Patent ID: 7171960
Filing Date: 2007-02-06
Classification: F02D,F02M

Abstract:
1. A control apparatus for an internal combustion engine comprising: a canister that temporarily adsorbs and stores evaporated fuel generated in a fuel supply system including a fuel tank; a purge control valve that is arranged in a purge passage connecting between said canister and an intake system of an internal combustion engine for controlling the flow rate of purge air comprising a mixture of said evaporated fuel and air when said purge air is introduced into said intake system; an injector that is arranged in the neighborhood of an intake port or in a combustion chamber of said internal combustion engine for supplying fuel to said internal combustion engine; an operating condition detection section that detects an operating condition of said internal combustion engine; an air fuel ratio sensor that is arranged in an exhaust system of said internal combustion engine for detecting an air fuel ratio in an exhaust gas; a target purge rate calculation section that calculates, as a target purge rate, a target value of a purge rate that is a ratio between an amount of intake air of said internal combustion engine and said purge flow rate, based on said engine operating condition; a target purge flow rate calculation section that calculates a target purge flow rate based on said engine operating condition and said target purge rate; a purge flow rate control section that controls said purge control valve so that said purge flow rate becomes said target purge flow rate; an air fuel ratio feedback control section that controls an amount of fuel supplied from said injector in a feedback manner so that said air fuel ratio becomes a target air fuel ratio; a purge air transport delay calculation section that calculates a combustion chamber purge flow rate based on a transport delay that occurs until the purge air supplied to said intake system through said purge control valve reaches said combustion chamber, and also calculates an air fuel ratio sensor neighborhood purge flow rate based on a transport delay that occurs until said purge air exerts an influence on the value of said air fuel ratio detected by said air fuel ratio sensor; an intake air transport delay calculation section that calculates a combustion chamber intake air amount based on a transport delay that occurs until intake air detected by said operating condition detection section reaches the interior of said combustion chamber, and also calculates an air fuel ratio sensor neighborhood intake air amount based on a transport delay that occurs until said intake air exerts an influence on the value of said air fuel ratio detected by said air fuel ratio sensor; a fuel transport delay calculation section that calculates an air fuel ratio sensor neighborhood fuel amount based on a transport delay that occurs until the fuel supplied by said injector exerts an influence on the value of said air fuel ratio detected by said air fuel ratio sensor; a combustion chamber purge rate calculation section that calculates a combustion chamber purge rate based on said combustion chamber purge flow rate and said combustion chamber intake air amount; an air fuel ratio sensor neighborhood purge rate calculation section that calculates an air fuel ratio sensor neighborhood purge rate based on said air fuel ratio sensor neighborhood purge flow rate and said air fuel ratio sensor neighborhood intake air amount; a purge air concentration calculation section that calculates a purge air concentration based on said air fuel ratio sensor neighborhood purge rate, said air fuel ratio sensor neighborhood intake air amount, said air fuel ratio sensor neighborhood fuel amount, and the air fuel ratio detected by said air fuel ratio sensor; a purge air concentration learning value calculation section that calculates a purge air concentration learning value by applying averaging processing or filtering processing to said purge air concentration; and a fuel amount correction section that corrects the amount of fuel to be supplied to said internal combustion engine based on said combustion chamber purge rate and said purge air concentration learning value.