Patent Document ID: 6122589
Application ID: 09289532
Patent Flag: 1

Claim One:
1. A fuel injection control system of an engine which is operable by a signal of fuel injection quantity on an intake side of the engine, and the performance of which is indicatable by a signal of the air-fuel ratio on an exhaust side of the engine, said control system comprising: an intake air quantity estimation unit for estimating the quantity of intake air, which is programmed to output an estimated intake air quantity signal based on predetermined input signals of engine conditions; an intake fuel quantity estimation unit for estimating the quantity of intake fuel, which is programmed to output an estimated intake fuel quantity signal based on predetermined input signals of engine conditions; an estimated air-fuel ratio calculation unit for calculating an estimated air-fuel ratio, which is programmed to output an estimated air-fuel ratio signal when receiving the estimated intake air quantity signal and the estimated intake fuel quantity signal; a target air-fuel ratio setting unit for setting a target air-fuel ratio, which is programmed to output a target air-fuel ratio signal based on predetermined input signals of engine conditions; and a feedback control unit for providing a fuel injection signal to the engine, which is programmed to provide a fuel injection signal for controlling fuel injection when receiving and comparing the estimated air-fuel ratio signal and the target air-fuel ratio signal, said fuel injection signal being outputted also to the intake fuel quantity estimation unit as one of the predetermined input signals; wherein at least one unit selected from the intake air quantity estimation unit, the intake fuel estimation unit, and the target air-fuel ratio setting unit is provided with a learning function, said learning function being programmed to modify output from the at least one unit based on teacher data, wherein the teacher data used in the intake air quantity estimation unit and the intake fuel quantity estimation unit are a deviation of the actual air-fuel ratio from the estimated air-fuel ratio under given engine conditions, and the teacher data used in the target air-fuel ratio setting unit are a factor correlated to the actual air-fuel ratio under given engine conditions.