Control method and system for double-clutch two-gear speed changer

Abstract

The invention discloses a control method for a double-clutch two-gear speed changer. The control method comprises the steps that S1, the gear change is monitored; S2, when the gear is shifted up or shifted down, a first clutch is controlled to execute a separating action; S3, a torque-reduction instruction is sent to a driving motor controller; S4, whether the first clutch and a second clutch areboth in a completely separated state or not is judged; S5, if the two clutches are both completely separated, the rotating speed difference between a driving disc and a driven disc of the second clutch is obtained; and S6, the second clutch is controlled to be directly bonded according to the relation between the rotating speed difference and a preset threshold valve. The control method aims at the double-clutch two-gear speed changer, through synchronous control over a driving motor under the gear shifting working condition, the sliding friction process of the bonded clutches is reduced and even eliminated, the gear-shifting time is greatly shortened, the gear-shifting impact can be effectively reduced, the vehicle speed is more stationary at the gear shifting stage, and thus the drivingand taking experience of users can be improved.

Description

technical field [0001] The invention relates to the field of electric vehicles, in particular to a control method and system for a dual-clutch two-speed transmission. Background technique [0002] With the increasingly severe energy and environmental problems, the concept of energy conservation and environmental protection has been deeply rooted in the hearts of the people. Electric vehicles have significant advantages such as high energy efficiency and low emissions. As a "green transportation work", they have received great attention worldwide. Pure electric vehicle powertrain system matching is the primary task of pure electric vehicle development, providing input for the development of powertrain system components (drive motor, reducer, DCDC, power battery, high-voltage system). The result of powertrain system matching is directly related to whether the key objectives of the vehicle can be achieved and the cost of core components. Therefore, appropriate margin selection ...

AI Technical Summary

Problems solved by technology

Since the general pure electric vehicles adopt single-gear, there is a lack of research on DCT control for electric vehicles with dual-clutch dual-gear transmissions, and the first gear ratio in dual-gear is generally very large. When the peak speed of the motor is reduced, the speed ratio of the second gear is smaller, which leads to a larger speed ratio difference, which makes the speed difference between the two gears higher during the gear switching process; if the traditional control method is adopted, That is, the way of sliding friction first and then combining, it is very likely to cause the clutch to burn out at a high speed difference

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