STRUCTURE OF COMBUSTION CHAMBER OF ENGINE

PURPOSE:To make efficient lean mixture combustion by a method wherein a combustion chamber is composed of a main chamber partitioned by the surface of piston and the inner wall of cylinder head, the first sub-chamber connected to the main chamber and the second sub-chamber connected to the first sub-chamber. CONSTITUTION:Swirl is produced both in the first sub-chamber 1B and the second sub- chamber 1C due to the squash flow within a compression stroke wherein a piston 4 is lifted up synchronously jetting fuel subject to specified characteristics out of a jetting nozzle 7 and another jetting nozzle 8 while in case of low and intermediate loading, a lean mixture and another mixture with air-fuel ratio optimum for ignition are respectively produced in the sub-chambers 1B and 1C. On the other hand, a flame ignited by an ignition plug 9 flows from the second communicating channel 6 to the sub-chamber 1B to ignite the fuel jetted from the jetting nozzle 7 along the swirl produced in the sub-chamber 1B spreading the flame from the first communicating channel 5 to the main combustion chamber 1A to start the lean mixture combustion. Besides, the fuel jetted from the fuel jetting nozzle 7 may be increased corresponding to the increase of loading to increase the engine output shifting from the layer combustion to the even mixture combustion as the high output combustion to cope with any high load operation.