摘要:
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. In a first limp home mode, the control computer is operable to drive the fuel pump as a function of fuel pressure and commanded fueling if abnormal operation of the high pressure fuel pump is detected. In this mode, the valve is controlled only as a function of fuel pressure. In a second limp home mode, the control computer is operable to drive the fuel pump with a predicted fuel pump command based on the fuel command and engine speed, if abnormal operation of the pressure sensor is detected. In this mode, the valve is controlled as a function of the fuel command and the reference pressure or a default pressure.
摘要:
A fuel system includes a pair of electronically controllable high pressure fuel pumps 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 accumulator pressure profile is processed in accordance with various techniques forming part of the present invention for diagnosing pressure sensor in-range failures, fuel pump injector valve blow shut failures and failure of one of the fuel pumps. In accordance with another aspect of the present invention, the current fuel pump command signal is compared with a predicted fuel pump command stored in said computer for diagnosing overpumping conditions. The predicted fuel pump command is preferably retrieved from a look up table as a function of engine speed, commanded fuel, and accumulator pressure.
摘要:
A fuel system includes a pair of electronically controllable high pressure fuel pumps 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 accumulator pressure profile is processed in accordance with various techniques forming part of the present invention for diagnosing pressure sensor in-range failures, fuel pump injector valve blow shut failures and failure of one of the fuel pumps. In accordance with another aspect of the present invention, the current fuel pump command signal is compared with a predicted fuel pump command stored in said computer for diagnosing overpumping conditions. The predicted fuel pump command is preferably retrieved from a look up table as a function of engine speed, commanded fuel, and accumulator pressure.