Methanol-gasoline blends in spark-ignition engines: A review of research progress and application prospects

Abstract

Spark-ignition engines remain widely used in passenger cars, motorcycles, hybrid vehicles, and light-duty transport, making fuel flexibility and emission reduction important during the transition to low-carbon mobility. Methanol-gasoline blends have attracted attention as alternative fuels because methanol has high oxygen content, high octane quality, strong charge-cooling capacity, and flexible production routes. This review summarizes recent progress in methanol-gasoline blends for spark-ignition engines, covering fuel properties, blending ratios, combustion behavior, engine performance, regulated and unregulated emissions, life-cycle impacts, and application prospects. The literature shows that methanol addition can enhance knock resistance, promote oxygenated combustion, reduce soot-forming tendency, and support higher compression ratios, optimized ignition timing, and lean-burn operation. However, its lower energy density increases fuel consumption, while water affinity, phase separation, cold-start difficulty, corrosion, and material compatibility remain key barriers. Emission responses are strongly condition-dependent. CO and particulate emissions are often reduced, whereas HC and NO_x vary with operating condition, mixture preparation, injection strategy, and after-treatment performance. Formaldehyde, unburned methanol, and cold-start oxygenated emissions require further attention. Life-cycle benefits depend mainly on methanol production pathways. Low-level blends are more suitable for near-term use in existing engines, while higher blends require optimized engines, compatible fuel systems, green methanol supply, infrastructure readiness, and cost reduction.

Keywords

methanol-gasoline blends / spark-ignition engines / alternative fuels / methanol blending ratio / combustion behavior / exhaust emissions

References

[1] Srikrishnan G, Shenbagamuthuraman V, Agbulut Ü, et al. (2024) Alcohol fuels in SI engines: A comprehensive state-of-the-art review on combustion, performance, and environmental impacts. J Therm Anal Calorim 149: 12141-12203. https://doi.org/10.1007/s10973-024-13544-3

[2] Verhelst S, Turner JWG, Sileghem L, et al. (2019) Methanol as a fuel for internal combustion engines. Prog Energy Combust Sci 70: 43-88. https://doi.org/10.1016/j.pecs.2018.10.001

[3] Agarwal AK, Kumar V, Singh AP (2026) Challenges and prospects of primary alcohols as global transport fuels. Fuel 414: 138177. https://doi.org/10.1016/j.fuel.2025.138177

[4] Wouters C, Burkardt P, Steeger F, et al. (2023) Comprehensive assessment of methanol as an alternative fuel for spark-ignition engines. Fuel 340: 127627. https://doi.org/10.1016/j.fuel.2023.127627

[5] Wang CM, Li YF, Xu CS, et al. (2019) Methanol as an octane booster for gasoline fuels. Fuel 248: 76-84. https://doi.org/10.1016/j.fuel.2019.02.128

[6] Ho CS, Peng JF, Yun U, et al. (2022) Impacts of methanol fuel on vehicular emissions: A review. Front Environ Sci Eng 16: 121. https://doi.org/10.1007/s11783-022-1553-4

[7] Yu H, Su Y, Shen B, et al. (2024) Effect of direct methanol injection based on low-flow injector on knock of gasoline engine under heavy load condition. Fuel 357: 129899. https://doi.org/10.1016/j.fuel.2023.129899

[8] Kassem MGA, Ahmed AMM, Abdel-Rahman HH, et al. (2019) Use of Span 80 and Tween 80 for blending gasoline and alcohol in spark ignition engines. Energy Rep 5: 221-230. https://doi.org/10.1016/j.egyr.2019.01.009

[9] Shirazi SA, Abdollahipoor B, Martinson J, et al. (2019) Effects of dual-alcohol gasoline blends on physiochemical properties and volatility behavior. Fuel 252: 542-552. https://doi.org/10.1016/j.fuel.2019.04.105

[10] Liu RB, Cui Q, Li HY, et al. (2025) Evaluating the influence of the compression ratio on the combustion process using methanol, gasoline, and methanol-gasoline blends. Energy Rep 14: 1645-1660. https://doi.org/10.1016/j.egyr.2025.08.003

[11] Boggavarapu P, Ashwin BM, Athreya VA, et al. (2025) Performance and emission characteristics of methanol and methanol-blended gasoline fuels in a high compression ratio SI engine. Appl Therm Eng 281: 128703. https://doi.org/10.1016/j.applthermaleng.2025.128703

