Rail pressure control system and method for electronic control voltage-accumulation distribution common rail system of diesel engine

The invention relates to a Rail pressure control system and method for an electronic control pressure-accumulation distribution common rail system of a diesel engine. The system comprises a flow valve and an electronic control unit, wherein the electronic control unit is connected with a sensor module which comprises a crankshaft position sensor, an accelerator pedal sensor, a rail pressure sensor, a barometric pressure sensor and a cooling liquid temperature sensor. According to the system and the method, in the starting period of the diesel engine, the electronic control unit carries out closed-loop control on the opening degree of the flow valve to enable the rail pressure in the common rail system of the diesel engine to fast reach a preset rail pressure value so as to guarantee the smooth starting process of the diesel engine; and when the rail pressure reaches the preset rail pressure value, the electronic control unit detects the rail pressure value by the rail pressure sensor according to the opening