New common rail systems suited for diesel engines from 1 to 5 Megawatt: modeling simulations and hardware results

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New common rail systems suited for diesel engines from 1 to 5 Megawatt: modeling simulations and hardware results

Ganser, Marco / Moser, Ulrich / Hauger, Lars

The compressibility of the fuel and the effects of pressure wave dynamics govern the injection in a Common Rail System (CRS). The layout of the system volume and its geometrical distribution within the system therefore strongly affect the injection events at every injector. Based on the simulation results achieved when modeling the CRS by means of the hydraulics simulation tool AMESim, new common rail injectors and high pressure pumps were designed, built and tested. They represent the key to novel systems which are best suited for Diesel Engines with an overall power output from 1 to 5 MW, as used in locomotives, ships, power generation and heavy earthmoving machinery. The injectors have an accumulator chamber within an injector body which easily fits into the engine's cylinder head. The actuating components are all placed in the front part, leading to a compact design. The injection rates of the injector demonstrate its good performance with or without multiple injections. The injection law is compared to that of a former system equipped with rails without an accumulator in the injector. A high pressure pump with a sinusoidal eccentric shaft and a sliding shoe between the shaft and the base of each plunger delivers the pressurized fuel. To obtain a long operating life, special emphasis has been given to the lubrication between the plunger base and the shoe. The pressure in the working chamber of each plunger is transmitted to its base by means of a small piston. The new pump for the above mentioned Common Rail Systems is of very simple design. The performance results demonstrate its excellent hydraulic efficiency.