Magnesium Powertrain Mount Brackets: New Application of Material Being used in this Sub-System for Vehicle Mass Reduction

The need for fuel economy gains is crucial in todays automotive market. There is also growing interest and knowledge of greenhouse gases and their effect on the environment. Paulstra's magnesium powertrain brackets were a solution that was presented not just to reduce the weight of the engine mounting system (which was already under its weight target before magnesium introduction), but in response of the OEM's desire to further reduce the weight of the vehicle for CAFE and weight class impact. This new engine mounting system has three powertrain mount brackets that are high-pressure die cast AZ91D magnesium alloy. This paper will show that these brackets to have a dramatic weight reduction compared to the standard aluminum die-cast material that they replaced. This paper describes the process of approval: concept and material sign-off by the OEM, FEA for strength and modal performance, corrosion, and the final product. We will show that if executed correctly, the process of replacing aluminum with magnesium for cast structural components in a mounting system is possible and should be encouraged for fuel economy gains based on weight reduction. This is the first application of magnesium in engine mounting sub-systems in North America.