RAIL PRESSURE CONTROL DEVICE FOR COMMON RAIL TYPE DIESEL ENGINE

摘要

PROBLEM TO BE SOLVED: To provide a rail pressure control device for a common rail type diesel engine reducing electric power consumption of a pressure reducing valve for preventing abnormal rise of rail pressure and keeping deterioration of fuel economy caused by the same at the minimum.

SOLUTION: In normal time when rail pressure Prail does not abnormally rises, valve opening pressure Pset of the pressure reducing valve for system protection is controlled to normal set pressure Pnml at high pressure side by offset quantity Pofst from target rail pressure tgtPrail and electric power consumption of the pressure reducing valve is reduced, and the valve opening pressure Pset of the pressure reducing valve is increased to upper limit set pressure Plmtl and the pressure reducing valve is opened when rail pressure Prail reaches the upper limit set pressure Plmtl if abnormal rise of the rail pressure is determined.

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