A novel optimization methodology of modular wiring harnesses in modern vehicles: weight reduction and safe operation
- Autores: Armand Rius Rueda
- Directores de la Tesis: Antoni Garcia Espinosa (dir. tes.), Jasmina Casals-Terré (tut. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2017
- Idioma: español
- Tribunal Calificador de la Tesis: José María Maza Ortega (presid.), Jordi-Roger Riba Ruiz (secret.), Theodoros Kosmanis (voc.)
- Programa de doctorado: Programa de Doctorado en Ingeniería Mecánica, Fluidos y Aeronáutica por la Universidad Politécnica de Catalunya
- Materias:
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- Resumen
The weight of electric and electronic components of cars has been uninterruptedly increasing through the last decades, and thus the weight of their wiring harnesses. This fact has awakened the interest of car manufacturers on the weight and cost optimization of automotive wiring harnesses . For this reason, this dissertation discusses and develops approaches to reduce the amount of copper for the purpose of current conduction, i.e. the cross-sections of all of the wires of the car, without endangering safety.
On the one hand, harnesses must withstand continuous operation currents. On account of this, it is necessary to know the characteristic flow of current of the in-vehicle electrical network. Nevertheless. the huge quantity of available combinations of equipment of the car produces a proportional variety of customer-specific wiring hamesses, and makes it unfeasible to simulate all of them. This thesis points attention on specific segments of the wiring harnesses. Sorne of them can have many possible compositions, which are related to the customer's car settings. Since computation time is a limiting factor here, it is proposed to predict the bundle heating behaviors by means of response surfaces, obtained from a set of finite element simulation results and the least squares method.
On the other hand, the correct wire sizes must ensure that they are protected by their associated melting fuses, so that their maximum acceptable temperature is not exceeded after short circuits. Since many wires in cars are connected to other wires with splices, or may suffer short-circuits in their electric loads, these short-circuits can flow across different wires. In modular wiring harnesses, each of the wires can have different lengths and different installation ratios, their cross-section affects the cost of the wire harness with different importance, as well as the short circuit and the final temperature of the wire. The finite volume method is used to simulate the short circuit of series-connected wires. Finally, non-linear optimization is used to find the mínimum cross sections of wires respecting the constraints of maximum temperature and mínimum short-circuit current.
Finally, these two different criteria for optima! wire dimensioning are combined in the analysis of the on-board network of the vehicle in order to make a complete weight and cost minimization of the cable harnesses in a particular vehicle, considering also its modularity of loads.
