天然气/柴油双燃料发动机油气切换过程的优化控制

为避免双燃料发动机在由纯柴油工况向双燃料工况切换过程中出现的转速大幅度波动现象,在对控制系统硬件不作较大改动的前提下,改进软件算法实现油气切换过程的平稳过渡.基于能量守恒方程,建立了油气切换过程的控制模型.在PID子模型中,采用了神经元自适应PID控制模型实现参数的在线自调整.引入了最优控制中的二次型性能指标对神经元的权值进行调整.在试验台中应用此模型对稳定转速工况下(转速为1 810 r/min,发动机有效功率为其额定功率的25%)的油气切换过程进行控制,结果显示切换过程中的转速波动率小于1.6%,实现了油气切换过程的平稳过渡,提高了整机性能.

Optimal control of oil-gas switch process of CNG/diesel dual fuel engine

In order to eliminate the speed fluctuation of the compressed natural gas(CNG)/diesel dual fuel engine in the switch process from pure oil condition to dual fuel condition, the software algorithm was improved to realize the smooth transition with little change on the control system hardware. Based on the energy conversation formula, the control model of the oil/gas switch process was built. A self-adapted PID control model based on neural cell was developed to adjust the PID parameters online, and the quadratic index of optimal control was introduced to adjust the weights of neural cell. By using the proposed model to control the oil/gas switching process under the steady condition in which the engine speed was 1 810 r/min and the engine effective power was 25% of the full load, the results showed that the maximal speed fluctuation was less than 1.6%, the smooth transition was achieved, and the engine performance was improved.