Cable harness is an integral part of a modern-day automobile. The design of many mechanical components is based on the cable harness and hence it is important to accurately calculate the space occupied by cable harness. In this thesis, a theoretical model representing n arbitrarily sized cables was used to generate a packing of the cable harness, and the space occupied by them was calculated. The model was used to develop an algorithm that generated a feasible configuration and a container around that packing. The optimisation toolbox in MATLAB was also used to calculate the space and optimise the container size. A customised standalone tool was developed in MATLAB by utilising the established methods, that enables calculation of space occupied by cables at various points of interest along the truck chassis for Scania CV.

This semestral paper deals with the issues of testing and requirements examinations for cables and cable harnesses. These terms are defined in the work and the difference in their meaning is described. The work also describes the characteristic features of cables and cable harnesses, explains their importance and focuses in more detail on the variable properties that may change over time or that are dependent on manufacturing errors. The principles and procedures of tests of these properties are covered in the work and are the essence of the subsequent practical part. In this part, the work deals with the design of the measuring circuit prototype for testing of the insulation resistance of cables and their desired continuity in bundles. This design is then physically implemented, the processes of designing and implementing are described in detail and finally its functionality is tested and presented to the reader.

Dans le contexte de la montée des préoccupations écologiques, le développement de véhicules de transports routiers s’oriente vers le développement de véhicules moins polluants à entraînement électrique comme les Véhicules Électriques Hybrides (VEHs) et les Véhicules tout Électriques (VEs). Avec l’augmentation des puissances requises et la réduction de l’espace disponible, la gestion thermique devient une préoccupation de plus en plus importante lors du développement des composants embarqués comme les moteurs/générateurs électriques, onduleurs, batteries et faisceaux électriques. Parmi eux, le faisceau électrique de puissance qui est typiquement composé de câbles électriques, de connecteurs et de boîtes de distribution de puissance ne peut être conçu de manière appropriée qu’à la suite d’une analyse thermique, électrique, chimique et mécanique approfondie.Cette thèse est écrite pour contribuer à l’optimisation de la conception électrothermique de faisceaux de câbles par des simulations afin de réduire la quantité de tests expérimentaux nécessaires pour leur développement. Des modèles théoriques pour la prédiction du comportement électrique et thermique de câbles électriques et des faisceaux de câbles sont passés en revue et adaptés aux exigences automobiles. La validation est accomplie en comparant les résultats de simulation avec ceux d’analyses élément finie (FEA) et de données de mesure. Une partie majeure de cette thèse aborde la simulation thermique de câbles électriques de longueur infinie suspendus dans l’air, prenant en compte les dépendances en température des résistances de conducteurs et la non-linéarité du coefficient de transfert thermique total à la surface du câble. L’influence des courants de blindage et de courants arbitraires dans les conducteurs sur la montée en température des câbles électriques est considérée dans des circuits thermiques équivalents et illustré par des exemples pratiques. / In the context of growing ecological concerns, the development of road transport vehicles moves itself toward the development of less polluting vehicles with electric drives such as Hybrid Electric Vehicles (HEVs) and full Electric Vehicles (EVs). With rising power requirements and reducing available space, thermal management is becoming an increasingly important concern during development of on-board vehicle components such as electric motor(s)/generator(s), power inverter(s), battery pack(s) and cable harnesses. Among them, the cable harness which is typically composed of electrical cables, connectors and power distribution boxes can only be designed properly after a detailed thermal, electrical, chemical and mechanical analysis.This thesis is written to contribute to the optimization of the electro-thermal design of cable harnesses through simulations and reduce the amount of experimental testing needed during their development. Theoretical models for the prediction of the electrical and thermal behavior of electric cables and cable harnesses are reviewed and adapted for automotive requirements. Validation is accomplished by comparing simulation results with Finite Element Analysis (FEA) and measurement data. A major part of this thesis addresses the thermal simulation of electrical cables of infinite length installed in air, taking into account the temperature dependencies of conductor resistances and non-linearity of the total heat transfer coefficient at the cable surface. The influence of shielding currents and arbitrary current loads in the conductors on the temperature rises within electric cables is also considered using thermal ladder networks and illustrated by practical examples. Because shielding currents in vehicles are not only caused by induced currents but also by functional electrical currents generated by low-voltage power sources, new theoretical studies and experimental observations for the estimation of these currents as a function of the vehicle electrical architecture and circuit characteristics are presented. A primary finding reveals that keeping the resistance of grounding connections low compared to that of the shielding connections is an appropriate but expensive means for limiting the transfer of functional currents in the shielding circuits. Finally, a complete and modular model for the prediction of transient temperatures along the length of cable harness sections is developed and validated based on the outcomes of all previous findings.

