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Viton® Shrugs Off Cold and Heat in Japanese Direct Injection Engines

To purchase Viton® o-rings and seals, call Problem Solving Products at (303) 758-2728.

News Release from Dupont Dow Elastomers

5/21/2001

Higher fuel efficiency has become the major goal of today's advanced engine technology as global exhaust emission regulations tighten. And recent developments in direct fuel injection have enabled automotive engineers to accomplish lower and cleaner fuel consumption in pursuit of the goal.

Viton® o-rings are used in modern automotive fuel engine systems. While the automotive industry in Europe has recently focused more on diesel engine technology, the Japanese industry has played a significant role in developing direct injection technology for gasoline engines. Between 1996 and 2000, Mitsubishi, Nissan and Toyota introduced some 34 car models with such engines. Direct injection gasoline engines are now projected to take 40 percent of the market in Western Europe, 25 percent in Japan and 10-15 percent in the US by 2005.

The consequences of failure

Both engine technologies use the same concept of injecting an optimum air-fuel droplet mixture directly into the combustion chamber to achieve high burn efficiency, minimize particulates in the exhaust gases and enhance power output. To do this, the latest high-pressure fuel pumps and injectors are designed to create such conditions by producing minute "ideal" fuel droplets.

These fuel pumps and injectors operate under pressures from 5MPa to 13MPa and are fitted with several O-rings to prevent leakage of fuel into hot engine compartments. The operating conditions are tough on sealing materials. O-rings must be capable of sealing from as low as -40°C to as high as +150°C, and be highly resistant to aggressive automotive fuels. Even higher temperatures can be reached in the event of a cooling system failure or simply due to heat peaks when the engine is turned off and coolant is no longer circulating. The consequence of O-ring failure in such environments could be catastrophic.

Complete confidence

Automotive fuel system specifiers must have complete confidence in the integrity of seals in this critical application. Reports from the Japanese automotive industry confirm that O-ring seals of DuPont Dow Viton® fluoroelastomers are being increasingly selected for fuel injector and high pressure pump systems supplied to manufacturers such as Mitsubishi, Nissan and Toyota.

DuPont Dow Elastomers has developed several types of Viton® for modern fuel management systems. Among these, Viton® B-70 was specifically designed to provide a good balance of low temperature performance and fuel resistance for fuel injector Viton® O-ring applications.

Viton® GLT is superior in low temperature sealing and can perform comfortably at -40°C in a dry seal test. Fuel injector O-rings of Viton® GLT are used for both indirect and direct injection engines and in high-pressure fuel pumps for direct injection systems. This fluoroelastomer type is most frequently specified to meet stricter product liability requirements in cold climate markets.

In response to growing demand, DuPont Dow Elastomers recently commercialized two new improved processing grades - Viton® GLT-305 and GLT-505 - to simplify injection and compression molding. In addition, the company announced Viton® VTX-9136 offering the same low temperature properties as Viton® GLT but with the easy processing advantages of conventional bisphenol types of Viton®, to provide extremely low mold fouling and part reject rates.

About DuPont Dow Elastomers

DuPont Dow Elastomers, a global supplier of specialty elastomers with headquarters in Wilmington, Delaware, USA, is a joint venture between the DuPont Company and The Dow Chemical Company, with more than $1 billion (USD) in sales. The company is the industry leader in chloroelastomers, ethylene elastomers and fluorinated elastomers, serving the automotive, chemical processing, construction, general rubber and wire and cable industries.

To purchase Viton® o-rings and seals, call Problem Solving Products at (303) 758-2728.

News Release: Viton® Shrugs Off Cold and Heat in Japanese Direct Injection Engines

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Viton® is a registered trademark of DuPont Dow Elastomers.