Combustion and Emission Characteristics of Dimethyl Ether in Compression Ignition Engines

Dimethyl ether (DME) has emerged as a promising alternative to conventional diesel in compression ignition (CI) engines owing to its unique chemical structure and favourable physical properties. With an inherent oxygen atom in its molecular formula, DME enables near-smokeless diffusion combustion and significantly reduces particulate emissions without extensive after-treatment. Its high cetane number ensures rapid ignition, while the absence of carbon–carbon bonds limits soot precursor formation. Engine modifications such as specialised injectors, altered combustion chamber geometry and optimised fuel-supply systems are typically required to accommodate DME’s low viscosity and high vapour pressure. The integration of exhaust gas recirculation (EGR) strategies further curbs nitrogen oxide (NOx) formation by lowering peak combustion temperatures. Both heavy-duty and passenger vehicle studies have demonstrated that DME can match or exceed diesel engine performance while achieving substantial reductions in regulated pollutants. Numerical simulations have also explored low-temperature combustion modes, such as homogeneous charge compression ignition (HCCI) and partially premixed combustion, to exploit DME’s fast reactivity for enhanced thermal efficiency and ultra-low emissions. Production pathways from renewable feedstocks, including biomass and captured CO2, underscore the global potential of DME to decarbonise transport sectors and meet tightening emissions regulations.

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Combustion and Emission Characteristics of Dimethyl Ether in Compression Ignition Engines publication trend

The graph below shows the total number of articles in combustion and emission characteristics of dimethyl ether in compression ignition engines across all publications each year (not limited to Nature Index journals).

Technical terms

Dimethyl ether (DME): An oxygenated fuel (CH3–O–CH3) with high cetane number and low viscosity, enabling clean combustion in CI engines.

Compression ignition (CI): A combustion process in which fuel ignites under high temperature and pressure without a spark.

Cetane number: A measure of a fuel’s ignition quality, indicating how readily it auto-ignites under compression.

Exhaust gas recirculation (EGR): A technique that routes a portion of exhaust gases back into the intake to reduce combustion temperatures and NOx formation.

NOx emissions: Nitrogen oxides formed at high combustion temperatures, regulated due to their role in air pollution and ozone formation.

Soot (particulate matter): Solid carbonaceous particles produced during fuel-rich combustion zones, harmful to health and regulated by emissions standards.

References

1. The potential of dimethyl ether (DME) to meet current and future emissions standards in heavy-duty compression-ignition engines. Fuel (2024).
2. Numerical investigation on the use of Dimethyl Ether (DME) as an alternative fuel for compression-ignition engines. Fuel (2023).
3. Combustion Performance and Low NOx Emissions of a Dimethyl Ether Compression-Ignition Engine at High Injection Pressure and High Exhaust Gas Recirculation Rate. Energies (2022).