FUEL INJECTION CHARACTERISTIC DETECTING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a fuel injection characteristic learning device capable of detecting an operation characteristic of a fuel injection valve on the basis of a fuel pressure in a fuel supply system with high accuracy.SOLUTION: A fuel injection characteristic detecting device is disposed with a fuel supply system having a direct injection-type fuel injection valve and a common rail, and applied to an internal combustion engine in which a fuel injection from the fuel injection valve is injected by multistage injection, and detects an actual fuel injection amount on the basis of a fluctuation mode of a fuel pressure PQ inside of the fuel supply system, detected by a fuel sensor. A fluctuation waveform of the fuel pressure PQ detected in executing main injection by the fuel sensor is formed, and the formed fluctuation waveform is corrected on the basis of a fuel temperature THQin inside of the fuel injection valve and a fuel temperature THQout of the part at a common rail side with respect to the fuel injection valve inside of the fuel supply system. An actual fuel injection amount in the main injection is detected on the basis of the corrected fluctuation waveform.