| 摘要 |
PURPOSE: To reduce black smoke, and restrain generation of nitrogen oxides by forming a circular recessed part in the center of a piston top surface, and forming a guide groove to communicate a sub-corabustion chamber and the circular recessed part with each other so that fuel gas blown out of the sub-combustion chamber is turned in the same direction with an instake air turning flow in the circular arc recessed part. CONSTITUTION: In an intake stroke of an engine, an instake valve 16 is opened, and an instake air turning flow shown by R1 is formed in a main combustion chamber 15. Next, in a compression stroke, the turning flow remains in the main combustion chamber 15, and in the upper dead center, since a recessed part 30 becomes all of the main combustion chamber volume, the intake air turning flow remains only in the recessed part 30. In the compression stroke, a part of intake air is introduced to a sub combustion chamber 20, and combustive ignition is caused simultaneously with fuel injection into the sub-combustion chamber 20, and its combustion gas is derived into the main combustion chamber 15 from a nozzle port 21 so as to flamingly spread together with unburnt gas. This derived gas is mainly introduced to the recessed part 30 from a guide groove 31, and is turned by a remaining turning flow in the recessed part 30, and combustion making the best use of the intake air turning flow is realized.
|
