Patent attributes
An electrically driven type low-pressure fuel pump whose flow rate can be set draws fuel from a fuel tank and discharges it at a prescribed pressure commonly to a low-pressure fuel supply system including intake manifold injectors and a low-pressure delivery pipe and to a high-pressure fuel supply system including in-cylinder injectors, a high-pressure delivery pipe and a high-pressure fuel pump. The discharge flow rate of the low-pressure fuel pump is set based on required supply quantities to the low-pressure fuel supply system and to the high-pressure fuel supply system obtained according to the engine operation conditions. The discharge quantity of the fuel pump in the internal combustion engine can be set as appropriate, and thus, deterioration in fuel efficiency due to excessive flow rate setting and operation failure due to insufficient fuel supply can be prevented, whereby reliability is improved.
