Common rail fuel injection system designed to avoid error in determining common rail fuel pressure

摘要

A common rail fuel injection system includes an electronic control unit and a fuel pressure sensor. The electronic control unit is equipped with a power supply circuit which supplies a power supply voltage to the fuel pressure sensor through a harness. The power supply voltage is used in the pressure fuel sensor as a drive voltage to drive a sensor element of the fuel pressure sensor. The electronic control unit monitors an output voltage of the fuel pressure sensor to determine the pressure of fuel in a common rail and also monitors the drive voltage applied to the fuel pressure sensor to determine whether the drive voltage is undesirably lower than the power supply voltage or not. If such a condition is encountered, the electronic control unit takes measures to avoid an excessive rise in pressure in the common rail to protect the common rail physically.