To simultaneously reduce NOX and particulates produced in a diesel engine.
The engine revolution number of a diesel engine and an engine load (indicated by axle opening in the drawing) are detected, a time for closing an exhaust valve is made variable, the exhaust valve is closed before an air intake valve closes and a time for closing the exhaust valve is made earlier when the engine revolution number and the engine load are more reduced. Thus, the generation of particulates is reduced by causing burnt gas of a high temperature remaining in a cylinder to keep the temperature of the cylinder high in the region of the low revolution and low load of the diesel engine and the generation of NOX is controlled by lowering a combustion highest temperature by the effect of the thermal capacity of the remaining burnt gas.
OSHIMA KENJI
ITO MASAHARU
SEKIGUCHI KIYONORI
SAKAKIBARA YASUYUKI
