| 摘要 |
PURPOSE: A heater drive control method of an oxygen sensor is provided to enable utilization even when low exhaust temperature is maintained by exactly forecasting the dew point passing time of the oxygen sensor without the use of hardware and controlling the heating strength of the oxygen sensor. CONSTITUTION: A heater drive control method of an oxygen sensor comprises steps of deciding whether an engine is in a starting state(S10); setting up the heater drive duty of the oxygen sensor to zero percent, setting up a dew point passing flag to False, and setting up a restart routine flag to False(S20); calculating the heat capacity transmitted to the oxygen sensor(S30); calculating the restart frequency(S40); calculating the dew point passing heat capacity(S50); deciding dew point passing by comparing the heat capacity transmitted to the oxygen sensor with the dew point passing heat capacity(S60); driving a heater by controlling the heater drive duty of the oxygen sensor to 100 percent(S70); driving the heater by restricting the heater drive duty of the oxygen sensor to a predetermined restriction value(S80); deciding whether the engine is throttled or an ignition key is turned off(S90); and storing a related variable value to a non-volatile memory of an engine control unit(S100).
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