Piston Design
Auto-Thermal pistons have cast-in steel struts between the skirt and pin bosses. When the piston heats up, these struts have the effect of limiting the expansion of the piston in the direction of the thrust axis. Transverse slots at the same time prevent passing of heat. Potential weakness and less combustion press endurance is the obvious defect for this type of pistons.
This kind of piston also has cast-in steel struts, but without transverse slots in the ring groove. It combines extremely smooth running with a high degree of strength for high-output engines.
The top and sometimes lower compression ring grooves are machined into Ni Resist Bonded insert. This insert counteracts the high degree of wear occurring in the top groove, This type is applied to Diesel engines, particularly those with turbo charging.
Special head shape (combustion chamber) especially for diesel engines.
Pistons with cooling channel are used whenever high operating temperature occurs. This intensive oil cooling counteracts the high temperatures in the piston crown and ring belt.
