基于参数协同关联的汽油机性能控制方程的构建与类似性准则研究

With new technologies constantly adapted in modern gasoline engines, the dimensions and breadths of design parameters and control variables are increasing. The traditional approach of sequential scanning based engine performance simulations or bench tests encountered a number of bottlenecks, not only the huge numbers of optimization runs to be performed would cause fast increase in the development time duration and costs, but also it is easy to loss the direction of optimization, due to the fast increasing in the dimensions and scales of the variables. This study will try to establish the inner relationship among the engine performances with all the major influencing parameters, in the format of controlling equation groups, based on a comprehensive analysis to the data acquired from performance benchmarking tests and structural analysis of multiple advanced gasoline engines. The research approach includes application of conservation laws in the mass, energy and dynamics, as well as dimensional analysis methods, on to the processes of mass and heat transfer, combustion and thermal to mechanical energy conversion in gasoline engines. In the end to establish the quantitive relationship between the engine performances with design, control, as well as operational parameters, in the format of controlling equations groups; The equations such established are then applied on to different gasoline engines of the same type and the robustness of those equations will be verified and corrected; Finally, the similarity criteria and the cross-transplant theory will be examined and developed for engine design, controlling, and operational parameters. The results of this project will provide theoretic basis as well as a method to greatly reduce the number of simulations runs and tests, to greatly shorten the development time and costs of a new engine, and to acquire a piece of core design technology with independent intellectual property rights.

由于新技术的不断引进，现代汽油机的设计参数以及控制变量的维度与广度在日益增加。传统的、基于顺序扫描的参数优化方法，面临着样本量呈几何级数增加而导致的工作量巨大、易于迷失优化方向等瓶颈问题。本项目首先拟对前期获得的多台先进汽油机的性能对标试验与结构解析数据进行二次开发，力图在性能与结构以及控制、运行参数之间进行关联，提炼关键参数；基于机理推导以及无因次分析方法对现代汽油机中的传热传质、燃烧以及热功转换过程开展深度解析，导出包含主要设计、控制以及运行参数在内的动力性、经济性能控制方程组；然后在不同的发动机之间进行交叉验证，总结共性规律。本项目拟研究包含主要设计、控制、运行参数的汽油机性能控制方程组的构建方法、和基于类似性准则的参数交叉移植理论这两个关键科学问题。本项目的成果将为减少汽油机开发过程中的参数扫描次数与开发费用，形成具有自主知识产权的核心设计技术，提供理论依据及应用方法。

由于新技术的不断引进，现代汽油机的设计参数以及控制变量的维度与广度在日益增加。传统的、基于顺序扫描的参数优化方法，面临着样本量呈几何级数增加而导致的工作量巨大、易于迷失优化方向、开发周期长等瓶颈问题。为了简化发动机正向开发工作过程、提高产品开发效率，本项目基于参数协同关联的方法开展汽油机性能控制方程构建与类似性准则的研究，并取得了多项有实用意义的成果。首先通过对多台先进汽油机的性能对标试验与结构解析数据进行二次开发，提出了一种发动机控制参数和缸内状态参数检测方法。通过信号实测与数模仿真动态耦合求解，开发了一种发动机多控制参数同步在线采集的通用方法，可适用于整车台架稳态以及路试瞬态工况下发动机参数在线同步采集。其次，对影响发动机性能的主次要参数进行甄别，利用量化分析的研究方法并结合气体动力学和热力学原理，建立了发动机主要性能参数的梯级分解理论。通过机理推导与参数关联性研究将性能参数分解成设计、控制和运行参数的函数，提出了包含现代汽油机中各主要影响参数的动力性能控制方程组并基于发动机稳态实验数据进行了验证。最后，基于台架试验数据及整车试验数据搭建了汽油车详细机理数值仿真模型，破解了瞬态工况发动机关键性能、燃烧参数及能量特性的影响机制。通过建立基准数模与预测模型，开发了发动机油耗和扭矩在线检测模型并进行验证。本项目采用类似性准则移植得到绝大部分对发动机性能有重要影响的设计与运行参数，可以有效减少新品发动机待选择、待优化参数的个数和变化范围，呈几何级数地减少开发过程中仿真扫描或台架标定的样本数与工作量，指引发动机性能目标的实现，大大提高开发工作的效率，项目研究结果具有重大的工程应用潜力。