Fuel injection device of direct injection engine

摘要

A fuel injection device of a direct injection engine is provided. The device includes an engine body, a fuel injection valve, and a controller for controlling a fuel injection by the fuel injection valve. The fuel injection valve has a nozzle hole, a valve body for opening and closing the nozzle hole, and first and solenoid coils for stroking the valve body by first and second stroke amounts, respectively. The controller performs the fuel injection by the first solenoid coil in an intake stroke period within an engine operating range with an engine load below a predetermined load. The controller performs the fuel injection with a fuel pressure of 40 MPa or above by the second solenoid coil in a period between a compression stroke late stage and an expansion stroke early stage within a low-engine-speed range with an engine speed below a predetermined speed within a high-engine-load range.

主权项

1. A fuel injection device of a direct injection engine, comprising:
an engine body; a fuel injection valve for directly injecting fuel containing gasoline into a cylinder of the engine body; and a controller for controlling the fuel injection by the fuel injection valve, the fuel injection valve including:
a nozzle hole for opening to face inside the cylinder;a valve body for stroking to open and close the nozzle hole;a first solenoid coil for stroking the valve body by a first stroke amount; anda second solenoid coil for stroking the valve body by a second stroke amount, wherein the controller operates the first solenoid coil and not the second solenoid coil to stroke the valve a first lift amount and thereby perform the fuel injection at least in an intake stroke period, when an operating state of the engine is within a range where an engine load is at least below a predetermined load within a low-engine-load range where compression-ignition combustion is performed, and wherein the controller operates at least the second solenoid coil to stroke the valve body a second lift amount that is greater than the first lift amount and thereby perform the fuel injection with a fuel pressure of 40 MPa or above in a period between a late stage of compression stroke and an early stage of expansion stroke, only when the operating state of the engine is within a low-engine-speed range where an engine speed is below a predetermined speed within a high-engine-load range where the engine load is higher than the low-engine-load range.