Patent ID: 7637097

Claim:
A control method for an internal combustion engine provided with a secondary air supply apparatus that supplies secondary air to a portion upstream of an exhaust gas control device in an exhaust system, the method comprising: a step of detecting failure in the secondary air supply apparatus; and a step of limiting an amount of air introduced into a cylinder via an intake manifold of the internal combustion engine to a predetermined amount when failure in the secondary air supply apparatus is detected in the step of detecting failure, wherein the internal combustion engine includes plural cylinders; and the secondary air supply apparatus includes i) a first opening/closing valve which opens/closes a first air passage through which air discharged from an air pump flows; ii) a second opening/closing valve which opens/closes a second air passage one end of which is connected to the first air passage at a portion downstream of the first opening/closing valve, and the other end of which is connected to an exhaust passage leading to a predetermined cylinder among the plural cylinders; and iii) a third opening/closing valve which opens/closes a third air passage one end of which is connected to the first air passage at a portion downstream of the first opening/closing valve, and the other end of which is connected to an exhaust passage leading to a cylinder different from the predetermined cylinder to which the exhaust passage connected to the second air passage leads, and wherein in the step of detecting failure a detector detects presence or absence of failure in each of the first opening/closing valve, the second opening/closing valve, and the third opening/closing valve; and the controller limits the amount of the air introduced into the internal combustion engine according to presence or absence of failure in each of the first opening/closing valve, the second opening/closing valve, and the third opening/closing valve.