Potential impacts of ammonia/hydrogen on engine lubricants: A review

Abstract

As intrinsically carbon-free molecules, ammonia and hydrogen are considered as fuels for internal combustion engines, mainly for long-distance or off-road applications. These alternative fuels have different combustion characteristics, reactivity, and exhaust gas compositions compared to conventional fuels, raising questions about the suitability of lubricants in engines operating with them. The impact of ammonia, hydrogen, and their blends on lubricants in internal combustion engines is a relatively new topic, with few reference studies available. However, degradation processes of lubricants have been studied in the context of hydrocarbon fuels, and in compressors using ammonia as a refrigerant, for example. This work presents a review of the literature on engine oil degradation phenomena in relation to ammonia and hydrogen combustion characteristics. In particular, it highlights the current state of knowledge regarding compatibility with unburnt gases, elevated nitrogen oxide levels, and water. Additionally, it summarizes the latest insights into the contribution of lubricants to pollutant emissions.

Graphical abstract

Keywords

lubricant / engine oil / hydrogen engine / ammonia engine

References

[1] IEA . Transport Sector Overview 2022. 2025-6-25, available at website of IEA, ,

[2] Citepa . Gaz à effet de serre et polluants atmosphériques - Bilan des émissions en France de 1990 à 2021. Rapport national d’inventaire format secten, 2022,

[3] IntergovernmentalPanel on Climate Change (IPCC). Transport. In: Climate Change 2022—Mitigation of Climate Change: Working Group III Contribution to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge: Cambridge University Press, 2023, 1049–1160

[4] Ma H, Sun Z, Xue Z. . A systemic review of hydrogen supply chain in energy transition. Frontiers in Energy, 2023, 17(1): 102–122

[5] Valera-Medina A, Amer-Hatem F, Azad A K. . Review on ammonia as a potential fuel: From synthesis to economics. Energy & Fuels, 2021, 35(9): 6964–7029

[6] Lhuillier C, Brequigny P, Contino F. . Experimental study on ammonia/hydrogen/air combustion in spark ignition engine conditions. Fuel, 2020, 269: 117448

[7] Mounaïm-Rousselle C, Bréquigny P, Medina A V. . Engines and Fuels for Future Transport. Singapore: Springer Singapore, 2022, 257–279

[8] National Minerals Information Center. Nitrogen Statistics and Information. 2025-6-11, available at website of USGS, ,

[9] International Energy Agency (IEA). Ammonia Technology Roadmap. 2025-6-11, available at website of IEA, ,

[10] Cao J, Hu Y, Zheng Y. . Recent advances and challenges of nitrogen/nitrate electro catalytic reduction to ammonia synthesis. Frontiers in Energy, 2024, 18(2): 128–140

[11] Verhelst S, Wallner T. Hydrogen-fueled internal combustion engines. Progress in Energy and Combustion Science, 2009, 35(6): 490–527

[12] Wang B, Yang C, Wang H. . Study on injection strategy of ammonia/hydrogen dual fuel engine under different compression ratios. Fuel, 2023, 334: 126666

[13] Rasberger M. Chemistry and Technology of Lubricants. Dordrecht: Springer, 1997, 98–143

[14] Agocs A, Rappo M, Obrecht N. . The impact of ammonia fuel on marine engine lubrication: An artificial lubricant ageing approach. Lubricants, 2023, 11(4): 165

[15] Singh S, Bathla V K, Mathai R. . Development of dedicated lubricant for hydrogen fuelled spark ignition engine. SAE Technical Paper 2019-28-2511, 2019,

[16] Dörr N, Agocs A, Besser C. . Engine oils in the field: A comprehensive chemical assessment of engine oil degradation in a passenger car. Tribology Letters, 2019, 67(3): 68

[17] Takahashi H, Kaimai T. New type lubricant for ammonia refrigerating systems. In: International Refrigeration and Air Conditioning Conference, 1996,

[18] Mercier A, Mounaïm-Rousselle C, Brequigny P. . Improvement of SI engine combustion with ammonia as fuel: Effect of ammonia dissociation prior to combustion. Fuel Communications, 2022, 11: 100058

