The invention discloses a
rail pressure control method for a
gasoline direct injection engine
common rail fuel
system, which includes: the first step, building a
mathematical model of the
gasoline direct injection engine
common rail fuel
system, namely building a
mathematical model of a high-pressure pump, then building a
common rail mathematical model and finally building a mathematical model of a fuel
injector; the second step, simplifying the mathematical model of the common rail fuel
system; the third step, designing the
control algorithm and regulating the form of the
control algorithm on the basis of the mathematical model of the common rail fuel system; the fourth step, filtering by a
rail pressure sensor and delaying
signal transmission, namely acquiring
rail pressure signals by an AD (analog-digital) passage of a single-
chip microcomputer and removing individual error points and
signal interference by the
filter algorithm, and then designing
signal tests for the rail
pressure sensor (7); the fifth step, testing characteristics of a
pressure control valve, converting the output of the
control algorithm into action time of the
pressure control valve, namely testing the characteristics of the
pressure control valve (5) to acquire relation between the switching
delay of the pressure control valve (5) and
voltage of a vehicular storage battery and then building the relation between the opening angle of the pressure control valve (5) and the flow of the high-pressure pump (3).