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Optimisation of the cable harness

Scientific investigations and practical measurements for the selection and optimisation of the layout of cable harnesses, fuses and other electrical components in cars.

Over recent decades, the number and weight of electrical conductors in cars has increased dramatically. Nowadays, a top class car has more than 3 km of cables with a mass of more than 40 kg. Compared to the whole mass of a car, this is more than a tolerable increase. This rise is expected to continue in the future. This trend requires space as well as a noticeably increase in the weight of a car. Proposals and attempts have been considered to counteract this trend, e.g. increasing the supply voltage to 42 Volts or more. However, the most obvious measure would be a careful consideration of the actual cable harness and its protection against unintended high currents (including short circuits). At present, the wires for the cable harness for mobile application are still selected according to design rules and specifications elaborated for stationary use and not necessarily suited for mobile application. For this kind of application, completely different rules would be valid. In a passenger car for instance, the cable length would not exceed 8 metres and is in most cases even considerably shorter. Power and voltage losses due to higher use of its capacities would not count as much. On the other hand, the way of placing the various cables or cable bundles in a car body structure, sometimes in foam, in special tubes or cable channels, as well as the temperature of the environment, require more care given the thermal situations. To be on the safe side, the wire cross sections are oversized in most cases. In addition to this, another safety margin is normally added in order to comply with the widespread breakthrough characteristic of the thermal fuses. This is why several car companies initiated a research and development programme with the aim of optimising the cable harness on the basis of precise physical considerations and mathematical calculations, and encouraged the cable, cable harness and fuse manufacturers to join this work. For the above-mentioned reasons, it is of great interest to mathematically model the thermal behaviour of cables, cable bundles and fuses under continuous and interrupted load conditions at the various environment temperatures, which are typical for applications in cars. By using such modelling, it is possible to identify the characteristic physical parameters of these components and show that this calculation is precise enough in the temperature range of interest for practical applications. The aim of this project is to use the calculation results of the preparatory work as a basis for the development of an industrial applicable mathematical algorithm for the design of the various elements of the power distribution in vehicles, especially in cars. This would allow for predicting the thermal behaviour of the applied components and would avoid carrying out too many experiments to verify these relationships. The data and algorithm produced, on which this data is based, should be later integrated into the relevant development tools for car manufacturers and cable, cable harness, and fuse producers. The results should be proposed for European standardisation in this area. The numeric of the mathematical models mentioned cannot be solved by the programme packages using standard methods, since the available software is not applicable for these particular industrial routine calculations. For this reason, it is very important to develop new numerical algorithms for mathematical models of cable bundles and fuses. It is also highly important to verify the experiments by measuring the physical parameters of cable bundles and fuses in real cars. This action would help to validate the recently developed analytical and numerical algorithm. Keywords: thermal behaviour, wires, fuses.
Acronym: 
OPTCABLES
Project ID: 
3 691
Start date: 
01-01-2006
Project Duration: 
63months
Project costs: 
1 520 000.00€
Technological Area: 
Design and Modeling / Prototypes
Market Area: 
Motor Vehicles, Transportation Equipment and Parts

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