Federal-Mogul says it has developed an innovative new crankshaft seal design, called MicroTorq that reduces friction by up to 70 percent versus conventional lip-type seals. They claim that this will result in an improvement in vehicle fuel economy of up to 0.49 percent and a reduction in CO2 emissions of 1-2 g/km compared to traditional seal designs.
"MicroTorq seals can offer an immediate CO2 savings of 1-2 g/km on current engine applications and up to 3.5 g/km for new engine development with almost no additional cost," said Gerard Chochoy, senior vice president, Federal-Mogul Powertrain Sealing and Bearings. "That's a big opportunity for Federal-Mogul customers using combustion engines in their vehicles or power generation applications."
Friction occurs because conventional lip seals are preloaded against the crankshaft to maintain sealing when the crankshaft moves within the bearing clearance under varying load conditions. As well as consuming energy, friction at the seal's lip creates heat that degrades the oil, causing a build-up of carbon that destroys the hydrodynamic function of the seal lip, leading to oil leakage. With an engine running at 2000 rpm, this friction can account for up to 3.5 g/km of a vehicle’s CO2 output when a pair of conventional crankshaft seals is used.
The MicroTorq seals have a ‘dual-hinge’ design that allows the main sealing element to maintain uniform contact with the shaft under conditions of varying geometry while maintaining a light contact load at both the main lip and the dirt excluder lip. Additionally, unique hydrodynamic features molded into the seal are shaped to efficiently pump oil back into the engine while the crankshaft is turning, and provide static sealing when it is not. The engine itself can also be more compact and lightweight as the packing of the MicroTorq is less than 5mm as compared to the traditional 7-10mm.
"By adopting a fundamentally new design approach, we have developed a family of low friction seals that offer vehicle manufacturers a simple, cost-effective and easily implemented route to reduced emissions and improved fuel economy," said Larry Brouwer, Director, Sealing Technology and Innovation, Federal-Mogul Powertrain Sealing and Bearings. There are very few technologies that offer such an affordable route to CO2 reduction, making this an extremely attractive solution for all vehicle manufacturers."
These seals are easy to install without changing the design of adjacent components, require less package space, and are more accommodating of shaft misalignment. With proven fuel consumption improvements of up to 0.49 per cent and lower CO2 emissions of up to 3.5 g/km, this is another example of technology on small scale that is simple and has an immediate impact on our pocket books and our carbon footprint.