A novel analysis of n-butanol–gasoline blends impact on spark ignition engine characteristics and lubricant oil degradation

ABSTRACT

Butanol emerges as a potential biofuel for energizing modern automobiles. Its impact on engine performance and emission characteristics was investigated by many researchers. However, a research gap exists for its effect on lubricating oil deterioration. Therefore, n-butanol–gasoline blends were prepared with 6% and 12% by volume of alcohol (B6 and B12) and compared with pure gasoline (B0) in terms of engine performance, emissions, and lube oil condition. The engine performance along with exhaust gas temperature increased with an increasing ratio of butanol in the fuel blend. CO and HC emissions were the lowest in the case of B12 followed by B6 and B0. Furthermore, lubricating oil properties were determined to monitor its deterioration rate. The kinematic viscosity at 100°C and flash point temperature showed a minimum reduction in the case of B12, i.e., 22% and 16%, respectively, as compared to fresh oil. The highest concentration of wear elements in lube oil was detected for B12 fuel, which included Al (11 × 10⁻⁶), Fe (27 × 10⁻⁶), Cr (4 × 10⁻⁶), and Cu (13 × 10⁻⁶). Similarly, the additive counts for Ca, Mg, and Zn were found to be 1665 × 10⁻⁶, 7.3 × 10⁻⁶, and 730 × 10⁻⁶, respectively, in lubricating oil for B12. Therefore, advanced lubricating oil should be developed for alternative fuels to improve its lifecycle.

KEYWORDS:

• Biofuels
• butanol
• energy extraction
• oil additives
• wear metals

Nomenclature

Al, Aluminum; ASTM, American Society for Testing Materials; BP, brake power; BSEC, brake-specific energy consumption; BSFC, brake-specific fuel consumption; BTE, brake thermal efficiency; B0, pure gasoline; B3, 3% butanol and 97% gasoline mixture by volume; B6, 6% butanol and 94% gasoline mixture by volume; B7, 7% butanol and 93% gasoline mixture by volume; B10, 10% butanol and 90% gasoline mixture by volume; B12, 12% butanol and 88% gasoline mixture by volume; B20, 20% butanol and 80% gasoline mixture by volume; B30, 30% butanol and 70% gasoline mixture by volume; B35, 35% butanol and 65% gasoline mixture by volume; Ca, calcium; cc, cubic centimeter; CO, carbon monoxide; CO₂, carbon dioxide; Cr, chromium; CR, compression ratio; Cu, copper; EGT, exhaust gas temperature; E10, 10% ethanol and 90% gasoline mixture by volume; E10B5, 10% ethanol, 5% butanol, and 85% gasoline mixture by volume; E10B10, 10% ethanol, 10% butanol, and 80% gasoline mixture by volume; E10B15, 10% ethanol, 15% butanol, and 75% gasoline mixture by volume; E85, 85% ethanol and 15% gasoline mixture by volume; Fe, Iron; GDI, gasoline direct injection; GHG, greenhouse gas; HC, hydrocarbon; IC, internal combustion; LHV, lower heating value; Mg, magnesium; NO_x, oxides of nitrogen; P, phosphorus; PSO, Pakistan State Oil; RPM, revolution per minute; SAE, Society of Automotive Engineers; SI, spark ignition; TBN, total base number; UHC, unburnt hydrocarbon; VI, viscosity index; ZDDP, zinc dialkyl dithiophosphate; Zn, zinc.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Declaration of Conflicting interests

The authors declare that there is no conflict of interest.