Surfaces for combustion chamber of internal combustion engine having controlled fuel injection

In an internal combustion engine with controlled ignition, including at least a cylinder closed by a cylinder head, a piston reciprocating in the cylinder in a cycle between a top dead centre and a bottom dead centre, a main chamber and a prechamber forming a high turbulence combustion chamber, a fuel injector and a controlled ignition device, and means for controlling injection of the fuel so as to greatly increase the advance with the load on the engine, wherein the prechamber is formed in the cylinder head and the fuel injector and the controlled ignition device emerge into the prechamber, the improvement wherein the main chamber includes adjacent elementary chambers formed at least in the cylinder head, the lower face of the cylinder head extending between said elementary chambers and the upper face of the piston forming an impelling surface surrounding the prechamber, the inlets of the chamber and prechamber opening into the impelling surface without throttle between the prechamber, the elementary chambers, and the main chamber during the complete cycle of the piston, whereby due to the absence of throttle between the prechamber and the main chamber and between the prechamber and the elementary chambers, and the cooperation of the fuel controlled injection means, the combustion on low load is confined within the prechamber by a free circulation of air from the elementary chambers into the prechamber under the action of the piston arriving at top dead centre, and the combustion on high load spreads out freely from the prechamber into the elementary chambers as the piston goes down from top dead centre.