[12] Esposito S, Malfi E, De Felice M, et al. (2025) Methanol fuelling of a spark-ignition engine: Experiments and 0D/1D predictive modelling for combustion, performance, and emissions. Fuel 393: 134657. https://doi.org/10.1016/j.fuel.2025.134657

[13] Prasad BSN, Kumar GN (2023) Influence of ignition timing on performance and emission characteristics of an SI engine fueled with equi-volume blend of methanol and gasoline. Energy Sources Part A 45: 4652-4666. https://doi.org/10.1080/15567036.2019.1670292

[14] Zhang MM, Cao JB (2024) Effects of lean burn on combustion and emissions of a DISI engine fueled with methanol-gasoline blends. Energies 17: 4023. https://doi.org/10.3390/en17164023

[15] Zhang MM, Cao JB (2024) Comparative study on combustion and emission characteristics of methanol/gasoline blend fueled DISI engine under different stratified lean burn modes. Fuel Process Technol 266: 108160. https://doi.org/10.1016/j.fuproc.2024.108160

[16] Zhang MM, Cao JB (2025) Effects of two-stage injection on combustion and particulate emissions of a direct injection spark-ignition engine fueled with methanol-gasoline blends. Energies 18: 415. https://doi.org/10.3390/en18020415

[17] Sharma N, Agarwal AK (2022) Microscopic spray characteristics of ethanol and methanol blended gasoline in a direct injection spark ignition engine. Int J Engine Res 23: 482-496. https://doi.org/10.1177/1468087420987763

[18] Feng S, Hong W, Li XP, et al. (2020) The influence of DISI engine control parameters and M15 fuel on regulated and particulate emissions under light-load. Fuel 276: 118024. https://doi.org/10.1016/j.fuel.2020.118024

[19] Yu J, Zhou F, Fu J, et al. (2024) Research on the influence of injection strategies on the in-cylinder combustion process and emissions of methanol. Biomass Bioenergy 188: 107340. https://doi.org/10.1016/j.biombioe.2024.107340

[20] Kalwar A, Singh RK, Gupta A, et al. (2023) Particulates, unregulated and regulated emissions and catalytic converter efficiency evaluation of methanol (M15) fuelled BS-VI compliant light-duty spark-ignition engine. Sci Total Environ 902: 166047. https://doi.org/10.1016/j.scitotenv.2023.166047

[21] Singh AP, Sonawane U, Agarwal AK (2022) Methanol/Ethanol/Butanol-Gasoline blends use in transportation engine-Part 2: Composition, morphology, and characteristics of particulates. J Energy Resour Technol 144: 101901. https://doi.org/10.1115/1.4053986

[22] Zhang Z, Wen MS, Cui YQ, et al. (2022) Effects of methanol application on carbon emissions and pollutant emissions using a passenger vehicle. Processes 10: 525. https://doi.org/10.3390/pr10030525

[23] Sarıkoç S (2021) Effect of H₂ addition to methanol-gasoline blend on an SI engine at various lambda values and engine loads: A case of performance, combustion, and emission characteristics. Fuel 297: 120732. https://doi.org/10.1016/j.fuel.2021.120732

[24] Duan XB, Chu XH, Wang RM, et al. (2025) The performance and emissions characteristics of the gasoline spark ignition engine fuelled with green and renewable methanol and hydrogen. Renewable Energy 240: 122184. https://doi.org/10.1016/j.renene.2024.122184

[25] Ahmed E, Usman M, Anwar S, et al. (2021) Application of ANN to predict performance and emissions of SI engine using gasoline-methanol blends. Sci Prog 104: 00368504211002345. https://doi.org/10.1177/00368504211002345

[26] Sharma N, Patel C, Tiwari N, et al. (2019) Experimental investigations of noise and vibration characteristics of gasoline-methanol blend fuelled gasoline direct injection engine and their relationship with combustion characteristics. Appl Therm Eng 158: 113754. https://doi.org/10.1016/j.applthermaleng.2019.113754

[27] Javanshayani F, Shamekhi AH (2025) Modern gasoline direct-injection engines: Key challenges and mitigation pathways: A critical review. Int J Engine Res 26: 325-338. https://doi.org/10.1177/14680874251382740

