To provide a lean burn internal combustion engine capable of realizing consistent combustion, reducing NOx emission, and enhancing the fuel consumption.
A lean burn internal combustion engine comprises a fuel injection valve to inject fuel in an air intake passage, a control means to control the injection timing by the fuel injection valve so that a part of fuel required according to the running condition is injected before an air intake valve is opened, and the remaining fuel is injected after the air intake valve is opened, and a piston in which the remaining fuel injected after the air intake valve is opened is stored in a cavity formed in a top surface of the piston, the fuel/air mixture is formed within the cavity, and the fuel/air mixture is lead in a vicinity of an ignition plug in the second half of the compression stroke. The fuel/air mixture of the air-fuel ratio lower than the homogeneous fuel/air mixture formed over the entire combustion chamber is formed in the cavity, and led in a vicinity of the ignition plug in the second half of the compression stroke, and consistent combustion can be realized. NOx emission and the fuel consumption can be reduced by adequately controlling the air-fuel ratio.
MOGI KAZUHISA
OTA TOKUJI
Hidemi Matsukura
Yutaka Nagata
Kazunobu Sera
Tsutomu Toyama
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