Patent attributes
A method of controlling exhaust gas recirculation (EGR) in a turbocharged compression-ignition engine system including an engine, an induction subsystem in upstream communication with the engine, an exhaust subsystem in downstream communication with the engine, a high pressure EGR path between the exhaust and induction subsystems upstream of a turbocharger turbine and downstream of a turbocharger compressor, and a low pressure EGR path between the exhaust and induction subsystems downstream of the turbocharger turbine and upstream of the turbocharger compressor. A target total EGR fraction for compliance with exhaust emissions criteria is determined, then a target HP/LP EGR ratio is determined to optimize other engine system criteria within the constraints of the determined target total EGR fraction.
