Passenger cars have typically been equipped with aluminum pistons for the sole reason that they’re lighter than their steel counterparts. Although aluminum can slash the weight of an auto’s engine the metal’s biggest drawback is its high rate of thermal conductivity. Because of that attribute higher combustion chamber temperatures can’t be reached and aluminum piston engines run with decidedly less efficiency.
While steel pistons have been widely used in commercial and heavy vehicles for decades, Mercedes is forging a new path by offering steel pistons for passenger cars.
According to Mercedes’ engineers the new steel pistons will debut in the 2015 V6 E 350 BlueTEC sedan. Aside from generating the same amount of power (258HP) as its aluminum piston antecedent, the steel pistons will also improve the luxury vehicle’s fuel efficiency by roughly 3 percent. What’s more, each of Mercedes’ steel pistons will be smaller than its aluminum counterpart and sport a more exacting tolerance, reducing the gap between the piston and its cylinder housing and reducing untreated emissions.
Image Courtesy of Daimler