Engine with precombustion chambers

An engine with precombustion chambers, having a cylinder head fixed to a cylinder block provided with cylinders, suction and exhaust valves adapted to open and close suction and exhaust ports formed in said cylinder head, main combustion chambers formed in said cylinders, pistons comprising piston heads in which precombustion chambers are provided and piston skirts fixed to said piston heads, and adapted to be moved reciprocatingly in said cylinders, communication ports communicating said main combustion chambers and said precombustion chambers with each other, and fuel injection nozzles fixed to said cylinder head and capable of injecting fuel into said precombustion chambers, wherein:

• said main combustion chambers are formed by cavities provided in said cylinder head,
• said precombustion chambers being formed in the substantially central portions of said piston heads,
• said communication ports comprising main communication ports formed in the substantially central portions of said piston heads and communicating said main combustion chambers and said precombustion chambers with each other, and auxiliary communication ports formed around said main communication ports so as to extend incliningly toward the circumferences of said cylinders and communicating said main combustion chambers and said precombustion chambers with each other,
• said fuel injection nozzles having heat insulating structures, and being adapted to project into said main communication ports in positions in the vicinity of the top dead centers of said pistons and close the same and provided with injection ports for injecting a fuel into said precombustion chambers, and said auxiliary communication ports being formed in an offset manner with respect to the centers of said precombustion chambers, turning flows of flames injected from said precombustion chambers into said cavities through said auxiliary communication ports being mixed with suction swirls existing in said main combustion chambers.

An engine with precombustion chambers, having a cylinder head fixed to a cylinder block provided with cylinders, suction and exhaust valves adapted to open and close suction and exhaust ports formed in said cylinder head, main combustion chambers formed in said cylinders, pistons comprising piston heads in which precombustion chambers are provided and piston skirts fixed to said piston heads, and adapted to be moved reciprocatingly in said cylinders, communication ports communicating said main combustion chambers and said precombustion chambers with each other, and fuel injection nozzles fixed to said cylinder head and capable of injecting fuel into said precombustion chambers, wherein:

• said main combustion chambers are formed by cavities provided in said cylinder head,
• said precombustion chambers being formed in the substantially central portions of said piston heads,
• said communication ports comprising main communication ports formed in the substantially central portions of said piston heads and communicating said main combustion chambers and said precombustion chambers with each other, and auxiliary communication ports formed around said main communication ports so as to extend incliningly toward the circumferences of said cylinders and communicating said main combustion chambers and said precombustion chambers with each other,
• said fuel injection nozzles having heat insulating structures, and being adapted to project into said main communication ports in positions in the vicinity of the top dead centers of said pistons and close the same and provided with injection ports for injecting a fuel into said precombustion chambers, wherein said cavities are provided with escape recesses for flames which are enlarged toward the circumferences of turning flows of flames injected from said precombustion chambers into said main combustion chambers through said auxiliary communication ports.