(NOx) (SOx)2016 (EGR) (SCR) NOx NOx (UHC) NOx 25 ( ) CO 2 ( ) (Gas Permeation Membrane; GPM) 1 GPM GPM (2 ) (Anti-Quenching Membrane; AQM) GPM 2 (Oxygen Enriched Air; )1 (Nitrogen Enriched Air; NEA) NEA 2 AQM NEA NOx AQM NEA Compressor NEA 1 AQM (1) AQM OEM AQM 1 2 1 ; GT-Power (Gamma Technologies ) GPM 1 AQM 1 Engine type Ignition / Combustion Bore Stroke Rated speed Back press. Reduction (BPR) NEA cooler Compressor 4 st. cycle, inline 6 cyl. Pilot ign./ Premixed lean-burn 200 mm 300 mm 900 rpm Comp. ratio 14.2 Orifice cooler Base gas engine NEA intake valve intake valve Pilot fuel Main gas fuel BMEP Air excess factor Exhaust valve Gas oil Natural gas (Town gas) 2.0 MPa 1.8 2.0 Turbine #1 Exhaust 6cylinders Turbine #2 2 AQM (2) AQM NEA 2 3
(Rapid Compression- Expansion Machine; RCEM) 3D-CFD ; FIRE (AVL ) NEA (Particle Image Velocimetry; PIV) RCEM ( ) RCEM 2 (RCEM) Base engine Bore Stroke Con rod length Clearance volume 4stroke cycle, 1cyl. 240 mm 260 mm 520 mm 240 mm h50 mm Compression ratio 6.0 Engine speed Quartz window 300 rpm 125 mm t62 mm 3 AQM RCEM (3) 3D-CFD ; KIVA-3V(ERC ); SENKIN AQM Gas Research Institute GRI-Mech 3.0 3 KIVA-3V SENKIN 4 1 60 3 KIVA-3V SENKIN Primary: Blob method, Droplet breakup Secondary: KH-RT model NO generation Comb. scheme Extended Zeldovich mechanism n-heptane: ERC Diesel methane: GRI 3.0 (SP:53, RC:325) Initial layer thickness 10 20 mm 45,000 cells @ 70 CA BTDC 4 (4) RCEM 5 2 mm 207 mm (240 mm50 mm) 2 NEA (CO, CO2, UHC, NOx, O2) NEA 21 vol.% NEA mixture mixture Spark plug Spark gap Thin wall bulkhead Swirler Constantvolume chamber 5 (5) RCEM AQM 4 NEA RCEM AQM NEA
4 RCEM Gas fuel / pilot fuel Comp. condition Pilot injection (CA: crank angle) Pure methane / Gas oil (JIS#2) Temp. 780 K, Press. 8.0 MPa Pressure: 90 MPa Timing: -8.5 CA ATDC Duration: 10 CA Mixture condition of premixed lean-burn experiments O 2 vol. concentration Homogeneous (19%, 21%, 25%) Excess air factor: 1.9 3.2 Mixture condition of AQM experiments O 2 vol. concentration Ref. Homogeneous, O 2 21%, = 2.1 O O 2 vol. concentration AQM 2 19 % + 25 % (ave 21%), NEA/ 3.0 (1) 6 GPM GT-Power NEA 2 ( =0) AQM GPM NEA (25% ) NEA 86%AQM 25% GPM 30% GPM2 = 25% AQM 6 AQM (2) RCEM AQM 5 RCEM AQM NEA 40 CA 65 CA NEA 61 CA 21.8 vol.% 8 PIV RCEM RCEM AQM 5 AQM 時の給気 燃料供給条件 ( RCEM) Compression-end pressure Swirl velocity [m/s] Charge temperature 30 25 20 15 10 5 @ TDC 8 MPa 240 C intake valve Main (NEA) Sub () O 2 vol. concentration 19 % 25% open timing 220 CA BBDC 230 CA BBDC duration 230 CA port pressure 1.25 MPa 2.7 MPa Main intake valve @65 CA BTDC Sub intake @40 CA BBDC 20.7 21.0 21.5 valve O 2 concertation vol.% 7 RCEM AQM Reference 0-120 -80-40 0 40 80 120 Radial position in measurement plane [mm] 8 RCEM
