FUEL PRESSURE CONTROL DEVICE

摘要

PURPOSE: To control fuel pressure securely unrelated to elasped change of discharge efficiency of a fuel pump or instrumental error caused from machine error of the fuel pump and capacity error of a fuel piping system. CONSTITUTION: Fuel stored in a fuel tank 251 is pressed by a booster pump 25 and fuel pump 53 and stored in a common rail and directly injected in a cylinder by fuel injection valves 211-214 disposed for every cylinder. Fuel pressure is detected by a pressure sensor 231 and compared with target pressure and to determine control amount in a control part 26, learning value is changed when the control amount excesses determined range and elapsed variation or machine error of the fuel pump and capacity error of a fuel piping system are absorbed to maintain pressure characteristic by correcting the control amount by learning value and determining operation amount of a fuel pressure control part 254.