线性机电混合动力系统换气多场耦合动力学机理与失稳调控

The operation of the linear free-piston electro-mechanical hybrid generator (LEHG) is the coupling result of combustion drive, power transmission, magnetoelectro induction, gas exchange and other processes, and the gas exchange of the LEHG easily leads to in-cylinder fresh charge variation due to the effect of combustion cycle variation, intensifying operation instability in subsequent cycle. The project focuses on two fundamental scientific issues of LEHG gas exchange, which are the "multi-field coupling dynamics mechanism" and "instability regulation mechanism". Based on the analysis of the multi-parameter coupling relationship in the LEHG power transmission process, a gas exchange model which couples with the combustion, thermodynamic conversion, transmission, power generation and system dynamics is developed to explore the influence mechanism of the machine-electrical-fluid-thermal coupling parameters on the LEHG gas exchange; By investigating the relationship among the combustion drive, the dynamic coupling mechanism of transmission components and the scavenging boundary, the formation mechanism and change law of converting the combustion variation into the scavenging instability is explored through machine-electric-fluid-thermal coupling mechanism. In terms of improving the gas exchange stability, this project presents a control concept that regulates the flow area of the scavenging port to achieve stable scavenging charge, and the synergistic mechanism between the induced factors and regulatory factors of scavenging instability is studied. Besides, the required conditions of port flow area that can maintain stable scavenging charge under the combustion variation are explored, and the control method of gas exchange that can satisfy the stable margin of the charge and the requirement of the combustion variation-resistant is obtained.

线性自由活塞机电混合动力系统（LEHG）的运行是燃烧驱动、动力传递、磁电感应、气体交换等过程相互耦合的结果，其换气受到燃烧循环变动的作用容易导致缸内新鲜充量波动，加剧后续循环运行失稳。本项目围绕LEHG换气“多场耦合动力学机理”与“失稳调控机理”2个基础科学问题展开。在分析LEHG动力传递过程多场参数耦合关系的基础上，构建燃烧、热力转换、传动、发电及系统动力学复杂耦合的LEHG换气分析模型，探寻机-电-流-热耦合参数对LEHG换气的作用机理。通过研究燃烧驱动、传动组件动力学耦合机制与换气边界的关系，探寻燃烧变动通过机-电-流-热耦合机制转换成换气失稳的形成机理与变化规律。在提高换气稳定能力的途径方面，项目引入一种调控扫气口流通面积实现换气充量稳定的控制思想，研究换气失稳的诱发因子与调控因子之间的协同机理，探究燃烧变动下维持换气充量稳定的气口流通面积条件，获得满足充量稳定裕度的换气控制方法。

线性自由活塞机电混合动力系统（LEHG）是一种采取直线驱动-传动-换能的新型混合动力。然而，多场耦合下的换气失稳成为制约其工程化、商品化发展的关键挑战之一。本项目通过分析LEHG换气过程的机-电-流-热多场参数耦合关系，构建了耦合动力学、热力学和磁电学的系统换气流通模型，数值研究了多场复杂耦合下LEHG换气废气清扫和新鲜充量捕获的演变特征。同时，探究了LEHG换气流通性能随燃烧变动的失稳规律，并利用机-电-流-热多场耦合机理将燃烧变动转换成换气流通边界的变化，分析了燃烧循环变动通过机-电-流-热多场耦合动力学行为转换成换气失稳的形成机制，揭示了燃烧性能波动时LEHG换气充量失稳的发生条件。项目还提出了调控换气流通面积的控制思路，分析了调控气口流通面积与失稳诱发因子的相互作用关系和协同原理，并基于机-电-流-热多场耦合机制、换气失稳机理及协同控制关系建立了自抗扰换气控制模型，研究获得了一种满足缸内新鲜充量稳定裕度和抗燃烧扰动要求的换气控制方法。

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