[19] Dupuy A, Brequigny P, Schmid A. . Experimental study of RCCI engine – Ammonia combustion with diesel pilot injection. The Journal of Ammonia Energy, 2023, 1(1): 11–20

[20] Mounaïm-Rousselle C, Bréquigny P, Dumand C. . Operating limits for ammonia fuel spark-ignition engine. Energies, 2021, 14(14): 4141

[21] Johnson M D, Korcek S. Effects of NO_x on liquid phase oxidation and inhibition at elevated temperatures. Lubrication Science, 1991, 3(2): 95–118

[22] Pochopien B A. Interactions of antioxidants with NO_x at elevated temperatures. Dissertation for the Doctoral Degree. York: University of York, 2012,

[23] Coultas D R. The role of NO_x in engine lubricant oxidation. SAE International Journal of Advances and Current Practices in Mobility, 2020, 2(5): 3009–3016

[24] ASTM International. Standard Test Method for Condition Monitoring of Nitration in In-Service Petroleum and Hydrocarbon-Based Lubricants by Trend Analysis Using Fourier Transform Infrared (FT-IR) Spectrometry. 22nd ed, 2022,

[25] Boero A, Mercier A, Mounaïm-Rousselle C. . Environmental assessment of road transport fueled by ammonia from a life cycle perspective. Journal of Cleaner Production, 2023, 390: 136150

[26] Feja S, Hanzelmann C, Zuber S M. PT and viscosity measurements of high-temperature ammonia heat pump lubricants. International Journal of Refrigeration, 2018, 88: 221–228

[27] Short G D. Assessment of lubricants for ammonia and carbon dioxide refrigeration systems. 2025-6-11, available at website of IIAR, ,

[28] Obrecht N, Griffaton B, Rappo M. Lubricant performance and reliability of ammonia fueled internal combustion engines. SAE Technical Paper 2023-32-0104, 2023,

[29] Cen H, Morina A, Neville A. Effect of ageing on lubricants’ physical and chemical properties and tribological performance. Industrial Lubrication and Tribology, 2019, 71(1): 48–53

[30] FluidLife. The impact of water contamination on lubricants. 2019

[31] Miller A L, Stipe C B, Habjan M C. . Role of lubrication oil in particulate emissions from a hydrogen-powered internal combustion engine. Environmental Science & Technology, 2007, 41(19): 6828–6835

[32] Duchesne P. Physical chemistry and formulation of lubricating oils and additives. IFP School Course Material, 2024,

[33] Delprete C, Razavykia A. Piston dynamics, lubrication and tribological performance evaluation: A review. International Journal of Engine Research, 2020, 21(5): 725–741

[34] Ayel J. Lubrifiants - Propriétés et caractéristiques, Frottement, usure et lubrification. Techniques de l’ingénieur, 1996,

[35] Berthome V, Chalet D, Hetet J F. Consequence of blowby flow and idling time on oil consumption and particulate emissions in gasoline engine. Energies, 2022, 15(22): 8772

[36] Yilmaz E, Tian T, Wong V W. . The contribution of different oil consumption sources to total oil consumption in a spark ignition engine. SAE Technical Paper 2004-01-2909, 2004,

[37] Jang J C S. Effects of skirt profiles on the piston secondary movements by the lubrication behaviors. International Journal of Automotive Technology, 2003, 5: 23–31

[38] Wang Y, Liang X, Shu G. . Effects of an anti-wear oil additive on the size distribution, morphology, and nanostructure of diesel exhaust particles. Tribology International, 2015, 92: 379–386

[39] Karjalainen P, Ntziachristos L, Murtonen T. . Heavy duty diesel exhaust particles during engine motoring formed by lube oil consumption. Environmental Science & Technology, 2016, 50(22): 12504–12511

[40] API . API base oil interchangeability guidelines for passenger car motor oils and diesel engine oils. 2025-6-11, available at website of API, ,

[41] Minami I. Molecular science of lubricant additives. Applied Sciences, 2017, 7(5): 445

[42] Ayel J. Lubrifiants - Additifs à action chimique, Frottement, usure et lubrification. Techniques de l’ingénieur, 2001,

[43] Ayel J. Lubrifiants - Additifs à action physique ou physiologique, Frottement, usure et lubrification. Techniques de l’ingénieur, 2002,

