Abstract
The relation of exhaust smoke and the improvement of specific fuel consumption are the most important requirement in a diesel engine. To realize these two items, the characteristics of fuel spray were investigated using a model chamber which had the same shape of piston crown as that of real engine. Spray tip penetration and spray cone angle were measured from 16mm high-speed photography.
With reference to these results, relation between exhaust smoke and combination of shape of piston crown and injection angle of spray were investigated in an operated engine. The combination has a greater effects on the smoke at low load than that at high load.
From the examinations, the smoke reduction, especially at low load, could be reached by decreasing mean equivalence ratio in fuel spray at the moment of impinging on the piston wall and by designing the piston bowl considering the spray does not hit the cylinder liner wall.
