Patent ID: 8286610

Claim:
An internal combustion engine control device, comprising: an air-fuel ratio sensor that detects air-fuel ratio of an exhaust gas of an internal combustion engine; a stoichiometric air-fuel ratio calculation device that calculates a stoichiometric air-fuel ratio based on the air-fuel ratio detected value detected by the air-fuel ratio sensor; an air-fuel ratio-based lower calorific value ratio calculation device configured to calculate a lower calorific value ratio of a fuel from the stoichiometric air-fuel ratio calculated by the stoichiometric air-fuel ratio calculation device, based on a known relationship between the lower calorific value ratio and the stoichiometric air-fuel ratio; and an O 2 sensor that detects oxygen concentration in the exhaust gas of the internal combustion engine, wherein the air-fuel ratio-based lower calorific value ratio calculation device calculates the lower calorific value ratio based on a weighted average stoichiometric air-fuel ratio calculated by weighting the air-fuel ratio detected by the air-fuel ratio sensor with an output value of the O 2 sensor, and wherein the lower calorific value ratio herein is a proportion of the lower calorific value ratio of a present fuel to the lower calorific value of a standard gasoline fuel.