Multiobjective Optimization of Hydrogen‐Assisted <i>Calophyllum inophyllum</i> Biodiesel Operation in a Compression Ignition Engine

ABSTRACT This study investigates operating conditions for a diesel engine running in tri‐fuel mode with diesel, Calophyllum inophyllum biodiesel (0–30 vol%), and inducted hydrogen (0–15 L·min − 1 ) over 0%–100% load (20% steps), yielding 96 steady‐state points. Brake thermal efficiency (BTE), brake‐specific fuel consumption, exhaust gas temperature, and regulated emissions (NO x , HC, CO, CO 2 , and smoke) were measured. To avoid dependence on a single, fixed objective weighting, Bootstrapped Empirical Multiobjective Ranking and Selection (BEMORS) was applied using percentile scaling, Pareto screening, and Dirichlet preference weights under baseline, NO x ‐biased, and NO x , along with smoke‐biased scenarios. Stochastic Multicriteria Acceptability Analysis benchmarking was used to check ranking consistency. Hydrogen enrichment increased BTE and decreased CO, HC, and smoke across loads, while tending to increase NO x . Increasing biodiesel fraction has also decreased smoke, CO, and HC, but increased fuel consumption due to lower heating value. BEMORS identified 40% load with high hydrogen induction and low biodiesel fraction as the compromise across preference scenarios, whereas high‐load hydrogen addition scenarios were attractive when smoke scenarios dominate priorities. Combining tri‐fuel experiments with preference‐uncertain selection provides practical and implementable operating corridors that are competitive when regulatory emphasis shifts and quantifies the suitability of recommendations within the tested steady‐state conditions.