无级变速汽车液力变矩器工作策略

为了提高无级变速汽车液力变矩器工作的燃料经济性,确定了液力变矩器锁止、解锁的合理条件。为了提高液力变矩器解锁时的工作效率,利用无级变速器速比调节功能,设计了PID控制器,使得发动机-液力变矩器始终工作在最佳经济区域。为了减少液力变矩器锁止时的冲击,以允许冲击度范围内滑磨功最小与发动机稳定运转2个原则,提出了锁止离合器接合的控制策略,设计了以冲击度和发动机转速差为输入量的模糊控制器。两种不同锁止情况试验结果表明:急加速(1.92 s)比缓加速(1.38 s)延长了接合时间,因此,利用控制策略能够保证锁止离合器接合平稳和发动机的稳定运转。

Work strategies of torque converter for vehicle with continuously variable transmission system

In order to improve the operating fuel economy of torque converter for vehicle with continuously variable transmission(CVT) system,the optimal lock-up and unlocking conditions were confirmed.To furtherly improve the work efficiency of torque converter in unlocking stage,PID controller was designed,so that engine and torque converter worked in optimal economy region by adjusting the speed ratio of CVT.To decrease the impact during the lock-up process of torque converter,the control strategies of lock-up clutch engagement were put forward according to the principles of stabilizing engine rotation and optimizing the performance of impact and sliding friction work,and the fuzzy controller with two inputs of impact degree and rotate speed difference was designed.The experimental result under two kinds of different lock-up states shows that the 1.92 s in quick acceleration is bigger than the 1.38 s in slow acceleration,the engagement time is prolonged,so the control measures can ensure the engaging smoothness of torque converter and stabilize engine rotate speed.6 figs,11 refs.