Over 10% of buses operating in the US are now powered by natural gas and carbon fiber reinforced CNG cylinders are the likely candidates. Light duty vehicles are generally fitted with two or three pressure vessels, whilst heavy duty vehicles tend to be fitted with four to six. The cylinder types are classified:
- Type Ⅱ-metallic vessel body with composite hoop strap (generally fiberglass)
- Type Ⅲ-metallic liner with full composite overwrap (mainly carbon fiber)
- Type Ⅳ-all composite construction (mainly carbon fiber)
All composite construction CNG vessels are made by IMPCO technologies, Lincoln composites and Quantum technologies worldwide in the US and MCS cylinder systems GmbH and Ullit in Europe.
Dynatek industries manufactures cylinders for CNG powered vehicles using carbon fiber/glass composite, offering great saving for transit buses. They are used for the Ford Focus fuel-cell vehicle.
Du Vall compares the cost of wet filament winding versus prepreg filament winding for Type Ⅱ and Type Ⅳ CNG cylinders and Funck discusses high pressure vessels for compressed gas.
Lincoln composites manufacture a range of on board vehicle tanks for CNG. The tanks are made by overwrapping a polymeric liner such as polyethylene with a composite and a hybrid mix of glass and carbon fiber is used to improve impact resistance.
Dynatek industries, based in Clgary, has found it advantageous to use a selected heat treatment to Al liners to provide higher strength and then overwrapping with high strength carbon fiber.
A conformable tank has been developed by ATK Thiokol propulsion co. for on-board storage of H2 for fuel cell vehicles, comprising of a polymer lining, a carbon fiber inner layer and an impact resistant outer layer.
America Technical Center has used a seamless metallic liner overwrapped with carbon fiber for storing 5000 psi hydrogen in a fuel cell.
Motor bikes: Synergy Motorsports have introduced the first carbon fiber chassis for a motocrosser, with the weight saving enabling a 4-stroke engine to be fitted and the weight of the motorcycle is less than that of a comparable 2-stroke machine. Carbon fiber was used for the frame, saving-arm, cradle, air box and several protective covers.
Britten, a New Zealand motorcycle company, has used a composite subchassis made of carbon fiber/Kevlar Drakane epoxy vinyl ester resin laminate for their Britten V1000 racing machine. The Aprila 250 uses cfrp wheels molded in two halves from a 2-2 HS twill weave fabric. HiPer Technology use carbon fiber reinforced nylon for their motocross vehicles.