(3) ( =1.8) NEA (O 2 =21 vol.%) 6 9 UHC ( ) NO UHC 60% NO 12.5% CFD AQM 6 AQM layer thickness [mm] O 2 concentration [vol.%] 0 (Ref.) (21) 10 29 15 27 Ref. 10mm 20mm Methane concentration 0 1.5 3.0 [mass%] 20 25 UHC [ppm] 1042 934 978 991 Methane slip [%] 1.85 1.10 1.06 0.71 NO increase [%] - 3.0 5.4 12.5 9 AQM (@80 CA ATDC) AQM 25 60% NOx NEA AQM AQM 7 AQM Ref AQM #1 AQM #2 Methane supply [mol] 0.079 0.086 0.082 Rate of heat release [MJ/s] UHC [ppm] 3578 1285 2622 CO 2 [%] 9.15 10.21 9.44 CO [ppm] 211 136 141 NOx [ppm] 874 718 860 0.8 0.6 0.4 0.2 0 Ref. AQM #1 0 100 200 300 400 Time after spark ignition [ms] 10 (5) RCEM AQM 11 19, 21, 25 vol. % : =1.90 3.15 ( ) (4) =1.3 7 10 (O 2 =21 vol.%) 2 AQM (O 2 =19/25 vol.%) 11 RCEM
=2.4 NO 2 8 12 =2.0 ( ) AQM =2.0 RCEM AQM =1.8 RCEM AQM 10% AQM NEA 10% AQM AQM 10% 25% NO 30% RCEM NOx AQM 8 RCEM AQM Ref KL AQM_ 2 AQM KL Air excess factor [-] 2.0 1.8 In-cylinder press. [MPa] Rate of heat release [MJ/s] UHC [ppm] 3191 2929 2456 CO 2 [%] 5.37 5.33 5.86 CO [ppm] 1375 1851 1292 NOx [ppm] 1323 1202 1759 20 15 10 5 7 6 4 2 12 RCEM Ref. KL AQM KL AQM_ 2 0-10 TDC 10 20 30 40 Crank angle [deg. ATDC] B. Lewis, G. von Elbe, Combustion Flames and Explosions of Gases, 3rd edition, p268, ACADEMIC PRESS, INC. T. Shudo, K. Shimamura, Y. Nakajima Combustion and emissions in a methane DI strati1ed charge engine with hydrogen pre-mixing. JSAE Rev 2000; 21: 3 7 H. Ohno, et al., Development of a Nitrogenenrichment /Humidification Membrane System For NOx Emission reduction For Marine Diesel Engines, Proc. ISME Kobe, 2011, C6-3.,, GPU,, 49 6, 2014, pp.125-131. H. Tajima, D. Tsuru, Reduction of Methane Slip from Gas Engines by O2 Concentration Control using Gas Permeation Membrane, Proc. SAE/KSAE PFL Meeting, 2013, pp.1-8. H. Tajima, D. Tsuru, Potential Investigation of PCCI Combustion as NOx Reduction Measure at Low-load Operation with Low- CN LCO Fuel, Proc. CIMAC Congress 13 Shanghai, 2013, pp.1-10.,,, 21 72, 2012, pp.4-11.,,, 52, 2014,. H. Tajima, Methane slip reduction from natural gas engines by oxygen stratification using gas permeation membrane, THIESEL 2014, Universitat Politecnica de Valencia, Spain.,,, 24, 2013,. 九州大学 総合理工学研究院 准教授 九州大学 総合理工学研究院 教授 九州大学 総合理工学研究院 助教