In the highly competitive transportation industry, one way to gain a competitive advantage is to ensure the customer needs are satisfied and tailored according to each customer’s need. Scania’s one of the core values is customers first and believes that the organization is successful only when its customers are successful. In order to achieve their goals, modularization is the key to tailoring the needs of each customer. Considering this factor, an ‘n’ number of variants are required in each module of the trucks and buses offered to the customer. This thesis focuses onthe high voltage cables i.e. VCB cables in Scania’s terms, the cable harnesses are considered as the human nerves and blood vessels for automobiles. Scania is set to produce the VCB cables in-house instead of buying them from the suppliers which is the current method. The thesis focuses on the challenges in change management for new components in-house manufacturing by design-manufacturing integration as a solution. A case study is conducted for the products of electric trucks and buses to understand the design manufacturing integrations. The thesis aims to identify gaps and find where the highest risk exists for deviations in today’s process in terms of design demands, product specification, and product preparation in the production of VCB cables. The case study is conducted, including a literature review and semi-structured qualitative interviews to understand the workflow of how the information is transferred between many cross-functional groups with different business areas such as research & development (R&D) and production. The thesis aims to understand what challenges Scania’s METP (Engineering and process, Battery & VCB production) production group faces while going through a change of organizational structure and interpreting the information via engineering drawings between different stakeholders/groups. A conceptual framework is presented by emphasizing the communication between the R&D groups and the production group by benchmarking the DMI practices for collaborative product development. Furthermore, suggestions for effective drawing methods and increasing the group dynamics between R&D and production are discussed in the thesis. It is hoped that the thesis provides a guide to initiate the stated tasks in results to ensure a smooth production start-up. / I den mycket konkurrensutsatta transportbranschen är ett sätt att få en konkurrensfördel att säkerställa kundens behov genom att skräddarsy produkten efter varje kunds behov. En av Scanias kärnvärdena är “kunderna först” vilket Scania anser vara ett viktigt måtto, speciellt eftersom Scanias framgång bygger på kundens framgång. För att nå sina mål är modularisering nyckeln till framgång. För att lyckas med detta krävs ett "n" antal varianter i varje modul av de produkkter som erbjuds kunden. Detta examensarbete fokuserar på högspänningskablarna. Scania utforskar möjligheten att producera högspänningskablarna i egen regi istället för att köpa dem från leverantörerna, vilket är den nuvarande metoden. Avhandlingen fokuserar på utmaningarna inom förändringsarbetet som krävs för att impementera denna typ av förändring. En fallstudie genomfördes på elektriska lastbilar och bussar för att förstå integrationen av design och tillverkning på detaljerad nivå som tidgare inte hade behövts eftersom externa leverantör tog hand om detaljerna. Avhandlingen syftar till att identifiera luckor och hitta var den största risken finns för avvikelser i dagens process vad gäller designkrav, produktspecifikationer och produktförberedelser vid tillverkning av högspänningskablage. Fallstudien genomfördes, inklusive en litteraturgenomgång och semistrukturerade kvalitativa intervjuer för att förstå arbetsflödet för hur informationen överförs mellan tvärfunktionella grupper. Dessa grupper har olika affärsområden såsom forskning & utveckling (FoU) och produktion. Avhandlingen syftar till att förstå vilka utmaningar Scanias production team (Engineering and process, Battery & VCB production) produktionsgrupp står inför samtidigt som de går igenom en förändring av organisationsstrukturen och tolkar informationen via tekniska ritningar mellan olika intressenter/grupper. Ett konceptuellt ramverk presenteras genom att betona kommunikationen mellan FoU-grupperna och produktionsgruppen genom att jämföra DMI:s praxis för samverkande produktutveckling. Vidare diskuteras förslag på effektiva metoder för teknisk ritning samt att öka gruppdynamiken mellan FoU och produktion. Förhoppningen är att avhandlingen ger en vägledning för att initiera de angivna målen för att säkerställa en smidig produktionsstart.