PPC FOR LOW LOAD CONDITIONS IN MARINE ENGINE USING COMPUTATIONAL AND EXPERIMENTAL TECHNIQUES

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1 PPC FOR LOW LOAD CONDITIONS IN MARINE ENGINE USING COMPUTATIONAL AND EXPERIMENTAL TECHNIQUES Presented By:Kendra Shrestha Authors: K.Shrestha, O.Kaario, M. Imperato, T. Sarjovaara, M. Larmi Internal Combusion Engine Research Group Aalto University of Technology

2 Contents Partially Premixed Combustion (PPC) The Research Engine EVE Validation of the computational model Current injection system of EVE Combustion and Emission Analysis Conclusions

3 Partially Premixed Combustion PPC A compression ignited combustion process in which fraction of fuel is injected early so called the pilot injection followed by main injection close to TDC. Ignition delay is controlled to enhance better homogeinity of air-fuel mixture. PPC intend to endow better combustion with low NOx and Soot emissions. Problems with PPC Spray-Wall impingement Lubrication oil dilution resulting to the formation of unburnt HCs Objective of the study To Investigate the optimal conditions for the existing single cylinder EVE engine accompanying the PPC mode of combustion.

Engine Speed (rpm) 900 Nozzle orifice diameter (mm) 0.

4 Research Engine EVE Number of Cylinder 1 Stoke (mm) 280 Bore (mm) 200 Connecting Rod length (mm) 614 Number of valves 4 Engine Speed (rpm) 900 Nozzle orifice diameter (mm) 0.36 Number of nozzle holes 9 Inclusion angle Sector Mesh at TDC

Heat Release Rate (kj/deg) Heat Release Rate (kj/deg) In-cylinder Pressure (Bars) In-cylinder Pressure (Bars) Validation of Computational Model x 10 6 Validation Cases Single Injection Multiple

5 Heat Release Rate (kj/deg) Heat Release Rate (kj/deg) In-cylinder Pressure (Bars) In-cylinder Pressure (Bars) Validation of Computational Model x 10 6 Validation Cases Single Injection Multiple Injection Experimental Computational Experimental Computational Pilot Injection (SOI BTDC) - 30 Main Injection (SOI BTDC) Injection Quantity (gm/cycle) Total Lambda Injection Pressure (Bars) 1200 bars 1200 bars Nozzle -hole Diameter (mm) Combustion Model DARS-TIF DARS-TIF Gas at Exhaust Single Injection 20 Multiple Injection Experimental Simulation Experimental Simulation Crank Angle Crank Angle Single Injection Experimental Computational Crank Angle Crank Angle Multiple Injections Experimental Computational O2 (%-Vol) CO2(%-Vol)

6 Current Injection System SOI30 SOI35 SOI40 SOI45 Injection Pressure=1200bars Injection system:153x9x0.36

$EGR Gases O2 CO2 H2O CO H2 N2 EGR fraction 0.199493 2.59E-02 1.23E-02 6.$

7 Combustion and Emission Analysis Standard Piston Top Deeper Bowl Piston Top Implementation of Real EGR Basic Idea: EGR calculation is based on replacing the fresh charge by EGR gases. EGR Gases O2 CO2 H2O CO H2 N2 EGR fraction E E E E % EGR level

8 Combustion and Emission Analysis... Effect in soot formation due to piston bowl shape

9 Standard Piston Top 2 different injection settings are implemented keeping the case with current injection system (PPC 30) as baseline case. Total fuel injected=652gm/cycle Pilot injection=39% Total Lambda=2 SOMI =4 CAD BTDC CASES Injection Pressure (bars) Nozzle diameter(mm) Inc Angle SOPI (BTDC) PPC CASE 1A CASE 2A

10 Standard Piston Top... INC 153 INC 140

11 Standard Piston Top... 9x153x0.36 SOP-30 SOMI=-4 9x140x0.26 d=0.26 SOPI -30 SOMI-4

12 Deeper Bowl Piston Top Injection Details 9 holes cases 10 holes cases Inc Angle SOPI d=0.26 IMEP 360 % of fuel burnt d=0.22 IMEP 360 % of fuel burnt CASE 1B CASE 1C CASE 2B CASE 2C CASE 3B CASE 3C CASE 4B CASE 4C

14 SOPI -40 Yfuel scale (0-0.05) SOPI -25 Yfuel scale (0-0.05) SOPI -40 Spray visualization at SOPI 40 BTDC SOPI -25Spray visualization at SOPI 25 BTDC Effect of SOPI in mixture formation and spray wall impingement

15 9 holes vs 10 holes

16 Conclusions Difficult to maintain the condition accompanying the PPC with the conventional injection system. Piston position and the start of injection is the crucial parameter in determining good fuel-air mixture prior to combustion. Air fuel homogeneity is dependent on sweep of inclusion angle and increased injection pressure. 140 Inclusion angle was figured out to be an optimal inclusion angle favoring the PPC mode of combustion in the EVE. Piston bowl plays an essential role in determining good air-fuel mixture prior to combustion thus reducing soot emission. 9 holes injectors showed the better results as compared to the 10 holes injectors due to the increased momentum of single spray of 9 holes than that of 10 holes.

17 Normalized Emissions Percentage of fuel burnt Conclusions... 1, , ,80 0,60 0,40 0,20 BASELINE Standard bowl (CASE 1A EGR20%) Deeper Bowl (CASE 2B) BASELINE Standard Bowl (CASE1A EGR20%) Deeper Bowl (CASE 2B) 0,00 NOx CO Soot 80 With the injection optimization and implementation of EGR, NOx has been reduced by around 44%, CO by 60% and Soot by 66% in the standard piston top. The piston optimization resulted in more promising result with 58% reduction in NOx, 55% reduction in CO and 67% reduction in Soot.

18 Thank you for your attention!!!!

Partially Premixed Combustion (PPC) for low load conditions in marine engines using computational and experimental techniques

Aalto University School of Engineering Department of Energy Technology Kendra Shrestha Partially Premixed Combustion (PPC) for low load conditions in marine engines using computational and experimental