SECONDARY AIR SUPPLY APPARATUS FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide a secondary air supply apparatus for an internal combustion engine which can accurately estimate a secondary air flow rate.SOLUTION: The secondary air supply apparatus includes: an electric air pump that supplies a secondary air to an upstream side than an exhaust gas purification catalyst arranged in an exhaust passage; a control valve that opens/closes a secondary air supply passage; and a pressure detector that measures a pressure between the electric air pump and the control valve. The secondary air supply apparatus detects a first pressure in a first operating state where the control valve is closed, and a second pressure in a second operating state where the control valve is open. The secondary air supply apparatus corrects at least one of the first and second pressures based on a first driving voltage for the electric air pump in the first operating state and a second driving voltage for the electric air pump in the second operating state, and estimates a secondary air flow rate based on the pressures after the correction.