By Marlee Rosen, Rosen Associates
The automotive industry has looked upon motorsports-borne technology as a great test bed for new development and innovations for road cars. By applying lessons from the track to the road in helping to develop new hardware, systems and equipment that power and protect motorists globally, it can be easy to understand how the smallest of parts (seals, bearings, rings, diaphragms, etc.) have to be evaluated and quite often re-engineered to work with the automotive industry’s constantly evolving cars systems and parts.
For instance, there are often releases of the next best turbochargers that run hotter and actually have an unintended impact on the materials used in that charger like seals and bearings. Turbochargers use plain bearings lubricated with oil under pressure from the engine’s oil pump. The bearing is in the middle of the turbocharger, between the intake and exhaust sides. Additionally there are two oil seals, keeping oil from escaping from the bearing residing on the intake side and the other on the exhaust side.
According to Ray Gillies, General Manager Great Lakes at Trelleborg Sealing Solutions, “we have several turbocharger seal and bearing applications in the motorsports industry. We have found that it is really important as a material supplier to work closely with customers, in this case the turbocharger manufacturers. It ensures that proper testing is conducted and achieves the desired outcome. For example, our radial oil seals have been designed to deliver longer-lasting sealing efficiency, providing high tolerance to heat while still maintaining resistance to wear and, most importantly, lowering friction. It is a matter of material science, design expertise, and advanced manufacturing techniques that are needed to achieve the kinds of results that the motorsports industry requires.”
Industry Collaboration Delivers Results
Keen collaboration between industry players and suppliers helps develop parallel or complementary materials and innovations with suppliers. Like Trelleborg, the Shell Company provides another similar example of how emerging engines can affect so many parts (seals, rings and bearings) and even other areas like fuels and the kinds of lubricants that are to be used. Alternative fuels may cause contaminants in engine oils, so scientists have set their scope to design oils with better seal compatibility.
“As new fuel efficient systems emerge, our scientists have been able to create innovative lubricants that have helped support greater fuel efficiency in a vehicle,” said Istvan Kapitany, President Shell Commercial Fuels and Lubricants Americas. “For engine oils, the lower the viscosity of the oil, the less fuel you need to power your engine. The challenge is to determine the lowest viscosity that still provides the right level of engine protection, durability and performance.”
Lighter Weight Materials take Center stage
On another front, lightweight plastics, composites and other materials are replacing heavy steel components used in exteriors and interior applications like dashboards to help improve the race car’s fuel economy footprint, which is another engineering trend making its way off the track and onto highways. The Energy Department says that reducing a car’s weight by only 10 percent can improve fuel economy by about seven percent. According to Alan Hall, a Ford technology spokesman, Ford is collaborating with Dow Automotive Systems for the purposes of achieving lower-cost carbon fiber composites for mass production. Their predictions support 750-pound weight reductions could be possible.
Since there are less regulations and price conscious considerations being made in the world of motorsports than within the automotive industry for the general public, it makes perfect sense to use cars on the track as an open test ground for pushing the limits of innovation and generating solutions that could have a far-reaching influence on the future of mobility. It truly creates the best “test bed” for all the constituents and suppliers serving the industry. It gives seal, bearing and ring providers as well as the coatings and lubricant makers a place to test out their latest concoctions in some of the most extreme vehicular conditions around.
Honda’s first sports car, the Acura NSX, uses racing technology in its engine. Titanium connecting rods, typically found in Formula One and other race engines, debuted in the exotic-appearing NSX that was introduced in 1991. This marked the first application of a specially-patented titanium alloy in the engine rods for a production car. The titanium rods each weigh 190 grams less – and are significantly stronger – compared to a steel connecting rod.
Weight reduction is a critical concern for racing and performance cars and is a key factor that is being investigated and streamlined in race cars right down to the seals and bearings. And the suppliers are listening. Trelleborg Sealing Solutions is manufacturing even lighter weight, friction reducing seals that were put to test in the Formula One and Indy car races. Torque and power consumption values do vary with the seal design and material, which is why it has become so important to use the right seal configurations to achieve the best possible performance.
Sealing the Deal: Improved Configurations
There have been some quite substantial changes. For instance, the first generation shaft seals with leather or rubber lips have given way to the use of a lighter lip to reduce torque loss. We have certainly come a long way from the old assembled designs, which functioned using sheer force and tended to have aggressive springs, wide contact bands, large interference’s and high radial loads. Today’s modern molded seals work longer and more effectively with narrow contact bands and minimal radial loads that are uniform over time.
Trelleborg’s close collaboration with race car systems and parts manufacturers proved on the track that there are still differences sprouting even between new designs. Scientists work with the seal engineers to determine the best design parameters, such as lip radial cross-section (and therefore radial load), which can result in considerable differences in torque drag. As a result, the science involved in making seals can be quite complex. Seals made for the same shaft and bore dimensions, but from various manufacturers, can have quite different power consumption characteristics. Engineers and mechanical technicians typically see the principal role of a rubber radial lip seal is to retain lubricants and exclude contamination in mechanical systems and not the most critical seal parameter, which is actually the robbed horsepower and power loss caused by the seal.
Reducing Friction and Optimizing Torque
Another important area of contention has to do with radial shaft seals, which are a lot like bearings in that these seals require an oil film to support the lip load. The performance of these seals really depends on the control of the oil film thickness under the lip, which must be controlled over a wide range of application conditions. The early hours of seal operation has proven important in order to establish a complementary directional pattern in the rubber material. The formation of this pattern is critical in making a positive pumping action by the seal lip while simultaneously smoothing the shaft. Nevertheless, seals do cause friction, which does end up consuming power. The total amount of power consumed by contacting radial lip seals can be substantial in any car system. Overall the interference between lip and shaft, the elasticity of the rubber and the spring force creates a radial load, resulting in additional torque. Something Trelleborg has been working to perfect.
“We have seen advanced polymers and elastomers gaining wider acceptance in racing circles because they boost performance and cut weight. Components made from these materials can be manufactured in complex geometries and offer high-temperature resistance and exceptional durability. It is for this reason that we’ve started to see the replacing of metals in many traditional sealing, cylinder, and housing application with racecar grade elastomer materials,” continued Gillies.
Everyone knows that a split second can make the difference between winning and losing. This is why race teams in, Formula One, IndyCar, and NASCAR are always on the lookout for parts that perform better, are more reliable, and weigh less. This also provides the right incentive for materials suppliers – who apply years of research and experience gained in demanding aerospace, semiconductor, automotive, and oil-exploration applications – to tackle the unique challenges of performance racing.
