Research On Virtual-Prototype-Based Design Method Of Internal Combustion Engine Subsystems

Taking the design methods of the internal combustion engine (I.C.E.) sub-systems and their parts as the research objects, this dissertation mainly discusses what role the Virtual Prototype (VP) technique can play in the process of designing those objects above.This dissertation conducts detailed research on the functions of VP. Moreover, in connection with projects and by defining design procedures, this dissertation applies the connotation of VP into the engineering issues. Practically, the feasibility and dependability of these design modes, have been proved.It can be concluded that the main functions of VP contains: Implement of performance prediction, Foundation of dynamic optimization, providing assistance to other analysis implements. Based on these functions, a series of design methods has been developed, including Dynamic optimization, Dynamic topology optimization, Dynamic lightening method and Dynamic balancing method. Subsequently, this dissertation applies these methods above into such aspects as, Dynamic performance analysis, Performance optimization, Dynamic lightening design, Dynamic balance optimization, and so on.Mainly aiming at two subsystems of I.C.E., crank-train and valve-train, these methods mentioned above have been applied into such objects as, CAM profile, rocker arm frame, engine block, crankshaft counterweights, and so on.The research of this dissertation includes following initiative works:1. Aiming at the dynamic parameters of valve spring, a detailed research on the parameterization of valve spring has been conducted. By utilizing nonlinear FEM, the stiffness characteristic simulation of valve spring can be obtained.2. Mainly based on the parameterization modeling technique, the different steps in traditional cam profile design mode have been reorganized into an upgraded mode named "Parameterized-prototype-based Cam Profile Dynamic Optimization Mode".3. Aiming at the problems in Topology Optimization of the parts in operating mechanism, an effective solution, which integrated VP and Topology Optimization, has been puts forward. The risk of the single-operating-moment-oriented Topology Optimization can be avoided.4. Aiming at the current problems in the strength calculating of lightening design process, such as, static loads and boundary conditions, a dynamic lightening method, based on VP, was proposed as a solution.5. During the above-mentioned course of engine block lightening design, a new-proposed concept of Composite MPCs has been introduced into the pre-processing of FEM modeling, by which the relation between VP and FE model can be constructed.6. Aimming at such problems as extracting the load-time-history, an effective solution, named VP-based multiaxial fatigue life prediction, has been proposed, which integrates FEM, dynamics simulation and fatigue calculation.7. Aiming at the deficiencies in crankshaft counterweights design, a VP-based dynamic optimization of crankshaft counterweights was executed. Calculation results indicate that the success of optimal course depends on appropriate choice on optimal objective.