| 摘要 |
A method for controlling pulse width modulation of a variable valve timing apparatus is provided to control the position of the variable valve timing apparatus in an accurate manner by correcting the pulse width modulation control duty value of the variable valve timing apparatus if a vehicle travels at a constant speed. A method for controlling pulse width modulation of a variable valve timing apparatus includes a first step(101,103,105) of permitting an engine control unit to receive a battery signal, an engine oil temperature, a cam signal, a crank signal, a fuel pressure signal, and a coolant temperature signal, judge whether the variable valve timing apparatus satisfies a control condition, and start control of the variable valve timing apparatus if the control condition is satisfied, a second step(107,109) of calculating an engine load from engine RPM, judging whether it is a partial load from the calculated engine load, and judging whether the partial load is constant if it is a partial load, a third step(111,113) of determining a target control value of the variable valve timing apparatus if the partial load is constant, and determining a duty value based on the value obtained by modeling an actuator temperature for controlling a flow channel, and a fourth step(117,119) of calculating the difference between the target control value of the variable valve timing apparatus and the present control value of the variable valve timing apparatus, carrying out a learning process for correcting the pulse width modulation control duty value determined in the third step so as to compensate the difference between the target control value of the variable valve timing apparatus and the present control value of the variable valve timing apparatus, and correcting the pulse width modulation control duty value determined in the third step on the basis of the value of the learning of the pulse width modulation control, a preset threshold value for the pulse width modulation control, and the pulse width modulation control duty value determined in the third step.
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