Fuel pressure control apparatus and method of internal combustion engine

摘要

The amount of fuel ejected from a high-pressure fuel pump (47) that ejects fuel toward a delivery pipe (53) is adjusted by controlling the valve closure start timing of an electromagnetic spill valve (54). In this manner, the fuel pressure in the delivery pipe (53) is controlled. The duty ratio DT used for controlling the valve closure start timing of the electromagnetic spill valve (54) is calculated based on a valve closure start timing that provides a maximum amount of fuel ejection. The actual fuel ejection characteristic of a high-pressure fuel pump (47) may deviate from a designed state due to individual differences of the pump. However, the valve closure start timing of the electromagnetic spill valve (54) that provides the maximum amount of fuel ejection in accordance with the actual fuel ejection characteristic is learned as a maximum ejection timing. Based on the maximum ejection timing, the duty ratio DT is calculated. <IMAGE>