关键词：汽车；定性和定量建模；扩展变换方法；装配
摘 要：This paper presents an Extension theory-based approach to product design,the basic idea is to use combined qualitative and quantitative modeling in Extenics to describe the user's possible product using process as well as the corresponding internal structural,assembly and motion relationships of product, then mark the contradictory problems via the correlation between the magnitudes and characteristics of various elements, and then obtain the design scheme meeting the requirements by extension transformation method.