The effects of nozzle diameter (0.12~0.32mm) and ambient temperature (550~850K) on the spray characteristics of heavy duty diesel engines were measured visually in a constant volume combustion chamber using the Mie scattering and shadowgraph methods. The results showed that

different from the light duty diesel engines

the liquid phase fuel of the heavy duty diesel engines with the 0.32mm nozzle still penetrated continuously and failed to reach a quasi steady state when the ambient temperature was increased to 750K at various injection pressures and ambient pressures

or when reaching a quasi steady state

the penetration distance was too long

leading to spray impingement. With the increase of the ambient temperature

the adhesion amount of liquid spray with the 0.32mm nozzle decreased. Only when the evaporation of fuel was strong enough at the ambient temperature of 850K

could the height and radius of impingement spray reach a quasi steady state.