Control system for internal combustion engines

Abstract

A control system for an internal combustion engine according to one aspect of the invention calculates a total amount of evaporative fuel purged from a canister based on dynamic characteristics and concentration of purged gas. The system calculates an amount of evaporative fuel supplied to the combustion chamber of the engine based on the total amount of evaporative fuel and depending on dynamic characteristics of the purged gas. Then, the system determines a required amount of fuel to be injected by a fuel injection valve based on the amount of evaporative fuel supplied to the combustion chamber. A control system according to another aspect of the invention calculates an amount of fuel to be injected by the injection valve and the ratio of the amount of fuel to be injected to the amount of fuel to be purged from the canister based on operating conditions of the engine, and based on this ratio, controls the purge control valve and at the same time decreases the amount of fuel to be injected, while setting a limit to this ratio for maintaining the linear relationship of the valve opening period of the fuel injection valve and the fuel injection amount.