As an electronic control system with its inherent degrees of freedom, common rail for medium-speed diesel engines offers engine developers a considerably wider spectrum of injection curve design; total combustion will prevent harmful constituents from being produced in the exhaust gas.

The MAN Diesel common rail system is designed for the use of heavy fuel oil with viscosities of up to 700 cSt at 50 degrees Celsius. These fuels have to be preheated to a temperature of up to 150 degrees Celsius in order to reach a suitable injection viscosity. Another problem with heavy fuel in electronic controlled injection systems is the high content of abrasive particles and aggressive components in these fuels.