Automotive silicon hoses and silicon hose connectors
Automotive silicon hoses and silicon hose connectors – general information
Hoses and moulded connectors used in cars and construction machinery for the transfer of water, air, oil, fuel and many other working fluids. Used in cooling installations, Turbo systems, tank supply, in venting systems.
Made of silicone or rubber: EPDM, NBR, NBR/PVC, CR, AEM (ethylene – acrylic rubber). Reinforced with braid or cord made of polyester fibre, aramid fibre, Nomex fibre or glass fibre. Working pressure up to over ten bar, working temperature may exceed 300°C – depending on material, hose wall thickness and number of reinforcement layers. Shaped as hoses, straight or angle connectors, reducers or elbows.
Characteristics of hose assembly systems in vehicles:
- very compact arrangement of the elements of various systems resulting from limited space, forcing the use of hoses with a small bending radius, customised fittings, and in many cases, elements specially moulded for a given place in the vehicle;
- extreme and rapidly changing temperatures due to weather, radiation and heat conduction (under-hood temperatures can reach up to 100°C);
- continuous vibration due to powertrain operation and vehicle movement;
- external exposure to fuel, oil, grease, operating fluids;
- difficult monitoring of the technical state of system components because of their tight layout.
All of these technical factors should be taken into account when selecting a hose, with additional consideration given to the requirements of applicable standards in a particular field, e.g. flame retardancy or toxicity of combustion products.
Moulded connectors and hoses
In many cases, a lack of space is a major reason preventing the use of a general purpose hose or connector in vehicle construction. Then, special moulded connectors are used, intended for a specific location in a given type of vehicle, made of various materials: silicone, EPDM, NBR, CR, AEM (ethylene-acrylic rubber), with different construction and reinforcement (polyester, aramid or glass fibre, steel helix).