Uno de los fabricantes punteros de estos temas es Dupont.
https://www.dupont.com/knowledge/performance-polymers-solutions.html
EGR Seals, Hoses, Valves, Bushings and Gaskets
EGR systems, designed to reduce oxides of nitrogen (NOx) from exhaust emissions, recirculate already combusted exhaust back into the air intake to dilute the incoming air/fuel mixture, thus reducing combustion temperatures well below the 1300+°C peak at which NOx is formed. However, recycling exhaust gases back into the engine results in gas compositions that are very aggressive to many sealing elastomers.
Vamac® ethylene acrylic elastomers and Viton® fluoroelastomers are at the forefront of developments in flexible hoses and hose-end seals, providing long-term temperature and acid resistance for these key EGR applications.
Vamac® provides a cost-effective EGR hose and sealing solution at peak temperatures up to 150°C, while Viton® can be considered the primary candidate for highly concentrated acid environments at peak temperatures up to 225°C.
EGR Valve Bushings of DuPont™ Vespel® Parts at Gustav Wahler
In rigid EGR applications, valve bushings of Vespel® TP polyimide have replaced metal components because of its stiffness, tensile strength, and resistance to friction, wear and hot exhaust gases at temperatures up to 220°C. The valve bushings, made by Gustav Wahler GmbH and Co. KG of Esslingen, Germany, for an EGR system used in four and six-cylinder stratified-charged petrol engines, position and guide the cylindrical operating rods of EGR slip-in valves, supporting their smooth operation during millions of openings and closings.
Low wear, low friction injection molded bushings of Vespel® TP polyimide for EGR valves manufactured by Gustav Wahler for four and six cylinder petrol engines, offer increased design freedom, reduced weight, elimination of contact corrosion and increased resistance to aggressive exhaust gases when compared to similar metal bushings.
¿Alguien sabe lo que montan los motores Diesel de Volvo de 2 o 2,4 litros?
Vamac soporta temperaturas de hasta 150 grados
Viton de hasta 225 grados
Vespel de hasta 220 grados
Seguimos investigando ;-)