Patent ID: 7487632

Claim:
A method of injecting secondary air into an exhaust of an automotive vehicle with a catalytic converter, such method comprising: providing an air injection system, the air injection system having: a source of pressurized air; a conduit for carrying pressurized air from the source to an exhaust pipe from the vehicle; and a variable flow rate valve in the conduit for controlling the rate of airflow through the conduit; injecting pressurized air from the conduit of the air injection system through the variable flow rate valve into the exhaust pipe at a location upstream of the catalytic converter; collecting air injection system pressure data; collecting air injection system pulsation data; calculating at least one air injection flow value from the air pressure data as a function of engine airflow data; determining if there is a unique air injection flow value calculated from the air pressure data as a function of engine flow data; calculating a unique air injection flow value from the system pulsation data as a function of engine airflow data if there is not a unique air injection flow value calculated from the air pressure data as a function of engine flow data; reporting the unique air injection flow value; and controlling the rate of airflow through the variable flow rate valve into the exhaust pipe as a function of the unique air injection flow value.