Solid harness keeps wires protected

An automotive wiring harness system that embeds all wires in a stiff composite sleeve has found its first application in a Jaguar concept car. The developer, Beru F1 Systems, says that its ‘Wire in Composite’ (WiC) offers several advantages – most notably an improved robustness, whether to vibration, heat or harsh chemicals. This also makes it attractive to industries such as defence and aerospace. Other advantages include: greater protection; easier serviceability; lower weight; greater design flexibility – as the loom can be made flat, rather than circular; and enhanced aesthetic appearance. For now, WiC has only been proven in the Jaguar C-XF concept car. But Beru is looking to extend the technique this single application. “This has an untold amount of applications,” says John Bailey, managing director of Beru F1. “We are dealing with an aerospace engine manufacturer, as well as Jaguar and some motorsport teams.” Bailey came up with the idea of encasing the wiring loom in a polymer matrix back in the late 1990s, while working at a Formula One team. Since becoming MD of Beru, he has been able to put it into practice – after the company set up its own composites department. “Embedding wires is not very clever in itself,” says Bailey. “The clever bit is the termination of the wires to the connectors.” He says that, when carbon fibre composites are cured, the resins “turn to water” – so must be prevented from getting into the connectors and ruining them. Part of Beru’s ongoing research is to develop a new range of connectors “while staying within aerospace specifications” – which will allow faster production times. There is one potential flaw in the whole concept: if a wire or connector breaks, the entire loom must be replaced – leading to a potentially astronomical service cost. “This is the system’s main vulnerability,” says Bailey. “However, you’d have to try pretty hard to break a connector. One reason we are redesigning the connectors is to improve reliability.” The wires to be embedded are laid within a tool and ‘overmoulded’. Several other processes – which Bailey is unwilling to reveal – are also used before the loom is autoclaved. A ceramic coating can be added for higher temperature resistance. “The shape of a loom is usually dictated by a vehicle or devices,” says Bailey. “This system can be routed into areas that are hot or chemically active.” The technique is very labour intensive and is aimed at niche, high quality cars. In future, the company believes it can scale up production. “Aerospace and motorsport are very low volume – hundreds of units per year – so that’s production-ready,” says Bailey. “Jaguar would like to run it at up to 50,000 units/year. That’s a different world.” Beru hopes to form partnerships with OEMs to look at ways of automating the process. “My vision is that we would licence the technology for higher volume manufacture,” he says. “We are not going to be a mass producer.” For now the aero engine project is still at the pilot stage – but has a design team attached to it. “This is not pie-in-the-sky,” says Bailey. “I hope in two or three years you will see it being used in that industry.” The rest of the defence industry is also a key target for Beru – especially from the ‘robustness’ point of view. “We will have a very big push on tanks and armoured vehicles,” he says. And there is also a promising avenue in F1 – the original source of the idea. Beru will begin a project with “one of the F1 teams” in April, which could lead to WiC being used in F1 cars in the 2008 race season. “An F1 car is a very harsh environment,” says Bailey. “WiC turns the wiring loom into an inert object.” Pointers Wiring harness that embeds wires in a solid composite shell is more robust and easier to service than existing systems It has been used on a single concept car but might later be used in production runs up to 50,000/year