Abstract: A fuel system includes an electronically controllable high pressure fuel pump operable to supply high pressure fuel from a lower pressure fuel source to a high pressure fuel collection chamber having a pressure sensor associated therewith. The fuel collection chamber feeds an electronically controllable valve operable to dispense the high pressure fuel to a fuel distribution unit supplying fuel to a number of fuel injectors. A control computer is provided for controlling the high pressure fuel pump and valve in response to requested fueling, engine speed and fuel pressure provided by the pressure sensor. The control computer is normally operable to drive the fuel pump as a function of fuel pressure and a reference pressure, which is based on requested fueling, and to control the valve as a function of commanded fueling, which is a function of engine speed and a reference speed based on requested fueling, and fuel pressure.

Abstract: A system for controlling fuel flow in an internal combustion engine receives a command specifying a desired fuel flow rate from an electronic control module. The system generates a feedforward estimate of actuator current required to produce the desired flow rate. This estimate is combined with a fueling current offset value generated using a proportional-integral feedback controller. A differential pressure between the fuel rail and cylinder gas is converted, by surface interpolation based on a lookup table, to an estimate of actual fuel flow rate. The difference between this actual fuel flow rate and the desired flow rate is provided to the feedback controller as an error signal. The feedback controller preferably uses different gain values depending on an operating mode of the engine (speed control and torque control modes).