1. Date of download: 6/21/2016 Copyright © ASME. All rights reserved. From: Lean Partially Premixed Combustion Investigation of Methane Direct-Injection Under Different Characteristic Parameters J. Energy Resour. Technol. 2014;136(2):022202-022202-7. doi:10.1115/1.4026204 Injection duration setting for various (a) hydrogen fractions and (b) diluent fractions as a function of equivalence ratio Figure Legend:

2. Date of download: 6/21/2016 Copyright © ASME. All rights reserved. From: Lean Partially Premixed Combustion Investigation of Methane Direct-Injection Under Different Characteristic Parameters J. Energy Resour. Technol. 2014;136(2):022202-022202-7. doi:10.1115/1.4026204 Methane distribution around the spark discharge location at two different spark delay times (a) T sd = 1 ms and (b) T sd = 5 ms at equivalence ratio of 0.6 Figure Legend:

3. Date of download: 6/21/2016 Copyright © ASME. All rights reserved. From: Lean Partially Premixed Combustion Investigation of Methane Direct-Injection Under Different Characteristic Parameters J. Energy Resour. Technol. 2014;136(2):022202-022202-7. doi:10.1115/1.4026204 Effect of injection pressure on peak pressure and maximum rate of pressure rise at chamber pressure of 1 bar, chamber temperature of 298 K and spark delay time of 1 ms for equivalence ratios of 0.6, 0.8 and 1.0 Figure Legend:

4. Date of download: 6/21/2016 Copyright © ASME. All rights reserved. From: Lean Partially Premixed Combustion Investigation of Methane Direct-Injection Under Different Characteristic Parameters J. Energy Resour. Technol. 2014;136(2):022202-022202-7. doi:10.1115/1.4026204 Effect of injection pressure on initial combustion duration at different spark delay times at chamber pressure of 1 bar and chamber temperature of 298 K for equivalence ratios of 1.0 and 0.6 Figure Legend:

5. Date of download: 6/21/2016 Copyright © ASME. All rights reserved. From: Lean Partially Premixed Combustion Investigation of Methane Direct-Injection Under Different Characteristic Parameters J. Energy Resour. Technol. 2014;136(2):022202-022202-7. doi:10.1115/1.4026204 Effect of chamber temperature and chamber pressure on peak pressure at injection pressure of 90 bar, spark delay time of 1 ms and equivalence ratios of 0.6, 0.8, and 1.0 Figure Legend:

6. Date of download: 6/21/2016 Copyright © ASME. All rights reserved. From: Lean Partially Premixed Combustion Investigation of Methane Direct-Injection Under Different Characteristic Parameters J. Energy Resour. Technol. 2014;136(2):022202-022202-7. doi:10.1115/1.4026204 Effect of chamber temperature and chamber pressure on maximum rate of pressure rise at injection pressure of 90 bar, spark delay time of 1 ms and equivalence ratios of 0.6, 0.8, and 1.0 Figure Legend:

7. Date of download: 6/21/2016 Copyright © ASME. All rights reserved. From: Lean Partially Premixed Combustion Investigation of Methane Direct-Injection Under Different Characteristic Parameters J. Energy Resour. Technol. 2014;136(2):022202-022202-7. doi:10.1115/1.4026204 Effect of chamber temperature and chamber pressure on main combustion duration at injection pressure of 90 bar, spark delay time of 1 ms and equivalence ratios of 0.6, 0.8, and 1.0 Figure Legend:

8. Date of download: 6/21/2016 Copyright © ASME. All rights reserved. From: Lean Partially Premixed Combustion Investigation of Methane Direct-Injection Under Different Characteristic Parameters J. Energy Resour. Technol. 2014;136(2):022202-022202-7. doi:10.1115/1.4026204 Effect of hydrogen addition on flame propagating process at four different times after spark ignition (1.0, 2.4, 3.9, and 5.4 ms), injection pressure of 90 bar, spark delay time of 1 ms and equivalence ratio of 0.8 Figure Legend:

9. Date of download: 6/21/2016 Copyright © ASME. All rights reserved. From: Lean Partially Premixed Combustion Investigation of Methane Direct-Injection Under Different Characteristic Parameters J. Energy Resour. Technol. 2014;136(2):022202-022202-7. doi:10.1115/1.4026204 Effect of hydrogen addition on peak pressure and maximum rate of pressure rise at injection pressure of 90 bar, chamber pressure of 1 bar, chamber temperature of 298 K and spark delay time of 1 ms for equivalence ratios of 0.6, 0.8, and 1.0 Figure Legend:

10. Date of download: 6/21/2016 Copyright © ASME. All rights reserved. From: Lean Partially Premixed Combustion Investigation of Methane Direct-Injection Under Different Characteristic Parameters J. Energy Resour. Technol. 2014;136(2):022202-022202-7. doi:10.1115/1.4026204 Effect of hydrogen addition on main combustion duration and NOx concentration at injection pressure of 90 bar, chamber pressure of 1 bar, chamber temperature of 298 K and spark delay time of 1 ms for equivalence ratios of 0.6, 0.8, and 1.0 Figure Legend:

11. Date of download: 6/21/2016 Copyright © ASME. All rights reserved. From: Lean Partially Premixed Combustion Investigation of Methane Direct-Injection Under Different Characteristic Parameters J. Energy Resour. Technol. 2014;136(2):022202-022202-7. doi:10.1115/1.4026204 Effect of diluent addition on peak pressure at injection pressure of 90 bar, chamber pressure of 1 bar, chamber temperature of 298 K and equivalence ratios of 0.6, 0.8, and 1.0 for different spark delay times Figure Legend:

12. Date of download: 6/21/2016 Copyright © ASME. All rights reserved. From: Lean Partially Premixed Combustion Investigation of Methane Direct-Injection Under Different Characteristic Parameters J. Energy Resour. Technol. 2014;136(2):022202-022202-7. doi:10.1115/1.4026204 Snapshots of combustion instability as a function of time after spark in diluent fraction of 25%, spark delay time of 40 ms and equivalence ratio of 1.0 Figure Legend:

13. Date of download: 6/21/2016 Copyright © ASME. All rights reserved. From: Lean Partially Premixed Combustion Investigation of Methane Direct-Injection Under Different Characteristic Parameters J. Energy Resour. Technol. 2014;136(2):022202-022202-7. doi:10.1115/1.4026204 Effect of diluent addition on maximum rate of pressure rise, main combustion duration and NOx concentration at injection pressure of 90 bar, chamber pressure of 1 bar, chamber temperature of 298 K and spark delay time of 110 ms for equivalence ratios of 0.6, 0.8, and 1.0 Figure Legend: