FUEL INJECTION CONTROL DEVICE OF DIESEL ENGINE

摘要

A fuel injection control device of a diesel engine is provided. The device includes an engine body, a fuel injection valve, a turbocharger, a low-pressure EGR system, and a controller for operating the engine body. Within a predetermined high engine-load operating range, the controller controls the fuel injection valve to operate the low-pressure EGR system and perform main and post injections. Within the operating range where the post injection is performed, when the engine load is lower than a predetermined load, an injection amount of the post injection is set to a first injection amount and an injection timing of the post injection is set to a first timing, and when the engine load is higher than the predetermined load, the injection amount of the post injection is set to a second injection amount and the injection timing of the post injection is set to a second timing.

主权项

1. A fuel injection control device of a diesel engine, comprising:
an engine body having a cylinder; a fuel injection valve for injecting a fuel into the cylinder; a turbocharger having a turbine disposed in an exhaust passage of the engine body and a compressor disposed in an intake passage of the engine body; a low-pressure EGR system for introducing exhaust gas extracted from a position of the exhaust passage downstream of the turbocharger, into a position of the intake passage upstream of the turbocharger; and a controller for operating the engine body by controlling an injection mode of the fuel through the fuel injection valve, and the circulation of the exhaust gas through the low-pressure EGR system, wherein when an operation state of the engine body is within a predetermined high engine-load operating range where turbocharging by the turbocharger is performed, the controller operates the low-pressure EGR system and controls the fuel injection valve to perform a main injection and a post injection after the main injection, and wherein within the operating range where the post injection is performed, the controller performs a post-injection switching control in which when the engine load is lower than a predetermined load, an injection amount of the post injection is set to a first injection amount and an injection timing of the post injection is set to a first timing, and when the engine load is higher than the predetermined load, the injection amount of the post injection is set to a second injection amount that is less than the first injection amount, and the injection timing of the post injection is set to a second timing that is advanced than the first timing.