Biofuels and Tribology: Pathways Toward Sustainable Engine Performance

Abstract

The rapid increase in automobile usage has accelerated the depletion of fossil fuels and contributed significantly to environmental degradation. This scenario highlights the urgent need for alternative energy resources that can meet growing energy demands while reducing harmful emissions from conventional fuels. Among the various alternatives, biofuels have emerged as a promising option for internal combustion engines. Numerous short-term engine tests using biofuels have shown encouraging results; however, challenges persist in long-term engine durability tests, which often reveal issues such as excessive carbon deposition and contamination of lubricating oils, ultimately leading to engine failure.
This review aims to evaluate the tribological feasibility of biofuels in transportation applications, as their tribological performance plays a critical role in engine reliability and efficiency. The discussion focuses on various tribological aspects, including material compatibility, long-term endurance, wear behavior, and frictional characteristics. A detailed analysis of friction and wear parameters is presented, covering both compression ignition and spark ignition engines, with particular attention to the use of biodiesels, biofuels, and bio-oils as potential lubricants.
Rather than introducing new experimental findings, this review consolidates and critically analyzes existing research, outlining past developments and highlighting future perspectives in the field of biofuel tribology.