[44] Bender J W. Friction modifiers. In: Wang Q J, Chung Y W, eds. Encyclopedia of Tribology. Boston: Springer, 2013, 1355–1359

[45] Tang H Z, Jao T C. Detergents. In: Wang Q J, Chung Y W, eds. Encyclopedia of Tribology. Boston: Springer, 2013, 720–726

[46] Tang H Z, Jao T C. Dispersant additives. In: Wang Q J, Chung Y W, eds. Encyclopedia of Tribology, Boston: Springer, 2013, 771–781

[47] Secrétaire d’Etat à la Mer, Article 213-614 – Oxydes de Soufre et particules. in : Arrêté du 23 novembre 1987 relatif à la sécurité des navires et à la prévention de la pollution. , ,

[48] Xin G, Ji C, Wang S. . Effect of different volume fractions of ammonia on the combustion and emission characteristics of the hydrogen-fueled engine. International Journal of Hydrogen Energy, 2022, 47(36): 16297–16308

[49] Kobayashi H, Hayakawa A, Somarathne K K A. . Science and technology of ammonia combustion. Proceedings of the Combustion Institute, 2019, 37(1): 109–133

[50] Li J, Huang H, Kobayashi N. . Study on using hydrogen and ammonia as fuels: Combustion characteristics and NO_x formation. International Journal of Energy Research, 2014, 38(9): 1214–1223

[51] Law C K. Kwon O C. Effects of hydrocarbon substitution on atmospheric hydrogen–air flame propagation. International Journal of Hydrogen Energy, 2004, 29(8): 867–879

[52] Zhang R, Shu G, Zhao H. . A comparative study on NH₃/H₂ and NH₃/CH₃OH combustion and emission in an optical SI engine. Fuel, 2024, 369: 131731

[53] Hu X, Li J, Pan J. . On combustion and emission characteristics of ammonia/hydrogen engines: Emphasis on energy ratio and equivalence ratio. Fuel, 2024, 365: 131183

[54] Li J, Shu G, Wang L. . An experimental investigation on hydrogen jet ignition of ammonia: Emphasis on reactivity stratification. Proceedings of the Combustion Institute, 2024, 40(1–4): 105328

[55] Wang L, Mao X, Li J. . Role of hydrogen enrichment in ammonia forced ignition at elevated pressures. Combustion and Flame, 2025, 272: 113908

[56] SchindlbacherSTistaMGagerM. NEC Directive Status Report 2012. EEA Technical Report No 6/2013. 2013

[57] Glarborg P, Miller J A, Ruscic B. . Modeling nitrogen chemistry in combustion. Progress in Energy and Combustion Science, 2018, 67: 31–68

[58] Luo Q, Hu J B, Sun B. . Experimental investigation of combustion characteristics and NO_x emission of a turbocharged hydrogen internal combustion engine. International Journal of Hydrogen Energy, 2019, 44(11): 5573–5584

[59] De Soete G G. Overall reaction rates of NO and N₂ formation from fuel nitrogen. Symposium (International) on Combustion, 1975, 15: 1093–1102

[60] Sako N, Hayashi J, Sako T. . Nitrogen-origin-determination in NO_x formation under ammonia/methane/air co-combustion using a nitrogen-tagged reaction model. Combustion and Flame, 2024, 259: 113210

[61] Xiang P, Liu J, Zhao W. . Experimental investigation on gas emission characteristics of ammonia/diesel dual-fuel engine equipped with DOC + SCR aftertreatment. Fuel, 2024, 359: 130496

[62] Westlye F R, Ivarsson A, Schramm J. Experimental investigation of nitrogen based emissions from an ammonia fueled SI-engine. Fuel, 2013, 111: 239–247

[63] Rahinov I, Ditzian N, Goldman A. . NH₂ radical formation by ammonia pyrolysis in a temperature range of 800–1000 K. Applied Physics. B, Lasers and Optics, 2003, 77(5): 541–546

[64] Chatelain K. Oxidation stability of fuels in liquid phase. Dissertation for the Doctoral Degree. Paris: University of Paris-Saclay (ComUE), 2016,

