Optimization of Efficiency and Emissions in Otto Engines Through the Characterization of Spark Plugs and Fuels under Extreme Altitude Conditions

This study aims to identify the optimal ignition parameters that enhance the performance and environmental efficiency of a 2.7 L spark-ignition engine under high-altitude conditions (≈2560 m a.s.l.). The influence of spark-plug electrical resistance, electrode calibration, and fuel octane rating on torque, power, and pollutant emissions was analyzed using a factorial experimental design supported by ANOVA and multiple regression models. Tests were conducted on a MAHA LPS 3000 chassis dynamometer, following Ecuadorian standard INEN 0960, using platinum and copper spark plugs with fuels rated at 85, 89, and 92 RON. The results showed that platinum spark plugs increased maximum power from 28.9 kW to 31.2 kW and torque from 110.5 Nm to 119.1 Nm, while reducing HC emissions by 50.47 %, CO by 6.97 %, and specific fuel consumption by 4.12 % compared with conventional copper spark plugs. Platinum spark plugs, due to their composition and fine-electrode design, produce a more stable and powerful spark that improves fuel ignition, leads to more complete combustion and reduces pollutants such as CO and HC. This effect is amplified with higher-octane fuels, which increase ignition stability and thermal efficiency. The predictive models developed provide a useful tool for vehicle calibration, emission control, and optimization of spark-ignition systems in high-altitude Andean regions.