https://nova.newcastle.edu.au/vital/access/ /manager/Index en-au 5 https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:23832 Sat 24 Mar 2018 07:12:13 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:52062 The urgent need for drastic reduction in emissions due to global warming demands a radical energy transition in transportation. The role of biofuels is fundamental to bridging the current situation towards a clean and sustainable future. In passenger cars, the use of ethanol fuel reduces gas emissions (CO2 and other harmful gases), but can bring tribological challenges to the engine. This review addresses the current state-of-the-art on the effects of ethanol fuel on friction, lubrication, and wear in car engines, and identifies knowledge gaps and trends in lubricants for ethanol-fuelled engines. This review shows that ethanol affects friction and wear in many ways, for example, by reducing lubricant viscosity, which on the one hand can reduce shear losses under full film lubrication, but on the other can increase asperity contact under mixed lubrication. Therefore, ethanol can either reduce or increase engine friction depending on the driving conditions, engine temperature, amount of diluted ethanol in the lubricant, lubricant type, etc. Ethanol increases corrosion and affects tribocorrosion, with significant effects on engine wear. Moreover, ethanol strongly interacts with the lubricant’s additives, affecting friction and wear under boundary lubrication conditions. Regarding the anti-wear additive ZDDP, ethanol leads to thinner tribofilms with modified chemical structure, in particular shorter phosphates and increased amount of iron sulphides and oxides, thereby reducing their anti-wear protection. Tribofilms formed from Mo-DTC friction modifier are affected as well, compromising the formation of low-friction MoS2 tribofilms; however, ethanol is beneficial for the tribological behaviour of organic friction modifiers. Although the oil industry has implemented small changes in oil formulation to ensure the proper operation of ethanol-fuelled engines, there is a lack of research aiming to optimize lubricant formulation to maximize ethanol-fuelled engine performance. The findings of this review should shed light towards improved oil formulation as well as on the selection of materials and surface engineering techniques to mitigate the most pressing problems.]]> Mon 29 Jan 2024 18:20:49 AEDT ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:36404 iC₈)₂PO₂) diluted in octane lubricated as effectively as pure IL. However, until now the structure and composition of the lubricating adsorbed layer, which is critical for lubrication, was unknown. Here, the unconfined structure of the IL adsorbed layer at the oil-silica interface has been studied using neutron reflectometry. Multiple neutron contrasts revealed an 8 Å thick adsorbed layer, even at 60 and 80 °C. The ratio of cations and anions in the layer was investigated by synthesizing the IL with deuterated cations and measuring its reflectivity at the oil-silica interface. At 60 °C the layer was composed of 48 ± 6 mol % P₆,₆,₆,₁₄⁺ cations, 24 ± 2 mol % (ⁱC⁸)₂PO₂⁻ anions, and 28 ± 8 mol % octane, while at 80 °C the composition was 50 ± 2 mol % P₆,₆,₆,₁₄⁺, 28 ± 2 mol % (ⁱC₈)₂PO₂⁻ anions, and 22 ± 2 mol % octane. These results reinforce the importance of the judicious selection of IL cations and anions for charged surfaces and support their use in high-temperature applications.]]> Mon 27 Apr 2020 13:54:03 AEST ]]> https://nova.newcastle.edu.au/vital/access/ /manager/Repository/uon:24748 Fri 16 Aug 2024 16:22:32 AEST ]]>