An Automatic Parameter Matching for Engine Fuel Injection Control

An automatic matching method for engine control parameters is described which can aid efficient development of new engine control systems. In a spark-ignition engine, fuel is fed to a cylinder in proportion to the air mass induced in the cylinder. Air flow meter characteristics and fuel injector characteristics govern fuel control. The control parameters in the electronic controller should be tuned to the physical characteristics of the air flow meter and the fuel injectors during driving. Conventional development of the engine control system requires a lot of experiments for control parameter matching. The new matching method utilizes the deviation of feedback coefficients for stoichiometric combustion. The feedback coefficient reflects errors in control parameters of the air flow meter and fuel injectors. The relationship between the feedback coefficients and control parameters has been derived to provide a way to tune control parameters to their physical characteristics. The matching method provides independent parameter matching for the injectors and the air flow meter using the matrix calculation of the feedback coefficients. Computer simulations proved the validity of the matching method where there was ±5% fluctuation in feedback coefficients. Experiments were carried out for various patterns of parameters. The experiments showed that the matching method corrected control parameters within ±5% in about a twenty minute driving period. Hence, the new matching method can improve the engine fuel controller development efficiently. It is applicable to an on-board matching algorithm for the engine controller, which offers efficient driving and low emission even if engine control parameters change.