Functional description

With active pressure regulation, the DDE activates the rail pressure regulating valve with various pulse duty factors. In doing so, the DDE regulates the rail pressure to the calculated target pressure. The fuel that is taken off is fed by the rail-pressure regulating valve into the return line. Depending on the type of activation, the pressure control valve allows more or less fuel to flow from the high pressure side into the virtually depressurized return line. The more fuel flows into the return flow the lower the pressure build-up on the high-pressure side.

Fig 1: Identifying Rail Pressure Regulating Valve And Plug Connection

Courtesy of BMW OF NORTH AMERICA, INC.