Abstract
Generalized algorithms of the air-fuel ratio control by using the estimated air mass in the cylinder were presented to obtain highly accurate control during transient conditions in high supercharged direct injection systems with a complex air induction system. The air mass change was estimated by using physical models which estimated the pressure of the intake manifold by introducing the output of the air flow meter and the differential of the output into aerodynamic equations of the intake system. The air mass into the cylinders was estimated at the beginning of the intake stroke under a wide range of driving conditions, without compensating for changes in engine conditions. Therefore, the algorithms required relatively minor calibration changes for each engine modification can estimate the air mass on a cylinder by cylinder basis. The fuel mass could be injected without delay during the intake stroke, keeping the air-fuel ratio within 1% of the target value during transient conditions.