To impart the fuel consumption improving effect by lean combustion; and to expand a traveling area for obtaining the effect.
Burnt gas is exhausted from exhaust stroke side preceding cylinders 2A and 2D between a pair of cylinders overlapping in an exhaust stroke and an intake stroke, and is introduced as it is into intake stroke side succeeding cylinders 2B and 2C via a gas passage 22 between the cylinders, and only gas exhausted from the succeeding cylinders 2B and 2C is introduced into an exhaust passage 20. Combustion is performed in the lean air fuel ratio larger by a prescribed quantity than the theoretical air fuel ratio in the preceding cylinders 2A and 2D, and the combustion is performed by supplying fuel to the burnt gas introduced from the preceding cylinders 2A and 2D in the succeeding cylinder 2B and 2C. Fuel supply to a prescribed cylinder is stopped in the prescribed timing when an air-fuel mixture temperature of the succeeding cylinders 2B and 2C is a relatively high state.
HITOMI MITSUO
SUMITA KOJI
HAYASHI YOSHINORI
ARAKI KEIJI
Kyuichi Ueki
Jiro Higuchi