Patent ID: 9404436
Filing Date: 2016-08-02
CPC Classification: F02D

Claim Text:
1. A method for operating an internal combustion engine, the internal combustion engine comprising an engine block defining a cylinder accommodating a reciprocating piston coupled to rotate a crankshaft, a fuel injector for injecting fuel inside the cylinder, and a crank position sensor positioned proximal to the crankshaft, the method comprising the steps of: commanding the fuel injector to perform a test fuel injection with a predetermined energizing time; using the crank position sensor to determine a crankshaft acceleration signal during the test fuel injection; filtering the crankshaft acceleration signal and obtaining a filtered crankshaft acceleration signal; determining a value of an amplitude of a fundamental frequency component of the filtered crankshaft acceleration signal and obtaining a determined value of the amplitude of the fundamental frequency component; determining a correction factor of the predetermined energizing time on a basis of a difference between the determined value of the amplitude of the fundamental frequency component and a preset value thereof; and using the correction factor to correct an energizing time of subsequent fuel injections performed by the fuel injector, wherein the filtering of the crankshaft acceleration signal comprises the steps of: wherein the parameter proportional to the amplitude of the noise is calculated by filtering the crankshaft acceleration signal with each of the plurality of notch filters in order to obtain an output crankshaft acceleration filtered signal (F_out(i)) for each of the plurality of notch filters, each output crankshaft acceleration filtered signal (F_out(i)) being compared to an average value of the crankshaft acceleration signal (CS_Avg) in order to calculate a deviation (F_out(i)−CS_Avg) from the average value of each output crankshaft acceleration filtered signal, and by integrating the deviation from the average value (F_out(i)−CS_Avg) of each output crankshaft acceleration filtered signal to calculate an integral value (F_int(i)) proportional to the amplitude of the noise for each output crankshaft acceleration filtered signal.