To quickly vaporize injected fuel by making a sub-combustion chamber of a material having lower thermal conductivity than the material composed of a main combustion chamber in a fuel injection type internal combustion engine having a fuel-air mixture opening/closing valve and an ignition plug in the sub-combustion chamber communicating with the main combustion chamber.
A sub-combustion chamber 9 communicates with a main combustion chamber 8 and a main fuel injection valve 31 is fixed to an accumulating chamber 21 above a fuel-air mixture opening valve 70 fixed to the sub- combustion chamber 9. A hole 4a is made in the cylinder head 4 at the center of the cylinder 3a and a bottom case 61 is fitted in the hole 4a and a top case 62 is overlaid on the bottom case 61 to form the sub-combustion chamber 9 with a space 61a opening above the bottom case 61 and a portion communicating with the main combustion chamber 8. These top case 61 and bottom case 62 have lower thermal conductivity than a cylinder block 3 and the cylinder head 4 and hence can keep the inside of the sub-combustion chamber 9 at high temperatures.
TSUSHIMA YUJI
YAMASHITA HIROSHI
TAKADA YOSHIHIRO
