Investigations on the Knocking Propensity of LNG by Engine Tests and Reaction Kinetics Peter Eilts and Kai Moshammer, 5 November 2018
Outline Part 1 (Engine Tests) Introduction Experimental Procedure Results Conclusions 5 November 2018 Peter Eilts ivb Slide 2
Outline Part 1 (Engine Tests) Introduction Experimental Procedure Results Conclusions 5 November 2018 Peter Eilts ivb Slide 3
Introduction Methane Number The Methane Number (MN) of a gas is defined as the percentage of Methane in a mixture of Methane and Hydrogen which has the same knocking behaviour as the gas to be investigated in a defined test engine under defined operating conditions. It was developed by AVL in the late 19s. There are several correlations available to calculate the MN from the gas composition. Unfortunately they can give widely differing results. 5 November 2018 Peter Eilts ivb Slide 4
Introduction Methane Number The MN can only be measured with the equipment used by AVL during the development of the method, just like the RON and MON can only be measured with a CFR engine. Unfortunately this equipment is not available anymore. If a different engine or different operating conditions are employed the results are different. The result is called the Service Methane Number (SMN). 5 November 2018 Peter Eilts ivb Slide 5
Introduction Service Methane Number The Service Methane Number (SMN) of a gas is defined as the percentage of Methane in a mixture of Methane and Hydrogen which has the same knocking behaviour as the gas to be investigated in an arbitrary engine under arbitrary operating conditions. The SMN shows the same tendencies as the MN, but different absolute values. For mixtures of Methane and Hydrogen the SMN is equivalent to the MN. 5 November 2018 Peter Eilts ivb Slide 6
Introduction Service Methane Number 5 November 2018 Peter Eilts ivb Slide 7
Outline Part 1 (Engine Tests) Introduction Experimental Procedure Results Conclusions 5 November 2018 Peter Eilts ivb Slide 8
Experimental Procedure Engine 1 Externally supercharged 1-cylinder 4-stroke SI-engine with a displacement of 0 ccm. Compression ratio 12.5:1. Gas injection in the intake pipe ( 2 gas injectors) Stoichiometric operation Cylinder pressure sensor Kistler 61B Charge amplifier Kistler 11 Kistler KiBox Tests carried out at 2000 rpm 5 November 2018 Peter Eilts ivb Slide 9
Experimental Procedure Engine 2 Externally supercharged 1-cylinder 4-stroke SI-engine with a displacement of 200 ccm. Compression ratio 12.5:1. Gas injection in the intake pipe Stoichiometric operation Cylinder pressure sensor Kistler 43A Charge amplifier Kistler 11 Kistler KiBox Tests carried out at 2000 rpm 5 November 2018 Peter Eilts ivb Slide 10
Experimental Procedure Test Gases 5 November 2018 Peter Eilts ivb Slide 11
Experimental Procedure Possibilities investigated to determine the SMN Knock-limited charge air pressure: p ch -SMN Knock-limited IMEP: IMEP-SMN Knock-limited MFB: MFB-SMN 5 November 2018 Peter Eilts ivb Slide 12
Outline Part 1 (Engine Tests) Introduction Experimental Procedure Results Conclusions 5 November 2018 Peter Eilts ivb Slide 13
Results Calculated Methane Numbers 5 November 2018 Peter Eilts ivb Slide 14
Results p ch -SMN and IMEP-SMN vs. MWM-MN, engine 1 R² = 0.9519 R² = 0.9643 p_ch SMN MFB=8 CA p_ch SMN MFB=14 CA Linear (MFB=8 CA) Linear (MFB=14 CA) MWM MN MWM MN R² = 0.98 R² = 0.92 IMEP SMN MFB=8 CA Linear (MFB=8 CA) IMEP SMN MFB=14 CA Linear (MFB=14 CA) MWM MN MWM MN 5 November 2018 Peter Eilts ivb Slide 15
Results p ch -SMN and IMEP-SMN vs. MWM-MN, engine 2 R² = 0.9896 R² = 0.9735 p_ch SMN MFB=8 CA p_ch SMN MFB=14 CA Linear (MFB=8 CA) Linear (MFB=14 CA) MWM MN MWM MN R² = 0.9898 R² = 0.9579 IMEP SMN MFB=8 CA Linear (MFB=8 CA) IMEP SMN MFB=14 CA Linear (MFB=14 CA) MWM MN MWM MN 5 November 2018 Peter Eilts ivb Slide 16
Results MFB-SMN vs. MWM-MN, engine 1 and 2 R² = 0.9624 R² = 0.9848 MFB SMN Engine 1 Linear (Engine 1) MFB SMN Engine 2 Linear (Engine 2) MWM MN MWM MN 5 November 2018 Peter Eilts ivb Slide 17
Results p ch -SMN vs. calculated MN, engine 1 R² = 0.9698 R² = 0.9541 p_ch SMN MFB=10 CA p_ch SMN MFB=10 CA Linear (MFB=10 CA) Linear (MFB=10 CA) NPL MN DGC MN R² = 0.9633 R² = 0.9625 p_ch SMN MFB=10 CA p_ch SMN MFB=10 CA Linear (MFB=10 CA) Linear (MFB=10 CA) MWM MN PKI MN 5 November 2018 Peter Eilts ivb Slide 18
Results p ch -SMN vs. calculated MN, engine 1 R² = 0.9213 R² = 0.95 p_ch MN MFB=10 CA p_ch SMN MFB=10 CA Linear (MFB=10 CA) Linear (MFB=10 CA) GRI linear MN Wärtsilä MN R² = 0.9214 p_ch SMN Cummins MN MFB=10 CA Linear (MFB=10 CA) 5 November 2018 Peter Eilts ivb Slide 19
Outline Part 1 (Engine Tests) Introduction Experimental Procedure Results Conclusions 5 November 2018 Peter Eilts ivb Slide 20
Conclusions Service Methane Numbers were measured on two engines for 11 gases with three methods The results were compared to seven calculation methods for the Methane Number In all cases the measured SMNs showed different absolute values but the same trends as the calculated MNs The coefficients of determination for the correlations between measured SMNs and calculated MNs mainly depend on the calculation method 5 November 2018 Peter Eilts ivb Slide 21
Reaction Kinetics 5 November 2018 Peter Eilts ivb Slide 22