US 7,254,478 B1Granted

Method of estimating airflow in an air injection reaction system

AssigneeDelphi Technologies, Inc.

InventorsAndrew D. Herman, Peter M. Olin

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Abstract

A method of estimating the quantity of secondary reaction airflow supplied to the exhaust manifold of an internal combustion engine by an air injection reaction (AIR) system models airflows in an AIR pump, an AIR valve, and a plenum coupling the pump to the valve. The pump flow is modeled based on the pump speed (or pump motor voltage), the pump inlet air temperature and the pressure ratio across the pump, and the valve flow is modeled based on the pressure ratio across the valve and the valve inlet air temperature. The plenum pressure used in the pump and valve pressure ratios is modeled based on the net plenum airflow and the plenum air temperature. The estimated AIR airflow is useful for managing the air/fuel ratio in the engine exhaust system and enhancing the reliability of AIR diagnostics.

Claims6

Dependent claims

A method of estimating an airflow delivered to an exhaust manifold of an internal combustion engine by an air injection reaction system including a driven air pump and a plenum coupling an outlet of the air pump to the exhaust manifold, the method comprising the steps of:

estimating an airflow through the pump based on an operating parameter of the pump, an inlet pressure of the pump, an inlet air temperature of the pump, and an estimate of an air pressure in said plenum;
estimating the airflow delivered to the exhaust manifold based on a pressure in the exhaust manifold, an air temperature in the plenum, and the estimate of the air pressure in said plenum;
and
updating the estimate of the air pressure in said plenum based on a difference between the estimated airflow through the pump and the estimated airflow delivered to the exhaust manifold, and the air temperature in the plenum.

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Dependencies are inferred from the claim text.