| Function and cost are two significant attributes influencing profit of automobile company and customers’choice.Excessive function and performance must increase the cost of a product and company may spend too much resource where it cannot meet customers’ requirements.Value engineering method is a good approach to balance the function and cost of the automobile.In this paper,a value engineering method combining with QFD and synthetic weights has been proposed.QFD is used to transfer the customers’ qualitative requirements to a product to quantitative technical characteristics.Then we deploy the technical characteristics to the specific part to identify the part which need to be optimized from the point of value.AHP(Analytic Hierarchy Process)combining with gray relationship analysis is used to calculate subjective weights.PCA(Principle Component Analysis)is used to calculate objective weights.Synthesis of these two parts of weights is the final function analysis weights.Using these synthetic weights,we can calculate the function index and obtain the value index.Applying this value engineering method combining with QFD and synthetic weights to DCT transmission in automobile,we can find the part,dual clutch,which needs to be improved in value aspect.Performance of dynamic,economic,durable and comfortable are connected to the function of dual clutch.7 indexes,including shifting time ts,torque response time of engine te,the largest amount of engine torque vibration△Te,the largest amount of engine rotation speed vibration△ne,gas resumption rate be,the largest amount of acceleration vibration Aa and sliding-friction work W,are used to evaluate the function degree of this dual clutch and obtain its value index.The value optimization from two aspects is performed aiming at the present DCT transmission.One is making alternation among all kinds of clutch plate material.The other is changing the sliding-friction radius of dual clutch.In the end,I have chosen a most excellent solution under this circumstance and increase the value index of this dual clutch in DCT transmission from 0.6395 to 0.8415.Applying this value engineering method combining synthetic weights and QFD we can evaluate the value degree of a product accurately and identify the target field which needs to be improved so that we can find the solution more efficiently. |
