Abstract: An antechamber system Diesel engine including an antechamber consisting of a front chamber and a rear chamber and a communication port communicating said antechamber with a main combustion chamber wherein at least one of fuel injection ports of a fuel injection nozzle sprays the fuel in the direction of the communication port. The rear chamber is formed integrally with a cylinder head inside the same while the front chamber is formed on a sleeve member detachably fitted to the cylinder head. If desired, a short axis column-like cavity is defined between the front chamber and the rear chamber.

Abstract: An antechamber system Diesel engine including an antechamber consisting of a front chamber and a rear chamber and a communication port communicating said antechamber with a main combustion chamber wherein at least one of fuel injection ports of a fuel injection nozzle sprays the fuel in the direction of the communication port. The rear chamber is formed integrally with a cylinder head inside the same while the front chamber is formed on a sleeve member detachably fitted to the cylinder head. If desired, a short axis column-like groove is defined between the front chamber and the rear chamber.

Abstract: A direct injection type diesel engine including a piston having a toroidal combustion chamber wherein the ratio of the diameter of the opening of the combustion chamber to the diameter of the piston, the ratio of the diameter of the opening of the combustion chamber to the depth of the combustion chamber, the ratio of the distance between the top of a toroid of the combustion chamber and the surface of the opening of the combustion chamber to the depth of the combustion chamber and the angle of inclination of a peripheral wall of the combustion chamber with respect to the axis of the piston are each in a predetermined range of values. By these features, the problems with regard to noise and coloring of the exhaust emissions can be obviated without adversely affecting the performance of the engine.