American Car Fair Materials
1986/10/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria
Plastics are known to melt and break ceramic. However, two engines of these materials have been presented at a recent Automobile Fair in the U.S. city of Detroit.
The plastic motor is designed to run in the famous Indianapolis race and is a 2.6 liter turbo engine. This engine, made between the Amoco Chemicals Corp. and Polimotor Research Inc. industries, contains parts made from a plastic called Torlon. Some of them are segments, piston rods and valve stems. The motor block and cylinder head are made of carbon fibre reinforced plastic.
Although these plastics are very good, they cannot withstand the heat of the cooking chamber. It therefore has cast cylinders, steel valves and aluminium piston heads.
Second, Kyocera Corp. We have a ceramic engine manufactured by the Japanese company. These have built a four-cylinder diesel turbomotor. The pistons and cylinders are made of ceramic. Because the ceramics easily withstand high temperatures, Japanese designers have not had to design a cooling system for the engine.
On the other hand, the Japanese house Nissan, the first commercial car with ceramic turbo, is about to settle in the street. The rotor of this turbo is made of silicon nitride (Si3N4) instead of nickel alloy. As the rotor is lighter, its moment of inertia has decreased by 35%. This results in a more flexible response and thus a huge increase in acceleration.
The rotor is first extruded, inserted into the furnace and finally analyzed with X-rays to detect possible defects.