Motoring on magnesium

A magnesium car engine that weights just 14 kilograms has been retired after completing 65,000 kilometres of trouble-free motoring.

The lightweight magnesium alloy three-cylinder diesel engine block, which was installed in a Volkswagen Lupo, has spent the past three years driving around southern Germany and Austria under testing by international engine designer AVL List.

The magnesium alloy used in the engine was developed by Australian scientists working for the Cooperative Research Centre for Cast Metals Manufacturing to support a commercial development alliance between Advanced Magnesium Technologies and the German company VAW, which was then the largest independent manufacturer of sand cast aluminium engines in Europe.

Head of the research team assembled through the CRC, Dr. Colleen Bettles, from CSIRO Manufacturing and Infrastructure Technology (CMIT) says the engine could have kept going, but researchers were keen to cut the engine open to take a peek inside.

“We were keen to observe how the microstructure of the magnesium alloy may have changed over its operating life,” said Dr. Bettles. “Our initial examination has found the alloy has stood up very well.”

“Measurement of the cylinder roundness revealed a clear ovalisation in the transverse engine direction, However the distortion still remains below the acceptable limit value. Further alloy developments could reduce this significantly.”

“This testing gives us a great deal of confidence that it is possible to get significant weight reduction savings from the use of magnesium alloys,” she said.

With current cast iron engine blocks weighing around 55 kilograms, the lightweight magnesium engine is around 70 per cent lighter.

Dr. Bettles said the weight savings associated with a magnesium engine have the potential to reduce carbon dioxide emissions by 200 kilograms over a vehicle's life.

The magnesium alloy, known as AM-SC1, has been engineered to withstand long-term deformation under sustained elevated temperature, pressure and load. It has excellent strength-to-weight ratio, high shock and dent resistance, and dampens noise and vibration more than either aluminium or steel.

In another recent global technology coup, the Australian magnesium alloy has been chosen by the United States Automotive Materials Partnership (USAMP) to be the basis for its low pressure/sand cast engine research project.

USAMP is sponsored by the US Council for Automotive Research, which includes DaimlerChrysler, Ford and General Motors. Australian interests in USAMP are represented by Advanced Magnesium Technology's North American subsidiary AMT North America.