Engine Ch 1 page 14 General Apart from fuel lines and a fuel tank, a PDE (Pumpe-Dьse-Einheit) fuel system with unit injectors consists of the following items: • a feed pump • a hand pump • a fuel filter • one fuel rail. • a pressure relief valve • One PDE type unit injector per cylinder. The fuel system also includes an electronic control system. The control system includes an electronic control unit, the unit injector solenoid valves and sensors. PDE FUEL Diesel fuel oil The composition of the diesel fuel oil has a great influence on the functioning and the service life of the engine and the injection system. The engine output and exhaust emissions are also dependent on the fuel quality.
The diesel fuel must meet European standard EN 590. The table below shows the requirements for some of the most important properties: Environmentally favourable fuels (low sulphur fuels) There are three classes of so called environmentally favourable fuels (SS15 54 35). Class 1 is sulphur-free and class 2 is low in sulphur. Compared with class 3 (normal fuel), these fuels are less dense and this reduces engine power output. SHOP MANUAL MT41 - 12.2004 Property Requirement Viscosity at 40°C 2.0 - 4.5 mm2/s (cSt) Density at 15°C 0.82 - 0.86 kg/dm3 Sulphur (concentration by mass) max. 0.3% Ignitability (CET rating) min. 49 Flashpoint 56°C