漏电流式颗粒物传感器电荷传输与PM浓度间瞬态响应特性的研究

Around the key issues about the construction of the prototype mechanism in new sensor which can measure low particle concentration in real time，the combination method of theoretical analysis and experimental verification are adopted in this project, and the transient response characteristics between charge transport and particle concentration in the leakage current PM sensor are studied, then physical model of particulate matter sensor in two modes of natural charge and uncharged particulate matter is established and the action mechanism of the sensor characteristics related to the charge transfer between the electrodes of the sensor is revealed. The correlation function between the sensor output signal and the electrode spacing, the electrode length, the high electrode voltage, the particle concentration is also constructed. Moreover, the flow pattern and variation inside the sensor and the evolution mechanism of the flow field and the electric field are studied according to the construction of finite-element multi-physics model and CFD calculation method. At the same time, the change regulation of factors such as installation location, structural parameters of the sensor, exhaust gas temperature, velocity of flow, particle size distribution and morphology, which affect sensor sensitivity are revealed and the method for improving the sensitivity of the sensor is analyzed.Additionally, mechanism of DPF failture diagnosis based on instantaneous measuring principle of PM sensor is also studied. Regarding promotion PM sensor in the application of domain in OBD of diesel engine and the formation of proprietary intellectual property rights, the vital significance can be found based on this project research.

围绕能实时测量颗粒物浓度的新型传感器原型机理构建的关键问题，本项目采用理论分析和试验验证相结合的方法，研究漏电流式颗粒物传感器电荷传输与颗粒物浓度间的瞬态响应特性，建立自然电荷和不带电颗粒两种模式下的传感器物理模型，揭示控制与传感器电极间电荷传输相关的传感器瞬态特性的作用机制，建立传感器输出信号和电极间距、电极长度、电极电压、排气流速、颗粒物浓度之间的关联函数，通过有限元多物理模型和CFD计算方法的构建研究传感器内的流动形式及变化规律，探究流场和电场耦合的演化机理，研究传感器安装位置、传感器结构参数、废气温度、流速、颗粒尺寸分布和形态等因素影响传感器灵敏度的变化规律，分析提高传感器灵敏度的方法，研究基于颗粒物传感器瞬时测量原理的DPF失效诊断机理。本项目研究对于促进颗粒物传感器在柴油机OBD领域应用与技术提升，形成自主知识产权有重要的意义。

为满足日益严格的OBD排放法规要求，有效监测DPF系统的工作状态并保证后处理系统能够稳定、连续运行，因此迫切需要研究能实时测量低浓度颗粒物的新型传感器。本课题采用理论分析和试验验证相结合的方法探究漏电流式颗粒物传感器不同带电模式下的工作机理，研究漏电流式颗粒物传感器电荷传输与PM浓度间瞬态响应特性和作用机制，分析影响传感器灵敏度的重要因素和耦合关联机理，获得影响颗粒物传感器瞬态信号输出的关键因素及变化规律，建立传感器输出的瞬态电压信号与颗粒物浓度的关联函数，实现基于颗粒物传感器瞬时测量原理的DPF失效诊断的研究目标。. 本课题通过构建柴油机DPF后处理试验系统，分别进行了漏电流式颗粒物传感器瞬态响应特性研究；漏电流式颗粒物传感器多场作用研究；对漏电流式颗粒物传感器电极参数影响机理进行研究，得出传感器电极间距、电极长度、电极电压和废气速度等对传感器输出信号变化规律的关系；分析基于DPF后端安装的颗粒物传感器输出信后限值的DPF失效模式与发动机运行工况的关联性。研究结果对于促进颗粒物传感器在柴油机OBD领域应用与技术提升，形成自主知识产权有重要意义。. 在本项研究过程中，按照预定试验方案认真分析并解决了研究过程中的各项科学问题及关键技术，圆满完成了本项目的所有研究工作。对各阶段研究工作进行了及时总结，依托本项目资助，目前已发表学术论文14篇（其中，SCI收录5篇、EI收录6篇），参加各类重要学术会议7次，申请PCT专利2件，授权发明专利6件，培养硕士研究生6名，鼓励并支持研究生参加了多项科研赛事，并取得了良好成绩。