[28] Bharath BK, Selvan VAM (2021) Influence of higher alcohol additives in methanol-gasoline blends on the performance and emissions of an unmodified automotive SI engine: A review. Arab J Sci Eng 46: 7057-7085. https://doi.org/10.1007/s13369-021-05408-x

[29] Gassoumi M, Boutar Z, Shah RMRA, et al. (2023) Methanol as a fuel additive: Effect on the performance and emissions of a gasoline engine. Energy Sources Part A 45: 9485-9497. https://doi.org/10.1080/15567036.2023.2240741

[30] Topgül T, Cınar C, Ozdemir O (2021) The variations of the exhaust emissions at low ambient temperature for E10 and M10 fueled SI engine. J Therm Sci Technol 41: 227-237. https://doi.org/10.47480/isibted.1025931

[31] Cesur I, Uysal F (2024) Experimental investigation and artificial neural network-based modelling of thermal barrier engine performance and exhaust emissions for methanol-gasoline blends. Energy 291: 130393. https://doi.org/10.1016/j.energy.2024.130393

[32] Farooq MS, Baig A, Wei Y, et al. (2024) Comprehensive review on technical developments of methanol-fuel-based spark ignition engines to improve the performance, combustion, and emissions. J Energy Resour Technol 146: 070801. https://doi.org/10.1115/1.4065249

[33] Wouters C, Burkardt P, Pischinger S (2022) Limits of compression ratio in spark-ignition combustion with methanol. Int J Engine Res 23: 793-803. https://doi.org/10.1177/14680874211043390

[34] Agarwal A, Yadav O, Valera H (2024) Methanol (M85) port fuel-injected spark ignition motorcycle engine development-Part 1: Combustion optimization for efficiency improvement and emission reduction. SAE Int J Engines 17: 321-340. https://doi.org/10.4271/03-17-03-0018

[35] Singh H, Li C, Cheng P, et al. (2022) A critical review of technologies, costs, and projects for production of carbon-neutral liquid e-fuels from hydrogen and captured CO₂. Energy Adv 1: 580. https://doi.org/10.1039/D2YA00173J

[36] Di Iorio S, Catapano F, Magno A, et al. (2023) The potential of ethanol/methanol blends as renewable fuels for DI SI engines. Energies 16: 2791. https://doi.org/10.3390/en16062791

[37] Mokhtar, Sumarsono DA, Agama AA, et al. (2025) Performance, emissions, and combustion analysis of gasoline-ethanol-methanol blends in a spark-ignition engine. Results Eng 26: 105264. https://doi.org/10.1016/j.rineng.2025.105264

[38] Martin A, O’Malley J (2021) Compatibility of methanol fuel blends with gasoline vehicles and engines in Indonesia. ICCT report. Available from: https://theicct.org/wp-content/uploads/2021/12/Methanol-Indonesia-ENG-dec21.pdf.

[39] Kumar TS, Ashok B (2023) Material compatibility of SI engine components towards corrosive effects on methanol-gasoline blends for flex fuel applications. Mater Chem Phys 296: 127344. https://doi.org/10.1016/j.matchemphys.2023.127344

[40] Nuthan Prasad BS, Pandey JK, Kumar GN (2020) Impact of changing compression ratio on engine characteristics of an SI engine fueled with equi-volume blend of methanol and gasoline. Energy 191: 116605. https://doi.org/10.1016/j.energy.2019.116605

[41] Dobberkau M, Werner R, Atzler F (2024) Methanol, the ICE green maker. Chem Ing Tech 96: 1196-1202. https://doi.org/10.1002/cite.202400021

[42] Chandra K, Lakhsminarayanan PA, Agarwal AK (2025) Feasibility of methanol-gasoline blends in a production grade spark ignited carbureted genset engine: Particulate characterization and soot morphology. Fuel 389: 134461. https://doi.org/10.1016/j.fuel.2025.134461

[43] Fioroni GM, Christensen E, Fouts L, et al. (2019) Heat of vaporization and species evolution during gasoline evaporation measured by DSC/TGA/MS for blends of C1 to C4 alcohols in commercial gasoline blendstocks. International Powertrains, Fuels & Lubricants Meeting, San Antonio, Texas, United States. https://doi.org/10.4271/2019-01-0014

[44] Ailaboina A, Saha K (2023) Modeling the spray characteristics of blended fuels for gasoline direct injection applications. Int J Green Energy 20: 1326-1341. https://doi.org/10.1080/15435075.2022.2057801

