FAILURE DETECTOR OF TURBOCHARGED ENGINE

摘要

When opening or closing an exhaust cut valve in accordance with an operation range of an engine and performing feedback control for an opening degree of a wastegate valve such that a target supercharging pressure is achieved in each of an open operation range where the exhaust cut valve is opened and a closed operation range where the exhaust cut valve is closed, a failure of the exhaust cut valve can be accurately determined. Whether or not an abnormal state occurs is determined in each range. In the abnormal state, although feedback control for closing the wastegate valve is performed, the actual supercharging pressure is lower than the target supercharging pressure, and a deviation between the actual supercharging pressure and the target supercharging pressure is maintained at not less than a predetermined value. Further, whether the exhaust cut valve is normal or in failure is determined.

主权项

1. A failure detector of a turbocharged engine,
the failure detector comprising: a turbocharger including a turbine disposed on an exhaust passage of the engine and a compressor disposed on an intake passage of the engine; an exhaust cut valve configured to be switched between an open state and a closed state to switch a flow velocity of an exhaust gas of the engine between two velocities that are high and low velocities in front of the turbine in the exhaust passage; an exhaust bypass passage through which the exhaust gas flows so as to bypass the turbine; a wastegate valve disposed on the exhaust bypass passage; a supercharging pressure detector configured to detect supercharging pressure of intake air supercharged by the compressor; and a valve control device configured to
switch the exhaust cut valve between the open state and the closed state in accordance with an operation range of the engine andperform feedback control for an opening degree of the wastegate valve such that actual supercharging pressure detected by the supercharging pressure detector becomes target supercharging pressure preset in accordance with an operation state of the engine in each of an open operation range where the exhaust cut valve becomes the open state and a closed operation range where the exhaust cut valve becomes the closed state, wherein: the valve control device is configured to
determine whether or not an abnormal state occurs in each of the closed operation range and the open operation range, the abnormal state being a state where although the feedback control in which a feedback amount for closing the wastegate valve is not less than a predetermined amount is performed, the actual supercharging pressure is lower than the target supercharging pressure, and a deviation between the actual supercharging pressure and the target supercharging pressure is maintained at not less than a predetermined value anddetermine based on results of the determinations in the above two operation ranges whether the exhaust cut valve is normal or in failure.