There are few more aggressive environments in motorsport than the inside of an F1 fuel tank. Components within these vessels are immersed in volatile racing fuel and subject to cornering forces of up to 3.5G, as well as intense vibrations from engine components that spin at up to 19,000rpm during racing. They face an even bigger test during refuelling at pit stops, when a new fuel load is blasted into the tank at speeds of up to 12 litres per second. Ensuring that the electronics that control the submerged fuel pumps and level sensors can operate reliably in these conditions is a significant challenge. Total reliability is imperative too as, sealed in the flexible polymer tank liner, there is little chance of repairing or replacing these components during a race weekend.
Norfolk-based motor sport technology specialist Beru F1 Systems has substantial experience in the delivery of robust wiring systems to the F1 industry (see DPA September 2006 page 15). The company is currently enhancing the performance and reliability of connectors in the critical fuel tank environment by potting them in an advanced epoxy compound from 3M.
"Because inspection of the connectors in the fuel tank is so difficult, we need to do anything we can to minimise the risk of failure," explains Gary Norman, principal engineer at Beru F1 Systems. "We use 3M materials a lot in harness construction and they are our first port of call when we have a problem to solve. In this case, we identified DP490 as an ideal solution."
DP490 is a filled structural epoxy adhesive. It offers one of the best combinations of high strength and toughness in the 3M EPX structural adhesives range, and combines high bonding performance with gap filling abilities and ease of working.
"Although DP490 is designed as an adhesive rather than a potting compound, we found that its superior strength and toughness, combined with the easy mixing and dispensing through the 3M Duo Pack system gave us exactly the right properties for the job," says Mr Norman.
Connectors sealed with DP490 have been run in several major race series to date, including F1 racing and the Le Mans Endurance Series. To date, there have been no connector failures in use.