M-System

The MAN M-System, also referred to as M-Process and M combustion process, is a direct injection system for Diesel engines.

In M-System engines, the fuel is injected onto the walls of the combustion chamber that is solely located inside the piston, and shaped like a sphere.

In combination with the relatively low injection pressure, this results in a fine fuel film on the combustion chamber walls.

[2] The idea of this operating principle is creating an air-fuel mixture that is more homogeneous with a dispersion of air and fuel that is more even than in regular Diesel engines.

[2] M-System engines suffer from high heat-transfer and flow losses, resulting in reduced efficiency and therefore higher fuel consumption.

FM is an abbreviation for the German word Fremdzündungsmittenkugelverfahren, meaning spark ignition centre sphere combustion process.

[4] After World War II, J. Siegfried Meurer, then an MAN engineer, continued development of the M-System and prepared it for series production.