The road to improved vehicle fuel economy runs through the rubber industry, and it won't be an easy path for automotive component makers.
Major design and material formulation changes for manufacturers of rubber vehicle engine parts will result from the Obama administration's stringent fuel economy goals for the U.S. vehicle fleet, according to industry executives. Big players like Freudenberg-NOK say they are on the case, working closely with their customers to provide effective, long-lasting parts for the next generation of vehicle engines.
However, engines running on ethanol and methanol present very different challenges from electric vehicle motors and hybrid engines.
The first engine type represents reformulation of seals, belts and other parts already common to internal combustion engines, whereas the second entails in many cases a total rethinking of parts design.
Ethanol and methanol
Plymouth, Mich.-based Freudenberg is conducting ongoing research into the powertrain requirements created by ethanol and methanol, according to the company.
Freudenberg is documenting the effects of methanol and other alternative fuels on traditional gasoline engine components, said Joseph Walker, Freudenberg corporate director, material development, and David Sakata, Freudenberg vice president, technology and product warranty.
Widely variable fuel blends in different parts of the world require new, robust designs and materials for polymeric engine components, according to Walker and Sakata. Especially in China, they said, fuel blends can vary widely from region to region.
“Most gasoline for sale today contains 10-percent alcohol anyway,” Walker said. “What has happened with biofuels is that it's forced everyone to consider what concentration of alcohol they have in their fuel. If you use conventional gas one time and gas with 15-percent ethanol the next, what is the total alcohol content in your fuel?”
Freudenberg—a major supplier of seals, O-rings and engineered shapes for vehicle engines—has had to evaluate standard materials for their performance in ever greater levels of ethanol and methanol, according to Walker and Sakata.
Much of the research has been performed at Freudenberg's operations in Brazil, where high levels of biofuels in gasoline have been common for many years.
“We've found that certain concentrations are more deleterious to certain materials than other blends,” Walker said. “E15 (15-percent ethanol) is not so bad, but E22 (22-percent ethanol) is an aggressive, corrosive fuel.
“Remember that this hasn't affected just auto engines, but outboard motors, lawn mowers and the like.”
Many industries and associations are lobbying against the U.S. Environmental Protection Agency decision to allow E15, according to Sakata. In the auto aftermarket, many fear the corrosiveness of E15 on traditional parts, particularly those made for vintage and hobbyist cars, he said.
Whatever the case, this research drove Freudenberg to develop material formulations and designs for seals that could operate effectively with biofuels, according to Walker and Sakata. Research into China's biofuels became especially important because China uses far more methanol in vehicle fuel than the U.S.
The China factor
“China is using coal gasification in much the same way that we are using corn,” Walker said. “China also has an unregulated ability to vary formulations on the provincial level. Depending on the concentration of methanol, different materials react differently with methanol than with ethanol.”
To quantify the effect of Chinese meth¼anol on powertrain automotive seals, Walker is leading an 18-month study examining various polymer architectures and ingredient influences on the longevity of rubber components in contact with methanol.
Walker said he hopes to complete the study in time for the Society of Automotive Engineers conference in Detroit in February.
“Most of our work is for a global platform,” Sakata said. “We are trying to find materials compatible with fuels in different regions of the world.”
As well as compatibility with biofuels, Freudenberg is mindful of federal fuel economy edicts, Walker and Sakata said.
Early last year, Freudenberg launched the Energy Saving Seal, designed to use less than one-fourth of the energy used by conventional radial shaft seals.
If ESS technology was used in the engine, transmission, axle and bearing seals of all light vehicles, the U.S. would save more than 2 billion gallons of gasoline annually, Freudenberg said in introducing ESS.
Gates Corp. faced somewhat different challenges with ethanol and methanol than Freudenberg because Gates' power transmission belts and belt drive systems don't come into direct contact with the fuel, said Kyoyul Oh, vice president of technology for the Gates Power Transmission Division, and Graeme Knox, technical director for North America for the division.
Both Oh and Knox are based at Gates' facility in Rochester Hills, Mich.
Nevertheless, biofuels brought real challenges, they said. Belts didn't need to be redesigned from traditional gasoline engines, but they did require different materials.
“Because of the difference in engine dynamics, we may need to change from an A-modulus belt with polyester cord to a higher modulus with cord made of aramid,” Oh said. “We have to manage the higher angular vibration in the engine.”
Electric and hybrid engines
Electric and hybrid vehicles offer altogether different challenges to rubber engine parts manufacturers than ethanol and methanol, experts agree.
“Electric 'engines' are actually electric motors,” said Lyle Shuey, vice president of marketing for Rochester Hills, Mich.-based Bright Automotive Inc.
There is very little overlap in the design features of electric motor and internal combustion engines, Shuey said, although electric drives may require a cooling system similar to gasoline engines.
A pure electric motor requires all sorts of rubber parts not found in gasoline engines, such as motor mounts, wiring harnesses, isolation materials, and mounting components for the battery, power inverters and other electronics.
Hybrid engines, Shuey said, still call for virtually all the rubber parts of a gasoline engine, though some future hybrids may use fuel cells as their backup power source.
Freudenberg intends to be just as much a factor in electric motor parts supply as in parts for internal combustion engines, according to Walker and Sakata.
“If you replace an internal combustion engine with an electric or hybrid engine, there will be changes,” Walker said. “Valve cover seals and head gaskets will go away. But as long as there are moving parts, there must be seals.”
Electric motors require totally new types of seals, such as seals that circulate liquid coolant, Walker and Sakata said.
Hybrid vehicles present a particular opportunity for Gates, because several major hybrid systems are belt-driven, significantly increasing the power demands on belts, according to Oh and Knox.
“To address that need, we have to increase the capability of the belt,” Knox said.
Electric motors may mean an end to alternators, compressors and other parts, but they don't necessarily mean an end to belts, according to Oh.
A great deal of engineering R&D is being done to maximize both the storage and efficient use of energy in electric vehicles, and belts are likely to play a role in that, he said.
In 10 years' time, Gates expects to participate in the electric vehicles market at a much greater level, according to Oh.
“We will always need to utilize energy in the best possible way to carry passengers from Point A to Point B,” he said. “Our mix of products will change, but I expect our business to grow.”