[45] Wang Q, Zhang C, Jia M, et al. (2026) Material compatibility of methanol fuel with non-metallic components in engine fuel systems. Ind Eng Chem Res 65: 3188-3200. https://doi.org/10.1021/acs.iecr.5c03249

[46] Murad SHM, Camm J, Davy M, et al. (2016) Spray behaviour and particulate matter emissions with M15 methanol/gasoline blends in a GDI engine. SAE 2016 World Congress and Exhibition, Detroit, Michigan, United States. https://doi.org/10.4271/2016-01-0991

[47] Gassoumi M, Hamdi F, Boutar Z, et al. (2025) Performance and emissions assessment of a spark-ignition engine fueled with ethanol-, methanol- and acetone-gasoline blends. J Therm Eng 11: 1064-1074. https://doi.org/10.14744/thermal.0000964

[48] Agarwal A, Yadav O, Valera H (2024) Methanol (M85) port-fuel-injected spark ignition motorcycle engine development-Part 2: Dynamic performance, transient emissions, and catalytic converter effectiveness. SAE Int J Engines 17: 341-353. https://doi.org/10.4271/03-17-03-0019

[49] Chandra K, Lakhsminarayanan PA, Agarwal AK (2025) Feasibility of methanol-gasoline blends in a production grade spark ignited carbureted genset engine-Part 1: Engine performance, combustion and emission characteristics. ASME Open J Eng 4: 041014. https://doi.org/10.1115/1.4068675

[50] Ma R, Feng H, Zhang S, et al. (2024) Study on the effect of low carbon alcohol gasoline stratified injection strategy on engine knock combustion under lean burn conditions. Energy 313: 133716. https://doi.org/10.1016/j.energy.2024.133716

[51] Son J, Bae G, Moon S (2025) Injection rate and flow characteristics of gasoline-methanol blended fuels from GDI injector according to methanol blending ratio. Int Commun Heat Mass Transf 169: 109545. https://doi.org/10.1016/j.icheatmasstransfer.2025.109545

[52] Chakradhar M, Ramadhas A, Shanti P, et al. (2023) Material compatibility of elastomers and plastics in gasoline-ethanol-methanol blends. WCX SAE World Congress Experience, Detroit, Michigan, United States. https://doi.org/10.4271/2023-01-0336

[53] Abdellatief TMM, Ershov MA, Savelenko VD, et al. (2023) Advanced progress and prospects for producing high-octane gasoline fuel toward market development: State-of-the-art and outlook. Energy Fuels 37: 18266-18290. https://doi.org/10.1021/acs.energyfuels.3c02541

[54] Bulbul NE, Çakmak A (2025) The effectiveness of iso-alcohols in reducing vapor pressure and enhancing fuel properties of ethanol-gasoline mixtures. Int J Automot Eng Technol 14: 1-10. https://doi.org/10.18245/ijaet.1591917

[55] Geng Z, Ding C, Hu J, et al. (2025) Revealing a new mechanism of stable intersolubility of methanol-n-heptane blended fuel assisted by co-solvents at the microscopic molecular level: Insights and validation from quantum chemical simulation. J Mol Liq 417: 126626. https://doi.org/10.1016/j.molliq.2024.126626

[56] Shenbagamuthuraman V, Patel A, Vemuluri S, et al. (2022) Progress on compatibility issues of alcohols on automotive materials: Kinetics, challenges and future prospects-A comprehensive review. Process Saf Environ Prot 162: 463-493. https://doi.org/10.1016/j.psep.2022.04.022

[57] Müller M, Mishra RK, Šleger V, et al. (2024) Elastomer-based sealing o-rings and their compatibility with methanol, ethanol, and hydrotreated vegetable oil for fueling internal combustion engines. Materials 17: 430. https://doi.org/10.3390/ma17020430

[58] Boggavarapu P, Mallikarjun AB, Mendu H, et al. (2025) Performance and emission measurement of spark ignition engines operating with 100% methanol fuel. Heat Transf Eng 46: 839-851. https://doi.org/10.1080/01457632.2024.2347177

[59] Turner JWG, Lewis AGJ, Akehurst S, et al. (2018) Alcohol fuels for spark-ignition engines: Performance, efficiency and emission effects at mid to high blend rates for binary mixtures and pure components. Proc Inst Mech Eng Part D J Automob Eng 232: 36-56. https://doi.org/10.1177/0954407017752832

