MAHLE says it is developing a new generation of piston coatings that are intended to guide and reduce the heat entering the pistons. The company claims this initially reduces the demand for piston cooling, and the increased exhaust gas temperature allows a higher quantity of energy to be extracted by waste heat recovery (WHR) systems. At the same time, the higher exhaust gas temperature permits faster heating of the exhaust gas after-treatment system following the cold start. The resulting decrease in NOx emissions makes it easier to comply with current and future legislation.
The company also claims it has optimised the piston galleries – for example on its MonoLite piston with its kidney-shaped cross section. It’s claimed this allows a temperature reduction of up to 20 kelvin without any negative impact on the aging process of the oil used.