Development of Lightweight Oil Pans Made of a Heat-Resistant Magnesium Alloy for Hybrid Engines

A new heat-resistant magnesium alloy (hereafter referred to as “ACM522”) for die-casting based on the Mg-Al-Ca-RE system has been developed by Honda R&D Co.

In the 150°C temperature range, the ACM522 alloy yields high creep resistant characteristics which are superior to the conventional AE42 heat-resistant magnesium alloy, and it also exhibits an excellent resistance to both heat and corrosion which can be favorably compared with the A384 general-purpose aluminum alloy. The use of magnesium for oil pans has raised a number of issues such as reduced axial force in the bolted areas and, until now, oil pans made of magnesium had not reached the stage of commercial viability for mass-produced automobiles. The authors applied the ACM522 alloy to develop light-weight oil pans which are 35% lighter than conventional aluminum oil pans. Further, these lightweight magnesium oil pans have been adopted in the engines of Honda's hybrid cars which, for mass-produced gasoline-powered cars, achieve the world's best fuel consumption of 35 kilometers per liter, and their mass production commenced from November 1999.