SYSTEM AND METHOD FOR ESTIMATING THE RATIO BETWEEN THE UPSTREAM PRESSURE AND THE DOWNSTREAM PRESSURE IN THE TURBINE OF A SUPERCHARGED ENGINE FOR A MOTOR VEHICLE

摘要

The invention relates to a method for estimating the ratio between the upstream pressure and the downstream pressure in the turbine of a turbocharger for a motor vehicle, including the following steps: obtaining the estimation of the mass flow of the turbine, of the rotational speed of the turbine, and of the upstream temperature of the turbine, as well as the measurement of the position of the variable-geometry turbine blades and of the downstream pressure of the turbine; determining the value of a first internal variable on the basis of physical measurements of the turbine and the initialization value of the estimator; determining the value of a second internal variable on the basis of physical measurements of the turbine, the initialization value of the estimator, and a variation in the pressure ratio; determining the derivative of the internal variables on the basis of the values of the internal variables; and obtaining the estimated value of the pressure ratio on the basis of the derivative of the internal variables.