RTP silencer cuts-out turbo whine for VW

APPLICATI#&$ RTP silencer cuts-out turbo whine for VW REINFORCED thermoplastics continue to prove that they are often the best material for application in hostile under-thebonnet conditions. Zytel HTN nylon from DuPont is being used to make silencers which reduce turbo-charger whine on VW diesel engines. The broad-band Zytel silencer lowers the turbocharger’s noise level by up to 30 db in the lOOO5000 Hz range, while operating reliably at high temperature and withstanding severe environmental influences during use. Nenad Cvjeticanin, the materials selection engi-

standing dynamic stresses created when the engine starts up, when the load on it changes or when the vehicle accelerates. Moreover, it had to resist many types of aggressive media, including oil mist, road salt and sprays of water. In laboratory tests Zytel with 35% glass fibre reinforcement was found to be the best choice, offering higher resistance to salts than conventional PA 66 and PA 6 grades.

Silencers made from glass reinforced nylon are reducing annoying turbcxbarger whine on VW diesel engines.

neer at parts maker Franz Josef Wolf, says that to ensure the silencer remained fully operational for the working life speci-

Nenad Cvjeticanin, WOCO Franz Josef Wolf & Co; tel: + 49-6056- 7813 1; fax: f 4P 6056- 78607; Jill Lucius, DuPont Automotive; tel: + 1-248583-81 12.

fied by VW, it had to be able to work at temperatures anywhere between -40°C and 175°C. It also had to capable of with-

Isopolyester still best for petrol tanks ISOPOLYESTER resin still offers the best cost/performance balance for composite underground storage tanks, according to resin maker Alpha Owens Corning (AOC). The US company is responding to suggestions that the petroleum industry should switch to non-isopolyester resin for tanks to hold new fuels designed to reduce emissions. The fuels blend petrol with ethanol, methanol and/or methyl tertiary butyl ether (MTBE). “The first Underwriter Laboratory-approved underground fuel storage tank was specified in isopolyester 30 years ago,” says Jack Roesle, vice president of global sales and marketing for AOC. “Since then, there have been no known reports of failure from a UL-approved iso-

Reinforced

Plastics November

polyester petrol storage tank as a result of chemical attack. With the improved resin formulations available today, isopolyesters can provide even better performance to the petroleum industry for all approved fuels.” AOC’s scientists are confirming this with a research programme. Initial results indicate that unsaturated polyester resins made with purified isophthalic acid (PLA) from Amoco Chemical, offer performance benefits over non-isopolyester grades. A study Amoco commissioned from Dutch research institute r TN0 in 1992 also shows that highly cross-linked isopolyester offers the required fuel resistance at a lower cost than vinyl ester or more expensive unsaturated polyester resins.

1997

Complete set of production moulds for the fabrication of polyester units, to be used as: l

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Dimensions:

8 ft. 4 inches

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Height:

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This product is protected by European patent

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