Controlling exhaust gas recirculation in a turbocharged engine system

A computer usable medium embodying instructions executable by a processor to enable a method of controlling exhaust gas recirculation (EGR) in a turbocharged engine system including a high pressure (RP) EGR path and a low pressure (LP) EGR path, the method comprising:

• determining a target total EGR fraction for compliance with exhaust emissions criteria;
• and
• using a control subsystem having one or more controllers in communication with one or more sensors constructed and arranged to determine a target HP/LP EGR ratio to optimize other engine system criteria within the constraints of the determined target total EGR fraction, and including:
• using at least engine speed and load as an input to a base model to output a base EGR value;
• using at least one other engine system parameter as an input to at least one adjustment model to output at least one EGR adjustment value;
• adjusting the base EGR value with the at least one EGR adjustment value to generate an adjusted EGR value;
• and
• using the adjusted EGR value to construe controllable engine components to optimize other engine system criteria while ensuring that emissions criteria are met.

A product including apparatus for implementing a method of controlling exhaust gas recirculation (EGR) in a turbocharged engine system including a high pressure (HP) EGR path and a low pressure (LP) EGR path, the method comprising:

• determining a target total EGR fraction for compliance with exhaust emissions criteria;
• and
• using a control subsystem having one or more controllers in communication with one or more sensors constructed and arranged to determine a target HP/LP EGR ratio to optimize other engine system criteria within the constraints of the determined target total EGR fraction, and including:
• using at least engine speed and load as an input to a base model to output a base EGR value;
• using at least one other engine system parameter as an input to at least one adjustment model to output at least one EGR adjustment value;
• and
• adjusting the base EGR value with the at least one EGR adjustment value to generate an adjusted EGR value;
• and
• using the adjusted EGR value to construe controllable engine components to optimize other engine system criteria while ensuring that emissions criteria are met.

An exhaust gas recirculation apparatus for an internal combustion engine for use in carrying out a method of controlling exhaust gas recirculation (EGR) in a turbocharged engine system including a high pressure (HP) EGR path and a low pressure (LP) EGR path, the method comprising:

• determining a target total EGR fraction for compliance with exhaust emissions criteria;
• and
• using a control subsystem having one or more controllers in communication with one or more sensors constructed and arranged to determine a target HP/LP EGR ratio to optimize other engine system criteria within constraints of the determined target total EGR fraction, and including:
• using at least engine speed and load as an input to a base model to output a base EGR value;
• using at least one of fuel economy, engine system performance, engine system protection, or engine system maintenance as an input to at least one adjustment model to output at least one EGR adjustment value;
• adjusting the base EGR value with the at least one EGR adjustment value to generate an adjusted EGR value;
• and
• using the adjusted EGR value to construe controllable engine components to optimize other engine system criteria while ensuring that emissions criteria are met;
• and
• changing amounts of EGR gas flowing through at least one of a low pressure EGR passage or a high pressure EGR passage to increase temperature of an exhaust subsystem device,
• comprising:
• a control subsystem having one or more controllers in communication with one or more sensors constructed and arranged to determine a target HP/LP EGR ratio to optimize other engine system criteria within constraints of the determined target total EGR fraction
• a turbocharger provided with a turbine in an exhaust passage and a compressor and an intake passage;
• a low pressure EGR passage which connects the exhaust passage downstream of the turbine with the intake passage upstream of the compressor;
• a high pressure EGR passage which connects the exhaust passage upstream of the turbine with the intake passage downstream of the compressor;
• an intake manifold which connects the intake passage to the engine and an exhaust manifold which connects the exhaust passage to the engine;
• an induction subsystem device in the intake passage and an exhaust subsystem device in the exhaust passage;
• and
• at least one EGR valve changes amounts of EGR gas flowing through at least one of the low pressure EGR passage or the high pressure EGR passage such that at least one of the induction subsystem device or the exhaust subsystem device temperature is controlled.