Method and device for controlling a secondary air mass flow in a secondary air supply of an internal combustion engine

Abstract

The invention relates to a method for controlling a secondary air mass flow in a secondary air supply of an internal combustion engine, wherein the internal combustion engine comprises the secondary air supply, a device for determining a pressure (ps) in the secondary air supply, and an exhaust gas lambda probe for determining a current exhaust gas lambda value (λsens), wherein the method comprises the following steps: a) Determining, using a throttle equation and depending on a pressure (ps) in the secondary air supply, a first secondary air mass flow (ṁsecAirNoAeff) related to the effective throttle area (Aeff); b) Determining a second secondary air mass flow (ṁsecAirLambda) starting from the measured exhaust gas lambda value (λsens) and taking into account a primary air mass flow (ṁair) of the internal combustion engine and a supplied fuel mass flow (ṁinj);c) Deriving an effective throttle area (Aeff) from the first secondary air mass flow rate (ṁsecAirNoAeff) determined in step a) and the second secondary air mass flow rate (ṁsecAirLambda) determined in step b); d) Controlling the secondary air mass flow rate in the secondary air supply using the effective throttle area (Aeff) determined in step c) or a quantity derived therefrom.

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