MUNICH -- Will it be aluminum or steel? That has long been the question in discussing the piston material of the future.
The debate arises from the growing power density of advanced diesel engines, which increases stress on parts.
The trend eventually will force a switch from softer aluminum to steel, which can handle the higher stress. Its mechanical stability is three times greater than that of aluminum, but steel pistons are susceptible to cracking after long use.
Now that the first steel pistons for passenger cars are coming off the production line at German auto suppliers KSPG AG and Mahle GmbH, how quickly can steel pistons totally replace aluminum?