| 摘要 |
PURPOSE:To prevent atomized fuel from adhering to the inner wall of a counter injection port and to reform fuel to reduce the amount of generated smoke, by forming the cross-section of the counter injection port in a substantially circular shape, and by setting a specific relationship between the cross-sectional area and length of the counter injection port. CONSTITUTION:Atomized fuel injected from a fuel injection valve 7 is led by a vortex stream and impinges upon a glow plug 11 so that it drops in a substantially vertical direction along the direction of the vortex stream. However due to a delay in ignition it passes through a counter injection port 10 in an atomized condition. In this arrangement, the cross-sectioned shape of the counter injection port 10 is formed to be substantially circular to facilitate the passage of atomized fuel therethrough, and the relationship between the cross-sectional area S and length L of the counter injection port is set such as, S/L>0.5 to reduce the amount of generated smoke. That is, the relationship of S/L>0.5 allows the passage length to be short with respect to the passage cross-sectional area so that fuel is directly fed into a main chamber without adhering to the inner wall 10A of the counter injection port. Therefore, fuel adhered to the inner wall 10A of the counter injection port 10 is prevented from being burnt with some delay so that the counter injection port 10 may attain its inherent purpose, and therefore, combustion may be carried out within the main chamber to reduce the amount of generated smoke. |
