Enhancing tribological performance of electric vehicle lubricants: Nanoparticle-enriched palm oil biolubricants for wear resistance

Abstract

The transition to electric vehicles (EVs) calls for sustainable advancements in automotive lubricants, as traditional fossil-fuel-based products pose environmental challenges. Palm oil-based biolubricants enriched with nanoparticles present a promising eco-friendly alternative that meets the thermal and tribological demands of EVs. This paper aims to analyze the development of nanoparticle-enriched palm oil-based biolubricants, aimed at improving the sustainability and performance of electric vehicle (EV) lubrication systems. The critical findings highlight that integrating nanoparticles such as graphene, titanium dioxide, and aluminum oxide into palm oil-based lubricants significantly enhances their tribological properties. These enhancements include a 26.21%-34% reduction in coefficient of friction (COF), a 12.99%-30% reduction in wear, and improved thermal stability. The study found that nanoparticle-enriched biolubricants outperformed traditional options in terms of friction and wear under high-temperature and pressure conditions, as supported by regression analysis. The study demonstrates that nanoparticle-enriched biolubricants offer a viable eco-friendly alternative to conventional lubricants, lowering the environmental impact by reducing greenhouse gas emissions and energy consumption. This innovation has significant implications for both the environment and industry, offering a sustainable solution that reduces dependency on fossil fuels, enhances EV efficiency, and aligns with global sustainability goals. Besides, this paper discusses biolubricants drawbacks and future studies direction.

Keywords: COF; Electric vehicle lubricants; Palm oil-based lubricants; Tribological performance; Wear.

Fig. 1

Research flowchart.

Fig. 2

The largest of global palm oil producers [46].

Fig. 3

Global palm oil production distribution [46].

Fig. 4

Growth of the Indonesian palm oil industry over ten years (2013–2022) [46].

Fig. 5

Key factors influencing biolubricants.

Fig. 6

Main parts of palm fruit.

Fig. 7

Chemical modification process flow of biolubricants synthesis [42]. Reprinted with permission from MDPI under an open access Creative Common CC by license.

Fig. 8

Experimental configuration utilized in the synthesis of biolubricants [63]. Reprinted with permission from Elsevier.

Fig. 9

Diverse additives influencing biolubricants characteristics [69]. Reprinted with permission from Elsevier.

Fig. 10

Viscosity of various biolubricants in different temperatures assessment [84]. Reprinted with permission from Elsevier.

Fig. 11

Various biolubricants exhibit Newtonian behavior of (a) sunflower, (b) soybean, (c) Jatropha, and (d) waste oils [84]. Reprinted with permission from Elsevier.

Fig. 12

Factors influencing biolubricants' oxidation stability.

Fig. 13

Thermogravimetric Analysis (TGA) plot depicting the thermal decomposition behavior of dihydroxy product (HPEE-CP) in a nitrogen environment [115]. Reprinted with permission from Elsevier.

Fig. 14

Physicochemical assessment: (a) Relationship between viscosity index and concentration of waste cooking oil (WCO), and (b) Relationship between viscosity index and concentration of additives [116]. Reprinted with permission from Elsevier.

Fig. 15

Life Cycle Assessment cycle.

Fig. 16

Two-step method schematic diagram.

Fig. 17

Results of coefficient of friction evaluation for pure PAO and PAO-CNCs-based lubricants over different time intervals [159]. Reprinted with permission from Elsevier.

Fig. 18

Time-dependent coefficient of friction curves observed during the lubrication of pentaerythritol ester (PE) with 0.5% TCP or varying concentrations of SiO₂-PIL [161]. Reprinted with permission from Elsevier.

Fig. 19

Effect of additive TiO₂ and Sliding speed on the Coefficient of friction of the bio-nanolubricants [162]. Reprinted with permission from Elsevier.

Fig. 20

Lubrication schematic using biolubricants.

Fig. 21

Lubrication schematic using nano-biolubricants.