Patent ID: 11898509
Assignee: NISSAN MOTOR CO., LTD.
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F  Y | IPC F

Claim 7:
8. An exhaust gas recirculation (EGR) estimation device for estimating an EGR rate in an intake and exhaust system, the intake and exhaust system comprising:
an intake passage that is connected to the internal combustion engine,
an exhaust passage that is connected to the internal combustion engine,
an EGR valve in which a gap occurs even when the EGR valve is fully closed, due to a structure of the EGR valve, and
an EGR passage comprising an upstream EGR passage that connects the exhaust passage to the EGR valve, and a downstream EGR passage that connects the EGR valve to the intake passage,
the EGR estimation device comprising:
a determination control unit configured to, when a fuel cut of the internal combustion engine is started the EGR valve fully closed:
maintain the EGR valve fully closed during the execution of a fuel cut of the internal combustion engine, and
during the execution of the fuel cut of internal combustion engine and/or after fuel injection of the internal combustion engine is restarted, determine a gas replacement state by exhaust gas and fresh air in the upstream EGR passage; and

an estimation control unit configured to estimate the EGR rate based on a result of the determination of the gas replacement state.