http://www.automotiveproductsfinder.com/Articles/AR2005/NOV/Steelpistons.asp
The Monotherm piston is made of a single forged piece, which means that, unlike the Ferrotherm piston, the piston skirt is formed as one part together with the pin bosses and piston crown. This results in significant advantages: Connecting the skirt to the pin bosses leads to a larger available bearing area to accept the highest peak cylinder pressures. The piston pin no longer needs to hold the piston skirt, so it can be
shorter and lighter. Extremely compact dimensions are possible. For example, a compression height of only 50 per cent of the cylinder diameter can be achieved. The thermally stable steel skirt reduces friction; reduced fitting clearances lead to a better guidance of the piston. The guiding quality of the piston, especially in the ring area, results in better levels of oil consumption and blow-by. In addition, the Monotherm piston includes high rigidity and long life. This type of piston combines a maximum mechanical loading capacity of up to 250 bar with other important criteria such as lower fuel and oil consumption, lower noise level and less weight. While the first engine with Monotherm pistons already went into volume production in North America in construction equipment in 2000, the weight-optimised design has replaced an aluminium
piston without any increase in the oscillating masses of the piston and pin.
