分速式多行星排液压混合动力系统制动能量回馈特性

城市车辆运行工况具有制动能量比例高、启停频繁的特点,非常适合应用混合动力技术,而液压混合动力相对电混合动力具有更高的功率密度,城市工况下具有更大节油潜力。为扩大调速范围,提供动力传输能力,本文提出一种双行星排混联式液压混合动力构型方案。采用机械定性分析方法研究了该系统的功率流模式,并研究了该方案不同工况下的制动能量回馈功率流和基本控制策略,分析了制动能量回收工况下液压元件的流量场特性。建立了动态系统数学模型,并基于美国测功机工况(UDDS)运行工况研究了基于基本控制策略的系统燃油经济性,系统综合节油率可达28%以上。

Braking energy recuperation characteristics of hydraulic hybrid powertrain with dual-planetary gear sets

Hydraulic hybrid powertrain has more energy saving potential than that of hybrid electric powertrain under urban driving cycle characterized as higher braking energy ratio and frequent stop-and-start operation. A new type of compound power split hybrid powertrain scheme with dual-planetary was developed in the paper. The characteristics of system power flow under braking condition were analyzed and basis control strategy was proposed. Power flow modes of hydraulic units were analyzed. The dynamic mathematic model was set up to simulate performance of the hydraulic hybrid vehicle under UDDS based on the basic control strategy. The results showed that 28% energy saving on average could be achieved.