Robust, Policy-Tunable Optimization of Diesel Plastic Fuel/α-Terpineol Blends Across the Duty Map

Satyasaibaba Pitta; Bharath Raju Lodd Battu; Mallikarjunachari Gangapuram; Sai Srikanth Vemuri; Prabhu Kishore Nutakki; Prasad Kumar Putha

doi:10.29194/NJES.29020371

Authors

Satyasaibaba Pitta Department of Mechanical Engineering, University College of Engineering, JNTUK, Kakinada-533003, Andhra Pradesh, India.
Bharath Raju Lodd Battu Department of Mechanical Engineering, Malla Reddy Technical Campus (A Constituent Unit of Malla Reddy Vishwavidyapeeth, Deemed to be University), Hyderabad-500014, India.
Mallikarjunachari Gangapuram Department of Mechanical Engineering, PACE Institute of Technology and Sciences (A), Ongole-523272, India.
Sai Srikanth Vemuri Department of Mechanical Engineering, Mallareddy College of Engineering and Technology, Hyderabad-500100, India.
Prabhu Kishore Nutakki Department of Mechanical Engineering, MLR Institute of Technology, Hyderabad-500043, India.
Prasad Kumar Putha Department of Mechanical Engineering, VNR Vignana Jyothi Institute of Engineering and Technology, Hyderabad-500090, India.

DOI:

https://doi.org/10.29194/NJES.29020371

Keywords:

Diesel plastic fuel, Α-Terpineol, Conditional Value at Risk, Quantile Based Desirability Functions, Worst Case Performance, Engine Calibration Robustness

Abstract

This study establishes a risk aware, multi objective methodology to select diesel plastic fuel α-terpineol blends that deliver robust engine performance across operating loads in a common rail direct injection diesel engine. Heterogeneous responses brake thermal efficiency, brake specific fuel consumption, oxides of nitrogen, carbon monoxide, hydrocarbons, smoke, and exhaust gas temperature are mapped to a unitless desirability scale and aggregated by load. Conditional Value at Risk across loads then prioritizes worst case behavior. By Conditional Value at Risk at level 0.20, the ranking is: diesel 0.242, diesel plastic fuel with 15% α-terpineol 0.197, 10% α-terpineol is 0.177, 5% α-terpineol is 0.157, diesel plastic fuel is 0.141, waste plastic fuel is 0.081. Relative to neat diesel plastic fuel, worst-case performance improves by 11% at 5% α-terpineol, 26% at 10% α-terpineol, and 40% at 15% α-terpineol, with the 100% load consistently governing the tail. Average brake specific fuel consumption decreases from 0.4553 to 0.4217 kg/kWh at 15% α-terpineol, average exhaust gas temperature falls from 321.4 to 293.0°C. Duty map mean oxides of nitrogen reduce from 512 to 474 ppm, hydrocarbons fall from 42.67 to 35.73 ppm. At full load, carbon monoxide declines from 0.52 to 0.46 %vol., and smoke opacity decreases from 52.28 to 49.71%. Within the tested window, 15% α-terpineol in diesel plastic fuel is the risk aware first choice, with 10% α-terpineol a near optimal alternative. The methodology remains stable under risk aversion and weighting changes at high-load calibration.

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