Exploring the Engine Performance Potentials of Cotton (Gossypium sp) Seed Oil-AMAs Blends for Sustainable Lubricants Development

Abstract

Aim: This study investigated blended cottonseed oil's potential as a sustainable lubricant for internal combustion engines. Study Design, Place and Duration of Study: The experiment, conducted in Nigeria at Abubakar Tafawa Balewa University, Federal Polytechnic Bauchi, and Nenis Automobile Engineering Workshop, Lagos, involved both experimental analysis and engine performance testing on a JF 168 gasoline engine test-bed with an A.C. dynamometer. Methodology: Physicochemical properties, fatty acid composition, and blending characteristics with an after-market additive (AMAs) were analysed. Following standard procedures outlined in SAE J1349 and SAE J1995 test protocols, the engine's performance characteristics were evaluated across a speed range of 2000 rpm to 4000 rpm, with measurements taken at 500 rpm increments after each hour of engine operation. Results:  The analysis revealed that cottonseed oil has a golden yellow color, a lower refractive index (1.471), a higher relative density (0.93), and a significantly lower kinematic viscosity (18 cSt) compared to mineral oils. Its high iodine value (114.86 g I2/100g) classifies it as a semi-drying oil with high unsaturation, and its high saponification value (190.18 mg KOH/g) suggests good boundary lubrication potential. Optimal blending stability with an aftermarket additive (AMAs) was observed within a 30-55% cottonseed oil ratio. Engine performance tests using a B40 blended cottonseed oil at maximum speed (4000 rpm) showed superior brake power (4.86 kW) and lower specific fuel consumption (77.52 g/kW-h) compared to both monograde and multigrade oils, indicating improved fuel economy and thermal efficiency. However, it yielded lower torque (11.09 Nm) than the manufacturer's specification (17.6 Nm, a trend also observed with mineral oils) and a generator efficiency (20.18%) lower than multigrade oil (24.02%). Conclusion: Blended cottonseed oil boosts power and fuel efficiency on one hand, while its lower viscosity requires modification to optimize lubrication and engine performance. These findings align with SDGs 7, 9, and 12, and further research is required for its optimization as a viable engine lubricant.