Vehicle Lightweighting Benefits
Reducing vehicle structural weight results in even more lightweighting benefits through other systems
3M and Automotive Engineering International polled the members of the Society of Automotive Engineers in 2012 regarding how their organizations would react to meeting the increased CAFE standards. The number one technology trend identified was the need for lightweight structural materials – with 95% of respondents citing its importance. Since that time, this trend has proven out, with many automotive OEMs announcing weight savings reductions in their new models.
Vehicle Lightweighting and the Preservation of Stiffness and Structural Safety
Reducing vehicle structural weight is fundamental to higher fuel economy platforms as it does not result in any noticeable differences to the customer, as long as stiffness and safety are maintained. The reduction in structural weight also has compounded benefits resulting in associated weight reduction in other vehicle systems. If weight is taken out of the body structure less engine power is required, so the engine can be smaller and lighter. In addition, a lightweight body structure requires smaller and lighter suspension components. By having a lighter engine and smaller secondary systems, the structural weight can be further reduced, creating a positive feedback loop. Estimates for the size of this compounded weight reduction show that the savings can be doubled once mass is taken out of the other systems, with a commonly used statistic of 1kg of secondary weight reduction for every kg of primary weight savings.
How Vehicle Lightweighting Directly Impacts Fuel Economy
The result of these compounded savings in vehicle weight reduction can be significant. A 30% reduction in vehicle body-in-white (BIW) mass would represent an overall vehicle weight reduction of nearly 7%. With the add-on effects of compounded secondary weight savings, this would result in a total reduction of 13.5%. Based on an industry rule of thumb that for every 10% reduction in vehicle weight, there is an expected 7% increase in fuel economy, the compounded weight savings would then generate a 9.5% improvement in fuel economy. That is equivalent to nearly 3 MPG on a 30 MPG vehicle.