| 摘要 |
PURPOSE:To reduce the noise of a Diesel engine, by prescribing the relationship among the cross-sectional area and equivalent length of a communication passage and the capacity of a swirl chamber. CONSTITUTION:In a Diesel engine with a swirl chamber 3 and a communication passage 5 for connecting the swirl chamber and a main combustion chamber 6 to each other, the relationship among the cross-sectional area S and equivalent length l of the communication passage 5 and the capacity V of the swirl chamber 3 is set as S/lV<0.057. As a result, the resonance frequency of a resonator consisting of the swirl chamber 3 and the communication passage 5 is made 3,000Hz or more both when the temperature of vaporized fuel is low and when the temperature is high. The resonance frequency is thus shifted out of a region of 2kHz in which the noise level of the Diesel engine is highest. For that reason, the noise level of the Diesel engine is prevented from rising due to the multiplication of the noise level by the resonance frequency. |
