It's a common engineering practice: find ways to improve performance without sacrificing efficiency. In the automotive world, it means more horsepower and better fuel economy. Fiat-Chrysler Automobiles has a solution in a new aluminum alloy that can better withstand heat as the boost is cranked up and compression ratio rises in turbocharged engines.
It's called ACMZ, and it uses copper as a strengthening component. Most aluminum alloy mixes feature silicon, which offers heat protection in cylinder heads up to 392 degrees Fahrenheit. With ACMZ, a cylinder head can withstand temperatures up to 572 degrees Fahrenheit. The new material comes from a $3.5 million project the federal government sponsored. Other automakers also tackled the issue of aluminum alloy at high temperatures, but their solutions did not include copper. Thus, FCA and its partner, Oak Ridge National Laboratory, earned a competitive edge in the process.
ACMZ also lets engineers narrow the "bridge" area in the cylinder head (the area between valves, spark plug, and direct fuel injector). Thus, more space makes room for larger valves, a second spark plug, and more flexibility to find the balance of power and efficiency needed in the particular vehicle application.
Oak Ridge employed its Titan supercomputer to help create 50 proposed aluminum alloy-copper recipes and then simulate their cooling and performance abilities. The technology meant FCA never had to physically create the aluminum alloy to test it. Instead, the supercomputer eliminated trial and error while engineers better understood the recipes at an atomic level.
Although FCA and Oak Ridge created the new material, it will eventually be available for other companies to use via the government partnership. FCA said it will still be a few years before ACMZ enters production for cylinder heads, but it's already begun running production and testing the material in cylinder heads based on today's engines. Aside from the material's numerous other benefits, castings made with ACMZ do not require any special equipment and can be made with tools available today.
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