AIR/FUEL RATIO IMBALANCE DETECTION DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

An in-cylinder pressure sensor is attached to each of multiple cylinders. A combustion parameter (an amount of generated heat, for example) is calculated from the output of each in-cylinder pressure sensor. An amount of fuel injection is reduced such that the combustion parameter coincides with a predetermined value, thereby making the air/fuel ratio of the cylinder a lean air/fuel ratio. With regard to each cylinder, on the basis of an amount of reduction in the amount of fuel injection when control of reduction in the amount of fuel injection is performed such that the combustion parameter coincides with the predetermined value, an air/fuel ratio of each cylinder is calculated. The calculated air/fuel ratios are compared to detect an air/fuel ratio imbalance between the cylinders.