| 摘要 |
PURPOSE:To hasten mixing with air to make complete combustion and to reduce NOX by making initial combustion progress with excessively dense mixture and injecting inert materials which are not directly related to combustion toward the fuel spray near the side wall of a combustion chamber. CONSTITUTION:A center injection type direct injection diesel engine is recessedly provided with a combustion chamber 2 not forming air swirl at a nearly center on the top face of a piston 1. A fuel injection valve 4 having a plurality of injection holes of a cylinder head is arranged at the center of the combustion chamber 2. In the constitution mentioned above, a plurality of inert material injection valves 6a to 6d, which inject inert materials 7, which is not directly relate to combustion, at a position near the side wall of the combustion chamber 2 in the direction along the side wall face of the combustion chamber 2, are arranged. Fuel spray 5 progresses in a state that initial combustion is made with excessively dense air-fuel mixture. At the time when fuel spray 5 develops near the side wall of the combustion chamber 2, inert materials 7 is injected to hasten the mixing with air.
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