| 摘要 |
PURPOSE:To reduce the generation of smokes and nitrogen oxides and improve the idle noise by forming a communication hole having a specific sectional area for allowing a spiral-flow chamber and a main combustion chamber to communicate, onto a hot plug. CONSTITUTION:A communication hole 4 for allowing a spral-flow chamber 1 and a main combustion chamber 3 to communicate is formed on a hot plug 2. As for said communication hole 4, the area B of the superposed part between the both opened surfaces Q1 and Q2 is made 5% or less with respect to the projected opened area Q of the communication hole 4 when the opened surface Q1 on the spiral-flow chamber side and the opened surface Q2 on the main combustion chamber side are projected, viewed from the main combustion chamber side. The sectional area A of the communication hole 4 is made 1.2% or more with respect to the area of a piston 5. Thus, generation of smokes and nitrogen oxides can be suppress, and idle noise is improved, and fuel consumption can be improved. |
