The peak temperature during the combustion near TDCF results 100 K higher in the case of coated piston, ensuring a reduction of heat losses through it.
The results clearly indicate that anodized aluminum coating presents higher temperature near to the TDCF, producing a greater potential in heat loss reduction during combustion.
The causes are the large piston surface exposed to the hot gas near the TDCF and the high HTC and gas temperature near the piston, due to the combustion in the bowl.
From Figure 19 it comes out that Flow model overestimates the HTC near to TDCF due to the model dependence on gas velocity, swirl and turbulence.
It can be clearly seen from the zoomed-in view of the plot that the existing model predicts the right levels of turbulence near TDCF. However modern engines utilizing strategies such as early injection require accurate turbulence levels during the intake and early compression stroke.
The increase in turbulence levels with a reduction in maximum valve lift is clearly seen during the intake process, while the reduction in tumble results in lower levels of turbulence close to TDCF. The plot of tumble number, shown in Figure 16, clearly shows the reduction in tumble number with lower valve lifts.
This can also be observed from Figure 6(c) which compares the turbulent kinetic energy values at TDCF.
TDCf (rpm = 2000 = const., [p.sub.Rail] = 10.0 MPa).
TDCf, the results with SO[I.sub.300] have higher gradients compared to the results performed with SO[I.sub.260].