Multi-Objective Evaluation Regulation Study of Automotive Lightweight

Abstract

Based on the multi-objective optimization and design of automotive body, the evaluation method of automotive lightweight is studied. An innovative evaluation method and the automotive lightweight comprehensive evaluation index E are presented, which is expressed by following formula \( {\text{E}} = \frac{{{\text{m}}_{{{\text{body}}}} }}{{{\text{C}}_{{\text{t}}} \, \times \,{\text{A}}\, \times \,\left[ {{\text{ENCAP}}} \right]\, \times \,{\text{F}}}}\left[ {\frac{{{\text{kg}}}}{{{\text{Nm}}/^{^\circ } \, \times \,{\text{m}}^{2} \, \times \,{\text{Hz}}}} \times 10^{4} } \right] \) , and the weight of car body is associated with the model, stiffness of car body and safety of cars by this formula. The relationship between automotive lightweight and correlative functions is discussed. The evaluation method is confirmed by applying the data of 14 typical passenger cars. The relationship between evaluation index E and relational parameters are discussed, and some comparison and analysis are carried out, the sensitivity of E value for varying of relational parameters values is demonstrated, and the sensitivity is acceptable. And according to the E value, the lightweight level of a car can be defined, which is from 1 to 5 stars. A requirement of integrated fuel consumption for lightweight star level based on car mass is presented to be as a modifier to modify the final star-rating results of a car. This evaluation regulation considers the modal, stiffness, and sizes of car body, and safety of cars, and fuel consumption which are associated with weight of car body and car mass. A conclusion is attained that the evaluation method of lightweight presented by this paper is feasible, however, the details of evaluation regulation of automotive lightweight will be studied further, and an official new car evaluation regulation of automotive lightweight will be presented. According to the evaluation results and stars rating, customers can choose to buy a more lightweight and energy-saving car. And based on the stars rating, governments can also improve energy saving and emission reduction of automotive industry, by encouraging the car makers which produce the lightweight cars.