High Load Lean SI-combustion Analysis of DI Methane and Gasoline using Optical Diagnostics with Endoscope Chalmers Univ of Technology

Format:

Book

Conference/Event

Author/Creator:

Clasen, Kristoffer, author.

Contributor:

Dahlander, Petter

Koopmans, Lucien

Melaika, Mindaugas

Conference Name:

15th International Conference on Engines & Vehicles (2021-09-12 : Capri, Italy)

Language:

English

Physical Description:

1 online resource cm

Place of Publication:

Warrendale, PA SAE International 2021

Summary:

Homogeneous lean spark-ignited combustion is known for its thermodynamic advantages over conventional stoichiometric combustion but remains a challenge due to combustion instability, engine knock and NOx emissions especially at higher engine loads (>10 bar IMEP). Investigations have shown that lean combustion can partly suppress knock, which is why the concept may be particularly advantageous in high load, boosted operation in downsized engines with high compression ratios. However, the authors have previously shown that this is not true for all cases due to the appearance of a lean load limit, which is the convergence of the knock limit and combustion stability limit. Therefore, further research has been conducted with the alternative/ renewable fuel methane which has higher resistance to auto-ignition, hence theoretically eliminating the knock limit. Operation with gaseous fuel on high load was achieved by high pressure direct injection and boosting in a single cylinder research engine. To better investigate the combustion, an endoscope allowing optical access to the combustion chamber was utilized. High load lean operation with methane could confirm the hypothesis that without a knock limit, optimal ignition timing could be maintained resulting in high combustion stability, hence the high load lean limit was eliminated. Instead, limitation was reached due to peak cylinder pressure. DI-methane resulted in stable combustion like gasoline, but methane provided an overall lower fuel conversion efficiency by 1-2 %-units compared to gasoline. Alternative injection strategies and high energy ignition were investigated to find potential means of improving the efficiency of methane combustion and to understand the difference in efficiency compared to gasoline

Notes:

Vendor supplied data

Publisher Number:

2021-24-0046

Access Restriction:

Restricted for use by site license