Vibration Control ContiTech tested the new resource named Taraxagum for anti-vibration technology at the end of 2015 by manufacturing its first dandelion rubber engine mount.
The work is linked to a joint project between parent group Continental AG and Fraunhofer Institute for Molecular Biology and Applied Ecology, which have been studying the production of natural rubber from Russia dandelion for the manufacture of tires.
“When it comes to natural rubber we have completely different requirements from our colleagues in the tire division,” said Dr Anna Misiun, who leads the project to build engine mounts made from dandelion rubber at ContiTech.
An engine mount, she explained, connects the engine to the car body, so it has to withstand considerable static loads. It also provides insulation against structure-borne engine noise and restricts engine movement so vehicle occupants are not shaken about inside the car.
The components are therefore exposed to high dynamic loads and high temperatures, so the natural rubber used needs to meet demanding specifications.
ContiTech’s test results, said Misiun, showed that Taraxagum was a suitable alternative to traditional natural rubber and ideal for vibration control elements on engines.
But the dandelion products will not hit the market for at least five to ten years.
“One of the biggest challenges will be obtaining the material on an industrial scale,” said Misuin, adding that the research team is working to optimise the seeds and develop suitable cultivation and harvesting technology.
PU to the rescue
Another interesting advance, from Japanese Sumitomo Riko Group, is the development of magnetic induction foaming (MIF), a process that increases the thermal conductivity of polyurethane foams to address the problem of noise in electric vehicles.
According to the Anvis group, which represents Sumitomo Riko in Germany, MIF makes it possible to increase the thermal conductivity in such a way that the heat can be diverted to the exterior while providing acoustic insulation and reducing weight in non-stop operations.
“This process works with both internal-combustion engines and electric motors,” said Olaf Hahn, managing director of the Anvis Group.
“Electric drive systems and actuators will produce perceptible noises, which could affect comfort,” Hahn explained.
Current PU materials are only partially suited for dampening engine noise because they lack the properties needed to facilitate thermal conductivity, according to Hahn.
The basis for MIF, he added, is a new process that alters material properties by forming thermal bridges.
“The result is a sound-proofing, heat-conducting material,” he explained.
The product was put to the test in the real world with the help of an electric motor cover.
“During a two-hour endurance test, the temperature levels of the MIF-altered engine cover were 20˚C lower than those of a cover made with conventional polyurethanes,” the Anvis Group managing director reported.
The noise-reduction effect, however, varied by frequency.
According to Hahn, the sound proof effect has the most impact with frequency more than 400 hertz.