Optimized control of engine start assisted by the disconnect clutch in a P2 hybrid automatic transmission
Optimized control of engine start assisted by the disconnect clutch in a P2 hybrid automatic transmission
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DOI：
10.1016/j.ymssp.2019.01.052
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发表时间：
2019-06
影响因子：
8.4
通讯作者：
X. Xu;Yi-Hao Liang;M. Jordan;P. Tenberge;P. Dong
中科院分区：
文献类型：
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作者：
X. Xu;Yi-Hao Liang;M. Jordan;P. Tenberge;P. Dong
在P2混合动力自动变速器中，发动机可以通过分离离合器打滑来启动，而不是使用传统的起动器。然而，乘坐舒适性和发动机启动时间都是启动过程控制的挑战。为了实现发动机平稳快速的启动，针对不同的发动机启动情况，提出了一种优化控制策略。首先，建立了P2混合动力总成模型，用于描述发动机启动过程中的暂态行为，为控制策略的制定提供支持。在此基础上，提出了一种多阶段控制策略，根据不同的驾驶情况，实现了平顺性好或启动时间短的控制目标。设计了一种基于微分平坦度和比例积分导数(PID)算法的非线性前馈控制器，用于直接操作电磁阀的电流调节。从而可以微调分离离合器的压力，实现对发动机转速参考轨迹的良好跟踪能力。仿真和试验结果表明，所提出的控制策略和控制器能够满足发动机不同的启动要求。P2混合动力汽车在发动机启动过程中，可以有效地提高乘坐舒适性和发动机启动时间。
Instead of using conventional starter, engine can be started through slipping of the disconnect clutch in P2 hybrid automatic transmission. However, both riding comfort and engine-start time are challenges for control of the starting process. In order to achieve smooth and quick engine start, this paper proposed an optimized control strategy with respect to different engine-start situations. Firstly, a model of P2 hybrid powertrain is developed to characterize the transient behavior during engine start and provide support for developing control strategies. A multiphase control strategy is then proposed to cope with the control objective of either good riding comfort or short starting time depending on different driving situations. A nonlinear feedforward-feedback controller based on differential flatness and proportional-integral-derivative (PID) algorithm is developed to regulate the current of direct operating solenoid valve. Thus the pressure of the disconnect clutch can be fine-tuned and good tracking capability for the reference trajectory of engine speed can be realized. Finally, simulation and test results demonstrate that the proposed control strategy and controller can satisfy different requirements for engine start. Both riding comfort and engine-start time of a P2 hybrid vehicle can be effectively improved in the engine starting process.