Patent ID: 7925420
Filing Date: 2011-04-12
Classification: F02D

Abstract:
1. A method for determining and putting in a quantity of fuel on the basis of a value of the target of the air-fuel ratio in an internal combustion engine equipped with a plurality of cylinders and injectors having a Control Unit and a device for each cylinder including a coil, a spark plug, a polarisation circuit, and an acquisition circuit; the method comprising: measuring, in each cylinder of said engine, the ion current of the combustion of the air-fuel mixture (IC), from the beginning of the spark occurring in said spark plug through to the end of the ion phenomenon; registering the values of said ion current IC during each chemical and thermal phase of the combustion of the air-fuel mixture in each cylinder of said engine; calculating the value of the integral of the registered values of said ion current IC during each chemical and thermal phase of the combustion of the air-fuel mixture (ΣI) in each cylinder of said engine; registering the value of said integral ΣI; determining the value of the temporal length of each chemical and thermal phase of said ion current IC during the combustion of the air-fuel mixture (T) in each cylinder of said engine; registering said value T; determining the average value of said ion current IC in each chemical and thermal phase of the combustion of the air-fuel mixture in each cylinder of said engine on the basis of the ratio of the registered value of said integral ΣI and of the registered value of said temporal length T (VM); registering said average value VM; registering the value of each maximum peak of said ion current IC during the chemical phase of the combustion of the air-fuel mixture (P); determining the value of the time interval between the spark occurring in said spark plug and each maximum peak of said ion current IC during the chemical phase of the combustion of the air-fuel mixture (Tp); registering said time interval value Tp; determining the value of speed of the flame front of said engine on the basis of the ratio between said value P and the value of said time interval Tp (FFS); registering the value of said speed of the flame front FFS; determining a value (L registering said value L determining a value (L registering said value L determining the value of the air-fuel ratio in each cylinder of said engine (Cylinder lambda) on the basis of the value of the weighted average between said value L registering said Cylinder Lambda value; determining the value of the target of the air-fuel ratio (Correction Value) comparing said Cylinder lambda value with a predetermined value of the air-fuel ratio (Reference lambda); and registering said Correction Value; to put in a quantity of fuel into each cylinder of said engine on the basis of said Correction Value.