Fuel pressure control device for high pressure fuel injection system

摘要

In a fuel pressure control apparatus for a high-pressure fuel injection system provided with a common rail (15), a supply pump (13) for force-feeding fuel to the common rail, and a fuel injection valve (17) attached to each cylinder of a diesel engine (1) and connected at one end to the common rail (15), an attempt is made to securely reduce a surplus of fuel pressure making use of a limited period during which normal fuel injection is not carried out. In exclusively performing pressure-release of fuel in the common rail (15) by driving the fuel injection valve (17) within an invalid injection period, the fuel injection valve (17) is driven in a cycle that does not depend on an operational condition of the engine (1), while adjusting a timing for driving the fuel injection valve (17) in such a manner as to prevent interference with the normal fuel injection control.