Hoses prevent damage caused by biodiesel fuel

  • 02-Oct-2008 10:51 EDT
Hoses formulated specifically for biodiesel fuels can withstand higher temperatures and higher percentages of biodiesel than traditional hoses.

The growing adoption of biodiesel fuels, combined with the increasing percentages of biodiesel in those blends, is prompting changes in many conventional engine components. Among them are hoses, which must be reformulated to withstand biodiesel properties.

Eaton Fluid Power Group has rolled out its GH100 line of hoses designed for applications that have 20% biodiesel or higher percentages and/or operating temperatures above 120°C (248°F).

At temperatures over 100°C (212°F), some biodiesel blends above B20 can “bake out” the elastomers that keep hoses flexible. This situation is particularly problematic in vehicles that may see a variety of fuel blends, B5 in one tank and B20 or higher in the next fill up.

“If hoses aren’t compatible with biodiesel, they may swell or soften,” said Doris Showalter, Senior Product Manager for Transportation Products, Eaton. “These fluids can quickly make ordinary hose products brittle and prone to cracking.”

The need for biodiesel-compatible hoses is expected to increase quickly. Caterpillar, Deere, Cummins, Volvo, and others have announced B20 projects in response to higher fuel prices and a growing effort to trim emissions. “Biodiesel can reduce emissions by as much as 16%,” said Showalter.

GH100 hoses feature a hydrogenated nitrile rubber tube, which is resistant to damage caused by the various materials used to make biodiesel. They are qualified for underhood use with B2 to B20 up to 150°C (302°F) and B100 up to 125°C (257°F).

Beyond temperature, changing percentages and the multitude of materials added to conventional diesel fuel make it difficult to determine what type of hoses are needed. “Biodiesel blends change continuously,” said Showalter. “If you’re using B2 to B5 and have temperatures around 100 to 110°C, existing hoses are fine.”

The hoses are also designed for use with synthetic lubricants used in high-temperature truck transmission oil cooler applications. In this application, peak temperatures go up to 175°C (347°F).

An aramid/poly braid reinforcement and a polyester abrasion-resistant cover were used to ruggedize the hoses. They are fully compatible with industry-standard threaded fittings and formed tubes and Eaton’s threadless STC connectors.

“The initial product offering will include sizes 6 through 12. Other sizes can be produced to meet specific customer requirements,” said Showalter.

The new hoses bring a mild pricing premium over conventional hoses. However, Showalter noted that premium is below the cost of other alternatives.

“This is 10 to 12% higher than CPE hoses, but it’s still less expensive than Teflon. Customers wanted something that’s more flexible than Teflon, which is very stiff,” she said.

She also noted that higher ratios for biodiesel will require metal tubing.  “When you’re going up to B100, stainless steel should probably be used.”

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