Experimental and kinetic modeling study on auto-ignition of oxymethylene ethers (OME1 and OME2) at engine-relevant pressures
(2026) Combustion and Flame — (2026)
Files
OMEs_IDT.pdf
Closed Access - Adobe PDF
- 560.96 KB
Details
- Authors
- Abstract
- This study investigates the auto-ignition of oxymethylene ethers (OMEs) as sustainable energy carriers, addressing the lack of kinetic data at engine-relevant pressures. Ignition delay times (IDTs) for OME 1 and, for the first time, OME 2 were measured at pressures at 20 bar and 40 bar, covering temperatures of 900-1350 K and equivalence ratios of 0.5, 1.0, and 2.0. A detailed kinetic mechanism, UCL-hp, was developed and validated against these new datasets. The results elucidate the coupled effects of pressure, temperature, equivalence ratio, and chain length on IDTs of OME 1 and OME 2. Specifically, OME 2 exhibits higher reactivity than OME 1 due to its longer chain length facilitating peroxy-driven branching. While increasing pressure and temperature uniformly accelerate ignition, OME 2 shows a stronger sensitivity to the equivalence ratio than OME 1. A key finding is that high pressure significantly enhances low-temperature chemistry, shifting the kinetic flux from competitive radical consumption at 20 bar toward rapid chain-branching at 40 bar. Consequently, initial fuel-consumption reactions transition from inhibiting to promoting ignition as pressure escalates. Furthermore, OME 1 was observed to exhibit negative temperature coefficient (NTC) behavior at 40 bar. The UCL-hp mechanism accurately captures these pressure-dependent reactivity transitions and chain-length effects, providing a robust predictive tool for the optimization of high-pressure OMEs combustion in advanced compression-ignition engines. This work provides the first experimental validation of OME 2 auto-ignition at engine-relevant pressures up to 40 bar, filling a critical data gap in research on the ignition delay time of oxymethylene ethers. It is observed that low-temperature chemistry is significantly enhanced with increasing pressure, leading to a mechanistic shift where initial fuel-consumption pathways transition from inhibiting ignition at 20 bar to promoting it at 40 bar. Additionally, the discovery of pressure-induced NTC-like behavior in OME 1. By elucidating how pressure and chain length cooperatively shift the kinetic balance toward peroxy-driven pathways, this study enables more accurate predictions of ignition timing for sustainable e-fuels in high pressure engines.
- Affiliations
Citations
Huo, Y., Dias, V., Lefort, B., Do, H.-Q., Le Moyne, L., & Jeanmart, H. (2026). Experimental and kinetic modeling study on auto-ignition of oxymethylene ethers (OME1 and OME2) at engine-relevant pressures. Combustion and Flame. Submitted. https://hdl.handle.net/2078.5/277638 (Original work published 2026)