System for controlling turbocharger compressor surge

System for controlling turbocharger compressor surge, comprising:

• an internal combustion engine having intake and exhaust manifolds;
• a turbocharger including a compressor having an inlet fluidly coupled to ambient and an outlet fluidly coupled to said intake manifold;
• an exhaust gas recirculation (EGR) valve disposed in-line with an EGR conduit fluidly coupled between said intake and exhaust manifolds, said EGR valve responsive to an EGR valve control signal to control exhaust gas flow therethrough;
• means for determining a mass flow parameter corresponding to a mass flow rate of fresh air supplied to said intake manifold;
• a speed sensor producing a speed signal indicative of turbocharger speed;
• and
• a control computer configured to determine a mass flow rate surge value, corresponding to a fresh air mass flow rate above which turbocharger compressor surge is avoided, as a function of said speed signal, said control computer limiting said EGR valve control signal as a function of said mass flow parameter and said mass flow rate surge value to maintain exhaust gas flow through said EGR valve at a flow rate below which said turbocharger compressor surge is avoided.