Emission characterization on a CAT3410 engine

Objective

To simulate the CAT 3410 engine using diesel fuel and characterize the emission for open W piston and Omega Piston.

Simulation

The geometry has been modified making it less heavy computationally. The given geometry has been transformed for sector simulation of 60deg. Converge sector surface creation tool has been used for both of the piston.

Open W piston

Omega Piston

Sector geometry of both the pistons

Open W piston

Omega Piston

Crank Angle – based IC engine simulation has been chosen as the application type.

The length of stroke is specified as 0.1651m. Depth of bore is 0.13716m, the specified rpm is 1600 and connecting rod length is 0.263m.

Materials

Run Parameters:

Regions:

All the boundaries were assigned to the same regions.

Boundary Conditions:

Piston

Front Face

Cylinder head

Cylinder wall

Spray Modelling:

Combustion modelling

Turbulence Modelling

Default Rans k-epsilon model has been used.

Grid Control:

Cubic element of size 0.004 m has been used as default element size.

Adaptive Mesh Refinement:

Embedding

Results and Discussion

Pressure Vs Crank Angle

As it can be observed from the plot, the peek pressure for Omega piston is marginally higher than that of Omega piston.

Mean Temperature Vs Crank Angle

Mean temperature is higher in case of Omega type of piston as compared to that of open W type. Since the volume reduction for both the cases are same, it may relate to the unburnt particles in cylinder in case of open W type piston.

Integrated Heat Release Rate

From the above plot, open W piston has less integrated heat output than the omega type piston.

Emission analysis

Comparison of Soot Formation

Comparison of NOx Formation

Comparison of CO formation

Comparison of CO2 formation

Comparison of Unburnt Hydrocarbons

Conclusions:

W piston has more soot formation, whereas much lower NOx formation. Also, open W piston has more CO emission as compared to omega piston. Omega piston has higher Co2 formation as compared to open W piston. Omega piston has slightly less unburnt fuel.

IMEP and Power Calculation

Engine Performance for Omega and W Piston

W piston

Power(P) = (2 * pi * N * T)/60

N = 1600rpm

~ 9600 deg/sec

Time taken to traverse 270.16 deg = 270.16/9600s = 0.028s

Power = Gross Work / time

• 846J/0.028 = 17.065Kw

Torque = (17065*60)/(2*3.14*1600) = 101N-m

Omega piston

Power = Gross Work / time

• 053j/0.028s = 19.609kw

Torque = (19609*60)/(2*3.14*1600) = 117N-m

Based on the above calculation and characteristics, Omega Shaped piston is more advantageous in both emission as well as power output.

Adaptive Mesh Refinement Simulation

Omega Piston Temeperature Simulation

Omega Piston NOX Simulation

Omega Piston CO Simulation

Open W piston Temperature Simulation

Open W Piston NOX simulation

Open W CO Simulation