离合器-离合器式自动变速器动力降档过程控制

Power-on Downshift Control for Clutch-to-clutch Automatic Transmission

动力降档是实现车辆快速提速、超车等的有效技术途径。在保证换档品质的前提下,实现动力降档,不仅需要自动变速器进行精确的离合器油压控制,而且需要发动机进行有效的转矩协调控制。针对由DEUTZ BF4M1013涡轮增压单体泵柴油机和Allison S2000离合器-离合器换档式液力自动变速器组成的动力传动系统,基于Lagrange方程建立换档过程的动力学模型,通过对降档过程各个阶段的详细分析,得到动力降档过程结合离合器和分离离合器的搭接控制时序以及控制油压的变化规律,制定基于涡轮轴转速闭环的发动机协调控制策略,在台架上进行试验验证。试验结果表明,动力降档过程的时间小于1 s,冲击度小于10 m/s3。制定的控制策略不仅实现了动力降档,而且保证了换档品质,能够进行工程实际应用。

Power-on downshift is an effective way for the vehicle to achieve rapid acceleration and overtake. To achieve smooth power-on downshift, not only the clutch hydraulic pressure should be accurately controlled, but also the engine torque should be properly controlled. Based on the DEUTZ BF4M 1013 turbo-charged electronic unit pump diesel engine and the Allison $2000 clutch-to-clutch automatic transmission, an integrated powertrain control strategy for the power-on downshift process is proposed. First of all, the dynamics model of the downshift process is derived using the Lagrange method. Then the method for controlling the oncoming clutch and the offgoing clutch is obtained, and the coordinated engine control based on the turbine speed is proposed. The experimental study is carried out on the test bench. The experimental results show that the shift time is less than 1 s, and the shift jerk of the power-on downshift process is smaller than 10m/s3. The proposed integrated powertrain control strategy for the power-on downshift process can be used for the practical engineering application.