RESUMEN
The automotive industry continuously enhances vehicle design to meet the growing demand for more efficient vehicles. Computational design and numerical simulation are essential tools for developing concept cars with lower carbon emissions and reduced costs. Underground roads are proposed as an attractive alternative for reducing surface congestion, improving traffic flow, reducing travel times and minimizing noise pollution in urban areas, creating a quieter and more livable environment for residents. In this context, a concept car body design for underground tunnels was proposed, inspired by the mako shark shape due to its exceptional operational kinetic qualities. The proposed biomimetic-based method using computational fluid dynamics for engineering design includes an iterative process and car body optimization in terms of lift and drag performance. A mesh sensitivity and convergence analysis was performed in order to ensure the reliability of numerical results. The unique surface shape of the shark enabled remarkable aerodynamic performance for the concept car, achieving a drag coefficient value of 0.28. The addition of an aerodynamic diffuser improved downforce by reducing 58% of the lift coefficient to a final value of 0.02. Benchmark validation was carried out using reported results from sources available in the literature. The proposed biomimetic design process based on computational fluid modeling reduces the time and resources required to create new concept car models. This approach helps to achieve efficient automotive solutions with low aerodynamic drag for a low-carbon future.
RESUMEN
In this research, the performance and emissions of a four-stroke spark ignition engine fuelled with varying proportion of propanol-camphor and gasoline blends were investigated. The physicochemical properties such as specific gravity, viscosity, fire point, flash point, and iodine value (I.V.) of the blends were determined, and the values obtained conform to the ASTM standard. Sample P0B (100% of pure gasoline and 5 g of camphor) had the best physicochemical property values higher than those of the least sample of P15B by the following percentages: specific gravity (0.5%), viscosity (30.8%), fire point (5.08%), flash point (21.8%), and I.V. sample (0.5%). Also, the engine performance parameters such as brake power, brake thermal efficiency, brake mean effective pressure (BMEP), and specific fuel consumption were generated from the engine-measured parameters. Sample P0B has the best specific fuel consumption for the torque of 3 N m with a value of 22.77 kg/kW h, and sample P0A (100% of pure gasoline) has the best fuel consumption for a torque of 6 N m with a value of 12.52 kg/kW h. For brake thermal efficiency, sample P0B gives the best brake thermal efficiency at the two constant torques with a value of 0.36 for torque 3 N m and 0.67 for torque 6 N m. Sample P15C (85% of gasoline, 15% of propanol, and 5 g of camphor) gives the best BMEP at torque 3 N m with a value of 1.92 bar, and sample P5C (95% of gasoline, 5% of propanol, and 10 g of camphor) gives the best BMEP at 6 N m with a value of 3.85 bar. Exhaust emissions were analyzed for unburned hydrocarbon (HC), carbon monoxide (CO), carbon dioxide (CO2), and nitrogen oxide (NOx). The results showed that increasing the blending percentage reduces the emitted concentration of CO, HC, and NOx. Carbon monoxide emission was found to be lowest at sample P10A (90% of gasoline and 10% of propanol) for torque 3 N m with a value of 0.16, and at torque 6 N m, the sample with the lowest percentage was P15C with a percentage of 0.21.