초록 ▼

A diagnostic system for a fuel system of an internal combustion engine such as direct-injection gasoline engine monitors a pressure deviation of a actual fuel pressure sensed by a fuel pressure sensor from a desired fuel pressure in a feedback fuel pressure control, and thereby detects abnormality i

A diagnostic system for a fuel system of an internal combustion engine such as direct-injection gasoline engine monitors a pressure deviation of a actual fuel pressure sensed by a fuel pressure sensor from a desired fuel pressure in a feedback fuel pressure control, and thereby detects abnormality in the fuel system. When the pressure deviation continues to be outside a normal range, a diagnostic controller commands engine operation in a homogeneous stoichiometric combustion mode, and monitors a feedback correction quantity in a feedback stoichiometric air fuel control during the engine operation in the homogeneous stoichiometric combustion mode. The controller attributes the abnormality to the fuel pressure sensor if the feedback correction quantity of the air fuel ratio is fixed to an upper limit or a lower limit.

대표청구항 ▼

[ What is claimed is:] [1.] A diagnostic control method for detecting malfunction in a fuel system for a fuel injection type internal combustion engine, the method comprising;a pressure sensing step of sensing an actual fuel pressure with a fuel pressure sensor;a pressure controlling step of perform

[ What is claimed is:] [1.] A diagnostic control method for detecting malfunction in a fuel system for a fuel injection type internal combustion engine, the method comprising;a pressure sensing step of sensing an actual fuel pressure with a fuel pressure sensor;a pressure controlling step of performing a feedback fuel pressure control to reduce a pressure deviation of the actual fuel pressure sensed by the fuel pressure sensor from a desired fuel pressure;an abnormality detecting step of detecting abnormality in the fuel system by monitoring the actual fuel pressure;a richer combustion mode effecting step of effecting a feedback air fuel ratio control in a predetermined richer combustion mode if the abnormality is detected; anda diagnosing step of judging whether to attribute the abnormality to the fuel pressure sensor, by monitoring performance of the feedback air fuel control in the richer combustion mode.