| 摘要 |
PURPOSE: A noise reduction method of a common rail diesel engine is provided to decrease noise by optimizing combustion noise of the common rail diesel engine on the partial load with measuring noise in the upper part of the diesel engine for removing error of data. CONSTITUTION: Noise of a common rail diesel engine is measured(110), and the noise level of frequency band having influence on the entire noise level is calculated(120). The measured and calculated noise is calculated into pressure(130), and calculated pressure is input in a proportional integral derivative controller(140). Pilot injection timing retards if the pressure is over the reference value(160). The upper limit and the lower limit of pilot injection timing are decided(170), and compared with the minimum value and the maximum value(180). The limit value is used for pilot injection timing in case of the upper limit and the lower limit to be beyond the minimum value and the maximum value(190). The pilot injection timing advances if the pressure is less than the reference value(200).
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