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Control method and apparatus for turbocharged diesel engines having exhaust gas recirculation

  • US 6,128,902 A
  • Filed: 01/26/1999
  • Issued: 10/10/2000
  • Est. Priority Date: 01/26/1999
  • Status: Expired due to Fees
First Claim
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1. A method of controlling the airflow into a compression ignition engine having an exhaust gas recirculation (EGR) passage including a 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 into said intake manifold, and a variable geometry turbocharger (VGT) including a compressor connected to a turbine, the compressor in communication with the intake manifold and the turbine in communication with the exhaust manifold, said turbine responsive to a turbocharger signal for regulating the intake manifold pressure, the method comprising the steps of:

  • determining a desired intake manifold pressure (p1d) and desired EGR flow fraction (rd);

    detecting the intake manifold pressure (p1);

    generating a first deviation (ep1) between the desired and detected intake manifold pressure;

    detecting the exhaust manifold pressure (p2),estimating the EGR flow fraction (r);

    generating a second deviation (er) between the desired and estimated EGR flow fraction;

    determining an open loop EGR valve control value (Vegr) and an open loop turbocharger value (Vvgt) as a function of the current engine speed and fueling rate;

    generating proportional and integral feedback gains for the EGR valve (Kp,egr, Ki,egr) and turbocharger turbine (Kp,vgt, Ki,vgt);

    generating said EGR valve control signal (Uegr) as a function of Vegr, Kp,egr, Ki,egr and er ;

    generating said turbocharger signal (Uvgt) as a function of Vvgt, Kp,vgt, Ki,vgt and ep1 ;

    controlling the EGR valve in accordance with Uegr to regulate r; and

    controlling the turbocharger turbine in accordance with Uvgt to regulate p1.

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