Method for correcting the reduced mass flow rate of a compressor in an internal combustion engine turbocharged with a turbocharger

A method for correcting an estimated reduced mass flow rate of a compressor in an internal combustion engine turbocharged with a turbocharger including a turbine and a compressor;

• the internal combustion engine having an intake manifold, a number of cylinders, and an exhaust system having an exhaust manifold wherein each cylinder is connected to the intake manifold by at least one respective inlet valve and to the exhaust manifold by at least one respective exhaust valve, to allow direct passage of a portion of air from the intake manifold to the exhaust manifold which does not participate in combustion so as to reduce turbolag;
• the method comprising the steps of:
• determining a control law providing a target position of a wastegate as a function of a measured actual supercharging pressure and of the estimated reduced mass flow rate (MR) of the compressor;
• correcting the estimated reduced mass flow rate (MR) of the compressor as a function of enthalpy of a gas mixture flowing through the turbine of the turbocharger and comprising both exhaust gases leaving the cylinders and the air passing directly from the intake manifold to the exhaust manifold;
• determining the target supercharging pressure;
• determining a first open-loop contribution factor of a corrected target position of the wastegate with the control law and as a function of the target supercharging pressure;
• determining a second closed-loop contribution factor of the corrected target position of the wastegate with the control law and as a function of the actual supercharging pressure;
• calculating the corrected target position of the wastegate by adding the first open-loop contribution factor and the second closed-loop contribution factor;
• and
• controlling the wastegate so as to pursue the corrected target position of the wastegate.