control method for preventing a low-speed tip-in for a tow-gear according to claim 1 or 2, wherein: in the preset oil pressure calibration value table corresponding to the current gear, the lower the engine rotating speed is, the smaller the oil pressure calibration value is, and the minimum oil pressure calibration value is greater than or equal to the standby pressure of the locking clutch filled with oil.
4. The control method for preventing low-speed gas from being stepped on and the gear from being dragged according to claim 1 or 2, characterized in that:
the first speed threshold corresponding to the current gear is obtained as follows: inquiring a preset first rotating speed threshold value table according to the current gear to obtain a first rotating speed threshold value corresponding to the current gear; the preset first rotating speed threshold value table is a corresponding relation table of gears and the first rotating speed threshold value;
the second rotation speed threshold corresponding to the current gear is obtained by the following method: inquiring a preset second rotating speed threshold value table according to the current gear to obtain a second rotating speed threshold value corresponding to the current gear; and the preset second rotating speed threshold value table is a corresponding relation table of gears and the second rotating speed threshold value.
5. The control method for preventing a low-speed tip-in for a tow-gear according to claim 1 or 2, wherein: the n =3.
6. The utility model provides a prevent that low rotational speed from stepping on throttle and dragging gear's control system, includes the controller, its characterized in that: the controller is programmed to perform the control method according to any one of claims 1-5.
7. A vehicle, characterized in that: comprising a control system according to claim 6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310000230.7A CN115962280A (en) | 2023-01-02 | 2023-01-02 | Control method and system for preventing low-rotation-speed accelerator from being stepped on to drag gear and vehicle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310000230.7A CN115962280A (en) | 2023-01-02 | 2023-01-02 | Control method and system for preventing low-rotation-speed accelerator from being stepped on to drag gear and vehicle |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115962280A true CN115962280A (en) | 2023-04-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310000230.7A Pending CN115962280A (en) | 2023-01-02 | 2023-01-02 | Control method and system for preventing low-rotation-speed accelerator from being stepped on to drag gear and vehicle |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115962280A (en) |
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2023
- 2023-01-02 CN CN202310000230.7A patent/CN115962280A/en active Pending
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