As pressures in gasoline engine combustion engines get higher as vehicle manufacturers work toward delivering reduced CO2 emissions and improved fuel economy, it’s necessary to redesign and reengineer components, particularly as these engines are downsized. According to powertrain engineers at Federal-Mogul (federalmogul.com), within the next few years specific power outputs from engines will increase from around 95 kW/liter to 130 kW/liter, and peak combustion pressures from 110 bar to 130 bar—higher, up to 160 bar, for engines running fuels like E100 or compressed natural gas.
To address this, the company has developed a new piston architecture, which it calls the “Advanced Elastoval II.”
While one might think that in order to withstand increased pressures there would be thicker walls and consequently a heavier piston, this piston actually has wall sections as thin as 2.5 mm compared with previous sections of 4 mm. What’s more, it is up to 20% lighter.
Said Arnd Baberg, chief engineer, product engineering, Federal-Mogul Powertrain Energy, “Any reduction in wall thickness requires the entire piston structure to be redesigned.”
The new piston has complex curved side panel forms that are inclined in two planes and closer together to support the piston crown. There are multiple weight-reducing pockets and crown reinforcing ribs. There are different skirt widths for the thrust and non-thrust sides of the piston, which helps contribute to the light weight, as well.
It is scheduled to go into series production in late 2012.
The 2016 model is all-new. As in platform and everything else. And the platform—which will have global use—was developed in North America.
Generally, when OEMs produce aluminum engine blocks (aluminum rather than cast iron because cast iron weighs like cast iron), they insert sleeves into the piston bores—cast iron sleeves.
A young(ish) guy that I’ve known for a number of years, a man who spent the better part of his career writing for auto buff books and who is a car racer on the side, mentioned to me that his wife has a used Lexus ES Hybrid.