Patent ID: 8991172
Filing Date: 2015-03-31
Classification: F02B,F02D,Y02T

Abstract:
1. An air-fuel ratio control device of a premix combustion engine, the device comprising: a hybrid turbocharger comprising a turbocharger having a compressor and a turbine, and a motor generator coupled with the compressor via a rotating shaft; the premix combustion engine in which air is supplied from the compressor, and from which exhaust gas is discharged toward the turbine, a generator coupled with the premix combustion engine via a rotating shaft, a charging air measuring unit coupled to the premix combustion engine for measuring an airflow rate of the air supplied to the premix combustion engine from the compressor, and a control unit for controlling the motor generator based on operating conditions of the generator or the premix combustion engine, the control unit comprising a CPU configured to calculate an airflow rate required for the operation of the premix combustion engine with an air-fuel ratio based on a power output of the generator; and calculate a power output or a rotation speed of the hybrid turbocharger so that a difference between the calculated airflow rate and the measured airflow rate approaches zero; and an exhaust gas bypass unit having a bypass passage, a flow rate regulating valve provided on the bypass passage so as to adjust the output of the turbine, and a switch configured to transmit a control order regarding an opening level of the flow rate regulating valve to the flow rate regulating valve, the control order determined based on the difference between the calculated airflow rate and the measured airflow rate so that the difference approaches zero, wherein: the CPU is configured to judge whether or not the power output of the hybrid turbocharger exceeds a prescribed maximum level, and the CPU is configured to turn on the switch so as to transmit the control order to the flow rate regulating valve and control the opening and closing of the flow rate regulating valve when the power output of the hybrid turbocharger exceeds the prescribed maximum level.