Patent ID: 8571818

Claim:
A method for estimating a flow rate of cool air entering an engine, turbocharged by a turbocharger, including an intake manifold of volume V coll , an exchanger, an air filter, an HP EGR circuit, an LP EGR circuit, an intake butterfly valve, an exhaust butterfly valve, a flow meter, a pressure sensor, a temperature sensor connected to an electronic control unit, and a duct of volume V cool between the flow meter and the inlet of the intake manifold, the method comprising: measuring a temperature T ape after the exchanger by the temperature sensor, a pressure in the manifold P coll by the pressure sensor, and a flow rate of cool air Q flowmeter by the flow meter; computing, by the ECU, an engine flow rate Q mot based on the measurement of the temperature T ape after the exchanger and of the pressure P coll in the intake manifold; computing, by the ECU, a mass of gas between the flow meter and the inlet of the intake manifold based on the measurement of the temperature T ape after the exchanger and of the pressure P coll in the manifold; computing, by the ECU, a mass of gas in the manifold based on the measurement of the temperature T ape after the exchanger and of the pressure P coll in the manifold; measuring or estimating the HP EGR flow rate; computing, by the ECU, a gas flow rate in the manifold based on the engine flow rate and on the mass of gas in the manifold; estimating, by the ECU, a rate of LP EGR at the inlet of the manifold based on the mass of gas between the flow meter and the manifold inlet and on the flow rate of gas in the manifold; computing, by the ECU, a mass of air between the flow meter and the manifold inlet based on the LP EGR rate at the inlet of the manifold and on the flow rate of cool air Q flowmeter measured by the flow meter; estimating, by the ECU, an EGR rate {circumflex over (τ)} EGR — mot at the engine inlet based on the mass of air between the flow meter and the inlet of the manifold, on the mass in the manifold and on the flow rate of cool air Q flowmeter measured by the flow meter, estimating, by the ECU, a dynamic engine air flow rate based on the engine flow rate and on the EGR rate at the engine inlet by expression {circumflex over (Q)} air — mot =(1−{circumflex over (τ)} EGR — mot )Q mot .