Method of reducing turbo lag in diesel engines having exhaust gas recirculation

In a compression ignition engine including a variable geometry turbocharger having a compressor and turbine, said turbine responsive to a turbocharger signal for regulating the intake manifold pressure (MAP), and an exhaust gas recirculation (EGR) passage having an EGR valve connecting an intake manifold and exhaust manifold of the engine, said EGR valve responsive to an EGR valve control signal for regulating the flow of exhaust gas and resulting mass airflow into said intake manifold (MAF), a method of reducing turbo lag comprising the steps of:

• determining a first value indicative of the engine speed;
• determining the current engine fueling rate (Wf);
• determining the requested fueling rate (Wf,REQ);
• determining a MAP value indicative of the current intake manifold pressure;
• determining a MAF value indicative of the current intake manifold mass airflow;
• and
• if Wf,REQ>Wf, then determining an intake manifold pressure and intake manifold mass airflow setpoint, MAPd and MAFd, as a function of said first value and Wf,REQ;
• generating modified setpoints, MAFc and MAPc, as a function of MAFd and MAPd, respectively;
• generating said turbocharger signal as a function of MAPc, MAP, MAFc, and MAF;
• generating said EGR valve control signal as a function of MAFc and said MAF value;
• else, generating said turbocharger signal as a function of MAPd and said MAP value;
• generating said EGR valve control signal as a function of MAFd and said MAF value;
• and
• incrementally adjusting the position of said EGR valve and said turbocharger turbine as a function of said turbocharger signal and said EGR valve control signal until said MAF value corresponds to said MAFd and said MAP value corresponds to said MAPd.

In a compression ignition engine including a variable geometry turbocharger having a compressor and turbine, said turbine responsive to a turbocharger signal for regulating the intake manifold pressure (MAP), and an exhaust gas recirculation (EGR) passage having an EGR valve connecting an intake manifold and exhaust manifold of the engine, said EGR valve responsive to an EGR valve control signal for regulating the flow of exhaust gas and resulting mass airflow into said intake manifold (MAF), a method of reducing turbo lag comprising the steps of:

• determining a first value indicative of the engine speed;
• determining the current engine fueling rate (Wf);
• determining the requested fueling rate (Wf,REQ);
• determining a MAP value indicative of the current intake manifold pressure;
• determining a MAF value indicative of the current intake manifold mass airflow;
• determining an intake manifold pressure and intake manifold mass airflow setpoint, MAPd and MAFd, as a function of said first value and Wf,REQ;
• generating said turbocharger signal as a function of MAPcS, MAP, MAFc, and MAF;
• generating said EGR valve control signal as a function of MAFc and MAF;
• and
• incrementally adjusting the position of said EGR valve and said turbocharger turbine as a function of said turbocharger signal and said EGR valve control signal until said MAF value corresponds to said MAFd and said MAP value corresponds to said MAPd.