Air intake seals from ITW Southland meet LEV II
Air intake manifold with gasket of Viton®
Increasingly stringent regulations are pushing automotive evaporative emission limits beyond the capabilities of many sealing materials. Consequently, fuel system and engine sealing OEMs have been searching for next generation materials with fuel permeation performance to meet LEV II and PZEV regulations and Euro 4 requirements.
ITW Southland of Virginia Beach, USA, a leader in automotive engine sealing, has found such a material — Viton® fluoroelastomer (FKM) from DuPont Performance Elastomers.
The company has commercialized an air intake manifold gasket of Viton®, already installed in over 250,000 automotive engines. ITW Southland selected Viton® following extensive testing of alternative sealing materials and other fluoroelastomers, finding that Viton® offered superior permeation resistance to meet or exceed all current evaporative emission requirements for air induction systems.
Air intake manifold gaskets being molded at ITW. "The general industry perception is that it is tougher to fill mold cavities with FKM, but not so with Viton®," says Tesky.
"Although the industry benchmark was silicone, its permeation resistance is extremely poor. While HNBR is better than silicone, we needed a gasket seal material that would comply for at least 15 years/150,000 miles of vehicle life to meet LEV II and PZEV requirements. That's a tough order. But FKM is in a whole different league — that's why we chose Viton®," says Mark Conlee, Technical Director at ITW Southland.
But compliant end-use performance was not the only consideration. Processability was key to achieving cost-effectiveness through ITW Southland's highly automated injection molding process.
"Our goal was to run Viton® at the same production rate and cavitation as a silicone tool. We found that it processed very well and there is no doubt that the fluoroelastomer fulfilled our needs best versus HNBR and silicone. It was also the only seal material that could meet the emission requirements put forth by the OEMs," says Todd Tesky, Technical Sales Manager.
"ITW is demonstrating to other OEMs that sealing products of Viton® represent a very cost competitive solution that parallels HNBR prices via technology and automation," says Tesky.
"I like the way Viton® runs. It offers a good blend of processability, cures very tight and consistent, and we have developed an optimal formulation that works very well with robotics. In over 6 months, we've had no sticking or mold fouling issues. It will take a big argument to make me change," adds Mark Conlee.
ITW Southland employs an unusual degree of robotic automation, enabling the company to eliminate labor, exceed human quality inspection capabilities, and compete head on with gasket production from China.
"Through technology and robotic loading and unloading of equipment, vision inspection with cameras, and automated leak testing, ITW is raising the bar in quality. It's opening doors for us," comments Tesky.
ITW is now applying what it has learned with Viton® in air intake gaskets to develop applications like fuel sender seals, throttle body gaskets, and other under the hood fuel delivery system components.