Abstract
Vulcanized rubber hoses are difficult to recycle and have a complicated manufacturing process. Recently, we have developed the vacuum hose for engine control out of thermoplastic elastomers. As a result of this development, scrap material from the manufacturing process can be recycled and, in addition, about a 30 percent weight reduction and a 20percent cost reduction are achievable by virtue of the lower specific gravity and by the more simplified manufacturing process.
In order to assess the feasibility of using thermoplastic elastomers for vacuum hoses, we developed a heat aging simulation test method. This was achieved by first investigating the actual vehicle environmental conditions of currently used vacuum hoses by retrieving and examining these hoses from used vehicles. We then extrapolated what the condition of such hoses would be after being subjected to heat aging for 200,000 km of service in an actual vehicle, and applied this calculation to our newly developed hoses. We compared the life span of the new thermoplastic elastomeric hose with that of the current rubber hose by using the Arrhenius equation, and as a result, we could verify that the new hoses are usable in actual vehicles.