Abstract: A turbocharger including an exhaust turbine and a compressor is controlled using a variable geometry apparatus at the inlet of the exhaust turbine and an exhaust bypass valve bypassing the exhaust turbine. Operating conditions of the engine driven by the turbocharger are detected as is the supercharging pressure produced by the compressor. A deviation between the detected supercharging pressure and a target supercharging pressure is calculated and integrated. A controlled variable is calculated for actuating at least one of the variable geometry apparatus and the exhaust bypass valve based on the operating conditions and a learned value. Feedback control is used to correct the controlled variable in accordance with the integrated value of the deviation. A determination is made as to an operating range in which feedback control is to be performed and the learning amount is calculated in accordance with the result of the operating range determination and the integrated value of the deviation.

Abstract: A method and apparatus is disclosed for controlling the supercharging pressure in a turbocharger to obtain sufficient turbocharging even in low speed operating ranges. The supercharging pressure is regulated by a variable geometry means and an exhaust bypass valve means, which in turn are responsive to control means which receive feedback correction. The feedback correction is based on calculated controlled variables. Optimum control of the supercharging pressure is accomplished by finding a learning amount based on the feedback correction which in turn is used to modify the calculated control variables.