[65] Venegas-Reynoso A, Giarracca-Mehl L, Lacoue-Negre M. . Identification of key molecular deatures in liquid phase autooxidation of hydrocarbons. Energy & Fuels, 2025, 39(2): 1192–1201

[66] Mathai R, Malhotra R K, Subramanian K A. . Comparative evaluation of performance, emission, lubricant and deposit characteristics of spark ignition engine fueled with CNG and 18% hydrogen-CNG. International Journal of Hydrogen Energy, 2012, 37(8): 6893–6900

[67] Slavchov R I, Salamanca M, Russo D. . The role of NO₂ and NO in the mechanism of hydrocarbon degradation leading to carbonaceous deposits in engines. Fuel, 2020, 267: 117218

[68] Spindt R S, Wolfe C L, Stevens D R. Nitrogen oxides, combustion, and engine deposits. Journal of the Air Pollution Control Association, 1956, 6(3): 127–133

[69] Hiraoka K, Matsunaga D, Kamino T. . Experimental and numerical analysis on combustion characteristics of ammonia and diesel dual fuel engine. SAE International Journal of Advances and Current Practices in Mobility, 2024, 6(3): 1441–1458

[70] Rousselle C, Brequigny P, Dupuy A. Impact of splitting n-dodecane pilot injection on ammonia RCCI engine. SAE Technical Paper 2023-24-0076, 2023,

[71] Valera-Medina A, Gutesa M, Xiao H. . Premixed ammonia/hydrogen swirl combustion under rich fuel conditions for gas turbines operation. International Journal of Hydrogen Energy, 2019, 44(16): 8615–8626

[72] Harris N. The degradation of lubricant and fuel due to nitrogen dioxide. Dissertation for the Doctoral Degree. York: University of York, 2016,

[73] Maxwell L R, Mosley V M. Molecular structure of nitrogen dioxide and nitric acid by electron diffraction. Journal of Chemical Physics, 1940, 8(9): 738–742

[74] Gray P. Bond dissociation energies in nitrites and nitro compounds and the reaction of free radicals with nitrogen dioxide. Transactions of the Faraday Society, 1955, 51: 1367

[75] Titov A I. The free radical mechanism of nitration. Tetrahedron, 1963, 19(4): 557–580

[76] Slavchov R I, Mosbach S, Kraft M. . An adsorption-precipitation model for the formation of injector external deposits in internal combustion engines. Applied Energy, 2018, 228: 1423–1438

[77] Besser C, Agocs A, Ristic A. . Implementation of nitration processes in artificial ageing for closer-to-reality simulation of engine oil degradation. Lubricants, 2022, 10(11): 298

[78] Huie R E. The reaction kinetics of NO₂. Toxicology, 1994, 89(3): 193–216

[79] De Barros B, Martin J M, Le Mogne T. . Mechanisms of MoS₂ formation by MoDTC in presence of ZnDTP: Effect of oxidative degradation. Wear, 2005, 258(11‒12): 1643–1650

[80] Fuller M L, Kasrai M, Bancroft G. . Solution decomposition of zinc dialkyl dithiophosphate and its effect on antiwear and thermal film formation studied by X-ray absorption spectroscopy. Tribology International, 1998, 31(10): 627–644

[81] Dörr N, Brenner J, Ristić A. . Correlation between engine oil degradation, tribochemistry, and tribological behavior with focus on ZDDP deterioration. Tribology Letters, 2019, 67(2): 62

[82] Ponjavic A, Lemaigre T, Southby M. . Influence of NO_x and air on the ageing behaviour of MoDTC. Tribology Letters, 2017, 65(2): 52

[83] Northrop W F. Modeling nitrogen species from ammonia reciprocating engine combustion in temperature-equivalence ratio space. Applications in Energy and Combustion Science, 2024, 17: 100245

[84] Liu S, Lin Z, Qi Y. . Combustion and emission characteristics of a gasoline/ammonia fueled SI engine and chemical kinetic analysis of NO_x emissions. Fuel, 2024, 367: 131516

[85] Johan K, Henrik C, Shenghui C. . Developing the MAN B&W dual fuel ammonia engine. CIMAC World Congress Technical Papers, 2023,

