Patent ID: 9726091
Date: 2017-08-08
CPC Classifications: F02D,F02M,Y02T

Claim:
1. A method, comprising: operating an internal combustion engine including an intake system with a compressor and an exhaust system with a turbine, a high pressure exhaust gas recirculation (EGR) loop connecting the exhaust system upstream of the turbine to the intake system downstream of the compressor, and a low pressure EGR loop connecting the exhaust system downstream of the turbine to the intake system upstream of the compressor; recirculating exhaust gas to the intake system through both the high pressure EGR loop and the low pressure EGR loop to combine with an intake air flow and provide a charge flow to an intake manifold of the internal combustion engine that includes an EGR fraction indicative of a ratio of the recirculated exhaust gas to the charge flow; determining a desired oxygen concentration in the charge flow to the internal combustion engine; determining a NOx concentration in the charge flow; determining an engine out NOx concentration in the exhaust gas; and adjusting the EGR fraction in response to the NOx concentration in the charge flow and in the exhaust gas to adjust an actual oxygen concentration in the charge flow toward the desired oxygen concentration.