Analysis of Aluminum and Steel Pistons—Comparison of Friction, Piston Temperature, and Combustion

While steel pistons have been in use for a long time in commercial vehicle diesel engines, the first series production applications for passenger car diesel engines are currently imminent. The main reason for the use of steel pistons in high speed diesel engines is not, as maybe initially hypothesized, the increasing requirements on the component strength due to increasing mechanical loads, but rather challenges based on the actual CO₂-legislation. The increasing requirements to reduce the fuel consumption necessitate new innovative technologies. The imminent penalties for exceeding the prescribed CO₂ emissions seem to make the steel piston a viable alternative today, despite its higher manufacturing costs. So far, the CO₂-benefits using steel pistons were mainly ascribed to the reduced friction between piston and cylinder liner due to no thermal interference.