As motorcycles continue to strive for weight saving, could the future generation be made with plastic engine parts? And no, we're not joking...
Europe's largest application-oriented research organization, the Fraunhofer Project Group, believes they can reduce the weight of an engine by 20 percent using fiber-reinforced plastic parts, such as the cylinder casing and even crankcase bearings, rather than metals such aluminum. Furthermore, they believe it won't cost anymore to mass produce.
They demonstrated their experimental 650cc 'plastic' engine at the world's leading trade fair for industrial technology, the Hannover Messe, in Germany in April. Project leader Dr Lars-Fredrik Berg says they used a special fiber-reinforced phenolic composite material for the cylinder casing in the single-cylinder engine. It is made of 55 percent fibers and 45 percent resin and is cheaper than carbon fiber-reinforced composite. The material was developed by SBHPP, a business unit of Sumitomo Bakelite. The researchers have performed successful test runs on the engine and found it is not only capable of the same performance as conventional engines, but is quieter and gives off less heat. Being lighter, it would also have advantages for a motorcycle's handling, center or gravity, acceleration and fuel economy.
The biggest challenge was making the material able to withstand extreme temperatures, high pressure and vibrations without suffering damage.
'First we looked at the engine design and identified the areas subject to high thermal and mechanical loads,' Dr Berg says. 'Here we use metal inserts to strengthen their wear resistance.'
For example, the Fraunhofer researchers modified the geometry of the cylinder liner to ensure the plastic is exposed to as little heat as possible.
'The characteristics of the plastic material also play an important role,' the researchers say. 'It needs to be sufficiently hard and rigid, and resistant to oil, gasoline and glycol in the cooling water. It must also demonstrate good adherence to the metal inserts and not have a higher thermal expansion coefficient than the metal or the inserts would separate from the substrate.'
So, maybe in the near future we will see motorcycles and scooters in Thailand that are equipped with plastic engines….