[60] Gong C, Yi L, Zhang Z, et al. (2020) Assessment of ultra-lean burn characteristics for a stratified-charge direct-injection spark-ignition methanol engine under different high compression ratios. Appl Energy 261: 114478. https://doi.org/10.1016/j.apenergy.2019.114478

[61] Ismael MA, El-Adawy M, Khedr AM, et al. (2026) Comparative experimental assessment of methanol, ethanol, and butanol fuels in a spark-ignition engine: Combustion, performance, and emissions. J Energy Resour Technol Part A 2: 042301. https://doi.org/10.1115/1.4071226

[62] Feng H, Xiao S, Nan Z, et al. (2021) Thermodynamic analysis of using ethanol-methanol-gasoline blends in a turbocharged, spark-ignition engine. J Energy Resour Technol 143: 120903. https://doi.org/10.1115/1.4050783

[63] Fatouraie M, Frommherz M, Mosburger M, et al. (2018) Investigation of the impact of fuel properties on particulate number emission of a modern gasoline direct injection engine. WCX World Congress Experience, Detroit, Michigan, United States. https://doi.org/10.4271/2018-01-0358

[64] Gong C, Huang W, Liu J, et al. (2018) Detection and analysis of formaldehyde and unburned methanol emissions from a direct-injection spark-ignition methanol engine. Fuel 221: 188-195. https://doi.org/10.1016/j.fuel.2018.02.115

[65] Yang S, Feng J, Sun P, et al. (2023) Combustion and emissions characteristics of methanol/gasoline CISI engines under different injection modes. Fuel 333: 126506. https://doi.org/10.1016/j.fuel.2022.126506

[66] Xia C, Zhao T, Fang J, et al. (2022) Experimental study of stratified lean burn characteristics on a dual injection gasoline engine. Front Energy 16: 900-915. https://doi.org/10.1007/s11708-021-0812-6

[67] Ahamad J, Kumar P, Dhar A (2024) Effect of multi-injection strategy on characteristics of methanol-fueled direct injection spark ignition engine. Phys Fluids 36: 047107. https://doi.org/10.1063/5.0198169

[68] Malik MAI, Usman M, Akhtar M, et al. (2023) Response surface methodology application on lubricant oil degradation, performance, and emissions in SI engine: A novel optimization of alcoholic fuel blends. Sci Prog 106: 00368504221148342. https://doi.org/10.1177/00368504221148342

[69] Örs İ, Yelbey S, Gülcan HE, et al. (2023) Evaluation of detailed combustion, energy and exergy analysis on ethanol-gasoline and methanol-gasoline blends of a spark ignition engine. Fuel 354: 129340. https://doi.org/10.1016/j.fuel.2023.129340

[70] Liu X, Shakeel MR, Raman V, et al. (2025) Assessment of methanol combustion engines in spark ignition, spark-, and glow plug-assisted compression ignition modes. Appl Therm Eng 280: 128538. https://doi.org/10.1016/j.applthermaleng.2025.128538

[71] Feng H, Lai K, Zheng Z, et al. (2024) Effects of methanol direct injection and high compression ratio on improving the performances of a spark-ignition passenger car engine. Fuel 357: 130052. https://doi.org/10.1016/j.fuel.2023.130052

[72] Elfasakhany A (2015) Investigations on the effects of ethanol-methanol-gasoline blends in a spark-ignition engine: Performance and emissions analysis. Eng Sci Technol Int J 18: 713-719. https://doi.org/10.1016/j.jestch.2015.05.003

[73] Malik MAI, Usman M, Hayat N, et al. (2021) Experimental evaluation of methanol-gasoline fuel blend on performance, emissions and lubricant oil deterioration in SI engine. Adv Mech Eng 13: 16878140211025213. https://doi.org/10.1177/16878140211025213

[74] Celik MB (2008) Experimental determination of suitable ethanol-gasoline blend rate at high compression ratio for gasoline engine. Appl Therm Eng 28: 396-404. https://doi.org/10.1016/j.applthermaleng.2007.10.028

[75] Balki MK, Sayin C (2014) The effect of compression ratio on the performance, emissions and combustion of an SI engine fueled with pure ethanol, methanol and unleaded gasoline. Energy 71: 194-201. https://doi.org/10.1016/j.energy.2014.04.074

