Double-clutch coasting downshift control method

Abstract

The invention provides a double-clutch coasting downshift control method. The method comprises the steps that whether clutches are in an oil charging stage or not is judged in the coasting downshift process of a vehicle; if the clutches are not in the oil charging stage, whether accelerator opening degree is larger than accelerator limit value or not is detected; if the accelerator opening degreeis larger than the accelerator limit value, whether the power mode of the vehicle is in a power state or not is continuously judged; if the power mode of the vehicle is in the power state, the operation of switching coasting downshift to power downshift and simultaneously controlling rotating speed and torque is executed; and when the sliding downshift is converted into the power downshift and therotating speed and the torque are simultaneously controlled, first torque of the high-gear clutch is equal to max { first minimum torque of the high-gear clutch, first total torque of the clutch * first coefficient}, and first torque of the low-gear clutch is equal to first total torque of the clutch * (1-the first coefficient). According to the embodiment, the torque of the high-gear clutch is controlled not to be smaller than the minimum torque of the high-gear clutch in the coasting downshift stage, so that the smoothness of the vehicle in the shifting process is ensured.

Description

technical field [0001] The invention relates to the field of dual-clutch torque control, in particular to a dual-clutch sliding downshift control method. Background technique [0002] The dual-clutch automatic transmission consists of two sets of gear transmission systems, in which the odd-numbered clutches control the power transmission of odd-numbered gears, such as 1st, 3rd, 5th, and 7th gears; the even-numbered clutches control the power transmission of even-numbered gears, such as 2nd, 4th gear, 6 gear, R gear. After the control program in the transmission control unit selects the appropriate gear and completes the gear engagement, it controls the combination and separation of the odd clutch and the even clutch respectively to realize gear switching. [0003] The shift sequence of coasting downshift is clutch oil filling, torque exchange and speed adjustment. After the torque exchange stage, the working gear is switched from high gear to low gear, and the low gear clut...

AI Technical Summary

Problems solved by technology

When the torque transmitted by the low-gear clutch to the vehicle changes from braking to driving, shocks are likely to occur, affecting the driving experience

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