[86] Rik C, Li S, Marcel V. The role of marine lubricants in lowering the carbon intensity of maritime transport. CIMAC World Congress Technical Papers, 2023,

[87] Fluitec L D C, Livingstone G. Lubricant deposit characterization. 2023-3-9, available at website of slideshare, ,

[88] Testoil . What causes sludge in machinery. 2025-6-11, available at website of Testoil, ,

[89] Obrecht N, Griffaton B. Hydrogen internal combustion engine lubrication challenges and engine oil requirements. SIA 2022 Technical Paper, 2022,

[90] Chevron Marine Lubricants. What about water. 2023-3-1, available at website of chevronmarineproducts, ,

[91] Jeremy Wright. Water contamination of lube oils – How to detect and remove water in oil. Machinery Lubrication, 2008,

[92] Shishigin A A, Bel’ganovich V I. Change in engine oil quality due to water contamination. Chemistry and Technology of Fuels and Oils, 1976, 12(2): 147–150

[93] Apicella B, Catapano F, Di Iorio S. . Comprehensive analysis on the effect of lube oil on particle emissions through gas exhaust measurement and chemical characterization of condensed exhaust from a DI SI engine fueled with hydrogen. International Journal of Hydrogen Energy, 2023, 48(58): 22277–22287

[94] Thawko A, Yadav H, Shapiro M. . Effect of lubricant formulation on characteristics of particle emissions from engine fed with a hydrogen-rich fuel. SAE Technical Paper 2020-01-2200, 2020,

[95] HaupaisA. Combustion dans les moteurs Diesel, Techniques de l'ingénieur. 1992

[96] Marchal C. Modelling of soot formation and oxidation in an automotive engine. Dissertation for the Doctoral Degree. Orleans: University of Orléans, 2008,

[97] ApicellaB, Catapano F, Di IorioS, et al. Comprehensive analysis on the effect of lube oil on particle emissions through gas exhaust measurement and chemical characterization of condensed exhaust from a DI SI engine fueled with hydrogen. Part 2: Effect of operating conditions. International Journal of Hydrogen Energy, 2024, 49B: 968–979

[98] Wei Y, Wang K, Wang W. . Comparison study on the emission characteristics of diesel- and dimethyl ether-originated particulate matters. Applied Energy, 2014, 130: 357–369

[99] Wang Y, Liang X, Wang K. . Effect of base oil on the nanostructure and oxidation characteristics of diesel particulate matter. Applied Thermal Engineering, 2016, 106: 1311–1318

[100] Tan P, Li Y, Shen H. Effect of lubricant sulfur on the morphology and elemental composition of diesel exhaust particles. Journal of Environmental Sciences, 2017, 55: 354–362

[101] Wang Y, Chen Y, Liang X. . Impacts of lubricating oil and its formulations on diesel engine particle characteristics. Combustion and Flame, 2021, 225: 48–56

[102] Liang X, Wang Y, Wang Y. . Impact of lubricating base oil on diesel soot oxidation reactivity. Combustion and Flame, 2020, 217: 77–84

[103] Dong L, Shu G, Liang X. Effect of lubricating oil on the particle size distribution and total number concentration in a diesel engine. Fuel Processing Technology, 2013, 109: 78–83

[104] Lyu X, Liang X, Wang Y. . Influence of lubricants on particulate matter emission from internal combustion engines: A review. Fuel, 2024, 366: 131317

[105] Haynes B S, Wagner H G. Soot formation. Progress in Energy and Combustion Science, 1981, 7(4): 229–273

[106] Haynes B S, Jander H, Mätzing H. . The influence of gaseous additives on the formation of soot in premixed flames. Symposium (International) on Combustion, 1982, 19: 1379–1385

[107] Boyette W R, Steinmetz S A, Guiberti T F. . Soot formation in turbulent flames of ethylene/hydrogen/ammonia. Combustion and Flame, 2021, 226: 315–324

[108] Zaher M H, Dadsetan M, Chu C. . The effect of ammonia addition on soot nanostructure and composition in ethylene laminar flames. Combustion and Flame, 2023, 251: 112687

[109] Chen C, Liu D. Review of effects of zero-carbon fuel ammonia addition on soot formation in combustion. Renewable & Sustainable Energy Reviews, 2023, 185: 113640

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