[76] Akbiyik T, Kahraman N, Taner T (2023) Energy and exergy analysis with emissions evaluation of a gasoline engine using different fuels. Fuel 345: 128189. https://doi.org/10.1016/j.fuel.2023.128189

[77] Sathish Kumar T, Ashok B (2024) Development of combustion control map for flex fuel operation in methanol powered direct injection SI engine. Energy 288: 129695. https://doi.org/10.1016/j.energy.2023.129695

[78] Cesur I (2022) Investigation of the effects of water injection into an SI engine running on M15 methanol fuel on engine performance and exhaust emissions. Energy 261: 125203. https://doi.org/10.1016/j.energy.2022.125203

[79] Choi J, Lim O (2025) An investigation of ultra-lean combustion characteristics of methanol direct injection in a rapid compression expansion machine with various coil spark ignition strategies. Fuel 389: 134612. https://doi.org/10.1016/j.fuel.2025.134612

[80] Wei H, Zhang Z, Zhang X, et al. (2025) Overview for methanol and formaldehyde unregulated emissions of methanol fueled engines. J Energy Inst 120: 102089. https://doi.org/10.1016/j.joei.2025.102089

[81] Kumar TS, Ashok B (2021) Critical review on combustion phenomena of low carbon alcohols in SI engine with its challenges and future directions. Renewable Sustainable Energy Rev 152: 111702. https://doi.org/10.1016/j.rser.2021.111702

[82] Miganakallu N, Yang Z, Rogóż R, et al. (2020) Effect of water-methanol blends on engine performance at borderline knock conditions in gasoline direct injection engines. Appl Energy 264: 114750. https://doi.org/10.1016/j.apenergy.2020.114750

[83] Duan W, Geng X, Zhang S, et al. (2025) Lean combustion effects on a high-compression methanol SI engine derived from a turbocharged miller cycle gasoline engine. Adv Mech Eng 17: 16878132251383368. https://doi.org/10.1177/16878132251383368

[84] Chandra K, Lakhsminarayanan PA, Agarwal AK (2025) Feasibility of methanol-gasoline blends in a production grade spark-ignited carbureted genset engine-Part 2: Unregulated emission characteristics. ASME Open J Eng 4: 041015. https://doi.org/10.1115/1.4068676

[85] Kalwar A, Singh RK, Gupta A, et al. (2023) Combustion and performance evaluation of methanol (M15)-Fueled BS-VI compliant light-duty spark-ignition engine. ASME Open J Eng 2: 021050. https://doi.org/10.1115/1.4063343

[86] Marwaha A, Subramanian KA (2025) Control of regulated and unregulated emissions of an automotive spark ignition engine with alternative fuels (methanol, ethanol and hydrogen). Meas Energy 5: 100039. https://doi.org/10.1016/j.meaene.2025.100039

[87] Örs İ, Gülcan HE, Sayın Kul B, et al. (2022) Evaluation of the effects of methanol and ethanol additions on performance and emissions in a spark plug ignition engine fueled with gasoline. Int J Automot Sci Technol 6: 156-164. https://doi.org/10.30939/ijastech..1081731

[88] Zhou Y, Xie F, Zhang B, et al. (2025) Research on combustion cycle-by-cycle variations under high load in SACI mode and application potential of i-EGR coupling air dilution when fueled with methanol and gasoline. Int J Engine Res 26: 2. https://doi.org/10.1177/14680874241274560

[89] Yuan B, Zhang X, Cao J, et al. (2025) Investigation on the development law of methanol spray impinging on intake valve during port fuel injection. Energy 320: 135250. https://doi.org/10.1016/j.energy.2025.135250

[90] Li X, Zhen X, Wang Y, et al. (2022) Numerical comparative study on performance and emissions characteristics fueled with methanol, ethanol and methane in high compression spark ignition engine. Energy 254: 124374. https://doi.org/10.1016/j.energy.2022.124374

[91] Gong C, Liu J, Peng L, et al. (2017) Numerical study of effect of injection and ignition timings on combustion and unregulated emissions of DISI methanol engine during cold start. Renewable Energy 112: 457-465. https://doi.org/10.1016/j.renene.2017.05.055

