Method for determining the total pressure in the cylinder of an engine

A method for determining a total pressure in a cylinder (Pcyl) of an engine as a function of an angular position (crk) of a crankshaft (14) and from a quantity of fuel to be injected in possibly several injections, and for controlling a quantity of fuel injected into the engine, the method comprising:

• determining the pressure in the cylinder when there is no combustion, said pressure being called the pressure without combustion (Pcyl_m),
• determining, for each injection (inji), a curve of sub-variation of pressure (ΔPcomb_i) caused by a combustion of the fuel quantity injected during the injection (inji) in question, a shape of the curve being estimated as a function of the quantity of fuel (MFi) to be injected and of an angular position for start of injection (SOIi) of the corresponding injection,
• determining the total pressure in the cylinder (Pcyl) by adding together the pressure without combustion (Pcyl_m) and the pressures given by the pressure sub-variation curves (ΔPcomb_i) of each injection (inji),
• adjusting an injector opening duration based on the total pressure of the cylinder.