[92] Han T, Singh R, Lavoie G, et al. (2020) Multiple injection for improving knock, gaseous and particulate matter emissions in direct injection SI engines. Appl Energy 262: 114578. https://doi.org/10.1016/j.apenergy.2020.114578

[93] Shen B, Su Y, Yu H, et al. (2023) Experimental study on the effect of injection strategies on the combustion and emissions characteristic of gasoline/methanol dual-fuel turbocharged engine under high load. Energy 282: 128925. https://doi.org/10.1016/j.energy.2023.128925

[94] Wang J, Tian H, Zhang R, et al. (2023) Experimental investigation on the effects of direct injection timing on the combustion, performance and emission characteristics of methanol/gasoline dual-fuel spark turbocharged ignition (DFSI) engine with different injection pressures under high load. Energies 16: 7921. https://doi.org/10.3390/en16247921

[95] Farooq MS, Baig A, Wei Y, et al. (2025) A concise review of developments to overcome the cold start problems by analyzing combustion and emissions of methanol-based-fueled spark ignition engines. Int J Hydrogen Energy 99: 852-871. https://doi.org/10.1016/j.ijhydene.2024.12.263

[96] Gong C, Liu Z, Su H, et al. (2019) Effect of injection strategy on cold start firing, combustion and emissions of a LPG/methanol dual-fuel spark-ignition engine. Energy 178: 126-133. https://doi.org/10.1016/j.energy.2019.04.145

[97] Wang MQ (1999) GREET 1.5-Transportation Fuel-Cycle Model. Volume 1: Methodology, development, use, and results. Available from: https://rosap.ntl.bts.gov/view/dot/15284.

[98] Masum FH, Tan ECD, Kolodziej CP, et al. (2025) Life cycle assessment of methanol from fossil, biomass, and waste sources, and its use as a marine fuel in dual-fuel engines. Environ Sci Technol 59: 23239-23250. https://doi.org/10.1021/acs.est.5c08873

[99] Peng S, Tang Y, Tang J, et al. (2025) Techno-economic analysis and life cycle assessment of renewable methanol production from MSW integrated with oxy-fuel combustion and solid oxide electrolysis cell. Int J Hydrogen Energy 99: 872-887. https://doi.org/10.1016/j.ijhydene.2024.12.232

[100] Badger N, Amini S (2025) Comparative life cycle assessment of various hydrogen pathways for cleaner methanol synthesis. J Clean Prod 533: 146993. https://doi.org/10.1016/j.jclepro.2025.146993

[101] Nemmour A, Inayat A, Janajreh I, et al. (2023) Green hydrogen-based E-fuels (E-methane, E-methanol, E-ammonia) to support clean energy transition: A literature review. Int J Hydrogen Energy 48: 29011-29033. https://doi.org/10.1016/j.ijhydene.2023.03.240

[102] Pérez-Fortes M, Schöneberger JC, Boulamanti A, et al. (2016) Methanol synthesis using captured CO₂ as raw material: Techno-economic and environmental assessment. Appl Energy 161: 718-732. https://doi.org/10.1016/j.apenergy.2015.07.067

[103] Pfennig M, Böttger D, Häckner B, et al. (2023) Global GIS-based potential analysis and cost assessment of Power-to-X fuels in 2050. Appl Energy 347: 121289. https://doi.org/10.1016/j.apenergy.2023.121289

[104] Alhyari M, Al-Salaymeh A, Irshidat M, et al. (2019) The impact of energy source on the life-cycle assessment of power-to-liquid fuels. J Ecol Eng 20: 239-244. https://doi.org/10.12911/22998993/104659

[105] Aramco, Methanol Institute. (2024) Accelerating the net-zero transition: Assessing potentials of e-fuels in China’s road transport. Available from: https://www.methanol.org/wp-content/uploads/2024/05/AramcoMI-Joint-Report-Final.pdf.

[106] Duan Q, Li T, Liu D, et al. (2024) Improving the lean burn performance of a high compression ratio methanol engine by multiple-injection. Appl Therm Eng 236: 121481. https://doi.org/10.1016/j.applthermaleng.2023.121481

[107] Badawy T, Panithasan MS, Turner JWG, et al. (2024) Performance and emissions evaluation of a multi-cylinder research engine fueled with ethanol, methanol, gasoline Euro-6, E85, and iso-stoichiometric ternary GEM mixtures operated at lean conditions. Fuel 363: 130962. https://doi.org/10.1016/j.fuel.2024.130962

[108] Zhao LF, Wang DF, Qi WQ (2020) Particulate matter emissions and performance of bio-butanol-methanol-gasoline blends coupled with air dilution in SI engines. J Aerosol Sci 145: 105546. https://doi.org/10.1016/j.jaerosci.2020.105546

[109] Ziyad F, Aman S, Alemayehu H, et al. (2026) Optimizing SI engine performance and emissions with gasoline-ethanol and gasoline-methanol blends. Clean Energy Sustainable 4: 10003. https://doi.org/10.70322/ces.2026.10003

[110] Fasihi M, Breyer C (2024) Global production potential of green methanol based on variable renewable electricity. Energy Environ Sci 17: 3503-3522. https://doi.org/10.1039/D3EE02951D

[111] Li P, Lin J, Yu Z, et al. (2024) Feasibility study of renewable e-methanol production: A substitution pathway from blue to green. iEnergy 3: 108-114. https://doi.org/10.23919/IEN.2024.0013

[112] De Felice G, Eichkorn S, Gallucci F, et al. (2025) Techno-economic analysis of plasma-assisted CO₂ hydrogenation to methanol: feasibility and the impact of electricity supply. EES Catal 3: 1327-1344. https://doi.org/10.1039/D5EY00130G

[113] Bozzini MM, Signorelli M, Moioli E, et al. (2025) Techno-economic-assessment of the methanol synthesis from captured CO₂ and modular nuclear power-based electrolysis. J CO₂ Util 101: 103186. https://doi.org/10.1016/j.jcou.2025.103186

[114] Zhang W, Wen C, Zhang X, et al. (2025) A review of green methanol production: technologies, economic evaluation, and carbon emission analysis. Energy Fuels 39: 18733-18750. https://doi.org/10.1021/acs.energyfuels.5c03278

[115] Khawaja R, Musa T, Challiwala MS, et al. (2025) Decarbonizing methanol synthesis via low-carbon hydrogen: Process simulation and techno-economic insights. Front Chem Eng 7: 1717905. https://doi.org/10.3389/fceng.2025.1717905

[116] Nunes LJR (2025) Renewable methanol as an agent for the decarbonization of maritime logistic systems: A review. Future Transp 5: 54. https://doi.org/10.3390/futuretransp5020054

[117] Ismail AM, Metwalli MMA, Alamoush AS (2025) Towards safe maritime decarbonization: Safety barriers of methanol fuel. Sustainability 17: 4896. https://doi.org/10.3390/su17114896

[118] Transportation Energy Institute (2024) E-fuels: Evaluating the viability of commercially deploying e-fuels in road transport. Available from: https://www.transportationenergy.org/research/reports/e-fuels-evaluating-the-viability-of-commercially-deploying-e-fuels-in-road-transport/.

[119] BloombergNEF, Climate Technology Coalition (2024) Scaling up hydrogen: The case for low-carbon methanol. Available from: https://assets.bbhub.io/media/sites/25/2024/06/BNEF-Methanol-Report_to-publish.pdf.

[120] U.S. Energy Information Administration (2026) Gasoline and diesel fuel update. Available from: https://www.eia.gov/petroleum/gasdiesel.

[121] Methanex Corporation (2026) Methanol pricing: Regional posted contract prices. Available from: https://www.methanex.com/our-products/about-methanol/pricing.

[122] Alternative Fuels Data Center (2024) Fuel properties comparison chart. U.S. Department of Energy. Available from: https://afdc.energy.gov/files/u/publication/fuel_comparison_chart.pdf.

[123] Mission Green Fuels (2024) Roadmap for green fuels in transport and industry. Available from: https://missiongreenfuels.dk/roadmap-for-green-fuels/.

[124] Zhang Y, Su Y, Li X, et al. (2025) Study and prediction on macroscopic characteristics of free spray of typical alcohol fuels through experimentation and the artificial neural network. Energy 316: 134610. https://doi.org/10.1016/j.energy.2025.134610

[125] Xi D, Chen S, Xiao G, et al. (2025) Comprehensive performance improvement of methanol/diesel dual-fuel engines using multi-physics field coupling simulation and surrogate-assisted many-objective optimization. Energy 340: 139185. https://doi.org/10.1016/j.energy.2025.139185